Return oil filter and construction machinery

Abstract

The present invention provides an oil return filter and construction machinery. The oil return filter includes: an oil return chamber having a filter element; a flange cover assembly including a flange cover, a flange fixed to the flange cover, and a bypass valve, the flange cover assembly covering the oil return chamber; a differential pressure detection mechanism for detecting the pressure difference before and after the filter element filters, installed on the flange cover, the differential pressure detection mechanism including a first pressure detection port and a second pressure detection port, the first pressure detection port communicating with the oil return chamber, and the second pressure detection port communicating with the inner cavity of the filter element. In the above structure, by providing a differential pressure detection mechanism on the flange cover, the change in the pressure difference before and after the filter element filters can be monitored without changing the structures of components such as the flange, which can simplify the overall structure of the oil return filter, reduce costs, and solve the defect that the structure of the oil return filter with a differential pressure detection mechanism in the prior art is relatively complex.

Description

Technical Field

[0001] The present invention relates to the technical field of construction machinery, and particularly relates to an oil return filter and a construction machinery. Background Art

[0002] In construction machinery such as excavators, an oil return filter is provided. When the hydraulic oil in the hydraulic circuit passes through the oil return filter, it will be filtered by the filter element in the oil return filter, and then flow back into the hydraulic oil tank after removing impurities. During actual use, as the working time goes by, more and more impurities will block the filter holes of the filter element, resulting in an increase in the pressure difference before and after the filter element and a decrease in the filtering efficiency of the filter element. When the pressure difference reaches a certain value, the filter element needs to be replaced.

[0003] Currently, in order to better monitor the change of the pressure difference before and after the filter element, a few oil return filters have set up a pressure difference detection mechanism. However, affected by the structural design, the above-mentioned oil return filters have many problems. Among them, the more prominent problem is that the pressure difference detection mechanism is often set on the flange, resulting in the complication of the structure of the flange and other components connected to the flange, and the overall structure of the oil return filter is relatively complex. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the structure of the oil return filter with a pressure difference detection mechanism in the prior art is relatively complex, so as to provide an oil return filter and a construction machinery.

[0005] To solve the above problems, the present invention provides an oil return filter, which includes: an oil return chamber having a filter element; a flange cover assembly including a flange cover, a flange fixed on the flange cover and a bypass valve, and the flange cover assembly covers the oil return chamber; a pressure difference detection mechanism for detecting the pressure difference before and after the filtration of the filter element, which is installed on the flange cover, and the pressure difference detection mechanism includes a first pressure detection port and a second pressure detection port, the first pressure detection port is communicated with the oil return chamber, and the second pressure detection port is communicated with the inner cavity of the filter element.

[0006] Optionally, a first channel and a second channel are provided on the flange cover, and a third channel is provided on the bypass valve; wherein, the first pressure detection port, the first channel and the oil return chamber are communicated in sequence, and the second pressure detection port, the second channel, the third channel and the inner cavity of the filter element are communicated in sequence.

[0007] Optionally, the flange cover includes a flange installation part and a cover plate part, the flange is fixed on the flange installation part, and the pressure difference detection mechanism, the first channel and the second channel are all arranged on the cover plate part.

[0008] Optionally, a first positioning part is provided on the flange cover, and a second positioning part is provided on the bypass valve; one of the first positioning part and the second positioning part is set as a convex part, and the other is set as a concave part, and the convex part is hermetically inserted into the concave part.

[0009] Optionally, a sealing ring is provided between the convex portion and the concave portion.

[0010] Optionally, the bypass valve includes a valve body disposed between the flange cover and the filter element. The third channel and the second positioning portion are both provided on the valve body. A connection channel is provided in the convex portion, and the connection channel communicates with the inner cavity of the concave portion to form an intermediate channel. The second channel communicates with the third channel through the intermediate channel.

[0011] Optionally, the valve body is fixed to the flange cover by a first connecting member. The first connecting member includes a first clamping portion provided on the flange cover and a second clamping portion provided on the valve body, and the first clamping portion is clamped with the second clamping portion.

[0012] Optionally, the bypass valve includes a valve body disposed between the flange cover and the filter element. The valve body is fixed to the flange cover by a second connecting member. The third channel is provided in the second connecting member.

