A gear interlock system and method for electro-hydraulic shifting of a tractor transmission

Abstract

The present invention discloses a gear interlock system and method for electro-hydraulic shifting of a tractor transmission. By means of the on-off of a two-position three-way directional control valve, the on-off of a three-position four-way manual control mechanical valve, and the on-off of a three-position four-way directional control valve, the interlock function between gears at this time and the precise control of the gear shifting operation function are realized. The present invention can achieve the interlock control of the gear position by the gear shifting mechanism under the condition of frequent gear shifting and shifting operations, thereby reducing the wear of the gear shifting mechanism and improving the safety of the driver during operation.

Description

Technical Field

[0001] The present invention belongs to the field of agricultural machinery and is a safety control system for shift interlock operation. Background Art

[0002] Tractors are one of the most common engineering vehicles in agricultural machinery and are widely used in agricultural engineering. With the development of agricultural modernization, tractors play an increasingly important role in the actual application of agriculture. Therefore, the requirements for the working life and maintenance of tractors are gradually increasing. Among them, the interlock function during the shift operation of tractors is not yet perfect, mainly manifested in that during the shift process of tractors, interference may occur between gears, resulting in wear of the shift gears, shortening the working life, and even causing gear shifting errors, affecting the operation safety of tractors and posing potential safety hazards. Summary of the Invention

[0003] In order to avoid the above problems, the present invention proposes a gear interlock system and method for electro-hydraulic shifting of a tractor transmission, aiming to change the hydraulic oil circuit route, realize the interlock function between gears during frequent gear shifting and shifting operations of the tractor, prevent movement interference, thereby reducing the wear of the gear shifting mechanism and ensuring driving safety.

[0004] The present invention adopts the following technical solutions to solve the technical problems:

[0005] A gear interlock system for electro-hydraulic shifting of a tractor transmission according to the present invention is characterized by comprising: an oil tank, an oil pump, a two-position three-way directional control valve, a 1 / 2 gear oil circuit check valve, a 3 / 4 gear oil circuit check valve, a 1 / 2 gear manual control valve, a 3 / 4 gear manual control valve, a 1 / 2 gear three-position four-way directional control valve, a 3 / 4 gear three-position four-way directional control valve, a first gear solenoid valve, a second gear solenoid valve, a third gear solenoid valve, a fourth gear solenoid valve, a 1 / 2 gear shift cylinder, and a 3 / 4 gear shift cylinder;

[0006] The oil tank supplies oil to the 1 / 2 gear shift cylinder and the 3 / 4 gear shift cylinder through the oil pump respectively;

[0007] When the two-position three-way directional control valve is in the left position, its lower oil chamber is connected to the oil outlet of the oil pump, the upper right oil chamber of the two-position three-way directional control valve is connected to the inlet of the 1 / 2 gear oil circuit check valve, and the upper left oil chamber of the two-position three-way directional control valve is connected to the oil tank;

[0008] When the two-position three-way directional control valve is in the right position, its lower oil chamber is connected to the oil outlet of the oil pump, the upper left oil chamber of the two-position three-way directional control valve is connected to the inlet of the 3 / 4 gear oil circuit check valve, and the upper right oil chamber of the two-position three-way directional control valve is connected to the oil tank;

[0009] When the 1 / 2 gear manual control mechanical valve is in the left or right position under the control of the shift fork, its oil chambers are both in the cut-off state;

[0010] When the 1 / 2 gear manual control mechanical valve is in the middle position under the control of the shift fork, the upper left oil chamber of the 1 / 2 gear manual control mechanical valve is connected to the lower left oil chamber of the 1 / 2 gear three-position four-way directional control valve, the upper right oil chamber of the 1 / 2 gear manual control mechanical valve is respectively connected to the lower right oil chamber of the 1 / 2 gear three-position four-way directional control valve and the lower left oil chamber of the 3 / 4 gear manual control mechanical valve, the lower left oil chamber of the 1 / 2 gear manual control mechanical valve is communicated with the fuel tank, and the lower right oil chamber of the 1 / 2 gear manual control mechanical valve is connected to the oil outlet of the 1 / 2 gear oil circuit check valve;

