Overflow valve and construction machinery having the same

Abstract

The present invention provides an overflow valve and a construction machine having the same. The overflow valve includes a valve body, a first valve core, an adjusting sleeve, a spring seat, a first elastic member, a valve sleeve, a second valve core, a plug and a second elastic member. By setting the rated load and elastic constant of the second elastic member, the present invention can achieve the characteristics of the boost mode a3, further improve the set pressure during start-up acceleration and deceleration stop, increase it from the existing Pf to Ph, enhance the start-up acceleration and deceleration stop characteristics, and improve production efficiency. At the same time, the movement time of the valve sleeve is extended, making the boost mode during this operation more stable, reducing impact, and thus improving the operability of the hydraulic excavator. The technical solution of the present invention solves the defect that the overflow valve in the prior art is difficult to balance production efficiency and operability.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic components, and particularly to a relief valve and a construction machinery having the same. Background Art

[0002] The relief valve is mainly used for actuators with large rotational inertia such as hydraulic excavators. The general working process of the relief valve in the prior art is that high-pressure oil pushes the valve core through the high-pressure port to overflow at a lower pressure, and another part of the high-pressure oil flows into the rightmost end of the valve core shaft through the inner cavity of the valve core. The high-pressure oil flows into the oil cavity through the holes and grooves on the side wall of the valve core and through the annular throttling channel. The pressure oil flowing into the oil cavity further flows into the oil cavity through the holes. The pressure oil pushes the spring seat in the oil cavity to compress the spring, so that the pressure of the relief valve gradually increases until the end of the spring seat contacts the step of the main valve body. During this process, by setting the gap of the annular throttling channel, the amount of oil flowing into the oil cavity can be adjusted, and thus the movement time of the spring seat can be controlled to achieve a buffering effect, reduce impact, and improve the operability of the hydraulic excavator rotation. However, with the further improvement of the requirements for the production efficiency and operating performance of construction machinery, especially hydraulic excavators, the relief valve in the prior art cannot improve the production efficiency while improving the operability. As Figure 1 shown, by setting different gaps of the annular throttling channel, boost modes a1 and a2 can be obtained, and the time t1 and t2 are respectively delayed to reach the highest pressure setting value. In mode a1, the buffering time is longer, which can reduce the impact during deceleration and stop, but the transition time during start-up acceleration and deceleration and stop is prolonged, resulting in a reduction in the production efficiency of the excavator. In mode a2, the buffering time is short, and the impact during deceleration and stop cannot be avoided, resulting in a decline in operability. It can be seen that in the case of high-pressure setting of the set pressure Pf, it is difficult for the relief valve according to the prior art to take into account both production efficiency and operability. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the relief valve in the prior art is difficult to take into account both production efficiency and operability, so as to provide a relief valve and a construction machinery having the same.

[0004] To solve the above problems, the present invention provides a relief valve, comprising: a valve body; a first valve core movably disposed within the valve body, a first throttle hole provided at a first end of the first valve core, a first oil passage provided within the first valve core, one end of the first oil passage communicating with the first throttle hole, the other end of the first oil passage penetrating through a second end of the first valve core; an adjusting sleeve disposed within the valve body, the adjusting sleeve being located at the second end of the first valve core; a spring seat disposed within the valve body and on a side of the adjusting sleeve facing the first valve core; a first elastic member, with two ends of the first elastic member respectively abutting against the first end of the first valve core and the spring seat; a valve sleeve movably disposed within the adjusting sleeve, a first end of the valve sleeve being adapted to cooperate with the spring seat, the second end of the first valve core passing through the first end of the valve sleeve, a second throttle hole provided on a side wall of the valve sleeve; a second valve core movably disposed within the valve sleeve, a third throttle hole provided at a first end of the second valve core, a second oil passage provided within the second valve core, a first end of the second oil passage communicating with the third throttle hole, a second end of the second oil passage penetrating through a second end of the second valve core, a fourth throttle hole communicating with the second oil passage provided on a side wall of the second valve core, and when the second valve core moves, the fourth throttle hole can be aligned with or misaligned with the second throttle hole; a plug provided at an end of the adjusting sleeve facing away from the first valve core, a first receiving recess provided on the plug, the second end of the valve sleeve being disposed within the first receiving recess, and a gap existing between an outer side wall of the valve sleeve and the plug; a second elastic member provided between the second valve core and the plug.

