JPS63279975A - Turning speed regulator for skid steering vehicle - Google Patents

Abstract

PURPOSE:To regulate turning optimally even when a vehicle turns with zero or low driving speed by controlling the driving amount of right and left driving wheels corresponding to vehicle speed. CONSTITUTION:Cam plate actuators 9, 10 are provided to cam plate type liquid pressure pumps 4, 5 for driving drive wheels such that right and left liquid pressure motors can be controlled by varying the angle of the cam plates. Relative cam plate angle alphaO of variable capacity pumps 4, 5 allowable for vehicle speed V is stored previously in a computer 16. Relative cam plate angle alphaS corresponding to the lever angles thetaR, thetaL or right and left levers 18, 17 is obtained then vehicle speed is obtained based on an engine speed and an average cam plate angle thereafter relative cam plate angle alphaO allowable for the vehicle speed is obtained. Difference between right and left cam plate angles is controlled to exceed over a predetermined level if the relative cam plate angle alphaS is larger than the allowable relative cam plate angle alphaO, so as to achieve optimal turning condition corresponding to vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a turning speed regulating device for a skid steer vehicle.

(Prior Art) In a skid steer vehicle, the left and right drive wheels can be independently controlled from maximum forward rotation, through neutral (stop), to maximum reverse rotation by operating the left and right control levers.

Due to its structure, it was possible to make sharp turns while driving forward or backward, in which case the vehicle would receive a sudden shock and would also be at risk of falling. In order to prevent this, for example,
There is a technique disclosed in Japanese Patent No. 131466. That is, the steering bar is connected with an appropriate amount of play between the left and right operating levers, and the difference in lever angles of the operating levers (lever relative angle) is regulated within the play range.

(Problem to be solved by the invention) However, since the permissible lever relative angle is uniquely determined, there remains the problem that maneuverability is reduced when turning on the spot or turning at low speeds. has been done.

An object of the present invention is to solve the above-mentioned problems and provide a turning speed regulating device for a skid steer vehicle that can optimally control turning without reducing maneuverability even when turning on the spot or turning at low speeds. It's about doing.

Structure of the Invention (Means for Solving Problems) In order to achieve the above-mentioned object, the present invention includes a right side operation amount detection means for detecting the operation port of the right side operation means, a stone side drive means for driving the right side drive wheel. , comprising: a left side operation amount detection means for detecting the operation amount of the left side operation means; and a left side drive means for driving the left drive wheel; A skid steer vehicle configured to control right and left drive means, comprising: a vehicle speed detection means for detecting vehicle speed; and a storage means for storing data of an allowable difference between the drives of the right and left drive wheels corresponding to the vehicle speed. , drive regulation control means for regulating and controlling the right and left drive means so that the vehicle speed is within the allowable range based on the data of the then allowable drive port difference between the two drive wheels stored in the storage means based on the vehicle speed detected by the vehicle speed detection means; The gist of the present invention is a turning speed regulating device for a skid steer vehicle, which is equipped with the following.

(Function) With the above configuration, the drive regulation control means adjusts the right and left drive wheels so that the vehicle speed is within the allowable range based on the vehicle speed detected by the vehicle speed detection means and the data of the difference between the drives of the two drive wheels that is allowable at that time in the storage means. Regulate and control means. the result,
Turning speed is regulated according to vehicle speed.

(Example) An example embodying the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of the drive system of a tire-type skid steer vehicle, in which left and right drive means for driving left and right drive wheels 1 and 2 are driven by an engine 3 as a prime mover. a right-hand variable pump 4.5 and a left-hand and right-hand hydraulic motor 6 drive-coupled to each drive wheel 1.2;
．． 7, the hydraulic motor 6.7 is a variable displacement pump 4.
．． 5 and transmits its rotational force to the drive wheels 1 and 2 via a sprocket 8a and a chain 8b. This variable displacement pump 4,5
In this embodiment, a swash plate type hydraulic pump is used, and the same pump 4
, 5 are operated to change the angle of the swash plates, the forward/reverse direction and rotation speed of the left and right hydraulic motors 6.7 are controlled.