[0013] Optionally, the second connecting member passes through the inner cavity of the concave portion and is connected to the convex portion.

[0014] The present invention also provides a construction machine, which includes the oil return filter as described above.

[0015] The present invention has the following advantages:

[0016] 1. By providing a pressure difference detection mechanism on the flange cover and connecting the first pressure detection port and the second pressure detection port of the pressure difference detection mechanism to the oil return cavity and the inner cavity of the filter element respectively, the pressure difference before and after the filter element is filtered can be detected by the pressure difference detection mechanism. From the perspective of the overall structural design, since the pressure difference detection mechanism is provided on the flange cover, there is no need to change the structure of the flange or other components, which can simplify the overall structure of the oil return filter and reduce costs.

[0017] 2. By providing a first channel and a second channel on the flange cover and a third channel on the bypass valve, the first pressure detection port can be communicated with the oil return cavity through the first channel, and the second pressure detection port can be communicated with the inner cavity of the filter element through the second channel, the third channel, forming a stable pressure difference monitoring path. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1Shows a schematic diagram of the overall sectional structure of the oil return filter provided in the first embodiment of the present invention;

[0020] Figure 2 Shows a schematic diagram of the partial sectional structure of the oil return filter provided in the first embodiment of the present invention;

[0021] Figure 3 Shows a schematic diagram of the overall oil flow of the oil return filter provided in the first embodiment of the present invention;

[0022] Figure 4 Shows a schematic diagram of the partial structure at the flange cover of the oil return filter provided in the first embodiment of the present invention;

[0023] Figure 5 Shows a three - dimensional structure diagram of the bypass valve in the oil return filter provided in the first embodiment of the present invention;

[0024] Figure 6 Shows an exploded structure diagram of the bypass valve in the oil return filter provided in the first embodiment of the present invention;

[0025] Figure 7 Shows a schematic diagram of the partial sectional structure of the oil return filter provided in the second embodiment of the present invention.

[0026] Explanation of reference numerals:

[0027] 10, filter element; 11, gasket; 20, oil return cavity; 30, flange cover assembly; 31, flange cover; 311, first hole; 312, second hole; 313, mounting sleeve; 314, flange mounting part; 315, cover plate part; 316, first positioning part; 3161, connecting hole; 317, first strengthening part; 318, fixing column; 32, flange; 33, bypass valve; 331, valve body; 3311, third hole; 3312, second positioning part; 3313, oil passage; 332, sealing ring; 333, valve bolt; 334, valve core; 335, valve spring; 336, spring retainer; 337, nut; 40, differential pressure detection mechanism; 41, first pressure detection port; 42, second pressure detection port; 50, first connecting piece; 51, first clamping part; 511, clamping block; 52, second clamping part; 521, clamping frame; 522, clamping groove; 523, boss; 53, fastener; 60, second connecting piece; 70, elastic piece. Detailed implementation manners

[0028] Next, the technical solutions of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Embodiment 1

[0033] This embodiment provides an oil return filter, as Figures 1 - 3 shown, which includes an oil return chamber 20 having a filter element 10, a flange cover assembly 30, and a differential pressure detection mechanism 40. Among them, the flange cover assembly 30 includes a flange cover 31, a flange 32 fixed on the flange cover 31, and a bypass valve 33. The flange cover assembly 30 covers the oil return chamber 20. The differential pressure detection mechanism 40 is used to detect the pressure difference before and after the filtration of the filter element 10. The differential pressure detection mechanism 40 is installed on the flange cover 31. The differential pressure detection mechanism 40 includes a first pressure detection port 41 and a second pressure detection port 42. The first pressure detection port 41 is communicated with the oil return chamber 20, and the second pressure detection port 42 is communicated with the inner cavity of the filter element 10.

[0034] According to the above settings, when the oil return filter operates, the oil will enter the oil return chamber 20, and then flow through the filter element 10 and be filtered by the filter element 10. During this process, by keeping the differential pressure detection mechanism 40 running, the oil pressure in the oil return chamber 20 can be detected through the first pressure detection port 41, and the oil pressure in the inner cavity of the filter element 10 can be detected through the second pressure detection port 42. By taking the difference between the oil pressure in the oil return chamber 20 and the oil pressure in the inner cavity of the filter element 10, the pressure difference before and after the filtration of the filter element 10 can be obtained, and the monitoring of the filtration efficiency of the filter element 10 can be realized.

