A hydraulic drive system for a chopping device of a silage harvester and its control method

Abstract

The present invention discloses a hydraulic drive system for a chopping device of a silage harvester and a control method thereof. The hydraulic drive oil port of the first plunger motor of the chopping device of the silage harvester is connected to the oil port of the first hydraulic pump. The oil port of the second plunger motor is connected to both the first proportional flow valve and the bypass compensator. The bypass compensator is connected to the inlet of the second check valve, and the outlet of the second check valve is connected to the oil port of the second hydraulic pump. The load sensing signal of the bypass compensator is taken from the load oil source of the cycloid motor. The first proportional flow valve is connected to both the oil port of the first cycloid motor and the outlet of the first check valve. The oil port of the second cycloid motor is connected to the oil port of the second hydraulic pump. The inlet of the first check valve is connected to the oil port of the second hydraulic pump through the second proportional flow valve. The control method includes the harvesting operation of the silage harvester and the maintenance operation of the silage harvester. The present invention can achieve stepless adjustment of the cutting length of the silage harvester, reduce the number of hydraulic pumps, and eliminate the need for excessive manual adjustment.

Description

Technical Field

[0001] The present invention belongs to the technical field of silage harvesters, and particularly relates to a hydraulic drive system for a chopping device of a silage harvester and a control method thereof. Background Art

[0002] With the rapid development of animal husbandry and agricultural and pastoral mechanization, silage harvesters, as agricultural and pastoral machinery and equipment specifically used for harvesting silage feed, have been widely used. This equipment has the advantages of high working efficiency, strong adaptability to various types of silage feed, and the harvested feed can be directly eaten by livestock. It also greatly improves the harvesting efficiency of silage feed and reduces the feeding workload of livestock, playing a positive role in promoting the large-scale operation of animal husbandry. Different cutting lengths have a certain impact on the quality of silage feed, including sensory evaluation, chemical evaluation, and analysis and evaluation of related nutritional indicators after ensiling. Silage harvesters with fixed cutting lengths cannot be adjusted according to different livestock feeding and silage feed types, resulting in poor versatility and adaptability of the silage harvester, unable to guarantee the quality of silage feed, affecting the taste of livestock for silage feed, and further affecting the utilization rate of silage feed during the livestock feeding process, causing unnecessary waste. Summary of the Invention

[0003] The purpose of the present invention is to provide a hydraulic drive system for a chopping device of a silage harvester and a control method thereof to solve the above problems existing in the prior art.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] On the one hand, the present invention provides a hydraulic drive system for a chopping device of a silage harvester, including:

[0006] A bidirectional closed-loop variable displacement piston hydraulic pump for providing a high-pressure oil source as the power oil source, provided with a first hydraulic pump oil port and a second hydraulic pump oil port;

[0007] A fixed displacement piston motor, the output shaft of the fixed displacement piston motor is connected to a cutter roller and can drive the cutter roller to rotate to cut the silage feed, and the first piston motor oil port of the fixed displacement piston motor is communicated with the first hydraulic pump oil port of the bidirectional closed-loop variable displacement piston hydraulic pump;

[0008] A cycloid motor, the output shaft of the cycloid motor is connected to a feeding roller and can drive the feeding roller to act to feed the silage feed to the cutter roller; and

[0009] The control valve group includes a first proportional flow valve, a first check valve, a second proportional flow valve, a bypass compensator and a second check valve. The second plunger motor port of the fixed-displacement plunger motor is connected to both the first proportional flow valve and the bypass compensator. The bypass compensator is connected to the inlet of the second check valve, and the outlet of the second check valve is connected to the second hydraulic pump port of the bidirectional closed-loop variable-displacement plunger hydraulic pump. The load sensing signal of the bypass compensator is taken from the load oil source of the cycloid motor; the first proportional flow valve is connected to both the first cycloid motor port of the cycloid motor and the outlet of the first check valve. The second cycloid motor port of the cycloid motor is connected to the second hydraulic pump port of the bidirectional closed-loop variable-displacement plunger hydraulic pump; the inlet of the first check valve is connected to the second hydraulic pump port of the bidirectional closed-loop variable-displacement plunger hydraulic pump through the second proportional flow valve.

[0010] As a preferred technical solution in the present invention, the control valve group further includes a control valve housing. The first proportional flow valve, the first check valve, the second proportional flow valve, the bypass compensator and the second check valve are all installed on the control valve housing; a first control valve port is provided on the control valve housing, and the first proportional flow valve, the bypass compensator and the second plunger motor port of the fixed-displacement plunger motor are all connected to the first control valve port through pipelines.

