A differential control system for automatically switching the speed of a hydraulic cylinder

Abstract

The application discloses a differential control system for automatically converting the high speed and low speed of a hydraulic oil cylinder and relates to the technical field of hydraulic control. The differential control system comprises a first two-way cartridge valve, a second two-way cartridge valve, a third two-way cartridge valve, a control component and a conversion component. The control component can maintain the pressure of the C port of the third two-way cartridge valve. When the hydraulic pressure in the plug cavity reaches a first hydraulic value, the control component can make the C port of the third two-way cartridge valve communicate with the oil return port, so that the hydraulic oil in the rod cavity flows through the A port and the B port of the third two-way cartridge valve and flows to the oil return port. The conversion component can make the hydraulic oil in the rod cavity flow through the B port and the A port of the first two-way cartridge valve, mix with the hydraulic oil flowing into the oil inlet and flow into the plug cavity through the A port and the B port of the second two-way cartridge valve. The differential control system for automatically converting the high speed and low speed of the hydraulic oil cylinder has the advantages of simple structure, convenient operation, automatic conversion of the differential fast forward and slow forward, reduced equipment use cost and failure rate and improved work efficiency of the equipment.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, and in particular to a differential control system for automatic switching between fast and slow speeds of a hydraulic cylinder. Background Technology

[0002] With the rapid development of production technology and the gradual maturation of hydraulic equipment, improving the efficiency and speed of hydraulic equipment has become a key development direction. To increase the working speed of hydraulic cylinders without increasing the hydraulic power source, hydraulic differential control circuits have emerged. Utilizing the characteristics of differential circuits, the cylinders can operate at high speeds under low load conditions, while the differential is cut off under high load conditions, and pressure is applied via the working feed. Currently, the differential control circuits on in-use equipment require either pressure or position signals for switching between differential fast advance and working feed. Figure 1 As shown, the forward pressure of the hydraulic cylinder 9 is monitored by the pressure signaling element 7 or the forward displacement of the hydraulic cylinder 9 is monitored by the position signaling element 8. Then, the action of the two-position four-way solenoid directional valve 12 is controlled according to the pressure signal or displacement signal, so that the rod chamber 92 is depressurized to realize the differential fast advance to work feed action. Such a setting increases the equipment cost and the failure point, and is likely to affect the work efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a differential control system for automatic switching between fast and slow speeds of a hydraulic cylinder, in order to solve the problems existing in the prior art. It has a simple structure, is easy to operate, and can automatically switch between differential fast advance and working advance, thereby reducing equipment operating costs and failure rates, and improving equipment working efficiency.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] The application provides a differential control system for automatic conversion of hydraulic cylinder speed, comprising a first two-way cartridge valve, a second two-way cartridge valve, a third two-way cartridge valve, a control component and a conversion component; the A port and the B port of the first two-way cartridge valve are respectively connected with an oil inlet and a rod cavity; the A port and the B port of the second two-way cartridge valve are respectively connected with the oil inlet and a plug cavity; the A port and the B port of the third two-way cartridge valve are respectively connected with the rod cavity and an oil return port; the control component is connected with the C port of the third two-way cartridge valve, the oil return port and the plug cavity; the control component can maintain the pressure of the C port of the third two-way cartridge valve, and when the hydraulic pressure in the plug cavity reaches a first hydraulic value, the control component can connect the C port of the third two-way cartridge valve with the oil return port, so that the hydraulic oil in the rod cavity flows through the A port and the B port of the third two-way cartridge valve and flows to the oil return port; the conversion component is connected with the oil inlet, the C port of the first two-way cartridge valve, the C port of the second two-way cartridge valve and the oil return port; the conversion component can connect the C port of the first two-way cartridge valve with the oil inlet, and connect the C port of the second two-way cartridge valve with the oil return port, so that the hydraulic oil in the rod cavity can flow through the B port and the A port of the first two-way cartridge valve and mix with the hydraulic oil from the oil inlet, and then the mixed hydraulic oil flows into the plug cavity through the A port and the B port of the second two-way cartridge valve.

[0006] Preferably, the control component comprises a pilot sequence valve, and the P port, the X port and the T port of the pilot sequence valve are respectively connected with the C port of the third two-way cartridge valve, the plug cavity and the oil return port.