[0011] The upper left oil chamber of the 1 / 2 gear three-position four-way directional control valve is communicated with the lower oil chamber of the first gear solenoid valve, and the upper right oil chamber of the 1 / 2 gear three-position four-way directional control valve is communicated with the lower oil chamber of the second gear solenoid valve;

[0012] When the 3 / 4 gear manual control mechanical valve is in the left or right position under the control of the shift fork, its oil chambers are both in the cut-off state;

[0013] When the 3 / 4 gear manual control mechanical valve is in the middle position under the control of the shift fork, the upper left oil chamber of the 3 / 4 gear manual control mechanical valve is respectively connected to the lower left oil chamber of the 3 / 4 gear three-position four-way directional control valve and the lower right oil chamber of the 1 / 2 gear manual control mechanical valve, the upper right oil chamber of the 3 / 4 gear manual control mechanical valve is connected to the lower right oil chamber of the 3 / 4 gear three-position four-way directional control valve, the lower left oil chamber of the 3 / 4 gear manual control mechanical valve is connected to the oil outlet of the 3 / 4 gear oil circuit check valve; the lower right oil chamber of the 3 / 4 gear manual control mechanical valve is communicated with the fuel tank;

[0014] The upper left oil chamber of the 3 / 4 gear three-position four-way directional control valve is communicated with the lower oil chamber of the third gear solenoid valve, and the upper right oil chamber of the 3 / 4 gear three-position four-way directional control valve is communicated with the lower oil chamber of the fourth gear solenoid valve;

[0015] The 1 / 2 gear manual control mechanical valve and the 1 / 2 gear three-position four-way directional control valve are both controlled by the shift fork led out by the piston of the 1 / 2 gear shift cylinder;

[0016] The 3 / 4 gear manual control mechanical valve and the 3 / 4 gear three-position four-way directional control valve are both controlled by the shift fork led out by the piston of the 3 / 4 gear shift cylinder;

[0017] The upper left oil chamber of the first gear solenoid valve is communicated with the fuel tank, and the upper right oil chamber of the first gear solenoid valve is communicated with the rodless chamber of the 1 / 2 gear shift cylinder;

[0018] The upper left oil chamber of the 2nd gear solenoid valve is connected to the rod chamber of the 1 / 2 gear shift oil cylinder, and the upper right oil chamber of the 2nd gear solenoid valve is connected to the oil tank;

[0019] The upper left oil chamber of the 3rd gear solenoid valve is connected to the oil tank, and the upper right oil chamber of the 3rd gear solenoid valve is connected to the rod chamber of the 3 / 4 gear shift cylinder;

[0020] The upper left oil chamber of the 4-speed solenoid valve is connected to the rodless chamber of the 3 / 4-speed shift cylinder, and the upper right oil chamber of the 4-speed solenoid valve is connected to the oil tank.

[0021] The invention discloses a gear interlocking method for electro-hydraulic shifting of a tractor transmission, which is based on the gear interlocking system and is performed according to the following process:

[0022] Step 1.1: If the gear is in 1 / 2 position, go to step 1.2; otherwise, it means the gear is in 3 / 4 position, and go to step 1.5;

[0023] Step 1.2, switch the two-position three-way reversing valve to the 3 / 4 gear oil circuit;

[0024] Step 1.3, determine whether the shift fork of the 3 / 4 gear oil circuit is in the middle position. If it is in the middle position, it means that the 3 / 4 gear oil circuit is connected to the oil circuit of the gear to be engaged, so that the 1 / 2 gear oil circuit and the 3 / 4 gear oil circuit are interlocked; otherwise, execute step 1.4;

[0025] Step 1.4: Use the shift fork to manually operate the 3 / 4 gear manual mechanical valve to adjust the 3 / 4 gear oil circuit to the middle position, and then return to step 1.3;

[0026] Step 1.5, switch the two-position three-way reversing valve to the 1 / 2 gear oil circuit;