[0011] As a preferred technical solution in the present invention, a second control valve port is provided on the control valve housing, and the first proportional flow valve and the first cycloid motor port of the cycloid motor are both connected to the second control valve port through pipelines.

[0012] As a preferred technical solution in the present invention, a third control valve port and a fourth control valve port (F) are provided on the control valve housing. The second cycloid motor port of the cycloid motor is connected to the third control valve port through a pipeline. Both the third control valve port and the outlet of the second check valve are connected to the fourth control valve port through pipelines, and the fourth control valve port is connected to the second hydraulic pump port of the bidirectional closed-loop variable-displacement plunger hydraulic pump through a pipeline.

[0013] As a preferred technical solution in the present invention, the cutter roller is connected to the rotating shaft of the fixed-displacement plunger motor through a gearbox.

[0014] As a preferred technical solution in the present invention, the feeding roller is connected to the rotating shaft of the cycloid motor through a gearbox.

[0015] As a preferred technical solution in the present invention, speed sensors are provided on both the fixed-displacement plunger motor and the cycloid motor.

[0016] On the other hand, the present invention also provides a control method for the hydraulic drive system as described in any one of the above, and the control method is as follows:

[0017] When the silage harvester is harvesting:

[0018] The first hydraulic pump port of the two-way closed-loop variable displacement piston hydraulic pump outputs a high-pressure oil source to the first piston motor port of the fixed displacement piston motor, causing the fixed displacement piston motor to operate and drive the cutter roller to rotate forward to cut the silage feed;

[0019] The second piston motor port of the fixed displacement piston motor outputs a high-pressure oil source to the first proportional flow valve and the bypass compensator. The first proportional flow valve outputs a high-pressure oil source to the first cycloid motor port of the cycloid motor, causing the cycloid motor to operate and drive the feeding roller to feed the silage feed to the cutter roller, and the second cycloid motor port of the cycloid motor transports the high-pressure oil source to the second hydraulic pump port of the two-way closed-loop variable displacement piston hydraulic pump; wherein, the load sensing signal of the bypass compensator is taken from the load oil source of the cycloid motor, and the excess high-pressure oil source is transported to the second hydraulic pump port of the two-way closed-loop variable displacement piston hydraulic pump through the second one-way valve;

[0020] When the silage harvester is under maintenance:

[0021] The second hydraulic pump port of the two-way closed-loop variable displacement piston hydraulic pump outputs a high-pressure oil source to the high-pressure oil source to the second proportional flow valve and the second cycloid motor port of the cycloid motor. Through the flow splitting of the second proportional flow valve, the cycloid motor starts to rotate reversely at a low speed. The high-pressure oil source output by the second proportional flow valve through the first one-way valve and the high-pressure oil source output by the cycloid motor from the first cycloid motor port are jointly input into the first proportional flow valve, and the high-pressure oil source output by the first proportional flow valve is transported to the fixed displacement piston motor for the fixed displacement piston motor to rotate reversely at a low speed.

[0022] As a preferred technical solution in the present invention, the first proportional flow valve is connected with a controller. When the silage harvester is performing harvesting operations, the controller outputs a current signal to the first proportional flow valve to adjust the cutting length L of the silage feed by controlling the rotational speed n1 of the cycloid motor. Among them, the cutting length L and the rotational speed n1 of the cycloid motor satisfy the following formula:

[0023] L=(n1·D1·π) / (n2·N),

[0024] In the formula, L is the length of the cut silage feed; n1 is the rotational speed of the cycloid motor; D1 is the diameter of the feeding roller; n2 is the rotational speed of the fixed displacement piston motor; N is the number of blades evenly distributed around the cutter roller in one revolution.

[0025] As a preferred technical solution in the present invention, when the cutter roller is connected to the rotating shaft of the fixed displacement piston motor through a gearbox, and the feeding roller is connected to the rotating shaft of the cycloid motor through a gearbox, the cutting length L and the rotational speed n1 of the cycloid motor satisfy the following formula:

[0026] L=(n1·D1·π·i1) / (n2·N·i2),

[0027] Wherein, i1 is the speed ratio of the gearbox between the cycloidal motor and the feeding roller; i2 is the speed ratio of the gearbox between the metering piston motor and the cutter roller.