Note that the prime mover is the engine 3 in this embodiment, but is not limited to this, and may be an internal combustion engine or an external combustion engine.

Anything can be used as long as it can drive the driving means, such as an electric motor. Further, the variable displacement pumps 4 and 5 may be of the oblique shaft type.

In this embodiment, the swash plate actuators 9, 10 are embodied in left and right hydraulic cylinders 11, 12, as shown in FIG. That is, two poppet valves 13a, 13b, 14a, 14b are arranged in the hydraulic oil piping to each hydraulic cylinder 11, 12 for changing the angle of the swash plate. Further, the piston rods 11a and 12a whose tips are drivingly connected to the swash plates of the left and right variable displacement pumps 4 and 5, respectively, are provided with left and right side Rondo position detection devices 15a for detecting their positions.
.

15b is arranged.

And poppet valves 13a, 13b, 14a.

14b are respectively swash plate angle signals E1. E2
When the poppet valve 13a is inputted, the poppet valve 13a is activated based on the signal.
, 13b, 14a, 14b (7) Opening m is performed intermittently to change the ratio of the open state of the valve in unit time.
So-called duty control is performed. Through this duty control, the supply of the hydraulic oil sucked up from the tank T by the pump P and stored in the accumulator A to the hydraulic cylinders 11 and 12 is controlled.
1a and 12a are moved to a predetermined position at a predetermined moving speed.

That is, when one poppet valve 13a, 14a is closed and the other poppet valve 13b, 14b is driven to open and close intermittently at a predetermined speed, hydraulic oil is supplied to the rod chambers 11b, 12b of the hydraulic cylinder, and the piston rods 11a, 12a is moved to the right in FIG. 2 at a predetermined speed. Conversely, when one poppet valve 13b, 14b is closed and the other poppet valves 1 to 13a, 14a are intermittently driven to open and close at a predetermined speed, the hydraulic fluid flows into the rod chamber 11b of the hydraulic cylinder.
12b and the screws 1 to 11a of the bottom chambers 11G and 12C.

The piston rods 11a and 12a move to the left in FIG. 2 due to the different pressing area ratios to the piston rods 12a, and the piston rods 11a move at a predetermined speed by adjusting the flow rate of hydraulic oil accompanying the opening and closing operations of the poppet valves 13a and 14a. , 12a
will be moved. At this time, the detection signals C1 and C of the rod position detection devices 15a and 15b that detect the position
2 is fed back to the microcomputer 6 and stopped at a predetermined position.

Further, as shown in FIG. 1, there are left and right operating levers 17.1 provided on the driver's seat as left and right operating means.
8 is a left and right side operation amount detection device 19.20 consisting of a potentiometer as a means for detecting left and right side operation.
are provided, respectively, and a manipulated variable signal SG1 . It is designed to output SG2. Although potentiometers are used as the operation m detection devices 19 and 20 in this embodiment, they are not limited to potentiometers, and may be, for example, inductance type displacement meters or variable vowel type displacement meters.

Roughly speaking, an engine rotation speed sensor 21 as vehicle speed detection means is arranged on the output shaft of the engine 3.
The engine rotation speed is detected at 1, and the engine rotation speed detection signal Se is output from the same sensor 21.

Next, the electrical configuration of this swing speed regulating device will be explained based on FIG. and the CPU 22 uses the ROM
Various processes are executed according to control programs stored in 23. The CPU 22 also includes a readable and rewritable memory (hereinafter referred to as RAM) 2.
4 is connected, and various calculation results of the CPU 22 are temporarily stored in the RAM 24.

Further, the CPU 22 is connected to the left operating star detection device 19, the right operating amount detection device 20, the left rod position detection device 15a, the right rod position detection signal 15b, and the engine rotation speed sensor 21 through the input circuit 25. Operation amount signal SG1 from each device. SG2. A rod position detection signal C1°C2 and an engine rotation speed detection signal Se are respectively input.

