Anti-back hydraulic nut

Abstract

The utility model discloses an anti-retreating hydraulic nut which comprises a hydraulic cylinder, a piston and a locking nut, an oil cavity of the hydraulic cylinder is connected with an external pump station through a flow channel, the piston is located in the oil cavity of the hydraulic cylinder and connected with the hydraulic cylinder in a sliding mode, the piston is of an annular structure and provided with an internal thread and an external thread, and the piston is connected with a bolt through the internal thread. The piston is connected with the locking nut through an external thread, and the thread used for connecting the locking nut and the piston is a sawtooth thread. According to the anti-retreating hydraulic nut, the threads used for connecting the locking nut and the piston are arranged to be the sawtooth threads, friction force can be generated between the sawtooth shape and the surface of a matching piece, and therefore the firmness and sealing performance of the threads are improved, and the sawtooth threads can prevent loosening or falling off; the service life of the threads is prolonged, the stability of the threads is improved, thread teeth of the sawtooth threads are not prone to deformation, the gap between the inner threads and the outer threads after meshing is smaller, and therefore the anti-retreating effect and the pre-tightening effect are good.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of hydraulic nut, especially to a kind of anti-retreating hydraulic nut. BACKGROUND

[0002] Hydraulic nut is used for the bolt that needs to be frequently disassembled;The pre-tightening of oversized bolt;Locking of large workpiece and other occasions.For example: nuclear power engineering.Its principle is to use ultra-high pressure oil to generate a thrust on the shaft and a tension on the shaft sleeve, so that the shaft and the shaft sleeve are evenly connected under stress.

[0003] Due to the compact working condition of nuclear power engineering, the space is limited, if mechanical nut is used, the disassembly and installation of nut will require a large space, which will lead to pre-tightening difficulty, so hydraulic nut is more suitable.Nuclear power engineering works in high temperature environment and generates vibration during work, so the nut used for connection is prone to looseness, and based on the particularity of nuclear power engineering, radiation often exists, therefore, nuclear power engineering cannot be frequently overhauled, which will affect the health of workers, so the hydraulic nut needs to have good thermal stability and good sealing to ensure that the hydraulic nut works for 50 years.

[0004] The hydraulic nut mainly consists of three parts, including hydraulic cylinder, piston and locking nut, the piston is located in the hydraulic cylinder and is in sliding connection with the hydraulic cylinder, the piston is provided with internal thread and external thread, the internal thread is connected with the bolt, and the external thread is connected with the locking nut.The operation steps of hydraulic nut are as follows:

[0005] Step 1: use ultra-high pressure oil to push the piston in the hydraulic cylinder to directly apply external force to the bolt, so that the bolt under the applied force is stretched in its elastic deformation zone;

[0006] Step 2: after the bolt is stretched, the locking nut is tightened, so that the bolt is locked in the stretched position by the locking nut, and then the hydraulic cylinder is depressurized, and the hydraulic oil flows back to the pump station.

[0007] In the actual use process of hydraulic nut, there is a gap between the thread connection part of the locking nut and the piston.

[0008] In the above step 1, the bolt will be stretched to a length that just meets the pre-tightening force, when the hydraulic cylinder is depressurized, due to the negative pressure state of the hydraulic cylinder and the gap between the locking nut and the piston, the stretched bolt will shrink, resulting in that the actual pre-tightening force is less than the preset pre-tightening force, the locking precision is reduced, and the locking is unreliable. SUMMARY

[0009] The utility model aims at the basis of improving the locking precision of hydraulic nut assembly bolt and preventing pressure relief and back-off demand on the basis of existing hydraulic nut, and constructs a kind of anti-retreating hydraulic nut.

[0010] The anti-back hydraulic nut comprises a hydraulic cylinder, a piston and a locking nut, an oil cavity of the hydraulic cylinder is connected with an external pump station through a flow channel, the piston is located in the oil cavity of the hydraulic cylinder and is in sliding connection with the hydraulic cylinder, the piston is in annular structure and is provided with an inner thread and an outer thread, the piston is connected with a bolt through the inner thread, and the piston is connected with the locking nut through the outer thread, characterized in that the thread for connecting the locking nut and the piston is a sawtooth thread.

[0011] When the sawtooth thread rotates, the sawtooth shape can generate friction with the surface of the cooperating part, thereby increasing the firmness and sealing performance of the thread. In addition, the sawtooth thread can prevent loosening or falling off, thereby improving the service life and stability of the thread.

[0012] In general, a pipe thread is often used for connection in a hydraulic nut, and the thread of the pipe thread is more prone to deformation than the thread of the sawtooth thread, and the gap between the inner and outer threads after engagement is also larger. Therefore, the sawtooth thread has a better anti-back effect and a good pre-tightening effect when the hydraulic nut is depressurized.

