Hydraulic system and engineering machinery controlled by a hybrid control of a proportional valve and a switch valve

Abstract

The invention discloses a proportional valve and switch valve hybrid control hydraulic system and engineering machinery, comprising: a single-double pump switching control valve group, in a first position state, the first pressure oil port is connected with the first working oil port and the second working oil port, and the second pressure oil port is connected with the third working oil port and the fourth working oil port; in a second position state, the first pressure oil port is connected with the first working oil port, and the second pressure oil port is connected with the third working oil port; a first variable pump is connected with the first pressure oil port; a second variable pump is connected with the second pressure oil port; a proportional valve group comprises a first oil inlet connected with the first working oil port and a second oil inlet connected with the fourth working oil port; a switch valve group comprises a third oil inlet connected with the second working oil port and the third working oil port; an Ls on-off control valve is used to connect or disconnect the load feedback oil circuits of the first variable pump and the second variable pump, and the actuator has a compound action with low cost.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic control technology, and more specifically, to a proportional valve and switch valve mixed control hydraulic system. In addition, the present invention also relates to an engineering machine comprising the proportional valve and switch valve mixed control hydraulic system. Background Art

[0002] In construction machinery, hydraulic systems are often used to control the movement of actuators.

[0003] In the hydraulic system control circuit of the related technology, if the actuator requires different speeds according to the actual working conditions during operation, a proportional valve and a variable pump are combined to form a hydraulic control system that meets the requirements; if the actuator does not require proportional speed changes during operation, a switch valve and a fixed displacement pump are combined to form a hydraulic control system that meets the requirements; when the actuator whose speed requires proportional adjustment and the actuator whose speed does not require proportional adjustment perform compound actions at the same time, either a hydraulic control system composed of a proportional valve and a variable displacement pump can be used to meet the requirements, or a hydraulic control system composed of a proportional valve and a variable displacement pump and a hydraulic control system composed of a switch valve and a fixed displacement pump need to be configured at the same time, and the two hydraulic control systems are used together to meet the action requirements of the actuator.

[0004] When all proportional valves and variable displacement pumps are used, the cost of the hydraulic control system is high due to the high procurement cost of the proportional valves; when both a hydraulic control system that uses a proportional valve and a variable displacement pump and a hydraulic control system that uses a switch valve and a metering pump are configured, an additional metering pump is required, which also results in high cost of the hydraulic control system.

[0005] Therefore, how to reduce the cost of the hydraulic control system when an actuator whose speed requires proportional adjustment and an actuator whose speed does not require proportional adjustment perform compound actions at the same time is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a proportional valve and switch valve hybrid control hydraulic system, which can realize the simultaneous compound action of the actuator whose speed requires proportional adjustment and the actuator whose speed does not require proportional adjustment, and the hydraulic control system has low cost.

[0007] Another object of the present invention is to provide an engineering machinery including the above-mentioned proportional valve and switch valve mixed control hydraulic system, which can realize the simultaneous compound action of the actuator whose speed requires proportional adjustment and the actuator whose speed does not require proportional adjustment, and has low cost.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A proportional valve and switch valve hybrid control hydraulic system, comprising:

[0010] The single-double pump switching control valve group includes a first pressure oil port, a second pressure oil port, a first working oil port, a second working oil port, a third working oil port and a fourth working oil port, and can be switched between a first position state and a second position state. When the single-double pump switching control valve group is in the first position state, the first pressure oil port is communicated with the first working oil port and the second working oil port respectively, and the second pressure oil port is communicated with the third working oil port and the fourth working oil port respectively; when the single-double pump switching control valve group is in the second position state, the first pressure oil port is communicated with the first working oil port, and the second pressure oil port is communicated with the third working oil port;

[0011] A first variable displacement pump connected to the first pressure oil port;

[0012] A second variable displacement pump connected to the second pressure oil port;

[0013] A proportional valve group, used for controlling the first actuator to perform stepless speed regulation, comprising a first oil inlet and a second oil inlet, wherein the first oil inlet is connected to the first working oil port, and the second oil inlet is connected to the fourth working oil port;

[0014] A switch valve group, used for controlling the second actuator to work at a constant speed, comprising a third oil inlet, wherein the third oil inlet is connected to the second working oil port and the third working oil port respectively;

[0015] The Ls on-off control valve is respectively connected to the load-sensitive Ls port of the proportional valve group, the pressure oil port of the second variable pump, the control oil port of the first variable pump and the control oil port of the second variable pump. When the single-double pump switching control valve group is in the first position state, the Ls on-off control valve is in the on state, so that the load feedback oil circuits of the first variable pump and the second variable pump are connected; when the single-double pump switching control valve group is in the second position state, the Ls on-off control valve is in the off state, so that the load feedback oil circuits of the first variable pump and the second variable pump are disconnected. Optionally, it also includes:

[0016] A first pressure sensor, used for detecting the oil circuit pressure for controlling the action of the first actuator;

[0017] A second pressure sensor, used for detecting the oil circuit pressure for controlling the action of the second actuator;

[0018] The solenoid valve is connected between the single-double pump switching control valve group and the pilot oil circuit. When the single-double pump switching control valve group is in the first position state, the solenoid valve is disconnected; when the first pressure sensor and the second pressure sensor detect pressure signals at the same time, the solenoid valve is turned on, so that under the action of the pilot oil circuit, the single-double pump switching control valve group is switched from the first position state to the second position state.

