Quick-change electromagnetic valve group and hydraulic system

Abstract

The application relates to the technical field of hydraulic systems of excavators, in particular to a quick-change electromagnetic valve group and a hydraulic system, which comprises a valve block and an electromagnetic valve. The valve block is provided with an internal flow channel. The electromagnetic valve is a two-position four-way electromagnetic valve. The valve block is provided with a first working oil port and a second working oil port. An oil inlet port is used for being connected with a variable hydraulic pump. The second working oil port is used for being connected with a rodless chamber of a quick-change oil cylinder. The second working oil port is used for being connected with a rod chamber of the quick-change oil cylinder. The valve block further comprises a load feedback oil port, which is connected with the second working oil port and is connected with the variable hydraulic pump, so as to feed the oil pressure in the rod chamber to the variable hydraulic pump, and make the oil pressure output by the variable hydraulic pump greater than the oil pressure in the rod chamber. In the application, the operator does not need to additionally operate the large arm or the small arm of the excavator or other additional actions, and directly drives the quick-change oil cylinder to contract, so that the tool replacement is quickly and safely completed.

Description

Technical Field

[0001] This application relates to the field of hydraulic systems for excavators, and in particular to a quick-change solenoid valve assembly and hydraulic system. Background Technology

[0002] In actual construction, in addition to regular excavation operations, excavators also need to perform crushing, grabbing and other operations. Therefore, excavators need to be equipped with different attachments (such as buckets, breakers, grabs, etc.) according to different operational requirements.

[0003] Excavators operate in various modes, such as digging, breaking, hydraulic shearing, and grabbing. These operations all utilize different working attachments, which are frequently changed depending on the working conditions. Manual assembly and disassembly not only increases labor intensity but is also time-consuming, labor-intensive, and extremely inefficient. Therefore, most construction machinery, including excavators, is equipped with quick-change attachment systems.

[0004] The attachment quick-change device mainly includes a mechanical connection mechanism and a hydraulic control mechanism. The hydraulic control mechanism is connected to the hydraulic power system of the excavator host, thereby using the hydraulic oil of the excavator host as power to drive the mechanical connection mechanism to lock or unlock the attachment.

[0005] In the prior art, the hydraulic control mechanism of the attachment quick-change device includes a quick-change cylinder (1) and a quick-change control valve. The inlet (P port) and return (T port) of the quick-change control valve are connected to the hydraulic power system of the excavator host. The first working port (A port) and the second working port (B port) of the quick-change control valve are connected to the two chambers of the quick-change cylinder. The quick-change control valve connects the inlet (P port) with the first working port (A port) or the inlet (P port) with the second working port (B port) to make the piston of the quick-change cylinder extend or retract, thereby realizing the quick-change cylinder driving the mechanical connection structure to lock or unlock the attachment.

[0006] When the quick-change solenoid valve is in the reversing state, the excavator's main unit's variable displacement hydraulic pump is unloaded. When the quick-change control valve is de-energized, the variable displacement hydraulic pump cannot promptly input hydraulic oil into the quick-change cylinder. The conventional approach is to operate the excavator's boom and arm to maintain the variable displacement hydraulic pump's output, thus inputting hydraulic oil into the quick-change cylinder. This method is cumbersome, slows down the quick-change cylinder's response time, reduces attachment change efficiency, and poses certain safety hazards. Summary of the Invention

[0007] To enable safe and quick replacement of excavator attachments, this application provides a quick-change solenoid valve assembly and hydraulic system.

[0008] This application provides a quick-change solenoid valve assembly and hydraulic system, which adopts the following technical solution:

[0009] A quick-change solenoid valve assembly includes a valve block and a solenoid valve. The valve block has an internal flow channel. The solenoid valve is a two-position four-way solenoid valve. The valve block has an oil inlet, an oil return port, a first working port, and a second working port connected to the solenoid valve. The oil inlet is used to connect to an external variable hydraulic pump. The second working port is used to connect to the rodless chamber of the quick-change cylinder and the rod chamber of the quick-change cylinder. The solenoid valve controls the connection between the oil inlet and the first or second working port to drive the quick-change cylinder to extend or retract. The valve block also includes a load feedback port connected to the second working port. The load feedback port is connected to the external variable hydraulic pump to feed back the oil pressure in the rod chamber to the variable hydraulic pump, so that the oil pressure output by the variable hydraulic pump is greater than the oil pressure in the rod chamber.

[0010] By adopting the above technical solution, and by setting a load feedback port on the valve block, when the solenoid valve reverses, the oil pressure in the rod chamber can be fed back to the variable hydraulic pump; thus, the oil pressure output by the variable hydraulic pump is greater than the oil pressure in the rod chamber, thereby continuously supplying hydraulic oil to the rod chamber of the quick-change cylinder, causing the piston of the quick-change cylinder to continuously contract.

[0011] This means that the operator does not need to perform any additional operations on the excavator's boom or arm. When the excavator is in standby or low-load condition, the quick-change cylinder can be directly driven to retract, thus completing the attachment change quickly and safely.

