Stroke-controllable electric hydraulic cylinder and multi-hydraulic-cylinder synchronous movement control system

Abstract

The utility model discloses a stroke-controllable electric hydraulic cylinder and a multi-hydraulic-cylinder synchronous movement control system, and relates to the technical field of hydraulic cylinders, the stroke-controllable electric hydraulic cylinder comprises a hydraulic cylinder body, a power unit and a control unit, and the hydraulic cylinder body comprises a cylinder barrel, a piston rod, a rear cover and a displacement sensor assembly; the displacement sensor assembly comprises a sensor body arranged in the fixed mounting cavity, a guide rod arranged in the mounting cavity, a measuring line arranged in the guide rod in a penetrating mode and a measuring head arranged on the measuring line, one end of the guide rod is located in the mounting cavity, and the other end of the guide rod extends into the piston rod and is in sliding fit with the piston rod; a channel for the measuring line to penetrate through is arranged in the guide rod, one end of the measuring line is connected with the sensor body, the other end of the measuring line penetrates through the channel and then extends into the piston rod, the measuring head is arranged at the end, extending into the piston rod, of the measuring line, and the measuring head is fixedly connected to the inner wall of the piston rod. By the adoption of the technical scheme, the device has the advantages of being small in size, convenient to install, controllable in stroke, capable of being controlled and used in a single-branch or multi-branch synchronous mode, capable of meeting the high-precision requirement and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic cylinders, in particular to a controllable stroke electric hydraulic cylinder and a multi-hydraulic cylinder synchronous motion control system. Background Art

[0002] Ordinary hydraulic cylinders are actuators in hydraulic transmission systems. They require an external hydraulic power unit to provide pressurized oil to achieve reciprocating motion. If stroke control is required, detection and control devices must be installed externally to achieve stroke control. This product has disadvantages such as bulky size, complex control and inconvenient use. Such installation and control methods are not available in many occasions.

[0003] At present, the scheme for synchronous use of multiple cylinders is generally to use one hydraulic oil channel to enter the synchronous diverter and output multiple equally divided oil channels. However, the accuracy that can be achieved by the general synchronous diverter is 2-5%, which is too low to achieve higher accuracy.

[0004] Therefore, the present application provides a controllable stroke electric hydraulic cylinder and a multi-hydraulic cylinder synchronous motion system to solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to address the defects and shortcomings in the prior art. The utility model provides a controllable stroke electric hydraulic cylinder and a multi-hydraulic cylinder synchronous motion control system, which has the advantages of small size, easy installation, controllable stroke, single-cylinder or multi-cylinder synchronous control, and the ability to meet high-precision requirements.

[0006] The utility model provides a controllable stroke electric hydraulic cylinder adopting a technical solution: a controllable stroke electric hydraulic cylinder, comprising a hydraulic cylinder body, a power unit and a control unit, wherein the hydraulic cylinder body comprises:

[0007] A cylinder barrel, wherein a receiving cavity is provided inside the cylinder barrel, the cylinder barrel has a first end and a second end, and an oil inlet and an oil outlet are respectively provided at the first end and the second end of the cylinder barrel;

[0008] A piston rod, one end of which is movably disposed in the mounting cavity of the cylinder barrel, and the other end of which extends out of the accommodating cavity from the first end of the cylinder barrel along the length direction of the cylinder barrel;

[0009] A piston ring, fixedly sleeved on one end of the piston rod located in the mounting cavity, and the piston ring is located between the oil inlet and the oil outlet;

[0010] A rear cover, fixedly disposed at the second end of the cylinder, for sealing the second end of the cylinder, and having an installation cavity formed therein;

[0011] A displacement sensor assembly is arranged in the installation cavity and is used to measure the displacement distance of the piston rod. The displacement sensor assembly comprises a sensor body arranged in the fixed installation cavity, a guide rod arranged in the installation cavity, a measuring line inserted in the guide rod, and a measuring head arranged on the measuring line. The guide rod is arranged along the length direction of the piston rod, one end of the guide rod is located in the installation cavity, the other end of the guide rod extends into the piston rod and slidably cooperates with the piston rod, a channel for the measuring line to pass through is arranged inside the guide rod, one end of the measuring line is connected to the sensor body, and the other end of the measuring line extends into the piston rod after passing through the channel, the measuring head is fixedly connected to one end of the measuring line extending into the piston rod, and the measuring head is fixedly connected to the inner wall of the piston rod;

[0012] The power unit is used to drive the piston rod to extend or retract relative to the cylinder barrel. The control unit is electrically connected to the power unit, and the control unit is used to control the action of the power unit.