[0027] Step 1.6, determine whether the shift fork of the 1 / 2 gear oil circuit is in the middle position. If it is in the middle position, it means that the 1 / 2 gear oil circuit is connected to the oil circuit of the desired gear, so that the 3 / 4 gear oil circuit and the 1 / 2 gear oil circuit are interlocked; otherwise, execute step 1.7;

[0028] Step 1.7: Use the shift fork to manually operate the 1 / 2 gear manual mechanical valve to adjust the 1 / 2 gear oil circuit to the middle position, and then return to step 1.6.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. Based on the original tractor shift hydraulic oil circuit, the present invention adds a two-position three-way reversing valve in the front section of the gear oil circuit, realizes the autonomous switching of the hydraulic oil in the shift oil circuit, and provides the safety premise of gear interlocking;

[0031] 2. In the present invention, a manually controlled mechanical valve controlled by a shift fork is added to each of the oil circuits of the 1 / 2 gear position and the 3 / 4 gear position, ensuring that the oil circuit of the other gear position is always in the neutral position during the gear engagement process, preventing shift interference during the shifting process, preventing wear of the shifting gears, and realizing the function of gear interlock during the shifting process;

[0032] 3. In the present invention, a check valve is added between the three-position four-way directional control valve and the manually controlled mechanical valves of the two gear position oil circuits, preventing the reverse flow of hydraulic oil during the oil circuit switching process and protecting the safety of the oil circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the gear interlock system of the tractor of the present invention;

[0034] Figure 2 is a schematic diagram of the shift mechanism of the transmission system of the tractor of the present invention;

[0035] Figure 3 is a working principle diagram of the gear interlock system of the tractor of the present invention;

[0036] Figure 4 is a flow chart of the gear interlock method of the tractor of the present invention;

[0037] Reference numerals in the figures: 1 - fuel tank; 2 - oil pump; 3 - three-position four-way directional control valve; 4 - check valve for 1 / 2 gear position oil circuit; 5 - check valve for 3 / 4 gear position oil circuit; 6 - manually controlled mechanical valve for 1 / 2 gear position oil circuit; 7 - manually controlled mechanical valve for 3 / 4 gear position oil circuit; 8 - three-position four-way directional control valve for 1 / 2 gear position; 9 - three-position four-way directional control valve for 3 / 4 gear position; 10 - solenoid valve for 1st gear; 11 - solenoid valve for 2nd gear; 12 - solenoid valve for 3rd gear; 13 - solenoid valve for 4th gear; 14 - shift cylinder for 1 / 2 gear position; 15 - shift cylinder for 3 / 4 gear position; 16 - tractor body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In this embodiment, as Figure 1 shown, a gear interlock system for tractor shifting operation includes: fuel tank 1; oil pump 2; three-position four-way directional control valve 3; check valve 4 for 1 / 2 gear position oil circuit; check valve 5 for 3 / 4 gear position oil circuit; manually controlled mechanical valve 6 for 1 / 2 gear position oil circuit; manually controlled mechanical valve 7 for 3 / 4 gear position oil circuit; three-position four-way directional control valve 8 for 1 / 2 gear position; three-position four-way directional control valve 9 for 3 / 4 gear position; solenoid valve 10 for 1st gear; solenoid valve 11 for 2nd gear; solenoid valve 12 for 3rd gear; solenoid valve 13 for 4th gear; shift cylinder 14 for 1 / 2 gear position; shift cylinder 15 for 3 / 4 gear position; tractor body 16;

[0039] The fuel tank 1 supplies oil to the 1 / 2 gear shift cylinder 14 and the 3 / 4 gear shift cylinder 15 through the oil pump 2 respectively; both the 1 / 2 gear shift cylinder 14 and the 3 / 4 gear shift cylinder 15 are hinged to the tractor body 16;

