JPH09242858A - Traveling speed change structure of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate that an operater can carry out the speed change operation of a main speed changing device without the sense of incompatibility, in a traveling speed change structure of a working vehicle where a main speed change device being possible in speed change operation to plural stages and a subspeed change device equipped with a standard speed change position and a extraordinary speed change position are arranged in series. SOLUTION: Main speed change devices A, B being possible in speed change operation to plural stages and a subspeed change device C2 equipped with the standard speed change position and a extraordinary speed change position having a transmission ratio different from the standard speed change position are arranged in series, and when the main speed change devices A, B are speed changing-operated by operating the first artificial speed change tool, the sub speed change device C2 is automatically speed changing-operated to the standard speed change position in an interlocking state with the main speed change device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change structure of a traveling system in a work vehicle for working while traveling on an uneven terrain.

[0002]

2. Description of the Related Art Many agricultural tractors, which are examples of work vehicles, have a main transmission and a sub-transmission that can be operated in a plurality of stages and are arranged in series. In this case, the auxiliary transmission is configured with the standard shift position and the temporary shift position,
When the load on the aircraft changes due to a change in the condition of the work site during traveling while shifting the main transmission to a certain shift position, the auxiliary transmission shifts from the standard shift position to the temporary shift position, When the load on the machine body returns to the original state, the auxiliary transmission may be shifted from the temporary shift position to the standard shift position again.

[0003]

When the above-described sub transmission is provided, it is necessary to shift the main transmission while the sub transmission is being shifted from the standard shift position to the temporary shift position. At this time (when the traveling speed of the machine body is significantly changed, etc.), the auxiliary transmission is changed from the temporary shift position to the standard shift position, and then the main transmission is changed.

However, if the operator makes a misconception that the auxiliary transmission has already been shifted from the temporary transmission to the standard transmission, the operator leaves the auxiliary transmission in the temporary transmission. In this state, the main transmission is gear-shifted. As a result, while assuming the traveling speed of the aircraft in the state where the auxiliary transmission has been shifted to the standard shift position, the pilot intends to shift the main transmission, but in reality the auxiliary transmission is temporary. The driver feels uncomfortable because the traveling speed of the aircraft is in the state where the gear shift operation is performed to the gear shift position. The present invention relates to a traveling speed change structure of a work vehicle in which a main speed changer capable of performing a shift operation in a plurality of steps and an auxiliary speed changer having a standard speed change position and a temporary speed change position are arranged in series, and a shift is performed without a feeling of discomfort for a driver. It is intended to be configured so that it can be operated.

[0005]

[Means for Solving the Problems]

[I] According to the feature of claim 1, when it is necessary to shift the main transmission in a state where the auxiliary transmission is shifted from the standard shift position to the temporary shift position by the second artificial transmission, the gear shifting operation of the main body (the When the operator shifts the main transmission with the first artificial transmission when the traveling speed is significantly changed), the auxiliary transmission is automatically shifted from the temporary shift position to the standard shift position. If the sub-transmission is automatically returned to the standard gear position in this way, the pilot assumes that the vehicle speed is in the state where the sub-transmission is gear-shifted to the standard gear position. However, in actuality, there is no situation in which the sub-transmission will reach the traveling speed of the airframe in the state in which the auxiliary transmission is gear-shifted to the temporary gearshift position.

[II] According to the characteristics of claim 2, as in the case of claim 1, the "action" described in the above [I] is provided, and in addition to this, the following "action" is provided. ing. Many work vehicles such as agricultural tractors are equipped with a forward / reverse switching device in addition to the main and auxiliary transmissions as described above. In this case, if the above-described auxiliary transmission is simply arranged on the lower side of the forward / reverse switching device (the lower side of both the forward drive side and the reverse drive side), the standard transmission speed of the auxiliary transmission can be reduced in both the forward drive and the reverse drive. Gear shifting operation can be performed at the temporary gear position.
However, if the auxiliary transmission is simply arranged on the lower side of the forward / reverse switching device (on the lower side of both the forward and reverse sides), the length from the front end of the forward / reverse switching device to the rear end of the auxiliary transmission is reduced. The length of the forward / reverse switching device and the length of the auxiliary transmission device become a simple sum, and the overall length becomes long.

On the other hand, according to the second aspect of the present invention, the auxiliary transmission is arranged below the forward side of the forward / reverse switching device, and the auxiliary transmission is not arranged below the reverse side. As a result, the transmission system on the reverse side of the forward / reverse switching device and the auxiliary transmission are arranged in parallel, and the front part of the auxiliary transmission can be inserted into the rear part of the forward / reverse switching device. The length from the front end of the forward / reverse switching device to the rear end of the auxiliary transmission can be shortened by the amount that the front part of the auxiliary transmission is inserted. It can be said that most work vehicles such as agricultural tractors actually move forward while there is almost no work moving backward.
As a result, even if the auxiliary transmission is arranged on the lower side of the forward side of the forward / reverse switching device and the auxiliary transmission is not arranged on the lower side of the reverse side as in the second aspect of the invention, the work surface is reduced. There is no hindrance.

[III] According to the characteristics of claim 3, as in the case of claim 2, the "action" described in the above [II] is provided, and in addition to this, the following "action" is provided. ing. Many work vehicles such as agricultural tractors are equipped with a forward / reverse switching device and an auxiliary sub transmission in addition to the main and sub transmissions described above. According to the feature of claim 3, in a state in which the second artificial gear shifts the auxiliary transmission from the standard gear shift position to the temporary gear shift position, the operator shifts the auxiliary auxiliary gear shift by the third artificial gear. Even if the forward / reverse switching device is switched by the manual switching operation tool, the auxiliary transmission device automatically shifts from the temporary shift position to the standard shift position as in the case where the first transmission device shifts the main transmission device. The gear is operated. As a result, even though the pilot intends to shift the auxiliary transmission or the forward / reverse switching device while assuming the traveling speed of the aircraft when the auxiliary transmission is shifted to the standard shift position, ,
In reality, there is no situation in which the traveling speed of the airframe when the auxiliary transmission is gear-shifted to the temporary gearshift position is reached.

