JP2003095127A - Transmission structure of work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the occurrence of such an inconvenience that a machine stops without turning when switching from a straight forward run to a turning run. SOLUTION: When a turning run in which one claw clutch 23 is switched to a transmission state from a straight forward run in which both right and left claw clutches 23 are switched to the transmission state is started, a friction clutch 29 is switched gradually from a connected state to a disconnected state according to the switching of one claw clutch 23 to a non-transmission state. When the turn running in which one claw clutch 23 is switched from a non- transmission state to the transmission state is terminated, the friction clutch 29 is switched gradually from the disconnected state to the connected state at a stage before one claw clutch 23 is switched to the transmission state. In the straight forward running state, the disconnected state of the friction clutch 29 is produced. When turning is started, the connected state of the friction clutch 29 is produced at a stage before one claw clutch 23 is switched from the transmission state to the non-transmission state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of connecting and disconnecting left and right meshing clutches, which engage and disengage transmission to the corresponding traveling device, and drive shafts of the left and right traveling devices in a transmission system for the left and right traveling devices. Equipped with a steering device having a friction clutch, and at the start of turning traveling in which one of the mesh clutches is switched to a non-transmission state from a straight traveling state in which the left and right mesh clutches are switched to a transmission state. When one of the mesh clutches is switched to the non-transmission state, the friction clutch is gradually switched from the connected state to the disengaged state, and one of the mesh clutches is switched from the non-transmission state to the transmission state. , The friction clutch is gradually changed from the disengaged state to the connected state before the one of the dog clutches is switched to the transmission state. Regarding transmission structure of the working machine that is configured to be Rikae.

[0002]

2. Description of the Related Art When the power transmission structure of a work machine is constructed as described above, at the start of turning traveling in which one of the meshing clutches is switched to a non-transmission state, one of the traveling devices whose transmission is disengaged by the corresponding meshing clutch is supported. The power from the other traveling device that continues to be transmitted by the meshing clutch is transmitted through the friction clutch, and the transmission through the friction clutch is gradually released. Even if the vehicle is in a weak state with a large running resistance, it is possible to avoid the inconvenience of sudden stop when one of the traveling devices is disengaged by the corresponding meshing clutch due to the running resistance. The transition to the turning traveling state can be smoothly performed.

Further, at the end of turning traveling in which one of the mesh clutches is switched from the non-transmission state to the transmission state, before the one mesh clutch is switched to the transmission state, the transmission is disengaged by the corresponding mesh clutch. The power from the other traveling device, which has been continuously transmitted by the corresponding meshing clutch, is gradually transmitted to the traveling device via the friction clutch. Since it is possible to avoid the sudden start of one of the traveling devices due to the sudden restart by the clutch, it is possible to smoothly perform the transition from the turning traveling state to the straight traveling state.

By the way, in the transmission structure of the working machine as described above, the friction clutch is conventionally maintained in the transmission state during straight traveling in which the left and right traveling devices are driven at a constant speed.

[0005]

However, according to the above-mentioned prior art, at the end of turning, one of the meshing clutches is switched from the non-transmission state to the transmission state by the transmission via the friction clutch. When the traveling device of 1 has reached the constant speed drive state, the meshing pawls of the one meshing clutch may rotate at a constant speed in a rotation phase that cannot mesh, and in this case, the one meshing clutch is transmitted. This causes an inconvenience that the state cannot be switched.

Further, even if the above-mentioned inconvenience occurs, since the straight traveling state in which the left and right traveling devices are driven at a constant speed is revealed by the transmission through the friction clutch, the operator is
At this stage, it is not possible to recognize that one of the dog clutches is still in the non-transmission state, so that the other dog clutch is switched from the straight traveling state to the non-transmission state to change the turning traveling state. When it appears, both the left and right meshing clutches are in a non-transmission state, which causes the inconvenience that the vehicle stops traveling without turning.

It is an object of the present invention to avoid the inconvenience of the inconvenience that the vehicle body stops traveling without turning when the traveling state is changed from the straight traveling state to appear.

[0008]

[Means for Solving the Problems] [Structure] In order to achieve the above object, in the invention according to claim 1 of the present invention, a transmission system for the left and right traveling devices is provided with a corresponding transmission to the traveling device. Equipped with a steering device provided with left and right meshing clutches that are intermittently connected and a friction clutch that allows the drive shafts of the left and right traveling devices to be intermittently connected, and the straight clutches in which both the left and right meshing clutches are switched to a transmission state At the start of turning traveling in which one of the mesh clutches is switched from the traveling state to the non-transmission state, the friction clutch is gradually switched from the connected state to the disengaged state with the switching of the one mesh clutch to the non-transmission state. , One of the dog clutches is switched to the power transmission state at the end of turning traveling in which the one clutch clutch is switched from the non-transmission state to the power transmission state. In the transmission structure of the working machine configured such that the friction clutch is gradually switched from the disengaged state to the engaged state in a stage before the start, the disengaged state of the friction clutch is revealed in the straight traveling state and the turning traveling is performed. At the start, the engagement state of the friction clutch is revealed before the one of the dog clutches is switched from the transmission state to the non-transmission state.

[Operation] According to the invention described in claim 1, at the start of the turning traveling in which one of the meshing clutches is switched to the non-transmission state, the friction is generated before the one of the meshing clutches is switched from the transmission state to the non-transmission state. Since the connected state of the clutch is revealed, the power from one traveling device whose transmission is interrupted by the one meshing clutch is frictioned by the power from the other traveling device whose transmission is continued by the other meshing clutch. Since the power is transmitted via the clutch and the power transmission via the friction clutch is gradually released, even if the running road surface is in a weak state where running resistance is large, Due to the running resistance, it is possible to prevent one of the running devices from suddenly stopping when the transmission is cut off by the corresponding meshing clutch.
The transition from the straight traveling state to the turning traveling state can be smoothly performed.

Further, at the end of turning traveling in which the one clutch clutch is switched from the non-transmission state to the transmission state, the transmission is discontinued by the one mesh clutch before the one clutch clutch is switched to the transmission state. The power from the other traveling device, which is being continuously transmitted by the other meshing clutch, is gradually transmitted to the traveling device via the friction clutch. It is possible to avoid a sudden start of one of the traveling devices due to the sudden restart by the clutch, and thus it is possible to smoothly transition from the turning traveling state to the straight traveling state.

Further, the disengaged state of the friction clutch is revealed in the straight traveling state, so that at the end of the turning traveling, one of the meshing clutches is engaged with the friction clutch until it is switched from the non-transmission state to the transmission state. Even if the left and right traveling devices reach a constant speed drive state due to the transmission, and the meshing claws of one meshing clutch rotate at a constant speed with the rotation phase incapable of meshing, the friction clutch is then removed from the connected state. By switching to the cutoff state, the left and right traveling devices are differentially operated, and a difference occurs in the rotational phase of the meshing pawls in the meshing clutch.
It becomes possible to switch one of the dog clutches from the non-power transmission state to the power transmission state, and as a result, the straight traveling state in which the left and right traveling devices are driven at a constant speed by the transmission through the left and right dog clutches is revealed. Will be able to.

That is, when the straight traveling state is switched from the turning traveling state to appear, the one traveling clutch is not engaged and the left and right traveling devices are driven at a constant speed by transmission through the friction clutch. Even if it appears, the disengaged state of the friction clutch appears and the non-transmission meshing clutch is switched to the transmission state in the straight traveling state, so that the transmission is not performed through the friction clutch but to the left and right. Since the left and right traveling devices will be driven at a constant speed by transmission via the double-engagement clutch, the left and right double-engaged clutches will be in the non-transmission state when switching from the straight traveling state to the turning traveling state and appearing. It is possible to prevent the inconvenience of the vehicle from stopping without turning.

[Effect] Therefore, the transition from the straight traveling state to the turning traveling state and the transition from the turning traveling state to the straight traveling state can be performed smoothly, and at the same time, the straight traveling state is switched to the turning traveling state to appear. In addition, it is possible to avoid the inconvenience that the left and right dog clutches are in the non-transmission state and the vehicle stops traveling without turning.

[Arrangement] In order to achieve the above object, in the invention according to claim 2 of the present invention, the left and right meshing clutches for connecting and disconnecting the transmission to the corresponding traveling device in the transmission system for the left and right traveling devices. And a steering device provided with a friction clutch that allows the drive shafts of the left and right traveling devices to be connected and disconnected, and the one of the left and right meshing clutches is switched from the straight traveling state to the transmission state. At the start of turning traveling in which the mesh clutch is switched to the non-transmission state, the friction clutch is gradually switched from the connected state to the disengaged state along with the switching of the one mesh clutch to the non-transmission state. At the end of the turning traveling in which the clutch is switched from the non-transmission state to the transmission state, at a stage before the one of the dog clutches is switched to the transmission state. In the transmission structure of the working machine configured to gradually switch the friction clutch from the disengaged state to the connected state, at the end of turning traveling, immediately before the one of the meshing clutches is switched from the non-transmission state to the transmission state, The friction clutch is configured to be temporarily switched from the connected state to the disconnected state.

[Operation] According to the second aspect of the present invention, at the start of turning traveling in which one of the meshing clutches is switched to the non-transmission state, friction is generated before the one of the meshing clutches is switched from the transmission state to the non-transmission state. Since the connected state of the clutch is revealed, the power from one traveling device whose transmission is interrupted by the one meshing clutch is frictioned by the power from the other traveling device whose transmission is continued by the other meshing clutch. Since the power is transmitted via the clutch and the power transmission via the friction clutch is gradually released, even if the running road surface is in a weak state where running resistance is large, Due to the running resistance, it is possible to prevent one of the running devices from suddenly stopping when the transmission is disengaged by the corresponding meshing clutch.
The transition from the straight traveling state to the turning traveling state can be smoothly performed.

Further, at the end of the turning traveling in which one of the mesh clutches is switched from the non-transmission state to the transmission state, the transmission is disengaged by the one mesh clutch before the one mesh clutch is switched to the transmission state. The power from the other traveling device, which is being continuously transmitted by the other meshing clutch, is gradually transmitted to the traveling device via the friction clutch. It is possible to avoid a sudden start of one of the traveling devices due to the sudden restart by the clutch, and thus it is possible to smoothly transition from the turning traveling state to the straight traveling state.

