A combined piston structure of a cylinder

Abstract

This invention discloses a cylindrical hydraulic cylinder with a combined piston structure, including a hydraulic piston inside a hydraulic cylinder tube. The hydraulic piston is composed of a first piston ring and a second piston ring coaxially combined. A magnetic ring is coaxially clamped between the first piston ring and the second piston ring, and there is a gap between the magnetic ring and the hydraulic cylinder tube. This improves the stability of piston operation and enhances its anti-fouling performance.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic cylinders. Background Technology

[0002] The magnetic ring on the piston of the hydraulic cylinder can attract and capture iron-containing impurities generated during the operation of the hydraulic cylinder, thereby protecting the sliding surfaces and seals inside the hydraulic cylinder. Since the magnetic ring needs to be fitted on the outside of the piston, it is necessary to expand the diameter during the assembly process. Therefore, the magnetic ring generally needs to be made into an open-ring structure. At the same time, in order to facilitate the expansion, the width and thickness of the magnetic ring cannot be too large. Otherwise, the expansion process will be difficult and irreversible deformation may easily occur.

[0003] Meanwhile, existing piston structures are generally single-piston structures. The stability of this single-piston structure is poor, and wear will increase when the piston rod is subjected to bending moment. At the same time, this single-piston structure does not have enough space to simultaneously assemble wear-resistant sealing rings and magnetic rings. In addition, existing hydraulic cylinders do not have the ability to automatically identify local damage to the inner wall of the steel pipe. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a cylindrical oil cylinder with a combined piston structure, which can improve the efficiency of adsorbing iron powder impurities.

[0005] Technical solution: To achieve the above objectives, the present invention provides a cylindrical hydraulic cylinder with a combined piston structure, comprising a hydraulic piston inside a hydraulic cylinder tube, wherein the hydraulic piston is composed of a first piston ring and a second piston ring coaxially combined; a magnetic ring is coaxially clamped between the first piston ring and the second piston ring, and there is a gap between the magnetic ring and the hydraulic cylinder tube.

[0006] Furthermore, the magnetic ring is a plastic magnetic ring.

[0007] Furthermore, the piston rod includes a first stepped shaft, a second stepped shaft, and a third stepped shaft along its length; both the first piston ring and the second piston ring are sleeved on the second stepped shaft; a first buffer ring is sleeved on a section of the second stepped shaft near the first stepped shaft; the third stepped shaft is provided with external threads, and a second buffer ring is coaxially threaded on the outside of the third stepped shaft.

[0008] With the external threads of the second buffer ring and the third stepped shaft tightened, the hydraulic piston is coaxially clamped between the first buffer ring and the second buffer ring, and the first buffer ring is clamped between the first stepped shaft and the first piston ring.

[0009] Furthermore, the wall of the second buffer ring has a radially penetrating internal thread hole, in which a locking screw is threaded and fitted. A copper washer is placed at the bottom of the internal thread hole. When the locking screw is tightened, the copper washer tightly presses against the external thread of the third stepped shaft, thereby locking the second buffer ring.

[0010] Furthermore, the second stepped shaft is provided with a first annular groove and a second annular groove, and the sealing rings in the first annular groove and the second annular groove respectively seal with the inner rings of the first piston ring and the second piston ring.

[0011] Furthermore, the outer rings of the first piston ring and the second piston ring are respectively provided with a first wear-resistant ring groove and a second wear-resistant ring groove, and a first wear-resistant sealing ring and a second wear-resistant sealing ring are respectively provided in the first wear-resistant ring groove and the second wear-resistant ring groove.

[0012] Furthermore, a strain gauge mounting groove is provided on the side of the first piston ring near the second piston ring, and an annular pressure strain gauge is provided in the strain gauge mounting groove. The end of the second piston ring near the first piston ring presses against the annular pressure strain gauge.

[0013] Furthermore, it also includes a stroke positioning pin that is coaxially threaded onto a fixed end cap at one end of the hydraulic cylinder tube.

