Anti-loose hydraulic air filter

Abstract

The utility model discloses an anti-loose hydraulic air filter, which relates to the technical field of hydraulic air filters, and comprises an oiling filter screen assembly, an air filter head assembly, a filter piece, a first sealing gasket and an anti-loose assembly, the oiling filter screen assembly is detachably connected to a top opening of an equipment oil tank so as to filter hydraulic oil injected into the oil tank; the air filter head assembly is made of a non-metal material and is provided with an air channel; the filter part is used for being detachably connected with the air filter head assembly in a sealed mode so as to filter air passing through the air channel; the first sealing gasket is arranged between the refueling filter screen assembly and the air filter head assembly; the anti-loosening assembly comprises a first rotary limiting piece and a second rotary limiting piece, the first rotary limiting piece is used for being connected with the second rotary limiting piece in a rotary limiting mode so as to limit the air filter head assembly to rotate in the unscrewing direction relative to the refueling filter screen assembly, and the anti-loosening device is simple in structure and convenient to use, effectively improves the anti-rust performance and effectively improves the anti-loosening performance.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic air filter technical field, in particular to a kind of anti-loose hydraulic air filter. BACKGROUND

[0002] In hydraulic system, air filter is important component to guarantee the normal operation of hydraulic system.The traditional air filter is generally composed of air filter head, oil filter screen (including equipment oil tank installation connecting portion).Among them, air filter head parts are mostly stamped from sheet metal, then after surface treatment process such as electroplating or paint spraying, again press-fit forming.

[0003] However, this traditional manufacturing process has many defects.On the one hand, the surface layer of sheet metal treated by electroplating or paint spraying is easy to be damaged, and there is a risk of rust, which will affect the service life and filtering effect of filter, and further negatively affect the hydraulic system.On the other hand, surface treatment process such as electroplating will cause great pollution to the environment, which does not meet the requirements of modern industry for environmental protection.In addition, many equipment applications for installing hydraulic air filter are open-air and have vibration conditions, and under such environment, the existing air filter cannot meet the increasingly improved requirements in rust-proof and anti-loose performance. SUMMARY

[0004] The utility model aims at providing a kind of anti-loose hydraulic air filter to solve the problems existing in the prior art, simple structure, convenient to use, effectively improve rust-proof performance, effectively improve anti-loose performance.

[0005] To achieve the above object, the utility model provides the following scheme:

[0006] The utility model provides an anti -looseness type hydraulic air filter, include: oil filter screen subassembly, empty filter head subassembly, filter piece, first gasket and anti -looseness subassembly, the oil filter screen subassembly is detachably connected in the top opening of equipment oil tank and part oil filter screen subassembly in top opening stretches into the oil tank to filter the hydraulic oil that injects in the oil tank, the empty filter head subassembly is made of non - metallic material, the empty filter head subassembly is provided with air passage, the empty filter head subassembly is used for with the top of oil filter screen subassembly close connection and intercommunication to make air passage with the oil tank and outside intercommunication to maintain the pressure and atmospheric pressure balance in the oil tank, filter piece is used for with the detachable sealed connection of empty filter head subassembly to filter the air of air passage, first gasket is arranged between oil filter screen subassembly and empty filter head subassembly, and rotates empty filter head subassembly can make empty filter head subassembly move to oil filter screen subassembly direction and extrude first gasket, the anti -looseness subassembly includes first rotation limit piece and second rotation limit piece, first rotation limit piece is installed in oil filter screen subassembly, second rotation limit piece is installed in empty filter head subassembly, first rotation limit piece is used for with second rotation limit piece rotation limit connection to limit empty filter head subassembly relative to oil filter screen subassembly to the direction of unscrewing rotation.

