A piston structure for a hydraulic pile hammer

Abstract

The present invention introduces a piston structure for a hydraulic pile hammer, comprising a cylinder body and a piston assembly. The piston assembly is arranged in the cylinder body, and the piston assembly divides the cylinder body into two upper and lower cavities. The piston assembly comprises a hammer core, a limit ring, a front sleeve, a rear sleeve, a screw plug, a slider, a pressure ring, a piston ring, a speed reduction ring and a sealing assembly. The entire piston assembly of the present invention has a compact structure and does not have any fasteners, thereby avoiding the problem of fastener threads loosening and falling off under severe vibration conditions; a reasonable sealing system divides the cylinder body into an upper air cavity and a lower liquid cavity to prevent gas and liquid from leaking into each other, and a cavity c and an oil hole leading to cavity c are provided. The internal pressure of cavity c can be released by removing the screw plug, thereby ensuring the convenience and safety of removing the piston assembly; the piston ring has a two-half structure, and the joint surface is in linear contact with the inner wall of the cylinder body, thereby avoiding linear friction between the piston ring and the inner wall of the cylinder body, thereby reducing wear on the inner wall of the cylinder body.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic pile hammers, and in particular to a piston structure for a hydraulic pile hammer. Background Art

[0002] If the hydraulic system of a hydraulic pile hammer controls only one oil chamber, the hammer core rises when oil is introduced and falls when oil is drained. The upper chamber is filled with compressed air at a certain pressure, which increases the hammer core's striking energy as it falls. This type of hydraulic pile hammer is also called a "gas-liquid hammer." The piston diameter of a "gas-liquid hammer" is generally large, and the hammer core and piston are integrated. The vibration generated by the hammer core's impact is directly transmitted to the piston, which impairs the piston's sealing environment. One end of the piston is oil, and the other end is air. To prevent oil and air from mixing, a suitable sealing structure is required. In addition, the vibration generated by the hammer core's impact is so great that the threads of typical fasteners are easily loosened. If the fastener falls off, it will scratch the oil cylinder, resulting in a poor seal. In more serious cases, it will interfere with the raising and lowering of the hammer core and damage the equipment. Therefore, designing a reasonable piston structure is crucial. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a piston structure for a hydraulic pile hammer, which has a compact structure, a reasonable sealing structure, and does not use fasteners, thereby avoiding the problem of fastener threads loosening and falling off under severe vibration environments.

[0004] The technical solution adopted in the present invention is:

[0005] A piston structure for a hydraulic pile hammer, comprising a cylinder body and a piston assembly, wherein the piston assembly is disposed in the cylinder body and separates the cylinder body into two upper and lower cavities, and the piston assembly comprises a hammer core, a limit ring, a front sleeve, a rear sleeve, a screw plug, a slider, a pressure ring, a piston ring, a speed reducer ring, and a sealing assembly;

[0006] The outer edge of the hammer core is provided with a limit ring mounting groove and a piston ring mounting groove; the limit ring, front sleeve, rear sleeve, pressure ring, piston ring and speed reducer ring are arranged on the outer edge of the hammer core in sequence; the upper end of the front sleeve is provided with a step groove matching the limit ring, and a sealing ring is provided on the inner wall of the lower end of the front sleeve and between the outer edge of the hammer core; the limit ring is a two-semicircular structure, and the limit ring is arranged between the upper limit ring mounting groove of the hammer core and the step groove on the upper end of the front sleeve;

[0007] Two circles of sealing ring grooves are provided on the inner wall of the rear sleeve, and the sealing rings are respectively arranged in the sealing ring grooves. A circle of convex ring is provided between the two circles of sealing ring grooves, and an annular closed cavity c is formed between the two circles of sealing rings and the convex ring and the outer edge of the hammer core. The inner wall of the lower end of the rear sleeve is provided with a step structure matching the pressure ring, and the upper end face and outer edge of the rear sleeve are provided with oil holes that are perpendicular to each other, and the ends of the oil holes are connected to the cavity c; the screw plugs are respectively provided on the two outer ends of the oil holes; the slider is provided between the screw plug on the outer edge of the rear sleeve and the inner wall of the cylinder body; the outer wall of the pressure ring is a step structure, and the pressure ring is provided between the step structure at the lower end of the rear sleeve and the hammer core; the piston ring is provided in the piston ring mounting ring groove on the lower side of the rear sleeve; the piston ring is a two-half structure, and the joint surface of the two-half piston rings is inclined at an angle of 10° to 20° to the axial section; the speed reduction ring is provided on the outer edge of the hammer core on the lower side of the piston ring; the sealing components are respectively provided between the outer edges of the lower ends of the front sleeve and the rear sleeve and the inner wall of the cylinder body.

