Hydraulic control system for automatic cylinder return

Abstract

The application discloses an oil cylinder automatic return hydraulic control system, which comprises an oil cylinder unit, a control unit and a signal oil port formed on the cylinder barrel, wherein the oil cylinder unit is provided with a cylinder barrel and a piston rod capable of reciprocating in the cylinder barrel, the cylinder barrel is divided into a rod cavity and a rodless cavity by the piston rod, the rodless cavity is connected with a first pipeline, and the rod cavity is connected with a second pipeline; and the control unit is provided with a first control pipeline; and the first control pipeline is connected with the signal oil port; wherein, in the state that the signal oil port is communicated with the rodless cavity, the first control pipeline is configured to adjust the flow direction of the fluid medium flowing through the first pipeline and the fluid medium flowing through the second pipeline. The application solves the problems of complicated structure and tedious operation of the current automatic return hydraulic control system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic cylinder control, and particularly relates to an automatic hydraulic control system for cylinder back-off. BACKGROUND

[0002] At present, the construction conditions of large hydraulic equipment are various, and in many conditions, the load needs to be back-off by the operator after moving a certain distance driven by the hydraulic cylinder (for example, the drill needs to be back-off by the operator when the drill reaches the top of the push beam). In order to improve the construction efficiency, ensure the construction safety, and reduce the loss caused by the operator's negligence without operating the cylinder back-off, the automatic back-off function of the hydraulic cylinder is needed. The existing automatic back-off control system has complex structure and cumbersome operation, and has many unreasonable places. SUMMARY

[0003] The present application provides an automatic hydraulic control system for cylinder back-off, which solves the problems of complex structure and cumbersome operation of the existing automatic back-off hydraulic control system.

[0004] The above implementation purposes of the present application are mainly realized by the following technical solutions:

[0005] The present application provides an automatic hydraulic control system for cylinder back-off, which solves the problems of complex structure and cumbersome operation of the existing automatic back-off hydraulic control system.

[0006] The cylinder unit has a cylinder barrel and a piston rod which can move reciprocally in the cylinder barrel, the cylinder barrel is divided into a rod cavity and a rodless cavity by the piston rod, the rodless cavity is connected with a first pipeline, and the rod cavity is connected with a second pipeline;

[0007] The control unit has a first control pipeline and a signal oil port formed on the cylinder barrel, the first control pipeline is connected with the signal oil port; wherein, in the state that the signal oil port is communicated with the rodless cavity, the first control pipeline is configured to adjust the flow direction of the fluid medium flowing through the first pipeline and the fluid medium flowing through the second pipeline.

[0008] In a preferred embodiment of the present application, the control unit further includes a second control pipeline, the second control pipeline is communicated with the signal oil port, and in the state that the signal oil port is communicated with the rod cavity, the second control pipeline is configured to cut off the control operation of the first control pipeline to the first pipeline and the second pipeline.

[0009] In a preferred embodiment of the present application, the first control pipeline includes a first reversing valve and a first reversing switch pipe, the first reversing valve has a first working position which can push the piston rod to extend out of the cylinder barrel, and a second working position which can make the piston rod retract into the cylinder barrel;

[0010] The first reversing valve can be switched from the first working position to the second working position in a state where the fluid medium in the rodless cavity flows into the first reversing switch pipe.

[0011] In a preferred embodiment of the present application, the first reversing valve has an oil inlet, an oil return, a first oil outlet, a second oil outlet and a hydraulic control end, the first reversing switch pipe is connected to the hydraulic control end of the first reversing valve, and the first pipeline and the second pipeline are respectively connected to the first oil outlet of the first reversing valve and the second oil outlet of the first reversing valve.

[0012] In a state where the first reversing valve is in the first working position, the fluid medium flows into the rodless cavity of the cylinder through the oil inlet, the first oil outlet and the first pipeline, and the fluid medium in the rod cavity of the cylinder flows out of the first reversing valve through the second pipeline, the second oil outlet and the oil return.

[0013] In a state where the first reversing valve is in the second working position, the fluid medium flows into the rod cavity of the cylinder through the oil inlet, the second oil outlet and the second pipeline, and the fluid medium in the rodless cavity of the cylinder flows out of the first reversing valve through the first pipeline, the first oil outlet and the oil return.

[0014] In a preferred embodiment of the present application, the second control pipeline comprises a second reversing valve and a second reversing switch pipe, the second reversing valve has a third working position capable of connecting the first reversing switch pipe and a fourth working position capable of disconnecting the first reversing switch pipe.

[0015] In a state where the fluid medium in the rodless cavity flows into the first reversing switch pipe and the second reversing switch pipe respectively, the second reversing valve can be switched from the fourth working position to the third working position.

