Anti-overturning bolt sleeve structure

Abstract

The utility model discloses an anti-overturning bolt sleeve structure which comprises a bolt sleeve (3) and an exhaust pipe fixing part (4), the bolt sleeve (3) abuts against the upper side of the exhaust pipe fixing part (4) and is fixedly connected with the exhaust pipe fixing part (4) through a bolt (1), the anti-overturning bolt sleeve structure further comprises a bolt sleeve assembly, and the bolt sleeve assembly is of an I-shaped structure and comprises a connecting arm (6). The bolt sleeves (3) are installed at the two ends of the connecting arm (6), each bolt sleeve is provided with an axial cavity (3-3), the bottom of each bolt sleeve is provided with a bolt sleeve foot (3-2), and each bolt sleeve foot (3-2) is of a circular ring structure and is coaxial with the corresponding bolt sleeve (3); a counter bore matched with the circular ring is formed in the joint face of the exhaust pipe fixing part (4) and the bolt sleeve, and a concave-convex tenon matching structure is formed. The exhaust pipe fastening structure has the advantages that the structure is compact, the pressure stress of the bolt sleeve and the extra stress borne by the bolt can be reduced, and therefore the reliability of the exhaust pipe fastening structure is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of engine assembly, in particular to an anti-overturning bolt sleeve structure. Background Art

[0002] When the engine is working, the exhaust pipe and the cylinder head are connected by bolts. The high-temperature exhaust gas enters the exhaust pipe, which will increase the temperature of the exhaust pipe. In order to reduce the temperature of the bolts and avoid the decrease of the bolt axial force due to high-temperature creep, a bolt sleeve is usually added between the exhaust pipe and the bolts to avoid direct contact between the bolts and the high-temperature exhaust pipe. Generally, the longer the bolt sleeve, the better the thermal insulation effect. The temperature difference between the exhaust pipe and the cylinder head is large. At the same time, the expansion coefficients of the materials selected for the two are different in most cases. Under thermal expansion and contraction, the exhaust pipe will move relative to the cylinder head. The two ends of the bolt sleeve, one end contacts the exhaust pipe, and the other end contacts the flange surface of the fastening bolt. Therefore, the upper and lower end faces of the bolt sleeve are subjected to a friction force in opposite directions, thereby generating a rotational torque on the bolt sleeve, which will cause abnormal stress at the corners of the bolt sleeve. At the same time, it will generate an additional tensile force on the bolt, which may eventually cause the bolt sleeve to collapse and the bolt to break. Utility Model Content

[0003] The utility model mainly aims to provide an anti-overturning bolt sleeve structure which reduces the compressive stress of the bolt sleeve and the additional stress on the bolt by increasing the anti-overturning force arm of the bolt sleeve, thereby ensuring the reliability of the exhaust pipe fastening structure.

[0004] To this end, the utility model proposes an anti-overturning bolt sleeve structure.

[0005] Preferably, the utility model may also have the following technical features:

[0006] An anti-overturning bolt sleeve structure comprises a bolt sleeve and an exhaust pipe fixing portion, wherein the bolt sleeve abuts against the upper side of the exhaust pipe fixing portion and is fixed by bolt connection, and further comprises a bolt sleeve assembly, wherein the bolt sleeve assembly is in an "I"-shaped structure and comprises a connecting arm and the bolt sleeves installed at both ends of the connecting arm, wherein the bolt sleeve is provided with an axial cavity (3-3) and a bolt sleeve foot is provided at the bottom, wherein the bolt sleeve foot is a circular ring structure and is coaxial with the bolt sleeve; a countersunk hole matched with the circular ring is provided on the joint surface of the exhaust pipe fixing portion and the bolt sleeve, forming a concave-convex tenon matching structure.

[0007] Furthermore, it also includes a stabilizing washer, which is installed on the upper part of the bolt sleeve and includes a washer and an annular ring. The bottom of the washer is provided with an annular ring, and the outer wall of the annular ring is provided with threads.

[0008] Furthermore, a plurality of vent holes are formed on the side wall of the cavity, and the vent holes extend in the radial direction of the bolt sleeve.

[0009] Furthermore, the inner wall of the bolt sleeve foot is provided with an internal thread connected to the bolt.

[0010] Furthermore, a side wall of the bolt sleeve is provided with a limiting protrusion facing downward, and one side of the limiting protrusion (3-4) is attached to the outer side of the exhaust pipe fixing portion.

[0011] Furthermore, the bolt sleeve, the connecting arm, the bolt sleeve foot and the limiting protrusion are integrally cast.

[0012] Furthermore, the limiting protrusion is a vertical flat plate.

[0013] Furthermore, the limiting protrusion is an arc-shaped piece, and its curvature matches the outer side of the exhaust pipe fixing part.