[IV] According to the feature of claim 4, as in any one of claims 1, 2 and 3, any one of the preceding [I], [II] and [III] In addition to this, the following "action" is provided. In particular, in many main transmissions having a large number of gear shift positions, the difference in transmission ratio between adjacent gear shift positions is often small. If the auxiliary transmission is configured to automatically shift to the standard gear position when a gear shift operation is performed, the transmission ratio before the gear shift operation (before the gear shift operation of the main gear shift, the temporary gear shift position of the sub gear shift Transmission ratio) and the transmission ratio after the gear change operation (the transmission ratio at the standard gear position of the auxiliary transmission after the gear change operation of the main transmission) are close to each other, and due to fluctuations in the engine speed, In reality, the flight speed of the airframe hardly changes and the operator may feel uncomfortable.

According to a fourth aspect of the present invention, in a state in which the second artificial gear shifts the auxiliary transmission from the standard gear shift position to the temporary gear shift position, the operator uses the first artificial gear to shift the main gear shift to a predetermined gear. When the gear is operated by less than the number of gears (for example, when the predetermined number of gears is two, the main transmission is in the state of being geared by one gear, and the predetermined number of gears is three.
In the case of the gear position, the main transmission device is shifted by two gears), and the auxiliary transmission device is left in the temporary gear position. As a result, as described above, the transmission ratios before and after the gear shifting operation are close to each other,
In reality, a situation where the traveling speed of the airframe hardly changes does not occur.

On the contrary, when the operator shifts the main transmission by the first artificial transmission to a predetermined number of gears or more (for example, when the predetermined number of gears is two, the main transmission is two or more gears). When the predetermined number of gears is three, the main transmission is geared to three or more gears),
The auxiliary transmission is automatically operated to shift from the temporary shift position to the standard shift position.

[V] According to the feature of claim 5, as in any one of claims 1, 2 and 3, any one of the preceding paragraphs [I], [II] and [III] In addition to this, the following "action" is provided. Depending on the relationship between the standard and temporary shift positions of the auxiliary transmission and the respective shift positions of the main transmission, the operator automatically shifts the main transmission to the low speed side using the first artificial transmission, and the auxiliary transmission automatically operates. When the gear is operated to the standard gear position, the gear ratio before the gear change operation (the gear ratio at the temporary gear position of the auxiliary gearbox before the gear change operation of the main gearbox) and the gear ratio after the gear change operation (main gearbox After the gear shift operation of, the transmission ratio at the standard gear shift position of the auxiliary transmission becomes close to each other,
Due to fluctuations in the engine speed, the traveling speed of the aircraft may hardly change and the operator may feel uncomfortable.

According to the fifth aspect of the invention, when the operator shifts the main transmission to the high speed side by the first artificial transmission, the auxiliary transmission is automatically shifted to the standard shift position. When the shift operation is performed to the low speed side, the auxiliary transmission is not automatically shifted to the standard shift position. As a result, as described above, the transmission ratios before and after the gear shifting operation are close to each other,
In reality, a situation where the traveling speed of the airframe hardly changes does not occur.

[VI] According to the characteristics of claim 6, as in any one of claims 1, 2 and 3, any one of the above [I], [II] and [III] In addition to this, the following "action" is provided. Depending on the relationship between the standard / temporary shift position of the auxiliary transmission and each shift position of the main transmission, the operator automatically shifts the main transmission to the high speed side with the first artificial transmission, and the auxiliary transmission automatically operates. When the gear is operated to the standard gear position, the gear ratio before the gear change operation (the gear ratio at the temporary gear position of the auxiliary gearbox before the gear change operation of the main gearbox) and the gear ratio after the gear change operation (main gearbox After the gear shift operation of, the transmission ratio at the standard gear shift position of the auxiliary transmission becomes close to each other,
Due to fluctuations in the engine speed, the traveling speed of the aircraft may hardly change and the operator may feel uncomfortable.

According to the feature of claim 6, when the operator shifts the main transmission to the low speed side by the first artificial transmission, the auxiliary transmission is automatically shifted to the standard shift position. When shifting to the high speed side, the auxiliary transmission is not automatically shifted to the standard shifting position. As a result, as described above, the transmission ratios before and after the gear shifting operation are close to each other,
In reality, a situation where the traveling speed of the airframe hardly changes does not occur.

[VII] According to the feature of claim 7, as in the case of any one of claims 1 to 6, the "action" according to any one of the preceding paragraphs [I] to [VI] In addition to this, the following "action"
It has. For work vehicles such as agricultural tractors, when the load applied to the machine is a little increased due to changes in the work site while the vehicle is moving forward while shifting the main transmission to a certain shift position, When the load on the machine body returns to the original state by performing the gearshift operation to the side to suppress the decrease of the traveling speed of the machine body, the main transmission or the like may be shifted to the original gear position.

According to a seventh aspect of the present invention, the auxiliary transmission is shifted to the standard shift position, and the main transmission is shifted to a certain shift position. When the applied load becomes a little heavy, the auxiliary transmission can be operated to shift from the standard speed change position to the low speed temporary speed change position. When the load applied to the aircraft returns to the original state, the first speed change by the first artificial transmission It is only necessary to shift the auxiliary transmission to the original standard shift position by shifting the device.

