A hydraulic system with controllable action sequence

Abstract

The utility model relates to hydraulic drive technical field especially relates to a hydraulic system of action sequence controllable. Hydraulic system includes cylinder body, primary piston rod and secondary piston rod, and cylinder body forms primary cylinder chamber, and primary piston rod forms secondary cylinder chamber. Primary piston rod divides primary cylinder chamber into first rodless chamber and first rod chamber, and secondary piston rod divides secondary cylinder chamber into second rodless chamber and second rod chamber, and first rod chamber and second rod chamber are communicated. Cylinder body is communicated oil source through oil pipeline, and oil pipeline is provided with first valve group, second valve group and switch valve. Adopting the utility model, can realize two stage piston rod according to the action sequence from small to big and retract in turn according to the action sequence from big to small, satisfy special working condition demand.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic drive technology, and in particular to a hydraulic system with controllable action sequence. Background Technology

[0002] Hydraulic cylinders are the core actuators in hydraulic systems. They can convert hydraulic energy into mechanical energy and achieve linear reciprocating motion, and are widely used in various mechanical hydraulic systems.

[0003] Existing hydraulic cylinders can be divided into multi-stage hydraulic cylinders according to the data of the piston rod. In a conventional two-stage hydraulic cylinder, the action sequence of the first-stage piston and the second-stage piston is from large to small, extending in sequence and retracting in sequence, from small to large, to complete the multi-stage linear reciprocating motion of the hydraulic cylinder.

[0004] However, in actual operation, under certain working conditions, it is necessary to first move a small load to a designated position, and then move a large load to a designated position. The existing hydraulic cylinders cannot meet the action sequence of the above working conditions and cannot meet the actual operation requirements. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a hydraulic system with controllable action sequence, enabling two-stage piston rods to extend sequentially from small to large action sequence and retract sequentially from large to small action sequence, thus meeting the needs of special working conditions.

[0006] To solve the above-mentioned technical problems, this utility model provides a hydraulic system with controllable action sequence, including a cylinder body, a primary piston rod and a secondary piston rod. The cylinder body forms a primary cylinder cavity, and the primary piston rod is slidably connected to the primary cylinder cavity. The primary piston rod forms a secondary cylinder cavity, and the secondary piston rod is slidably connected to the secondary cylinder cavity.

[0007] The first-stage piston rod divides the first-stage cylinder chamber into a first rodless chamber and a first rod chamber, and the second-stage piston rod divides the second-stage cylinder chamber into a second rodless chamber and a second rod chamber, with the first rod chamber and the second rod chamber connected.

[0008] The second rod chamber is provided with a reset element that abuts against the second-stage piston rod;

[0009] The cylinder body is connected to an oil source through an oil pipeline. The oil pipeline is equipped with a first valve group, a second valve group, and a switching valve. The first valve group is located between the first rodless chamber and the oil source. The switching valve has a first valve port, a second valve port, and a third valve port. The first valve port is connected to the first rod chamber and the second rodless chamber. The second valve port is connected to the oil source. The second valve group is located between the third valve port and the oil source.

[0010] As an improvement to the above solution, the first valve group includes a first sequence valve, and the second valve group includes a second sequence valve;

[0011] Wherein, the oil inlet of the first sequence valve is connected to the oil source, and the oil outlet of the first sequence valve is connected to the first rodless chamber;

[0012] The oil inlet of the second sequence valve is connected to the oil source, and the oil outlet of the second sequence valve is connected to the third valve port.

[0013] As an improvement to the above solution, the first valve group further includes a first check valve, and the second valve group further includes a second check valve.

[0014] The inlet of the first check valve is connected to the first rodless chamber, the outlet of the first check valve is connected to the oil source, and the first sequence valve is connected in parallel with the first check valve.

[0015] The inlet of the second check valve is connected to the third valve port, the outlet of the second check valve is connected to the oil source, and the second sequence valve is connected in parallel with the second check valve.