[0005] Optionally, a first limiting convex edge is provided on an outer side wall of the valve sleeve, a first stepped surface is provided on an inner side wall of the adjusting sleeve, and the first limiting convex edge is located between the first stepped surface and an end surface of the plug.

[0006] Optionally, the relief valve further comprises a fixed seat, the fixed seat is disposed within the valve sleeve and in abutting contact with the plug, and the second elastic member is provided between the second valve core and the fixed seat.

[0007] Optionally, the fixed seat is movably disposed within the valve sleeve.

[0008] Optionally, a second receiving recess is provided on an end surface of the fixed seat facing the second valve core, the second elastic member is a spring, one end of the second elastic member abuts against a bottom wall of the second oil passage, and the other end of the second elastic member abuts against a bottom wall of the second receiving recess.

[0009] Optionally, a limiting structure is provided on an inner side wall of the valve sleeve, and the limiting structure limits a moving position of the second valve core in a direction towards the first valve core.

[0010] Optionally, the limiting structure is a limiting ring provided on the inner side wall of the valve sleeve.

[0011] Optionally, a second step surface and a third step surface are provided on the end surface of the spring seat facing the second valve core. The third step surface is located outside the second step surface. Among them, the second step surface is adapted to cooperate with the end of the valve sleeve, and the third step surface is adapted to cooperate with the end of the adjusting sleeve.

[0012] Optionally, a second limiting convex edge is provided on the outer side wall of the first valve core. The first elastic member is a spring. One end of the first elastic member abuts against the second limiting convex edge, and the other end of the first elastic member abuts against the spring seat.

[0013] The present invention also provides a construction machine, including the above-mentioned overflow valve.

[0014] The present invention has the following advantages:

[0015] Using the technical solution of the present invention, high-pressure oil enters the first oil passage through the first throttle hole of the first valve core, and then flows into the valve sleeve through the second end of the first valve core. The high-pressure oil flows in the valve sleeve to the outside of the third throttle hole of the second valve core, and enters the second oil passage through the third throttle hole, and flows to the outside of the valve sleeve through the fourth throttle hole and the second throttle hole. When the hydraulic oil pressure reaches a predetermined value (that is, Figure 6 Pi in it), the hydraulic oil flows into the gap between the valve sleeve and the plug, and pushes the valve sleeve to move towards the first valve core. When the valve sleeve moves, it pushes the spring seat to move, thereby increasing the elastic force of the first elastic member and realizing pressure boost. During this process, due to the throttling effect of the third throttle hole, the high-pressure oil simultaneously pushes the second valve core to move towards the plug against the elastic force of the second elastic member, and finally makes the fourth throttle hole and the second throttle hole misaligned. The high-pressure oil in the gap continuously pushes the spring seat and makes it move to a predetermined position.

[0016] For the above-mentioned overflow valve, by setting the rated load and elastic constant of the second elastic member, the characteristics of the pressure boost mode a3 as shown in Figure 6 can be realized, further improving the set pressure during start-up acceleration and deceleration stop, increasing it from the existing Pf to Ph, enhancing the start-up acceleration and deceleration stop characteristics, and improving production efficiency. At the same time, the movement time of the valve sleeve is extended, making the pressure boost mode during this operation more stable, reducing shock, and thus improving the operability of the hydraulic excavator. Therefore, the technical solution of the present invention solves the defect that the overflow valve in the prior art is difficult to balance production efficiency and operability. Description of the Drawings

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 A schematic diagram showing the relationship between the operating pressure and the operating time of the overflow valve in the prior art;

[0019] Figure 2 A schematic structural diagram of the overflow valve of the present invention;

[0020] Figure 3 Shows Figure 2 An enlarged schematic diagram at position A in

[0021] Figure 4 Shows Figure 2 An enlarged schematic diagram at position B in

[0022] Figure 5 Shows Figure 2 An enlarged schematic diagram at position C in ; and

[0023] Figure 6 A schematic diagram showing the relationship between the operating pressure and the operating time of the overflow valve of the present invention in the figure.

