A self-filtering oil cylinder

Abstract

The present invention belongs to the technical field of hydraulic cylinders, and in particular, relates to a self-filtering oil cylinder, comprising a cylinder body, an inner chamber and an outer chamber are arranged in the cylinder body, a first pressure block is slidably arranged at the bottom end of the rodless chamber of the inner chamber, a connecting portion is extended at the bottom end of the first pressure block, and a first return spring is connected between the connecting portion and the bottom cover; comprising an annular filter cartridge, an annular valve block is connected to the upper and lower ends of the annular filter cartridge, a first annular groove and a first oil inlet channel are arranged on the outer wall of the annular valve block, and the oil outlet end of the first oil inlet channel is connected to the annular filter cartridge; a second annular groove and a third annular groove are arranged on the inner walls of the upper and lower ends of the outer chamber, respectively, and the second annular groove and the third annular groove at each end are connected through a plurality of second oil inlet channels. In the present invention, the piston structure and the filter structure are designed in linkage, and the filter structure is controlled to open / close the filter by the movement of the oil cylinder, and the cylinder body and the filter mechanism are designed in an integrated manner. The overall structure is simple and ingenious, and there is no need to design other valve body switch structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic cylinders, and in particular relates to a self-filtering cylinder. Background Art

[0002] The cylinder is the most important component of construction machinery. The cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy and makes a linear reciprocating motion. The medium required for the cylinder to transmit kinetic energy is hydraulic oil. In order to ensure the normal operation of hydraulic components, the existing hydraulic cylinders are designed with a structure for filtering impurities in the medium (hydraulic oil), so as to avoid problems such as damage to the internal sealing performance of the cylinder caused by impurities, scratching of the inner wall of the cylinder body, and thus affecting normal use.

[0003] In the prior art, cylinders generally do not have a self-filtering function. The filtering structure is arranged outside the cylinder and connected to the cylinder to play a filtering role. For example, the Chinese invention patent with the publication number CN113417912A discloses an oil filtering and cooling device for a hydraulic cylinder, and the filtering structure is arranged outside the cylinder. However, the connection between this filtering mechanism and the cylinder is not compact enough, occupying space and not being suitable for use in some occasions.

[0004] For example, the Chinese invention patent with the publication number CN212028225U discloses a self-filtering cylinder, which integrates the filtering structure on the cylinder body, including a cylinder body of the cylinder, a front end cover and a rear end cover are respectively arranged at both ends of the cylinder body, a piston rod is movably connected inside the cylinder body, an oil inlet and an oil outlet are opened on the outer side wall of the cylinder body, and filter meshes are embedded at the oil inlet and the oil outlet. For self-filtering cylinders, most of the filtering structures are designed similarly to the above, and the filtering structure is arranged at the inlet and outlet ports to achieve impurity filtration. However, this filtering structure can only block impurities at the inlet and outlet ports. Due to the limited telescopic stroke of the hydraulic cylinder, especially in a long pipeline hydraulic system, the hydraulic oil and impurities at the cylinder position move back and forth to rub against the pipeline and the filtering structure, and cannot circulate back to the hydraulic station, so the impurities cannot be taken back to the hydraulic station for filtration and removal, resulting in some impurities always staying on the pipeline outside the inlet and outlet ports. As time goes by, more and more impurities accumulate, which is likely to cause the filtering mechanism to fail, and then enter the cylinder body to damage the internal seal of the cylinder body, resulting in the failure of the hydraulic cylinder. Summary of the Invention

[0005] The present invention provides a self-filtering cylinder to solve the problems in the prior art that the connection between the filtering mechanism of non-self-filtering cylinders and the cylinder is not compact enough, occupying space and not being suitable for use in many occasions; and the filtering structure of self-filtering cylinders cannot collect impurities, and the impurities circulate back and forth in the pipeline near the inlet and outlet ports along with the hydraulic oil, resulting in the failure of the filtering mechanism.

[0006] To achieve the above object, the technical solution provided by the present invention is as follows:

[0007] A self-filtering oil cylinder, comprising a cylinder block and a bottom cover. An inner cavity and an outer cavity are provided inside the cylinder block. The inner cavity is a cylindrical cavity, and a piston and a piston rod mechanism are slidably arranged on its inner wall. The outer cavity is an annular cavity surrounding the outside of the inner cavity, and a filtering mechanism is slidably arranged inside it. The bottom end of the rodless cavity of the cylinder block is detachably provided with a bottom cover. The bottom end of the rodless cavity of the inner cavity is slidably provided with a first pressing block. A connecting portion extends from the bottom end of the first pressing block and extends out of the bottom end of the cylinder block into the inner cavity of the bottom cover. A first return spring is connected between the connecting portion and the bottom cover. The filtering mechanism includes an annular filter cylinder. The upper and lower ends of the annular filter cylinder are respectively connected with annular valve blocks. A first annular groove is provided on the outer wall of the annular valve block. A plurality of first oil inlet channels communicating with the first annular groove are evenly distributed around the circumference of the annular valve block. The oil outlet end of the first oil inlet channel communicates with the annular filter cylinder. Second annular grooves and third annular grooves are respectively arranged at intervals on the inner walls of the upper and lower ends of the outer cavity. Each second annular groove and third annular groove at each end are communicated through a plurality of second oil inlet channels. A first sliding rod is arranged at the bottom end of the annular valve block on the side of the rodless cavity. One end of the first sliding rod extends into the inner cavity of the bottom cover and is connected with the connecting portion. When the piston and the piston rod mechanism expand and contract, the first annular groove and the second annular groove are staggered from each other and in a closed state. When the piston and the piston rod mechanism contract and press the first pressing block, the first annular groove and the second annular groove are docked and communicated and in an open state.

[0008] The present invention has the following advantages and beneficial effects:

[0009] First, in the present invention, the cylinder block is provided with an inner and an outer double cavity, and the filtering structure is slidably arranged in the outer cavity. Further, the cylinder block and the filtering mechanism are integrally and compactly designed, reducing space occupation and expanding the usage scenarios.

[0010] Second, in the present invention, the piston and the filtering structure inside the cylinder body are designed to be linked. The filtering structure includes an annular filter cartridge and annular valve blocks provided at both ends of the annular filter cartridge. By controlling the sliding of the entire filtering structure, the communication between the annular valve block and the outer chamber is closed. When the piston and the piston rod mechanism expand and contract, the reversing valve block and the outer chamber are in a closed state. At this time, the piston rod moves normally, and the hydraulic oil cannot enter the annular filter cartridge for filtering. When the piston and the piston rod mechanism contract and press the first pressing block, the first pressing block moves to drive the filtering structure to move, realizing the communication between the reversing valve block and the outer chamber, so that the hydraulic oil enters the filter cartridge for filtering, and the filtered impurities remain in the annular filter cartridge. The present invention realizes filtering by opening or closing the annular valve block through the movement of the piston and the piston rod itself, without the need to additionally provide other valve body switch structures. The structure is ingenious, further simplifying the internal structure of the cylinder body, especially the switch control of the filtering structure. When the filter cartridge is opened, the impurities can be effectively collected in the annular filter cartridge. After the filter cartridge is closed, the impurities cannot flow back out of the annular filter cartridge. Moreover, the first pressing block is arranged on the side of the rodless cavity, and the piston only opens the filter when it contracts to the limit position. Since the hydraulic pipe is generally not stressed and does not bear pressure when contracting, that is, it is not in a working state, the problem of cylinder body pressure relief does not need to be considered at this time, and the piston rod can maintain pressure when extending. The reasonable design of the present invention enables the hydraulic cylinder to work normally and realize filtering. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is the front view of the self-filtering oil cylinder provided by the first embodiment of the present invention;

[0012] Figure 2 is Figure 1 the partial enlarged view at a in

[0013] Figure 3 is Figure 1 the partial enlarged view at b in

[0014] Figure 4 is the schematic diagram of the annular valve block on the side of the rodless cavity being in an open state after the piston provided by the first embodiment of the present invention contracts;

[0015] Figure 5 is the schematic diagram of the annular valve block on the side of the rodless cavity being in an open state after the piston provided by the first embodiment of the present invention contracts;

[0016] Figure 6 is the schematic diagram of the filtering mechanism provided by the first embodiment of the present invention;

[0017] Figure 7 is the cross-sectional view of the diversion component provided by the first embodiment of the present invention;

[0018] Figure 8 is Figure 7 the partial enlarged view at c in

[0019] Figure 9 A cross-sectional view of the filtering mechanism provided in the first embodiment of the present invention;

[0020] Figure 10 A connection structure diagram of the annular valve block and the annular slider provided in the first embodiment of the present invention;

[0021] Figure 11 A connection structure diagram of the annular valve block and the first pressing block provided in the first embodiment of the present invention;

[0022] Figure 12 A cross-sectional view of the connection between the pipe body and the flow blocking member provided in the first embodiment of the present invention;

[0023] Figure 13 A cross-sectional view of the flow blocking member provided in the first embodiment of the present invention;

[0024] Figure 14 A front view of the self-filtering oil cylinder provided in the second embodiment of the present invention;

[0025] Figure 15 is Figure 14 A partial enlarged view at position d in

[0026] Figure 16 is Figure 14 A partial enlarged view at position e in

[0027] Figure 17 A cross-sectional view of the filtering mechanism provided in the second embodiment of the present invention;