[0013] Preferably, a connecting portion is provided on one side of the rear cover facing the second end of the cylinder, the connecting portion is adapted to the size of the cylinder, the connecting portion extends into the installation cavity through the second end of the cylinder, and the connecting portion and the cylinder are interference fit.

[0014] Preferably, a through hole for the guide rod to pass through is provided on the connecting portion of the rear cover, and a sealing ring is sleeved on the guide rod, and the sealing ring is used to seal the gap between the guide rod and the through hole.

[0015] Preferably, the rear cover is provided with a lateral opening connected to the installation cavity, the lateral opening is located on the side of the rear cover away from the cylinder barrel, and the rear cover is provided with an end cover for closing the lateral opening, and a fastener is provided between the end cover and the rear cover to achieve a detachable connection between the end cover and the rear cover through the fastener.

[0016] Preferably, the number of the fasteners is several groups, the several groups of fasteners are evenly distributed along the circumferential direction of the rear cover and the end cover, and the several groups of fasteners cooperate to achieve a detachable connection between the end cover and the rear cover.

[0017] Preferably, the fastener includes a first screw hole opened on the rear cover, a second screw hole opened on the end cover, and a fastening screw for cooperating with the first screw hole and the second screw hole, the first screw hole and the second screw hole are arranged opposite to each other, the first screw hole and the second screw hole are both arranged along the length direction of the cylinder, and one end of the fastening screw passes through the second screw hole and is threadedly connected to the first screw hole.

[0018] Preferably, the power unit includes an oil pump and a drive motor arranged on the cylinder barrel, and the two sides of the oil pump are respectively connected with an oil inlet pipe and an oil outlet pipe, the end of the oil inlet pipe away from the oil pump is connected to the oil inlet port on the cylinder barrel, and the end of the oil outlet pipe away from the oil pump is connected to the oil outlet port on the cylinder barrel, the drive motor is located on the side of the oil pump facing the first end of the cylinder barrel, and the drive motor is used to drive the oil pump to operate.

[0019] Preferably, the control unit includes a controller disposed on the rear cover of the drive motor, the controller is electrically connected to the displacement sensor assembly and the drive motor, and the controller monitors and calculates the extension and retraction stroke of the piston rod in real time through the displacement sensor assembly.

[0020] Preferably, a sealing ring is provided on the cylinder barrel, the sealing ring is provided at the first end of the cylinder barrel and is used to seal the first end of the cylinder body, and a through hole for the piston rod to pass through is opened in the middle of the sealing ring.

[0021] The present application also provides a multi-hydraulic cylinder synchronous motion system, including a main control system and multiple controllable stroke electric hydraulic cylinders as described above, wherein the main control system is electrically connected to the control units of the multiple controllable stroke electric hydraulic cylinders to achieve real-time monitoring of the multiple controllable stroke electric hydraulic cylinders and adjustment of synchronization.

[0022] After adopting the above technical solution, the beneficial effects of the utility model are:

[0023] 1. This application passes the other end of the measuring line connected to the sensor body through the guide rod and then fixes it to the inner wall of the piston rod through the measuring head, so that when the piston rod is displaced relative to the cylinder barrel, it drives the measuring head to move synchronously, thereby changing the length of the measuring line, and then the sensor body can judge the displacement of the piston rod according to the change in the length of the measuring line, thereby realizing accurate measurement of the displacement of the piston rod. Compared with the hydraulic cylinder in the prior art, this application embeds the sensor assembly into the hydraulic cylinder assembly, so that the displacement of the piston rod is not easily affected by the external environment, with high accuracy, small size, and easy installation, which can meet the needs of high-precision occasions;

[0024] 2. The present application is electrically connected to the control units of multiple controllable stroke electric hydraulic cylinders through a main control system, so that the controllers in each electric hydraulic cylinder can communicate with each other and adjust the speed of the motor to control the speed of the cylinder in real time, thereby achieving dynamic synchronization of multiple electric hydraulic cylinders. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model 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 described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 It is a schematic diagram of the overall structure of this embodiment;