[0008] Specifically, the piston assembly divides the cylinder into two areas, the upper part of the piston assembly is the air chamber a, which is filled with compressed air with a pressure value P1; the lower part of the piston assembly is the liquid chamber b, which is filled with pressure oil with a pressure value P2.

[0009] Specifically, the screw plug at the end of the oil hole on the upper end surface of the rear sleeve is welded.

[0010] Specifically, the slider is made of nylon or soft copper.

[0011] Specifically, the outer edge of the lower end of the deceleration device is a conical structure.

[0012] Specifically, a plurality of annular oil grooves are evenly arranged on the outer edge of the piston ring, and a plurality of groups of oil outlet holes are correspondingly arranged on each annular oil groove. A plurality of oil inlet holes perpendicular to each group of oil outlet holes are evenly arranged on the upper end surface of the piston ring.

[0013] When installing the piston assembly of the present invention, first install the reduction ring, the pressure ring and the two sealing rings on the inner wall of the rear sleeve into the hammer core, then install the sealing assembly onto the outer edge of the rear sleeve and then install the rear sleeve into the hammer core, then install the sealing ring on the inner wall of the front sleeve and the sealing assembly on the outer edge into the front sleeve and then install them together into the hammer core, then move the above installed parts toward the lower part of the hammer core to expose the installation position of the two halves of the limit ring, clamp the two halves of the limit ring on the limit ring installation groove, then move the above components to their original positions to expose the piston ring installation position, and then install the piston ring into the piston ring installation groove.

[0014] After the piston assembly is assembled, it is installed in the cylinder body. The piston assembly can move up and down in the cylinder body. The piston assembly divides the cylinder body into two upper and lower areas: the upper part of the piston assembly is the air chamber a, which is filled with compressed air with a pressure value of P1; the lower part of the piston assembly is the liquid chamber b, which is filled with pressure oil with a pressure value of P2; the sealing ring and sealing assembly on the front sleeve play a role in isolating the compressed air in the upper air chamber a from entering the lower liquid chamber b, and the sealing ring and sealing assembly on the rear sleeve play a role in isolating the pressure oil in the lower liquid chamber b from entering the upper air chamber a; in addition, two seals on the inner wall of the rear sleeve A closed cavity c is formed between the convex ring between the road sealing rings and the outer edge of the hammer core, with a pressure value of P3. When the pressure in the liquid cavity b is higher than that in the cavity c, the pressure oil in the liquid cavity b can enter the cavity c until the pressure in the cavity c is higher than that in the liquid cavity b. The cavity c contains a gas-liquid mixture, and the gas is compressible, so the final pressure in the cavity c is slightly higher than the maximum pressure in the liquid cavity b; there is always a higher pressure in the cavity c. The screw plug on the outer edge of the rear sleeve is removed before removing the piston assembly, which can relieve the pressure in the cavity c and ensure the convenience and safety of subsequent removal of the piston assembly.

[0015] The piston ring is processed as a whole ring. After the processing is completed, it is divided into two halves and cannot be fastened in the piston ring mounting groove. The pressure ring can press the piston ring to prevent it from loosening. When the pressure value P2 in the liquid chamber b is greater than the pressure value P1 in the air chamber a, the piston assembly moves upward and the pressure ring is subjected to a downward force. Subject to an upward force Because the pressure value P3 in cavity c is slightly higher than P1, the pressure ring is pressed down by the piston ring; when the pressure value P2 in liquid cavity b is lower than the pressure value P1 in air cavity a, the piston assembly moves downward and the pressure ring is pressed down by the pressure ring. Subject to an upward force At this time, the pressure value P3 in cavity c is much higher than the pressure value P2 in liquid cavity b, so the pressure ring is still pressed down by the piston ring, and the above friction and gravity are negligible; in the above formula, d1 is the inner diameter of the pressure ring, and d2 is the outer diameter of the small diameter section of the pressure ring step structure.