[0007] Preferably, the control component comprises a pilot sequence valve, and the P port, the X port and the T port of the pilot sequence valve are respectively connected with the C port of the third two-way cartridge valve, the plug cavity and the oil return port.

[0008] Preferably, the conversion component comprises a three-position four-way electromagnetic reversing valve, and the P port, the A port, the B port and the T port of the three-position four-way electromagnetic reversing valve are respectively connected with the oil inlet, the C port of the second two-way cartridge valve, the C port of the first two-way cartridge valve and the oil return port; when the cross end of the three-position four-way electromagnetic reversing valve is powered, the P port of the three-position four-way electromagnetic reversing valve is connected with the B port to connect the C port of the first two-way cartridge valve with the oil inlet, and the A port of the three-position four-way electromagnetic reversing valve is connected with the T port to connect the C port of the second two-way cartridge valve with the oil return port.

[0009] Preferably, a fourth two-way cartridge valve is further provided, and the A port, the B port and the C port of the fourth two-way cartridge valve are respectively connected with the plug cavity, the oil return port and the B port of the three-position four-way electromagnetic reversing valve; the hydraulic oil in the plug cavity can flow through the A port and the B port of the fourth two-way cartridge valve to flow to the oil return port.

[0010] Preferably, the sum of the areas of the A port and the B port of the first two-way cartridge valve is equal to the area of the C port of the first two-way cartridge valve.

[0011] The present application achieves the following technical effects relative to the prior art:

[0012] The hydraulic cylinder fast / slow automatic conversion differential control system provided by the present application, in the process of differential fast forward movement of the hydraulic cylinder: the conversion component makes the C port of the second two-way cartridge valve communicate with the oil return port, so that the hydraulic oil in the C port of the second two-way cartridge valve can flow to the oil return port to make the A port and the B port of the second two-way cartridge valve communicate, and the conversion component can also make the C port of the first two-way cartridge valve communicate with the oil inlet port, so that the pressure in the A port of the first two-way cartridge valve is the same as that in the C port, and the A port and the B port of the first two-way cartridge valve do not communicate, and the control component maintains the pressure in the C port of the third two-way cartridge valve, so that the A port and the B port of the third two-way cartridge valve do not communicate; in this way, the oil inlet port is connected to the hydraulic oil, and the hydraulic oil enters the plug cavity of the hydraulic cylinder through the A port and the B port of the second two-way cartridge valve to realize forward movement; in the process of forward movement, since the hydraulic oil in the rod cavity cannot flow to the oil return port through the A port of the third two-way cartridge valve, the pressure in the rod cavity gradually increases, and after the pressure in the B port of the first two-way cartridge valve is continuously increased to be greater than the pressure in the C port, the first two-way cartridge valve opens to make the A port and the B port communicate, and the hydraulic oil in the rod cavity can mix with the hydraulic oil in the oil inlet port through the B port and the A port of the first two-way cartridge valve and enter the plug cavity through the second two-way cartridge valve to realize differential fast forward movement.

[0013] When the hydraulic cylinder forward movement runs and contacts the load, the pressure in the plug cavity gradually increases, and since the control component communicates with the plug cavity, when the pressure in the plug cavity reaches the first hydraulic value, the control component controls the C port of the third two-way cartridge valve to communicate with the oil return port, so that the hydraulic oil in the C port of the third two-way cartridge valve can flow back to the oil return port to make the A port and the B port communicate, and the hydraulic oil in the rod cavity can flow back to the oil return port through the third two-way cartridge valve, so that the pressure in the B port of the first two-way cartridge valve decreases, the first two-way cartridge valve opens to make the A port and the B port not communicate, thereby releasing the differential forward movement to realize slow forward movement; in this way, the control component communicates with the pressure in the plug cavity to realize automatic conversion of the differential and the forward movement, and the structure is simple and convenient to operate, without the need for external electrical signaling elements to detect signaling, which improves the working efficiency of the equipment and reduces the use cost and failure rate of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described below only show some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0015] Figure 1 The control chart of the differential hydraulic system for the first embodiment;

[0016] Figure 2 The control chart of the differential control system for the fast and slow automatic conversion of the hydraulic cylinder provided by the first embodiment.