[0027] Figure 2 is a cross-sectional view of this embodiment;

[0028] Figure 3 It is a schematic diagram used to reflect the matching relationship between the rear cover, the end cover and the fastener;

[0029] Explanation of the accompanying drawings: 1. Hydraulic cylinder body; 11. Cylinder barrel; 111. Accommodating chamber; 112. First end; 113. Second end; 114. Oil inlet; 115. Oil outlet; 116. Sealing ring; 12. Piston rod; 13. Piston ring; 14. Back cover; 141. Mounting chamber; 142. Connecting portion; 143. End cover; 144. Fastener; 1441. First screw hole; 1442. Second screw hole; 1443. Fastening screw; 15. Displacement sensor assembly; 151. Sensor body; 152. Guide rod; 1521. Channel; 153. Measuring line; 154. Measuring head; 155. Sealing ring; 2. Power unit; 21. Oil pump; 22. Drive motor; 23. Oil inlet pipe; 24. Oil outlet pipe; 3. Control unit. DETAILED DESCRIPTION

[0030] The following will be combined with the attached embodiment of the present utility model Figure 1-3 , clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] It should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "back", "side", "circumferential" and the like in the present invention indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. In addition, the words "first", "second" and the like are only used to distinguish multiple components or structures with the same or similar structures, and do not represent any special limitation on the setting order or connection relationship.

[0032] This embodiment relates to a controllable stroke electric hydraulic cylinder, referring to Figures 1 to 3 , including a hydraulic cylinder body 1, a power unit 2 and a control unit 3, wherein the hydraulic cylinder body 1 includes a cylinder barrel 11, a piston rod 12, a piston ring 13, a rear cover 14 and a displacement sensor assembly.

[0033] An accommodating chamber 111 is disposed inside the cylinder 11 . The cylinder 11 has a first end 112 and a second end 113 . An oil inlet 114 and an oil outlet 115 are disposed at the first end 112 and the second end 113 of the cylinder 11 , respectively.

[0034] One end of the piston rod 12 is movably disposed in the mounting cavity 141 of the cylinder 11 , that is, one end of the piston rod 12 can slide relative to the cylinder 11 , and the other end of the piston rod 12 extends out of the accommodating cavity 111 from the first end 112 of the cylinder 11 along the length direction of the cylinder 11 .

[0035] The rear cover 14 is fixedly disposed at the second end 113 of the cylinder 11 , and is used to seal the second end 113 of the cylinder 11 . An installation cavity 141 is disposed inside the rear cover 14 .

[0036] The displacement sensor assembly is fixedly arranged in the installation cavity 141, and is used to accurately measure the displacement distance of the piston rod 12. It includes a sensor body 151 fixedly arranged in the installation cavity 141, a guide rod 152 arranged in the installation cavity 141, a measuring line 153 passing through the guide rod 152, and a measuring head 154 arranged on the measuring line 153, wherein the guide rod 152 is arranged along the length direction of the piston rod 12, one end of the guide rod 152 is located in the installation cavity 141, the other end of the guide rod 152 extends into the piston rod 12 and slidably cooperates with the piston rod 12, and a channel 1521 for the measuring line 153 to pass through is arranged inside the guide rod 152, one end of the measuring line 153 is connected to the sensor body 151, and the other end of the measuring line 153 passes through the channel 1521 and extends into the piston rod 12, the measuring head 154 is fixedly connected to one end of the measuring line 153 extending into the piston rod 12, and the measuring head 154 is fixedly connected to the inner wall of the piston rod 12.

[0037] The power unit 2 is used to drive the piston rod 12 to extend or retract relative to the cylinder 11, and the control unit 3 is electrically connected to the power unit 2, and the control unit 3 is used to control the action of the power unit 2.

[0038] The control unit 3 controls the action of the power unit 2 so that the piston rod 12 can move relative to the cylinder 11, that is, at this time, the end of the piston rod 12 extending outside the cylinder 11 moves toward or away from the cylinder 11 (retracts or extends), thereby driving the measuring head 154 to move synchronously, and the measuring head 154 drives the measuring line 153 to lengthen or shorten, so that the length of the measuring line 153 changes, and then the sensor body 151 can judge the movement displacement of the piston rod 12 according to the change in the length of the measuring line 153, thereby realizing the accurate measurement of the movement displacement of the piston rod 12, that is, the stroke of the piston rod 12 can be controlled. The overall volume is small, the installation is convenient, and it can meet the needs of high-precision occasions.