[0019] Optionally, it also includes:

[0020] At least two pilot handles, connected to the pilot oil circuit, for respectively controlling the actions of the first actuator and the second actuator;

[0021] A shuttle valve group connected to the control oil circuit of each pilot handle, and used for outputting the pressure of the corresponding control oil circuit when the pilot handle is opened;

[0022] The first pressure sensor and the second pressure sensor are respectively connected to outlets of the shuttle valve group.

[0023] Optionally, the pilot control port of the Ls on-off control valve is connected to the working oil port of the solenoid valve, so as to control the position switching of the Ls on-off control valve by the on-off power of the solenoid valve.

[0024] Optionally, it also includes:

[0025] A relief valve group, provided between the single-pump and double-pump switching control valve group and the switch valve group, and used to set the maximum pressure when the switch valve group is working;

[0026] The third oil inlet is connected to the second working oil port and the third working oil port respectively through the relief valve group;

[0027] The Ls on-off control valve is connected to the pressure oil port of the second variable pump via the high-pressure signal Px port of the relief valve group.

[0028] Optionally, it also includes:

[0029] The hydraulically controlled stop valve is used to set different system pressures for the overflow valve group when the number of the switch valve groups is at least two and the second actuator corresponding to different switch valve groups is actuated.

[0030] Optionally, it also includes:

[0031] A first isolation valve, whose pressure port is connected to the high-pressure signal Px port, a working oil port of the first isolation valve is connected to the load sensing port X of the second variable pump, and is connected to the load sensing port X of the first variable pump through the Ls on-off control valve;

[0032] The first isolation valve includes at least one first pilot oil port, the number of the first pilot oil ports is the same as the number of the switch valve groups, and the first pilot oil ports are connected to the switch valve groups in a one-to-one correspondence. When any one of the switch valve groups is working, the pressure port of the first isolation valve is connected to its working oil port; when only the proportional valve group is working, the pressure port of the first isolation valve is disconnected from its working oil port.

[0033] Optionally, it also includes:

[0034] The second isolation valve, whose working oil port is respectively connected with the pressure port of the first isolation valve and the high-pressure signal Px port, includes at least one second pilot oil port. The number of the second pilot oil ports is the same as the number of the proportional valve groups, and the second pilot oil ports are connected with the load-sensitive Ls ports of the proportional valve groups in a one-to-one correspondence. When any one of the proportional valve groups is working, the pressure port of the second isolation valve is connected with its working oil port; when only the switch valve group is working, the pressure port of the second isolation valve is disconnected from its working oil port.

[0035] Optionally, it also includes:

[0036] The first one-way valve is arranged between the working oil port of the first isolation valve and the load sensing port X of the second variable pump.

[0037] Optionally, it also includes:

[0038] A second one-way valve is provided between the first variable pump and the first pressure oil port;

[0039] The third one-way valve is arranged between the second variable pump and the second pressure oil port.

[0040] An engineering machine comprises a hybrid control hydraulic system of any one of the above-mentioned proportional valves and a switch valve.

[0041] The proportional valve and switch valve hybrid control hydraulic system provided by the present invention has the following beneficial effects:

[0042] When the first actuator controlled by the proportional valve group and the second actuator controlled by the switch valve group perform a compound action, the single-double pump switching control valve group is in the second position state. At this time, the Ls on-off control valve is disconnected, so that the load feedback oil circuit of the first variable pump and the second variable pump is disconnected, that is, the connection of the Ls feedback oil circuit between the proportional valve group and the switch valve group is cut off. At this time, the first variable pump, the single-double pump switching control valve group and the proportional valve group form a load-sensitive system. The hydraulic oil of the first variable pump flows into the first pressure oil port of the single-double pump switching control valve group, passes through the single-double pump switching control valve group, flows out from the first working oil port of the single-double pump switching control valve group, and then flows into the first oil inlet of the proportional valve group, so that the first actuator controlled by the proportional valve group can be steplessly adjusted, and is not affected by the change of load size, nor by the load size of the second actuator controlled by the switch valve group. The second variable pump, the single-double pump switching control valve group, the overflow valve group and the switch valve group form a switch valve control system. At this time, the second variable pump is at the maximum displacement, which is equivalent to using the second variable pump as a fixed displacement pump. The hydraulic oil provided by the second variable pump flows to the second actuator controlled by the switch valve group. The speed of the second actuator controlled by the switch valve group is not affected by the load size of the first actuator controlled by the proportional valve group. Thus, the first actuator controlled by the proportional valve group and the second actuator controlled by the switch valve group can perform good composite actions, so that the proportional valve group and the switch valve group are not affected by their respective load sizes or load changes.

[0043] It can be seen that the proportional valve and the switch valve mixed control hydraulic system realizes the effective compound action between the first actuator controlled by the proportional valve group and the second actuator controlled by the switch valve group. Avoid using the hydraulic control system that is entirely composed of proportional valves and variable pumps. In many occasions where stepless speed regulation is not required, the switch valve group is directly used to control the action of the second actuator, which reduces the cost of purchasing proportional valves; at the same time, good compound action can be achieved without adding additional quantitative pumps, which can greatly reduce the cost of the hydraulic control system.

