JPH0646884B2 - Front-back attitude control device for ground work machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front-rear posture control device for a ground work machine such as a rotary or plow connected to a tractor.
When hoisting the working part of the ground work machine while rotating, or to reduce the longitudinal inclination of the ground work machine in order to control the forward and backward tilt of the ground work machine in order to improve the flight performance and the plowing performance during the plowing work, In the front-rear posture control device configured to check and expand and contract the top link so that the universal joint shaft for power transmission between the tractor and the ground work machine can be safely rotated in each extension operation. ,
It proposes a control device devised so that the expansion and contraction operation of the toplink can be performed finely.

Conventional technology In order to secure a sufficient lifting height or to improve plowing performance, the length of the top link is controlled to expand and contract by manual or automatic operation, and the front-back direction with respect to the tractor of the ground work machine is controlled. A work implement lifting / lowering control device for controlling the posture is known from Japanese Patent Laid-Open No. 59-14710.

The working part of the ground work machine is driven by a universal joint shaft connecting the PTO shaft of the tractor and the input shaft of the ground work machine. The bending angle will change depending on the lifting height and the posture in the front-rear direction, and if it becomes too large, troubles such as damage to the joint pin will increase rapidly. It is necessary to make sure that the bending angle of the joint is within a safe range when the link is extended or retracted. However, since the conventionally known control device does not have such a confirmation means, there is a risk that the bending angle becomes excessive. Further, when the length of the top link is controlled to be expanded and contracted by a manual operation, the inertia of the ground work machine is large, and thus it is difficult to finely adjust the length of the top link by ordinary means.

Problems to be Solved by the Invention The present invention solves the problem that the bending angle of the universal joint shaft is too large and is not checked due to the hoisting height of the ground work machine and the inclination angle in the front-rear direction. In such a front-rear posture control device, the top-bottom posture of the ground work machine is appropriately controlled by finely adjusting the expansion and contraction of the top link length.

Technical Means for Solving Problems The present invention has taken the following technical means in order to solve the above problems.

That is, a ground work machine provided so as to be vertically movable to a tractor through a three-point link mechanism having an extendable top link is provided so as to be driven by a universal joint shaft connected to a PTO shaft of the tractor. In the longitudinal direction attitude control device of the machine, the length of the top link corresponding to the allowable bending angle of the universal joint shaft is stored in the storage unit of the microcomputer,
In addition, this stored content has at least two types of standard 3P and special 3P modes, and has a control means configured to expand and contract the top link according to the mode connected to the microcomputer. It is a characteristic front-back posture control device for a ground work machine.

Embodiment and Action Next, one embodiment of the present invention will be described with reference to the drawings. Fourth
As shown in the figure, on the rear part of the tractor (1), a rotary tiller as an example of the ground working machine (2) is attached to the pair of left and right lift arms (3), (3), and the left and right lift rods (4), The left and right lower links (5) and (5) swinging up and down via (4) and the three-point link mechanism (7) consisting of the upper center top link (6) are connected, and these three points are connected. The link mechanism (7) is moved up and down by a hydraulic lifting mechanism that lifts and lifts the lift arms (3), (3) by a lift cylinder (8) using hydraulic pressure. The top link (6) is formed by the top link cylinder (9) and the piston (9a) so that it can expand and contract,
By controlling the supply and discharge of the pressure oil of the oil pump to the toplink cylinder (9) by the operation of the expansion and contraction drive unit (10) composed of something like an electromagnetic switching valve, the ground work machine (2) The lower link (5) (5) will rotate in the front-rear direction with the connecting pins (11) (11) at the rear part of the lower link (5) (5) driving the working part (12) such as the tiller of the ground working machine (2). For this purpose, the PTO shaft (13) of the tractor (1) and the input shaft (14) of the ground work machine (2) are connected by a universal joint shaft (15).

Bending angle (α) of the universal joint shaft (15) with respect to the PTO shaft (13) and bending angle (β) of the universal joint shaft (15) with respect to the input shaft (14)
As shown in FIGS. 6 (a) and 6 (b), the value varies depending on the lifting height of the ground work implement (2) with respect to the tractor (1) and the posture in the front-rear direction. It has been found that α = β should be set as the condition that the shaft (15) can be rotated most smoothly with the least occurrence of an unreasonable force at the joint portion, and that this is the most desirable standard curve (At) and They are shown as (Ah). Then, the upper limit safety curves (St ₂ ) and (Sh ₂ ) and the lower limit safety curves (St ₁ ) and (Sh ₁ ) at which the universal joint shaft (15) can rotate sufficiently safely are shown in FIG. They are shown in (b).

