JP2000179372A - Vehicle speed control device for forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have limiting speed observed without lowering cargo carrying performance by providing a fork lift with speed-limited outdoor and indoor running modes as a running mode other than a cargo operation mode. SOLUTION: According to switching of an ultrasonic sensor 4 which detects whether a vehicle is located indoors or outdoors and cargo lever switches 34, 35, solenoid valves 2, 3, and negative pressure actuators 18, 19 are actuated selectively to set spring tension of a governor spring 13 to one of the three levels. The spring tension is set to the highest level during cargo operation, and to a low level during indoor running, and to the middle during outdoor running. In any case, the maximum engine speed according to the strength of the governor spring 13 is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device for a forklift, which limits the vehicle speed by lowering the engine speed than during cargo handling from the viewpoint of preventing accidents when the forklift is running. The present invention relates to a vehicle speed control device capable of selectively switching a driving mode having a different speed limit according to a difference in conditions such as an outdoor driving and an indoor driving even when the vehicle is running.

[0002]

2. Description of the Related Art For example, in a gasoline engine type forklift, a pneumatic governor device provided in an engine intake system (throttle system) is used for loading and unloading during vehicle running, particularly for the purpose of preventing an accident due to excessive speed during indoor running. The vehicle speed is restricted by suppressing the engine speed more than at the time of work (for the pneumatic governor itself, see Japanese Patent Application Laid-Open No. 5-99001 and Japanese Utility Model Application Laid-Open No. 6-87642).

[0003]

In the prior art as described above, the suction negative pressure on the intake manifold side is selectively introduced into the negative pressure chamber of the pneumatic governor device, and the opening of the governor valve is increased during cargo handling. In general, when the vehicle is running, the governor valve is switched to a small opening to adjust the engine speed, thereby limiting the vehicle speed while driving without reducing the cargo handling performance. The maximum vehicle speed determined by the pneumatic governor device remains constant regardless of whether the vehicle is running or indoors.

Since the vehicle speed determined by the pneumatic governor is set on the assumption that the vehicle is traveling indoors as described above, the vehicle travels at low speed even when traveling outdoors even when traveling indoors. In addition, the work efficiency is lowered and the operator is irritated.

[0005] In some logistics sites, different speed limits are set for indoor and outdoor travel, and the operator is obliged to comply with the speed limit in any case. However, in the above-described conventional system, the observance of the speed limit depends only on the will of the operator, so that the intended purpose cannot always be sufficiently achieved.

[0006] The present invention has been made in view of the above problems, without affecting the cargo handling performance,
Ability to selectively switch the driving mode from among a plurality of vehicle speed limited driving modes when driving the vehicle, improving work efficiency and eliminating the irritability of the operator, and restricting both indoor driving and outdoor driving in particular. It is an object of the present invention to provide a structure capable of complying with speed.

[0007]

According to a first aspect of the present invention, a plurality of vehicle speed limited travel modes based on a throttle system engine maximum speed control function are set separately from a cargo handling mode. It is characterized in that it can be selectively switched to any one of the plurality of vehicle speed limited traveling modes.

The selection switching of the plurality of vehicle speed limited traveling modes may be, for example, a high-speed, low-speed two-speed switching, or a high-speed, middle-speed, low-speed three-speed switching. Also,
The speed limit, that is, the maximum speed in each of the above-described vehicle speed limited traveling modes can be set to an arbitrary value in advance, and as a result, even in any vehicle speed limited traveling mode, even if the accelerator pedal is depressed to the maximum pedal angle. Even so, it is adjusted in advance so as not to exceed the respective speed limits.

According to a second aspect of the present invention, the selection of the travel mode is switched by a selection operation of a plurality of negative pressure actuators attached to a throttle system.

Further, the invention according to a third aspect of the present invention further includes, in addition to the configuration of the second aspect, a cargo handling sensor for detecting that a cargo handling operation has been performed, and when the cargo handling sensor is activated, the traveling mode is released. Then, the operation mode is switched to the cargo handling mode, and the cargo handling mode is a power mode having a higher output than each vehicle speed limited traveling mode which is a traveling mode.

[0011] The invention described in claim 4 is the same as the claim 3.
In the invention described in (1), the selection of the travel mode is switched by switching the travel mode switching means.