[0035] From the perspective of the overall structural design, since the pressure difference detection mechanism 40 is provided on the flange cover 31, there is no need to change the structure of the flange 32 or other components, which can simplify the overall structure of the oil return filter and reduce costs.

[0036] In this embodiment, the oil return filter further includes a housing, which is sleeved outside the filter element 10 at intervals to cooperate with the filter element 10 to form an oil return cavity 20.

[0037] For the flange cover 31, refer to Figure 2 , on which a first channel 311 and a second channel 312 are provided. Correspondingly, a third channel 3311 is provided on the bypass valve 33. Among them, the first pressure detection port 41, the first channel 311, and the oil return cavity 20 are communicated in sequence, and the second pressure detection port 42, the second channel 312, the third channel 3311, and the inner cavity of the filter element 10 are communicated in sequence. According to this, a stable pressure difference monitoring path can be formed for the pressure difference detection mechanism 40 to detect the pressure difference before and after the filtration of the filter element 10, and the change of the pressure difference before and after the filtration of the filter element 10 can be stably monitored.

[0038] Preferably, the pressure difference detection mechanism 40 is set as a pressure difference sensor, and the pressure difference sensor is integrated with a first pressure detection port 41 and a second pressure detection port 42. In this embodiment, as Figure 2 shown, an installation sleeve 313 is provided on the side of the flange cover 31 facing away from the filter element 10, and the pressure difference sensor is installed in the installation sleeve 313 for easy installation and replacement. It should be noted that after the pressure difference sensor is installed in the installation sleeve 313, the pressure difference sensor realizes the separation of the first pressure detection port 41 and the second pressure detection port 42 by itself.

[0039] Furthermore, two openings are provided on the inner wall of the installation sleeve 313. One of the openings corresponds to the first pressure detection port 41 and extends towards the oil return cavity 20 to form a first channel 311 directly communicated with the oil return cavity 20; the other opening corresponds to the second pressure detection port 42 and extends towards the inner cavity of the filter element 10 to form a second channel 312 communicated with the inner cavity of the filter element 10.

[0040] In terms of a more specific structure, refer to Figure 3 , the flange cover 31 includes a flange installation part 314 and a cover plate part 315. The flange 32 is fixed on the flange installation part 314, and the pressure difference detection mechanism 40, the first channel 311, and the second channel 312 are all provided on the cover plate part 315. At this time, the pressure difference detection mechanism 40, the first channel 311, and the second channel 312 are all located at a part of the flange cover 31 that does not face the flange 32 directly. Only the flange cover 31 needs to be designed without changing the structure of the flange 32, which can effectively ensure the simplicity of the overall structure of the oil return filter.

[0041] Next, other settings in this oil return filter will be further introduced.

[0042] As Figure 2 shown, a first positioning portion 316 is provided on the flange cover 31, and a second positioning portion 3312 is provided on the bypass valve 33. Among them, the first positioning portion 316 is set as a convex portion, and the second positioning portion 3312 is set as a concave portion, and the convex portion is hermetically inserted into the concave portion. In this way, when the flange cover 31 and the bypass valve 33 are connected, the accuracy of the alignment of the second channel 312 and the third channel 3311 can be ensured, and the stability of pressure monitoring can be ensured.

[0043] Preferably, a sealing ring 332 is provided between the convex portion and the concave portion to achieve sealing between the convex portion and the concave portion. In this embodiment, the convex portion is set as a columnar structure, and the concave portion is set as a sleeve structure, and an annular groove is provided along the circumferential direction inside the sleeve structure to realize the installation of the sealing ring 332.

[0044] In other embodiments, the first positioning portion 316 can also be set as a concave portion, and the second positioning portion 3312 can be set as a convex portion.