Then, the CPU 22 receives the operation amount signal SGI.

The operation amount (lever angle) of the left and right operation levers 17 and 18 is detected by SG2. That is, positive and negative lever angles 0R1et<θR is the right lever angle, and e[ is the left lever angle) are detected when the operating levers 17 and 18 are pushed forward and pulled toward the front. Furthermore, CPU22
Hydraulic cylinder 1 is detected by rod position detection signals @C1 and C2.
1. The rod position of 'i2 is detected, and the rotation speed of the engine 3 is detected based on the engine rotation speed detection signal Se.

Further, each poppet valve 13a, 13b, 14a, 14b is connected to the CPU 22 via a drive circuit 26, and the CPU 2
2 is each poppet valve 13a, 13b.

14a and 14b, the swash plate angle signal E1. ．． It is designed to output E2.

The ROM 23 also stores the allowable swash plate relative angle of the swash plate type variable displacement pump 4°5 for the vehicle speed V shown in FIG. (difference between the two) αO is stored in advance. That is,
The figure (a) shows that the allowable swash plate relative angle αO is linearly inversely proportional to the vehicle speed ■, and the figure (b) shows that the allowable swash plate relative angle αO is constant until a constant vehicle speed v1; The above is linearly inversely proportional, and in the same figure (C), the allowable swash plate relative angle αO is constant up to a constant vehicle speed v2, and at a constant vehicle speed V
If it is 2 or more, it is inversely proportional to the curve. In this embodiment, Fig. 4(C) is used, but Fig. 4(a)
Alternatively, it is also possible to select and use the image shown in FIG.

And CPU22, RAM24. ROM 23, input circuit 25 and drive circuit 26 to microcomputer 16
is configured.

Next, the operation of the swing speed regulating device configured as described above will be explained based on the flowcharts shown in FIGS. 5(a) and 5(b).

The CPU 22 detects the left and right lever angles eR, eL (step 1), and multiplies the lever angles eR, eL by a coefficient a to obtain the left and right swash plate angles αR-2α corresponding to the lever angles eR, eL. [Calculate - (Step 2). Next, the CPU 22 calculates the left and right swash plate angle α obtained in this way.
Step 3) Calculate the relative swash plate angle αS by finding the absolute value of the difference between R=, α[-, and further calculate the swash plate angle αR′
, αL-, thereby calculating the average swash plate angle value αN (step 4).

Further, the CPU 22 multiplies the engine speed N at that time by the average swash plate angle value αN obtained as described above and the coefficient B to obtain the vehicle speed V at that time (step 5).
Step 2 is to calculate the allowable swash plate relative angle α0 for the vehicle speed V obtained in this way based on the data in FIG. 4(C).Step 6)
Compare with S (step 7).

As a result, when the swash plate relative angle αS is smaller than the allowable swash plate relative angle α0 (αs less than α0), the CPU 22 changes the left and right swash plate angle αR−1α[′ to the swash plate angle αR2α[(α
R=αR−2α[=αE″), step 8), and left and right swash plate angle signals are output (step 9).

Further, the CPU 22 receives the result of the comparison in step 7,
Swash plate relative angle αS is less than allowable swash plate relative angle α0−b <αS≧
αO), then the left and right swash plate angle αR-.

α[- is compared (step 10). As a result, if the right swash plate angle αR' is larger than the left swash plate angle α['(αR'≧α[-), the CPU 22 determines the left and right swash plate angle α
R1α[ is calculated using the following equation (step 10).

αR = αN + (αO/2) ... (1) αL = αN
-(αO/2)- (2) After that, the CPU 22 outputs the same left and right swash plate angle (αR1αL) signals (step 9).

Further, as a result of the comparison in step 10, the CPU 22 determines that if the right swash plate angle αR' is smaller than the left swash plate angle α['(αR'-<α['>), the left and right swash plate angle αR1α[ Calculate using the following formula (step 12) αR=αN-(αO/
2) ...(3) α[=αN+(αO/2) ・
...(4) In that case, the CPU 22 adjusts the left and right swash plate angles (αR
1αL) signal is output (step 9).