According to a fifth aspect of the present invention, the driving mode switching means according to the fourth aspect of the present invention comprises a sensor for detecting whether the vehicle itself is indoors or outdoors. The indoor travel mode is characterized in that the outdoor travel mode having a higher speed limit than the indoor travel mode when the outdoor is detected is selected.

As the sensor as the traveling mode switching means, for example, an optical sensor or an ultrasonic sensor is used, and the vehicle is indoors depending on the presence or absence of a roof or ceiling above the vehicle, or a pillar or luggage on the side of the vehicle. Or outdoors.

Therefore, in the first and second aspects of the present invention, since a plurality of vehicle speed limited traveling modes are provided as traveling modes, the traveling mode is selectively switched by the operator or automatically. By doing
It is possible to travel at a high speed in an area where high-speed traveling is possible and at a low speed in an area where low-speed traveling is obligatory. In this case, since the cargo handling mode is completely independent of the traveling mode, the cargo handling performance is not affected regardless of which vehicle speed limited traveling mode is selected.

[0015] In the third and fourth aspects of the present invention,
Since the loading operation mode is a power mode having a higher output than a plurality of vehicle speed limited traveling modes, which are traveling modes, a necessary and sufficient cargo handling performance is secured.

According to the fifth aspect of the present invention, when the sensor as the driving mode switching means detects that the vehicle itself is indoors, the indoor driving mode is selected, and when the sensor detects that the vehicle itself is outdoors, the indoor driving mode is selected. The outdoor traveling mode having a higher speed limit than the mode is selected. Then, in any of the traveling modes, traveling within the range of each speed limit is possible.

[0017]

According to the first aspect of the present invention, a plurality of vehicle speed limited traveling modes are provided as traveling modes, and these modes are set in accordance with conditions such as indoor traveling and outdoor traveling. Since it is possible to select and switch to any of the above, in any of the traveling modes, not only does not affect the cargo handling performance at all, for example, when traveling indoors and when traveling outdoors Even when traveling at different speed limits is obligatory, it is possible to achieve both safety and improvement of work efficiency while observing the respective vehicle speed limits, and to eliminate the irritability of the operator. effective.

According to the second aspect of the present invention, the selection of the driving mode is switched by a plurality of negative pressure actuators attached to the throttle system, so that the same effect as the first aspect of the present invention is obtained. In addition to the above, there is an effect that the intended purpose can be achieved by making a slight improvement to the existing device.

According to the third and fourth aspects of the present invention, when the cargo handling sensor detects that the cargo handling mode is the cargo handling mode, the traveling mode is released and the cargo handling mode is the traveling mode. The power mode has a higher output than the vehicle speed limited driving mode, so it not only has no effect on the cargo handling performance but also secures the necessary and sufficient cargo handling performance while balancing the cargo handling performance and the running performance There is an effect that can be done.

According to the fifth aspect of the present invention, the indoor driving mode is set when the vehicle is indoors by the sensor as the driving mode switching means, and the vehicle is set outdoors by the sensor. When detected, the outdoor traveling mode higher in speed than the indoor traveling mode is automatically selected. Therefore, in addition to the same effect as the invention according to claim 4, the vehicle speed limited traveling mode which is the traveling mode There is no selection error, and the operation reliability and safety are further improved.

[0021]

1 to 7 show a preferred embodiment of the present invention. In particular, FIG. 1 shows a first embodiment of a specific configuration of a vehicle speed control device itself in a gasoline engine type forklift. Is shown.

As shown in FIG. 1, the vehicle speed control device is roughly divided into a pneumatic governor device 1, solenoid valves 2 and 3, and an ultrasonic sensor 4 for indoor / outdoor detection functioning as running mode switching means. In addition, it includes a power supply circuit 5 and the like.

As is well known, the pneumatic governor device 1 is provided, for example, downstream of a throttle valve in an intake system of a gasoline engine, more specifically, a throttle system (not shown).
The governor valve 6 is formed integrally with the shaft 7, and opens and closes the intake passage 8 through the shaft 7 to the case 9 of the pneumatic governor device 1 itself forming a part of the intake passage 8. So that it is rotatable. Further, the shaft 7 protrudes into a spring accommodating portion 10 formed integrally with the case 9, and a governor cam 11 is integrally formed at a protruding end of the shaft 7. A leaf spring 12 is attached to the governor cam 11. A governor spring (tensile coil spring) 13 serving as an urging means disposed in the spring accommodating portion 10 is connected via the spring accommodating portion 10.

