JP2001182576A - Engine speed control device for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a working device caused by erroneously running a vehicle during power take-off in a working vehicle used by taking off power of a vehicular engine. SOLUTION: This engine speed control device is composed of a chassis side accelerator 24 for outputting a running acceleration signal corresponding to a pedaling amount of an accelerator pedal of the vehicle, a mounted side accelerator 23 for outputting a mounted acceleration signal corresponding to an operating condition of the working device, a PTO(power take-off) mechanism 42 for taking off the power of the vehicle engine 41 to a hydraulic unit 52 of the working device and a PTO switch 21 for selecting power take-off, and a control unit 30 for controlling engine speed. The control unit 30 controls so as to make the running acceleration signal ineffective when the PTO switch 21 is turned ON and the engine power is taken off to the hydraulic unit 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine speed control device for a working vehicle, and more particularly, to an engine for a working vehicle that extracts and uses the power of a traveling engine mounted on the vehicle as the driving force of the working device. The present invention relates to a rotation speed control device.

[0002]

2. Description of the Related Art Work vehicles equipped with a working device that uses the power of an engine as a driving force on a vehicle body that is configured to run freely by an engine mounted on the vehicle include, for example, an aerial work vehicle, a crane vehicle, and a road surface. Widely used as excavator. These work vehicles take out the rotational driving force of a vehicle running engine by a PTO (power take-off) mechanism mounted on the vehicle, and drive a hydraulic pump or the like to drive an actuator of a work device on the vehicle body,
For example, it is configured such that a hydraulic cylinder, a hydraulic motor, or the like is operated to perform a desired operation.

For example, when performing an operation using an aerial work vehicle, an operator drives the vehicle, moves to a work site, activates a parking brake with the traveling gear in neutral, and then places the vehicle in a driver's seat. By turning on the provided PTO switch, the rotational driving force of the engine is transmitted to the hydraulic pump of the working device. Then, the outrigger jack or the like is operated by using the hydraulic pressure generated by the hydraulic pump to stably support the vehicle body, and the boom disposed on the vehicle body is operated by turning, raising and lowering, expanding and contracting to a desired height. Do the work.

Here, when the boom is operated as described above, it is preferable to perform proportional control so that the operation speed of the boom changes according to the operator's operation intention, that is, the operation lever input amount. On the other hand, it is not preferable to always rotate the hydraulic pump at full speed to generate the maximum required amount of hydraulic pressure even when no operation is performed, because it wastes fuel. For this reason, the body-side accelerator is provided in the boom operating device so that the engine speed can be changed according to the switch setting and the operation content.

[0005]

In the above-described working vehicle, when the PTO switch is turned on and the driving force of the engine is taken out to the working device,
In general, an indicator that the engine driving force is being taken out is displayed by an indicator lamp or the like provided near the PTO switch in the driver's seat. The vehicle running accelerator (hereinafter referred to as "chassis-side accelerator") and the body-side accelerator are switched depending on the gear position of the running gear and the selected position of the PTO switch, and the body-side accelerator has a neutral running gear and , And is effective only when the PTO switch is on. Therefore, when the traveling gear is other than neutral or when the PTO switch is off, the engine speed is not changed even if the vehicle body accelerator is operated,
Safety in vehicle operation is achieved.

However, in a conventional working vehicle,
Even when the PTO switch is on, when the traveling gear is other than neutral, the chassis-side accelerator functions effectively, so even if the worker does not notice the lighting of the indicator lamp and forgets to turn off the PTO switch. Thus, it was possible to run the vehicle without any trouble. Therefore, the PTO mechanism and the hydraulic pump to which the engine driving force is transmitted are driven to rotate at a rotation speed corresponding to the amount of depression of the accelerator pedal (setting of the chassis-side accelerator) by running the vehicle, and the proportional control valve is fully closed. Despite being in a state, there is a risk that these devices and hydraulic control valves etc. may be damaged due to rotational driving at high speed for a long time, or fluctuations in the rotational speed that cannot be achieved with the body side accelerator setting, etc. There was a problem.

The present invention has been made in view of the above-described problems, and provides an engine speed control device that does not damage a PTO mechanism or a working device even if a worker forgets to turn off a PTO switch. The purpose is to:

[0008]

In order to achieve the above object, according to the present invention, a vehicle body configured to run freely by an engine mounted on a vehicle and an engine speed corresponding to an amount of depression of an accelerator pedal of the vehicle are set. Traveling accelerator setting means (for example, the chassis-side accelerator 24 and the control units 30 and 35 in the embodiment) and a working device (for example, a boom device for a high-altitude working vehicle in the embodiment, A hydraulic unit 52 for operating the boom device), and power take-out means (for example, the PTO switch 21 and the PTO mechanism 42 in the embodiment) configured to be able to take out the power of the vehicle engine as the driving force of the working device; Traveling accelerator restricting means (for example, first accelerator regulating means) for regulating the setting of the engine speed by the traveling accelerator setting means.
The traveling accelerator restricting means is provided when the power of the engine is taken out to the working device by the power take-out means.
The engine speed control device of the work vehicle is configured to perform a regulation that invalidates the setting of the engine speed by the traveling accelerator setting means.