Moreover, at the end of the turning traveling, the left and right traveling devices reach the constant speed driving state by the transmission through the friction clutch until one of the dog clutches is switched from the non-transmission state to the transmission state. Even if the meshing claws of one meshing clutch rotate at a constant speed with the rotation phase incapable of meshing, the friction clutch is switched from the engaged state to the disengaged state immediately before the one meshing clutch switches to the transmission state. By doing so, the left and right traveling devices are differentially generated, and the rotational phase of the meshing pawls in the meshing clutch is different, so that one meshing clutch can be switched from the non-transmission state to the transmission state. As a result, a straight traveling state in which the left and right traveling devices are driven at a constant speed by transmission via the left and right meshing clutches can be revealed. To become.

That is, even when the straight traveling state is switched from the turning traveling state to appear, even if the straight traveling state in which the left and right traveling devices are driven at a constant speed by the transmission through the friction clutch appears temporarily. Immediately before one of the mesh clutches is switched from the non-transmission state to the transmission state, the friction clutch is temporarily switched from the connected state to the disengaged state, and the mesh clutch in the non-transmission state is switched to the transmission state.
Not only the transmission via the friction clutch but also the transmission via the left and right mesh clutches will drive the left and right traveling devices at a constant speed, so when switching from the straight traveling state to the turning traveling state, it appears. Thus, it is possible to avoid the inconvenience that the left and right dog clutches are in the non-transmission state and the vehicle stops traveling without turning.

[Effects] Therefore, the transition from the straight traveling state to the turning traveling state and the transition from the turning traveling state to the straight traveling state can be smoothly performed, and the straight traveling state can be switched to appear. In addition, it is possible to avoid the inconvenience that the left and right dog clutches are in the non-transmission state and the vehicle stops traveling without turning.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows the entire side surface of a self-removing combine, which is an example of a working machine. This combine is a pair of left and right crawlers, which is an example of a traveling device. To the front part of the traveling machine body 2 traveling by the operation of the traveling type traveling device 1, a harvesting and conveying device 3 for cutting the planted culm and conveying it to the rear is movably connected, and the traveling machine body 2 and the cutting and conveying device 3 are connected. The threshing device 4 that receives the slaughtered culms from the plant and performs the threshing / sorting process, and the grain tank 5 that stores the grain from the threshing device 4 are mounted, and the boarding operation unit is provided in front of the grain tank 5. 6 is formed.

Further, as shown in FIGS. 2 and 3, in this combine, the power from the engine 7 is transmitted to a hydrostatic continuously variable transmission 9 equipped in a transmission case 8 via a belt tension type main clutch 10. And the power after shifting by the hydrostatic continuously variable transmission 9 is transmitted to the left and right crawler-type traveling devices 1 via the transmission system 11 for traveling, which is installed in the lower half of the mission case 8. Thus, by operating a main gearshift lever (not shown) linked to the hydrostatic continuously variable transmission 9, switching between forward and backward movements and continuously variable gear shifting can be performed.

The hydrostatic continuously variable transmission 9 has an inwardly facing recess 13 formed in the left side wall 12 of the transmission case 8,
Axial type piston pump 14 and piston motor 1
5 and accommodates the piston pump 14 and the piston motor 1
The port block 18 in which the forward oil passage 16 and the reverse oil passage 17 that connect to 5 are formed is connected to the left side wall 12 to close the recess 13.

The transmission system 11 for traveling includes a gear type transmission device 19 to which the power from the hydrostatic stepless transmission device 9 is transmitted,
A sub gear shift lever (not shown) linked to a gear type transmission device 19 is configured by a hydraulic steering device 20 that steers the traveling machine body 2 by switching the operating state of the left and right crawler type traveling devices 1. By this operation, the power after shifting by the hydrostatic continuously variable transmission 9 can be shifted to high and low two stages.

At the upper part of the mission case 8, there is provided a work transmission system 22 for transmitting the power before shifting by the hydrostatic continuously variable transmission 9 to the cutting and conveying device 3 via the belt tension type cutting clutch 21. Has been done. The power transmission system 22 for work is operated by operating a work lever (not shown) linked to the work power transmission system 22. A low speed transmission state in which power from the engine 7 is driven at a work speed suitable for medium and low speed traveling, and a high speed transmission state are provided. It is configured so that it can be shifted into two levels, high and low, which is a high-speed transmission state in which the reaping and conveying device 3 is driven at a work speed suitable for traveling, and by expressing the driving state of the reaping and conveying device 3 suitable for the traveling speed. , The harvested grain culms can be cut and transported smoothly.

As shown in FIGS. 2 to 5, the steering device 20 includes
Crawler type traveling device 1 corresponding to the gear type transmission device 19
Left and right multi-disc brakes 2 for braking to the corresponding crawler type traveling device 1
4, corresponding meshing clutch 23 against the bias of spring 25
It is possible to connect the left and right hydraulic cylinders 26 that enable the cutting operation and the braking operation of the multi-plate brake 24, and the drive shafts 28 in the left and right crawler type traveling devices 1 against the bias of the springs 27. Hydraulic and multi-plate friction clutch 2
9 and so on.

The operating state of the steering device 20 can be switched by adjusting the flow rate of the mission oil that is pressure-fed by the hydraulic pump 30 as the hydraulic oil for the left and right hydraulic cylinders 26 and the friction clutch 29. The relief valve 32 and the first switching valve 3 which are provided in the steering oil passage 31.
3, the variable relief valve 34, and the operation of the second switching valve 35 can be controlled, and their operation control is performed.
The operation can be performed by operating an operation lever 36 linked to the first switching valve 33 and the variable relief valve 34. When the operating lever 36 is operated to the neutral position N, the first switching valve 33 stops the flow of the hydraulic oil from the hydraulic pump 30 and is in a neutral state in which the hydraulic oil from the left and right hydraulic cylinders 26 is discharged. While the operation lever 36 is switched and is located between the neutral position N and either of the left and right first turning positions L1, R1, the mission is performed without supplying the hydraulic oil from the hydraulic pump 30 to the left and right hydraulic cylinders 26. While returning to the case 8 as it is, the operating lever 36 is switched to the left or right straight traveling turning switching state in which the hydraulic oil is discharged from the left and right hydraulic cylinders 26, and the operating lever 36 is moved to the left or right first turning position L1, R1. From the second turning position L2 to the second turning position, the hydraulic pump 30 supplies the hydraulic oil to the hydraulic cylinder 26 corresponding to the operating direction. As well as permit, so that the switches on either the left or right turning state to allow discharge of the working oil from the hydraulic cylinder 26 against its operating direction. The variable relief valve 34 has a relief pressure of zero while the operating lever 36 is operated between the neutral position N and either the left or right first turning position L1, R1, and the left or right first turning position L1, R1. The relief pressure is set to increase as the operation is performed from R1 to the second turning position L2, R2 side. When the hydraulic pressure in the oil supply passage 37 extending from the hydraulic pump 30 to the first switching valve 33 exceeds a set value, the second switching valve 35 switches to a discharge state in which discharge of the hydraulic oil from the friction clutch 29 is allowed, and the second switching valve 35 is supplied. When the hydraulic pressure in the oil passage 37 becomes lower than the set value, the supply state is switched to allow the supply of the hydraulic oil to the friction clutch 29.

With this configuration, the steering device 20 has the first switching valve 3 when the operation lever 36 is in the neutral position N.
3 is displayed and the discharge state of the second switching valve 35 is displayed. As a result, hydraulic oil is discharged from the left and right hydraulic cylinders 26, and the left and right dog clutches 23 are released. Transmission state and left and right multi-plate brakes 24
The non-braking state of the left and right meshing clutches 23 is shown because the hydraulic oil is discharged from the friction clutch 29 and the disengaged state of the friction clutch 29 appears.
A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed is revealed by transmission via the.

When the operating lever 36 is operated from the neutral position N toward the first turning position L1 on the left side, the operating lever 36 moves from the neutral position N to the first turning position L1 on the left side. The first switching valve 33 switches to the straight left turn switching state and the second switching valve 35 switches to the supply state, whereby the left and right multi-disc brakes 24 are in the transmission state and the left and right multi-plate brakes 24 are in the non-braking state. While the operation is continued, the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29, and the friction clutch 29 is switched from the disengaged state to the connected state. Therefore, the operation lever 36 moves from the neutral position N to the first left side. When the vehicle starts to turn left until it is operated to the turning position L1, the left and right crawler type traveling devices 1 are driven at a constant speed by transmission via the left and right dog clutches 23 and the friction clutch 29. It is adapted to revealing the straight running state.

After that, when the operating lever 36 is operated to the first turning position L1 on the left side, the first switching valve 33 is switched to the left turning state, whereby the hydraulic oil from the hydraulic pump 30 is moved to the left side first. By being supplied to the hydraulic cylinder 26, the left hydraulic cylinder 26 operates until the first switching valve 33 and the variable relief valve 34 communicate with each other, and the left mesh clutch 23 switches from the transmission state to the non-transmission state. A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 appears, and thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero and the hydraulic pump 30 The hydraulic oil supplied to the left hydraulic cylinder 26 from the variable relief valve 34
Since it is discharged via the
Is maintained in the non-transmission state, the switching of the left multi-plate brake 24 from the non-braking state to the braking state is prevented, and the left dog clutch 23 is switched from the transmission state to the non-transmission state. The second switching valve 35 is switched to the discharge state by the operating pressure at the time of switching, and the hydraulic oil in the friction clutch 29 is gradually discharged and the friction clutch 29 is discharged.
Is gradually switched from the connected state to the disconnected state,
The crawler type traveling device 1 on the right side is driven while the left gentle turning state in which the crawler type traveling device 1 on the left side is driven is gradually switched to appear.

That is, when switching from the straight running state to the left gentle turning state and appearing, first, the right mesh clutch 2
The friction clutch 29 from the crawler type traveling device 1 on the right side where the transmission is continued by 3 to the crawler type traveling device 1 on the left side where the transmission is discontinued by the left meshing clutch 23.
Then, the transmission from the crawler type traveling device 1 on the right side via the friction clutch 29 to the crawler type traveling device 1 on the left side is gradually weakened, and the left crawler type traveling device is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the left crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large. It is possible to smoothly transition from the straight traveling state to the left gentle turning state.