[0016] As an improvement to the above scheme, the oil pipeline is also equipped with a pressure regulating overflow valve and a third check valve. The oil inlet of the pressure regulating overflow valve is connected to the first valve port, and the oil outlet of the pressure regulating overflow valve is connected to the second rodless chamber.

[0017] The inlet of the third check valve is connected to the second rodless chamber, and the outlet of the third check valve is connected to the first valve port.

[0018] As an improvement to the above solution, the oil pipeline is connected to the oil source via a reversing valve.

[0019] As an improvement to the above solution, the cylinder body includes a cylinder barrel and an end cap connected to the first end of the cylinder barrel, the piston end of the first-stage piston rod faces the end cap, and the push rod end of the first-stage piston rod is slidably connected to the second end of the cylinder barrel.

[0020] The end cap has a first oil port that communicates with the first rodless cavity, and the cylinder has a second oil port that communicates with the first rod cavity.

[0021] As an improvement to the above solution, a third oil port is formed at the push rod end of the secondary piston rod, and an oil inlet channel is formed inside the secondary piston rod. The third oil port is connected to the second rodless chamber through the oil inlet channel.

[0022] The push rod end of the first-stage piston rod has a fourth oil port, which connects the first rod chamber and the second rod chamber.

[0023] As an improvement to the above solution, the push rod end of the first-stage piston rod is formed with a stepped surface, and the inner side of the cylinder facing the first rod chamber is formed with a stop surface. When the first-stage piston rod extends, the stepped surface abuts against the stop surface.

[0024] As an improvement to the above scheme, the first-stage piston rod forms a rod end face on the side facing the first rod chamber, and the fourth oil port and the second oil port are located between the stepped surface and the rod end face.

[0025] As an improvement to the above solution, a cylinder head is installed on the push rod end of the first-stage piston rod, and a stepped shaft is formed on the side of the cylinder head facing the second-stage piston rod. The stepped shaft is coaxial with the push rod end of the second-stage piston rod, and the reset member is sleeved on the stepped shaft.

[0026] Implementing this utility model has the following beneficial effects:

[0027] The hydraulic system with controllable action sequence in this embodiment can switch the connection sequence between the first rodless chamber, the second rodless chamber and the oil source through the cooperation of the first valve group, the second valve group and the switching valve, so as to realize the sequential extension of the second-stage piston rod and the first-stage piston rod, and the sequential retraction of the first-stage piston rod and the second-stage piston rod.

[0028] Specifically, when it is necessary to extend the first-stage piston rod and the second-stage piston rod, the first valve group disconnects the first rodless chamber from the high-pressure oil port of the oil source, and the first and second valve ports of the switching valve cooperate to connect the first rod chamber and the second rodless chamber to the high-pressure oil port of the oil source. At this time, high-pressure oil enters the first rod chamber, the second rodless chamber and the second rod chamber. The pressure in the second rodless chamber is greater than the pressure in the second rod chamber, thereby pushing the second-stage piston rod to extend.

[0029] When the second-stage piston rod is fully extended, the first valve group connects the first rodless chamber to the high-pressure oil port of the oil source. At this time, high-pressure oil enters the first rodless chamber, and the pressure in the first rodless chamber is greater than the pressure in the first rod chamber, thereby pushing the first-stage piston rod to extend.

[0030] When the first-stage and second-stage piston rods need to retract, the first valve assembly connects the first rodless chamber to the low-pressure port of the oil source to allow oil to return from the first rodless chamber. Simultaneously, the switching valve, in conjunction with the second control valve, connects the first rod chamber and the second rodless chamber to the high-pressure port of the oil source, ensuring a continuous flow of high-pressure oil into all three chambers. This keeps the second-stage piston rod extended while maintaining a higher pressure in the first rod chamber than in the first rodless chamber, thus pushing the first-stage piston rod to retract.