[VIII] According to the features of claim 8, as in the case of any one of claims 1 to 7, the "action" according to any one of the preceding paragraphs [I] to [VII] In addition to this, the following "action"
It has. According to the feature of claim 8, the load applied to the airframe due to a change in the state of the work site during forward movement by shifting the auxiliary transmission to the standard shifting position and shifting the main transmission to a certain shifting position. When there is a change, the auxiliary transmission may be shifted from the standard shift position to the temporary shift position, and when the load on the machine body returns to the original state, the auxiliary transmission may be shifted to the original temporary shift position. in this case,
Since the difference in the transmission ratio between the standard transmission position and the temporary transmission position in the sub transmission is set to be smaller than the difference in the transmission ratio between the respective transmission positions in the main transmission, as described above. By shifting the auxiliary transmission from the standard shifting position to the temporary shifting position, it can be easily said that the shifting operation is performed to a shifting position having a transmission ratio slightly different from the current shifting position.

[IX] According to the feature of claim 9, the same as the case of any one of claims 1 to 8, the above-mentioned [I]
~ "Action" according to any one of [VIII]
In addition to this, the following "action" is provided. According to the feature of claim 9, the pilot can perform the gear shift operation of the main transmission by holding and operating the gear shift lever by hand, and by operating the operation switch by the hand holding the gear shift lever, The shift operation of the transmission can be performed.

[X] According to the characteristics of claim 10, the same as the case of any one of claims 1 to 9,
To [IX], the "action" described in any one of the above is provided, and in addition to this, the following "action" is provided. According to the feature of claim 10, if the automatic return means is switched to the operation stop state depending on the situation of the work place, etc., after the auxiliary transmission is shifted from the standard shift position to the temporary shift position by the second artificial transmission, Even if a shift operation of the main transmission is performed by the first artificial transmission, the sub transmission can be left in the temporary shift position without being shifted to the standard shift position. After that, the operator can operate the second artificial transmission as necessary to shift the auxiliary transmission from the temporary shift position to the standard shift position.

[XI] According to the features of claim 11, as in the case of any one of claims 1 to 10, the "action" according to any one of the preceding paragraphs [I] to [X] "
And the following “action” in addition to this. According to the feature of claim 11, the operator can visually confirm the shift state of the auxiliary transmission, which is the standard shift position or the temporary shift position.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) FIG. 1 shows a transmission system of an agricultural tractor, which is an example of a work vehicle, in which power from an engine 1 is used as a main clutch 2,
First main transmission A (corresponding to main transmission), multi-plate hydraulic clutch 3 for travel shifting, first auxiliary transmission C, second main transmission B (corresponding to main transmission), second auxiliary transmission The power transmitted to the rear wheel 4 via the device D (corresponding to an auxiliary subtransmission device) and the rear wheel differential mechanism 4a, and the power branched from immediately before the rear wheel differential mechanism 4a is transmitted via the transmission shaft 5 and the front wheel differential mechanism 6a. Front wheel 6
Is transmitted to Power from the engine 1 is transmitted to the PTO shaft 8 via the PTO transmission 7.

The first main transmission A is a synchromesh type gear shift type having two sets of shift members 9 and 10 and is configured to be capable of shifting in four stages, and the second main transmission B is also one.
A gear shift type of a synchromesh type including a pair of shift members 30 is configured to be capable of shifting in two stages, and can be shifted in eight stages by the first and second main transmission devices A and B.
The shift members 9 and 10 of the first main transmission A are slid by the first and second hydraulic cylinders 11 and 12,
The shift member 30 of the second main transmission B is slid by the third hydraulic cylinder 13. Second auxiliary transmission D
Is a gear shift type having a pair of shift members 31 and is configured to be capable of shifting in two stages. The shift member 31 is directly slid by an auxiliary shift lever 43 (corresponding to a third artificial transmission).

(2) Next, the first auxiliary transmission C will be described. As shown in FIGS. 2 and 1, the first auxiliary transmission C includes a synchromesh type forward / reverse switching unit C1 (corresponding to a forward / reverse switching device) including a shift member 47 and a shift member 4.
It is composed of a synchromesh type including 8 and a transmission unit C2 (corresponding to an auxiliary transmission) capable of shifting in two stages.

The forward / reverse switching portion C1 is constructed by a transmission shaft 44 from the hydraulic clutch 3 having a reverse gear 45 and a forward movement cylindrical shaft 46 fitted on the transmission shaft 44 so as to be rotatable relative to each other. When the member 47 is slid rightward on the paper surface to be engaged with the reverse gear 45, the power of the transmission shaft 44 passes from the reverse gear 45, the intermediate gear 55, and does not pass through the speed change section C2 but in the reverse state. Transmission shaft 49 to main transmission B
Is transmitted to On the contrary, when the shift member 47 is slid to the left side of the drawing to engage the forward cylindrical shaft 46, the transmission shaft 4
The power of No. 4 is transmitted to the forward cylindrical shaft 46 in the normal rotation state, and the shift member 47 is directly slid by the forward / backward lever 16 (corresponding to a manual switching operation tool).

As shown in FIGS. 2 and 1, the transmission unit C2 is
A high speed gear 50 is relatively rotatably fitted on the forward cylindrical shaft 46, and a low speed gear 51 is relatively rotatably fitted on the transmission shaft 44. The shift member 48 provided on the forward cylindrical shaft 46 is slid rightward on the paper surface to move the high speed gear 5
When it is occluded to 0 (corresponding to the standard shift position), the power of the forward cylindrical shaft 46 is transmitted to the transmission shaft 49 in a normal rotation high speed state. On the contrary, when the shift member 48 is slid to the left side of the drawing to be engaged with the low speed gear 51 (corresponding to a temporary gear shift position), the power of the forward cylindrical shaft 46 is transmitted to the transmission shaft 49 in the normal low speed state. Therefore, the shift member 48 is slid by the fourth hydraulic cylinder 14. in this case,
The difference in the transmission ratio between the high speed gear 50 and the low speed gear 51 in the speed change portion C2 is the difference between the first and second main transmissions A, which will be described later.
It is set to be smaller than the difference in transmission ratio between the respective shift positions of B (shift lever 33).

