A non-magnetic ring proportional pressure reducing electromagnetic valve for hydraulic system

Abstract

The application discloses a non-magnetic ring proportional pressure reducing electromagnetic valve for a hydraulic system, a first through hole, a second through hole and a first blind hole are formed in the valve body, a pressure relief hole and a pressure inlet hole are formed in the side wall of the valve body, the pressure relief hole and the pressure inlet hole are communicated with the first through hole, a working hole is radially formed in the side wall of the valve body, the inner end of the working hole is communicated with the first through hole, and the outer end extends to the outer surface of the valve body, a valve core is axially movably installed in the first through hole, and a fifth outer groove and a first annular protrusion are arranged on the outer periphery of the valve core, the first annular protrusion forms an annular gap with the inner wall of the first through hole, a coil assembly is arranged in the yoke, a stop iron is fixedly arranged in the yoke through a mounting plate, and a magnetic circuit optimization structure is arranged on the outer surface of the stop iron. The magnetic circuit optimization and the multiple anti-sticking and friction-reducing designs are integrated, the independent magnetic ring is cancelled, the structure is simplified, the electromagnetic force, the response speed and the service life of the electromagnetic valve are comprehensively improved, the processing difficulty is obviously reduced, and the application range of the electromagnetic valve is widened.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, and in particular to a proportional pressure reducing solenoid valve without magnetic isolation ring for use in hydraulic systems. Background Technology

[0002] Proportional pressure reducing solenoid valves are core components of pilot control systems for construction machinery. Through pilot control, they achieve "stepless speed change" and "precise control" of hydraulic actuators, making them key components for improving the operational performance of construction machinery.

[0003] Currently, most proportional pressure reducing solenoid valves of the same type, both domestically and internationally, adopt a platform or basin-type electromagnetic structure. To achieve a larger electromagnetic force, this type of structure typically employs a magnetic circuit breaker design. This design processes the external mating parts of the magnetically conductive moving iron (i.e., the moving component) into an independent part, and sets a non-magnetically conductive gap (usually an air gap) between this independent part and the moving iron to form a magnetic circuit breaker. This forces the magnetic lines of force to concentrate as much as possible across the effective cross-section of the moving iron after passing through the air gap, thereby obtaining a greater electromagnetic attraction force.

[0004] However, the existing technology has the following defects: (1) The assembly accuracy requirements are strict and it is easy to jam: The independent magnetic circuit breaker parts need to maintain a very high coaxiality with the moving iron, stationary iron and other components. In actual assembly, if the coaxiality is not good, the moving iron will be subjected to uneven lateral magnetic attraction during the movement, which is very easy to cause side swing and jamming, resulting in the failure of the solenoid valve and reduced reliability; (2) The structure is complex and the processing cost is high: The independent magnetic circuit breaker parts themselves are small in structure and have high precision requirements. Their processing, heat treatment and subsequent precision assembly all increase the manufacturing cost and process difficulty; (3) Friction and wear affect the service life: The moving iron and the independent mating parts are usually metal sliding friction pairs. Under long-term high-frequency reciprocating motion, wear is easy to occur, which not only affects the dynamic response speed, but also limits the overall service life of the solenoid valve. Summary of the Invention

