CN115978039A - Hydraulic control system and aerial work machine - Google Patents

Abstract

The invention relates to engineering machinery hydraulic equipment, and provides a hydraulic control system which comprises an oil inlet oil way, an oil return way, an oil discharge way, an oil inlet linkage and a plurality of working linkages, wherein a main valve core of each working linkage comprises an oil inlet, an oil return port and two working oil ports which are respectively connected with an actuator, when the oil supply pressure of the actuator is lower than a set value, the actuator does not act, part or all of the working linkages are provided with control valves, the control valves are respectively connected with the main valve core of the working linkage and the oil discharge way, when the main valve core of the working linkage moves to enable one working oil port of the main valve core to be connected with the oil inlet, the control valves can be connected with the oil inlet, and under the condition that the main valve core of the working linkage receives a middle control instruction, the control valves can control the main valve core to be communicated with the oil discharge way. When the valve core is blocked and not in the middle position, the hydraulic control system avoids the blocked valve core from conveying hydraulic oil to the actuator, prevents the actuator from generating uncontrollable action, and improves the safety of the hydraulic system. The invention also provides an aerial work machine.

Description

Hydraulic control system and aerial work machine

Technical Field

The invention relates to engineering machinery hydraulic equipment, in particular to a hydraulic control system. In addition, the invention also relates to an aerial working machine.

Background

Generally, the high-altitude operation machine needs to lift people and objects to a certain height, and perform tasks such as maintenance and equipment installation.

The existing high-altitude operation machinery controls various actions of an arm support through a hydraulic system, and generally comprises a tower arm support, a main arm telescopic arm support, a fly arm support, leveling and the like. The hydraulic main valve connects the action valve cores of the tower arm, the main arm expansion, the fly arm, the leveling and the like in parallel so as to convey hydraulic oil to different action valve cores and control the action of the actuator, but because a hydraulic system is influenced by cleanliness, valve clamping phenomena frequently occur, such as the reversing of the valve core of the tower arm and the action of the arm support of the tower arm, the valve core of the main arm is clamped, the valve core of the main arm is not in a middle position, the hydraulic oil simultaneously flows to the valve core of the tower arm and the valve core of the main arm, and the arm support of the tower arm and the arm support of the main arm simultaneously act, so that life danger can be caused to people on the high-altitude operation machinery.

Therefore, how to avoid the occurrence of safety accidents under the condition of the valve core jamming is a problem to be urgently needed to be solved by the technical personnel in the field.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a hydraulic control system, which can prevent a stuck valve core from conveying hydraulic oil to an actuator under the condition that the valve core is not stuck in a middle position, prevent the actuator from generating uncontrollable action and improve the safety of the hydraulic system.

The invention also provides an aerial work machine, which can ensure the safety of aerial work without uncontrollable action of each actuator under the condition that the valve core is stuck and not in the middle position.

In order to solve the technical problem, the invention provides a hydraulic control system, which comprises an oil inlet channel, an oil return channel, an oil discharge channel, an oil inlet pair and a plurality of working pairs, wherein the oil inlet channel is connected with the oil inlet pair and each working pair so as to supply oil, the oil return channel is connected with the oil inlet pair and each working pair so as to return oil, a main valve core of each working pair comprises an oil inlet connected with the oil inlet channel, an oil return port connected with the oil return channel and two working ports respectively connected with an actuator, and when the oil supply pressure of the actuator is lower than a set value, the actuator does not act, wherein part or all of the working pairs are provided with control valves respectively connected with the main valve cores of the working pairs and the oil discharge channel, when the main valve cores of the working pairs move so that one working port of the main valve cores of the working pairs is connected with the oil inlet, the main valve can be connected with the oil inlet, and when the main valve cores of the working pairs receive a neutral control instruction, the control valves can control the main valve can control the oil discharge channel to be communicated with the oil discharge channel.

Specifically, each working link comprises a telescopic link, a main arm link and a tower arm link, and the control valve is arranged on each telescopic link, each main arm link and each tower arm link.

The main arm main valve core comprises a main arm oil inlet, a main arm oil return port, a main arm first working oil port and a main arm second working oil port, the main arm main valve core at least comprises a first working position, a second working position and a middle position, the main arm oil inlet is communicated with the main arm first working oil port, and the main arm oil return port is communicated with the main arm second working oil port when the main arm main valve core is in the first working position state; when the main arm main valve core is in a second working position state, the main arm oil inlet is communicated with the second working oil port of the main arm, and the main arm oil return port is communicated with the first working oil port of the main arm; the main valve core of the main arm has a Y-shaped middle position function; when the main arm main valve element is in a first working position or a second working position, the main arm control valve is connected with the main arm oil inlet, and when the main arm main valve element receives a middle position instruction, the main arm control valve can control the main arm main valve element to be communicated with the oil unloading oil way.

