An electro-hydraulic flow servo valve with external oil filter

Abstract

The present application discloses an electro-hydraulic flow servo valve with an external oil filter, which relates to the technical field of servo valves, and comprises: a pilot oil inlet housing; an oil filter assembly, which comprises a butterfly-shaped sheet oil filter and an oil filter cover, the oil filter cover matches the oil filter groove; the butterfly-shaped sheet oil filter is located in the oil filter groove and is arranged on the rear end surface of the oil filter cover; the pilot oil inlet housing and the oil filter cover are both provided with a plurality of oil passages; two oil inlet throttle plugs, each of which is provided with a throttle hole, and the oil passages of the pilot oil inlet housing, the oil filter cover and other structures form a complete pilot oil passage; the pilot oil passage guides the oil from the two P of the pilot oil inlet housing to the pilot oil inlet housing; S The oil entering the oil inlet is collected and filtered by a butterfly-shaped sheet oil filter before being divided into two symmetrical paths, each of which flows through a throttle hole to a nozzle and one end of the valve core. The electro-hydraulic flow servo valve of the present application solves the problem of cumbersome maintenance procedures of traditional electro-hydraulic flow servo valves by setting an external oil filter assembly and cooperating with corresponding pilot oil channels.

Description

Technical Field

[0001] The present application relates to the technical field of servo valves, and in particular to an electro-hydraulic flow servo valve with an external oil filter. Background Art

[0002] At present, the electro-hydraulic flow servo valve originated from the Western industry in the 1940s and has developed rapidly. Before this, hydraulic transmission systems and electric transmission systems have been widely used. From practice, people gradually realized that the motion inertia of the actuator of hydraulic transmission is much smaller than the motor inertia of electric transmission. Therefore, for systems with high power, large inertia and relatively high response requirements, the use of hydraulic transmission systems has obvious advantages, while the electric transmission system has the advantages of rapid signal transmission, convenient signal correction and processing, and easy to implement various feedback and control strategies and remote control. Therefore, the two types of transmission systems are combined to make an electro-hydraulic integrated servo control system, which has great application prospects. After a lot of theoretical research, scientific and technological workers have developed a patented product called electro-hydraulic servo valve, among which the most typical one is the double nozzle baffle force feedback electro-hydraulic flow servo valve.

[0003] After decades of development, the dual nozzle flapper force feedback electro-hydraulic flow servo valve has been widely used in industrial production and plays a vital role in specific fields. In my country, the cost of purchasing and maintaining electro-hydraulic flow servo valves is more than 100 billion yuan each year; even the cost of maintenance during use has reached tens of billions. Among them, the main maintenance work is to repair the performance failure of the electro-hydraulic flow servo valve caused by oil contamination.

[0004] In the related art, the cross-sectional diagram of the conventional electro-hydraulic flow servo valve is as follows: Figure 1 As shown, the filter device of the electro-hydraulic flow servo valve adopts a tubular oil filter 10, two throttling holes 11 are arranged at both ends of the tubular oil filter 10, an oil plug 15 is arranged outside each throttling hole 11, and a gland 17 is arranged outside the oil plug 15. The tubular oil filter 10 is built in the center of the entire device, specifically between the electromagnetic device 16 and the valve core 14.

[0005] When the oil is polluted, the tubular oil filter 10 built into the electro-hydraulic flow servo valve fails due to long-term operation and needs to be repaired; the inspection of the tubular oil filter 10 requires the electro-hydraulic flow servo valve to be disassembled, the two outermost glands 17 are first removed, and then the oil plugs 15 at both ends are removed with special tools, and finally the built-in tubular oil filter 10 is taken out, and then the tubular oil filter 10 can be inspected, cleaned and replaced. Each repair requires professional manufacturers and professional staff to use special tools for removal and installation, which is time-consuming, labor-intensive and expensive; more importantly, each removal involves the throttle hole 11. For electro-hydraulic flow servo valves with extremely high precision requirements, when the repair is completed and assembled, the valve core 14 needs to be re-zeroed with special equipment, and the process is extremely cumbersome. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of this application is to provide an electro-hydraulic flow servo valve with an external oil filter, which solves the problem of complicated maintenance procedures of traditional electro-hydraulic flow servo valves by setting an external oil filter assembly and cooperating with corresponding pilot oil channels.