Therefore, when the swash plate relative angle αS is greater than or equal to the allowable swash plate relative angle α0, the left and right swash plate angles αR1α [the larger of the swash plate angle average αN and the value 1/2 of the allowable swash plate relative angle αO The left and right swash plate angles are determined by adding 1/2 of the allowable swash plate relative angle αO to the smaller average swash plate angle αN, and the difference between the left and right swash plate angles is determined as the allowable swash plate relative angle. It is limited to an angle αO. That is, in the above equations (1) to (4), the relative angle 1αR-α[! is αO due to (1)−(2>
And, according to (3)-(4), αO is within the range of allowable swash plate relative angle (=αO).

Then, the CPU 22 adjusts the poppet valve 13a so that the left and right swash plate angles αR1α[ outputted in step 9 become the swash plate target value by feedback control according to the interrupt routine shown in FIG. 5(b).

13b, 14a, and 14b are duty-controlled.

That is, the CPU 22 inputs the left rod position detection signal C1 and detects the rod position (swash plate angle) at that time (step 13).
), the difference between the left swash plate target value (left swash plate angle αL) and the left rod position is calculated (step 14), and the poppet valve 1
Calculate the duty ratio of 3a and 13b (step 1
5). Further, the CPU 22 inputs the right rond position detection signal C2, detects the rod position at that time (swash plate angle), and calculates the difference between the right swash plate target value (right swash plate angle αR) and the rod position. At the same time (step 17), the duty ratio of the poppet valves 14a, 14b is calculated (step 18). After that, CPJJ22 each poppet valve 13a
, 13b, 14a, 14b are outputted with swash plate angle signals El and E2. By repeating this routine, the target swash plate angle is controlled and the left and right drive wheels 1 and 2 are driven ff1.
Tl emperor is controlled.

In this way, in this embodiment, the allowable swash plate relative angle αO is set in advance according to the vehicle speed, and the left and right operating levers 17
．． Determine the swash plate relative angle (difference in angle) αs with respect to the lever angles eR and eL of 18, determine the vehicle speed ■ from the engine rotation speed N and the average swash plate angle value αN, and determine the allowable swash plate relative angle αO for the vehicle speed V. , when the swash plate relative angle αS is greater than or equal to the allowable swash plate relative angle α0, the difference between the left and right swash plate angles is calculated by adding or subtracting 1/2 of the allowable swash plate relative angle αO to the average swash plate angle αN. The relative angle of the swash plate is within the allowable relative angle αO.

Therefore, with conventional mechanical turning speed regulation methods, maneuver control was poor when turning on the spot or when turning at low speeds, but this does not occur and the optimum swash plate angle can be set according to the vehicle speed. It is possible to ensure safety at high speeds and perform optimal turning regulation while ensuring maneuverability even when turning in the field or turning at low speeds.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and may be implemented as shown in FIG. 6, for example.

That is, after calculating the allowable swash plate relative angle αO in steps 1 to 6 as in the above embodiment, the mechanical swash plate relative angle limit value α is calculated.
max is calculated (step 7).

This is because, as shown in FIG. 7, a line L1 indicating the limit value αmax of the mechanical swash plate relative angle with respect to the vehicle speed V is obtained in advance, and the CPU 22 determines the limit value of the mechanical swash plate relative angle by obtaining the vehicle speed V. The value αn'+ax can be calculated. This limit value αmax is also inversely proportional to the vehicle speed V. In addition, in FIG. 7, L2 indicates the data of the allowable swash plate relative angle αO shown in FIG. 4(C).

Then, the CPU 22 compares the left and right swash plate angles αR-2α[- in step 8), and as a result, when the right swash plate angle αR' is larger than the left swash plate angle α[-, it is calculated as described above. Based on the limit value αmax of the mechanical swash plate relative angle, the left and right swash plate angles αR2α[ to be output are calculated using the following equation (step 9).

cl = cl + (α0 /2) ・(αs /αm
ax )...(5) aL = aN - kuao /2) φ (αs
/amax)...(6) After that, the CPU 22 outputs the same left and right swash plate angle signals (
Step 10).