[0007] Preferably, the first rotation limit piece includes a plurality of tracks, the second rotation limit piece includes a plurality of protruding claws, the protruding claws are used for slidingly clamping in the tracks, rotating the empty filter head subassembly can make the protruding claws slide along the tracks and make the empty filter head subassembly move to the oil filter screen subassembly direction to extrude the first gasket, the tracks can limit the protruding claws from sliding to the unscrewing direction after the protruding claws slide to the position where the oil filter screen subassembly and the empty filter head subassembly are tightly connected.

[0008] Preferably, the tracks include a starting end, a guide slope section, a retreat-stop section, a positioning section, and a limiting end arranged in sequence, the limiting end is used for limiting the protruding claws from sliding out of the tracks from one end of the positioning section away from the retreat-stop section, the guide slope section is arranged in a direction from the empty filter head subassembly to the oil filter screen subassembly, the positioning section is arranged in parallel with the first gasket, and the height of the connection position between the retreat-stop section and the positioning section is higher than the height of the connection position between the retreat-stop section and the guide slope section to limit the slider from sliding into the guide slope section from the limiting end.

[0009] Preferably, the protruding claws are provided with an inclined guide surface on the side facing the tightening direction of the empty filter head subassembly.

[0010] Preferably, the oil filter assembly comprises a flange, a second gasket, a filter screen, a support skeleton and a bottom cover, the second gasket is arranged between the flange and the oil tank, the flange is provided with a plurality of mounting holes in the circumferential direction, the mounting holes are used for passing mounting screws to fixedly connect the flange and the oil tank, the flange is arranged in a first annular groove away from the air filter head assembly, the bottom cover is provided with a second annular groove, one end of the filter screen is fixedly connected to the first annular groove, and the other end is fixedly connected to the second annular groove, the support skeleton is sleeved outside the filter screen, and the two ends of the support skeleton are fixedly connected to the first annular groove and the second annular groove respectively, and each track is arranged outside the flange close to one end of the air filter head assembly.

[0011] Preferably, the flange is made of PPS material by injection molding process, and the bottom cover, the support skeleton and the filter screen are all made of stainless steel.

[0012] Preferably, the air filter head assembly comprises a cover cap and a chuck, the cover cap has a hollow cavity inside and has a reinforcing rib, the chuck is provided with a clamping plate close to one side of the cover cap, the clamping plate is used for clamping connection with the cover cap, the clamping plate is provided with a plurality of air inlet and outlet ports in the circumferential direction, the cover cap has a thin-walled cover structure to form a first inner cavity with the chuck, the chuck has a second inner cavity inside, the air inlet and outlet ports communicate with the first inner cavity, the first inner cavity communicates with the second inner cavity, the second inner cavity communicates with the inside of the filter screen, and the air inlet and outlet ports, the first inner cavity and the second inner cavity form the air channel.

[0013] Preferably, the cover cap is provided with a plurality of trapezoidal grooves, a plurality of limiting grooves and a plurality of buckle handles in the circumferential direction close to the chuck, the outer side of the circumferential edge of the clamping plate is provided with a plurality of trapezoidal bosses, a plurality of limiting bosses and a plurality of empty stops, the trapezoidal bosses are used for clamping in the trapezoidal grooves to fix the clamping plate in the axial direction, the limiting bosses are used for clamping in the limiting grooves to fix the limiting plate in the circumferential direction, and the empty stops are arranged correspondingly with the buckle handles.

[0014] Preferably, the cover cap is made of nylon material by injection molding process, and the chuck is made of PPS material by injection molding process.

[0015] Preferably, the filter piece comprises an O-shaped sealing ring, a snap ring and an air filter sheet, the flange disc is provided with an annular baffle extending to the second inner cavity at one end close to the cover, the second inner cavity is provided with a clamping groove close to the annular baffle, the top of the O-shaped sealing ring is in abutment with the annular baffle, the air filter sheet is arranged on the side of the O-shaped sealing ring away from the flange disc, and the snap ring is clamped in the clamping groove and can extrude the air filter sheet to extrude and seal the air filter sheet and the O-shaped sealing ring.

