JPS61238551A - Inching control device - Google Patents

Abstract

PURPOSE:To perform inching operation under a constant operation feeling, by controlling brake force in accordance with loads exerted to a drive system. CONSTITUTION:A CPU 17 descriminates either one of no load, small load and large load conditions in accordance with detection signals from a slope detecting sensor 11 and a load detecting sensor 12. Further, the CPU 17 reads out a function D1 upon a no load condition, a function D2 upon a small load condition and a function D3 upon a large load condition from a memory device 18. Further, the CPU 17 indexes a duty in accordance with the depressing degreed of an inchining pedal 15 to control brake force.

Description

[Detailed description of the invention]

OBJECT OF THE INVENTION (Field of Technical Application) The present invention relates to an industrial vehicle such as a forklift truck equipped with an automatic transmission with a clutch, and more particularly to an inching control device that controls the engagement of a clutch during an inching operation. (Prior Art) Conventionally, for example, in a forklift truck equipped with an automatic transmission with a dry single-plate clutch, the clutch transmission 1-lux and braking force corresponding to the amount of depression of the inching pedal are as shown in FIG. It was uniquely determined by function B. That is, when the inching pedal is depressed, the brake drive means is operated to control the operating state of the brake in order to obtain a braking force uniquely determined by the amount of depression. (Problem to be Solved by the Invention) However, as mentioned above, the brake is uniquely determined by the amount of depression of the inching pedal, so for example, the amount of depression of the inching pedal when starting normally on a flat road is When attempting to start, there are problems in that the braking force decreases due to the amount of depression, and the starting time lag becomes large. Therefore, it is necessary to operate the inching pedal and adjust the amount of depression of the inching pedal in response to the difference in the load condition on the drive system of the forklift, such as starting on a flat road and starting on a slope. It was not possible to perform the inching operation with a constant operating feeling regardless of the load condition applied to the inching machine. An object of the present invention is to solve the above problems by controlling the braking force according to the load applied to the drive system of a vehicle, so that the inching operation can always be performed with a constant operation feeling regardless of the load condition applied to the drive system. To provide an inching control device that can Structure of the Invention (Means for Solving Problems) In order to achieve the above object, the present invention provides a brake drive means for operating the brake and controlling the braking state of the brake.

