Proportional servo device of oil cylinder

Abstract

The utility model relates to an oil cylinder proportional servo device, and relates to the field of hydraulic devices, the oil cylinder proportional servo device comprises a main oil cylinder and a reversing valve, and further comprises a control oil cylinder and a servo oil cylinder, the control oil cylinder is connected with the servo oil cylinder through a connecting oil pipe, so that the control oil cylinder and the servo oil cylinder move synchronously, and the control oil cylinder is connected with the reversing valve. The reversing valve is connected with the two sides of a piston of the main oil cylinder through a first main oil pipe and a second main oil pipe respectively, a cylinder body of the servo oil cylinder is connected with the reversing valve so that the reversing valve can be driven to reverse, a piston rod of the servo oil cylinder is connected with a piston rod of the main oil cylinder through a synchronous assembly, and the synchronous assembly is connected with the servo oil cylinder. And the piston rod of the main oil cylinder and the piston rod of the servo oil cylinder extend out in equal proportion. The opening degree of the reversing valve can be adjusted in time according to the stretching-out condition of the main oil cylinder, the main oil cylinder and the control oil cylinder stretch out in equal proportion, and therefore the stretching-out control precision of the piston rod of the main oil cylinder is improved.

Description

Technical Field

[0001] This application relates to the field of hydraulic devices, and particularly to a proportional servo device for an oil cylinder. Background Art

[0002] The main function of an oil cylinder in a hydraulic system is to convert hydraulic energy into mechanical energy to achieve linear reciprocating motion or swinging motion. Due to the simple structure, reliable operation, and ability to achieve smooth motion of the oil cylinder, it is widely used in the hydraulic systems of various machinery, such as construction machinery, industrial machinery, agricultural machinery, medical machinery, and ships.

[0003] The existing oil cylinder device mainly consists of a main oil cylinder, a directional control valve, a pump station, etc. The directional control valve is used to control the change of the flow direction of hydraulic oil between the pump station and the main oil cylinder, and the extension and retraction of the piston rod of the main oil cylinder are controlled by changing the opening degree of the directional control valve. However, there is an obvious lag in controlling the extension of the piston rod of the main oil cylinder by controlling the opening degree of the directional control valve, resulting in low control accuracy of the extension of the piston rod of the main oil cylinder. Utility Model Content

[0004] In order to improve the problem of low control accuracy of the extension of the piston rod of the main oil cylinder caused by controlling the extension and retraction of the piston rod of the main oil cylinder by changing the opening degree of the directional control valve, this application provides a proportional servo device for an oil cylinder.

[0005] The proportional servo device for an oil cylinder provided by this application adopts the following technical solutions:

[0006] A proportional servo device for an oil cylinder includes a main oil cylinder and a directional control valve, and also includes a control oil cylinder and a servo oil cylinder. The control oil cylinder and the servo oil cylinder are connected by a connecting oil pipe so that the control oil cylinder and the servo oil cylinder move synchronously. The directional control valve is respectively connected to both sides of the piston of the main oil cylinder through a first main oil pipe and a second main oil pipe. The cylinder body of the servo oil cylinder is connected to the directional control valve to be able to drive the directional control valve to change its direction. The piston rod of the servo oil cylinder is connected to the piston rod of the main oil cylinder through a synchronization component so that the extension speeds of the piston rod of the main oil cylinder and the piston rod of the servo oil cylinder change proportionally.