[0040] The oil circuit connection sequence leading to the 1 / 2 gear shift cylinder is the fuel tank 1, the oil pump 2, the two-way three-position directional control valve 3, the one-way valve 5 for the 3 / 4 gear oil circuit, the manual control mechanical valve 7 for the 3 / 4 gear, the three-way four-position directional control valve 8 for the 1 / 2 gear, the solenoid valve 10 for the first gear or the solenoid valve 11 for the second gear, and the 1 / 2 gear shift cylinder 14; the manual control mechanical valve 7 for the 3 / 4 gear is manually operated to keep it in the middle position, and the oil passes through the three-way four-position directional control valve 8 for the 1 / 2 gear. When the left position of the three-way four-position directional control valve 8 for the 1 / 2 gear is engaged, the first gear is engaged, and when the right position is engaged, the second gear is engaged;

[0041] The oil circuit connection sequence leading to the 3 / 4 gear shift cylinder is the fuel tank 1, the oil pump 2, the two-way three-position directional control valve 3, the one-way valve 4 for the 1 / 2 gear oil circuit, the manual control mechanical valve 8 for the 1 / 2 gear, the three-way four-position directional control valve 9 for the 3 / 4 gear, the solenoid valve 12 for the third gear or the solenoid valve 13 for the fourth gear, and the 1 / 2 gear shift cylinder 15; the manual control mechanical valve 6 for the 1 / 2 gear is manually operated to keep it in the middle position, and the oil passes through the three-way four-position directional control valve 9 for the 3 / 4 gear. When the left position of the three-way four-position directional control valve 9 for the 3 / 4 gear is engaged, the third gear is engaged, and when the right position is engaged, the fourth gear is engaged;

[0042] In this embodiment, as Figure 2 shown, the 1 / 2 gear shift fork is located at the middle position between point 1 and point 2. When the fork is moved upward, the first gear is engaged, and when it is moved downward, the second gear is engaged; the 3 / 4 gear shift fork is located at the middle position between point 3 and point 4. When the fork is moved upward, the third gear is engaged, and when it is moved downward, the fourth gear is engaged; Figure 1 Among them, the manual control mechanical valve 6 for the 1 / 2 gear, the three-way four-position directional control valve 8 for the 1 / 2 gear, the manual control mechanical valve 7 for the 3 / 4 gear, and the three-way four-position directional control valve 9 for the 3 / 4 gear are respectively controlled by the 1 / 2 gear shift fork and the 3 / 4 gear shift fork;

[0043] In this embodiment, as Figure 3 shown, the Figure 1 schematic diagram of the gear interlock mechanism shown is simplified into a flow chart. After the oil circuit passes through the fuel tank oil pump and is transmitted to the directional control valve, through the manual operation of the manual control mechanical valve controlled by the shift fork, the oil circuit is kept in the middle position. The gear oil circuit directional control valve plays a role in switching gears. After the solenoid valves of each gear receive the shift signal, the shifting operation is performed, so that the hydraulic oil enters the shift cylinder, realizing gear interlock and completing the shifting operation;

[0044] In this embodiment, as Figure 4As shown, the working process of the gear interlocking system is simplified into a flow chart. First, the current gear is determined, and the two-position three-way reversing valve switches the oil circuit to another gear. It is determined whether the other gear is in the middle position at this moment. If it is, the expected gear is directly engaged. Otherwise, the other gear is manually adjusted to the middle position through the manual operation of the manual mechanical valve, and then the expected gear is engaged to achieve gear interlocking.

[0045] In this embodiment, a gear interlocking method of a tractor gear interlocking system has the following steps:

[0046] Step 1.1: If the gear is in 1 / 2 position, go to step 1.2; otherwise, it means the gear is in 3 / 4 position, and go to step 1.5;

[0047] Step 1.2, switch the two-position three-way reversing valve 3 to the 3 / 4 gear oil circuit;

[0048] Step 1.3, determine whether the shift fork of the 3 / 4 gear oil circuit is in the middle position. If it is in the middle position, it means that the 3 / 4 gear oil circuit is connected to the oil circuit of the gear to be engaged, so that the 1 / 2 gear oil circuit and the 3 / 4 gear oil circuit are interlocked; otherwise, execute step 1.4;

[0049] Step 1.4, manually operate the 3 / 4 gear manual mechanical valve 7 by using the shift fork to adjust the 3 / 4 gear oil circuit to the middle position, and then return to step 1.3;

