Pilot-operated reversing valve

Abstract

The utility model relates to the technical field of hydraulic systems, in particular to a pilot-operated reversing valve. A pilot-operated type reversing valve comprises a main valve, a pilot-operated type reversing valve body and a pilot-operated type reversing valve body, the pilot valve is communicated with the two pilot cavities through two pilot oil ways respectively, and the pilot valve controls pilot oil to enter the pilot cavities; the two electromagnetic valves are located on the two pilot oil ways respectively, pilot oil is supplied to the pilot valves and the two electromagnetic valves at the same time, and under the control of the electromagnetic valves, the pilot oil flows through the pilot valves and the two electromagnetic valves. And one of the pilot oil reaching the electromagnetic valve through the pilot valve and the pilot oil directly reaching the same electromagnetic valve enters the corresponding pilot cavity. The technical problem that in the prior art, due to the fact that a pilot electromagnetic valve breaks down, a main valve cannot work is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic system technical field, especially a pilot type reversing valve. BACKGROUND

[0002] The reversing valve in prior art is mostly composed of a main valve and a pilot valve, the pilot valve controls the pilot oil entering the pilot chamber of the main valve, and further controls the reversing of the main valve. The file with the application number CN201811253043.5 discloses a position monitoring electro-hydraulic reversing valve, which is composed of a pilot electromagnetic valve, a main valve body, a main valve core, a spring, an end cover, a sealing ring, a position detection switch and a locking nut. The lower part of the main valve body is provided with a valve core hole, and the upper part of the main valve body is provided with two pilot oil channels. The main valve core is arranged in the valve core hole of the main valve body. The pilot electromagnetic valve is arranged on the upper surface of the main valve body, and the control oil port thereof is connected with the pilot control oil port of the main valve body. The end cover is arranged at both ends of the main valve body, and the two ends of the main valve core are arranged in the spring cavities of the end cover. The spring is arranged at the two ends of the main valve core and located in the spring cavities of the end cover. The end cover is provided with an end cover pilot oil channel, one end of which is connected with the pilot oil channel of the main valve body, and the other end thereof is communicated with the end cover spring cavity. The position detection switch is arranged in the position detection switch mounting hole arranged in the lower part of the end cover through screw thread. The locking nut is arranged on the position detection switch to lock the position detection switch. The position detection switch is provided with a sealing groove, and the sealing ring is arranged in the sealing groove to form a seal between the end cover.

[0003] The above structure controls the pilot oil by the pilot electromagnetic valve, and further controls the state of the main valve. However, once the electromagnet of the pilot electromagnetic valve fails or the PLC controlling the pilot valve fails, the main valve cannot work. UTILITY MODEL CONTENTS

[0004] In order to solve the technical problem that the main valve cannot work due to the failure of the pilot electromagnetic valve in the prior art, the utility model provides a pilot type reversing valve, which solves the above technical problem.

[0005] In order to solve the above technical problem, the utility model provides a pilot type reversing valve, which comprises:

[0006] A main valve, two pilot chambers are formed at the two ends of the main valve;

[0007] A pilot valve, the pilot valve is communicated with the two pilot chambers through two pilot oil paths respectively, and the pilot valve controls the pilot oil to enter the pilot chamber;

[0008] The electromagnetic valves are two, two electromagnetic valves are respectively located on two pilot oil paths, pilot oil is simultaneously supplied to the pilot valve and the two electromagnetic valves, and pilot oil reaching the electromagnetic valve through the pilot valve and pilot oil directly reaching the same electromagnetic valve are selectively entered into a corresponding pilot cavity under control of the electromagnetic valve.

[0009] According to an embodiment of the utility model, pilot oil is supplied to the pilot valve through a first oil supply path, and pilot oil is supplied to the electromagnetic valve through a second oil supply path, and the first oil supply path and the second oil supply path are communicated.

[0010] According to an embodiment of the utility model, the pilot oil is taken from a pilot oil port X and / or a pressure oil port P.

[0011] According to an embodiment of the utility model, the pilot oil is taken from a pilot oil port X and the pressure oil port P, and a first on-off structure is arranged on an oil path of the pressure oil port P for supplying oil to two oil supply paths.

[0012] According to an embodiment of the utility model, the electromagnetic valve is a two-position valve, when the electromagnetic valve is located at an initial position, a pilot oil path of the pilot valve to the pilot cavity is in a communication state, and the second oil supply path and the pilot cavity are in a disconnected state; when the electromagnetic valve is reversed after being powered, the pilot oil path of the pilot valve to the pilot cavity is in a disconnected state, and the second oil supply path and the pilot cavity are in a communication state.