After that, when the operating lever 36 is operated from the first turning position L1 on the left side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the left hydraulic cylinder 26, and the left multiple disc brake 24.
Is gradually switched to the braking state. Therefore, the left steep turning state in which the right crawler type traveling apparatus 1 is driven while the left crawler type traveling apparatus 1 is braked is changed from the left gentle turning state to the left crawler type traveling apparatus. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operating lever 36 is operated from the second turning position L2 on the left side toward the first turning position L1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the left side moves. The amount of hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position L1 on the left side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the left side is switched to the non-braking state. The switching to the state can be smoothly performed so that the braking on the left crawler type traveling device 1 is gradually weakened.

Next, when the operating lever 36 is operated from the first left turning position L1 toward the neutral position N, the operating lever 36 is moved from the left first turning position L1 to the neutral position N until the operating lever 36 reaches the neutral position N. , The first switching valve 33 switches to the straight forward left turn switching state, and the second switching valve 35 switches to the supply state, whereby the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29, and the friction clutch 29. Is gradually switched from the disconnected state to the connected state, so that transmission from the right crawler type traveling device 1 via the friction clutch 29 to the left crawler type traveling device 1 is started and the left crawler type traveling device 1 is While being driven, its transmission is gradually strengthened so that the driving speed of the left crawler type traveling device 1 is gradually increased, and thereafter the operation lever 36 is moved to the neutral position N. Once operated, switched to the second switching valve 35 is discharged state together with the first switching valve 33 is switched to the neutral state, thereby, the left side of the hydraulic cylinder 26
From the non-transmission state to the transmission state, and the friction clutch 29 switches to the disengagement state. Is smoothly transmitted to the straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right meshing clutches 23.

On the other hand, when the operation lever 36 is operated from the neutral position N toward the first turning position R1 on the right side, the operation lever 36 is operated from the neutral position N to the first turning position R1 on the right side. The first switching valve 33 is switched to the straight traveling right turning switching state and the second switching valve 35 is switched to the supply state, whereby the transmission state of the left and right dog clutches 23 and the non-braking state of the left and right multi-plate brakes 24. Is continued, the hydraulic oil from the hydraulic pump 30 is applied to the friction clutch 2
9 and the friction clutch 29 is switched from the disengaged state to the connected state, the right and left are started at the time of starting the right turn traveling until the operation lever 36 is operated from the neutral position N to the first turning position R1 on the right side. The left and right crawler type traveling devices 1 by transmission through the dog clutch 23 and the friction clutch 29 of
A straight running state in which the vehicle is driven at a constant speed is revealed.

After that, when the operating lever 36 is operated to the first turning position R1 on the right side, the first switching valve 33 is switched to the right turning state, whereby the hydraulic oil from the hydraulic pump 30 is turned to the right side. The hydraulic cylinder 26 of the right side is operated until the hydraulic cylinder 26 of the right side communicates with the first switching valve 33 and the variable relief valve 34, and the meshing clutch 23 of the right side is switched from the transmission state to the non-transmission state. , A linear traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 is displayed. Thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero, and the hydraulic pump The hydraulic oil supplied to the hydraulic cylinder 26 on the right side from 30 is the variable relief valve 34 as it is.
Since it is discharged through the
Is maintained in the non-transmission state, the switching of the right multi-plate brake 24 from the non-braking state to the braking state is prevented, and the right mesh clutch 23 is switched from the transmission state to the non-transmission state. The second switching valve 35 is switched to the discharge state by the operating pressure at the time of switching, and the hydraulic oil in the friction clutch 29 is gradually discharged and the friction clutch 29 is discharged.
Is gradually switched from the connected state to the disconnected state,
The left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is driven, and the right gentle turning state is gradually switched to appear.

That is, when the right running state is switched from the straight running state to the right side, the first dog clutch 2 on the left side is first shown.
The friction clutch 29 from the left crawler type traveling device 1 in which the transmission is continued by 3 to the right crawler type traveling device 1 in which the transmission is disengaged by the right meshing clutch 23.
Through the friction clutch 29, the transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 is gradually weakened, and the right crawler type traveling device 1 is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the right crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large, and thus, It is possible to smoothly transition from the straight traveling state to the right gentle turning state.

Thereafter, when the operating lever 36 is operated from the first turning position R1 on the right side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the hydraulic cylinder 26 on the right side, and the multiple disc brake 24 on the right side.
Is gradually switched to a braking state, so that the right crawler type traveling device from the right gentle turning state to the right crawler type traveling device in which the left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is braked. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operation lever 36 is operated from the second turning position L2 on the right side toward the first turning position R1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the right side changes. The amount of hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position R1 on the right side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the right side is switched to the non-braking state. Switching to the state can be smoothly performed so that braking on the right crawler type traveling device 1 is gradually weakened.

Next, when the operation lever 36 is operated from the first turning position R1 on the right side toward the neutral position N, the operation lever 36 is moved from the first turning position R1 on the right side to the neutral position N. , The first switching valve 33 switches to the straight forward right turn switching state, and the second switching valve 35 switches to the supply state, whereby the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29 and the friction clutch. Since 29 is gradually switched from the disconnected state to the connected state, transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 via the friction clutch 29 is started, and the right crawler type traveling device 1 is started. Is driven, and its transmission is gradually strengthened so that the driving speed of the crawler type traveling device 1 on the right side is gradually increased, and thereafter the operation lever 36 is moved to the neutral position N. Once operated, it switched to the second switching valve 35 is discharged state together with the first switching valve 33 is switched to the neutral state, thereby, the right hydraulic cylinder 26
From the non-transmission state to the transmission state of the meshing clutch 23 on the right side, and the friction clutch 29 switches to the disengagement state of the friction clutch 29. Is smoothly transmitted to the straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right meshing clutches 23.

Further, according to the above-mentioned structure, in the steering apparatus 20, at the end of the turning travel in which the operation lever 36 is operated to the neutral position N, either the left or right dog clutch 23 is switched from the non-transmission state to the transmission state. Until then, the left and right crawler type traveling devices 1 reach a constant speed drive state by the transmission via the friction clutch 29, and the meshing claws of the meshing clutch 23 that can be switched from the non-transmission state to the transmission state cannot rotate. Even if the phase is rotated at a constant speed, as the operation lever 36 is operated to the neutral position N, the discharge state of the second switching valve 35 appears and the friction clutch 29 is changed from the connected state. By switching to the disengaged state, the left and right crawler type traveling devices 1 are differentially operated, and the rotational phases of the engaging claws in the non-transmitting engaging clutch 23 become different. From the non-transmission state clutches 2
3 can be switched to a transmission state, and thus, when the operation lever 36 is operated to the neutral position N, straight traveling in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right meshing clutches 23. The state can be surely revealed.

Although not shown, the multi-plate brake 24 on the right side is linked to the brake pedal together with the main clutch 10. By depressing the brake pedal, the main clutch 10 moves from the engine 7 to the hydrostatic pressure. The transmission to the continuous variable transmission 9 can be cut off, and the multi-plate brake 24 can express the deceleration stop state in which the left and right crawler type traveling devices 1 are braked via the steering device 20, and the brakes thereof can be displayed. By holding the pedal in the operation position by depressing the pedal with the lock fitting, the parking state in which the multi-plate brake 24 functions as the parking brake can be revealed.

By the way, as shown in FIG. 5, the oil passage 38 for charging the hydrostatic continuously variable transmission 9 is connected to the oil passage portion of the steering oil passage 31 on the upstream side of the hydraulic pump 30. In this oil passage 38, a hydraulic pump 39 for charging, a check valve 40 for the forward oil passage 16,
A check valve 41 for the reverse oil passage 17, a neutral valve 42 for the forward oil passage 16, and a relief valve 43 are provided, and the return oil from the relief valve 43 is supplied to the hydrostatic continuously variable transmission 9 for cooling. It is supposed to be done.

[Second Embodiment] The second embodiment is different from the first embodiment in the operating state switching structure of the steering apparatus 20, and therefore the structure thereof will be described below.

As shown in FIG. 6, the operating state of the steering device 20 can be switched by adjusting the flow rate of the mission oil that is pumped by the hydraulic pump 30 as the hydraulic oil for the left and right hydraulic cylinders 26 and the friction clutch 29. The flow rate can be adjusted by adjusting the relief valve 32, the switching valve 44, the variable relief valve 34, and the pressure reducing valve 4 which are provided in the oil passage 31 for steering.
5 can be controlled by operating the operation lever 36 linked with the switching valve 44 and the variable relief valve 34. When the operation lever 36 is operated in the neutral region from the neutral position N to the left and right first turning positions L1 and R1, the switching valve 44 stops the flow of hydraulic oil from the hydraulic pump 30 and causes the left and right hydraulic pressures to stop. The operation lever 3 is switched to a neutral state in which the discharge of the hydraulic oil from the cylinder 26 is allowed.
6 is operated near the neutral position N, the hydraulic pump 3
The hydraulic oil from 0 is returned to the transmission case 8 as it is, and a depressurized state in which the hydraulic pressure in the oil supply passage 37 extending from the hydraulic pump 30 to the first switching valve 33 is lowered is temporarily displayed, and the operation lever 36 moves to the left and right. Any first turning position L
When operated within the turning operation region from 1, R1 to the second turning positions L2, R2, supply of hydraulic oil from the hydraulic pump 30 to the hydraulic cylinder 26 corresponding to the operating direction is allowed, and in the operating direction. It is adapted to be switched to either a left or right turning state that allows discharge of hydraulic oil from the opposite hydraulic cylinder 26. The variable relief valve 34 has a relief pressure of zero while the operating lever 36 is operated between the neutral position N and either the left or right first turning position L1, R1, and the left or right first turning position L1, R1. The relief pressure is set to increase as the operation is performed from R1 to the second turning position L2, R2 side.

With this configuration, in the steering device 20, the neutral state of the switching valve 44 appears when the operating lever 36 is located at the neutral position N, whereby the hydraulic oil from the left and right hydraulic cylinders 26 is released. Is discharged, the transmission state of the left and right dog clutches 23 and the left and right multi-plate brakes 2
The non-braking state of No. 4 appears, and the hydraulic clutch is supplied with hydraulic oil via the pressure reducing valve 45 to show the connected state of the friction clutch 29. A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed is revealed by transmission through the clutch 23 and the friction clutch 29.