[0028] Figure 18 A connection structure diagram of the annular valve block and the second pressing block provided in the second embodiment of the present invention;

[0029] Figure 19 A schematic diagram showing the open state of the annular valve block on the rodless cavity side after the piston extends in the second embodiment of the present invention;

[0030] Figure 20 A schematic diagram showing the open state of the annular valve block on the rodless cavity side after the piston extends in the second embodiment of the present invention;

[0031] Icons: 1 - cylinder block, 1a - inner cavity, 1b - outer cavity, 11 - second ring groove, 12 - second oil inlet passage, 13 - oil inlet and outlet passage, 2 - piston and piston rod mechanism, 3 - upper cover, 31 - second cavity, 4 - oil pipe joint, 4a - inlet side, 4b - outlet side, 4c - accommodating cavity, 41 - pipe body, 411 - oil hole, 412 - stepped ring groove, 42 - flow blocking member, 421 - first conical filter screen, 4211 - fixing part, 4212 - cross bar, 4213 - second annular notch, 422 - second conical filter screen, 4221 - supporting part, 4222 - supporting rod, 5 - second fixing screw, 51 - second return spring, 52 - annular slider, 521 - guiding hole, 53 - second sliding rod, 54 - third sliding rod, 55 - second pressing block, 551 - second through hole, 6 - bottom cover, 61 - first cavity, 7 - first fixing screw, 71 - first return spring, 72 - connecting part, 73 - first pressing block, 731 - first through hole, 74 - first connecting rod, 75 - first sliding rod, 8 - annular filter cartridge, 81 - outer cylinder, 811 - outer cylinder annular cavity, 82 - inner cylinder, 821 - inner cylinder annular cavity, 9 - annular valve block, 91 - first ring groove, 92 - first oil inlet passage, 10 - diversion assembly, 101 - upper ring, 1011 - first annular oil cavity, 1012 - first annular notch, 102 - lower ring, 1021 - second annular oil cavity. Detailed implementation mode

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0034] Embodiment 1

[0035] As Figure 1 shown, a self-filtering oil cylinder includes a cylinder block 1, an upper cover 3, and a bottom cover 6. An inner cavity 1a and an outer cavity 1b are provided in the cylinder block 1. Oil inlet and outlet passages 13 are respectively arranged at the upper and lower ends of the inner cavity 1a. The inner cavity 1a is a cylindrical cavity, and a piston and piston rod mechanism 2 is slidably arranged on its inner wall; the outer cavity 1b is an annular cavity surrounding the outside of the inner cavity 1a, and a filtering mechanism is slidably arranged inside it. The filtering mechanism is arranged in the cylinder block 1 for further integrated design.

[0036] An oil pipe joint 4 is respectively arranged on the upper cover 3 and the bottom cover 6, and the two oil pipe joints 4 are respectively communicated with the upper and lower ends of the inner cavity 1a and the outer cavity 1b. When the piston and piston rod mechanism 2 rises, the oil pipe joint 4 on the bottom cover 6 intakes oil; when the piston and piston rod mechanism 2 descends, the oil pipe joint 4 on the upper cover 3 intakes oil.

[0037] As Figure 1 , Figure 3 , Figure 11 shown, the bottom end of the rodless cavity of the cylinder block 1 is detachably provided with a bottom cover 6, a first cavity 61 is arranged inside the bottom cover 6, a ring-shaped first pressing block 73 is slidably arranged at the bottom end of the rodless cavity of the inner cavity 1a, the first pressing block 73 slides closely along the inner cavity 1a, and a number of first through holes 731 are evenly distributed on the circumference of the first pressing block 73 for the normal flow of hydraulic oil. A connecting portion 72 is extended at the bottom end of the first pressing block 73, and the connecting portion 72 extends from the bottom end of the cylinder block 1 into the first cavity 61. A first fixing screw 7 is threadedly connected to the bottom cover 6, and a guiding portion is extended at the end of the first fixing screw 7. The guiding portion extends into the inner cavity of the connecting portion 72 to conduct sliding guidance on the connecting portion 72. A first return spring 71 is sleeved on the guiding portion between the connecting portion 72 and the first fixing screw 7.

[0038] As Figures 1-3 , Figures 6-9 , Figure 11 shown, the filtering mechanism includes an annular filter cartridge 8. Upper and lower ends of the annular filter cartridge 8 are respectively connected with an annular valve block 9. The annular filter cartridge 8 and the annular valve block 9 are integrally connected and slide synchronously inside the outer cavity 1b. A first annular groove 91 is arranged on the outer wall of the annular valve block 9, and a number of first oil inlet channels 92 communicated with the first annular groove 91 are evenly distributed on the circumference of the annular valve block 9. The oil outlet end of the first oil inlet channel 92 is communicated with the annular filter cartridge 8; two second annular grooves 11 are respectively arranged at intervals on the inner walls of the upper and lower ends of the outer cavity 1b, and the two second annular grooves 11 at each end are communicated through a number of second oil inlet channels 12; three first sliding rods 75 are evenly distributed on the circumference of the bottom end of the annular valve block 9 on the side of the rodless cavity. One end of the first sliding rod 75 extends into the first cavity 61 and is connected with the connecting portion 72 through a first connecting rod 74.