[0016] The utility model discloses relative to prior art has obtained following technical effect:

[0017] The utility model provides a kind of anti-loose hydraulic air filter, the main component of hydraulic air filter is clear, lay foundation for the description of the function of each part of the whole filter and mutual cooperation relationship subsequently, so that reader can understand the basic architecture of this filter as a whole.Dismountable connection mode facilitates the installation and replacement of oil filter screen assembly, reduces maintenance cost.The design of being inserted into oil tank can directly filter when hydraulic oil is injected into oil tank, effectively remove impurities, improve the cleanliness of the hydraulic oil into oil tank, and then guarantee the normal operation of hydraulic system, prolong equipment service life.Non-metallic material is used to solve the problem of rust of traditional metal air filter head, improve anti-rust performance.The setting of air passage provides a way for air exchange inside and outside oil tank, maintains pressure balance inside and outside oil tank, guarantees the safety of oil tank, avoids affecting the normal operation of equipment due to pressure imbalance.Dismountable sealing connection facilitates replacement of filter element, improves air filtration effect, removes dust, impurities and the like in air, prevents these substances from entering oil tank to pollute hydraulic oil, improves the working environment of hydraulic system.The first sealing gasket can play a sealing role to prevent air, dust and the like from entering oil tank.By rotating air filter head assembly to extrude sealing gasket, better sealing effect can be realized, improve sealing property, reduce leakage risk.The setting of anti-loose assembly effectively avoids loosening of air filter head assembly during equipment vibration or long-term use, ensures that the overall structure is stable and reliable, guarantees normal operation of filter, reduces leakage and other problems caused by loosening. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the following will briefly introduce the drawings needed to be used in the embodiments, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creating labor.

[0019] Figure 1 The utility model provides a kind of anti-loose hydraulic air filter's front view sectional view;

[0020] Figure 2The utility model provides a top view of the flange in the anti -looseness type hydraulic air filter,

[0021] Figure 3 The utility model provides a front view of the flange in the anti -looseness type hydraulic air filter,

[0022] Figure 4 The utility model provides a bottom view of the cover cap in the anti -looseness type hydraulic air filter,

[0023] Figure 5 For Figure 4 The section view of B-B,

[0024] Figure 6 The utility model provides a top view of the chuck in the anti -looseness type hydraulic air filter,

[0025] Figure 7 For Figure 6 The section view of A-A,

[0026] Figure 8 The utility model provides a bottom view of the chuck in the anti -looseness type hydraulic air filter,

[0027] In the drawing: 1, oil filter screen assembly;11, flange;111, mounting hole;12, second sealing gasket;13, filter screen;14, support framework;15, bottom cover;16, first annular groove;17, second annular groove;2, air filter head assembly;21, cover cap;211, reinforcing rib;212, trapezoidal recess;213, limiting recess;214, buckling handle;22, chuck;221, clamping plate;222, limiting boss;223, neutral gear;224, trapezoidal boss;225, clamping groove;226, air inlet and outlet;227, annular baffle;3, filter piece;31, O type sealing ring;32, air filter sheet;33, snap ring;4, first sealing gasket;41, semicircular convex structure;5, anti -looseness subassembly;51, track;511, starting end;512, guide slope section;513, retreat stop section;514, positioning section;515, limiting end;52, convex claw;521, guide surface;6, mounting screw. DETAILED DESCRIPTION

[0028] The technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model, and apparently, the described embodiments only are a part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skilled in the art without making creative labor belong to the scope of protection of the utility model.

[0029] The utility model discloses a hydraulic air filter of anti-loose type, to solve the above prior art problems, simple structure, convenient to use, effectively improve the rustproof performance, effectively improve the anti-loose performance.

[0030] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the utility model will be further described in detail below by combining with the drawings and specific embodiments.