[0007] In order to achieve the above purpose, the technical solution adopted is: an electro-hydraulic flow servo valve with an external oil filter, comprising:

[0008] The pilot oil inlet housing has an oil filter groove on its front end;

[0009] An external oil filter assembly comprises a butterfly-shaped sheet oil filter and an oil filter cover, wherein the oil filter cover matches the oil filter tank; the butterfly-shaped sheet oil filter is located in the oil filter tank and is arranged on the rear end surface of the oil filter cover; the pilot oil inlet housing and the oil filter cover are both provided with a plurality of oil passages;

[0010] Two oil inlet throttle plugs are symmetrically arranged on the rear end surface of the pilot oil inlet housing, each of which is provided with a throttle hole. The pilot oil inlet housing, the oil filter cover and other oil paths form a complete pilot oil passage.

[0011] The pilot oil passage guides the two P S The oil entering from the oil inlet is collected and filtered by a butterfly-shaped sheet oil filter before being divided into two symmetrical paths. Each path flows through a throttling hole to a nozzle and one end of the valve core.

[0012] Based on the above technical solution, the oil filter assembly also includes a double-layer sealing ring, which clamps the butterfly-shaped sheet oil filter to the rear end face of the oil filter cover; and the rear half of the double-layer sealing ring is used to separate and filter the rear end face of the oil filter groove to form a dirt receiving cavity.

[0013] On the basis of the above technical solution, the oil circuit of the pilot oil inlet housing includes a total oil inlet circuit before filtering, and the oil circuit of the oil filter cover includes two filter cover outlet oil circuits and two filter cover inlet oil circuits;

[0014] The oil in the main oil inlet before filtration is from two P S The oil inlet is gathered and enters the oil filter cover from the two filter cover oil inlet passages, and flows out from the two filter cover oil outlet passages to the two throttling holes respectively.

[0015] Based on the above technical solution, the front end faces of the pilot oil inlet housing and the oil filter cover are both circular, and the oil filter cover is located in the center of the pilot oil inlet housing; the front end face of the oil filter cover is flush with the front end face of the pilot oil inlet housing.

[0016] Based on the above technical solution, the oil filter groove is a stepped cylindrical hole, the oil filter cover is a stepped cylindrical shape, and its front half has a large diameter and the rear half has a small diameter; the double-layer sealing ring is sleeved on the rear half of the oil filter cover.

[0017] On the basis of the above technical solution, a forward-concave storage and diversion cavity is provided on the rear end surface of the rear half of the oil filter cover.

[0018] On the basis of the above technical solution, the butterfly-shaped sheet oil filter is formed by folding multiple layers of stainless steel wire mesh.

[0019] On the basis of the above technical solution, the electro-hydraulic flow servo valve further includes a valve sleeve located in the middle, and the oil inlet throttle plug is clamped between the pilot oil inlet housing and the main valve sleeve.

[0020] On the basis of the above technical solution, the electro-hydraulic flow servo valve also includes a pilot oil outlet housing and two left and right end covers, each end cover has two oil circuits respectively connected to the nozzle and the valve core end; the pilot oil outlet housing has an L-shaped oil circuit, and the L-shaped oil circuit is connected to one of the oil circuits of the end cover.

[0021] On the basis of the above technical solution, the electro-hydraulic flow servo valve further comprises a nozzle seat body, two nozzles are mounted on the nozzle seat body, and the nozzle seat body is provided with an oblique flow channel, and the oblique flow channel is connected to the L-shaped oil circuit.