[0039] As Figure 2 , Figure 3 shown, when the piston and piston rod mechanism 2 expands and contracts, the first annular groove 91 and the second annular groove 11 are staggered and in a closed state. Figure 2 In Figure 3 , the first annular groove 91 is between the two second annular grooves 11 and staggered;

[0040] InFigure 4 , Figure 5 As shown, when the piston and piston rod mechanism 2 contract and push the first pressure block 73, the first return spring 71 is compressed, and the first pressure block 73 slides to the bottom end of the inner chamber 1a, synchronously driving the annular valve block 9 and the filter cartridge as a whole to move downward in the outer chamber 1b, so that the first annular groove 91 and the second annular groove 11 are connected and are in an open state. Figure 4 In the embodiment, the second annular groove 11 away from the upper cover 3 is connected to the first annular groove 91; Figure 5 In the embodiment, the second annular groove 11 away from the bottom cover 6 is connected to the first annular groove 91, so that the outer chamber 1b is connected to the annular filter cartridge 8. After the connection, the hydraulic oil enters from the oil pipe joint 4 of the upper cover 3, reaches the outer chamber 1b, passes through the annular valve block 9, the annular filter cartridge 8, and the annular valve block 9 from top to bottom, and finally exits from the oil pipe joint 4 of the bottom cover 6, and the impurities are filtered in the annular filter cartridge 8. When the piston and the piston rod mechanism 2 extend upward, the first reset spring 71 resets and pushes the first pressure block 73 to reset, the filter cartridge and the annular valve block 9 reset and close, and the filter cartridge stops filtering.

[0041] The piston and the filtering structure in the cylinder body 1 of the present invention are designed to be linked. The annular valve block 9 is opened or closed by the movement of the piston and the piston rod itself to achieve filtering. There is no need to set up other valve body switch structures. The structure is ingenious and further simplifies the internal structure of the cylinder body 1, especially the switch control of the filtering structure. When the filter cartridge is opened, impurities can be effectively collected in the annular filter cartridge 8. After the filter cartridge is closed, impurities cannot flow back out of the annular filter cartridge 8. In addition, the first pressure block 73 is arranged on one side of the rodless cavity. The piston starts filtering only when it is retracted to the extreme position. Since the hydraulic cylinder is generally not subjected to force to bear pressure when it is retracted, that is, it is not in a working state, there is no need to consider the pressure relief problem of the cylinder body 1 at this time, and the piston rod can maintain pressure when extended.

[0042] like Figure 2 , Figure 10As shown in the figure, as a further design of the present invention, a top cover 3 is detachably arranged at the top end of the rod chamber of the cylinder block 1. A second cavity 31 is arranged inside the top cover 3. An annular slider 52 with a notch is arranged in the second cavity 31. The notch is the installation position of components such as the top cover 3 and the oil pipe joint 4. The shape of the second cavity 31 corresponds to that of the annular slider 52. The inner wall of the annular slider 52 is slidably arranged in the inner wall of the second cavity 31. Three second sliding rods 53 are evenly arranged at the bottom end of the annular slider 52. One end of each second sliding rod 53 extends into the outer chamber 1b and is connected to the annular valve block 9 on one side of the rodless chamber. Three guiding holes 521 are arranged at the upper end of the annular slider 52. Three second fixing screws 5 are threadedly connected to the top cover 3. A guiding portion is arranged at the end of each second fixing screw 5 and extends into the guiding hole 521. A second return spring 51 is sleeved on the guiding portion between the annular slider 52 and the second fixing screw 5. When the piston and piston rod mechanism 2 contracts to push the first pressing block 73, the first return spring 71 is compressed, and the second return spring 51 is stretched. The elastic force is further enhanced through the second return spring 51, so as to increase the reset ability of the first pressing block 73. At the same time, by designing the above structure, the limit precision of the sliding guide of the filtering mechanism is further strengthened.