[0016] In a preferred embodiment of the present application, the second reversing valve has an oil inlet, an oil outlet, a first hydraulic control end and a second hydraulic control end, the oil inlet and the oil outlet are located on the first reversing switch pipe, one end of the second reversing switch pipe is connected to the signal oil port, the other end is connected to the second hydraulic control end, and the second pipeline is connected to the first hydraulic control end.

[0017] In a preferred embodiment of the present application, a first pressure reducing valve is arranged on the first pipeline, and the first pressure reducing valve is connected with an overflow valve.

[0018] In a preferred embodiment of the present application, a one-way valve is arranged on the first pipeline in parallel with the pressure reducing valve.

[0019] In a preferred embodiment of the present application, the first reversing switch pipe is provided with a second pressure reducing valve, which is located between the liquid control end of the first reversing valve and the oil outlet of the second reversing valve.

[0020] In a preferred embodiment of the present application, the liquid control end of the first reversing valve is connected with a damping pipeline connected with an oil tank, the first reversing switch pipe is connected with the liquid control end of the first reversing valve through the damping pipeline, and a damper is arranged on the damping pipeline and located at the downstream end of the first reversing switch pipe.

[0021] In a preferred embodiment of the present application, the first reversing valve has a manual control end, which can switch the first reversing valve from the first working position or the second working position to a non-working position in which the piston rod is in a static state.

[0022] In a preferred embodiment of the present application, the first reversing valve is a three-position four-way reversing valve, and the second reversing valve is a two-position two-way reversing valve.

[0023] Compared with the prior art, the technical scheme of the present application has the following characteristics and advantages:

[0024] 1. The control unit connected with the signal oil port is arranged on the cylinder barrel in the present application, the control unit is used for controlling the flow direction of the fluid medium in the first pipeline and the second pipeline connected with the cylinder barrel, thereby the automatic retraction of the piston rod in the cylinder barrel can be realized, the structure is simple, the design is novel and reasonable, the use range is wide, and the safety and reliability are high.

[0025] 2. The first pressure reducing valve is arranged on the first pipeline in the present application, the overflow valve is connected with the first pressure reducing valve, the working pressure of the fluid medium in the first pipeline is controlled through the cooperation of the first pressure reducing valve and the overflow valve; the one-way valve is connected in parallel with the first pressure reducing valve, the one-way flow direction of the one-way valve is the same as the flow direction of the fluid medium in the first pipeline when the fluid medium flows out of the rodless chamber, and the one-way valve makes the first pressure reducing valve work only in one direction, that is, the first pressure reducing valve works when the fluid medium flows into the rodless chamber, and the first pressure reducing valve does not work when the fluid medium flows out of the rodless chamber. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work. In the drawings:

[0027] Figure 1Structure diagram of the first communication state of the oil cylinder automatic return hydraulic control system according to the application;

[0028] Figure 2 Structure diagram of the second communication state of the oil cylinder automatic return hydraulic control system according to the application;

[0029] Figure 3 Structure diagram of the third communication state of the oil cylinder automatic return hydraulic control system according to the application;

[0030] Figure 4 Structure diagram of the fourth communication state of the oil cylinder automatic return hydraulic control system according to the application.

[0031] Explanation of reference numerals:

[0032] 10, oil cylinder unit; 11, cylinder barrel; 111, first oil port; 112, second oil port; 113, signal oil port; 12, piston rod; 13, rod cavity; 14, rodless cavity; 15, first pipeline; 16, second pipeline;

[0033] 20, control unit; 21, first control pipeline; 211, first reversing switch pipe; 22, second control pipeline; 221, second reversing switch pipe;

[0034] 30, first reversing valve; 31, first working position; 32, second working position; 33, hydraulic control end; 34, manual control end; 35, non-working position;

[0035] 40, second reversing valve; 41, third working position; 42, fourth working position; 43, first hydraulic control end; 44, second hydraulic control end;

[0036] 50, first pressure reducing valve; 51, overflow valve; 52, check valve; 53, second pressure reducing valve;

[0037] 60, damping pipeline; 61, damper;

[0038] 70, oil tank;

[0039] A, first oil outlet; B, second oil outlet; C, oil inlet; D, oil outlet; P, oil inlet; T, oil return port. DETAILED DESCRIPTION

[0040] In order to make the technical solution in the present application better understood by the person skilled in the art, the technical solution in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative work should belong to the protection scope of the present application.

