Diesel exhaust pipe clamp, method of assembling and using same

Abstract

A diesel engine exhaust pipe clamp with critical cone angle limitation and elastic compensation functions is used to connect the exhaust pipe and the bellows. The clamp includes a two-part clamp, bolts, nuts, washers, and locking washers. The inner wall of the clamp has a truncated conical groove with a cone angle of 20°±0.25°, consistent with the cone angle of the outer wall of the pipe. The top inner wall of the clamp forms a surface contact seal with the outer wall of the pipe. When the bolt is tightened, the clamp undergoes radial elastic deformation to compensate for machining and assembly gaps, ensuring uniform distribution of contact clamping force. The locking washers are bent and pressed tightly against the side plane of the nut to form a mechanical locking anti-loosening mechanism. This invention achieves reliable sealing and anti-loosening while reducing machining accuracy requirements through the synergistic effect of precise cone angle limitation and elastic deformation compensation, making it suitable for diesel engine exhaust systems.

Description

Technical Field

[0001] This invention relates to the field of diesel engine assembly technology, and in particular to a diesel engine exhaust pipe clamp with critical cone angle limitation and elastic compensation functions, its assembly method and application. Background Technology

[0002] During diesel engine operation, the sealing performance of the connection between the exhaust pipe and the bellows is one of the key factors affecting the overall power, reliability, and safety of the engine. As an important fastener connecting the exhaust pipe and the bellows, the design of the clamp directly determines whether the two pipes can achieve a proper sealing connection. Tightening the exhaust pipe and bellows with clamps effectively ensures the connection status of the two pipes and prevents leakage of high-temperature exhaust gases.

[0003] Currently, to ensure a tight fit between the inner side of the clamp and the exhaust pipe and bellows, the common practice is to make the inner arc of the clamp form a line contact with the outer contour of the exhaust pipe and bellows. However, this line contact method requires high machining precision for the clamp; any deviation in machining can lead to the risk of air leakage. Furthermore, diesel engines are subjected to high temperatures, high pressures, and severe vibrations during operation, making the clamp connection prone to loosening of bolts and nuts due to vibration, resulting in insufficient tightening force and seal failure.

[0004] Therefore, there is an urgent need to design an exhaust pipe clamp that is simple in structure, easy to process, has good anti-loosening effect, and can effectively reduce the risk of air leakage, so as to ensure the long-term safe and stable operation of the diesel engine exhaust system. Summary of the Invention

[0005] This invention addresses the technical problems of existing diesel engine exhaust pipe clamps, such as high machining precision requirements, easy loosening under vibration, and sealing failure due to high-temperature thermal deformation. It provides a diesel engine exhaust pipe clamp with critical cone angle limitation and elastic compensation functions, along with its assembly method and application. Through the precise limitation of the cone surface contact angle and the synergistic effect of the clamp's elastic deformation compensation mechanism, reliable sealing of the exhaust pipe and bellows connection interface is maintained while reducing machining precision requirements (i.e., reducing manufacturing costs). Simultaneously, a mechanical locking structure ensures the clamp's anti-loosening performance under long-term vibration conditions.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: On one hand, the present invention provides a diesel engine exhaust pipe clamp with critical cone angle limitation and elastic compensation functions for connecting the exhaust pipe and the bellows, the clamp comprising: A two-part clamp is provided at both ends of the two-part clamp, which is fitted around the outer periphery of the connection end between the exhaust pipe and the corrugated pipe. The two-part clamp is provided with connecting lugs at both ends, and the connecting lugs are provided with through holes for bolts to pass through. Bolts and nuts, wherein the bolts pass through through holes in the two connecting lugs and are threadedly connected to the nuts; A washer is disposed between the head of the bolt and the connecting lug. And a retaining washer, disposed between the nut and the connecting lug; The inner wall of the two-half clamp is provided with a truncated conical groove. The cone angle of the truncated conical groove is 20°±0.25°, which is consistent with the cone angle of the outer wall of the exhaust pipe and the corrugated pipe connection end. The top inner wall of the cone surface of the truncated conical groove is used to form a surface contact sealing fit with the top outer wall of the two pipe connection ends. The two-half clamp is configured such that when the bolt and nut are subjected to a preset axial preload, the two-half clamp generates radial elastic deformation. The elastic deformation is used to compensate for the machining and assembly gap between the truncated conical groove and the outer wall of the pipeline, so as to ensure that the clamping force of the surface contact sealing fit is evenly distributed. The stop washer is a metal elastic washer with a bendable stop lug. After the nut is tightened, the stop lug of the stop washer bends and fits tightly against the side plane of the nut, forming a mechanical lock to restrict the circumferential rotation of the nut.

