Hydraulic system and stroke limiting and protecting device thereof

Abstract

The invention discloses a hydraulic system and a stroke limiting and protecting device thereof.The hydraulic system comprises a system hydraulic source and an execution hydraulic cylinder, the execution hydraulic cylinder comprises a first hydraulic cavity, a second hydraulic cavity and a hydraulic cylinder piston rod, and the execution hydraulic cylinder is used for being connected with a rotary execution mechanism; the stroke limiting and protecting device comprises an extreme position limiting device, the extreme position limiting device comprises a stroke limiting valve and a stop check valve, and the stroke limiting valve is used for being opened when a piston rod of the hydraulic cylinder reaches an extreme position, so that a first hydraulic cavity is communicated with a second hydraulic cavity; the speed limiting device comprises a proximity switch and a range limiting signaling valve; and the zeroing device comprises a centering valve, a centering function isolation valve and a centering signal valve. According to the hydraulic system and the stroke limiting and protecting device, stroke limiting and protecting and necessary automatic control of the execution hydraulic cylinder can be achieved, and the diversified requirements of an execution tail end are met.

Description

Technical Field

[0001] The 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 generally use servo valves to control the flow and flow rate of the hydraulic cylinder to control the stroke and speed. There are also pump controls to efficiently control the hydraulic cylinder. However, it is also necessary to respond to emergencies in the pump control circuit or valve control circuit, as well as other necessary automatic control and protection. However, the existing hydraulic system circuits cannot meet the diverse control and protection requirements of the hydraulic cylinder. Summary of the invention

[0003] In view of 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 realize stroke limiting and protection of the actuator hydraulic cylinder, as well as necessary automatic control to meet the diverse needs of the actuator 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 protecting device for a hydraulic system is provided, wherein the hydraulic system comprises a system hydraulic source and an executing hydraulic cylinder, wherein the executing hydraulic cylinder comprises a first hydraulic chamber, a second hydraulic chamber, and a hydraulic cylinder piston rod, wherein the executing hydraulic cylinder is used to connect a rotary actuator, and wherein the stroke limiting and protecting device comprises:

[0006] The limit position limiting device comprises a stroke limiting valve and a stop check valve, wherein the stroke limiting valve and the stop check valve are both provided with two stroke limiting valves, the two stroke limiting valves are respectively installed in the first hydraulic chamber and the second hydraulic chamber, and the two stop check valves are respectively installed between the first hydraulic chamber and the second hydraulic chamber, and the stroke limiting valve is used to open when the piston rod of the hydraulic cylinder reaches the limit position, so that the first hydraulic chamber and the second hydraulic chamber are connected;

[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 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;

[0008] A zeroing device, the zeroing device includes a centering valve, a centering functional 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 functional isolation valve, and the centering valve is connected to the actuator hydraulic cylinder; the centering signal valve is used to open according to a centering signal, so that the pressure oil acts on the centering valve through the centering functional isolation valve and the centering signal valve, thereby making the centering valve in the 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, and the collision surface 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 travel limiting valve is a two-position, two-way mechanical hydraulic reversing valve;

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

[0015] The centering function isolation valve is a two-position three-way hydraulically controlled reversing 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 induction 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 travel 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 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 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 actuator hydraulic cylinder.

[0023] In some embodiments, a hydraulic system is also provided, the hydraulic system 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 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 of the proximity switch and send a control signal to the limit-range signal-transmitting valve according to the signal;

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

[0028] Compared with the prior art, the beneficial effects of the present invention are at least that: through the stroke limiting and protection device, the stroke limiting and protection of the actuator hydraulic cylinder, as well as the necessary automatic control, can be achieved 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 be in the cut-off state through the valve-controlled selection valve and the hydraulic reversing valve, ensuring that the hydraulic automatic control is cut off in the emergency state to ensure system safety. The technical effects of this application are not limited to the above examples, and the specific technical effects are described in detail in the specific implementation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the principle structure of the hydraulic system and the stroke limiting and protecting device in some embodiments of the present invention.

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

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

[0032] Figure 4 It is a partial structural schematic diagram of the hydraulic system in some embodiments of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain 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 can 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", "back", "left", "right", "vertical", "horizontal", "lateral", "longitudinal", "top", "bottom", "inner", "outer", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings. The interpretation of such terms should be conducted from the perspective of those skilled in the art.