[0031] The utility model provides a kind of hydraulic air filter of anti-loose type, such as Figures 1-8As shown, it comprises: a refueling filter screen assembly 1, an air filter head assembly 2, a filter element 3, a first sealing gasket 4, and an anti-loosening assembly 5. The refueling filter screen assembly 1 is detachably connected to the top opening of the equipment oil tank, and part of the refueling filter screen assembly 1 extends into the oil tank to filter the hydraulic oil injected into the oil tank. The air filter head assembly 2 is made of non-metallic material, and is provided with an air passage. The air filter head assembly 2 is used to be tightly connected with the top of the refueling filter screen assembly 1 and communicate with each other, so that the air passage communicates the oil tank with the outside to maintain the pressure balance between the oil tank and the atmosphere. The filter element 3 is used to be detachably and sealingly connected with the air filter head assembly 2 to filter the air passing through the air passage. The first sealing gasket 4 is arranged between the refueling filter screen assembly 1 and the air filter head assembly 2, and rotating the air filter head assembly 2 can move the air filter head assembly 2 towards the refueling filter screen assembly 1 and press the first sealing gasket 4. The anti-loosening assembly 5 comprises a first rotation limiting piece and a second rotation limiting piece. The first rotation limiting piece is installed on the refueling filter screen assembly 1, and the second rotation limiting piece is installed on the air filter head assembly 2. The first rotation limiting piece is used to be rotationally limitedly connected with the second rotation limiting piece to limit the air filter head assembly 2 from rotating towards loosening relative to the refueling filter screen assembly 1. The main components of the hydraulic air filter are clarified, which lays a foundation for the subsequent description of the functions of each part of the filter and the mutual cooperation relationship, so that the reader can understand the basic architecture of the filter as a whole. The detachable connection mode facilitates the installation and replacement of the refueling filter screen assembly 1, reducing the maintenance cost. The design of extending into the oil tank can directly filter the hydraulic oil when it is injected into the oil tank, effectively removing impurities, improving the cleanliness of the hydraulic oil entering the oil tank, and thus protecting the normal operation of the hydraulic system and prolonging the service life of the equipment. The use of non-metallic material can solve the rust problem of traditional metal air filter head and improve the anti-rust performance. The air passage provides a way for air exchange between the inside and outside of the oil tank, maintains the pressure balance between the inside and outside of the oil tank, protects the safety of the oil tank, and avoids affecting the normal operation of the equipment due to pressure imbalance. The detachable sealing connection facilitates the replacement of the filter element 3, improves the air filtering effect, removes dust, impurities and other substances in the air, prevents these substances from entering the oil tank and polluting the hydraulic oil, and improves the working environment of the hydraulic system. The first sealing gasket 4 can seal to prevent air, dust and other substances from entering the oil tank. By rotating the air filter head assembly 2 to press the sealing gasket, a good sealing effect can be achieved, the sealing performance is improved, and the risk of leakage is reduced. The setting of the anti-loosening assembly 5 effectively avoids loosening of the air filter head assembly 2 during equipment vibration or long-term use, ensures the stability and reliability of the overall structure, ensures the normal work of the filter, and reduces the leakage and other problems caused by loosening.

[0032] In a preferred embodiment, the first rotation limiting member comprises a plurality of tracks 51, and the second rotation limiting member comprises a plurality of protruding claws 52, which are used to be slidingly clamped in the tracks 51. The rotation of the air filter head assembly 2 can make the protruding claws 52 slide along the tracks 51 and move the air filter head assembly 2 to the oil filter screen assembly 1 to press the first sealing gasket 4. The tracks 51 can limit the sliding direction of the protruding claws 52 after the protruding claws 52 slide to the position where the oil filter screen assembly 1 is tightly connected with the air filter head assembly 2. The cooperation of the tracks 51 and the protruding claws 52 not only realizes the quick tightening action of the air filter head assembly 2, which is convenient to operate, but also accurately limits the position of the air filter head assembly 2 to prevent loosening, thereby improving the connection stability and sealing performance.

