KR20030026199A - Working vehicle - Google Patents

Abstract

PURPOSE: 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. CONSTITUTION: 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

WORKING VEHICLE}

The present invention relates to work machines such as combines, ginseng harvesters, waterless harvesters, and the like, and more particularly, to a traveling transmission structure used for such work machines.

As a driving transmission structure used for a work machine, it is known that the transmission system for the left and right traveling apparatuses (for example, a crawler, a vehicle, etc.) is provided with the left and right engagement clutch which interrupts the transmission to the corresponding traveling apparatus. .

In the above-mentioned transmission structure, when the state of the traveling road surface is a weak state with a large running resistance, a disadvantage arises in that the traveling resistance suddenly stops when power is interrupted by the corresponding engagement clutch by one traveling device.

Thus, the main object of the present invention is to certainly avoid the occurrence of the disadvantage of sudden stop when power is interrupted by the corresponding engagement clutch when one traveling device is switched by turning in the straight running state. It is to provide a work machine having a transmission structure configured to be.

1 is an overall side view of a combine;

2 is a schematic diagram showing a rolling configuration of a combine;

3 is a longitudinal sectional front view of the mission case;

4 is a longitudinal sectional front view of the lower part of the mission case showing the configuration of the steering apparatus;

5 is a hydraulic circuit diagram according to a first embodiment;

6 is a hydraulic circuit diagram according to a second embodiment.

In order to achieve the above object, the work machine according to the present invention includes a left and right traveling device, a left and right engagement clutch which is installed in an electric system for the left and right traveling devices, and blocks or connects power to a corresponding traveling device. As a work machine which is provided with respect to the left and right traveling devices, and has a left and right drive shaft for driving a corresponding traveling device,

When the left and right engagement clutches are switched to the electric state, the straight running state is displayed, and at the start of turning driving, one of the engagement clutches is switched to the non-motor state in the straight driving state, and at the end of the turning driving, In a work machine in which the engagement clutch is configured to switch from a non-driven state to an electric state,

A friction clutch 29 capable of interrupting and connecting power transmission between the drive shafts on the left and right sides is provided.

This friction clutch

At the start of the turning run, the one-to-one clutch is gradually switched from the connected state to the disconnected state in accordance with the switching to the non-driven state.

At the end of the turning run, the one engagement clutch is configured to be gradually switched from the disconnected state to the connected state before being switched to the electric state.

In addition, the said "one engagement clutch" which switches to the electric state from a non-electrical state at the time of turning is an engagement clutch of the side located in the inside of a turning. Therefore, the engagement clutch on the left side of the traveling body at the time of left turn, and the engagement clutch on the right side of the traveling body at the time of priority turn correspond to the "one engagement clutch".

With such a configuration, first, at the start of the turning drive in which one engagement clutch is switched to the non-electric state, the connection state of the friction clutch is shown in the stage before the one engagement clutch is switched from the electric state to the non-electric state. The power from the other traveling device in which transmission is continued by the other engagement clutch is transmitted to the traveling device in which the transmission is cut off by the one engagement clutch through the friction clutch, and such friction Transmission through the clutch is to be released slowly. From this, for example, even if the state of the traveling road surface is in a weak state with a large running resistance, the running resistance can avoid sudden stop when the driving device is cut off by the corresponding engagement clutch. Therefore, the transition from the straight driving state to the turning driving state is smoothly performed.

Next, at the end of the turning drive in which the one engagement clutch is switched from the non-driven state to the electric state, one traveling device whose electric power is cut off by the one engagement clutch before the one engagement clutch is switched to the electric state. Then, the power from the other traveling device in which transmission continues by the other engagement clutch is gradually transmitted through the friction clutch. From this, sudden start and stop of one traveling device due to sudden restart of the transmission to one traveling device by the corresponding engagement clutch can be avoided, so that the transition from the turning driving state to the straight running state is smoothly performed. It is done.

Therefore, in the work machine according to the present invention, the above-mentioned disadvantages are also reliably avoided and reliably avoided for the transition from the straight running state to the turning driving state, and also for the transition from the turning driving state to the straight running state. Operation and linear return operation can be performed smoothly.

In addition to the above configuration, the friction clutch is in a blocking state in the straight traveling state, and at the start of the turning driving, the friction clutch is in a connected state before the one engagement clutch is switched from the electric state to the non-electric state. If it is comprised, it is advantageous at the following points.

In the work machine as described above, the left and right traveling apparatuses have a transmission structure configured to hold the friction clutch in an electric state when driving in a constant speed driving. In such a configuration, at the end of the turning run, when the left and right traveling devices reach the constant speed drive state by the transmission through the friction clutch between the one-way clutch and the non-driven state to the electric state. The engagement clicks of one of the engagement clutches may rotate at a constant speed as they are in a non-engageable rotational phase. In this case, there is a disadvantage in that the engagement clutch cannot be switched to an electric state.

Moreover, even if the above-mentioned disadvantages occur, since the straight driving state in which the left and right traveling devices are driven at constant speed is displayed by the electric transmission through the friction clutch, the operator is responsible for ensuring that one of the engagement clutches is in the non-driven state at this stage. Can not confirm. For this reason, when switching the other engagement clutch from the electric state to the non-drive state in the straight driving state to indicate the turning driving state, the left and right engagement clutches become the non-motor state, and there is a fear that the vehicle will not stop running without turning. have.

Advantageously, in the present invention, since it is configured to show the blocking state of the friction clutch in the straight driving state, at the end of the turning driving, for example, the above-described situation (until one engagement clutch is switched from the non-electric state to the electric state). Even if the right and left traveling devices reach the constant speed driving state by the transmission through the friction clutch, and the engagement clicks of one of the engagement clutches are made to rotate at the same speed as the non-engaging rotation phase), thereafter, The friction clutch is transferred from the connected state to the disconnected state. Since the friction clutch is switched to the shut-off state, the left and right traveling devices are differential, and a difference in the rotational phases between the engagement clicks in the engagement clutch is possible, so that one engagement clutch can be switched from the non-driven state to the electric state. do. As a result, it is possible to reliably indicate the straight traveling state in which the left and right traveling devices are driven at constant speed by the electric transmission through the left and right engagement clutches.

