JPH0347329A - Skid steer loader - Google Patents

Abstract

PURPOSE:To enable running to be properly controlled with safety by arranging a rotary encoder, a change-over switch, a signal correction device, a comparator, a change rate limiter, and function generators, together with a joystick and a lever position converter. CONSTITUTION:By a signal correction device 22, a dead zone is set, and the neutral position of set lever position signal(position signal) is enlarged, and is detected by a comparator 42, and switched to control for setting to zero the rotational frequency of a wheel detected by a rotary encoder 18, running is certainly stopped. Besides, the change of the position signal is suppressed by a change rate limiter 23, and when the multiplication value of the position signal is equal to or less than a fixed value, then the change of the signal is suppressed by an upper or lower limit limiter 28, and sudden start, sudden stop, sudden swing, and the like are prevented from being generated, and a vehicle is prevented from falling down. Besides, with function generators 31 - 33, characteristic between a lever position and a motor cylinder 15 is easily changed by the selection of a change-over switch 19, and a low speed area is enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cargo handling vehicle capable of super-interlining rotation (turning on the spot);
In other words, it relates to skid steer loaders.

2. Description of the Related Art As a conventional skid steer loader, for example, the one described in Japanese Patent Application No. 63-214287 has been proposed.

This skid steer loader basically consists of a vehicle body, two traveling devices installed on the vehicle body, and two driving devices that operate each traveling device.
It consists of two travel hydraulic drive devices, two cargo handling devices installed on the vehicle body, and two cargo handling hydraulic drive devices that operate each cargo handling device. An electric control device is provided to control one travel hydraulic drive device and two cargo handling hydraulic drive devices.

Problem to be Solved by the Invention 2 However, in conventional skid steer loaders, the neutral position of the multi-directional lever switch device is a point. There was a problem in that the wheels would not stop even if the directional lever switch device was returned to the neutral position.

The multi-directional lever switch device has a short operating force and a short stroke, and a small force or movement produces a large command signal. There was a problem with the vehicle turning and causing a risk of falling.

Furthermore, since the output signal of the multi-directional lever switch device is generally an electrical signal proportional to the stroke, there is a problem in that the multi-directional lever switch device cannot change the running characteristics.

The present invention solves the problems caused by adopting the multi-directional lever switch device, and an object of the present invention is to provide a skid steer loader that is equipped with a multi-directional lever switch device and can perform safe and accurate travel control. That is.

Means for Solving the Problems In order to solve the above problems, the present invention provides a vehicle body, two traveling devices installed in the vehicle body, two traveling hydraulic drive devices for operating each traveling device, and an fc2 driving device installed in the vehicle body. A skid steer loader comprising two cargo handling devices and two cargo handling hydraulic drive devices for operating each cargo handling device, the skid steer loader comprising: a multi-directional lever switch device for travel control of the traveling device; and an operation signal for the multi-directional lever switch device. ft conversion means for converting into a target lever position signal of each of the two left and right traveling hydraulic drive devices;
two rotational speed detection devices that detect the rotational speed of each of the traveling devices; a signal correction device that widens the forward/reverse neutral position of the target lever position signal; and an output signal of each of the signal correction devices that adjusts the neutral position. and two detecting means for detecting that the rotation speed of each traveling device is controlled by operating the respective detecting means to drive each of the travel hydraulic drive devices using the rotation speed signal of each of the rotation speed detection devices as a feedback signal. A skid steer loader according to a second aspect of the invention is further provided with a multi-directional lever switch device for controlling the travel of the traveling device, and a control means for controlling the multi-directional lever switch device to zero. a conversion means for converting a signal into a target lever position signal for each of the two left and right travel hydraulic drive devices; two change rate limiting means for respectively limiting changes in the target lever position signal; and each of the change rate limiting means. Upper and lower limit limiting means are provided for multiplying the output signals and limiting the upper and lower limits of each output signal when the multiplied value is below a certain value.

Furthermore, the skid steer loader of the third invention includes a multi-directional lever switch device for controlling travel of the traveling device, and an operation signal of the multi-directional lever switch device is transmitted to a target lever of each of the two left and right travel hydraulic drive devices. It is provided with a conversion means for converting into a position signal, a characteristic changeover switch capable of switching in multiple stages, and a characteristic change means for changing the characteristic of each target lever position signal according to the operation signal of the characteristic changeover switch described in fcIII. It is.

