JP2508817Y2 - Lifting control device for working unit in agricultural tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a lifting / lowering control device for a working unit in an agricultural tractor, which is formed by connecting a working unit to a traveling machine body so that the working unit can move up and down.

[Problems to be Solved by Prior Art and Invention] Generally, in this type of agricultural tractor, when working parts such as a rotary and a plow are connected to perform ground work, a working part raising operation, a steering turning operation,
It is necessary to continuously perform braking operation of the wheels on the turning side, steering wheel return operation, work part lowering operation, etc. in a short time, which makes the operation complicated and requires considerable skill. It was a problem.

Therefore, it has been proposed to provide a turning detection sensor that detects the turning of the machine body and an automatic lifting control mechanism that simplifies the operation during turning by automatically moving the working unit up and down based on the detection. In the conventional type, since the turning detection sensor switches to the non-detection state during the steering wheel return operation performed during turning, it is permissible that the working unit lowers during turning, or at the start of turning and the end of turning. Since the working part position is greatly displaced as shown in FIG. 9,
The headlands could not be arranged in an orderly manner, and the accuracy of work on the ground was a problem.

On the other hand, in order to provide such an automatic raising / lowering control mechanism, it is necessary to secure a dedicated space, and when it is connected to the operation lever, another problem arises in that the operation lever cannot be interrupted.

[Means for Solving the Problems] The present invention was devised with the object of providing a lifting / lowering control device for a working unit in an agricultural tractor that can eliminate these drawbacks in view of the above circumstances. Draft detection operation that automatically raises the working unit that is vertically movable to the traveling machine body and that can be moved up and down by manual operation of the operating lever based on the detection of an abnormal pulling load from the working unit without affecting the lever position of the operating lever. An agricultural tractor with a mechanism is provided with an automatic lifting control mechanism that automatically raises the working unit based on the detection operation of the turning detection means that detects the turning of the machine body, and automatically lowers the working unit when non-detection operation is performed. At this time, the automatic lifting control mechanism is caused to perform an automatic working part lowering operation based on the non-detection operation of the turning detection means by a predetermined time after the non-detection operation of the turning detection means. It is characterized in that the descending operation delay means for extending the automatic raising / lowering control mechanism is provided in the draft detecting operation mechanism so that the operation lever can be interrupted.

The present invention, with this configuration, can improve the operability of the agricultural tractor and the ground work accuracy.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, 1 is a traveling vehicle of an agricultural tractor,
A working unit 3 such as a rotary is movably connected to a rear portion of the traveling machine body 1 via an elevating link mechanism 2, and the working unit 3 swings a lift arm 5 according to an extension / contraction operation of a hydraulic cylinder 4. Up and down by, but these configurations are all conventional.

Reference numeral 6 denotes an operation lever provided on the side of the driver's seat 7 for raising and lowering a working unit, and the operation lever 6 is a hydraulic case 8
Is swingably supported in the front-rear direction and is connected to a valve link 9a of a hydraulic valve 9 which is a control valve of the hydraulic cylinder 4 via a link mechanism (not shown). That is, the swing of the operating lever 6 is converted into the forward / backward movement of the engagement pin 10 that engages with the lower end side of the valve link 9a, and the valve link associated with the forward / backward movement of the engagement pin 10
The hydraulic valve 9 is switched (raised, neutral, lowered) by the swinging of 9a and the protruding and retracting of the valve rod 9b.

On the other hand, reference numeral 11 denotes a feedback padlock whose rear end is connected to the lift arm 5 side so as to move back and forth as the working unit 3 moves up and down, and at the front end of the feeding padlock 11.
The tip of the arm 12 is pierced so that it can move back and forth,
An ammunition machine 11b is provided for elastically urging the tip of the arm 12 toward the locking nut 11a. The base end of the arm 12 is pivotally supported so as to swing with the forward and backward movement of the feed back bridge 11, and the engagement pin 12b provided on the projecting piece 12a protruding from the base end is the bubble link 9a. Is engaged with the upper end side of the. That is, the feed back mechanism constituted by the feed back bridge 11 and the like moves the work unit 3 up and down based on the operation of the operation lever 6 when the work unit 3 reaches the height corresponding to the position of the operation lever 6. Is configured to stop by switching the hydraulic valve 9 to the neutral state.

Further, 13 is a draft detection rod, the draft detection rod 13 is connected to a top link bracket 13 having a detection function to detect an abnormal traction load, and the detection operation of the draft detection rod 13a is linked to the link 14 , 1
By being transmitted to the arm 12 via 5 and 16, automatic raising control of the working unit 3 based on the abnormal traction load detection is performed, but the rear position of the link 16 will be described later. Solenoid 17 is provided, and solenoid 17
The projecting operation allows the arm 12 to swing through the link 16 against the ammunition 11b to raise the working unit 3, and when the immersing operation is performed, The working portion 3 is lowered by allowing the automatic return swing of the arm 12 by the urging force of the machine 11b. Incidentally, 50 is a draft control lever.