Furthermore, for example, when switching from the turning driving state to the straight driving state, even if one of the engagement clutches is not engaged, the straight driving state in which the left and right traveling devices are driven at the same speed by the friction clutch is temporarily displayed. In the state, the state of the friction clutch is cut off, and the non-driven engagement clutch is switched to the electric state. When switching in this way, there is no transmission through the friction clutch thereafter, and the left and right traveling devices are driven at constant speed by the transmission through the friction clutches on the left and right sides. The friction clutch is in a non-driven state so that it is possible to surely avoid the occurrence of the disadvantage that the vehicle stops running without turning.

Therefore, it is possible to more reliably avoid the occurrence of the above-mentioned disadvantages, particularly when the turning driving state is switched and displayed in the straight driving state.

Furthermore, if the friction clutch is configured to temporarily switch operation from the connected state to the disconnected state immediately before the one engagement clutch is switched from the non-driven state to the electric state at the end of the turning run, the following points will be given. It is advantageous.

According to this configuration, at the end of turning driving, for example, the driving device on the left and right reaches the constant speed driving state by the transmission through the friction clutch, for example, until one of the engagement clutches is switched from the non-driven state to the electric state. . Even if the engagement clicks of the one engagement clutches are rotated at constant speed as they are in a non-engaged rotational phase, the friction clutch is operated from the connected state to the disconnected state just before the one engagement clutch is switched to the electric state, thereby allowing the left and right traveling devices to In the differential clutch, a difference occurs in rotational phases between the engaging clicks. As a result, one of the engagement clutches is switched from the non-driven state to the electric state, and as a result, it is possible to represent a straight running state in which the left and right traveling devices are driven at constant speed by electric transmission through the left and right engagement clutches.

That is, when the transition from the turning driving state to the straight driving state is indicated, even if the straight driving state in which the left and right traveling devices are driven at constant speed by electric transmission through the friction clutch is temporarily indicated, one of the engagement clutches is switched from the non-drive state to the electric state. Immediately before the friction clutch is engaged, the clutch clutch is temporarily switched from the connected state to the disconnected state, and the non-driven engagement clutch is transferred to the electric state, and not only through the friction clutch but also through the left and right engagement clutches. Since the traveling device is designed to be driven at constant speed, the left and right interlocking clutches are in the non-driven state when switching from the straight driving state to the turning driving state, thereby avoiding the disadvantage of stopping the vehicle without turning. do.

Therefore, in particular, the occurrence of the above-described disadvantages when switching the turning driving state in the straight driving state can be more surely avoided.

In the case where the friction clutch is hydraulic, the structure in which the friction clutch is temporarily switched from the connected state to the disconnected state is adopted. Therefore, since the pressure may temporarily increase during the switching, hydraulic pressure should always be supplied to the friction clutch. Compared with the structure described above, the clutch hydraulic capacity (capacity of the hydraulic storage / supply means) is also advantageous in that it is relatively small.

These and other features of the present invention, as well as the operational effects and advantages thereof, will be understood by reading the following description with reference to the accompanying drawings.

(Embodiment of invention)

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the work machine which concerns on this invention is described based on two cases and the self-held combine which is an example of a work machine, referring drawings.

In addition, in the following description, the "full swing" of the body means that both the left and right steering devices are driven, but the traveling device on the outside of the drive is driven at a higher speed, and the traveling device on the inside of the revolution is at a lower speed. The turning is performed in the driving state. In addition, the " rapid turning " of the body refers to a turning performed in a state where only the traveling device outside the swing is driven, and the traveling device inside the swing is braked (stopped). In our industry, "sharp turn" is also called "pivot turn."

[First embodiment]

In Fig. 1, the whole side of the associated self-deleting combine is shown.

This combine combines the harvesting conveying apparatus 3 which harvests a grain stem in front of the traveling body 2 which travels by operation of a pair of crawler-type traveling apparatus 1 which is an example of a traveling apparatus, and conveys it toward the rear. A threshing apparatus 4 for storing the grains from the threshing apparatus 4 connected to the elevating body 2 and receiving threshing stems from the mowing conveying apparatus 3 and performing threshing / selection processing on the traveling body 2. It is comprised by mounting the grain tank 5, and forming the boarding drive part 6 in the front part of the grain tank 5. As shown in FIG.

As shown in FIG. 2 and FIG. 3, the combine uses the belt-tension-type main clutch 10 as the hydrostatic stepless speed changer 9 equipped with the power from the engine 7 to the mission case 8. And transmits the power after the shift by the hydrostatic stepless speed changer 9 to the right and left crawler type travel devices 1 through the driving electric system 11 built in the lower half of the mission case 8. It is comprised so that it may be made, and operation of the peripheral speed lever which is not shown in figure connected with the hydrostatic stepless speed change apparatus 9 is made to switch back and forth and stepless speed change.

The hydrostatic stepless speed change apparatus 9 accommodates an axial piston pump 14 and a piston motor 15 in an inwardly facing recess 13 formed in the left wall 12 of the mission case 8. , The concave portion 13 is closed by connecting the port block 18 having the forward flow path 16 or the reverse flow path 17 connecting the piston pump 14 and the piston motor 15 to the left wall 12. It consists of doing.

The driving electric motor 11 has an operating state (driving or driving stopping) of the gear type transmission 19 to which power is transmitted from the hydrostatic stepless speed transmission 9 and the crawler type traveling device 1 on either side. And a hydraulic steering device 20 for steering the traveling body 2 by switching the speed difference between the right and left crawler traveling devices 1 and the like, and the gear transmission 19 By operating the sub-shift lever (not shown) in conjunction with the above), the hydrostatic stepless transmission 9 is capable of shifting the power after the shifting into two stages of elevation.

On the upper part of the mission case 8, the electric system 22 for work which transmits the power before shifting by the hydrostatic stepless speed transmission 9 to the mowing conveying apparatus 3 via the belt tension mowing clutch 21. Is built in. The electric motor 22 for work transmits the power from the engine 7 by the operation of the work lever which is not shown in connection with the low speed electric motor which drives the mowing conveyance apparatus 3 at a suitable working speed at the time of medium and low speed running. It is configured to shift to the two stages of the high speed electric motor which drives the mowing and conveying apparatus 3 at a suitable working speed at the time of high speed driving, and shows the driving state of the preliminary conveying apparatus 3 suitable for the traveling speed. In this way, the preliminary conveyance of grain stems is performed smoothly.

