Hydraulic screw motor-mechanical linear actuator

Abstract

The hydraulic screw motor-mechanical linear actuator comprises a shell chamber, end support bearings, a main screw, a plurality of auxiliary screws, a nut type sleeve, a piston rod, a sealing ring, a buffer gasket and the like. During operation, high-pressure hydraulic oil is delivered by an external hydraulic circuit to drive the main and auxiliary screws to rotate, i.e. to form a hydraulic screw motor inside to drive the mechanical device to move, and the extension and retraction speed of the piston rod can be controlled by changing the direction and flow size of the hydraulic circuit. The structure of the present application is reasonable and compact, and the asymmetry problem existing in the oil circuit on both sides of the extension and retraction process of the traditional one-way hydraulic cylinder piston is ingeniously avoided by a simple structure, and the disadvantages of the pure electric cylinder, such as the need for additional installation of a motor drive and a speed reduction device, size limitation, weak bearing of the electric cylinder and low power-to-weight ratio, are avoided. While realizing high-speed linear motion and convenient control, the actuator is also ensured to have high power density operation and can provide greater driving force to cope with heavy load and impact occasions.

Description

Technical Field

[0001] This invention belongs to the field of mechatronic transmission technology, specifically relating to a hydraulic screw motor-mechanical linear actuator. Background Technology

[0002] In recent years, with the rapid development of modern industry and machinery manufacturing, linear actuators, as a common and widely used component in mechanical equipment for driving load motion, have become increasingly important. Their core function is to convert rotary motion into linear motion. Traditional linear actuators typically use hydraulic cylinders to drive piston rods to transmit motion. Hydraulic cylinder actuators have advantages such as high power density and strong load-bearing capacity, and are widely used in large equipment fields such as engineering machinery, marine and aerospace industries. However, common hydraulic cylinders are mainly asymmetrical cylinders, and the flow mismatch caused by the difference in the area of ​​their two chambers has restricted the development of this device.

[0003] With the development of electromechanical and electrical automation technologies in mechanical equipment, the application areas of electromechanical actuators (EMAs), which consist of electric cylinders composed of permanent magnet brushless motors and several sensors, are constantly expanding, and high-precision electric cylinders are receiving increasing attention. However, EMA actuators have low power density and weak load-bearing capacity, making them difficult to apply in high-power, large-scale engineering machinery applications. Furthermore, electromechanical linear actuators require additional motors, gear (or belt) transmission systems, couplings, etc., which increases the structural size of the linear actuator and makes them unsuitable for space-constrained applications. Summary of the Invention

[0004] To address the shortcomings of the aforementioned linear actuators, this invention provides a hydraulic screw motor-mechanical linear actuator, which improves upon existing linear actuator devices. Its simple structure cleverly avoids the asymmetry problem of the oil circuits on both sides of the piston extension and retraction process in traditional unidirectional hydraulic cylinders, as well as the drawbacks of pure electric cylinders, such as the need for an additional motor drive, increased mechanical space, weak load-bearing capacity, and low power-to-weight ratio. The structure of this invention eliminates the need for additional transmission components such as motors, gears, and couplings, making it suitable for use in smaller spaces. This hydraulic motor-mechanical linear actuator achieves high-speed linear motion and convenient control while ensuring high power density operation and providing greater driving force to cope with heavy-load and impact applications, thus solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A hydraulic screw motor-mechanical linear actuator includes: a front end cover, an oil baffle ring, a buffer gasket, a rear end cover, a piston rod, a main screw, and a housing chamber. The front end cover and the rear end cover are bolted to the left and right sides of the housing chamber. It also includes an auxiliary screw, a flange, an oil inlet port, a nut-type sleeve, and an oil return port. The main screw and the auxiliary screw mesh with each other and are installed in the axially constrained cavity composed of a nut-type sleeve and a flange. The working conditions of the hydraulic screw motor are formed in the sealed space formed by the inner cavity of the outer shell and the inner cavity of the piston rod. Together, they form a hydraulic screw motor. The main screw is axially fixed in the outer shell cavity and can only rotate. The outer shell cavity and the piston rod are respectively provided with oil inlet and oil return ports and connected to the inner cavity of the hydraulic screw motor. The piston rod extends and retracts axially in the outer shell cavity.

