JPH0465262B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) The present invention relates to an inching control device for an industrial vehicle such as a forklift with an automatic transmission, and more specifically, to a device for controlling the engagement of a gear shift clutch during an inching operation. This invention relates to an inching control device.

(Prior Art) In a forklift equipped with an automatic transmission, the shifting clutch is controlled based on the traveling speed of the forklift and the amount of accelerator opening. Generally, when the gear shifting clutch changes from 1st gear (low speed) to 2nd gear (medium speed) or from 2nd gear (medium speed) to 3rd gear (high speed) (shift up), the gear shifting clutch is shown by the solid line in Figure 3. A shift boundary line L1 on the stairs that determines the shift region,
Switching is controlled according to L2.

On the other hand, when the gear shifting clutch changes from 3rd gear to 2nd gear or from 2nd gear to 1st gear (downshift), the gear shifting clutch moves along the shifting boundary line, also on the staircase, which determines the shifting area shown by the two-dot chain line in Figure 3. Switching is controlled according to L3 and L4.

When inching a forklift, agile movements such as starting, stopping, and running at very low speeds are required. It is being done. Similarly, in the case of a forklift with an automatic transmission, it is necessary to perform an inching operation after downshifting to the first speed state and bringing the vehicle into a low speed running state.

(Problem to be Solved by the Invention) However, in the case of a forklift with an automatic transmission, during the inching operation, the shift clutch is controlled to switch according to the shift boundary lines L3 and L4 shown by the two-dot chain line in FIG. After that, first step on the brake to reduce the driving speed and automatically switch the gearshift clutch to 1st gear (at this time, the accelerator opening amount is generally decreasing), and then start the inching operation, resulting in agile inching. There was a problem with the operation.

Also, during the inching operation, the vehicle is in 1st gear, but for example, because the traveling speed and the accelerator opening change particularly during the inching operation, the vehicle may change from 1st gear to 2nd gear or return from 2nd gear to 1st gear. Hunting occurred and there was a problem with the operability of the inching operation.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a plurality of speed change clutches, and a speed change clutch switching drive means for switching and connecting each of the speed change clutches. , an inching detector that detects the operation of the inching operation device for inching operation, and a first memory that stores shift data for normal running, which sets the shifting state to a gear shifting state suitable for normal running. a second storage device that stores shift data for an inching operation that sets a shift state to a shift state suitable for the inching operation during an inching operation; a discriminating means for discriminating whether normal running or inching work is being carried out based on the detection signal; and when the discriminating means determines that normal running is being carried out, reading speed change data for normal running stored in the first storage device; a first control means for actuating the shift clutch switching drive means to connect the corresponding shift clutch based on the inching operation; An automatic transmission characterized by comprising: second control means for reading speed change data for operation and operating the speed change clutch switching drive means based on the data to connect the corresponding speed change clutch. The gist of this paper is an inching control device for industrial vehicles.

(Function) Shift data for normal driving, which sets the shift state to a shift state suitable for normal driving, and shift data for inching operation, which sets the shift state to a shift state suitable for inching operation, are stored in the storage device. ,
When the determining means determines that normal driving is occurring based on the detection signal from the inching detector, the first control means reads out the speed change data for normal driving stored in the storage device and switches the speed changing clutch based on the same data. The driving means is actuated to connect the corresponding shift clutch, and when the discriminating means determines that it is an inching operation, the second control means reads out the shifting data for the inching operation stored in the storage device and controls the same. Based on this, the shift clutch switching drive means is actuated to connect the corresponding shift clutch.

As a result, in the case of normal driving, a speed change state suitable for normal driving can be obtained immediately, and in the case of inching operation, a speed change state suitable for inching operation can be immediately obtained, thereby improving the maneuverability of the forklift. This makes it possible to perform quick inching operations.

(Example) Next, a preferred example in which the present invention is embodied in a forklift will be described below with reference to the drawings.