[0024] Explanation of reference numerals:

[0025] 10. Valve body; 20. First spool; 21. First throttle hole; 22. First oil passage; 23. Second limiting convex edge; 30. Adjusting sleeve; 31. First step surface; 40. Spring seat; 41. Second step surface; 42. Third step surface; 50. First elastic member; 60. Valve sleeve; 61. Second throttle hole; 62. First limiting convex edge; 70. Second spool; 71. Third throttle hole; 72. Second oil passage; 73. Fourth throttle hole; 80. Plug; 81. First accommodating recess; 90. Second elastic member; 100. Fixed seat; 101. Second accommodating recess; 110. Limiting structure; h. Gap. Specific embodiments

[0026] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] The overflow valve of this embodiment includes a valve body 10, a first valve core 20, an adjusting sleeve 30, a spring seat 40, a first elastic member 50, a valve sleeve 60, a second valve core 70, a plug 80 and a second elastic member 90. The following will first introduce each of the above components in detail.

[0031] As Figure 2 and Figure 3 shown, the first valve core 20 is movably arranged in the valve body 10. A first throttle hole 21 is provided at the first end of the first valve core 20, and a first oil passage 22 is arranged inside the first valve core 20. One end of the first oil passage 22 is communicated with the first throttle hole 21, and the other end of the first oil passage 22 penetrates through the second end of the first valve core 20. Specifically, the first end of the first valve core 20 is also the Figure 2 left end in Figure 2 , and the second end of the first valve core 20 is also the Figure 2 right end in Figure 3 . When the overflow valve works, high-pressure oil acts on the first valve core 20, and the first valve core 20 is opened under the action of the pressure difference. Part of the high-pressure oil flows back to the fuel tank, and the other part of the oil flows into the internal first oil passage 22 through the first throttle hole 21. Combining

[0032] As Figure 1As shown, the adjusting sleeve 30 is arranged inside the valve body 10, and the spring seat 40 is arranged inside the valve body 10 and on the side of the adjusting sleeve 30 facing the first valve core 20. Specifically, the adjusting sleeve 30 is located at the second end of the first valve core 20, and the right end of the valve body 10 is sleeved on the left end of the adjusting sleeve 30, and the two are connected by threads. Therefore, those skilled in the art can understand that rotating the adjusting sleeve 30 can adjust the axial relative position between the adjusting sleeve 30 and the valve body 10, and the left end of the adjusting sleeve 30 cooperates with the spring seat 40. Therefore, the adjusting sleeve 30 can adjust the initial position of the spring seat 40, and further adjust the initial elastic force exerted by the first elastic member 50 on the first valve core 20 (that is, Figure 6 Pi in

[0033] As Figure 2 and Figure 3 shown, the two ends of the first elastic member 50 are respectively abutted against the first end of the first valve core 20 and the spring seat 40. High-pressure oil can push the first valve core 20 to overcome the elastic force of the first elastic member 50 and open. Those skilled in the art can understand that the process of compressing the first elastic member 50 is the horizontal section process corresponding to Figure 6 Pi in

[0034] As Figure 2 , Figure 4 and Figure 5 shown, the valve sleeve 60 is movably arranged inside the adjusting sleeve 30. The first end of the valve sleeve 60 is adapted to cooperate with the spring seat 40. The second end of the first valve core 20 is inserted into the first end of the valve sleeve 60, and a second throttle hole 61 is arranged on the side wall of the valve sleeve 60. Specifically, the valve sleeve 60 can move axially, so that the spring seat 40 further moves to the left on the basis of the initial position, thereby increasing the operating pressure (that is, Figure 6 Pi in