The other end of the governor spring 13 is connected to an adjusting rod 15 screwed to an adjusting sleeve 14.
5 is a swing lever 1 pivotally supported on a case 10 by a pin 16.
7.

Further, two diaphragm-type negative pressure actuators 18 and 19 are arranged adjacent to the case 10 of the pneumatic governor device 1. Each of these negative pressure actuators 18 and 19 has the same structure, and includes a diaphragm 21 separating the inside of the chamber 20 into two chambers, and a diaphragm rod 22 connected to the diaphragm 21 and protruding from the chamber 20. And the diaphragm 2 provided in the negative pressure chamber 23 which is one of the chambers.
1 and a return spring 24 for urging the diaphragm rod 22 and the like.
Are bent at substantially right angles, and face the side of the swing lever 17 so as to be able to come into contact with the side of the swing lever 17 respectively.

The negative pressure actuators 18, 19
In the negative pressure chamber 23, suction negative pressure on the intake manifold side or negative pressure from a vacuum pump (not shown) is selectively introduced in accordance with the switching operation of the solenoid valve 2 or 3 as described later. Has become. As a result, the spring force of the governor spring 13 is switched between three levels, by swinging the swing lever 17 in accordance with the selection operation of the negative pressure actuators 18 and 19 and sliding the adjustment rod 15, as will be described later. It has become.

More specifically, when two negative pressure actuators 18 and 19 introduce negative pressure, the diaphragm rod 2
Assuming that the two strokes are equal to each other, the swing angle of the swing lever 17 when the one negative pressure actuator 18 is operated is longer than that when the other negative pressure actuator 19 is operated, and thus the adjustment rod by the swing lever 17 is adjusted. Fifteen
The contact distance, effective stroke, and the like of each diaphragm rod 22 with respect to the swing lever 17 are set in advance so that the sliding amount becomes large.

A lock nut 25 is attached to the spring accommodating section 10 together with the adjusting sleeve 14, and an adjusting nut 26 is provided at the other end of the diaphragm rod 22 in each of the negative pressure actuators 18 and 19. By these operations, the spring force of the governor spring 13 can be finely adjusted, while the effective stroke of each diaphragm rod 22 can also be finely adjusted.

Therefore, as shown in FIG. 1, in a state where no negative pressure is introduced into the negative pressure chambers 23 of both the negative pressure actuators 18 and 19 (an indoor traveling mode state described later),
The governor spring 13 has a weak spring force, and urges the governor valve 6 in the opening direction with the weak spring force. Then, the governor valve 6 opens and closes by controlling the pressure difference between the upstream and downstream of the governor valve 6, that is, the negative pressure generated downstream of the governor valve 6 in accordance with the operation state, thereby controlling the mixture supply amount. Control.
More specifically, when the accelerator pedal is depressed to the maximum angle, the negative pressure on the downstream side of the governor valve 6 increases, so that the governor valve 6 becomes almost fully closed. The speed limit in the indoor travel mode, which is the limited travel mode, is set to, for example, 5 to 6 km / h to limit an increase in the engine speed more than that.

On the other hand, when a negative pressure is introduced from the solenoid valve 2 into the negative pressure chamber 23 of one of the negative pressure actuators 19, that is, in an outdoor running mode described later, the adjusting rod is 15 is pulled leftward in FIG. 1 to increase the spring force of the governor spring 13. As a result, although the governor valve 6 opens and closes in response to the negative pressure generated on the downstream side in the same manner as described above, the governor spring 6 that biases the governor valve 6 itself in the opening direction has a large spring force. The maximum number of revolutions of the engine determined by the opening degree of the governor valve 6 is higher than that in the indoor driving mode, and as a result, a higher output is obtained than in the indoor driving mode, so that driving at higher speed is possible. That is, in the outdoor traveling mode, which is the vehicle speed limited traveling mode on the high speed side, when the accelerator pedal is depressed to the maximum angle, the governor valve 6 is close to the fully closed state due to the negative pressure action on the downstream side of the governor valve 6. Even if this happens, for example, the speed limit in the outdoor running mode is set to, for example, 10 to 12 km / h to limit the engine speed from rising further.