[0017] In the figure: 1-the first two-way cartridge valve; 2-the oil inlet; 3-the second two-way cartridge valve; 4-the third two-way cartridge valve; 5-the oil return; 6-the pilot sequence valve; 7-the pressure signaling element; 8-the position signaling element; 9-the oil cylinder; 91-the plug cavity; 92-the rod cavity; 10-the three-position four-way electromagnetic reversing valve; 11-the fourth two-way cartridge valve; 12-the two-position four-way electromagnetic reversing valve. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0019] The purpose of the present application is to provide a differential control system for the fast and slow automatic conversion of a hydraulic cylinder, so as to solve the problems in the prior art, and the differential fast forward and slow forward can be automatically converted, the use cost and failure rate of the equipment are reduced, and the working efficiency of the equipment is improved.

[0020] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Embodiment one

[0022] The present embodiment provides a differential control system for the fast and slow automatic conversion of a hydraulic cylinder, please refer to Figure 2, including the first two-way cartridge valve 1, the second two-way cartridge valve 3, the third two-way cartridge valve 4, the control component and the conversion component; the A port and the B port of the first two-way cartridge valve 1 are communicated with the oil inlet 2 and the rod cavity 92 respectively; the A port and the B port of the second two-way cartridge valve 3 are communicated with the oil inlet 2 and the plug cavity 91 respectively; the A port and the B port of the third two-way cartridge valve 4 are communicated with the rod cavity 92 and the oil return port 5 respectively; the control component is communicated with the C port of the third two-way cartridge valve 4, the oil return port 5 and the plug cavity 91, the control component can maintain the pressure of the C port of the third two-way cartridge valve 4, and when the hydraulic pressure in the plug cavity 91 reaches the first hydraulic value, the control component can make the C port of the third two-way cartridge valve 4 communicated with the oil return port 5, so that the hydraulic oil in the rod cavity 92 flows through the A port and the B port of the third two-way cartridge valve 4 and flows to the oil return port 5; the conversion component is communicated with the oil inlet 2, the C port of the first two-way cartridge valve 1, the C port of the second two-way cartridge valve 3 and the oil return port 5, the conversion component can make the C port of the first two-way cartridge valve 1 communicated with the oil inlet 2, and make the C port of the second two-way cartridge valve 3 communicated with the oil return port 5, so that the hydraulic oil in the rod cavity 92 can flow through the B port and the A port of the first two-way cartridge valve 1 and mix with the hydraulic oil flowing into the oil inlet 2, and the hydraulic oil flows into the plug cavity 91 through the A port and the B port of the second two-way cartridge valve 3.

[0023] During the differential quick forward movement of the oil cylinder 9: the conversion component makes the C port of the second two-way cartridge valve 3 communicated with the oil return port 5, so that the hydraulic oil in the C port of the second two-way cartridge valve 3 can flow to the oil return port 5 to make the A port and the B port of the second two-way cartridge valve 3 communicated, and the conversion component can also make the C port of the first two-way cartridge valve 1 communicated with the oil inlet 2, so that the pressure of the A port and the C port of the first two-way cartridge valve 1 is the same, and the A port and the B port of the first two-way cartridge valve 1 are not communicated, and the control component maintains the pressure of the C port of the third two-way cartridge valve 4, so that the A port and the B port of the third two-way cartridge valve 4 are not communicated, so that the hydraulic oil flowing into the oil inlet 2 realizes forward movement by entering the plug cavity 91 of the oil cylinder 9 through the A port and the B port of the second two-way cartridge valve 3, and during the forward movement, the pressure in the rod cavity 92 of the oil cylinder 9 gradually rises, and when the pressure in the rod cavity 92 is greater than the pressure in the C port of the first two-way cartridge valve 1, the first two-way cartridge valve 1 is opened to make the A port and the B port communicated, so that the hydraulic oil in the rod cavity 92 can mix with the hydraulic oil flowing into the oil inlet 2 through the B port and the A port of the first two-way cartridge valve 1, and enter the plug cavity 91 through the second two-way cartridge valve 3, to realize differential quick forward movement;

[0024] Slow-speed pressurized feed operation of hydraulic cylinder 9: After the hydraulic cylinder moves forward and contacts the load, the pressure in the plug chamber 91 gradually increases. Since the control component is connected to the plug chamber 91, after the pressure in the plug chamber 91 reaches the first hydraulic value, the control component controls the C port of the third two-way cartridge valve 4 to connect to the return port. The hydraulic oil in the C port of the third two-way cartridge valve 4 can flow back to the return port 5, connecting its A port and B port. The hydraulic oil in the rod chamber 92 can flow back to the return port 5 through the third two-way cartridge valve 4, thereby reducing the pressure on the B port of the first two-way cartridge valve 1. The first two-way cartridge valve 1 opens, preventing the A port and B port from connecting, thereby releasing the differential forward movement and realizing slow-speed feed operation.

