Digital swing hydraulic cylinder

Abstract

The invention discloses a digital oscillating cylinder which comprises a ball screw transmission structure, a worm and gear transmission structure, a cylinder barrel structure, a servo motor and an encoder. The lead screw nut is connected with a wear-resisting guide sliding rail in the first cylinder barrel through a wear-resisting guide block. An output shaft of the screw rod is rotationally connected to the cylinder body; the three-position four-way reversing valve is integrated in the second cylinder barrel, and the position and the opening degree of a valve element are controlled by a servo motor. And a hollow shaft encoder is arranged on the screw rod output shaft and is used for measuring the rotating speed of the screw rod output shaft. The hydraulic valve is integrated in the cylinder body, the servo motor achieves adjustment of the rotating speed and the rotating direction of the lead screw output shaft by controlling the opening degree of the valve element and the position of the valve element, and the hollow shaft encoder is additionally arranged at the output end of the lead screw output shaft so that the input rotating speed of the servo motor can be adjusted; and the rotating speed of the screw rod output shaft can be controlled more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic cylinders, and specifically relates to a digital swing hydraulic cylinder. Background Art

[0002] Swing hydraulic cylinders are widely used in fields that require limited rotational motion and high torque, such as automobiles, construction, aerospace, etc. Specifically, it can be used for the swing of the working frame of an aerial work platform vehicle, the swing positioning of the drill arm of mining equipment, agricultural equipment, the tire or track steering of road equipment, the swing of actuators such as a sweeper forklift, and the flipping of the trash can of a garbage truck, etc. At present, the most main structure of the spiral swing hydraulic cylinder is a double - spiral structure, which uses a large - lead screw pair to convert the linear motion of the hydraulic cylinder piston into the rotational motion of the output shaft. So far, many patents have made improvements to the existing swing hydraulic cylinders. The Chinese patent application with the publication number CN112431807A discloses a swing hydraulic cylinder controlled by an electro - hydraulic actuator; the Chinese patent application with the publication number CN219345123U discloses a linear reciprocating hydraulic cylinder with relative rotation between the cylinder barrel and the piston rod; the Chinese patent application with the publication number CN117432674A discloses an embedded digital ball screw swing hydraulic cylinder; the Chinese patent application with the publication number CN113819108B discloses a digital screw swing hydraulic cylinder.

[0003] As can be seen from the above analysis, traditional hydraulic cylinders have the functions of positioning, speed regulation, and guiding control. However, the realization of these functions depends on the coordinated use of various fluid control components (such as pressure control valves, flow control valves, servo valves, and directional control valves, etc.). The main drawbacks are: complex structure, high price, difficult operation and maintenance, high requirements for the technical level of operators, and at the same time, the lack of the ability to directly connect to a computer for control. Summary of the Invention

[0004] Aiming at the above - mentioned existing technical deficiencies, the purpose of the present invention is to provide a digital hydraulic swing bar with high output accuracy and high transmission efficiency, which can realize the micro - feed and rapid feed of the swing angle.

[0005] To solve the above deficiencies, the present invention adopts the following technical solution: A digital hydraulic swing bar includes a first cylinder barrel provided with a front end cover and a second cylinder barrel provided with a rear end cover, and the first cylinder barrel and the second cylinder barrel are fixedly connected;

[0006] The left - hand opening of the first cylinder barrel is rotatably installed with a lead - screw output shaft through a first bearing and a first bearing seat. The lead - screw end of the lead - screw output shaft is arranged inside the first cylinder barrel and is fitted with a lead - screw nut. The outer wall of the lead - screw nut is nested and fixed with a wear - resistant guide block, and the inner wall of the first cylinder barrel is provided with a wear - resistant guide rail adapted to the wear - resistant guide block and for it to slide left and right;

[0007] A servo motor and a rotatable driven gear are provided on the rear end cover. The output end of the servo motor is connected with a worm, the worm drives a turbine to rotate, the turbine is coaxially connected with the driven gear. An oil cavity is formed inside the second cylinder barrel, and a three-position four-way directional control valve and a corresponding hydraulic oil circuit communicating with the oil cavity are integrated. An oil cylinder piston is arranged in the oil cavity. The left end of the oil cylinder piston is fixedly connected with a wear-resistant guide block. A rack adapted to the driven gear is arranged at the end of a spool arranged inside the three-position four-way directional control valve;

[0008] The servo motor drives the driven gear to rotate, thereby driving the spool to move to control the commutation and opening degree adjustment of the three-position four-way directional control valve. The three-position four-way directional control valve controls the moving direction and speed of the lead screw nut by controlling the moving direction and speed of the oil cylinder piston, so as to control the rotating direction and speed of the lead screw output shaft.