[0028] Beneficial effects: During the harvesting operation of the forage harvester, the two-way closed-loop variable displacement piston hydraulic pump inputs a high-pressure oil source to the metering piston motor through the first hydraulic pump oil port, prompting the metering piston motor to start operating. Moreover, by giving different current signals to the first proportional flow valve, the opening degree of the first proportional flow valve is adjusted, which cooperates with the high-pressure oil source output from the first hydraulic pump oil port, making the cutting of the silage by the cutter roller flexibly adjustable, and thus realizing the stepless adjustment of the cutting length of the forage harvester; then the first proportional flow valve conveys a high-pressure oil source to the cycloidal motor to ensure the normal operation of the cycloidal motor, and the rotation speed of the cycloidal motor can be controlled by the size of the high-pressure oil source output from the first proportional flow valve to the cycloidal motor. The second cycloidal motor oil port of the cycloidal motor is connected to the second hydraulic pump oil port of the two-way closed-loop variable displacement piston hydraulic pump. When the cycloidal motor rotates forward, the second cycloidal motor oil port of the cycloidal motor serves as the output oil port, and the output high-pressure oil source is conveyed back to the two-way closed-loop variable displacement piston hydraulic pump. Among them, the load sensing signal of the bypass compensator is taken from the load oil source of the cycloidal motor. When the cycloidal motor rotates forward, the opening degree of the bypass compensator can be adjusted according to the load oil source situation of the cycloidal motor, so that the excess high-pressure oil source can flow through the bypass compensator and the second one-way valve to the second hydraulic pump oil port of the two-way closed-loop variable displacement piston hydraulic pump in sequence, ensuring the stable rotation speed of the cycloidal motor; when the forage harvester is under maintenance, the feeding roller and the cutter roller need to rotate slowly in reverse. At this time, the second hydraulic pump oil port of the two-way closed-loop variable displacement piston hydraulic pump can output a high-pressure oil source to the high-pressure oil source to the second proportional flow valve and the second cycloidal motor oil port of the cycloidal motor. Through the shunt of the second proportional flow valve, the cycloidal motor starts to rotate slowly in reverse. The high-pressure oil source output by the second proportional flow valve through the first one-way valve and the high-pressure oil source output from the first cycloidal motor oil port of the cycloidal motor are jointly input to the first proportional flow valve, and the high-pressure oil source output by the first proportional flow valve is conveyed to the metering piston motor for the metering piston motor to rotate slowly in reverse. The present invention uses hydraulic transmission, can realize the stepless adjustment of the cutting length of the forage harvester, and thus enables the forage harvester to be adjusted according to different feeding livestock and types of silage, making the versatility and adaptability of the forage harvester better, being able to ensure the quality of the silage, not affecting the taste of the silage for livestock, and thus not affecting the utilization rate of the silage during the livestock feeding process, avoiding unnecessary waste; the present invention uses one two-way closed-loop variable displacement piston hydraulic pump to drive the metering piston motor and the cycloidal motor to work, reducing the number of hydraulic pumps and also reducing the equipment cost. Moreover, many devices in the present invention are electronic devices that are convenient to be controlled by an electric control program and do not require too much manual adjustment. Description of the Drawings

[0029] Figure 1This is the schematic diagram of the hydraulic drive system in the present invention;

[0030] Figure 2 This is the axonometric view of the control valve group in the present invention.

[0031] In the figure: 1 - bidirectional closed-loop variable piston hydraulic pump; 2 - fixed-displacement piston motor; 3 - cycloidal motor; 4 - first proportional flow valve; 5 - first check valve; 6 - second proportional flow valve; 7 - second check valve; 8 - bypass compensator; 9 - control valve group; A - first hydraulic pump oil port; B - second hydraulic pump oil port; C - first control valve oil port; D - second control valve oil port; E - third control valve oil port; F - fourth control valve oil port. Detailed implementation manners

[0032] 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 present invention in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the drawings is only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation to the present invention.

[0033] Embodiment:

[0034] As Figure 1 and Figure 2 shown, this embodiment provides a hydraulic drive system for a chopping device of a forage harvester, including:

[0035] A bidirectional closed-loop variable piston hydraulic pump 1, used to provide a high-pressure oil source as the power oil source, is provided with a first hydraulic pump oil port A and a second hydraulic pump oil port B. Both the first hydraulic pump oil port A and the second hydraulic pump oil port B can be used as the oil outlet and the oil return port, and can be adjusted according to the actual situation without limitation;