Here, FIG. 6 (a) shows the tractor (1) as shown in FIG.
Lift arm in the case of a special 3P link in which the top link (6) is attached via the top link bracket (17) at a lower position of the top link mounting frame (16) and behind it. The relationship between the angle (θ) and the top link length (L) is shown, and although illustration is omitted in FIG. 6 (b), it is located above the mounting position of the special 3P link and in front of it. Lift arm in the case of a standard 3P link in which the top link (6) is mounted at a position (for example, directly mounted at a high position of the top link mounting frame (16) without using the top link bracket (17) in FIG. 4) Angle (θ)
And the toplink length (L).

Then, an inclination angle sensor (for example, such as a rotary potentiometer for detecting a lift arm angle (θ) as an inclination angle in the front-rear direction with respect to the tractor (1) of the ground work implement (2) ( S ^θ ) is provided and the toplink (6)
For detecting the length of the lift arm angle (θ) input from the inclination angle sensor (S ^θ ) by providing a top link sensor (S ^l ) such as a linear movement type potentiometer. Based on the above, in the calculation means (19) of the control unit (18) which is shown in the control block diagram of FIG. 1 and is composed of, for example, a micro computer, the standard top link length () for each lift arm angle (θ) Ls), safety toplink length (Lmin), and (Lmax) should be calculated. That is, the calculating means (19) has standard curves (At), (Ah), safety curves (St ₁ ), (St ₂ ), (Sh ₁ ), (Sh) shown in FIGS.
₂ ) are memorized respectively and either the special 3P link or the standard 3P link is designated in advance by the 3P link mode switching switch (Sm), so it corresponds to the detected lift arm angle (θ). The standard toplink length (Ls) and the like to be output are output from the calculation means (19) and are input to the correction means (20) in the next stage.

The correction means (20) includes a top link length (L) from the top link sensor (S ^l ) and a top link length correction switch provided near the driver seat (24) as illustrated in FIG. 7. (S
Input the correction instruction value (△ L) by ₁ ) and the extension and contraction instruction value (△ ^l ) by the toplink extension / contraction step switch (S ₂ ) respectively, and set the target toplink length (top) to be controlled of the toplink (6). La) is calculated. That is, the top link length correction switch (S ₁ ) functions only when the top link control switching switch (S ₃ ) is automatically switched, and the standard touch switch at that time is selected according to the operating position. The correction instruction value (ΔL) of (±) for the link length (Ls) is input to the correction means (20).

The top link extension step switch (S ₂ ) functions regardless of the switching position of the top link control switching switch (S ₃ ), and the neutral position shown in FIG. If it is tilted to the on position of (+), on the contrary, if it is tilted to the on position in the direction of the arrow Y, (-) is instructed.
If it is repeated once in the X direction, it is three times as much as one operation.
The expansion / contraction instruction value (Δ ^l ) of (+) is configured to be input to the correction means (20), and the correction means (20) has a top chart as shown as a flow chart in FIG. If the link control switching switch (S ₃ ) is manual, the target top link length (La) is the expansion / contraction extension value (△ ^l ) obtained by the top link expansion / contraction step switch (S ₂ ) and the current top link length.
If you only add to (L), operate the top link expansion / contraction step switch (S ₂ ) and then hold it in the neutral position as it is, the expansion / contraction instruction value (△ ^l ) so far will be added as (-). The target toplink length (La) is returned to the original value by acting on.

That is, one pulse of which the pulse length is set in advance is generated by the on / off operation of the top link expansion / contraction step switch (S ₂ ), and the correction means (20) after the fall of this pulse, If the trailing edge is delayed for a certain period of time, a pulse-like output having a length proportional to the number of on / off operations is output as the expansion / contraction instruction value (Δ ^l ), while the top link expansion / contraction step switch ( S
If hold ₂₎ in the off position beyond the predetermined time, stretch instruction value (△ ^l) is Yes as the 0, the target shoulder stop link length in this case is (La) is to be the Ls + △ L The control block diagram for this is 1
An example is illustrated in FIG. Whether the PTO axis (13) is being used is detected by the PTO axis sensor (S ₄ ) and PT
When the O-axis (13) is not used, the target top link length (La) = L + ΔL. When the PTO axis (13) is used, the correction instruction value (△ L) and the extension instruction value (△ ^l ) by the top link length correction switch (S ₁ ) and the top link expansion / contraction step switch (S ₂ ) are set. The target toplink length (La) is added to the standard toplink length (Ls), and the extension and contraction indication value (△) up to that time is maintained by maintaining the neutral position of the toplink extension and extension switch (S ₂ ). ^l )
Will be canceled.