According to the engine speed control device having such a configuration, the traveling accelerator setting means sets the engine speed by the traveling accelerator setting means when the power of the engine is being taken out by the power take-out means. Regulations to invalidate For this reason, even if a worker accidentally depresses the accelerator pedal to drive the vehicle while the power of the engine is being taken out to the working device, the engine speed does not increase and an excessive load acts on the working device. Therefore, there is no risk of damaging the working device. In addition, the operator senses that the engine power is being taken out to the work equipment by the fact that the engine speed does not increase even if the accelerator pedal is depressed, and after the power removal to the work equipment is released, the vehicle travels safely. Can be done.

The traveling accelerator setting means includes a traveling accelerator output device (for example, a chassis-side accelerator 24 in the second embodiment) for outputting an accelerator signal according to the amount of depression of an accelerator pedal, and an accelerator signal. An engine speed control circuit for controlling the engine speed (for example, the control unit 35 in the second embodiment)
The travel accelerator regulating means (for example, the relay switches 26 and 27 in the second embodiment) regulates travel accelerator setting by regulating transmission of an accelerator signal from the travel accelerator output device to the engine speed control circuit. The engine speed control device may be configured to invalidate the setting of the engine speed by the means. According to such a configuration, for example, in a case where an interlock connection terminal or the like is not provided in an engine speed control circuit of a vehicle or in a case where a control flow of an engine speed control device cannot be easily changed. Even in this case, it is possible to easily and easily configure an engine speed control device that can obtain the same effect as described above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an engine speed control apparatus according to the present invention will be described below with reference to the drawings. First, FIG. 4 shows an aerial work vehicle 1 including the engine speed control device according to the present invention.
The configuration of the aerial work vehicle 1 will be described. The aerial work vehicle 1 has a driving cabin 2 in front of the vehicle.
A swivel 4 configured to be able to swing horizontally in the horizontal direction is provided with respect to the vehicle body 2. The boom 5 is pivoted.

The boom 5 includes a base boom 5a, an intermediate boom 5b, and a distal boom 5c pivotally attached to the upper end of the swivel base 4. Each of the booms 5 is inserted into a telescope shape and disposed inside the boom 5. The telescopic cylinder 13 is configured to be able to expand and contract freely by the operation of the telescopic cylinder 13. At the tip of the tip boom 5c, there is provided a vertical post 6 which is always kept vertical regardless of the elevation angle of the boom 5 by the operation of a leveling cylinder (not shown). The arm 7 is configured so as to be capable of pivoting (referred to swinging) around the vertical post 6 by the operation of the arm 7.
The work table 8 is provided via the.

The workbench 8 is provided with a boom operating device 10 for operating the boom 5, and transmits a command signal corresponding to an operation command of an operator who is boarding the workbench 8 under predetermined conditions. 2 is output to the hydraulic unit 52 disposed in the second unit 2. The hydraulic unit 52 is a hydraulic oil supply unit that generates a hydraulic pressure by a hydraulic pump disposed in the unit and supplies the generated hydraulic pressure to each hydraulic actuator such as the swing motor 11, the up-and-down cylinder 12, and the telescopic cylinder 13. In addition, based on a command signal from the boom operating device 10, the opening degree of a control valve provided for each hydraulic actuator is proportionally controlled to operate these hydraulic actuators.

For this reason, the operator who gets on the worktable 8 can operate the operating device 10 to freely move the boom 5 in accordance with the amount of operation of the operating lever, move up and down, expand and contract, and the like. Thus, the work table 8 can be moved to an arbitrary height to perform a desired height work. The vertical post 6 is provided with a winch 18 for facilitating lifting of heavy objects at a high place. Also, when the boom 5 is operated to pivot or extend, or when a heavy object is lifted by the winch 18, the boom 5 acts on the aerial work vehicle 1 to resist the overturning moment that attempts to overturn the vehicle body 3. In order to stably support the vehicle body 3, the hydraulically driven outrigger jack 1
7, 17,... Are provided.

In the aerial work vehicle 1 configured as described above, an operator drives the vehicle to move to a target work site,
After the outrigger jacks 17, 17,... Are extended to stably support the body 3, the telescopic boom 5 is operated by operating on the workbench 8 and operating the boom operating device 10, such as turning, raising and lowering, and telescopic movement. The work table 8 can be moved to a desired height to perform work at a height.

As described above, the hydraulic unit 52 is a hydraulic oil supply source for supplying hydraulic oil to a working device provided on the vehicle body, and is operated using the rotational driving force of the vehicle engine. For this reason, the transmission section of the vehicle engine is equipped with a PTO (power take-off) mechanism for transmitting or blocking the rotational driving force of the engine to the hydraulic unit 52. An electromagnetic clutch is built in the PTO mechanism. When a PTO switch (21) disposed in the driving cabin 2 is turned on during operation, the electromagnetic clutch is engaged to apply the rotational driving force of the engine to the hydraulic unit. 52 to rotate the hydraulic pump.