[0035] In the present invention, unless otherwise clearly defined and specified, the terms "set", "install", "connect", "connect", "fix" and the like should be understood in a broad sense from the perspective of those skilled in the art. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0036] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0037] Figure 1It is a schematic diagram of the principle structure of the hydraulic system in some embodiments of the present invention. Figure 2 It is a structural block diagram of the hydraulic system and the stroke limiting and protecting 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 protecting device for a hydraulic system, wherein the hydraulic system comprises a system hydraulic source 400, an executing hydraulic cylinder 500, the executing hydraulic cylinder comprises a first hydraulic chamber 501, a second hydraulic chamber 502, and a hydraulic cylinder piston rod, the executing hydraulic cylinder is used to connect a rotary actuator, and the stroke limiting and protecting device comprises:

[0039] The limit position limiting device 100 includes a travel limiting valve 6, 7, and a stop check valve 4, 5. The travel limiting valve and the stop check valve are both provided with two, and the two travel limiting valves are respectively installed in the first hydraulic chamber and the second hydraulic chamber, and the two stop check valves are respectively installed between the first hydraulic chamber and the second hydraulic chamber. The travel limiting valve is used to open when the piston rod of the hydraulic cylinder reaches the limit position, so that the first hydraulic chamber and the second hydraulic chamber are connected. Specifically, the travel limiting valve includes a first travel limiting valve 6 and a second travel limiting valve 7, and the stop check valve includes a first stop check valve 4 and a second stop check valve 5. The first travel limiting valve 6 is arranged in the first hydraulic chamber 501, and the second travel limiting valve 7 is arranged in the second hydraulic chamber 502. The first stop check valve 4 is arranged on the pipeline between the first travel limiting valve 6 and the second hydraulic chamber 502, and the first stop check valve 4 allows the hydraulic oil to flow from the first hydraulic chamber 501 to the second hydraulic chamber 502 to prevent backflow. The second stop check valve 5 is disposed on the pipeline between the second limit valve 7 and the first hydraulic chamber 501. The second stop check valve 5 allows the hydraulic oil to flow from the second hydraulic chamber 502 to the first hydraulic chamber 501 and prevents backflow. In some embodiments, the first hydraulic chamber 501 and the second hydraulic chamber 502 are connected to the first overflow valve 9 and the second overflow valve 8, respectively.

[0040] A speed limiting device 200, which includes a proximity switch 15, a range-limiting signaling valve 2 and a range-limiting signaling valve 3, 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. 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, 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 the centering signal, so that the pressure oil acts on the centering valve 10 through the centering function isolation valve 11 and the centering signal valve 12, so that the centering valve is in the zero position.

[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 respectively 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, the first height surface 1051, the second height surface 1052 and the inclined surface 1053 correspond to the negative position d, the positive position b and the zero position c respectively. The first height surface 1051, the second height surface 1052 and the inclined surface 1053 are used to automatically control the flow direction of the hydraulic oil in the two chambers of the actuator hydraulic cylinder according to the piston rod position of the actuator hydraulic cylinder.

[0046] In some embodiments, the travel-limited signaling valve has two, each of which has one end connected to the system hydraulic source, and the other end of each travel-limited signaling valve is correspondingly connected to a travel-limited valve. Specifically, the travel-limited signaling valve includes a first travel-limited signaling valve 3 and a second travel-limited signaling valve 2. The first travel-limited signaling valve 3 is connected to the first travel-limited valve 6, and the second travel-limited signaling valve 2 is connected to the second travel-limited valve 7. The first travel-limited signaling valve 3 and the second travel-limited signaling valve 2 are both electrically connected to the electrical control box 1.

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

[0048] In some embodiments, the range limiting signaling valves 2 and 3 are two-position four-way electromagnetic reversing valves. When powered, they are in the connecting position, so that the pressure oil of the system hydraulic source is connected to the first range limiting valve 6 or the second range limiting valve 7, thereby performing speed limiting 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 at port P1 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 protecting device further comprises a centering signaling valve 14, the centering signaling valve 14 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 can reach the Ps port of the main valve 101 through the centering signal valve 12.

[0051] In some embodiments, the proximity switch 15 is an inductive, capacitive, or Hall-type contactless induction 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 actuator 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 actuator 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 execution hydraulic cylinder 500, 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 a rotary actuator;

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

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

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

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

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

[0062] The limit position limit is achieved by limiting 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; when the piston rod leaves the limit position in the reverse direction, it can resume normal bidirectional drive.