[0007] Preferably, the cone angle of the truncated conical groove is selected as 20°±0.25° because: when the cone angle is less than 15°, the axial preload of the bolt is converted into an excessive axial component of the bellows, which can easily lead to excessive axial compression and failure of the bellows; when the cone angle is greater than 25°, the axial preload is converted into a insufficient radial component, which is not enough to eliminate the machining and assembly gap; only within the range of 20°±0.25° can the clamp generate sufficient radial clamping force to achieve the surface contact seal while ensuring the safe axial deformation of the bellows.

[0008] Preferably, the main body of the retaining washer has a central hole through which the bolt passes, and the retaining lug is at least one tongue extending outward from the edge of the main body. After the nut is tightened, the tongue is bent and deformed to fit against the outer wall of the nut.

[0009] Preferably, the two-part clamp includes an upper clamping flap and a lower clamping flap, with the two ends of the upper clamping flap and the lower clamping flap extending outward to form the connecting lugs, and the connecting lugs having flat end faces that fit together.

[0010] Preferably, the washer is fitted onto the bolt shank and abuts against the head of the bolt and the connecting lug, thereby increasing the bearing area between the bolt head and the connecting lug.

[0011] Preferably, the material of the two-part clamp is heat-resistant stainless steel, and the strength grade of the bolt and the nut is grade 8.8 or 10.9, and the surface is coated with a high-temperature resistant anti-seize lubricating coating.

[0012] In another aspect, the present invention also provides a method for assembling a diesel engine exhaust pipe clamp, comprising the following steps: The first step is to attach the connecting end of the bellows to the connecting end of the exhaust pipe and align the interfaces. The second step is to align the truncated conical grooves of the two halves of the clamp with the outer conical surfaces of the exhaust pipe and the corrugated pipe connection ends respectively and close them, so that the top inner wall of the truncated conical groove forms a surface contact with the outer walls of the two pipes. The third step is to put a washer on the outside of the connecting lug at one end of the two halves of the clamp, and then insert the bolt through the washer and through the connecting lug at both ends. Fourth step, a stop washer is fitted onto one end of the connecting lug where the bolt protrudes, and a nut is screwed on. The fifth step is to use a torque wrench to tighten the nut symmetrically in stages to a preset torque value (preferably 80 N·m to 120 N·m), so that the two halves of the clamp will produce radial elastic deformation to compensate for the machining and assembly gap between the truncated conical groove and the outer wall of the pipeline, and to make the two halves of the clamp hold the two pipelines tightly. Step 6: Bend the locking lug of the locking washer so that it fits tightly against the side plane of the nut to complete the mechanical anti-loosening locking.

[0013] Third, the present invention also provides a diesel engine exhaust pipe connection structure, including an exhaust pipe, a corrugated pipe and a diesel engine exhaust pipe clamp as described above, wherein the connection ends of the exhaust pipe and the corrugated pipe are fastened together by the clamp, and the inner wall of the top of the truncated conical groove of the clamp forms a surface contact seal with the outer wall of the exhaust pipe and the corrugated pipe.

[0014] Fourth, the present invention also provides a diesel engine, including the diesel engine exhaust pipe connection structure as described above.

[0015] Compared with the prior art, the present invention has the following advantages: 1) By designing the inner wall of the clamp as a truncated conical groove and using the bolt preload to cause radial elastic deformation of the clamp to compensate for the machining and assembly gap, the machining accuracy of the clamp can be reduced from IT6 level required by the existing technology to IT8 level. Without adding any additional sealing elements, high reliability sealing is achieved by relying on the mechanical properties of the structure itself, which significantly reduces the processing cost and scrap rate.

[0016] 2) A dual anti-loosening mechanism is adopted, consisting of "pre-tightening force elastic deformation clamping + mechanical bending locking of the locking washer". On the one hand, the clamp relies on the radial elastic deformation generated by the pre-tightening force to continuously provide clamping force; on the other hand, the locking washer forms an irreversible mechanical lock by bending and pressing against the side plane of the nut, effectively resisting the adverse effects of high-frequency and wide-amplitude vibration of the diesel engine on the connection reliability and eliminating the risk of seal failure caused by nut loosening.

[0017] 3) The surface contact sealing fit of the present invention greatly increases the contact area. Under the same pre-tightening force, the contact stress distribution is more uniform, and there is no local stress concentration or contact blind zone. This fundamentally reduces the probability of high-temperature exhaust gas leakage and improves the safety and environmental performance of the exhaust system.