[0044] The engineering machinery provided by the present invention includes the above-mentioned proportional valve and switch valve mixed control hydraulic system and has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0046] Figure 1A schematic diagram of a proportional valve and a switch valve hybrid control hydraulic system provided by a specific embodiment of the present invention;

[0047] Figure 2 for Figure 1 A partial enlarged view of the single-dual pump switching control valve group, the Ls on-off control valve, the solenoid valve, the first variable pump and the second variable pump;

[0048] Figure 3 It is a partial enlarged view of the hydraulically controlled stop valve, the first isolation valve, the second isolation valve and the relief valve group;

[0049] Figure 4 It is a partial enlarged view of the proportional valve group and the switch valve group;

[0050] Figure 5 It is a partial enlarged view of the pilot handle, shuttle valve group, first pressure sensor and second pressure sensor.

[0051] Reference numerals:

[0052] 1-single and double pump switching control valve group; 2-first variable pump; 3-second variable pump; 4-proportional valve group; 5-switching valve group; 51-first switching valve group; 52-second switching valve group; 6-overflow valve group; 61-first overflow valve; 62-second overflow valve; 7-Ls on-off control valve; 8-first pressure sensor; 9-second pressure sensor; 10-solenoid valve; 11-pilot handle; 12-shuttle valve group; 13-hydraulic stop valve; 14-first isolation valve; 15-second isolation valve; 16-first one-way valve; 17-second one-way valve; 18-third one-way valve; 19-pilot pump; 20-pilot oil source control valve; 21-first actuator; 22-second actuator. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] The core of the present invention is to provide a proportional valve and switch valve hybrid control hydraulic system, which can realize the composite action of the actuator whose speed needs to be proportionally adjusted and the actuator whose speed does not need to be proportionally adjusted at the same time, and the cost of the hydraulic control system is low. Another core of the present invention is to provide an engineering machinery including the above-mentioned proportional valve and switch valve hybrid control hydraulic system, which can realize the composite action of the actuator whose speed needs to be proportionally adjusted and the actuator whose speed does not need to be proportionally adjusted at the same time, and the cost is low.

[0055] Please combine Figures 1 to 5 The embodiment of the present invention provides a proportional valve and switch valve hybrid control hydraulic system, including a single-double pump switching control valve group 1, a first variable pump 2, a second variable pump 3, a proportional valve group 4, a switch valve group 5 and an Ls on-off control valve 7. The single-double pump switching control valve group 1 includes a first pressure oil port P1, a second pressure oil port P2, a first working oil port A1, a second working oil port B1, a third working oil port A2 and a fourth working oil port B2. The single-double pump switching control valve group 1 can be switched between a first position state and a second position state. When the single-double pump switching control valve group 1 is in the first position state, the first pressure oil port P1 is connected to the first working oil port A1 and the second working oil port B1 respectively, and the second pressure oil port P2 is connected to the third working oil port A2 and the fourth working oil port B2 respectively; when the single-double pump switching control valve group 1 is in the first position state, the first pressure oil port P1 is connected to the first working oil port A1 and the second working oil port B1 respectively, and the second pressure oil port P2 is connected to the third working oil port A2 and the fourth working oil port B2 respectively; when the single-double pump switching control valve group 1 is in In the second position state, the first pressure oil port P1 is connected to the first working oil port A1, and the second pressure oil port P2 is connected to the third working oil port A2; the first variable pump 2 is connected to the first pressure oil port P1; the second variable pump 3 is connected to the second pressure oil port P2; the proportional valve group 4 is used to control the first actuator 21 to perform stepless speed regulation, the proportional valve group 4 includes a first oil inlet P1 and a second oil inlet P2, the first oil inlet P1 is connected to the first working oil port A1 of the single-double pump switching control valve group 1, and the second oil inlet P2 is connected to the fourth working oil port B2 of the single-double pump switching control valve group 1; the switch valve group 5 is used to control the second actuator 22 to work at a constant speed, the switch valve group 5 includes a third oil inlet P, and the third oil inlet P is respectively connected to the second working oil port B1 and the third working oil port A2 of the single-double pump switching control valve group 1; The Ls on-off control valve 7 is respectively connected to the load-sensitive Ls port of the proportional valve group 4, the pressure oil port of the second variable pump 3, the control oil port of the first variable pump 2 and the control oil port of the second variable pump 3. When the single-double pump switching control valve group 1 is in the first position state, the Ls on-off control valve 7 is in the on state, so that the load feedback oil circuits of the first variable pump 2 and the second variable pump 3 are connected; when the single-double pump switching control valve group 1 is in the second position state, the Ls on-off control valve 7 is in the off state, so that the load feedback oil circuits of the first variable pump 2 and the second variable pump 3 are disconnected.

[0056] When only the first actuator 21 controlled by the proportional valve group 4 is in motion, the single-double pump switching control valve group 1 is in the first position state. At this time, the first variable pump 2, the second variable pump 3, the single-double pump switching control valve group 1, the proportional valve group 4 and the Ls on-off control valve 7 form a load-sensitive hydraulic system. The hydraulic oil of the first variable pump 2 flows into the first pressure oil port P1 of the single-double pump switching control valve group 1, passes through the single-double pump switching control valve group 1, and flows out from the first working oil port A1 of the single-double pump switching control valve group 1 (because the second actuator 22 controlled by the switch valve group 5 does not act at this time, it is equivalent to having a blocking function for the second working oil port B1 of the single-double pump switching control valve group 1. Therefore, even when the single-double pump switching control valve group 1 is in the first position state, the hydraulic oil of the first variable pump 2 flows into the first pressure oil port P1 of the single-double pump switching control valve group 1, passes through the single-double pump switching control valve group 1, and flows out from the first working oil port A1 of the single-double pump switching control valve group 1). In the state, the second working oil port B1 is connected with the first pressure oil port P1, and the hydraulic oil flowing into the first pressure oil port P1 will not flow out from the second working oil port B1, but from the first working oil port A1), and then flow into the first oil inlet P1 of the proportional valve group 4, the hydraulic oil of the second variable pump 3 flows into the second pressure oil port P2 of the single-double pump switching control valve group 1, and after passing through the single-double pump switching control valve group 1, it flows out from the fourth working oil port B2 of the single-double pump switching control valve group 1, and then flows into the second oil inlet P2 of the proportional valve group 4, that is, the hydraulic oil required by the proportional valve group 4 all comes from the first variable pump 2 and the second variable pump 3, and the proportional valve group 4 provides flow according to the speed required by the first actuator 21 to control the first actuator 21 to achieve stepless speed regulation.

