Multi-stage flow control valve and hydraulic excavator equipped with the multi-stage flow control valve

Abstract

The present invention discloses a multi-stage flow regulating valve and a hydraulic excavator equipped with the multi-stage flow regulating valve. The multi-stage flow regulating valve comprises a regulating valve sleeve, the right end of which is connected to a regulating valve housing, and the right end of which is connected to a regulating valve back cover; the regulating valve sleeve and the regulating valve housing are installed in the valve core hole of the valve body; the regulating valve sleeve is equipped with a regulating valve core, the regulating valve housing is equipped with a spring seat, and the regulating valve back cover is equipped with a spring; the left end of the spring seat cooperates with the regulating valve core, and the right end of the spring seat contacts with the left end of the spring. The present invention effectively achieves the regulation of the pump port flow through the first-stage throttling, and effectively achieves the unloading of the pump port flow through the second-stage throttling, avoiding the risk of component damage and oil leakage caused by the pressure build-up at the P port due to mechanical failure or other problems in the hydraulic system.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control systems, in particular to a multi-stage flow regulating valve and a hydraulic excavator equipped with the multi-stage flow regulating valve. Background Art

[0002] With the rapid development of construction machinery, the quality and performance requirements of construction machinery parts are getting higher and higher. Especially in recent years, with the improvement of environmental awareness, higher requirements have been put forward for oil leakage and safety of construction machinery. The plate-type load-sensitive multi-way valves and load-sensitive pumps used in micro and small excavators are all subject to the load of the actuator, and their flow and pressure change with the load pressure. When the load pressure is out of control due to mechanical failure, it will cause the hydraulic system pressure and flow to be out of control. At this time, the hydraulic system unloading function will fail, and then the hydraulic pump or hydraulic valve function will fail, which will seriously lead to damage to the hydraulic pump and hydraulic valve parts and oil spray.

[0003] The Chinese patent discloses a relief valve and a combined valve type buffer oil cylinder (CN114439807A), which are used to achieve flow unloading and improve the safety of the system. The relief valve includes a valve body, a valve core and a return spring, and is also provided with a damping hole and a relief groove; the combined valve includes a relief valve and a throttle valve, and the throttle valve includes a buffer plug and a buffer chamber; the piston rod assembly of the combined valve type buffer oil cylinder is installed in the cylinder body, and the cylinder body includes a cylinder head flange, a cylinder bottom and a cylinder barrel, and the piston rod assembly includes a guide sleeve, a piston and a piston rod; the combined valve is arranged on the oil cylinder.

[0004] The disadvantages of the above technology are: the unloading valve has a single function, does not have a flow regulation function, has a low functional integration, and has a limited scope of use. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a multi-stage flow control valve and a hydraulic excavator equipped with the multi-stage flow control valve. The multi-stage flow control valve can adjust the system flow of the engineering machinery hydraulic excavator when it is working, and at the same time, avoid the risk of inter-plate leakage or oil spray caused by excessive pressure in the hydraulic system.

[0006] The present invention is achieved through the following technical solutions: a multi-stage flow control valve,

[0007] It comprises a regulating valve sleeve, the right end of which is connected to a regulating valve housing, and the right end of which is connected to a regulating valve back cover; the regulating valve sleeve and the regulating valve housing are installed in the valve core hole of the valve body; the regulating valve sleeve is matched with a regulating valve core, the regulating valve housing is matched with a spring seat, and the regulating valve back cover is equipped with a spring; the left end of the spring seat is matched with the regulating valve core, and the right end of the spring seat is in contact with the left end of the spring;

[0008] The valve body is provided with a Dr oil passage, a P oil passage, a T oil passage and an Ls oil passage;

[0009] The regulating valve sleeve is provided with a K oil passage opposite to the Dr oil passage, a Q oil passage opposite to the P oil passage, and an E oil passage opposite to the T oil passage;

[0010] The left end of the regulating valve core is the N cavity, which is connected to the L oil channel, the M oil channel and the K oil channel provided on the regulating valve sleeve; the outer surface of the middle part of the regulating valve core is provided with the F cavity which cooperates with the Q oil channel and the E oil channel; the outer surface of the regulating valve core on the left side of the F cavity is provided with the J cavity, which is connected to the F cavity, and the outer diameter of the regulating valve core on the left side of the J cavity is smaller than the outer diameter of the regulating valve core on the right side of the J cavity;

[0011] The regulating valve housing is provided with an A oil passage opposite to the Ls oil passage, the right end of the regulating valve core is a B chamber, and the A oil passage is in communication with the B chamber;

[0012] The left end of the spring seat and the right end of the regulating valve core are in clearance sliding fit, the axis of the spring seat is provided with a C oil channel, and the right end of the spring seat is a D volume cavity.