[0007] By adopting the above technical solution, when driving the main oil cylinder, the control oil cylinder controls the synchronous movement of the servo oil cylinder. Since the piston rod of the servo oil cylinder is connected to the piston rod of the main oil cylinder through a synchronization component, the cylinder body of the servo oil cylinder pushes the directional valve to change its direction, causing the hydraulic oil to enter the main oil cylinder from the first main oil pipe and driving the piston rod of the main oil cylinder to extend. When the piston rod of the main oil cylinder extends slowly, the extending speed of the piston rod of the servo oil cylinder affected by the main oil cylinder through the synchronization component is less than the extending speed of the piston rod of the control oil cylinder. At this time, the cylinder body of the servo oil cylinder drives the opening of the directional valve to increase, and the extending speed of the piston rod of the main oil cylinder accelerates, driving the extending speed of the piston rod of the servo oil cylinder to accelerate until it synchronizes with the extending speed of the piston rod of the control oil cylinder, making the extending of the piston rod of the main oil cylinder and the piston rod of the control oil cylinder change proportionally. When the piston rod of the main oil cylinder extends quickly, the extending speed of the piston rod of the servo oil cylinder affected by the main oil cylinder through the synchronization component is greater than the extending speed of the piston rod of the control oil cylinder. At this time, the cylinder body of the servo oil cylinder drives the opening of the directional valve to decrease, and the extending speed of the piston rod of the main oil cylinder decreases, driving the extending speed of the piston rod of the servo oil cylinder to decrease until it synchronizes with the extending speed of the piston rod of the control oil cylinder, making the extending of the piston rod of the main oil cylinder and the piston rod of the control oil cylinder change proportionally. The piston rod of the main oil cylinder is fed back to the directional valve through the synchronization component and the servo oil cylinder, so that the opening of the directional valve can be adjusted in time according to the extending condition of the main oil cylinder, making the main oil cylinder and the control oil cylinder extend proportionally, thereby improving the control accuracy of the extension of the piston rod of the main oil cylinder.

[0008] In a specific feasible embodiment, the synchronization component includes a speed-changing part. The extending speed of the piston rod of the main oil cylinder is V, the speed-changing ratio of the speed-changing part is N (N < 1), and the moving speed of the piston rod of the servo oil cylinder is NV.

[0009] By adopting the above technical solution, by varying the speed between the piston rod of the main oil cylinder and the piston rod of the servo oil cylinder through the speed-changing part, the moving range of the piston rod of the main oil cylinder can be increased, and at the same time, the size of the servo oil cylinder can be reduced.

[0010] In a specific feasible embodiment, the speed-changing part includes a servo rack, a driving rack, and a gear speed-changing mechanism. The servo rack is fixedly arranged on the piston rod of the servo oil cylinder, the driving rack is fixedly arranged on the piston rod of the main oil cylinder, and both the servo rack and the driving rack are engaged with the gear in the gear speed-changing mechanism, so that the ratio of the moving speed of the driving rack to the moving speed of the servo rack is N.

[0011] By adopting the above technical solution, when the piston rod of the servo oil cylinder moves, the hydraulic oil enters the cylinder body of the main oil cylinder, and the servo rack controls the proportional movement of the driving rack through the gear speed-changing mechanism, making the piston rod of the main oil cylinder and the piston rod of the servo oil cylinder move proportionally.

[0012] In a specific feasible implementation, the gear shifting mechanism includes a first gear and a second gear. The first gear and the second gear are coaxially and fixedly arranged through a gear shaft. The radius ratio of the second gear to the first gear is N. The first gear meshes with the driving rack, and the second gear meshes with the servo rack.

[0013] By adopting the above technical solution, the servo rack controls the driving rack through the first gear and the second gear, and at the same time, through the radius ratio of the first gear and the second gear, controls the piston rod of the main oil cylinder to move proportionally. The structure is simple and the control accuracy is high.

[0014] In a specific feasible implementation, the gear shifting mechanism is a P-level speed change, including an input gear, an output gear, and M gear shifting gear sets, and P>1, M = P - 1. The input gear and the output gear are both rotatably arranged on the frame body through a rotating shaft. The diameter ratio of the output gear to the input gear is X. The input gear meshes with the driving rack, and the output gear meshes with the servo rack. The two rotating shafts are connected through M gear shifting gear sets. The transmission ratios of each gear shifting gear set are Z1, Z2...Z M , and X*(Z1*Z2*...*Z M ) = N.

