Hydraulic system and its stroke limiting and protective device

Abstract

The present invention discloses a hydraulic system and its stroke limiting and protection device, the hydraulic system includes a system hydraulic source, an executing hydraulic cylinder, the executing hydraulic cylinder includes a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod, the executing hydraulic cylinder is used to connect a rotary actuator, the stroke limiting and protection device includes: an extreme position limiting device, the extreme position limiting device includes a stroke limiting valve and a stop check valve, the stroke limiting valve is used to open when the hydraulic cylinder piston rod reaches the extreme position, so that the first hydraulic chamber and the second hydraulic chamber are connected; a speed limiting device, the speed limiting device includes a proximity switch and a stroke limiting signaling valve; a zeroing device, the zeroing device includes a centering valve, a centering function isolation valve, and a centering signal valve. The hydraulic system and stroke limiting and protection device of the present invention can achieve stroke limiting and protection for the executing hydraulic cylinder, as well as necessary automatic control, to meet the diverse needs of the execution end.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic systems and control technology, and in particular to a hydraulic system and a stroke limiting and protecting device thereof. Background Art

[0002] Existing hydraulic systems typically use servo valves to control the flow and velocity of actuator cylinders, controlling the stroke and speed. Pump control can also be used to efficiently control actuator cylinders. However, this also requires emergency response capabilities within the pump or valve control circuits, as well as other necessary automatic control and actuator protection. However, existing hydraulic system circuits cannot meet the diverse control and protection requirements for actuator cylinders. Summary of the Invention

[0003] In response to the above defects or improvement needs of the prior art, the present invention provides a hydraulic system and a stroke limiting and protecting device, which can achieve stroke limiting and protection of the executing hydraulic cylinder, as well as necessary automatic control, to meet the diverse needs of the executing end.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] In some embodiments, a stroke limiting and protective device for a hydraulic system is provided. The hydraulic system includes a system hydraulic source and an actuator hydraulic cylinder. The actuator hydraulic cylinder includes a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod. The actuator hydraulic cylinder is used to connect to a rotary actuator. The stroke limiting and protective device includes:

[0006] An extreme position limiting device, comprising a stroke limiting valve and a stop check valve, wherein both the stroke limiting valve and the stop check valve are provided in pairs, the two stroke limiting valves being installed in the first hydraulic chamber and the second hydraulic chamber respectively, and the two stop check valves being installed between the first hydraulic chamber and the second hydraulic chamber respectively, the stroke limiting valve being used to open when the piston rod of the hydraulic cylinder reaches the extreme position, thereby communicating the first hydraulic chamber with the second hydraulic chamber;

[0007] a speed limiting device, the speed limiting device comprising a proximity switch and a range-limiting signaling valve, the proximity switch being connected to the range-limiting signaling valve, the range-limiting signaling valve being connected to the range-limiting valve, the proximity switch being used to sense the position of the hydraulic cylinder piston rod of the actuator hydraulic cylinder, and controlling the range-limiting signaling valve to open the range-limiting valve when the position of the hydraulic cylinder piston rod reaches a preset position, thereby communicating the first hydraulic chamber with the second hydraulic chamber;

[0008] A zeroing device, the zeroing device includes a centering valve, a centering function isolation valve, and a centering signal valve. The centering valve is connected to the centering signal valve, the centering signal valve is connected to the centering function isolation valve, and the centering valve is connected to the actuator hydraulic cylinder; the centering signal valve is used to open according to the centering signal, so that the pressure oil acts on the centering valve through the centering function isolation valve and the centering signal valve, thereby making the centering valve in zero position.

[0009] In some embodiments, the centering valve includes a main valve, a pull rod spring, a push rod, a roller, and a centering valve striker;

[0010] The centering valve striker is fixedly connected to the piston rod of the hydraulic cylinder, and the centering valve striker has a collision surface, which includes a first height surface, a second height surface, and an inclined surface located between the first height surface and the second height surface, and the first height surface is lower than the second height surface;

[0011] The main valve is a four-position hydraulic valve, and the four positions of the main valve are the initial position, positive position, zero position, and negative position respectively. The negative position end of the main valve has a hydraulic control chamber, and the hydraulic control chamber is connected to the centering signal valve. The pull rod spring is located at the initial position end of the main valve, and the initial position end is connected to the push rod. The end of the push rod is connected to the roller, and the roller is used to abut against the collision surface.

[0012] In some embodiments, there are two limit-stroke signaling valves, one end of each limit-stroke signaling valve is connected to the system hydraulic source, and the other end of each limit-stroke signaling valve is correspondingly connected to a limit-stroke valve.

[0013] In some embodiments, the range limiting valve is a two-position, two-way mechanical hydraulic reversing valve;

[0014] The range-limiting signal valve is a two-position four-way electromagnetic reversing valve;

[0015] The centering isolation valve is a two-position three-way hydraulically controlled directional valve;

[0016] The centering signal valve is a two-position three-way hydraulically controlled reversing valve.

[0017] In some embodiments, the proximity switch is an inductive, capacitive, or Hall-type contactless inductive switch.