Effect: With the configuration of the first invention, the neutral position of the target lever position signal for forward and backward movement is widened by providing the signal correction means, and by detecting this neutral position, the rotational speed of the traveling device is inputted as a feedback signal. The skid steer loader is reliably stopped by reducing the number of revolutions of the traveling device to zero, and thus by setting the multi-directional lever switch device to a substantially neutral position.

Further, according to the configuration of the second invention, the change in the target lever position signal is suppressed by the change rate limiting means, and the multiplication value of each target lever position signal is equal to or less than a certain value, that is, each target V-par position signal has a different sign. When a lever operation is performed to perform a super-interlining turn with a large absolute value, the upper and lower limits of the target lever position signal are limited. Therefore, sudden starts, sudden stops, and sudden turns are prevented.

Further, according to the configuration of the third invention, the characteristics of the target lever position signal change according to the operation input signal of the characteristic changeover switch, and for example, the low speed range of the multi-directional lever switch device can be expanded.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a side view of a skid steer loader showing an embodiment of the present invention, and FIGS. 2 and 3 are a block diagram of a principal part of a traveling control system and an electric control device of the same skid steer loader.

The skid steer loader 1 is a cargo handling vehicle that is capable of super interlining turning using independent left and right running devices.As shown in FIG. 1, an operator sits in a driver's seat 3 protected by a head guard 2 Equipped with a seat bar 4 for protection in the event of a collision,
By operating two multi-directional lever switch devices (hereinafter referred to as joysticks) 5, a traveling device (described later) is driven and self-propelled, and a cargo handling hydraulic drive device (cylinder) is operated.
The container 7A and boom 3 are driven by 6A and 6B to perform cargo handling.

The traveling device (traveling drive system) will be explained.

As shown in Fig. 2, the engine 8 is controlled so that its rotational speed remains constant according to the actuation amount of the accelerator lever 9, and the rotational force of the engine 8 is controlled by the left and right H5T (hydrostatic transmission) pump IOL. , I
The OR and vane pump 11VC are transmitted, and the left and right H5T bonders IOL and IOH convert the hydraulic oil into high-pressure fluid and drive the left and right hydraulic drive motors 12L and 12, respectively.
The left and right wheels 13 are driven by the drive torque taken out by the hydraulic drive motors 12L and 12RK.
L and 13R are driven independently.

HST pump IOL, IOR has 7 tearing levers and 14L.

The position of 14R determines the direction and amount of hydraulic oil discharged from the neutral position, and the steering v y<
-14L e The running direction and speed of the skid steer loader 1 are controlled by the operation of 14R. Steering levers 14L and 14R are each electric cylinders 15L.

Driven by 15R and steering lever 14L.

The position of the steering lever 14R is controlled by the electric control device 16 via these electric cylinders 15L and 15R, and the positions of the steering levers 14L and 14R are fed back to the electric control device @16 by potentiometers 17L and 17R, respectively.

Further, the rotational speeds of the hydraulic drive motors 12L and 12R, that is, the rotational speeds of the wheels 13L and 13R, are detected by rotary encoders 18L and 18R, respectively, and are fed back to the electric control device 16.

In addition, by operating the joystick 5 for traveling, as shown in Fig. 4, the direction of the lever is determined and the stroke is determined so that the traveling speed is determined. The X coordinate and the Y coordinate indicating the forward/backward direction and speed are input to the electric control device 16.

Furthermore, an operation signal of a changeover switch 19 for selecting one of the three driving characteristic modes shown in FIG. 5 is input to the electric control device 16.

The electric control device 16 will be explained based on the block diagram of FIG.

The operation input signal of the joystick 5 is sent to the lever position converter 2.
1, left and right steering levers 14L,
14R are converted into respective target lever position signals.

The lever position converter 21 calculates and outputs a left target travel lever position signal R and a right target travel lever position signal R using the following equations (1) and (2).

L=y+x (however, -A≦L≦A) ・(1
)R=y−x(fc, -8≦R≦A) (2) A is a positive limit value.