[0033] In a preferred embodiment, the track 51 comprises a starting end 511, a guide slope section 512, a retreat-stop section 513, a positioning section 514 and a limiting end 515 arranged in sequence. The limiting end 515 is used to limit the protruding claw 52 from sliding out of the track 51 from one end of the positioning section 514 away from the retreat-stop section 513. The guide slope section 512 is arranged in the direction from the air filter head assembly 2 to the oil filter screen assembly 1. The positioning section 514 is arranged in parallel with the first sealing gasket 4. The height of the connection position between the retreat-stop section 513 and the positioning section 514 is higher than the height of the connection position between the retreat-stop section 513 and the guide slope section 512, so as to limit the sliding block from sliding into the guide slope section 512 from the positioning end. The detailed segmented design of the track 51 makes the sliding process of the protruding claw 52 in the track 51 more smooth and the positioning more accurate. The guide slope section 512 guides the protruding claw 52 to move to the oil filter screen assembly 1 smoothly. The special height of the retreat-stop section 513 can effectively prevent loosening. The positioning section 514 ensures the air filter head assembly 2 to reach the accurate position. The limiting end 515 prevents the protruding claw 52 from sliding out of the track 51, thereby further enhancing the stability.

[0034] In a preferred embodiment, the protruding claw 52 is provided with an inclined guide surface 521 on the side facing the tightening direction of the air filter head assembly 2. The inclined guide surface 521 can play a guiding role in the process of tightening the air filter head assembly 2, so that the protruding claw 52 can slide along the track 51 more smoothly, thereby reducing the rotation resistance and improving the smoothness and convenience of the operation.

[0035] In a preferred embodiment, the first sealing gasket 4 is provided with a semicircular protruding structure 41 on the side facing the air filter head assembly 2. The semicircular protruding structure 41 increases the pressing effect of the air filter head assembly 2 on the first sealing gasket 4, thereby further improving the sealing performance and making the isolation of the oil tank from the outside better, effectively preventing the pollutants from entering. In addition, the pressed first sealing gasket 4 can form a pre-tightening force to prevent the protruding claw from crossing the retreat-stop section, thereby further improving the loosening prevention effect.

[0036] In a preferred embodiment, the oil filter assembly 1 comprises a flange 11, a second gasket 12, a filter screen 13, a support skeleton 14 and a bottom cover 15, the second gasket 12 is arranged between the flange 11 and the oil tank, the flange 11 is provided with a plurality of mounting holes 111 in the circumferential direction, the mounting holes 111 are used for the mounting screws 6 to fix the flange 11 to the oil tank, the flange 11 is arranged on the side away from the air filter head assembly 2 in the first annular groove 16, the bottom cover 15 is provided with a second annular groove 17, one end of the filter screen 13 is fixedly connected to the first annular groove 16 by glue, the other end is fixedly connected to the second annular groove 17 by glue, the support skeleton 14 is sleeved on the outside of the filter screen 13, and the two ends of the support skeleton 14 are fixedly connected to the first annular groove 16 and the second annular groove 17 by glue respectively, each track 51 is arranged on the outside of the end of the flange 11 close to the air filter head assembly 2, and the second gasket 12 enhances the sealing performance of the connection between the flange 11 and the oil tank; the mounting holes 111 facilitate the fixation to the oil tank; the annular grooves are used for fixing the filter screen 13 and the support skeleton 14, and ensure the structural stability of the filter screen 13; the tracks 51 arranged at specific positions provide accurate limiting positions for the anti-loosening assembly 5, and ensure the function and connection reliability of the entire oil filter assembly 1.

[0037] In a preferred embodiment, the number of tracks 51 is two, the two tracks 51 are uniformly arranged in the circumferential direction of the flange 11, the number of protruding claws 52 is two, and the two protruding claws 52 are uniformly arranged in the circumferential direction of the chuck 22. The uniform arrangement of the two tracks 51 and the two protruding claws 52 makes the connection between the air filter head assembly 2 and the oil filter assembly 1 more uniform in the circumferential direction, prevents local deformation or loosening caused by uneven stress, and further improves the structural stability.