[0018] In some embodiments, the stroke limiting and protection device also includes a centering signaling valve, which is connected to the centering signal valve. The centering signaling valve is a two-position three-way electromagnetic reversing valve. The centering signal valve has a hydraulic control chamber, which is connected to the centering signaling valve. The centering signaling valve is connected to the centering functional isolation valve.

[0019] In some embodiments, the stroke limiting and protection device further comprises a cut-off selector valve,

[0020] The cut-off selection valve is used to change the direction of the pressure oil in the hydraulic system under emergency conditions or when the centering signal is turned on, to ensure that the pump control or valve control function of the actuator hydraulic cylinder is removed.

[0021] In some embodiments, the cut-off selection valve is a two-position three-way hydraulic reversing valve having a first hydraulic control chamber and a second hydraulic control chamber, wherein the first hydraulic control chamber is connected to the centering signal valve, and the second hydraulic control chamber is connected to the emergency operation hydraulic source;

[0022] The first port of the cut-off selection valve is connected to the centering signal valve, the second port of the cut-off selection valve is connected to the emergency operation hydraulic source, and the third port of the cut-off selection valve is a control oil port, which is connected to the pump control circuit or valve control circuit of the execution hydraulic cylinder.

[0023] In some embodiments, a hydraulic system is further provided, comprising the stroke limiting and protecting device as described above.

[0024] In some embodiments, the hydraulic system includes: a system hydraulic source, an emergency operation hydraulic source, an electrical control box, and an execution hydraulic cylinder, wherein the execution hydraulic cylinder includes a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod, and the execution hydraulic cylinder is used to connect to a rotary actuator;

[0025] The electrical control box is connected to the centering signaling valve and the range-limiting signaling valve;

[0026] The electrical control box is used to receive the signal from the proximity switch and send a control signal to the range-limiting signal valve according to the signal;

[0027] The electrical control box is used to send a centering signal to the centering signaling valve.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects: through the stroke limiting and protection device, the actuator hydraulic cylinder can achieve stroke limitation and protection, as well as necessary automatic control, to meet the diverse needs of the actuator end. The emergency device can simultaneously control the valve control circuit and the pump control circuit to a closed state through the valve-controlled selector valve and the hydraulic reversing valve, ensuring that the hydraulic automatic control is cut off in an emergency state and ensuring system safety. The technical effects of this application are not limited to the above, and the specific technical effects are further described in detail in the specific implementation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the principle structure of the hydraulic system and the stroke limiting and protection device in some embodiments of the present invention.

[0030] Figure 2 This is a structural block diagram of the hydraulic system and the stroke limiting and protection device in some embodiments of the present invention.

[0031] Figure 3 This is a schematic structural diagram of the centering valve in some embodiments of the present application.

[0032] Figure 4 Schematic diagram of a portion of the structure of the hydraulic system in some embodiments of the present invention. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0034] In the description of the present invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "transverse," "longitudinal," "top," "bottom," "inner," "outer," and "circumferential" and the like, indicating directions or positions, are based on the directions or positions shown in the accompanying drawings. The interpretation of such terms should be based on the perspective of persons skilled in the art.

[0035] In the present invention, unless otherwise expressly defined or limited, terms such as "disposed," "installed," "connected," "connected," and "fixed" should be broadly understood from the perspective of those skilled in the art. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; "connected" may refer to a direct connection or an indirect connection through an intermediate medium, and may refer to internal communication between two elements or an interaction between two elements, unless otherwise expressly defined. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0037] Figure 1Schematic diagram of the principle structure of the hydraulic system in some embodiments of the present invention. Figure 2 This is a structural block diagram of the hydraulic system and the stroke limiting and protection device in some embodiments of the present invention.

[0038] refer to Figure 1 and Figure 2 In some embodiments, the present invention provides a stroke limiting and protective device for a hydraulic system, wherein the hydraulic system includes a system hydraulic source 400 and an actuator hydraulic cylinder 500. The actuator hydraulic cylinder includes a first hydraulic chamber 501, a second hydraulic chamber 502, and a hydraulic cylinder piston rod. The actuator hydraulic cylinder is used to connect to a rotary actuator. The stroke limiting and protective device includes:

[0039] The limit position limiting device 100 includes two limit valves 6 and 7, and two stop check valves 4 and 5. The limit valves and stop check valves are each provided in pairs. The two limit valves are installed in the first and second hydraulic chambers, respectively, and the two stop check valves are installed between the first and second hydraulic chambers. The limit valves are designed to open when the hydraulic cylinder piston rod reaches its limit position, thereby connecting the first and second hydraulic chambers. Specifically, the limit valves include a first limit valve 6 and a second limit valve 7, and the stop check valves include a first stop check valve 4 and a second stop check valve 5. The first limit valve 6 is located in the first hydraulic chamber 501, and the second limit valve 7 is located in the second hydraulic chamber 502. The first stop check valve 4 is located in the pipeline between the first limit valve 6 and the second hydraulic chamber 502. The first stop check valve 4 allows hydraulic oil to flow from the first hydraulic chamber 501 to the second hydraulic chamber 502 while preventing backflow. A second stop-check valve 5 is disposed in the pipeline between the second limit valve 7 and the first hydraulic chamber 501. The second stop-check valve 5 allows hydraulic oil to flow from the second hydraulic chamber 502 to the first hydraulic chamber 501 while preventing backflow. In some embodiments, the first hydraulic chamber 501 and the second hydraulic chamber 502 are connected to a first relief valve 9 and a second relief valve 8, respectively.

