An electro-hydraulic cylinder

Abstract

The utility model discloses a kind of electric hydraulic cylinders, belong to engineering machinery hydraulic technology field. Including oil cylinder assembly, frameless brushless motor assembly, bidirectional gear pump assembly and pipeline valve block assembly;Oil cylinder assembly includes oil cylinder barrel, and the lower end of oil cylinder barrel extends and forms the shell of frameless brushless motor assembly;By adopting the integrated structure that the lower end of oil cylinder barrel extends directly forms frameless brushless motor assembly shell, then stator is fixed with the interference fit of oil cylinder barrel inner wall by stator inner flange and stator outer flange, without additional motor mounting bracket;At the same time, bidirectional gear pump is directly fixed in the lower end of oil cylinder barrel by gear pump mounting flange, realizes the high integration of oil cylinder assembly, frameless brushless motor assembly, bidirectional gear pump assembly;Compared with traditional dispersed structure, the overall volume of the utility model can be effectively reduced, compact and simple structure, can be flexibly adapted to narrow installation scene, and then effectively improve space adaptability.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic technology for engineering machinery, and in particular to an electric hydraulic cylinder. Background Technology

[0002] As an actuator integrating mechanics, electricity, and hydraulics, the electric hydraulic cylinder is widely used in industrial automation, engineering machinery, aerospace and other fields due to its advantages such as large output force, high positioning accuracy and fast response speed. Its core function is to convert the rotational motion of the motor into the linear reciprocating motion of the hydraulic cylinder piston to drive the load to complete the specified action.

[0003] However, existing electric hydraulic cylinders still have many shortcomings in structural design and performance, making it difficult to meet the ever-increasing application demands. Traditional electric hydraulic cylinders mostly adopt a structure combining a framed motor and a hydraulic pump. Each component is set independently and assembled through connectors, resulting in a large overall size and loose structure. This not only occupies a lot of installation space but also reduces the adaptability of the equipment in confined spaces. At the same time, the transmission link of the independent structure is long, with many transmission gaps, which easily leads to low transmission efficiency and poor operational stability, affecting the action accuracy of the hydraulic cylinder. In terms of power transmission, the motor and hydraulic pump of existing devices often use belt, chain, or ordinary gear transmission methods. These methods have defects such as high transmission loss, high noise, and easy wear. After long-term use, transmission accuracy will decrease and maintenance frequency will increase, which may reduce the service life and operational reliability of the equipment. Utility Model Content

[0004] The purpose of this utility model is to solve the problems in the background art mentioned above, and to propose an electric hydraulic cylinder.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An electro-hydraulic cylinder includes a cylinder assembly, a frameless brushless motor assembly, a bidirectional gear pump assembly, and a pipeline valve block assembly; The hydraulic cylinder assembly includes a hydraulic cylinder barrel, and the lower end of the hydraulic cylinder barrel extends out to form the housing of the frameless brushless motor assembly; The frameless brushless motor assembly includes a stator and a rotor, with a rotor central shaft connected to the rotor, and the rotor and rotor central shaft connected in the stator by bearings; The stator is connected to an inner stator flange and an outer stator flange, both of which are connected inside the cylinder barrel of the hydraulic cylinder. The bidirectional gear pump assembly includes a bidirectional gear pump and a gear pump mounting flange. The bidirectional gear pump is mounted on the gear pump mounting flange, and the gear pump mounting flange is fixedly connected to the cylinder barrel. The output end of the bidirectional gear pump meshes with the central shaft of the rotor; The pipeline valve block assembly includes a balance valve, which is connected in series in the hydraulic circuit of the cylinder assembly; the frameless brushless motor assembly controls the speed and direction of rotation through an electronic commutator and controller, drives the bidirectional gear pump to rotate forward or reverse to output high-pressure oil, and then drives the piston of the cylinder assembly to extend or retract.

[0006] Preferably, the cylinder assembly further includes a cylinder rod and a guide sleeve, the guide sleeve being fixedly connected in the cylinder barrel, the piston being slidably connected in the cylinder barrel, and the piston being fixedly connected to the cylinder rod.