[0014] Furthermore, the limiting protrusion is arranged directly below the connecting arm.

[0015] Compared with the prior art, the beneficial effects of the utility model include: reducing the compressive stress of the bolt sleeve and the additional stress on the bolt by increasing the anti-overturning force arm of the bolt sleeve, thereby ensuring the reliability of the exhaust pipe fastening structure.

[0016] There are cavities and air vents inside the bolt sleeve to form a heat-insulating effect and allow air to circulate, which can effectively reduce the temperature of the bolts and the bolt sleeves and prevent the structure from being damaged due to excessive temperature during operation. The use of stabilizing washers and bolt sleeve feet can not only increase the contact area to increase friction and prevent the bolts from loosening, but also prevent the exhaust pipe from moving in relative position and avoid bolt breakage; the role of the limiting bump is to further limit the lateral movement and circumferential rotation of the bolt sleeve to keep the position of the bolt sleeve stable and unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A three-dimensional schematic diagram of the existing design;

[0018] Figure 2 A sectional view of the main view of the existing design;

[0019] Figure 3 It is a three-dimensional schematic diagram of the bolt sleeve of the utility model;

[0020] Figure 4 It is a cross-sectional view of the front view of the utility model equipped with a bolt sleeve;

[0021] Figure 5 It is a cross-sectional view of the main view of the optimized bolt sleeve of the utility model;

[0022] Figure 6 It is a front view of the stabilizing washer of the utility model.

[0023] Description of Reference Numerals

[0024] 1. Bolt; 2. Stabilizing washer; 2-1. Washer; 2-2. Circular ring; 3. Bolt sleeve; 3-1. Vent hole; 3-2. Bolt sleeve foot; 3-3. Cavity; 3-4. Limiting bump; 4. Exhaust pipe fixing part; 5. Cylinder head; 6. Connecting arm. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific implementations and in conjunction with the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0026] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein like reference numerals refer to like parts unless otherwise specifically stated.

[0027] like Figures 3 to 6 The anti-overturning bolt sleeve structure shown includes a bolt 1, an exhaust pipe fixing part 4 and a cylinder head 5. The bottom of the exhaust pipe fixing part 4 is provided with a cylinder head 5. The exhaust pipe fixing part 4 is provided with a threaded through hole. The cylinder head 5 is provided with a threaded countersunk hole. It also includes a bolt sleeve assembly and a stabilizing washer 2. The bolt sleeve assembly is in an "I"-shaped structure, including a connecting arm and a bolt sleeve 3 integrally formed at both ends of the connecting arm. Among them, the connecting arm is a long strip structure with a certain strength, such as a square bar, a round rod, etc. A stabilizing washer 2 is provided on the top of the bolt sleeve 3, and a bolt 1 is provided in the stabilizing washer 2. A cavity 3-3 is provided inside the bolt sleeve 3, and a plurality of vents 3-1 are provided on the side wall of the cavity 3-3. The vents 3-1 are arranged along the radial direction of the bolt sleeve. The bottom of the bolt sleeve 3 is provided with an exhaust pipe fixing part 4. After the bolt 1 passes through the stabilizing washer 2, it passes through the threaded through holes of the bolt sleeve 3 and the exhaust pipe fixing part 4 in sequence. Finally, the end of the bolt 1 is screwed into the threaded hole of the cylinder head 5. The joint surface of the exhaust pipe fixing part 4 and the bolt sleeve is provided with a countersunk hole matched with the circular ring to form a concave-convex tenon matching structure, which can improve the connection efficiency of the bolt sleeve 3 and the exhaust pipe fixing part on the one hand, and can also play a limiting role on the other hand.

[0028] The stabilizing washer 2 is composed of a washer 2-1 and an annular ring 2-2, wherein the annular ring 2-2 is provided with a through hole to fit the bolt 1, and the outer wall of the annular ring 2-2 is also provided with an external thread connected to the bolt sleeve 3. One end of the annular ring is provided with a flange surface, and the flange surface forms the washer 2-1. During installation, the annular ring 2-2 is connected to the upper end of the bolt sleeve 3 through its external thread.

[0029] The inner wall of the bolt sleeve foot 3-2 is provided with an internal thread connected to the bolt 1. Preferably, the side wall of the bolt sleeve 3 is provided with a limiting protrusion 3-4 facing downward. Further, the bolt sleeve 3, the connecting arm 6, the bolt sleeve foot 3-2 and the limiting protrusion 3-4 are integrally cast.

[0030] Specifically, the limiting protrusions 3-4 are arranged directly below the connecting arm 6, and are vertical flat plates or arc-shaped plates, or other irregular shapes, and the curvature of the arc-shaped plates matches the outer side of the exhaust pipe fixing portion 4. The limiting protrusions further limit the lateral movement and circumferential rotation of the bolt sleeve, so that the position of the bolt sleeve is kept stable and unchanged.