[0009] Preferably, the oil cylinder piston is connected with the wear-resistant guide block by screws, and a sealed space is formed between the oil cavity of the second cylinder barrel and the right side of the first cylinder barrel.

[0010] Preferably, a piston sealing ring is arranged between the oil cylinder piston and the inner wall of the oil cavity; a cylinder barrel sealing ring is arranged between the first cylinder barrel and the second cylinder barrel.

[0011] Preferably, a limit block for restricting the maximum left displacement of the wear-resistant guide block is arranged on the left side of the wear-resistant guide rail.

[0012] Preferably, a through hole for the lead screw output shaft to pass through is formed in the front end cover, and the lead screw output shaft is matched with the front end cover through a locking nut.

[0013] Preferably, the turbine is rotatably connected to the rear end cover through a second bearing seat and a second bearing.

[0014] Preferably, the output end of the servo motor is connected with the worm through a coupling.

[0015] Preferably, the connection mode between the wear-resistant guide block and the lead screw nut is welding.

[0016] Preferably, a hollow shaft encoder is installed at one end of the lead screw output shaft extending out of the front end cover, and the hollow shaft encoder is electrically connected with the controller of the servo motor to realize the feedback of the speed regulation of the servo motor.

[0017] Preferably, the front end cover is connected with the first cylinder barrel by screws, the first cylinder barrel is connected with the second cylinder barrel by screws, and the second cylinder barrel is connected with the rear end cover by screws.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The present invention combines a ball screw drive mechanism, a hydraulic cylinder, and a worm and worm gear drive structure, which not only improves the output accuracy but also has a high transmission efficiency, and can achieve fine feed and rapid feed of the swing angle.

[0020] (2) The present invention integrates a hydraulic valve inside the cylinder block. The servo motor can adjust the rotation speed and rotation direction of the output shaft by controlling the opening degree and position of the valve core. Moreover, an encoder is installed at the output end to adjust the input rotation speed of the servo motor, realizing more precise control of the rotation speed at the output end. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 It is a digital swing hydraulic cylinder provided by the present invention;

[0023] Figure 2 It is a schematic diagram of the valve core in different positions provided by the present invention.

[0024] Description of the reference numerals: 1, screw rod output shaft; 2, hollow shaft encoder; 3, front end cover; 4, first bearing seat; 5, limit block; 6, wear-resistant guide rail; 7, wear-resistant guide block; 8, first cylinder barrel; 9, oil cylinder piston; 10, second cylinder barrel; 11, second bearing seat; 12, second bearing; 13, worm; 14, servo motor; 15, third bearing; 16, turbine; 17, driven gear; 18, rear end cover; 19-1, cylinder barrel sealing ring; 19-2, piston sealing ring; 20, three-position four-way directional control valve; 21, screw nut; 22, first bearing; 23, lock nut. Detailed Embodiments

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] As Figure 1 shown, the embodiment of the present invention provides a digital hydraulic swing bar, including a first cylinder barrel 8 provided with a front end cover 3 and a second cylinder barrel 10 provided with a rear end cover 18, and the first cylinder barrel 8 and the second cylinder barrel 10 are fixedly connected;

[0027] The left opening of the first cylinder barrel 8 is rotatably installed with a lead screw output shaft 1 through a first bearing 22 and a first bearing seat 4. The lead screw end of the lead screw output shaft 1 is arranged inside the first cylinder barrel 8 and is fitted with a lead screw nut 21. The outer wall of the lead screw nut 21 is nested and fixedly welded with a wear-resistant guide block 7. The inner wall of the first cylinder barrel 8 is provided with a wear-resistant guide rail 6 that is adapted to the wear-resistant guide block 7 and allows it to slide left and right.