The same applies to the case where a negative pressure is introduced from the solenoid valve 2 into the negative pressure chamber 23 of the other negative pressure actuator 18, that is, in the loading operation mode described later. The adjustment rod 15 is pulled most to the left in FIG.
The spring force of the governor spring 13 is maximized. As a result, the governor valve 6 opens and closes in response to the negative pressure generated on the downstream side in the same manner as described above, but the spring force of the governor spring 13 that biases the governor valve 6 in the opening direction is larger than in the traveling mode. Finally, the maximum number of revolutions of the engine finally determined by the opening degree of the governor valve 6 becomes larger than that in the outdoor running mode, and
As a result, necessary and sufficient cargo handling performance can be exhibited.

The solenoid valves 2 and 3 provided in front of the negative pressure actuators 18 and 19 have output ports 27 connected to the negative pressure chambers 23 of the negative pressure actuators 18 and 19, respectively. The input port 28 is connected to an air cleaner (not shown), and the other input port 29 is also connected to an intake manifold (not shown) or a vacuum pump (not shown). In a normal state where the solenoid 30 is not energized, the spool 31 is at the left offset position shown in FIG. 1, the atmospheric pressure on the air cleaner side is introduced into the negative pressure chamber 23, and the spool 31 is moved to the right. When the position is switched to the offset position, the suction negative pressure on the intake manifold side or the negative pressure from the vacuum pump is introduced into the negative pressure chamber 23 of the negative pressure actuator 18 or 19.

The power supply circuit 5 connecting the solenoids 30 of the solenoid valves 2 and 3 and the battery 32 includes an ignition key switch 33, a plurality of cargo handling lever switches 34 and 35 as cargo handling sensors, and relays 36 and 3.
7, 38 and the ultrasonic sensor 4 are interposed. The above-mentioned cargo handling lever switches 34 and 35 are provided independently for each cargo handling operation lever such as a lift operation lever and a tilt operation lever. The two solenoid valves 2 and 3 are selectively turned on and off in accordance with the ON-OFF operation of the cargo handling lever switches 34 and 35 and the ultrasonic sensor 4 and the switching operation of each of the relays 36 to 38. Has become.

As shown in FIGS. 2 and 3, the ultrasonic sensor 4 has a pillar of a head guard for detecting whether the vehicle 39 is outdoors or indoors so as to function as running mode switching means. For example, as shown in FIG. 2, when it is determined whether the work area is outdoors or indoors based on the presence or absence of a ceiling 41, a beam or a roof 42 of a building in the work area, as shown in FIG. As shown in FIG. 3, it is mounted sideways when discriminating whether it is outdoors or indoors based on the presence or absence of pillars 43 and luggage 44 on the floor as shown in FIG. In the example of FIG. 1, when the ultrasonic sensor 4 detects an obstacle such as the ceiling 41 or the pillar 43 and the ultrasonic sensor 4 is turned on, power is supplied to the coil of the relay 37. I have.

According to the present embodiment configured as described above, as shown in FIG.
In the OFF state of No. 3, the contacts of the relays 36 to 38 are respectively on the a side, and the ignition key switch 33 is turned off.
When N is set, the solenoid 30 of the solenoid valve 3 is energized to immediately enter the outdoor running mode. On the other hand, when one of the loading operation levers is operated during the loading operation, the loading lever switch 34 or 35 is activated. Immediately, the relay 36 reverses, and the solenoid 3 of another solenoid valve 2 is switched to the cargo handling mode.
It has a so-called cargo handling operation priority circuit configuration so as to be energized to zero.

That is, as shown in Table 1 in addition to FIG.
When the vehicle is running in a mode other than the cargo handling mode, the vehicle 3 is controlled on the condition that the ignition key switch 33 is in the ON state.
Whether the sensor 9 itself is outdoors or indoors is detected by the ultrasonic sensor 4, and the relays 37 and 38 are switched in response to the detection, so that the vehicle can travel at a higher speed when traveling outdoors than when traveling indoors.

[0037]

[Table 1]

More specifically, unless the ultrasonic sensor 4 detects, for example, the ceiling 41 or the pillar 43 shown in FIG. 2, the ultrasonic sensor 4 is in the OFF state, and this OFF state means that the vehicle 39 is outdoors. Means During traveling outdoors, as described above, the contacts of the relays 36 to 38 are located on the terminal a, respectively. Therefore, when the solenoid 30 of one of the solenoid valves 3 is energized via the relays 36 and 37, the solenoid valve is turned on. 3 is switched to the right offset position. By the switching of the solenoid valve 3, a predetermined negative pressure is introduced into the negative pressure chamber 23 of the negative pressure actuator 19, and the spring of the governor spring 13 responds to the sliding displacement of the adjusting rod 15 accompanying the swing of the swing lever 17. The power is increased, and as a result, the maximum engine speed determined by the opening of the governor valve 6 is increased. As described above, the spring force of the governor spring 13 at this time is set to be smaller than that in the cargo handling mode and larger than that in the indoor traveling mode. In other words, the maximum speed limit on the high speed side (10 to 12 km / h) under the power which is smaller than that during the cargo handling operation and larger than the indoor travel time when traveling outdoors.
h) is realized.