[0016] The lower part of the deceleration ring is conical. When the hammer core is in free fall, the gap S between the lower conical section of the deceleration ring and the upper part of the oil distribution ring becomes smaller, and the pressure in the liquid chamber b increases sharply, which produces a huge upward force on the hammer core, slowing down the falling speed of the hammer core and protecting the hammer core from overshoot.

[0017] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0018] The entire piston assembly of the present invention has a compact structure and does not have any fasteners, which avoids the problem of fastener threads loosening and falling off under severe vibration environments; a reasonable sealing system divides the cylinder body into an upper air chamber and a lower liquid chamber to prevent gas and liquid from leaking into each other, and a cavity C and an oil hole leading to the cavity C are provided. When the piston assembly is inspected and disassembled, the internal pressure of the cavity C can be released by removing the screw plug on the outer edge of the rear sleeve, and the piston ring can be removed, ensuring convenience and safety when removing the piston assembly; the piston ring has a two-half structure, and the mating surface is in linear contact with the inner wall of the cylinder body, which avoids linear friction between the piston ring and the inner wall of the cylinder body at right angles, and reduces wear on the inner wall of the cylinder body; the setting of the slider prevents the piston assembly from moving up and down in the cylinder body and scratching the inner wall of the cylinder body when the screw plug here is loose. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic cross-sectional view of the overall installation of the present invention.

[0020] Figure 2 yes Figure 1 Schematic diagram of the middle piston assembly after it moves downward within the cylinder body.

[0021] Figure 3 It is a schematic cross-sectional view of the piston assembly of the present invention.

[0022] Figure 4 yes Figure 3 A partial enlarged view of P in the middle.

[0023] Figure 5 Schematic diagram of the piston ring of the present invention.

[0024] In the figure: 1-cylinder body, 2-piston assembly, 3-hammer core, 4-limiting ring, 5-front sleeve, 6-rear sleeve, 7-screw plug, 71-oil hole, 8-slider, 9-pressure ring, 10-piston ring, 101-oil inlet hole, 102-oil outlet hole, 11-reduction ring, 12-sealing ring, 13-sealing assembly, 14-oil distribution ring. DETAILED DESCRIPTION

[0025] The present invention will be further explained below with reference to the accompanying drawings and embodiments, which should not be used to limit the scope of protection of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0026] Combined with attachment Figure 1-5 The piston structure shown is for a hydraulic pile hammer, comprising a cylinder body 1 and a piston assembly 2. The piston assembly 2 is disposed within the cylinder body 1 and divides the cylinder body 1 into two upper and lower cavities. The piston assembly 2 comprises a hammer core 3, a limiting ring 4, a front sleeve 5, a rear sleeve 6, a screw plug 7, a slider 8, a pressure ring 9, a piston ring 10, a reduction ring 11, and a sealing assembly 13.

[0027] A limit ring mounting groove and a piston ring mounting groove are provided on the outer edge of the hammer core 3; the limit ring 4, the front sleeve 5, the rear sleeve 6, the pressure ring 9, the piston ring 10 and the speed reduction ring 11 are sequentially provided on the outer edge of the hammer core 3; the upper end of the front sleeve 5 is provided with a step groove matching the limit ring 4, and a sealing ring 12 is provided on the inner wall of the lower end of the front sleeve 5 and between the outer edge of the hammer core 3; the limit ring 4 is two semicircular structures, and the limit ring 4 is provided between the limit ring mounting groove on the hammer core 3 and the step groove on the upper end of the front sleeve 5.

[0028] Two circles of sealing ring grooves are provided on the inner wall of the rear sleeve 6, and the sealing rings 12 are respectively arranged in the sealing ring grooves. A circle of convex ring is provided between the two circles of sealing ring grooves. An annular closed cavity c is formed between the two circles of sealing rings 12, the convex ring and the outer edge of the hammer core 3. The inner wall of the lower end of the rear sleeve 6 is provided with a step structure matching the pressure ring 9. The upper end face and outer edge of the rear sleeve 6 are provided with a vertical through oil hole 71, and the end of the oil hole 71 passes into the cavity c; the screw plug 7 is respectively provided on the two outer ends of the oil hole 71, and the end of the screw plug 7 at the end of the oil hole 71 on the upper end face of the rear sleeve 6 is welded; the slider 8 is provided between the screw plug 7 on the outer edge of the rear sleeve 6 and the inner wall of the cylinder body 1, and the slider 8 is made of nylon or soft copper; the outer wall of the pressure ring 9 is a step structure, and the pressure ring 9 is provided between the step structure at the lower end of the rear sleeve 6 and the hammer core 3.

