A control structure of a hydraulic directional control valve

Abstract

The present invention belongs to the technical field of hydraulic directional control valves, and particularly relates to a control structure of a hydraulic directional control valve. The control structure includes Control Component I and Control Component II, which are respectively located on both sides of the valve body; the Control Component I includes an end cover, a buffer spool, Check Valve I and Check Valve II; holes I and II are provided inside the end cover; a first working oil port and a second working oil port that are both communicated with hole I are provided on the end cover, and a fourth working oil port, a fifth working oil port, a sixth working oil port and a seventh working oil port that are both communicated with hole II are provided on the end cover; the fourth working oil port is further communicated with the sixth working oil port via hole II and the first buffer spool throttle groove, and the fifth working oil port is further communicated with the seventh working oil port via hole II and the second buffer spool throttle groove. The present invention can not only reduce hydraulic shock but also does not affect the spool opening response of the hydraulic control directional valve, and will not excessively reduce the spool reset speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic directional control valves, and particularly relates to a control structure of a hydraulic directional control valve. Background Art

[0002] At present, when the working device of a mobile machine is operating, a hydraulic directional control valve is commonly used to control the movement of its hydraulic mechanism. The control performance of the hydraulic directional control valve plays a key role in the operating performance, efficiency, and fuel consumption of the working device.

[0003] The commutation of the hydraulic directional control valve controls the movement speed and direction of the working device. However, if the commutation speed of the hydraulic directional control valve is too fast, it will cause a sharp change in the liquid flow speed and direction, resulting in hydraulic shock. The impact pressure value may reach several times or more of the system working pressure. Excessive impact will not only affect the discomfort of the operator but also often cause vibration, damage to instruments, and even lead to pipeline rupture.

[0004] Taking an excavator as an example, the working mechanism of the excavator is controlled by a hydraulic directional control valve. The commutation of the hydraulic directional control valve is controlled by a pilot handle. When the operator stops a certain action, the pilot handle is often directly released. The rapid return of the handle will cause the spool of the hydraulic directional control valve to quickly reset, resulting in shock. The following several methods are often used for the pilot-operated directional control valve to reduce shock:

[0005] 1. Add a one-way throttle valve to the pilot end of the spool of the hydraulic directional control valve, as shown in Figure 1 Taking the operation of the left pilot handle and the left side of the hydraulic directional control valve being connected to the pilot oil and the spool moving to the right as an example, the pilot oil enters the left pilot end of the pilot-operated directional control valve through the left one-way valve and the left throttle valve. At the same time, the hydraulic oil in the right pilot end of the pilot-operated directional control valve can only return to the fuel tank through the right throttle valve. Although this design is beneficial for fine operation, when rapid action is required, the responsiveness of the spool of the hydraulic directional control valve is poor, increasing the commutation time.

[0006] When the left pilot handle is released, the hydraulic oil in the left pilot end of the hydraulic directional control valve is affected by the left throttle valve, and the reset speed is reduced, thereby reducing the shock. However, in the whole process of the spool of the pilot-operated directional control valve resetting, it will be affected by the left throttle valve. When the oil temperature is relatively low, it will greatly increase the reset time of the spool of the pilot-operated directional control valve, resulting in the situation that the working device is still moving after the operator releases the left pilot handle. This situation often occurs and is extremely likely to cause accidents.

[0007] 2. Add a buffer valve to control the commutation of the hydraulic directional control valve, as shown in Figure 2As shown in the figure. Taking the operation of the left pilot handle and the movement of the spool of the hydraulically controlled directional valve to the right when the left side is connected to the pilot oil as an example, the pilot oil passes through A1, acts on the left pilot end of the hydraulically controlled directional valve through the left check valve and the left throttle valve, and at the same time, the pilot oil acts on the left control end of the buffer valve to make the buffer valve in the left working position. The hydraulic oil in the right pilot end of the hydraulic directional valve returns oil through the right throttle valve and the left working position of the buffer valve, enabling the spool of the hydraulic directional valve to move quickly. This design solves the response problem when the spool of the hydraulic directional valve is opened.

[0008] When the left pilot handle is released, the buffer valve quickly returns to the middle position. The hydraulic oil in the left pilot end of the hydraulically controlled directional valve is still affected by the left throttle valve, reducing the reset speed of the hydraulically controlled directional valve and thus reducing the impact. Similarly, this design causes the entire process of the hydraulically controlled directional valve's reset to be affected by the left throttle valve. When the oil temperature is relatively low, it will greatly increase the reset time of the hydraulically controlled directional valve, resulting in the situation where the working device is still moving after the operator releases the left pilot handle. This situation occurs frequently and is extremely likely to cause accidents. Summary of the Invention

[0009] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a control structure for a hydraulic directional valve, which can not only reduce hydraulic shock but also does not affect the opening response of the spool of the hydraulically controlled directional valve and will not overly reduce the spool reset speed.