FIG. 1 shows a hydraulic and electrical block circuit diagram of a forklift, in which a clutch oil pump 1 is driven by an engine (not shown), and pressure fluid from the pump 1 is supplied to a regulator valve 2. . This pressure fluid is then regulated to a constant pressure by a regulator valve 2 and supplied to a forward/reverse clutch switching valve 4 via a pressure control valve 3. The forward/reverse clutch switching valve 4 is turned on or off based on the operation of a clutch switching lever 5 provided at the driver's seat of the forklift vehicle, and supplies pressurized fluid to the forward/reverse clutch 6 to connect the forklift to drive the forklift forward or backward. Let's do it.

The pressure control valve 3 adjusts the pressure of the pressure fluid supplied to the forward/reverse clutch 6 and controls the clutch 6.
The pressure of the pressurized fluid supplied to the forward/reverse clutch 6 is adjusted by opening/closing an electromagnetic solenoid valve provided in the pressure control valve 3. This electromagnetic solenoid valve is driven and controlled by an electromagnetic solenoid 7 of the same valve.

Therefore, by controlling the excitation of the electromagnetic solenoid 7, the connection state of the forward/reverse clutch 6 is controlled.

When the solenoid 8a is de-energized, the 3-speed switching solenoid valve 8, which serves as a clutch switching drive means, transfers the pressure fluid from the regulator valve 2 to the 1st and 2-speed switching solenoid valve, which also serves as a clutch switching drive means, at the next stage. 9, and conversely, when energized, the pressure fluid is sent to a third speed clutch (hereinafter referred to as a third speed clutch) 10c, thereby establishing a connection for third speed (high speed) of the forklift.

The 1st/2nd speed switching solenoid valve 9 is a valve for switching the speed of the forklift between 1st speed (low speed) and 2nd speed (medium speed), and the solenoid 9
When a is de-energized, the pressure fluid is sent to a first speed clutch (hereinafter referred to as a first speed clutch) 10a,
When the connection for 1st speed of a forklift is energized, pressurized fluid is connected to the clutch for 2nd speed (hereinafter referred to as 2nd speed).
10b (referred to as a speed clutch) to establish a connection for second gear of the forklift.

Next, each of the solenoids 7, 8a, 9a is driven and controlled to control each of the clutches 6, 10a, 10b, 1.
An electric circuit for adjusting the pressure of pressure fluid supplied to 0c will be explained.

Inching sensor 1 as an inching detector
A potentiometer 1 detects depression of an inching pedal 12 as an inching operation device. Note that the inching pedal 12 is only mechanically connected to the inching sensor 11 and is not connected to other mechanical members.

The accelerator opening sensor 13 is composed of a potentiometer and detects the amount of depression of the accelerator pedal 14. In this embodiment, the accelerator pedal 14 is not mechanically connected to an engine throttle that operates an engine throttle valve, and the accelerator pedal 14 is only mechanically connected to the opening sensor 13.

The vehicle speed sensor 15 detects the rotational speed of the drive shaft of the forklift and outputs a detection signal thereof.

A central processing unit (hereinafter referred to as CPU) 16 as a first and second control means and a determination means is controlled by a read-only memory (hereinafter referred to as ROM) 17 as a first and second storage device. Operates according to the program and interface 1
8, each detection signal from the inching sensor 11, accelerator opening sensor 13, and vehicle speed sensor 15 is input.

Then, the CPU 16 uses this inching sensor 1.
Based on the detection signal No. 1, it is determined whether or not the inching pedal 12 is depressed. Further, the CPU 16 determines the amount of depression of the accelerator pedal 14 based on the detection signal from the accelerator opening sensor 13 and calculates the accelerator opening amount at that time, and also determines the traveling speed of the forklift based on the detection signal from the vehicle speed sensor 15. Calculate. Then, the CPU 16 controls the opening degree of the engine throttle and the number of revolutions of the engine based on the calculated accelerator opening amount. Note that the throttle opening degree relative to the amount of depression of the accelerator pedal 14 is set in advance, and the data is stored in the ROM 17.