[0007] Furthermore, the pipeline valve block assembly also includes a small oil replenishment tank, an oil replenishment hose, a pump inlet steel pipe, a cylinder inlet steel pipe, a pump outlet steel pipe, and a cylinder outlet steel pipe; the small oil replenishment tank is connected to the pump inlet steel pipe via the oil replenishment hose, the pump inlet steel pipe is connected to the inlet of the bidirectional gear pump, the outlet of the bidirectional gear pump is connected to the inlet of the balance valve via the pump outlet steel pipe, the outlet of the balance valve is connected to the inlet of the cylinder via the cylinder inlet steel pipe, and the outlet of the cylinder is connected to the return port of the bidirectional gear pump via the cylinder outlet steel pipe.

[0008] Preferably, the stator is fixed to the inner wall of the cylinder barrel by an interference fit between the inner stator flange and the outer stator flange.

[0009] Preferably, the bearings are deep groove ball bearings, and the two bearings are respectively installed in the bearing holes of the inner stator flange and the outer stator flange.

[0010] Preferably, the bidirectional gear pump is detachably connected to the gear pump mounting flange by bolts.

[0011] Preferably, the balance valve is a hydraulically controlled one-way balance valve, used to achieve load maintenance, load control and safety assurance of the cylinder assembly.

[0012] Preferably, the stator of the frameless brushless motor assembly is composed of windings, and the rotor is composed of high-energy rare-earth permanent magnets.

[0013] Compared with the prior art, the present invention provides an electric hydraulic cylinder, which has the following beneficial effects: This invention utilizes an integrated structure where the lower end of the hydraulic cylinder extends directly to form the housing of the frameless brushless motor assembly. The stator is then fixed to the inner wall of the hydraulic cylinder via an interference fit using an inner stator flange and an outer stator flange, eliminating the need for an additional motor mounting bracket. Simultaneously, the bidirectional gear pump is directly fixed to the lower end of the hydraulic cylinder via a gear pump mounting flange, achieving a high degree of integration between the hydraulic cylinder assembly, the frameless brushless motor assembly, and the bidirectional gear pump assembly. Compared to traditional distributed structures, this invention effectively reduces the overall size, resulting in a compact and simple structure that can flexibly adapt to confined installation scenarios, thereby effectively improving space adaptability.

[0014] This invention utilizes a frameless brushless motor assembly as its power source. The stator is composed of windings, and the rotor is composed of high-energy rare-earth permanent magnets. Compared to traditional brushed motors, it offers advantages such as low energy consumption, excellent heat dissipation, fast response, no commutation sparks, and long service life. Furthermore, it employs a direct meshing transmission between the output spline shaft of a bidirectional gear pump and the internal spline of the rotor's central shaft. This results in a short transmission link, small clearance, and effectively improved transmission efficiency, while significantly reducing transmission losses and operating noise. Additionally, the stable support of the rotor's central shaft by deep groove ball bearings further enhances operational smoothness, reduces component wear, and effectively extends service life.

[0015] This invention connects a hydraulically controlled one-way balance valve in series in the hydraulic circuit. This balance valve can precisely regulate the pressure of high-pressure oil and has excellent locking performance. When the piston moves to the target position, it can automatically lock the hydraulic circuit to maintain the load stably for a long time. At the same time, when the load is abnormally overloaded, the balance valve can quickly trigger the safety protection mechanism to limit the hydraulic oil pressure from not exceeding the rated value, effectively preventing damage to pipelines, pumps, or cylinder barrels due to excessive pressure, thereby improving the safety and reliability of the hydraulic circuit. Attached Figure Description

[0016] Figure 1 An exploded view of an electric hydraulic cylinder proposed in this utility model; Figure 2 This is a cross-sectional view of an electric hydraulic cylinder proposed in this utility model; Figure 3 This is a schematic diagram of the structure of an electric hydraulic cylinder proposed in this utility model.

