Anti-loose pipe joint

Abstract

The utility model discloses an anti-loose pipe joint which is used on hydraulic or other oil way pipeline joint assemblies and comprises a joint body, a cutting sleeve nut, an oil pipe and a cutting sleeve, the oil pipe is inserted at one end of the joint body, the cutting sleeve nut and the cutting sleeve are sleeved on the oil pipe, the cutting sleeve nut is connected with the joint body through a thread structure, and the cutting sleeve nut is connected with the joint body through a thread structure. The clamping sleeve is tightly pressed between the inner diameter sealing face of the connector body and an oil pipe, the external thread on the connector body is a common triangular thread, the internal thread on the clamping sleeve nut is an anti-loosening thread, the internal thread of the clamping sleeve nut is of an anti-loosening thread structure, the anti-vibration and anti-loosening performance of threaded connection of the pipe connector is improved, and the anti-loosening performance of the pipe connector is improved. The problems of thread loosening and material fatigue damage of the hydraulic pipeline joint are solved.

Description

Technical Field

[0001] The utility model relates to the field of hydraulic oil circuit and gear oil circuit pipeline joints, in particular to an anti-loosening pipe joint. Background Art

[0002] As an indispensable component of the hydraulic system, the pipe joint plays a vital role in achieving the normal operation of the hydraulic system and its gear oil circuit and other systems. At present, the pipe joints are mainly divided into two types: nut sleeve structure and cone hose structure, both of which are conventional triangular internal and external thread connection structures. The application conditions of engineering machinery are relatively harsh, the hydraulic system oil pressure is large, accompanied by pressure oil impact and large vibration of the body, and most of them are alternating loads. Under the action of variable loads, the contact surface of the threaded connection has local slippage or even rotational loosening, accompanied by pipeline noise and oil leakage. This failure is usually caused by the loosening of the threaded connection itself and fatigue damage of the material. Studies have shown that there is a lateral gap when the traditional ordinary triangular thread connection is tightened. When vibrating, it will loosen due to the existence of the thread lead angle; when the traditional thread is locked, more than 80% of the load often acts on the first two teeth of the locking surface. Load imbalance is also the main cause of fatigue damage to the pipe joint material.

[0003] At present, the solutions to the loosening of threaded connections of hydraulic system pipe joints are: the method of applying sealant and thread locker is mostly adopted; in addition, there are new structure anti-loosening pipe joints that prevent and prevent the pipe joints from rotating and loosening by adding additional locking screws and limit blocks, thereby achieving the anti-loosening effect. The above methods are complex in structure, high in cost, and difficult to implement and promote. Utility Model Content

[0004] In view of the problems existing in the above-mentioned prior art, the utility model provides an anti-loosening pipe joint, in which the internal thread of the ferrule nut is set as an anti-loosening thread structure, thereby improving the vibration and anti-loosening performance of the pipe joint threaded connection, and solving the problems of thread loosening and material fatigue damage in hydraulic pipeline pipe joints.

[0005] The anti-loosening thread structure is a wedge-shaped inclined surface anti-loosening internal thread or an R-type arc surface anti-loosening internal thread.

[0006] The wedge-shaped bevel anti-loosening internal thread has a unique wedge-shaped bevel at the root of the thread, which is generally 30 degrees. When the bolt and nut are tightened against each other, the tip of the bolt is tightly pressed against the wedge-shaped bevel of the Spirax thread, thereby generating a large radial clamping force and making the thread load distribution more even.

[0007] The R-type arc surface anti-loosening internal thread is designed with an R-type arc surface at the bottom of the thread. When the external thread fastener and the R-type thread fastener are pre-tightened against each other, the tooth tip of the external thread fastener is slightly retracted and pressed against the R-type surface, which can effectively protect the tooth tip of the external thread. The R-type design makes the stress distribution when the fastener is connected more reasonable, and the force on each tooth is more stable.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a kind of anti-loosening pipe joint, which is used for hydraulic or other oil pipeline joint assemblies. The anti-loosening pipe joint includes: a joint body, a ferrule nut, an oil pipe, and a ferrule. The oil pipe is inserted at one end of the joint body, the ferrule nut and the ferrule are sleeved on the oil pipe, the ferrule nut is connected to the joint body through a threaded structure, and the ferrule is pressed between the inner diameter sealing surface of the joint body and the oil pipe. The external thread on the joint body is an ordinary triangular thread, and the internal thread on the ferrule nut is an anti-loosening thread.