[0036] A fixed-displacement piston motor 2, the output shaft of the fixed-displacement piston motor 2 is connected to a cutter roller and can drive the cutter roller to rotate to cut the forage. The first piston motor oil port of the fixed-displacement piston motor 2 is communicated with the first hydraulic pump oil port A of the bidirectional closed-loop variable piston hydraulic pump 1. The bidirectional closed-loop variable piston hydraulic pump 1 inputs a high-pressure oil source to the fixed-displacement piston motor 2 through the first hydraulic pump oil port A to drive the fixed-displacement piston motor 2 to work;

[0037] A cycloidal motor 3, the output shaft of the cycloidal motor 3 is connected to a feeding roller and can drive the feeding roller to act to feed the forage to the cutter roller, and then it is convenient for the cutter roller connected to the fixed-displacement piston motor 2 to cut the forage; and

[0038] The control valve group 9 includes a first proportional flow valve 4, a first check valve 5, a second proportional flow valve 6, a bypass compensator 7 and a second check valve 8. The second plunger motor oil port of the fixed-displacement plunger motor 2 is communicated with both the first proportional flow valve 4 and the bypass compensator 7. When the silage harvester is harvesting, the first plunger motor oil port of the fixed-displacement plunger motor 2 serves as the oil source inlet, and the second plunger motor oil port serves as the oil source outlet. Through the circulation of the high-pressure oil source in the fixed-displacement plunger motor 2, the fixed-displacement plunger motor 2 is prompted to start operating. Moreover, by giving different current signals to the first proportional flow valve 4, the opening degree of the first proportional flow valve 4 is adjusted to cooperate with the high-pressure oil source output from the oil port A of the first hydraulic pump. The bypass compensator 7 is connected to the inlet of the second check valve 8, and the outlet of the second check valve 8 is connected to the second hydraulic pump oil port B of the bidirectional closed-loop variable-displacement plunger hydraulic pump 1. The load sensing signal of the bypass compensator 7 is taken from the load oil source of the cycloid motor 3. When the cycloid motor 3 is rotating forward, the opening degree of the bypass compensator 7 can be adjusted according to the load oil source situation of the cycloid motor 3, so that the excess high-pressure oil source can flow through the bypass compensator 7 and the second check valve 8 to the second hydraulic pump oil port B of the bidirectional closed-loop variable-displacement plunger hydraulic pump 1 in sequence, ensuring the stable rotation speed of the cycloid motor 3. When the cycloid motor 3 is operating, the first proportional flow valve 4 is communicated with the first cycloid motor oil port of the cycloid motor 3 and the outlet of the first check valve 5. The first proportional flow valve 4 supplies the high-pressure oil source to the cycloid motor 3 to ensure the normal operation of the cycloid motor 3, and the rotation speed of the cycloid motor 3 can be controlled by the size of the high-pressure oil source output from the first proportional flow valve 4 to the cycloid motor 3. The second cycloid motor oil port of the cycloid motor 3 is connected to the second hydraulic pump oil port B of the bidirectional closed-loop variable-displacement plunger hydraulic pump 1. When the cycloid motor 3 is rotating forward, the second cycloid motor oil port of the cycloid motor 3 serves as the output oil port to deliver the output high-pressure oil source back to the bidirectional closed-loop variable-displacement plunger hydraulic pump 1. The inlet of the first check valve 5 is connected to the second hydraulic pump oil port B of the bidirectional closed-loop variable-displacement plunger hydraulic pump 1 through the second proportional flow valve 6. When the silage harvester is harvesting, the first check valve 5 and the second proportional flow valve 6 are not used as spares. When the silage harvester is being repaired, the feeding roller and the cutting knife roller need to rotate slowly in reverse. At this time, the second hydraulic pump oil port B of the bidirectional closed-loop variable-displacement plunger hydraulic pump 1 can output a high-pressure oil source to the high-pressure oil source to the second proportional flow valve 6 and the second cycloid motor oil port of the cycloid motor 3. Through the flow splitting of the second proportional flow valve 6, the cycloid motor 3 starts to rotate slowly in reverse. The high-pressure oil source output by the second proportional flow valve 6 through the first check valve 5 and the high-pressure oil source output from the first cycloid motor oil port of the cycloid motor 3 are jointly input into the first proportional flow valve 4. The high-pressure oil source output by the first proportional flow valve 4 is delivered to the fixed-displacement plunger motor 2 for the fixed-displacement plunger motor 2 to rotate slowly in reverse.