[0015] By adopting the above technical solution, the servo rack performs multi-level speed change control on the driving rack through the input gear, the output gear, and M reduction gear sets, improves the speed change range between the main oil cylinder and the servo oil cylinder, increases the moving range of the piston rod of the main oil cylinder, and improves the applicable range of the main oil cylinder.

[0016] In a specific feasible implementation, the directional control valve is connected to the power pumping station through an oil inlet pipe and an oil return pipe. The oil inlet pipe and the oil return pipe are communicated through a connecting pipe. A safety valve is provided on the connecting pipe.

[0017] By adopting the above technical solution, when the main oil cylinder is subjected to a large external force, the safety valve opens, the main oil cylinder slowly retracts, and at the same time, through the gear-rack speed change device, drives the servo rack and the servo oil cylinder to forcibly retract. This action is simultaneously feedback to the control oil cylinder, causing the control oil cylinder to retract, improving the safety of the main oil cylinder during operation.

[0018] In a specific feasible implementation, the connecting oil pipe includes a first oil pipe and a second oil pipe arranged crosswise. The two ends of the first oil pipe and the second oil pipe are respectively connected to both sides of the pistons of the control oil cylinder and the servo oil cylinder. The first oil pipe and the second oil pipe are communicated through an adjusting pipe. A stop valve is provided on the adjusting pipe.

[0019] By adopting the above technical solution, when the work is completed, the cut-off valve is opened, and the first oil pipe is communicated with the second oil pipe, so that the oil pressures on both sides of the piston of the servo oil cylinder and on both sides of the piston of the control oil cylinder are the same, which is convenient for the synchronous adjustment of the control oil cylinder and the servo oil cylinder.

[0020] In a specific feasible implementation, the first oil pipe and the second oil pipe are communicated through a first supplementary oil pipe, the first supplementary oil pipe and the inlet oil pipe are communicated through a second supplementary oil pipe, and one-way valves are arranged on both sides of the second supplementary oil pipe of the first supplementary oil pipe.

[0021] By adopting the above technical solution, the inlet oil pipe replenishes hydraulic oil into the control oil cylinder and the servo oil cylinder through the first supplementary oil pipe and the second supplementary oil pipe, ensuring sufficient hydraulic oil in the control oil cylinder and the servo oil cylinder, and making the synchronization of the control oil cylinder and the servo oil cylinder better; the one-way valve can prevent the communication between the first oil pipe and the second oil pipe.

[0022] In summary, the present application includes at least one of the following beneficial technical effects:

[0023] 1. The piston rod of the main oil cylinder is fed back to the reversing valve through the synchronous component and the servo oil cylinder, so that the opening of the reversing valve can be adjusted in time according to the extension condition of the main oil cylinder, so that the main oil cylinder and the control oil cylinder extend in equal proportion, thereby improving the control accuracy of the extension of the piston rod of the main oil cylinder;

[0024] 2. By arranging multiple groups between the servo rack and the driving rack, the speed change range between the main oil cylinder and the servo oil cylinder is increased, the stroke of the piston rod of the main oil cylinder is increased, and the applicable range of the main oil cylinder is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of an oil cylinder proportional servo device according to Embodiment 1 of the present application.

[0026] Figure 2 is a structural sectional view for showing the servo device.

[0027] Figure 3 is a sectional view for showing the mating relationship between the first gear and the second gear.

[0028] Figure 4 is a schematic structural diagram of an oil cylinder proportional servo device according to Embodiment 2 of the present application.