Next, the fourth hydraulic cylinder 14 of the speed change section C2.
Will be described. As shown in FIG. 3, an electromagnetic operation valve 22 for supplying and discharging hydraulic oil is provided in an oil chamber on the left side of the fourth hydraulic cylinder 14, and an oil chamber to be described later is provided in the oil chamber on the right side of the fourth hydraulic cylinder 14. An oil passage 27 branched from the passage 17 is connected so that hydraulic oil is constantly supplied. Solenoid operated valve 2
2 is a 3-port type equipped with a hydraulic oil input port, a hydraulic oil output port, and a hydraulic oil drain port, and is configured to be freely operable in two positions: a supply position for supplying hydraulic oil and a discharge position for discharging hydraulic oil. And is biased toward the supply position side by a spring.

When the solenoid operated valve 22 is operated to the supply position by the above structure, the piston 14a moves to the right side of the drawing as shown in FIG. 3 due to the difference in the pressure receiving area of the piston 14a. C2 shift member 48
Is in a state of being engaged with the high speed gear 50. Next, when the electromagnetic operation valve 22 is operated to the oil discharge position, the piston 14a moves to the left side of the drawing due to the hydraulic oil supplied from the oil passage 27. This state causes the shift member 48 of the speed change unit C2 to move to the low speed gear 51. It is in the state of being occluded.

(3) Next, the first and second hydraulic cylinders 11 and 12 of the first main transmission A will be described. As shown in FIG. 3, a large-diameter cylinder portion and a small-diameter cylinder portion are formed, and a large-diameter piston 23 and a small-diameter piston 24 are slidably housed therein. The first and second hydraulic cylinders 11 and 12 are configured by being slidably inserted.

An electromagnetic operation valve 25 for supplying / discharging operating oil is provided on the right side of the small diameter piston 24 in the drawing, and an electromagnetic operation valve 26 for supplying / discharging operating oil is provided on the left side of the large diameter piston 23 in the drawing. The solenoid operated valves 25, 26 are three-port type equipped with an input port for hydraulic oil, an output port for hydraulic oil, and a drain port for hydraulic oil. The first and second hydraulic cylinders 11, 1
It is configured to be operable at two positions, a supply position for supplying hydraulic oil to 2 and a discharge position for discharging hydraulic oil, and is biased toward the supply position side by a spring.

With the above construction, both solenoid operated valves 25,
When 26 is operated to the supply position, the large-diameter piston 23 has a larger pressure receiving area than the small-diameter piston 24, as shown in the second hydraulic cylinder 12 of FIG. The large-diameter and small-diameter pistons 23 and 24 try to move to the right in the drawing while the pistons 23 and 24 press each other, and the large-diameter piston 23 hits the stepped portion of the large-diameter and small-diameter cylinders, and at this position. Large and small diameter pistons 23, 24 are retained. This state is the neutral stop position of the shift members 9 and 10 shown in FIG.

Next, when the solenoid operated valve 25 is operated to the oil draining position with the solenoid operated valve 26 left in the supply position, as shown in the first hydraulic cylinder 11 of FIG.
The small-diameter piston 24 moves to the right on the paper surface. This state is a state in which the shift members 9 and 10 shown in FIG. 1 are slid rightward on the paper surface and engage with the transmission gear. On the contrary, when the solenoid operated valve 26 is operated to the oil draining position with the solenoid operated valve 25 left at the supply position, the large diameter and small diameter pistons 2
3, 24 move to the left side of the paper together. This state is shown in FIG.
The shift members 9 and 10 shown in (1) are slid to the left side of the drawing and engaged with the transmission gear.

Next, the third hydraulic cylinder 13 of the second main transmission B will be described. As with the fourth hydraulic cylinder 14, as shown in FIG. 3, an electromagnetic operation valve 29 for supplying and discharging hydraulic oil is provided in an oil chamber on the right side of the third hydraulic cylinder 13 in the drawing, and the left side of the third hydraulic cylinder 13 in the drawing is shown. An oil passage 28 branched from an oil passage 17, which will be described later, is connected to the oil chamber of FIG. The solenoid operated valve 29 is a 3-port type equipped with a hydraulic oil input port, a hydraulic oil output port, and a hydraulic oil drain port, and is operated at two positions: a supply position for supplying hydraulic oil and a discharge position for discharging hydraulic oil. It is configured freely and is biased toward the supply position side by a spring.

When the electromagnetically operated valve 29 is operated to the supply position with the above structure, the piston 13a moves to the left side of the drawing as shown in FIG. 3 due to the difference in the pressure receiving area of the piston 13a. The main transmission B is in the low speed state. Next, when the solenoid operated valve 29 is operated to the oil drain position, the piston 13 is driven by the hydraulic oil supplied from the oil passage 28.
a moves to the right on the paper surface, and this state is the high speed state of the second main transmission device B.