[0022] The beneficial effects of the technical solution provided by this application include:

[0023] 1. The electro-hydraulic flow servo valve of the present application adopts an external oil filter assembly, and the butterfly-shaped sheet oil filter in the oil filter assembly replaces the traditional tubular oil filter. In comparison, when the traditional electro-hydraulic flow servo valve needs to replace or clean the tubular oil filter, it is necessary to repeatedly disassemble and assemble its main structure (pressure cover and oil plug), and it is also necessary to use special equipment to re-zero the valve core; when the electro-hydraulic flow servo valve of the present application replaces or cleans the butterfly sheet oil filter, it is only necessary to remove the oil filter cover and replace the butterfly sheet oil filter, avoiding the disassembly of the main structure of the electro-hydraulic flow servo valve during the oil filter replacement process, and there is no need to zero the valve core, simplifying the replacement or cleaning process; at the same time, the butterfly sheet oil filter has a stronger dirt holding capacity than the tubular oil filter. The electro-hydraulic flow servo valve of the present application improves the dirt holding capacity of the servo valve, extends the life of the servo valve, improves production efficiency, and increases profits.

[0024] 2. The electro-hydraulic flow servo valve of the present application is provided with an external oil filter assembly, a corresponding oil inlet throttle plug is added, and the pilot oil inlet housing, valve sleeve, pilot oil outlet housing, left and right end covers and nozzle seat body are uniquely modified to form a complete pilot oil passage, so that the pilot oil passage meets the requirements of first filtering and then diverting to flow through two throttle holes to the nozzle and valve core, thereby meeting the function of the original electro-hydraulic flow servo valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 is a cross-sectional schematic diagram of a conventional electro-hydraulic flow servo valve;

[0027] Figure 2 A cross-sectional schematic diagram of an electro-hydraulic flow servo valve provided in an embodiment of the present application;

[0028] Figure 3 for Figure 2 An exploded schematic diagram of the pilot oil inlet housing and oil filter assembly;

[0029] Figure 4 Another cross-sectional schematic diagram of the electro-hydraulic flow servo valve provided in an embodiment of the present application;

[0030] Figure 5 A schematic diagram of a pilot oil passage of an electro-hydraulic flow servo valve provided in an embodiment of the present application (arrows in the figure form the pilot oil passage);

[0031] Reference numerals:

[0032] 10. Tubular oil filter; 11. Throttle hole; 12. Nozzle; 13. Baffle; 14. Valve core; 15. Oil plug; 16. Electromagnetic device; 17. Gland;

[0033] 1. Double-layer sealing ring; 2. Butterfly-shaped oil filter; 3. Oil filter cover; 4. Oil outlet of filter cover; 5. Oil inlet of filter cover; 6. Main oil inlet before filter;

[0034] 20, pilot oil inlet housing; 201, oil filter tank; 202, P S Oil inlet; 21, oil inlet throttle plug; 22, valve sleeve; 23, end cover; 24, oil lead-out housing; 25, nozzle seat; 26, dirt receiving chamber; 28, storage and diversion chamber. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present application clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] like Figures 2 to 5 As shown, the present application discloses an embodiment of an electro-hydraulic flow servo valve with an external oil filter. The electro-hydraulic flow servo valve mainly includes an external oil filter assembly, and the other related structures are uniquely modified to adapt to the external oil filter assembly. The electro-hydraulic flow servo valve of the present application solves the problem of cumbersome maintenance work of the traditional electro-hydraulic flow servo valve by setting an external oil filter assembly and cooperating with the corresponding pilot oil channel.