[0041] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "left", "right", and similar terms as used herein are for purposes of illustration and description only and are not meant to be limiting.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] As shown in Figures 1 to 4 The present application provides an oil cylinder automatic return hydraulic control system, which can realize the function of automatically returning the piston rod 12 in the oil cylinder to the original position, and the oil cylinder automatic return hydraulic control system comprises:

[0044] An oil cylinder unit 10, which has a cylinder barrel 11 and a piston rod 12 capable of reciprocating in the cylinder barrel 11, the cylinder barrel 11 is divided into a rod cavity 13 and a rodless cavity 14 by the piston rod 12, the rodless cavity 14 is connected with a first pipeline 15, and the rod cavity 13 is connected with a second pipeline 16.

[0045] A control unit 20, which has a first control pipeline 21 and a signal oil port 113 formed on the cylinder barrel 11, the first control pipeline 21 is connected with the signal oil port 113; wherein, in the state that the signal oil port 113 is communicated with the rodless cavity 14, the first control pipeline 21 is configured to adjust the flow direction of the fluid medium flowing through the first pipeline 15 and the fluid medium flowing through the second pipeline 16.

[0046] The oil cylinder automatic back-off hydraulic control system of the present application is provided with a control unit 20 connected with a signal oil port 113 on the cylinder barrel 11, the control unit 20 is used to control the flow direction of the fluid medium in the first pipeline 15 and the second pipeline 16 connected with the cylinder barrel 11, thereby realizing the extension and retraction operation of the piston rod 12 inside the cylinder barrel 11, the structure is simple, the design is novel and reasonable, the use range is wide and it is safe and reliable.

[0047] Specifically, as shown in Figure 1 The oil cylinder unit 10 has a cylinder barrel 11 and a piston rod 12 located in the cylinder barrel 11 and capable of moving along the inner wall of the cylinder barrel 11 under the push of the fluid medium, the piston rod 12 includes a piston and a push rod, the piston divides the internal space of the cylinder barrel 11 into a rod cavity 13 with the push rod and a rodless cavity 14 without the push rod. In this embodiment, the side wall of the cylinder barrel 11 is provided with a first oil port 111 corresponding to the position of the rodless cavity 14, the first oil port 111 is connected with the first pipeline 15, the first pipeline 15 is used to pass the fluid medium into the rodless cavity 14 or discharge the fluid medium in the rodless cavity 14; the side wall of the cylinder barrel 11 is provided with a second oil port 112 corresponding to the position of the rod cavity 13, the second oil port 112 is connected with the second pipeline 16, the second pipeline 16 is used to pass the fluid medium into the rod cavity 13 or discharge the fluid medium in the rod cavity 13, in the present application, the fluid medium is hydraulic oil. As shown in Figure 2 When the first pipeline 15 passes the hydraulic oil into the rodless cavity 14 and the second pipeline 16 discharges the hydraulic oil in the rod cavity 13, the piston rod 12 moves in the X direction, at this time, the oil cylinder is in the pushing stroke, and the piston rod 12 performs the pushing operation; as shown in Figure 4 When the first pipeline 15 discharges the hydraulic oil in the rodless cavity 14 and the second pipeline 16 passes the hydraulic oil into the rod cavity 13, the piston rod 12 moves in the direction opposite to the X direction, at this time, the oil cylinder is in the back-off stroke, and the piston rod 12 performs the back-off operation.

[0048] The side wall of the cylinder barrel 11 is further provided with a signal oil port 113, which is located between the first oil port 111 and the second oil port 112, and can be communicated with the rod cavity 13 or the rodless cavity 14 according to the position of the piston in the cylinder barrel 11, that is, the signal oil port 113 is located in the stroke range of the piston rod 12, and the piston in the piston rod 12 can pass the signal oil port 113 during movement. The signal oil port 113 is connected with the first control pipeline 21. Due to the change of the position of the piston rod 12, the signal oil port 113 can be switched between being communicated with the rod cavity 13 and being communicated with the rodless cavity 14, so that the pressure of the hydraulic oil in the signal oil port 113 changes according to the position of the piston rod 12, and then the pressure of the hydraulic oil in the first control pipeline 21 changes; in this embodiment, the first control pipeline 21 is configured to adjust the flow direction of the hydraulic oil flowing through the first pipeline 15 and the hydraulic oil flowing through the second pipeline 16; specifically, when the oil cylinder is in the above-mentioned pushing stroke state, the piston rod 12 moves in the X direction, and when the piston in the piston rod 12 passes the signal oil port 113 in the X direction, the pressure of the hydraulic oil in the first control pipeline 21 changes, at this time, the first control pipeline 21 can switch the flow direction of the hydraulic oil in the first pipeline 15 and the second pipeline 16 according to the pressure change, in this embodiment, when the above-mentioned pressure change occurs in the first control pipeline 21, the first control pipeline 21 can switch the piston rod 12 from the pushing stroke to the retreat stroke, that is, the automatic retreat of the piston rod 12 in the oil cylinder can be realized.