[0013] According to an embodiment of the utility model, a, b and c oil ports are arranged on the electromagnetic valve, the a oil ports of the two electromagnetic valves are communicated with the second oil supply path, the b oil ports of the two electromagnetic valves are respectively communicated with two working oil ports d of the pilot valve, and the c oil ports of the two electromagnetic valves are respectively communicated with two pilot cavities, when the electromagnetic valve is located at the initial position, the b oil port is communicated with the c oil port; when the electromagnetic valve is reversed after being powered, the a oil port is communicated with the c oil port.

[0014] According to an embodiment of the utility model, a p oil port and a t oil port are further arranged on the pilot valve, the p oil port is communicated with the first oil supply path, and the t oil port is used for returning oil, when the pilot valve is located at a middle position, the two working oil ports d are both communicated with the t oil port, when the pilot valve is located at two working positions, one working oil port d is communicated with the p oil port, and the other working oil port d is communicated with the t oil port.

[0015] According to an embodiment of the utility model, the t oil port is communicated with a pilot return oil port Y and a main return oil port T, and a second on-off structure is arranged on an oil path of the t oil port to the main return oil port T.

[0016] According to one embodiment of the utility model, the end of the pilot valve is provided with an operating handle.

[0017] According to one embodiment of the utility model, the main valve and the pilot valve are assembled by stacking the transition valve block, and the two electromagnetic valves are inserted into the two ends of the transition valve block and located between the main valve and the pilot valve.

[0018] Based on the above technical solution, the utility model can realize the following technical effects:

[0019] The pilot type reversing valve of the utility model, by setting electromagnetic valve on two pilot oil circuit between main valve and pilot valve respectively, pilot oil is supplied to pilot valve and electromagnetic valve simultaneously, then pilot oil can enter pilot oil cavity through pilot valve and electromagnetic valve, also can directly enter pilot oil cavity through electromagnetic valve. When pilot valve works normally, pilot oil can enter and exit pilot cavity under the control of pilot valve to control the reversing of main valve; when pilot valve fails, pilot oil can enter pilot cavity through electromagnetic valve to realize the reversing of main valve. That is, when pilot valve fails, the reversing of main valve can also be controlled through two electromagnetic valves, which adds electric emergency function to pilot type reversing valve; further limit the pilot oil controlled by electromagnetic valve to reach electromagnetic valve through pilot valve and the pilot oil directly reaching the same electromagnetic valve to enter corresponding pilot cavity, then when pilot valve works normally, the pilot oil directly supplied to electromagnetic valve is cut off without affecting the normal work of pilot valve.

[0020] The pilot type reversing valve of the utility model, pilot oil can be taken from pilot oil port X and pressure oil port P, the first on-off structure is arranged on the oil circuit of the two oil supply oil circuits of pressure oil port P, then through the first on-off structure, the source of pilot oil can be controlled, when the first on-off structure plays a blocking role, pilot oil comes from pilot oil port X, realizing external supply of pilot oil; when the first on-off structure does not play a blocking role, pilot oil comes from pressure oil port P, realizing internal supply of pilot oil.

[0021] The pilot type reversing valve of the utility model, by setting the working state of electromagnetic valve at different stations, when pilot valve is in normal working state, electromagnetic valve does not need to be operated, electromagnetic valve is in initial position, then the oil circuit of pilot valve to pilot cavity is in communication state, at this time, pilot valve can control pilot oil to enter and exit pilot cavity, control the reversing of main valve; when pilot valve is in fault state, pilot valve is in middle position, then corresponding electromagnetic valve is operated, pilot oil can enter corresponding pilot cavity, and the pilot oil of another pilot cavity can return through another electromagnetic valve and pilot valve, still realizing the reversing of main valve.

[0022] The pilot type reversing valve of the utility model, set up the structure of pilot valve, make pilot valve be in the middle position, two working oil port d all communicate with the oil return oil circuit, then when pilot valve appears the fault and is in the middle position, can operate an electromagnetic valve and make a pilot chamber enter oil, the other pilot chamber can return oil through the other electromagnetic valve and pilot valve, further set up t oil port communication pilot return oil port Y and main return oil port T, t oil port set up second on-off structure on the oil return oil circuit to main return oil port T, then through second on-off structure, can control the discharge of pilot oil, when second on-off structure plays the role of blocking, then pilot oil can be discharged to pilot return oil port Y, realize the discharge of pilot oil, when second on-off structure does not play the role of blocking, then pilot oil can be discharged to main return oil port T, realize the discharge of pilot oil in the inside,

[0023] The pilot type reversing valve of the utility model, the end of pilot valve is provided with an operating handle, the reversing of main valve can be manually operated and controlled, and a manual emergency function is added to the pilot type reversing valve.

