Permanent magnet pressure compensator and control method

Abstract

The invention discloses a permanent magnet pressure compensator and a control method and relates to the technical field of hydraulic pressure. The iron core abuts against the step of the valve body through the guide sleeve. The permanent magnet fixedly sleeves the outer side of the guide sleeve and is connected with the step of the iron core; the armature is slidably arranged in the guide sleeve, and a magnetic isolation sheet is arranged between the armature and the iron core; the push rod is slidably arranged in the iron core, one end of the push rod is fixedly connected with the armature, and the other end of the push rod extends into the P2 cavity and is attached to the compensator valve element. Magnetic lines generated by the permanent magnet on the guide sleeve form a closed loop through the armature, the iron core, the housing and the valve body, force in the axial direction of the armature is generated on the armature, when oil enters, pressure P0 enters the cavity P1 through a step on the valve body, meanwhile, hydraulic oil flows to the right end face of the compensator valve element, and resultant force of leftward thrust FP1, F and FP2 is generated and compared with the FP1. The pressure difference value before and after the valve body loads the valve port is a constant value. If the opening degree of the load valve port of the valve body is not changed and the pressure difference value is not changed, the flow of the execution element is stable and not changed.

Description

Technical Field

[0001] The present invention relates to hydraulic control technology, and particularly to a permanent magnet pressure compensator and a control method thereof. Background Art

[0002] A pressure compensator is usually applied in a load-sensing proportional multi-way directional control valve to maintain stable operation of the system and improve its performance. By automatically adjusting and balancing the fluid pressure, the pressure compensator can effectively reduce the pressure fluctuations in the system, stabilize the pressure difference at the load valve port, and make the flow rate of the control actuator less affected by load fluctuations. As Figure 6-7 shown in: In the figure, A1 is the valve body, A2 is the compensator plug, A3 is the spring, A4 is the compensator spool, A5 is the compensator valve port, A6 is the path of the hydraulic oil inside the compensator spool, and A7 is the step.

[0003] The inlet pressure P0 enters the P1 chamber (pressure is P1) through the step on the valve body. P1 is the pressure before the load valve port of the valve body. At the same time, the hydraulic oil reaches the right end face of the compensator through the path, generating a force FP1, which pushes the compensator spool to move leftward. There is a spring force F at the left end of the compensator, and a force FP2 generated by the hydraulic oil P2 fed back from the load end. The combined force of the spring force and FP2 is compared with FP1. When the load becomes smaller, F + FP2 < FP1, the compensator spool moves leftward, the compensator valve port decreases, the pressure loss at the step of P0 increases, P1 decreases until the force values at both ends of the compensator are balanced; when the load becomes larger, F + FP2 > FP1, the compensator spool moves rightward, the compensator valve port increases, the pressure loss at the step of P0 decreases, P1 increases until the force values at both ends of the compensator are balanced. The pressure difference before and after the load valve port of the valve body is determined by the spring force F. The spring force F = kx, where k is the spring stiffness and x is the spring compression amount. As the position of the compensator spool changes, the spring compression amount changes accordingly, and the spring force F also changes. When the opening of the load valve port of the valve body remains unchanged, the flow rate of the valve port changes with the change of the spring force, making the flow rate of the control actuator unstable. Summary of the Invention

[0004] In view of the above problems, the present invention provides a permanent magnet pressure compensator and a control method with a compact structure, which can stably control the valve port flow rate based on the original valve body.

[0005] The technical solution of the present invention is: A permanent magnet pressure compensator, comprising: A valve body having an inlet port and a load valve port, and a P1 chamber and a P2 chamber formed inside the valve body; A compensator spool slidably arranged inside the valve body to adjust the pressure of the P1 chamber; A housing hermetically and fixedly arranged at the end of the valve body; there is a valve body step between the inner cavity of the housing and the P2 chamber; The iron core is supported on the valve body step through a guide sleeve; a distance is set between the inner side wall of the guide sleeve and the iron core; A permanent magnet, a fixed sleeve is arranged outside the guide sleeve and connected to the step of the iron core; The armature is slidably arranged in the guide sleeve, and a magnetic isolation sheet is provided between the armature and the iron core; The push rod is slidably arranged in the iron core, one end of which is fixedly connected to the armature, and the other end of which extends into the P2 cavity and fits with the compensator valve core.