Preferably, the main arm is provided with a main arm pressure compensation valve, the oil inlet oil path is connected to the oil inlet of the main arm through the main arm pressure compensation valve, the main arm main valve core includes a main arm second oil port, a main arm third oil port, a main arm fifth oil port and a main arm sixth oil port, the main arm fifth oil port is connected to the main arm second working oil port, the main arm sixth oil port is connected to the main arm first working oil port, the main arm second oil port and the main arm third oil port are connected to the control end of the main arm pressure compensation valve through the main arm first oil path, the main arm sixth oil port is communicated with the main arm third oil port when the main arm main valve core is at the first working position, and the main arm fifth oil port is communicated with the main arm second oil port when the main arm main valve core is at the second working position.

Preferably, the hydraulic control system comprises load feedback oil paths, the output pressure of the main valve core of each working connection can be led into the load feedback oil paths, the oil inlet connection is provided with a constant-differential pressure reducing valve, and the constant-differential pressure reducing valve can control the oil flow of the oil inlet oil paths according to the oil pressure in the load feedback oil paths.

Specifically, the telescopic link comprises a telescopic main valve core and a first shuttle valve, the main arm link comprises a second shuttle valve, the tower arm link comprises a tower arm main valve core and a third shuttle valve, a comparison oil port of the third shuttle valve is connected with an output oil port of the tower arm main valve core, two comparison oil ports of the second shuttle valve are respectively connected with the first oil path of the main arm and the output oil port of the third shuttle valve, two comparison oil ports of the first shuttle valve are respectively connected with the output oil port of the second shuttle valve and the output oil port of the telescopic main valve core, and the output oil port of the first shuttle valve is connected with the load feedback oil path.

The main arm control valve comprises a main arm first control valve and a main arm second control valve, the main arm main valve core comprises a main arm first oil port, a main arm fourth oil port, a main arm seventh oil port, a main arm first control oil port and a main arm second control oil port, the main arm first oil port and the main arm fourth oil port are both connected with the main arm first oil way, the main arm first control oil port is connected with the oil unloading oil way through a main arm second oil way, the main arm second control oil port is connected with the oil unloading oil way through a main arm third oil way, the main arm first control valve is arranged on the main arm second oil way, the main arm second control valve is arranged on the main arm third oil way, the main arm first control oil port is communicated with the main arm fourth oil port when the main arm main valve core is at a first working position, and the main arm second control oil port is communicated with the main arm first oil port when the main arm oil port is at a second working position, and the seventh oil port connected with the main arm first oil unloading oil port is communicated with the main arm first control valve when the main arm oil port is at a second working position.

Preferably, the main arm linkage is provided with a main arm first overflow valve and a main arm second overflow valve, the main arm first overflow valve and the main arm first control valve are connected in parallel on the main arm second oil path, and the main arm second overflow valve and the main arm second control valve are connected in parallel on the main arm third oil path.

Preferably, part or all of the working units are provided with bidirectional balance valves, two working oil ports of the working units are respectively connected with two oil inlets of the bidirectional balance valves in a one-to-one correspondence manner, and two oil outlets of the bidirectional balance valves are respectively connected with the actuator.

Furthermore, the invention also provides an aerial work machine which comprises the hydraulic control system in any one of the technical schemes.

Through the scheme, the invention has the following beneficial effects:

the hydraulic control system of the invention connects the main valve core of the working union with the oil discharge path through the control valve, when the main valve core of the working union moves, and one working oil port of the main valve core is connected with the oil inlet, the control valve can be connected with the oil inlet, so that the oil inlet of the main valve core is connected with the oil discharge path through the control valve, and the control valve can be opened only under the condition that the main valve core of the working union receives a middle control instruction, therefore, even if the main valve core is blocked and does not move to the middle position, the hydraulic oil conveyed to the main valve core from the oil inlet path can directly flow to the oil discharge path through the control valve for pressure relief, so that the hydraulic oil can not build enough pressure and is conveyed to an actuator from the working oil port, and the actuator of the working union can not generate uncontrollable action. When the working link needs to control the actuator to act, the main valve core is located at a working position, the control valve is closed at the moment, the oil inlet is blocked from the oil unloading oil path, and therefore hydraulic oil conveyed to the actuator from the working oil port by the main valve core has enough pressure, the actuator can enter and exit oil, and the actuator can finish the action.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a hydraulic schematic of an exemplary embodiment of a hydraulic control system according to the present invention;

fig. 2 is an enlarged view at H in fig. 1.

Description of the reference numerals

1 oil inlet joint 11 main oil way

12 three-way pressure reducing valve 13 constant-difference pressure reducing valve

14 load feedback unloading valve 15 main overflow valve

2 telescopic joint 21 telescopic main valve core

22 first shuttle valve

3 main arm main valve core of main arm coupling 31

311 main arm first electromagnet 312 main arm second electromagnet

32 main arm control valve 321 main arm first control valve

322 main arm second control valve 33 main arm pressure compensation valve

34 main arm first oil path 35 second shuttle valve

36 main arm second oil path 37 main arm third oil path

38 main arm first overflow valve 39 main arm second overflow valve

4 tower arm is connected 41 tower arms main valve core

42 third shuttle valve

5 oil supply unit

100 oil inlet oil way and 200 oil return oil way

300 pilot oil circuit 400 load feedback oil circuit

500 oil discharge way

Oil return port of p main arm oil inlet t main arm

a main arm first working oil port b main arm second working oil port

c main arm first oil port d main arm first control oil port

e second oil port of main arm f third oil port of main arm

g main arm second control oil port h main arm fourth oil port

i the fifth oil port of the main arm j the sixth oil port of the main arm

The seventh oil port of the k main arm

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, and it is to be understood that the detailed description is provided only for the purpose of illustrating and explaining the present invention, and the scope of the present invention is not limited to the following detailed description.