On the other hand, the ultrasonic sensor 4 is
When the ultrasonic sensor 4 is turned on, the ultrasonic sensor 4 is turned on, and it is determined that the vehicle 39 is indoors. When the ultrasonic sensor 4 is turned ON, as described above, the ultrasonic sensor 4
The coil of the relay 37 is energized through itself. When the coil of the relay 37 is energized, the contact of the relay 37 is switched to the terminal b, and the energization of the solenoid valve 3 is blocked. As a result, no negative pressure is introduced into any of the negative pressure actuators 18 and 19, and the swing lever 17 and the adjustment rod 15 are maintained in the state shown in FIG. 1, and as a result, the spring force of the governor spring 13 is reduced to the outdoor running mode. And the maximum rotation speed of the engine determined by the opening of the governor valve 6 is also limited as compared with the time of outdoor traveling. 6km / h)
The indoor traveling mode as the low-speed traveling mode is realized.

When the vehicle is traveling indoors, the relay 3
Since the contact of the relay 37 is switched to the terminal b by energizing the coil of the relay 37 because the contact of the relay 6 is on the terminal a side, the coil 3 is also passed through the contact and the terminal.
Even if the ultrasonic sensor 4 is turned off after the ultrasonic sensor 4 is once turned on because the electric current is supplied to 7a, the connection state between the contact and the terminal b in the relay 37 is maintained by itself. That is, even if the user goes outdoors in the indoor traveling mode, the indoor traveling mode is continued. However, after the vehicle is left outdoors in the indoor traveling mode, if one of the cargo handling levers is momentarily operated and the corresponding cargo handling lever switch 34 or 35 is temporarily turned on, the coil of the relay 36 is connected to the coil. The energization cuts off the energization from the relay 36 to the relay 37 side, and instantaneously switches to the outdoor running mode, which is the high-speed running mode.

When the ignition key switch 33 is
In the N state, when one of the cargo handling levers is operated in the cargo handling operation, the corresponding cargo handling lever switch 34 or 35 is turned ON.
And the contact of the relay 36 is connected to the terminal b.
Switch to the side. As a result, when the solenoid 30 of the solenoid valve 2 is energized via the relay 38, the spool 31 of the solenoid valve 2 is switched to the right offset position. By the switching of the solenoid valve 2, a predetermined negative pressure is introduced into the negative pressure chamber 23 of the other negative pressure actuator 18, and the swing lever 17
The spring force of the governor spring 13 is increased in accordance with the sliding displacement of the adjusting rod 15 due to the swing of the engine, and as a result, the maximum engine speed determined by the opening of the governor valve 6 is increased. At this time, the spring force of the governor spring 13 is larger than those in the indoor traveling mode and the outdoor traveling mode, and is the largest among the three modes. It is possible to work at full power without being restricted by the rotation speed limiting function).

As described above, according to the present embodiment, the speed limit driving mode of the vehicle is a low speed speed limit driving mode in which the vehicle 39 is automatically switched according to whether the vehicle 39 is indoors or outdoors. Since it has an indoor traveling mode and an outdoor traveling mode, which is a speed-limiting traveling mode on the high-speed side, it is necessary to comply with the speed limit both indoors and outdoors when the cargo handling performance is not reduced. As a result, it is possible to effectively eliminate the frustration of the operator while achieving both improvement in safety and improvement in work efficiency.

FIG. 4 is a view showing a second embodiment of the present invention, and shows a configuration of a vehicle speed control device of a diesel engine type forklift. Note that parts common to those in FIG. 1 are denoted by the same reference numerals.

In this embodiment, two throttle levers 51 are provided coaxially with a throttle valve attached to an injection pump (not shown) and an accelerator wire 52 for connecting an accelerator pedal (not shown). By selectively switching the position of the other swing lever 54 with respect to the one swing lever 53 with the swing levers 53 and 54 interposed therebetween, according to the cargo handling mode, the indoor travel mode, and the outdoor travel mode. In addition, the opening of the throttle valve and, consequently, the engine speed are limited.