[0045] Furthermore, the bypass valve 33 includes a valve body 331. The valve body 331 is provided between the flange cover 31 and the filter element 10. Both the third channel 3311 and the second positioning portion 3312 are provided on the valve body 331. A connection channel 3161 is provided inside the first positioning portion 316, and the connection channel 3161 communicates with the inner cavity of the second positioning portion 3312 to form an intermediate channel, and the second channel 312 communicates with the third channel 3311 through the intermediate channel.

[0046] In this way, when the flange 32 and the flange cover 31 are connected, inserting the first positioning portion 316 into the second positioning portion 3312 can construct the intermediate channel, thereby ensuring the stable connection between the second channel 312 and the third channel 3311. In addition, since the space between the first positioning portion 316 and the second positioning portion 3312 is relatively sealed, it can be avoided that the intermediate channel communicates with the space outside the first positioning portion 316 or the second positioning portion 3312, ensuring that the differential pressure detection mechanism 40 can accurately detect the pressure in the inner cavity of the filter element 10 through the second pressure detection port 42.

[0047] In this embodiment, the first positioning portion 316 is provided on the side of the flange cover 31 facing the valve body 331 (i.e., Figure 2 the lower side of the flange cover 31 in Figure 2 ), and the second positioning portion 3312 is provided on the side of the valve body 331 facing the flange cover 31 (i.e.,

[0048] the upper side of the valve body 331 in Figure 2, on one side of the flange cover 31 facing the bypass valve 33, a first reinforcing portion 317 is further provided. At least part of the first reinforcing portion 317 extends towards the bypass valve 33 to form a first positioning portion 316, so as to improve the overall structural strength of the flange cover 31. In this embodiment, the first reinforcing portion 317 has a boss structure, and the first passage 311 is also provided in the first reinforcing portion 317.

[0049] In other embodiments, referring to the setting of the first reinforcing portion 317, a second reinforcing portion may also be provided on one side of the bypass valve 33 facing the flange cover 31, so that at least part of the second reinforcing portion extends towards the flange cover 31 to form a second positioning portion 3312, so as to improve the overall structural strength of the bypass valve 33.

[0050] As Figure 2 shown, the valve body 331 is fixed to the flange cover 31 through a first connecting member 50. The first connecting member 50 includes a first clamping portion 51 provided on the flange cover 31 and a second clamping portion 52 provided on the valve body 331. The first clamping portion 51 and the second clamping portion 52 are clamped together. In this way, when replacing the filter element 10, the flange cover 31 and the bypass valve 33 can be disassembled and assembled as a whole, which is more convenient for replacing the filter element 10. Of course, the flange cover 31 and the bypass valve 33 are still detachable, and the flange cover 31 and the bypass valve 33 can be designed separately to meet the pressure difference monitoring requirements.

[0051] In this embodiment, in combination with Figure 2 、 Figure 4 and Figure 5 , a clamping block 511 is provided on the first clamping portion 51, and a clamping groove 522 is provided on the second clamping portion 52. At this time, the bypass valve 33 can rotate along its own axis, so that the clamping block 511 and the clamping groove 522 are clamped, realizing the fixation between the flange cover 31 and the bypass valve 33; the bypass valve 33 can also rotate along its own axis, so that the clamping block 511 and the clamping groove 522 are disengaged, realizing the disassembly between the flange cover 31 and the bypass valve 33.

[0052] Furthermore, the first connecting member 50 further includes a fastening member 53. Referring to Figure 2 and Figure 4 , a fixing column 318 is provided on one side of the flange cover 31 facing the valve body 331. The first clamping portion 51 is detachably and fixedly connected to the fixing column 318 through the fastening member 53. During installation, the first clamping portion 51 can be first disengaged from the fixing column 318, the first clamping portion 51 and the second clamping portion 52 are clamped together, then the first positioning portion 316 and the second positioning portion 3312 are aligned, and the first clamping portion 51 is fixed to the fixing column 318, which is more convenient for installation.

[0053] In terms of a more specific structure, referring to Figure 4 , the first clamping portion 51 is set as a columnar structure, and a clamping block 511 protrudes from one side in the radial direction. Referring toFigure 5 The second clamping portion 52 is arranged as a frame structure, which includes a clamping frame 521 and a boss 523. The clamping frame 521 and the valve body 331 cooperate to form a folded-angle clamping groove 522. The clamping block 511 enters from the left side of the clamping groove 522 and is clamped on the right side of the clamping groove 522. To prevent the clamping block 511 from disengaging from the clamping groove 522, a boss 523 is also arranged in the second clamping portion 52.

