Four-position valve rod assembly with pressure conduction deep hole and constant pressure reset structure

Abstract

The invention relates to a four-position valve rod assembly with a pressure conduction deep hole and a constant-pressure reset structure. The four-position valve rod assembly comprises an axial four-position valve rod arranged in a valve body and the pressure conduction deep hole integrated in the valve rod, and the inlet end of the pressure conduction deep hole communicates with a main oil way P opening; the positioning mechanism is a three-point mechanical locking assembly composed of a positioning sleeve, a steel ball, a positioning spring and a positioning push rod; the dynamic pressure compensation assembly comprises an adjustable pressure adjusting spring and a cone valve matched with the adjustable pressure adjusting spring; the impact unloading mechanism is composed of a positioning guide seat capable of axially sliding and a reset spring, and the positioning guide seat is provided with a stepped shaft damping structure; the pressure feedback oil way transmits the pressure of the main oil way to the pressure transmission deep hole of the valve rod through a one-way valve. Compared with a traditional external sensor scheme, the four-position valve rod assembly has the advantages that the response speed is greatly increased; the positioning mechanism realizes constant pressure and meets the application scene of continuous working of the executing mechanism; the quick reset pressure relief function of the executing mechanism is achieved through the impact unloading mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic multi-way directional control valves, and particularly to a four-position valve stem assembly with a pressure-conducting deep hole and a constant-pressure reset structure. Background Art

[0002] In a hydraulic multi-way directional control valve, there is such a working condition: when the multi-way valve switches to a certain working state, an actuator (such as a hydraulic cylinder) needs to work continuously, and when overloaded, it can be reset and unloaded in time to protect the hydraulic system, that is, the multi-way valve has a constant-pressure reset function.

[0003] The overload protection of traditional hydraulic multi-way directional control valves mostly relies on an electro-hydraulic control system composed of an external pressure sensor and an electromagnetic valve, which has problems such as response delay, complex structure, and low reliability. Existing mechanical overload protection mechanisms generally adopt a single spring reset structure, with low pressure control accuracy, and the reset impact is likely to cause positioning failure. Especially in the high-frequency impact working conditions of construction machinery, due to the long pressure signal transmission path (requiring external pipelines) and significant hydrodynamic interference of the traditional valve stem assembly, it is difficult to achieve precise constant-pressure unlocking, resulting in system unloading lag or malfunction.

[0004] In addition, in the prior art, the positioning mechanism and the pressure control mechanism are designed separately, resulting in redundant valve body structure, many leakage points, and insufficient wear resistance, and cannot meet the requirements of long-term stable operation of heavy equipment. Summary of the Invention

[0005] The purpose of the present invention is to provide a four-position valve stem assembly with a pressure-conducting deep hole and a constant-pressure reset structure, aiming to overcome the defects of the prior art and solve the problems such as response delay, complex structure, and low reliability of the electro-hydraulic control system composed of an external pressure sensor and an electromagnetic valve.

[0006] To this end, the present invention proposes a four-position valve stem assembly with a pressure-conducting deep hole and a constant-pressure reset structure, including:

[0007] An axially four-position valve stem arranged in the valve body, the valve stem having a neutral position, a left working position, a right working position, and a floating position;

[0008] A pressure-conducting deep hole integrated inside the valve stem, the inlet end of the pressure-conducting deep hole being communicated with the main oil circuit P port;

[0009] A positioning mechanism, a three-point mechanical locking assembly composed of a positioning sleeve, a steel ball, a positioning spring, and a positioning push rod;

[0010] A dynamic pressure compensation assembly, including an adjustable pressure regulating spring and a poppet valve cooperating therewith;

[0011] An impact unloading mechanism, composed of an axially slidable positioning guide seat and a reset spring, the positioning guide seat being provided with a stepped shaft damping structure;

[0012] The pressure feedback oil circuit conducts the main oil circuit pressure to the pressure conduction deep hole of the valve stem through a one-way valve.

[0013] As a preferred technical solution of the present application, a valve stem positioning hole for accommodating a steel ball is provided on the valve stem, and a positioning groove is provided on the positioning sleeve at the same time.

[0014] As a preferred technical solution of the present application, the steel ball in the positioning mechanism and the valve stem positioning hole are subjected to nitriding treatment, the surface hardness is ≥800HV, and an annular grease storage groove is provided at the bottom of the positioning groove.

[0015] As a preferred technical solution of the present application, the outlet end of the pressure conduction deep hole is communicated with the cone valve control cavity, its aperture is Φ2±0.05mm, and the L / D ratio is greater than 15.

[0016] As a preferred technical solution of the present application, the pre-tightening force adjustment range of the pressure regulating spring of the dynamic pressure compensation component is 13.5-20MPa.

[0017] As a preferred technical solution of the present application, the sealing surface angle of the cone valve is 60°±2°.