When the operation lever 36 is operated from the neutral position N to the left first swivel position L1, the switching valve 44 is switched to the left swivel state, whereby the hydraulic oil from the hydraulic pump 30 is first supplied. By being supplied to the left hydraulic cylinder 26, the left hydraulic cylinder 26 operates until the switching valve 44 and the variable relief valve 34 communicate with each other, and the left mesh clutch 23 switches from the transmission state to the non-transmission state. A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 appears, and thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero and the hydraulic pump 30 The hydraulic oil supplied from the left side to the left side hydraulic cylinder 26 is discharged as it is through the variable relief valve 34. And the switching of the left multi-plate brake 24 from the non-braking state to the braking state is prevented, and the hydraulic oil in the friction clutch 29 is gradually discharged by the operation of the pressure reducing valve 45. As a result, the friction clutch 29 is gradually switched from the connected state to the disengaged state. Therefore, the left slowly turning state in which the right crawler type traveling device 1 is driven while the left crawler type traveling device 1 is driven is gradually switched. It is supposed to be released.

That is, when switching from the straight traveling state to the left gentle turning state and appearing, first, the right meshing clutch 2
The friction clutch 29 from the crawler type traveling device 1 on the right side where the transmission is continued by 3 to the crawler type traveling device 1 on the left side where the transmission is discontinued by the left meshing clutch 23.
Then, the transmission from the crawler type traveling device 1 on the right side via the friction clutch 29 to the crawler type traveling device 1 on the left side is gradually weakened, and the left crawler type traveling device is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the left crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large. It is possible to smoothly transition from the straight traveling state to the left gentle turning state.

Thereafter, when the operating lever 36 is operated from the first turning position L1 on the left side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the left hydraulic cylinder 26, and the left multiple disc brake 24.
Is gradually switched to the braking state. Therefore, the left steep turning state in which the right crawler type traveling apparatus 1 is driven while the left crawler type traveling apparatus 1 is braked is changed from the left gentle turning state to the left crawler type traveling apparatus. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operating lever 36 is operated from the second turning position L2 on the left side toward the first turning position L1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the left side moves. The amount of hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position L1 on the left side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the left side is switched to the non-braking state. The switching to the state can be smoothly performed so that the braking on the left crawler type traveling device 1 is gradually weakened.

Next, when the operating lever 36 is operated from the first left turning position L1 to the neutral position N, the switching valve 44 is switched to the neutral state, whereby the hydraulic oil is discharged from the left hydraulic cylinder 26. Left side mesh clutch 23
Is switched from the non-transmission state to the transmission state, and during the switching operation, the pressure reducing valve 45 is actuated in response to the switching valve 44 being switched to the neutral state. Supplied and friction clutch 29
Is gradually switched from the disconnected state to the connected state, so that transmission from the right crawler type traveling device 1 to the left side crawler type traveling device 1 via the friction clutch 29 is started and the left crawler type traveling device 1 is operated. As it is driven, its transmission is gradually strengthened and the drive speed of the left crawler type traveling device 1 is gradually increased. Therefore, the left and right dog clutches 23 and the friction clutch 2 are moved from the left gentle turning state.
The right and left crawler type traveling devices 1 can be smoothly switched to a straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed.

On the other hand, when the operating lever 36 is operated from the neutral position N to the first turning position R1 on the right side, the changeover valve 44 is switched to the right turning state, whereby the hydraulic oil from the hydraulic pump 30 is first sent. Is supplied to the right hydraulic cylinder 26, the right hydraulic cylinder 26 operates until the switching valve 44 and the variable relief valve 34 communicate with each other, and the right mesh clutch 23 switches from the transmission state to the non-transmission state. , A linear traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 is displayed. Thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero, and the hydraulic pump Since the hydraulic oil supplied from 30 to the hydraulic cylinder 26 on the right side is directly discharged via the variable relief valve 34, the mesh clutch 23 on the right side is in the non-transmission state. While being maintained, the right multi-plate brake 24 is prevented from being switched from the non-braking state to the braking state, and the pressure reducing valve 45 is actuated to gradually discharge the hydraulic oil in the friction clutch 29. The friction clutch 29 is gradually switched from the connected state to the disengaged state, so that the left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is driven, and the right slow turning state is gradually changed to appear. It is supposed to do.

That is, when the rightward turning state is switched from the straight traveling state to appear, the first dog clutch 2 on the left side is first.
The friction clutch 29 from the left crawler type traveling device 1 in which the transmission is continued by 3 to the right crawler type traveling device 1 in which the transmission is disengaged by the right meshing clutch 23.
Through the friction clutch 29, the transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 is gradually weakened, and the right crawler type traveling device 1 is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the right crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large, and thus, It is possible to smoothly transition from the straight traveling state to the right gentle turning state.

Thereafter, when the operating lever 36 is operated from the first turning position R1 on the right side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the hydraulic cylinder 26 on the right side, and the multiple disc brake 24 on the right side.
Is gradually switched to a braking state, so that the right crawler type traveling device from the right gentle turning state to the right crawler type traveling device in which the left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is braked. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operating lever 36 is operated from the second turning position L2 on the right side toward the first turning position R1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the right side moves. The amount of hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position R1 on the right side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the right side is switched to the non-braking state. Switching to the state can be smoothly performed so that braking on the right crawler type traveling device 1 is gradually weakened.

Next, when the operating lever 36 is operated from the first turning position R1 on the right side to the neutral position N, the switching valve 44 is switched to the neutral state, whereby the hydraulic oil is discharged from the hydraulic cylinder 26 on the right side. The right mesh clutch 23
Is switched from the non-transmission state to the transmission state, and during the switching operation, the pressure reducing valve 45 is actuated in response to the switching valve 44 being switched to the neutral state. Supplied and friction clutch 29
Is gradually switched from the disconnected state to the connected state, so that transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 via the friction clutch 29 is started and the right crawler type traveling device 1 is As it is driven, its transmission is gradually strengthened so that the drive speed of the right crawler type traveling device 1 is gradually increased.
The right and left crawler type traveling devices 1 can be smoothly switched to a straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed.

Further, according to the above-mentioned structure, in the steering apparatus 20, at the end of the turning traveling in which the operating lever 36 is operated to the neutral position N, either the left or right dog clutch 23 is switched from the non-transmission state to the transmission state. Until then, the left and right crawler type traveling devices 1 reach a constant speed drive state by the transmission via the friction clutch 29, and the meshing claws of the meshing clutch 23 that can be switched from the non-transmission state to the transmission state cannot rotate. Even if the phase is rotated at a constant speed, the depressurized state of the switching valve 44 is temporarily revealed as the operation lever 36 is operated in the vicinity of the neutral position N,
Due to the operation of the pressure reducing valve 45 accompanying this, the hydraulic oil in the friction clutch 29 is temporarily discharged, and the friction clutch 29 is switched from the connected state to the disconnected state. As a result, the rotational phases of the meshing pawls of the non-transmission meshing clutch 23 are different from each other, so that the non-transmission meshing clutch 23 can be switched to the transmission state.
When 6 is in the neutral position N, the straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right both-side meshing clutch 23 and the friction clutch 29 is surely revealed. You can do it.

[Other Embodiments] Other embodiments of the present invention will be listed below. (1) The work machine may be a carrot harvester, a radish harvester, or the like. (2) The steering device 20 may be configured so that only a gentle turning state can appear.

[Brief description of drawings]

1] Overall side view of combine

FIG. 2 is a schematic diagram showing a transmission structure of a combine.

FIG. 3 is a vertical sectional front view of the mission case.

FIG. 4 is a vertical sectional front view of a lower portion of a mission case showing a configuration of a steering device.

FIG. 5 is a hydraulic circuit diagram in the first embodiment.

FIG. 6 is a hydraulic circuit diagram in the second embodiment.

[Explanation of symbols]

1 traveling device 11 Transmission system 20 Steering device 23 mesh clutch 28 Drive shaft 29 Friction clutch

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[Procedure amendment]

[Submission date] February 12, 2002 (2002.2.1
2)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Power transmission structure of working machine

[Claims]

3. A transmission system for left and right traveling devices is supported.
The left and right meshing clutches that intermittently transmit power to the traveling device.
In transmission structure of the working machine equipped with a switch, to permit intermittent between the drive shaft in the left and right traveling devices
Equipped with a friction clutch,
One of the above from the straight traveling state switched to the transmission state
The turning traveling is open when the dog clutch is switched to the non-transmission state.
At the beginning, one of the dog clutches is in the non-transmission state.
The friction clutch is disconnected from the connected state when the
It is gradually switched to the disconnected state, and one of the meshing clutches
Turning that allows the switch to switch from the non-transmission state to the transmission state
At the end of the line, one of the dog clutches is in the transmission state.
The friction clutch is in the disengaged state before switching to
From the connection state to the connection state, and one of the mesh clutches is in the non-transmission state at the end of turning traveling.
Immediately before switching from the transmission state to the transmission state, the friction clutch
The operation to switch from the connected state to the disconnected state of the
The transmission structure of the work machine configured as follows.

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission structure for traveling, which is used for working machines such as combine harvesters, carrot harvesters, and radish harvesters.

[0002]

2. Description of the Related Art As a transmission structure for traveling used in a working machine, there is known a transmission system for the left and right traveling devices, which is provided with left and right dog clutches for cutting off the transmission to the corresponding traveling devices. .

[0003]

In the transmission structure described above, when the traveling road surface is in a soft state where the traveling resistance is large, when the traveling resistance causes one of the traveling devices to discontinue the transmission by the corresponding meshing clutch. The inconvenience of sudden stop may occur.

The main object of the present invention is to prevent the occurrence of the inconvenience of sudden stop when one of the traveling devices is disengaged by the corresponding meshing clutch when the traveling state is switched from the straight traveling state to appear. To be able to avoid.