[0005] The purpose of this invention is to provide a proportional pressure reducing solenoid valve without magnetic isolation ring for hydraulic systems, thereby solving the aforementioned problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention discloses a non-magnetic ring proportional pressure reducing solenoid valve for a hydraulic system, comprising a valve body, a valve core, an electromagnetic drive assembly, and a hydraulic feedback assembly. The valve body has an axially oriented first through hole, a second through hole, and a first blind hole. The valve body sidewall has a pressure relief hole and a pressure inlet hole, both of which communicate with the first through hole. The valve body sidewall has a radially oriented working hole, the inner end of which communicates with the first through hole, and the outer end of which extends to the outer surface of the valve body. The valve core is axially movable within the first through hole and has a fifth outer groove and a first annular protrusion on its outer periphery. The fifth outer groove is used to switch hydraulic passages. The first annular protrusion forms an annular gap with the inner wall of the first through hole. The front end of the valve core has a second blind hole, a third blind hole, and a fourth blind hole sequentially formed inwards. The electromagnetic drive assembly includes a mounting plate, a yoke, a pole shoe, a stop, an armature, an auxiliary stop, and a push rod. The yoke has a coil assembly inside, and the stop is fixed by the mounting plate. The yoke, pole shoe, armature, and stop are arranged inside the yoke, forming a closed magnetic circuit. The stop has a fifth and a sixth blind hole inside and a magnetic circuit optimization structure on its outer surface. The magnetic circuit optimization structure includes grooves and / or spiral grooves. The armature is disposed in the fifth blind hole, and a thin film is provided between the armature and the inner wall of the fifth blind hole. The auxiliary stop is disposed in the sixth blind hole. The push rod passes through the inner hole of the auxiliary stop and is interference-fitted to the armature at one end, and abuts against the end face of the valve core at the other end. The hydraulic feedback assembly includes a steel ball, a spring, and a steel ball seat. The steel ball is disposed in the third blind hole, and the steel ball seat is sealed and assembled in the first blind hole. One end of the spring is connected to the second blind hole, and the other end is connected to the steel ball seat. A variable hydraulic feedback area is formed between the steel ball and the hole wall of the third blind hole. The hole wall of the fourth blind hole has a first lateral hole, which communicates with the fifth outer groove.

[0008] Furthermore, the stop, the auxiliary stop, the armature, the yoke, the pole shoe, and the mounting plate are all made of magnetically conductive metal materials, while the valve body, the valve core, the push rod, and the spring are all made of non-magnetically conductive materials.

[0009] Furthermore, the surfaces of the stop, the auxiliary stop, the armature, the yoke, the pole shoe, and the mounting plate are all coated with a wear-resistant and corrosion-resistant coating.

[0010] Furthermore, a first inner groove is provided inside the valve body at the opening of the first blind hole, and an elastic retaining ring for the hole is provided in the first inner groove, which can limit the movement of the steel ball seat.

[0011] Furthermore, the valve body has a first outer groove, a second outer groove, and a third outer groove sequentially formed on its outer periphery. A first sealing ring is provided in the first outer groove, and a second sealing ring is provided in the third outer groove.

[0012] Furthermore, a third sealing ring is provided at the connection between the valve body and the mounting plate.

[0013] Furthermore, a fourth sealing ring is fitted between the steel ball seat and the first blind hole.

[0014] Furthermore, a shim is provided between the armature and the auxiliary stop, the shim can limit the armature, and the shim is made of non-magnetic material.

[0015] Furthermore, a third through hole is provided at the tail end of the stop, and a stop plug is interference-fitted into the third through hole. The stop plug is made of non-magnetic material.

[0016] Furthermore, a first pressure-inlet hole is provided on the outer periphery of the valve core, which is connected to the second blind hole to remove residual oil from the steel ball seat mounting cavity.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0018] 1. The magnetic ring-free proportional pressure reducing solenoid valve for hydraulic systems of the present invention eliminates the traditional independent magnetic ring by directly machining the optimized magnetic circuit structure on the outer surface of the stop iron. Its magnetic circuit efficiency is high and the magnetic energy utilization rate is significantly improved. It can make the solenoid valve structure compact and small in size, and greatly reduce the processing difficulty. It does not require the manufacturing and assembly of high-precision independent small parts, which is conducive to achieving quality stability in mass production.

[0019] 2. The non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems of the present invention forms a low-friction moving pair by setting a friction-reducing diaphragm between the armature and the stop, with a very small friction coefficient, which effectively reduces motion resistance and wear; at the same time, combined with the annular protrusion design at the front end of the valve core, it can balance the radial hydraulic pressure, significantly improve the solenoid valve's anti-side sway and anti-jamming ability, and ensure smooth pressure regulation process, excellent pressure regulation performance, and rapid dynamic response.

[0020] 3. The non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems of the present invention, by setting up a hydraulic feedback component, uses a steel ball and a blind hole in the valve core to form a variable feedback area, which reduces the machining quality requirements of the precision feedback cavity in the valve core, especially under high working pressure conditions, significantly reducing the machining difficulty; the steel ball can roll flexibly in the blind hole, which greatly reduces the impact of friction on the movement of the valve core, effectively avoids performance degradation or failure caused by valve core jamming, and improves the reliability of pressure regulation.