[0040] A speed limiting device 200 includes a proximity switch 15 and range-limiting signaling valves 2 and 3. The proximity switch is connected to the range-limiting signaling valve, and the range-limiting signaling valve is connected to the range-limiting valve. The proximity switch is used to sense the position of the hydraulic cylinder piston rod of the actuator hydraulic cylinder. When the position of the hydraulic cylinder piston rod reaches a preset position, the range-limiting signaling valve is controlled to open the range-limiting valve, so that the first hydraulic chamber and the second hydraulic chamber are connected.

[0041] The zeroing device 300 includes a centering valve 10, a centering function isolation valve 11, and a centering signal valve 12. The centering valve is connected to the centering signal valve, which is connected to the centering function isolation valve. The centering valve 10 is connected to the actuator hydraulic cylinder. The centering signal valve 12 is configured to open in response to a centering signal, allowing pressurized oil to flow through the centering function isolation valve 11 and the centering signal valve 12 and act on the centering valve 10, thereby zeroing the centering valve.

[0042] Figure 3 This is a schematic diagram of the structure of the centering valve in some embodiments of the present application. Figure 1 and Figure 3 In some embodiments, the centering valve 10 includes a main valve 101 , a pull rod spring 102 , a push rod 103 , a roller 104 , and a centering valve striker 105 .

[0043] The centering valve striker is fixedly connected to the hydraulic cylinder piston rod, and the centering valve striker has a collision surface, which includes a first height surface 1051, a second height surface 1052 and an inclined surface 1053 located between the first height surface and the second height surface, and the first height surface is lower than the second height surface.

[0044] The main valve is a four-position hydraulic valve, and the four positions of the main valve are the initial position a, the positive position b, the zero position c, and the negative position d. The negative position end of the main valve has a hydraulic control chamber 1011, and the hydraulic control chamber is connected to the centering signal valve 12. The pull rod spring is located at the initial position end of the main valve, and the initial position end is connected to the push rod. The end of the push rod is connected to the roller, and the roller is used to abut against the collision surface.

[0045] Specifically, first elevation surface 1051, second elevation surface 1052, and inclined surface 1053 correspond to negative position d, positive position b, and zero position c, respectively. First elevation surface 1051, second elevation surface 1052, and inclined surface 1053 are used to automatically control the flow direction of hydraulic oil in the two chambers of the actuator hydraulic cylinder based on the position of the piston rod of the actuator hydraulic cylinder.

[0046] In some embodiments, there are two limit-stroke signaling valves, each connected to the system hydraulic source at one end and to a corresponding limit-stroke valve at the other end. Specifically, the limit-stroke signaling valves include a first limit-stroke signaling valve 3 and a second limit-stroke signaling valve 2. The first limit-stroke signaling valve 3 is connected to the first limit-stroke valve 6, and the second limit-stroke signaling valve 2 is connected to the second limit-stroke valve 7. Both the first limit-stroke signaling valve 3 and the second limit-stroke signaling valve 2 are electrically connected to the electrical control box 1.

[0047] In some embodiments, the travel valves 6 and 7 are two-position, two-way, mechanical hydraulic directional valves. Specifically, the hydraulic control chamber of the first travel valve 6 is connected to the first travel signaling valve 3. The hydraulic control chamber of the second travel valve 7 is connected to the second travel signaling valve 2. The hydraulic control chambers of the first and second travel valves 6 and 7 are used for speed control. The mechanical ends of the first and second travel valves 6 and 7 are used to abut against the piston rod for extreme position control.

[0048] In some embodiments, the range limit signaling valves 2 and 3 are two-position, four-way electromagnetic reversing valves. When energized, they are in the connecting position, so that the pressure oil of the system hydraulic source is connected to the first range limit valve 6 or the second range limit valve 7, thereby performing speed limit control.

[0049] In some embodiments, the centering function isolation valve 11 is a two-position three-way hydraulically controlled reversing valve. The hydraulic control chamber of the centering function isolation valve 11 is connected to the P1 port of the emergency operation hydraulic source. During the zeroing operation, the centering function isolation valve 11 is in the connected position ( Figure 1 In the emergency operation condition, the pressure oil of the emergency operation hydraulic source P1 port acts on the hydraulic control chamber of the centering function isolation valve 11, making it in the cut-off position ( Figure 1 Center left position), cut off the pressure oil of the system hydraulic source through the centering function isolation valve 11.