[0050] Step 1.5, switch the two-position three-way reversing valve (3) to the 1 / 2 gear oil circuit;

[0051] Step 1.6, determine whether the shift fork of the 1 / 2 gear oil circuit is in the middle position. If it is in the middle position, it means that the 1 / 2 gear oil circuit is connected to the oil circuit of the desired gear, so that the 3 / 4 gear oil circuit and the 1 / 2 gear oil circuit are interlocked; otherwise, execute step 1.7;

[0052] Step 1.7, manually operate the 1 / 2 gear manual control mechanical valve (6) using the shift fork to adjust the 1 / 2 gear oil circuit to the middle position, and then return to step 1.6;

[0053] In summary, the improvement of the gear shifting system by the present invention can effectively improve the interference problem in the gear shifting process of the tractor, and can still ensure the gear interlocking when the gear sensor fails, thereby reducing the driver's repeated operations, making the operation more labor-saving and effectively improving the fault tolerance of the gear shifting operation, thereby improving work efficiency.

Claims

1. A gear interlock system for electro-hydraulic shifting of a tractor transmission, characterized in that, it includes: an oil tank (1), an oil pump (2), a two-position three-way directional control valve (3), a 1 / 2 gear oil circuit check valve (4), a 3 / 4 gear oil circuit check valve (5), a 1 / 2 gear manual control valve (6), a 3 / 4 gear manual control valve (7), a 1 / 2 gear four-way three-position directional control valve (8), a 3 / 4 gear four-way three-position directional control valve (9), a first gear solenoid valve (10), a second gear solenoid valve (11), a third gear solenoid valve (12), a fourth gear solenoid valve (13), a 1 / 2 gear shifting oil cylinder (14), and a 3 / 4 gear shifting oil cylinder (15); The oil tank (1) supplies oil to the 1 / 2 gear shifting oil cylinder (14) and the 3 / 4 gear shifting oil cylinder (15) respectively through the oil pump (2); When the two-position three-way directional control valve (3) is in the left position, its lower oil chamber is connected to the oil outlet of the oil pump (2), the upper right oil chamber of the two-position three-way directional control valve (3) is connected to the oil inlet of the 1 / 2 gear oil circuit check valve (4), and the upper left oil chamber of the two-position three-way directional control valve (3) is connected to the oil tank (1); When the two-position three-way directional control valve (3) is in the right position, its lower oil chamber is connected to the oil outlet of the oil pump (2), the upper left oil chamber of the two-position three-way directional control valve (3) is connected to the oil inlet of the 3 / 4 gear oil circuit check valve (5), and the upper right oil chamber of the two-position three-way directional control valve (3) is connected to the oil tank (1); When the 1 / 2 gear manual control valve (6) is in the left or right position under the control of the shift fork, its oil chamber is in a cut-off state; When the 1 / 2 gear manual control valve (6) is in the middle position under the control of the shift fork, the upper left oil chamber of the 1 / 2 gear manual control valve (6) is connected to the lower left oil chamber of the 1 / 2 gear four-way three-position directional control valve (8), the upper right oil chamber of the 1 / 2 gear manual control valve (6) is respectively connected to the lower right oil chamber of the 1 / 2 gear four-way three-position directional control valve (8) and the lower left oil chamber of the 3 / 4 gear manual control valve (7), the lower left oil chamber of the 1 / 2 gear manual control valve (6) is connected to the oil tank (1), and the lower right oil chamber of the 1 / 2 gear manual control valve (6) is connected to the oil outlet of the 1 / 2 gear oil circuit check valve (4); The upper left oil chamber of the 1 / 2 gear four-way three-position directional control valve (8) is connected to the lower oil chamber of the first gear solenoid valve (10), and the upper right oil chamber of the 1 / 2 gear four-way three-position directional control valve (8) is connected to the lower oil chamber of the second gear solenoid valve (11); When the 3 / 4 gear manual control valve (7) is in the left or right position under the control of the shift fork, its oil chamber is in a cut-off state; When the 3 / 4 gear manual control mechanical valve (7) is in the middle position under the control of the shift fork, the upper left oil chamber of the 3 / 4 gear manual control mechanical valve (7) is respectively connected to the lower left oil chamber of the 3 / 4 gear three-position four-way directional control valve (9) and the lower right oil chamber of the 1 / 2 gear manual control mechanical valve (6). The upper right oil chamber of the 3 / 4 gear manual control mechanical valve (7) is connected to the lower right oil chamber of the 3 / 4 gear three-position four-way directional control valve (9). The lower left oil chamber of the 3 / 4 gear manual control mechanical valve (7) is connected to the oil outlet of the 3 / 4 gear oil circuit check valve (5). The lower right oil chamber of the 3 / 4 gear manual control mechanical valve (7) is communicated with the fuel tank (1). The upper left oil chamber of the 3 / 4 gear three-position four-way directional control valve (9) is communicated with the lower oil chamber of the 3rd gear solenoid valve (12). The upper right oil chamber of the 3 / 4 gear three-position four-way directional control valve (9) is communicated with the lower oil chamber of the 4th gear solenoid valve (13). Both the 1 / 2 gear manual control mechanical valve (6) and the 1 / 2 gear three-position four-way directional control valve (8) are controlled by the shift fork led out by the piston of the 1 / 2 gear shift cylinder (14). Both the 3 / 4 gear manual control mechanical valve (7) and the 3 / 4 gear three-position four-way directional control valve (9) are controlled by the shift fork led out by the piston of the 3 / 4 gear shift cylinder (15). The upper left oil chamber of the 1st gear solenoid valve (10) is communicated with the fuel tank (1). The upper right oil chamber of the 1st gear solenoid valve (10) is communicated with the rodless chamber of the 1 / 2 gear shift cylinder (14). The upper left oil chamber of the 2nd gear solenoid valve (11) is communicated with the rod chamber of the 1 / 2 gear shift cylinder (14). The upper right oil chamber of the 2nd gear solenoid valve (11) is communicated with the fuel tank (1). The upper left oil chamber of the 3rd gear solenoid valve (12) is communicated with the fuel tank (1). The upper right oil chamber of the 3rd gear solenoid valve (12) is communicated with the rod chamber of the 3 / 4 gear shift cylinder (15). The upper left oil chamber of the 4th gear solenoid valve (13) is communicated with the rodless chamber of the 3 / 4 gear shift cylinder (15). The upper right oil chamber of the 4th gear solenoid valve (13) is communicated with the fuel tank (1).