As shown in Figs. 2 to 5, the steering apparatus 20 includes left and right engagement clutches 23 for blocking and connecting transmission from the gear type transmission 19 to the corresponding crawler type traveling apparatus 1, It is possible to cut off the left and right multi-plate brakes 24 and the corresponding engagement clutch 23 against the pressure of the spring 25 and to brake the multi-plate brakes 24 to the corresponding crawler type traveling device 1. The hydraulic cylinder 26 of the left and right, and the hydraulic-type multi-ply friction clutch 29 which enable the drive shaft 28 to connect in the crawler-type traveling apparatus 1 of right and left which resisted the pressurization of the spring 27. ), And the like.

The switching of the operating state of the steering apparatus 20 can be performed by adjusting the flow rate of the mission oil pumped by the hydraulic pump 30 as the hydraulic oil of the left and right hydraulic cylinder 26 and the friction clutch 29, and adjusting the flow rate. Can be performed by controlling the operations of the relief valve 32, the first switching valve 33, the variable relief valve 34, and the second switching valve 35 provided in the steering flow path 31. The control of these operations is performed by the operation of the operation lever 36 in conjunction with 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 selector valve 33 stops the flow of the hydraulic oil from the hydraulic pump 30 and at the same time the hydraulic oil from the left and right hydraulic cylinders 26 is changed. From the hydraulic pump 30, it is switched to the neutral state which allows discharge, and the operating lever 36 is located between the neutral position N and either of the left and right first pivot positions L1 and R1. Instead of supplying the hydraulic oil to the left and right hydraulic cylinders 26, they are reduced into the mission case 8 and are switched to either the left or the right turn switching state to allow the hydraulic oil to be discharged from the left and right hydraulic cylinders 26. When the operation lever 36 is operated into the swing operation area extending from either of the left and right first swing positions L1 and R1 to the second swing positions L2 and R2, the hydraulic cylinder corresponding to the operation direction ( 26 allows the supply of hydraulic oil from the hydraulic pump 30 to the operating direction and Contrary to this, the hydraulic cylinder 26 is switched to one of the left and right turning states allowing the discharge of the hydraulic oil from the hydraulic cylinder 26. The variable relief valve 34 has a relief pressure of zero while the operation lever 36 is operated across the neutral position N and the left and right first swing positions L1 and R1, and the left and right sides are Is set so as to be larger from the first turning positions L1 and R1 to the second turning positions L2 and R2, and the relief pressure is increased. The second switching valve 35 allows the discharge of the hydraulic oil from the friction clutch 29 when the hydraulic pressure in the supply passage 37 from the hydraulic pump 30 to the first switching valve 33 exceeds the set value. When it is switched to the discharged state and the oil pressure in the supply passage 37 becomes lower than the set value, it is switched to the supply state that allows the supply of the hydraulic oil to the friction clutch 29.

From the above structure, the steering apparatus 20 can represent each operation state of a combine (work vehicle) as follows.

(Transition from straight state to left turn state)

In the state where the operation lever 36 is located at the neutral position N, the neutral state of the first selector valve 33 is shown, and the discharge state of the second selector valve 35 is shown, whereby the left and right The hydraulic oil is discharged from the hydraulic cylinder 26 of the hydraulic cylinder 26, and the electric state of the left and right engagement clutches 23 and the non-braking state of the left and right multi-plate brakes 24 appear, and the hydraulic oil is discharged from the friction clutch 29. The state in which the friction clutch 29 is cut off appears, and the steering apparatus 20 is in a straight traveling state in which the right and left crawler-type traveling devices 1 are driven at constant speed by electric power through the left and right engagement clutches 23. To indicate

Then, when the operation lever 36 is operated from the neutral position N toward the first swing position L1 on the left side, the operation lever 36 is operated on the left first swing position L1 from the neutral position N. In the meantime, the first switching valve 33 is switched to the straight left swing switching state, and the second switching valve 35 is switched to the supply state, whereby the left and right engagement clutches 23 are turned on. While the motor-driven state and the non-braking state of the left and right multi-plate brakes 24 are continued, the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29 so that the friction clutch 29 is connected from the blocked state to the connected state. Is switched. From this, the left and right engagement clutch 23 and the friction clutch 29 at the time of starting the left turning run until the operation lever 36 is operated from the neutral position N to the left first swing position L1. It is intended to represent a straight running state in which the crawler-type traveling device 1 on the right and left is driven at a constant speed by electric power through the motor.

Thereafter, when the operation lever 36 is operated to the first swing position L1 on the left side, the first switch valve 33 is switched to the left swing state. As a result, first, hydraulic oil from the hydraulic pump 30 is supplied to the hydraulic cylinder 26 on the left side, and the hydraulic cylinder 26 on the left side communicates the first switching valve 33 and the movable relief valve 34. It operates until the state to which it is made, and the left engagement clutch 23 switches to a non-electric state from an electric state. As a result, a straight running state in which the right and left crawler-type traveling devices 1 are driven at constant speed only by transmission through the friction clutch 29 is shown. Then, the relief pressure of the variable relief valve 34 becomes zero at this operating position. Since the hydraulic oil supplied to the hydraulic cylinder 26 on the left side from the hydraulic pump 30 is discharged through the variable relief valve 34 as it is, the left engagement clutch 23 is maintained in a non-driven state, The switching from the non-driven state of the multi-plate brake 24 to the braking state is prevented. Further, at the operating pressure when the left engagement clutch 23 is switched from the electric state to the non-electric state, the second switching valve 35 is switched to the discharge state, and the hydraulic oil in the friction clutch 29 is gradually discharged. The friction clutch 29 is gradually switched from the connected state to the blocked state. From this, while driving the crawler-type traveling device 1 on the right side, the leftward turning state for driving the crawler-type traveling device 1 on the left side is gradually switched and shown.

That is, when switching from the straight traveling state to the left complete turning state, first, in the crawler-type traveling device 1 on the right in which transmission is continued by the right engagement clutch 23, the left engagement clutch 23 is used. The constant-speed transmission state through the friction clutch 29 to the crawler-type traveling device 1 on the left side of which the transmission was cut off appears, and then the left side of the crawler-type traveling device 1 on the right side through the friction clutch 29 is displayed. Since the transmission to the crawler-type traveling device 1 is gradually weakened and the crawler-type traveling device 1 on the left side is driven, the crawler-type traveling device on the left side (even if the running road surface is in a weak state with a large running resistance) The driving speed of 1) can be lowered gradually, so that the transition from the straight traveling state to the left full swing state is performed smoothly.