[0017] In the diagram: 1. Cylinder barrel; 2. Piston; 3. Cylinder rod; 4. Guide sleeve; 5. Stator inner flange; 6. Stator; 7. Rotor; 8. Stator outer flange; 9. Bearing; 10. Rotor central shaft; 11. Gear pump mounting flange; 12. Bidirectional gear pump; 13. Small oil tank; 14. Oil replenishment hose; 15. Pump inlet steel pipe; 16. Balance valve; 17. Cylinder inlet steel pipe; 18. Pump outlet steel pipe; 19. Cylinder outlet steel pipe. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0019] Reference Figures 1-3 An electric hydraulic cylinder includes a cylinder assembly, a frameless brushless motor assembly, a bidirectional gear pump assembly, and a pipeline valve block assembly; The hydraulic cylinder assembly includes a hydraulic cylinder barrel 1, and the lower end of the hydraulic cylinder barrel 1 extends out to form the housing of the frameless brushless motor assembly; The frameless brushless motor assembly includes a stator 6 and a rotor 7. A rotor central shaft 10 is connected to the rotor 7, and the rotor 7 and the rotor central shaft 10 are connected in the stator 6 by a bearing 9. The stator 6 is connected to the inner stator flange 5 and the outer stator flange 8, both of which are connected inside the cylinder barrel 1. The bidirectional gear pump assembly includes a bidirectional gear pump 12 and a gear pump mounting flange 11. The bidirectional gear pump 12 is mounted on the gear pump mounting flange 11, and the gear pump mounting flange 11 is fixedly connected to the cylinder barrel 1. The output end of the bidirectional gear pump 12 meshes with the rotor central shaft 10; The pipeline valve block assembly includes a balance valve 16, which is connected in series in the hydraulic circuit of the cylinder assembly; the frameless brushless motor assembly controls the speed and direction of rotation through an electronic commutator and controller, drives the bidirectional gear pump 12 to rotate forward or reverse to output high-pressure oil, and then drives the piston 2 of the cylinder assembly to extend or retract.

[0020] Reference Figure 1 It should be noted that the output spline shaft of the bidirectional gear pump 12 meshes with the internal spline of the rotor central shaft 10.

[0021] The hydraulic cylinder assembly also includes a cylinder rod 3 and a guide sleeve 4. The guide sleeve 4 is fixedly connected in the cylinder barrel 1, and the piston 2 is slidably connected in the cylinder barrel 1. The piston 2 is also fixedly connected to the cylinder rod 3.

[0022] The pipeline valve block assembly also includes a small oil replenishment tank 13, an oil replenishment hose 14, a pump inlet steel pipe 15, a cylinder inlet steel pipe 17, a pump outlet steel pipe 18, and a cylinder outlet steel pipe 19. The small oil replenishment tank 13 is connected to the pump inlet steel pipe 15 through the oil replenishment hose 14. The pump inlet steel pipe 15 is connected to the oil inlet of the bidirectional gear pump 12. The oil outlet of the bidirectional gear pump 12 is connected to the oil inlet of the balance valve 16 through the pump outlet steel pipe 18. The oil outlet of the balance valve 16 is connected to the oil inlet of the cylinder barrel 1 through the cylinder inlet steel pipe 17. The oil outlet of the cylinder barrel 1 is connected to the return port of the bidirectional gear pump 12 through the cylinder outlet steel pipe 19.

[0023] The stator 6 is fixed to the inner wall of the cylinder barrel 1 by interference fit through the inner stator flange 5 and the outer stator flange 8.

[0024] Bearing 9 is a deep groove ball bearing or a needle roller tapered bearing, and the two bearings 9 are respectively installed in the bearing holes of the inner stator flange 5 and the outer stator flange 8.

[0025] The bidirectional gear pump 12 is detachably connected to the gear pump mounting flange 11 by bolts.

[0026] The balance valve 16 is a hydraulically controlled one-way balance valve used to maintain the load, control the load, and ensure the safety of the cylinder assembly.

[0027] The stator 6 of the frameless brushless motor assembly consists of windings, and the rotor 7 consists of high-energy rare-earth permanent magnets.

[0028] Reference Figures 1-3 In actual use, the controller sends action commands to the frameless brushless motor assembly. The electronic commutator controls the speed and direction of the motor according to the commands. At this time, the rotor 7 of the frameless brushless motor assembly drives the rotor central shaft 10 to rotate. The rotor central shaft 10 drives the bidirectional gear pump 12 to rotate forward or in reverse through the meshing structure. The bidirectional gear pump 12 draws in hydraulic oil from the pump inlet steel pipe 15 and then outputs high-pressure oil to the balance valve 16 through the pump outlet steel pipe 18. After the balance valve 16 regulates the pressure of the high-pressure oil, the hydraulic oil is delivered to the oil inlet of the cylinder barrel 1 through the cylinder oil inlet steel pipe 17, which pushes the piston 2 to slide along the inner wall of the cylinder barrel 1, thereby driving the lever 3 to extend or retract. Reference Figures 1-3 The return oil in the cylinder barrel 1 flows back to the return port of the bidirectional gear pump 12 through the cylinder outlet steel pipe 19, completing the hydraulic circuit circulation.