[0043] As Figures 6-9 shown in the figure, in the present invention, a further design is also made for the annular filter cartridge 8. Among them, the annular filter cartridge 8 includes an outer cylinder 81 and an inner cylinder 82. The filter screen diameters of the outer cylinder 81 and the inner cylinder 82 allow hydraulic oil to pass through, and impurities cannot pass through. An annular cavity is formed between the outer cylinder 81 and the inner cylinder 82. An annular opening is arranged at the upper end of the annular cavity, and the opening end is located on the side of the rod chamber. A plurality of annular diversion components 10 are sequentially connected end to end and placed through the opening. The diversion component 10 includes an upper ring 101 and a lower ring 102 arranged oppositely. The cross-section of the upper ring 101 is in an inverted cone shape, and an inverted conical first annular oil cavity 1011 is arranged inside. The cross-section of the lower ring 102 is in a positive cone shape, and a positive conical second annular oil cavity 1021 is arranged inside. A first annular notch 1012 is arranged at the conical tip of the upper ring 101. The conical tip of the lower ring 102 is arranged in the first annular notch 1012, and the upper ring 101 and the lower ring 102 are fixed into one body. After the diversion component 10 is installed in the annular cavity, the upper ring 101, the lower ring 102, the inner cylinder 82 and the outer cylinder 81 form an inner cylinder ring cavity 821 and an outer cylinder ring cavity 811.

[0044] The filter screen diameter of the upper ring 101 only allows hydraulic oil to pass through, and impurities cannot pass through. The impurities can only reach the surface of the lower ring 102 through the first annular notch 1012, that is, reach the inner cylinder ring cavity 821 and the outer cylinder ring cavity 811. The lower ring 102 is divided into a conical tip section L1 and a conical flared section L2. The filter screen diameter of the conical tip section L1 only allows hydraulic oil to pass through, and the filter screen diameter of the conical flared section L2 allows hydraulic oil and large particle impurities to pass through. Therefore, the impurities reaching the inner cylinder ring cavity 821 and the outer cylinder ring cavity 811 will continue to reach the first annular oil cavity 1011 of the next upper ring 101 along with the hydraulic oil through the conical flared section L2, and flow in this order until the impurities are all washed to the bottom end of the filter cartridge; at the same time, with such a design, it is almost impossible for impurities to flow back. When flowing back, the impurities will gather in the inner cavity of the conical tip section L1 (that is, the narrow part cavity in the second annular oil cavity 1021). And if some impurities flow back through the conical flared section L2, they will reach the inner cylinder ring cavity 821 and the outer cylinder ring cavity 811 and cannot flow back through the upper ring 101. Only a very small part of the impurities can flow back through the first annular notch 1012. However, the design of the multiple guide components 10 connected end to end in sequence further limits this backflow, so as to ensure that the impurities are collected inside the filter cartridge.

[0045] In the present invention, by designing the shapes and filter screen diameters of the upper ring 101 and the lower ring 102, the hydraulic oil and impurities are drained and separated, so that the hydraulic oil flows to the filter cartridge for filtration, and the impurities cannot flow out reversely and are always collected and filtered inside the filter cartridge. Therefore, the design of this structure is not likely to cause the hydraulic oil to flow back and wash out the impurities from the filter cartridge. So there is no requirement for the installation position of the oil cylinder, which greatly enhances the collection effect of the filter cartridge and avoids the problem that the filter mechanism fails due to the impurities accompanying the hydraulic oil to circulate back and forth in the pipelines near the oil inlet and outlet.

[0046] Filtration principle: As Figure 9 shown, when the piston and piston rod mechanism 2 contracts and pushes the first pressing block 73 to the bottommost position, it synchronously drives the annular valve block 9 and the filter cartridge as a whole to move downward in the outer chamber 1b, so that the first ring groove 91 and the second ring groove 11 are butted and communicated in an open state. At this time, the oil inlet of the oil pipe joint 4 on the upper cover 3 reaches the outer chamber 1b, then enters the first ring groove 91 of the annular valve block 9 on the side of the rodless cavity through the second ring groove 11, and then enters the guide component 10 through the first oil inlet passage 92. The hydraulic oil passes through multiple guide components 10 in sequence and then reaches the first ring groove 91 of the annular valve block 9 on the side of the rodless cavity, then returns to the bottom end of the outer chamber 1b through the second ring groove 11, and then flows out from the oil pipe joint 4 of the bottom cover 6 to form a circulating oil circuit.

[0047] As Figure 12 and 13As shown in the figure, in the present invention, the oil pipe joint 4 includes a pipe body 41 and a flow blocking member 42 disposed within the pipe body 41. The structural principle of the flow blocking member 42 is similar to that of the diversion assembly 10. Through the conical structure setting, it plays a role in preventing impurities from entering the inner cavity 1a, while adsorbing and collecting the impurities. When the filter mechanism filters, the impurities in the flow blocking member 42 are flushed into the filter cartridge for collection, further improving the collection effect, preventing impurities from staying on the oil inlet and return paths, and ensuring the cleanliness of the oil path.