[In addition, load detection means for detecting the load state of the cargo handling vehicle and inching operation amount detection means for detecting the operation amount of the inching pedal are provided, and roughly speaking, the braking value of the brake with respect to the operation amount of the inching pedal is determined. The brake driving means is actuated based on an indexing means that determines the load condition of the cargo handling vehicle and a braking value determined by the indexing means to brake the brake to a predetermined braking force.
The gist of this invention is an inching control device which is equipped with a control means for controlling the winding. (Function) The indexing means 1 is based on the load condition of the cargo handling vehicle detected by the load detection means and the operation amount of the inching pedal detected by the inching operation amount detection means. The braking value of the brake with respect to the operation amount of the L inching pedal is determined according to the load state of the cargo handling vehicle. Based on the braking value determined by the determining means, the control means operates the brake driving means to control the brake to a predetermined braking force. (Embodiment) Hereinafter, a preferred embodiment in which the present invention is embodied in a forklift will be described with reference to the drawings. FIG. 1 shows the braking mechanism and electric block circuit of a forklift. Based on the depression of the brake pedal 1, hydraulic oil is supplied from the mask cylinder 2 to the wheel cylinder 4 via the first electromagnetic solenoid valve 3, and its operation is performed. Based on the oil supply, the pistons of the wheel cylinders 4 brake the forklift. Further, the wheel cylinder 4 is supplied with hydraulic oil from a power unit 6, which also serves as a brake driving means, via a second electromagnetic valve 5, which serves as a brake driving means, and the hydraulic pressure of the hydraulic oil, that is, The braking force is appropriately controlled based on switching control of the second electromagnetic solenoid valve 5. Then, the oil pressure is applied to the solenoid 5 of the second electromagnetic solenoid valve 5.
The excitation operation of a is determined based on the duty (t/TI) of the excitation signal SG1 shown in FIG. 2 as a braking value for exciting the solenoid 5a, and in this embodiment, as shown in FIG. The braking force relative to the hydraulic pressure of the hydraulic oil supplied to the wheel cylinder 4 is preset as shown in FIG. 4. Therefore, it can be seen that when the second electromagnetic solenoid valve 5 is driven and controlled by the excitation signal SG1 having a large duty, the oil pressure of the wheel cylinder increases and the braking force increases. Next, an electric circuit for controlling the first and second electromagnetic solenoid valves 3.5 will be explained. A slope detection sensor 111 serving as a load detection means is a sensor that detects the inclination of a forklift, and detects whether the forklift is traveling on a flat road or a slope. Similarly, the load oil pressure switch 12, which serves as a load detection means, is a switch that detects the oil pressure of the cargo handling hydraulic circuit, and is adapted to detect the presence or absence of a load. And this sensor 1
1 and the detection signals of the switch 12 are outputted to a central processing unit, which will be described later, via an input/output interface 13. Inching sensor 1 as inching operation amount detection means
A potentiometer 4 detects the amount of depression of the inching pedal 15 provided on the driver's seat 61, and the detected signal is digitally converted by an A/D converter 16 and output to the interface 13. A central processing unit (hereinafter referred to as CPU) 17 as an indexing means and a control means is connected to the input/output interface 1.
3, each sensor inputs a detection signal from the sensor, and operates according to a control program stored in a storage device 18. The CPU 17 determines the amount of depression of the inching pedal 15 based on the detection signal from the inching sensor 14, and determines the amount of depression of the inching pedal 15 based on the data of the amount of depression for the detection signal of the inching sensor 14 stored in advance in the storage device 18. It is about to be served. Further, the CPU 17 determines whether the forklift is on a flat road or a slope based on the detection signal from the slope detection sensor 11, and determines whether the forklift is in an unloaded state based on the detection signal from the loading oil pressure switch 12. Determine whether the vehicle is loaded or not. Therefore, the CPU 17 sets the brake force corresponding to the amount of inching pedal depression determined to be a flat road (hereinafter referred to as zero load state) to the function 81 shown in FIG. The solenoid 5a is excited and controlled so that the duty of the excitation signal SG1 for excitation control of the solenoid 5a of the electromagnetic solenoid valve 5 becomes a function D1 shown in FIG. Furthermore, when it is determined that the road is on a slope (hereinafter referred to as a small load state), the CPtJ17 adjusts the decote of the excitation signal SG1 of the solenoid 5a to the amount of depression in order to make the braking force for lifting the inching pedal into a function 82 shown in FIG. The solenoid 5a is energized and controlled so that the function D2 shown in FIG. 5 is achieved. Furthermore, when it is determined that the vehicle is on a slope and is in a loaded state (hereinafter referred to as a heavy load state), the CPU 17 sets the duty of the excitation signal SG1 of the solenoid 5a according to the amount of depression in order to set the braking force to the amount of depression of the imbunging pedal to the function 83. The solenoid 5a is excited and controlled so that - becomes the function D3. As is clear from FIG. 6, the functions 81 to B3 are such that, when the inching pedal depression amount is the same, the greater the load on the drive system of the forklift, the greater the braking force. Each of the functions D1 to B3 corresponds to each of the functions B1 to B3.
D3 is stored in advance in the storage device 18, and the duty of the excitation signal SG1 relative to the amount of pedal depression is calculated based on the read function. The CPU 17 uses the determined duty excitation signal S.
GI interface 13 and solenoid drive circuit 1
9 to the solenoid 5a of the second electromagnetic solenoid valve 5 to control the excitation of the solenoid 5a. Also, the solenoid 5 of this second electromagnetic solenoid valve 5
When outputting the excitation signal SG1 to the first electromagnetic solenoid valve 3, the CPU 17 outputs a switching excitation signal SG2 to the solenoid 3a of the first electromagnetic solenoid valve 3 via the interface 13 and the solenoid drive circuit 20, thereby controlling the mask cylinder 2 and the wheel cylinder. 77 to cut off the conduit between the two. Next, the operation of the forklift constructed as described above will be explained. Now, when the inching pedal 15 is depressed to start the forklift, the inching sensor 14 detects the amount of depression and outputs the detection signal to the CPU 17 via the A/D converter 16 and the interface 13. CPU
17 determines the depression ω of the inching pedal 15 in response to this detection signal. At the same time, CP (J17) switches to the solenoid 3a of the first electromagnetic solenoid valve 3 and outputs an excitation signal SG2 to switch the valve 3 and cut off the pipeline between the mask cylinder 2 and the wheel cylinder 4. Therefore, the hydraulic oil will not flow back into the mask cylinder 2 at this point. Also, the slope detection sensor 1 and the load detection switch 12 detect the state of the traveling road and the presence or absence of the forklift's load at this time. In other words, the load condition of the forklift is detected, and the detection signal is sent to the CP via the interface 13.
Output to U17. Based on the detection signals from the slope detection sensor 11 and the load detection switch 12, the CPU 17 determines what load state the forklift is currently in, that is, whether it is in a zero load state, a small load state, or a large load state. do. The CPU 17 uses function D1 when the load state is zero, function D2 when the load is small, and function D when the load is large.
3 is selected and read from the storage device 18. Then, the CPU 17 determines the duty of the excitation signal SG1 of the solenoid 5a for the maximum depression of the inching pedal 15 shown in FIG. 5, using the determined depression amount of the inching pedal and the selected function. Now, when the load is zero, the CPU 17 reads the function D1 from the storage device 18, and determines the duty of the excitation signal SG1 with respect to the amount of depression of the inching pedal 15 according to the function D1 shown in FIG. The CPU 17 then uses the determined duty via the interface 13 and the solenoid drive circuit 19.
The excitation signal SG1 is output to the solenoid 5a to switch the second electromagnetic solenoid valve 5 (duty control).
do. Therefore, the braking force corresponding to the amount of depression of the inching pedal 15 at this time is controlled according to the function 81 shown in FIG. Further, when the load state is a small load state, the CPU 17 executes the function D2.
is read from the storage device 18, and the duty of the excitation signal SGI with respect to the amount of depression of the inching pedal 15 is set as the fifth
It is determined according to the function D2 shown in the figure. SoshiU, CPU1
7 outputs the determined duty excitation signal SGI to the solenoid 5a in the same manner as described above to control the duty of the second electromagnetic solenoid valve 5. Therefore, the braking force corresponding to the amount of depression of the inching pedal 15 at this time is controlled according to the function 82 shown in FIG.
Play kino j becomes larger for the amount of depression of 5. As a result, when starting on a slope, if you press the inching pedal 15 in the same way as when the load is zero, the braking force will be greater than when the load is zero, so you may not be able to start and slide down. Further, there is no starting time lag, and the vehicle can be started with the same operating feeling as in a zero-load state. Similarly, when the load is large, the braking force relative to the amount of depression of the inching pedal 15 is greater than when the load is small. As a result, even if the load becomes even larger, the vehicle can start with the same operational feeling as when the load is zero, without being unable to start and sliding down, or with a start time lag, as described above. In this way, in this embodiment, when the inching pedal is operated to start the forklift, the braking force corresponding to the amount of depression of the inching pedal is varied in response to the difference in the load state applied to the drive system of the forklift. Inching operations can always be performed with a constant operating feeling regardless of the load condition. Note that the present invention is not limited to the above embodiments,
For example, by adding the weight of the cargo to the load condition, by making the inclination angle of the slope finer and adding it to the load condition, the load condition can be further increased and finer control can be performed; It is also possible to carry out the test using only the inclination angle as the load condition. Further, in the embodiment described above, the decoupling of the excitation signal SGI with respect to the amount of depression of the inching pedal 15 was calculated based on the functions D1 to D3 stored in the storage device 18, but this is calculated based on the amount of depression of the inching pedal 15 for each load state, for example. The duty data of the excitation signal SGI for each period may be stored in advance in the storage device 18, and the second electromagnetic solenoid valve 5 may be duty-controlled based on this data. In general, the hydraulic brake has been described in the above embodiment, but other brake mechanisms may be used as long as the braking force can be controlled according to the state of the load applied to the drive system during the inching operation. Effects of the Invention As described above, according to the present invention, when performing an inching operation,
Since the braking force is controlled according to the load applied to the drive system, an excellent effect is obtained in that the inching operation can always be performed with a constant operational feeling regardless of the load state applied to the drive system.