[0035] As Figure 2 and Figure 5As shown, the second spool 70 is movably disposed within the valve sleeve 60. A third throttle hole 71 is provided at the first end of the second spool 70. A second oil passage 72 is provided within the second spool 70. The first end of the second oil passage 72 communicates with the third throttle hole 71. The second end of the second oil passage 72 penetrates through the second end of the second spool 70. A fourth throttle hole 73 communicating with the second oil passage 72 is provided on the side wall of the second spool 70. When the second spool 70 moves, the fourth throttle hole 73 can be aligned or misaligned with the second throttle hole 61. Specifically, the pressure oil further flows into the second oil passage 72 through the third throttle hole 71 of the second spool 70. Since the area of the third throttle hole 71 is set small enough, a pressure loss is generated therewith. The equation for the pressure loss Δp of the throttle hole is as follows:

[0036] Formula:

[0037] Wherein, q is the oil flow rate through the third throttle hole 71, A is the area of the third throttle hole 71, c is the flow coefficient, and Δp is the pressure difference across the third throttle hole 71. When the flow rate of the pressure oil through the third throttle hole 71 increases, the pressure difference therebetween becomes larger, and the pressure of the high-pressure oil overcomes the elastic force of the second elastic member 90, causing the second spool 70 to move to the right in the figure.

[0038] As Figure 2 and Figure 5 shown, the plug 80 is disposed at the end of the adjusting sleeve 30 facing away from the first spool 20. A first receiving recess 81 is provided on the plug 80. The second end of the valve sleeve 60 is disposed within the first receiving recess 81, and there is a gap h between the outer side wall of the valve sleeve 60 and the plug 80. Further, the plug 80 closes the right end of the adjusting sleeve 30, and a sealing structure is provided therebetween.

[0039] As Figure 2 and Figure 5 shown, the second elastic member 90 is disposed between the second spool 70 and the plug 80. The second elastic member 90 is used to adjust the moving pressure of the second spool 70 and can reset the second spool 70.

[0040] Using the technical solution of this embodiment, the high-pressure oil enters the first oil passage 22 through the first throttle hole 21 of the first spool 20, and then flows into the valve sleeve 60 through the second end of the first spool 20. The high-pressure oil flows to the outside of the third throttle hole 71 of the second spool 70 within the valve sleeve 60, enters the second oil passage 72 through the third throttle hole 71, and flows to the outside of the valve sleeve 60 through the fourth throttle hole 73 and the second throttle hole 61. When the pressure of the hydraulic oil reaches a predetermined value (i.e., Figure 6When the pressure reaches Pi), the hydraulic oil flows into the gap between the valve sleeve 60 and the plug 80, and pushes the valve sleeve 60 towards the first spool 20. When the valve sleeve 60 moves, it pushes the spring seat 40 to move, thereby increasing the elastic force of the first elastic member 50 to achieve pressure boost. During this process, due to the throttling effect of the third throttle orifice 71, the high-pressure oil simultaneously pushes the second spool 70 to move towards the plug 80 against the elastic force of the second elastic member 90, and finally causes the fourth throttle orifice 73 and the second throttle orifice 61 to be misaligned. The high-pressure oil in the gap continuously pushes the spring seat 40 and makes it move to a predetermined position.

[0041] For the above-mentioned overflow valve, by setting the rated load and elastic constant of the second elastic member 90, the characteristics of the pressure boost mode a3 as shown in Figure 6 can be achieved, further improving the set pressure during start-up acceleration and deceleration stop, increasing it from the existing Pf to Ph, enhancing the start-up acceleration and deceleration stop characteristics, and improving production efficiency. At the same time, the movement time of the valve sleeve is extended, making the pressure boost mode during this operation more stable, reducing the impact, and thus improving the operability of the hydraulic excavator. Therefore, the technical solution of this embodiment solves the defect that the overflow valve in the prior art is difficult to balance production efficiency and operability.