[0005]

[Means for Solving the Problems] [Structure] In order to achieve the above object, in the invention according to claim 1 of the present invention, a transmission system for the left and right traveling devices is connected to the corresponding transmission device. In a transmission structure of a working machine equipped with intermittent left and right dog clutches, a friction clutch is provided that allows the drive shafts of the left and right traveling devices to be interrupted, and the left and right dog clutches are switched to a transmission state in a straight line. At the start of turning traveling in which one of the mesh clutches is switched from the traveling state to the non-transmission state, the friction clutch is gradually switched from the connected state to the disengaged state with the switching of the one mesh clutch to the non-transmission state. ,
At the end of turning traveling in which one of the mesh clutches is switched from the non-transmission state to the transmission state, at a stage before the one mesh clutch is switched to the transmission state, the friction clutch is gradually changed from the disengaged state to the connected state. It is configured to be switched.

[Operation] According to the invention described in claim 1, at the start of the turning traveling in which one of the meshing clutches is switched to the non-transmission state, friction is caused at a stage before the one of the meshing clutches is switched from the transmission state to the non-transmission state. Since the connected state of the clutch is revealed, the power from one traveling device whose transmission is interrupted by the one meshing clutch is frictioned by the power from the other traveling device whose transmission is continued by the other meshing clutch. Since the power is transmitted via the clutch and the power transmission via the friction clutch is gradually released, even if the running road surface is in a weak state where running resistance is large, Due to the running resistance, it is possible to prevent one of the running devices from suddenly stopping when the transmission is disengaged by the corresponding meshing clutch.
The transition from the straight traveling state to the turning traveling state can be smoothly performed.

Further, at the end of turning traveling in which one of the dog clutches is switched from the non-transmission state to the power transmission state, the transmission is disengaged by the one dog clutch before the one dog clutch is switched to the transmission state. The power from the other traveling device, which is being continuously transmitted by the other meshing clutch, is gradually transmitted to the traveling device via the friction clutch. It is possible to avoid a sudden start of one of the traveling devices due to the sudden restart by the clutch, and thus it is possible to smoothly transition from the turning traveling state to the straight traveling state.

[Effect] Therefore, the transition from the straight traveling state to the turning traveling state and the transition from the turning traveling state to the straight traveling state can be smoothly performed.

[Arrangement] In order to achieve the above object, in the invention according to claim 2 of the present invention, the left and right meshing clutches for connecting and disconnecting the transmission to the corresponding traveling device in the transmission system for the left and right traveling devices. In a transmission structure of a working machine equipped with, a friction clutch is provided that enables the drive shafts of the left and right traveling devices to be disengaged from each other, and one of the left and right meshing clutches is switched from a straight traveling state to a transmission state. At the start of turning traveling in which the mesh clutch is switched to the non-transmission state, the friction clutch is gradually switched from the connected state to the disengaged state along with the switching of the one mesh clutch to the non-transmission state. At the end of turning traveling, in which the clutch is switched from the non-transmission state to the transmission state, one of the mesh clutches is switched to the transmission state. In the previous step, the friction clutch is configured to be gradually switched from the disengaged state to the connected state, the disengaged state of the friction clutch is revealed in the straight traveling state, and one of the dog clutches is engaged at the start of turning traveling. It is configured such that the engaged state of the friction clutch is revealed before the transmission state is switched to the non-transmission state.

[Operation] According to the second aspect of the present invention, at the start of turning traveling in which one of the meshing clutches is switched to the non-transmission state, friction is generated before the one of the meshing clutches is switched from the transmission state to the non-transmission state. Since the connected state of the clutch is revealed, the power from one traveling device whose transmission is interrupted by the one meshing clutch is frictioned by the power from the other traveling device whose transmission is continued by the other meshing clutch. Since the power is transmitted via the clutch and the power transmission via the friction clutch is gradually released, even if the running road surface is in a weak state where running resistance is large, Due to the running resistance, it is possible to prevent one of the running devices from suddenly stopping when the transmission is disengaged by the corresponding meshing clutch.
The transition from the straight traveling state to the turning traveling state can be smoothly performed.

Further, at the end of the turning traveling in which one of the mesh clutches is switched from the non-transmission state to the transmission state, the transmission is disengaged by the one mesh clutch before the one mesh clutch is switched to the transmission state. The power from the other traveling device, which is being continuously transmitted by the other meshing clutch, is gradually transmitted to the traveling device via the friction clutch. It is possible to avoid a sudden start of one of the traveling devices due to the sudden restart by the clutch, and thus it is possible to smoothly transition from the turning traveling state to the straight traveling state.

In the power transmission structure of the working machine as described above, when the friction clutch is maintained in the transmission state during straight traveling in which the left and right traveling devices are driven at a constant speed, one of If the left and right traveling devices reach the constant speed drive state due to the transmission via the friction clutch before the mesh clutch is switched from the non-transmission state to the transmission state, the meshing claws of the one meshing clutch are engaged. It may rotate at a constant speed with the impossible rotation phase, and in this case, one of the dog clutches cannot be switched to the transmission state, which causes a disadvantage.

Further, even if the above-mentioned inconvenience occurs, since the straight traveling state in which the left and right traveling devices are driven at a constant speed is revealed by the transmission through the friction clutch, the operator is
At this stage, it is not possible to recognize that one of the dog clutches is still in the non-transmission state, so that the other dog clutch is switched from the straight traveling state to the non-transmission state to change the turning traveling state. When it appears, both the left and right meshing clutches will be in a non-transmission state, and the inconvenience will occur in which the vehicle will stop without turning.

If the disengaged state of the friction clutch is displayed in the straight traveling state, one meshing clutch is switched from the non-transmission state to the transmission state at the end of the turning traveling. Therefore, even if the left and right traveling devices reach a constant speed drive state due to the transmission via the friction clutch, and the meshing claws of one meshing clutch rotate at a constant speed in a rotation phase that cannot mesh, then, When the friction clutch is switched from the connected state to the disengaged state, the left and right traveling devices are differentially generated, and the rotation phase of the meshing claws in the meshing clutch becomes different. It becomes possible to switch from the transmission state to the transmission state, and as a result, straight traveling in which the left and right traveling devices are driven at a constant speed by transmission through the left and right mesh clutches. It is possible to revealing the state.

Further, when the straight traveling state is switched from the turning traveling state to appear, the one traveling clutch is not engaged, and the left and right traveling devices are driven at a constant speed by transmission through the friction clutch. Even if it appears, the disengaged state of the friction clutch appears and the non-transmission meshing clutch is switched to the transmission state in the straight traveling state, so that the transmission is not performed through the friction clutch but to the left and right. Since the left and right traveling devices will be driven at a constant speed by transmission via the double-engagement clutch, the left and right double-engaged clutches will be in the non-transmission state when switching from the straight traveling state to the turning traveling state and appearing. It is possible to avoid the inconvenience that the vehicle body stops traveling without turning.

[Effect] Therefore, the transition from the straight traveling state to the turning traveling state and the transition from the turning traveling state to the straight traveling state can be smoothly performed, and at the same time, the straight traveling state is switched and the turning traveling state appears. In addition, it is possible to avoid the inconvenience that the left and right dog clutches are in the non-transmission state and the vehicle stops traveling without turning.

[Structure] In order to achieve the above-mentioned object, in the invention according to claim 3 of the present invention, the left and right meshing clutches for connecting and disconnecting the transmission to the corresponding traveling device in the transmission system for the left and right traveling devices. In a transmission structure of a working machine equipped with, a friction clutch is provided that enables the drive shafts of the left and right traveling devices to be disengaged from each other, and one of the left and right meshing clutches is switched from a straight traveling state to a transmission state. At the start of turning traveling in which the mesh clutch is switched to the non-transmission state, the friction clutch is gradually switched from the connected state to the disengaged state along with the switching of the one mesh clutch to the non-transmission state. At the end of the turning run in which the clutch is switched from the non-transmission state to the transmission state, one of the mesh clutches is switched to the transmission state. In the previous step, the friction clutch is configured to be gradually switched from the disengaged state to the connected state, and at the end of the turning traveling, the one of the meshing clutches is immediately before being switched from the non-transmission state to the transmission state. It is configured to temporarily perform the switching operation from the connected state to the disconnected state.

[Operation] According to the third aspect of the present invention, at the start of turning traveling in which one of the meshing clutches is switched to the non-transmission state, friction is generated before the one of the meshing clutches is switched from the transmission state to the non-transmission state. Since the connected state of the clutch is revealed, the power from one traveling device whose transmission is interrupted by the one meshing clutch is frictioned by the power from the other traveling device whose transmission is continued by the other meshing clutch. Since the power is transmitted via the clutch and the power transmission via the friction clutch is gradually released, even if the running road surface is in a weak state where running resistance is large, Due to the running resistance, it is possible to prevent one of the running devices from suddenly stopping when the transmission is disengaged by the corresponding meshing clutch.
The transition from the straight traveling state to the turning traveling state can be smoothly performed.

Further, at the end of the turning traveling in which the one clutch clutch is switched from the non-transmission state to the transmission state, the transmission is disengaged by the one mesh clutch before the one clutch clutch is switched to the transmission state. The power from the other traveling device, which is being continuously transmitted by the other meshing clutch, is gradually transmitted to the traveling device via the friction clutch. It is possible to avoid a sudden start of one of the traveling devices due to the sudden restart by the clutch, and thus it is possible to smoothly transition from the turning traveling state to the straight traveling state.

In addition, at the end of the turning traveling, the left and right traveling devices reach the constant speed drive state by the transmission through the friction clutch until one of the dog clutches is switched from the non-transmission state to the transmission state. Even if the meshing claws of one meshing clutch rotate at a constant speed with the rotation phase incapable of meshing, the friction clutch is switched from the engaged state to the disengaged state immediately before the one meshing clutch switches to the transmission state. By doing so, the left and right traveling devices are differentially generated, and the rotational phase of the meshing pawls in the meshing clutch is different, so that one meshing clutch can be switched from the non-transmission state to the transmission state. As a result, a straight traveling state in which the left and right traveling devices are driven at a constant speed by transmission via the left and right meshing clutches can be revealed. To become.