[0031] When the first-stage piston rod is fully retracted, the first valve group disconnects the first rodless chamber from the oil source, and at the same time the switching valve connects the first rod chamber and the second rodless chamber to the low-pressure oil port of the oil source so that the second rodless chamber, the second rod chamber and the first rod chamber can return oil. Under the action of the reset force of the reset member, the second-stage piston rod is pushed to retract.

[0032] Therefore, the hydraulic system of this embodiment can realize the two-stage piston rods extending sequentially in an ascending order of motion and retracting sequentially in an descending order of motion, thus meeting the requirements of special working conditions. Attached Figure Description

[0033] Figure 1 This is one of the schematic diagrams of the cylinder structure of the hydraulic system in one embodiment of the present invention, wherein the piston rod is not extended;

[0034] Figure 2 This is a second schematic diagram of the cylinder structure of the hydraulic system in one embodiment of the present invention, wherein the secondary piston rod extends out;

[0035] Figure 3 This is the third schematic diagram of the cylinder structure of the hydraulic system in one embodiment of this utility model, wherein the first-stage piston rod extends out;

[0036] Figure 4 This is a schematic diagram showing the positional arrangement of the second oil port, the fourth oil port, and the first-stage rod chamber in one embodiment of this utility model;

[0037] Figure 5 This is a schematic diagram of the oil circuit layout of the hydraulic system in one embodiment of this utility model;

[0038] Figure 6 This is a schematic diagram of the valve port position of the switching valve in one embodiment of this utility model. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the following will describe this utility model in further detail with reference to the accompanying drawings. It is hereby declared that the terms "up," "down," "left," "right," "front," "back," "inner," and "outer," etc., appearing or about to appear in this document, are based solely on the accompanying drawings and are not intended to specifically limit this utility model.

[0040] The hydraulic system of this invention, with controllable action sequence, enables the two-stage piston rods to extend sequentially from small to large action sequence and retract sequentially from large to small action sequence, thus meeting the needs of special working conditions.

[0041] In one embodiment of this utility model, such as Figures 1 to 3As shown, the hydraulic system with controllable action sequence includes a cylinder body 1, a first-stage piston rod 2, and a second-stage piston rod 3. The cylinder body 1 forms a first-stage cylinder chamber 101, and the first-stage piston rod 2 is slidably connected to the first-stage cylinder chamber 101. The first-stage piston rod 2 forms a second-stage cylinder chamber 201, and the second-stage piston rod 3 is slidably connected to the second-stage cylinder chamber 201.

[0042] The first-stage piston rod 2 divides the first-stage cylinder chamber 101 into a first rodless chamber 71 and a first rod chamber 72. The second-stage piston rod 3 divides the second-stage cylinder chamber 201 into a second rodless chamber 73 and a second rod chamber 74. The first rod chamber 72 and the second rod chamber 74 are connected. The second rod chamber 74 is provided with a reset member 4 that abuts against the second-stage piston rod 3.

[0043] like Figure 5 As shown, the cylinder body 1 is connected to the oil source through the oil supply line 5. The oil supply line 5 is equipped with a first valve group 51, a second valve group 52 and a switching valve 53. The first valve group 51 is located between the first rodless chamber 71 and the oil source. The switching valve 53 has a first valve port 531, a second valve port 532 and a third valve port 533. The first valve port 531 is connected to the first rod chamber 72 and the second rodless chamber 73. The second valve port 532 is connected to the oil source. The second valve group 52 is located between the third valve port 533 and the oil source.

[0044] The hydraulic system with controllable action sequence in this embodiment can switch the connection sequence between the first rodless chamber 71, the second rodless chamber 73 and the oil source through the cooperation of the first valve group 51, the second valve group 52 and the switching valve 53, so as to realize the sequential extension of the second-stage piston rod 3 and the first-stage piston rod 2, and the sequential retraction of the first-stage piston rod 2 and the second-stage piston rod 3.