[0006] Specifically, the iron core is provided with a chamfer a near the end corner of the armature, so that the end of the iron core forms a conical surface.

[0007] Specifically, the chamfer angle a is 35° to 36°.

[0008] Specifically, the iron core is provided with a basin opening near the armature end.

[0009] Specifically, a plane b is provided between the basin mouth and the conical surface.

[0010] Specifically, the value range of the plane b is 0.1-0.2 mm.

[0011] Specifically, a plurality of sealing grooves arranged at intervals are provided on the outer circumferential surface of the iron core; An adapted sealing ring 1 is provided in the sealing groove; The guide sleeve and the iron core are sealed by a sealing ring.

[0012] Specifically, the thickness of the magnetic isolation sheet is 0.5 mm to 0.6 mm.

[0013] Specifically, the cover shell and the end face of the valve body are sealed by a second sealing ring, and are fixedly connected thereto by a plurality of connecting pieces.

[0014] A control method for a permanent magnetic pressure compensator comprises the following steps: In the initial state, the magnetic field generated by the permanent magnet generates a thrust F on the armature and push rod combination toward the compensator valve core, causing the armature and push rod combination to fit on the iron core, and the push rod end face to rest on the front end face of the compensator valve core. The force exerted by the push rod on the compensator valve core is F, causing the compensator valve core to be in the initial position; When oil is flowing in, the pressure at the oil inlet is P0, which enters the P1 chamber through the step in the valve body. At the same time, the hydraulic oil enters the rear end face of the compensator valve core, generating a thrust FP1 in the direction of the push rod. The hydraulic oil P2 fed back from the load end generates a force FP2 on the front end face of the compensator valve core. The force F+FP2 at the front end of the compensator valve core is compared with the force FP1 at the rear end of the compensator valve core. When F+FP2<FP1, the compensator valve core moves toward the push rod, the compensator valve port opening decreases, the pressure loss increases, the oil pressure in the P1 chamber decreases, and further causes FP1 to decrease until the forces at both ends of the compensator valve core are balanced; When F+FP2=FP1, the forces at both ends of the compensator spool are balanced and the compensator spool is stationary; When F+FP2>FP1, the compensator valve core moves toward the oil inlet, the compensator valve port opening increases, the pressure loss decreases, and the oil pressure in the P1 chamber increases, further causing FP1 to increase until the forces at both ends of the compensator valve core are balanced.

[0015] Beneficial effects of the present invention: The permanent magnet on the guide sleeve generates magnetic flux lines that form a closed circuit through the armature, core, housing, and valve body, exerting an axial force on the armature. Because the magnetic flux lines tend to close along the path of minimal magnetic resistance and tend to shorten the magnetic flux path to reduce magnetic resistance, the force is directed toward the point where the air gap is minimized (i.e., toward the core). When oil is introduced, pressure P0 enters chamber P1 (at pressure P1) via the step in the valve body. Simultaneously, hydraulic oil reaches the right end of the compensator spool, generating a leftward thrust force FP1. The combined force of F and FP2 (the force generated by hydraulic fluid P2 fed back from the load side) is compared to FP1. At this point, the pressure differential across the valve body's load port is determined by F. Given the fixed material and size of the permanent magnet, the generated magnetic field strength remains constant, the electromagnetic force on the armature remains constant, and the force exerted by the armature remains constant. Therefore, the pressure differential across the valve body's load port remains constant. If the valve body's load port opening remains constant, and the pressure differential remains constant, the flow rate of the actuator remains stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the initial state of the present invention, Figure 2 It is a schematic diagram of the core cone structure; Figure 3 yes Figure 2 Schematic diagram of the enlarged structure of the circled area; Figure 4 Schematic diagram of the compensator valve core of the present invention moving to the left until the compensator valve port is closed; Figure 5 It is a graph showing the external output force F of the armature and push rod assembly and the armature displacement; Figure 6 This is a schematic diagram of the structure of the valve opening state in the background technology; Figure 7 This is a schematic diagram of the structure of the valve port in the closed state in the background technology; In the figure, 100 is the valve body, 200 is the compensator valve core, 300 is the cover, 400 is the iron core, 410 is the cone surface, 420 is the basin mouth, 500 is the guide sleeve, 600 is the permanent magnet, 700 is the armature, 800 is the magnetic isolation plate, and 900 is the push rod. DETAILED DESCRIPTION

