JPH08164768A - Travel controller of working machine - Google Patents

Abstract

PURPOSE: To check oil temperature rise in a hydrostatic continuously variable transmission(HST) without lowering the relief pressure by operating an alarm at a time when a difference between setting revolution to be found out of shift operated variable information and actual outputting revolution exceeds the setting range. CONSTITUTION: A feedback control mans F so a controller 12 operates motor- driven cylinder 8 on the basis of each detection information of a rotational frequency detector 15 of an engine 3 and a first potentiometer 10 detecting the operating position of a shift lever 9 so as to make the setting revolution of an output shaft 4a to be set up by operation of the shift lever 9 and the actual outputting revolution of the output shaft 4a accord with each other. In addition, when a difference between the setting revolution of the output shaft 4a to be found out of shift operated variable information detected by a second potentio meter 21 detecting the operating position of a trunnion shaft 4t and the actual outputting revolution of the output shaft 4a has exceeded the setting range, an alarm 22 operates via a comparing control means H.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a combine harvester, rice transplanter,
Alternatively, the present invention relates to a traveling control device for a working machine including an HST for traveling such as a tractor, and more specifically, to a technique for recognizing that the hydraulic pressure of the HST does not become too high.

[0002]

2. Description of the Related Art There are a large number of HSTs (hydrostatic stepless transmissions) used as traveling transmissions. For example, in the lawn mower disclosed in Japanese Patent Application Laid-Open No. 5-106731, H
By adopting the ST, smooth shifting can be performed on the lawn without damaging the grass. In the HST, a relief valve (see FIG. 2 of the above publication) that operates when the circuit pressure becomes higher than a predetermined value is generally provided in the oil passage connecting the pump and the motor in order to protect the hydraulic circuit. is there.

[0003]

In other words, when the rice planter escapes from a wetland, or when an overload condition such as traveling on a super mud with a transport vehicle is reached, the internal pressure of the HST rises and the relief valve operates. This protects the hydraulic devices such that the seal part is not damaged. However, even if the relief operation state is continued, the oil temperature rises considerably, and some measures have been required. Further, recently, in order to improve the operation feeling, the transmission is driven by an actuator such as an electric motor, and only the switch control is required as the manual operation, so that the mechanical operation type traveling operation structure is improved. As described above, there is little opportunity to be aware that the operation of the shift lever is heavy and that the vehicle is in an overloaded state.

Therefore, it is conceivable to reduce the allowable value of the relief pressure so that the oil temperature does not become too high even if the relief operation state continues, but in that case, the relief blows as soon as the load becomes a little, and the work is performed. It is difficult to realize because it can be predicted that it will not happen. An object of the present invention is to make it possible to suppress an increase in the oil temperature of HST without lowering the relief pressure.

[0005]

To achieve the above object, the present invention provides a traveling HST, a speed change actuator capable of changing the speed of the HST, and a speed change operation tool for driving the speed change actuator. And an operation position detection means capable of detecting the operation position of the gear shift operation tool, and an output rotation detection means capable of detecting the rotation speed of the output shaft of the HST,
Feedback control for operating the gear shift actuator based on the detection information of both detection means so that the set rotation speed of the HST output shaft set by the operation of the shift operation tool and the actual output rotation speed of the HST output shaft match. Means and a shift position detecting means for detecting the shift operation amount of the HST, and the set rotational speed of the output shaft obtained from the shift operation amount information detected by the shift position detecting means and the actual output rotation of the output shaft. It is characterized in that it is provided with comparison control means for linking the shift position detecting means, the output rotation detecting means and the alarm device so that the alarm device is activated when the difference from the speed exceeds the set range.

[0006]

In the structure in which the gear shifting operation is performed by the gear shifting actuator, a control for detecting whether or not gear shifting is performed according to the command of the gear shifting operation tool and correcting the command according to the command when different from the command, so-called feedback control is performed. It is necessary to make it work, so that it becomes possible to normally operate the actuator drive operation type gear shifting operation which gives a light operation feeling.