[0018] As a preferred technical solution of the present application, a pressure regulating mechanism is connected to the end of the valve stem, and the positioning guide seat for installing the pressure regulating spring is linked with the pressure regulating mechanism through a jump guide rod penetrating the positioning push rod; the pressure regulating mechanism includes a limit seat and a clamping screw arranged in sequence at the outer end of the jump guide rod, and also includes an end screw threadedly connected to the valve stem; the clamping screw is threadedly connected to the inner hole of the end screw, and the return spring is installed on the end screw through a spring mounting seat.

[0019] As a preferred technical solution of the present application, the pressure regulating mechanism further includes a set screw arranged at the outer end of the clamping screw, and the set screw is threadedly connected to the inner hole of the end screw.

[0020] The four-way valve stem assembly with a pressure conduction deep hole and a constant pressure reset structure provided by the present invention realizes the direct conduction of pressure signals through the axial deep hole of the valve stem. Compared with the traditional external sensor scheme, the response speed is greatly improved; by setting the positioning mechanism of the three-point mechanical locking assembly, constant pressure is realized to meet the application scenario of the continuous operation of the actuator; by setting the impact unloading mechanism composed of a cone valve and a positioning guide seat, the function of rapid reset and pressure relief of the actuator is satisfied.

[0021] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The following will refer to the drawings to make a further detailed description of the present application. Brief Description of the Drawings

[0022] The accompanying drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0023] Figure 1 is a schematic structural diagram of a four-position valve stem assembly with a pressure-conducting deep hole and a constant-pressure reset structure according to the present invention;

[0024] Figure 2 is a schematic structural diagram of a hydraulic multi-way directional control valve in the neutral state according to the present invention;

[0025] Figure 3 is a schematic structural diagram of a hydraulic multi-way directional control valve in the commutated state according to the present invention;

[0026] Explanation of reference numerals: 1, valve stem; 2, poppet valve; 3, pressure-regulating spring; 4, positioning guide seat; 5, skip-position guide rod; 6, positioning sleeve; 7, steel ball; 8, positioning spring; 9, positioning push rod; 10, pressure-conducting deep hole; 11, limit seat; 12, return spring; 13, clamping screw; 14, set screw; 15, end screw. Detailed Description of the Invention

[0027] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The following will refer to the drawings and combine with the embodiments to detail this application.

[0028] As Figures 1 to 3 shown, the four-position valve stem assembly with a pressure-conducting deep hole and a constant-pressure reset structure according to the present invention mainly includes: a valve stem 1, a positioning mechanism, a dynamic pressure compensation assembly, an impact unloading mechanism, and a pressure feedback oil circuit.

[0029] Among them, an axially four-position valve stem 1 is arranged in the valve body, and the valve stem has a neutral position, a left working position, a right working position, and a floating position; a pressure-conducting deep hole 10 is arranged inside the valve stem, and the L / D ratio of the deep hole is greater than 15, and its inlet end is communicated with the main oil circuit P port; the positioning mechanism is a three-point mechanical locking assembly composed of a positioning sleeve 6, a steel ball 7, a positioning spring 8, and a positioning push rod 9.

[0030] The dynamic pressure compensation assembly includes an adjustable pressure-regulating spring 3 and an inverted conical poppet valve 2 cooperating with it; the impact unloading mechanism is composed of an axially slidable positioning guide seat 4 and a return spring 12, and the positioning guide seat 4 is provided with a stepped shaft damping structure; the pressure feedback oil circuit conducts the main oil circuit pressure to the pressure-conducting deep hole 10 of the valve stem through a check valve.

[0031] Specifically, as Figure 1As shown, a positioning hole for accommodating a steel ball 7 is provided on the valve stem 1, and a positioning groove is provided on the positioning sleeve 6; the steel ball 7 moves with the valve stem 1 to the positioning groove and slides into the positioning groove under the extrusion of the positioning push rod 9 with a conical surface, realizing the axial positioning of the valve stem 1, so that the multi-way directional control valve can continuously work at the working position for a long time and maintain a stable state without the need to continuously provide thrust, realizing the positioning function. Among them, the steel ball 7 and the valve stem positioning hole are nitrided, the surface hardness is ≥800HV, and an annular grease storage groove is provided at the bottom of the positioning groove.