[0037] The electro-hydraulic flow servo valve includes a pilot oil inlet housing 20, an oil filter assembly and two oil inlet throttle plugs 21. The front end face of the pilot oil inlet housing 20 is provided with an oil filter groove 201. The external oil filter assembly includes a butterfly-shaped sheet oil filter 2 and an oil filter cover 3, and the oil filter cover 3 is matched and installed in the oil filter groove 201. The butterfly-shaped sheet oil filter 2 is located in the oil filter groove 201 and is arranged on the rear end face of the oil filter cover 3, that is, the oil filter cover 3 and the pilot oil inlet housing 20 clamp the butterfly-shaped sheet oil filter 2 in the oil filter groove 201. The pilot oil inlet housing 20 and the oil filter cover 3 are both provided with a plurality of oil circuits.

[0038] Two oil inlet throttle plugs 21 are symmetrically arranged on the rear end face of the pilot oil inlet housing 20. Each oil inlet throttle plug 21 is provided with a throttle hole 11, and the oil passage of the pilot oil inlet housing 20, the oil filter cover 3 and other structures forms a complete pilot oil passage (see Figure 5 ).

[0039] The pilot oil passage guides the two P SThe oil entering the oil inlet 202 is collected and filtered by the butterfly-shaped sheet oil filter 2 before being divided into two symmetrical paths, each of which flows through a throttling hole 11 to a nozzle 12 and one end of the valve core 14 .

[0040] It is worth noting that this application only introduces S The oil inlet 202 to the nozzle 12 and one end of the valve core 14, and the remaining oil passages are well known to those skilled in the art and are therefore not described in detail.

[0041] The electro-hydraulic flow servo valve of the present application adopts an external oil filter assembly, and the butterfly-shaped sheet oil filter 2 in the oil filter assembly replaces the traditional tubular oil filter 10. In comparison, when the traditional electro-hydraulic flow servo valve needs to replace or clean the tubular oil filter 10, it is necessary to repeatedly disassemble and assemble its main structure (pressure cover 17 and oil plug 15), and it is also necessary to use special equipment to re-zero the valve core 14; when the electro-hydraulic flow servo valve of the present application replaces or cleans the butterfly sheet oil filter 2, it is only necessary to remove the oil filter cover 3 and replace the butterfly sheet oil filter 2, avoiding the disassembly of the main structure of the electro-hydraulic flow servo valve during the oil filter replacement process, and there is no need to zero the valve core 14. At the same time, the dirt holding capacity of the butterfly sheet oil filter 2 is stronger than that of the tubular oil filter 10. The electro-hydraulic flow servo valve of the present application improves the dirt holding capacity of the servo valve, extends the life of the servo valve, improves production efficiency, and increases revenue.

[0042] like Figure 2 and Figure 3 As shown, the oil filter assembly further includes a double-layer sealing ring 1, which clamps the butterfly-shaped sheet oil filter 2 to the rear end surface of the oil filter cover 3. The rear half of the double-layer sealing ring 1 is used to separate and filter the rear end surface of the oil tank 201 to form a dirt receiving chamber 26. The dirt receiving chamber 26 can further enhance the dirt receiving capacity of the butterfly-shaped sheet oil filter 2.

[0043] like Figure 3 As shown, further, the oil circuit of the pilot oil inlet housing 20 includes a pre-filter main oil inlet circuit 6 , and the oil circuit of the oil filter cover 3 includes two filter cover oil outlet circuits 4 and two filter cover oil inlet circuits 5 .

[0044] In actual work, the oil flows from two P S The oil enters from the oil inlet 202, is collected through the main oil inlet passage 6 before filtration, passes through the butterfly-shaped sheet oil filter 2, enters the oil filter cover 3 from the two filter cover oil inlet passages 5, and flows out from the two filter cover oil outlet passages 4 to the two throttling holes 11 respectively.

[0045] The electro-hydraulic flow servo valve of the present application is provided with a unique oil path in the pilot oil inlet housing 20 and the oil filter cover 3, so that the oil filter can be externally placed and still function normally as the original electro-hydraulic flow servo valve.

[0046] Preferably, the front end faces of the pilot oil inlet housing 20 and the oil filter cover 3 are both circular, and the oil filter cover 3 is located in the center of the pilot oil inlet housing 20 ; the front end face of the oil filter cover 3 is flush with the front end face of the pilot oil inlet housing 20 .