[0012] Optionally, it also includes a first check valve, which is disposed on the internal flow channel connecting the second working port and the load feedback port; the first check valve allows hydraulic oil to flow unidirectionally from the second working port to the load feedback port.

[0013] By adopting the above technical solution, and by setting a first check valve in the internal flow channel of the valve block, the high-pressure hydraulic oil in the variable pressure hydraulic pump is prevented from affecting the action of the quick-change cylinder under other working conditions of the excavator; thereby improving the response speed and control accuracy of attachment changes and improving the stability of excavator attachment changes.

[0014] Optionally, a pressure reducing valve is also included, which is disposed in the internal flow channel between the solenoid valve and the oil inlet of the valve block, through which hydraulic oil flows to the solenoid valve.

[0015] By adopting the above technical solution, the oil pressure output by the variable hydraulic pump is usually consistent with the oil pressure output by the excavator host, that is, the variable hydraulic pump will output a higher oil pressure, and the output flow rate of the variable hydraulic pump will change with the load. In contrast, the quick-change cylinder is a small actuator, and a smaller oil pressure is sufficient to complete the extension and retraction action; furthermore, the solenoid valve cannot withstand high oil pressure for extended periods.

[0016] By installing a pressure reducing valve inside the valve block, the hydraulic oil can flow steadily into the quick-change cylinder through the solenoid valve due to the constant outlet pressure of the pressure reducing valve; this allows the quick-change cylinder to extend and retract smoothly, making it easier for operators to operate and improving the convenience of attachment changes.

[0017] Optionally, it also includes a hydraulically controlled check valve, which is disposed in the internal flow channel of the first working port of the solenoid valve and the valve block. The hydraulically controlled port of the hydraulically controlled check valve is connected to the second working port. The hydraulically controlled check valve allows hydraulic oil to flow unidirectionally to the first working port. When the oil pressure of the external rod chamber is transmitted to the hydraulically controlled port of the hydraulically controlled check valve, the hydraulic oil flows through the first working port of the valve block, the hydraulically controlled check valve, and the solenoid valve.

[0018] Optionally, a three-way hydraulic control valve is also included, which is disposed on the valve block. The three-way hydraulic control valve includes a first valve body, a first valve core, a first spring, and a first limiting block. The first valve core divides the valve cavity of the first valve body into a first valve cavity and a second valve cavity. The first valve cavity is connected to a first working oil port of the valve block, and the second valve cavity is connected to a second working oil port of the valve block. The first valve body is provided with a first output port. The first spring is disposed in the first valve cavity, and the first limiting block is fixed in the second valve cavity. The first spring forces the first valve core to abut against the first limiting block, thereby blocking the first output port. The three-way hydraulic control valve is used to divert high-pressure oil from the second working oil port to the first working oil port.

[0019] Optionally, the valve block has a first control flow channel, one end of which is connected to the first output port, and the other end of which is connected to the first working oil port.

[0020] Optionally, it also includes a hydraulically controlled on / off valve, which is disposed in the valve block; the valve block has a second control flow channel inside, one end of the second control flow channel is connected to the first working oil port, and the other end of the control flow channel is connected to the second working oil port; the hydraulic control port of the hydraulically controlled on / off valve is connected to the first output port of the three-way hydraulically controlled valve; high-pressure oil enters the hydraulic control port of the hydraulically controlled on / off valve through the first output port, so that the hydraulically controlled on / off valve opens the second control flow channel.

[0021] Optionally, the hydraulic control on / off valve includes a second valve body, a second valve core, and a second spring; the second valve core divides the valve chamber of the second valve body into a third valve chamber and a fourth valve chamber, the hydraulic control port of the hydraulic control on / off valve is connected to the third valve chamber, and the second valve body is provided with a first communication port connected to the second control flow channel; the second spring is disposed in the fourth valve chamber, and the second spring forces the second valve core to block the first communication port of the second valve body; the second valve core is provided with a second communication port, and high-pressure oil flows into the third valve chamber of the hydraulic control on / off valve through the three-way hydraulic control valve, and the high-pressure oil drives the second valve core to compress the second spring, so that the second communication port of the second valve core is connected to the first communication port of the second valve body.

[0022] It also includes a second limiting block, which is fixed in the third valve chamber, and the second spring forces the second valve core to abut against the second limiting block.

[0023] A hydraulic system includes the aforementioned quick-change solenoid valve assembly, and further includes a quick-change cylinder and a variable hydraulic pump, wherein the variable hydraulic pump is connected to the quick-change cylinder via the quick-change solenoid valve assembly.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. By setting a load feedback port on the valve block, when the solenoid valve reverses, the oil pressure in the rod chamber can be fed back to the variable hydraulic pump. This makes the oil pressure output by the variable hydraulic pump greater than the oil pressure in the rod chamber, thus continuously supplying hydraulic oil to the rod chamber of the quick-change cylinder. This causes the piston of the quick-change cylinder to continuously contract. The operator does not need to perform any additional operations such as operating the boom or arm of the excavator. When the excavator is in standby or low load state, the quick-change cylinder can be directly driven to contract, thus completing the attachment change quickly and safely.