[0032] As Figure 1 shown, a pressure regulating mechanism is connected to the end of the valve stem 1. The positioning guide seat 4 for installing the pressure regulating spring 3 is linked with the pressure regulating mechanism through the skip-position guide rod 5 penetrating the positioning push rod 9. Among them, the pressure regulating mechanism includes a limit seat 11, a clamping screw 13, and a set screw 14 arranged in sequence at the outer end of the skip-position guide rod 5, and the clamping screw 13 and the set screw 14 are threadedly connected to the inner hole of the end screw 15. The return spring 12 is installed on the end screw 15 through a spring mounting seat, and at the same time, the end screw 15 is threadedly connected to the valve stem 1; by using an internal hexagon wrench to screw the clamping screw 13, the positions of the limit seat 11 and the positioning guide seat 4 at the other end of the skip-position guide rod 5 are adjusted, thereby adjusting the pre-compression amount of the pressure regulating spring 3, setting the return pressure of the valve stem 1, and then locking and positioning through the set screw 14. Among them, the pre-tightening force adjustment range of the pressure regulating spring 3 is 13.5 - 20 MPa.

[0033] In this embodiment, the outlet end of the pressure conduction deep hole 10 is communicated with the control cavity of the poppet valve 2, its aperture is Φ2 ± 0.05 mm, and the L / D ratio is greater than 15; preferably, the depth-diameter ratio L / D of the pressure conduction deep hole 10 is 18:1; realizing the direct conduction of the pressure signal, compared with the traditional external sensor scheme, the response speed is greatly improved. The sealing surface angle of the poppet valve 2 is 60° ± 2°, and a suitable sealing surface size can ensure high stability in the non-opening state of the dynamic pressure compensation component, avoiding positioning failure easily caused by the reset impact

[0034] As Figure 3 shown, when the multi-way valve is commutated, the positioning mechanism composed of the positioning sleeve 6, the steel ball 7, the positioning spring 8, the positioning push rod 9, etc. overcomes the elastic force of the return spring 12 to lock the valve stem in this working state. At this time, the pressure oil from the oil inlet connection of the multi-way valve is divided into two paths, one path is through P - B - actuator - A - T, and the other path is connected to the valve stem pressure sensing port through a check valve.

[0035] As Figure 2 shown, the pressure regulating spring 3 can set the valve stem return pressure. When the load pressure reaches the pressure set by the pressure regulating spring, the poppet valve 2 opens, the positioning guide seat 4 quickly moves under the action of the oil pressure and impacts the positioning push rod 9, the steel ball 7 moves out of the positioning groove, and under the action of the elastic force of the return spring 12, the valve stem returns toFigure 2 The reset state shown, at this time, the pressure oil port P is directly connected to the oil return port T, and the system is unloaded.

[0036] The working principle and process of the four-position valve stem assembly with a pressure-conducting deep hole and a constant-pressure reset structure of the present invention are briefly described below.

[0037] I. Structural characteristics and functional positioning of the four-position valve stem assembly of the present invention

[0038] The valve stem assembly adopts a four-position design (neutral position, left working position, right working position, floating position), and internally integrates a pressure-conducting deep hole and a two-stage pressure control mechanism. The core features are as follows:

[0039] 1. Positioning mechanism: A three-point mechanical locking structure composed of a positioning sleeve 6, a steel ball 7, a positioning spring 8, and a positioning push rod 9;

[0040] 2. Pressure sensing system: A closed-loop feedback oil circuit formed by the valve stem pressure sensing port and a check valve;

[0041] 3. Double-spring pressure regulating system: The pressure regulating spring 3 and the reset spring 12 form a dynamic pressure balance system;

[0042] 4. Impact unloading mechanism: A high-speed response impact mechanism composed of a poppet valve 2 and a positioning guide seat 4.

[0043] II. Detailed explanation of the working process of the four-position valve stem assembly of the present invention

[0044] (I) Normal commutation and locking stage

[0045] 1. When the operator switches the valve stem to the working position, the positioning push rod 9 compresses the reset spring 12 with the help of hydraulic assistance;

[0046] 2. The steel ball 7 is embedded in the valve stem positioning groove under the action of the positioning spring 8 to form a mechanical interlock;

[0047] 3. The main oil circuit is formed: Main working oil circuit: P→B→actuator→A→T; Pressure feedback oil circuit: P→check valve→pressure sensing cavity;

[0048] 4. At this time, the pressure regulating spring 3 is in a pre-compressed state, and the poppet valve 2 remains closed.

[0049] (II) Overload protection trigger stage

[0050] 1. When the load pressure PL≥the set value Ps of the pressure regulating spring 3: PL·A cone surface>F spring 3→the poppet valve 2 opens (A is the effective acting area of the poppet valve);

[0051] 2. The pressure oil enters the back cavity of the positioning guide seat 4 through the poppet valve pressure relief hole;

[0052] 3. The positioning guide base 4 generates an axial displacement under the action of hydraulic thrust;

[0053] 4. The impact surface of the guide base impacts the positioning push rod 9 with kinetic energy E = 1 / 2mv 2 to generate a mechanical unlocking pulse.