[0010] The present invention is realized through the following technical solutions: A control structure for a hydraulic directional valve, which includes Control Component Ⅰ and Control Component Ⅱ. Control Component Ⅰ and Control Component Ⅱ are respectively located on both sides of the valve body;

[0011] The Control Component Ⅰ includes an end cover, a buffer spool, Check Valve Ⅰ and Check Valve Ⅱ; there are Hole Ⅰ and Hole Ⅱ in the end cover; the end cover is provided with a first working oil port and a second working oil port both communicating with Hole Ⅰ, and the end cover is provided with a fourth working oil port, a fifth working oil port, a sixth working oil port and a seventh working oil port all communicating with Hole Ⅱ;

[0012] The Check Valve Ⅰ is arranged between the fourth working oil port and the sixth working oil port, and the Check Valve Ⅰ conducts unidirectionally from the fourth working oil port to the sixth working oil port. The Check Valve Ⅱ is arranged between the fifth working oil port and the seventh working oil port, and the Check Valve Ⅱ conducts unidirectionally from the fifth working oil port to the seventh working oil port;

[0013] The fourth working oil port is also communicated with the sixth working oil port through Hole Ⅱ and the first buffer spool throttle groove. The fifth working oil port is also communicated with the seventh working oil port through Hole Ⅱ and the second buffer spool throttle groove;

[0014] The main spool of the valve body extends into Hole Ⅰ. The Control Component Ⅰ is provided with a hydraulic control chamber Ⅰ for controlling the main spool. The second working oil port is respectively communicated with the hydraulic control chamber Ⅰ and the sixth working oil port;

[0015] The buffer spool valve is placed inside the hole II. The control assembly I is provided with a spring control chamber I and a pilot chamber that are both used to control the buffer spool valve. The spring control chamber I and the pilot chamber are respectively located on both sides of the buffer spool valve. The buffer spool valve is axially provided with a fifth oil passage connecting the spring control chamber I and the pilot chamber. A fixed liquid resistance is provided inside the fifth oil passage. An oil discharge port communicating with the spring control chamber I is provided on the end cover;

[0016] The control assembly II includes a valve rod connected to the main spool valve of the valve body. The control assembly II includes a spring control chamber II and a hydraulic control chamber II that are both used to control the valve rod. The spring control chamber II and the hydraulic control chamber II are respectively located on both sides of the valve rod; The control assembly II is provided with a third working oil port communicating with the hydraulic control chamber II, and the third working oil port is also communicated with the seventh working oil port;

[0017] When the control structure is in the initial position state, the first working oil port and the pilot chamber of the control assembly I are in a cut-off state;

[0018] When the control structure is in the working position state, the first working oil port is communicated with the pilot chamber of the control assembly I via the hole I and the main spool valve throttle groove.

[0019] In some embodiments, the hole I is provided with a first oil passage, a second oil passage, and a third oil passage. The first oil passage is located between the second oil passage and the third oil passage, and the first oil passage is communicated with the first working oil port; The main spool valve throttle groove includes a first main spool valve throttle groove and a second main spool valve throttle groove. The first main spool valve throttle groove and the second main spool valve throttle groove are both communicated with the first oil passage, and the first main spool valve throttle groove is arranged on the side close to the second oil passage, and the second main spool valve throttle groove is arranged on the side close to the third oil passage;

[0020] The hole II is successively provided with a sixth oil passage, a seventh oil passage, an eighth oil passage, and a ninth oil passage. The sixth oil passage is communicated with the fourth working oil port, the seventh oil passage is communicated with the sixth working oil port, the eighth oil passage is communicated with the seventh working oil port, and the ninth oil passage is communicated with the fifth working oil port; The first buffer spool valve throttle groove is respectively communicated with the sixth oil passage and the seventh oil passage, and the second buffer spool valve throttle groove is respectively communicated with the eighth oil passage and the ninth oil passage;

[0021] It further includes a fourth oil passage. One end of the fourth oil passage is connected to the pilot chamber of the control assembly I, and the other end of the fourth oil passage is respectively connected to the second oil passage and the third oil passage.

[0022] In some embodiments, the flow area of the throttling groove of the first main spool gradually decreases from the first oil passage side to the second oil passage side; the flow area of the throttling groove of the second main spool gradually decreases from the first oil passage side to the third oil passage side; the flow area of the throttling groove of the first buffer spool gradually decreases from the sixth oil passage side to the seventh oil passage side; the flow area of the throttling groove of the second buffer spool gradually decreases from the eighth oil passage side to the ninth oil passage side.

[0023] In some embodiments, when the main spool of the valve body is in the neutral position, the throttling groove of the first main spool is in a cut-off state with the second oil passage, and the throttling groove of the second main spool is in a cut-off state with the third oil passage;

[0024] When the main spool of the valve body is in the left working position, the throttling groove of the first main spool is communicated with the second oil passage, and the throttling groove of the second main spool is in a cut-off state with the third oil passage;

[0025] When the main spool of the valve body is in the right working position, the throttling groove of the first main spool is in a cut-off state with the second oil passage, and the throttling groove of the second main spool is in a conducting state with the third oil passage.