Still further, 18 is a turning detection sensor, and the turning detection sensor 18 is configured to detect and operate when the steering angle of the front wheels exceeds a predetermined angle based on the operation of the tie rod 20 in the front wheel steering mechanism 19. The sensor 18
The detection signal of 1 reaches the solenoid 17 through the automatic switching switch 21 and the timer 22. That is, the working unit 3 is detected based on the turning detection of the turning detection sensor 18.
On the other hand, when the turning detection sensor 18 is switched to the non-detection state, the working unit 3 is automatically lowered when the turning detection sensor 18 is switched to the non-detection state.
A delay timer is configured to turn off the solenoid 17 after a predetermined time elapses without immediately turning off the solenoid 17 when the turning state is switched from the turning detection state to the non-detection state.

Further, 23 is a transmission case, and the transmission case 23 includes a front case 23a in which the main clutch 24 is housed, a center case 23b in which the drive shaft 25 and the front drive shaft 26 are housed, and a transmission mechanism 27. The front case 23a is a light-pressed product, and its rear edge is bolted 28a to the front end face of the center case 23b and the front end face. Bearing holder 28
It is attached to the center case 23b, which is a cast product, by being sandwiched between and.

Further, 29 and 30 are pipes vertically arranged in the center case 23b in the front-back direction. The drive shaft 25 is inserted through the upper pipe 29 and the front drive shaft is inserted through the lower pipe 30. 26 is inserted. In other words, both pipes 29 and 30 should be
It is configured as a circulation oil passage that circulates the lubricating oil in both cases 23a and 23c through the 23a and the rear case 23c.

Furthermore, 31 is a plurality of main transmission gears that are spline-fitted to the rear end portion of the drive shaft 25, and these main transmission gears 31 are selectively meshed with a driven gear 33 on the main transmission shaft 32 side. Power transmission to the main transmission shaft 32 is carried out by a transmission gear for spline-fitting the transmitted power to the auxiliary transmission shaft 34.
35 transmission directly or via ultra-low speed gear 36 transmission gear
By selecting whether to transmit to 35, it is possible to perform ultra-low speed shifting. On the other hand, 37 is the main transmission gear
The output gear 37a of the back idler gear 37 is a sleeve idler gear that can be meshed with the main gearbox 31. Power transmission is performed via.
That is, the power transmitted to the back idler gear 37 is directly transmitted to the auxiliary transmission shaft 34 without passing through the ultra-low speed transmission mechanism.

Further, 39 is a center differential provided in the front drive shaft 26, and the center differential 39 is a pair of pinion gears 41 provided on the differential case 40 via the pinion shaft 40a, and a pair of side gears meshing with both the pinion gears 41. 42, 43, a pair of pretensioning rings 44 that receive a torque from the pinion shaft 41a and move forward and backward when a rotational difference occurs between the side gears 42, 43, depending on the pressing force received from the pretensioning ring 44. A so-called limited slip differential gear is configured by a member such as a friction plate 45 that generates frictional resistance between the side gears 42 and 43 and the differential case 40. And the center differential 39 is a differential case
Drive side front drive shaft 26a integrally connected to 40
Power is input to the driven front drive shaft 26b that is integrally connected to the side gear 42, while power is input and output automatically to the front wheels according to the running state. You can do it. That is, the drive speed of the front drive shaft 26 is set to be slightly slower than the rear wheel drive speed, and during normal traveling including turning, the driven rotation of the driven front drive shaft 26b drives the driven front drive shaft 26a. Since the friction plate 45 does not operate after winning the rotation, the front wheel driving force is transmitted to the idling side gear 43 to drive the two wheels. On the other hand, when the rear wheels slip, the driving rotation of the drive-side front drive shaft 26a exceeds the driven rotation of the driven-side front drive shaft 26b.
The side gears 42, 43 rotate integrally with the differential case 40 due to the operation of the compression ring 44 and the friction disc 45 based on the rotation difference of the four wheels, and the front wheel driving force is transmitted to the driven front drive shaft 26b as it is and four-wheel drive traveling It is about to do.

In the embodiment of the present invention configured as described above, when the traveling machine body 1 during ground work reaches the headland and the worker starts the turning operation accordingly, the working unit 3 detects the turning detection sensor 18 based on the detection. Will rise immediately. On the other hand, the operator performs a steering operation return operation before the completion of turning, but the turning detection sensor 18
Even if is switched to the OFF side, the working unit 3 is not lowered immediately based on the detection, and the turning is completed as shown in FIG. 9, and the working unit 3 is lowered until it reaches a predetermined tilling start position. Will delay the start of.