(Transition from left turn to left turn)

Thereafter, when the operation lever 36 is operated from the first swing position L1 on the left side to the second swing position L2 and operated, the relief pressure of the variable relief valve 34 becomes large as the amount of the operation is large. At the same time as the operating flow rate supplied to the hydraulic cylinder 26 of the multi-plate brake 24 on the left side is gradually switched to the braking state. In this way, the left turning condition for braking the crawler type traveling device 1 on the left side from one side driving the crawler type traveling device 1 on the right side to the left crawler type traveling device 1 in the left complete turn state. It is possible to appear smoothly with the braking gradually becoming strong.

(Switching from left turn to left turn)

Conversely, when the operation lever 36 is operated from the second swing position L2 on the left side to the first swing position L1, the relief pressure of the variable relief valve 34 becomes smaller as the amount of the operation is greater, The operating flow rate discharged from the hydraulic cylinder 26 of the engine increases and the braking by the left multi-plate brake 24 gradually weakens. Then, the operating lever 36 operates the first swing position L1 on the left side. In this case, since the relief pressure of the variable relief valve 34 becomes zero and the left multi-plate brake 24 is switched to the non-driven state, the crawler type traveling device on the left indicates that the switching from the left turn to the left turn is performed. It is supposed to perform smoothly in a state where braking against 1) is gradually weakened.

(Switching from left turn to straight driving)

Next, when the operating lever 36 is operated toward the neutral position N from the first swing position L1 on the left side, the operating lever 36 is the neutral position N at the first swing position L1 on the left side. In the meantime, the first switching valve 33 is switched to the straight left swing switching state, and the second switching valve 35 is switched to the supply state, whereby the hydraulic pump 30 The hydraulic oil is supplied to the friction clutch 29 so that the friction clutch 29 is gradually switched to the connected state from the blocked state. In this way, transmission from the crawler-type traveling device 1 on the right side through the friction clutch 29 to the crawler-type traveling device 1 on the left side is started, and the crawler-type traveling device 1 on the left side is driven at the same time. This gradually becomes stronger so that the driving speed of the crawler-type traveling device 1 on the left is gradually increased. Thereafter, when the operation lever 36 is operated to the neutral position N, the first switching valve 33 is switched to the neutral state and the second switching valve 35 is switched to the discharged state. The hydraulic oil is discharged from the hydraulic cylinder 26 on the left side, and the engagement clutch 23 on the left side is switched from the non-electric state to the electric state, and the hydraulic oil is discharged from the friction clutch 29, thereby switching the friction clutch 29 to the blocking state. do. In this way, the switching to the straight running state in which the right and left crawler-type traveling devices 1 are driven at constant speed by electric transmission through the left and right engagement clutches 23 is performed smoothly in the left complete turning state.

(Transition from straight to right turn)

On the other hand, when the operation lever 36 is operated toward the first pivot position R1 on the right side from the neutral position N, the operation lever 36 moves to the first pivot position R1 on the right side from the neutral position N. Until this time, the first switching valve 33 is switched to the straight priority switching state and the second switching valve 35 is switched to the supply state. Thereby, while the transmission state of the left and right engagement clutch 23 and the non-driven state of the left and right multi-plate brakes 24 continue, the hydraulic oil from the hydraulic pump 30 is supplied to the friction clutch 29, and the friction clutch (29) is switched from the disconnected state to the connected state. At this time, at the start of the priority driving from the neutral position N to the right first pivot position R1, the left and right engagement clutch 23 and the friction clutch 29 are operated. It is intended to represent a straight running state in which the right and left crawler-type traveling device 1 is driven at a constant speed by electric transmission through.

Thereafter, when the operation lever 36 is operated to the first turning position R1 on the right side, the first switching valve 33 is switched to the priority state, whereby the hydraulic pump 30 The hydraulic oil is supplied to the hydraulic cylinder 26 on the right side, the hydraulic cylinder 26 on the right side operates until the first switching valve 33 and the variable relief valve 34 communicate with each other, and the right engagement clutch 23 Is converted from the electric state to the non-electric state, indicating a straight traveling state in which the right and left crawler-type traveling devices 1 are driven at constant speed only by electric power through the friction clutch 29, and thereafter, the variable relief valve ( Since the relief pressure of 34 is zero and the hydraulic oil supplied from the hydraulic pump 30 to the hydraulic cylinder 26 on the right side is discharged through the variable relief valve 34 as it is, the right engagement clutch 23 is in a non-driven state. And the non-braking phase of the multi-plate brake 24 on the right side The switching to the braking state is prevented, and the second switching valve 35 is switched to the discharged state at the operating pressure when the engagement clutch 23 on the right side is switched from the electric state to the non-driven state, and the friction Since the hydraulic oil in the clutch 29 is gradually discharged and the friction clutch 29 is gradually switched from the connected state to the blocked state, the crawler type traveling device 1 on the right side is driven while driving the crawler type traveling device 1 on the left side. The right turn condition that follows is gradually switched to indicate.

In other words, when switching from the straight running state to the right turn state, first, in the crawler-type traveling device 1 on the left in which transmission is continued by the left engagement clutch 23, the right engagement clutch 23 is used. The constant-speed driving state appears through the friction clutch 29 to the crawler-type traveling device 1 on the right side in which power transmission is cut off, and then, on the right side of the crawler-type traveling device 1 on the left side through the friction clutch 29, Since the transmission to the crawler-type traveling device 1 is gradually weakened and the crawler-type traveling device 1 on the right side is driven, the crawler-type traveling device 1 on the right side can be driven even if the running surface is in a weak state with a large running resistance. ), The driving speed can be decreased gradually, and the transition from the straight state to the right turn state is performed smoothly.

(Transition from right turn to right turn)

Thereafter, when the operation lever 36 is operated from the first swing position R1 on the right side to the second swing position L2, the relief pressure of the variable relief valve 34 becomes large as the amount of the operation is large, and the right side Since the operating flow rate supplied to the hydraulic tank 26 increases, the multi-plate brake 24 on the right side is gradually switched to the braking state, and the crawler-type traveling device on the right side is driven while driving the crawler-type traveling device 1 on the left side. The right turning state for braking (1) is smoothly shown in a state in which the braking to the crawler-type traveling device 1 on the right side gradually becomes stronger in the right turning state.