[0018] 4) The clamp of the present invention consists of only five basic parts: clamp, bolt, nut, washer and stop washer. There is no need to add complex mechanisms. The number of parts is small, the assembly steps are clear, the skill requirements of the operators are low, and it has good industrial applicability and promotion value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the diesel engine exhaust pipe clamp of the present invention; Figure 2 This is a schematic diagram of the clamp structure in this invention; where a is a side view, b is a sectional view AA, c is a top view, and d is a sectional view BB. Figure 3 This is an assembly diagram of the diesel engine exhaust pipe clamp of the present invention; In the picture: 1-Clamping clamp, 2-Stop washer, 3-Bolt, 4-Type I nut, 5-Washer. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] See Figure 1 , Figure 1 This is a schematic diagram of the structure of a diesel engine exhaust pipe clamp according to the present invention, used at the connection between the diesel engine exhaust pipe and the corrugated pipe, as shown in the figure, including clamp 1, stop washer 2, bolt 3, type I nut 4 and washer 5.

[0022] In this embodiment, the clamp 1 adopts a split-type structure, consisting of an upper clamp flap and a lower clamp flap. During assembly, the upper and lower clamp flaps are joined together from the upper and lower sides of the connection end of the exhaust pipe and the bellows, respectively, so that the inner walls of the two halves of the clamp tightly cover the outer circumferential surfaces of the two pipe ends. Both ends of the clamp 1 (i.e., the free ends of the upper and lower clamp flaps) are respectively provided with outwardly extending connecting lugs, and the lugs have through holes for bolts to pass through.

[0023] During assembly, the bolt 3 passes through the through hole on one side of the lug seat, through the washer 5, and then through the through hole on the other side of the lug seat and through the locking washer 2. Finally, it is threaded and locked by the I-type nut 4. Specifically, the washer 5 is placed between the head of the bolt 3 and the clamp lug seat to increase the contact area and reduce wear; the locking washer 2 is placed between the I-type nut 4 and the clamp lug seat to prevent the nut from rotating and loosening under the high-frequency vibration of the diesel engine.

[0024] See Figure 2 , Figure 2 This is a schematic diagram of the clamp structure in this invention. The internal groove in the middle of the clamp 1 is designed as an arc shape (i.e., an arc groove). The radius of curvature and contour shape of the arc groove are adapted to the outer contour shape of the exhaust pipe and the corrugated pipe connection end, and the apex angle (i.e., the included angle of the cone surface) of the two are the same.

[0025] In this embodiment, by controlling the machining tolerance of the arc-shaped groove within a reasonable range, it is ensured that when the two halves of the clamp are tightened, the top inner wall of the arc-shaped groove of the clamp makes surface contact with the top outer wall of the exhaust pipe and the corrugated pipe, rather than the line contact as in the prior art. Adopting a surface contact method significantly reduces the stringent requirements for the machining accuracy of the inner arc of the clamp, thus lowering manufacturing costs. Furthermore, surface contact increases the contact area, effectively reducing contact stress under the same preload, and forming a uniform clamping force distribution at the interface between the two pipes, thereby greatly reducing the risk of high-temperature exhaust gas leakage from the connection gap.

[0026] See Figure 3 , Figure 3 This is a schematic diagram of the assembly of the diesel engine exhaust pipe clamp of the present invention. To achieve the precise fit of the aforementioned surface contact, the part of the exhaust manifold that mates with the clamp is designed with a conical surface structure. Preferably, the included angle of the conical surface of this mating part is set to 20°±0.25°. Correspondingly, the inner wall taper of the clamp's arc-shaped groove matches this included angle. The selection of this angle range ensures reliable axial positioning of the clamp, preventing the clamp from moving axially along the pipe wall, and also allows the clamp to generate a radial component force during bolt tightening, clamping the ends of the two pipes towards the central axis, further enhancing the sealing effect.

[0027] Please continue reading. Figure 1As a preferred embodiment of the present invention, the locking washer 2 is a metal elastic washer with a specific bending structure. When the operator tightens the type I nut 4 to a predetermined torque value (for example, 80~120 N·m depending on the bolt specification, depending on the machine model), the elastic tongue of the locking washer 2 undergoes elastic deformation under the compression of the nut, generating a reverse frictional force and gripping the outer hexagonal side of the nut.

[0028] Under the high-frequency, wide-amplitude vibration conditions generated by the long-term high-load operation of the diesel engine, the stop washer 2 can continuously provide a stable damping torque, effectively preventing the I-type nut 4 from rotating loose relative to the bolt 3 in the circumferential direction, thereby ensuring that the clamp maintains the set preload for a long time, and ensuring the long-term reliability and sealing durability of the connection between the exhaust pipe and the bellows.