[0049] Further, as shown in Figure 1 The first control pipeline 21 includes a first reversing valve 30 and a first reversing switch pipe 211, the first reversing valve 30 has a first working position 31 capable of pushing the piston rod 12 to extend out of the cylinder barrel 11, and a second working position 32 capable of retracting the piston rod 12 into the cylinder barrel 11; wherein in the state that the fluid medium in the rodless cavity 14 flows into the first reversing switch pipe 211, the first reversing valve 30 can be switched from the first working position 31 to the second working position 32.

[0050] The first control pipeline 21 of the present application, the first reversing valve 30 is connected on the first pipeline 15 and the second pipeline 16, the first reversing valve 30 can switch the flow direction of the hydraulic oil in the first pipeline 15 and the second pipeline 16, the first reversing switch pipe 211 controls the first reversing valve 30, and then realizes the automatic retreat of the hydraulic rod in the oil cylinder.

[0051] Specifically, as shown in Figures 1 to 3As shown, the first reversing valve 30 is connected to the first pipeline 15 and the second pipeline 16, and is used to switch the flow direction of the hydraulic oil in the first pipeline 15 and the second pipeline 16; in the embodiment, the first reversing valve 30 has an oil inlet P, an oil return port T, a first oil outlet A, a second oil outlet B, and a hydraulic control end 33; the oil inlet P is connected to a hydraulic pump (not shown in the figure), which is used as a power source to send high-pressure hydraulic oil into the oil inlet P, and then drive the piston rod 12 to perform advancing operation or retreating operation through the first pipeline 15 or the second pipeline 16; the first pipeline 15 and the second pipeline 16 are respectively connected to the first oil outlet A of the first reversing valve 30 and the second oil outlet B of the first reversing valve 30; one end of the first reversing switch pipe 211 is connected to the hydraulic control end 33 of the first reversing valve 30, and the other end of the first reversing switch pipe 211 is connected to the signal oil port 113; the first reversing switch pipe 211 senses the pressure of the hydraulic oil of the signal oil port 113, and then transmits the pressure to the hydraulic control end 33 of the first reversing valve 30.

[0052] As shown in FIG. 1, the piston rod 12 is in the advancing stroke, and the piston rod 12 is in the retreating stroke. Figure 2 As shown, in the state that the first reversing valve 30 is in the first working position 31, the fluid medium flows into the rodless cavity 14 of the cylinder barrel 11 through the oil inlet P, the first oil outlet A, and the first pipeline 15, and the fluid medium in the rod cavity 13 of the cylinder barrel 11 flows out of the first reversing valve 30 through the second pipeline 16, the second oil outlet B, and the oil return port T; at this time, the piston rod 12 in the cylinder barrel 11 is in the advancing stroke.

[0053] As shown, in the state that the first reversing valve 30 is in the second working position 32, the fluid medium flows into the rod cavity 13 of the cylinder barrel 11 through the oil inlet P, the second oil outlet B, and the second pipeline 16, and the fluid medium in the rodless cavity 14 of the cylinder barrel 11 flows out of the first reversing valve 30 through the first pipeline 15, the first oil outlet A, and the oil return port T; at this time, the piston rod 12 in the cylinder barrel 11 is in the retreating stroke. Figure 4 Further, in the embodiment, in the state that the piston rod 12 in the oil cylinder is in the advancing stroke, the piston rod 12 moves in the X direction; when the piston in the piston rod 12 passes the signal oil port 113 in the X direction, the pressure of the hydraulic oil at the signal oil port 113 changes, that is, the high-pressure hydraulic oil in the rodless cavity 14 flows into the first reversing switch pipe 211, the first reversing switch pipe 211 connected to the signal oil port 113 transmits the pressure change to the hydraulic control end 33 of the first reversing valve 30, and the hydraulic pressure change of the hydraulic control end 33 controls the first reversing valve 30 to switch from the first working position 31 to the second working position 32, that is, switches the piston rod 12 from the advancing stroke to the retreating stroke, that is, realizes the automatic retreating of the piston rod 12 in the oil cylinder.

[0054] According to one embodiment of the present application, as shown in FIG. 1, the piston rod 12 is in the advancing stroke, and the piston rod 12 is in the retreating stroke.

[0055] Figure 1 ​As shown, the first reversing valve 30 also has a manual control end 34, which can switch the first reversing valve 30 from the first working position 31 or the second working position 32 to a non-working position 35 in which the piston rod 12 is in a stationary state.