Further, the CPU 22 receives the result of the comparison in step 8,
When the right swash plate angle αR' is smaller than the left swash plate angle αF-, the left and right swash plate angle αR is output based on the mechanical swash plate relative angle limit value αmax determined as described above using the following formula.
2α[ is calculated (step 11).

αR=aN −(ao/2) Fist(αs/αmax
)...(7) αL=αN+(αO/2)・(αS/αl11ax)・
(8) After that, the CPU 22 outputs the left and right swash plate angle (αR9α[) signals (step 10).

In this embodiment, the difference (relative angle) between the left and right swash plate angles to be output is αO・αS/αma according to the above equations (5)-(6).
x, and αO・αS by the above equations (7)-(8)
/αmax, and the allowable range (αO・αS/αmax
) is within.

Further, in this embodiment, unlike the limiter system, there is no problem in which the swash plate angle does not change even if the lever is moved in a region larger than the allowable relative angle, and the swash plate can be controlled over the entire lever angle range.

Further, in the above embodiment, the vehicle speed was determined using the engine rotation speed sensor 21, but the vehicle speed may also be calculated using sensors that detect the rotation speed of the left and right drive wheels 1 and 2, or a speed sensor such as a laser Doppler speedometer. The vehicle speed may be detected using a meter.

Effects of the Invention As detailed above, according to the present invention, the left and right drive wheels are driven according to the vehicle speed, so that maneuverability is not impaired even when turning on the spot or turning at low speed. It exhibits an excellent effect of being able to perform optimal turning regulation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a drive system of a skid steer vehicle embodying the present invention, FIG. 2 is a schematic diagram of a swash plate actuator,
Figure 3 is an electrical block diagram showing the electrical configuration of the turning speed regulating device, Figures 4 (a) to (C) are diagrams showing the allowable swash plate relative angle with respect to vehicle speed, and Figures 5 (a) and (b). 6 is a flowchart for explaining the action of the turning speed regulating device, FIG. 6 is a flowchart for explaining the action of the turning speed regulating device for scraping, and FIG. 7 is a diagram showing the relative angle of the swash plate to the vehicle speed. . 1 is a left drive wheel, 2 is a right drive wheel, 4 is a right variable displacement pump that constitutes a left drive means, 5 is a right variable displacement pump that is a right drive means, and 6 is a left hydraulic motor that is a left drive means. , 7 is a right hydraulic motor constituting the right drive means, 16 is a microcomputer as a drive regulation control means, 17 is a left operation lever as a left operation means, 18 is a right operation lever as a right operation means, and 19 is a left side operation lever. Right side operation amount detection device as operation port detection means, 20
is a right side operation amount detection device as a right side operation amount detection means, 2
1 is an engine rotation speed sensor as a vehicle speed detection means; 23
is a ROM as a storage means. Patent applicant Toyoda Automatic Loom Works Co., Ltd. Representative
Person Patent attorney On 1) Hironobu map (b) Vehicle speed (absolute value) V

Claims (1)

[Scope of Claims] 1. Right side operation amount detection means for detecting the operation amount of the right side operation means; right side drive means for driving the right drive wheel; left side operation amount detection means for detecting the operation amount of the left side operation means; , a skid steer vehicle comprising: a left drive means for driving a left drive wheel; and wherein the right and left drive means are controlled based on the operation amounts of the right and left operation means by the right and left operation amount detection means, a vehicle speed detection means for detecting vehicle speed; a storage means for storing data of an allowable difference in the drive amount of the right and left drive wheels corresponding to the vehicle speed; A turning speed regulating device for a skid steer vehicle, comprising drive regulation control means for regulating and controlling the right and left drive means so that the right and left drive means are within an allowable range based on data on a difference in the drive amount of both drive wheels.