In the description of the present invention, it should be noted that, unless otherwise explicitly stated or limited, the terms "formed," "provided," "disposed," "connected," and the like are to be construed broadly, and for example, the connection may be a direct connection, an indirect connection via an intermediate medium, a fixed connection, a detachable connection, or an integral connection; either directly or indirectly through intervening connectors, either internally or in cooperative relationship to each other. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

In the present invention, unless otherwise specified, the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are used merely for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention; the directional terminology of the present invention should be understood in conjunction with the actual installation state.

The invention provides a hydraulic control system, referring to fig. 1, as a specific embodiment of the hydraulic control system of the invention, comprising an oil inlet passage 100, an oil return passage 200, an oil discharge passage 500, an oil inlet unit 1 and a plurality of working units, wherein the oil inlet passage 100 connects the oil inlet unit 1 with each working unit to supply oil, the oil return passage 200 connects the oil inlet unit 1 with each working unit to return oil, a main valve core of the working unit comprises an oil inlet connected with the oil inlet passage 100, an oil return port connected with the oil return passage 200 and two working oil ports respectively connected with an actuator, the main valve core can supply oil and return oil to the actuator through the two working oil ports, when the oil supply pressure of the actuator is lower than a set value, the actuator does not act, wherein, part or all of the working couplings are provided with control valves which are respectively connected with the main valve cores of the working couplings and the oil discharge oil circuit 500, when the main valve core of the working connection moves to enable one working oil port of the main valve core of the working connection to be connected with the oil inlet, the control valve can be connected with the oil inlet, so that the oil inlet of the main valve element is connected with the oil discharge path 500 through the control valve, and under the condition that the main valve element of the working joint receives a middle control instruction, the control valve can be opened to control the main spool to communicate with the oil discharge passage 500, and therefore, even if the main valve core is not blocked and moves to the middle position, and other working links are running, the hydraulic oil which is conveyed from the oil inlet of the oil inlet oil path 100 to the blocked main valve core can directly flow to the oil discharge oil path 500 through the control valve for pressure relief, the hydraulic oil can not build enough pressure (the oil pressure is less than a set value) and is conveyed to the actuator, and the actuator of the working link is prevented from generating uncontrollable action, so that the stable operation of the hydraulic control system is ensured, and the safety of the hydraulic system is improved. In addition, when the main valve core of the working union is in the working position, the control valve is closed at the moment, so that the oil inlet is blocked from the oil discharge path 500, the hydraulic oil conveyed from the working oil port to the actuator by the main valve core has enough pressure (the oil pressure is greater than a set value), the actuator can supply oil and return oil, and the actuator can complete the action.

It should be noted that, in order to realize that the actuator does not act when the oil supply pressure is lower than the set value, under the preferable condition, part or all of the working units are provided with the bidirectional balance valve, two working oil ports of the working units are respectively connected with two oil inlets of the bidirectional balance valve in a one-to-one correspondence manner, and two oil outlets of the bidirectional balance valve are respectively connected with the actuator. The two-way balance valve comprises two same parts, and each part consists of a one-way valve and a pressure valve controlled by a reverse pipeline pilot, wherein the one-way valve allows oil to flow into an actuator with low pressure loss and keeps closed reversely. When oil flows through a first working oil path of the working unit and the pressure of the first working oil path reaches a set value, a pressure valve of a corresponding second working oil path is opened under the pilot control of the oil of the first working oil path, so that the actuator can return oil through the pressure valve of the second working oil path, and meanwhile, the first working oil path supplies oil to the actuator through a one-way valve, so that the actuator acts; therefore, the set value is the oil pressure of the pilot control of the pressure valve in the two-way balance valve, and when the oil pressure of the first working oil path is smaller than the set value, the pressure valve of the second working oil path cannot be opened, the one-way valve of the second working oil path is kept closed, and the load of the corresponding actuator is kept and no action is carried out when the main valve core of the working connection is in a neutral state. When the main valve core of the working union is blocked, the control valve corresponding to the working union is opened due to the fact that a middle control instruction is received, so that hydraulic oil flowing to the oil inlet of the main valve core of the working union through the oil inlet oil path 100 can directly flow to the control valve, the hydraulic oil can also be directly unloaded through the unloading valve, sufficient oil pressure cannot be built, an actuator cannot generate uncontrollable action under the action of the bidirectional balance valve, and safe operation of a hydraulic system is guaranteed.

Taking the aerial work platform as an example, referring to fig. 1, each work link comprises a telescopic link 2, a main arm link 3 and a tower arm link 4, and the telescopic link 2, the main arm link 3 and the tower arm link 4 are all provided with control valves, so that under the condition that a main valve core of the work link is blocked and cannot return to a middle position, uncontrollable actions of corresponding actuators can be avoided, collision of an arm support and other objects is prevented, and the life safety of personnel working aloft is ensured.