[0056] Specifically, in the embodiment, the first reversing valve 30 is a three-position four-way reversing valve, which includes the first working position 31, the second working position 32, and the non-working position 35. Figure 1 As shown, when the first reversing valve 30 (i.e., the three-position four-way reversing valve) is in the non-working position 35, the oil inlet P, the first oil outlet A, the second oil outlet B, and the oil return port T are disconnected, and the piston rod 12 in the oil cylinder stops working.

[0057] The first reversing valve 30 (i.e., the three-position four-way reversing valve) includes a hydraulic control end 33 and a manual control end 34, which can control the switching between the three working positions; the hydraulic control end 33 is controlled by the first reversing switching pipe 211 in the first control pipeline 21, and the hydraulic control end 33 can switch the first reversing valve 30 from the first working position 31 to the second working position 32 under the control of the first control pipeline 21; the manual control end 34 is used for manual control by the staff, and the manual control end 34 can switch the first reversing valve 30 from the first working position 31 or the second working position 32 to the non-working position 35, or from the second working position 32 to the first working position 31, or from the non-working position 35 to the first working position 31 or the second working position 32.

[0058] According to one embodiment of the present application, as shown in Figures 1 to 4 As shown, the control unit 20 also includes a second control pipeline 22, which is connected in communication with the signal oil port 113, and in the state that the signal oil port 113 is connected in communication with the rod cavity 13, the second control pipeline 22 is configured to cut off the control operation of the first control pipeline 21 on the first pipeline 15 and the second pipeline 16.

[0059] The second control pipeline 22 of the present application is connected to the signal oil port 113, and controls the on-off of the first control pipeline 21 through the change of the pressure of the hydraulic oil of the signal oil port 113, thereby controlling the flow direction of the fluid medium in the first pipeline 15 and the second pipeline 16; the two-stage control of the first control pipeline 21 and the second control pipeline 22 can ensure the stability of the fluid medium pressure in the first control pipeline 21, ensure the stable switching between the forward stroke and the return stroke of the piston rod 12 in the oil cylinder, and thereby enable the automatic return of the piston rod 12 to be performed stably.

[0060] Specifically, as shown in Figure 1 and Figure 2As shown, the second control line 22 is connected to the signal oil port 113, and the connection and disconnection of the first reversing switching line 211 are controlled by the hydraulic oil pressure at the signal oil port 113; Figure 1 As shown, with the signal port 113 connected to the rod chamber 13, the second control line 22 controls the first reversing switching pipe 211 to be in the off state, as follows: Figure 3 As shown, when the signal port 113 is connected to the rodless chamber 14, the second control line 22 controls the first reversing switching pipe 211 to be in a connected state. The first reversing switching pipe 211 transmits the pressure of the signal port 113 to the hydraulic control end 33 of the first reversing valve 30, thereby controlling the first reversing valve 30 to switch from the first working position 31 to the second working position 32.

[0061] According to one embodiment of the present invention, such as Figures 1 to 4 As shown, the second control line 22 includes a second reversing valve 40 and a second reversing switching pipe 221. The second reversing valve 40 has a third working position 41 that can connect to the first reversing switching pipe 211 and a fourth working position 42 that can disconnect the first reversing switching pipe 211. When the fluid medium in the rodless chamber 14 flows into the first reversing switching pipe 211 and the second reversing switching pipe 221 respectively, the second reversing valve 40 can switch from the fourth working position 42 to the third working position 41.

[0062] Specifically, in this embodiment, the second directional valve 40 is a two-position two-way directional valve. The second directional valve 40 (two-position two-way directional valve) has an inlet C, an outlet D, a first hydraulic control terminal 43, and a second hydraulic control terminal 44. The inlet C and outlet D are located on the first directional switching pipe 211. That is, the inlet C is connected to the signal port 113 through the first directional switching pipe 211, and the outlet D is connected to the hydraulic control terminal 33 of the first directional valve 30 through the first directional switching pipe 211. The first hydraulic control terminal 43 is connected to the second pipeline 16 and receives the pressure signal from the second port 112 on the rod chamber 13. The second hydraulic control terminal 44 is connected to the signal port 113 through the second directional switching pipe 221 and receives the pressure signal from the signal port 113.

[0063] like Figure 2 As shown, when the signal port 113 is connected to the rod chamber 13, the pressure signal received by the first hydraulic control terminal 43 and the pressure signal received by the second hydraulic control terminal 44 of the second directional valve 40 are both the pressure in the rod chamber 13, and the two are equal. At this time, the second directional valve 40 is in the fourth working position 42, and the oil inlet C and oil outlet D of the second directional valve 40 are disconnected, that is, the first directional switching pipe 211 is disconnected, and the hydraulic control terminal 33 of the first directional valve 30 does not work.