[0024] The pilot type reversing valve of the utility model, set up main valve and pilot valve through transition valve block stacking assembly, two electromagnetic valves are inserted on both sides of transition valve block and located between main valve and pilot valve, then the pilot oil circuit between main valve and pilot valve can be set in transition valve block, and the stacking assembly mode has high integration degree and small volume. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 It is the hydraulic principle view of the pilot type reversing valve of the utility model,

[0026] Fig. 2 It is the perspective view of the pilot type reversing valve,

[0027] Fig. 3 It is the front view of the pilot type reversing valve,

[0028] In the drawing: 1-main valve;2-pilot valve;21-handle;3-electromagnetic valve;4-pilot oil circuit;41-first pilot oil circuit section;42-second pilot oil circuit section;51-first oil supply oil circuit;52-second oil supply oil circuit;61-first on-off structure;62-second on-off structure;7-transition valve block. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is merely illustrative in nature and in no way should be construed as any limitation on the present application and its applications or uses. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of the present application.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0031] The relative arrangement of components and steps, numerical expressions, and numerical values set forth in the embodiments are not intended to limit the scope of the present application unless specifically stated otherwise. At the same time, it should be understood that the sizes of the various parts shown in the drawings are not drawn in proportion to the actual proportions. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary, and not as limiting. Therefore, other examples of the example embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, so further discussion of them is not necessary in subsequent drawings.

[0032] In the description of the present application, it should be understood that the orientation words such as "front, rear, upper, lower, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0033] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0034] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0035] like Figs. 1-3 As shown, this embodiment provides a pilot-operated directional valve, including a main valve 1, a pilot valve 2, and a solenoid valve 3. Pilot chambers are formed at both ends of the main valve 1. The pilot valve 2 is connected to the pilot chambers via a pilot oil passage 4. The solenoid valve 3 is located on the pilot oil passage 4. Pilot oil is supplied to both the pilot valve 2 and the solenoid valve 3 simultaneously. When the pilot valve 2 is working normally, pilot oil flows in and out of the pilot chambers under the control of the pilot valve 2, controlling the main valve 1 to switch. When the pilot valve 2 malfunctions, pilot oil directly enters the pilot chambers via the solenoid valve 3, controlling the main valve 1 to switch. The solenoid valve 3 provides an electric emergency function for the pilot-operated directional valve.

[0036] Main valve 1 is a directional control valve, with oil ports connected to pressure oil port P and main return oil port T respectively. Main valve 1 controls the flow of hydraulic fluid into and out of the actuator to drive the actuator. Main valve 1 achieves directional control under the action of pilot oil.

[0037] Pilot valve 2 is used to control the entry and exit of pilot oil into the pilot chamber of main valve 1. Pilot valve 2 is connected to the two pilot chambers of main valve 1 through two pilot oil passages 4 respectively.

[0038] Specifically, the pilot valve 2 is a three-position four-way valve, and the pilot valve 2 is provided with a p oil port, a t oil port and two working oil ports d. The pilot oil is supplied to the pilot valve 2 through a first oil supply oil way 51, the p oil port is communicated with the first oil supply oil way 51, the t oil port is used for returning the pilot oil, and the two working oil ports d are respectively communicated with two pilot oil ways 4. When the pilot valve 2 is in the middle position, the two working oil ports d are both communicated with the t oil port; when the pilot valve 2 is in the two working positions, one working oil port d is communicated with the p oil port, and the other working oil port d is communicated with the t oil port.

[0039] As a preferred technical solution of the embodiment, the pilot valve 2 can be an electromagnetic proportional reversing valve, and electromagnets are arranged on both sides of the pilot valve 2. Specifically, the left electromagnet is powered to move the pilot valve spool to the right, the right electromagnet is powered to move the pilot valve spool to the left, and the displacement of the spool is proportional to the electrical signal.

[0040] As a preferred technical solution of the embodiment, the pilot valve 2 is further provided with a handle 21. When the pilot valve 2 fails, the handle 21 can be operated to reverse the pilot valve 2, and the pilot valve 2 is manually driven to reverse.