[0009] Furthermore, the inner diameter sealing surface of the joint body is a conical surface, and the contact surface between the ferrule and the inner diameter sealing surface of the joint body is a conical surface.

[0010] Furthermore, the anti-loosening thread of the ferrule nut is a wedge-shaped inclined surface anti-loosening internal thread structure, and a wedge-shaped inclined surface is arranged at the root of the inner tooth tip of the internal thread, that is, on the major diameter.

[0011] Furthermore, the anti-loosening thread of the ferrule nut is an R-shaped arc surface anti-loosening internal thread structure, and an R-shaped arc surface is set at the root of the inner tooth tip of the internal thread, that is, on the major diameter, and the R-shaped arc surface is recessed in the direction away from the tooth top.

[0012] Furthermore, the end of the oil pipe inserted in the joint body is provided with a chamfer.

[0013] The beneficial effect of the utility model is that the internal thread of the ferrule nut is set as an anti-loosening thread structure, so that the vibration-proof and anti-loosening performance and fatigue strength of the pipe joint thread connection pair are improved when it is matched with the ordinary triangular external thread of the joint body, making the connection more stable and firm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the utility model;

[0015] Figure 2 for Figure 1 A schematic cross-sectional structure diagram of ;

[0016] Figure 3 It is a schematic cross-sectional diagram of the internal thread structure of the wedge-shaped surface of the ferrule nut;

[0017] Figure 4 This is a schematic cross-sectional diagram of the R-shaped arc surface internal thread structure of the ferrule nut;

[0018] Figure 5Schematic diagram of the force analysis structure of the internal thread on the wedge surface of the ferrule nut and the external thread on the connector;

[0019] Figure 6 Schematic diagram of the force analysis structure of the R-shaped arc surface internal thread of the ferrule nut and the external thread of the joint;

[0020] Figure 7 This is a schematic diagram of the force analysis structure of the conventional ferrule nut and the joint body using a common thread structure;

[0021] In the figure: 1. Connector body; 2. Ferrule nut; 2-1. Wedge-shaped inclined surface anti-loosening internal thread; 2-2. R-shaped arc surface anti-loosening internal thread; 3. Oil pipe; 4. Ferrule; 5-1. Ordinary internal thread. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the scope of the utility model.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] like Figure 1-2 As shown, a kind of anti-loosening pipe joint is used for hydraulic or other oil pipeline joint assemblies, and the anti-loosening pipe joint includes: a joint body 1, a ferrule nut 2, an oil pipe 3, and a ferrule 4. The oil pipe 3 is inserted at one end of the joint body 1, and the ferrule nut 2 and the ferrule 4 are sleeved on the oil pipe 3. The ferrule nut 2 and the joint body 1 are connected through a threaded structure, and the ferrule 4 is pressed between the inner diameter sealing surface of the joint body 1 and the oil pipe 3 to achieve a pipeline sealing effect. The external thread on the joint body 1 is an ordinary triangular thread, and the internal thread on the ferrule nut 2 is an anti-loosening thread. The external thread on the joint body 1 matches the internal thread of the ferrule nut 2, and the pitch, number of threads, and helix angle of the two are equal.

[0025] like Figure 7 As shown, the internal thread of the ferrule nut 2 and the external thread of the joint body 1 in the prior art are both ordinary triangular threads. When the pipe joint is tightened, the internal thread of the ferrule nut 2 is pressed and fitted with the external thread of the joint body 1. A force analysis is performed on the external thread of the joint body 1, and the positive pressure FN perpendicular to the internal thread of the ferrule nut 2 is decomposed into an axial force Fa and a clamping force F1 perpendicular to the axis of the joint body 1.

[0026] like Figure 2As shown, the inner diameter sealing surface of the joint body 1 is a conical surface, and the contact surface between the ferrule 4 and the inner diameter sealing surface of the joint body 1 is a conical surface, which improves the sealing effect.