[0064] like Figure 3As shown, when the signal oil port 113 is communicated with the rodless cavity 14, the pressure signal received by the first hydraulic control end 43 of the second reversing valve 40 is the pressure in the rod cavity 13, the pressure signal received by the second hydraulic control end 44 of the second reversing valve 40 is the pressure in the rodless cavity 14, the pressure of the second hydraulic control end 44 is greater than that of the first hydraulic control end 43, at this time, the second reversing valve 40 will be driven by the joint action of the first hydraulic control end 43 and the second hydraulic control end 44 to switch from the fourth working position 42 to the third working position 41. Figure 2 As shown, the fourth working position 42 is switched to the third working position 41. Figure 3 As shown, the third working position 41, at this time, the first reversing switching pipe 211 is communicated, the pressure signal of the signal oil port 113 is transmitted to the hydraulic control end 33 of the first reversing valve 30, and then the first reversing valve 30 is driven to reverse.

[0065] Further, in the embodiment, when the piston rod 12 in the oil cylinder is in the pushing stroke state, the piston rod 12 moves in the X direction, when the piston in the piston rod 12 passes the signal oil port 113 in the X direction, the pressure of the hydraulic oil of the signal oil port 113 changes, that is, the pressure signal in the rodless cavity 14 is transmitted to the second hydraulic control end 44 of the second reversing valve 40 through the second reversing switching pipe 221, and then the second reversing valve 40 is driven to switch from the fourth working position 42 to the third working position 41, that is, the first reversing switching pipe 211 is switched from the disconnected state to the communicated state, the pressure signal of the signal oil port 113 is transmitted to the hydraulic control end 33 of the first reversing valve 30 through the first reversing switching pipe 211, and then the first reversing valve 30 is driven to switch from the first working position 31 to the second working position 32, the piston rod 12 in the oil cylinder is switched from the pushing stroke to the backstroke, as described above, that is, the automatic backstroke of the piston rod 12 of the oil cylinder can be realized.

[0066] According to one embodiment of the present application, as shown in the figure, Figure 2 As shown, the first pipeline 15 is provided with a first pressure reducing valve 50, and the first pressure reducing valve 50 is connected with an overflow valve 51. The overflow valve 51 cooperates with the first pressure reducing valve 50 to adjust the pressure in the rodless cavity 14, and then realizes that the piston rod 12 can stably push different sizes of loads when it is in the pushing stroke state.

[0067] According to one embodiment of the present application, as shown in the figure, Figures 2 to 4 As shown, the first pipeline 15 is provided with a one-way valve 52 which is arranged in parallel with the pressure reducing valve. The one-way valve 52 cooperates with the first pressure reducing valve 50 to control the pressure size of the first pipeline 15 in one direction.

[0068] Specifically, the one-way flow direction of the one-way valve 52 is the same as the flow direction of the hydraulic oil in the first pipeline 15 when the piston rod 12 is in the backstroke; as shown in the figure, Figure 4As shown, when the piston rod 12 is in the back-off stroke state, the hydraulic oil in the first pipeline 15 flows out from the oil return port T through the one-way valve 52 and the first reversing valve 30, the first pressure reducing valve 50 loses the function, the resistance in the back-off stroke can be reduced, and then the output power of the hydraulic pump in the back-off stroke is reduced, and the energy is saved.

[0069] According to one embodiment of the present application, as shown in Figure 3 As shown, the first reversing switch pipe 211 is provided with a second pressure reducing valve 53, which is located between the hydraulic control end 33 of the first reversing valve 30 and the oil outlet D of the second reversing valve 40. The second pressure reducing valve 53 is used to adjust the pressure in the first reversing switch pipe 211 in the communication state, and then realize the adjustment of the pressure of the hydraulic control end 33 of the first reversing valve 30.

[0070] According to one embodiment of the present application, as shown in Figure 3 As shown, the hydraulic control end 33 of the first reversing valve 30 is connected with the damping pipeline 60 connected with the oil tank 70, the first reversing switch pipe 211 is connected with the hydraulic control end 33 of the first reversing valve 30 through the damping pipeline 60, and the damping pipeline 60 is provided with a damper 61 located at the downstream end of the first reversing switch pipe 211. The damper 61 in the damping pipeline 60 is used to release the pressure after keeping the first reversing switch pipe 211 at a certain pressure.