[0039] During the harvesting operation of the silage harvester, the bidirectional closed-loop variable displacement piston hydraulic pump 1 inputs a high-pressure oil source to the fixed displacement piston motor 2 through the first hydraulic pump oil port A, prompting the fixed displacement piston motor 2 to start running. By giving different current signals to the first proportional flow valve 4, the opening degree of the first proportional flow valve 4 is adjusted, which cooperates with the high-pressure oil source output from the first hydraulic pump oil port A, enabling the cutting roller to adjust the cutting of the silage feed flexibly, and thus achieving stepless adjustment of the cutting length of the silage harvester. Then, the first proportional flow valve 4 conveys a high-pressure oil source to the cycloid motor 3 to ensure the normal operation of the cycloid motor 3. Moreover, the rotation speed of the cycloid motor 3 can be controlled by the size of the high-pressure oil source output from the first proportional flow valve 4 to the cycloid motor 3. The second cycloid motor oil port of the cycloid motor 3 is connected to the second hydraulic pump oil port B of the bidirectional closed-loop variable displacement piston hydraulic pump 1. When the cycloid motor 3 rotates forward, the second cycloid motor oil port of the cycloid motor 3 serves as the output oil port, and the output high-pressure oil source is conveyed back to the bidirectional closed-loop variable displacement piston hydraulic pump 1. Among them, the load sensing signal of the bypass compensator 7 is taken from the load oil source of the cycloid motor 3. When the cycloid motor 3 rotates forward, the opening degree of the bypass compensator 7 can be adjusted according to the load oil source situation of the cycloid motor 3, so that the excess high-pressure oil source can flow through the bypass compensator 7 and the second one-way valve 8 to the second hydraulic pump oil port B of the bidirectional closed-loop variable displacement piston hydraulic pump 1 in sequence, ensuring the stable rotation speed of the cycloid motor 3. When the silage harvester is under maintenance, the feeding roller and the cutting roller need to rotate reversely at a low speed. At this time, the second hydraulic pump oil port B of the bidirectional closed-loop variable displacement piston hydraulic pump 1 can output a high-pressure oil source to the high-pressure oil source to the second proportional flow valve 6 and the second cycloid motor oil port of the cycloid motor 3. Through the flow splitting of the second proportional flow valve 6, the cycloid motor 3 starts to rotate reversely at a low speed. The high-pressure oil source output by the second proportional flow valve 6 through the first one-way valve 5 and the high-pressure oil source output from the first cycloid motor oil port of the cycloid motor 3 are jointly input into the first proportional flow valve 4, and the high-pressure oil source output by the first proportional flow valve 4 is conveyed to the fixed displacement piston motor 2 for the fixed displacement piston motor 2 to rotate reversely at a low speed. The present invention uses hydraulic transmission, which can achieve stepless adjustment of the cutting length of the silage harvester, and then enables the silage harvester to be adjusted according to different feeding livestock and types of silage feed, making the universality and adaptability of the silage harvester better, being able to ensure the quality of the silage feed, not affecting the taste of the silage feed for livestock, and thus not affecting the utilization rate of the silage feed during the livestock feeding process, avoiding unnecessary waste. The present invention uses a bidirectional closed-loop variable displacement piston hydraulic pump 1 to drive the fixed displacement piston motor 2 and the cycloid motor 3 to work, reducing the number of hydraulic pumps and also lowering the equipment cost. Moreover, many devices in the present invention are electronic devices that are convenient to be controlled by an electric control program, without excessive manual adjustment.

[0040] As a preferred implementation in this embodiment, it should be further noted that the control valve group 9 further includes a control valve housing, and the first proportional flow valve 4, the first check valve 5, the second proportional flow valve 6, the bypass compensator 7, and the second check valve 8 are all installed on the control valve housing. As Figure 2 shown, integrating the control valve group 9 on one housing can achieve the pre-assembly production of the equipment, making the whole more compact and the subsequent installation easier; a first control valve oil port C is provided on the control valve housing, and the second plunger motor oil port of the first proportional flow valve 4, the bypass compensator 7, and the fixed-displacement plunger motor 2 are all connected to the first control valve oil port C through pipelines, so that the high-pressure oil source output from the second plunger motor oil port of the fixed-displacement plunger motor 2 can circulate normally within the control valve group 9 to adjust the fixed-displacement plunger motor 2 and the cycloid motor 3 through the control valve group 9.

[0041] As a preferred implementation in this embodiment, it should be further noted that a second control valve oil port D is provided on the control valve housing, and the first proportional flow valve 4 and the first cycloid motor oil port of the cycloid motor 3 are both connected to the second control valve oil port D through pipelines, which can make the connection between the first cycloid motor oil port of the cycloid motor 3 and the first proportional flow valve 4 more convenient.