[0029] Description of reference numerals: 1. Frame; 2. Main oil cylinder; 3. Directional control valve; 4. Control oil cylinder; 5. Servo oil cylinder; 6. Power pumping station; 71. First main oil pipe; 72. Second main oil pipe; 73. Connecting oil pipe; 731. First oil pipe; 732. Second oil pipe; 741. Inlet oil pipe; 742. Return oil pipe; 8. Synchronization component; 81. Variable speed component; 82. Servo rack; 83. Driving rack; 84. Gear transmission mechanism; 841. First gear; 842. Second gear; 843. Input gear; 844. Output gear; 845. Variable speed gear set; 8451. Large gear; 8452. Small gear; 91. Safety valve; 92. Adjusting pipe; 93. Stop valve; 94. First supplementary oil pipe; 95. Second supplementary oil pipe; 96. Check valve; 97. Connecting pipe. Detailed implementation mode

[0030] The following further elaborates on this application in conjunction with the attached Figures 1-4 drawings.

[0031] The embodiment of this application discloses an oil cylinder proportional servo device.

[0032] Embodiment 1

[0033] Referring to Figure 1 , an oil cylinder proportional servo device includes a main oil cylinder 2, a directional control valve 3, a control oil cylinder 4, and a servo oil cylinder 5. The directional control valve 3 is a reciprocating spool valve. The directional control valve 3 is connected to the power pumping station 6 through the inlet oil pipe 741 and the return oil pipe 742, and is communicated with the inner cavities on both sides of the piston of the main oil cylinder 2 through the first main oil pipe 71 and the second main oil pipe 72. The directional control valve 3 has three states, namely, the disconnected state, the reversing state, and the forward state. When the directional control valve 3 is in the disconnected state, both the inlet oil pipe 741 and the return oil pipe 742 are disconnected from the first main oil pipe 71 and the second main oil pipe 72; when the directional control valve 3 is in the reversing state, the inlet oil pipe 741 is communicated with the second main oil pipe 72, and the return oil pipe 742 is communicated with the first main oil pipe 71, so that the piston rod of the main oil cylinder 2 contracts; when the directional control valve 3 is in the forward state, the inlet oil pipe 741 is communicated with the first main oil pipe 71, and the return oil pipe 742 is communicated with the second main oil pipe 72, so that the piston rod of the main oil cylinder 2 extends outwards.

[0034] Referring to Figure 1, the control oil cylinder 4 and the servo oil cylinder 5 are connected and arranged through a connecting oil pipe 73. The connecting oil pipe 73 includes a first oil pipe 731 and a second oil pipe 732 which are cross - arranged. The first oil pipe 731 and the second oil pipe 732 are respectively located at both ends of the control oil cylinder 4 and the servo oil cylinder 5. When the piston of the control oil cylinder 4 slides, the piston in the servo oil cylinder 5 slides in the same direction and synchronously. The cylinder body of the servo oil cylinder 5 is slidably connected to the frame 1 and fixedly connected to the valve core of the reversing valve 3, driving the valve core of the reversing valve 3 to slide, so as to realize the adjustment of the flow direction and opening degree of the reversing valve 3. The piston rod of the servo oil cylinder 5 is connected to the piston rod of the main oil cylinder 2 through a synchronization component 8, so that the piston rods of the main oil cylinder 2 and the servo oil cylinder 5 can extend synchronously and proportionally. This device can be applied to the loading and unloading robotic arms on ships. Multiple such devices are used on the power pumping station 6 to realize the driving and control of each joint of the robotic arm.

[0035] Refer to Figure 2 、 Figure 3 , in this embodiment, the synchronization component 8 includes a speed - changing part 81. The speed - changing ratio of the speed - changing part 81 is N. Let the extending speed of the piston rod of the main oil cylinder 2 be V, then the extending speed of the piston rod of the servo oil cylinder 5 is NV. In this embodiment, N < 1 is selected as an example, and the piston rod of the main oil cylinder 2 to the piston rod of the servo oil cylinder 5 makes a decelerating motion. The speed - changing part 81 in this embodiment includes a servo rack 82, a driving rack 83, and a gear speed - changing mechanism 84. The servo rack 82 is fixedly arranged on the piston rod of the servo oil cylinder 5 along the sliding direction of the servo oil cylinder 5. The driving rack 83 is fixedly arranged on the piston rod of the main oil cylinder 2 along the sliding direction parallel to the piston rod of the main oil cylinder 2. The gear speed - changing mechanism 84 in this embodiment includes a first gear 841 and a second gear 842. The first gear 841 and the second gear 842 are coaxially and fixedly arranged through a gear shaft. The gear shaft is inserted into the frame 1 and rotatably connected. The ratio of the radius of the second gear 842 to the first gear 841 is N. The first gear 841 meshes with the driving rack 83, and the second gear 842 meshes with the servo rack 82, so that the ratio of the extending speeds of the servo rack 82 and the driving rack 83 is N.