[0013] Further, the thread of the sawtooth thread comprises a first thread surface and a second thread surface, the first thread surface forms a 7° angle with a rotation axis, the second thread surface forms a 45° angle with the rotation axis, and the rotation axis refers to a straight line where the rotation axis of the locking nut is located. Compared with the first thread surface forming a 3° angle with the rotation axis and the second thread surface forming a 30° angle with the rotation axis according to the national standard, the connection strength is better and the anti-back effect is better.

[0014] Further, the first thread surface provided on the locking nut is opposite to the first thread surface provided on the piston and abuts against each other when the hydraulic nut is depressurized. Further, the hydraulic cylinder is provided with an oil cavity and a linkage cavity, the oil cavity is in communication with the linkage cavity, the oil cavity is located above the linkage cavity, and the diameter of the oil cavity is larger than the diameter of the linkage cavity.

[0015] Further, the piston comprises an upper part and a lower part, the diameter of the upper part is larger than the diameter of the lower part, the outer side of the upper part is provided with a sliding member, the sliding member is in sliding connection with the inner wall of the oil cavity, the outer thread of the piston is provided on the outer side of the upper part, the outer thread of the piston is located above the sliding member, and the lower part is in sliding connection with the linkage cavity.

[0016] The middle part of the piston is provided with a connecting hole penetrating upward and downward, the inner thread is provided on the hole wall of the connecting hole, and the diameter of the connecting hole is equal to the diameter of the bolt.

[0017] The piston is provided with a groove, and the groove is in communication with the flow channel.

[0018] Further, the lower part of the sliding piece is provided with a sealing piece, which is a V-shaped spring energy ring.

[0019] Further, the locking nut is provided with a plurality of connecting holes for connecting a screwing tool.

[0020] Further, the hydraulic nut is made of non-magnetic material, which can ensure the mechanical properties of the hydraulic nut.

[0021] The anti-back hydraulic nut has the advantages that the thread for connecting the locking nut and the piston is provided as a sawtooth thread, the sawtooth shape can generate friction with the surface of the cooperating piece during rotation, thereby increasing the firmness and sealing property of the thread, the sawtooth thread can prevent loosening or falling off, the service life and stability of the thread are improved, the thread tooth of the sawtooth thread is not prone to deformation, the gap between the inner and outer threads after meshing is smaller, the sawtooth thread has good anti-back effect during pressure relief of the hydraulic nut, and the pre-tightening effect is good.

[0022] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, which can be implemented according to the content of the specification, and in order to let the above and other purposes, characteristics and advantages of the utility model can be more obvious and easy to understand, the following preferred embodiments are described in detail, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained without creative labor according to these drawings;

[0024] Figure 1 It is the overall structure schematic diagram of a specific example of the hydraulic nut of the utility model;

[0025] Figure 2 It is the sectional structure schematic diagram of the hydraulic nut; Figure 1

[0026] Figure 3 It is the structure schematic diagram of the hydraulic cylinder in a specific example of the hydraulic nut of the utility model;

[0027] Figure 4 It is the enlarged view of the structure at A in the hydraulic nut; Figure 2

[0028] ​​Figure 5 is a specific example of the utility model hydraulic nut structure diagram of locking nut;

[0029] In the figure: 102, hydraulic cylinder; 103, interface; 104, piston; 105, locking nut; 106, connecting hole; 109, linkage cavity; 110, flow channel; 111, oil cavity; 115, sliding element; 117, connecting hole; 120, annular groove; 121, V-shaped spring energy storage ring. DETAILED DESCRIPTION

[0030] In order to make the technical problem, technical scheme and beneficial effect of the utility model more clearly understood, the utility model is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model and not to limit the utility model.

[0031] The utility model is further described in combination with the drawings.

[0032] As shown in Figure 1 and Figure 2 , the hydraulic nut described in the embodiment is made of non-magnetic material, and the hydraulic nut comprises a hydraulic cylinder 102, a piston 104 and a locking nut 105, the hydraulic cylinder 102 is connected with a hydraulic oil interface 103, and the hydraulic cylinder 102 is connected with an external pump station through the interface 103, the piston 104 is arranged in the hydraulic cylinder 102, and the piston 104 is slidably connected with the hydraulic cylinder 102, the piston 104 is connected with the locking nut 105 through threads, and the piston 104 is provided with a self-locking bolt 112.

[0033] As shown in Figure 2 and Figure 3 , the hydraulic cylinder 102 is provided with an oil cavity 111 and a linkage cavity 109, the oil cavity 111 and the linkage cavity 109 are communicated, the diameter of the oil cavity 111 is greater than that of the linkage cavity 109, the oil cavity 111 is located above the linkage cavity 109, the hydraulic cylinder 102 is provided with a flow channel 110, the flow channel 110 comprises a horizontal section and a vertical section, the horizontal section of the flow channel 110 is connected with the interface 103, the vertical section of the flow channel 110 is communicated with the oil cavity 111, and the horizontal section of the flow channel 110 and the vertical section of the flow channel 110 are communicated.