[0038] In a preferred embodiment, the flange 11 is made of PPS material and is made by injection molding process, the bottom cover 15, the support skeleton 14 and the filter screen 13 are all made of stainless steel material, the PPS material has certain strength and corrosion resistance and will not rust, the injection molding process can ensure the dimensional accuracy and forming quality of the parts, improve the overall quality and durability of the product; the stainless steel material of the bottom cover 15, the support skeleton 14 and the filter screen 13 ensures their strength and corrosion resistance, prolonging the service life.

[0039] In a preferred embodiment, the air filter assembly 2 comprises a cap 21 and a flower disc 22, the cap 21 has a hollow cavity in the inside and has reinforcing ribs 211, the flower disc 22 is provided with a clamping plate 221 on one side close to the cap 21, the clamping plate 221 is used for clamping connection with the cap 21, a plurality of air inlet and outlet ports 226 are arranged on the circumference of the clamping plate 221, the cap 21 is thin-walled and has a cover shape structure to form a first inner cavity with the flower disc 22, the inner side of the flower disc 22 has a second inner cavity, the air inlet and outlet ports 226 are communicated with the first inner cavity, the first inner cavity is communicated with the second inner cavity, the second inner cavity is communicated with the inner side of the filter screen 13, the air inlet and outlet ports 226, the first inner cavity and the second inner cavity form an air passage, the internal structure of the air filter assembly 2 is clear, the reinforcing ribs 211 enhance the strength of the cap 21; the clamping connection mode is convenient for assembly; the formation of the air passage can make the air flow smoothly in each space, guarantee the air exchange function and improve the air filtration efficiency.

[0040] In a preferred embodiment, the number of air inlet and outlet ports 226 is eight, the eight air inlet and outlet ports 226 are uniformly arranged in the axial direction of the clamping plate 221, the uniformly arranged eight air inlet and outlet ports 226 make the air entering and flowing out more uniform and stable, avoid local airflow being too large or too small, and ensure the uniform distribution of air in the air passage and good air exchange effect.

[0041] In a preferred embodiment, a plurality of trapezoidal grooves 212, a plurality of limiting grooves 213 and a plurality of buckling handles 214 are arranged on the circumference of the side of the cap 21 close to the flower disc 22, a plurality of trapezoidal bosses 224, a plurality of limiting bosses 222 and a plurality of empty stops 223 are arranged on the outer side of the circumferential edge of the clamping plate 221, the trapezoidal bosses 224 are used for clamping in the trapezoidal grooves 212 to fix the clamping plate 221 in the axial direction, the limiting bosses 222 are used for clamping in the limiting grooves 213 to fix the limiting plate in the circumferential direction, the empty stops 223 are correspondingly arranged with the buckling handles 214, the cooperation of the trapezoidal grooves 212 and the bosses, the limiting grooves 213 and the limiting bosses 222, and the empty stops 223 and the buckling handles 214 not only realizes the firm axial and circumferential fixation of the clamping plate 221 and the cap 21, but also the correspondingly arranged buckling handles 214 facilitate disassembly and assembly, improve the installation convenience and ensure the structural stability.

[0042] In a preferred embodiment, the cap 21 is made of nylon material and is made by injection molding process, the flower disc 22 is made of PPS material and is made by injection molding process, the cap 21 made of nylon material has certain flexibility and strength and can avoid rust, the injection molding process ensures the molding quality and precision; the flower disc 22 made of PPS material has good rigidity and strength, the combination of the two materials meets the different performance requirements of the parts, and the injection molding process improves the production efficiency and product quality.