That is, when the straight traveling state is switched from the turning traveling state to appear, even if the straight traveling state in which the left and right traveling devices are driven at a constant speed by transmission through the friction clutch appears temporarily. Immediately before one of the dog clutches is switched from the non-transmission state to the transmission state, the friction clutch is temporarily switched from the connected state to the disengaged state, and the non-transmission clutch clutch is switched to the transmission state.
Not only the transmission via the friction clutch but also the transmission via the left and right mesh clutches will drive the left and right traveling devices at a constant speed, so when switching from the straight traveling state to the turning traveling state, it appears. Thus, it is possible to avoid the inconvenience that the left and right dog clutches are in the non-transmission state and the vehicle stops traveling without turning.

[Effect] Therefore, when the transition from the straight traveling state to the turning traveling state and the transition from the turning traveling state to the straight traveling state can be performed smoothly, and when the straight traveling state is switched and the turning traveling state appears. In addition, it is possible to avoid the inconvenience that the left and right dog clutches are in the non-transmission state and the vehicle stops traveling without turning.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows the entire side surface of a self-removing combine, which is an example of a working machine. This combine is a pair of left and right crawlers, which is an example of a traveling device. To the front part of the traveling machine body 2 traveling by the operation of the traveling type traveling device 1, a harvesting and conveying device 3 for cutting the planted culm and conveying it to the rear is movably connected, and the traveling machine body 2 and the cutting and conveying device 3 are connected. The threshing device 4 that receives the slaughtered culms from the plant and performs the threshing / sorting process, and the grain tank 5 that stores the grain from the threshing device 4 are mounted, and the boarding operation unit is provided in front of the grain tank 5. 6 is formed.

Further, as shown in FIGS. 2 and 3, in this combine, the power from the engine 7 is transmitted to the hydrostatic continuously variable transmission 9 equipped in the transmission case 8 via the belt tension type main clutch 10. And the power after shifting by the hydrostatic continuously variable transmission 9 is transmitted to the left and right crawler-type traveling devices 1 via the transmission system 11 for traveling, which is installed in the lower half of the mission case 8. Thus, by operating a main gearshift lever (not shown) linked to the hydrostatic continuously variable transmission 9, switching between forward and backward movements and continuously variable gear shifting can be performed.

The hydrostatic continuously variable transmission 9 has an inwardly facing recess 13 formed in the left side wall 12 of the mission case 8,
Axial type piston pump 14 and piston motor 1
5 and accommodates the piston pump 14 and the piston motor 1
The port block 18 in which the forward oil passage 16 and the reverse oil passage 17 that connect to 5 are formed is connected to the left side wall 12 to close the recess 13.

The traveling transmission system 11 includes a gear type transmission device 19 to which the power from the hydrostatic continuously variable transmission device 9 is transmitted,
A sub gear shift lever (not shown) linked to a gear type transmission device 19 is configured by a hydraulic steering device 20 that steers the traveling machine body 2 by switching the operating state of the left and right crawler type traveling devices 1. By this operation, the power after shifting by the hydrostatic continuously variable transmission 9 can be shifted to high and low two stages.

At the upper part of the mission case 8, there is provided a work transmission system 22 for transmitting the power before shifting by the hydrostatic continuously variable transmission 9 to the reaping and conveying device 3 via the belt tension type reaping clutch 21. Has been done. The power transmission system 22 for work is operated by operating a work lever (not shown) linked to the work power transmission system 22. A low speed transmission state in which power from the engine 7 is driven at a work speed suitable for medium and low speed traveling, and a high speed transmission state are provided. It is configured so that it can be shifted into two levels, high and low, which is a high-speed transmission state in which the reaping and conveying device 3 is driven at a work speed suitable for traveling, and by expressing the driving state of the reaping and conveying device 3 suitable for the traveling speed. , The harvested grain culms can be cut and transported smoothly.

As shown in FIGS. 2 to 5, the steering device 20 includes
Crawler type traveling device 1 corresponding to the gear type transmission device 19
Left and right multi-disc brakes 2 for braking to the corresponding crawler type traveling device 1
4, corresponding meshing clutch 23 against the bias of spring 25
It is possible to connect the left and right hydraulic cylinders 26 that enable the cutting operation and the braking operation of the multi-plate brake 24, and the drive shafts 28 in the left and right crawler type traveling devices 1 against the bias of the springs 27. Hydraulic and multi-plate friction clutch 2
9 and so on.

The operating state of the steering device 20 can be switched by adjusting the flow rate of the transmission oil that is pressure-fed by the hydraulic pump 30 as the operating oil for the left and right hydraulic cylinders 26 and the friction clutch 29. The relief valve 32 and the first switching valve 3 which are provided in the steering oil passage 31.
3, the variable relief valve 34, and the operation of the second switching valve 35 can be controlled, and their operation control is performed.
The operation can be performed by operating an operation lever 36 linked to the first switching valve 33 and the variable relief valve 34. When the operating lever 36 is operated to the neutral position N, the first switching valve 33 stops the flow of the hydraulic oil from the hydraulic pump 30 and is in a neutral state in which the hydraulic oil from the left and right hydraulic cylinders 26 is discharged. While the operation lever 36 is switched and is located between the neutral position N and either of the left and right first turning positions L1, R1, the mission is performed without supplying the hydraulic oil from the hydraulic pump 30 to the left and right hydraulic cylinders 26. While returning to the case 8 as it is, the operating lever 36 is switched to the left or right straight traveling turning switching state in which the hydraulic oil is discharged from the left and right hydraulic cylinders 26, and the operating lever 36 is moved to the left or right first turning position L1, R1. From the second turning position L2 to the second turning position, the hydraulic pump 30 supplies the hydraulic oil to the hydraulic cylinder 26 corresponding to the operating direction. As well as permit, so that the switches on either the left or right turning state to allow discharge of the working oil from the hydraulic cylinder 26 against its operating direction. The variable relief valve 34 has a relief pressure of zero while the operating lever 36 is operated between the neutral position N and either the left or right first turning position L1, R1, and the left or right first turning position L1, R1. The relief pressure is set to increase as the operation is performed from R1 to the second turning position L2, R2 side. When the hydraulic pressure in the oil supply passage 37 extending from the hydraulic pump 30 to the first switching valve 33 exceeds a set value, the second switching valve 35 switches to a discharge state in which discharge of the hydraulic oil from the friction clutch 29 is allowed, and the second switching valve 35 is supplied. When the hydraulic pressure in the oil passage 37 becomes lower than the set value, the supply state is switched to allow the supply of the hydraulic oil to the friction clutch 29.

With this configuration, the steering device 20 has the first switching valve 3 when the operation lever 36 is in the neutral position N.
3 is displayed and the discharge state of the second switching valve 35 is displayed. As a result, hydraulic oil is discharged from the left and right hydraulic cylinders 26, and the left and right dog clutches 23 are released. Transmission state and left and right multi-plate brakes 24
The non-braking state of the left and right meshing clutches 23 is shown because the hydraulic oil is discharged from the friction clutch 29 and the disengaged state of the friction clutch 29 appears.
A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed is revealed by transmission via the.

When the operation lever 36 is operated from the neutral position N toward the left first turning position L1, the operation lever 36 is moved from the neutral position N to the left first turning position L1. The first switching valve 33 switches to the straight left turn switching state and the second switching valve 35 switches to the supply state, whereby the left and right multi-disc brakes 24 are in the transmission state and the left and right multi-plate brakes 24 are in the non-braking state. While the operation is continued, the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29, and the friction clutch 29 is switched from the disengaged state to the connected state. Therefore, the operation lever 36 moves from the neutral position N to the first left side. When the vehicle starts to turn left until it is operated to the turning position L1, the left and right crawler type traveling devices 1 are driven at a constant speed by transmission via the left and right dog clutches 23 and the friction clutch 29. It is adapted to revealing the straight running state.

After that, when the operating lever 36 is operated to the first turning position L1 on the left side, the first switching valve 33 is switched to the left turning state, whereby the hydraulic oil from the hydraulic pump 30 is moved to the left side first. By being supplied to the hydraulic cylinder 26, the left hydraulic cylinder 26 operates until the first switching valve 33 and the variable relief valve 34 communicate with each other, and the left mesh clutch 23 switches from the transmission state to the non-transmission state. A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 appears, and thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero, and the hydraulic pump 30 The hydraulic oil supplied to the left hydraulic cylinder 26 from the variable relief valve 34
Since it is discharged via the
Is maintained in the non-transmission state, the switching of the left multi-plate brake 24 from the non-braking state to the braking state is prevented, and the left dog clutch 23 is switched from the transmission state to the non-transmission state. The second switching valve 35 is switched to the discharge state by the operating pressure at the time of switching, and the hydraulic oil in the friction clutch 29 is gradually discharged and the friction clutch 29 is discharged.
Is gradually switched from the connected state to the disconnected state,
The crawler type traveling device 1 on the right side is driven while the left gentle turning state in which the crawler type traveling device 1 on the left side is driven is gradually switched to appear.

That is, when switching from the straight traveling state to the left gentle turning state and appearing, first, the right meshing clutch 2
The friction clutch 29 from the crawler type traveling device 1 on the right side where the transmission is continued by 3 to the crawler type traveling device 1 on the left side where the transmission is discontinued by the left meshing clutch 23.
Then, the transmission from the crawler type traveling device 1 on the right side via the friction clutch 29 to the crawler type traveling device 1 on the left side is gradually weakened, and the left crawler type traveling device is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the left crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large. It is possible to smoothly transition from the straight traveling state to the left gentle turning state.

Thereafter, when the operating lever 36 is operated from the left first turning position L1 toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the left hydraulic cylinder 26, and the left multiple disc brake 24.
Is gradually switched to the braking state. Therefore, the left steep turning state in which the right crawler type traveling apparatus 1 is driven while the left crawler type traveling apparatus 1 is braked is changed from the left gentle turning state to the left crawler type traveling apparatus. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operating lever 36 is operated from the second turning position L2 on the left side toward the first turning position L1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the left side moves. The hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position L1 on the left side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the left side is switched to the non-braking state. The switching to the state can be smoothly performed so that the braking on the left crawler type traveling device 1 is gradually weakened.