[0048] The flow blocking member 42 includes a first conical filter screen 421 and a second conical filter screen 422 which are oppositely arranged. A second annular notch 4213 is provided at the tip of the first conical filter screen 421, and the tip of the second conical filter screen 422 is disposed in the second annular notch 4213. The first conical filter screen 421 is located at the inlet side 4a of the pipe body 41, and the outlet side 4b of the pipe body 41 is communicated with the inner cavity 1a. An annular accommodation cavity 4c is formed between the first conical filter screen 421, the first conical filter screen 421 and the pipe body 41. A plurality of oil holes 411 are provided on the inner wall of the accommodation cavity 4c, and the oil holes 411 are communicated with the outer cavity 1b. A support portion 4221 is provided at the bottom end of the second conical filter screen 422, a fixing portion 4211 is provided at the top end of the first conical filter screen 421, and the fixing portion 4211 is clamped on the stepped annular groove 412 within the pipe body 41. A support rod 4222 is provided at the tip of the second conical filter screen 422, and the end of the support rod 4222 is connected to the fixing portion 4211 through a plurality of cross bars 4212, so that the first conical filter screen 421 and the second conical filter screen 422 form an integral body and are detachably fixed within the pipe body 41. The filter screen diameters of the first conical filter screen 421 and the second conical filter screen 422 only allow hydraulic oil to pass through, and impurities can only enter the accommodation cavity 4c through the second annular notch 4213. When the piston moves in a telescopic motion with the piston rod structure 2, the hydraulic oil flows from the inlet side 4a to the outlet side 4b and reaches the inner cavity 1a, and the hydraulic oil cannot enter the outer cavity 1b through the oil holes 411. At this time, the impurities stay in the accommodation cavity 4c, playing the role of filtering and collecting impurities on the oil inlet side; when the piston contracts to the bottom end with the piston rod structure 2 and the annular valve block 9 is in the open state, the hydraulic oil flows from the inlet side 4a to the oil holes 411 and reaches the outer cavity 1b, and at the same time drives the impurities in the accommodation cavity 4c to flow into the inner part of the annular filter cartridge 8, realizing the further collection and cleaning of the impurities, and avoiding the problems of impurity aggregation on the inlet and outlet sides of the oil and the damage of the filtering components caused by the scouring of the hydraulic oil circulating flow.

[0049] Embodiment 2

[0050] In the second embodiment of the present invention, it is further defined that:

[0051] Such as Figures 14-16 、 Figure 18As shown, a second pressing block 55 is slidably arranged at the bottom end of the rodless cavity of the inner cavity 1a. The second pressing block 55 is closely attached to the inner cavity 1a. A number of second through holes 551 are evenly distributed around the circumference of the second pressing block 55 for the circulation of hydraulic oil. Three third sliding rods 54 are evenly distributed at the bottom end of the annular slider 52. One end of each third sliding rod 54 extends into the inner cavity 1a and is connected to the second pressing block 55. In this embodiment, the number of the first annular grooves 91 on the outer wall of the annular valve block 9 is set to two. Both of the two first annular grooves 91 are communicated with the first oil inlet passage 92.

[0052] When the piston and piston rod mechanism 2 expands and contracts, the first annular groove 91 and the second annular groove 11 are staggered from each other and in a closed state. As Figure 15 shown, the second annular groove 11 far from the upper cover 3 is located between the two first annular grooves 91, and the first annular groove 91 far from the annular filter cartridge 8 is located between the two second annular grooves 11. The four annular grooves are staggered from each other, and the annular valve block 9 is in a closed state; in Figure 16 , the second annular groove 11 far from the bottom cover 6 is located between the two first annular grooves 91, and the first annular groove 91 far from the annular filter cartridge 8 is located between the two second annular grooves 11. The four annular grooves are staggered from each other, and the annular valve block 9 is in a closed state.

[0053] The communication state when the piston and piston rod mechanism 2 contracts and presses the first pressing block 73 is the same as that in Embodiment 1, and reference can be made to Figure 4 and Figure 5 . When the piston and piston rod mechanism 2 extends to the limit position and presses the second pressing block 55, the first return spring 71 is stretched, and the second return spring 51 is compressed. The second pressing block 55 slides to the top end of the inner cavity 1a, synchronously driving the annular valve block 9 and the filter cartridge as a whole to move upward in the outer cavity 1b, so that the first annular groove 91 and the second annular groove 11 are docked and communicated and in an open state.