[0047] like Figure 3 As shown, specifically, the oil filter groove 201 is a stepped cylindrical hole, the oil filter cover 3 is a stepped cylindrical shape, and the front half of the oil filter cover 3 has a large diameter, and the rear half of the oil filter cover 3 has a small diameter; the double-layer sealing ring 1 is sleeved on the rear half of the oil filter cover 3.

[0048] Furthermore, the rear end surface of the rear half of the oil filter cover 3 is provided with a forward concave storage and diversion chamber 28. The front and rear sides of the butterfly-shaped sheet oil filter 2 are respectively the storage and diversion chamber 28 and the dirt receiving chamber 26, which free up more space on both sides of the butterfly-shaped sheet oil filter 2, thereby improving the efficiency of filtering and diversion after filtering.

[0049] Specifically, the butterfly-shaped sheet oil filter 2 is formed by folding multiple layers of stainless steel wire mesh. The traditional tubular oil filter 10 is a thin tube with small holes on the outer circle, and a stainless steel wire mesh with a certain filtering accuracy is wrapped. The total filtering area is determined by the diameter of the thin tube and the small holes on the thin tube. Since the tube diameter is relatively small, the number of small holes is also limited, the total filtering area cannot be increased, and the dirt holding capacity cannot be improved.

[0050] The designed structure is adjusted to a butterfly-shaped sheet oil filter 2, which is a frameless structure and is formed by folding multiple layers of stainless steel wire mesh. Through calculation and testing, the dirt holding capacity of the flow area is much greater than that of the existing tubular oil filter 10. At the same time, the butterfly-shaped sheet oil filter 2 installed separately will form a dirt holding chamber 26 with the pilot oil outlet housing 24 to further increase the dirt holding capacity.

[0051] like Figure 4 As shown, further, the electro-hydraulic flow servo valve further includes a valve sleeve 22 located in the middle, and the oil inlet throttle plug 21 is clamped between the pilot oil inlet housing 20 and the main valve sleeve 22 .

[0052] Furthermore, the electro-hydraulic flow servo valve also includes an oil lead-out housing 24 and two left and right end covers 23, each end cover 23 has two oil circuits connected to the nozzle 12 and the end of the valve core 14 respectively; the oil lead-out housing 24 has an L-shaped oil circuit, and the L-shaped oil circuit is connected to one of the oil circuits of the end cover 23.

[0053] Specifically, the electro-hydraulic flow servo valve further includes a nozzle seat 25, which serves as a base. The two nozzles 12 of the electro-hydraulic flow servo valve are both installed on the nozzle seat 25, and the nozzle seat 25 has an inclined flow channel connected to the L-shaped oil circuit.

[0054] The electro-hydraulic flow servo valve of the present application is provided with an external oil filter assembly, a corresponding oil inlet throttle plug 21 is added, and the pilot oil inlet housing 20, the valve sleeve 22, the pilot oil outlet housing 24, the left and right end covers 23 and the nozzle seat body 25 are uniquely modified to form a complete pilot oil passage, so that the pilot oil passage meets the requirements of first filtering and then diverting through the two throttle holes 11 to flow to the nozzle and the valve core 14, thereby meeting the functions of the original electro-hydraulic flow servo valve.

[0055] Preferably, the electro-hydraulic flow servo valve further includes an electromagnetic device 16 , which is disposed at the rear side of the nozzle seat body 25 .