The control of the right electric cylinder 15R based on the right target lever position signal R will be described below. The same applies to the left target lever position signal.

The target lever position signal R is input to a signal corrector 22R having the characteristics shown in FIG. 6, the neutral position for forward and reverse movement is widened, and the signal is input to a change rate limiter 23R.

The rate of change limiter 23R controls the target lever position signal, which is the positive input of the adder 24R, and the current fX (output signal of the rate of change limiter 23R), which is the minus input of the adder 24R, even if the difference is large. Even if the value suddenly changes, the input of the integrator 25R is suppressed by the upper limiter 26R1 and the lower limiter 27R to prevent the current value from changing suddenly. When the difference between the target value and the current value falls within the limit values of the upper limiter 26R and lower limiter 27H, the rate of change limiter 23R becomes a first-order lag function. The absolute value of the target lever position signal whose rate of change is limited by the rate of change limiter 23R is limited by the upper and lower limiters 28R.

The limit value of the upper and lower limiter 28R is determined by multiplying the left and right current values by the multiplier 29, and then using the function generator 30 to set the 7th value according to the next order.
It is generated as shown in the figure. That is, when the left and right current values have opposite signs and a large absolute value, that is, when performing super-interlining turning, the limit value is made small to limit the speed of super-interlining turning.

The target lever position signal output from the upper and lower limiter 28R is converted into a target electric cylinder position signal by selected function generators 31R, 32R, and 33R. Function generator 3
The selection of 1R, 32R, and 33R is performed by the mode switch 34 into which the operation signal of the changeover switch 19 is input.

As shown in the WJS diagram, the characteristics of the function generators 31R, 32R, and 33R are a linear normal mode, a downward quadratic curve low speed mode, and a linear ultra low speed mode. The characteristics of the hydraulic pump discharge flow rate (electric cylinder position) from the pump IOR are changed.

The deviation of the target electric cylinder position signal from the actual electric cylinder position signal of the potentiometer 17R is taken by an adder 35R, and the signal is inputted to the drive unit 37R through a PID controller 36R'), and the electric cylinder 15R is driven so that the deviation becomes zero. be done.

Also, the rotation of the rotary encoder 18R of the wheel 13R (
The counter 38R converts the detection signal into the number of revolutions, and the function generator 39R shown in FIG.
The deviation is taken at R and the PID controller is detected, and the companion comparator 42R switches the output to the PIDID controller 36 output and inputs it to the drive unit 37R. Cylinder 15R is driven.

With the above configuration, six cine bands are provided in the signal corrector 22.
As a result, the neutral position of the target lever position signal is expanded 9, and when this neutral position is detected by the comparator 42, the control is switched to zero the rotation speed of the wheel 13 detected by the rotary encoder 18. Cylinder 15, HST pump 10
Even if the characteristics of the hydraulic drive pump 12 change, the rotation of the wheels 13 can be stopped by setting the joystick 5 to a substantially neutral position, and the traveling can be stopped reliably.

Furthermore, if a sudden change in the target lever position signal occurs, the rate of change limiter 23
This prevents sudden starts and stops even if the joystick 5 is operated greatly, and furthermore, when the multiplication value of the left and right target lever position signals is less than a certain value, the upper and lower limiters 28 suppress the absolute value. It is possible to prevent sharp turns and prevent the vehicle from overturning.

In addition, the lever position and w are determined by function generators 31, 32, and 33.
The characteristics with the lvJ cylinder 15 can be easily changed by selecting the changeover switch, and the low speed range can be expanded.

In this embodiment, the changeover switch 19 is shown to be attached to the spring N, but it can also be attached to the grip of the joynut 5 or the side of the brake pedal.

Function generator with volume 31.32.33
It is also possible to continuously change the first-order coefficient or the second-order coefficient.

Effects of the Invention As described above, according to the present invention, by providing the signal correction means, it is possible to widen the neutral position of the target lever position signal, and by detecting this neutral position, the rotation speed of the traveling gear can be adjusted as a feedback signal. By inputting this as input and setting the rotation speed of the traveling device to zero, even if the characteristics of the traveling hydraulic drive device change, the skid steer loader can be reliably stopped by setting the multi-directional lever switch device to the almost neutral position. can.