Next, when the operating lever 36 is operated from the first left turning position L1 toward the neutral position N, the operating lever 36 is moved from the left first turning position L1 to the neutral position N. , The first switching valve 33 switches to the straight forward left turn switching state, and the second switching valve 35 switches to the supply state, whereby the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29, and the friction clutch 29. Is gradually switched from the disconnected state to the connected state, so that transmission from the right crawler type traveling device 1 via the friction clutch 29 to the left crawler type traveling device 1 is started and the left crawler type traveling device 1 is While being driven, its transmission is gradually strengthened so that the driving speed of the left crawler type traveling device 1 is gradually increased, and thereafter the operation lever 36 is moved to the neutral position N. Once operated, switched to the second switching valve 35 is discharged state together with the first switching valve 33 is switched to the neutral state, thereby, the left side of the hydraulic cylinder 26
From the non-transmission state to the transmission state, and the friction clutch 29 switches to the disengagement state. Is smoothly transmitted to the straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right meshing clutches 23.

On the other hand, when the operating lever 36 is operated from the neutral position N toward the first turning position R1 on the right side, until the operating lever 36 reaches the first turning position R1 on the right side from the neutral position N, The first switching valve 33 is switched to the straight traveling right turning switching state and the second switching valve 35 is switched to the supply state, whereby the transmission state of the left and right dog clutches 23 and the non-braking state of the left and right multi-plate brakes 24. Is continued, the hydraulic oil from the hydraulic pump 30 is applied to the friction clutch 2
9 and the friction clutch 29 is switched from the disengaged state to the connected state, the right and left are started at the time of starting the right turn traveling until the operation lever 36 is operated from the neutral position N to the first turning position R1 on the right side. The left and right crawler type traveling devices 1 by transmission through the dog clutch 23 and the friction clutch 29 of
A straight running state in which the vehicle is driven at a constant speed is revealed.

After that, when the operating lever 36 is operated to the first turning position R1 on the right side, the first switching valve 33 is switched to the right turning state, whereby the hydraulic oil from the hydraulic pump 30 is first moved to the right side. The hydraulic cylinder 26 of the right side is operated until the hydraulic cylinder 26 of the right side communicates with the first switching valve 33 and the variable relief valve 34, and the meshing clutch 23 of the right side is switched from the transmission state to the non-transmission state. , A linear traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 is displayed. Thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero, and the hydraulic pump The hydraulic oil supplied from 30 to the hydraulic cylinder 26 on the right side is the variable relief valve 34 as it is.
Since it is discharged through the
Is maintained in the non-transmission state, the switching of the right multi-plate brake 24 from the non-braking state to the braking state is prevented, and the right mesh clutch 23 is switched from the transmission state to the non-transmission state. The second switching valve 35 is switched to the discharge state by the operating pressure at the time of switching, and the hydraulic oil in the friction clutch 29 is gradually discharged and the friction clutch 29 is discharged.
Is gradually switched from the connected state to the disconnected state,
The left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is driven, and the right gentle turning state is gradually switched to appear.

That is, when the straight traveling state is switched to the right gentle turning state and the state appears, first, the left mesh clutch 2
The friction clutch 29 from the left crawler type traveling device 1 in which the transmission is continued by 3 to the right crawler type traveling device 1 in which the transmission is disengaged by the right meshing clutch 23.
Through the friction clutch 29, the transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 is gradually weakened, and the right crawler type traveling device 1 is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the right crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large, and thus, It is possible to smoothly transition from the straight traveling state to the right gentle turning state.

Thereafter, when the operation lever 36 is operated from the first turning position R1 on the right side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the hydraulic cylinder 26 on the right side, and the multiple disc brake 24 on the right side.
Is gradually switched to a braking state, so that the right crawler type traveling device from the right gentle turning state to the right crawler type traveling device in which the left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is braked. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operation lever 36 is operated from the second turning position L2 on the right side toward the first turning position R1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the right side changes. The amount of hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position R1 on the right side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the right side is switched to the non-braking state. Switching to the state can be smoothly performed so that braking on the right crawler type traveling device 1 is gradually weakened.

Next, when the operation lever 36 is operated from the first turning position R1 on the right side toward the neutral position N, the operation lever 36 is moved from the first turning position R1 on the right side to the neutral position N. , The first switching valve 33 switches to the straight forward right turn switching state, and the second switching valve 35 switches to the supply state, whereby the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29 and the friction clutch. Since 29 is gradually switched from the disconnected state to the connected state, transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 via the friction clutch 29 is started, and the right crawler type traveling device 1 is started. Is driven, and its transmission is gradually strengthened so that the driving speed of the crawler type traveling device 1 on the right side is gradually increased, and thereafter the operation lever 36 is moved to the neutral position N. Once operated, it switched to the second switching valve 35 is discharged state together with the first switching valve 33 is switched to the neutral state, thereby, the right hydraulic cylinder 26
From the non-transmission state to the transmission state of the meshing clutch 23 on the right side, and the friction clutch 29 switches to the disengagement state of the friction clutch 29. Is smoothly transmitted to the straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right meshing clutches 23.

Further, according to the above-mentioned structure, in the steering apparatus 20, at the end of the turning traveling in which the operating lever 36 is operated to the neutral position N, either the left or right dog clutch 23 is switched from the non-transmission state to the transmission state. Until then, the left and right crawler type traveling devices 1 reach a constant speed drive state by the transmission via the friction clutch 29, and the meshing claws of the meshing clutch 23 that can be switched from the non-transmission state to the transmission state cannot rotate. Even if the phase is rotated at a constant speed, as the operation lever 36 is operated to the neutral position N, the discharge state of the second switching valve 35 appears and the friction clutch 29 is changed from the connected state. By switching to the disengaged state, the left and right crawler type traveling devices 1 are differentially operated, and the rotational phases of the engaging claws in the non-transmitting engaging clutch 23 become different. From the non-transmission state clutches 2
3 can be switched to a transmission state, and thus, when the operation lever 36 is operated to the neutral position N, straight traveling in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right meshing clutches 23. The state can be surely revealed.

Although not shown, the multi-plate brake 24 on the right side is linked to the brake pedal together with the main clutch 10. By depressing the brake pedal, the main clutch 10 moves from the engine 7 to the hydrostatic pressure. The transmission to the continuous variable transmission 9 can be interrupted, and the deceleration stop state in which the multi-plate brake 24 brakes the left and right crawler type traveling devices 1 via the steering device 20 can be revealed, and the brakes thereof can be displayed. By holding the pedal in the operation position by depressing the pedal with the lock fitting, the parking state in which the multi-plate brake 24 functions as the parking brake can be revealed.

By the way, as shown in FIG. 5, the oil passage 38 for charging the hydrostatic continuously variable transmission 9 is connected to the oil passage portion of the steering oil passage 31 above the hydraulic pump 30. In this oil passage 38, a hydraulic pump 39 for charging, a check valve 40 for the forward oil passage 16,
A check valve 41 for the reverse oil passage 17, a neutral valve 42 for the forward oil passage 16, and a relief valve 43 are provided, and the return oil from the relief valve 43 is supplied to the hydrostatic continuously variable transmission 9 for cooling. It is supposed to be done.

[Second Embodiment] Since the second embodiment is different from the first embodiment in the operating state switching structure of the steering device 20, the structure will be described below.

As shown in FIG. 6, the operating state of the steering apparatus 20 can be switched by adjusting the flow rate of the mission oil pumped by the hydraulic pump 30 as the hydraulic oil for the left and right hydraulic cylinders 26 and the friction clutch 29. The flow rate can be adjusted by adjusting the relief valve 32, the switching valve 44, the variable relief valve 34, and the pressure reducing valve 4 which are provided in the oil passage 31 for steering.
5 can be controlled by operating the operation lever 36 linked with the switching valve 44 and the variable relief valve 34. When the operation lever 36 is operated in the neutral region from the neutral position N to the left and right first turning positions L1 and R1, the switching valve 44 stops the flow of hydraulic oil from the hydraulic pump 30 and causes the left and right hydraulic pressures to stop. The operation lever 3 is switched to a neutral state in which the discharge of the hydraulic oil from the cylinder 26 is allowed.
6 is operated near the neutral position N, the hydraulic pump 3
The hydraulic oil from 0 is returned to the transmission case 8 as it is, and a depressurized state in which the hydraulic pressure in the oil supply passage 37 extending from the hydraulic pump 30 to the first switching valve 33 is lowered is temporarily displayed, and the operation lever 36 moves to the left and right. Any first turning position L
When operated within the turning operation region from 1, R1 to the second turning positions L2, R2, supply of hydraulic oil from the hydraulic pump 30 to the hydraulic cylinder 26 corresponding to the operating direction is allowed, and in the operating direction. It is adapted to be switched to either a left or right turning state that allows discharge of hydraulic oil from the opposite hydraulic cylinder 26. The variable relief valve 34 has a relief pressure of zero while the operating lever 36 is operated between the neutral position N and either the left or right first turning position L1, R1, and the left or right first turning position L1, R1. The relief pressure is set to increase as the operation is performed from R1 to the second turning position L2, R2 side.

With this configuration, in the steering device 20, the neutral state of the switching valve 44 appears when the operating lever 36 is located at the neutral position N, and accordingly, the hydraulic oil is supplied from the left and right hydraulic cylinders 26. Is discharged, the transmission state of the left and right dog clutches 23 and the left and right multi-plate brakes 2
The non-braking state of No. 4 appears, and the hydraulic clutch is supplied with hydraulic oil via the pressure reducing valve 45 to show the connected state of the friction clutch 29. A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed is revealed by transmission through the clutch 23 and the friction clutch 29.

When the operating lever 36 is operated from the neutral position N to the left first swiveling position L1, the switching valve 44 is switched to the left swiveling state, whereby the hydraulic oil from the hydraulic pump 30 is first supplied. By being supplied to the left hydraulic cylinder 26, the left hydraulic cylinder 26 operates until the switching valve 44 and the variable relief valve 34 communicate with each other, and the left mesh clutch 23 switches from the transmission state to the non-transmission state. A straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 appears, and thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero and the hydraulic pump 30 The hydraulic oil supplied from the left side to the left side hydraulic cylinder 26 is discharged as it is through the variable relief valve 34. And the switching of the left multi-plate brake 24 from the non-braking state to the braking state is prevented, and the hydraulic oil in the friction clutch 29 is gradually discharged by the operation of the pressure reducing valve 45. As a result, the friction clutch 29 is gradually switched from the connected state to the disengaged state. Therefore, the left slowly turning state in which the right crawler type traveling device 1 is driven while the left crawler type traveling device 1 is driven is gradually switched. It is supposed to be released.