[0021] The non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems of the present invention, through its unique overall structure, achieves a significant improvement in comprehensive performance compared with existing technical solutions under the same size specifications. It has a larger electromagnetic force, longer service life, faster response speed, and significantly reduced processing and assembly difficulty. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems according to the present invention.

[0024] Figure 2 This is a schematic diagram of the valve body in the non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems according to the present invention.

[0025] Figure 3 This is a schematic diagram of the valve core in the non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems according to the present invention.

[0026] Figure 4 This is a schematic diagram of the retaining iron structure in the non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems according to the present invention.

[0027] Explanation of reference numerals in the attached drawings: 1-Valve body; 2-First sealing ring; 3-Filter screen; 4-Second sealing ring; 5-Third sealing ring; 6-Mounting plate; 7-Yoke; 8-Coil assembly; 9-Pole shoe; 10-Stop plug; 11-Stop; 12-Armature; 13-Diaphragm; 14-Gasket; 15-Push rod; 16-Valve core; 17-Steel ball; 18-Spring; 19-Fourth sealing ring; 20-Steel ball seat; 21-Elastic retaining ring for the hole; 22-Pressure relief hole; 23-First through hole; 24- Working hole; 25-Pressure inlet hole; 26-Second through hole; 27-First blind hole; 28-First inner groove; 29-First outer groove; 30-Second outer groove; 31-Third outer groove; 32-Fourth outer groove; 33-First pressure inlet hole; 34-Fifth outer groove; 35-First annular protrusion; 36-Second blind hole; 37-Third blind hole; 38-First lateral hole; 39-Fourth blind hole; 40-Third through hole; 41-Fifth blind hole; 42-Groove; 43-Spiral groove; 44-Sixth blind hole. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of this invention, it should be understood that the terms "length," "width," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] like Figures 1 to 4 As shown, the non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems in this embodiment includes a valve body 1, a valve core 16, an electromagnetic drive assembly, and a hydraulic feedback assembly, as follows: Figure 2 As shown, the valve body 1 has a first through hole 23, a second through hole 26 and a first blind hole 27 axially arranged inside. The side wall of the valve body 1 has a pressure relief hole 22 and a pressure inlet hole 25, both of which are connected to the first through hole 23. Preferably, a filter screen 3 is provided at the inlet of the pressure inlet hole 25 to filter the hydraulic oil entering the pressure inlet hole 25 and prevent contaminants from damaging the valve core. At the same time, a working hole 24 is radially arranged on the side wall of the valve body 1, and the inner end of the working hole 24 is connected to the first through hole 23, and the outer end extends to the outer surface of the valve body 1. The valve core 16 is axially movable and installed in the first through hole 23. When the valve core 16 moves left and right, it can switch the hydraulic passage to realize the function of a solenoid valve.

[0033] And, as Figure 3 As shown, the valve core 16 has a fifth outer groove 34 and a first annular protrusion 35 on its outer periphery. When the valve core 16 moves left and right, the fifth outer groove 34 is used to switch the hydraulic passage. The first annular protrusion 35 forms an annular gap with the inner wall of the first through hole 23. At this time, when the working medium enters the annular gap, it can balance the radial oil pressure on the valve core 16, thereby effectively preventing the valve core 16 from swaying when it moves and reducing the frictional resistance between it and the valve body 1. The front end of the valve core 16 is provided with a second blind hole 36, a third blind hole 37 and a fourth blind hole 39 in sequence.

[0034] In this embodiment, the electromagnetic drive assembly includes a mounting plate 6, a yoke 7, pole shoes 9, a stop 11, an armature 12, an auxiliary stop, and a push rod 15. The yoke 7 houses a coil assembly 8. The interference fit between the yoke 7 and the mounting plate 6 secures and protects the coil assembly 8. Simultaneously, the stop 11 is fixedly mounted inside the yoke 7 via the mounting plate 6. The yoke 7, pole shoes 9, armature 12, and stop 11 together form a closed magnetic circuit. Figure 4 As shown, the stop 11 has a fifth blind hole 41 and a sixth blind hole 44 inside, and a magnetic circuit optimization structure on its outer surface. This magnetic circuit optimization structure can optimize the magnetic circuit design and generate greater electromagnetic force. Specifically, the magnetic circuit optimization structure includes a groove 42 and / or a spiral groove 43. The armature 12 is set in the fifth blind hole 41, and a thin film 13 is provided between the outer diameter of the armature 12 and the inner wall of the fifth blind hole 41. The thin film 13 can reduce the friction between moving parts and extend the working life of the solenoid valve. The auxiliary stop is set in the sixth blind hole 44. The push rod 15 passes through the inner hole of the auxiliary stop and one end is interference-fitted with the armature 12, and the other end abuts against the end face of the valve core 16 to realize the transmission function.