[0071] In order to further illustrate the working principle of the oil cylinder automatic back-off hydraulic control system, the specific working process of the oil cylinder automatic back-off hydraulic control system will be described in combination with the drawings as follows:

[0072] As shown in Figure 1 As shown, the hand control end 34 of the first reversing valve 30 (three-position four-way reversing valve) is operated to be in the non-working position 35, at this time, the hydraulic oil does not flow through the system, and the piston rod 12 in the oil cylinder remains in the static state.

[0073] As shown in Figure 2As shown, operating the hand control end 34 of the first reversing valve 30 to be in the first working position 31, the hydraulic oil in the hydraulic pump enters the rodless chamber 14 through the first pipeline 15, and the hydraulic oil in the rod chamber 13 flows out from the oil return port T of the first reversing valve 30 through the second pipeline 16, the piston rod 12 moves in the X direction under the action of high-pressure hydraulic oil, and is in the pushing stroke to push the load forward; in the state that the piston has not passed the signal oil port 113, that is, the state that the signal oil port 113 is in communication with the rod chamber 13, the rod chamber 13 is connected with the first hydraulic control end 43 and the second hydraulic control end 44 of the second reversing valve 40 (two-position two-way reversing valve) through the second pipeline 16 and the second reversing switching pipeline 221 respectively, at this time, the first hydraulic control end 43 and the second hydraulic control end 44 are equal in pressure, the second reversing valve 40 is in the fourth working position 42 under the action of the first hydraulic control end 43, the second hydraulic control end 44 and the spring, and the first reversing switching pipeline 211 is disconnected; in this state, the pilot port of the first pressure reducing valve 50 is connected with the overflow valve 51, and adjusting the set pressure of the overflow valve 51 can realize the outlet pressure adjustment of the first pressure reducing valve 50, so as to change the pushing force of the piston rod 12 in the pushing stroke.

[0074] As shown, Figure 3 in the pushing stroke of the piston rod 12, when the piston of the piston rod 12 just passes the signal oil port 113, the signal oil port 113 is in communication with the rodless chamber 14, the first hydraulic control end 43 of the second reversing valve 40 is in communication with the rod chamber 13, and the second hydraulic control end 44 of the second reversing valve 40 is in communication with the rodless chamber 14, the high-pressure hydraulic oil in the rodless chamber 14 pushes the first reversing valve 30 to switch from the fourth working position 42 to the third working position 41, and the first reversing switching pipeline 211 switches from the disconnected state to the connected state, so that the high-pressure hydraulic oil of the signal oil port 113 in communication with the rodless chamber 14 enters the first hydraulic control end 33 of the first reversing valve 30 and the damper 61 through the second pressure reducing valve 53 respectively.

[0075] As shown, Figure 4 the high-pressure hydraulic oil entering the first reversing valve 30 pushes the first reversing valve 30 to switch from the first working position 31 to the second working position 32, at this time, the hydraulic oil in the hydraulic pump enters the rod chamber 13 through the second pipeline 16, and the hydraulic oil in the rodless chamber 14 flows out from the oil return port T, the piston rod 12 moves in the direction opposite to the X direction under the action of high-pressure hydraulic oil, and is in the return stroke without load. After the piston of the piston rod 12 in the return stroke passes the signal oil port 113, the pressure in the rod chamber 13 is connected with the first hydraulic control end 43 and the second hydraulic control end 44 of the second reversing valve 40 through the second pipeline 16 and the second reversing switching pipeline 221 respectively, and the pressures of the two are equal, the second reversing valve 40 switches from the third working position 41 to the fourth working position 42 under the action of the first hydraulic control end 43, the second hydraulic control end 44 and the spring, and the first reversing switching pipeline 211 switches from the connected state to the disconnected state.

[0076] When the piston rod 12 is retracted to the appropriate position, the hand control 34 operating the first reversing valve 30 is switched to the first working position 31, and the above process is repeated.