Further, the CPU 16 outputs a predetermined drive signal to a solenoid drive circuit (not shown) via the interface 18, and controls the excitation of the electromagnetic solenoid 7 of the electromagnetic solenoid valve via the drive circuit.

In addition to the control program, the ROM 17 stores shift data for normal driving (driving state other than inching operation) and inching operation (accelerator pedal 14).
Shift data is stored for a state in which the fork is driven at an increased vertical speed by blowing the fork. Shift data for normal driving is accelerator pedal 14
Shift data for switching the 1st to 3rd gear clutches 10a to 10c to the optimum gear shifting state based on the amount of depression of the accelerator, that is, the amount of opening of the accelerator and the traveling speed of the forklift. -3rd speed clutches 10a to 10c are controlled to switch. In this embodiment, the data of each shift region is stored in relation to the accelerator opening amount and the traveling speed as shown in FIG. In addition, the shift boundary lines L1 to L4 are set to be different for upshifting and downshifting.

The speed change data for the inching operation is the speed change data for switching the speed change state to the first speed clutch 10a suitable for the inching operation based on the traveling speed of the forklift.
The first to third speed clutches 10a to 10c are controlled to switch. In the present embodiment, the data is stored as data of each shift region with respect to the accelerator opening amount and the traveling speed, and as shown by the broken line in FIG. 3 and the solid line in FIG. The shift boundary line L5 that separates the
The speed change range has been expanded to include the maximum travel speed position.

Therefore, in the case of an inching operation, the 1st speed region occupies a very wide speed range, and the shifting state does not change due to fluctuations in the accelerator opening amount, so the shifting state suitable for the inching operation is immediately achieved. It also makes it possible to maintain the first gear shift state even if the accelerator is pressed to increase the speed of the fork's ascent and descent.

Further, the CPU 16 determines whether normal running or inching operation is performed based on the detection signal from the inching sensor 11. When the CPU 16 determines that the vehicle is running normally, the CPU 16 selects the shift data for the normal drive, and selects the shift data for the normal drive based on the accelerator opening amount and the running speed.
A drive signal read from the ROM 17 is output to the solenoid drive circuit 19 to drive and control the solenoids 8a and 9a of the 3rd speed and 2nd speed switching electromagnetic valves 8 and 9. On the other hand, when it is determined that an inching operation is to be performed, the CPU 16 selects the speed change data for the inching operation, and stores the speed change data for the predetermined inching operation in the ROM 17 based on the traveling speed.
The readout drive signal is output to the solenoid drive circuit 19 to drive and control the solenoids 8a and 9a.

Readable and rewritable memory (hereinafter referred to as
RAM) 20 is designed to temporarily store various calculation results of the CPU 16.

Next, the operation of the forklift constructed as described above will be explained.

Now, when the forklift is running normally forward, the CPU 16 determines that the forklift is running normally based on the detection signal from the inching sensor 11, and moves on to read out the speed change data for normal running. The CPU 16 calculates the current accelerator opening amount based on the detection signal from the accelerator opening sensor 13, calculates the current traveling speed based on the detection signal from the vehicle speed sensor 15, and sets a predetermined value based on both calculated values. Shift data for normal driving is read from the ROM 17. Next, the CPU 16 drives and controls the solenoids 8a and 9a of the 3rd speed and 1st/2nd speed switching electromagnetic valves 8 and 9 via the solenoid drive circuit 19 based on the read speed change data,
The 1st to 3rd speed clutches 10a to 10c are brought into a predetermined connected state to change gears based on the read shift data.

Therefore, during normal driving, the forklift
Shift data for normal driving is read from the ROM 17, and the shift state is controlled based on the read shift data.