Specifically, referring to fig. 1 and 2, the main arm linkage 3 includes a main arm main valve core 31 and a main arm control valve 32, the main arm control valve 32 is respectively connected to the main arm main valve core 31 and an oil discharge path 500, the main arm main valve core 31 includes a main arm oil inlet p, a main arm oil return port t, a main arm first working oil port a and a main arm second working oil port b, the main arm first working oil port a is connected to a rodless cavity of a main arm oil cylinder (an actuator of the main arm linkage 3), the main arm second working oil port b is connected to a rod cavity of the main arm oil cylinder, the main arm main valve core 31 at least includes a first working position, a second working position and a middle position, when the main arm main valve core 31 is in the first working position (lower position in fig. 1), the main arm oil inlet p is communicated with the first working oil port a, and the main arm oil return port t is communicated with the second working oil port b, so as to enable the main arm oil cylinder to perform an extending action; when the main arm main valve core 31 is in the second working position state, the main arm oil inlet p is communicated with the main arm second working oil port b, and the main arm oil return port t is communicated with the main arm first working oil port a, so that the main arm oil cylinder can perform retraction action. When the main arm main valve core 31 is in the first working position or the second working position, the main arm control valve 32 is connected to the main arm oil inlet p, and when the main arm main valve core receives a first working position or a second working position instruction, the main arm control valve 32 is in a closed state, the main arm oil inlet p is blocked from the oil unloading oil path 500, the hydraulic oil fed from the main arm oil inlet p to the main arm main valve core 31 by the oil feeding oil path 100 can reach a set value, so that the bidirectional balance valve can be opened by the hydraulic oil flowing to the actuator from the main arm first working oil port a or the main arm second working oil port b, and the main arm oil cylinder can perform extending action or retracting action; under the condition that the main arm main valve core 31 receives a middle position instruction, the main arm control valve 32 is opened, so that the main arm main valve core 31 can be controlled to be communicated with the oil unloading oil way 500, even if the main arm main valve core 31 is blocked and does not return to the middle position, the main arm oil inlet p can be communicated with the oil unloading oil way 500 through the main arm control valve 32, when the oil inlet oil way 100 conveys hydraulic oil to the main arm oil inlet p, the main arm oil inlet p can directly flow to the oil unloading oil way 500 for unloading, so that the oil pressures in the working oil ways of the main arm first working oil port a and the main arm second working oil port b, which are connected with the actuator, cannot be accumulated to exceed a set value, the main arm oil cylinder cannot return oil through the bidirectional balance valve, uncontrollable action cannot be generated, and the safety of high-altitude operation is ensured. In addition, the main arm main valve core 31 has a Y-shaped middle position function, that is, when the main arm main valve core 31 is in a middle position state, the main arm first working oil port a and the main arm second working oil port b are both communicated with the main arm oil return port t, so that oil in a working oil path connecting the main arm first working oil port a and the main arm second working oil port b with the main arm oil cylinder is unloaded, and the load holding of the main arm oil cylinder is realized by matching with a bidirectional balance valve.

As a preferred embodiment of the hydraulic control system of the present invention, the main arm linkage 3 is provided with a main arm pressure compensation valve 33, the oil inlet path 100 is connected to the main arm oil inlet p through the main arm pressure compensation valve 33 to perform pressure difference compensation on the hydraulic oil output from the main arm main valve core 31, wherein the main arm main valve core 31 includes a main arm second oil port e, a main arm third oil port f, a main arm fifth oil port i, and a main arm sixth oil port j, the main arm fifth oil port i is connected to the main arm second working oil port b, the main arm sixth oil port j is connected to the main arm first working oil port a, the main arm second oil port e and the main arm third oil port f are commonly connected to the control end of the main arm pressure compensation valve 33 through the main arm first oil path 34, the main arm sixth oil port j and the main arm third oil port f are communicated when the main arm main valve core 31 is at the first working position, the main arm fifth oil port i and the main arm second oil port e are communicated when the main arm main valve core 31 is at the second working position, so that the output oil pressure of the main arm pressure compensation valve 33 is applied to the control end of the main arm pressure compensation valve 33 to make the main arm pressure compensation valve core 31 perform pressure compensation for constant pressure compensation and thereby making the pressure compensation for the main arm pressure compensation. Preferably, the primary arm first oil passage 34 is provided with an orifice to smooth out fluctuations in oil pressure in the passage.

Referring to fig. 1, the hydraulic control system of the present invention includes a pilot oil path 300, where the pilot oil path 300 is connected to the control end of the main spool of each working pair to control the main spool of each working pair to move to different positions, so as to control the corresponding actuator to operate, in order to supply oil, an oil inlet pair 1 is connected to an oil supply unit 5 through a main oil path 11, the oil supply unit 5 delivers hydraulic oil into the main oil path 11, an oil inlet path 100 is connected to the main oil path 11 to supply oil to the main spools of each working pair, the pilot oil path 300 is connected to the main oil path 11 through a three-way pressure reducing valve 12 to reduce the oil pressure of the main oil path 11 to a required pilot oil pressure, and the three-way pressure reducing valve 12 is also connected to an oil return path 200, so that overflow can be performed when the pressure reducing capability is insufficient, thereby avoiding potential safety hazards caused by excessive pilot oil pressure. Under the preferred circumstances, the oil supply unit 5 comprises gear pump and check valve, and the gear pump inhales oil from the hydraulic oil tank, and hydraulic oil gets into the main oil circuit 11 in the oil feed allies oneself with 1 through the check valve.