[0017] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0018] In the description of the present invention, it should be understood that terms such as "upper," "lower," "left," "right," "vertical," and "horizontal" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are used solely to facilitate and simplify the description of the present invention and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0019] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0020] A permanent magnetic pressure compensator, comprising: The valve body 100 has an oil inlet and a load valve port, as well as a P1 cavity and a P2 cavity formed inside the valve body; The compensator valve core 200 is slidably disposed in the valve body 100 to adjust the pressure of the P1 chamber; The cover 300 is sealed and fixedly arranged at the end of the valve body 100; a valve body step is provided between the inner cavity of the cover 300 and the P2 cavity; The housing 300 is sealed to the end face of the valve body 100 by a sealing ring 2 and fixedly connected to the valve body 100 by a plurality of connectors. In this embodiment, the housing, armature, and iron core are all made of magnetic conductive materials (such as electromagnetic pure iron) to form a magnetic circuit, while the magnetic isolation plate and push rod are non-magnetic.

[0021] The iron core 400 rests against the valve body step through the guide sleeve 500; a distance is provided between the inner wall of the guide sleeve 500 and the iron core 400; The inner bores of core 400 and guide sleeve 500 are the same size, with a negative tolerance for core 400 and a positive tolerance for guide sleeve 500. The inner cavity of guide sleeve 500 communicates with cavity P2. A sealing ring is installed on core 400, and the inner cavity of guide sleeve 500 is not connected to the inner cavity of housing 300. Guide sleeve 500 is made of stainless steel and has an outwardly extending beveled edge to prevent cutting during installation. The core is made of a magnetically conductive material, such as pure electromagnetic iron, to form a magnetic circuit.

[0022] The outer circumferential surface of the iron core 400 is provided with a plurality of sealing grooves arranged at intervals; an adaptive sealing ring 1 is provided in the sealing groove; and the guide sleeve 500 and the iron core 400 are sealed by the sealing ring 1.

[0023] The permanent magnet 600 is fixedly sleeved outside the guide sleeve 500 and connected to the step of the iron core 400; The permanent magnet 600 is tightly attached to the step of the iron core 400. The permanent magnet has a stable magnetic field. When it is close to the iron core, the iron core is magnetized, forming a magnetic field with opposite poles to the permanent magnet, thereby generating an attractive force. The armature 700 is slidably disposed in the guide sleeve 500, and a magnetic isolation plate 800 is provided between the armature and the iron core; The armature 700 is made of non-magnetic material (such as 304 stainless steel), and the magnetic isolation plate 800 has no fixed connection with the armature 700 and the iron core 400 and can move freely. In order to enable the armature 700 to output an approximately constant force within a certain displacement, the thickness of the magnetic isolation plate needs to be controlled at 0.5mm to 0.6mm.

[0024] The thickness of the magnetic isolation sheet 800 is 0.5mm-0.6mm, and is used to control the magnetic flux density distribution of the working air gap. If it is too thin, it may not be able to effectively isolate the magnetic field, and if it is too thick, the magnetic field will be excessively weakened.

[0025] The push rod 900 is made of 316 stainless steel, is non-magnetic, and is slidably disposed in the iron core 400 . One end is fixedly connected to the armature 700 , and the other end extends into the P2 cavity and fits with the compensator valve core 200 .

[0026] The iron core 400 is provided with a chamfer a at an end corner near the armature 700, so that the end of the iron core 400 forms a tapered surface 410. The chamfer a is 35° to 36°.

[0027] The iron core 400 is provided with a basin opening 420 near the end of the armature 700 .

[0028] A plane b is defined between the basin opening 420 and the conical surface 410 .

[0029] The value range of plane b is 0.1-0.2mm.