(Switching from right turn to right turn)

Conversely, when the operation lever 36 is operated from the second swing position L2 on the right side to the first swing position R1, the relief pressure of the variable relief valve 34 decreases as the operation amount is larger, and the right side The hydraulic flow rate discharged from the hydraulic cylinder 26 increases, and the braking by the multi-plate brake 24 on the right side gradually weakens. Then, the operating lever 36 operates the first turning position R1 on the right side. When the relief pressure of the variable relief valve 34 becomes 0, the multi-plate brake 24 on the right side is switched to the non-braking state, and thus, the crawler-type traveling device on the right side indicates switching from the right turn state to the right turn state. The braking against (1) is performed smoothly in a state where it gradually weakens.

(Switching from the right turn to the straight driving state)

Next, when the operating lever 36 is operated toward the neutral position N from the first turning position R1 on the right side, the operating lever 36 is the neutral position N at the first turning position R1 on the right side. During this time, the first switching valve 33 is switched to the straight ahead switching state, and the second switching valve 35 is switched to the supply state, whereby the hydraulic pump 30 Hydraulic oil is supplied to the friction clutch 29, and the friction clutch 29 is gradually switched to the connected state from the blocked state. Thereby, transmission from the crawler type traveling device 1 on the left side through the friction clutch 29 to the crawler type traveling device 1 on the right side is started, and the crawler type traveling device 1 on the right side is driven, and Transmission is gradually increased so that the driving speed of the crawler-type traveling device 1 on the right is gradually increased. Thereafter, when the operation lever 36 is operated to the neutral position N, the first switching valve 33 is switched to the neutral state and the second switching valve 35 is switched to the discharged state. The hydraulic oil is discharged from the hydraulic cylinder 26 on the right side and the engagement clutch 23 on the right side is switched from the non-driven state to the electric state, and the hydraulic oil is discharged from the friction clutch 29 to switch the friction clutch 29 to the blocked state. do. In this way, it is possible to smoothly show the switching to the straight running state in which the right and left crawler-type traveling devices 1 are driven at constant speed by electric power through the right and left engagement clutches 23 in the right turn state.

Further, in the above configuration, at the end of the turning run in which the operation lever 36 is operated to the neutral position N, for example, until the engagement clutch 23 on either of the left and right sides is switched from the non-motor state to the electric state. In the meantime, the left and right crawler-type traveling devices 1 reach the constant speed driving state by transmission through the friction clutch 29, and the engagement clicks of the engagement clutches 23 that are switched to the electric state from the non-driven state cannot be engaged. Even if it is made to rotate at a constant speed as it is, the steering apparatus 20 is a crawler-type traveling device of right and left by electric transmission through both left and right engagement clutches 23 while operating the operation lever 36 to the neutral position N. It is possible to clearly indicate the straight running state in which (1) is driven at constant speed.

That is, as the operation lever 36 is operated to the neutral position (N), the discharge state of the second switching valve 35 is shown so that the friction clutch 29 is switched from the connected state to the blocked state, the right and left crawler type Since the traveling device 1 is differential and the non-driven engagement clutch 23 has a difference in the rotational phase between the engagement clicks, the non-driven engagement clutch 23 can be switched to the electric state. Therefore, the steering apparatus 20 drives the crawler-type traveling apparatus 1 at the right and left sides by electric power through the left and right engagement clutch 23 in the state where the operation lever 36 is operated to the neutral position N. FIG. It can clearly indicate the driving condition.

Although not shown, the multi-plate brake 24 on the right side is connected to the brake pedal together with the main clutch 10, and the main clutch 10 is driven by the engine 7 by stepping on the brake pedal. The deceleration stop state in which the transmission to the hydraulic continuously variable transmission 9 is interrupted and the multi-plate brake 24 brakes the crawler-type traveling device 1 on the left and right through the steering device 20 can also be shown. By holding the pedal at the step of operating the pedal with the lock bracket, the parking state in which the multi-plate brake 24 functions as the parking brake is shown.

In this regard, as shown in FIG. 5, in the flow path portion above the hydraulic pump 30 in the steering flow path 31, the charge flow path 38 for the hydrostatic continuously variable transmission 9 is provided. Is connected to the flow path 38, the hydraulic pump 39 for charge, the check valve 40 for the forward flow path 16, the check valve 41 for the reverse flow path 17, and the forward flow path. The neutral valve 42 and the relief valve 43 with respect to (16) are provided, and return oil from this relief valve 43 is supplied to the hydrostatic stepless speed change apparatus 9 for cooling.

Second Embodiment

Next, a second embodiment of the present invention will be described with reference to FIG. 6. In the second embodiment, the operating state switching structure of the steering apparatus 20 differs from the following in comparison with the first embodiment.

As shown in FIG. 6, the switching of the operating state of the steering apparatus 20 adjusts the flow rate of the mission oil that is pumped by the hydraulic pump 30 as the hydraulic oil of the left and right hydraulic cylinders 26 and the friction clutch 29. The flow rate adjustment controls the operation of the relief valve 32, the switching valve 44, the variable relief valve 34, and the pressure reducing valve 45 provided in the steering flow path 31. The operation control can be performed by operating the operating lever 36 in conjunction with the selector valve 44 and the variable relief valve 34. When the switching valve 44 is operated in the neutral region from the operating lever 36 to the left and right first swing positions L1 and R1 at the neutral position N, the switching valve 44 is operated at the hydraulic pump 30. The hydraulic pump 30 is stopped when the flow is stopped and at the same time it is switched to the neutral state to allow the hydraulic oil to be discharged from the left and right hydraulic cylinders 26 and the operating lever 36 is operated near the neutral position N. ), A pressure reducing state for reducing the hydraulic pressure in the supply passage 37 extending from the hydraulic pump 30 and extending from the hydraulic pump 30 to the first switching valve 33, is temporarily shown. When the 36 is operated into the swing operation area extending from the first swing position L1, R1 on either of the left and right sides, to the second swing position L2, R2, the hydraulic pressure to the hydraulic cylinder 26 corresponding to the operation direction is At the same time allowing the supply of hydraulic oil from the pump 30, the hydraulic cylinder 26 against the operation direction It is to be switched to either left or right turning state to allow the discharge of hydraulic oil. The variable relief valve 34 has a relief pressure of 0 while the operation lever 36 is operated across the neutral position N and the left and right first swing positions L1 and R1, and the left and right sides of the variable relief valve 34 It is set so that the relief pressure becomes large as much as it is operated largely from the 1st turning position L1, R1 to the 2nd turning position L2, R2 side.