(4) Next, a hydraulic circuit for the first, second, third, fourth hydraulic cylinders 11, 12, 13, 14 and the hydraulic clutch 3 will be described. As shown in FIG. 3, oil passages 17 and 18 are branched in parallel from the pump 15, and a pressure control valve 21 of an electromagnetic proportional type and an operation valve 3 are provided in the oil passage 18.
5 are connected in series, and the hydraulic clutch 3 is connected to the lower side of the operation valve 35. The operation valve 35 supplies the hydraulic oil to the hydraulic clutch 3 and transmits the hydraulic oil to the supply position 3
5a and the hydraulic clutch 3 is a pilot operated type that can be operated at an oil discharge position 35b for discharging hydraulic oil and transmitting and shutting off the oil, and is urged by a spring toward the oil discharge position 35b. The pilot oil passage 20 is branched from the lower side of the throttle portion 19 in the oil passage 17, and the pilot oil passage 2
0 is connected to the operation valve 35.

The solenoid operated valves 22, 25, 26, 29 described above are connected to the oil passage 17 on the upstream side of the throttle portion 19. From the throttle portion 19 in the oil passage 17 to the lower side,
Open / close valves 36, 37, 38, 39, 40 biased to the closing side
Is connected. First, second, third, fourth hydraulic cylinder 11
14 to 14, a recess is formed in the piston rod at a position corresponding to the shift position (first speed position, second speed position, low speed position, etc.), and the neutral portion between the shift positions is formed in a convex shape. ing. A linkage mechanism 32 for opening and closing the on-off valves 36 to 39 is provided between the shift positions. On the shift shaft for sliding operation of the shift member 47 in the forward / reverse switching portion C1 of the first auxiliary transmission C, the same recessed portions and convex neutral portions as described above are formed, and between the forward drive side and the reverse drive side. A linkage mechanism 32 for opening and closing the opening / closing valve 40 is provided.

A gear shift lever 33 (first gear position) which is manually operated by the operator and has an operation position of 1st speed position to 8th speed position.
A signal from a potentiometer 34 for detecting the operation position of the speed change lever 33 is input to the control device 42, and the control device 42 controls the electromagnetic operation valve 25 based on the operation of the speed change lever 33. , 26, 29 are operated. A button type operation switch 52 (corresponding to a second artificial transmission) is provided on the grip portion of the speed change lever 33,
The control device 42 operates the electromagnetic operation valve 22 based on the operation of the operation switch 52. A pressure sensor 41 for detecting the pilot pressure of the pilot oil passage 20 is provided on the lower side of the throttle portion 19 in the oil passage 17, and the pressure sensor 41 is provided.
Signal is input to the control device 42.

(5) Next, the shift operation of the first and second main transmissions A and B by the shift lever 33 will be described.
The state shown in FIG. 3 is a state in which the speed change lever 33 is operated to the first speed position, the first hydraulic cylinder 11 is in the first speed position of the first main transmission device A, the second hydraulic cylinder 12 is in the neutral stop position, and The third hydraulic cylinder 13 is in the low speed position of the second main transmission device B, and the forward / reverse lever 16 is in the forward drive first speed state. As a result, the operation valve 35 is operated to the supply position 35a by the pilot pressure in the pilot oil passage 20, and the hydraulic clutch 3 is operated for transmission.

In this first forward speed state, the speed change lever 33
Is operated to, for example, the second speed position, the first hydraulic cylinder 11
The solenoid operated valve 25 of is operated from the oil discharge position to the supply position,
The solenoid operated valve 26 of the first hydraulic cylinder 11 is operated from the supply position to the discharge position. As a result, the large-diameter and small-diameter pistons 23, 24 of the first hydraulic cylinder 11 start moving from the first speed position shown in FIG. 3 to the left in the drawing, and the shift member 9 starts sliding operation.

The open / close valve 36 is opened by the linkage mechanism 32 during the movement of the large-diameter and small-diameter pistons 23, 24 of the first hydraulic cylinder 11 (since the second hydraulic cylinder 12 is in the neutral stop position, The on-off valve 37 has already been opened.) As a result, the pilot pressure in the pilot oil passage 20 decreases, the operating valve 35 is operated from the supply position 35a to the oil discharge position 35b by the urging force of the spring, and the hydraulic clutch 3 is transmission interrupted.

Next, when the sliding operation of the shift member 9 by the first hydraulic cylinder 11 is completed and the first main transmission A is shifted to the second speed position, the linkage mechanism 32 closes the opening / closing valve 36. The pilot pressure in the pilot oil passage 20 rises again, and the operation valve 35 is operated from the oil discharge position 35b to the supply position 35a. When the pressure sensor 41 detects that the pilot pressure has decreased and increased again in the pilot oil passage 20 as described above, the control device 4
2, the pressure control valve 21 is operated, and the hydraulic clutch 3
The hydraulic oil pressure supplied to the hydraulic clutch 3 is gradually increased or rapidly increased based on the operation position of the shift lever 33 or the like, and the hydraulic clutch 3 is transmitted.

Similar to the above-described gear shifting operation, the gear shifting lever 33
Is operated between the second speed position and the third speed position, the first and second hydraulic cylinders 11 and 12 shift the first main transmission device A to move the speed change lever 33 to the third speed position and the fourth speed position. If operated over, the first hydraulic cylinder 12
The main transmission A is operated to change gears. When the speed change lever 33 is operated between the fourth speed position and the fifth speed position, the first, second and third main transmissions A and B are operated to change gears by the first, second and third hydraulic cylinders 11, 12 and 13, and the speed change lever 33 is operated. If 33 is operated between the fifth speed position and the sixth speed position, the first hydraulic cylinder 11
Thus, the first main transmission A is operated to change gears,
When the speed change lever 33 is operated between the 6th speed position and the 7th speed position, the first and second hydraulic cylinders 11 and 12 are used to make the first
When the main transmission A is operated to change gears and the transmission lever 33 is operated between the 7th speed position and the 8th speed position, the second hydraulic cylinder 1
The first main transmission device A is operated by 2 for shifting. When the forward / reverse lever 16 is operated from the forward side to the reverse side, the opening / closing valve 40 is opened / closed by the linkage mechanism 32, and similarly to the above, the hydraulic clutch 3 is automatically disconnected / transmitted by the operation valve 35. To be done.