[0050] In some embodiments, the centering signal valve 12 is a two-position three-way hydraulically controlled reversing valve. In some embodiments, the stroke limiting and protection device further includes a centering signaling valve 14, which is connected to the centering signal valve 12. The centering signaling valve 14 is a two-position three-way electromagnetic reversing valve. The centering signal valve 12 has a hydraulic control chamber. The hydraulic control chamber of the centering signal valve 12 is connected to the centering signaling valve 14, and the centering signaling valve 14 is connected to the centering functional isolation valve 11. During the zeroing operation, the electrical control box 1 sends a centering signal, the centering signaling valve 14 is energized, the centering signaling valve 14 is in the connected position, and the pressure oil of the centering functional isolation valve 11 passes through the centering signaling valve 14 to reach the hydraulic control chamber of the centering signal valve 12, so that the centering signal valve 12 is in the connected position ( Figure 1 The pressure oil is able to pass through the centering signal valve 12 to the Ps port of the main valve 101.

[0051] In some embodiments, the proximity switch 15 is an inductive, capacitive, or Hall-type contactless inductive switch.

[0052] In some embodiments, the stroke limiting and protection device also includes a cut-off selection valve 13, which is used to change the direction of the pressure oil of the hydraulic system in an emergency condition or when the centering signal is turned on to ensure that the pump control or valve control function of the executing hydraulic cylinder is removed.

[0053] In some embodiments, the cut-off selection valve 13 is a two-position three-way hydraulic reversing valve having a first hydraulic control chamber and a second hydraulic control chamber. The first hydraulic control chamber is connected to the centering signal valve 12, and the second hydraulic control chamber is connected to the emergency operation hydraulic source.

[0054] The first port of the cut-off selection valve is connected to the centering signal valve, the second port of the cut-off selection valve is connected to the emergency operation hydraulic source, and the third port of the cut-off selection valve is a control oil port, which is connected to the pump control circuit or valve control circuit of the execution hydraulic cylinder.

[0055] Some embodiments of the present invention further provide a hydraulic system, which includes the stroke limiting and protecting device as described above.

[0056] In some embodiments, the hydraulic system includes: a system hydraulic source 400, an emergency operation hydraulic source 600, an electrical control box 1, and an actuator hydraulic cylinder 500. The actuator hydraulic cylinder includes a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod. The actuator hydraulic cylinder is used to connect to a rotary actuator.

[0057] The electrical control box 1 is connected to the centering signaling valve 14 and the range-limiting signaling valves 2 and 3;

[0058] The electrical control box 1 is used to receive the signal from the proximity switch 15 and send a control signal to the range-limiting signal valves 2 and 3 according to the signal;

[0059] The electrical control box 1 is used to send a centering signal to the centering signaling valve 14 .

[0060] The working principles of the hydraulic system and the stroke limiting and protection device in some embodiments of the present application are as follows.

[0061] (1) Working principle of extreme position limitation

[0062] The limit position limit is achieved by restricting the unidirectional movement of the piston rod of the actuator hydraulic cylinder. When the piston rod reaches the limit position, the safety protection device will prevent it from moving in the direction of increase, and only allow it to move in the direction of decrease. Normal bidirectional drive can only be resumed when the piston rod leaves the limit position in the opposite direction.

[0063] During normal operation, the limit valves 6 and 7 are in the closed state and can be driven normally in both directions. Figure 1 When the piston rod moves to the right to the limit position (i.e. the maximum limit position), the piston hits the valve core of the travel limit valve 6, opening the valve. The second hydraulic chamber of the actuator hydraulic cylinder is connected to the right chamber through the stop check valve and the travel limit valve. The pressure oil cannot form an effective pressure difference between the left and right chambers, and the piston rod cannot continue to move to the right. At this time, if the left operation is performed, the pressure oil enters the first hydraulic chamber of the actuator hydraulic cylinder ( Figure 1 In the middle right chamber, the oil in the first hydraulic chamber cannot pass through the stroke-limiting valve to the second hydraulic chamber due to the non-return function of stop-check valve 4. This allows the oil to create a normal operating pressure differential between the left and right chambers, pushing the piston leftward. After the piston leaves its maximum limit position, the spring in stroke-limiting valve 6 returns the spool, closing it. At this point, the two chambers of the actuator hydraulic cylinder are completely isolated, enabling normal bidirectional operation.

[0064] (2) Working principle of speed limit

[0065] The position of proximity switch 15 corresponds to the speed limit position, which in turn corresponds to the actual speed of the end-rotation actuator. If the piston rod of the actual actuator reaches the speed limit position, proximity switch 15 sends a position signal to the electrical control box. The speed limit function can be manually selected to be enabled or disabled. When "enabled," the control program evaluates the speed signal received from the end-rotation actuator. If the speed reaches the set speed limit value, the electrical control box, upon receiving the position signal from proximity switch 15, commands limit valves 2 and 3 to open limit valves 7 and 6, thereby bypassing the left and right chambers of the actuator. Similar to the operating principle of the extreme position limit, the actuator cylinder can only be operated in one direction, toward the direction of stroke reduction. After the piston rod of the actuator cylinder reverses its motion and leaves the limit position, the limit valve closes, allowing normal bidirectional drive operation.