[0034] As shown in Figure 2 , the piston 104 comprises an upper part and a lower part, the diameter of the upper part is greater than that of the lower part, the piston 104 is provided with a connecting hole 106 penetrating the upper part and the lower part, an inner thread is arranged on the hole wall of the connecting hole 106, the inner thread is used for connecting with a bolt, the diameter of the connecting hole 106 is equal to that of the bolt, and the outer side of the upper part of the piston 104 is provided with an outer thread, which is used for connecting with the locking nut 105.

[0035] The thread for connecting the lock nut 105 and the piston 104 is a sawtooth thread, the thread of which comprises a first thread surface and a second thread surface, the first thread surface being at an angle of 7° to the rotation axis (the rotation axis being a straight line where the rotation axis of the lock nut is located), and the second thread surface being at an angle of 45° to the rotation axis.

[0036] The lower part of the piston 104 is in sliding connection with the linkage cavity 109.

[0037] As shown in Figure 2 and Figure 4 , the piston 104 is provided with a sliding member 115 on the outside, the sliding member 115 being in sliding connection with the inner wall of the oil cavity 111, the external thread provided on the piston 104 being above the sliding member 115, and a V-shaped spring energy storage ring 121 being provided below the sliding member 115.

[0038] The lower end surface of the upper part of the piston 104 is provided with an annular groove 120, the annular groove 120 being in communication with the flow channel 110.

[0039] As shown in Figure 5 , the lock nut 105 is provided with six connecting holes 117 for connecting a screwing tool.

[0040] In the use of the hydraulic nut mounting bolt,

[0041] a. The hydraulic nut is connected with the bolt through the internal thread on the piston 104, the piston 104 in the hydraulic cylinder 102 is pushed by the ultra-high pressure oil, and the bolt subjected to force is stretched in the elastic deformation zone thereof;

[0042] b. The lock nut 105 is screwed, so that the bolt is locked in the stretched position.

[0043] The above is only the preferred specific implementation manner of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art, according to the technical scheme and the inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, all should be covered in the protection scope of the present application.

Claims

1. A back-off prevention hydraulic nut, comprising a hydraulic cylinder, a piston and a locking nut, an oil cavity of the hydraulic cylinder is connected with an external pump station through a flow channel, the piston is located in the oil cavity of the hydraulic cylinder and is in sliding connection with the hydraulic cylinder, the piston is in ring structure and is provided with an inner thread and an outer thread, the piston is connected with a bolt through the inner thread, and the piston is connected with the locking nut through the outer thread, characterized in that, The thread for connecting the locking nut and the piston is a sawtooth thread.

2. The anti-backup hydraulic nut of claim 1, wherein, The thread of the sawtooth thread comprises a first thread surface and a second thread surface, the first thread surface is at an angle of 7° with the rotation axis, the second thread surface is at an angle of 45° with the rotation axis, and the rotation axis refers to the straight line where the rotation axis of the locking nut is located.

3. The back-off prevention hydraulic nut according to claim 2, wherein The first thread surface provided on the locking nut is opposite to the first thread surface provided on the piston, and abuts when the hydraulic nut is depressurized.

4. The back-off prevention hydraulic nut according to claim 1, wherein The hydraulic cylinder is provided with an oil cavity and a linkage cavity, the oil cavity and the linkage cavity are communicated, the oil cavity is above the linkage cavity, and the diameter of the oil cavity is larger than the diameter of the linkage cavity.

5. The back-off prevention hydraulic nut according to claim 1, wherein The piston comprises an upper part and a lower part, the diameter of the upper part is larger than the diameter of the lower part, the outer side of the upper part is provided with a sliding member, the sliding member is in sliding connection with the inner wall of the oil cavity, the outer thread of the piston is provided on the outer side of the upper part, the outer thread of the piston is above the sliding member, and the lower part of the piston is in sliding connection with the linkage cavity.

6. The back-off prevention hydraulic nut of claim 5, wherein, The middle part of the piston is provided with a connecting hole penetrating upward and downward, the inner thread is provided on the hole wall of the connecting hole, and the diameter of the connecting hole is equal to the diameter of the bolt.

7. The back-off prevention hydraulic nut of claim 1, wherein, The piston is provided with a groove, and the groove is communicated with the flow channel.

8. The backout prevention hydraulic nut of claim 5, wherein, The lower side of the sliding member is provided with a sealing member, and the sealing member is a V-shaped spring energy storage ring.

9. The back-off prevention hydraulic nut of claim 1, wherein, The locking nut is provided with a plurality of connecting holes for connecting the turning tool.

Images