That is, when switching from the straight traveling state to the left gentle turning state and appearing, first, the right meshing clutch 2
The friction clutch 29 from the crawler type traveling device 1 on the right side where the transmission is continued by 3 to the crawler type traveling device 1 on the left side where the transmission is discontinued by the left meshing clutch 23.
Then, the transmission from the crawler type traveling device 1 on the right side via the friction clutch 29 to the crawler type traveling device 1 on the left side is gradually weakened, and the left crawler type traveling device is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the left crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large. It is possible to smoothly transition from the straight traveling state to the left gentle turning state.

After that, when the operating lever 36 is operated from the first turning position L1 on the left side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the left hydraulic cylinder 26, and the left multiple disc brake 24.
Is gradually switched to the braking state. Therefore, the left steep turning state in which the right crawler type traveling apparatus 1 is driven while the left crawler type traveling apparatus 1 is braked is changed from the left gentle turning state to the left crawler type traveling apparatus. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operation lever 36 is operated from the second turning position L2 on the left side toward the first turning position L1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the left side moves. The hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position L1 on the left side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the left side is switched to the non-braking state. The switching to the state can be smoothly performed so that the braking on the left crawler type traveling device 1 is gradually weakened.

Next, when the operating lever 36 is operated from the first left turning position L1 to the neutral position N, the switching valve 44 is switched to the neutral state, whereby the hydraulic oil is discharged from the left hydraulic cylinder 26. Left side mesh clutch 23
Is switched from the non-transmission state to the transmission state, and during the switching operation, the pressure reducing valve 45 is actuated in response to the switching valve 44 being switched to the neutral state. Supplied and friction clutch 29
Is gradually switched from the disconnected state to the connected state, so that transmission from the right crawler type traveling device 1 to the left side crawler type traveling device 1 via the friction clutch 29 is started and the left crawler type traveling device 1 is operated. As it is driven, its transmission is gradually strengthened and the drive speed of the left crawler type traveling device 1 is gradually increased. Therefore, the left and right dog clutches 23 and the friction clutch 2 are moved from the left gentle turning state.
The right and left crawler type traveling devices 1 can be smoothly switched to a straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed.

On the other hand, when the operating lever 36 is operated from the neutral position N to the first turning position R1 on the right side, the switching valve 44 is switched to the right turning state, whereby the hydraulic oil from the hydraulic pump 30 is first sent. Is supplied to the right hydraulic cylinder 26, the right hydraulic cylinder 26 operates until the switching valve 44 and the variable relief valve 34 communicate with each other, and the right mesh clutch 23 switches from the transmission state to the non-transmission state. , A linear traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed only by transmission via the friction clutch 29 is displayed. Thereafter, in this operating position, the relief pressure of the variable relief valve 34 is zero, and the hydraulic pump Since the hydraulic oil supplied from 30 to the hydraulic cylinder 26 on the right side is directly discharged via the variable relief valve 34, the mesh clutch 23 on the right side is in the non-transmission state. While being maintained, the right multi-plate brake 24 is prevented from being switched from the non-braking state to the braking state, and the pressure reducing valve 45 is actuated to gradually discharge the hydraulic oil in the friction clutch 29. The friction clutch 29 is gradually switched from the connected state to the disengaged state, so that the left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is driven, and the right slow turning state is gradually changed to appear. It is supposed to do.

That is, when the rightward turning state is switched from the straight traveling state to appear, first, the left dog clutch 2 is moved.
The friction clutch 29 from the left crawler type traveling device 1 in which the transmission is continued by 3 to the right crawler type traveling device 1 in which the transmission is disengaged by the right meshing clutch 23.
Through the friction clutch 29, the transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 is gradually weakened, and the right crawler type traveling device 1 is gradually transmitted. Since the traveling device 1 is driven, the driving speed of the right crawler type traveling device 1 can be gradually reduced even when the traveling road surface is in a weak state where the traveling resistance is large, and thus, It is possible to smoothly transition from the straight traveling state to the right gentle turning state.

Thereafter, when the operating lever 36 is operated from the first turning position R1 on the right side toward the second turning position L2,
The larger the operation amount, the larger the relief pressure of the variable relief valve 34, the larger the amount of hydraulic oil supplied to the hydraulic cylinder 26 on the right side, and the multiple disc brake 24 on the right side.
Is gradually switched to a braking state, so that the right crawler type traveling device from the right gentle turning state to the right crawler type traveling device in which the left crawler type traveling device 1 is driven while the right crawler type traveling device 1 is braked. It is possible to smoothly appear in a state in which the braking for 1 gradually increases.

On the contrary, when the operation lever 36 is operated from the second turning position L2 on the right side toward the first turning position R1, the relief pressure of the variable relief valve 34 decreases as the operation amount increases, and the right side changes. The hydraulic oil discharged from the hydraulic cylinder 26 of the
Braking gradually weakens and then the operating lever 36
Is operated to the first turning position R1 on the right side, the relief pressure of the variable relief valve 34 becomes zero and the multi-plate brake 24 on the right side is switched to the non-braking state. Switching to the state can be smoothly performed so that braking on the right crawler type traveling device 1 is gradually weakened.

Next, when the operation lever 36 is operated from the first turning position R1 on the right side to the neutral position N, the switching valve 44 is switched to the neutral state, whereby the hydraulic oil is discharged from the hydraulic cylinder 26 on the right side. The right mesh clutch 23
Is switched from the non-transmission state to the transmission state, and during the switching operation, the pressure reducing valve 45 is actuated in response to the switching valve 44 being switched to the neutral state. Supplied and friction clutch 29
Is gradually switched from the disconnected state to the connected state, so that transmission from the left crawler type traveling device 1 to the right crawler type traveling device 1 via the friction clutch 29 is started and the right crawler type traveling device 1 is As it is driven, its transmission is gradually strengthened so that the drive speed of the right crawler type traveling device 1 is gradually increased.
The right and left crawler type traveling devices 1 can be smoothly switched to a straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed.

Further, according to the above-described structure, in the steering apparatus 20, at the end of the turning traveling in which the operating lever 36 is operated to the neutral position N, either the left or right dog clutch 23 is switched from the non-transmission state to the transmission state. Until then, the left and right crawler type traveling devices 1 reach a constant speed drive state by the transmission via the friction clutch 29, and the meshing claws of the meshing clutch 23 that can be switched from the non-transmission state to the transmission state cannot rotate. Even if the phase is rotated at a constant speed, the depressurized state of the switching valve 44 is temporarily revealed as the operation lever 36 is operated in the vicinity of the neutral position N,
Due to the operation of the pressure reducing valve 45 accompanying this, the hydraulic oil in the friction clutch 29 is temporarily discharged, and the friction clutch 29 is switched from the connected state to the disconnected state. As a result, the rotational phases of the meshing pawls of the non-transmission meshing clutch 23 are different from each other, so that the non-transmission meshing clutch 23 can be switched to the transmission state.
When 6 is in the neutral position N, the straight traveling state in which the left and right crawler type traveling devices 1 are driven at a constant speed by transmission through the left and right both-side meshing clutch 23 and the friction clutch 29 is surely revealed. You can do it.

[Other Embodiments] Other embodiments of the present invention will be listed below. (1) The work machine may be a carrot harvester, a radish harvester, or the like. (2) The steering device 20 may be configured so that only a gentle turning state can appear.

[Brief description of drawings]

1] Overall side view of combine

FIG. 2 is a schematic diagram showing a transmission structure of a combine.

FIG. 3 is a vertical sectional front view of the mission case.

FIG. 4 is a vertical sectional front view of a lower portion of a mission case showing a configuration of a steering device.

FIG. 5 is a hydraulic circuit diagram in the first embodiment.

FIG. 6 is a hydraulic circuit diagram in the second embodiment.

[Explanation of symbols] 1 traveling device 11 Transmission system 20 Steering device 23 mesh clutch 28 Drive shaft 29 Friction clutch

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3D052 AA02 AA04 BB01 BB08 CC02                       DD04 EE01 JJ12 JJ14 JJ20                 3J057 AA03 BB01 BB04 FF01 FF10                       FF12 FF15 FF17 GA49 HH05                       JJ01

Claims (2)

[Claims] 1. A transmission system for the left and right traveling devices includes a left and right meshing clutch that engages and disengages transmission to the corresponding traveling device, and a friction clutch that enables engagement between drive shafts of the left and right traveling devices. Equipped with the equipped steering device,
At the start of the turning traveling in which one of the dog clutches is switched to the non-transmission state from the straight traveling state in which the left and right dog clutches are switched to the transmission state, one of the dog clutches is switched to the non-transmission state. The friction clutch is gradually switched from the connected state to the disengaged state, and one of the mesh clutches is switched from the non-transmission state to the transmission state. In stages,
A transmission structure of a work machine configured to gradually switch the friction clutch from a disengaged state to a connected state, wherein the disengaged state of the friction clutch is revealed in the straight traveling state, and one of At the stage before the dog clutch is switched from the transmission state to the non-transmission state,
A power transmission structure for a working machine configured to show a connection state of the friction clutch. 2. A transmission system for the left and right traveling devices includes a left and right meshing clutch that engages and disengages transmission to the corresponding traveling device, and a friction clutch that enables engagement between drive shafts of the left and right traveling devices. Equipped with the equipped steering device,
At the start of the turning traveling in which one of the dog clutches is switched to the non-transmission state from the straight traveling state in which the left and right dog clutches are switched to the transmission state, one of the dog clutches is switched to the non-transmission state. The friction clutch is gradually switched from the connected state to the disengaged state, and one of the mesh clutches is switched from the non-transmission state to the transmission state. In stages,
A transmission structure for a working machine configured such that the friction clutch is gradually switched from a disengaged state to a connected state, immediately before one of the mesh clutches is switched from a non-transmission state to a transmission state at the end of turning traveling. And a transmission structure for a working machine configured to temporarily perform a switching operation from the connected state to the disconnected state of the friction clutch.