[0026] In some embodiments, the control assembly II includes a spring end cover, a spring seat I, a spring seat II and a spring; the valve rod is placed in the inner cavity of the spring end cover, both the spring seat I and the spring seat II are sleeved on the valve rod, the spring is arranged between the spring seat I and the spring seat II, one end of the spring seat I away from the spring is limited by the valve body, and one end of the spring seat II away from the spring is limited by the valve rod.

[0027] In some embodiments, the one-way valve I includes a mounting seat I and a piston I. The piston I is provided with an axial through hole I. A spring I is arranged between the mounting seat I and the piston I. An axial hole I is provided for communication between the fourth working oil port and the sixth working oil port; the one-way valve I is axially mounted on the end cover through the mounting seat I. Initially, under the action of the spring I, the side of the piston I away from the spring I passes through the fourth working oil port and abuts against the orifice of the axial hole I, so that the fourth working oil port and the axial hole I are in a cut-off state.

[0028] In some embodiments, the one-way valve II includes a mounting seat II and a piston II. The piston II is provided with an axial through hole II. A spring II is arranged between the mounting seat II and the piston II. An axial hole II is provided for communication between the fifth working oil port and the seventh working oil port; the one-way valve II is axially mounted on the end cover through the mounting seat II. Initially, under the action of the spring II, the side of the piston II away from the spring II passes through the fifth working oil port and abuts against the orifice of the axial hole II, so that the fifth working oil port and the axial hole II are in a cut-off state.

[0029] The beneficial effects of the present invention are as follows: The present invention can not only reduce hydraulic shock but also does not affect the spool opening response of the hydraulic control directional valve, and will not excessively reduce the spool reset speed. In addition, different control effects can be obtained by changing the throttle groove shapes on the main spool and the buffer spool and changing the fixed liquid resistance specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a hydraulic control schematic diagram of the prior art I;

[0031] Figure 2 is a hydraulic control schematic diagram of the prior art II;

[0032] Figure 3 is a structural schematic diagram of the hydraulic control directional valve of the present invention;

[0033] Figure 4 is a structural schematic diagram of the control component I of the present invention;

[0034] Figure 5 is a hydraulic control schematic diagram of the control structure of the present invention;

[0035] Figure 6 is a schematic diagram of the C-type hydraulic half-bridge formed by the present invention;

[0036] In the figure, 1. Control component I, 1-1. End cover, 1-11. Hole I, 1-12. Hole II, 1-2. Buffer spool, 1-3. Buffer spool mounting seat, 1-4. Check valve I, 1-41. Mounting seat I, 1-42. Piston I, 1-5. Check valve II, 1-51. Mounting seat II, 1-52. Piston II, 1-6. Fixed liquid resistance, 1-7. Axial hole I, 1-8. Axial hole II, 2. Valve body, 2-1. Main spool, 3. Control component II, 3-1. Spring end cover, 3-2. Valve stem, 3-3. Spring seat I, 3-4. Spring seat II, 3-5. Spring. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be further described below with reference to the drawings and embodiments.

[0038] As Figure 3 and Figure 4 shown, a control structure of a hydraulic directional valve, the control structure includes a control component I 1 and a control component II 3, the control component I 1 and the control component II 3 are respectively located on both sides of the valve body 2, and the main spool 2-1 of the valve body 2 is controlled to change direction by the combined action of the control component I 1 and the control component II 3.

[0039] Specifically, as Figure 3 and Figure 4As shown, the control component Ⅰ1 includes an end cap 1-1, a buffer spool 1-2, a check valve Ⅰ1-4, and a check valve Ⅱ1-5. A hole Ⅰ1-11 and a hole Ⅱ1-12 are provided inside the end cap 1-1; the main spool 2-1 of the valve body 2 extends into the hole Ⅰ1-11, the right side of the main spool 2-1 is connected to the control component Ⅱ3, and a hydraulic control cavity Ⅰ for controlling the main spool 2-1 is formed between the left side of the main spool 2-1 and the end cap 1-1. The buffer spool 1-2 is installed in the hole Ⅱ1-12, a spring control cavity Ⅰ Y11 is formed between the right side of the buffer spool 1-2 and the end cap 1-1, an oil drain port communicating with the spring control cavity Ⅰ Y11 is provided on the end cap 1-1, a spring for controlling the buffer spool 1-2 is arranged in the spring control cavity Ⅰ Y11, a buffer spool mounting seat 1-3 is threadedly connected to the end cap 1-1, and a pilot cavity Y5 is designed between the left side of the buffer spool 1-2 and the buffer spool mounting seat 1-3. The buffer spool 1-2 is axially provided with a fifth oil passage Y6 connecting the spring control cavity Ⅰ Y11 and the pilot cavity Y5, and a fixed liquid resistance 1-6 is arranged in the fifth oil passage Y6.