[0054] Figure 19 In, the second annular groove 11 far from the upper cover 3 and the first annular groove 91 close to the annular filter cartridge 8 are docked and communicated; Figure 20 In, the second annular groove 11 far from the bottom cover 6 and the first annular groove 91 far from the annular filter cartridge 8 are docked and communicated, so that the outer cavity 1b and the annular filter cartridge 8 are communicated. After being communicated, the hydraulic oil enters through the oil pipe joint 4 on the bottom cover 6, reaches the outer cavity 1b, passes through the annular valve block 9, the annular filter cartridge 8, and the annular valve block 9 in sequence from bottom to top, and finally exits through the oil pipe joint 4 on the upper cover 3. The impurities are filtered in the annular filter cartridge 8. When the piston and piston rod mechanism 2 contracts, the first return spring 71 and the second return spring 51 reset to push the second pressing block 55 to reset, and the annular filter cartridge 8 and the annular valve block 9 reset and close, and the filter cartridge stops filtering.

[0055] In this way, whether the annular valve block 9 rises or falls, the outer chamber 1b can be connected to realize the filtration of the annular filter cartridge 8. That is, in addition to the case where the piston and piston rod mechanism 2 contracts to push the first pressing block 73 and the movement drives the annular valve block 9 to open to realize the filtration of the annular filter cartridge 8, the annular valve block 9 can also be driven to open by the piston and piston rod mechanism 2 extending to push the second pressing block 55 to realize filtration. Such a design can realize the two-way flushing and filtration of the oil inlet and return oil circuits, further enhancing the filtration effect. However, since the oil cylinder is generally in a compressed working state when it extends, when the oil cylinder extends to the maximum stroke end, pressure relief will occur when the filtration is opened. Therefore, in such a case, the working stroke of the oil cylinder can only be in the middle section, and when the oil cylinder is fully contracted or fully extended, it is in the filtration state.

[0056] The present invention realizes the function of two-way filtration. In order to ensure that the impurities filtered in both directions can remain in the filter cartridge, the inner wall structure of the annular filter cartridge 8 is further optimized. The structural design of the annular filter cartridge 8 is basically the same as that in Embodiment 1, and the only difference is the installation position of the diversion assembly 10 and the upper and lower ends of the annular filter cartridge 8 are both open.

[0057] As Figure 17 shown, an annular cavity is formed between the outer cylinder 81 and the inner cylinder 82. Annular openings are provided at both ends of the annular cavity. A plurality of annular diversion assemblies 10 are arranged opposite to each other up and down in the annular cavity. By designing the shapes of the upper ring 101 and the lower ring 102 and the diameter of the filter screen, and arranging a plurality of diversion assemblies 10 opposite to each other inside the filter cartridge, the hydraulic oil can achieve the filtration effect whether it enters from the lower end or the upper end, and the impurities are not easily washed out of the filter cartridge. That is, the cyclic flushing movement of the hydraulic oil will not cause the impurities inside the annular filter cartridge 8 to be washed out of the annular filter cartridge 8. Coupled with the design of the flow blocking member 42 in the oil pipe joint 4, the backflow of impurities is further prevented, and the impurities can be effectively retained in the filter cartridge for collection, avoiding the situation that the oil inlet and return oil circuits are filled with impurities, and the impurities continuously wash the pipe body 41 and the filter assembly during the piston expansion and contraction process, resulting in filtration failure and the impurities entering the inner cavity 1a and damaging the seal.

[0058] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A self-filtering oil cylinder, comprising a cylinder block and a bottom cover. An inner cavity and an outer cavity are provided inside the cylinder block. The inner cavity is a cylindrical cavity, and a piston and a piston rod mechanism are slidably arranged on its inner wall. The outer cavity is an annular cavity surrounding the outside of the inner cavity, and a filtering mechanism is slidably arranged inside it, characterized in that : A bottom cover is detachably provided at the bottom end of the rodless cavity of the cylinder block. A first pressing block is slidably arranged at the bottom end of the rodless cavity of the inner cavity. A connecting portion extends from the bottom end of the first pressing block and protrudes from the bottom end of the cylinder block into the inner cavity of the bottom cover. A first return spring is connected between the connecting portion and the bottom cover. The filtering mechanism includes an annular filter cartridge. Annular valve blocks are respectively connected to the upper and lower ends of the annular filter cartridge. A first annular groove is provided on the outer wall of the annular valve block. A plurality of first oil inlet channels communicating with the first annular groove are evenly distributed around the circumference of the annular valve block. The oil outlet end of the first oil inlet channel communicates with the annular filter cartridge. Second annular grooves are respectively arranged at intervals on the inner walls of the upper and lower ends of the outer cavity. The two second annular grooves at each end are communicated through a plurality of second oil inlet channels. A first sliding rod is provided at the bottom end of the annular valve block on the rodless cavity side. One end of the first sliding rod extends into the inner cavity of the bottom cover and is connected to the connecting portion. When the piston and piston rod mechanism expands and contracts, the first annular groove and the second annular groove are staggered from each other and in a closed state. When the piston and piston rod mechanism contracts and presses the first pressing block, the first annular groove and the second annular groove are docked and communicated and in an open state. An upper cover is detachably provided at the top end of the rod cavity of the cylinder block. An annular sliding block with a notch is arranged in the inner cavity of the upper cover. A second sliding rod is provided at the bottom end of the annular sliding block. One end of the second sliding rod extends into the outer cavity and is connected to the annular valve block on the rodless cavity side. A second return spring is connected between the annular sliding block and the upper cover. A second pressing block is slidably arranged at the bottom end of the rod cavity of the inner cavity. A third sliding rod is provided at the bottom end of the annular sliding block. One end of the third sliding rod extends into the inner cavity and is connected to the second pressing block. The number of the first annular grooves provided on the outer wall of each annular valve block is two. When the piston and piston rod mechanism expands and contracts, the first annular groove and the second annular groove are staggered from each other and in a closed state. When the piston and piston rod mechanism extends and presses the second pressing block, the first annular groove and the second annular groove are docked and communicated and in an open state.