[0041] The electromagnetic valves 3 are two, and the two electromagnetic valves 3 are respectively arranged on the two pilot oil ways 4. The two electromagnetic valves 3 can control the opening and closing of the pilot oil way 4 where the electromagnetic valve 3 is located. The pilot oil is simultaneously supplied to the pilot valve 2 and the two electromagnetic valves 3, and the electromagnetic valve 3 can control the pilot oil reaching the electromagnetic valve 3 through the pilot valve 2 and the pilot oil directly reaching the same electromagnetic valve 3 to enter the corresponding pilot cavity.

[0042] Specifically, the electromagnetic valve 3 can be a two-position valve. When the electromagnetic valve 3 is in the initial position, the pilot oil way 4 remains in the connected state, and the pilot oil can enter and exit the pilot cavity under the control of the pilot valve 2 to control the reversing of the main valve 1; when the electromagnetic valve 3 is powered to reverse, the pilot oil way 4 is in the disconnected state, the pilot valve 2 is disconnected from the pilot cavity, and the pilot oil directly supplied to the electromagnetic valve 3 can enter the corresponding pilot cavity.

[0043] As a preferred technical solution of the embodiment, the electromagnetic valve 3 is arranged on the pilot oil way 4 to separate the pilot oil way 4 into a first pilot oil way section 41 and a second pilot oil way section 42. The electromagnetic valve 3 is communicated with the corresponding pilot cavity through the first pilot oil way section 41, and the electromagnetic valve 3 is communicated with the working oil port d of the pilot valve 2 through the second pilot oil way section 42. The pilot oil is supplied to the electromagnetic valve 3 through a second oil supply oil way 52, and the electromagnetic valve 3 switches to control the communication between the first pilot oil way section 41 and the second pilot oil way section 42 or the communication between the first pilot oil way section 41 and the second oil supply oil way 52. In the initial state, the first pilot oil way section 41 is communicated with the second pilot oil way section 42 through the electromagnetic valve 3; after being powered to reverse, the first pilot oil way section 41 is communicated with the second oil supply oil way 52 through the electromagnetic valve 3.

[0044] As a preferred technical solution of the embodiment, the electromagnetic valve 3 can be a two-position three-way valve, and the electromagnetic valve 3 is provided with an a oil port, a b oil port and a c oil port. The a oil ports of the two electromagnetic valves 3 are communicated with the second oil supply oil path 52, the b oil ports of the two electromagnetic valves 3 are respectively communicated with the two working oil ports d of the pilot valve 2, and the c oil ports of the two electromagnetic valves 3 are respectively communicated with the two pilot cavities of the main valve 1. When the electromagnetic valve 3 is in the initial position, the b oil port is communicated with the c oil port. When the electromagnetic valve 3 is reversed after being electrified, the a oil port is communicated with the c oil port.

[0045] As a preferred technical solution of the embodiment, the electromagnetic valve 3 can be an electromagnetic ball valve.

[0046] The pilot oil is supplied to the pilot valve 2 through the first oil supply oil path 51 and is supplied to the two electromagnetic valves 3 through the second oil supply oil path 52. The first oil supply oil path 51 and the second oil supply oil path 52 are communicated, and the pilot valve 2 and the electromagnetic valve 3 introduce the pilot oil of the same oil pressure.

[0047] As a preferred technical solution of the embodiment, the pilot oil can be taken from the pilot oil port X and / or the pressure oil port P.

[0048] As a preferred technical solution of the embodiment, the pilot oil can be taken from the pilot oil port X and the pressure oil port P. The pressure oil port P is provided with a first on-off structure 61 on the oil path for supplying oil to the first oil supply oil path 51 and the second oil supply oil path 52. When the first on-off structure 61 plays a blocking role, the pilot oil comes from the pilot oil port X, realizing external supply of the pilot oil. When the first on-off structure 61 does not play a blocking role, the pilot oil comes from the pressure oil port P, realizing internal supply of the pilot oil. The first on-off structure 61 can be a plug, and the blocking role is realized by installing the plug, and the blocking role is removed by removing the plug.