Next, when the inching pedal 12 is depressed to perform an inching operation, the CPU 16 determines that it is an inching operation based on the detection signal from the inching sensor 11, and proceeds to read out the speed change data for the inching operation. The CPU 16 calculates the current traveling speed based on the detection signal from the vehicle speed sensor 15, and reads out speed change data for a predetermined inching operation from the ROM 17 based on the determined traveling speed. Next, the CPU 16 drives and controls the solenoids 8a and 9a of the 3rd speed and 1st and 2nd speed switching electromagnetic valves 8 and 9 via the solenoid drive circuit 19 based on the read speed change data, and controls the 1st to 3rd speed clutches 10a to 3. 10c is brought into a predetermined connection state and set to a speed change state based on the read speed change data.

At this time, since the first speed region of the shift data for the inching operation occupies a very wide speed range, the shift state immediately shifts to the first speed, which is suitable for the inching operation. Furthermore, since this is set at the highest speed in 1st gear, the engine will not overrun even when downshifting.

In addition, the shift data for the inching operation is designed so that the shift state will not change due to changes in the amount of accelerator opening, so even if the accelerator is pressed to increase the fork's vertical speed, the shift state of 1st gear will not change. Never.

As described above, in this embodiment, different gear shift data suitable for the drive are selected and read out for normal running and for inching operation, and each clutch 9a to 9c is controlled to switch based on the shift data. Ru. Therefore, in the case of normal driving, a gear change state suitable for normal driving can be obtained immediately, and in the case of inching operation, a gear change state suitable for inching operation can be immediately obtained, improving the operability of the forklift and making it more agile. Inching operations can be performed.

Effects of the Invention As detailed above, according to the present invention, different gear shift data suitable for the driving are separately prepared for normal driving and for inching operation, and the same is prepared for normal driving and inching operation. The selected and read out gear shift data were selected and each clutch was switched and controlled based on the gear shift data. Therefore, in the case of normal driving, the gear shifting state suitable for normal driving is achieved, and in the case of inching operation, the shifting state is suitable for inching operation. The speed change state can be obtained immediately, which has the excellent effect of improving the operability of the forklift and allowing quick inching operations.

[Brief explanation of drawings]

Fig. 1 is a hydraulic and electrical block circuit diagram of a forklift embodying this invention, Fig. 2 is a diagram showing the contents of the readable and rewritable memory (ROM), and Fig. 3 is a diagram showing the accelerator opening during normal driving. Figure 4 shows the speed change range based on the accelerator opening amount and travel speed during inching operation. Figure 5 explains the processing operation of the central processing unit (CPU). This is a flowchart for In the figure, 1 is a clutch oil pump, 2 is a regulator valve, 3 is a pressure control valve, 4 is a forward/reverse clutch switching valve, 5 is a clutch switching lever, 6 is a forward/reverse clutch, 8 is a 3-speed switching solenoid valve, 9 is a 1st/2nd speed switching electromagnetic valve, 10a is a 1st speed clutch, 10b is a 2nd speed clutch, 10c is a 3rd speed clutch, 11 is an inching sensor, 12 is an inching pedal, 13 is an accelerator opening sensor, 15 is a vehicle speed sensor, 16 is a central processing unit (CPU), 17 is a read-only memory (ROM), and 19 is a solenoid drive circuit.

Claims (1)

[Scope of Claims] 1. A plurality of shift clutches, a shift clutch switching drive means for switching and connecting each of the shift clutches, and an inching detector for detecting operation of an inching operation device for inching operation. , a first storage device that stores shift data for normal running, which sets the gear shift state to a gear shift state suitable for normal running during normal running; and a first storage device that stores shift data for normal running; a second storage device storing speed change data for an inching operation to be set; and a determining means for inputting a detection signal from the inching detector and determining whether normal running or inching operation is being performed based on the detection signal. When the determining means determines that the vehicle is running normally, it reads out the shift data for normal running stored in the first storage device and operates the shift clutch switching drive means based on the same data to perform the corresponding shift shift. a first control means for connecting the clutch; and when the determining means determines that an inching operation is being performed, reads out the speed change data for the inching operation stored in the second storage device and switches the speed change clutch based on the same data; 1. An inching control device for an industrial vehicle equipped with an automatic transmission, comprising: second control means for activating a drive means and connecting a corresponding transmission clutch.