CN203548409U - Variable cross-section hydraulic cylinder and hydraulic control system thereof - Google Patents

Abstract

A hydraulic cylinder with variable cross-section, including a piston rod, a cylinder barrel and left and right end covers that seal the cylinder barrel, the piston rod includes a main piston rod and a plunger rod, and the main piston rod is sealed and installed on the end cover through the end cover. On the cylinder, the end of the main piston rod is provided with a main piston, and a plurality of the plunger rods are installed on the main piston, and the end of the plunger rod is provided with a secondary piston, and the main piston and the secondary piston are respectively installed in the main piston cavity and the plunger cavity corresponding to the primary piston and the secondary piston in the cylinder. The high-efficiency linear hydraulic cylinder can match the load by selecting the conduction between different small chambers and high-pressure oil circuits and low-pressure oil circuits when performing variable load conditions, and finally achieves the purpose of improving the efficiency of the hydraulic system.

Description

A Variable Cross Section Hydraulic Cylinder and Its Hydraulic Control System

technical field

The utility model relates to a variable section hydraulic cylinder and a hydraulic control system thereof.

Background technique

In recent years, with the rapid development and in-depth cross integration of control technology, perception technology, and new material technology, the performance of walking robots has been continuously improved. The main representatives are: ASIMO, Justin, Packbot, etc. However, because it is mainly driven by the electromechanical system, the load force is small, which restricts the practical process of the robot. The limited load capacity has become one of the "bottleneck" problems restricting the practical application of mobile robots. At present, researchers have begun to try to apply hydraulic systems to mobile robots, the most representative of which are Bigdog, AlphaDog and Cheetah developed by Boston Corporation. This type of robot has a common feature, using a linear hydraulic cylinder as an actuator to drive the movement of each joint. The effective area of the inner cavity of the linear hydraulic cylinder used is fixed and cannot be changed according to the change of the joint load force. When the load becomes smaller, the stable control of the hydraulic cylinder can only be achieved by increasing the pressure loss at the control valve port. However, when the walking robot walks, the load force of each joint varies greatly. During the movement of the robot, there will be a large amount of pressure loss at the valve port, which will eventually lead to a relatively low efficiency of the hydraulic power system. Therefore, it is of great significance to study high-efficiency linear hydraulic cylinders to improve the efficiency of the walking robot's hydraulic system.

Utility model content

The purpose of this utility model is to provide a hydraulic system that can improve the efficiency of variable loads in view of the deficiencies of the prior art. It can realize the matching with the load by selecting the conduction of different small cavities with the high-pressure oil circuit and the low-pressure oil circuit, and finally achieve an improvement. The purpose of the efficiency of the hydraulic system The variable cross-section hydraulic cylinder and its hydraulic control system, the utility model is suitable for working on the equipment where the load changes greatly, and has good economic benefits.

The utility model realizes above-mentioned object through following technical scheme:

A hydraulic cylinder with variable cross-section, including a piston rod, a cylinder barrel and left and right end covers that seal the cylinder barrel, the piston rod includes a main piston rod and a plunger rod, and the main piston rod is sealed and installed on the end cover through the end cover. On the cylinder, the end of the main piston rod is provided with a main piston, and a plurality of the plunger rods are installed on the main piston, and the end of the plunger rod is provided with a secondary piston, and the main piston and the secondary piston are respectively installed in the main piston cavity and the plunger cavity corresponding to the primary piston and the secondary piston in the cylinder.

The plunger rod is connected to the main piston by means of a ball joint.

Four of the plunger rods are installed on the main piston.

A hydraulic control system for a variable cross-section hydraulic cylinder, used to control the variable cross-section hydraulic cylinder, comprising a servo control valve and two-position three-way cartridge valves corresponding to the number of the plunger chambers, the main piston chamber The main piston is divided into a first chamber and a second chamber. The first chamber is provided with a main piston chamber A _e1 port, and the second chamber is provided with a main piston chamber A _e2 port. The P port of the one-position three-way cartridge valve is respectively connected with the A port of the servo control valve and the A _e1 port of the main piston chamber, and the T port of the two-position three-way cartridge valve is respectively connected with the A port of the servo control valve. Port B of the main plunger cavity is connected with the A _e2 port of the main plunger cavity, and the T port of the two-position three-way cartridge valve, the B port of the servo control valve and the A _e2 port of the main plunger cavity are also connected through a one-way The valve is connected to the oil tank, the A port of the two-position three-way cartridge valve communicates with the rodless chamber of the plunger chamber, the P port of the servo control valve communicates with the high-pressure oil port of the pump source, and the servo control valve’s The T port communicates with the fuel tank.