[0042] As Figure 5 shown, in the technical solution of this embodiment, a first limiting convex edge 62 is provided on the outer side wall of the valve sleeve 60, and a first stepped surface 31 is provided on the inner side wall of the adjusting sleeve 30. The first limiting convex edge 62 is located between the first stepped surface 31 and the end surface of the plug 80. The first limiting convex edge 62 can only move between the first stepped surface 31 and the left end surface of the plug 80, so it has the effect of restricting the axial movement of the valve sleeve 60.

[0043] As Figure 5 shown, in the technical solution of this embodiment, the overflow valve further includes a fixed seat 100. The fixed seat 100 is arranged in the valve sleeve 60 and is in abutting contact with the plug 80. The second elastic member 90 is arranged between the second spool 70 and the fixed seat 100. Specifically, the fixed seat 100 is a cylindrical structure with one end open, and the opening of the fixed seat 100 faces the second spool 70. Further, when the second spool 70 moves to abut against the fixed seat 100, the fourth throttle orifice 73 and the second throttle orifice 61 are completely misaligned.

[0044] Preferably, the fixed seat 100 is movably arranged in the valve sleeve 60.

[0045] As Figure 5As shown, in the technical solution of this embodiment, a second receiving recess 101 is provided on the end face of the fixed seat 100 facing the second valve core 70. The second elastic member 90 is a spring. One end of the second elastic member 90 abuts against the bottom wall of the second oil passage 72, and the other end of the second elastic member 90 abuts against the bottom wall of the second receiving recess 101. The above structure facilitates the installation of the second elastic member 90.

[0046] As Figure 5 shown, in the technical solution of this embodiment, a limiting structure 110 is provided on the inner side wall of the valve sleeve 60. The limiting structure 110 limits the moving position of the second valve core 70 in the direction towards the first valve core 20. And preferably, the limiting structure 110 is a limiting ring provided on the inner side wall of the valve sleeve 60.

[0047] As Figure 4 shown, in the technical solution of this embodiment, a second step surface 41 and a third step surface 42 are provided on the end face of the spring seat 40 facing the second valve core 70. The third step surface 42 is located outside the second step surface 41. Among them, the second step surface 41 is adapted to cooperate with the end of the valve sleeve 60, and the third step surface 42 is adapted to cooperate with the end of the adjusting sleeve 30. Specifically, the third step surface 42 protrudes from the second step surface 41.

[0048] As Figure 1 and Figure 2 shown, in the technical solution of this embodiment, a second limiting convex edge 23 is provided on the outer side wall of the first valve core 20. The first elastic member 50 is a spring. One end of the first elastic member 50 abuts against the second limiting convex edge 23, and the other end of the first elastic member 50 abuts against the spring seat 40. The above structure facilitates the installation of the first elastic member 50.

[0049] This embodiment also provides a construction machinery, including the above-mentioned overflow valve. Preferably, the construction machinery is an excavator. Of course, other construction machinery equipped with an overflow valve can adopt the above-mentioned overflow valve structure.

[0050] According to the above description, this patent application can improve the production efficiency of a hydraulic excavator while taking into account its operability. By forming a flow control valve with a pressure-compensated flow adjustment valve core, a fixed piston, a buffer spring, and a valve sleeve, the set pressure during startup acceleration and deceleration stop is further increased, improving the swing startup acceleration and deceleration stop characteristics and the production efficiency of the excavator; at the same time, the pressure rise time is extended, reducing the impact and improving the operability of the hydraulic excavator.

[0051] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or alterations derived therefrom still fall within the protection scope of the present invention.