[0025] Compared to Figure 1 The traditional differential hydraulic system shown can be improved by adding a pressure signaling element 7 or a position signaling element 8 and a two-position four-way solenoid directional valve 12 to control the oil discharge in the lever chamber 92. The system has a simple structure, is easy to operate, and does not require external electrical signaling elements for detection and signaling. This improves the working efficiency of the equipment and reduces the equipment operating cost and failure rate.

[0026] The oil inlet 2 connects to an external oil storage device to supply hydraulic oil, and the oil return port 5 connects to the oil tank to return hydraulic oil.

[0027] In the optional scheme of this embodiment, more preferably, the control component includes a pilot sequence valve 6. The P port, X port and T port of the pilot sequence valve 6 are respectively connected to the C port, the plug chamber 91 and the return port 5 of the third two-way cartridge valve 4. By setting the pilot sequence valve 6, the automatic conversion between differential fast advance and working advance is realized. The conversion pressure of the hydraulic cylinder 9 from fast advance to working advance can be arbitrarily set by the opening pressure of the pilot sequence valve 6, i.e., the first hydraulic value. No external electrical signaling element is required for detection and signaling, which improves the working efficiency of the equipment and reduces the equipment operating cost and failure rate. Pilot sequence valves of models such as DZ10-1-30 / 21X or DZC-1-30 / 20 can be used.

[0028] In the optional embodiment, more preferably, the switching component includes a three-position four-way solenoid directional valve 10. The P port, A port, B port, and T port of the three-position four-way solenoid directional valve 10 are respectively connected to the oil inlet 2, the C port of the second two-way cartridge valve 3, the C port of the first two-way cartridge valve 1, and the return port 5. During differential rapid advance, when the cross end of the three-position four-way solenoid directional valve 10 is energized, the P port and B port of the three-position four-way solenoid directional valve 10 are connected so that the C port of the first two-way cartridge valve 1 is connected to the oil inlet 2, so that the pressure of the A port and C port of the first two-way cartridge valve 1 is the same. The A port and T port of the three-position four-way solenoid directional valve 10 are connected so that the C port of the second two-way cartridge valve 3 is connected to the return port 5. The second two-way cartridge valve 3 is opened so that the A port and B port are connected, so that hydraulic oil can enter the plug cavity 91.

[0029] Further, the sum of the areas of the A port and the B port of the first two-way plug-in valve 1 is equal to the area of the C port of the first two-way plug-in valve 1; the A port and the B port of the first two-way plug-in valve 1 are simultaneously pressed, due to the difference in the area ratio of the plug cavity 91 and the rod cavity 92 of the oil cylinder 9, the pressure in the rod cavity 92 is greater than the pressure in the plug cavity 91 and the system hydraulic oil pressure of the oil inlet port 2, the sum of the areas of the A port and the B port of the first two-way plug-in valve 1 is equal to the area of the C port, the pressure of the A port and the C port of the first two-way plug-in valve 1 is equal, due to the force pushing open of the A port and the B port of the first two-way plug-in valve 1, the C port is forced to close, when the pressure of the B port under the hydraulic action of the rod cavity 92 is greater than the pressure of the A port and the C port, the opening force is greater than the closing force, so that the first two-way plug-in valve 1 is passively pushed open, the oil in the rod cavity 92 flows into the B port and the A port of the first two-way plug-in valve 1 and mixes with the hydraulic oil of the oil inlet port 2, and then enters the plug cavity 92 through the second two-way plug-in valve 3, thereby forming differential action.