It should be noted that the hydraulic control system of the present invention further includes a load feedback oil path 400, the output pressure of the main valve core of each working connection can be led into the load feedback oil path 400, the oil inlet connection 1 is provided with a constant-differential pressure reducing valve 13, and the constant-differential pressure reducing valve 13 can control the oil flow of the oil inlet oil path 100 according to the oil pressure in the load feedback oil path 400. Specifically, referring to fig. 1, the main oil path 11 is connected to the oil return path 200 through the constant-pressure-difference pressure-reducing valve 13, and the load feedback oil path 400 is connected to the spring end of the constant-pressure-difference pressure-reducing valve 13, so that the maximum load pressure of each working link can act on the spring end of the constant-pressure-difference pressure-reducing valve 13, and when the load pressure becomes higher, the flow rate of oil shunted by the constant-pressure-reducing valve 13 from the main oil path 11 becomes lower, so that the flow rate of oil flowing into the oil inlet path 100 by the main oil path 11 becomes higher, the flow rate of oil flowing into the oil inlet path 100 is ensured to meet the requirement of the working link, and the actions of each actuator operate normally; when the load pressure is reduced, the oil flow required by the working connection is reduced, in order to avoid loss caused by the fact that redundant oil flow flows into the oil inlet oil way 100, the oil flow shunted from the main oil way 11 by the fixed differential pressure reducing valve 13 is increased, the flow of the oil inlet oil way 100 is reduced, the reduced flow of the oil inlet oil way 100 directly returns to the oil return oil way 200 through the fixed differential pressure reducing valve 13, the loss is reduced, and the purpose of energy conservation is achieved. The main oil path 11 is further provided with a main relief valve 15 connected to the return oil path 200, so as to ensure that the oil pressure of the inlet oil path 100 is always within a safe value range.

Further, referring to fig. 1, the oil inlet manifold 1 is provided with a load feedback unloading valve 14, the load feedback oil path 400 is connected to the oil unloading path 500 through the load feedback unloading valve 14, the load feedback unloading valve 14 is opened under the condition that each working manifold does not work, the load feedback unloading valve 14 is directly connected to the oil unloading path 500 for unloading, and the spring end of the constant differential pressure reducing valve 13 is not under the action of load pressure, so that oil in the main oil path 11 can be directly returned to the oil returning path 200 through the constant differential pressure reducing valve 13, and the oil loss of the oil inlet path 100 is reduced. And under the condition that the work units work, the load feedback unloading valve 14 is closed, the load pressure of each work unit can be fed back to the spring end of the constant-pressure-difference pressure-reducing valve 13 through the load feedback oil path 400 to adjust the flow of the oil inlet path 100, and when the oil pressure in the load feedback oil path 400 is too large and exceeds a safety value, the load feedback unloading valve 14 can directly overflow to the oil unloading path 500 for unloading, so that the operation safety of the hydraulic system is ensured. It should be noted that the load feedback unloading valve 14 is preferably an electromagnetic valve, and the electromagnet is powered on, the load feedback unloading valve 14 is closed, and the electromagnet is powered off, and the load feedback unloading valve 14 is opened.

In order to guide the maximum load pressure between the working couplings into the load feedback oil path 400, referring to fig. 1 and 2, the telescopic coupling 2 includes a telescopic main valve core 21 and a first shuttle valve 22, the main arm coupling 3 includes a second shuttle valve 35, the tower arm coupling 4 includes a tower arm main valve core 41 and a third shuttle valve 42, a comparison oil port of the third shuttle valve 42 is connected with an output oil port of the tower arm main valve core 41, two comparison oil ports of the second shuttle valve 35 are respectively connected with output oil ports of the main arm first oil path 34 and the third shuttle valve 42, two comparison oil ports of the first shuttle valve 22 are respectively connected with an output oil port of the second shuttle valve 35 and an output oil port of the telescopic main valve core 21, and an output oil port of the first shuttle valve 22 is connected with the load feedback oil path 400.