2. The self-filtering oil cylinder according to claim 1, characterized in that: The annular filter cartridge includes an outer cylinder and an inner cylinder. The filter screen diameters of the outer cylinder and the inner cylinder allow hydraulic oil to pass through. An annular cavity is formed between the outer cylinder and the inner cylinder. An annular opening is provided at the upper end of the annular cavity, and the opening end is located on the rod cavity side. A plurality of annular flow guiding components connected end to end are sequentially placed through the opening. The flow guiding component includes an upper ring and a lower ring arranged oppositely. The cross section of the upper ring is in an inverted cone shape, and an inverted conical first annular oil cavity is arranged inside. The cross section of the lower ring is in a positive cone shape, and a positive conical second annular oil cavity is arranged inside. A first annular notch is provided at the conical tip of the upper ring. The conical tip of the lower ring is arranged in the first annular notch. The filter screen diameter of the upper ring only allows hydraulic oil to pass through. The lower ring is divided into a conical tip section L1 and a conical flared section L2. The filter screen diameter of the conical tip section L1 only allows hydraulic oil to pass through. The filter screen diameter of the conical flared section L2 allows hydraulic oil and large particle impurities to pass through.

3. The self-filtering oil cylinder according to claim 1, characterized in that: The annular filter cartridge includes an outer cylinder and an inner cylinder, and the filter screen diameters of the outer cylinder and the inner cylinder allow hydraulic oil to pass through; an annular cavity is formed between the outer cylinder and the inner cylinder, and annular openings are provided at both ends of the annular cavity, and a plurality of annular flow guiding components are arranged oppositely up and down in the annular cavity; the flow guiding component includes an upper ring and a lower ring arranged oppositely, and the upper ring is arranged on the opening side of the annular cavity, the cross section of the upper ring is in an inverted cone shape, and an inverted conical first annular oil cavity is arranged inside, the cross section of the lower ring is in a positive cone shape, and a positive conical second annular oil cavity is arranged inside; a first annular notch is arranged at the conical tip of the upper ring, and the conical tip of the lower ring is arranged in the first annular notch; the filter screen diameter of the upper ring only allows hydraulic oil to pass through, the lower ring is divided into a conical tip section L1 and a conical flared section L2, the filter screen diameter of the conical tip section L1 only allows hydraulic oil to pass through, and the filter screen diameter of the conical flared section L2 allows hydraulic oil and large particle impurities to pass through.

4. The self-filtering oil cylinder according to claim 2 or 3, characterized in that: Oil pipe joints are respectively arranged on the upper cover and the bottom cover, and the two oil pipe joints are respectively communicated with the upper and lower ends of the inner cavity and the outer cavity.

5. The self-filtering oil cylinder according to claim 4, characterized in that: The oil pipe joint includes a pipe body and a flow blocking member placed in the pipe body. The flow blocking member includes a first conical filter screen and a second conical filter screen arranged oppositely. A second annular notch is arranged at the tip of the first conical filter screen, and the tip of the second conical filter screen is arranged in the second annular notch. The first conical filter screen is on the inlet side of the pipe body, and the outlet side of the pipe body is communicated with the inner cavity; an annular accommodating cavity is formed between the first conical filter screen, the first conical filter screen and the pipe body, and a plurality of oil holes are arranged on the inner wall of the accommodating cavity, and the oil holes are communicated with the outer cavity; the filter screen diameters of the first conical filter screen and the second conical filter screen only allow hydraulic oil to pass through.

6. The self-filtering oil cylinder according to claim 5, characterized in that: The first pressing block and the second pressing block are slidably arranged close to the inner cavity, and a plurality of first through holes are evenly distributed on the circumference of the first pressing block, and a plurality of second through holes are evenly distributed on the circumference of the second pressing block.

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