[0029] The piston ring 10 is arranged in the piston ring mounting groove on the lower side of the rear sleeve 6. The piston ring 10 is a two-half structure. The joint surface of the two-half piston ring 10 is inclined at an angle of 10° to 20° to the axial section. A number of annular oil grooves are evenly arranged on the outer edge of the piston ring 10, and a number of groups of oil outlet holes 102 are correspondingly arranged on each annular oil groove. A number of oil inlet holes 101 that are perpendicular to each group of oil outlet holes 102 are evenly arranged on the upper end surface of the piston ring; the outer edge of the lower end of the reduction ring 11 is a conical structure, and the reduction ring 11 is arranged on the outer edge of the hammer core 3 on the lower side of the piston ring 10; the sealing assembly 13 is respectively arranged between the outer edges of the lower ends of the front sleeve 5 and the rear sleeve 6 and the inner wall of the cylinder body 1.

[0030] When installing the piston assembly 2 of the present invention, first install the reduction ring 11, the pressure ring 9 and the two sealing rings 12 on the inner wall of the rear sleeve 6 into the hammer core 3, then install the sealing assembly 13 into the outer edge of the rear sleeve 6, and then install the rear sleeve 6 into the hammer core 3, and then install the sealing ring 12 on the inner wall of the front sleeve 5 and the sealing assembly 13 on the outer edge into the front sleeve 5, and then install them together into the hammer core 3, then move the above assembled parts to the lower part of the hammer core 3 to expose the installation position of the two halves of the limit ring 4, and then clamp the two halves of the limit ring 4 on the limit ring installation groove on the outer edge of the hammer core 3, and then move the above components to their original positions to expose the installation position of the piston ring 10, and then install the piston ring 10 into the piston ring installation groove on the outer edge of the hammer core 3.

[0031] After the piston assembly 2 is assembled, it is installed in the cylinder body 1. The piston assembly 2 can move up and down in the cylinder body 1. The piston assembly 2 divides the cylinder body 1 into two upper and lower areas: the upper part of the piston assembly 2 is the air chamber a, which is filled with compressed air with a pressure value P1; the lower part of the piston assembly 2 is the liquid chamber b, which is filled with pressure oil with a pressure value P2; the sealing ring 12 and the sealing assembly 13 on the front sleeve 5 play a role in isolating the compressed air in the upper air chamber a from entering the lower liquid chamber b, and the sealing ring 12 and the sealing assembly 13 on the rear sleeve 6 play a role in isolating the pressure oil in the lower liquid chamber b from entering the upper air chamber a; in addition, A closed cavity c is formed between the two sealing rings and the convex ring on the inner wall of the rear sleeve 6 and the outer edge of the hammer core 3, with a pressure value of P3. When the pressure in the liquid cavity b is higher than that in the cavity c, the pressure oil in the liquid cavity b can enter the cavity c until the pressure in the cavity c is higher than that in the liquid cavity b. The cavity c contains a gas-liquid mixture, and the gas is compressible, so the final pressure in the cavity c is slightly higher than the maximum pressure in the liquid cavity b; there is always a higher pressure in the cavity c. The screw plug 7 on the outer edge of the rear sleeve 6 is removed before the piston assembly 2 is removed, so that the pressure in the cavity c can be relieved, ensuring the convenience and safety of subsequent removal of the piston assembly 2.

[0032] The piston ring 10 is processed as a whole ring and is divided into two halves after processing. It cannot be fastened in the mounting ring groove of the piston ring 10. The pressure ring 9 can press the piston ring 10 to prevent it from loosening. When the pressure value P2 in the liquid chamber b is greater than the pressure value P1 in the air chamber a, the piston assembly 2 moves upward and the pressure ring 9 is subjected to a downward force. Subject to upward force Because the pressure value P3 in cavity c is slightly higher than P1, the pressure ring 9 is pressed downward against the piston ring 10; when the pressure value P2 in liquid cavity b is lower than the pressure value P1 in air cavity a, the piston assembly 2 moves downward, and the pressure ring 9 is pressed downward. Subject to an upward force At this time, the pressure value P3 in cavity c is much higher than the pressure value P2 in liquid cavity b, so the pressure ring 9 is still pressed downward by the piston ring 10, and the above friction and gravity are negligible; in the above formula, d1 is the inner diameter of the pressure ring 9, and d2 is the outer diameter of the small diameter section of the step structure of the pressure ring 9.