[0026] 2. By setting a first check valve in the internal flow channel of the valve block, the high-pressure hydraulic oil in the variable pressure hydraulic pump is prevented from affecting the action of the quick-change cylinder under other working conditions of the excavator; thereby improving the response speed and control accuracy of attachment changes and improving the stability of excavator attachment changes;

[0027] 3. By setting a three-way hydraulic control valve between the third and fourth connecting channels, when the attachment is suspended, the piston of the quick-change cylinder cannot retract effectively, and the attachment remains locked, thereby achieving the purpose of "suspended anti-unlocking" and further improving the safety of attachment replacement. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the quick-change solenoid valve assembly in Example 1.

[0029] Figure 2This is a schematic diagram of the first state of the hydraulic system in Example 1.

[0030] Figure 3 This is a schematic diagram of the structure of the quick-change solenoid valve assembly in the first state in Example 1.

[0031] Figure 4 This is a schematic diagram of the second state of the hydraulic system in Example 1.

[0032] Figure 5 This is a schematic diagram of the second state of the quick-change solenoid valve assembly in Example 1.

[0033] Figure 6 This is a schematic diagram of the first state of the hydraulic system in Example 2.

[0034] Figure 7 This is a schematic diagram of the first state of the quick-change solenoid valve assembly in Example 2.

[0035] Figure 8 This is a schematic diagram of the second state of the hydraulic system in Example 2.

[0036] Figure 9 This is a schematic diagram of the second state of the quick-change solenoid valve assembly in Example 2.

[0037] Figure 10 This is a schematic diagram of the hydraulic system structure in Example 3.

[0038] Figure 11 This is a schematic diagram of the first state of the quick-change solenoid valve assembly in Example 3.

[0039] Figure 12 This is a schematic diagram of the second state of the quick-change solenoid valve assembly in Example 3.

[0040] Explanation of reference numerals in the attached diagram: 1. Quick-change cylinder; 11. Rodless chamber; 12. Rod chamber; 13. Piston; 2. Variable displacement hydraulic pump; 21. Second check valve; 3. Valve block; 31. Oil inlet; 32. Oil return port; 33. First working port; 34. Second working port; 35. Load feedback port; 36. First connecting channel; 37. Second connecting channel; 38. Third connecting channel; 39. Fourth connecting channel; 301. First control channel; 302. Second control channel; 4. Solenoid valve; 5. First check valve; 6. Pressure reducing valve; 7. Hydraulic check valve; 8. Three-way hydraulic valve; 81. First valve body; 811. First valve chamber; 812. Second valve chamber; 813. First output port; 82. First valve core; 83. First spring; 84. First limit block; 9. Hydraulic on / off valve; 91. Second valve body; 911. First connecting port; 912. Third valve chamber; 913. Fourth valve chamber; 92. Second valve core; 921. Second connecting port; 93. Second spring; 94. Second limit block. Detailed Implementation

[0041] The following is in conjunction with the appendix Figure 1 -12 provides further details regarding this application.

[0042] Example 1: This application discloses a quick-change solenoid valve assembly and hydraulic system.

[0043] Reference Figure 1 and Figure 2 The hydraulic system includes a quick-change solenoid valve assembly, a quick-change cylinder 1, and a variable hydraulic pump 2. The variable hydraulic pump 2 is connected to the quick-change cylinder 1 via the quick-change solenoid valve assembly. The hydraulic system of this application is used in the attachment quick-change device of an excavator. The attachment quick-change device mainly includes a mechanical connection mechanism and the hydraulic system of this application. The hydraulic system of this application drives the mechanical connection mechanism to lock or unlock with the attachment.

[0044] Reference Figure 2 The quick-change cylinder 1 is used to drive the mechanical connection mechanism of the quick-change attachment to lock or unlock with the attachment. When the piston 13 of the quick-change cylinder 1 extends outward, the quick-change cylinder 1 drives the mechanical connection mechanism to lock with the attachment; when the piston 13 of the quick-change cylinder 1 retracts inward, the quick-change cylinder 1 drives the mechanical connection mechanism to unlock and separate from the attachment.

[0045] Reference Figure 2 The piston 13 of the quick-change cylinder 1 divides its internal chamber into a rodless chamber 11 and a rod chamber 12. By controlling the flow of hydraulic oil into the rodless chamber 11 or the rod chamber 12, the piston 13 in the quick-change cylinder 1 is driven to extend outward or retract inward. The variable hydraulic pump 2 can be installed independently or can be a variable hydraulic pump 2 from the excavator's main unit. The variable hydraulic pump 2 draws hydraulic oil from the tank, and the hydraulic oil is delivered to the quick-change cylinder 1 via the quick-change solenoid valve assembly to drive the piston 13 in the quick-change cylinder 1 to extend and retract. In this embodiment, a second check valve 21 is provided between the variable hydraulic pump 2 and the quick-change solenoid valve assembly, allowing hydraulic oil to flow unidirectionally from the variable pump to the quick-change solenoid valve assembly.

