CN104476173B - A kind of method preventing screw thread pair thread gluing during large-diameter thread dismounting - Google Patents

Abstract

The invention discloses a method for preventing the thread pair from sticking when disassembling and assembling large-diameter threads. The excess hydraulic oil in the cylinder overflows through the relief valve, the piston rod retracts slowly, and the support frame descends accordingly. Slowly rotate the male thread workpiece while lowering the male thread workpiece, and the pressure of the hydraulic control system remains unchanged; when disassembling the thread, adjust The pressure of the constant pressure variable pump makes the supply pressure of the hydraulic control system slightly larger than the weight of the male threaded workpiece, the piston rod slowly extends, the constant pressure variable pump synchronously replenishes the hydraulic oil with the extension of the piston rod, and the support frame is lifted accordingly, and at the same time Slowly rotate the male threaded workpiece to go up and disengage from the female threaded workpiece, and the pressure of the hydraulic control system remains unchanged. The method of the invention is simple and easy to implement, and the threads are evenly stressed and not easy to be damaged and bonded.

Description

A method for preventing thread pairs from sticking when large-diameter threads are disassembled

technical field

The invention belongs to the technical field of mechanical manufacturing, and is used for preventing thread pair sticking when disassembling and assembling large-diameter threads, especially large-diameter and heavy-loaded large-scale threads. Methods.

Background technique

Threaded connection is a commonly used connection method between various parts in mechanical equipment. It is widely used because of its many advantages such as convenient disassembly and assembly, large load capacity, and good neutrality between connecting parts. Although the threaded connection has many advantages, in the disassembly process of some large-diameter, heavy-duty threads, due to the influence of the self-weight of the equipment itself, there is a poor alignment when the horizontal butt joint is fastened, and at the same time, due to the influence of the external dimensions of the connecting parts, the equipment cannot be clamped. It is not easy to operate; when the vertical butt joint is fastened, the friction between the thread pairs is large, which often leads to the thread pairs sticking and sintering, and finally the threads cannot be disassembled. For example, the 27"STUB-ACME threaded connection between the underwater horizontal Christmas tree and the lower hydraulic connector must be fastened in place before entering the underwater operation, while the Christmas tree The total weight is 55 tons. Due to the influence of the size of the tree, the horizontal butt joint fastening thread cannot be used, and the vertical butt joint tightening method is adopted. The advantage is that the neutrality is good, and the disadvantage is that the connecting thread is affected by the weight of the underwater tree itself. , resulting in a large friction between the thread pairs, and the thread pairs are stuck and sintered, and finally the threads cannot be disassembled.

Contents of the invention

The purpose of the present invention is to provide a method for preventing thread pairs from sticking when large-diameter threads are disassembled, which solves the influence of the equipment's own weight in the prior art, which causes large friction between thread pairs and prevents thread pairs from sticking. Sintering, which eventually leads to the problem that the thread cannot be disassembled.

The technical solution adopted in the present invention is that a method for preventing the thread pair from sticking when the large-diameter thread is disassembled relies on a disassembly mechanism, the structure of which is that a liquid cylinder base is arranged in the inner hole of the female thread workpiece, A supporting cylinder is installed on the base of the hydraulic cylinder, the piston rod of the supporting cylinder is upwardly connected with the support frame by a spherical hinge, and the upper end surface of the support frame is connected with the lower end surface of the male thread workpiece; The pump and the overflow valve are connected at the same time, and the connecting pipeline between the support cylinder and the hydraulic control system is led out through the base of the hydraulic cylinder. In the hydraulic control system, the constant pressure variable pump is used for pressure supply, and the overflow valve is used for pressure regulation.

Utilize above-mentioned dismounting mechanism, this method is implemented according to the following steps:

Place and align the male thread workpiece and the female thread workpiece to be connected according to the spatial position of the male thread on the top and the female thread on the bottom, set a support cylinder and a support frame in the inner hole of the female thread workpiece, and use a constant pressure variable pump to pump the support liquid. Pour hydraulic oil into the cylinder and push the support frame to move upward until the upper end surface of the support frame closely fits the lower end surface of the male threaded workpiece.