[0036] Refer to Figure 1 , in the power pumping station 6, a connecting pipe 97 is connected and arranged between the inlet oil pipe 741 and the return oil pipe 742. A safety valve 91 is connected in series on the connecting pipe 97. When the main oil cylinder 2 is subjected to a large external force, the safety valve 91 opens, and the main oil cylinder 2 slowly retracts. At the same time, through the gear - rack speed - changing device, the servo rack 82 and the servo oil cylinder 5 are forcibly retracted. This action is simultaneously fed back to the control oil cylinder 4, causing the control oil cylinder 4 to retract, improving the safety of the main oil cylinder 2 during operation.

[0037] Refer to Figure 1, as there is a slight oil leakage in the oil cylinder during use, it will cause the piston positions in the control oil cylinder 4 and the servo oil cylinder 5 to be misaligned. To solve this problem, the first oil pipe 731 and the second oil pipe 732 are connected through the adjustment pipe 92, and a stop valve 93 is arranged in parallel on the adjustment pipe 92 to control the opening and closing of the adjustment pipe 92. After the work is completed, the stop valve 93 is opened, and the first oil pipe 731 and the second oil pipe 732 are connected, so that the oil pressures on both sides of the piston of the servo oil cylinder 5 and both sides of the piston of the control oil cylinder 4 are the same, pushing the piston rod in the control oil cylinder 4 to move, so that the piston in the control oil cylinder 4 moves to the corresponding position of the piston in the servo oil cylinder 5, facilitating the synchronous adjustment of the control oil cylinder 4 and the servo oil cylinder 5.

[0038] Refer to Figure 1 , to solve the problem that the hydraulic oil in the cylinder body decreases due to oil leakage in the oil cylinder, a first oil replenishing pipe 94 is arranged between the first oil pipe 731 and the second oil pipe 732. The first oil replenishing pipe 94 is respectively connected to the first oil pipe 731 and the second oil pipe 732. A second oil replenishing pipe 95 is connected to the first oil replenishing pipe 94, and the second oil replenishing pipe 95 is connected to the oil inlet pipe 741 in the power pumping station 6. The hydraulic oil in the oil inlet pipe 741 enters the control oil cylinder 4 and the servo oil cylinder 5 through the second oil replenishing pipe 95, the first oil replenishing pipe 94, the first oil pipe 731, and the second oil pipe 732 to supplement the hydraulic oil in the cylinder body to ensure that the hydraulic oil in the cylinder body is sufficient and improve the synchronism of the piston rod movement of the servo oil cylinder 5 and the control oil cylinder 4. When replenishing oil, in order to prevent the hydraulic oil in the cylinder body from flowing back into the second oil replenishing pipe 95, two one-way valves 96 are arranged in series on the first oil replenishing pipe 94, and the one-way valves 96 are located on both sides of the second oil replenishing pipe 95, so as to ensure that the hydraulic oil in the second oil replenishing pipe 95 can only flow into the first oil pipe 731 and the second oil pipe 732 unidirectionally, ensuring the stability of the hydraulic oil in the oil cylinder.