[0042] As a preferred implementation in this embodiment, it should be further noted that a third control valve oil port E and a fourth control valve oil port F are provided on the control valve housing, the second cycloid motor oil port of the cycloid motor 3 is connected to the third control valve oil port E through a pipeline, the third control valve oil port E and the outlet of the second check valve 8 are both connected to the fourth control valve oil port F through pipelines, the fourth control valve oil port F is connected to the second hydraulic pump oil port B of the bidirectional closed-loop variable-displacement plunger hydraulic pump 1 through a pipeline, and the third control valve oil port E and the fourth control valve oil port F are provided with separate pipelines within the control valve housing, which also facilitates the connection of the first check valve 5 and the second proportional flow valve 6, so that the series-connected first check valve 5 and the second proportional flow valve 6 are in parallel with the cycloid motor 3 and can be used as a bypass of the cycloid motor 3 during reverse rotation to reduce the rotation speed of the cycloid motor 3 during reverse rotation.

[0043] As a preferred implementation in this embodiment, it should be further noted that the cutter roller is connected to the rotating shaft of the fixed-displacement plunger motor 2 through a gearbox, and thus the rotation speed of the cutter roller is controlled within a specified range.

[0044] As a preferred implementation in this embodiment, it should be further noted that the feeding roller is connected to the rotating shaft of the cycloid motor 3 through a gearbox, and thus the speed of the feeding roller is controlled within a specified range.

[0045] As a preferred embodiment in this implementation, it should be further noted that speed sensors are provided on both the fixed-displacement piston motor 2 and the cycloid motor 3. The fixed-displacement piston motor 2 and the cycloid motor 3 are internally integrated with speed sensors, which avoids the influence of the harsh working environment of agricultural machinery on the reliability of the speed sensors and reduces the failure rate.

[0046] A control method for a hydraulic drive system as described in any one of the above, the control method is as follows:

[0047] When the forage harvester is harvesting:

[0048] The first hydraulic pump port A of the bidirectional closed-loop variable piston hydraulic pump 1 outputs a high-pressure oil source to the first piston motor port of the fixed-displacement piston motor 2, so that the fixed-displacement piston motor 2 works and drives the cutter roller to rotate forward to cut the silage;

[0049] The second piston motor port of the fixed-displacement piston motor 2 outputs a high-pressure oil source to the first proportional flow valve 4 and the bypass compensator 7. The first proportional flow valve 4 outputs a high-pressure oil source to the first cycloid motor port of the cycloid motor 3, so that the cycloid motor 3 works and drives the feeding roller to send the silage to the cutter roller, and the second cycloid motor port of the cycloid motor 3 transports the high-pressure oil source to the second hydraulic pump port B of the bidirectional closed-loop variable piston hydraulic pump 1; among them, the load sensing signal of the bypass compensator 7 is taken from the load oil source of the cycloid motor 3, and the excess high-pressure oil source is transported to the second hydraulic pump port B of the bidirectional closed-loop variable piston hydraulic pump 1 through the second one-way valve 8; using hydraulic transmission, the stepless adjustment of the cutting length of the forage harvester can be realized, so that the forage harvester can be adjusted according to different feeding livestock and types of silage, making the versatility and adaptability of the forage harvester better, ensuring the quality of the silage, not affecting the taste of the silage for livestock, and thus not affecting the utilization rate of the silage during the livestock feeding process, avoiding unnecessary waste. Using one bidirectional closed-loop variable piston hydraulic pump 1 to drive the fixed-displacement piston motor 2 and the cycloid motor 3 to work reduces the number of hydraulic pumps and also reduces the equipment cost. Moreover, many devices in the present invention are electronic devices that are convenient to be controlled by an electric control program and do not require too much manual adjustment.

[0050] When the forage harvester is being repaired:

[0051] The second hydraulic pump oil port B of the bidirectional closed variable plunger hydraulic pump 1 outputs a high-pressure oil source to the second proportional flow valve 6 and the second cycloid motor oil port of the cycloid motor 3. Through the flow division of the second proportional flow valve 6, the cycloid motor 3 starts to rotate reversely at a low speed. The high-pressure oil source output by the second proportional flow valve 6 through the first one-way valve 5 and the high-pressure oil source output by the cycloid motor 3 from the first cycloid motor oil port are jointly input into the first proportional flow valve 4. The high-pressure oil source output by the first proportional flow valve 4 is delivered to the fixed-displacement plunger motor 2 for the fixed-displacement plunger motor 2 to rotate reversely at a low speed, ensuring that the equipment can be repaired normally and smoothly.