[0046] Reference Figure 3 The quick-change solenoid valve assembly includes a valve block 3, a solenoid valve 4, a first check valve 5, a pressure reducing valve 6, and a hydraulically controlled check valve 7.

[0047] Reference Figure 3The valve block 3 has an internal flow channel. The solenoid valve 4 is a two-position four-way solenoid valve with a P port, a T port, an A port, and a B port. Correspondingly, the valve block 3 has an oil inlet 31 (P port), an oil return port 32 (T port), a first working oil port 33 (A port), and a second working oil port 34 (B port) connected to the solenoid valve 4. That is, the valve block 3 has a first connecting flow channel 36, a second connecting flow channel 37, a third connecting flow channel 38, and a fourth connecting flow channel 39. The first connecting flow channel 36 is used to connect the P port of the solenoid valve 4 with the oil inlet 31 (P port) of the valve block 3; the second connecting flow channel 37 is used to connect the T port of the solenoid valve 4 with the oil return port 32 (T port) of the valve block 3; the third connecting flow channel 38 is used to connect the A port of the solenoid valve 4 with the first working oil port 33 (A port) of the valve block 3; and the fourth connecting flow channel 39 is used to connect the B port of the solenoid valve 4 with the second working oil port 34 (B port) of the valve block 3.

[0048] Reference Figure 2 and Figure 3 The oil inlet 31 is used to connect to the external variable hydraulic pump 2, the first working oil port 33 is used to connect to the rodless chamber 11 of the quick-change cylinder 1, and the second working oil port 34 is used to connect to the rod chamber 12 of the quick-change cylinder 1. The solenoid valve 4 controls the oil inlet 31 to connect to the first working oil port 33 or the second working oil port 34 to drive the quick-change cylinder 1 to extend and retract.

[0049] Referring to Figure 3, the pressure reducing valve 6 is located in the internal flow channel between the solenoid valve 4 and the oil inlet 31 of the valve block 3. Hydraulic oil flows to the solenoid valve 4 through the pressure reducing valve 6. The oil pressure output by the variable hydraulic pump 2 is usually consistent with the oil pressure output by the excavator host, that is, the variable hydraulic pump 2 will output hydraulic oil with a higher oil pressure, and the output flow rate of the variable hydraulic pump 2 will change with the load. The quick-change cylinder 1 is a small actuator, and a small oil pressure is sufficient to complete the extension and retraction action; and the solenoid valve 4 cannot withstand a large oil pressure for a long time. By setting the pressure reducing valve 6 in the valve block 3, the hydraulic oil can flow steadily into the quick-change cylinder 1 through the solenoid valve 4 because the outlet pressure of the pressure reducing valve 6 is constant; thus, the quick-change cylinder 1 extends and retracts smoothly, which is convenient for operators and improves the ease of attachment changes.

[0050] Reference Figure 4 and Figure 5 The hydraulic control check valve 7 is located in the internal flow channel between the solenoid valve 4 and the first working port 33 of the valve block 3. The hydraulic control port of the hydraulic control check valve 7 is connected to the second working port 34. The hydraulic control check valve 7 allows the hydraulic oil to flow unidirectionally to the first working port 33. When the oil pressure of the external rod chamber 12 is transmitted to the hydraulic control port of the hydraulic control check valve 7, the hydraulic oil flows through the first working port 33 of the valve block 3, the hydraulic control check valve 7 and the solenoid valve assembly.

[0051] Reference Figure 4 and Figure 5The valve block 3 also includes a load feedback port 35, which is connected to the second working port 34. The load feedback port 35 is externally connected to a variable hydraulic pump 2 to feed back the oil pressure in the rod chamber 12 to the variable hydraulic pump 2, so that the oil pressure output by the variable hydraulic pump 2 is greater than the oil pressure in the rod chamber 12. A first check valve 5 is disposed on the internal flow channel connecting the second working port 34 and the load feedback port 35; the first check valve 5 allows hydraulic oil to flow unidirectionally from the second working port 34 to the load feedback port 35.

[0052] Reference Figure 2 and Figure 3 When the excavator is working normally, the oil inlet 31 of valve block 3 is connected to the first working oil port 33, and the second working oil port 34 of valve block 3 is connected to the return oil port 32. At this time, the hydraulic control check valve 7 controls the hydraulic oil to flow unidirectionally from the solenoid valve group to the rod chamber 12 of the quick-change cylinder 1.

[0053] Reference Figure 4 and Figure 5 When the solenoid valve 4 reverses to unlock the attachment, the oil inlet 31 of the valve block 3 is connected to the second working oil port 34, and the second working oil port 34 of the valve block 3 is connected to the return oil port 32. Hydraulic oil flows along the path of the variable hydraulic pump 2, the oil inlet 31 of the valve block 3, the pressure reducing valve 6, the solenoid valve 4, and the second working oil port 34 of the valve block 3, flowing into the rod chamber 12 of the quick-change cylinder 1. The higher-pressure hydraulic oil in the rod chamber 12 and the fourth connecting flow channel 39 acts on the hydraulic control port of the hydraulic control check valve 7, changing the flow direction of the hydraulic oil in the hydraulic control check valve 7; causing the hydraulic oil in the rodless chamber 11 to flow along the path of the first working oil port 33 of the valve block 3, the hydraulic control check valve 7, the solenoid valve 4, and the return oil port 32 of the valve block 3, allowing the hydraulic oil in the rodless chamber 11 to flow back into the oil tank.