[0039] The implementation principle of Embodiment 1 is as follows: When driving the main cylinder 2, the control cylinder 4 controls the synchronous movement of the servo cylinder 5. Since the piston rod of the servo cylinder 5 is connected to the piston rod of the main cylinder 2 through the servo rack 82, the second gear 842, the first gear 841, and the driving rack 83, the cylinder block of the servo cylinder 5 pushes the reversing valve 3 from the off state to the forward state, so that the hydraulic oil enters the main cylinder 2 from the first main oil pipe 71, driving the piston rod of the main cylinder 2 to extend; when the piston rod of the main cylinder 2 extends slowly, the main cylinder 2 drives the first gear 841 to rotate through the driving rack 83, the first gear 841 drives the second gear 842 to rotate, and the second gear 842 drives the servo rack 82 to rotate. The extending speed of the piston rod of the servo cylinder 5 is less than the extending speed of the piston rod of the control cylinder 4. At this time, the cylinder block of the servo cylinder 5 drives the opening of the reversing valve 3 to increase, and the extending speed of the piston rod of the main cylinder 2 speeds up, driving the extending speed of the piston rod of the servo cylinder 5 to speed up until it synchronizes with the extending speed of the piston rod of the control cylinder 4, so that the extending of the piston rod of the main cylinder 2 and the piston rod of the control cylinder 4 changes proportionally; when the piston rod of the main cylinder 2 extends quickly, the extending speed of the piston rod of the servo cylinder 5 driven by the main cylinder 2 is greater than the extending speed of the piston rod of the control cylinder 4. At this time, the cylinder block of the servo cylinder 5 drives the opening of the reversing valve 3 to decrease, and the extending speed of the piston rod of the main cylinder 2 decreases, driving the extending speed of the piston rod of the servo cylinder 5 to decrease until it synchronizes with the extending speed of the piston rod of the control cylinder 4, so that the extending of the piston rod of the main cylinder 2 and the piston rod of the control cylinder 4 changes proportionally. The piston rod of the main cylinder 2 is fed back to the reversing valve 3 through the synchronization assembly 8 and the servo cylinder 5, so that the opening of the reversing valve 3 can be adjusted in time according to the extending condition of the main cylinder 2, so that the main cylinder 2 and the control cylinder 4 extend proportionally, thereby improving the control accuracy of the extension of the piston rod of the main cylinder 2.

[0040] Embodiment 2

[0041] Refer to Figure 4, the difference between this embodiment and Embodiment 1 is that the gear transmission mechanism 84 in this embodiment is a P-level speed change. Taking P = 2 as an example, the gear transmission mechanism 84 in this embodiment includes an input gear 843, an output gear 844, and M speed change gear sets 845. M = P - 1, so M = 1. The input gear 843 and the output gear 844 are both rotatably arranged on the frame 1 through rotating shafts. The diameter ratio of the output gear 844 to the input gear 843 is X, and X < 1. The speed change gear set 845 includes a large gear 8451 and a small gear 8452. The small gear 8452 is coaxially and fixedly arranged on the rotating shaft where the input gear 843 is located. The large gear 8451 is coaxially and fixedly arranged on the rotating shaft where the output gear 844 is located. The large gear 8451 and the small gear 8452 are meshed and driven. The transmission ratio between the large gear 8451 and the small gear 8452 is Z1, and X * Z1 = N. The output gear 844 is meshed with the servo rack 82, and the input gear 843 is meshed with the driving rack 83. When P > 2, the deceleration setting method of the speed change gear set 845 is the same as that of the deceleration gear set in the reduction gearbox to obtain a greater deceleration effect.

[0042] The implementation principle of Embodiment 2 is that the servo rack 82 performs multi-stage speed change control on the driving rack 83 through the input gear 843, the output gear 844, and a deceleration gear set, which can reduce the value range of N, increase the speed change range between the main oil cylinder 2 and the servo oil cylinder 5, increase the moving range of the piston rod of the main oil cylinder 2, and improve the applicable range of the main oil cylinder 2.