[0045] Specifically, when it is necessary to extend the first-stage piston rod 2 and the second-stage piston rod 3, the first valve group 51 disconnects the first rodless chamber 71 from the high-pressure oil port of the oil source, and the first valve port 531 and the second valve port 532 of the switching valve 53 cooperate to connect the first rod chamber 72 and the second rodless chamber 73 with the high-pressure oil port of the oil source. At this time, high-pressure oil enters the first rod chamber 72, the second rodless chamber 73 and the second rod chamber 74. The pressure of the second rodless chamber 73 is greater than the pressure of the second rod chamber 74, thereby pushing the second-stage piston rod 3 to extend.

[0046] When the second-stage piston rod 3 is fully extended, the first valve group 51 connects the first rodless chamber 71 to the high-pressure oil port of the oil source. At this time, high-pressure oil enters the first rodless chamber 71, and the pressure in the first rodless chamber 71 is greater than the pressure in the first rod chamber 72, thereby pushing the first-stage piston rod 2 to extend.

[0047] When the first-stage piston rod 2 and the second-stage piston rod 3 need to retract, the first valve group 51 connects the first rodless chamber 71 to the low-pressure port of the oil source, so that oil can return to the first rodless chamber 71. At the same time, the switching valve 53 cooperates with the second control valve to connect the first rod chamber 72 and the second rodless chamber 73 to the high-pressure port of the oil source, so that high-pressure oil can continuously enter the first rod chamber 72, the second rodless chamber 73 and the second rod chamber 74. While keeping the second-stage piston rod 3 in the extended state, the pressure in the first rod chamber 72 is greater than the pressure in the first rodless chamber 71, thereby pushing the first-stage piston rod 2 to retract.

[0048] When the first-stage piston rod 2 is fully retracted, the first valve group 51 disconnects the first rodless chamber 71 from the oil source, and at the same time, the oil supply line 5 connects the first rod chamber 72 and the second rodless chamber 73 so that the oil pressure in the second rodless chamber 73, the second rod chamber 74 and the first rod chamber 72 is reduced. Then, under the action of the reset force of the reset member 4, the second-stage piston rod 3 is pushed to retract.

[0049] Therefore, the hydraulic system of this embodiment can realize the two-stage piston rods extending sequentially in an ascending order of motion and retracting sequentially in an descending order of motion, thus meeting the requirements of special working conditions.

[0050] Optionally, such as Figure 5 and Figure 6 As shown, the switching valve 53 is a shuttle valve. The shuttle valve can automatically select the valve port with higher pressure between the second valve port 532 and the third valve port 533 to connect to the first valve port 531, thereby switching the connection state between the first rod chamber 72 and the second rodless chamber 73 and the valve assembly. When the piston rod extends, the first valve assembly 51 is connected, and the second valve assembly 52 is not connected. The shuttle valve connects the second valve port 532 to the first valve port 531, thereby providing high-pressure oil to push the second rodless chamber 73 to extend. When the piston rod retracts, high-pressure oil flows through the second valve assembly 52, and low-pressure oil flows through the first valve assembly 51. The shuttle valve connects the third valve port 533 to the first valve port 531, thereby providing the retraction oil pressure difference for the first-stage piston rod 2 and ensuring that the second-stage piston rod 3 remains extended.

[0051] In this embodiment, as Figure 5 As shown, the first valve group 51 includes a first sequence valve 511, and the second valve group 52 includes a second sequence valve 521. The oil inlet of the first sequence valve 511 is connected to an oil source, and the oil outlet of the first sequence valve 511 is connected to the first rodless chamber 71. Therefore, when the piston rod extends, the oil inlet sequence of the second rodless chamber 73 and the first rodless chamber 71 can be controlled by the first sequence valve 511 to ensure that high-pressure oil first enters the second rodless chamber 73 to complete the extension of the second-stage piston rod 3, and then the first sequence valve 511 is opened to send high-pressure oil into the first rodless chamber 71 to complete the extension of the first-stage piston rod 2.