[0054] Reference Figure 2 and Figure 3 When the attachment is replaced, the solenoid valve 4 reverses, connecting the oil inlet 31 of the valve block 3 to the first working oil port 33, and the second working oil port 34 of the valve block 3 to the return oil port 32. Hydraulic oil flows along the path of the variable hydraulic pump 2, the oil inlet 31 of the valve block 3, the pressure reducing valve 6, the solenoid valve 4, and the first working oil port 33 of the valve block 3. Higher pressure hydraulic oil flows into the rodless chamber 11 of the quick-change cylinder 1, pushing the piston 13 of the quick-change cylinder 1 outward, thus locking the attachment quick-change device with the attachment. Meanwhile, the hydraulic oil in the rod chamber 12 flows along the path of the second working oil port 34 of the valve block 3, the solenoid valve 4, and the return oil port 32 of the valve block 3, causing the hydraulic oil in the rod chamber 12 to flow back into the oil tank.

[0055] The implementation principle of a hydraulic system according to an embodiment of this application is as follows:

[0056] Reference Figure 4 and Figure 5 By setting a load feedback port 35 on the valve block 3, when the solenoid valve 4 reverses, when the variable hydraulic pump 2 delivers high-pressure hydraulic oil to the rod chamber 12 of the quick-change cylinder 1, the hydraulic oil in the fourth connecting channel 39, in addition to flowing to the rod chamber 12 of the quick-change cylinder 1, will also be diverted to the load feedback port 35. The load feedback port 35 is connected to the variable hydraulic pump 2 of the excavator host, thereby feeding back the oil pressure in the rod chamber 12 to the variable hydraulic pump 2; thus, the oil pressure output by the variable hydraulic pump 2 is greater than the oil pressure in the rod chamber 12, thereby continuously delivering hydraulic oil to the rod chamber 12 of the quick-change cylinder 1, causing the piston 13 of the quick-change cylinder 1 to continuously contract.

[0057] By setting a first check valve 5 in the internal flow channel of valve block 3, the high-pressure hydraulic oil in the variable pressure hydraulic pump is prevented from affecting the action of quick-change cylinder 1 under other working conditions of the excavator; thereby improving the response speed and control accuracy of attachment changes and improving the stability of excavator attachment changes.

[0058] Reference Figure 4 and Figure 5 This means that the operator does not need to perform any additional operations on the excavator's boom or arm. When the excavator is in standby or low load state, the quick-change cylinder 1 can be directly driven to retract, thereby completing the attachment change quickly and safely.

[0059] Example 2: This application discloses a quick-change solenoid valve assembly and hydraulic system.

[0060] The difference between Example 2 and Example 1 is as follows:

[0061] When the attachment is suspended in the air and not placed on the ground, if the operator accidentally operates solenoid valve 4 to switch directions, the attachment may unlock at a height, thus affecting the safety of excavator operation. This embodiment further improves the quick-change solenoid valve assembly to further enhance the safety of attachment replacement.

[0062] Reference Figure 6 and Figure 7 The quick-change solenoid valve assembly also includes a three-way hydraulic control valve 8, which is mounted on the valve block 3. The three-way hydraulic control valve 8 includes a first valve body 81, a first valve core 82, a first spring 83, and a first limiting block 84. The first valve core 82 divides the valve chamber of the first valve body 81 into a first valve chamber 811 and a second valve chamber 812. The first valve chamber 811 is connected to the first working oil port 33 of the valve block 3, and the second valve chamber 812 is connected to the second working oil port 34 of the valve block 3. That is, the first valve chamber 811 of the three-way hydraulic control valve 8 is connected to the third connecting flow channel 38, and the second valve chamber 812 of the three-way hydraulic control valve 8 is connected to the fourth connecting flow channel 39.

[0063] Reference Figure 7The first valve body 81 is provided with a first output port 813, the first spring 83 is disposed in the first valve cavity 811, and the first limiting block 84 is fixed in the second valve cavity 812. The first spring 83 forces the first valve core 82 to abut against the first limiting block 84, so that the first valve core 82 blocks the first output port 813; the three-way hydraulic control valve 8 is used to divert the high pressure oil at the second working oil port 34 to the first working oil port 33.

[0064] Reference Figure 7 In this embodiment, the valve block 3 has a first control flow channel 301. One end of the first control flow channel 301 is connected to the first output port 813, and the other end of the first control flow channel 301 is connected to the first working oil port 33. That is, one end of the first control flow channel 301 is connected to the fourth connecting flow channel 39, and the other end of the first control flow channel 301 is connected to the third connecting flow channel 38.