[0027] like Figure 3 As shown, the anti-loosening thread of the ferrule nut 2 is a wedge-shaped inclined surface anti-loosening internal thread 2-1 structure, and a wedge-shaped inclined surface is set at the root of the inner tooth tip of the internal thread, i.e., on the major diameter, as shown in FIG. Figure 5 As shown, the force analysis of the external thread of the joint body 1 is carried out, and it is subjected to a positive pressure FN perpendicular to the wedge-shaped inclined surface, an axial force Fa, and a clamping force F1 perpendicular to the axis of the joint body 1. The external thread of the joint body 1 is an ordinary triangular thread. When it is matched with the internal thread of the ferrule nut 2, the wedge-shaped inclined surface will be tightly pressed against the tooth tip of the triangular external thread of the joint body 1, thereby generating a large clamping force F1, which is about 3 times that of an ordinary thread; and the tooth tip is easily deformed when in contact, so that the load is evenly distributed on the entire length of the contacting thread spiral line, avoiding the situation that more than 80% of the load is concentrated on the thread surface of the first and second teeth when the ordinary thread is engaged. This structure solves the problem of lateral clearance and uneven load distribution when the threaded connection pair is matched, thereby improving the anti-loosening performance of the pipe joint.

[0028] like Figure 4 As shown, the anti-loosening thread of the ferrule nut 2 is an R-shaped arc surface anti-loosening internal thread 2-2 structure, and an R-shaped arc surface is set on the root of the inner tooth tip of the internal thread, that is, on the major diameter, and the R-shaped arc surface is concave in the direction away from the tooth top; Figure 6 As shown, the force analysis of the external thread of the joint body 1 is carried out, and it is subjected to a positive pressure FN perpendicular to the R-shaped arc surface, an axial force Fa, and a clamping force F1 perpendicular to the axis of the joint body 1. The external thread of the joint body 1 is an ordinary triangular thread. When it is matched with the internal thread of the ferrule nut 2, the R-shaped arc surface will be tightly pressed against the tooth tip of the triangular external thread of the joint body 1, thereby generating a large clamping force F1, which is about 3 times that of an ordinary thread; and the tooth tip is easily deformed when in contact, so that the load is evenly distributed on the entire length of the contacting thread spiral line, avoiding the situation that more than 80% of the load is concentrated on the thread surface of the first and second teeth when the ordinary thread is engaged; this structure solves the problem of lateral clearance and uneven load distribution during the matching of the threaded connection pair, thereby improving the anti-loosening performance of the pipe joint.

[0029] like Figure 2 As shown, the end of the oil pipe 3 inserted in the joint body 1 is provided with a chamfer, which on the one hand prevents the inner diameter sealing surface of the joint body 1 from being scratched and ensures the sealing effect, and on the other hand can reduce the gap between the end of the oil pipe 3 and the inner diameter sealing surface of the joint body 1, further improving the sealing effect. The preferred slope of the chamfer is ±0.5-1° of the slope of the inner diameter sealing surface.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A loose-proof pipe joint, used in hydraulic or other oil pipeline joint assemblies, characterized in that: The anti-loosening pipe joint comprises: a joint body (1), a ferrule nut (2), an oil pipe (3), and a ferrule (4). The oil pipe (3) is inserted into one end of the joint body (1), the ferrule nut (2) and the ferrule (4) are sleeved on the oil pipe (3), the ferrule nut (2) and the joint body (1) are connected via a threaded structure, and the ferrule (4) is pressed between the inner diameter sealing surface of the joint body (1) and the oil pipe (3). The external thread on the joint body (1) is a common triangular thread, and the internal thread on the ferrule nut (2) is an anti-loosening thread.

2. The anti-loosening pipe joint according to claim 1, characterized in that: The inner diameter sealing surface of the joint body (1) is a conical surface, and the contact surface between the ferrule (4) and the inner diameter sealing surface of the joint body (1) is a conical surface.

3. The anti-loosening pipe joint according to claim 1, characterized in that: The anti-loosening thread of the ferrule nut (2) is a wedge-shaped inclined surface anti-loosening internal thread structure (2-1), and a wedge-shaped inclined surface is provided at the root of the inner tooth tip of the internal thread, i.e., on the major diameter.

4. The anti-loosening pipe joint according to claim 1, characterized in that: The anti-loosening thread of the ferrule nut (2) is an R-shaped arc surface anti-loosening internal thread structure (2-2), wherein an R-shaped arc surface is provided at the root of the inner tooth tip of the internal thread, i.e., on the major diameter, and the R-shaped arc surface is recessed in a direction away from the tooth top.

5. The anti-loosening pipe joint according to claim 1, characterized in that: The ferrule (4) is rigidly connected to the oil pipe (3).

6. The anti-loosening pipe joint according to claim 1, characterized in that: The end of the oil pipe (3) inserted into the joint body (1) is provided with a chamfer.

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