[0035] Furthermore, the hydraulic feedback assembly includes a steel ball 17, a spring 18, and a steel ball seat 20. The steel ball 17 is disposed in the third blind hole 37, and a variable hydraulic feedback area is formed between the steel ball 17 and the wall of the third blind hole 37. The steel ball seat 20 is sealed and assembled in the first blind hole 27. One end of the spring 18 is connected in the second blind hole 36, and the other end is connected to the steel ball seat 20. That is, the spring 18 is housed in the second blind hole 36, with one end acting on the valve core 16 and the other end acting on the steel ball seat 20. At this time, the spring 18 provides the valve core reset force, and the steel ball 17 senses the output pressure and generates feedback force through the hydraulic feedback area. The two together with the electromagnetic force constitute a force balance mechanism to realize linear pressure regulation. The wall of the fourth blind hole 39 is provided with a first lateral hole 38, which is connected to the fifth outer groove 34.

[0036] The stop 11, auxiliary stop, armature 12, yoke 7, pole shoe 9, and mounting plate 6 are all made of magnetically conductive metal, while the valve body 1, valve core 16, push rod 15, and spring 18 are all made of non-magnetically conductive material. Preferably, the surfaces of the stop 11, auxiliary stop, armature 12, yoke 7, pole shoe 9, and mounting plate 6 are all coated with a wear-resistant and corrosion-resistant coating.

[0037] Furthermore, a first inner groove 28 is provided inside the valve body 1 at the opening of the first blind hole 27, and an elastic retaining ring 21 for the hole is provided in the first inner groove 28. The elastic retaining ring 21 for the hole can limit the movement of the steel ball seat 20.

[0038] In addition, the valve body 1 has a first outer groove 29, a second outer groove 30, a third outer groove 31, and a fourth outer groove 32 sequentially formed on its outer periphery. A first sealing ring 2 is installed in the first outer groove 29 to establish a seal between the pressure inlet 25 and the working hole 24. Simultaneously, a second sealing ring 4 is installed in the third outer groove 31 to establish a seal between the pressure inlet 25 and the pressure relief hole 22. Furthermore, a third sealing ring 5 is installed at the connection between the valve body 1 and the mounting plate 6. Also, a fourth sealing ring 19 is assembled between the ball seat 20 and the first blind hole 27 to establish a seal at the process hole of the valve body 1, preventing leakage from the pressure inlet 25 at this location.

[0039] In this embodiment, a shim 14 is provided between the armature 12 and the auxiliary stop. The shim 14 can limit the armature 12, control the activity area of ​​the armature 12, and adjust the voltage regulation curve. Preferably, the shim 14 is made of non-magnetic material.

[0040] Meanwhile, a third through hole 40 is provided at the tail end of the stop 11. A stop plug 10 is interference-fitted in the third through hole 40. The interference fit between the third through hole 40 and the stop plug 10 can form a seal to prevent the internal pressure from leaking from the tail end of the stop 11. Preferably, the stop plug 10 is made of non-magnetic material.

[0041] In addition, a first pressure-inlet hole 33 is provided on the outer periphery of the valve core 16. The first pressure-inlet hole 33 is connected to the second blind hole 36 to remove residual oil in the mounting cavity of the steel ball seat 20 and avoid pressure residue causing the solenoid valve to malfunction.