[0052] As a preferred implementation in this embodiment, it should be further noted that the first proportional flow valve 4 is connected to a controller. When the silage harvester is harvesting, the controller outputs a current signal to the first proportional flow valve 4 to adjust the cutting length L of the silage by controlling the rotational speed n1 of the cycloid motor 3. Among them, the cutting length L and the rotational speed n1 of the cycloid motor 3 satisfy the following formula:

[0053] L = (n1·D1·π) / (n2·N),

[0054] In the formula, L is the length of the silage cut segment; n1 is the rotational speed of the cycloid motor 3; D1 is the diameter of the feed roller; n2 is the rotational speed of the fixed-displacement plunger motor 2; N is the number of blades evenly distributed around the cutting knife roller in one week. The cutting length L can be determined in advance, and then the rotational speed of the cycloid motor 3, the diameter of the feed roller, the rotational speed of the fixed-displacement plunger motor 2, and the number of blades evenly distributed around the cutting knife roller in one week are controlled to meet the requirements of the cutting length L, making the cutting length L accurately controllable.

[0055] As a preferred implementation in this embodiment, it should be further noted that when the cutting knife roller is connected to the rotating shaft of the fixed-displacement plunger motor 2 through a gearbox, and the feed roller is connected to the rotating shaft of the cycloid motor 3 through a gearbox, the cutting length L and the rotational speed n1 of the cycloid motor 3 satisfy the following formula:

[0056] L = (n1·D1·π·i1) / (n2·N·i2),

[0057] In the formula, i1 is the speed ratio of the gearbox between the cycloid motor 3 and the feed roller; i2 is the speed ratio of the gearbox between the fixed-displacement plunger motor 2 and the cutting knife roller. Whether a gearbox is installed between the rotating shaft of the fixed-displacement plunger motor 2 and the cutting knife roller, or a gearbox is installed between the rotating shaft of the cycloid motor 3 and the feed roller, the cutting length L can be accurately controllable.

[0058] It should be noted that in practice, because speed sensors are installed on both the fixed-displacement plunger motor 2 and the cycloid motor 3, the rotational speed of the cycloid motor 3 and the rotational speed of the fixed-displacement plunger motor 2 can also be known, thereby making the cutting length L more accurately controllable.

[0059] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydraulic drive system for a chopping device of a silage harvester, characterized in that, Comprising: A two-way closed-loop variable displacement piston hydraulic pump (1) for providing a high-pressure oil source as a power oil source, provided with a first hydraulic pump oil port (A) and a second hydraulic pump oil port (B); A fixed displacement piston motor (2), the output shaft of the fixed displacement piston motor (2) is connected with a cutter roller and can drive the cutter roller to rotate to cut the silage, and the first piston motor oil port of the fixed displacement piston motor (2) is communicated with the first hydraulic pump oil port (A) of the two-way closed-loop variable displacement piston hydraulic pump (1); A cycloid motor (3), the output shaft of the cycloid motor (3) is connected with a feeding roller and can drive the feeding roller to act to feed the silage to the cutter roller; and A control valve group (9), including a first proportional flow valve (4), a first check valve (5), a second proportional flow valve (6), a bypass compensator (7) and a second check valve (8), the second piston motor oil port of the fixed displacement piston motor (2) is communicated with both the first proportional flow valve (4) and the bypass compensator (7), the bypass compensator (7) is connected with the inlet of the second check valve (8), the outlet of the second check valve (8) is connected with the second hydraulic pump oil port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1), and the load sensing signal of the bypass compensator (7) is taken from the load oil source of the cycloid motor (3); the first proportional flow valve (4) is communicated with both the first cycloid motor oil port of the cycloid motor (3) and the outlet of the first check valve (5), and the second cycloid motor oil port of the cycloid motor (3) is connected with the second hydraulic pump oil port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1); the inlet of the first check valve (5) is connected with the second hydraulic pump oil port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1) through the second proportional flow valve (6).

2. The hydraulic drive system of a silage cutter device according to claim 1, characterized in that, The control valve group (9) further includes a control valve housing, the first proportional flow valve (4), the first check valve (5), the second proportional flow valve (6), the bypass compensator (7) and the second check valve (8) are all installed on the control valve housing; a first control valve oil port (C) is arranged on the control valve housing, and the first proportional flow valve (4), the bypass compensator (7) and the second piston motor oil port of the fixed displacement piston motor (2) are all communicated with the first control valve oil port (C) through pipelines.