[0057] When only the second actuator 22 controlled by the switch valve group 5 is in motion, the single-double pump switching control valve group 1 is in the first position state. At this time, the first variable pump 2, the second variable pump 3, the single-double pump switching control valve group 1, the switch valve group 5 and the Ls on-off control valve 7 form a switch valve control system. At this time, the first variable pump 2 and the second variable pump 3 can be both at the maximum displacement, which is equivalent to using the first variable pump 2 and the second variable pump 3 as two fixed displacement pumps. The hydraulic oil of the first variable pump 2 flows into the first pressure oil port P1 of the single-double pump switching control valve group 1, passes through the single-double pump switching control valve group 1, and flows out from the second working oil port B1 of the single-double pump switching control valve group 1 (because the first actuator 21 controlled by the proportional valve group 4 is not in motion at this time, which is equivalent to the single-double pump switching control valve group 4). The first working oil port A1 of the control valve group 1 has a blocking function. Therefore, even when the first working oil port A1 is connected to the first pressure oil port P1 when the single-double pump switching control valve group 1 is in the first position state, the hydraulic oil flowing into the first pressure oil port P1 will not flow out from the first working oil port A1, but from the second working oil port B1), and then flow into the third oil inlet P of the switch valve group 5. The hydraulic oil of the second variable pump 3 flows into the second pressure oil port P2 of the single-double pump switching control valve group 1, and after passing through the single-double pump switching control valve group 1, flows out from the third working oil port A2 of the single-double pump switching control valve group 1, and then flows into the third oil inlet P of the switch valve group 5. That is, the hydraulic oil of the first variable pump 2 and the second variable pump 3 both flow to the second actuator 22 controlled by the switch valve group 5.

[0058] When the first actuator 21 controlled by the proportional valve group 4 and the second actuator 22 controlled by the switch valve group 5 perform a compound action, the single-double pump switching control valve group 1 is in the second position state. At this time, the Ls on-off control valve 7 is disconnected, so that the load feedback oil circuits of the first variable pump 2 and the second variable pump 3 are disconnected, that is, the connection of the Ls feedback oil circuit between the proportional valve group 4 and the switch valve group 5 is cut off. At this time, the first variable pump 2, the single-double pump switching control valve group 1 and the proportional valve group 4 form a load-sensitive system, and the hydraulic oil of the first variable pump 2 flows into the first pressure oil port P1 of the single-double pump switching control valve group 1, passes through the single-double pump switching control valve group 1, flows out from the first working oil port A1 of the single-double pump switching control valve group 1, and then flows into the first oil inlet P1 of the proportional valve group 4, so that the first actuator 21 controlled by the proportional valve group 4 can be steplessly adjusted, and is not affected by the change of load size, nor by the load size of the second actuator 22 controlled by the switch valve group 5. The second variable pump 3, the single-pump and double-pump switching control valve group 1, and the switch valve group 5 form a switch valve control system. At this time, the second variable pump 3 is at the maximum displacement, which is equivalent to using the second variable pump 3 as a fixed displacement pump. The hydraulic oil of the second variable pump 3 flows into the second pressure oil port P2 of the single-pump and double-pump switching control valve group 1, passes through the single-pump and double-pump switching control valve group 1, flows out from the third working oil port A2 of the single-pump and double-pump switching control valve group 1, and then flows into the first oil inlet P1 of the proportional valve group 4, and then flows into the third oil inlet P of the switch valve group 5, that is, the hydraulic oil provided by the second variable pump 3 flows to the second actuator 22 controlled by the switch valve group 5, and the speed of the second actuator 22 controlled by the switch valve group 5 is not affected by the load size of the first actuator 21 controlled by the proportional valve group 4. In this way, the first actuator 21 controlled by the proportional valve group 4 and the second actuator 22 controlled by the switch valve group 5 can perform good compound actions, so that the proportional valve group 4 and the switch valve group 5 are not affected by their respective load sizes or load changes.

[0059] It can be seen that the proportional valve and the switch valve mixed control hydraulic system realizes the effective compound action between the first actuator 21 controlled by the proportional valve group 4 and the second actuator 22 controlled by the switch valve group 5. Avoid using the hydraulic control system that is entirely composed of proportional valves and variable pumps. In many occasions where stepless speed regulation is not required, the switch valve group 5 is directly used to control the action of the second actuator 22, which reduces the cost of purchasing proportional valves; at the same time, good compound action can be achieved without adding additional quantitative pumps, which can greatly reduce the cost of the hydraulic control system.