[0054] Of course, in other embodiments, the structural shapes of the first clamping portion 51 and the second clamping portion 52 can also be interchanged, so that the clamping groove 522 is arranged on the first clamping portion 51 and the clamping block 511 is arranged on the second clamping portion 52.

[0055] Next, the specific structure of the bypass valve 33 will be further introduced.

[0056] As Figure 2 shown, the valve body 331 is hermetically crimped to the end of the filter element 10. Specifically, a sealing gasket 11 is arranged between the lower side of the valve body 331 and the upper end of the filter element 10 to achieve a sealed connection between the bypass valve 33 and the filter element 10.

[0057] Combined with Figure 5 and Figure 6 , in addition to the valve body 331 and the sealing ring 332 installed on the valve body 331, the bypass valve 33 further includes a valve bolt 333, a valve core 334, a valve spring 335, a spring retaining ring 336 and a nut 337. Among them, the valve bolt 333 is arranged through the valve body 331 from top to bottom. Below the valve body 331, the valve core 334, the valve spring 335, the spring retaining ring 336 and the nut 337 are sleeved on the valve bolt 333 in sequence from top to bottom. Among them, the valve core 334 is also arranged opposite to the oil passage 3313 on the valve body 331.

[0058] The main working process of the bypass valve 33 is as follows: when the filter element 10 is in a non-blocked state, under the action of the valve spring 335, the valve core 334 abuts against the valve body 331, the oil passage 3313 is closed, and the oil entering the return oil filter flows out after being filtered by the filter element 10; when the filter element 10 is in a blocked state, the valve core 334 moves downward against the elastic force of the valve spring 335, the oil passage 3313 is opened, and the oil entering the return oil filter directly flows out through the inner cavity of the bypass valve 33 and the filter element 10.

[0059] In other aspects, as Figure 2 shown, an elastic member 70 is also arranged between the flange cover 31 and the valve body 331. In this embodiment, the elastic member 70 is arranged as a spring, and it is installed in the spaced space formed by the cooperation of the first positioning portion 316, the second positioning portion 3312, the first clamping portion 51 and the second clamping portion 52, and the overall structure is very compact.

[0060] This embodiment also provides a construction machinery, which includes the oil return filter as described above. Exemplarily, the construction machinery can be an excavator, a crane, a concrete pump truck, etc.

[0061] Taking an excavator as an example, the above-mentioned oil return filter can be installed inside the hydraulic oil tank of the excavator to serve as a part of the hydraulic oil tank, or can be installed outside the hydraulic oil tank to be independent of the hydraulic oil tank.

[0062] According to the above description, the present application mainly has the following advantages:

[0063] 1. By arranging the differential pressure detection mechanism 40 on the flange cover 31, without changing the structures of components such as the flange 32, the simplicity of the overall structure of the oil return filter can be ensured;

[0064] 2. By arranging the first pressure detection port 41, the first passage 311 to communicate with the oil return chamber 20, and arranging the second pressure detection port 42, the second passage 312, the third passage 3311 to communicate with the inner cavity of the filter element 10, a differential pressure monitoring path can be formed to stably and reliably monitor the change of the pressure difference before and after the filter element 10;

[0065] 3. Through the cooperation between the first positioning portion 316 and the second positioning portion 3312, the accuracy of the alignment between the flange cover 31 and the bypass valve 33 can be ensured, and further the stability of the pressure monitoring can be ensured;

[0066] 4. Through the cooperation between the first clamping portion 51 and the second clamping portion 52, the flange cover 31 and the bypass valve 33 can be disassembled and assembled relative to the filter element 10 as a whole, which is more convenient for replacing the filter element 10, and subsequent disassembly between the flange cover 31 and the bypass valve 33 is not hindered.

[0067] Embodiment Two

[0068] This embodiment provides an oil return filter, which is basically the same as the oil return filter provided in Embodiment One, and the main difference lies in: the connection setting between the valve body 331 and the flange cover 31 is different.