[0028] A servo motor 14 and a rotatable driven gear 17 are provided on the rear end cover 18. The output end of the servo motor 14 is connected with a worm 13. The worm 13 drives a turbine 16 to rotate. The turbine 16 is coaxially connected with the driven gear 17. An oil chamber is opened inside the second cylinder barrel 10, and a three-position four-way directional control valve 20 and a corresponding hydraulic oil circuit communicating with the oil chamber are integrated. An oil cylinder piston 9 is arranged in the oil chamber. The left end of the oil cylinder piston 9 is fixedly connected with the wear-resistant guide block 7. A rack adapted to the driven gear 17 is provided at the end of the spool arranged inside the three-position four-way directional control valve 20.

[0029] The servo motor 14 drives the driven gear 17 to rotate, thereby driving the spool to move to control the commutation and opening degree adjustment of the three-position four-way directional control valve 20. The three-position four-way directional control valve controls the moving direction and speed of the oil cylinder piston 9 to control the moving direction and speed of the lead screw nut 22, and further achieves the control of the rotating direction and speed of the lead screw output shaft 1.

[0030] The oil cylinder piston 9 is connected with the wear-resistant guide block 7 by screws. A sealed space is formed between the oil chamber of the second cylinder barrel 10 and the right side of the first cylinder barrel 8.

[0031] A piston sealing ring 19-2 is arranged between the oil cylinder piston 9 and the inner wall of the oil chamber; a cylinder barrel sealing ring 19-1 is arranged between the first cylinder barrel 8 and the second cylinder barrel 10.

[0032] A limit block 5 for restricting the maximum left displacement of the wear-resistant guide block 7 is arranged on the left side of the wear-resistant guide rail 6.

[0033] A through hole for the lead screw output shaft 1 to pass through is opened on the front end cover 3. The lead screw output shaft 1 is matched with the front end cover through a locking nut 23.

[0034] The turbine 16 is rotatably connected to the rear end cover 18 through a second bearing seat 11 and a second bearing 12.

[0035] The output end of the servo motor 14 is connected with the worm 13 through a third bearing 15.

[0036] One end of the lead screw output shaft 1 extending out of the front end cover 3 is equipped with a hollow shaft encoder 2. The hollow shaft encoder 2 is electrically connected with the controller of the servo motor 14 to realize the feedback for the speed regulation of the servo motor 14.

[0037] The front end cover 3 is connected to the first cylinder barrel 8 by screws. The first cylinder barrel 8 is connected to the second cylinder barrel 10 by screws, and the second cylinder barrel 10 is connected to the rear end cover 18 by screws.

[0038] Working principle: The servo motor 14 drives the worm 13 to rotate. The worm 13 drives the turbine 16 and the driven gear 17 to rotate. The driven gear 17 is adapted to the rack of the spool in the three-position four-way directional control valve 20, thereby driving the spool to move in the valve body, thus changing the flow direction and speed of the hydraulic oil. The flow direction and speed of the hydraulic oil control the moving direction and speed of the oil cylinder piston 9. The moving directions and speeds of the oil cylinder piston 9, the wear-resistant guide block 7, and the lead screw nut 21 are the same. The lead screw nut 21 translates along the wear-resistant guide rail 6 to drive the lead screw output shaft 1 to rotate. The present invention adjusts the flow direction and flow rate of the hydraulic oil by controlling the position and opening degree of the spool, and finally achieves the purpose of controlling the rotation speed of the lead screw output shaft 1.

[0039] As Figure 2 shown, the structural schematic diagram of the directional control valve of the present invention, Figure 2 in (a) is the schematic diagram of the spool shape; when the spool is in the middle position, as Figure 2 shown in (c), the oil inlet P is connected to both the A and B ports. At this time, the pressures on both sides of the oil chamber are the same, and the oil cylinder piston 9 does not move; when the spool is in the right position, as Figure 2 shown in (b), the oil inlet P is connected to the B port, and the oil outlet T is connected to the A port. At this time, the oil cylinder piston 9 moves to the left, and the lead screw output shaft 1 rotates forward; when the spool is in the left position, as Figure 2 shown in (d), the oil inlet P is connected to the A port, and the oil outlet T is connected to the B port. At this time, the oil cylinder piston 9 moves to the right, and the lead screw output shaft 1 rotates reversely. The rotation speed of the lead screw output shaft 1 is controlled by the opening degree of the spool. The larger the opening degree of the spool, the faster the rotation speed of the lead screw output shaft, and the smaller the opening degree of the spool, the slower the rotation speed of the lead screw output shaft.