[0054] (III) Quick reset stage

[0055] 1. The impact energy causes the steel ball 7 to overcome the holding force of the positioning spring 8 and disengage from the positioning groove;

[0056] 2. The elastic potential energy stored in the reset spring 12 is instantaneously released;

[0057] 3. The valve stem moves towards the middle position with an acceleration a = (F spring 12 - F friction) / m rod under the drive of the spring force;

[0058] 4. The main oil circuit is switched to the P→T direct connection state, and the system is unloaded.

[0059] III. Innovative design highlights of the four-position valve stem assembly of the present invention

[0060] 1. Built-in pressure sensing: The pressure signal is directly transmitted through the axial deep hole of the valve stem (L / D > 15). Compared with the traditional external sensor scheme, the response speed is increased by 40%;

[0061] 2. Double damping structure: The stepped shaft structure of the positioning guide base 4 cooperates with the end face throttle groove to form a two-stage damping system, effectively suppressing pressure shock;

[0062] 3. Wear-resistant design: The steel ball 7 and the positioning groove are nitrided (surface hardness ≥ 800HV), combined with the design of the grease storage groove, so that the service life of the mechanism reaches more than 500,000 times.

[0063] IV. Typical application scenarios of the four-position valve stem assembly of the present invention

[0064] This structure is particularly suitable for construction machinery with periodic impact loads, such as: 1. The boom hydraulic system of excavators: preventing sudden impact loads during excavation operations; 2. The hoisting mechanism of cranes: coping with the negative load conditions caused by the sudden release of heavy objects; 3. The hydraulic breaker system: handling the rapid unloading requirements of high-frequency impact loads; 4. The propulsion system of shield machines: adapting to the pressure fluctuations caused by sudden changes in the formation.

[0065] Through the integrated pressure detection and mechanical actuator, this design realizes the essential safety upgrade on the basis of the traditional multi-way valve. The system reliability index (MTBF) is increased from 2000 hours to more than 5000 hours, and at the same time, 30% of the external control components are reduced, with significant technical and economic advantages.

[0066] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and variations can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A hydraulic multi-way reversing valve stem assembly with a constant pressure reset structure, characterized in that: include: An axial four-position valve stem (1) is arranged in the valve body, and the valve stem (1) has a middle position, a left working position, a right working position and a floating position; A pressure conduction deep hole (10) integrated inside the valve stem, wherein the inlet end of the pressure conduction deep hole (10) is connected to the main oil circuit P port; The positioning mechanism is a three-point mechanical locking assembly consisting of a positioning sleeve (6), a steel ball (7), a positioning spring (8) and a positioning push rod (9); A dynamic pressure compensation component, comprising an adjustable pressure regulating spring (3) and a cone valve (2) matched therewith; The impact unloading mechanism is composed of an axially slidable positioning guide seat (4) and a return spring (12), wherein the positioning guide seat (4) is provided with a stepped shaft damping structure; The pressure feedback oil circuit transmits the main oil circuit pressure to the pressure transmission deep hole (10) of the valve stem through the one-way valve.

2. The valve stem assembly according to claim 1, characterized in that: The valve stem (1) is provided with a valve stem positioning hole for accommodating a steel ball (7), and the positioning sleeve (6) is provided with a positioning groove.

3. The valve stem assembly according to claim 2, characterized in that: The steel ball (7) and the valve stem positioning hole in the positioning mechanism are nitrided, with a surface hardness of ≥800HV, and an annular grease storage groove is provided at the bottom of the positioning groove.

4. The valve stem assembly according to claim 1, characterized in that: The outlet end of the pressure conduction deep hole (10) is communicated with the control chamber of the cone valve (2), the hole diameter is Φ2±0.05 mm, and the L / D ratio is greater than 15.

5. The valve stem assembly according to claim 1, characterized in that: The preload force adjustment range of the pressure regulating spring (3) of the dynamic pressure compensation component is 13.5-20 MPa.

6. The valve stem assembly according to claim 1, characterized in that: The sealing surface angle of the cone valve (2) is 60°±2°.

7. The valve stem assembly according to claim 1, characterized in that: The end of the valve stem (1) is connected to a pressure regulating mechanism, and a positioning guide seat (4) on which a pressure regulating spring (3) is installed is linked to the pressure regulating mechanism via a jump guide rod (5) that penetrates a positioning push rod (9); The pressure regulating mechanism comprises a limit seat (11) and a tightening screw (13) arranged in sequence at the outer end of the jump guide rod (5), and also comprises an end screw (15) threadedly connected to the valve stem (1); the tightening screw (13) is threadedly connected to the inner hole of the end screw (15), and the return spring (12) is installed on the end screw (15) through a spring mounting seat.

8. The valve stem assembly according to claim 7, characterized in that: The pressure regulating mechanism further comprises a set screw (14) arranged at the outer end of the tightening screw (13), and the set screw (14) is threadedly connected to the inner hole of the end screw (15).

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