[0056] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0057] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0058] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An electro-hydraulic flow servo valve with an external oil filter, characterized in that: include: A pilot oil inlet housing (20) has an oil filter groove (201) formed on its front end surface; An external oil filter assembly comprises a butterfly-shaped sheet oil filter (2) and an oil filter cover (3), wherein the oil filter cover (3) matches an oil filter groove (201); the butterfly-shaped sheet oil filter (2) is located in the oil filter groove (201) and is arranged on the rear end surface of the oil filter cover (3); the pilot oil inlet housing (20) and the oil filter cover (3) are both provided with a plurality of oil passages; Two oil inlet throttle plugs (21) are symmetrically arranged on the rear end surface of the pilot oil inlet housing (20), each of which is provided with a throttle hole (11). The pilot oil inlet housing (20), the oil filter cover (3) and the valve sleeve (22), the pilot oil outlet housing (24), the left and right end covers (23) and the oil path of the nozzle seat body (25) form a complete pilot oil passage; The pilot oil passage guides the two P S The oil entering the oil inlet (202) is collected and filtered by the butterfly-shaped sheet oil filter (2) before being divided into two symmetrical paths, each of which flows through a throttling hole (11) to a nozzle (12) and one end of a valve core (14); The oil filter assembly further comprises a double-layer sealing ring (1), wherein the double-layer sealing ring (1) clamps the butterfly-shaped sheet oil filter (2) to the rear end surface of the oil filter cover (3); and the rear half of the double-layer sealing ring (1) is used to separate the rear end surface of the oil filter tank (201) to form a dirt receiving cavity (26); A forward-concave storage and diversion cavity (28) is formed on the rear end surface of the rear half of the oil filter cover (3); The oil circuit of the pilot oil inlet housing (20) includes a pre-filter main oil inlet circuit (6), and the oil circuit of the oil filter cover (3) includes two filter cover oil outlet circuits (4) and two filter cover oil inlet circuits (5); The oil in the pre-filter main oil inlet circuit (6) is supplied from two P S The oil is collected at the oil inlet (202) and enters the oil filter cover (3) from two filter cover oil inlet passages (5), and flows out from two filter cover oil outlet passages (4) to two throttling holes (11) respectively.

2. The electro-hydraulic flow servo valve with an external oil filter as claimed in claim 1, characterized in that: The front end surfaces of the pilot oil inlet housing (20) and the oil filter cover (3) are both circular, and the oil filter cover (3) is located in the center of the pilot oil inlet housing (20); the front end surface of the oil filter cover (3) is flush with the front end surface of the pilot oil inlet housing (20).

3. The electro-hydraulic flow servo valve with an external oil filter as claimed in claim 2, characterized in that: The oil filter groove (201) is a stepped cylindrical hole, the oil filter cover (3) is in the shape of a stepped cylinder, and has a large diameter in the front half and a small diameter in the rear half; the double-layer sealing ring (1) is sleeved on the rear half of the oil filter cover (3).

4. The electro-hydraulic flow servo valve with an external oil filter as claimed in claim 1, characterized in that: The butterfly-shaped sheet oil filter (2) is formed by folding multiple layers of stainless steel wire mesh.

5. The electro-hydraulic flow servo valve with an external oil filter as claimed in claim 1, characterized in that: The electro-hydraulic flow servo valve further comprises a valve sleeve (22) located in the middle, and the oil inlet throttle plug (21) is clamped between the pilot oil inlet housing (20) and the main valve sleeve (22).

6. The electro-hydraulic flow servo valve with an external oil filter as claimed in claim 1, characterized in that: The electro-hydraulic flow servo valve further comprises an oil pilot housing (24) and two left and right end covers (23), each end cover (23) being provided with two oil paths respectively connected to the nozzle (12) and the end of the valve core (14); the oil pilot housing (24) being provided with an L-shaped oil path, and the L-shaped oil path being connected to one of the oil paths of the end cover (23).

7. The electro-hydraulic flow servo valve with an external oil filter as claimed in claim 6, characterized in that: The electro-hydraulic flow servo valve further comprises a nozzle seat body (25), two nozzles (12) are both mounted on the nozzle seat body (25), and the nozzle seat body (25) is provided with an oblique flow channel, wherein the oblique flow channel is connected to the L-shaped oil circuit.

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