[0030] like Figure 2 As shown, the left side of the core 400 is provided with a chamfer a, and the junction between the basin mouth 420 of the core 400 and the conical surface 410 is not a sharp corner, but a small section of plane b, so that the armature 700 is in the stroke C ( Figure 1 In the state, within the displacement (the horizontal distance between the right end surface of the armature 700 and the left end surface of the iron core 400), the output force has a horizontal characteristic, that is, a stable characteristic.

[0031] The magnetic lines of force generated by the permanent magnet 600 form a closed loop through the armature 700, the core 400, and the housing 300, and exert a force on the armature 700 along the axial direction of the armature 700. Within the effective stroke, the output force of the armature 700 is a constant value.

[0032] The shape of the opening 420 of the core 400 (i.e., the air gap structure between the core 400 and the armature 700) is one of the design factors that determines the electromagnetic force characteristics (linearity, force magnitude, etc.). If the end of the core 400 is flat, the air gap is uniform. However, because the force increases sharply as the air gap decreases, the force-displacement curve is highly nonlinear. Therefore, we design the opening angle to be conical, with steps at the opening to form a segmented air gap. This step-by-step control controls the magnetic flux distribution and provides a nearly linear force output. The angle is typically between 30° and 60°. Smaller angles improve linearity, but the initial output force decreases, requiring a balance based on demand. If plane b becomes sharp, the force-displacement curve will not have linear characteristics (such as in a switching electromagnet). If it is too large, it will tend to be a flat opening, and the force-displacement curve will be highly nonlinear. The final angle and step height must be determined through simulation and experimentation.

[0033] For example, the force unit in 4 is N, and the displacement unit is 10 -2 At zero displacement, the armature is at its far right end. At 1.2 mm, the front end of the armature just enters the core opening. Between 0 and 1.4 mm, the output force stabilizes at around 24 N, with a small error of approximately 1 N between the maximum and minimum values. This effectively controls the valve body load, keeping the pressure differential across the valve port essentially constant, and thus maintaining a stable flow rate through the actuator.

[0034] A control method for a permanent magnetic pressure compensator comprises the following steps: In the initial state, the magnetic field generated by the permanent magnet 600 exerts a thrust F on the armature 700 and push rod 900 assembly toward the compensator valve core 200, causing the armature 700 and push rod 900 assembly to adhere to the iron core 400. The end face of the push rod 900 abuts against the front face of the compensator valve core 200. The force exerted by the push rod 900 on the compensator valve core 200 is F, placing the compensator valve core 200 in the initial position. When oil is flowing in, the pressure at the oil inlet is P0. The oil enters the P1 chamber (pressure P1) through the step in the valve body 100. Simultaneously, the hydraulic oil enters the rear end face of the compensator spool 200, generating a thrust FP1 toward the push rod 900. The hydraulic oil P2 fed back from the load end exerts a force FP2 on the front end face of the compensator spool 200. The force F+FP2 at the front end of the compensator spool 200 is compared with the force FP1 at the rear end of the compensator spool 200. When F+FP2<FP1, the compensator valve core 200 moves toward the push rod 900, the compensator valve port opening decreases, the pressure loss increases, the oil pressure in the P1 chamber decreases, and further causes FP1 to decrease until the forces at both ends of the compensator valve core 200 are balanced. When F+FP2=FP1, the forces at both ends of the compensator spool 200 are balanced, and the compensator spool 200 is stationary. When F+FP2>FP1, the compensator valve core 200 moves toward the oil inlet ( Figure 1 The compensator valve port opening increases, the pressure loss decreases, and the oil pressure in the P1 chamber increases, which further increases FP1 until the forces at both ends of the compensator valve core are balanced.

[0035] Regarding the content disclosed in this case, the following points need to be explained: (1) The drawings of the embodiments disclosed in this case only involve the structures involved in the embodiments disclosed in this case. Other structures can refer to the general design; (2) In the absence of conflict, the embodiments and features of the embodiments disclosed in this case may be combined with each other to form new embodiments; The above are only specific implementation methods disclosed in this case, but the protection scope of this disclosure is not limited thereto. The protection scope disclosed in this case should be based on the protection scope of the claims.