[0013] Further, the regulating valve sleeve is provided with a throttle hole I and a throttle hole II which are opposite to the T oil passage, the diameter of the throttle hole I is smaller than the diameter of the throttle hole II, and the throttle hole I is located on the left side of the throttle hole II.

[0014] The regulating valve core is provided with radial G oil passage and I oil passage, G oil passage is connected to F volume cavity, I oil passage is connected to J volume cavity; the left end of the regulating valve core is provided with H oil passage, H oil passage is connected to G oil passage and I oil passage, and a plug is installed at the left end of H oil passage.

[0015] The right end of the regulating valve core is provided with a shoulder, and the regulating valve core shoulder abuts against the right end of the regulating valve sleeve; the inner wall of the regulating valve housing is provided with a stopper, and the stopper is used to limit the displacement of the regulating valve core shoulder to the right.

[0016] The spring seat is provided with a shoulder, and the spring seat shoulder abuts against the right end of the stop platform of the regulating valve housing.

[0017] A wire retaining ring and an O-ring II are arranged between the left end of the regulating valve housing and the regulating valve sleeve, an O-ring I is arranged between the right end of the regulating valve housing and the regulating valve rear cover, and an O-ring III is arranged between the outer surface of the regulating valve housing and the valve core hole of the valve body.

[0018] An "O"-shaped sealing ring IV, an "O"-shaped sealing ring V and an "O"-shaped sealing ring VI are arranged between the outer surface of the valve sleeve of the regulating valve and the valve core hole of the valve body; the "O"-shaped sealing ring IV is located between the Q oil channel and the E oil channel; the "O"-shaped sealing ring V is located between the Dr oil channel and the Q oil channel; the "O"-shaped sealing ring VI is located on the left side of the Dr oil channel.

[0019] A hydraulic excavator adopts a multi-stage flow regulating valve.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] Make full use of the difference in the force on the valve core of the regulating flow valve, adjust the displacement difference between the valve core of the regulating flow valve and the valve sleeve of the regulating flow valve, and realize the regulation or unloading of the pump outlet flow; effectively realize the regulation of the pump port flow through the first-level throttling, and effectively realize the unloading of the pump port flow through the second-level throttling, avoiding the risk of component damage and oil leakage caused by the pressure of the P port due to mechanical failure or other problems in the hydraulic system;

[0022] The organic unity of flow regulation and system oil unloading is realized. The regulating valve has simple structure, powerful functions, compact structure and high integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the multi-stage flow control valve of the present invention;

[0024] Figure 2 It is a schematic diagram of the installation of the multi-stage flow control valve of the present invention;

[0025] Figure 3 yes Figure 2 An enlarged view of the left end of the valve core of the middle regulating valve;

[0026] Figure 4 It is a structural schematic diagram of the valve core of the regulating valve in the present invention;

[0027] Figure 5 It is a structural schematic diagram of the valve sleeve of the regulating valve in the present invention;

[0028] In the figure: regulating valve housing 1, spring seat 2, regulating valve back cover 3, "O"-shaped sealing ring Ⅰ4, spring 5, regulating valve sleeve 6, throttle hole Ⅰ6-1, throttle hole Ⅱ6-2, regulating valve core 7, wire retaining ring 8, "O"-shaped sealing ring Ⅱ9, "O"-shaped sealing ring III10, "O"-shaped sealing ring IV11, "O"-shaped sealing ring V12, "O"-shaped sealing ring VI13, plug 14. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0030] like Figures 1 to 3 As shown, a multi-stage flow control valve includes a control valve sleeve 6, the right end of the control valve sleeve 6 is connected to a control valve housing 1, and the right end of the control valve housing 1 is connected to a control valve back cover 3. The control valve sleeve 6 and the control valve housing 1 are installed in the valve core hole of the valve body. The control valve sleeve 6 is equipped with a control valve core 7, the control valve housing 1 is equipped with a spring seat 2, and the control valve back cover 3 is equipped with a spring 5. The left end of the spring seat 2 cooperates with the control valve core 7, and the right end of the spring seat 2 contacts the left end of the spring 5. The right end of the control valve core 7 has a shoulder, and the shoulder of the control valve core 7 abuts against the right end of the control valve sleeve 6; the inner wall of the control valve housing 1 has a stopper, which is used to limit the displacement of the shoulder of the control valve core 7 to the right. The spring seat 2 has a shoulder, and the shoulder of the spring seat 2 abuts against the right end of the stopper of the control valve housing 1.