Claims

1. An overflow valve, characterized in that, Comprising: Valve body (10); A first spool (20), movably arranged within the valve body (10), a first throttling orifice (21) is provided at a first end of the first spool (20), a first oil passage (22) is provided within the first spool (20), one end of the first oil passage (22) communicates with the first throttling orifice (21), and the other end of the first oil passage (22) penetrates through a second end of the first spool (20). An adjusting sleeve (30), arranged within the valve body (10), and the adjusting sleeve (30) is located at the second end of the first spool (20); A spring seat (40), arranged within the valve body (10) and located on a side of the adjusting sleeve (30) facing the first spool (20); A first elastic member (50), with two ends of the first elastic member (50) respectively abutting against the first end of the first spool (20) and the spring seat (40); A valve sleeve (60), movably arranged within the adjusting sleeve (30), a first end of the valve sleeve (60) is adapted to cooperate with the spring seat (40), a second end of the first spool (20) is inserted into the first end of the valve sleeve (60), and a second throttling orifice (61) is provided on a side wall of the valve sleeve (60); A second spool (70), movably arranged within the valve sleeve (60), a third throttling orifice (71) is provided at a first end of the second spool (70), a second oil passage (72) is provided within the second spool (70), a first end of the second oil passage (72) communicates with the third throttling orifice (71), a second end of the second oil passage (72) penetrates through a second end of the second spool (70), and a fourth throttling orifice (73) communicating with the second oil passage (72) is provided on a side wall of the second spool (70). When the second spool (70) moves, the fourth throttling orifice (73) can be aligned or misaligned with the second throttling orifice (61); A plug (80), arranged on an end of the adjusting sleeve (30) facing away from the first spool (20), a first receiving recess (81) is provided on the plug (80), a second end of the valve sleeve (60) is arranged within the first receiving recess (81), and there is a gap (h) between an outer side wall of the valve sleeve (60) and the plug (80); A second elastic member (90), arranged between the second spool (70) and the plug (80); The overflow valve further includes a fixing seat (100), the fixing seat (100) is arranged within the valve sleeve (60) and is in abutting contact with the plug (80), and the second elastic member (90) is arranged between the second spool (70) and the fixing seat (100); The fixing seat (100) is movably arranged within the valve sleeve (60); A limiting structure (110) is provided on an inner side wall of the valve sleeve (60), and the limiting structure (110) limits a moving position of the second spool (70) in a direction towards the first spool (20).

2. The overflow valve according to claim 1, characterized in that, A first limiting convex edge (62) is provided on the outer side wall of the valve sleeve (60), a first stepped surface (31) is provided on the inner side wall of the adjusting sleeve (30), and the first limiting convex edge (62) is located between the first stepped surface (31) and the end face of the plug (80).

3. The overflow valve according to claim 1, characterized in that, A second receiving recess (101) is provided on the end face of the fixed seat (100) facing the second valve core (70), the second elastic member (90) is a spring, one end of the second elastic member (90) abuts against the bottom wall of the second oil passage (72), and the other end of the second elastic member (90) abuts against the bottom wall of the second receiving recess (101).

4. The overflow valve according to claim 1, characterized in that, The limiting structure (110) is a limiting ring provided on the inner side wall of the valve sleeve (60).

5. The overflow valve according to claim 1, characterized in that, A second stepped surface (41) and a third stepped surface (42) are provided on the end face of the spring seat (40) facing the second valve core (70), the third stepped surface (42) is located outside the second stepped surface (41), wherein the second stepped surface (41) is adapted to cooperate with the end of the valve sleeve (60), and the third stepped surface (42) is adapted to cooperate with the end of the adjusting sleeve (30).

6. The overflow valve according to claim 1, characterized in that, A second limiting convex edge (23) is provided on the outer side wall of the first valve core (20), the first elastic member (50) is a spring, one end of the first elastic member (50) abuts against the second limiting convex edge (23), and the other end of the first elastic member (50) abuts against the spring seat (40).

7. An engineering machinery, characterized in that, Comprising a relief valve according to any one of claims 1 to 6.

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