[0049] The t oil port of the pilot valve 2 can be communicated with the pilot return oil port Y and the main return oil port T to perform oil return. The oil path from the t oil port to the main return oil port T is provided with a second on-off structure 62. Through the second on-off structure 62, the discharge of the pilot oil can be controlled. When the second on-off structure 62 plays a blocking role, the pilot oil can be discharged to the pilot return oil port Y, realizing external discharge of the pilot oil. When the second on-off structure 62 does not play a blocking role, the pilot oil can be discharged to the main return oil port T, realizing internal discharge of the pilot oil. The second on-off structure 62 can be a plug, and the blocking role is realized by installing the plug, and the blocking role is removed by removing the plug.

[0050] As a preferred technical solution of the embodiment, the functions of the first on-off structure 61 and the second on-off structure 62 are to adjust the control mode of the valve. When the first on-off structure 61 and the second on-off structure 62 are both installed, the pilot oil is supplied from the outside, and the pilot oil is discharged to the outside. When the first on-off structure 61 is installed and the second on-off structure 62 is removed, the pilot oil is supplied from the outside, and the pilot oil is discharged internally. When the first on-off structure 61 is removed and the second on-off structure 62 is installed, the pilot oil is supplied internally, and the pilot oil is discharged to the outside. When the first on-off structure 61 and the second on-off structure 62 are both removed, the pilot oil is supplied internally, and the pilot oil is discharged internally. Fig. 1As shown, the control mode is external supply and external discharge; when only the first on-off structure 61 is cancelled, the pressure oil port P and the pilot oil port X are communicated, the control mode is internal supply and external discharge; when only the second on-off structure 62 is cancelled, the pilot return oil port Y and the main return oil port T are communicated, the control mode is external supply and internal discharge; when the first on-off structure 61 and the second on-off structure 62 are both cancelled, the pressure oil port P and the pilot oil port X are communicated, the pilot return oil port Y and the main return oil port T are communicated, and the control mode is internal supply and internal discharge.

[0051] As shown in the figure, in the specific structure assembly, the main valve 1 and the pilot valve 2 are assembled together through the transition valve block 7, the main valve 1 and the pilot valve 2 are stacked and assembled on both sides of the transition valve block 7, the pilot oil way 4 can be arranged in the transition valve block 7, and the two electromagnetic valves 3 are assembled on the transition valve block 7. Figs. 2-3 As shown in the figure, in the specific structure assembly, the main valve 1 and the pilot valve 2 are assembled together through the transition valve block 7, the main valve 1 and the pilot valve 2 are stacked and assembled on both sides of the transition valve block 7, the pilot oil way 4 can be arranged in the transition valve block 7, and the two electromagnetic valves 3 are assembled on the transition valve block 7.

[0052] As a preferred technical solution of the embodiment, the two electromagnetic valves 3 are inserted and assembled at both ends of the transition valve block 7, and the two electromagnetic valves 3 are located between the main valve 1 and the pilot valve 2.

[0053] Based on the above technical solution, the working principle of the pilot type reversing valve of the embodiment is as follows:

[0054] Normal working condition:

[0055] The two electromagnetic valves 3 are in the initial position, the displacement of the pilot valve spool is proportional to the electrical signal by controlling the energization of the end electromagnet of the pilot valve 2 to control the displacement of the pilot valve spool, the pilot valve 2 controls the oil inlet of one pilot chamber and the oil return of the other pilot chamber.

[0056] Electric emergency working condition:

[0057] In the case that the pilot valve 2 fails due to proportional electromagnet failure or PLC failure, the pilot valve 2 is in the middle position and cannot work, and the two electromagnetic valves 3 can be used to control the reversing of the main valve 1.

[0058] The reversing can be realized by controlling the energization of one electromagnetic valve 3, the pilot oil enters one pilot chamber through the electromagnetic valve 3, and the other electromagnetic valve 3 is still in the initial position, and the other pilot chamber can return oil through the other electromagnetic valve 3 and the pilot valve 2, so that the reversing of the main valve 1 can be realized.

[0059] Manual emergency working condition:

[0060] In the case of power failure, the handle 21 on the pilot valve 2 can also be used to control the reversing of the pilot valve 2 and indirectly control the reversing of the main valve 1.

[0061] Push the handle 21, and the pilot valve spool can be moved to the first working position; pull the handle 21, and the pilot valve spool can be moved to the second working position, and the displacement of the valve spool is proportional to the displacement of the handle 21.

[0062] Therefore, the pilot type reversing valve can realize the control of the reversing of the main valve 1, even if the pilot valve 2 fails, the electric emergency mode or the manual emergency mode can be used to ensure the normal work of the main valve 1.