[0043] In a preferred embodiment, the filter element 3 comprises an O-shaped sealing ring 31, a clamping ring 33 and an empty filter sheet 32, the chuck 22 is provided with an annular baffle 227 extending towards the second inner cavity at one end close to the cover 21, the second inner cavity is provided with a clamping groove 225 close to the annular baffle 227, the top of the O-shaped sealing ring 31 abuts against the annular baffle 227, the empty filter sheet 32 is arranged on the side away from the O-shaped sealing ring 31, the clamping ring 33 is clamped in the clamping groove 225 and can extrude the empty filter sheet 32 to extrude and seal the empty filter sheet 32 and the O-shaped sealing ring 31, the O-shaped sealing ring and the clamping ring 33 cooperate to realize reliable fixation and sealing of the empty filter sheet 32, improve the sealing performance of air filtration, prevent unfiltered air from entering the oil tank, ensure the air filtration effect, and improve the overall performance of the hydraulic air filter.

[0044] The principle and implementation mode of the specific examples are described in the utility model, and the above embodiment is only used for helping to understand the method and core idea of the utility model; meanwhile, for the general skilled in the art, according to the idea of the utility model, there will be changes in the specific implementation mode and application range. In conclusion, the content of the specification should not be understood as the limitation of the utility model.

Claims

1. A hydraulic air filter of the self-tightening type, characterized in that: The utility model relates to a filter assembly for oil tank, comprising: a refueling filter screen assembly (1) which is detachably connected to the top opening of an equipment oil tank and part of the refueling filter screen assembly (1) extends into the oil tank at the top opening to filter hydraulic oil injected into the oil tank; an air filter head assembly (2) made of non-metallic material, provided with an air passage, used to be tightly connected with the top of the refueling filter screen assembly (1) and communicate with each other so that the air passage communicates the oil tank with the outside to maintain the balance between the pressure in the oil tank and the atmospheric pressure; a filter element (3) used to be detachably and sealingly connected with the air filter head assembly (2) to filter air passing through the air passage; a first sealing gasket (4) arranged between the refueling filter screen assembly (1) and the air filter head assembly (2), and the air filter head assembly (2) can be moved towards the refueling filter screen assembly (1) and press the first sealing gasket (4) by rotating the air filter head assembly (2); and an anti-loosening assembly (5) comprising a first rotation limiting member and a second rotation limiting member, the first rotation limiting member is installed on the refueling filter screen assembly (1), the second rotation limiting member is installed on the air filter head assembly (2), the first rotation limiting member is used to be rotationally and limitingly connected with the second rotation limiting member to limit the air filter head assembly (2) from rotating towards the loosening direction relative to the refueling filter screen assembly (1).

2. The hydraulic air filter according to claim 1, wherein: The first rotation limiting member comprises a plurality of tracks (51), the second rotation limiting member comprises a plurality of protruding claws (52), the protruding claws (52) are used to be slidingly clamped on the tracks (51), the protruding claws (52) can slide along the tracks (51) and move the air filter head assembly (2) towards the refueling filter screen assembly (1) to press the first sealing gasket (4) by rotating the air filter head assembly (2), and the tracks (51) can limit the protruding claws (52) from sliding towards the loosening direction after the protruding claws (52) slide to the position where the refueling filter screen assembly (1) and the air filter head assembly (2) are tightly connected.

3. The lock type hydraulic air filter according to claim 2, wherein: The track (51) comprises a starting end (511), a guide slope section (512), a retreat-stop section (513), a positioning section (514) and a limiting end (515) arranged in sequence, the limiting end (515) is used for limiting the protruding claw (52) from the positioning section (514) to slide out of the track (51) from one end of the retreat-stop section (513), the guide slope section (512) is arranged in a direction from the air filter head assembly (2) to the oil filling filter screen assembly (1) from the starting end (511) to the retreat-stop section (513), the positioning section (514) is arranged in parallel with the first sealing gasket (4), and the height of the connection position of the retreat-stop section (513) and the positioning section (514) is higher than the height of the connection position of the retreat-stop section (513) and the guide slope section (512) to limit the protruding claw (52) from the positioning section (514) to slide into the guide slope section (512).