[0052] The inlet of the second sequence valve 521 is connected to the oil source, and the outlet of the second sequence valve 521 is connected to the third valve port 533. Therefore, when the piston rod retracts, the second sequence valve 521 can be opened by high-pressure oil to send high-pressure oil through the switching valve 53 into the first rod chamber 72 and the second rodless chamber 73. This ensures that while the second-stage piston rod 3 remains extended, the pressure in the first rod chamber 72 is greater than the pressure in the first rodless chamber 71, thus pushing the first-stage piston rod 2 to retract.

[0053] Furthermore, such as Figure 5 As shown, the first valve group 51 further includes a first check valve 512, and the second valve group 52 further includes a second check valve 522. The inlet of the first check valve 512 is connected to the first rodless chamber 71, and the outlet of the first check valve 512 is connected to the oil source. The first sequence valve 511 is connected in parallel with the first check valve 512 so as to use the first check valve 512 to unidirectionally connect the first rodless chamber 71 and the oil source, ensuring that the high-pressure oil enters the second rodless chamber 73 and the first rodless chamber 71 in sequence when the piston rod extends. At the same time, it facilitates the return of hydraulic oil through the first check valve 512 when the first-stage piston rod 2 retracts, without being obstructed by the first sequence valve 511.

[0054] The inlet of the second check valve 522 is connected to the third valve port 533, and the outlet of the second check valve 522 is connected to the oil source. The second sequence valve 521 is connected in parallel with the second check valve 522.

[0055] It should be noted that, since the secondary piston rod 3 is located inside the primary piston rod 2, and the diameter of the secondary piston rod 3 is smaller than the diameter of the primary piston rod 2, the secondary piston rod 3 mainly bears a small load, while the primary piston rod 2 mainly bears a large load. In this embodiment, since the second rodless chamber 73 receives high-pressure oil before the first rodless chamber 71, to control the stability of the secondary piston rod 3 during its extension process, such as... Figure 5 As shown, the oil pipeline 5 is also equipped with a pressure regulating overflow valve 541 and a third check valve 542. The oil inlet of the pressure regulating overflow valve 541 is connected to the first valve port 531, and the oil outlet of the pressure regulating overflow valve 541 is connected to the second rodless chamber 73.

[0056] Furthermore, during the process of high-pressure oil being input into the second rodless chamber 73 via the switching valve 53, the high-pressure oil enters the second rodless chamber 73 via the pressure regulating relief valve 541. The pressure regulating relief valve 541 can limit the oil pressure of the high-pressure oil entering the second rodless chamber 73, thereby stabilizing the oil pressure in the second rodless chamber 73, thus improving the stability of the second-stage piston rod 3 when it extends, and preventing damage to the second-stage piston rod 3 or the second-stage cylinder chamber 201 due to excessive pressure.

[0057] The inlet of the third check valve 542 is connected to the second rodless chamber 73, and the outlet of the third check valve 542 is connected to the first valve port 531, so as to unidirectionally connect the second rodless chamber 73 and the first valve port 531. This allows the hydraulic oil to flow into the oil supply line 5 through the pipeline where the third check valve 542 is located when the secondary hydraulic rod retracts, thereby reducing the pressure of the second rodless chamber 73 without being obstructed by the pressure regulating relief valve 541.

[0058] In order to facilitate switching the extension and retraction of the piston rod, the oil supply line 5 is connected to the oil source through the reversing valve 55. The relative movement of the valve core and valve body of the reversing valve 55 is used to change the connection state of the oil supply line 5, thereby switching the extension or retraction of the piston rod.

[0059] As a specific example, such as Figure 5 As shown, the reversing valve 55 can be a three-position four-way solenoid valve. The right-position oil inlet passage of the three-position four-way solenoid valve is connected to the second valve port 532 of the switching valve 53 and the oil inlet port of the first sequence valve 511, while the left-position oil inlet passage is connected to the oil inlet port of the second sequence valve 521. When the piston rod needs to extend, the three-position four-way solenoid valve switches to the right position to sequentially introduce high-pressure oil into the second rodless chamber 73 and the first rodless chamber 71. When the piston rod needs to retract, the three-position four-way solenoid valve switches to the left position to send high-pressure oil through the second sequence valve 521 and the switching valve 53 into the first rod chamber 72 and the second rodless chamber 73, thereby ensuring that while the first rodless chamber 71 returns oil, high-pressure oil is input into the second rodless chamber 73, keeping the second-stage piston rod 3 extended. When the second-stage piston rod 3 retracts, the three-position four-way solenoid valve switches to the middle position so that the hydraulic oil in the second rodless chamber 73 returns to the oil supply line 5.