[0014] Beneficial effects: The dual-piston structure of this invention has higher stability and stronger resistance to bending moment than the traditional single-piston structure. Since the hydraulic piston of this invention is assembled by coaxially combining the first piston ring and the second piston ring, there is no need to expand the diameter of the magnetic ring during the installation process. Therefore, there is no need to consider the irreversible deformation of the magnetic ring during the expansion process. Thus, the axial and radial dimensions of the magnetic ring are not limited by the assembly process. As a result, a magnetic ring structure with a larger width and thicker thickness and stronger magnetism can be used, thereby improving the efficiency of adsorbing iron powder impurities. At the same time, it can also achieve the purpose of identifying local damage and determining the location of damage. Attached Figure Description

[0015] Appendix Figure 1 This is an explosion diagram of the proposed scheme;

[0016] Appendix Figure 2 This is an assembly diagram;

[0017] Appendix Figure 3 For the appendix Figure 1 The diagram shows the addition of a stroke positioning column to the existing structure. Detailed Implementation

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] As attached Figure 1 and 2The cylindrical hydraulic cylinder shown is a combined piston structure, including a hydraulic piston 43 inside a hydraulic cylinder tube 18. The upper and lower sides of the hydraulic piston 43 are respectively a first hydraulic chamber 14 and a second hydraulic chamber 15. The hydraulic piston 43 is coaxially assembled from a first piston ring 6 and a second piston ring 8. This dual-piston structure has higher stability and stronger resistance to bending moments than a single piston. An elastic magnetic ring 23 is coaxially clamped between the first piston ring 6 and the second piston ring 8. The magnetic ring 23 can adsorb iron powder formed due to wear inside the hydraulic cylinder tube 18. The magnetic ring 23 is a plastic magnetic ring. There is a gap 22 between the cylinder tubes 18. This gap is used to accumulate iron powder impurities generated by wear in the hydraulic oil and adsorbed by the magnetic ring 23. Since the hydraulic piston 43 is assembled by the first piston ring 6 and the second piston ring 8 coaxially, there is no need to expand the diameter of the magnetic ring 23 during the installation process. Therefore, there is no need to consider the irreversible deformation of the magnetic ring 23 during the expansion process. Thus, the axial and radial dimensions of the magnetic ring 23 are not limited by the assembly process. As a result, a magnetic ring 23 structure with a larger width and thicker thickness and stronger magnetism can be adopted, thereby improving the efficiency of adsorbing iron powder impurities.

[0020] The piston rod 44 includes a first stepped shaft 1, a second stepped shaft 13, and a third stepped shaft 4 along its length. The first piston ring 6 and the second piston ring 8 are both sleeved on the second stepped shaft 13. A first buffer ring 5 is sleeved on a section of the second stepped shaft 13 near the first stepped shaft 1. The third stepped shaft 4 has an external thread, and a second buffer ring 12 is coaxially threaded onto its outer side. When the second buffer ring 12 and the external thread of the third stepped shaft 4 are tightened, the hydraulic piston 43 is coaxially clamped between the first buffer ring 5 and the second buffer ring 12, and the first buffer ring 5 is clamped between the first stepped shaft 1 and the first piston ring 6. An internally threaded hole 11 is radially penetrating the wall of the second buffer ring 12. A locking screw 17 is threaded into the internally threaded hole 11, and a copper washer 16 is provided at the bottom of the hole. When the locking screw 17 is tightened, the copper washer 16 tightly presses against the external thread of the third stepped shaft 4, thereby locking the second buffer ring 12.

[0021] like Figure 3 As shown, it also includes a stroke positioning pin 13 that is coaxially threaded onto a fixed end cap at one end of the hydraulic cylinder tube 18 via a threaded section 14. Under the action of the threaded engagement, the stroke positioning pin 13 makes the retraction distance and stroke of the piston rod 44 adjustable.

[0022] The second stepped shaft 13 has a first annular groove 2 and a second annular groove 3 respectively. The sealing rings in the first annular groove 2 and the second annular groove 3 respectively seal with the inner rings of the first piston ring 6 and the second piston ring 8. The outer rings of the first piston ring 6 and the second piston ring 8 are respectively provided with a first wear-resistant ring groove 7 and a second wear-resistant ring groove 9. A first wear-resistant sealing ring 19 and a second wear-resistant sealing ring 20 are respectively provided in the first wear-resistant ring groove 7 and the second wear-resistant ring groove 9.

[0023] A strain gauge mounting groove 45 is provided on the side of the first piston ring 6 near the second piston ring 8. An annular pressure strain gauge 45 is provided in the strain gauge mounting groove 45. Since the magnetic ring 23 is made of flexible material, when the first piston ring 6 and the second piston ring 8 are squeezed, the magnetic ring 23 will automatically deform. Therefore, the annular pressure strain gauge 45 bears most of the squeezing force between the first piston ring 6 and the second piston ring 8. The larger the pressure value detected by the annular pressure strain gauge 45, the greater the squeezing force between the first piston ring 6 and the second piston ring 8. The end of the second piston ring 8 near the first piston ring 6 presses against the annular pressure strain gauge 45. A lead wire channel 50 is provided in the piston rod 44 for the lead wire to pass through the annular pressure strain gauge 45.