(6) Next, the first operation by the operation switch 52
The gear shifting operation of the gear shifting portion C2 of the auxiliary gearbox C will be described with reference to FIG. In the initial state of the speed change portion C2 of the first auxiliary speed change device C, the electromagnetically operated valve 22 is operated to the supply position by the urging force of the spring, and the piston 14a of the fourth hydraulic cylinder 14 moves to the right in the drawing of FIG. Therefore, the shift member 48 of the speed change unit C2 meshes with the high speed gear 50.

In this state, when the operation switch 52 of the shift lever 33 shown in FIG. 3 is once pushed (step S1), the control device 42 operates the electromagnetic operation valve 22 from the supply position to the oil discharge position. As a result, the oil passage 27
The piston 14a of the fourth hydraulic cylinder 14 begins to move to the left in the drawing by the hydraulic oil supplied from the operation mechanism, and the opening / closing valve 38 is opened by the linkage mechanism 32 accordingly, and the operation valve 35
Is operated to the oil drainage position 35b, and the hydraulic clutch 3 is transmission-interrupted. Next, when the shift member 48 is engaged with the low speed gear 51 by the fourth hydraulic cylinder 14, the linkage mechanism 32
By this, the on-off valve 38 is closed, the operation valve 35 is operated to the supply position 35a, and the hydraulic clutch 3 is transmitted (above, steps S2 and S3), and the display lamp 53 is turned on (corresponding to display means) ( Step S4).

In this case, the high speed gear 5 in the transmission unit C2
0 and the transmission ratio difference between the low speed gear 51 are
It is set to be smaller than the difference in transmission ratio between the respective gear shift positions of the main transmissions A and B (gear lever 33). As a result, for example, when the shift lever 33 is operated to the 2nd speed position, the operation switch 52 is pushed and the shift member 48 of the transmission unit C2 is engaged with the low speed gear 51 as described above. The transmission state is achieved at a transmission ratio intermediate between the position and the first speed position.

In the above-mentioned state, if the operation switch 52 of the shift lever 33 is pushed again (step S
1), the control device 42 operates the electromagnetically operated valve 22 from the oil discharge position to the supply position, and the shift member 48 of the speed change unit C2.
Engages from the low speed gear 51 to the high speed gear 50,
The hydraulic clutch 3 is automatically disengaged and operated by the on-off valve 38 and the operation valve 35 (steps S2 and S).
5) The display lamp 53 is turned off (step S6).

(7) Next, in a state in which the shift member 48 of the speed change portion C2 in the above-described first auxiliary transmission C is engaged with the low speed gear 51 and the display lamp 53 is lit (steps S3 and S4). (The rear state), the operator selects the gearshift lever 3
It is assumed that 3 is operated to shift the first and second main transmissions A and B (see (5) above) (step S8).
In this case, the predetermined number N of gears of two or more (for example, two or three) is set in advance, and the first and second main transmissions A and B are driven by the gear shift lever 33 to a high speed of N or more. When the shift operation is performed to the side or the low speed side (for example, the shift operation is performed to the high speed side by two or three or more steps or the low speed side) (step S9), the electromagnetic valve 22 is automatically operated by the control device 42 by shifting to step S5. The shift member 48 of the speed change unit C2 is automatically engaged with the high speed gear 50 from the low speed gear 51 by being operated from the oil discharge position to the supply position.
The hydraulic clutch 3 is automatically disengaged and operated by the control valve 8 and the operation valve 35 (step S5), and the display lamp 53 is extinguished (step S6) (the above corresponds to the automatic resetting means).

As described above, in the state where the shift member 48 of the speed change portion C2 of the first auxiliary transmission C is engaged with the low speed gear 51 and the display lamp 53 is lit (the state after steps S3 and S4). ), The pilot operates the auxiliary transmission lever 4
3 to operate the second auxiliary transmission device D (step S10), or to operate the forward / reverse lever 16 to move the first auxiliary
When the forward / reverse switching portion C1 of the auxiliary transmission C is switched (step S11), the process proceeds to step S5 in the same manner as described above, and the control device 42 causes the electromagnetically operated valve 22 to automatically move from the oil discharge position to the supply position. The shift member 48 of the speed change unit C2 is automatically engaged with the low speed gear 51 and the high speed gear 50 by the operation of the switch C2. Then, the display lamp 53 is turned off (step S5) (step S6) (the above is equivalent to the automatic resetting means).

As shown in FIG. 3, a changeover switch 54 (corresponding to changeover means) is provided, and when the changeover switch 54 is switched to the operating position ON (step S7),
As described above, the speed change operation of the first and second main transmissions A and B by the speed change lever 33, the speed change operation of the second auxiliary speed change device D by the auxiliary speed change lever 43, and the forward-reverse switching portion C1 by the forward-reverse drive lever 16 are performed. When the switching operation is performed, the automatic engagement operation of the shift member 48 of the speed change unit C2 to the high speed gear 50, the automatic transmission interruption and transmission operation of the hydraulic clutch 3, and the turning off of the display lamp 53 are performed.

On the contrary, the changeover switch 54 is set to the operation stop position O.
After switching to FF (step S7), as described above, the first and second main transmissions A by the transmission lever 33,
Even if the shift operation of B, the shift operation of the second auxiliary transmission device D by the auxiliary shift lever 43, and the switching operation of the forward / reverse switching section C1 by the forward / reverse lever 16 are performed, the above-described shift section C2
The automatic engagement operation of the shift member 48 of the shift gear 48 to the high speed gear 50 is not performed, the shift member 48 of the transmission unit C2 remains engaged with the low speed gear 51, and the display lamp 53 remains lit. In this case, when the operation switch 52 is pushed, the engagement operation of the shift member 48 of the speed change unit C2 to the high speed gear 50 is performed as described in (6) above.