[Brief explanation of drawings]

Fig. 1 is a mechanism and electrical block circuit diagram of a forklift embodying this invention, Fig. 2 is a waveform diagram of an excitation signal, Fig. 3 is a diagram showing the relationship between brake force and hydraulic pressure of the wheel cylinder, and Fig. 4 is a diagram showing the relationship between brake force and hydraulic pressure of the wheel cylinder. Figure 5 is a diagram showing the relationship between the excitation signal duty and the hydraulic pressure of the wheel cylinder, Figure 5 is a diagram showing the relationship between the excitation signal decoute and the inching pedal depression amount, and Figure 6 is the relationship between the brake force and the inching pedal depression amount. FIG. 7 is a flowchart for explaining the effect on the forklift, and FIG. 8 is a diagram showing the relationship between the brake force and the amount of depression of the conventional inching pedal. Brake pedal 1, mask cylinder 2, first electromagnetic solenoid valve 3, solenoid 3a, boil cylinder,
Second electromagnetic solenoid valve 5, solenoid 5a, power unit 6, slope detection sensor 11, load detection sensor 1
2, Inching sensor 14, Inching pedal 15, C
PU17, storage device 18, lensoid drive circuit 19.2
0, Excitation signal SG1゜Patent applicant Toyota Industries Corporation Fujitsu
Co., Ltd. Agent Patent Attorney On 1) Hironobu ←, trl + 3 mar ← to Δ-7R -11 Δ-7R ← to 1 '''' also 3 peeps to all ← Moya year 32.\\ Tsukita Jo-゛ to Δ-7R Gin-ichi to Yasa I+V old two dogs

Claims (1)

[Scope of Claims] A brake for braking a cargo handling vehicle, a brake drive means for operating the brake and controlling the braking state of the brake, a load detection means for detecting a load state of the cargo handling vehicle, and an operation amount of an inching pedal. inching operation amount detection means for detecting the inching operation amount; determining means for determining the braking value of the brake with respect to the operation amount of the inching pedal according to the load condition of the cargo handling vehicle; An inching control device comprising: a control means for controlling the brake to a predetermined braking force by operating a brake drive means;