[0060] In this embodiment, as Figures 1 to 3 As shown, the cylinder body 1 includes a cylinder barrel 11 and an end cap 12 connected to the first end of the cylinder barrel 11. The piston end of the first-stage piston rod 2 faces the end cap 12, and the push rod end of the first-stage piston rod 2 is slidably connected to the second end of the cylinder barrel 11 so as to form a first rodless chamber 71 and a first rod chamber 72 on both sides of the first-stage piston rod 2, and to ensure that when the first-stage piston rod 2 extends, the effective force of the first rodless chamber 71 is greater than the effective force of the first rod chamber 72, thereby realizing the differential extension of the first-stage piston rod 2.

[0061] The end cap 12 has a first oil port 711, which communicates with the first rodless chamber 71. The cylinder 11 has a second oil port 721, which communicates with the first rod chamber 72. High-pressure oil can enter the first rodless chamber 71 from the outlet of the first sequence valve 511 and the first oil port 711, and enter the first rod chamber 72 from the first valve port 531 and the second oil port 721 of the switching valve 53, thus completing the extension action of the first-stage piston rod 2. Alternatively, hydraulic oil can flow from the first oil port 711 to the first check valve 512, and from the second oil port 721 to the switching valve 53, thus completing the return oil action of the first-stage cylinder chamber 101.

[0062] It should be noted that the end cap 12 is embedded in the first end of the cylinder 11, and a retaining ring 121 is provided between the end cap 12 and the cylinder 11. The retaining ring 121 can be used to position the end cap 12 axially. At the same time, the end cap 12 is connected to a pressure plate 122 by bolts. The pressure plate 122 is embedded in the cylinder 11 and abuts against the retaining ring 121. The end cap 12 is fixed to the first end of the cylinder 11 by the cooperation of the pressure plate 122 and the retaining ring 121.

[0063] To ensure the sealing performance of the first rodless chamber 71 and the first rod chamber 72, a sealing ring 62 is arranged between the end cap 12 and the cylinder 11 to seal the connection gap between the end cap 12 and the cylinder 11 and prevent hydraulic oil from leaking from the end cap 12 and the cylinder 11; a sealing ring 62 is arranged between the piston end of the first-stage piston rod 2 and the cylinder 11 to seal the connection gap between the first-stage piston rod 2 and the cylinder 11 and prevent the first rod chamber 72 and the first rodless chamber 71 from communicating with each other; a sealing ring 62 is arranged between the push rod end of the first-stage piston rod 2 and the cylinder 11.

[0064] Guide rings 61 are arranged between the piston end of the first-stage piston rod 2 and the cylinder 11, and between the push rod end of the first-stage piston rod 2 and the cylinder 11, to facilitate relative sliding between the first-stage piston rod 2 and the cylinder 11.

[0065] The push rod end of the secondary piston rod 3 has a third oil port 731, and an oil inlet channel 31 is formed inside the secondary piston rod 3. The third oil port 731 is connected to the second rodless chamber 73 through the oil inlet channel 31. The push rod end of the primary piston rod 2 has a fourth oil port 741, which is connected to the first rod chamber 72 and the second rod chamber 74. High-pressure oil can enter the second rodless chamber 73 from the second valve port 532, the third oil port 731, and the oil inlet channel 31 of the switching valve 53, and enter the second rod chamber 74 from the second oil port 721 and the fourth oil port 741 to complete the extension action of the secondary piston rod 3. Alternatively, hydraulic oil can flow from the third oil port 731 to the switching valve 53, and from the fourth oil port 741 and the second oil port 721 to the switching valve 53 to complete the return oil action of the secondary cylinder chamber 201.