[0069] In this embodiment, as Figure 7 shown, the bypass valve 33 includes a valve body 331, the valve body 331 is arranged between the flange cover 31 and the filter element 10, and the valve body 331 is fixed to the flange cover 31 through a second connecting member 60. At this time, the second positioning portion 3312 is arranged on the valve body 331, and the third passage 3311 is arranged in the second connecting member 60. In this way, while the flange cover 31 and the valve body 331 are connected through the second connecting member 60, the third passage 3311 can be constructed, and the structure is simple and ingenious.

[0070] Furthermore, the second connecting member 60 passes through the inner cavity of the concave portion and is connected to the convex portion, and the overall structure is compact, which can effectively save the installation space.

[0071] Preferably, the second connecting member 60 is provided as an oil-passing bolt, which has a simple structure and low cost. Since the structure of the oil-passing bolt is a prior art, it will not be described in detail here.

[0072] In this embodiment, along the circumferential direction of the flange cover 31, a plurality of first positioning portions 316 are provided; a plurality of second positioning portions 3312 and second connecting members 60 are also correspondingly provided to ensure the stability of the connection between the flange cover 31 and the valve body 331.

[0073] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An oil return filter, characterized in that, Comprising: An oil return chamber (20) having a filter element (10); A flange cover assembly (30), including a flange cover (31), a flange (32) fixed to the flange cover (31), and a bypass valve (33), the flange cover assembly (30) covering the oil return chamber (20); A differential pressure detection mechanism (40) for detecting the pressure difference before and after the filter element (10) filters, installed on the flange cover (31), the differential pressure detection mechanism (40) including a first pressure detection port (41) and a second pressure detection port (42), the first pressure detection port (41) communicating with the oil return chamber (20), and the second pressure detection port (42) communicating with the inner cavity of the filter element (10); A first passage (311) and a second passage (312) are provided on the flange cover (31), a third passage (3311) is provided on the bypass valve (33), the first pressure detection port (41), the first passage (311), and the oil return chamber (20) are sequentially communicated, and the second pressure detection port (42), the second passage (312), the third passage (3311), and the inner cavity of the filter element (10) are sequentially communicated; The flange cover (31) includes a flange mounting portion (314) and a cover plate portion (315), the flange (32) is fixed to the flange mounting portion (314), the differential pressure detection mechanism (40), the first passage (311), and the second passage (312) are all provided on the cover plate portion (315); a first positioning portion (316) is provided on the flange cover (31), and a second positioning portion (3312) is provided on the bypass valve (33); One of the first positioning portion (316) and the second positioning portion (3312) is provided as a convex portion, and the other is provided as a concave portion, and the convex portion is hermetically inserted into the concave portion; The bypass valve (33) includes a valve body (331), the valve body (331) is disposed between the flange cover (31) and the filter element (10), and the third passage (3311) and the second positioning portion (3312) are both provided on the valve body (331); A connection passage (3161) is provided in the convex portion, and the connection passage (3161) communicates with the inner cavity of the concave portion to form an intermediate passage, and the second passage (312) communicates with the third passage (3311) through the intermediate passage; 2. The oil return filter according to claim 1, characterized in that, A sealing ring (332) is provided between the convex portion and the concave portion; 3. The oil return filter according to claim 1 or 2, characterized in that, The valve body (331) is fixed to the flange cover (31) by a first connecting member (50), the first connecting member (50) includes a first clamping portion (51) provided on the flange cover (31) and a second clamping portion (512) provided on the valve body (331), and the first clamping portion (51) is clamped with the second clamping portion (512).

4. The oil return filter according to claim 1 or 2, characterized in that, The bypass valve (33) includes a valve body (331). The valve body (331) is arranged between the flange cover (31) and the filter element (10), and the valve body (331) is fixed to the flange cover (31) through a second connecting member (60). The third channel (3311) is arranged in the second connecting member (60).

5. The oil return filter according to claim 4, characterized in that, The second connecting member (60) passes through the inner cavity of the concave portion and is connected to the convex portion.

6. An engineering machinery, characterized in that, It includes an oil return filter according to any one of claims 1-5.

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