[0042] In this embodiment, the proportional pressure reducing solenoid valve for hydraulic systems without magnetic isolation rings operates as follows: When the coil assembly 8 is energized, current flows through the coil assembly 8, generating a magnetic field in the closed magnetic circuit formed by the yoke 7, pole shoe 9, armature 12, and stop 11. Under the action of electromagnetic force, the armature 12 moves towards the auxiliary stop. At this time, the armature 12 pushes the valve core 16 through the push rod 15, causing it to compress the spring 18 and move to the right. During the movement of the valve core 16, the axial position of its fifth outer groove 34 changes. First, it gradually closes the connection between the pressure relief hole 22 and the working hole 24, and then opens the connection between the working hole 24 and the pressure inlet hole 25. High-pressure oil flows in from the pressure inlet hole 25, passes through the fifth outer groove 34, and is output from the working hole 24, driving the downstream actuator. At the same time, the output pressure of the working hole 24 is transmitted to the third blind hole 37 through the first lateral hole 38 and the fourth blind hole 39, acting on the hydraulic feedback area formed by the steel ball 17, generating a hydraulic feedback force proportional to the output pressure and directed to the left. At this time, the valve core 16 is subjected to three forces: an electromagnetic thrust to the right, a spring force 18 to the left, and a hydraulic feedback force to the left. When these three forces reach dynamic equilibrium, the valve core 16 stops at a certain position. Since the electromagnetic force is proportional to the input current and the hydraulic feedback force is proportional to the output pressure, the equilibrium position of the valve core 16 determines the magnitude of the output pressure, and this pressure has a linear proportional relationship with the input current, achieving precise proportional pressure reduction control. During this process, the oil enters the annular gap formed by the first annular protrusion 35 and the inner wall of the first through hole 23, balancing the oil pressure radially acting on the valve core 16, effectively preventing lateral swaying and ensuring smooth movement.

[0043] When the coil assembly 8 is de-energized, the electromagnetic force disappears, and the reset force of the spring 18 becomes dominant. The spring 18 pushes the valve core 16 to reset to the left, and then drives the armature 12 to move away from the auxiliary stop through the push rod 15. The movement of the valve core 16 causes the axial position of the fifth outer groove 34 to change in the opposite direction. First, the connection between the working hole 24 and the pressure inlet hole 25 is cut off, and then the connection between the working hole 24 and the pressure relief hole 22 is opened. The residual pressure oil in the working hole 24 is discharged back to the oil tank through the pressure relief hole 22 via the fifth outer groove 34, and the actuator is depressurized. As the pressure in the working hole 24 decreases, the hydraulic feedback force acting on the steel ball 17 decreases rapidly. The valve core 16 is fully reset under the action of the spring force 18 until it is limited by the mechanical structure, and the solenoid valve returns to its initial state. During the reset process, the oil that may remain in the mounting cavity of the steel ball seat 20 can be discharged through the first pressure inlet hole 33 to avoid back pressure affecting the reset response of the valve core 16.

[0044] The non-magnetic ring proportional pressure reducing solenoid valve for hydraulic systems of the present invention, through its unique overall structure, achieves a significant improvement in comprehensive performance compared with existing technical solutions under the same size specifications. It has a larger electromagnetic force, longer service life, faster response speed, and significantly reduced processing and assembly difficulty.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A proportional pressure reducing solenoid valve without magnetic isolation ring for use in a hydraulic system, characterized in that, The system includes a valve body (1), a valve core (16), an electromagnetic drive assembly, and a hydraulic feedback assembly. The valve body (1) has a first through hole (23), a second through hole (26), and a first blind hole (27) axially arranged inside. The valve body (1) has a pressure relief hole (22) and a pressure inlet hole (25) on its side wall. The pressure relief hole (22) and the pressure inlet hole (25) are both connected to the first through hole (23). The valve body (1) has a working hole (24) radially arranged on its side wall. The inner end of the working hole (24) is connected to the first through hole (23), and the outer end extends to the outer surface of the valve body (1). The valve core (16) is axially movable and installed in the first through hole (23). The valve core (16) has a fifth outer groove (34) and a first annular protrusion (35) on its outer periphery. The fifth outer groove (34) is used to switch the hydraulic passage. The first annular protrusion (35) forms an annular gap with the inner wall of the first through hole (23). The valve core (16) has a second blind hole (36), a third blind hole (37) and a fourth blind hole (39) opened in sequence on its front end. The electromagnetic drive assembly includes a mounting plate (6), a yoke (7), a pole shoe (9), a stop (11), an armature (12), an auxiliary stop and a push rod (15). The yoke (7) has a coil assembly (8) inside. The stop (11) is fixedly installed inside the yoke (7) by the mounting plate (6). The yoke (7), pole shoe (9), armature (12), and stop (11) together form a closed magnetic circuit. The stop (11) has a fifth blind hole (41) and a sixth blind hole (44) inside and a magnetic circuit optimization structure on its outer surface. The magnetic circuit optimization structure includes a groove (42) and / or a spiral groove (43). The armature (12) is disposed in the fifth blind hole (41), and a thin film (13) is provided between the armature (12) and the inner wall of the fifth blind hole (41). The auxiliary stop is disposed in the sixth blind hole (44). The push rod (15) passes through the inner hole of the auxiliary stop and is interference-fitted to the armature (12) at one end. One end abuts against the end face of the valve core (16). The hydraulic feedback assembly includes a steel ball (17), a spring (18), and a steel ball seat (20). The steel ball (17) is disposed in the third blind hole (37). The steel ball seat (20) is sealed and assembled in the first blind hole (27). One end of the spring (18) is connected in the second blind hole (36), and the other end is connected to the steel ball seat (20). A variable hydraulic feedback area is formed between the steel ball (17) and the hole wall of the third blind hole (37). The hole wall of the fourth blind hole (39) is provided with a first lateral hole (38). The first lateral hole (38) is connected to the fifth outer groove (34).