Due to the adoption of the above structure, the active end face of the first chamber in the main piston chamber of the device (that is, the rodless chamber in the usual hydraulic rod) is not a single face, but is divided into five different faces, consisting of four A plunger chamber and the first chamber of the main piston chamber are jointly formed, since the size of the plunger chamber and the area of the secondary piston have been determined when the device is made, the specific output force of each plunger chamber can be determined, and Each plunger chamber is independently controlled by a two-position three-way switch valve. The size of the four plunger chambers can be reasonably designed according to the needs during production. The sizes of the four plunger chambers can be the same or different. There is a load force sensor on it to measure the real-time load force. When performing variable load conditions, the variable-section hydraulic cylinder can select the combination of plunger chambers according to the size of the load, so that the combination of plunger chambers is closest to the actual load. , comprehensively realize the reduction of the high-pressure oil flow supplied by the system to reduce the energy loss caused by the throttling pressure loss at the servo valve, to reduce the oil supply of the system and improve the efficiency of the hydraulic system, while the remaining chambers are conducted through the oil return, At the same time, the oil in the first chamber and the second chamber of the main piston chamber is also used as supplementary oil, thereby reducing the amount of high-pressure oil supply, and finally improving the efficiency of the hydraulic system.

The plunger rod is connected to the main piston by means of a ball joint, which is convenient for processing and assembly.

To sum up, the utility model is a linear hydraulic cylinder that has a certain load matching capability and can improve the efficiency of a variable load hydraulic system. When performing variable load conditions, the matching with the load can be realized by selecting different combinations of plunger chambers and the conduction of the high-pressure oil circuit and the low-pressure oil circuit, and finally achieve the purpose of improving the efficiency of the hydraulic system. The utility model can be used for working in For equipment with large load changes, such as legged robots, exoskeleton equipment, excavators and other equipment, because the variable cross-section hydraulic cylinder has a certain load matching ability and the characteristics of reducing the oil supply of the system, it can improve the efficiency of the hydraulic system. It has good economic benefits.

Description of drawings

Fig. 1 (a) is the perspective view of the utility model;

Fig. 1 (b) is the internal structure figure of the utility model;

Fig. 1 (c) is the exploded structural diagram of the utility model;

Fig. 2 is a sectional view of the utility model;

Fig. 3 is a sectional view of the integrated block of the present utility model;

Fig. 4 is a schematic diagram of the working principle of the utility model;

Fig. 5 is a schematic diagram of the control principle of the utility model;

Fig. 6 is a schematic diagram of the hydraulic cylinder output force of the present utility model;

Fig. 7 is a schematic diagram of the matching between the output force of the hydraulic cylinder and the load of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the specific implementation manner of this patent is described in further detail.

As shown in Figures 1 to 4, the variable cross-section hydraulic cylinder is composed of connecting earrings 1 at both ends, a left end cover 2, a cylinder barrel 3, a right end cover 4, and a piston rod 5. The four two-position three-way cartridge valves 22 on the block (including four two-position three-way cartridge valves in this example) are composed of plugs 23, and the left end cover 2 is connected with the cylinder barrel 31 by screws 24. O-ring 32 is used to realize the sealing between the left end cover 2 and the cylinder barrel 3. In addition to processing the installation hole and the oil inlet and outlet holes required by the two-position three-way cartridge valve 22 on the manifold block 21, four holes are also processed. The plunger chamber includes a first plunger chamber 211, a second plunger chamber 212, a third plunger chamber 213, a fourth plunger chamber 214 and a first column communicating with the corresponding plunger chamber and the two-position three-way cartridge valve 22. The oil inlet hole 215 of the plug chamber, the oil inlet hole 216 of the second plunger chamber, the oil inlet hole 217 of the third plunger chamber and the oil inlet hole 218 of the fourth plunger chamber, the first oil inlet hole 311 is processed on the cylinder barrel 3 (that is, the main piston chamber A _e1 port shown in Figure 1), the second oil inlet hole 312 (that is, the main piston chamber A _e2 port shown in Figure 1) and the corresponding first oil inlet groove 313, the second The second oil inlet groove 314, the piston rod 5 is composed of a main piston rod 51, a main piston 52, four plunger rods 53 and a secondary piston 54, etc., and the four plunger rods 53 are installed on the main piston 52 through a ball hinge, and are passed through the cover. The plate 55 is fixed to prevent the four plunger rods 53 from being separated from the main piston 52, and the right end cover 4 is connected with the cylinder barrel 3 by screws. The plunger chamber, the main piston chamber 315 is divided into a first chamber and a second chamber by the main piston 52 , the first oil inlet groove 313 communicates with the first chamber, and the second oil inlet groove 314 communicates with the second chamber. The variable section hydraulic cylinder control system consists of a variable section hydraulic cylinder, a servo valve 6, a check valve 7 and an oil tank 8, etc.