[0077] The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above-described specific embodiments are merely examples of the present application and are not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automatic retracting hydraulic control system for a hydraulic cylinder, comprising: The hydraulic cylinder unit (10) comprises a cylinder barrel (11) and a piston rod (12) capable of reciprocating in the cylinder barrel (11), the cylinder barrel (11) is divided into a rod cavity (13) and a rodless cavity (14) by the piston rod (12), the rodless cavity (14) is connected with a first pipeline (15), and the rod cavity (13) is connected with a second pipeline (16); the control unit (20) comprises a first control pipeline (21) and a signal oil port (113) formed on the cylinder barrel (11), the first control pipeline (21) is connected with the signal oil port (113); in the state that the signal oil port (113) is communicated with the rodless cavity (14), the first control pipeline (21) is configured to adjust the flow direction of the fluid medium flowing through the first pipeline (15) and the fluid medium flowing through the second pipeline (16); the control unit (20) further comprises a second control pipeline (22), the second control pipeline (22) is communicated with the signal oil port (113), and in the state that the signal oil port (113) is communicated with the rod cavity (13), the second control pipeline (22) is configured to cut off the control operation of the first control pipeline (21) on the first pipeline (15) and the second pipeline (16); the first control pipeline (21) comprises a first reversing valve (30) and a first reversing switch pipe (211), the first reversing valve (30) has a first working position (31) capable of pushing the piston rod (12) to extend out of the cylinder barrel (11) and a second working position (32) capable of retracting the piston rod (12) into the cylinder barrel (11); in the state that the fluid medium in the rodless cavity (14) flows into the first reversing switch pipe (211), the first reversing valve (30) can be switched from the first working position (31) to the second working position (32); the first reversing valve (30) has an oil inlet one (P), an oil return port (T), a first oil outlet (A), a second oil outlet (B) and a hydraulic control end (33), the first reversing switch pipe (211) is connected with the hydraulic control end (33) of the first reversing valve (30), the first pipeline (15) and the second pipeline (16) are respectively connected with the first oil outlet (A) of the first reversing valve (30) and the second oil outlet (B) of the first reversing valve (30); in the state that the first reversing valve (30) is in the first working position (31), the fluid medium flows into the rodless cavity (14) of the cylinder barrel (11) through the oil inlet one (P), the first oil outlet (A) and the first pipeline (15), and the fluid medium in the rod cavity (13) of the cylinder barrel (11) flows out of the first reversing valve (30) through the second pipeline (16), the second oil outlet (B) and the oil return port (T). ​ ​ ​ ​ ​ ​ ​ In the state that the first reversing valve (30) is in the second working position (32), the fluid medium flows into the rod cavity (13) of the cylinder barrel (11) through the first oil inlet (P), the second oil outlet (B) and the second pipeline (16), and the fluid medium in the rodless cavity (14) of the cylinder barrel (11) flows out of the first reversing valve (30) through the first pipeline (15), the first oil outlet (A) and the oil return port (T); The second control pipeline (22) comprises a second reversing valve (40) and a second reversing switching pipeline (221), the second reversing valve (40) has a third working position (41) capable of communicating with the first reversing switching pipeline (211) and a fourth working position (42) capable of disconnecting the first reversing switching pipeline (211); In the state that the fluid medium in the rodless cavity (14) flows into the first reversing switching pipeline (211) and the second reversing switching pipeline (221) respectively, the second reversing valve (40) can be switched from the fourth working position (42) to the third working position (41).

2. The hydraulic control system for automatic cylinder return according to claim 1, wherein The second reversing valve (40) has a second oil inlet (C), an oil outlet (D), a first hydraulic control end (43) and a second hydraulic control end (44), the second oil inlet (C) and the oil outlet (D) are located on the first reversing switching pipeline (211), one end of the second reversing switching pipeline (221) is connected with the signal oil port (113), the other end is connected with the second hydraulic control end (44), and the second pipeline (16) is connected with the first hydraulic control end (43).

3. The hydraulic control system for automatic cylinder return according to claim 1, wherein The first pipeline (15) is provided with a first pressure reducing valve (50), and the first pressure reducing valve (50) is connected with an overflow valve (51).

4. The hydraulic control system for automatic cylinder return according to claim 3, wherein The first pipeline (15) is provided with a check valve (52) connected in parallel with the pressure reducing valve.

5. The hydraulic control system for automatic cylinder return according to claim 2, wherein The first reversing switching pipeline (211) is provided with a second pressure reducing valve (53), and the second pressure reducing valve (53) is located between the hydraulic control end (33) of the first reversing valve (30) and the oil outlet (D) of the second reversing valve (40).

6. The hydraulic control system for automatic cylinder return according to claim 5, wherein The hydraulic control end (33) of the first reversing valve (30) is connected with a damping pipeline (60) connected with an oil tank (70), the first reversing switching pipeline (211) is connected with the hydraulic control end (33) of the first reversing valve (30) through the damping pipeline (60), and a damper (61) is arranged on the damping pipeline (60) and located at the downstream end of the first reversing switching pipeline (211).

7. The hydraulic control system for automatic cylinder return of claim 1, wherein, The first reversing valve (30) has a manual control end (34), and the manual control end (34) can switch the first reversing valve (30) from the first working position (31) or the second working position (32) to a non-working position (35) in which the piston rod (12) is in a static state.

8. The hydraulic control system for automatic cylinder return according to claim 7, wherein The first reversing valve (30) is a three-position four-way reversing valve, and the second reversing valve (40) is a two-position two-way reversing valve.

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