[0006] Preferably, it includes an end support bearing, through which the main screw is axially fixed within the housing cavity. The auxiliary screw is installed inside a nut-type sleeve and meshes with the main screw, rotating relative to it. A flange is fixedly connected inside the nut-type sleeve. The auxiliary screw is axially constrained and installed on the nut-type sleeve. A piston rod is connected to the nut-type sleeve. The axial movement of the nut-type sleeve drives the extension and retraction of the piston rod. A buffer gasket is installed on the shoulder of the housing cavity. The housing cavity and the piston rod are respectively provided with an oil inlet and an oil return port and connected to the meshing chambers of the main screw and the auxiliary screw.

[0007] Preferably, there are multiple auxiliary screws.

[0008] Multiple auxiliary screws are evenly distributed.

[0009] The piston rod has a cavity for housing the main screw, and the oil return port is located at the end of the piston rod and connected to the cavity.

[0010] The auxiliary screws on multiple hydraulic screw motors can be added or removed around the main screw according to actual working conditions and usage requirements. After installing flanges that match the size of the auxiliary screws, the main screw, auxiliary screws, flanges, and nut-type sleeves are combined to form multi-screw motors of different specifications.

[0011] A sealing ring is installed between the flange and the nut-type sleeve.

[0012] Compared with the prior art, the hydraulic screw motor-mechanical linear actuator provided by this invention has the following advantages: 1. This invention eliminates the need for a motor. Instead, it uses an external hydraulic circuit to deliver high-pressure hydraulic oil to drive the main and auxiliary screws, effectively creating an internal hydraulic screw motor to move the mechanical device. The extension, retraction, and movement speed of the piston rod can be controlled by changing the direction and flow rate of the hydraulic circuit. This saves space for installing motors, couplings, and gear transmission devices. The reduced size of the linear actuator makes it suitable for applications with limited installation space.

[0013] 2. Structurally, this invention transforms the traditional process of a hydraulic circuit pushing a piston to achieve extension and retraction into an external hydraulic circuit driving the main and auxiliary screws to rotate. The auxiliary screw moves along the axis of the main screw to further achieve piston rod extension and retraction. This invention cleverly avoids the asymmetry problem of the hydraulic circuits on both sides during the piston extension and retraction process of a traditional unidirectional hydraulic cylinder.

[0014] 3. Replacing the electric drive system with a hydraulic system solves the problems of pure electric cylinders requiring an additional motor drive, and the drawbacks of electric cylinders such as weak load-bearing capacity and low power-to-weight ratio. While achieving high-speed linear motion, it also ensures that the linear actuator can operate with high power density and provide greater driving force to cope with impact, heavy load, and shock-prone environments. Attached Figure Description

[0015] Figure 1 This is a cross-sectional structural diagram of the present invention; Figure 2 This is a three-dimensional structural diagram of the present invention; Figure 3 For the present invention Figure 1 3D structural diagram of the main and auxiliary screws and the 9-screw motor at point A in the middle; Figure 4 For the present invention Figure 1 3D structural diagram of the main and auxiliary screws and the 5-screw motor at point A in the middle; Figure 5 For the present invention Figure 4 Schematic diagram of the cross section of the 5-screw motor; Figure 6 For the present invention Figure 1 Enlarged view of the main and auxiliary screw mating structure at point A.