As a preferred embodiment of the hydraulic control system of the present invention, referring to fig. 1 and 2, the main arm control valve 32 includes a first main arm control valve 321 and a second main arm control valve 322, the main arm main valve core 31 includes a first main arm oil port c, a fourth main arm oil port h, a seventh main arm oil port k, a first main arm control oil port d and a second main arm control oil port g, the first main arm oil port c and the fourth main arm oil port h are connected to the first main arm oil path 34, the first main arm control oil port d is connected to the oil discharge oil path 500 through the second main arm oil path 36, the second main arm control oil port g is connected to the oil discharge oil path 500 through the third main arm oil path 37, the first main arm control valve 321 is disposed on the second main arm oil path 36, the second main arm control valve 322 is disposed on the third main arm oil path 37, the main arm first control oil port d is communicated with the main arm fourth oil port h when the main arm main valve core 31 is at the first working position, so that when the main arm main valve core 31 is blocked in the process of moving from the first working position to the middle position and the main arm main valve core 31 does not return to the middle position, oil flowing from the oil inlet oil path 100 to the main arm oil inlet p sequentially flows through the main arm first working oil port a, the main arm sixth oil port j, the main arm third oil port f, the main arm first oil path 34, the main arm fourth oil port h, the first control oil port d and the main arm first control valve 321 to unload the main arm oil unloading oil path 500, so that the working oil path of the main arm first working oil port a connected with the main arm oil cylinder rodless cavity cannot accumulate oil pressure, and uncontrollable stretching action of the main arm oil cylinder is avoided; the main arm second control oil port g is communicated with the main arm first oil port c when the main arm main valve core 31 is at the second working position, so that when clamping stagnation occurs in the process that the main arm main valve core 31 moves from the second working position to the middle position and the main arm main valve core 31 does not return to the middle position, oil flowing from the oil inlet oil path 100 to the main arm oil inlet p sequentially flows through the main arm second working oil port b, the main arm fifth oil port i, the main arm second oil port e, the main arm first oil path 34, the main arm first oil port c, the second control oil port g and the main arm second control valve 322 to unload the main arm oil unloading oil path 500, so that the working oil path connecting the main arm oil cylinder rod cavity with the main arm first working oil port a cannot accumulate oil pressure, and the inevitable retraction action of the main arm oil cylinder is avoided. In addition, the seventh port k of the main arm connected to the oil return path 200 is communicated with the fourth port h of the main arm when the main arm main valve core 31 is at the middle position, so that the control end of the main arm pressure compensating valve 33 is communicated with the oil return path 200 in the middle position state to directly unload.

It should be noted that, when the extending action and the retracting action of the main arm cylinder are uncontrollable, a safety problem may occur, and therefore the arrangement of the main arm first control valve 321 and the main arm second control valve 322 respectively corresponds to the two situations of the main arm main valve core 31 being stuck, and the actuator of the working link may cause a safety problem when one action is uncontrollable, and may not affect the other action when the other action is uncontrollable, for example, the retracting action of the telescopic cylinder (the actuator of the telescopic link 2) is safe for the aerial work platform, and even if the actuator is stuck, a safety hazard may not be caused, and the extending action of the telescopic cylinder may be uncontrollable, and therefore, only one control valve may be arranged in the telescopic link 2 to prevent the telescopic cylinder from generating uncontrollable extending action.

In order to ensure that the oil pressure delivered to the main arm oil cylinder by the main arm main valve core 31 is within a safe range, preferably, the main arm linkage 3 is provided with a main arm first overflow valve 38 and a main arm second overflow valve 39, the main arm first overflow valve 38 and the main arm first control valve 321 are connected in parallel on the main arm second oil path 36, the main arm main valve core 31 is in a first working position state, and when the oil pressure delivered to the main arm oil cylinder by a main arm first working oil port a exceeds a safe value, the hydraulic oil sequentially flows through a main arm sixth oil port j, a main arm third oil port f, a main arm first oil path 34, a main arm fourth oil port h and a main arm first control oil port d, so that the valve core of the main arm first overflow valve 38 is pushed open to unload to the oil unloading oil path 500; the main arm second overflow valve 39 and the main arm second control valve 322 are connected in parallel on the main arm third oil path 37, when the main arm main valve core 31 is in the second working position state, and the oil pressure delivered to the main arm oil cylinder by the main arm second working oil port b exceeds the safety value, the hydraulic oil flows through the main arm fifth oil port i, the main arm second oil port e, the main arm first oil path 34, the main arm first oil port c and the main arm second control oil port g in sequence, so as to jack the valve core of the main arm second overflow valve 39 to unload to the oil unloading oil path 500.

Referring to fig. 1, the control end of the main arm main valve core 31 is connected to the pilot oil passage 300 and the oil drain oil passage 500, and the main arm main valve core 31 is electromagnetically controlled, and preferably, the main arm first control valve 321 and the main arm second control valve 322 are also electromagnetically controlled. When the main arm main valve core 31 needs to move to a first working position, the main arm first electromagnet 311 is powered on, oil pressure in the pilot oil path 300 pushes the main arm main valve core 31 to move to the first working position, meanwhile, the electromagnet of the main arm first control valve 321 is powered on, the main arm first control valve 321 is closed, so that the oil inlet p of the main arm is blocked from the oil discharge oil path 500, the oil supply pressure of the main arm first working oil port a to the main arm oil cylinder rodless cavity is greater than a set value, and the main arm oil cylinder can extend out; when the main arm main valve core 31 needs to move to the second working position, the main arm second electromagnet 312 is powered on, the oil pressure in the pilot oil path 300 pushes the main arm main valve core 31 to move to the second working position, meanwhile, the electromagnet of the main arm second control valve 322 is powered on, the main arm second control valve 322 is closed, so that the oil inlet p of the main arm is blocked from the oil discharge oil path 500, the oil supply pressure of the main arm second working oil port b to the rod cavity of the main arm oil cylinder is greater than a set value, and the main arm oil cylinder can retract. When the main arm main valve core 31 receives a middle position instruction, the main arm first electromagnet 311 and the main arm second electromagnet 312 are not energized, the main arm main valve core 21 moves to the middle position under the action of a return spring at the control end, meanwhile, the electromagnets of the main arm first control valve 321 and the main arm second control valve 322 are not energized, and both the main arm first control valve 321 and the main arm second control valve 322 are in an open state, so that even if the main arm main valve core 31 is jammed and does not move to the middle position, for example, the main arm main valve core is jammed in the process of moving from the first working position to the middle position, or the main arm first control valve 321 and the main arm second control valve 322 are jammed in the process of moving from the second working position to the middle position, hydraulic oil input from the main arm oil inlet p can be directly unloaded from the main arm second oil path 36 or the main arm third oil path 37 to the oil unloading path 500, so that the oil pressure in the main arm first working oil port a or the main arm second working oil port b connected with the main arm oil cylinder does not exceed a set value, and under the action of the bidirectional balance valve, the main arm cylinder does not generate uncontrollable action under the action of the main arm cylinder.