As shown in FIG. 4, two rocking levers 53, 54 are supported by a mounting bracket 55 via pins 56 so as to be overlapped with each other so as to be rockable. Negative pressure actuators 68 or 69 are mounted on 54 via brackets 57 or 58 in opposite directions. These negative pressure actuators 6
The structure of 8, 69 is the same as that shown in FIG. 1. The diaphragm rod 59 of one negative pressure actuator 69 on the swing lever 53 side extends to the other swing lever 54 side, and is substantially at a right angle. The bent tip is the swing lever 5
4 is in contact with the end face. Also, the diaphragm rod 60 of the other negative pressure actuator 68 on the swing lever 54 side
Extends toward the other swinging lever 53, and a tip portion thereof bent at a substantially right angle can abut on an end face of the swinging lever 53.

The negative pressure chambers of the negative pressure actuators 68 and 69 apply the pressure to be introduced into the negative pressure chambers to the negative pressure from the vacuum pump, similarly to the first embodiment shown in FIG. Alternatively, it is connected to a solenoid valve 2 or 3 for selectively switching to the atmospheric pressure on the air cleaner side. The vacuum pump referred to here is attached to the injection pump and is driven directly by the engine to generate a negative pressure according to the engine speed.

The swing lever 53 has a pedal-side accelerator wire 52 connected to an accelerator pedal (not shown).
a and the other swing lever 5
A lever-side accelerator wire 52b connected to a throttle lever 51 is connected to the throttle lever 4, and a counterclockwise return force by a return spring (not shown) is constantly applied to the throttle lever 51.

The position of the other swing lever 54 with respect to the one swing lever 53 is, as shown in FIG. 4, an indoor travel mode position DL which is a low speed side speed limited travel mode and a high speed side speed limited travel mode. It can be selectively switched to either the outdoor traveling mode position DH or the cargo handling mode position FP, and both the negative pressure actuators 68, 69
In the state where no negative pressure is introduced, the swing lever 54 is held at the indoor traveling mode position DL indicated by a solid line in FIG.

On the other hand, when a negative pressure is introduced into the negative pressure actuator 69 on the side of the swing lever 53, the swing lever 54 moves outdoors as shown in FIG. It swings to the mode position DH, and as a result, the opening of the throttle valve coaxially integrated with the throttle lever 51 is made larger than in the indoor running mode.

When a negative pressure is introduced into the negative pressure actuator 68 on the swing lever 54 side, the diaphragm rod 6
0, the swing lever 54 swings together with the negative pressure actuator 68 to the cargo handling work mode position FP as shown in FIG. 6, and as a result, the opening of the throttle valve is reduced in the outdoor running mode. It is being enlarged even more.

Therefore, regardless of the position of the other swing lever 54 with respect to the swing lever 53 in any of the three positions, the swing lever is released when the pedaling force of the accelerator pedal is released. When the accelerator pedal is depressed, one of the swing levers 53 pulled by the pedal-side accelerator wire 52a swings, and at the same time, the movement of the swing lever 53 is controlled. In conjunction therewith, the engagement between the diaphragm rod (tip) 59 of the negative pressure actuator 69 and the swing lever 54 or the engagement between the diaphragm rod (tip) 60 of the other negative pressure actuator 68 and the swing lever 53. Therefore, the other swing lever 54 also swings, and the throttle lever 51 rotates.

Here, when the swing lever 54 is in the indoor traveling mode position DL, the maximum speed of the vehicle is about 5 to 6 km / h even if the accelerator pedal (not shown) is depressed to the maximum pedal angle. The maximum opening of the throttle valve is regulated. Similarly, when the swing lever 54 is at the outdoor travel mode position DH, even if the accelerator pedal (not shown) is depressed to the maximum pedal angle, the throttle valve is set so that the maximum speed of the vehicle is about 10 to 12 km / h. Of the swing lever 54 is restricted.
Is in the outdoor driving mode position DH, the maximum opening of the throttle valve is regulated so that the maximum speed of the vehicle is about 10 to 12 km / h even if the accelerator pedal (not shown) is depressed to the maximum depression angle. .