[0066] (3) One-key reset working principle

[0067] refer to Figure 3 The centering valve 10 is the core component for achieving one-touch zeroing. Ports A and B of the centering valve 10 connect to the two chambers of the actuator hydraulic cylinder, respectively; port O of the centering valve connects to the return oil. During normal operation, no pressure oil enters port Ps. The main valve is in position a, disconnected from the two chambers of the actuator hydraulic cylinder by the pull rod spring, and the roller and push rod retract. When the operating instrument loses power or issues a one-touch zeroing command, the centering signal valve 12 opens, and pressurized oil from the hydraulic system's hydraulic source flows through the centering function isolation valve 11 and the centering signal valve 12 to port Ps. This hydraulic force overcomes the pull rod spring, depressing the push rod and roller downward. The specific depression position is determined by the relative position of the roller and the centering valve striker. When the roller presses against the second elevation surface 1052 of the centering valve striker, the main valve is in position b. The second hydraulic chamber of the actuator hydraulic cylinder connected to port A receives pressurized oil, while the first hydraulic chamber connected to port B receives return oil, causing the rotary actuator to move from the positive direction to the zero direction. When the roller presses against the second-highest surface 1051 of the centering valve striker, the main valve is in position d. The first hydraulic chamber connected to port B receives pressurized oil, while the second hydraulic chamber of the actuator hydraulic cylinder connected to port A receives return oil, causing the rotary actuator to move from the negative direction toward zero degrees. When the roller stops at a point on the inclined surface 1053 of the centering valve striker, the main valve is in position c, and the rotary actuator is now in zero position.

[0068] The control port of the centering function isolation valve 11 is connected to the control oil port P1 of the emergency device. It is opened during normal operation and closed during emergency operation to ensure that the centering function is automatically removed during emergency operation.

[0069] Under the emergency operation condition of the hydraulic system, the cut-off selection valve 13 will pass the pressure oil at the control oil port P1 of the emergency device to the hydraulic system circuit conversion control oil port P2, ensuring that the pump control or valve control function is removed during emergency operation; when the one-button zeroing function is put into use, the cut-off selection valve 13 will pass the pressure oil at the system hydraulic source of the hydraulic system to the hydraulic system circuit conversion control oil port P2, ensuring that the pump control or valve control function is removed when the one-button zeroing function is put into use.

[0070] refer to Figure 4 In some embodiments, the hydraulic system further comprises: a pump-valve conversion device, a pump-controlled circuit device, and a valve-controlled circuit device. The pump-controlled circuit device comprises a pump-controlled circuit; the valve-controlled circuit device comprises a valve-controlled circuit. The pump-valve conversion device connects the pump-controlled circuit device and the valve-controlled circuit device.

[0071] The pump-valve conversion device includes a pump-valve conversion valve 601, and the pump-valve conversion valve 601 has a pump control position ( Figure 4 As shown) and valve control position, the pump-valve conversion valve 601 is used to control the hydraulic system to convert between the pump control circuit and the valve control circuit.

[0072] The pump control circuit device includes a pump control driving source, a hydraulically controlled reversing valve 609, and a pump control main valve 608. The pump control driving source includes a first port A11, a second port B11, and a third port K. The first port A11 and the second port B11 of the pump control driving source are connected to the pump control main valve 608. The pump control main valve 608 is connected to the pump valve conversion valve 601. The pump valve conversion valve 601 is connected to the actuator hydraulic cylinder (not shown). Figure 4 Ports A01 and B01 are connected to the two hydraulic chambers of the actuator hydraulic cylinder), and the third port K of the pump-controlled drive source is connected to the hydraulically controlled reversing valve 609, which is connected to the pump-controlled main valve 608. In some embodiments, the pump-controlled main valve 608 is a two-position four-way hydraulic reversing valve.

[0073] The valve-controlled circuit device includes a valve-controlled hydraulic source and a servo valve. The valve-controlled hydraulic source is connected to the servo valve, and the servo valve is connected to the pump-valve conversion valve 601 .

[0074] The emergency device is connected to the valve control circuit and the pump control circuit, and is used to cut off the valve control circuit and the pump control circuit.

[0075] In an embodiment of the present application, the hydraulic system is controlled by a pump-valve conversion valve to switch between the pump-controlled circuit and the valve-controlled circuit. The emergency device can simultaneously cut off the valve-controlled circuit and the pump-controlled circuit in an emergency, and the overall system switching is convenient and reliable.

[0076] In some embodiments, the emergency device includes an emergency hydraulic source, a valve-controlled selection valve 602 , a hydraulic reversing valve 610 , and a relief valve 611 .

[0077] The emergency hydraulic source is connected to the valve-controlled selection valve 602, one end of the valve-controlled selection valve 602 is connected to the pump-valve conversion valve 601, and the other end is connected to the servo valve. The valve-controlled selection valve 602 is used to cut off the valve-controlled circuit under the pressure of the emergency hydraulic source.