[0063] In normal operation, the travel 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 to open 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 Due to the check function of the stop check valve 4, the pressure oil in the first hydraulic chamber cannot reach the second hydraulic chamber through the limit valve. The pressure oil can form a normal operating pressure difference between the left and right chambers to push the piston to the left. After the piston leaves the maximum limit position, the valve core of the limit valve 6 is reset under the action of the spring, so that the limit valve 6 is closed. At this time, the two chambers of the executive hydraulic cylinder are completely isolated and can be operated normally in both directions.

[0064] (II) Working principle of speed limit

[0065] The position of the proximity switch 15 corresponds to the speed limit position, and the speed limit position corresponds to the actual speed of the end rotary actuator. If the piston rod of the actual execution hydraulic cylinder reaches the speed limit position, the proximity switch 15 sends a position signal to the electrical control box. Manually select the activation / removal of the speed limit function. When "activation" is selected, the control program judges the speed signal received from the end rotary actuator. If the speed reaches the set value of the speed limit, the electrical control box receives the position signal sent by the proximity switch 15, and then commands the limit valves 2 and 3 to open the limit valves 7 and 6, and the left and right chambers of the execution hydraulic cylinder are bypassed in one direction. Similar to the working principle of the extreme position limit, the execution hydraulic cylinder can only be operated in one direction in the direction of stroke reduction. After the piston rod of the execution hydraulic cylinder moves in the opposite direction to leave the limit position, the limit valve is closed, and normal bidirectional drive operation can be carried out.

[0066] (III) Working principle of one-key reset

[0067] refer to Figure 3 , the centering valve 10 is the core component for completing one-button zeroing. The A and B ports of the centering valve 10 are connected to the two chambers of the actuator hydraulic cylinder respectively; the O port of the centering valve is connected to the return oil; during normal operation, no pressure oil enters the Ps port. Under the action of the pull rod spring, the main valve is in position a. At this time, the centering valve is disconnected from the two chambers of the actuator hydraulic cylinder, and the roller and the push rod are retracted. When the operator loses power or issues a one-button zeroing action command, the centering signal valve 12 opens, and the pressure oil of the system hydraulic source of the hydraulic system flows into the Ps port through the centering function isolation valve 11 and the centering signal valve 12. The hydraulic force overcomes the pull rod spring and presses the push rod and the roller down. The specific pressing position is determined by the relative position of the roller and the centering valve striker. When the roller presses on the second height surface 1052 of the centering valve striker, the main valve is in position b. At this time, the second hydraulic chamber of the actuator hydraulic cylinder connected to the A port receives the pressure oil, and the first hydraulic chamber connected to the B port receives the return oil, and the rotary actuator moves from the positive direction to the zero direction. When the roller is pressed on the second height surface 1051 of the centering valve striker, the main valve is in position d, at which time the first hydraulic chamber connected to port B receives pressure oil, and the second hydraulic chamber of the actuator hydraulic cylinder connected to port A receives return oil, and the rotary actuator moves from the negative direction to the zero degree direction. When the roller stops at a certain point on the inclined surface 1053 of the centering valve striker, the main valve is in position c, and at this time, the rotary actuator is exactly 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 passes the pressure oil at the control oil port P1 of the emergency device to the hydraulic system circuit conversion control oil port P2, to ensure 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 passes the pressure oil at the system hydraulic source of the hydraulic system to the hydraulic system circuit conversion control oil port P2, to ensure 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 has a pump-controlled circuit; the valve-controlled circuit device has 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 The A01 and B01 ports are connected to the two hydraulic chambers of the actuator hydraulic cylinder), the third port K of the pump control driving source is connected to the hydraulic control reversing valve 609, and the hydraulic control reversing valve 609 is connected to the pump control main valve 608. In some embodiments, the pump control 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 the embodiment of the present application, the hydraulic system is controlled to switch between the pump-controlled circuit and the valve-controlled circuit through a pump-valve conversion valve. 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, so that the pump-controlled main valve 608 is switched from the working position to the bypass position, so that the first port A11 and the second port B11 of the pump-controlled driving source are bypassed;

[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 driving 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-controlled 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 K01 port is connected to the hydraulic system circuit conversion control oil port P2. The emergency hydraulic source is connected to the safety protection device. When the safety protection device is activated, the emergency hydraulic source is activated, and the emergency hydraulic source K01 port produces pressure oil. In some embodiments, the safety protection device is a device that cuts off the driving pressure oil of the pump control circuit and the valve control circuit of the actuator hydraulic cylinder in an emergency state to achieve safety protection of the actuator hydraulic cylinder. In some embodiments, the safety protection device is an emergency manual mechanism or an automatic trigger 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, and 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 hydraulic-controlled one-way valve 612 , and the pump-valve conversion valve 601 .