And the target toplink length obtained in this way
(La), the safety toplink length (Lmin), (Lmax), and the toplink length (L) are input to the comparison command means (21), and the target toplink length (La) is the safety toplink length. (Lmin) to (Lmax) is checked, and if it falls outside this range, the target safety link length (La) is corrected to the nearest safe safety link length and When the top link length (L) is out of the safety top link length (Lmin) to (Lmax), a command to stop the PTO shaft (13) is issued when the PTO automatic cutoff switch is turned on. It is output to the drive unit (22) and a command is given from the comparison command unit (21) to the telescopic drive unit (10) in order to match the top link length (L) with the target top link length (La). is there. The elevating instruction of the ground work implement (2) is instructed by the elevating position setter (I ₁ ) as a target lift arm angle corresponding to the indicated height, for example, and the lift arm angle (θ) coincides with this. The comparison command unit (21) instructs the lifting drive unit (23) to do so.
Standard top-link length (L
s), the safety toplink length (Lmin) is not immediately indicated (Lmax), but one scale angle, for example, 1 °, is added or subtracted from the current lift arm angle (θ) toward the target lift arm angle. The selected intermediate target lift arm angle is selected, the intermediate standard top link length and the intermediate safety top link length corresponding to the intermediate target lift arm angle are calculated, and the correction and control described above are performed based on these. In order to avoid sudden expansion and contraction control of the toplink (6), and when the lift arm angle (θ) approaches the target lift arm angle up to a certain value, the comparison command unit
For example, a pulse-like command is given from (21) to, for example, an electromagnetic switching valve of the expansion / contraction drive unit (10), and the expansion / contraction operation of the top link (6) is decelerated, and the flexible joint shaft (15) is broken. The sharp fluctuations of the angles (α) and (β) are avoided.

The control block diagram of Fig. 1 also shows the basic configuration of the automatic tilling resistance control and the automatic tilling depth control, but in addition, the left and right posture control of the ground work machine (2) can also be used at the same time. Further, in the figure, auxiliary circuits such as AD and DA converters are omitted. In addition to the lift arm (3) described above for detecting the inclination angle of the ground work machine (2) with respect to the tractor (1), a weight attached to the ground work machine (2) or
Various methods such as a method for detecting the front-rear tilt of the lower link (5) can be used.

Effect of the Invention The front-rear posture control device for a ground work machine according to the present invention is configured as described above, and each tilt angle in the front-rear direction of the ground work machine (2), that is, for each vertical position, Safety top link length (Lmi
The length of the toplink (6) is always maintained within (n) to (Lmax) due to excessive bending angles (α) and (β) before and after the universal joint shaft (15). Trouble such as breakage of the joint part will be resolved, and the top-and-bottom expansion / contraction step switch (S ₂ ) will be turned on / off with almost no rest so that the expansion / contraction instruction value (△ ^l ) is added to the standard top-link length (Ls) to control the length of the top-link (6), so the target top-link length (La) can be finely adjusted according to the number of on-off operations. And moreover, it will be possible to give accurate instructions,
Since there is no inaccuracy such as a change in the instruction length due to the variation of the ON-holding time like a normal switch, it is possible to accurately perform the front-rear direction posture of the ground work machine (2).

Also, if the toplink extension switch (S ₂ ) is held in the off position, the extension instruction value (△ ^l ) added earlier will be removed and the original target toplink length (La) will be restored, so work to the ground The restoration operation after the attitude control of the aircraft (2) was extremely easy.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a control circuit block diagram, FIG. 2 is a control flow chart, FIG. 3 is a detailed view of an essential part of FIG. 1, and FIG. 4 is a side view in a working state. , Fifth
FIG. 6 is an explanatory view showing the inclination of the universal joint shaft, FIGS. 6 (a) and 6 (b) are characteristic views showing the desired length of the top link, and FIG. 7 is a perspective view of the main part of the tractor. Explanation of symbols (1) …… Tractor, (2) …… Ground work machine (5) …… Lower link, (6) …… Toplink (13) …… PTO shaft, (15) …… Universal joint shaft (20 ) …… Correction means (S _θ ) …… Inclination angle sensor (La) …… Target toplink length (Ls) …… Standard toplink length (S ₁ ) …… Toplink length correction switch (Lmin) , (Lmax) …… Safe Toplink Length

Claims (1)

[Claims] 1. A ground work machine which is vertically movable to a tractor through a three-point link mechanism having an extendable toppi link, is provided so as to be driven by a universal joint shaft connected to a PTO shaft of the tractor. In the attitude control device for the front-rear direction of the ground work machine, the length of the top link corresponding to the allowable bending angle of the universal joint shaft is stored in the storage unit of the microcomputer. At least two types of 3P and special 3P modes, and a front-back posture of the ground work machine characterized by having control means configured to expand and contract the top link according to a mode connected to the microcomputer. Control device.