[0016] Reference numerals: 1-Front end cover, 2-Oil baffle ring, 3-Buffer gasket, 4-Secondary screw, 5-Flange, 6-Piston rod, 7-Rear end cover, 8-Ear ring, 9-End support bearing, 10-Oil inlet port, 11-Main screw, 12-Nut sleeve, 13-Sealing ring, 14-Outer shell chamber, 15-Oil return port. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1—6, a hydraulic screw motor-mechanical linear actuator, comprising a front end cover 1, an oil retaining ring 2, a buffer gasket 3, a secondary screw 4, a flange 5, a piston rod 6, a rear end cover 7, an ear ring 8, an end support bearing 9, an oil inlet port 10, a main screw 11, a nut-type sleeve 12, a sealing ring 13, an outer shell chamber 14, and an oil return port 15. The main screw 11 is axially fixed within the outer casing chamber 14 by passing through the end support bearing 9, allowing only rotational movement. The auxiliary screw 4 is installed inside the nut-type sleeve 12 and meshes with the main screw 11, allowing for relative rotational movement. The flange 5 is fixedly connected to both ends of the nut-type sleeve 12 by pins. Shafts are provided at both ends of the auxiliary screw 4, and the shafts of the auxiliary screw 4 pass through the circular holes on the flange 5 to constrain the auxiliary screw 4 and prevent it from axially disengaging from the nut-type sleeve 12. The piston rod 6 is bolted to the nut-type sleeve 12, and a housing for the main screw is provided inside the piston rod 6. The cavity of rod 11, the lug 8 end of piston rod 6 is provided with a return oil interface 15 connected to the cavity, the movement of nut sleeve 12 drives the extension and retraction of piston rod 6, buffer pad 3 is installed on the shoulder of main screw 11, front end cover 1 and rear end cover 7 are bolted to the left and right sides of outer shell cavity 14, oil inlet 10 is provided in the outer shell cavity 14 adjacent to buffer pad 3 and connects to the rodless cavity inside, oil inlet 10 and return oil interface 15 are connected to the external hydraulic circuit, and sealing ring 13 is provided between flange 5 and nut sleeve 12.

[0019] When there are multiple auxiliary screws 4, they are preferably evenly distributed, such as... Figure 3-5 .

[0020] like Figure 1-2 The power source is an external hydraulic source, provided by the oil circuit of an external hydraulic system connected to the oil inlet port 10 and the oil return port 15, without the need for an additional external motor drive on the actuator structure.

[0021] The main screw 11, auxiliary screw 4, nut-type sleeve 12, and flange 5 cooperate with each other to form the working conditions of a hydraulic screw motor in the sealed space formed by the outer shell chamber 14 and the piston rod 6. Together, they form a hydraulic screw motor. High-pressure hydraulic oil is supplied from the external hydraulic circuit through the oil inlet port 10 and the oil return port 15 to drive this hydraulic screw motor. The rotation of the hydraulic screw motor drives the mechanical device to move.

[0022] The nut-type sleeve 12 is connected to the piston rod 6. The auxiliary screw 4 moves spirally upward in the main screw 11, driving the extension and retraction of the piston rod 6. By changing the direction of the hydraulic circuit and the flow rate of the hydraulic system, the rotation direction and speed of the main screw 11 can be controlled, thereby controlling the forward and reverse rotation and speed of the hydraulic screw motor, and further controlling the extension and retraction of the external piston rod and its movement speed.

[0023] like Figure 3-5The number of auxiliary screws 4 on the hydraulic screw motor can be increased or decreased according to actual working conditions and usage requirements. After installing flanges 5 that match the number of auxiliary screws 4, the main screws 11, auxiliary screws 4, flanges 5, and nut-type sleeves 12 can be combined to form multi-screw motors of different specifications.

[0024] Working Principle: When using this hydraulic screw motor-mechanical actuator, the oil inlet 10 and oil return 15 are connected to the external hydraulic system via oil pipes to ensure a closed-loop hydraulic path. During operation, high-pressure hydraulic oil is delivered to the rodless chamber through the external hydraulic circuit, thereby driving the main and auxiliary screws to rotate relative to each other. Internally, the main screw 11, auxiliary screw 4, nut-type sleeve 12, and flange 5 work together to form a hydraulic screw motor that drives the auxiliary screw 4 to rotate and move linearly along the axis of the main screw 11. The nut-type sleeve 12 on the auxiliary screw 4 also moves linearly. The nut-type sleeve 12 is connected to the piston rod 6, which drives the mechanical device to move linearly. By changing the direction and flow rate of the hydraulic circuit, the extension, retraction, and movement speed of the piston rod 6 can be controlled. When pressurized oil is input into the oil inlet 10, the oil return 15 flows back; when pressurized oil is input into the oil return 15, the oil inlet 10 flows back, thereby realizing the extension and retraction of the piston rod 6.

