CN203239674U - Servo hydraulic cylinder - Google Patents

Abstract

The utility model discloses a servo hydraulic cylinder, which comprises a cylinder, the cylinder is provided with a piston driven by a servo motor through a transmission mechanism, and the side walls of both ends of the cylinder are respectively provided with an oil inlet and a cylinder. The oil return port is characterized in that the tail of the piston is provided with an axial center hole, the tail end of the piston is provided with a small hole I which is symmetrical to the center hole, and the side wall of the middle part of the piston is provided with The small hole II, which is symmetrical to the central hole and communicates with the oil return port, has a spiral groove on the inner wall surface of the tail of the cylinder, and the small hole I communicates with the central hole and the spiral groove. The small hole I and the spiral groove constitute a variable resistance half-bridge. Simple structure, easy installation, good anti-pollution performance, small rotation angle, continuous control, fast response, good speed stability and high control precision, etc., can be widely used in various manipulators, robots, metallurgical equipment, machine tools, engineering machinery, etc. in automation equipment.

Description

Servo hydraulic cylinder

technical field

The utility model relates to a servo hydraulic cylinder, in particular to a helical servo hydraulic cylinder with double degrees of freedom.

Background technique

As a typical electro-hydraulic integrated control component, servo hydraulic cylinder is widely used in various automation equipment such as manipulators, robots, metallurgical equipment, machine tools, and engineering machinery. The traditional servo hydraulic cylinder is composed of a stepping motor, a hydraulic slide valve, a hydraulic cylinder and a mechanical feedback mechanism. The pulse control signal is input through the stepping motor, and the displacement of the piston is fed back through its internal ball screw. The steering and rotation angle of the stepping motor The displacement is combined corresponding to the direction of movement of the piston. This kind of servo hydraulic cylinder has complex structure, high cost of ball screw, high precision requirement of servo valve, and has disadvantages such as discrete step, slow response speed, low precision, poor pollution resistance, and high price.

Utility model content

The technical problem to be solved by the utility model is to provide a servo hydraulic cylinder with simple structure, convenient installation and high precision.

The technical scheme adopted by the utility model to solve the above-mentioned technical problems is: a servo hydraulic cylinder, including a cylinder barrel, the cylinder barrel is provided with a piston driven by a servo motor through a transmission mechanism, and the two ends of the cylinder barrel are The wall is respectively provided with an oil inlet and an oil return port. It is characterized in that the tail of the piston is provided with an axial center hole, and the tail end of the piston is opened with a small hole I that is symmetrical to the center hole. The side wall of the middle part of the piston is provided with a small hole II which is symmetrical to the central hole and communicated with the oil return port. The inner wall surface of the tail of the cylinder is provided with a spiral groove. The small hole I and the The central hole communicates with the spiral groove, and the small hole I and the spiral groove form a variable resistance half-bridge.

The head of the piston is also equipped with a grating ruler and a photoelectric encoder, which can detect the axial and rotational signals of the piston, and transmit this signal to the control module for comparison with the digital pulse signal sent out, thus forming a closed-loop structure Feedback can compensate for factors such as system temperature, pressure load, internal leakage and dead zone.

The transmission mechanism includes a pinion connected to the output shaft of the servo motor, a large gear that is sleeved on the head of the piston and meshed with the small gear, and the two sides of the large gear are respectively provided with the The piston is fixed on the upper pressing plate and the lower pressing plate, and the upper pressing plate and the lower pressing plate clamp the large gear, and the rotation of the servo motor is transmitted through the small gear and the large gear, thereby driving the piston to rotate.

Compared with the prior art, the utility model has the advantages of simple structure, convenient installation, good anti-pollution performance, small rotation angle, continuous control, fast response, good speed stability and high control precision, and can be widely used in In various manipulators, robots, metallurgical equipment, machine tools, construction machinery and other automation equipment; the double-degree-of-freedom screw mechanism is adopted, that is, the piston has a degree of freedom of rotation around the axis and a degree of freedom of movement along the axis, avoiding the sealing when the piston rotates , while ensuring the accurate transmission of rotational motion.

Description of drawings

Fig. 1 is the front view of hydraulic cylinder of the present utility model;

Fig. 2 is a sectional view taken along line A-A of Fig. 1 .

Detailed ways

The utility model is described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1 and Fig. 2, a servo hydraulic cylinder is applied to an electro-hydraulic servo control system or a proportional servo control system, including a cylinder 1, a piston 2 is arranged inside the cylinder 1, and the piston 2 extends out of the head of the cylinder 1 , the tail end of the piston 2 is fixed to the flange 3 located at the tail end of the cylinder 1, the flange 3 is fixed to the cylinder 1 by screws 31, and the part of the flange 3 extending into the cylinder 1 is between the cylinder 1 Equipped with O-ring I32 to prevent leakage of hydraulic oil.