[0040] As Figure 3 and Figure 4 shown, a first oil passage Y1, a second oil passage Y2, and a third oil passage Y3 are provided on the hole Ⅰ1-11, and the first oil passage Y1 is located between the second oil passage Y2 and the third oil passage Y3. The main spool 2-1 is provided with a first main spool throttle groove a and a second main spool throttle groove b, both the first main spool throttle groove a and the second main spool throttle groove b communicate with the first oil passage Y1, and the first main spool throttle groove a is arranged closer to the second oil passage Y2 side, and the second main spool throttle groove b is arranged closer to the third oil passage Y3 side. When the main spool 2-1 of the valve body 2 is in the middle position, the first main spool throttle groove a is in a cut-off state with the second oil passage Y2, and the second main spool throttle groove b is in a cut-off state with the third oil passage Y3. When the main spool 2-1 of the valve body 2 is in the left working position (as Figure 3 and Figure 4 shown, the main spool 2-1 moves towards the right side), the first main spool throttle groove a communicates with the second oil passage Y2, and the second main spool throttle groove b is in a cut-off state with the third oil passage Y3. When the main spool 2-1 of the valve body 2 is in the right working position (as Figure 3 and Figure 4 shown, the main spool 2-1 moves towards the left side), the first main spool throttle groove a is in a cut-off state with the second oil passage Y2, and the second main spool throttle groove b communicates with the third oil passage Y3. Specifically, the flow area of the first main spool throttle groove a gradually decreases from the first oil passage Y1 side towards the second oil passage Y2 side; the flow area of the second main spool throttle groove b gradually decreases from the first oil passage Y1 side towards the third oil passage Y3 side.

[0041] As Figure 3 and Figure 4As shown, a sixth oil passage Y7, a seventh oil passage Y8, an eighth oil passage Y9, and a ninth oil passage Y10 are successively provided on the hole II 1-12. A first buffer valve core throttle groove c and a second buffer valve core throttle groove d are provided on the buffer valve core 1-2. The first buffer valve core throttle groove c connects the sixth oil passage Y7 and the seventh oil passage Y8; the flow-through area of the first buffer valve core throttle groove gradually decreases from the sixth oil passage Y7 side to the seventh oil passage Y8 side. The sixth oil passage Y7 and the seventh oil passage Y8 are always kept in a connected state through the first buffer valve core throttle groove c. The second buffer valve core throttle groove d connects the eighth oil passage Y9 and the ninth oil passage Y10; the flow-through area of the second buffer valve core throttle groove gradually decreases from the eighth oil passage Y9 side to the ninth oil passage Y10 side. The eighth oil passage Y9 and the ninth oil passage Y10 are always kept in a connected state through the second buffer valve core throttle groove d.

[0042] As Figure 3 and Figure 4 shown, a first working oil port X0 and a second working oil port X1 that are both connected to the hole I 1-11 are provided on the end cover 1-1, and a fourth working oil port X3, a fifth working oil port X4, a sixth working oil port X5, and a seventh working oil port X6 that are both connected to the hole II 1-12 are provided on the end cover 1-1. Specifically, the first working oil port X0 is connected to the first oil passage Y1, the second working oil port X1 is connected to the hydraulic control cavity I of the control component I 1, and the second working oil port X1 is also connected to the sixth working oil port X5 through an external pipeline. The fourth working oil port X3 is connected to the sixth oil passage Y7, the sixth working oil port X5 is connected to the seventh oil passage Y8, the seventh working oil port X6 is connected to the eighth oil passage Y9, and the fifth working oil port X4 is connected to the ninth oil passage Y10. As can be seen from the foregoing, the fourth working oil port X3, the sixth oil passage Y7, the seventh oil passage Y8, and the sixth working oil port X5 form a two-way conduction oil passage through the first buffer valve core throttle groove c; the fifth working oil port X4, the ninth oil passage Y10, the eighth oil passage Y9, and the seventh working oil port X6 form a two-way conduction oil passage through the second buffer valve core throttle groove d.

[0043] A one-way conduction oil passage is also provided between the fourth working oil port X3 and the sixth working oil port X5 and between the fifth working oil port X4 and the seventh working oil port X6. Specifically, as Figure 3 and Figure 4As shown in the figure, an axial hole Ⅰ 1-7 communicating the fourth working oil port X3 and the sixth working oil port X5 is further axially provided on the end cover 1-1. The check valve Ⅰ 1-4 is installed on the end cover 1-1 and acts on the axial hole Ⅰ 1-7 to form an oil passage channel that conducts unidirectionally from the fourth working oil port X3 to the sixth working oil port X5. An axial hole Ⅱ 1-8 communicating the fifth working oil port X4 and the seventh working oil port X6 is further axially provided on the end cover 1-1. The check valve Ⅱ 1-5 is installed on the end cover 1-1 and acts on the axial hole Ⅱ 1-8 to form an oil passage channel that conducts unidirectionally from the fifth working oil port X4 to the seventh working oil port X6.