On the other hand, the power supply circuit 5 includes the ultrasonic sensor 4 and the loading / unloading lever switches 34 and 3 similar to those of the first embodiment.
5 and relays 36, 37, and 38, a relay 61 parallel to the relay 36 and a speed switch 62 are interposed. The speed switch 62 is turned ON when the vehicle speed reaches a predetermined speed, and the relay 61 When the coil is energized, the contact of the relay 61 is opened. However, the set vehicle speed at which the speed switch 62 is turned ON is set smaller than the speed limit in the outdoor running mode (about 10 to 12 km / h in the present embodiment).

This is because a diesel engine type forklift has a low acceleration characteristic, so that the opening of the throttle valve is not restricted from the beginning to maintain the speed limit when traveling outdoors. This is to allow acceleration at full power until the acceleration reaches.

According to the second embodiment configured as described above, as shown in Table 2 in addition to FIG. 4, when the vehicle is running in a mode other than the cargo handling operation mode, the ignition key switch 33 is turned off.
Under the condition that the vehicle is in the N state, the ultrasonic sensor 4 detects whether the vehicle 39 itself is outdoors or indoors, and accordingly, the relays 37 and 38 function as traveling mode switching means, and the first As in the embodiment, it is possible to run at a higher speed when traveling outdoors than when traveling indoors.

[0056]

[Table 2]

More specifically, as long as the ultrasonic sensor 4 does not detect, for example, the ceiling 41 or the pillar 43 shown in FIGS.
The ultrasonic sensor 4 is in an OFF state, which means that the vehicle 39 is outdoors. When traveling outdoors, the relays 36 to 38 and 6
Since each of the contacts 1 is on the terminal a, the relay 36,
37, the solenoid 3 of one solenoid valve 3
When power is supplied to 0, the spool 31 of the solenoid valve 3 is switched to the right offset position. By the switching of the solenoid valve 3, the negative pressure from the vacuum pump is introduced into the negative pressure chamber of the negative pressure actuator 69, and the swing lever 54 is pulled by the diaphragm rod 59 of the negative pressure actuator 69, as shown in FIG. It swings counterclockwise to the outdoor travel mode position DH.

In the state where the swing lever 54 is in the outdoor running mode position DH, the maximum speed of the vehicle when the accelerator pedal is depressed to the maximum pedal angle is 10 to 12 km.
/ H, the maximum engine speed determined by the opening of the throttle valve is regulated.
Accordingly, the high-speed traveling mode at the above-described high-speed limit speed (about 10 to 12 km / h) is realized under the power smaller than that during the cargo handling operation and larger than the indoor traveling time when traveling outdoors.

Here, even in the outdoor running mode, if the vehicle speed has not reached the set speed to be detected by the speed switch 62 (that is, if the vehicle is not sufficiently accelerated), the speed switch 62 remains OFF, and at the same time as the solenoid valve 3 is energized through the relays 36 and 37, the other solenoid valve 2 is also energized through the relays 61 and 38. Is also operated, and the swing lever 54 is moved to the cargo handling mode position F as shown in FIG.
The throttle valve swings to P, and as a result, the throttle valve is kept at the same opening as in the cargo handling mode. Therefore, even in the outdoor running mode, if the acceleration of the vehicle is not sufficient, it is possible to accelerate with substantially the same full power as in the cargo handling mode.

Eventually, in the outdoor running mode described above,
If the vehicle speed reaches the set speed even if it does not reach the speed limit,
This is detected by the speed switch 62 in FIG.
Since the first contact is opened, the current supply to the solenoid valve 2 through the relay 61 and the relay 38 is cut off. As a result, the introduction of the negative pressure to the negative pressure actuator 68 is interrupted, and the swing lever 54 returns to the state shown in FIG. 5 and shifts to the outdoor running mode described above.

On the other hand, when the ultrasonic sensor 4 detects the ceiling 41, the pillar 43 and the like shown in FIGS. 2 and 3, the ultrasonic sensor 4 is turned on, and it is determined that the vehicle 39 is indoors.
When the ultrasonic sensor 4 is turned on, the coil of the relay 37 is energized via the ultrasonic sensor 4 itself, as described above. When the coil of the relay 37 is energized, the contact of the relay 37 is switched to the terminal b, and the energization of the solenoid valve 3 is blocked. As a result, no negative pressure is introduced into any of the negative pressure actuators 68, 69, and the swing levers 53, 54 are maintained in the state shown in FIG. 4, and as a result, the maximum engine speed determined by the opening of the throttle valve The number of revolutions is also more restricted than when traveling outdoors, and finally, the indoor traveling mode as the low-speed traveling mode at the above-described low-speed limit speed (about 5 to 6 km / h) is realized.