[0060] In order to realize the automatic switching of the single-pump and double-pump switching control valve group 1 from the first position to the second position, please combine Figure 1 , Figure 2 and Figure 5In some embodiments, the proportional valve and switch valve mixed control hydraulic system also includes a first pressure sensor 8, a second pressure sensor 9 and a solenoid valve 10. The first pressure sensor 8 is used to detect the oil circuit pressure for controlling the action of the first actuator 21; the second pressure sensor 9 is used to detect the oil circuit pressure for controlling the action of the second actuator 22; the solenoid valve 10 is connected between the single-double pump switching control valve group 1 and the pilot oil circuit. When the single-double pump switching control valve group 1 is in the first position state, the solenoid valve 10 is disconnected; when the first pressure sensor 8 and the second pressure sensor 9 detect pressure signals at the same time, the solenoid valve 10 is turned on, so that the single-double pump switching control valve group 1 is switched from the first position state to the second position state under the action of the pilot oil circuit.

[0061] That is to say, this embodiment uses the on and off of the solenoid valve 10 to automatically control the switching of the two position states of the single-double pump switching control valve group 1, and uses the pressure signal detected by the first pressure sensor 8 and the second pressure sensor 9 to control the on and off of the solenoid valve 10. When the first pressure sensor 8 and the second pressure sensor 9 detect the pressure signal at the same time, it indicates that the first actuator 21 and the second actuator 22 perform a compound action. At this time, the solenoid valve 10 is energized and connected, so that the single-double pump switching control valve group 1 is connected to the pilot oil circuit, so that the single-double pump switching control valve group 1 is switched from the first position state to the second position state by using the pilot pressure. Similarly, it can be understood that when only one of the first pressure sensor 8 and the second pressure sensor 9 detects the pressure signal, it indicates that only the first actuator 21 is working alone or only the second actuator 22 is working alone. At this time, the solenoid valve 10 is powered off, so that the single-double pump switching control valve group 1 is disconnected from the pilot oil circuit, so that the single-double pump switching control valve group 1 is switched from the second position state to the first position state.

[0062] For further information, please refer to Figure 1 In some embodiments, the pilot oil circuit includes a pilot pump 19 and a pilot oil source control valve 20 . The pilot pump 19 is used to provide pilot control oil, and the pilot oil source control valve 20 is connected to the pilot pump 19 .

[0063] In addition, in order to facilitate the position state switching of the Ls on-off control valve 7, please refer to Figure 2In some embodiments, the pilot control port of the Ls on-off control valve 7 is connected to the working oil port of the solenoid valve 10, so that the Ls on-off control valve 7 is switched in position by the on-off power of the solenoid valve 10. That is to say, when the solenoid valve 10 is powered on, the single-double pump switching control valve group 1 and the Ls on-off control valve 7 are switched at the same time, so that the single-double pump switching control valve group 1 is switched from the first position state to the second position state, and the Ls on-off control valve 7 is switched from the on state to the off state, that is, when the solenoid valve 10 is powered on, the Ls on-off control valve 7 is connected to the pilot oil circuit, so that the pilot pressure can be used to realize the switching of the Ls on-off control valve 7 from the on state to the off state.

[0064] It can be seen that in the above embodiments, the single-double pump switching control valve group 1 and the Ls on-off control valve 7 are hydraulically controlled pilot valves. Of course, in other embodiments, the single-double pump switching control valve group 1 and the Ls on-off control valve 7 can also be electrically controlled pilot valves.

[0065] For further information, please refer to Figure 5 In some embodiments, the proportional valve and switch valve mixed control hydraulic system also includes at least two pilot handles 11 and a shuttle valve group 12. The pilot handle 11 is connected to the pilot oil circuit for controlling the actions of the first actuator 21 and the second actuator 22 respectively; the shuttle valve group 12 is connected to the control oil circuit of each pilot handle 11 for outputting the pressure of the corresponding control oil circuit when the pilot handle 11 is opened; the first pressure sensor 8 and the second pressure sensor 9 are respectively connected to the outlet of the shuttle valve group 12.

[0066] That is to say, in this embodiment, by setting the shuttle valve group 12, the first pressure sensor 8 and the second pressure sensor 9 respectively detect the pressure values ​​at different outlets of the shuttle valve group 12, so as to sense the pressure of the control oil circuit used to control the action of the first actuator 21 and / or the second actuator 22, thereby determining whether the proportional valve group 4 and the switch valve group 5 are acting simultaneously.

[0067] In addition, please combine Figure 1 and Figure 3 In some embodiments, the proportional valve and switch valve hybrid control hydraulic system further includes a relief valve group 6, which is arranged between the single-double pump switching control valve group 1 and the switch valve group 5, and is used to set the maximum pressure when the switch valve group 5 is working; the third oil inlet is connected to the second working oil port and the third working oil port respectively through the relief valve group 6; the Ls on-off control valve 7 is connected to the pressure oil port of the second variable pump 3 through the high pressure signal Px port of the relief valve group 6. In other words, the maximum pressure of the switch valve group 5 is set by the relief valve group 6.

[0068] In addition, please combine Figure 1 and Figure 3In some embodiments, the proportional valve and switch valve mixed control hydraulic system also includes a hydraulically controlled stop valve 13. The hydraulically controlled stop valve 13 is used to set different system pressures for the overflow valve group 6 when the number of the switch valve groups 5 is at least two and the second actuator 22 corresponding to different switch valve groups 5 is actuated.

[0069] That is to say, the number of the switch valve groups 5 can be one or at least two. When the number of the switch valve groups 5 is at least two, the overflow valve group 6 can set the maximum pressure for different switch valve groups 5. In this embodiment, the hydraulically controlled stop valve 13 is set to control the overflow valve group 6 to perform graded setting of the maximum pressure of different switch valve groups 5 when they are working.