[0065] The implementation principle of a hydraulic system according to an embodiment of this application is as follows:

[0066] Reference Figure 6 and Figure 7 When the excavator is working normally, the variable hydraulic pump 2 delivers high-pressure oil to the rodless chamber 11 of the quick-change cylinder 1. At this time, the hydraulic oil in the first valve chamber 811 of the three-way hydraulic control valve 8 is high-pressure oil, while the hydraulic oil in the second valve chamber 812 is low-pressure oil. As a result, under the action of the oil pressure difference between the first spring 83 and the hydraulic oil on both sides of the first valve core 82, the first valve core 82 abuts against the first limit block 84, and the first valve core 82 blocks the first output port 813 on the first tower body; thus, the hydraulic oil cannot flow in the first control flow channel 301.

[0067] Reference Figure 8 and 9 If the attachment is suspended, its weight will act on the quick-change cylinder 1. To unlock the attachment, when the piston in the quick-change cylinder 1 retracts, it is necessary to overcome the force of the suspended attachment on the piston, which means that the hydraulic oil pressure required in the rod chamber 12 is greater. The variable hydraulic pump 2 needs to pump hydraulic oil with greater pressure into the rod chamber 12.

[0068] Compared to when the attachment is placed on the ground, when the attachment is suspended in the air, if the operator operates the solenoid valve 4 to switch directions, the variable hydraulic pump 2 will deliver high-pressure oil to the rod chamber 12 of the quick-change cylinder 1 in an attempt to compress the piston rod 13 into the quick-change cylinder 1. This will result in a larger oil pressure in the rod chamber 12 and a smaller oil pressure in the rodless chamber 11. At this time, the oil pressure in the rod chamber 12 is much greater than the oil pressure in the rodless chamber 11; that is, the oil pressure in the fourth connecting channel 39 will be greater than the oil pressure in the third connecting channel 38, and the oil pressure in the second valve chamber 812 will be greater than the oil pressure in the first valve chamber 811.

[0069] Reference Figure 8 and 9 When the operator accidentally switches the solenoid valve 4 to the unlock position, the hydraulic oil attempts to enter the rod chamber 12 through the fourth connecting channel 39 of the valve block 3. A stream of high-pressure oil will flow from the fourth connecting channel 39 to the first valve chamber 811 of the three-way hydraulic control valve 8.

[0070] Since the oil pressure in the first valve chamber 811 is much greater than that in the second valve chamber 812, the hydraulic oil in the first valve chamber 811 overcomes the resistance of the hydraulic oil in the second valve chamber 812 and the first spring 83, thereby pushing the first valve core 82 to flow toward the third connecting channel 38, thus connecting the first valve chamber 811 with the first delivery port, and the high-pressure oil in the fourth connecting channel 39 can flow to the third connecting channel 38 through the first control channel 301.

[0071] This prevents high-pressure oil from continuously entering the rod chamber 12 of the quick-change cylinder 1, and the high-pressure oil in the fourth connecting channel 39 is diverted to the third connecting channel 38. This makes it difficult for the hydraulic oil in the rod chamber 12 to build up enough oil pressure to overcome the weight of the attachment, thus making it difficult to push the piston 13 to contract and unlock the attachment. Meanwhile, some of the hydraulic oil flowing to the third connecting channel acts on the rodless chamber 11 of the quick-change cylinder 1, while some hydraulic oil flows through the solenoid valve 4 port and into the oil tank from the return port 32 of the valve block 3.

[0072] That is, by setting a three-way hydraulic control valve 8 between the third connecting channel 38 and the fourth connecting channel 39, when the attachment is suspended, the piston 13 of the quick-change cylinder 1 cannot retract effectively, and the attachment remains locked, thereby achieving the purpose of "suspended anti-unlocking" and further improving the safety of attachment replacement.

[0073] When the attachment is placed on the ground, its weight is directly borne by the ground. Compared to when the attachment is suspended in the air, the force required to push the piston in the quick-change cylinder 1 to contract is smaller, meaning the hydraulic oil pressure in the rod chamber 12 is also smaller.

[0074] Therefore, when the attachment is placed on the ground to unlock, the pressure difference of the hydraulic oil in the rod chamber 12 and the rodless chamber 11 is small, and the pressure difference of the hydraulic oil in the first valve chamber 811 and the second valve chamber 812 is also small. In this case, the sum of the force exerted by the hydraulic oil in the first valve chamber 811 on the first valve core 82 and the force exerted by the first spring 83 on the first valve core 82 will be greater than the force exerted by the hydraulic oil in the second valve chamber 812 of the three-way hydraulic control valve 8 on the first valve core 82; thus, the first valve core 82 continuously blocks the first output port 813 on the first valve body 81, that is, the first valve core 82 blocks the first control flow channel 301. This allows the hydraulic oil in the fourth connecting flow channel 39 to continuously flow into the rod chamber 12 of the quick-change cylinder 1 to push the piston 13 to contract, thereby achieving rapid unlocking of the attachment.

[0075] This means that those skilled in the art can control the stiffness coefficient of the first spring 83, so that the operator can only unlock the attachment when it is on the ground. When the attachment is suspended in the air, the operator cannot unlock it, thereby improving the safety of unlocking and replacing the attachment.

