JPH0459191B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is mainly used by being installed in agricultural machinery, and is a hydraulic system that enables sharp turns by locking one of the right and left traveling devices when traveling for work in the field. Regarding type side clutches and brakes.

[Conventional technology]

Conventionally, in this type of hydraulic side clutch/brake, a control valve is provided to switch and control the pressure oil supplied to the left and right operating cylinders provided for the left and right side clutches/brakes, respectively. There was a system in which a bypass oil passage was formed from the middle of the piston stroke corresponding to the side clutch disengaged position, and this bypass oil passage was equipped with a variable throttle valve mechanism.
Publication No. 56175).

[Problem that the invention seeks to solve]

However, when making a sharp turn, if the variable throttle valve mechanism is completely closed, the side clutch/brake is activated and the sharp turn can be made. Whether the operation is performed using the operating lever or the pedal, it is difficult to adjust the stroke of these operating tools, and the operating stroke is often insufficient, resulting in poor handbrake effectiveness and sharp turns. There was a fear that it might not be possible. Particularly during turning operations during work traveling, operations such as raising and lowering the working device become congested, so that the operation tool may not be operated sufficiently.

An object of the present invention is to provide a bypass circuit that can improve operability by simply adding a simple mechanism to the bypass circuit.

[Means for solving problems]

The characteristic configuration of the present invention is that a control valve is provided for switching the pressure oil supplied to the left and right operating cylinders provided for the left and right side clutches and brakes, respectively, and the supply pressure oil is removed from each of the operating cylinders. At the same time, connect a bypass oil passage that is capable of , an on-off valve that can be continuously switched for the drain oil passage and a variable relief valve are arranged in series.

[Effect]

According to the above configuration, when pressure oil is supplied to the operation cylinder by operating the control valve,
By simply closing the on-off valve, the handbrake is activated to lock the traveling gear, making it possible to perform sharp turns. In other words, in the present invention, a simple two-position switching operation of closing or opening the on-off valve is sufficient, making the operation easier and more reliable than the conventional operation that involves adjusting the stroke of a variable throttle valve.

In addition, since a variable relief valve is provided in the drain oil passage that communicates with the bypass oil passage in series with the on-off valve, by adjusting the variable relief valve when the on-off valve is in the open state, the piston can disengage the side clutch. It becomes possible to adjust the hydraulic pressure applied to the operating cylinder in the operating state where the brake is further stroked from the position, and it becomes possible to perform sharp turns by adjusting the effectiveness of the brake.

In addition, as one that adopts a similar configuration,
There is a device shown in Publication No. 57-63005, which has a variable relief valve and a modified valve connected in series on the pressure oil flow upper side of the control valve of the operation cylinder, so that the clutch does not operate the brake. The slow turning state caused by the cut-off is unstable and difficult to create and maintain by adjusting the variable relief valve, whereas in the present application, the slow turning state is caused by adjusting the variable relief valve. Since the variable relief valve and the modified valve are connected in series, it is clearly advantageous in that the above-mentioned turning state can be easily and reliably produced.

〔Effect of the invention〕

Therefore, although an operating tool and an on-off valve are added for sharp turns, the operability is improved, and in particular, taking agricultural machinery as an example, turning operations at the edges of ridges where sharp turns are required are ensured. Furthermore, when a sudden turn is not required, such as when driving on a road, arbitrary turning operations can be performed by adjusting the variable relief valve.

As described above, an operation mode suitable for the turning mode can be adopted, and the operability can be further improved.

〔Example〕

As shown in FIG. 4, the combine harvester includes a weeding tool support rod 1, a moving device 2, 2 provided in a grain culm introducing path formed by the weeding tool support rod 1, and a grain culm after being moved. A reaping pretreatment device equipped with a reaping device 3 for reaping grain, a vertical conveyance device 5 for transporting the harvested grain culm toward a threshing device 4, etc. is attached to the front of the machine body 6, and this machine body 6 is moved by a pair of left and right crawlers. Traveling device 7A, 7
It is configured so that it can be supported by B and run for reaping.

Next, left and right side clutch/brake 8A,
The 8B structure will be explained. A pair of left and right crawler traveling devices 7A, 7B are transmission-coupled to the tips of traveling shafts 10A, 10B extending laterally to the side of the mission case 9, and are connected to left and right side clutches/brakes 8A installed inside the mission case 9. , 8B so that they can be operated selectively. The side clutches/brakes 8A and 8B are configured to be selectively operable.

Operating arms 11A, 11B are provided for the side clutches/brakes 8A, 8B, and these operating arms 11A, 11B are connected to the operating cylinder 12.
It is linked to A and 12B.

As shown in FIG. 1, the left and right side clutch brakes 8A, 8B have input gears 13 loosely fitted into opposing portions of left and right running shafts 10A, 10B which are arranged abuttingly so as to be relatively rotatable. On both sides of the input gear 13, there are left and right operation sleeves 14A, 1 that can freely engage and release the clutch of the input gear 13.
4B is slidably fitted onto the running shafts 10A and 10B with splines, and is further connected to the input gear 1 by a spring 15.
The left and right operating sleeves 14A, 14B biased in the occlusal direction with the operating sleeve 14A,
Brake cases 17A and 17 fitted onto 14B
Frictional multi-plates 16a and 16b are provided between the input gear 13 and the left and right operation sleeves 14.
A and 14B form side clutches 8a and 8b, and the brake cases 17A and 17
B and the operation sleeves 14A, 14B form hand brakes 16A, 16B.