[0025] Although the embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms without departing from the spirit and scope of the claims of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A hydraulic screw motor-mechanical linear actuator, comprising: The front cover (1), oil baffle ring (2), buffer pad (3), rear cover (7), piston rod (6), main screw (11), outer shell chamber (14), the front cover (1) and the rear cover (7) are bolted to the left and right sides of the outer shell chamber (14), characterized in that it also includes a secondary screw (4), flange (5), end support bearing (9), oil inlet (10), nut-type sleeve (12), and oil return (15); The main screw (11) and the auxiliary screw (4) mesh with each other and are installed in the axially constrained cavity formed by the nut sleeve (12) and the flange (5). The piston rod (6) has a cavity to accommodate the main screw (11). The working conditions of the hydraulic screw motor are formed in the sealed space formed by the outer shell chamber (14) and the piston rod (6), which together form a hydraulic screw motor. The main screw (11) passes through the end support bearing (9) to achieve axial fixation in the outer shell chamber (14) and can only rotate. The main screw (11) and the auxiliary screw (4) are driven to rotate by the external hydraulic oil circuit. The auxiliary screw (4) moves along the axis of the main screw (11). The piston rod is further extended and retracted. The outer shell chamber (14) and the piston rod (6) are respectively provided with an oil inlet port (10) and an oil return port (15) and connected to the inner cavity of the hydraulic screw motor. The piston rod (6) extends and retracts axially in the outer shell chamber (14). The piston rod (6) is connected to the nut sleeve (12). The axial movement of the nut sleeve (12) drives the extension and retraction of the piston rod (6). The buffer pad (3) is installed on the shoulder of the outer shell chamber (14) and is set opposite to the side of the nut sleeve (12) where the nut sleeve (12) and the piston rod (6) are connected. The oil baffle ring (2) is located on the side of the end support bearing (9) close to the buffer pad (3).

2. The hydraulic screw motor-mechanical linear actuator according to claim 1, characterized in that, The auxiliary screw (4) is installed inside the nut-type sleeve (12) and meshes with the main screw (11), rotating relative to each other. The flange (5) is fixedly connected inside the nut-type sleeve (12). The auxiliary screw (4) is axially constrained and installed in the nut-type sleeve (12). The outer shell chamber (14) and the piston rod (6) are respectively provided with an oil inlet port (10) and an oil return port (15) and are connected to the meshing chambers of the main screw (11) and the auxiliary screw (4).

3. The hydraulic screw motor-mechanical linear actuator according to claim 2, characterized in that, There are multiple auxiliary screws (4).

4. A hydraulic screw motor-mechanical linear actuator according to claim 3, characterized in that, The multiple auxiliary screws (4) are evenly distributed.

5. A hydraulic screw motor-mechanical linear actuator according to claim 2, characterized in that, The oil return port (15) is located at the rod end of the piston rod (6) and connected to the cavity.

6. A hydraulic screw motor-mechanical linear actuator according to claim 3, characterized in that, Multiple auxiliary screws (4) on the hydraulic screw motors can be added or removed around the main screw (11) according to actual working conditions and usage requirements. After installing flanges (5) that match the size of the auxiliary screws (4), the main screw (11), auxiliary screws (4), flanges (5), and nut-type sleeves (12) are combined to form multi-screw motors of different specifications.

7. A hydraulic screw motor-mechanical linear actuator according to claim 2, characterized in that, A sealing ring (13) is provided between the flange (5) and the nut sleeve (12).

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