[0030] In an optional solution of the embodiment, preferably, the hydraulic oil cylinder fast / slow automatic conversion differential control system provided by the embodiment further comprises a fourth two-way plug-in valve 11, the A port, the B port and the C port of the fourth two-way plug-in valve 11 are respectively in communication with the plug cavity 91, the oil return port 5 and the B port of the three-position four-way electromagnetic reversing valve 10; the hydraulic oil in the plug cavity 91 can flow through the A port and the B port of the fourth two-way plug-in valve 11 to the oil return port 5; the return action of the oil cylinder 9 is realized through the fourth two-way plug-in valve 11, specifically, during the return action, the parallel end of the three-position four-way electromagnetic reversing valve 10 is electrified, the P port and the A port thereof are in communication, the B port and the T port are in communication, the communication between the P port and the A port makes the second two-way plug-in valve 3 close and the first two-way plug-in valve 1 open, the communication between the B port and the T port makes the fourth two-way plug-in valve 11 open, the oil return port 5 is connected to the B port of the third two-way plug-in valve 4 and the B port of the fourth two-way plug-in valve 11 through the oil return pipeline, the hydraulic oil in the plug cavity 91 flows back to the oil return port 5 through the A port and the B port of the fourth two-way plug-in valve 11, and the return action is accelerated by introducing hydraulic oil into the oil inlet port 2 and then into the rod cavity 92 through the first two-way plug-in valve 1.

[0031] The principles and implementation manners of the present application are described by using specific examples in the present application; the above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the present description should not be understood as a limitation of the present application.

Claims

1. A differential control system for automatic conversion of the speed of a hydraulic cylinder, characterized in that: It comprises: a first two-way cartridge valve (1), the A port and the B port of which are communicated with an oil inlet (2) and a rod cavity (92) respectively; a second two-way cartridge valve (3), the A port and the B port of which are communicated with the oil inlet (2) and a plug cavity (91) respectively; a third two-way cartridge valve (4), the A port and the B port of which are communicated with the rod cavity (92) and an oil return (5) respectively; a control component, which comprises a pilot sequence valve (6), the P port, the X port and the T port of which are communicated with the C port of the third two-way cartridge valve (4), the plug cavity (91) and the oil return (5) respectively; the control component can maintain the pressure of the C port of the third two-way cartridge valve (4), and when the hydraulic pressure in the plug cavity (91) reaches a first hydraulic pressure value, the control component can make the C port of the third two-way cartridge valve (4) communicated with the oil return (5), so that the hydraulic oil in the rod cavity (92) flows through the A port and the B port of the third two-way cartridge valve (4) and flows to the oil return (5); and a conversion component, which is communicated with the oil inlet (2), the C port of the first two-way cartridge valve (1), the C port of the second two-way cartridge valve (3) and the oil return (5); the conversion component can make the C port of the first two-way cartridge valve (1) communicated with the oil inlet (2), and make the C port of the second two-way cartridge valve (3) communicated with the oil return (5), so that the hydraulic oil in the rod cavity (92) can flow through the B port and the A port of the first two-way cartridge valve (1) and mix with the hydraulic oil from the oil inlet (2), and then the hydraulic oil flows into the plug cavity (91) through the A port and the B port of the second two-way cartridge valve (3).

2. The hydraulic cylinder slow-fast automatic switching differential control system according to claim 1, characterized in that: The conversion component comprises a three-position four-way electromagnetic reversing valve (10), the P port, the A port, the B port and the T port of which are communicated with the oil inlet (2), the C port of the second two-way cartridge valve (3), the C port of the first two-way cartridge valve (1) and the oil return (5) respectively; When the cross end of the three-position four-way electromagnetic reversing valve (10) is energized, the P port of the three-position four-way electromagnetic reversing valve (10) is communicated with the B port to make the C port of the first two-way cartridge valve (1) communicated with the oil inlet (2), and the A port of the three-position four-way electromagnetic reversing valve (10) is communicated with the T port to make the C port of the second two-way cartridge valve (3) communicated with the oil return (5).

3. The hydraulic cylinder slow-fast automatic switching differential control system according to claim 2, characterized in that: It further comprises a fourth two-way cartridge valve (11), the A port, the B port and the C port of which are communicated with the plug cavity (91), the oil return (5) and the B port of the three-position four-way electromagnetic reversing valve (10) respectively; the hydraulic oil in the plug cavity (91) can flow through the A port and the B port of the fourth two-way cartridge valve (11) to flow to the oil return (5).

4. The hydraulic cylinder slow-fast automatic switching differential control system according to claim 1, characterized in that: The sum of the areas of the A port and the B port of the first two-way cartridge valve (1) is equal to the area of the C port of the first two-way cartridge valve (1).

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