[0063] In addition, for the pilot oil port X and the pilot return oil port Y, when the load pressure changes little and the back pressure of the main return oil port T is stable, the internal supply and internal discharge form can be used, and the pilot oil port X, the pilot return oil port Y and the corresponding oil channel do not need to be additionally designed; when the load pressure fluctuates greatly or the load pressure is low, the internal supply form is not suitable any more, because the action of the main valve 1 controlled by the pilot valve 2 needs a certain pressure, and at this time, the selection of the internal supply form may cause the main valve 1 to be unable to reverse, therefore, the external supply form is more suitable, and the separate pressure oil is provided for the pilot oil port X to control the main valve 1.

[0064] When the system return oil pressure fluctuates little, the external discharge form can be selected, but when multiple actuators act at the same time, the return oil back pressure fluctuates greatly, at this time, the control precision of the pilot valve 2 to the main valve 1 is influenced, and the external discharge form needs to be used to provide the control system with precision.

[0065] The embodiments of the utility model are described in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range possessed by those skilled in the art without departing from the purpose of the utility model.

Claims

1. A pilot-operated directional valve, characterized in that, include: The main valve (1) has pilot chambers formed at both ends; Pilot valve (2), the pilot valve (2) is connected to two pilot chambers respectively through two pilot oil passages (4), the pilot valve (2) controls the pilot oil to enter the pilot chamber; There are two solenoid valves (3), which are located on the two pilot oil circuits (4) respectively. Pilot oil is supplied to the pilot valve (2) and the two solenoid valves (3) at the same time. Under the control of the solenoid valve (3), the pilot oil that reaches the solenoid valve (3) through the pilot valve (2) and the pilot oil that directly reaches the same solenoid valve (3) can be selected to enter the corresponding pilot chamber.

2. The pilot-operated directional valve according to claim 1, characterized in that, Pilot oil is supplied to the pilot valve (2) via the first oil supply line (51), and pilot oil is supplied to the solenoid valve (3) via the second oil supply line (52). The first oil supply line (51) and the second oil supply line (52) are connected.

3. A pilot-operated directional valve according to any one of claims 1-2, characterized in that, The pilot oil is taken from pilot oil port X and / or pressure oil port P.

4. A pilot-operated directional valve according to any one of claims 1-2, characterized in that, The pilot oil is taken from the pilot oil port X and the pressure oil port P. The pressure oil port P is provided with a first on / off structure (61) on the oil supply line to the two oil supply lines.

5. A pilot-operated directional valve according to claim 2, characterized in that, The solenoid valve (3) is a two-position valve. When the solenoid valve (3) is in the initial position, the pilot oil passage (4) from the pilot valve (2) to the pilot chamber is in a connected state, and the second oil supply passage (52) is in a disconnected state from the pilot chamber. When the solenoid valve (3) is energized and reversed, the pilot oil passage (4) from the pilot valve (2) to the pilot chamber is in a disconnected state, and the second oil supply passage (52) is in a connected state from the pilot chamber.

6. A pilot-operated directional valve according to claim 5, characterized in that, The solenoid valve (3) is provided with an a port, a b port and a c port. The a ports of the two solenoid valves (3) are connected to the second oil supply circuit (52). The b ports of the two solenoid valves (3) are respectively connected to the two working ports of the pilot valve (2). The c ports of the two solenoid valves (3) are respectively connected to the two pilot chambers. When the solenoid valve (3) is in the initial position, the b port is connected to the c port. When the solenoid valve (3) is energized and reversed, the a port is connected to the c port.

7. A pilot-operated directional valve according to claim 6, characterized in that, The pilot valve (2) is provided with a p port and a t port. The p port is connected to the first oil supply circuit (51), and the t port is used for oil return. When the pilot valve (2) is in the neutral position, both working ports d are connected to the t port. When the pilot valve (2) is in two working positions, one working port d is connected to the p port, and the other working port d is connected to the t port.

8. A pilot-operated directional valve according to claim 7, characterized in that, The t-port connects the pilot return oil port Y and the main return oil port T, and a second on / off structure (62) is provided on the oil path from the t-port to the main return oil port T.

9. A pilot-operated directional valve according to claim 1, characterized in that, The pilot valve (2) is provided with an operating handle (21) at its end.

10. A pilot-operated directional valve according to claim 1, characterized in that, The main valve (1) and the pilot valve (2) are stacked and assembled through a transition valve block (7). Two solenoid valves (3) are inserted at both ends of the transition valve block (7) and located between the main valve (1) and the pilot valve (2).

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