[0031] A wire retaining ring 8 and an O-ring II 9 are arranged between the left end of the regulating valve housing 1 and the regulating valve sleeve 6, an O-ring I 4 is arranged between the right end of the regulating valve housing 1 and the regulating valve back cover 3, and an O-ring III 10 is arranged between the outer surface of the regulating valve housing 1 and the valve core hole of the valve body.

[0032] An "O"-shaped sealing ring IV11, an "O"-shaped sealing ring V12, and an "O"-shaped sealing ring VI13 are arranged between the outer surface of the regulating valve sleeve 6 and the valve core hole of the valve body. The "O"-shaped sealing ring IV11 is located between the Q oil passage and the E oil passage; the "O"-shaped sealing ring V12 is located between the Dr oil passage and the Q oil passage; and the "O"-shaped sealing ring VI13 is located on the left side of the Dr oil passage.

[0033] Combination Figures 2 to 5 As shown,

[0034] The valve body is provided with Dr oil passage, P oil passage, T oil passage and Ls oil passage;

[0035] The regulating valve sleeve 6 is provided with a K oil passage opposite to the Dr oil passage, a Q oil passage opposite to the P oil passage, and an E oil passage opposite to the T oil passage; the regulating valve sleeve 6 is provided with a throttle hole Ⅰ6-1 and a throttle hole Ⅱ6-2 opposite to the T oil passage, the diameter of the throttle hole Ⅰ6-1 is smaller than the diameter of the throttle hole Ⅱ6-2, and the throttle hole Ⅰ6-1 is located on the left side of the throttle hole Ⅱ6-2;

[0036] The left end of the regulating valve core 7 is the N cavity, which is connected to the L oil channel, M oil channel and K oil channel opened on the regulating valve sleeve 6; the outer surface of the middle part of the regulating valve core 7 is provided with an F cavity that cooperates with the Q oil channel and the E oil channel; the outer surface of the regulating valve core 7 on the left side of the F cavity is provided with a J cavity; the outer diameter of the regulating valve core 7 on the left side of the J cavity is smaller than the outer diameter of the regulating valve core 7 on the right side of the J cavity; the regulating valve core 7 is provided with radial G oil channels and I oil channels, the G oil channel is connected to the F cavity, and the I oil channel is connected to the J cavity; the left end of the regulating valve core 7 is provided with an H oil channel, the H oil channel is connected to the G oil channel and the I oil channel, and a plug 14 is installed at the left end of the H oil channel;

[0037] An A oil passage opposite to the Ls oil passage is opened on the regulating valve housing 1, the right end of the regulating valve core 7 is the B chamber, and the A oil passage is connected to the B chamber; the left end of the spring seat 2 and the right end of the regulating valve core 7 are in a clearance sliding fit, the axis of the spring seat 2 is opened with a C oil passage, and the right end of the spring seat 2 is the D chamber.

[0038] Working process:

[0039] The P oil channel is connected to the pump oil outlet, the Dr oil channel and the T oil channel are directly connected to the oil tank, and the load of each actuator is connected to the Ls oil channel through the maximum load selected by the shuttle valve network or the one-way valve logic oil circuit;

[0040] 1. When the actuators of the excavator are not working and the system is in an idle state, the pressure of each actuator is zero, that is, the pressure of the Ls oil circuit is zero;

[0041] At this time, the oil at the pump outlet passes through the P port → Q oil channel on the regulating valve sleeve 6 → F chamber → G oil channel on the regulating valve core 7 → H oil channel on the regulating valve core 7 → I oil channel on the regulating valve core 7 → J chamber; the structure of the regulating valve core 7 is shown in the figure. Figure 3 As shown, the regulating valve core 7 generates a rightward force under the action of the difference in cross-sectional area between X and Y and the pressure of the J chamber. At this time, the N chamber passes through the M oil passage on the regulating valve core 7 → the L oil passage on the regulating valve core 7 → the K oil passage on the regulating valve sleeve 6 → the Dr chamber;