3. The hydraulic drive system of a silage chopping device according to claim 2, characterized in that, A second control valve oil port (D) is arranged on the control valve housing, and the first proportional flow valve (4) and the first cycloid motor oil port of the cycloid motor (3) are all communicated with the second control valve oil port (D) through pipelines.

4. The hydraulic drive system of a silage cutter device according to claim 2, characterized in that, A third control valve oil port (E) and a fourth control valve oil port (F) are arranged on the control valve housing, the second cycloid motor oil port of the cycloid motor (3) is communicated with the third control valve oil port (E) through a pipeline, the third control valve oil port (E) and the outlet of the second check valve (8) are both communicated with the fourth control valve oil port (F) through pipelines, and the fourth control valve oil port (F) is communicated with the second hydraulic pump oil port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1) through a pipeline.

5. The hydraulic drive system of a silage chopping device according to claim 1, characterized in that, The cutter roller is connected with the rotating shaft of the fixed displacement piston motor (2) through a gearbox.

6. The hydraulic drive system of a silage chopping device according to claim 1, characterized in that, The feeding roller is connected with the rotating shaft of the cycloid motor (3) through a gearbox.

7. The hydraulic drive system of a forage harvester chopping device according to claim 1, characterized in that, Speed sensors are arranged on both the fixed displacement piston motor (2) and the cycloid motor (3).

8. A control method for a hydraulic drive system according to any one of claims 1-7, characterized in that, The control method is as follows: When the silage harvester is in harvesting operation: The first hydraulic pump port (A) of the two-way closed-loop variable displacement piston hydraulic pump (1) outputs a high-pressure oil source to the first piston motor port of the fixed displacement piston motor (2), causing the fixed displacement piston motor (2) to operate and drive the cutter roller to rotate forward to cut the silage; The second piston motor port of the fixed displacement piston motor (2) outputs a high-pressure oil source to the first proportional flow valve (4) and the bypass compensator (7). The first proportional flow valve (4) outputs a high-pressure oil source to the first cycloid motor port of the cycloid motor (3), causing the cycloid motor (3) to operate and drive the feeding roller to feed the silage to the cutter roller, and the second cycloid motor port of the cycloid motor (3) transports the high-pressure oil source to the second hydraulic pump port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1); wherein, the load sensing signal of the bypass compensator (7) is taken from the load oil source of the cycloid motor (3), and the excess high-pressure oil source is transported to the second hydraulic pump port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1) through the second check valve (8); When the silage harvester is under maintenance: The second hydraulic pump port (B) of the two-way closed-loop variable displacement piston hydraulic pump (1) outputs a high-pressure oil source to the high-pressure oil source to the second proportional flow valve (6) and the second cycloid motor port of the cycloid motor (3). Through the flow splitting of the second proportional flow valve (6), the cycloid motor (3) starts to rotate reversely at a low speed. The high-pressure oil source output by the second proportional flow valve (6) through the first check valve (5) and the high-pressure oil source output by the cycloid motor (3) from the first cycloid motor port are jointly input to the first proportional flow valve (4), and the high-pressure oil source output by the first proportional flow valve (4) is transported to the fixed displacement piston motor (2) for the fixed displacement piston motor (2) to rotate reversely at a low speed.

9. The control method of the hydraulic drive system according to claim 8, characterized in that, The first proportional flow valve (4) is connected to a controller. When the silage harvester is in harvesting operation, the controller outputs a current signal to the first proportional flow valve (4) to adjust the cutting length L of the silage by controlling the rotational speed n1 of the cycloid motor (3). Among them, the cutting length L and the rotational speed n1 of the cycloid motor (3) satisfy the following formula: L = (n1·D1·π) / (n2·N), In the formula, L is the length of the cut silage; n1 is the rotational speed of the cycloid motor (3); D1 is the diameter of the feeding roller; n2 is the rotational speed of the fixed displacement piston motor (2); N is the number of blades evenly distributed in one circumference of the cutter roller.

10. The control method of the hydraulic drive system according to claim 9, characterized in that, When the cutter roller is connected to the rotating shaft of the fixed displacement piston motor (2) through a gearbox, and the feeding roller is connected to the rotating shaft of the cycloid motor (3) through a gearbox, the cutting length L and the rotational speed n1 of the cycloid motor (3) satisfy the following formula: L = (n1·D1·π·i1) / (n2·N·i2), In the formula, i1 is the speed ratio of the gearbox between the cycloid motor (3) and the feeding roller; i2 is the speed ratio of the gearbox between the fixed displacement piston motor (2) and the cutter roller.

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