[0039] Furthermore, a connecting portion 142 is provided on one side of the rear cover 14 facing the second end 113 of the cylinder 11. The connecting portion 142 is adapted to the size of the cylinder 11, and the connecting portion 142 extends into the installation cavity 141 through the second end 113 of the cylinder 11, and the connecting portion 142 and the cylinder 11 are interference fit.

[0040] By setting the connecting portion 142 on the rear cover 14, the assembly between the rear cover 14 and the cylinder barrel 11 is facilitated, and the interference fit between the connecting portion 142 and the cylinder barrel 11 ensures the sealing effect of the rear cover 14 on the second end 113 of the cylinder barrel 11, so that the hydraulic oil in the cylinder barrel 11 is not easy to flow into the installation cavity 141 of the rear cover 14.

[0041] Furthermore, a through hole is formed on the connecting portion 142 of the rear cover 14 for the guide rod 152 to pass through, and a sealing ring 155 is sleeved on the guide rod 152. The sealing ring 155 is located in the accommodating cavity 111 and is used to seal the gap between the guide rod 152 and the through hole.

[0042] The gap between the guide rod 152 and the through hole is sealed by the sealing ring 155 , so that when the power unit 2 provides hydraulic oil to the cylinder 11 , the hydraulic oil in the cylinder 11 is difficult to enter the installation cavity 141 of the rear cover 14 , thereby ensuring the sealing of the cylinder 11 .

[0043] Furthermore, the rear cover 14 is provided with a lateral opening connected to the installation cavity 141, and the lateral opening is located on the side of the rear cover 14 away from the cylinder 11, and the rear cover 14 is provided with an end cover 143 for closing the lateral opening, and a fastener 144 is provided between the end cover 143 and the rear cover 14 to achieve a detachable connection between the end cover 143 and the rear cover 14 through the fastener 144.

[0044] In this embodiment, the number of fasteners 144 is several groups, and the several groups of fasteners 144 are evenly distributed along the circumferential direction of the rear cover 14 and the end cover 143, and the several groups of fasteners 144 cooperate to achieve a detachable connection between the end cover 143 and the rear cover 14.

[0045] Specifically, the fastener 144 includes a first screw hole 1441 opened on the rear cover 14, a second screw hole 1442 opened on the end cover 143, and a fastening screw 1443 for cooperating with the first screw hole 1441 and the second screw hole 1442. The first screw hole 1441 and the second screw hole 1442 are arranged opposite to each other. The first screw hole 1441, the second screw hole 1442 and the fastening screw 1443 are all arranged along the length direction of the cylinder 11, and one end of the fastening screw 1443 passes through the second screw hole 1442 and is threadedly connected to the first screw hole 1441.

[0046] Through the cooperation between the first screw hole 1441 , the second screw hole 1442 and the fastening screw 1443 , a detachable connection between the end cover 143 and the rear cover 14 is achieved, thereby facilitating the inspection and replacement of the sensor body 151 .

[0047] Furthermore, the power unit 2 includes an oil pump 21 and a drive motor 22 arranged on the cylinder barrel 11, and the two sides of the oil pump 21 are respectively connected to an oil inlet pipe 23 and an oil outlet pipe 24, the end of the oil inlet pipe 23 away from the oil pump 21 is connected to the oil inlet port 114 of the cylinder barrel 11, and the end of the oil outlet pipe 24 away from the oil pump 21 is connected to the oil outlet port 115 of the cylinder barrel 11, and the drive motor 22 is located on the side of the oil pump 21 facing the second end 113 of the cylinder barrel 11, and the drive motor 22 is used to drive the operation of the oil pump 21.

[0048] It can be understood that the oil pump 21 is driven by the driving motor 22 to operate, so that the hydraulic oil in the oil pump 21 enters the oil inlet pipe 23 and then enters the accommodating chamber 111 through the oil inlet port 114, driving the piston rod 12 to move relative to the cylinder 11. At this time, the hydraulic oil located in the other end of the cylinder 11 enters the oil outlet pipe 24 through the oil outlet port 115 under the action of the piston and then flows back to the oil pump 21, thereby realizing the recycling of the hydraulic oil, and then the piston rod 12 can be extended or retracted relative to the cylinder body.