The hydraulic control system of the invention connects the main valve core of the working connection with the oil unloading oil circuit 500 through the control valve, when the main valve core of the working connection moves to make one working oil port of the main valve core connect with the oil inlet, the control valve can connect with the oil inlet, thus making the oil inlet of the main valve core connect with the oil unloading oil circuit 500 through the control valve, and the control valve will open only when the main valve core of the working connection receives the middle control instruction, therefore, even if the main valve core is blocked and does not move to the middle position, the hydraulic oil which is delivered to the main valve core from the oil inlet of the oil inlet oil circuit can directly flow to the oil unloading oil circuit 500 through the control valve to release pressure, so that the hydraulic oil can not build enough pressure to be delivered to the actuator from the working oil port, and the actuator of the working connection can not generate uncontrollable action. When the actuator needs to be controlled to act in the working linkage, the main valve core is located at a working position, the control valve is closed at the moment, the oil inlet is blocked from the oil discharge oil path 500, and therefore hydraulic oil conveyed to the actuator from the working oil port by the main valve core has enough pressure, the actuator can enter and exit oil, and the actuator can complete action.

Further, the invention provides an aerial work machine, which comprises the hydraulic control system, so that all the beneficial effects of the hydraulic control system are achieved, and the details are not repeated herein.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (10)

1. A hydraulic control system is characterized by comprising an oil inlet oil way (100), an oil return way (200), an oil unloading oil way (500), an oil inlet joint (1) and a plurality of working joints, wherein the oil inlet oil way (100) is connected with the oil inlet joint (1) and each working joint so as to supply oil, the oil return way (200) is connected with the oil inlet joint (1) and each working joint so as to return oil, a main valve core of the working joint comprises an oil inlet connected with the oil inlet oil way (100), an oil return port connected with the oil return way (200) and two working oil ports respectively connected with an actuator, and when the oil supply pressure of the actuator is lower than a set value, the actuator does not act, wherein part or all of the working joints are provided with control valves respectively connected with the main valve cores of the working joints and the oil unloading oil way (500), when the main valve cores of the working joints move to enable one of the working oil ports of the main valve cores of the working joints to be connected with the oil inlet, the control valves can be connected with the oil inlet, and when the middle valve core of the working joint receives a control instruction, the main valve can control the oil unloading oil way (500) to be communicated with the oil way.

2. A hydraulic control system according to claim 1, characterized in that each said working link comprises a telescopic link (2), a main arm link (3) and a tower arm link (4), said telescopic link (2), said main arm link (3) and said tower arm link (4) being provided with said control valve.

3. The hydraulic control system according to claim 2, wherein the main arm linkage (3) comprises a main arm main valve core (31) and a main arm control valve (32), the main arm control valve (32) is respectively connected with the main arm main valve core (31) and the oil discharge path (500), the main arm main valve core (31) comprises a main arm oil inlet (p), a main arm oil return port (t), a main arm first working oil port (a) and a main arm second working oil port (b), the main arm main valve core (31) at least comprises a first working position, a second working position and a middle position, the main arm oil inlet (p) is communicated with the main arm first working oil port (a) in the first working position state of the main arm main valve core (31), and the main arm oil return port (t) is communicated with the main arm second working oil port (b); when the main arm main valve core (31) is in a second working position state, the main arm oil inlet (p) is communicated with the main arm second working oil port (b), and the main arm oil return port (t) is communicated with the main arm first working oil port (a); the main arm main valve core (31) has a Y-shaped middle function;

when the main arm main valve core (31) is in a first working position or a second working position, the main arm control valve (32) is connected with the main arm oil inlet (p), and when the main arm main valve core (31) receives a middle position instruction, the main arm control valve (32) can control the main arm main valve core (31) to be communicated with the oil unloading oil way (500).