[0044] As Figure 3 and Figure 4 shown in the figure, a fourth oil passage Y4 is further provided on the end cover 1-1. One end of the fourth oil passage Y4 is connected to the pilot chamber Y5 of the control component Ⅰ 1, and the other end of the fourth oil passage Y4 is respectively connected to the second oil passage Y2 and the third oil passage Y3.

[0045] As Figure 3 and Figure 4 shown in the figure, the control component Ⅱ 3 includes a spring end cover 3-1, a valve rod 3-2, a spring seat Ⅰ 3-3, a spring seat Ⅱ 3-4, and a spring 3-5. The valve rod 3-2 is placed in the inner cavity of the spring end cover 3-1. The valve rod 3-2 is threadedly connected to the main spool 2-1 of the valve body 2. The side of the valve rod 3-2 close to the main spool 2-1 is the spring control chamber Ⅱ of the control component Ⅱ 3, and the side of the valve rod 3-2 far from the main spool 2-1 is the hydraulic control chamber Ⅱ of the control component Ⅱ 3. The spring seat Ⅰ 3-3 and the spring seat Ⅱ 3-4 are located in the spring control chamber Ⅱ, and both the spring seat Ⅰ 3-3 and the spring seat Ⅱ 3-4 are sleeved on the valve rod 3-2. The spring 3-5 is arranged between the spring seat Ⅰ 3-3 and the spring seat Ⅱ 3-4, and there is an axial movement space between the spring seat Ⅰ 3-3 and the spring seat Ⅱ 3-4. One end of the spring seat Ⅰ 3-3 far from the spring 3-5 is limited by the valve body 2, and one end of the spring seat Ⅱ 3-4 far from the spring 3-5 is limited by the head of the valve rod 3-2. A third working oil port X2 communicating with the hydraulic control chamber Ⅱ is provided on the spring end cover 3-1, and the third working oil port X2 is also connected to the seventh working oil port X6 through an external pipeline.

[0046] As Figure 3 and Figure 4 shown in the figure, it can be seen from the structure of the control structure that the main spool throttle groove (the first main spool throttle groove a or the second main spool throttle groove b) of the main spool 2-1, the output pressure P of the pilot chamber Y5 Y5 and the fixed liquid resistance 1-6 form a C-type hydraulic half-bridge, as Figure 6 shown in the figure.

[0047] According to the characteristics of the C-type hydraulic half-bridge, it can be known that changing the flow area of the main spool throttle groove can adjust the output pressure P of the pilot chamber Y5 Y5 .

[0048] Output pressure P of the pilot chamber Y5 Y5 Also determines the position of the buffer spool 1-2, that is, determines the flow area of the throttling groove c of the first buffer spool and the flow area of the throttling groove d of the second buffer spool.

[0049] The hydraulic control schematic diagram of the control structure of the hydraulic directional valve is as Figure 5 shown. In the control structure, the fourth working oil port X3 and the fifth working oil port X4 are respectively connected to the pilot valve. The operator controls the on-off and pressure of the fourth working oil port X3 and the fifth working oil port X4 by operating the pilot valve; the first working oil port X0 is connected to the pilot oil source of the host system (the pressure is a fixed value). Combining Figures 3 to 5 , taking the example of pushing the main spool 2-1 to move to the right to switch the hydraulic control directional valve to the left working position, the working principle of the control structure of the present invention is as follows: The fourth working oil port X3 supplies oil, and the fifth working oil port X4 returns oil. The operator operates the pilot valve, and the hydraulic oil enters the fourth working oil port X3. The hydraulic oil entering the fourth working oil port X3 is divided into two paths. One path enters the sixth working oil port X5 through the sixth oil passage Y7, the throttling groove c of the first buffer spool, and the seventh oil passage Y8, and the other path enters the sixth working oil port X5 through the one-way valve Ⅰ1-4. The hydraulic oil entering the sixth working oil port X5 enters the second working oil port X1 through the external pipeline. The hydraulic pressure in the hydraulic control chamber Ⅰ of the control component Ⅰ1 increases to overcome the elastic force provided by the spring 3-5 and pushes the main spool 2-1 to move to the right, realizing the commutation of the hydraulic check valve. During this process, the first working oil port X0 is connected to the fourth oil passage Y4 through the first oil passage Y1 and the throttling groove a of the first main spool. The hydraulic oil provided by the first working oil port X0 flows to the pilot chamber Y5 through the fourth oil passage Y4. Under the action of the hydraulic pressure in the pilot chamber Y5, it overcomes the elastic force provided by the spring in the spring control chamber ⅠY11 and pushes the buffer spool 1-2 to move to the right. The flow areas of the throttling groove c of the first buffer spool and the throttling groove d of the second buffer spool both gradually increase as the buffer spool 1-2 gradually moves to the right. During the process of the main spool 2-1 moving to the right, the hydraulic oil in the hydraulic control chamber Ⅱ of the control component Ⅱ3 enters the seventh working oil port X6 through the external pipeline, and flows to the fifth working oil port X4 through the eighth oil passage Y9, the throttling groove d of the second buffer spool, and the ninth oil passage Y10 and finally flows back to the fuel tank. The oil discharge port of the spring control chamber ⅠY11 is also connected to the fuel tank. During the process of the buffer spool 1-2 moving to the right, the hydraulic oil in the pilot chamber Y5 flows through the fifth oil passage Y6 and the fixed liquid resistance 1-6 to the spring control chamber ⅠY11 and finally flows to the fuel tank. The fixed liquid resistance 1-6 serves as the oil discharge hole of the pilot chamber Y5. In addition, changing the specification of the fixed liquid resistance 1-6 can adjust the response performance of the buffer spool 1-2 to the main spool 2-1, better match with the hydraulic system, and obtain a better buffering effect.