[0070] For example, when the number of the switch valve groups 5 is two, for the convenience of description, the two switch valve groups 5 are respectively referred to as the first switch valve group 51 and the second switch valve group 52. At this time, the overflow valve group 6 may include two overflow valves, namely the first overflow valve 61 and the second overflow valve 62. The first overflow valve 61 is used to set the maximum pressure when the first switch valve group 51 is working, and the second overflow valve 62 is used to set the maximum pressure when the second switch valve group 52 is working. The number of the hydraulically controlled stop valve 13 is one, and the hydraulically controlled stop valve 13 is respectively connected to the pilot oil circuit, the overflow valve group 6 and the second switch valve group 52. When the second actuator 22 corresponding to the first switch valve group 51 is actuated, the hydraulically controlled stop valve 13 is in a conducting state. At this time, the first overflow valve 61 sets the maximum pressure when the first switch valve group 51 is working; when the second actuator 22 corresponding to the second switch valve group 52 is actuated, the hydraulically controlled stop valve 13 is in a cut-off state. At this time, the second overflow valve 62 sets the maximum pressure of the second switch valve group 52.

[0071] It should be noted that when the number of switch valve groups 5 is at least three, the number of hydraulically controlled stop valves 13 can be increased accordingly, and by reasonably designing the oil circuit connection of the hydraulically controlled stop valve 13, the hydraulically controlled stop valve 13 can realize graded setting of the maximum pressure of the overflow valve group 6 when different switch valve groups 5 are working.

[0072] Also, please continue to combine Figure 1 and Figure 3In some embodiments, the proportional valve and switch valve mixed control hydraulic system further includes a first isolation valve 14, the pressure port P of the first isolation valve 14 is connected to the high pressure signal Px port of the overflow valve group 6, the working oil port A of the first isolation valve 14 is connected to the load sensing port X of the second variable pump 3, and is connected to the load sensing port X of the first variable pump 2 through the Ls on-off control valve 7; the first isolation valve 14 includes at least one first pilot oil port, the number of the first pilot oil ports is the same as the number of the switch valve group 5, and the first pilot oil port is connected to the switch valve group 5 in a one-to-one correspondence. When any one of the switch valve groups 5 is working, the pressure port of the first isolation valve 14 is connected to its working oil port; when only the proportional valve group 4 is working, the pressure port of the first isolation valve 14 is disconnected from its working oil port. For example, when the number of switch valve groups 5 is two, the two switch valve groups 5 are respectively the first switch valve group 51 and the second switch valve group 52. At this time, the first isolation valve 14 includes two first pilot oil ports, namely the first pilot oil port a and the first pilot oil port b. The first pilot oil port a is connected to the second switch valve group 52, and the first pilot oil port b is connected to the first switch valve group 51 through the overflow valve group 6.

[0073] That is to say, when only the proportional valve group 4 is working, the first isolation valve 14 is in the disconnected state. When only any one of the switch valve groups 5 is working, the hydraulic oil of the working switch valve group 5 is fed back to the first pilot oil port connected thereto. Under the action of the hydraulic oil pressure of the first pilot oil port, the first isolation valve 14 is turned on, so that the hydraulic oil flowing out of the high pressure signal Px port of the relief valve group 6 flows through the first isolation valve 14 and is divided into two paths, one of which flows to the load sensitive port X of the second variable pump 3, and the other flows through the Ls on-off control valve 7 and flows through the load sensitive port X of the first variable pump 2. When the proportional valve group 4 and the switch valve group 5 are working in combination, since the Ls on-off control valve 7 is disconnected, the hydraulic oil of the working switch valve group 5 is fed back to the first pilot oil port connected thereto. Under the action of the hydraulic oil pressure of the first pilot oil port, the first isolation valve 14 is turned on, so that the hydraulic oil flowing out of the high pressure signal Px port of the relief valve group 6 flows through the first isolation valve 14 and flows to the load sensitive port X of the second variable pump 3. That is to say, when only the second actuator 22 controlled by the switch valve group 5 is in motion, the working signal of the switch valve group 5 can be fed back to the first variable pump 2 and the second variable pump 3 through the first isolation valve 14. When the second actuator 22 controlled by the switch valve group 5 and the first actuator 21 controlled by the proportional valve group 4 are in combined motion, the working signal of the switch valve group 5 can be fed back to the second variable pump 3 through the first isolation valve 14.

[0074] Further, please continue to combine Figure 1 and Figure 3In some embodiments, the proportional valve and switch valve mixed control hydraulic system further includes a second isolation valve 15, the working oil port of the second isolation valve 15 is respectively connected to the pressure port of the first isolation valve 14 and the high pressure signal Px port of the overflow valve group 6, the second isolation valve 15 includes at least one second pilot oil port, the number of the second pilot oil ports is the same as the number of the proportional valve groups 4, and the second pilot oil port is connected to the load sensitive Ls port of the proportional valve group 4 in a one-to-one correspondence, when any one of the proportional valve groups 4 is working, the pressure port of the second isolation valve 15 is connected to its working oil port; when only the switch valve group 5 is working, the pressure port of the second isolation valve 15 is disconnected from its working oil port. For example, when the number of the proportional valve group 4 is one, the second isolation valve 15 includes a second pilot oil port a, and the second pilot oil port a is connected to the load sensitive Ls port of the proportional valve group 4. When the second isolation valve 15 includes two second pilot oil ports, that is, the second isolation valve 15 includes the second pilot oil port a and the second pilot oil port b, since there is only one proportional valve group, the second pilot oil port b can be connected to the return oil port.