[Other Embodiments of the Invention] Step S9 in the configuration of FIG. 4 is deleted, and even if the first and second main transmissions A and B have one or more gears, the gear shift lever 33 shifts to the high speed side or the low speed side. Then, the process may proceed to step S5. In the configuration of FIG. 4, steps S8 and S
Instead of 9, the shift lever 33 may be configured to shift to step S5 only when the first and second main transmissions A and B are shifted to the high speed side.
Thus, the process may shift to step S5 only when the first and second main transmissions A and B are operated to shift to the low speed side.

[0052]

According to the features of the first aspect of the invention, when the main transmission is operated to shift, the sub-transmission is automatically shifted to the standard shift position. Although the pilot intends to shift the main transmission while assuming the traveling speed of the aircraft in the position where the auxiliary transmission is in the temporary shift position, Since there is no situation where the vehicle travels at the traveling speed, the driver no longer feels uncomfortable, and it is possible to prevent the operator's erroneous operation based on this uncomfortable feeling. When the main transmission is greatly shifted to the high speed side, the difference in running speed between the standard transmission position and the temporary transmission position of the sub transmission may become large. In this case, the features of claim 1 become effective. Further, according to the feature of the first aspect, when performing the gear shifting operation of the main transmission device, it is not necessary to manually shift the auxiliary transmission device to the standard gear shift position, so that the operability is improved.

According to the feature of claim 2, as in the case of claim 1, the "effect of the invention" of claim 1 is provided. According to the feature of claim 2, paying attention to the fact that the shift operation to the temporary shift position of the auxiliary transmission is hardly performed when the vehicle is moving backward, and by providing the auxiliary transmission as described above only on the forward side, This is advantageous in terms of overall compactness and simplification of the structure.

According to the feature of claim 3, as in the case of claim 2, the above-mentioned "effect of the invention" of claim 2 is provided. According to the third aspect of the present invention, the auxiliary transmission is automatically shifted to the standard shift position by the shifting operation of the auxiliary sub transmission other than the main transmission and the switching operation of the forward / reverse switching device. Assuming the traveling speed of the aircraft when the device is operated to the standard gear position, the pilot intends to perform the auxiliary gear shifting operation or the forward / reverse switching device switching operation, but in reality There will be no situation where the speed of the aircraft will change to the running speed of the aircraft when the transmission is operated to the temporary shift position, and the operator will not feel uncomfortable. I was able to prevent it.

According to the feature of claim 4, as in the case of any one of claims 1 to 3, the "effect of the invention" of any one of claims 1 to 3 is provided. According to the feature of claim 4, particularly in the main transmission having a large number of shift positions, when the auxiliary transmission is automatically shifted to the standard shift position in accordance with the shift operation of the main transmission, the traveling speed of the machine body is increased. It was possible to prevent the erroneous operation caused by the driver feeling uncomfortable by suppressing the condition that the value of the ∘ changes little.

According to the feature of claim 5, as in the case of any one of claims 1 to 3, the "effect of the invention" of any one of claims 1 to 3 is provided. According to the feature of claim 5, when the sub-transmission is automatically shifted to the standard shift position in response to the low-speed shift operation of the main transmission, the standard and temporary shift positions of the sub-transmission and the main transmission are changed. Due to the relationship with each shift position, it was possible to prevent a situation in which the traveling speed of the aircraft hardly changed, and to prevent an erroneous operation caused by the driver feeling uncomfortable.

According to the feature of claim 6, as in the case of any one of claims 1 to 3, the "effect of the invention" of any one of claims 1 to 3 is provided. According to the feature of claim 6, when the auxiliary transmission is automatically shifted to the standard shift position in response to the high-speed shift operation of the main transmission, the standard and temporary shift positions of the auxiliary transmission and the main transmission are changed. Due to the relationship with each shift position, it was possible to prevent a situation in which the traveling speed of the aircraft hardly changed, and to prevent an erroneous operation caused by the driver feeling uncomfortable.

According to the feature of claim 7, as in the case of any one of claims 1 to 6, the "effect of the invention" of any one of claims 1 to 6 is provided. According to the feature of claim 7, when the load applied to the machine body is slightly increased, the auxiliary transmission is shifted from the standard shift position to the temporary shift position on the low speed side, and when the load applied to the machine body returns to the original state, It is possible to say that the auxiliary transmission is shifted to the original standard shift position by the shift operation of the main transmission by the one-manual transmission and the like, so that the workability is improved.

According to the feature of claim 8, as in the case of any one of claims 1 to 7, the "effect of the invention" of any one of claims 1 to 7 is provided. According to the feature of claim 8, the shift operation of the auxiliary transmission from the standard shift position to the temporary shift position can be easily performed to shift to a shift position having a slightly different transmission ratio from the current shift position. , Workability will be improved.

According to the feature of claim 9, as in the case of any one of claims 1 to 8, the "effect of the invention" of any one of claims 1 to 8 is provided. According to the feature of claim 9, both the gear shift lever for the main transmission device and the operation switch for the auxiliary transmission device can be operated with one hand, so that the operability is improved.

According to the features of claim 10, claims 1 to 9 are provided.
The effect of the invention is provided in any one of claims 1 to 9 as in the case of any one of the above. According to the feature of claim 10, even if the gear shifting operation of the main transmission or the like is performed depending on the situation of the work place, it is possible to cope with the case where it is better to leave the auxiliary transmission in the temporary gear shift position. , Workability will be improved.