[0084] When the first solenoid reversing valve 605 is at the set potential, the first port P11 of the valve-controlled hydraulic source is connected with the hydraulically controlled one-way valve 612, the pump-valve conversion valve 601, and the hydraulic reversing valve 610 through the first solenoid 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, 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 in the off state, 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 the cut-off state, and the valve-controlled circuit is in the 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-driving 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. The pump-controlled main valve 608 has a connecting position and a shutoff position. The pump-controlled main valve 608 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, and 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, and reversing can be achieved.

[0088] The hydraulic reversing valve 610 is a two-position three-way hydraulic reversing valve. The hydraulic reversing valve 610 has a valve control position and an emergency position. The hydraulic reversing valve 610 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 electromagnetic reversing valve 605, and 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 also includes a second electromagnetic reversing valve 606 , which is connected to the servo valve conversion valve 607 , and 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 electromagnetic 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 conversion valve 607. In some embodiments, the servo valve conversion 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 conversion valve 607 is connected to the second electromagnetic 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 be used as the main servo valve, and the second servo valve 604 can be used 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, the first solenoid reversing valve 605 and the second solenoid reversing valve 606 are both 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, the control of the valve control circuit and the switching of the main and standby servo valves are realized by controlling the power on and off of the first solenoid reversing valve 605 and the second solenoid reversing valve 606 and the connection and cutoff of the servo valve switching valve 607 with the first servo valve 603 and the second servo valve 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 in the figure, Figure 4 Connected to port D).

[0096] The first valve-controlled 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 selection 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 up or the automatic trigger sensor mechanism of the hydraulic cylinder safety protection device is started, the pressure oil at port K01 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 only 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 protection scope 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 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 a rotary actuator. The stroke limiting and protection device includes: The limit position limiting device comprises a stroke limiting valve and a stop check valve, wherein the stroke limiting valve and the stop check valve are both provided with two stroke limiting valves, the two stroke limiting valves are respectively installed in the first hydraulic chamber and the second hydraulic chamber, and the two stop check valves are respectively installed between the first hydraulic chamber and the second hydraulic chamber, and the stroke limiting valve is used to open when the piston rod of the hydraulic cylinder reaches the limit position, so that the first hydraulic chamber and the second hydraulic chamber are connected; A speed limiting device, the speed limiting device comprising a proximity switch (15) 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 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 functional isolation valve (11), and a centering signal valve (12), the centering valve being connected to the centering signal valve, the centering signal valve being connected to the centering functional isolation valve, and the centering valve (10) being connected to the actuator hydraulic cylinder; the centering signal valve (12) being used to open according to a centering signal, so that pressure oil acts on the centering valve (10) through the centering functional isolation valve (11) and the centering signal valve (12), thereby placing the centering valve in a zero position; The centering valve comprises 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, and the collision surface 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 of the hydraulic system according to claim 2, characterized in that: The travel limiting valve is a two-position, two-way mechanical hydraulic reversing valve; The travel-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 reversing valve.

4. The stroke limiting and protecting device of the 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 protecting device also includes a fixed-center signaling valve (14), which is connected to the fixed-center signaling valve (12). The fixed-center signaling valve is a two-position three-way electromagnetic reversing valve. The fixed-center signaling valve (12) has a hydraulic control chamber, which is connected to the fixed-center signaling valve, and the fixed-center signaling valve is connected to the fixed-center 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 protecting device also includes a cut-off selector valve (13), The cut-off selection valve 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 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 actuator hydraulic cylinder.

8. A hydraulic system, characterized in that: The hydraulic system comprises the stroke limiting and protection device as claimed in 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 a rotary actuator. The electrical control box is connected to the centering signaling valve (14) and the stroke-limiting signaling valve; The electrical control box is used to receive the signal of the proximity switch and send a control signal to the limit-range signal-transmitting valve according to the signal; The electrical control box is used to send a centering signal to the 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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