The head of the cylinder 1 is fixed with an upper cylinder cover 4, which plays the role of fixing, sealing and guiding the cylinder 1. The servo motor 5 is fixed to the upper cylinder head 4, and a gasket 52 is arranged at the joint, which drives the piston 2 to rotate through the transmission mechanism. An O-shaped sealing ring II11 and an O-shaped sealing ring are respectively arranged between the upper cylinder head 4, the cylinder barrel 1, and the piston 2. Circle III12. The transmission mechanism includes a pinion 51 connected to the output shaft of the servo motor 5, a bull gear 22 that is sheathed on the head of the piston 2 out of the cylinder 1 and meshed with the pinion 51, and the two sides of the bull gear 22 are respectively provided with pistons. 2 fixed upper pressing plate 23 and lower pressing plate 24, locking the upper pressing plate 23 and lower pressing plate 24 with fastening screws can clamp the large gear 22, so that the rotation of the large gear 22 can drive the upper pressing plate 23 and the lower pressing plate 24, that is Rotation of piston 2.

The head of the piston 2 is also provided with a grating ruler 27 and a photoelectric encoder (not shown), the grating ruler 27 is used to detect the axial displacement of the piston 2, and the photoelectric encoder is used to detect the rotation angle of the piston 2.

The tail of the piston 2 is provided with an axial cylindrical center hole 25, and the tail end of the piston 2 is provided with two small holes I 29 that are symmetrical to the center hole 25. There are two symmetrical small holes II 26 , and a triangular spiral groove 28 is opened on the inner wall surface of the tail of the cylinder 1 , and the small hole I 29 communicates with the central hole 25 and the spiral groove 28 . The side wall of the tail of the cylinder 1 is provided with an arcuate oil inlet 13, which communicates with the piston 2, and the side wall of the head of the cylinder 1 is provided with an arcuate oil return port 14, which is communicated with the small hole II26.

When working, the control module of the servo control system sends a digital pulse signal to the servo motor 5, the servo motor 5 works through the transmission mechanism to make the piston 2 rotate, the overlapping area between the small hole I29 and the spiral groove 28 decreases, and the high pressure oil flows from the inlet The oil port 13 enters the high-pressure chamber of the piston 2 (as seen from Figure 2, it is the small chamber at the right end of the piston 2), and enters the working chamber of the piston 2 through the triangular spiral groove 28 and the small hole I29 opened on the inner wall surface of the cylinder 1 (from Figure 2 shows the large cavity at the left end of the piston 2), and then passes through the small hole I29, the center hole 25 and the small hole 26 to leave the cylinder 1 from the oil return port 14, and the pressure in the working chamber increases during this process , breaking the original balance relationship, the piston 2 moves to the right, which gradually increases the area of the overlapping part between the small hole I29 and the spiral groove 28 until it returns to the original value, and the pressure in the working chamber also decreases to the original value. The balance value is equal to the downward thrust of the high pressure chamber and the external load, and the piston 2 reaches a balanced relationship again, and vice versa. In this way, the helical groove 28 and the small hole I29 form a variable resistance half-bridge, so that the area of the overlapping part between the small hole I29 and the helical groove 28 changes, thereby changing the pressure in the working chamber. When the servo motor 5 inputs a certain rotation angle, the piston 2 will produce a corresponding displacement.

At the same time, the grating ruler 27 and the photoelectric encoder can detect the axial and rotational signals of the piston 2, and transmit the signals to the control module for comparison with the digital pulse signals sent out, thereby forming a closed-loop structure feedback, which can control the system Compensate for factors such as temperature, pressure load, internal leakage and dead zone.

The above description is only a preferred embodiment of the present utility model. It should be pointed out that for those skilled in the art, various deformations and improvements can be made without departing from the principle of the present utility model. It is regarded as the protection scope of the present utility model.

Claims (3)

1. servo hydraulic cylinder, comprise cylinder barrel (1), be provided with the piston (2) that is driven by driving mechanism by actuating motor (5) in the described cylinder barrel (1), offer respectively filler opening (13) and return opening (14) on the two end part sidewall of described cylinder barrel (1), it is characterized in that, be provided with axial center hole (25) in the afterbody of described piston (2), the tail end of described piston (2) has relative center hole (25) and is symmetrical aperture I (29), offer relatively described center hole (25) on the sidewall at described piston (2) middle part and be the symmetrical aperture II (26) that is communicated with described return opening (14), offer spiral chute (28) on the interior side-wall surface of described cylinder barrel (1) afterbody, described aperture I (29) is communicated with center hole (25) and spiral chute (28), and described aperture I (29) consists of the adjustable resistance half-bridge with spiral chute (28).

2. servo hydraulic cylinder as claimed in claim 1 is characterized in that, the head of described piston (2) also is provided with grating scale (27) and photoelectric encoder.

3. servo hydraulic cylinder as claimed in claim 1 or 2, it is characterized in that, described driving mechanism comprises the small gear (51) that is connected with the output shaft of described actuating motor (5), that be set in described piston (2) head and gearwheel (22) described small gear (51) engagement, the both sides of described gearwheel (22) are respectively equipped with top board (23) and the press table (24) fixing with described piston (2), and described top board (23) and press table (24) clamp described gearwheel (22).

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