[0029] It should be noted that when piston 2 moves to the target position, balance valve 16 automatically locks the hydraulic circuit to maintain the load; if the load is abnormal, balance valve 16 will trigger a safety protection mechanism to limit the hydraulic oil pressure and prevent damage to the device.

[0030] After the action is completed, a stop command is sent through the controller, the frameless brushless motor assembly stops running, the bidirectional gear pump 12 stops supplying oil, and the piston 2 can be reset to the initial position as needed.

[0031] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An electric hydraulic cylinder, characterized in that, This includes hydraulic cylinder assemblies, frameless brushless motor assemblies, bidirectional gear pump assemblies, and pipeline valve block assemblies; The cylinder assembly includes a cylinder barrel (1), and the lower end of the cylinder barrel (1) extends out to form the housing of the frameless brushless motor assembly; The frameless brushless motor assembly includes a stator (6) and a rotor (7), with a rotor central shaft (10) connected to the rotor (7), and the rotor (7) and the rotor central shaft (10) connected in the stator (6) by a bearing (9); The stator (6) is connected to an inner stator flange (5) and an outer stator flange (8), both of which are connected inside the cylinder barrel (1). The bidirectional gear pump assembly includes a bidirectional gear pump (12) and a gear pump mounting flange (11). The bidirectional gear pump (12) is mounted on the gear pump mounting flange (11), and the gear pump mounting flange (11) is fixedly connected to the cylinder barrel (1). The output end of the bidirectional gear pump (12) meshes with the rotor central shaft (10); The pipeline valve block assembly includes a balance valve (16), which is connected in series in the hydraulic circuit of the cylinder assembly; the frameless brushless motor assembly controls the speed and direction of rotation through an electronic commutator and controller, drives the bidirectional gear pump (12) to rotate forward or reverse to output high-pressure oil, thereby driving the piston (2) of the cylinder assembly to extend or retract.

2. An electric hydraulic cylinder according to claim 1, characterized in that, The cylinder assembly also includes a cylinder rod (3) and a guide sleeve (4). The guide sleeve (4) is fixedly connected in the cylinder barrel (1). The piston (2) is slidably connected in the cylinder barrel (1), and the piston (2) is fixedly connected to the cylinder rod (3).

3. An electric hydraulic cylinder according to claim 1, characterized in that, The pipeline valve block assembly also includes a small oil replenishment tank (13), an oil replenishment hose (14), a pump inlet steel pipe (15), a cylinder inlet steel pipe (17), a pump outlet steel pipe (18), and a cylinder outlet steel pipe (19). The small oil replenishment tank (13) is connected to the pump inlet steel pipe (15) through the oil replenishment hose (14). The pump inlet steel pipe (15) is connected to the inlet of the bidirectional gear pump (12). The outlet of the bidirectional gear pump (12) is connected to the inlet of the balance valve (16) through the pump outlet steel pipe (18). The outlet of the balance valve (16) is connected to the inlet of the cylinder barrel (1) through the cylinder inlet steel pipe (17). The outlet of the cylinder barrel (1) is connected to the return port of the bidirectional gear pump (12) through the cylinder outlet steel pipe (19).

4. An electric hydraulic cylinder according to claim 1, characterized in that, The stator (6) is fixed to the inner wall of the cylinder barrel (1) by interference fit between the inner stator flange (5) and the outer stator flange (8).

5. The electric hydraulic cylinder according to claim 1, characterized in that, The bearing (9) is a deep groove ball bearing, and the two bearings (9) are respectively installed in the bearing holes of the inner stator flange (5) and the outer stator flange (8).

6. The electric hydraulic cylinder according to claim 1, characterized in that, The bidirectional gear pump (12) is detachably connected to the gear pump mounting flange (11) by bolts.

7. The electric hydraulic cylinder according to claim 1, characterized in that, The balance valve (16) is a hydraulically controlled one-way balance valve, used to achieve load maintenance, load control and safety assurance of the cylinder assembly.

8. The electric hydraulic cylinder according to claim 1, characterized in that, The stator (6) of the frameless brushless motor assembly is composed of windings. The rotor (7) is composed of high-energy rare earth permanent magnets.

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