2. A gear interlock method for electro-hydraulic shifting of a tractor transmission, characterized in that based on the gear interlock system described in claim 1 and carried out according to the following process: Step 1.1: If the 1 / 2 gear is engaged, then go to step 1.2; otherwise, it means the 3 / 4 gear is engaged and go to step 1.

5. Step 1.2: Switch the two-way three-position directional control valve (3) to the 3 / 4 gear oil circuit. Step 1.3: Judge whether the shift fork of the 3 / 4 gear oil circuit is in the middle position. If it is in the middle position, it means the 3 / 4 gear oil circuit is conducted to the oil circuit of the gear to be engaged, so as to realize the interlock between the 1 / 2 gear oil circuit and the 3 / 4 gear oil circuit; otherwise, go to step 1.

4. Step 1.4: Manually operate the 3 / 4 gear manual control mechanical valve (7) with the shift fork. After the 3 / 4 gear oil circuit is adjusted to the middle position, return to step 1.

3. Step 1.5: Switch the two-way three-position directional control valve (3) to the 1 / 2 gear oil circuit. Step 1.6, determine whether the shift fork of the 1 / 2 gear oil circuit is in the middle position. If it is in the middle position, it means that the 1 / 2 gear oil circuit is connected to the oil circuit of the desired gear, so that the 3 / 4 gear oil circuit and the 1 / 2 gear oil circuit are interlocked; otherwise, execute step 1.7; Step 1.7: Use the shift fork to manually operate the 1 / 2 gear manual mechanical valve (6) to adjust the 1 / 2 gear oil circuit to the middle position, and then return to step 1.6.

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