As described above, in the case where the present invention is implemented, the working unit 3 is automatically moved up and down based on the detection of the turning detection sensor 18, so that the operation during turning can be simplified. In spite of this, the automatic lowering operation of the working unit 3
It is delayed until the turning is completed and the working unit 3 reaches the predetermined tilling start position. Therefore, it is possible to solve the conventional inconvenience that the working unit 3 descends before the turning is completed or before reaching the tilling start position, and as a result, orderly headland alignment can be automatically performed, Ground work accuracy can be significantly improved.

Moreover, since the solenoid 17 is provided in the draft detection mechanism that automatically controls the raising of the working unit 3 on the basis of the abnormal traction load detection, the operation lever 6 does not directly interlock with the operation lever 6. Permitting interrupt operations, it is extremely easy to secure a mounting space, and retrofitting to conventional models can be done easily.

Further, since the automatic switching switch 21 for switching the automatic raising / lowering control of the working unit 3 to the manual mode at the time of turning the machine body is provided, there is no fear of causing any trouble when the work which cannot be handled by the automatic raising / lowering control is performed.

In the present embodiment, the front case 23a is
Since the front end face of the center case 23b and the center case 23b which is sandwiched and fixed between the bearing holder 28 and the center case 23b are made of separate press products, the weight can be significantly reduced as compared with the integrally cast product. Rika can also be improved in assembly workability.

In addition, the upper and lower pipes 2 arranged side by side in the center case 23b
Drive shaft 25 and front drive shaft 26 on 9 and 30, respectively
Since the structure is inserted, the lubricating oil filled in the front case 23a and the rear case 23c can be circulated to prevent deterioration of the lubricating oil as much as possible.

Further, since the reverse power transmission path which does not pass through the ultra-low speed transmission mechanism is configured, it is possible to dispense with an operation for canceling the ultra-low speed especially during the reverse operation during the ultra-low speed work, so that the operability can be remarkably improved.

Further, a limited slip type center diff 39 is provided in the front drive shaft 26 to automatically switch between two-wheel and four-wheel drive according to the running condition, so that the drive switching operation by a lever is unnecessary. The simplification can be achieved, and optimal traveling can be performed according to the traveling situation.

The present invention is not limited to the above-mentioned embodiment, but it is also possible to add, for example, a turning angle detection sensor, a traveling speed detection sensor, etc., and change the delay time based on these sensor values. And, in this case, the working accuracy can be further improved.

[Effects] In summary, since the present invention is configured as described above, the automatic lowering operation of the working unit is performed while the working unit is automatically raised and lowered based on the detection of the turning detection means. This is not immediately after the switching operation of the detection means to the non-detection side, but is delayed by a predetermined time. Therefore, by setting the delay time to the time when the turning is completed and the working unit reaches the predetermined tilling start position, the working unit descends before the turning is completed or before the tilling start position is reached. It is possible to solve the conventional inconvenience that it is caused, and it is possible to automatically perform orderly headland alignment and improve work accuracy.

Moreover, as a result of the automatic lift control mechanism being provided in the draft detection operation mechanism, the interrupting operation of the operation lever is not restricted unlike the one linked with the operation lever, and the operability is improved. In addition, the space for installing the draft detection operation mechanism can be secured and the mounting space can be secured, which contributes to downsizing.

[Brief description of drawings]

1 is a side view of a tractor, FIG. 2 is a side view of a lifting operation mechanism, and FIG. 3 is a side view of a lifting operation mechanism according to an embodiment of the present invention.
Fig. 4 is a block diagram of the automatic lifting mechanism. Fig. 4 is a sectional view of the essential parts of the transmission case. Fig. 5 is a sectional view of the essential parts of the same.
FIG. 6 is a cross-sectional view of a main part showing a speed change mechanism, FIG. 7 is a power transmission circuit diagram showing a main part of a power transmission mechanism, FIG. 8 is a cross-sectional view of a center differential, and FIG. 9 is a tractor for explaining the operation. It is a top view. In the figure, 1 is a traveling body, 3 is a working unit, 17 is a solenoid, 18
Is a turning detection sensor, and 22 is a timer.

Claims (1)

(57) [Scope of utility model registration request] 1. A working unit, which is vertically movable and is movable up and down by a manual operation of an operating lever, automatically raises a working unit regardless of a lever position of the operating lever when an abnormality in a towing load from the working unit is detected. An agricultural tractor equipped with a draft detection actuation mechanism automatically raises the working part based on the detection operation of the turning detection means that detects the turning of the machine body, and automatically raises and lowers the working part when non-detection operation is performed. In providing the mechanism, the automatic lifting control mechanism is provided with descending operation delay means for delaying the automatic working part lowering operation based on the non-detection operation of the turning detection means by a predetermined time from the non-detection operation of the turning detection means. In an agricultural tractor characterized in that an automatic lifting control mechanism is provided in the draft detection operation mechanism so that an interrupt operation of an operation lever can be performed. Business section of the elevator control system.