[0066] In some alternative embodiments, such as Figures 1 to 3 As shown, the push rod end of the first-stage piston rod 2 has a stepped surface 211, and the inner side of the cylinder 11 facing the first rod chamber 72 has a stop surface 111. When the first-stage piston rod 2 extends, the stepped surface 211 abuts against the stop surface 111. By utilizing the cooperation between the stepped surface 211 of the first-stage piston rod 2 and the stop surface 111 of the cylinder 11, the extension stroke of the first-stage piston rod 2 is limited, ensuring that the first-stage piston rod 2 can move to the target position and guaranteeing the movement accuracy of the first-stage piston rod 2. At the same time, it avoids the first-stage piston rod 2 from overtraveling and reduces the risk of damage to the first-stage piston rod 2.

[0067] In this embodiment, to ensure that the process of high-pressure oil entering the second rod chamber 74 from the first rod chamber 72 is unobstructed, such as... Figures 1 to 4 As shown, the first-stage piston rod 2 has a rod end face 221 on the side facing the first rod chamber 72. The fourth oil port 741 and the second oil port 721 are located between the stepped surface 211 and the rod end face 221. During the extension of the first-stage piston rod 2, since the stepped surface 211 abuts against the stop surface 111 of the cylinder 11, the fourth oil port 741 located between the stepped surface 211 and the rod end face 221 will not move to the back of the stop surface 111 of the cylinder 11, thus ensuring that the fourth oil port 741 can always communicate with the first rod chamber 72. At the same time, the second oil port 721 located between the stepped surface 211 and the rod end face 221 will also not be blocked by the piston rod of the first-stage piston rod 2, thus ensuring that the second oil port 721 can always communicate with the first rod chamber 72. This ensures that the hydraulic oil can enter the first rod chamber 72 and the second rod chamber 74, or flow out from the second rod chamber 74 and the first rod chamber 72, without being blocked by the movement of the first-stage piston rod 2.

[0068] Furthermore, to further ensure that the piston end of the first-stage piston rod 2 does not block the second oil port 721, the end cap 12 forms a rodless end face 123 on the side facing the first rodless chamber 71. The distance between the fourth oil port 741 and the rod end face 221 is D1, and the distance between the second oil port 721 and the rodless end face 123 is D2, where D1 is greater than or equal to D2.

[0069] In an optional embodiment, the reset member 4 is a compression spring. When the secondary piston rod 3 extends, the reset member 4 is compressed by the piston end of the secondary piston rod 3 and stores elastic force. After the hydraulic oil flows back in the second rodless chamber 73 and the second rod chamber 74, the elastic force of the reset member 4 acts on the piston end of the secondary piston rod 3 to push the secondary piston rod 3 to retract.

[0070] To ensure the effective reset of the secondary piston rod 3 by the reset component 4, such as Figures 1 to 3As shown, a cylinder head 23 is installed on the push rod end of the first-stage piston rod 2. A stepped shaft 231 is formed on the side of the cylinder head 23 facing the second-stage piston rod 3. The stepped shaft 231 is coaxial with the push rod end of the second-stage piston rod 3. The reset member 4 is sleeved on the stepped shaft 231 to ensure that the reset member 4 can always remain coaxial with the push rod end of the second-stage piston rod 3. This allows the reset force of the reset member 4 on the second-stage piston rod 3 to be transmitted along the axial direction of the second-stage piston rod 3, ensuring the reset accuracy of the second-stage piston rod 3, while avoiding the generation of lateral forces that would affect the service life of the reset member 4.