In the above structure, the steering apparatus 20 can represent each operation state of a combine (work vehicle) as follows.

(Transition from straight to left turn)

In the state where the operation lever 36 is located in the neutral position N, the neutral state of the selector valve 44 is shown, whereby the hydraulic oil is discharged from the hydraulic cylinders 26 on the left and right sides. The transmission state of the engagement clutch 23 and the non-operation state of the left and right multi-plate brakes 24 are shown, and the hydraulic oil is supplied to the friction clutch 29 through the pressure reducing valve 45 so that the friction clutch 29 The connection status of is displayed. In this case, the steering apparatus 20 is configured to exhibit a straight running state in which the right and left crawler-type traveling devices 1 are driven at the same speed by electric power through the left and right engagement clutch 23 and the friction clutch 29.

Then, when the operating lever 36 is operated from the neutral position N to the first swing position L1 on the left side, the selector valve 44 is switched to the left swing state, whereby first in the complete swing state Of the operating oil is supplied to the hydraulic cylinder 26 on the left side, the hydraulic cylinder 26 on the left side operates until the switching valve 44 and the variable relief valve 34 communicate with each other, and the left engagement clutch 23 Transition from electric state to non-electric state. This shows a straight traveling state in which the right and left crawler-type traveling device 1 is driven at constant speed only by transmission through the friction clutch 29. Thereafter, the relief pressure of the variable relief valve 34 becomes zero at this operation position, and the hydraulic oil supplied from the hydraulic pump 30 to the hydraulic cylinder 26 on the left side is discharged through the variable relief valve 34 as it is. At the same time, the left engagement clutch 23 is kept in the non-driven state and at the same time, the switching of the left-side multi-plate brake 24 from the non-driven state to the operating state is prevented, and by the operation of the pressure reducing valve 45, the friction clutch ( The hydraulic oil in 29 is gradually discharged, and the friction clutch 29 is gradually switched from the connected state to the blocked state. In this way, the right turn state for driving the crawler-type traveling device 1 on the left side while driving the crawler-type traveling device 1 on the right side is gradually switched.

In other words, when switching from the straight running state to the left complete turning state, first, in the crawler-type traveling device 1 on the right side where the transmission is continued by the right engagement clutch 23, the left engagement clutch 23 is used. The constant-speed electric state through the friction clutch 29 to the crawler-type traveling device 1 on the left side in which power transmission was cut off appears. Thereafter, transmission from the crawler-type traveling device 1 on the right through the friction clutch 29 to the crawler-type traveling device 1 on the left is gradually weakened, and the crawler-type traveling device 1 on the left is driven. . In this way, even if the state of the runway surface is a weak state with a large running resistance, the driving speed of the crawler type traveling device 1 on the left side may gradually decrease, and the transition from the straight state to the left turn state is smooth. It is to be done.

(Transition from left turn to left turn)

Thereafter, when the operation lever 36 is operated from the first swing position L1 on the left side to the second swing position L2, the relief pressure of the variable relief valve 34 becomes large as the amount of the operation is large. The operating flow rate supplied to the hydraulic cylinder 26 of the engine is increased, and at the same time, the multi-plate brake 24 on the left side is gradually switched to the braking state. In this way, the left turning condition for driving the crawler type traveling device 1 on the right side and braking the crawler type traveling device 1 on the left side is performed with respect to the crawler type traveling device 1 on the left side in the left complete turning state. The braking becomes smooth and can be displayed smoothly.

(Switching from left turn to left turn)

Conversely, when the operation lever 36 is operated from the second swing position L2 on the left side to the first swing position L1, the relief pressure of the variable relief valve 34 becomes smaller as the amount of the operation is larger, The operating flow rate discharged from the hydraulic cylinder 26 on the left side increases, and the braking is gradually weakened by the multi-plate brake 24 on the left side. Then, the operation lever 36 moves to the first swing position L1 on the left side. When operated, the relief pressure of the variable relief valve 34 becomes zero, and the left multi-plate brake 24 is switched to the non-braking state. Thus, the left crawler type running is indicated to indicate the switching from the left turn to the left full turn. The braking to the device 1 is performed smoothly in a state where the braking is gradually weakened.

(Switching from left turn to straight driving)

Next, when the operation lever 36 is operated to the neutral position N from the first swing position L1 on the left side, the selector valve 44 is switched to the neutral state. As a result, the hydraulic oil is discharged from the hydraulic cylinder 26 on the left side, and the left engagement clutch 23 is switched from the power distribution state to the electric state. On the other hand, during the switching operation, by operating the pressure reducing valve 45 in accordance with the switching of the switching valve 44 to the neutral state, the hydraulic oil in the hydraulic pump 30 is supplied to the friction clutch 29, and the friction The clutch 29 is gradually switched from the disconnected state to the connected state. Thus, transmission of the crawler-type traveling device 1 on the right side to the crawler-type traveling device 1 on the left side is started through the friction clutch 29, and the crawler-type traveling device 1 on the left side is driven and the transmission This gradually becomes strong, and the drive speed of the crawler-type traveling device 1 on the left side is gradually increased. In this way, the switching to the straight running state in which the left and right crawler-type traveling devices 1 are driven at constant speed by electric transmission through the left and right engagement clutch 23 and the friction clutch 29 is performed smoothly. It is.