[0043] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A cylinder proportional servo device, comprising a master cylinder (2) and a reversing valve (3), characterized in that: It also includes a control cylinder (4) and a servo cylinder (5), wherein the control cylinder (4) and the servo cylinder (5) are connected via a connecting oil pipe (73) so that the control cylinder (4) and the servo cylinder (5) move synchronously, the reversing valve (3) is connected to the two sides of the piston of the master cylinder (2) via a first main oil pipe (71) and a second main oil pipe (72) respectively, the cylinder body of the servo cylinder (5) is connected to the reversing valve (3) so as to be able to drive the reversing valve (3) to switch, and the piston rod of the servo cylinder (5) and the piston rod of the master cylinder (2) are connected via a synchronizing assembly (8) so that the piston rod of the master cylinder (2) and the piston rod of the servo cylinder (5) extend in equal proportion; The synchronization component (8) comprises a transmission component (81), the extension speed of the piston rod of the master cylinder (2) is V, the speed ratio of the transmission component (81) is N, and the moving speed of the piston rod of the servo cylinder (5) is NV.

2. The cylinder proportional servo device according to claim 1, characterized in that: The speed change component (81) comprises a servo rack (82), an active rack (83), and a gear speed change mechanism (84); the servo rack (82) is fixedly arranged on the piston rod of the servo oil cylinder (5); the active rack (83) is fixedly arranged on the piston rod of the main oil cylinder (2); the servo rack (82) and the active rack (83) are both meshed with the gears in the gear speed change mechanism (84), so that the ratio of the moving speed of the active rack (83) to the moving speed of the servo rack (82) is N.

3. The cylinder proportional servo device according to claim 2, characterized in that: The gear speed change mechanism (84) comprises a first gear (841) and a second gear (842); the first gear (841) and the second gear (842) are coaxially fixed via a gear shaft; the radius ratio of the second gear (842) to the first gear (841) is N; the first gear (841) is meshed with the active rack (83); and the second gear (842) is meshed with the servo rack (82).

4. The oil cylinder proportional servo device according to claim 2, characterized in that: The gear speed change mechanism (84) is a P-level speed change, comprising an input gear (843), an output gear (844), and M speed change gear sets (845), wherein P>1, M=P-1, the input gear (843) and the output gear (844) are both rotatably arranged with the frame (1) via a rotating shaft, the diameter ratio of the input gear (843) and the output gear (844) is X, the input gear (843) is meshed with the active rack (83), the output gear (844) is meshed with the servo rack (82), the two rotating shafts are connected via the M speed change gear sets (845), and the transmission ratios of each speed change gear set (845) are respectively Z1, Z2, ..., Z M , and X*(Z1*Z2*……*Z M )=N.

5. The cylinder proportional servo device according to claim 1, characterized in that: The reversing valve (3) is connected to the power pump station (6) via an oil inlet pipe (741) and an oil return pipe (742); the oil inlet pipe (741) and the oil return pipe (742) are connected via a connecting pipe (97); and a safety valve (91) is provided on the connecting pipe (97).

6. The oil cylinder proportional servo device according to claim 5, characterized in that: The connecting oil pipe (73) comprises a first oil pipe (731) and a second oil pipe (732) which are arranged crosswise, and the two ends of the first oil pipe (731) and the second oil pipe (732) are respectively connected to the two sides of the piston of the control oil cylinder (4) and the servo oil cylinder (5), and the first oil pipe (731) and the second oil pipe (732) are connected through a regulating pipe (92), and a stop valve (93) is provided on the regulating pipe (92).

7. The oil cylinder proportional servo device according to claim 6, characterized in that: The first oil pipe (731) and the second oil pipe (732) are connected via a first oil replenishment pipe (94), and the first oil replenishment pipe (94) and the oil inlet pipe (741) are connected via a second oil replenishment pipe (95). The first oil replenishment pipe (94) is provided with a one-way valve (96) on both sides of the second oil replenishment pipe (95).

Images