[0040] The above embodiments are only descriptions of the preferred embodiments of the invention patent, and do not limit the scope of the invention patent. Without departing from the design spirit of the invention patent, various deformations and improvements made by those skilled in the relevant art to the present invention should be included in the protection scope determined by the claims of the present invention.

Claims

1. A digital swing hydraulic cylinder, characterized in that: It comprises a first cylinder barrel (8) provided with a front end cover (3) and a second cylinder barrel (10) provided with a rear end cover (18), wherein the first cylinder barrel (8) and the second cylinder barrel (10) are fixedly connected; The left opening of the first cylinder (8) is rotatably connected to a screw output shaft (1), the screw end of the screw output shaft (1) is arranged inside the first cylinder (8) and is adapted to be equipped with a screw nut (21), a wear-resistant guide block (7) is embedded and fixed on the outer wall of the screw nut (21), and the inner wall of the first cylinder (8) is provided with a wear-resistant guide rail (6) adapted to the wear-resistant guide block (7) and allowing it to slide left and right; The rear end cover (18) is provided with a servo motor (14) and a rotatable driven gear (17); the output end of the servo motor (14) is connected to a worm (13); the worm (13) drives the turbine (16) to rotate; the turbine (16) is coaxially connected to the driven gear (17); an oil chamber is provided inside the second cylinder barrel (10) and a three-position four-way reversing valve (20) and a corresponding hydraulic oil circuit connected to the oil chamber are integrated; an oil cylinder piston (9) is provided in the oil chamber; the left end of the oil cylinder piston (9) is fixedly connected to a wear-resistant guide block (7); a valve core provided in the three-position four-way reversing valve (20) is provided with a rack matched with the driven gear (17) at its end; The servo motor (14) drives the driven gear (17) to rotate, thereby driving the valve core to move to control the switching and opening adjustment of the three-position four-way reversing valve (20). The three-position four-way reversing valve controls the moving direction and speed of the screw nut (22) by controlling the moving direction and speed of the cylinder piston (9), thereby achieving the control of the rotation direction and speed of the screw output shaft (1).

2. A digital swing hydraulic cylinder according to claim 1, characterized in that: The oil cylinder piston (9) is connected to the wear-resistant guide block (7) via screws, and a closed space is formed between the oil chamber of the second cylinder barrel (10) and the right side of the first cylinder barrel (8).

3. A digital swing hydraulic cylinder according to claim 1, characterized in that: A piston sealing ring (19-2) is provided between the oil cylinder piston (9) and the inner wall of the oil chamber; and a cylinder sealing ring (19-1) is provided between the first cylinder barrel (8) and the second cylinder barrel (10).

4. A digital swing hydraulic cylinder according to claim 1, characterized in that: A limit block (5) is provided on the left side of the wear-resistant guide rail (6) for limiting the maximum left displacement of the wear-resistant guide block (7).

5. A digital swing hydraulic cylinder according to claim 1, characterized in that: The front end cover (3) is provided with a through hole for the screw output shaft (1) to pass through, and the screw output shaft (1) is matched with the front end cover via a locking nut (23).

6. A digital swing hydraulic cylinder according to claim 1, characterized in that: The turbine (16) is rotatably connected to the rear end cover (18) via a bearing.

7. A digital swing hydraulic cylinder according to claim 1, characterized in that: The output end of the servo motor (14) is connected to the worm (13) via a coupling.

8. A digital swing hydraulic cylinder according to claim 1, characterized in that: The wear-resistant guide block (7) and the screw nut (19) are connected by welding.

9. A digital swing hydraulic cylinder according to claim 1, characterized in that: One end of the screw output shaft (1) extending out of the front end cover (3) is equipped with a hollow shaft encoder (2), and the hollow shaft encoder (2) is electrically connected to the controller of the servo motor (14) to realize feedback on the speed regulation of the servo motor (14).

10. A digital swing hydraulic cylinder according to claim 1, characterized in that: The front end cover (3) and the first cylinder (8) are connected by screws, the first cylinder (8) and the second cylinder (10) are connected by screws, and the second cylinder (10) and the rear end cover (18) are connected by screws.

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