(Transition from straight to right turn)

On the other hand, when the operation lever 36 is operated from the neutral position N to the right first swing position R1, the switching valve 44 is switched to the priority swing state, whereby the hydraulic pump 30 is firstly operated. The hydraulic fluid in the above) is supplied to the hydraulic cylinder 26 on the right side, the hydraulic cylinder 26 on the right side operates until the switching valve 44 and the variable relief valve 34 communicate with each other, and the right engagement clutch 23 ) Is changed from electric state to non-electric state. This shows a straight traveling state in which the right and left crawler-type traveling device 1 is driven at constant speed only by transmission through the friction clutch 29. Thereafter, the relief pressure of the variable relief valve 34 becomes zero at this operation position, and the hydraulic oil supplied from the hydraulic pump 30 to the hydraulic cylinder 26 on the right side is discharged through the variable relief valve 34 as it is. At the same time, the engagement clutch 23 on the right side is kept in the non-driven state, and the switching from the non-braking state on the right side of the multi-plate brake 24 to the braking state is prevented, and by the operation of the pressure reducing valve 45, the friction clutch The hydraulic oil in (29) is gradually discharged, and the friction clutch 29 is gradually switched from the connected state to the blocked state. In this way, the right turn state for driving the crawler-type traveling device 1 on the left side and driving the crawler-type traveling device 1 on the right side is gradually switched and shown.

That is, when switching the right turn state from the straight traveling state, first, in the crawler-type traveling device 1 on the left in which transmission is continued by the left engagement clutch 23, the right engagement clutch 23 is used. The constant-speed electric state through the friction clutch 29 to the crawler-type traveling device 1 on the right side in which electric power was cut off appears. Then, since the transmission from the crawler-type traveling device 1 on the left side through the friction clutch 29 to the crawler-type traveling device 1 on the right is gradually weakened, the crawler-type traveling device 1 on the right is driven. have. In this way, even if the state of the runway surface is a weak state with a large running resistance, the drive speed of the crawler type traveling device 1 on the right side can be gradually lowered, and the transition from the straight state to the right turn state is smooth. It is to be done.

(Transition from right turn to right turn)

Thereafter, when the operation lever 36 is operated from the first swing position R1 on the right side to the second swing position L2, the relief pressure of the variable relief valve 34 becomes large as the amount of the operation is large. The operating flow rate supplied to the hydraulic cylinder 26 of the engine is increased, and the multi-plate brake 24 on the right side is gradually switched to the braking state. In this way, the right turning state for driving the crawler type traveling device 1 on the left side and braking the crawler type traveling device 1 on the right side is performed with respect to the crawler type traveling device 1 on the right side in the right turn state. It is designed to appear smoothly with the braking gradually becoming strong.

(Switching from right turn to right turn)

Conversely, when the operation lever 36 is operated from the second swing position L2 on the right side to the first swing position R1, the relief pressure of the variable relief valve 34 decreases as the operation amount is larger, and the right side The hydraulic flow rate discharged from the hydraulic cylinder 26 of the large and at the same time the braking by the multi-plate brake 24 on the right side is gradually weakened. Thereafter, when the operation lever 36 is operated to the first swing 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 inoperative state.

In this way, the switching from the right turn state to the right turn state is smoothly performed in a state where braking to the crawler-type traveling device on the right side is gradually weakened.

(Switching from the right turn to the straight driving state)

Next, when the operation lever 36 is operated to the neutral position N from the first turning position R1 on the right side, the selector valve 44 is switched to the neutral state. As a result, the hydraulic oil is discharged from the hydraulic cylinder 26 on the right side, and the right engagement clutch 23 is switched from the non-electric state to the electric state. On the other hand, during the switching operation, by operating the pressure reducing valve 45 in accordance with the switching of the switching valve 44 to the neutral state, the hydraulic oil in the hydraulic pump 30 is supplied to the friction clutch 29, and the friction The clutch 29 is gradually switched from the disconnected state to the connected state. As a result, transmission of the crawler-type traveling device 1 on the right side to the crawler-type traveling device 1 on the right side is started through the friction clutch 29, and the crawler-type traveling device 1 on the right side is driven. This gradually becomes stronger so that the driving speed of the crawler type traveling device 1 on the right side becomes gradually higher. From this, it is transmitted smoothly through the left and right engagement clutch 23 and the friction clutch 29 in the right turn state so that the left and right crawler type traveling devices 1 are smoothly shown to be converted to the straight running state driven at constant speed. do.

Further, by the above configuration, at the end of the turning run in which the operation lever 36 is operated to the neutral position N, for example, when either of the left and right engagement clutches 23 is switched from the non-driven state to the electric state. In the meantime, the left and right crawler-type traveling devices 1 reach the constant speed driving state by transmission through the friction clutch 29, and the engagement clicks of the engagement clutches 23 switched from the non-driven state to the electric state cannot be engaged. Even if it is made to rotate at constant speed as it is in one rotational phase, the steering apparatus 20 is operated through the left and right engagement meshes 23 and the friction clutch 29 in the state which operated the operation lever 36 to the neutral position N. It is possible to reliably indicate the straight running state in which the crawler-type traveling device 1 on both sides is driven at constant speed by electric transmission.

That is, as the operation lever 36 is operated in the vicinity of the neutral position N, the depressurization state of the selector valve 44 appears temporarily, and by the operation of the decompression valve 45 accordingly, the friction clutch ( The hydraulic oil in 29 is discharged and the friction clutch 29 is operated to switch from the connected state to the blocked state. As a result, the right and left crawler-type traveling devices 1 are differential, so that a difference occurs in rotational phases between the engaging clicks in the non-driven engagement clutch 23. Then, in the state where the operating lever 36 is positioned at the neutral position N, the steering apparatus 20 is a crawler-type traveling device on the left and right by electric transmission through the left and right engagement meshes 23 and the friction clutch 29. The straight running state which drives (1) at constant speed can be clearly shown.

[Other Embodiments]

Hereinafter, other embodiment of this invention is listed.

(1) As a working machine, in addition to the combine shown, ginseng harvester, anhydrous harvester, etc. may be sufficient.

(2) The steering apparatus 20 may be configured such that only the complete turning state can be displayed, that is, the sudden turning state does not appear.

According to the present invention, at the start of the turning drive for switching one engagement clutch to the non-driven state, the connection state of the friction clutch is shown in the stage before the one engagement clutch is switched from the electric state to the non-driven state. Power is transmitted from one traveling device that is powered off by the engagement clutch to the other traveling device which is powered by the other engagement clutch through the friction clutch, and through the friction clutch. Transmission is released gradually. From this, for example, even if the state of the traveling road surface is in a weak state with a large running resistance, the running resistance can avoid sudden stop when the driving device is cut off by the corresponding engagement clutch. Therefore, the transition from the straight driving state to the turning driving state is smoothly performed.