When screwing the thread, adjust the overflow valve so that the supply pressure of the hydraulic control system is slightly smaller than the weight of the male threaded workpiece, the excess hydraulic oil in the support cylinder overflows through the overflow valve, the piston rod retracts slowly, and the support frame follows Descending, slowly turning the male threaded workpiece while lowering the male threaded workpiece, the pressure of the hydraulic control system remains unchanged;

When disassembling the thread, adjust the pressure of the constant pressure variable pump so that the supply pressure of the hydraulic control system is slightly greater than the weight of the male threaded workpiece, the piston rod slowly extends, and the constant pressure variable pump synchronously replenishes hydraulic oil with the extension of the piston rod, and the support frame Thereupon it is lifted, and at the same time, the male threaded workpiece is slowly rotated upward to disengage from the female threaded workpiece, and the pressure of the hydraulic control system remains constant.

The method for preventing the thread pair from sticking when the large-diameter thread is disassembled according to the present invention is also characterized in that:

The structure of the supporting frame is that it includes a lower bracket which is spherically hinged with the end of the piston rod, and the lower bracket is upwardly supported by an upper bracket through a bearing.

The support cylinder and the base of the cylinder are connected by bolts.

The beneficial effect of the invention is that it can effectively avoid the increase of the friction force on the thread pair due to the self-weight of the equipment itself when the thread is disassembled, resulting in sticking and sintering of the connecting thread. The specific features are:

1) It can effectively reduce the positive pressure on the surface of the screw thread during the screwing process, thereby greatly reducing the friction between the threads, and avoiding the phenomenon of sticking and burning when the thread is tightened to the greatest extent.

2) Replacing the support frame and the base of the hydraulic cylinder can meet the disassembly and assembly requirements of threads of different specifications.

Description of drawings

Fig. 1 is the dismounting mechanism that the inventive method adopts in working state schematic diagram;

Fig. 2 is a schematic diagram of the spherical hinge of the support frame and the piston rod in the dismounting mechanism adopted by the method of the present invention.

In the figure, 1. Support frame, 2. Support hydraulic cylinder, 3. Hydraulic control system, 4. Hydraulic cylinder base, 5. Upper bracket, 6. Bearing, 7. Lower bracket, 8. Piston rod, 9. Constant pressure variable Pump, 10. overflow valve, 11. male thread workpiece, 12. female thread workpiece.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

With reference to Fig. 1, the structure of the dismounting mechanism that the inventive method adopts is that the male thread workpiece 11 and the female thread workpiece 12 are vertically aligned, and the male thread workpiece 11 is on the top, and the female thread workpiece 12 is below; A liquid cylinder base 4 is arranged in the hole, and a support liquid cylinder 2 is installed on the liquid cylinder base 4. The piston rod 8 of the support liquid cylinder 2 is upwardly connected with the support frame 1 by a spherical hinge, and the upper end surface of the support frame 1 is connected with the male thread workpiece 11. The lower end surface is connected to the top; the oil inlet of the support cylinder 2 is connected with the constant pressure variable pump 9 and the overflow valve 10 at the same time, and the connecting pipeline between the support cylinder 2 and the hydraulic control system 3 is led out through the base 4 of the hydraulic cylinder, and the hydraulic control system The constant pressure variable pump 9 is used for pressure supply, and the overflow valve 10 is used for pressure regulation.

Referring to Fig. 2, the structure of the support frame 1 is to include a lower bracket 7 that is spherically hinged with the ends of the piston rod 8, and the lower bracket 7 supports the upper bracket 5 upwardly through the bearing 6, and the bearing 6 can minimize the load while satisfying the load. The friction between the male threaded workpiece 11 and the female threaded workpiece 12 during the threading process.

The support frame 1 is replaced according to the external dimensions and weight of the male threaded workpiece 11, so as to meet the requirements for disassembly and assembly of workpieces with different specifications. The support frame 1 and the support cylinder piston rod 8 are spherically hinged, which can compensate for the misalignment between the thread pair and the support cylinder 2 .

The support cylinder 2 and the cylinder base 4 are connected by bolts, which can be replaced according to the shape and height of the female screw workpiece 12 to meet the requirements of products with different specifications.

During the twisting process, no matter fastening or dismounting, the supply pressure of the hydraulic control system 3 remains stable.