[0076] The embodiments of this application achieve the purpose of "lock suspension to prevent unlocking" by using a mechanical structure, without relying on monitoring settings such as pressure sensors and controllers, and have higher stability and security.

[0077] Example 3: This application discloses a quick-change solenoid valve assembly and hydraulic system.

[0078] The difference between Example 3 and Example 2 is as follows:

[0079] The three-way hydraulic control valve 8 is generally a low-flow valve, meaning it can only divert a small amount of high-pressure oil from the fourth connecting channel 39 to the third connecting channel 38. If the quick-change cylinder 1 is small, the excavator's attachments are lightweight, and the required fall protection force is not high, the three-way hydraulic control valve 8 can function well to prevent attachments from being unlocked in mid-air, thus improving the safety of attachment replacement.

[0080] However, when the quick-change cylinder 1 is large, the excavator's attachments are heavy, and the excavator requires a large fall protection force, the application of the three-way hydraulic control valve 8 becomes limited. Therefore, this embodiment further improves the quick-change solenoid valve assembly.

[0081] Reference Figure 10 and Figure 11 The quick-change solenoid valve assembly also includes a hydraulically controlled on / off valve 9, which is disposed within the valve block 3. The valve block 3 has a second control flow channel 302, one end of which is connected to the first working oil port 33, and the other end of which is connected to the second working oil port 34. The hydraulically controlled port of the hydraulically controlled on / off valve 9 is connected to the first output port 813 of the three-way hydraulically controlled valve 8. That is, one end of the hydraulically controlled on / off valve 9 is connected to the third connecting flow channel 38, and one end of the hydraulically controlled on / off valve 9 is connected to the fourth connecting flow channel 39.

[0082] High-pressure oil enters the hydraulic control port of the hydraulic control on / off valve 9 through the first output port 813, causing the hydraulic control on / off valve 9 to open the second control flow channel 302.

[0083] Reference Figure 11Specifically, the hydraulic control on / off valve 9 includes a second valve body 91, a second valve core 92, a second spring 93, and a second limiting block 94. The second valve core 92 divides the valve chamber of the second valve body 91 into a third valve chamber 912 and a fourth valve chamber 913. The hydraulic control port of the hydraulic control valve 9 is connected to the third valve chamber 912. The second valve body 91 has a first communication port 911 connected to the second control flow channel 302. The second spring 93 is disposed in the fourth valve chamber 913. The second limiting block 94 is fixed in the third valve chamber 912, and the second spring 93 forces the second valve core 92 to abut against the second limiting block 94, thereby blocking the first communication port 911 of the second valve body 91.

[0084] Reference Figure 11 The valve core is provided with a second communication port 921. High-pressure oil flows into the third valve chamber 912 of the hydraulic control valve 9 through the three-way hydraulic control valve 8. The high-pressure oil drives the valve core to compress the second spring 93, so that the second communication port 921 of the second valve core 92 is connected to the first communication port 911 of the second valve body 91.

[0085] The implementation principle of a hydraulic system according to an embodiment of this application is as follows:

[0086] Reference Figure 11 and Figure 12 As described in Example 2, if the attachment is suspended and the operator mistakenly operates the solenoid valve 4 to switch directions, the three-way hydraulic control valve 8 will guide the high-pressure oil in the fourth connecting channel 39 to the hydraulic port of the hydraulic control on / off valve 9. After the hydraulic oil enters the third valve chamber 912 of the second valve body 91, the hydraulic oil will exert a force on the second valve core 92 to overcome the force of the second spring 93 on the second valve core 92, causing the second valve core 92 to move. Thus, the second connecting port 921 of the second valve core 92 is connected to the first connecting port 911 of the second valve body 91, and the hydraulic control on / off valve 9 opens the second control channel 302. This allows the high-pressure oil in the fourth connecting channel 39 to flow to the third connecting channel 38 via the hydraulic control on / off valve 9 and the second control channel 302, thereby achieving the purpose of "preventing attachment from being suspended and unlocked," and further improving the safety of excavator operation.

[0087] The three-way hydraulic control valve 8 is generally a small flow valve, while the hydraulic control on / off valve 9 can be a large flow valve; thus adapting to the working conditions where the quick-change cylinder 1 is larger in size, the excavator's attachments are heavier, and the excavator requires greater fall protection force.