Further, according to the second invention, the change in the target lever position signal is suppressed by the change rate limiting means, and the multiplication value of each target lever position signal is equal to or less than a certain value, that is, each target lever position signal has a different sign and an absolute value. When a lever operation that performs a large super-centering turn is performed, by limiting the lower limit of the target lever position signal, sudden starts, sudden stops, and sudden turns can be prevented, and the vehicle can be prevented from overturning. I can do it.

Furthermore, according to the 39th invention, by changing the characteristics of the target lever position signal according to operation input No. 2 of the characteristic changeover switch, the driving characteristics can be changed, such as expanding the low speed range of the multi-directional lever switch device. be able to.

[Brief explanation of drawings]

The drawings show one embodiment of a skid steer loader according to the present invention; Fig. 1 is an external side view, Fig. 2 is a schematic diagram of the main parts of the travel control system, and Fig. 3 is a block diagram of the electric control device. , Fig. 4 is an explanatory diagram of the Joyce Dick signal, Fig. 5 is a plan view of the switching switch, Fig. 6 is a characteristic diagram of the signal corrector, and Figs. 7 to 9 are characteristic diagrams of the function generator. be. 1...Skid steer loader, 5...Multi-directional V)<
- Switch device, 6... Cargo handling hydraulic drive device, 7A...
・Packet (cargo handling device), 7B... Boom (cargo handling device), 8... Engine, 10... HST pump, 12
...Hydraulic drive pump, 13...Wheel, 14...Nutearing lever, 15...Electric cylinder, 16...
・Electric control device, 17... Potentiometer, 18.
...Rotary encoder ([lff1a detection device), 1
9... Selector switch.

Claims (1)

[Claims] 1. A vehicle body, two traveling devices provided on the vehicle body, two traveling hydraulic drive devices that operate each traveling device, two cargo handling devices provided on the vehicle body, and operating each cargo handling device. The skid steer loader is equipped with two cargo handling hydraulic drive devices, including a multi-directional lever switch device for controlling the traveling of the traveling device, and an operation signal of the multi-directional lever switch device for controlling the traveling of the two left and right traveling devices. A conversion means for converting into a target lever position signal of the hydraulic drive device, two rotation speed detection devices for detecting the rotation speed of each of the traveling devices, and a signal correction means for widening the neutral position of the target lever position signal for forward and backward movement. and two detection means for detecting that the output signal of each of the signal correction means is at the neutral position, and the operation of each of the detection means causes the rotation speed signal of each of the rotation speed detection devices to be used as a feedback signal for each of the travels. A skid steer loader comprising a control means for driving a hydraulic drive device and controlling the rotational speed of each traveling device to zero. 2. A vehicle body, two traveling devices provided on the vehicle body, two traveling hydraulic drive devices that operate each traveling device, two cargo handling devices provided on the vehicle body, and two cargo handling hydraulic drive devices that operate each cargo handling device. A skid steer loader comprising: a multi-directional lever switch device for controlling travel of the traveling device; and an operation signal of the multi-directional lever switch device for controlling target lever positions of the two left and right travel hydraulic drive devices. A conversion means for converting into a signal, two rate-of-change limiting means for respectively limiting changes in the target lever position signal, and an output signal of each of the rate-of-change limiting means are multiplied, and when this multiplied value is less than a certain value, A skid steer loader provided with upper and lower limit limiting means for respectively limiting the upper and lower limits of each output signal. 3. A vehicle body, two traveling devices provided on the vehicle body, two traveling hydraulic drive devices that operate each traveling device, two cargo handling devices provided on the vehicle body, and two cargo handling hydraulic drives that operate each cargo handling device. The skid steer loader is equipped with a multi-directional lever switch device for controlling travel of the traveling device, and an operation signal of the multi-directional lever switch device for controlling the target lever position of each of the two left and right traveling hydraulic drive devices. A skid comprising a conversion means for converting into a signal, a characteristic changeover switch capable of changing in multiple stages, and a characteristic change means for changing the characteristics of each target lever position signal according to an operation input signal of the characteristic changeover switch. steer loader.