According to the characteristics of claim 11, claims 1 to 1
1 to 10 as in the case of any one of 0
It has any one of the "effects of the invention".
According to the feature of claim 11, the operator can visually check the gear shift state of the auxiliary transmission such as whether it is the standard gear shift position or the temporary gear shift position. Therefore, misunderstanding by the pilot can be reduced. As a result, it was possible to prevent erroneous operation based on the operator's misunderstanding.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a traveling transmission system.

FIG. 2 is a vertical sectional side view of a first auxiliary transmission device.

FIG. 3 is a hydraulic circuit diagram for the first, second, third and fourth hydraulic cylinders.

FIG. 4 is a diagram showing a flow of control at the time of operating an operation switch, a shift lever, etc.

[Explanation of symbols]

 16 Artificial switching operation device 33 First artificial transmission device, shift lever 43 Third artificial transmission device 52 Second artificial transmission device, operation switch 53 Display means 54 Switching means A, B Main transmission device C1 Forward / reverse switching device C2 Auxiliary transmission device D Auxiliary auxiliary transmission device N Predetermined shift speed

Claims (11)

[Claims] 1. A sub-transmission device (C2) comprising main transmission devices (A), (B) capable of shifting operation in a plurality of stages and a standard transmission position and a temporary transmission position having a transmission ratio different from the standard transmission position. Are arranged in series and are operated artificially. The main transmission (A),
(B) is provided with a first artificial speed changer (33) and a second artificial speed changer (52) that is operated manually to change the speed of the auxiliary transmission (C2). When the main transmissions (A) and (B) are operated to shift by the operation of the first artificial transmission (33), the auxiliary transmission (C2) is automatically shifted to the standard shift position in conjunction with this. A traveling speed change structure for a work vehicle, which is provided with an automatic return means for operating. 2. A main transmission (A), (B) capable of shifting in a plurality of stages and a forward / reverse switching device (C1) are arranged in series, and a standard shift position and a transmission ratio different from the standard shift position are provided. The auxiliary transmission (C2) provided with the temporary shift position is disposed below the forward side of the forward-reverse switching device (C1) and is manually operated. The main transmission (A),
(B) is provided with a first artificial speed changer (33) and a second artificial speed changer (52) that is operated manually to change the speed of the auxiliary transmission (C2). When the main transmissions (A) and (B) are operated to shift by the operation of the first artificial transmission (33), the auxiliary transmission (C2) is automatically shifted to the standard shift position in conjunction with this. A traveling speed change structure for a work vehicle, which is provided with an automatic return means for operating. 3. A standard transmission position, in which main transmissions (A), (B) capable of shifting in a plurality of stages, an auxiliary auxiliary transmission (D), and a forward / reverse switching device (C1) are arranged in series. And the auxiliary transmission (C2) provided with a temporary transmission position having a transmission ratio different from the standard transmission position, the forward / reverse switching device (C1).
Of the main transmission (A), which is placed on the lower side of the forward side of
(B) a first artificial transmission (33) for shifting, and a second artificial transmission (52) that is artificially operated to shift the auxiliary transmission (C2) and artificially operated. The third artificial transmission (43) for shifting the auxiliary auxiliary transmission (D) and the artificial switching operation tool for artificially operating the forward / reverse switching device (C1). (16) and when the main transmissions (A) and (B) are operated to shift by the operation of the first artificial transmission (33), or
When the auxiliary sub-transmission device (D) is shifted by the operation of the artificial transmission device (43), or when the forward / reverse switching device (C1) is switched by the operation of the artificial switching operation device (16). , The auxiliary transmission (C
A traveling speed change structure for a work vehicle, which is provided with an automatic return means for automatically changing the speed of 2) to a standard speed change position. 4. A predetermined number of gears (N) of two or more is set, and the main transmissions (A) and (B) are operated by the operation of the first artificial transmission (33) so that the number of predetermined gears (N) is changed. ) The automatic return means is configured to automatically shift the auxiliary transmission (C2) to the standard shift position in response to the above shift operation. Three
The traveling speed change structure for a work vehicle according to any one of the above. 5. When the main transmissions (A), (B) are shifted to a high speed side by the operation of the first artificial transmission (33), the auxiliary transmission (C2) is interlocked with this. The traveling speed change structure for a work vehicle according to any one of claims 1, 2 and 3, wherein the automatic return means is configured to automatically shift the vehicle to a standard speed change position. 6. When the main transmissions (A), (B) are shifted to a low speed side by the operation of the first artificial transmission (33), the auxiliary transmission (C2) is interlocked with this. The traveling speed change structure for a work vehicle according to any one of claims 1, 2 and 3, wherein the automatic return means is configured to automatically shift the vehicle to a standard speed change position. 7. The traveling speed change of the work vehicle according to claim 1, wherein the auxiliary speed change device (C2) has a temporary speed change position set to a lower speed side than a standard speed change position. Construction. 8. The transmission ratio difference between the standard transmission position and the temporary transmission position in the auxiliary transmission (C2) is transferred between the transmission positions in the main transmissions (A) and (B). The traveling speed change structure for a working vehicle according to any one of claims 1 to 7, wherein the difference is set to be smaller than the difference. 9. The operation switch (5) in which the first artificial transmission (33) is a manually operated gear shift lever (33), and the second artificial transmission (52) is artificially operated.
The traveling speed change structure for a work vehicle according to any one of claims 1 to 8, wherein the speed change lever (33) is provided with the operation switch (52). 10. The traveling speed change structure for a work vehicle according to any one of claims 1 to 9, further comprising a switching means (54) which is operable to switch the automatic return means between an activated state and an inoperative state. . 11. A display means (53) for displaying a shift state of the auxiliary transmission (C2) is provided.
The traveling speed change structure for a work vehicle according to any one of the above.