[0024] Inspection process for hydraulic cylinder tube 18 without disassembly:

[0025] After entering the self-test mode, the first hydraulic chamber 14 is brought to a normal pressure state. At the same time, by controlling the corresponding hydraulic pump, the hydraulic piston 43 and piston rod 44 are moved slowly upward from the lower part of the hydraulic cylinder tube 18 to the upper part of the hydraulic cylinder tube 18 at a constant speed under the hydraulic pressure of the second hydraulic chamber 15.

[0026] If the inner wall of the hydraulic cylinder tube 18 does not undergo local deformation or wear, the value detected by the annular pressure strain gauge 45 will be relatively stable during the smooth upward displacement of the hydraulic piston 43, and there will be no sudden jump in value.

[0027] If there is a local deformation or wear on the inner wall of the hydraulic cylinder tube 18, during the smooth upward displacement of the hydraulic piston 43, the first piston ring 6 will touch the locally deformed or damaged inner wall of the hydraulic cylinder tube 18 before the second piston ring 8. When the first piston ring 6 first touches the locally deformed or damaged inner wall of the hydraulic cylinder tube 18, the first piston ring 6 will experience a sudden downward resistance before the second piston ring 8. This sudden resistance is converted into a sudden compressive force between the first piston ring 6 and the second piston ring 8, thereby transmitting the sudden resistance to the annular pressure strain gauge 45, allowing the annular pressure strain gauge 45 to detect the sudden stress. The moment the annular pressure strain gauge 45 detects the sudden stress, it immediately stops the displacement of the hydraulic piston 43. At this moment, the position of the first piston ring 6 is the location of the local deformation or damage on the inner wall of the hydraulic cylinder tube 18, thus achieving the purpose of identifying local damage and determining the location of the damage.

[0028] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cylindrical hydraulic cylinder with a combined piston structure, characterized in that: The hydraulic piston (43) is included in the hydraulic cylinder tube (18). The hydraulic piston (43) is composed of a first piston ring (6) and a second piston ring (8) coaxially combined. A magnetic ring (23) is coaxially clamped between the first piston ring (6) and the second piston ring (8), and there is a gap (22) between the magnetic ring (23) and the hydraulic cylinder tube (18). The magnetic ring (23) is a plastic magnetic ring; The piston rod (44) includes a first stepped shaft (1), a second stepped shaft (13), and a third stepped shaft (4) along its length; the first piston ring (6) and the second piston ring (8) are both sleeved on the second stepped shaft (13); a first buffer ring (5) is sleeved on a section of the second stepped shaft (13) near the first stepped shaft (1); the third stepped shaft (4) is provided with an external thread, and a second buffer ring (12) is fitted on the coaxial thread of the third stepped shaft (4); When the external threads of the second buffer ring (12) and the third stepped shaft (4) are tightened, the hydraulic piston (43) is coaxially clamped between the first buffer ring (5) and the second buffer ring (12), and the first buffer ring (5) is clamped between the first stepped shaft (1) and the first piston ring (6). The first piston ring (6) has a strain gauge mounting groove (45) on the side near the second piston ring (8), and an annular pressure strain gauge is provided in the strain gauge mounting groove (45). The end of the second piston ring (8) near the first piston ring (6) presses against the annular pressure strain gauge.

2. The cylindrical hydraulic cylinder with a combined piston structure according to claim 1, characterized in that: The second buffer ring (12) has an internal threaded hole (11) that runs through the wall in the radial direction. A locking screw (17) is threaded in the internal threaded hole (11). A copper washer (16) is provided at the bottom of the internal threaded hole (11). When the locking screw (17) is tightened, the copper washer (16) presses tightly against the external thread of the third stepped shaft (4), thereby locking the second buffer ring (12).

3. A cylindrical hydraulic cylinder with a combined piston structure according to claim 2, characterized in that: The second stepped shaft (13) is provided with a first annular groove (2) and a second annular groove (3) respectively. The sealing rings in the first annular groove (2) and the second annular groove (3) respectively seal with the inner rings of the first piston ring (6) and the second piston ring (8).

4. A cylindrical hydraulic cylinder with a combined piston structure according to claim 3, characterized in that: The outer rings of the first piston ring (6) and the second piston ring (8) are respectively provided with a first wear-resistant ring groove (7) and a second wear-resistant ring groove (9), and a first wear-resistant sealing ring (19) and a second wear-resistant sealing ring (20) are respectively provided in the first wear-resistant ring groove (7) and the second wear-resistant ring groove (9).

5. A cylindrical hydraulic cylinder with a combined piston structure according to claim 4, characterized in that: It also includes a stroke positioning pin on a fixed end cap at one end of a hydraulic cylinder tube (18) that is coaxially threaded to the threaded section (14).

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