[0078] The emergency hydraulic source is connected to the hydraulic reversing valve 610, and the hydraulic reversing valve 610 is connected to the pump-controlled main valve 608. The hydraulic reversing valve 610 is used to form an emergency hydraulic source passage under the pressure of the emergency hydraulic source, so that the pressure of the emergency hydraulic source acts on the pump-controlled main valve 608, causing the pump-controlled main valve 608 to switch from the working position to the bypass position, thereby bypassing the first port A11 and the second port B11 of the pump-controlled driving source;

[0079] The hydraulic reversing valve 610 is also connected to the hydraulically controlled reversing valve 609, and the hydraulically controlled reversing valve 609 is connected to the overflow valve 611. The hydraulic reversing valve 610 is used to form an emergency hydraulic source passage under the pressure of the emergency hydraulic source, so that the pressure of the emergency hydraulic source acts on the hydraulically controlled reversing valve 609, so that the hydraulically controlled reversing valve 609 switches from the connecting position to the blocking position, so that the pressure oil of the third port of the pump-controlled drive source reaches the overflow valve, so that the overflow valve is in a connecting state.

[0080] In the embodiment of the present application, the emergency device can simultaneously control the valve control circuit and the pump control circuit to be in the cut-off state through the valve control selection valve 602 and the hydraulic reversing valve 610, ensuring that the hydraulic automatic control is cut off in the emergency state to ensure system safety.

[0081] In some embodiments, the emergency hydraulic source is Figure 4 The emergency hydraulic source port K01 is connected to the hydraulic system circuit switching control port P2. The emergency hydraulic source is connected to a safety protection device. When the safety protection device is activated, the emergency hydraulic source activates, and pressurized oil is generated at the emergency hydraulic source port K01. In some embodiments, the safety protection device is a device that, in an emergency, cuts off the driving pressure oil of the pump control circuit and valve control circuit of the actuator hydraulic cylinder, thereby achieving safety protection for the actuator hydraulic cylinder. In some embodiments, the safety protection device is an emergency manual mechanism or an automatically triggered sensor mechanism.

[0082] In some embodiments, the valve-controlled circuit device includes a first electromagnetic reversing valve 605 and a hydraulically controlled one-way valve 612. The hydraulically controlled one-way valve 612 is arranged between the first port P11 of the valve-controlled hydraulic source and the servo valve; the first port P11 of the valve-controlled hydraulic source is an oil outlet.

[0083] One end of the first electromagnetic reversing valve 605 is connected to the first port P11 of the valve-controlled hydraulic source, and the other end is connected to the hydraulic reversing valve 610 , the hydraulically controlled one-way valve 612 , and the pump-valve conversion valve 601 .

[0084] When the first electromagnetic reversing valve 605 is in the electric potential, the first port P11 of the valve-controlled hydraulic source is in a connected state with the hydraulically controlled one-way valve 612, the pump-valve conversion valve 601, and the hydraulic reversing valve 610 through the first electromagnetic reversing valve 605, so that the oil outlet P11 of the valve-controlled hydraulic source is connected with the servo valve, the pump-valve conversion valve 601 is in the valve-controlled position, and the hydraulic reversing valve 610 forms a valve-controlled hydraulic source passage and acts on the pump-controlled main valve 608 and the hydraulically controlled reversing valve 609.

[0085] When the first electromagnetic reversing valve 605 is de-energized, the first port P11 of the valve-controlled hydraulic source and the hydraulically controlled one-way valve 612, the pump-valve conversion valve 601, and the hydraulic reversing valve 610 are all in a cut-off state, and the valve-controlled circuit is in a disconnected state.

[0086] Specifically, in some embodiments, the pump-valve conversion valve 601 is a two-position six-way hydraulic reversing valve having a pump control position and a valve control position. The six ports of the pump-valve conversion valve 601 are respectively connected to the first port A11 and the second port B11 of the pump-controlled hydraulic source, the first port P11 and the second port T11 of the valve-controlled hydraulic source, and the first port A11 and the second port B11 of the driving hydraulic cylinder. Among them, the first port P11 and the second port T11 of the valve-controlled hydraulic source are the oil outlet and the oil return port, respectively. The first port A11 and the second port B11 of the driving hydraulic cylinder are respectively connected to the two hydraulic oil chambers of the driving hydraulic cylinder, and the driving hydraulic cylinder is a single-rod double-drive hydraulic cylinder. The first port A11 and the second port B11 of the pump-controlled hydraulic source can be used as the oil inlet and the oil return port, respectively.

[0087] In some embodiments, the pump-controlled main valve 608 is a two-position, four-way hydraulic reversing valve. It has a connecting position and a blocking position. It has a first hydraulic chamber and a second hydraulic chamber. The first hydraulic chamber of the pump-controlled main valve 608 is connected to the hydraulic reversing valve 609, while the second hydraulic chamber of the pump-controlled main valve 608 is connected to the hydraulic reversing valve 610. In the connecting position, the first port A11 and the second port B11 of the pump-controlled hydraulic source are connected to the pump-controlled main valve 608, enabling reversal of flow.

[0088] The hydraulic reversing valve 610 is a two-position, three-way hydraulic reversing valve. It has a control position and an emergency position. It has a first hydraulic chamber and a second hydraulic chamber. The first hydraulic chamber of the hydraulic reversing valve 610 is connected to the first solenoid reversing valve 605, while the second hydraulic chamber of the hydraulic reversing valve 610 is connected to the emergency hydraulic source port K01.