The course of work of the inventive method is, utilizes above-mentioned dismounting mechanism, implements according to the following steps:

Align the male threaded workpiece 11 and the female threaded workpiece 12 to be connected according to the spatial position of the male thread on the top and the female thread on the bottom, set the support cylinder 2 and the support frame 1 in the inner hole of the female thread workpiece 12, and use constant pressure The variable pump 9 injects hydraulic oil into the support cylinder 2, and pushes the support frame 1 to move upward until the upper end surface of the support frame 1 is closely attached to the lower end surface of the male threaded workpiece 11.

When screwing the thread, adjust the overflow valve 10 so that the supply pressure of the hydraulic control system 3 is slightly smaller than the weight of the male threaded workpiece 11, and the excess hydraulic oil in the support cylinder 2 overflows through the overflow valve 10, and the piston rod 8 slowly returns to it. shrink, the support frame 1 descends accordingly, slowly rotate the male thread workpiece 11 while lowering the male thread workpiece 11, and the pressure of the hydraulic control system 3 remains unchanged;

When disassembling the thread, adjust the pressure of the constant pressure variable pump 9 so that the supply pressure of the hydraulic control system 3 is slightly greater than the weight of the male threaded workpiece 11, the piston rod 8 is slowly extended, and the constant pressure variable pump 9 is synchronized with the extension of the piston rod 8 The hydraulic oil is replenished, and the support frame 1 is lifted accordingly, and at the same time, the male threaded workpiece 11 is slowly rotated upward to disengage from the female threaded workpiece 12, and the pressure of the hydraulic control system 3 remains unchanged.

Claims (3)

1. A method for preventing the thread pair from sticking when a large-diameter thread is disassembled is characterized in that it relies on a dismounting mechanism, and its structure is that a liquid cylinder base ( 4), the support liquid cylinder (2) is installed on the liquid cylinder base (4), and the piston rod (8) of the support liquid cylinder (2) adopts ball type hinge upwards to the support frame (1), and the upper part of the support frame (1) The end surface is connected to the lower end surface of the male thread workpiece (11); the oil inlet of the support cylinder (2) is connected with the constant pressure variable pump (9) and the overflow valve (10) at the same time, and the support cylinder (2) is connected to the hydraulic control The connecting pipelines between the systems (3) are led out through the base of the hydraulic cylinder (4). In the hydraulic control system, the constant pressure variable pump (9) is used for pressure supply, and the overflow valve (10) is used for pressure regulation. Utilize above-mentioned dismounting mechanism, this method is implemented according to the following steps: Align the male thread workpiece (11) and the female thread workpiece (12) to be connected according to the spatial position of the male thread on the top and the female thread on the bottom, and set a support cylinder (2) in the inner hole of the female thread workpiece (12) and the support frame (1), inject hydraulic oil into the support liquid cylinder (2) with a constant pressure variable pump (9), and push the support frame (1) to move upward until the upper end surface of the support frame (1) is in contact with the male threaded workpiece ( 11) The lower end surface is tightly fitted, When the screw thread is turned, adjust the overflow valve (10) so that the supply pressure of the hydraulic control system (3) is slightly smaller than the weight of the male threaded workpiece (11), and the excess hydraulic oil in the support cylinder (2) passes through the overflow valve (10 ) overflows, the piston rod (8) slowly retracts accordingly, the support frame (1) descends accordingly, and the male threaded workpiece (11) is slowly rotated while lowering the male threaded workpiece (11), the pressure of the hydraulic control system (3) is always constant Change; When disassembling the thread, adjust the pressure of the constant pressure variable pump (9), so that the supply pressure of the hydraulic control system (3) is slightly greater than the weight of the male threaded workpiece (11), the piston rod (8) is slowly stretched out, and the constant pressure variable pump ( 9) With the extension of the piston rod (8), the hydraulic oil is replenished synchronously, the support frame (1) is lifted accordingly, and at the same time, the male threaded workpiece (11) is slowly rotated upward to disengage from the female threaded workpiece (12), and the hydraulic control system (3 ) pressure remains constant. 2. The method according to claim 1 for preventing the thread pair from sticking when the large-diameter thread is disassembled, characterized in that: the structure of the support frame (1) includes a ball-type joint with the piston rod (8) end. The hinged lower bracket (7), the lower bracket (7) upwardly supports the upper bracket (5) through the bearing (6). 3. The method for preventing thread pair sticking when disassembling and assembling large-diameter threads according to claim 1, characterized in that: the supporting liquid cylinder (2) and the liquid cylinder base (4) are connected by bolts.