[0033] The lower part of the deceleration ring 11 is conical. When the hammer core 3 is in free fall, the gap S between the lower conical section of the deceleration ring 11 and the upper part of the oil distribution ring 14 becomes smaller, and the pressure in the liquid chamber b increases sharply, which generates a huge upward force on the hammer core 3, slowing down the falling speed of the hammer core 3 and protecting the hammer core 3 from overshoot.

[0034] The parts not described in detail in this invention are prior art.

[0035] The embodiments selected herein for the purpose of disclosing the invention are presently considered suitable, but it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of the concept and invention.

Claims

1. A piston structure for a hydraulic pile hammer, characterized in that: It includes a cylinder body and a piston assembly. The piston assembly is arranged in the cylinder body and the piston assembly divides the cylinder body into two upper and lower cavities. The piston assembly includes a hammer core, a limit ring, a front sleeve, a rear sleeve, a screw plug, a slider, a pressure ring, a piston ring, a speed reducer ring and a sealing assembly. The outer edge of the hammer core is provided with a limit ring mounting groove and a piston ring mounting groove; the limit ring, front sleeve, rear sleeve, pressure ring, piston ring and speed reducer ring are arranged on the outer edge of the hammer core in sequence; the upper end of the front sleeve is provided with a step groove matching the limit ring, and a sealing ring is provided on the inner wall of the lower end of the front sleeve and between the outer edge of the hammer core; the limit ring is a two-semicircular structure, and the limit ring is arranged between the upper limit ring mounting groove of the hammer core and the step groove on the upper end of the front sleeve; Two circles of sealing ring grooves are provided on the inner wall of the rear sleeve, and the sealing rings are respectively arranged in the sealing ring grooves. A circle of convex ring is provided between the two circles of sealing ring grooves, and an annular closed cavity c is formed between the two circles of sealing rings and the convex ring and the outer edge of the hammer core. The inner wall of the lower end of the rear sleeve is provided with a step structure matching the pressure ring, and the upper end face and outer edge of the rear sleeve are provided with oil holes that are perpendicular to each other, and the ends of the oil holes pass into the cavity c; the screw plugs are respectively provided on the two outer ends of the oil holes; the slider is provided between the screw plug on the outer edge of the rear sleeve and the inner wall of the cylinder body; the outer wall of the pressure ring is a step structure, and the pressure ring is provided between the step structure at the lower end of the rear sleeve and the hammer core; the piston ring is provided in the piston ring mounting ring groove on the lower side of the rear sleeve; the piston ring is a two-half structure, and the joint surface of the two-half piston rings is inclined at an angle of 10°~20° to the axial section; the speed reduction ring is provided on the outer edge of the hammer core on the lower side of the piston ring; the sealing components are respectively provided between the outer edges of the lower ends of the front sleeve and the rear sleeve and the inner wall of the cylinder body.

2. The piston structure for a hydraulic pile hammer according to claim 1, characterized in that: The piston assembly divides the cylinder into two areas, the upper part of the piston assembly is the air chamber a, which is filled with compressed air with a pressure value P1; the lower part of the piston assembly is the liquid chamber b, which is filled with pressure oil with a pressure value P2.

3. The piston structure for a hydraulic pile hammer according to claim 1, characterized in that: The screw plug at the end of the oil hole on the upper end surface of the rear sleeve is welded.

4. The piston structure for a hydraulic pile hammer according to claim 1, characterized in that: The sliding block is made of nylon or soft copper.

5. The piston structure for a hydraulic pile hammer according to claim 1, characterized in that: The outer edge of the lower end of the deceleration ring is a conical structure.

6. The piston structure for a hydraulic pile hammer according to claim 1, characterized in that: The outer edge of the piston ring is evenly provided with a plurality of annular oil grooves, each annular oil groove is correspondingly provided with a plurality of groups of oil outlet holes, and the upper end surface of the piston ring is evenly provided with a plurality of oil inlet holes perpendicular to each group of oil outlet holes.

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