4. The lock type hydraulic air filter according to claim 3, wherein: The protruding claw (52) is provided with an inclined guide surface (521) on one side in the tightening direction of the air filter head assembly (2).

5. The lock type hydraulic air filter according to claim 4, wherein: The oil filling filter screen assembly (1) comprises a flange (11), a second sealing gasket (12), a filter screen (13), a support framework (14) and a bottom cover (15), the second sealing gasket (12) is arranged between the flange (11) and the oil tank, a plurality of mounting holes (111) are arranged in the circumference of the flange (11), the mounting holes (111) are used for passing the mounting screws (6) to fixedly connect the flange (11) and the oil tank, the flange (11) is provided with a first annular groove (16) on the side away from the air filter head assembly (2), the bottom cover (15) is provided with a second annular groove (17), one end of the filter screen (13) is fixedly connected to the first annular groove (16), and the other end is fixedly connected to the second annular groove (17), the support framework (14) is sleeved on the outer side of the filter screen (13), and both ends of the support framework (14) are fixedly connected to the first annular groove (16) and the second annular groove (17) respectively, and each track (51) is arranged on the outer side of the flange (11) close to the air filter head assembly (2).

6. The lock type hydraulic air filter according to claim 5, wherein: The flange (11) is made of PPS material by injection molding process, and the bottom cover (15), the support framework (14) and the filter screen (13) are all made of stainless steel.

7. The lock type hydraulic air filter according to claim 6, wherein: The air filter head assembly (2) comprises a cap (21) and a chuck plate (22), the cap (21) has a hollow cavity in the inside and has reinforcing ribs (211), the chuck plate (22) is provided with a clamping plate (221) near one side of the cap (21), the clamping plate (221) is used for clamping connection with the cap (21), a plurality of air inlet and outlet ports (226) are arranged on the circumference of the clamping plate (221), the cap (21) is a thin-walled cover structure to form a first inner cavity with the chuck plate (22), the inner side of the chuck plate (22) has a second inner cavity, the air inlet and outlet ports (226) are communicated with the first inner cavity, the first inner cavity is communicated with the second inner cavity, and the second inner cavity is communicated with the inner side of the filter screen (13), the air inlet and outlet ports (226), the first inner cavity and the second inner cavity form the air channel.

8. The lock type hydraulic air filter according to claim 7, wherein: A plurality of trapezoidal grooves (212), a plurality of limiting grooves (213) and a plurality of buckle handles (214) are arranged on the circumference of the side of the cap (21) near the chuck plate (22), a plurality of trapezoidal bosses (224), a plurality of limiting bosses (222) and a plurality of empty stops (223) are arranged on the outer side of the circumferential edge of the clamping plate (221), the trapezoidal bosses (224) are used for clamping in the trapezoidal grooves (212) to fix the clamping plate (221) in the axial direction, the limiting bosses (222) are used for clamping in the limiting grooves (213) to fix the cap (21) in the circumferential direction, and the empty stops (223) are correspondingly arranged with the buckle handles (214).

9. The lock type hydraulic air filter according to claim 8, characterized by: The cap (21) is made of nylon material and is made by injection molding process, and the chuck plate (22) is made of PPS material and is made by injection molding process.

10. The lock type hydraulic air filter according to claim 9, characterized by: The filter element (3) comprises an O-shaped sealing ring (31), a clamping ring (33) and an air filter element (32), the chuck plate (22) is provided with an annular baffle (227) extending to the second inner cavity near one end of the cap (21), the second inner cavity is provided with a clamping groove (225) near the annular baffle (227), the top of the O-shaped sealing ring (31) abuts against the annular baffle (227), the air filter element (32) is arranged on the side of the O-shaped sealing ring (31) away from the cap (21), and the clamping ring (33) is clamped in the clamping groove (225) and can extrude the air filter element (32) to extrude and seal the air filter element (32) and the O-shaped sealing ring (31).

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