[0042] In summary, when the force generated by the P port at the J chamber is greater than the spring force at the D chamber, the regulating valve core 7 moves to the right, and the movement of the regulating valve core 7 causes the P port to gradually communicate with the T port through the throttle hole Ⅰ6-1 of the regulating valve sleeve 6 (the structural diagram of the regulating valve sleeve 6 is shown in FIG. Figure 5 As shown in the figure), until the thrust generated by the P port at the J chamber and the spring force at the D chamber are stable, and the system is in the unloading state;

[0043] The movement of the regulating valve core 7 causes the oil in the oil tank to flow through the Dr oil channel → the K oil channel on the regulating valve sleeve 6 → the L oil channel on the regulating valve core 7 → the M oil channel on the regulating valve core 7 → the N volume chamber.

[0044] 2. When the excavator has an actuator working, the system is in working state.

[0045] At this time, the maximum load of the actuator is transmitted to the Ls oil channel through the shuttle valve network or the one-way valve logic oil circuit. The oil pressure of the Ls oil channel is transmitted through the A oil channel on the regulating valve housing 1 → the B volume chamber → the matching clearance between the spring seat 2 and the regulating valve core to the C oil channel on the spring seat 2 → the D volume chamber.

[0046] The flow direction of the pressure oil at port P is the same as the above idle state.

[0047] The oil flow state of the N chamber is the same as the above-mentioned idle state;

[0048] At this time, the force on the regulating valve core 7 is as follows:

[0049] The oil pressure at the P port, the spring force of the D chamber, and the pressure of the Ls oil circuit of the D chamber;

[0050] When the force generated by the pressure at the P port is less than or equal to the sum of the force generated by the spring force of the D volume chamber and the pressure of the Ls oil circuit of the D volume chamber, the regulating valve core 7 is in a closed state, that is, no system oil flows through the unloading valve to the T port;

[0051] When the force generated by the pressure at port P is greater than the sum of the forces generated by the spring force of the D chamber and the pressure of the oil circuit of the D chamber Ls, the regulating valve core 7 is in the open state, that is, part of the oil in the system charges the valve to port T, and the regulating valve is in the flow regulating state.

[0052] 3. When the hydraulic system fails,

[0053] State 1: The pump displacement is always affected by the Ls load pressure and continues to increase, causing the P port pressure to increase and exceed the system safety setting pressure;

[0054] State 2: The multi-way valve core is reset, but the Ls load pressure does not decay to zero with the reset of the valve core, but continues to exist, forming system pressure holding, and the system pressure exceeds the system safety setting pressure;

[0055] Under this working condition, the pressure at the P port continues to rise, and the regulating valve core 7 moves to the right in the J chamber (which is connected to the pressure at the P port) under the action of pressure. When the regulating valve core 7 moves to the L oil passage on the regulating valve core 7 and is connected to the J chamber (at this time, the L oil passage on the regulating valve core 7 and the K oil passage of the regulating valve sleeve 6 form a seal through the outer diameter of the regulating valve core 7 and the inner diameter of the regulating valve sleeve 6 and are not connected), the pressure oil discharged by the pump passes through a portion of the P port through the G oil passage on the regulating valve core 7 → the H oil passage on the regulating valve core 7. Oil channel → I oil channel on the regulating valve core 7 → J cavity → L oil channel on the regulating valve core 7 → M oil channel on the regulating valve core 7 → N cavity. The regulating valve core 7 moves right quickly under the pressure of the N cavity and the J cavity (the effective area is the Y section), so that the regulating valve core 7 is in a fully open state. At this time, the oil discharged by the pump completely passes through the P port → Q oil channel on the regulating valve sleeve 6 → F cavity → throttle hole Ⅰ6-1 and throttle hole Ⅱ6-2 on the regulating valve sleeve 6 to return to the oil tank, completing the full unloading of the hydraulic system;

[0056] In this case, the flow discharged from the pump port can be guaranteed to be completely unloaded, avoiding the impact and damage of changes in system pressure on other components. Example

[0057] A hydraulic excavator adopts the multi-stage flow regulating valve of the first embodiment.

[0058] The present invention solves the problem of leakage or even oil spray between main valve plates caused by excessive system pressure, and realizes the stability of hydraulic system pressure and rapid unloading of the system through multi-stage flow regulation. The first-stage regulation of the flow regulating valve can stabilize the pressure of the hydraulic system; the second-stage regulation of the flow regulating valve can unload the hydraulic system, avoiding the risk of pressure build-up in the hydraulic system and providing a guarantee for the safe operation of the hydraulic system.