[0050] During the process of the main spool 2-1 moving to the right as described above, it can be seen that the movement speed of the main spool 2-1 is affected by the pilot pressure of the fourth working oil port X3 and the throttle groove d of the second buffer spool. When fine micro-operations are required by the staff, a relatively low pilot pressure is provided to the fourth working oil port X3. In this way, the oil pressure in the hydraulic control chamber I of the control component I1 is also relatively low, and the displacement of the main spool 2-1 moving to the right is small, resulting in a small flow-through area of the first main spool throttle groove a. Consequently, the oil pressure provided to the pilot chamber Y5 from the first working oil port X0 through the first oil passage Y1, the first main spool throttle groove a, and the fourth oil passage Y4 is also low. The displacement of the buffer spool 1-2 moving to the right is small, making the flow-through area of the second buffer spool throttle groove d small. Therefore, the movement of the main spool 2-1 can be stably controlled. When the pilot pressure of the fourth working oil port X3 increases, the oil pressure in the hydraulic control chamber I of the control component I1 also increases accordingly, and the speed of the main spool 2-1 moving to the right increases. As the displacement of the main spool 2-1 moving to the right increases, the flow-through area of the first main spool throttle groove a increases, and the oil pressure provided to the pilot chamber Y5 from the first working oil port X0 through the first oil passage Y1, the first main spool throttle groove a, and the fourth oil passage Y4 also increases. The displacement of the buffer spool 1-2 continues to increase with the increase in the oil pressure in the pilot chamber Y5. The flow-through areas of the first main spool throttle groove a and the second buffer spool throttle groove d also continue to increase, and the oil return speed of the hydraulic oil in the hydraulic control chamber II of the control component II3 through the second buffer spool throttle groove d is also increased, thereby further increasing the speed of the main spool 2-1 moving to the right, and the main spool 2-1 can be quickly opened. Additionally, as Figure 5 shown, the buffering effect depends on the flow-through areas of the first main spool throttle groove a and the second buffer spool throttle groove d on the buffer spool 1-2. Generally, it is considered that a small flow-through area has a buffering effect, and when the flow-through area is large to a certain extent, it can be regarded as having no buffering effect.

[0051] When the hydraulically controlled directional valve returns from the left working position to the neutral position, the fourth working oil port X3 is connected to the return oil. Under the elastic force provided by the spring 3-5, the main spool 2-1 is pushed to move leftward. The hydraulic oil in the hydraulic control chamber I of the control assembly I flows through the second working oil port X1 and the external pipeline to the sixth working oil port X5. Due to the existence of the check valve I 1-4, the hydraulic oil entering the sixth working oil port X5 cannot flow through the axial hole I 1-7 to the fourth working oil port X3. It can only flow through the seventh oil passage Y8, the throttling groove c of the first buffer spool, and the sixth oil passage Y7 to the fourth working oil port X3 and finally return to the fuel tank. When the main spool 2-1 starts to reset, the throttling area of the throttling groove c of the first buffer spool is relatively large, and the hydraulic oil in the hydraulic control chamber I of the control assembly I returns to the fourth working oil port X3 through the throttling groove c of the first buffer spool at a relatively fast speed. Therefore, the reset speed of the main spool 2-1 is relatively fast. As the main spool 2-1 moves leftward for reset, the throttling area of the first main spool throttling groove a on the main spool 2-1 gradually becomes smaller, and the oil pressure provided to the pilot chamber Y5 from the first working oil port X0 through the first oil passage Y1, the first main spool throttling groove a, and the fifth working oil port X4 gradually decreases. Under the push of the elastic force provided by the spring in the spring control chamber I Y11, the buffer spool 1-2 moves leftward, and the throttling area of the throttling groove c of the first buffer spool becomes smaller, thereby throttling the reset of the main spool 2-1 and reducing the movement speed of the main spool 2-1.

[0052] The working process of switching the hydraulically controlled directional valve to the right working position (returning oil from the fourth working oil port X3 and supplying oil from the fifth working oil port X4) and the working process of the hydraulically controlled directional valve returning from the right working position to the neutral position (connecting the fifth working oil port X4 to the return oil) are similar to the principle described above and will not be elaborated here.