[0089] In some embodiments, the servo valve includes a first servo valve 603 and a second servo valve 604, and the valve-controlled circuit device also includes a servo valve conversion valve 607, one end of the servo valve conversion valve 607 is connected to the first servo valve 603 and the second servo valve 604, and the other end is connected to the valve-controlled selection valve 602.

[0090] The valve-controlled circuit device further includes a second electromagnetic reversing valve 606 , which is connected to the servo valve conversion valve 607 . The second electromagnetic reversing valve 606 is used to control the servo valve conversion valve 607 to switch the connection between the first servo valve 603 and the second servo valve 604 .

[0091] In some embodiments, one end of the second solenoid reversing valve 606 is connected to the first port P11 of the valve-controlled hydraulic source, and the other end is connected to the servo-valve switching valve 607. In some embodiments, the servo-valve switching valve 607 is a two-position, six-way hydraulic reversing valve having a first hydraulic chamber and a second hydraulic chamber. The first hydraulic chamber of the servo-valve switching valve 607 is connected to the second solenoid reversing valve 606, and the second hydraulic chamber is connected to the oil return port T11 of the valve-controlled hydraulic source.

[0092] When the second solenoid reversing valve 606 is at the set potential, the second solenoid reversing valve 606 transmits the hydraulic force of the valve-controlled hydraulic source to the servo valve conversion valve 607. Under the action of the hydraulic force, the servo valve conversion valve 607 is in the second working position and is connected to the second servo valve 604, and is cut off from the first servo valve 603, thereby realizing the conversion connection from the first servo valve 603 to the second servo valve 604.

[0093] In an embodiment of the present application, the first servo valve 603 can serve as the main servo valve, and the second servo valve 604 can serve as the backup servo valve. The servo valve conversion valve 607 is used to switch the connection between the first servo valve 603 and the second servo valve 604, so that the valve control circuit can realize the mutual conversion between the main and backup servo valves, realize redundant design, and be more reliable.

[0094] In some embodiments, both the first solenoid reversing valve 605 and the second solenoid reversing valve 606 are two-position, four-way solenoid reversing valves. Both the first solenoid reversing valve 605 and the second solenoid reversing valve 606 can be connected to the oil unloading port X. In the embodiment of the present application, control of the valve control circuit and switching between the primary and backup servo valves are achieved by energizing and de-energizing the first and second solenoid reversing valves 605 and 606 to control the valve control circuit and connecting and disconnecting the servo valve switching valve 607 to the first and second servo valves 603 and 604.

[0095] In some embodiments, the hydraulic system includes a valve-controlled damping element, wherein the valve-controlled damping element includes a first valve-controlled damping element (not directly shown in the figure, Figure 4 connected to port C) and a second valve-controlled damping element (not directly shown, Figure 4 Connected to port D).

[0096] The first valve-controlled vibration damping element is connected between the first port P11 of the valve-controlled hydraulic source and the servo valve.

[0097] The second valve-controlled damping element is connected between the second port T11 of the valve-controlled hydraulic source and the servo valve, and is connected between the servo valve conversion valve 607 and the valve-controlled selector valve 602 .

[0098] In some embodiments, the hydraulic system includes a safety valve, which is a relief valve 611. The relief valve is a safety valve of the hydraulic system, which plays a protective role when the control oil pressure is too high, and its set pressure can be 2.5 MPa.

[0099] When the emergency manual operating mechanism is pulled out or the automatic trigger sensor mechanism of the hydraulic cylinder safety protection device is started, the pressure oil at the K01 port on the hydraulic system of the hydraulic cylinder and pump valve combination operation reaches 8MPa-10MPa. At this time, under the action of the pressure oil, the valve control selector valve 602 switches to the cut-off state ( Figure 4 The valve control circuit is cut off. At the same time, the pressure oil at port K01 acts on the second hydraulic chamber of the pump control main valve 608. The pump control main valve 608 is in the bypass position ( Figure 4 In addition, the pressure oil at port K01 acts on the second hydraulic chamber of the hydraulic control reversing valve 609, and the hydraulic control reversing valve 609 is in the cut-off position ( Figure 4 The pump control circuit is cut off.