[0049] Furthermore, the control unit 3 includes a controller disposed on the rear cover of the drive motor 22, the controller is electrically connected to the displacement sensor assembly and the drive motor 22, and the controller monitors and calculates the extension and retraction stroke of the piston rod (12) in real time through the displacement sensor assembly.

[0050] The displacement sensor assembly is used to accurately measure the extension and retraction displacements of the piston rod 12 and transmit the data to the controller. The controller adjusts the rotation speed of the drive motor 22 in real time, thereby achieving accurate control of the extension and retraction strokes of the piston rod 12.

[0051] Furthermore, a sealing ring 116 is provided on the cylinder 11 . The sealing ring 116 is provided at the first end 112 of the cylinder 11 and is used to seal the first end 112 of the cylinder body. A through hole is provided in the middle of the sealing ring 116 for the piston rod 12 to pass through.

[0052] The first end 112 and the second end 113 of the cylinder 11 are sealed by the cooperation of the sealing ring 116 and the rear cover 14, thereby ensuring the sealing of the cylinder body, so that the hydraulic oil provided by the power unit 2 to the cylinder 11 is not easy to leak.

[0053] In addition, this embodiment also provides a multi-hydraulic cylinder synchronous motion control system, including a main control system and multiple controllable stroke electric hydraulic cylinders as described above, the main control system is electrically connected to the control units 3 of the multiple controllable stroke electric hydraulic cylinders to achieve real-time monitoring of the multiple controllable stroke electric hydraulic cylinders and adjustment of the synchronization degree.

[0054] The controllers of multiple electric hydraulic cylinders are controlled by the main control system, so that the controller can adjust the rotation speed of the drive motor 22 accordingly according to the piston rod movement displacement detected by the displacement sensor assembly, thereby realizing the adjustment of the synchronization accuracy of the multiple electric hydraulic cylinders, that is, the multiple electric hydraulic cylinders can be extended or retracted synchronously with high synchronization accuracy.

[0055] The above is only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. A controllable stroke electric hydraulic cylinder, characterized in that: The invention comprises a hydraulic cylinder body (1), a power unit (2) and a control unit (3), wherein the hydraulic cylinder body (1) comprises: A cylinder barrel (11), wherein a receiving chamber (111) is provided inside the cylinder barrel (11), the cylinder barrel (11) having a first end (112) and a second end (113), and an oil inlet (114) and an oil outlet (115) are respectively provided at the first end (112) and the second end (113) of the cylinder barrel (11); A piston rod (12), one end of which is movably disposed in the accommodating chamber (111) of the cylinder barrel (11), and the other end of which extends out of the accommodating chamber (111) from the first end (112) of the cylinder barrel (11) along the length direction of the cylinder barrel (11); A piston ring (13) is fixedly sleeved on one end of the piston rod (12) located in the mounting cavity (141), and the piston ring (13) is located between the oil inlet (114) and the oil outlet (115); a rear cover (14), fixedly mounted on the second end (113) of the cylinder (11), used for sealing the second end (113) of the cylinder (11), and having an installation cavity (141) formed therein; and A displacement sensor assembly is arranged in the installation cavity (141) and is used to measure the displacement distance of a piston rod (12). The displacement sensor assembly comprises a sensor body (151) arranged in the fixed installation cavity (141), a guide rod (152) arranged in the installation cavity (141), a measuring line (153) passing through the guide rod (152), and a measuring head (154) arranged on the measuring line (153). The guide rod (152) is arranged along the length direction of the piston rod (12). One end of the guide rod (152) is located in the installation cavity (141). The guide rod (152) is arranged along the length direction of the piston rod (12). 2) extends into the piston rod (12) and is slidably matched with the piston rod (12), a channel (1521) is provided inside the guide rod (152) for allowing the measuring line (153) to pass through, one end of the measuring line (153) is connected to the sensor body (151), and the other end of the measuring line (153) passes through the channel (1521) and then extends into the piston rod (12), the measuring head (154) is fixedly connected to the end of the measuring line (153) extending into the piston rod (12), and the measuring head (154) is fixedly connected to the inner wall of the piston rod (12); The power unit (2) is used to drive the piston rod (12) to extend or retract relative to the cylinder (11), the control unit (3) is electrically connected to the power unit (2), and the control unit (3) is used to control the action of the power unit (2).