Next, at the end of the turning drive in which the one engagement clutch is switched from the non-driven state to the electric state, one traveling device whose electric power is cut off by the one engagement clutch before the one engagement clutch is switched to the electric state. Then, the power from the other traveling device in which transmission continues by the other engagement clutch is gradually transmitted through the friction clutch. From this, sudden start and stop of one traveling device due to sudden restart of the transmission to one traveling device by the corresponding engagement clutch can be avoided, so that the transition from the turning driving state to the straight running state is smoothly performed. It is done.

Therefore, in the work machine according to the present invention, the above-mentioned disadvantages are also reliably avoided and reliably avoided for the transition from the straight running state to the turning driving state, and also for the transition from the turning driving state to the straight running state. Operation and linear return operation can be performed smoothly.

In addition to the above configuration, the friction clutch is in a blocking state in the straight traveling state, and at the start of the turning driving, the friction clutch is in a connected state before the one engagement clutch is switched from the electric state to the non-electric state. If it is comprised, it is advantageous at the following points.

Advantageously, in the present invention, since it is configured to show the blocking state of the friction clutch in the straight driving state, at the end of the turning driving, for example, the above-described situation (until one engagement clutch is switched from the non-electric state to the electric state). Even if the right and left traveling devices reach the constant speed driving state by the transmission through the friction clutch, and the engagement clicks of one of the engagement clutches are made to rotate at the same speed as the non-engaging rotation phase), thereafter, The friction clutch is transferred from the connected state to the disconnected state. Since the friction clutch is switched to the shut-off state, the left and right traveling devices are differential, and a difference in the rotational phases between the engagement clicks in the engagement clutch is possible, so that one engagement clutch can be switched from the non-driven state to the electric state. do. As a result, it is possible to reliably indicate the straight traveling state in which the left and right traveling devices are driven at constant speed by the electric transmission through the left and right engagement clutches.

Furthermore, for example, when switching from the turning driving state to the straight driving state, even if one of the engagement clutches is not engaged, the straight driving state in which the left and right traveling devices are driven at the same speed by the friction clutch is temporarily displayed. In the state, the state of the friction clutch is cut off, and the non-driven engagement clutch is switched to the electric state. When switching in this way, there is no transmission through the friction clutch thereafter, and the left and right traveling devices are driven at constant speed by the transmission through the friction clutches on the left and right sides. The friction clutch is in a non-driven state so that it is possible to surely avoid the occurrence of the disadvantage that the vehicle stops running without turning.

Therefore, it is possible to more reliably avoid the occurrence of the above-mentioned disadvantages, particularly when the turning driving state is switched and displayed in the straight driving state.

Furthermore, if the friction clutch is configured to temporarily switch operation from the connected state to the disconnected state immediately before the one engagement clutch is switched from the non-driven state to the electric state at the end of the turning run, the following points will be given. It is advantageous.

According to this configuration, at the end of turning driving, for example, the driving device on the left and right reaches the constant speed driving state by the transmission through the friction clutch, for example, until one of the engagement clutches is switched from the non-driven state to the electric state. . Even if the engagement clicks of the one engagement clutches are rotated at constant speed as they are in a non-engaged rotational phase, the friction clutch is operated from the connected state to the disconnected state just before the one engagement clutch is switched to the electric state, thereby allowing the left and right traveling devices to In the differential clutch, a difference occurs in rotational phases between the engaging clicks. As a result, one of the engagement clutches is switched from the non-driven state to the electric state, and as a result, it is possible to represent a straight running state in which the left and right traveling devices are driven at constant speed by electric transmission through the left and right engagement meshes.

That is, when the transition from the turning driving state to the straight driving state is indicated, even if the straight driving state in which the left and right traveling devices are driven at constant speed by electric transmission through the friction clutch is temporarily indicated, one of the engagement clutches is switched from the non-drive state to the electric state. Immediately before the friction clutch is engaged, the clutch clutch is temporarily switched from the connected state to the disconnected state, and the non-driven engagement clutch is transferred to the electric state, and not only through the friction clutch but also through the left and right engagement clutches. Since the traveling device is designed to be driven at constant speed, the left and right interlocking clutches are in the non-driven state when switching from the straight driving state to the turning driving state, thereby avoiding the disadvantage of stopping the vehicle without turning. do.

Therefore, in particular, the occurrence of the above-described disadvantages when switching the turning driving state in the straight driving state can be more surely avoided.

In the case where the friction clutch is hydraulic, the structure in which the friction clutch is temporarily switched from the connected state to the disconnected state is adopted. Therefore, since the pressure may temporarily increase during the switching, hydraulic pressure should always be supplied to the friction clutch. Compared with the structure described above, the clutch hydraulic capacity (capacity of the hydraulic storage / supply means) is also advantageous in that it is relatively small.

Claims (4)

Left and right traveling devices (1, 1), Left and right engagement clutches 23 and 23, which are provided in the electric system for the left and right traveling devices, and block or connect the transmission to the corresponding traveling devices; As a work machine which is provided with respect to the left and right traveling devices, and is provided with the left and right drive shafts 28 and 28 for driving the corresponding traveling devices, When the left and right engagement clutches are switched to the electric state, the straight running state is displayed, and at the start of turning driving, one of the engagement clutches is switched to the non-motor state in the straight driving state, and at the end of the turning driving, In a work machine in which the engagement clutch is configured to switch from a non-driven state to an electric state, A friction clutch 29 capable of interrupting and connecting power transmission between the left and right drive shafts 28 and 28 is provided. This friction clutch 29 At the start of the turning run, the one-to-one clutch is gradually switched from the connected state to the disconnected state in accordance with the switching to the non-driven state. At the end of the turning run, the work machine is configured to be gradually switched from the disconnected state to the connected state before the one engagement clutch is switched to the electric state. The method of claim 1, wherein the friction clutch 29, In the straight traveling state, the state is cut off, And the engagement clutch is configured to be in a connected state before the one-way engagement clutch is switched from the electric state to the non-electric state at the start of the turning run. The method of claim 1, wherein the friction clutch 29, At the end of the turning run, the work machine is configured to temporarily switch operation from the connected state to the disconnected state immediately before the one engagement clutch is switched from the non-driven state to the electric state. The work machine according to any one of claims 1 to 3, wherein the one engagement clutch is an engagement clutch on the side located inside the swing.