[0088] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A quick-change solenoid valve assembly, characterized in that: The system includes a valve block (3) and a solenoid valve (4). The valve block (3) has an internal flow channel. The solenoid valve (4) is a two-position four-way solenoid valve. The valve block (3) has an oil inlet (31), an oil return port (32), a first working oil port (33), and a second working oil port (34) connected to the solenoid valve (4). The oil inlet (31) is used to connect to an external variable hydraulic pump (2). The first working oil port (33) is used to connect to the rodless chamber (11) of the quick-change cylinder (1). The second working oil port (34) is used to connect to the rod chamber (12) of the quick-change cylinder (1). The solenoid valve (4) controls the oil inlet (31) to connect with the first working oil port (33) or the second working oil port (34) to drive the quick-change cylinder (1) to extend and retract; the valve block (3) also includes a load feedback oil port (35), which is connected with the second working oil port (34). The load feedback oil port (35) is externally connected to a variable hydraulic pump (2) to feed back the oil pressure in the rod chamber (12) to the variable hydraulic pump (2), so that the oil pressure output by the variable hydraulic pump (2) is greater than the oil pressure in the rod chamber (12); it also includes The valve includes a three-way hydraulic control valve (8), which is mounted on the valve block (3). The three-way hydraulic control valve (8) includes a first valve body (81), a first valve core (82), a first spring (83), and a first limiting block (84). The first valve core (82) divides the valve chamber of the first valve body (81) into a first valve chamber (811) and a second valve chamber (812). The first valve chamber (811) is connected to the first working port (33) of the valve block (3), and the second valve chamber (812) is connected to the second working port (34) of the valve block (3). The first valve body (81) is connected to the first valve cavity (811), the first spring (83) is disposed in the first valve cavity (811), the first limiting block (84) is fixed in the second valve cavity (812), the first spring (83) forces the first valve core (82) to abut against the first limiting block (84), so that the first valve core (82) blocks the first output port (813); the three-way hydraulic control valve (8) is used to guide the high pressure hydraulic oil at the second working oil port (34) to the first working oil port (33).

2. The quick-change solenoid valve assembly according to claim 1, characterized in that: It also includes a first check valve (5), which is disposed on the internal flow channel connecting the second working port (34) and the load feedback port (35); the first check valve (5) allows hydraulic oil to flow unidirectionally from the second working port (34) to the load feedback port (35).

3. The quick-change solenoid valve assembly according to claim 1, characterized in that: It also includes a pressure reducing valve (6), which is located in the internal flow channel between the solenoid valve (4) and the oil inlet (31), through which hydraulic oil flows to the solenoid valve (4).

4. The quick-change solenoid valve assembly according to claim 1, characterized in that: It also includes a hydraulic control check valve (7), which is disposed on the internal flow channel connecting the solenoid valve (4) and the first working port (33). The hydraulic control port of the hydraulic control check valve (7) is connected to the second working port (34). The hydraulic control check valve (7) allows hydraulic oil to flow unidirectionally to the first working port (33). When the oil pressure of the external rod chamber (12) is transmitted to the hydraulic control port of the hydraulic control check valve (7), the hydraulic oil flows through the first working port (33) of the valve block (3), the hydraulic control check valve (7) and the solenoid valve (4).

5. The quick-change solenoid valve assembly according to claim 1, characterized in that: The valve block (3) has a first control flow channel (301), one end of which is connected to the first output port (813), and the other end of which is connected to the first working oil port (33).

6. The quick-change solenoid valve assembly according to claim 1, characterized in that: It also includes a hydraulic control valve (9), which is disposed in the valve block (3); the valve block (3) is provided with a second control flow channel (302) inside, one end of the second control flow channel (302) is connected to the first working oil port (33), and the other end of the second control flow channel (302) is connected to the second working oil port (34); the hydraulic control valve (9) is disposed on the second control flow channel (302), and the hydraulic control port of the hydraulic control valve (9) is connected to the first output port (813) of the three-way hydraulic control valve (8); high pressure hydraulic oil enters the hydraulic control port of the hydraulic control valve (9) through the first output port (813), so that the hydraulic control valve (9) opens the second control flow channel (302).

7. The quick-change solenoid valve assembly according to claim 6, characterized in that: The hydraulic control on / off valve (9) includes a second valve body (91), a second valve core (92), and a second spring (93); the second valve core (92) divides the valve chamber of the second valve body (91) into a third valve chamber (912) and a fourth valve chamber (913), the hydraulic control port of the hydraulic control valve (9) is connected to the third valve chamber (912), and the second valve body (91) is provided with a first communication port (911) connected to the second control flow channel (302); the second spring (93) is disposed in the fourth valve chamber (913), and the second... The spring (93) forces the second valve core (92) to block the first communication port (911) of the second valve body (91); the second valve core (92) is provided with a second communication port (921), and the high pressure hydraulic oil flows into the third valve chamber (912) of the hydraulic control on / off valve (9) through the three-way hydraulic control valve (8). The high pressure hydraulic oil drives the second valve core (92) to compress the second spring (93) so that the second communication port (921) of the second valve core (92) is connected to the first communication port (911) of the second valve body (91).

8. The quick-change solenoid valve assembly according to claim 7, characterized in that: The hydraulic control on / off valve (9) also includes a second limiting block (94), which is fixed in the third valve chamber (912). The second spring (93) forces the second valve core (92) to abut against the second limiting block (94).

9. A hydraulic system, characterized in that: The system includes the quick-change solenoid valve assembly according to any one of claims 1-8, and further includes a quick-change cylinder (1) and a variable hydraulic pump (2), wherein the variable hydraulic pump (2) is connected to the quick-change cylinder (1) through the quick-change solenoid valve assembly.

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