Working principle of the utility model: as shown in Figure 5, the variable cross-section hydraulic cylinder of the utility model needs to be equipped with a servo control valve 6 to realize high-precision displacement or force servo control, and the P port of the servo control valve 6 is connected with the high-pressure inlet The oil port is connected, the T port of the servo control valve 6 is connected to the low-pressure oil tank, and the two-position three-way cartridge valve 22 is controlled to realize whether the plunger chamber is connected to the main piston chamber A e1 port or is connected to the main piston chamber A _e1 port. The main piston chamber A _e2 port conduction. A load force sensor is arranged on the main piston rod to measure the load on the main piston rod in real time. The cross-sectional size of the plunger chamber can be designed through practical application. By controlling the two-position three-way cartridge valve 22, it can Under the condition of constant oil pressure, an output force with approximately continuous variation within a certain range is obtained. Set the control quantity of the four switching valves as X _k (k=1, 2, 3, 4), when X _k =1, the plunger chamber A _k is connected to the main piston chamber A _e1 port, when X _k =0 , The plunger cavity A _k is connected to the main piston cavity A _e2 port. When the pressure loss of the on-off valve is not considered, the pressure of the chamber A _k is:

P _K =P _e1 x _k +P _e2 (1-x _k )

The output force of the hydraulic cylinder:

When the opening of the servo valve is always left or right, the combination of different on-off valve control values [X ₁ , X ₂ , X ₃ , X ₄ ] can obtain a continuously changing output force of the hydraulic cylinder, as shown in Figure 6 . That is to say, for different loads, the output force of the hydraulic cylinder can be matched with the load of the hydraulic cylinder by controlling the opening and closing of the four switching valves, as shown in Figure 7.

When the main piston rod 51 is stretched out, according to the actual load measured by the load force sensor, the two-position three-way valve 22 is controlled, and the optimum plunger chamber is selected to communicate with the main piston chamber A _e1 port. The combined mode realizes the matching between the output force of the hydraulic cylinder and the actual load force. At the same time, the hydraulic oil in the cavity where the main piston rod 51 is located will flow back into the rest of the plunger cavity. When the cavity where the main piston rod 51 is located When the internal hydraulic oil is not enough to supplement the conducting plunger chamber, oil is replenished through the channel connecting the one-way valve 7 and the oil tank 8, so as to comprehensively reduce the high-pressure oil flow supplied by the system and reduce the throttling at the servo valve Energy loss caused by pressure loss, thereby improving efficiency; when the main piston rod 51 retracts inwardly, according to the actual load situation measured by the load force sensor, the two-position three-way valve 22 is controlled to select the optimal plunger chamber and main piston The combined mode of the conduction of the chamber A _e2 port realizes the matching between the output force of the hydraulic cylinder and the actual load force, and at the same time, the hydraulic oil in the plunger chamber will flow back into the plunger rod chamber that is connected with it, and the reduction system is comprehensively realized. The high-pressure oil flow supplied can reduce the energy loss caused by the throttling pressure loss at the servo valve, thereby improving efficiency.

Claims (4)

1. A variable cross-section hydraulic cylinder, comprising a piston rod, a cylinder barrel and left and right end caps for sealing the cylinder barrel, characterized in that, the piston rod comprises a main piston rod and a plunger rod, and the main piston rod passes through The end cover is sealed and installed on the cylinder, the end of the main piston rod is provided with a main piston, and a plurality of plunger rods are installed on the main piston, and the end of the plunger rod is provided with a secondary The piston, the primary piston and the secondary piston are respectively installed in a primary piston cavity and a plunger cavity corresponding to the primary piston and the secondary piston in the cylinder. 2. The variable cross-section hydraulic cylinder according to claim 1, wherein the plunger rod is connected to the main piston by means of a ball joint. 3. The variable-section hydraulic cylinder according to claim 1 or 2, characterized in that four plunger rods are installed on the main piston. 4. A hydraulic control system for a variable-section hydraulic cylinder, used to control the variable-section hydraulic cylinder according to claims 1 to 3, characterized in that it comprises a servo control valve and two valves corresponding to the number of the plunger chambers. Three-way cartridge valve, the main piston chamber is divided into a first chamber and a second chamber with the main piston as the boundary, the first chamber is provided with a main piston chamber A _e1 port, and the second chamber is A _e2 port of the main piston chamber is provided, and the P port of the two-position three-way cartridge valve is respectively connected with the A port of the servo control valve and the A _e1 port of the main piston chamber, and the two-position three-way plug-in valve The T port of the valve is respectively communicated with the B port of the servo control valve and the A _e2 port of the main plunger cavity, and the T port of the two-position three-way cartridge valve, the B port of the servo control valve and the The A _e2 port of the main plunger chamber is also connected to the oil tank through a one-way valve, the A port of the two-position three-way cartridge valve is connected to the rodless chamber of the plunger chamber, and the P port of the servo control valve is connected to the pump source The high-pressure oil port of the servo control valve communicates with the oil tank.

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