[0059] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A multi-stage flow control valve, Features: The regulating valve comprises a regulating valve sleeve (6), the right end of the regulating valve sleeve (6) is connected to a regulating valve housing (1), and the right end of the regulating valve housing (1) is connected to a regulating valve back cover (3); the regulating valve sleeve (6) and the regulating valve housing (1) are installed in a valve core hole of a valve body; a regulating valve core (7) is installed in the regulating valve sleeve (6), a spring seat (2) is installed in the regulating valve housing (1), and a spring (5) is installed in the regulating valve back cover (3); the left end of the spring seat (2) is matched with the regulating valve core (7), and the right end of the spring seat (2) is in contact with the left end of the spring (5); The valve body is provided with a Dr oil passage, a P oil passage, a T oil passage and an Ls oil passage; The regulating valve sleeve (6) is provided with a K oil passage opposite to the Dr oil passage, a Q oil passage opposite to the P oil passage, and an E oil passage opposite to the T oil passage; The left end of the regulating valve core (7) is an N cavity, which is connected to the L oil passage, the M oil passage and the K oil passage provided on the regulating valve sleeve (6); the middle outer surface of the regulating valve core (7) is provided with an F cavity which cooperates with the Q oil passage and the E oil passage; the outer surface of the regulating valve core (7) on the left side of the F cavity is provided with a J cavity, which is connected to the F cavity, and the outer diameter of the regulating valve core (7) on the left side of the J cavity is smaller than the outer diameter of the regulating valve core (7) on the right side of the J cavity; The regulating valve housing (1) is provided with an A oil passage opposite to the Ls oil passage, the right end of the regulating valve core (7) is a B chamber, and the A oil passage is in communication with the B chamber; The left end of the spring seat (2) and the right end of the regulating valve core (7) are in clearance sliding fit, an oil passage C is provided at the axis of the spring seat (2), and the right end of the spring seat (2) is a cavity D.

2. A multi-stage flow control valve according to claim 1, characterized in that: The regulating valve sleeve (6) is provided with a throttle hole I (6-1) and a throttle hole II (6-2) opposite to the T oil passage, the diameter of the throttle hole I (6-1) is smaller than the diameter of the throttle hole II (6-2), and the throttle hole I (6-1) is located on the left side of the throttle hole II (6-2).

3. A multi-stage flow control valve according to claim 1, characterized in that: The regulating valve core (7) is provided with radial G oil passage and I oil passage, the G oil passage is connected to the F volume chamber, and the I oil passage is connected to the J volume chamber; the left end of the regulating valve core (7) is provided with an H oil passage, the H oil passage is connected to the G oil passage and the I oil passage, and a plug (14) is installed at the left end of the H oil passage.

4. A multi-stage flow control valve according to claim 1, characterized in that: The right end of the regulating valve core (7) is provided with a shoulder, and the shoulder of the regulating valve core (7) abuts against the right end of the regulating valve sleeve (6); the inner wall of the regulating valve housing (1) is provided with a stopper, and the stopper is used to limit the displacement of the shoulder of the regulating valve core (7) to the right.

5. A multi-stage flow control valve according to claim 4, characterized in that: The spring seat (2) has a shoulder, and the shoulder of the spring seat (2) abuts against the right end of the stopper of the regulating valve housing (1).

6. The multi-stage flow control valve according to claim 1, characterized in that: A wire retaining ring (8) and an O-ring II (9) are arranged between the left end of the regulating valve housing (1) and the regulating valve sleeve (6), an O-ring I (4) is arranged between the right end of the regulating valve housing (1) and the regulating valve rear cover (3), and an O-ring III (10) is arranged between the outer surface of the regulating valve housing (1) and the valve core hole of the valve body.

7. The multi-stage flow control valve according to claim 1, characterized in that: An O-ring IV (11), an O-ring V (12), and an O-ring VI (13) are arranged between the outer surface of the regulating valve sleeve (6) and the valve core hole of the valve body; the O-ring IV (11) is located between the Q oil passage and the E oil passage; the O-ring V (12) is located between the Dr oil passage and the Q oil passage; and the O-ring VI (13) is located on the left side of the Dr oil passage.

8. A hydraulic excavator, characterized in that: A multi-stage flow control valve according to any one of claims 1 to 7 is used.

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