[0053] In some embodiments, such as Figure 3 and Figure 4As shown, the one-way valve I 1-4 includes a mounting seat I 1-41 and a piston I 1-42. An axial through-hole I is provided on the piston I 1-42. A spring I is provided between the mounting seat I 1-41 and the piston I 1-42. An axially connected hole I 1-7 is provided between the fourth working oil port X3 and the sixth working oil port X5. The one-way valve I 1-4 is axially mounted on the end cover 1-1 through the mounting seat I 1-41. Initially, under the action of the spring I, the side of the piston I 1-42 away from the spring I passes through the fourth working oil port X3 and abuts against the orifice of the axial hole I, so that the fourth working oil port X3 and the axial hole I are in a cut-off state. The working principle of the one-way valve I 1-4 is as follows: when the fourth working oil port X3 supplies oil, the hydraulic oil can overcome the spring I and push the piston I 1-42 to move leftward, so that the fourth working oil port X3 and the sixth working oil port X5 are connected through the axial hole I 1-7, and the hydraulic oil can flow from the fourth working oil port X3 to the sixth working oil port X5. When the fourth working oil port X3 returns oil, since the pressure of the hydraulic oil entering the sixth working oil port X5 is relatively low, in addition, the sixth working oil port X5 is connected to the side of the piston I 1-42 close to the spring through the through-hole I, and it cannot overcome the elastic force provided by the spring I to push the piston I 1-42 to move leftward, and the axial hole I 1-7 and the fourth working oil port X3 are in a cut-off state.

[0054] As Figure 3 and Figure 4 shown, the one-way valve II 1-5 includes a mounting seat II 1-51 and a piston II 1-52. An axial through-hole II is provided on the piston II 1-52. A spring II is provided between the mounting seat II 1-51 and the piston II 1-52. An axially connected hole II 1-8 is provided between the fifth working oil port X4 and the seventh working oil port X6. The one-way valve II 1-5 is axially mounted on the end cover 1-1 through the mounting seat II 1-51. Initially, under the action of the spring II, the side of the piston II 1-52 away from the spring II passes through the fifth working oil port X4 and abuts against the orifice of the axial hole II, so that the fifth working oil port X4 and the axial hole II are in a cut-off state. The working principle of the one-way valve II 1-5 is the same as that of the one-way valve I 1-4.

[0055] The above description is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A control structure of a hydraulic directional control valve, characterized in that: The control structure includes control component I (1) and control component II (3), and control component I (1) and control component II (3) are respectively located on both sides of the valve body (2); The control component I (1) includes an end cover (1-1), a buffer spool (1-2), a check valve I (1-4) and a check valve II (1-5); a hole I (1-11) and a hole II (1-12) are provided inside the end cover (1-1); a first working oil port and a second working oil port that are both communicated with the hole I (1-11) are provided on the end cover (1-1), and a fourth working oil port, a fifth working oil port, a sixth working oil port and a seventh working oil port that are both communicated with the hole II (1-12) are provided on the end cover (1-1); The check valve I (1-4) is arranged between the fourth working oil port and the sixth working oil port, and the check valve I (1-4) conducts unidirectionally from the fourth working oil port to the sixth working oil port, and the check valve II (1-5) is arranged between the fifth working oil port and the seventh working oil port, and the check valve II (1-5) conducts unidirectionally from the fifth working oil port to the seventh working oil port; The fourth working oil port is also communicated with the sixth working oil port through the hole II (1-12) and the first buffer spool throttle groove, and the fifth working oil port is also communicated with the seventh working oil port through the hole II (1-12) and the second buffer spool throttle groove; The main spool (2-1) of the valve body (2) extends into the hole I (1-11), and the control component I (1) is provided with a hydraulic control cavity I for controlling the main spool (2-1), and the second working oil port is respectively communicated with the hydraulic control cavity I and the sixth working oil port; The buffer spool (1-2) is placed in the hole II (1-12), and the control component I (1) is provided with a spring control cavity I and a pilot cavity that are both used for controlling the buffer spool (1-2), the spring control cavity I and the pilot cavity are respectively located on both sides of the buffer spool (1-2), the buffer spool (1-2) is axially provided with a fifth oil passage connecting the spring control cavity I and the pilot cavity, a fixed liquid resistance (1-6) is arranged in the fifth oil passage, and an oil discharge port communicated with the spring control cavity I is provided on the end cover (1-1); The control component II (3) includes a valve rod (3-2) connected to the main spool (2-1) of the valve body (2), and the control component II (3) includes a spring control cavity II and a hydraulic control cavity II that are both used for controlling the valve rod (3-2), the spring control cavity II and the hydraulic control cavity II are respectively located on both sides of the valve rod (3-2); the control component II (3) is provided with a third working oil port communicated with the hydraulic control cavity II, and the third working oil port is also communicated with the seventh working oil port; When the control structure is in the initial position state, the first working oil port is in a cut-off state with the pilot cavity of the control component I (1); When the control structure is in the working position state, the first working oil port is communicated with the pilot cavity of the control component I (1) through the hole I (1-11) and the main spool throttle groove; The first oil passage, the second oil passage and the third oil passage are provided on the hole Ⅰ (1-11). The first oil passage is located between the second oil passage and the third oil passage, and the first oil passage is communicated with the first working oil port. The main spool throttle groove includes a first main spool throttle groove and a second main spool throttle groove. Both the first main spool throttle groove and the second main spool throttle groove are communicated with the first oil passage. The first main spool throttle groove is arranged on the side close to the second oil passage, and the second main spool throttle groove is arranged on the side close to the third oil passage. The sixth oil passage, the seventh oil passage, the eighth oil passage and the ninth oil passage are successively arranged on the hole Ⅱ (1-12). The sixth oil passage is communicated with the fourth working oil port, the seventh oil passage is communicated with the sixth working oil port, the eighth oil passage is communicated with the seventh working oil port, and the ninth oil passage is communicated with the fifth working oil port. The first buffer spool throttle groove is respectively communicated with the sixth oil passage and the seventh oil passage, and the second buffer spool throttle groove is respectively communicated with the eighth oil passage and the ninth oil passage. It further includes a fourth oil passage. One end of the fourth oil passage is connected with the pilot chamber of the control component Ⅰ (1), and the other end of the fourth oil passage is respectively connected with the second oil passage and the third oil passage.