[0031] Depend on Figure 1 and Figure 2 It can be seen that due to the difference in thermal expansion and contraction and expansion coefficient, the exhaust pipe will move relative to the cylinder head at high temperature, for example, to the left. The friction Fm1 and Fm2 between the bolt sleeve, the exhaust pipe and the bolt will produce a clockwise rotation torque on the bolt sleeve, thereby generating two pressures Fy1 and Fy2 to produce a counterclockwise rotation torque to counteract it, achieving torque balance. In order to avoid the collapse of the bolt sleeve and the breaking of the bolt, the smaller the Fy1 and Fy2, the better.

[0032] The size of Fy1 and Fy2 is not only related to the friction forces Fm1 and Fm2, but also to the length of the force arm of each force (the distance between the force vector and the center of rotation). The shorter the bolt sleeve and the larger the diameter of the bolt sleeve, the smaller Fy1 and Fy2.

[0033] This embodiment provides a bolt sleeve structure, which can increase the anti-overturning arm of the bolt sleeve, thereby reducing the pressure generated at both ends of the bolt sleeve. In this embodiment, the two bolt sleeves are made into one piece, which greatly increases the arm lengths of Fy1 and Fy2, while the arm lengths of Fm1 and Fm2 do not change (the two bolt sleeves are the same), thereby achieving the purpose of reducing Fy1 and Fy2.

[0034] At the same time, the displacements caused by thermal expansion and contraction at the contact position between the exhaust pipe and the two bolt sleeves are not consistent, and the resultant friction force is smaller than the resultant friction force of the two separated bolt sleeves, which reduces Fm1 and Fm2 to a certain extent, thereby further reducing Fy1 and Fy2.

[0035] Those skilled in the art will appreciate that numerous variations to the above description are possible, and that the examples and figures are intended only to describe one or more specific implementations.

[0036] Although exemplary embodiments of the present invention have been described and described, it will be understood by those skilled in the art that various changes and substitutions may be made thereto without departing from the spirit of the present invention. In addition, many modifications may be made to adapt specific situations to the teachings of the present invention without departing from the central concept of the present invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but the present invention may also include all embodiments and their equivalents that fall within the scope of the present invention.

Claims

1. An anti-overturning bolt sleeve structure, comprising a bolt sleeve (3) and an exhaust pipe fixing portion (4), wherein the bolt sleeve (3) abuts against the upper side of the exhaust pipe fixing portion (4) and is connected and fixed by bolts (1), characterized in that: It also includes a bolt sleeve assembly, which is in the shape of an "I" character, and includes a connecting arm (6), and the bolt sleeves (3) installed at both ends of the connecting arm (6), the bolt sleeve is provided with an axial cavity (3-3), and a bolt sleeve foot (3-2) is provided at the bottom, the bolt sleeve foot (3-2) is a circular ring structure, and is coaxial with the bolt sleeve (3); the joint surface of the exhaust pipe fixing portion (4) and the bolt sleeve is provided with a countersunk hole matched with the circular ring, forming a concave-convex tenon matching structure.

2. The anti-overturning bolt sleeve structure according to claim 1, characterized in that: It also includes a stabilizing washer, the stabilizing washer (2) being installed on the upper part of the bolt sleeve, and comprising a washer (2-1) and a circular ring (2-2), the bottom of the washer (2-1) being provided with a circular ring (2-2), and the outer wall of the circular ring (2-2) being provided with threads.

3. The anti-overturning bolt sleeve structure according to claim 1, characterized in that: A plurality of vent holes (3-1) are provided on the side wall of the cavity (3-3).

4. The anti-overturning bolt sleeve structure according to claim 1, characterized in that: The inner wall of the bolt sleeve foot (3-2) is provided with an internal thread for connecting with the bolt (1).

5. The anti-overturning bolt sleeve structure according to claim 1, characterized in that: The side wall of the bolt sleeve (3) is provided with a limiting protrusion (3-4) facing downwards, and one side of the limiting protrusion (3-4) is attached to the outer side of the exhaust pipe fixing part (4).

6. The anti-overturning bolt sleeve structure according to claim 5, characterized in that: The bolt sleeve (3), the connecting arm (6), the bolt sleeve foot (3-2) and the limiting protrusion (3-4) are integrally cast.

7. The anti-overturning bolt sleeve structure according to claim 5, characterized in that: The limiting protrusion (3-4) is a vertical flat plate.

8. The anti-overturning bolt sleeve structure according to claim 5, characterized in that: The limiting protrusion (3-4) is an arc-shaped piece, and its curvature matches the outer side of the exhaust pipe fixing part (4).

9. The anti-overturning bolt sleeve structure according to claim 5, characterized in that: The limiting protrusion (3-4) is arranged directly below the connecting arm (6).

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