Claims

1. A permanent magnetic pressure compensator, characterized in that: include: A valve body (100) having an oil inlet and a load valve port, and a P1 cavity and a P2 cavity formed inside the valve body; A compensator valve core (200) is slidably disposed in the valve body (100) to adjust the pressure of the P1 chamber; A cover shell (300) is sealed and fixedly arranged at the end of the valve body (100); a valve body step is provided between the inner cavity of the cover shell (300) and the P2 cavity; The iron core (400) is pressed against the valve body step via a guide sleeve (500); a distance is provided between the inner side wall of the guide sleeve (500) and the iron core (400); A permanent magnet (600), a fixed sleeve arranged outside the guide sleeve (500) and connected to the step of the iron core (400); An armature (700) is slidably disposed in the guide sleeve (500), and a magnetic isolation plate (800) is provided between the armature and the iron core; The push rod (900) is slidably arranged in the iron core (400), one end of which is fixedly connected to the armature (700), and the other end of which extends into the P2 cavity and fits with the compensator valve core (200).

2. A permanent magnetic pressure compensator according to claim 1, characterized in that: The iron core (400) is provided with a chamfer a near the end corner of the armature (700), so that the end of the iron core (400) forms a conical surface (410).

3. A permanent magnetic pressure compensator according to claim 2, characterized in that: The chamfer angle a is 35° to 36°.

4. A permanent magnetic pressure compensator according to claim 2, characterized in that: The iron core (400) is provided with a basin opening (420) at an end close to the armature (700).

5. The permanent magnetic pressure compensator according to claim 4, characterized in that: A plane b is provided between the basin mouth (420) and the conical surface (410).

6. The permanent magnetic pressure compensator according to claim 5, characterized in that: The value range of the plane b is 0.1-0.2 mm.

7. The permanent magnetic pressure compensator according to claim 1, characterized in that: The outer circumferential surface of the iron core (400) is provided with a plurality of sealing grooves arranged at intervals; An adapted sealing ring 1 is provided in the sealing groove; The guide sleeve (500) and the iron core (400) are sealed by a sealing ring.

8. The permanent magnetic pressure compensator according to claim 1, characterized in that: The thickness of the magnetic isolation sheet (800) is 0.5 mm to 0.6 mm.

9. The permanent magnetic pressure compensator according to claim 4, characterized in that: The cover shell (300) and the end surface of the valve body (100) are sealed by a second sealing ring and are fixedly connected thereto by a plurality of connecting pieces.

10. A method for controlling a permanent magnetic pressure compensator, comprising the permanent magnetic pressure compensator of claim 1, comprising the following steps: In the initial state, the magnetic field generated by the permanent magnet (600) generates a thrust F on the combination of the armature (700) and the push rod (900) in the direction of the compensator valve core (200), so that the armature 700 and the push rod 900 combination fits on the iron core (400), the end face of the push rod (900) abuts against the front end face of the compensator valve core (200), and the force exerted by the push rod 900 on the compensator valve core 200 is F, so that the compensator valve core (200) is in the initial position; When oil is fed in, the pressure at the oil inlet is P0, and the oil enters the P1 cavity through the step in the valve body (100). At the same time, the hydraulic oil enters the rear end surface of the compensator valve core (200), generating a thrust FP1 in the direction of the push rod (900). The hydraulic oil P2 fed back from the load end generates a force FP2 on the front end surface of the compensator valve core (200). The force F+FP2 at the front end of the compensator valve core 200 is compared with the force FP1 at the rear end of the compensator valve core (200). When F+FP2<FP1, the compensator valve core (200) moves toward the push rod (900), the compensator valve port opening decreases, the pressure loss increases, the oil pressure in the P1 chamber decreases, and further causes FP1 to decrease until the forces at both ends of the compensator valve core (200) are balanced; When F+FP2=FP1, the forces at both ends of the compensator valve core (200) are balanced, and the compensator valve core (200) is stationary; When F+FP2>FP1, the compensator valve core (200) moves toward the oil inlet, the compensator valve port opening increases, the pressure loss decreases, and the oil pressure in the P1 chamber increases, further causing FP1 to increase until the forces at both ends of the compensator valve core are balanced.

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