Here, when the vehicle goes outdoors in the indoor traveling mode, the indoor traveling mode is continued.
By momentarily operating any one of the cargo handling levers to temporarily turn on the corresponding cargo handling lever switch 34 or 35, the coil 36 of the relay 36 energizes the relay 36 to energize the relay 37 side. It is similar to the first embodiment in that the vehicle is shut off and instantaneously switched to the outdoor traveling mode, which is the high-speed traveling mode.

On the other hand, when any one of the cargo handling levers is operated during the cargo handling operation, the corresponding cargo handling lever switch 34 or 35 is turned on.
When the coil No. 6 is energized, the contact of the relay 36 is switched to the terminal b. As a result, the solenoid of the solenoid valve 2 is energized through the relay 38,
The spool 31 of the solenoid valve 2 is switched to the right offset position. By the switching of the solenoid valve 2, the negative pressure from the vacuum pump is introduced into the negative pressure chamber of the other negative pressure actuator 68, and the rocking lever 54 rocks to the cargo handling mode position FP as shown in FIG. I do. As a result, the opening of the throttle valve tends to open more, and the maximum engine speed determined by the opening of the throttle valve 6 is increased.
At this time, the engine speed is larger than the indoor running mode and the outdoor running mode, and is the largest among the three modes. Therefore, during the cargo handling work, the speed limiting function (the engine speed limiting Work at substantially full power is possible without being restricted by the function).

In the second embodiment, as in the first embodiment, the speed limit driving mode of the vehicle is automatically switched according to whether the vehicle 39 is indoors or outdoors. It has an indoor traveling mode, which is a low-speed traveling mode, and an outdoor traveling mode, which is a high-speed traveling mode, so that the speed limit can be complied with both indoor traveling and outdoor traveling without lowering the cargo handling performance at all. As a result, it is possible to effectively eliminate the irritability of the operator while achieving both improvement in safety and improvement in work efficiency.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing a first embodiment of a vehicle speed control device of the present invention.

FIG. 2 is an explanatory side view of the forklift showing an attached state of the ultrasonic sensor shown in FIG. 1;

FIG. 3 is an explanatory plan view of the forklift showing an attached state of the ultrasonic sensor shown in FIG. 1;

FIG. 4 is a configuration explanatory view showing a second embodiment of the vehicle speed control device of the present invention.

FIG. 5 is an operation explanatory view of the swing lever shown in FIG. 4;

FIG. 6 is an operation explanatory view of the swing lever shown in FIG. 4;

FIG. 7 is an operation explanatory view of the swing lever shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pneumatic governor device 2, 3 ... Solenoid valve 4 ... Ultrasonic sensor (running mode switching means) 5 ... Power supply circuit 6 ... Governor valve 13 ... Governor spring 17 ... Swing lever 18, 19 ... Negative pressure actuator 34, 35 ... Loading lever switch (loading sensor) 51 ... Throttle lever 52 ... Accelerator wire 53,54 ... Swing lever 68,69 ... Negative pressure actuator

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) DB00 DB16 EA03 EA09 EC05

Claims (5)

[Claims] A plurality of vehicle speed limited travel modes based on a throttle system maximum engine speed control function are set separately from the cargo handling mode, and one of the plurality of vehicle speed limited travel modes is set as a travel mode. A vehicle speed control device for a forklift, wherein the vehicle speed control device is selectively switchable. 2. The forklift vehicle speed control device according to claim 1, wherein the selection of the traveling mode is switched by a selection operation of a plurality of negative pressure actuators attached to a throttle system. 3. A cargo handling sensor for detecting that a cargo handling operation has been performed. When the cargo handling sensor is activated, the traveling mode is released to shift to the cargo handling mode. The vehicle speed control device for a forklift according to claim 2, wherein the power mode is a power mode having a higher output than each of the vehicle speed limited driving modes. 4. The forklift vehicle speed control device according to claim 3, wherein the selection of the traveling mode is switched by switching of traveling mode switching means. 5. The running mode switching means comprises a sensor for detecting whether the vehicle itself is indoors or outdoors. When the indoors are detected, the indoor running mode is set, and when the outdoors are detected, the speed limit is set lower than the indoor running mode. The vehicle speed control device for a forklift according to claim 4, wherein a high outdoor traveling mode is selected.