[0029] The specific assembly steps for this clamp assembly are as follows: First, attach one end of the corrugated pipe to the connection end of the exhaust pipe, and adjust the position of the two pipe interfaces to ensure that the interfaces are aligned. The second step is to align the inner arc groove of the two-half clamp 1 with the outer conical surface of the connection end of the exhaust pipe and the bellows, and close the two-half clamp. The third step is to put the washer 5 on the outside of one ear seat in sequence, and insert the bolt 3 from the washer side and through the through hole of both ear seats. Fourth step, insert the locking washer 2 into the end of the bolt 3 that protrudes from the other side of the lug, and screw on the I-nut 4; Fifth step, use a torque wrench to tighten the I-nut 4 symmetrically and in stages until the preset torque value is reached, ensuring that the two halves of the clamp completely grip the two pipes; Step 6: After tightening, use a special tool to bend the locking lug of the locking washer 2 so that it fits tightly against the side plane of the I-type nut 4 to complete the mechanical locking and anti-loosening.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A diesel exhaust pipe clamp having a taper angle critical limit and elastic compensation function for connecting an exhaust pipe and a bellows, characterized by, include: Two-half clamp (1), the two-half clamp (1) hugs the outer periphery of the connection end of the exhaust pipe and the corrugated pipe, and the two ends of the two-half clamp (1) are respectively provided with connecting lugs, and the connecting lugs are provided with through holes for bolts to pass through. Bolt (3) and nut (4), wherein the bolt (3) passes through the through holes on the two connecting lugs and is threaded to the nut (4); Washer (5) is disposed between the head of the bolt (3) and the connecting lug; And a stop washer (2), which is disposed between the nut (4) and the connecting lug; The inner wall of the two-half clamp (1) is provided with a truncated conical groove. The cone angle of the truncated conical groove is 20°±0.25°, which is consistent with the cone angle of the outer wall of the exhaust pipe and the corrugated pipe connection end. The inner wall of the top of the cone surface of the truncated conical groove is used to form a surface contact sealing fit with the top outer wall of the two pipe connection ends. When the bolt (3) and nut (4) apply a preset axial preload, the two-half clamp (1) generates radial elastic deformation. The elastic deformation is used to compensate for the processing and assembly gap between the truncated conical groove and the outer wall of the pipe, so as to ensure that the clamping force of the surface contact sealing fit is evenly distributed. The stop washer (2) is a metal elastic washer with a bendable stop ear. After the nut (4) is tightened, the stop ear of the stop washer (2) bends and sticks to the side plane of the nut (4) to form a mechanical lock to restrict the circumferential rotation of the nut (4).

2. The diesel exhaust pipe clamp of claim 1, wherein, The main body of the stop washer (2) has a central hole through which the bolt (3) passes. The stop ear is at least one tongue extending outward from the edge of the main body. After the nut (4) is tightened, the tongue is bent and deformed to fit against the outer wall of the nut (4).

3. The diesel exhaust pipe clamp of claim 1, wherein, The two-half clamp (1) includes an upper clamping flap and a lower clamping flap. The two ends of the upper clamping flap and the lower clamping flap extend outward to form the connecting ear seat. The connecting ear seat has flat end faces that fit together.

4. The diesel engine exhaust pipe clamp according to claim 1, characterized in that, The washer (5) is fitted onto the thread of the bolt (3) and abuts against the head of the bolt (3) and the connecting lug, thereby increasing the bearing area between the head of the bolt (3) and the connecting lug.

5. A method of assembling a diesel exhaust pipe clamp, characterized by, The method for assembling a diesel engine exhaust pipe clamp as described in any one of claims 1 to 6 includes the following steps: fitting the connecting end of the corrugated pipe onto the connecting end of the exhaust pipe and aligning the interfaces; Align the truncated conical grooves of the two halves of the clamp (1) with the outer conical surfaces of the exhaust pipe and the corrugated pipe connection ends respectively and close them so that the top inner wall of the truncated conical groove forms a surface contact with the outer walls of the two pipes. A washer (5) is fitted on the outside of the connecting lug at one end of the two halves of the clamp (1), and the bolt (3) is inserted from the side of the washer (5) and passes through the connecting lug at both ends; A stop washer (2) is fitted onto one end of the connecting lug through which the bolt (3) protrudes, and a nut (4) is screwed on. The nut (4) is tightened symmetrically in stages to a preset torque value using a torque wrench, so that the two-half clamp (1) produces radial elastic deformation to compensate for the processing and assembly gap between the truncated conical groove and the outer wall of the pipeline, and so that the two-half clamp (1) hugs the two pipelines tightly. The locking lug of the locking washer (2) is bent so that it fits tightly against the side plane of the nut (4) to complete the mechanical anti-loosening locking.

6. A diesel exhaust pipe connection structure characterized by comprising: The device includes an exhaust pipe, a bellows, and a diesel engine exhaust pipe clamp as described in any one of claims 1 to 5, wherein the connecting ends of the exhaust pipe and the bellows are fastened together by the clamp, and the inner wall of the top of the truncated conical groove of the clamp forms a surface contact seal with the outer wall of the exhaust pipe and the bellows.

7. A diesel engine characterized by comprising: The diesel engine includes the diesel engine exhaust pipe connection structure as described in claim 6.

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