[0100] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A stroke limiting and protecting device for a hydraulic system, characterized in that: The hydraulic system includes a system hydraulic source, an actuator hydraulic cylinder, the actuator hydraulic cylinder includes a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod, the actuator hydraulic cylinder is used to connect to the rotary actuator, and the stroke limiting and protection device includes: An extreme position limiting device, comprising a stroke limiting valve and a stop check valve, wherein both the stroke limiting valve and the stop check valve are provided in pairs, the two stroke limiting valves being installed in the first hydraulic chamber and the second hydraulic chamber respectively, and the two stop check valves being installed between the first hydraulic chamber and the second hydraulic chamber respectively, the stroke limiting valve being used to open when the piston rod of the hydraulic cylinder reaches the extreme position, thereby communicating the first hydraulic chamber with the second hydraulic chamber; A speed limiting device, comprising a proximity switch (15) and a range-limiting signaling valve, wherein the proximity switch is connected to the range-limiting signaling valve, and the range-limiting signaling valve is connected to the range-limiting valve, wherein the proximity switch is used to sense the position of the hydraulic cylinder piston rod of the actuator hydraulic cylinder, and when the position of the hydraulic cylinder piston rod reaches a preset position, the range-limiting signaling valve is controlled to open the range-limiting valve, so that the first hydraulic chamber and the second hydraulic chamber are connected; A zeroing device, the zeroing device comprising a centering valve (10), a centering function isolation valve (11), and a centering signal valve (12), wherein the centering valve is connected to the centering signal valve, the centering signal valve is connected to the centering function isolation valve, and the centering valve (10) is connected to the actuator hydraulic cylinder; the centering signal valve (12) is used to open according to a centering signal, so that pressure oil acts on the centering valve (10) through the centering function isolation valve (11) and the centering signal valve (12), thereby placing the centering valve in a zero position; The centering valve includes a main valve, a pull rod spring, a push rod, a roller, and a centering valve striker; The centering valve striker is fixedly connected to the piston rod of the hydraulic cylinder, and the centering valve striker has a collision surface, which includes a first height surface, a second height surface, and an inclined surface located between the first height surface and the second height surface, and the first height surface is lower than the second height surface; The main valve is a four-position hydraulic valve, and the four positions of the main valve are the initial position, the positive position, the zero position, and the negative position, respectively. The negative position end of the main valve has a hydraulic control chamber, and the hydraulic control chamber is connected to the centering signal valve (12). The pull rod spring is located at the initial position end of the main valve, and the initial position end is connected to the push rod. The end of the push rod is connected to the roller, and the roller is used to abut against the collision surface.

2. The stroke limiting and protecting device of the hydraulic system according to claim 1, characterized in that: There are two limit-stroke signaling valves, one end of each limit-stroke signaling valve is connected to the system hydraulic source, and the other end of each limit-stroke signaling valve is correspondingly connected to a limit-stroke valve.

3. The stroke limiting and protecting device for a hydraulic system according to claim 2, characterized in that: The range limiting valve is a two-position, two-way mechanical hydraulic reversing valve; The range-limiting signal valve is a two-position four-way electromagnetic reversing valve; The centering function isolation valve (11) is a two-position three-way hydraulically controlled reversing valve; The centering signal valve (12) is a two-position three-way hydraulically controlled directional valve.

4. The stroke limiting and protecting device for a hydraulic system according to claim 3, characterized in that: The proximity switch is one of an inductive, capacitive, or Hall-type contactless inductive switch.

5. The stroke limiting and protecting device for a hydraulic system according to claim 4, characterized in that: The stroke limiting and protection device also includes a centering signaling valve (14), which is connected to the centering signaling valve (12). The centering signaling valve is a two-position three-way electromagnetic reversing valve. The centering signaling valve (12) has a hydraulic control chamber, which is connected to the centering signaling valve, and the centering signaling valve is connected to the centering functional isolation valve (11).

6. The stroke limiting and protecting device for a hydraulic system according to claim 5, characterized in that: The stroke limiting and protection device also includes a cut-off selection valve (13), The cut-off selection valve is used to change the direction of the pressure oil in the hydraulic system under emergency conditions or when the centering signal is turned on, to ensure that the pump control or valve control function of the actuator hydraulic cylinder is removed.

7. The stroke limiting and protecting device for a hydraulic system according to claim 6, characterized in that: The cut-off selection valve is a two-position three-way hydraulic reversing valve having a first hydraulic control chamber and a second hydraulic control chamber, wherein the first hydraulic control chamber is connected to the centering signal valve (12), and the second hydraulic control chamber is connected to the emergency operation hydraulic source; The first port of the cut-off selection valve is connected to the centering signal valve, the second port of the cut-off selection valve is connected to the emergency operation hydraulic source, and the third port of the cut-off selection valve is a control oil port, which is connected to the pump control circuit or valve control circuit of the execution hydraulic cylinder.

8. A hydraulic system, characterized in that: The hydraulic system includes the stroke limiting and protection device according to claim 7.

9. The hydraulic system according to claim 8, characterized in that The hydraulic system includes: a system hydraulic source, an emergency operation hydraulic source, an electrical control box, and an execution hydraulic cylinder. The execution hydraulic cylinder includes a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod. The execution hydraulic cylinder is used to connect to a rotary actuator. The electrical control box is connected to the centering signaling valve (14) and the range-limiting signaling valve; The electrical control box is used to receive the signal from the proximity switch and send a control signal to the range-limiting signal valve according to the signal; The electrical control box is used to send a centering signal to a centering signal sending valve (14).

10. The hydraulic system according to claim 9, characterized in that The hydraulic system includes: a pump-valve conversion device, a pump control circuit device, a valve control circuit device, and an emergency device; The pump control circuit device has a pump control circuit; the valve control circuit device has a valve control circuit; the pump-valve conversion device connects the pump control circuit device and the valve control circuit device; The emergency device is connected to the valve control circuit and the pump control circuit, and is used to cut off the valve control circuit and the pump control circuit.

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