[0075] That is to say, when only the switch valve group 5 is working, the second isolation valve 15 is in the disconnected state. When the proportional valve group 4 is working, the oil pressure of the load sensitive Ls port of the proportional valve group 4 acts on the second pilot oil port connected thereto, so that under the action of the oil pressure of the second pilot oil port, the second isolation valve 15 is turned on. When only the first actuator 21 controlled by the proportional valve group 4 is working, the second isolation valve 15 is turned on, so that the first variable pump 2 and the second variable pump 3 can build up pressure normally.

[0076] For further information, please refer to Figure 1 In some embodiments, the proportional valve and switch valve mixed control hydraulic system further includes a first check valve 16, which is arranged between the working oil port of the first isolation valve 14 and the load sensing port X of the second variable pump 3. It can be understood that the oil inlet of the first check valve 16 is connected to the working oil port of the first isolation valve 14, and the oil outlet of the first check valve 16 is connected to the load sensing port X of the second variable pump 3. In this embodiment, the first check valve 16 is arranged to prevent the oil in the load sensing port X of the second variable pump 3 from flowing back to the working oil port of the first isolation valve 14 due to the disconnection of the first isolation valve 14 when only the first actuator 21 controlled by the proportional valve group 4 is working, and returning the oil to the oil tank through the return oil port of the first isolation valve 14, and failing to build up pressure at the load feedback port Ls of the proportional valve group 4. That is, the existence of the first check valve 16 can realize that when only the first actuator 21 controlled by the proportional valve group 4 is in motion, the load feedback port Ls of the proportional valve group 4 can build up pressure normally.

[0077] In addition, please continue to refer to Figure 1In some embodiments, the proportional valve and switch valve mixed control hydraulic system further includes a second one-way valve 17 and a third one-way valve 18. The second one-way valve 17 is arranged between the first variable pump 2 and the first pressure oil port of the single-double pump switching control valve group 1; the third one-way valve 18 is arranged between the second variable pump 3 and the second pressure oil port of the single-double pump switching control valve group 1. It can be understood that the oil inlet of the second one-way valve 17 is connected to the first variable pump 2, and the oil outlet is connected to the first pressure oil port; the oil inlet of the third one-way valve 18 is connected to the second variable pump 3, and the oil outlet is connected to the second pressure oil port. That is, this embodiment prevents the hydraulic oil of the single-double pump switching control valve group 1 from flowing back to the first variable pump 2 and / or the second variable pump 3 by arranging the second one-way valve 17 and the third one-way valve 18.

[0078] It should be noted that the present embodiment does not limit the specific types of the first variable pump 2 and the second variable pump 3. For example, in some embodiments, the first variable pump 2 and the second variable pump 3 can be load-sensitive variable pumps. In addition, the embodiment of the present invention does not limit the number of the first variable pump 2 and the second variable pump 3. The first variable pump 2 and the second variable pump 3 can be one or at least two. In addition, the first variable pump 2 and the second variable pump 3 can be arranged in series and driven by one prime mover; the first variable pump 2 and the second variable pump 3 can also be arranged separately and driven by different prime movers.

[0079] In addition, the embodiments of the present invention do not limit the number of proportional valve groups 4 and switch valve groups 5. The number of proportional valve groups 4 and switch valve groups 5 can be one or at least two respectively. The oil circuit connection principle of multiple proportional valve groups 4 is the same, and the oil circuit connection principle of multiple switch valve groups 5 is the same.

[0080] In addition, the embodiment of the present invention does not limit the specific structure of the proportional valve group 4. In some embodiments, the proportional valve group 4 is a load-sensitive proportional valve group 4. In addition, the pilot signal of the load-sensitive proportional valve group 4 can be a hydraulic pilot or an electric pilot.

[0081] In addition to the above-mentioned proportional valve and switch valve mixed control hydraulic system, the present invention also provides an engineering machinery including the proportional valve and switch valve mixed control hydraulic system disclosed in the above-mentioned embodiment. For the structures of other parts of the engineering machinery, please refer to the prior art and will not be repeated in this article.

[0082] The focus of this embodiment is to use the proportional valve and switch valve mixed control hydraulic system disclosed in any of the above embodiments, which has the same beneficial effects as the above proportional valve and switch valve mixed control hydraulic system, and will not be repeated here.

[0083] It should also be noted that, in this specification, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0084] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0085] The above is a detailed introduction to the proportional valve and switch valve hybrid control hydraulic system and engineering machinery provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A proportional valve and switch valve mixed control hydraulic system, characterized in that: include: A single-double pump switching control valve group (1) comprises a first pressure oil port, a second pressure oil port, a first working oil port, a second working oil port, a third working oil port and a fourth working oil port, and can be switched between a first position state and a second position state. When the single-double pump switching control valve group (1) is in the first position state, the first pressure oil port is communicated with the first working oil port and the second working oil port respectively, and the second pressure oil port is communicated with the third working oil port and the fourth working oil port respectively; when the single-double pump switching control valve group (1) is in the second position state, the first pressure oil port is communicated with the first working oil port, and the second pressure oil port is communicated with the third working oil port; A first variable displacement pump (2), connected to the first pressure oil port; A second variable displacement pump (3), connected to the second pressure oil port; A proportional valve group (4) is used to control the first actuator (21) to perform stepless speed regulation, comprising a first oil inlet and a second oil inlet, wherein the first oil inlet is connected to the first working oil port, and the second oil inlet is connected to the fourth working oil port; A switch valve group (5) is used to control the second actuator (22) to work at a constant speed, comprising a third oil inlet, wherein the third oil inlet is connected to the second working oil port and the third working oil port respectively; The Ls on-off control valve (7) is respectively connected to the load sensitive Ls port of the proportional valve group (4), the pressure oil port of the second variable pump (3), the control oil port of the first variable pump (2) and the control oil port of the second variable pump (3). When the single-double pump switching control valve group (1) is in the first position state, the Ls on-off control valve (7) is in the on state, so that the load feedback oil circuits of the first variable pump (2) and the second variable pump (3) are connected; when the single-double pump switching control valve group (1) is in the second position state, the Ls on-off control valve (7) is in the off state, so that the load feedback oil circuits of the first variable pump (2) and the second variable pump (3) are disconnected.