Then, due to the function of the comparison control means, the HS
A shift position detecting means for detecting the shift operation amount of T is provided, and the difference between the set output speed of the output shaft obtained from the shift operation amount information detected by the shift position detecting means and the actual output rotation speed of the output shaft is Since the alarm device is activated when it exceeds the set range, for example, if the alarm device is set to operate at a pressure slightly lower than the relief pressure, it can be notified that the limit pressure will be reached soon. Therefore, the operator can easily take measures such as preparation for interruption of the overloaded traveling state. Also, if the alarm device is set to operate with the relief pressure, it can be immediately known that the relief operation has been activated, and the operation can be interrupted by temporarily stopping the operation or operating the auxiliary transmission mechanism at a low speed. The person can immediately take measures to reduce the running load and lower the oil temperature of the HST.

That is, if the HST output shaft issues a command to rotate but does not actually rotate, it means that the load is too large to drive the wheels. The state can be detected by the comparison control means. Since the comparison control means can perform processing based on a theoretical and actual HST rotation speed difference, that is, on an electric circuit, for example, there is a risk of leakage in a structure in which switching is performed by sensing a relief pressure. At the same time, the sensing condition must be reset every time the relief pressure is different, which is troublesome and unstable. On the other hand, the means of the present application allows the relief pressure setting to be changed by circuit adjustment. It is preferable because it can be formed and does not cause a leak due to the electrical detection structure.

[0009]

As a result, in the case where the actuator drive operation structure provides a light HST shift operability, it is possible to quickly know the overload state that is difficult to notice because the light operation is obtained, and the oil temperature rises. It was possible to provide a product that is easy to operate and has excellent reliability, which can be dealt with in advance to prevent problems such as overshooting.

[0010]

Embodiments of the present invention will be described below with reference to the drawings in the case of a rice transplanter, which is an example of a working machine. A rice transplanter is shown in FIG. 1, 1 is a four-link type lifting mechanism for vertically moving the planting device 2 with respect to the machine body 3, 3 is an engine,
Reference numeral 4 is a traveling HST (hydrostatic continuously variable transmission), 11 is a mission, 6 is a front wheel, and 7 is a rear wheel.

As shown in FIGS. 5 and 7, the engine 3 mounted on the front part of the machine body and the input shaft 4b of the HST 4 mounted on the front end of the mission 11 are interlocked via a transmission shaft 23. The mission 11 includes a traveling auxiliary transmission mechanism 24,
Rear wheel differential mechanism 25, inter-stock transmission mechanism 26, first PTO shaft 27 for planting device 2, and second PT linked to input shaft 4b
An O shaft 28, a front wheel drive shaft 29, etc. are provided.

As shown in FIG. 2, an electric cylinder 8 (corresponding to a speed change actuator) for shifting the trunnion shaft 4t of the HST 4 and a speed change lever (corresponding to a speed change operation tool) 9 for driving the electric cylinder 8 are commanded. , A first potentiometer (corresponding to an operation position detecting means) 10 capable of detecting the operation position of the shift lever 9, an output rotation detecting means A capable of detecting the rotation speed of the output shaft 4a of the HST 4, and an output rotation speed of the engine 3. Rotation speed detector (pickup etc.)
15 is connected to the control device 12 to form a travel control device. That is, the set rotational speed of the output shaft 4a set by operating the gearshift lever 9 of the engine 3 at a certain rotational speed (usually set to the maximum rotational speed by full accelerator) and the actual output rotational speed of the output shaft 4a. The control device 12 is provided with the feedback control means F for operating the electric cylinder 8 based on the detection information of the rotation speed detector 15 and the detection means 10 and A so that they coincide with each other.

As shown in FIG. 3, output rotation detecting means A
Is composed of a pickup sensor including an electromagnetic pickup 13 arranged near the output shaft 4a and a single magnetic metal cam 14 provided on the output shaft 4a. That is, as shown in FIG. 4, the rotational speed (rotation speed) can be detected by the number of protruding waveform portions a in the detection wave of the pickup sensor A per unit time.

For example, when the speed change lever 9 is operated to the forward operation range of the intermediate position between the neutral speed and the maximum forward speed, the rotational speed of the HST output shaft 4a is uniquely determined from the rotational speed of the engine 3 at that time (setting). Therefore, if the rotation speed of the output shaft 4a actually detected at that time is slower than the set speed, the feedback control means F causes the trunnion shaft 4t to operate further toward the forward high speed side. 8 to drive 8. Then, the driving of the electric cylinder 8 is continued until the detected rotation speed matches the set rotation speed.