2. The control structure of a hydraulic directional control valve according to claim 1, characterized in that: The flow area of the first main spool throttle groove gradually becomes smaller from the first oil passage side to the second oil passage side. The flow area of the second main spool throttle groove gradually becomes smaller from the first oil passage side to the third oil passage side. The flow area of the first buffer spool throttle groove gradually becomes smaller from the sixth oil passage side to the seventh oil passage side. The flow area of the second buffer spool throttle groove gradually becomes smaller from the eighth oil passage side to the ninth oil passage side.

3. The control structure of a hydraulic directional control valve according to claim 1, characterized in that: When the main spool (2-1) of the valve body (2) is in the middle position, the first main spool throttle groove is in a cut-off state with the second oil passage, and the second main spool throttle groove is in a cut-off state with the third oil passage. When the main spool (2-1) of the valve body (2) is in the left working position, the first main spool throttle groove is communicated with the second oil passage, and the second main spool throttle groove is in a cut-off state with the third oil passage. When the main spool (2-1) of the valve body (2) is in the right working position, the first main spool throttle groove is in a cut-off state with the second oil passage, and the second main spool throttle groove is conducted with the third oil passage.

4. The control structure of a hydraulic directional control valve according to claim 1, characterized in that: The control component Ⅱ (3) includes a spring end cover (3-1), a spring seat Ⅰ (3-3), a spring seat Ⅱ (3-4) and a spring (3-5). The valve stem (3-2) is placed in the inner cavity of the spring end cover (3-1). Both the spring seat Ⅰ (3-3) and the spring seat Ⅱ (3-4) are sleeved on the valve stem (3-2). The spring (3-5) is arranged between the spring seat Ⅰ (3-3) and the spring seat Ⅱ (3-4). One end of the spring seat Ⅰ (3-3) far away from the spring (3-5) is limited by the valve body (2), and one end of the spring seat Ⅱ (3-4) far away from the spring (3-5) is limited by the valve stem (3-2).

5. The control structure of a hydraulic directional control valve according to claim 1, characterized in that: The one-way valve I (1-4) includes a mounting seat I (1-41) and a piston I (1-42). An axial through-hole I is provided on the piston I (1-42). A spring I is provided between the mounting seat I (1-41) and the piston I (1-42). An axial hole I for communication is provided between the fourth working oil port and the sixth working oil port. The one-way valve I (1-4) is axially mounted on the end cover (1-1) through the mounting seat I (1-41). Initially, under the action of the spring I, the side of the piston I (1-42) away from the spring I passes through the fourth working oil port and closely adheres to the orifice of the axial hole I, so that the fourth working oil port and the axial hole I are in a cut-off state.

6. The control structure of a hydraulic directional control valve according to claim 1, characterized in that: The one-way valve II (1-5) includes a mounting seat II (1-51) and a piston II (1-52). An axial through-hole II is provided on the piston II (1-52). A spring II is provided between the mounting seat II (1-51) and the piston II (1-52). An axial hole II for communication is provided between the fifth working oil port and the seventh working oil port. The one-way valve II (1-5) is axially mounted on the end cover (1-1) through the mounting seat II (1-51). Initially, under the action of the spring II, the side of the piston II (1-52) away from the spring II passes through the fifth working oil port and closely adheres to the orifice of the axial hole II, so that the fifth working oil port and the axial hole II are in a cut-off state.

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