4. The hydraulic control system as claimed in claim 3, wherein the main arm linkage (3) is provided with a main arm pressure compensation valve (33), the oil inlet passage (100) is connected to the main arm oil inlet (p) through the main arm pressure compensation valve (33), the main arm main valve core (31) comprises a main arm second oil port (e), a main arm third oil port (f), a main arm fifth oil port (i) and a main arm sixth oil port (j), the main arm fifth oil port (i) is connected to the main arm second working oil port (b), the main arm sixth oil port (j) is connected to the main arm first working oil port (a), the main arm second oil port (e) and the main arm third oil port (f) are jointly connected to the control end of the main arm pressure compensation valve (33) through a main arm first oil passage (34), and the main arm sixth oil port (j) is communicated with the main arm third oil port (f) when the main arm core (31) is at the first working position, and the main arm second oil port (e) is communicated with the main arm third oil port (f) at the second working position of the main arm core (31).

5. The hydraulic control system according to claim 4, characterized by comprising a load feedback oil path (400), wherein the output pressure of the main valve core of each working connection can be led into the load feedback oil path (400), the oil inlet connection (1) is provided with a constant-differential pressure reducing valve (13), and the constant-differential pressure reducing valve (13) can control the oil flow of the oil inlet path (100) according to the oil pressure in the load feedback oil path (400).

6. The hydraulic control system according to claim 5, wherein the telescopic link (2) comprises a telescopic main valve core (21) and a first shuttle valve (22), the main arm link (3) comprises a second shuttle valve (35), the tower arm link (4) comprises a tower arm main valve core (41) and a third shuttle valve (42), a comparison oil port of the third shuttle valve (42) is connected with an output oil port of the tower arm main valve core (41), two comparison oil ports of the second shuttle valve (35) are respectively connected with the main arm first oil path (34) and an output oil port of the third shuttle valve (42), two comparison oil ports of the first shuttle valve (22) are respectively connected with an output oil port of the second shuttle valve (35) and an output oil port of the telescopic main valve core (21), and an output oil port of the first shuttle valve (22) is connected with the load feedback oil path (400).

7. The hydraulic control system as claimed in claim 4, wherein the main arm control valve (32) comprises a first main arm control valve (321) and a second main arm control valve (322), the main arm main valve core (31) comprises a first main arm oil port (c), a fourth main arm oil port (h), a seventh main arm oil port (k), a first main arm control oil port (d) and a second main arm control oil port (g), the first main arm oil port (c) and the fourth main arm oil port (h) are all connected with the first main arm oil path (34), the first main arm control oil port (d) is connected with the oil unloading oil path (500) through a second main arm oil path (36), the second main arm control oil port (g) is connected with the oil unloading path (500) through a third main arm oil path (37), the first main arm control valve (321) is arranged on the second main arm oil path (36), the second main arm control valve (322) is arranged on the third main arm oil path (37), the first main arm control oil port (d) is connected with the fourth main arm oil port (h) when the first main arm oil port (c) is connected with the second main arm oil port (31) and the second main arm oil port (h), and the second main arm oil port (31) is connected with the second main arm oil port (d) when the first main arm oil port (c) is connected with the second main arm oil port (31) when the second main arm oil port (31) is in the second main arm oil port (h), the position, the second main arm oil port (c) is connected with the second main arm oil port (31), the second control oil port (c), the second control oil port (d) and the second control valve (31) is connected with the second control oil port (c), and the second control oil port (31) is connected with the second control oil port (h), and the second control valve (d) when the second main arm oil port (d) is connected with the second main arm oil port (31) when the second main arm oil port (d) and the second main arm oil port (31) is connected with the second control valve (d), the second control valve (31) is connected with the first main arm oil port (31) when the first main arm oil port (c) when the second control oil port (c) and the second control valve (h), the first main arm oil port (h), the second control valve (31) is connected with the second control valve (31) when the first control oil port (c) is connected with the second control valve (d) and the second control oil port (31) when the second control oil port (d) is connected with the second control valve (31) is connected with the first control valve (c) and the second control oil port (d) and the first main arm oil port (h), the second control oil port (31) is connected with the first control oil port (h), the second control oil port (c) and the second control oil port (31) when the second control oil port (31) and the first main arm oil port (h), the second control valve (c) is connected with the second control valve is connected with the second control oil port (c) when the second control valve (31) when the second control valve is connected with the second control valve (c) when the second control oil port (c) when the second control valve (31) when the second control valve is connected with the second control oil port (31) when the second control ) When the main arm main valve core (31) is in a neutral position, the main arm main valve core is communicated with the main arm main valve core.

8. The hydraulic control system according to claim 7, wherein the main arm linkage (3) is provided with a main arm first relief valve (38) and a main arm second relief valve (39), the main arm first relief valve (38) and the main arm first control valve (321) are connected in parallel to the main arm second oil passage (36), and the main arm second relief valve (39) and the main arm second control valve (322) are connected in parallel to the main arm third oil passage (37).

9. The hydraulic control system according to claims 1 to 8, wherein part or all of the working units are provided with a bidirectional balance valve, two working oil ports of the working units are respectively connected with two oil inlets of the bidirectional balance valve in a one-to-one correspondence manner, and two oil outlets of the bidirectional balance valve are respectively connected with the actuator.

10. An aerial work machine comprising a hydraulic control system as claimed in any one of claims 1 to 9.

Images