Next, the structure of the operating cylinder 12A will be explained.
As shown in FIG. 2, a cylinder case 18 is attached to the side wall of the mission case 9, and a piston 19 that can penetrate the side wall of the mission case 9 and enter the internal space of the mission case 9 is installed inside the cylinder case 18. There is. This piston 19 has a small diameter portion 19A located within the large diameter space of the cylinder case 18.
and a large diameter portion 19B that is positioned and tightly fitted inside the small diameter space of the cylinder case 18.
The mission case 9 is biased outward by a spring 20 fitted to the outside of the transmission case 9. The piston 19
This small diameter part 1 is located at the position corresponding to the tip of the small diameter part 19A.
An operating arm 11A is provided which swings when the tip of the operating arm 9A comes into contact with the operating arm 11A, and is linked via a shift fork to shift and drive the operating sleeves 14A and 14B. Hydraulic pipes 21 and 22 are connected to the cylinder case 18, the one 21 on the side of the transmission case 9 is a bias oil passage, and the one 22 on the outside with respect to the transmission case 9 is a supply oil passage 22 communicating with the pump P. It is configured.

The hydraulic circuit structure for the side clutches and brakes 8A and 8B will be explained. As shown in FIG. 1, pressure oil from the hydraulic pump P is supplied to the left and right operating cylinders 12A, 12B via a 3-position switching solenoid valve 23 serving as a switching control valve, and is also supplied to the left and right operating cylinders 12A, 12B through the bypass oil passage 21. be discharged.
Drain oil passage 3 connected to the bypass oil passage 21
2. On the way, there is an on-off valve 24 and a variable relief valve 2.
5 are interposed in series, and when the on-off valve 24 is opened, the side clutches 8a and 8b are in the off state, and when the on-off valve 24 is closed, the side brakes 16A and 16B are in the on state, and
By adjusting the variable relief valve 25, the input operating force to the handbrakes 16A, 16B is varied. Therefore, as shown in FIG. 1, when the switching operation cylinder 12A is supplied with oil by the switching control valve 23 and the on-off valve 24 is opened, the oil is drained through the bypass oil passage 21, so that the piston 1
9 is operated only up to a position corresponding to the bypass oil passage 21, and the side clutches 8a, 8b are disengaged. Now, when the variable relief valve 25 is gradually tightened, the piston 19 starts operating again.
Increase the braking force. Further, when the on-off valve 24 is closed alone, the piston 19 is operated all at once to the brake 16A operating position.

The operation structure for the side clutches and brakes 8A and 8B will be explained. For automatic steering control, a pair of left and right sensor bars 26 are provided on the grass divider support rod 1.
26, a sensor bar 26 for the accumulated grain culm,
Based on the contact detection of 26, the sensor bar 26 that touched
The control valve 23 is switched in order to steer the vehicle in the direction opposite to the direction in which the vehicle is present, so that only the side clutches 8a and 8b are used for steering. On the other hand, when the steering operation is performed manually, there are two methods: an operating lever 27 method and a side clutch/brake pedal 28A, 28B method, which will be explained below. With the control lever 27 method,
An operating lever 27 that swings left and right is provided, and the first swing of the operating lever 27 disengages the side clutches 8a, 8b, and the subsequent swing of the second stage releases the side clutches/brakes 8A, 8B. Two large and small electrode plates 29A, 29 shown to be activated
B, 30A, 30B are provided, and these large electrode plates 2
9A, 29B are electrically connected to the switching control valve 23, and the small electrode plates 30A, 30B are connected to the start valve 24.
It is electrically connected to. In the side clutch/brake pedal 28A, 28B system, sensors 31A, 31B are provided to detect depression of the side clutch/brake pedals 28A, 28B, and the sensors 31A, 31B are electrically connected to the switching control valve 23. Therefore, when someone depresses the side clutch/brake pedals 28A, 28B, the switching control valve 23 is actuated to switch the side clutches 8a, 8b to the disengaged state, and the side clutch/brake pedals 28A, 2
8B is mechanically linked to the variable relief valve 25, and the side clutch/brake pedal 28
By adjusting the amount of depression of A and 28B, the amount of restriction of the variable relief valve 25 is varied and the side brake 16 is
The operating forces of A and 16B are made variable.

In addition, 33 in the figure is an accumulator, and a modulating valve may be used instead of this accumulator.

[Another example]

This type of side clutch brake structure may also be applied to other agricultural vehicles or general vehicles.

[Brief explanation of the drawing]

The drawings show an embodiment of the hydraulic side clutch/brake according to the present invention, FIG. 1 is a configuration diagram showing the connection between the side clutch/brake and the operating system via the hydraulic system, and FIG. A sectional view, FIG. 3 is a plan view showing a transmission case and a crawler traveling device, and FIG. 4 is a side view of the combine harvester. 8A, 8B...Side clutch/brake, 8
a, 8b...Side clutch, 12A, 12B...
...Operation cylinder, 16A, 16B...Handbrake, 21...Bypass oil path, 23...Control valve, 25...Variable relief valve, 24...Opening/closing valve, 32...Drain oil path.

Claims (1)

[Claims] 1 Left and right side clutches/brakes 8A, 8B
Left and right operation cylinders 12 provided respectively for
A control valve 23 is provided to switch the pressure oil supplied to the operating cylinders 12A and 12B.
A bypass oil passage 21 from which the supplied pressure oil can be extracted is connected to each of 12B, and the connecting position of the bypass oil passage 21 to the operation cylinders 12A, 12B is set so as to be connected to both the operation cylinders 12A, 12.
An on-off valve 2 is provided in the middle of the drain oil passage 32 connected to the bypass oil passage 21, and is set at a position corresponding to the side clutch disengagement position in the middle of the piston stroke of B, and is capable of switching the drain oil passage 32 on and off.
4 and a variable relief valve 25 are arranged in series.