2. The proportional valve and switch valve mixed control hydraulic system according to claim 1 is characterized in that: Also includes: A first pressure sensor (8) for detecting the oil circuit pressure for controlling the action of the first actuator (21); a second pressure sensor (9) for detecting the oil circuit pressure for controlling the action of the second actuator (22); The solenoid valve (10) is connected between the single-double pump switching control valve group (1) and the pilot oil circuit. When the single-double pump switching control valve group (1) is in the first position state, the solenoid valve (10) is disconnected; when the first pressure sensor (8) and the second pressure sensor (9) detect pressure signals at the same time, the solenoid valve (10) is connected, so that under the action of the pilot oil circuit, the single-double pump switching control valve group (1) is switched from the first position state to the second position state.

3. The proportional valve and switch valve mixed control hydraulic system according to claim 2 is characterized in that: Also includes: At least two pilot handles (11) connected to the pilot oil circuit and used to control the actions of the first actuator (21) and the second actuator (22) respectively; A shuttle valve group (12) is connected to the control oil circuit of each pilot handle (11) and is used to output the pressure of the corresponding control oil circuit when the pilot handle (11) is opened; The first pressure sensor (8) and the second pressure sensor (9) are respectively connected to the outlet of the shuttle valve group (12).

4. The proportional valve and switch valve hybrid control hydraulic system according to claim 2, characterized in that: The pilot control port of the Ls on-off control valve (7) is connected to the working oil port of the solenoid valve (10) so as to control the position switching of the Ls on-off control valve (7) by the on-off power of the solenoid valve (10).

5. The proportional valve and switch valve mixed control hydraulic system according to any one of claims 1 to 4, characterized in that: Also includes: A relief valve group (6) is provided between the single-pump and double-pump switching control valve group (1) and the switch valve group (5), and is used to set the maximum pressure of the switch valve group (5) when it is in operation; The third oil inlet is connected to the second working oil port and the third working oil port respectively through the overflow valve group (6); The Ls on-off control valve (7) is connected to the pressure oil port of the second variable pump (3) via the high-pressure signal Px port of the overflow valve group (6).

6. The proportional valve and switch valve hybrid control hydraulic system according to claim 5, characterized in that: Also includes: The hydraulically controlled stop valve (13) is used to set different system pressures for the overflow valve group (6) when the number of the switch valve groups (5) is at least two and the second actuators (22) corresponding to different switch valve groups (5) are actuated.

7. The proportional valve and switch valve hybrid control hydraulic system according to claim 5, characterized in that: Also includes: a first isolation valve (14), whose pressure port is connected to the high-pressure signal Px port, a working oil port of the first isolation valve (14) is connected to the load sensing port X of the second variable pump (3), and is connected to the load sensing port X of the first variable pump (2) through the Ls on-off control valve (7); The first isolation valve (14) comprises at least one first pilot oil port, the number of the first pilot oil ports being the same as the number of the switch valve groups (5), and the first pilot oil ports being connected to the switch valve groups (5) in a one-to-one correspondence; when any one of the switch valve groups (5) is working, the pressure port of the first isolation valve (14) is connected to its working oil port; when only the proportional valve group (4) is working, the pressure port of the first isolation valve (14) is disconnected from its working oil port.

8. The proportional valve and switch valve hybrid control hydraulic system according to claim 7, characterized in that: Also includes: The second isolation valve (15) has a working oil port which is respectively connected to the pressure port of the first isolation valve (14) and the high-pressure signal port Px, and includes at least one second pilot oil port. The number of the second pilot oil ports is the same as the number of the proportional valve groups (4), and the second pilot oil ports are connected to the load sensitive Ls ports of the proportional valve groups (4) in a one-to-one correspondence. When any one of the proportional valve groups (4) is working, the pressure port of the second isolation valve (15) is connected to its working oil port; when only the switch valve group (5) is working, the pressure port of the second isolation valve (15) is disconnected from its working oil port.

9. The proportional valve and switch valve hybrid control hydraulic system according to claim 8, characterized in that: Also includes: The first one-way valve (16) is provided between the working oil port of the first isolation valve (14) and the load sensing port X of the second variable pump (3).

10. The proportional valve and switch valve mixed control hydraulic system according to any one of claims 1 to 4, characterized in that: Also includes: a second one-way valve (17) disposed between the first variable pump (2) and the first pressure oil port; A third one-way valve (18) is provided between the second variable pump (3) and the second pressure oil port.

11. An engineering machine, characterized in that: A hybrid control hydraulic system comprising the proportional valve and switch valve as described in any one of claims 1 to 10.

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