[0071] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this invention, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A hydraulic system with controllable action sequence, characterized in that, The system includes a cylinder body, a primary piston rod, and a secondary piston rod. The cylinder body forms a primary cylinder chamber, and the primary piston rod is slidably connected to the primary cylinder chamber. The primary piston rod forms a secondary cylinder chamber, and the secondary piston rod is slidably connected to the secondary cylinder chamber. The first-stage piston rod divides the first-stage cylinder chamber into a first rodless chamber and a first rod chamber, and the second-stage piston rod divides the second-stage cylinder chamber into a second rodless chamber and a second rod chamber, with the first rod chamber and the second rod chamber connected. The second rod chamber is provided with a reset element that abuts against the second-stage piston rod; The cylinder body is connected to an oil source through an oil pipeline. The oil pipeline is equipped with a first valve group, a second valve group, and a switching valve. The first valve group is located between the first rodless chamber and the oil source. The switching valve has a first valve port, a second valve port, and a third valve port. The first valve port is connected to the first rod chamber and the second rodless chamber. The second valve port is connected to the oil source. The second valve group is located between the third valve port and the oil source.

2. The hydraulic system with controllable action sequence according to claim 1, characterized in that, The first valve group includes a first sequence valve, and the second valve group includes a second sequence valve; Wherein, the oil inlet of the first sequence valve is connected to the oil source, and the oil outlet of the first sequence valve is connected to the first rodless chamber; The oil inlet of the second sequence valve is connected to the oil source, and the oil outlet of the second sequence valve is connected to the third valve port.

3. The hydraulic system with controllable action sequence according to claim 2, characterized in that, The first valve group further includes a first check valve, and the second valve group further includes a second check valve; The inlet of the first check valve is connected to the first rodless chamber, the outlet of the first check valve is connected to the oil source, and the first sequence valve is connected in parallel with the first check valve. The inlet of the second check valve is connected to the third valve port, the outlet of the second check valve is connected to the oil source, and the second sequence valve is connected in parallel with the second check valve.

4. The hydraulic system with controllable action sequence according to any one of claims 1 to 3, characterized in that, The oil pipeline is also equipped with a pressure regulating overflow valve and a third check valve. The oil inlet of the pressure regulating overflow valve is connected to the first valve port, and the oil outlet of the pressure regulating overflow valve is connected to the second rodless chamber. The inlet of the third check valve is connected to the second rodless chamber, and the outlet of the third check valve is connected to the first valve port.

5. The hydraulic system with controllable action sequence according to claim 1, characterized in that, The oil pipeline is connected to the oil source via a reversing valve.

6. The hydraulic system with controllable action sequence according to claim 1, characterized in that, The cylinder body includes a cylinder barrel and an end cap connected to the first end of the cylinder barrel. The piston end of the first-stage piston rod faces the end cap, and the push rod end of the first-stage piston rod is slidably connected to the second end of the cylinder barrel. The end cap has a first oil port that communicates with the first rodless cavity, and the cylinder has a second oil port that communicates with the first rod cavity.

7. The hydraulic system with controllable action sequence according to claim 6, characterized in that, The push rod end of the secondary piston rod has a third oil port, and an oil inlet channel is formed inside the secondary piston rod. The third oil port is connected to the second rodless chamber through the oil inlet channel. The push rod end of the first-stage piston rod has a fourth oil port, which connects the first rod chamber and the second rod chamber.

8. The hydraulic system with controllable action sequence according to claim 7, characterized in that, The push rod end of the first-stage piston rod has a stepped surface, and the inner side of the cylinder facing the first rod chamber has a stop surface. When the first-stage piston rod extends, the stepped surface abuts against the stop surface.

9. The hydraulic system with controllable action sequence according to claim 8, characterized in that, The first-stage piston rod forms a rod end face on the side facing the first rod chamber, and the fourth oil port and the second oil port are located between the stepped surface and the rod end face.

10. The hydraulic system with controllable action sequence according to claim 1, characterized in that, A cylinder head is installed on the push rod end of the first-stage piston rod. A stepped shaft is formed on the side of the cylinder head facing the second-stage piston rod. The stepped shaft is coaxial with the push rod end of the second-stage piston rod. The reset component is sleeved on the stepped shaft.

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