2. The non-magnetic ring proportional pressure reducing solenoid valve for a hydraulic system according to claim 1, characterized in that, The stop (11), the auxiliary stop, the armature (12), the yoke (7), the pole shoe (9) and the mounting plate (6) are all made of magnetic metal material, while the valve body (1), the valve core (16), the push rod (15) and the spring (18) are all made of non-magnetic material.

3. The non-magnetic ring proportional pressure reducing solenoid valve for a hydraulic system according to claim 1, characterized in that, The surfaces of the stop (11), the auxiliary stop, the armature (12), the yoke (7), the pole shoe (9), and the mounting plate (6) are all coated with a wear-resistant and corrosion-resistant coating.

4. A proportional pressure reducing solenoid valve for a hydraulic system without magnetic isolation ring according to claim 1, characterized in that, The valve body (1) is provided with a first inner groove (28) inside and at the opening of the first blind hole (27). An elastic retaining ring (21) for the hole is provided in the first inner groove (28). The elastic retaining ring (21) for the hole can limit the position of the steel ball seat (20).

5. A proportional pressure reducing solenoid valve for a hydraulic system without magnetic isolation ring according to claim 1, characterized in that, The valve body (1) has a first outer groove (29), a second outer groove (30) and a third outer groove (31) sequentially opened on its outer periphery. A first sealing ring (2) is provided in the first outer groove (29), and a second sealing ring (4) is provided in the third outer groove (31).

6. A proportional pressure reducing solenoid valve without magnetic isolation ring for a hydraulic system according to claim 1, characterized in that, A third sealing ring (5) is provided at the connection between the valve body (1) and the mounting plate (6).

7. A proportional pressure reducing solenoid valve for a hydraulic system without magnetic isolation ring according to claim 1, characterized in that, A fourth sealing ring (19) is fitted between the steel ball seat (20) and the first blind hole (27).

8. A proportional pressure reducing solenoid valve for a hydraulic system without magnetic isolation ring according to claim 1, characterized in that, A shim (14) is provided between the armature (12) and the auxiliary stop, the shim (14) can limit the armature (12), and the shim (14) is made of non-magnetic material.

9. A proportional pressure reducing solenoid valve for a hydraulic system without magnetic isolation ring according to claim 1, characterized in that, The end of the stop (11) is provided with a third through hole (40), and a stop cover (10) is interference-fitted in the third through hole (40). The stop cover (10) is made of non-magnetic material.

10. A proportional pressure reducing solenoid valve for a hydraulic system without a magnetic isolation ring according to any one of claims 1-9, characterized in that, The valve core (16) has a first pressure hole (33) on its outer periphery. The first pressure hole (33) is connected to the second blind hole (36) to remove residual oil in the mounting cavity of the steel ball seat (20).

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