2. The controllable stroke electric hydraulic cylinder according to claim 1, characterized in that: A connecting portion (142) is provided on one side of the rear cover (14) facing the second end (113) of the cylinder barrel (11); the connecting portion (142) is adapted to the size of the cylinder barrel (11); the connecting portion (142) extends into the installation cavity (141) through the second end (113) of the cylinder barrel (11); and the connecting portion (142) and the cylinder barrel (11) are in interference fit.

3. The controllable stroke electric hydraulic cylinder according to claim 2, characterized in that: A through hole for the guide rod (152) to pass through is provided on the connecting portion (142) of the rear cover (14), and a sealing ring (155) is sleeved on the guide rod (152), and the sealing ring (155) is used to seal the gap between the guide rod (152) and the through hole.

4. The controllable stroke electric hydraulic cylinder according to claim 1, characterized in that: The rear cover (14) is provided with a lateral opening connected to the installation cavity (141), the lateral opening being located on a side of the rear cover (14) away from the cylinder barrel (11), and the rear cover (14) is provided with an end cover (143) for closing the lateral opening, and a fastener (144) is provided between the end cover (143) and the rear cover (14) so ​​as to realize a detachable connection between the end cover (143) and the rear cover (14) through the fastener (144).

5. The controllable stroke electric hydraulic cylinder according to claim 4, characterized in that: The number of the fasteners (144) is several groups, the several groups of fasteners (144) are evenly distributed along the circumferential direction of the rear cover (14) and the end cover (143), and the several groups of fasteners (144) cooperate to achieve a detachable connection between the end cover (143) and the rear cover (14).

6. The controllable stroke electric hydraulic cylinder according to claim 5, characterized in that: The fastener (144) comprises a first screw hole (1441) formed on the rear cover (14), a second screw hole (1442) formed on the end cover (143), and a fastening screw (1443) for cooperating with the first screw hole (1441) and the second screw hole (1442), wherein the first screw hole (1441) and the second screw hole (1442) are arranged opposite to each other, the first screw hole (1441) and the second screw hole (1442) are both arranged along the length direction of the cylinder (11), and one end of the fastening screw (1443) passes through the second screw hole (1442) and is threadedly connected to the first screw hole (1441).

7. The controllable stroke electric hydraulic cylinder according to claim 1, characterized in that: The power unit (2) comprises an oil pump (21) and a drive motor (22) arranged on the cylinder barrel (11); the two sides of the oil pump (21) are respectively connected with an oil inlet pipe (23) and an oil outlet pipe (24); the end of the oil inlet pipe (23) away from the oil pump (21) is connected to an oil inlet port (114) on the cylinder barrel (11); the end of the oil outlet pipe (24) away from the oil pump (21) is connected to an oil outlet port (115) on the cylinder barrel (11); the drive motor (22) is located on a side of the oil pump (21) facing the first end (112) of the cylinder barrel (11), and the drive motor (22) is used to drive the oil pump (21) to operate.

8. The controllable stroke electric hydraulic cylinder according to claim 1, characterized in that: The control unit (3) comprises a controller arranged on a rear cover of the drive motor (22), the controller being electrically connected to the displacement sensor assembly and the drive motor (22), and the controller monitoring and calculating in real time the extension and retraction stroke of the piston rod (12) through the displacement sensor assembly.

9. The controllable stroke electric hydraulic cylinder according to claim 1, characterized in that: The cylinder barrel (11) is provided with a sealing ring (116), which is arranged at the first end (112) of the cylinder barrel (11) and is used to seal the first end (112) of the cylinder body, and a through hole for the piston rod (12) to pass through is opened in the middle of the sealing ring (116).

10. A multi-hydraulic cylinder synchronous motion control system, characterized in that: It comprises a main control system and a plurality of controllable-stroke electric hydraulic cylinders as described in any one of claims 1 to 9, wherein the main control system is electrically connected to the control units of the plurality of controllable-stroke electric hydraulic cylinders to achieve real-time monitoring of the plurality of controllable-stroke electric hydraulic cylinders and adjustment of synchronization.

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