Further, a rotation direction discriminating means B for discriminating the rotation direction of the output shaft 4a is provided, and when the HST output shaft 4a is rotating while the speed change lever 9 is in the neutral operation, the rotation speed thereof is made zero. Trunnion shaft 4t
The control device 12 is provided with the correction control means S in which the output rotation detection means A, the rotation direction determination means B, and the electric cylinder 8 are linked to each other in a state where is operated. The rotation direction discriminating means B is also configured by the above-mentioned pickup sensor A, and as shown in FIG. 3, the cam 14 has a curved shape in which one side is a substantially vertical raised surface and the other side is gently raised. One formed on the surface, that is, formed in an asymmetrical shape in the rotation direction of the output shaft 4a, the smooth ridge portion Na and the substantially vertical portion Sa in the detected waveform a shown in FIG. Whether the rotation direction is (or after) is determined according to whether the rotation direction is normal or reverse.

That is, the play of the connecting portion between the speed change lever 9 and the first potentiometer 10 and the HST 4 before shipment.
Due to factors such as an error in the neutral alignment operation of
Even if the speed change lever 9 is operated to the neutral position, if the output shaft 4a may rotate forward or backward at an extremely low speed, the output shaft 4a may be detected from the rotation speed detection information and the rotation direction detection information of the pickup sensor A. The rotation of 4a is controlled so as to stop.

Further, a second potentiometer (corresponding to shift position detecting means) 21 for detecting the operation position of the trunnion shaft 4t is provided, and the setting of the output shaft 4a obtained from the shift operation amount information detected by the second potentiometer 21 is provided. The comparison control means H that links the second potentiometer 21, the pickup sensor A, and the alarm device 22 so that the alarm device 22 operates when the difference between the rotational speed and the actual output rotational speed of the output shaft 4a exceeds the set range. Are provided in the controller 12. In other words, when the trunnion shaft 4t is fitted in a wetland, the load on the drive wheels is too large, the trunnion shaft 4t cannot travel even though it is operated forward, and the output shaft 4a does not rotate. The alarm device 22 such as a buzzer is activated to inform the operator that the load on the HST 4 is heavy.

As shown in FIG. 6, the HST 4 has a known structure in which a hydraulic circuit includes a variable displacement hydraulic pump 16, a hydraulic motor 17, a charge pump 18, a forward relief valve 19, a reverse relief valve 20 and the like. Is.

[Other Embodiments] It is premised that the working machine normally uses the engine at the maximum rotation speed.
The "engine speed detecting means 15" may be included in the "claims" as an essential component.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

[Figure 1] Side view of a riding rice transplanter

FIG. 2 is a system diagram showing a travel control device.

FIG. 3 is a front view showing the structure of a pickup sensor.

FIG. 4 is a diagram showing a detection waveform graph of a pickup sensor.

FIG. 5 is a side view showing a transmission structure of an engine and a mission.

FIG. 6 is a hydraulic circuit diagram of HST

FIG. 7 is a diagram showing the structure of a traveling mission.

[Explanation of symbols]

 4 HST 4a Output shaft 8 Shift actuator 9 Shift operating tool 10 Operating position detecting means 21 Shift position detecting means 22 Warning device A Output rotation detecting means

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[Procedure amendment]

[Submission date] July 26, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (1)

[Claims] 1. An HST (4) for traveling and this HST
A gear shifting actuator (8) capable of gear shifting operation (4)
A gear shift operation tool (9) for driving the gear shift actuator (8), an operation position detection means (10) capable of detecting the operation position of the gear change operation tool (9), and the HST.
(4) The output rotation detecting means (A) capable of detecting the rotation speed of the output shaft (4a), and the set rotation speed of the output shaft (4a) set by the operation of the shift operation tool (9). And feedback control means for operating the shift actuator (8) based on the detection information of the detection means (10) and (A) so that the actual output rotation speed of the output shaft (4a) matches. (F) is provided, a shift position detecting means (21) for detecting the shift operation amount of the HST (4) is provided, and the output obtained from the shift operation amount information detected by the shift position detecting means (21). When the difference between the set rotational speed of the shaft (4a) and the actual output rotational speed of the output shaft (4a) exceeds the set range, an alarm device (2
2) so that the shift position detecting means (21) is activated.
And the output rotation detecting means (A) and the alarm device (22)
A traveling control device for a working machine, comprising: a comparison control means (H) for linking with each other.