In the aerial work vehicle 1 configured as described above,
When the vehicle is running, the power of the engine is transmitted to the traveling device to control the engine speed according to the amount of depression of the accelerator pedal, and at the time of work, the PTO switch is turned on to transmit the power of the engine to the hydraulic unit 52, It is necessary to control the engine speed according to the operation of the boom operating device 10. For this reason, the aerial work vehicle 1
Is equipped with an engine speed control device for controlling the engine speed in accordance with each of these conditions.

FIG. 1 is a block diagram showing a first preferred embodiment of an engine speed control device according to the present invention, which will be described below with reference to FIG. This device includes a PTO switch 21 described above, a gear position detector 22 for detecting the position of a traveling gear, a chassis-side accelerator 2
4, body side accelerator 23, control unit 30,
It is composed of a PTO mechanism 42 and the like.

The gear position detector 22 is a detector for detecting the position of the running gear. In this embodiment, the gear position detector 22 detects whether the gear is at the neutral position and outputs the result to the control unit 30. The chassis-side accelerator 24 is a detector that detects the amount of depression of an accelerator pedal in the driving cabin 2. For example, the amount of depression of the accelerator pedal is directly or indirectly detected by a potentiometer or an encoder via a throttle wire or the like. The traveling accelerator signal corresponding to this is output to the control unit 30 as a voltage output, a current output, or a light output.

The body side accelerator 23 is provided with the boom operating device 1.
0, and the selection of an accelerator select switch and the boom operation lever provided on the panel of the boom operation device 10 under permissible conditions described later in detail.
A body accelerator signal corresponding to the operation state (both not shown) is output to the control unit 30 in the same manner as the traveling accelerator signal. The accelerator select switch has three stages of high, medium, and low speed accelerator ranges, and is appropriately selected according to the work content. When the boom operation lever is not operated in each range, a bodywork accelerator signal corresponding to the idling speed is output, and when the boom operation lever is operated (closed), the accelerator selected by the accelerator select switch is output. A bodywork accelerator signal corresponding to the range is output. For example, when the medium-speed rotation range is selected, when the operation lever is turned on, a bodywork accelerator signal corresponding to the medium-speed rotation range is output.

The control unit 30 includes an on / off state of the PTO switch 21 and a gear position detector 2.
2, the traveling accelerator signal input from the chassis-side accelerator 24 or the body accelerator signal input from the body-side accelerator 23 is validated in accordance with the combination with the selected position of the vehicle traveling gear detected by the step 2. Judge
The rotation speed of the engine 41 is controlled based on this determination.

FIG. 3 shows which accelerator signal is made effective by the control unit 30 by the combination of the on / off state of the PTO switch 21 and the selected position of the vehicle running gear detected by the gear position detector 22. Are collectively shown as a table. As is clear from FIG. 3, when the PTO switch 21 is off, the vehicle body accelerator signal set by the vehicle body accelerator 23 is invalid regardless of the position of the traveling gear, and is set by the chassis side accelerator 24. Only the traveling accelerator signal is valid.

When the PTO switch 21 is ON, that is, when the rotational driving force of the engine 41 is being extracted to the hydraulic unit 52, the traveling accelerator signal 24 set by the chassis accelerator is invalid regardless of the traveling gear position. It is. At this time, the body accelerator signal is not immediately valid, and additionally, the body accelerator signal is valid only when the traveling gear is in the neutral position. And as is clear from the figure, PTO
Even if the switch 21 is on, when the traveling gear is other than neutral, both the traveling accelerator signal and the bodywork accelerator signal are invalid.

For this reason, during normal running with the PTO switch 21 turned off, the engine speed does not change even if a body accelerator signal is input due to an abnormality of the body accelerator 23 or the like, and the safety of vehicle operation is improved. Secured. When the PTO switch is turned on during the operation and the traveling gear is in the neutral position, only the body accelerator signal from the body-side accelerator 23 is valid, and the traveling accelerator signal is invalid. Therefore, the working device can be used safely.

Further, when the travel gear is set to a travel range other than the neutral range while the PTO switch 21 is on, both the vehicle body accelerator signal from the vehicle body accelerator 23 and the vehicle accelerator signal from the chassis side accelerator 24 are invalid. It is said. Therefore, in a state where the rotational driving force of the engine 41 is transmitted to the hydraulic unit 52, the engine speed does not increase even if the accelerator pedal is depressed in order to make the vehicle run unnoticed, and the operation lever is turned on. Even if the engine speed does not change. Therefore,
The operator can detect that the PTO switch 21 is on and correct it, and also prevent a situation such as erroneously driving the vehicle at high speed to damage the PTO mechanism or the hydraulic pump. it can.

Next, FIG. 2 is a block diagram showing a second preferred embodiment of the engine speed control device according to the present invention, which will be described below with reference to FIG. In this device, the accelerator signal input terminal of the control unit 35 is 1
In a case where the selection of the accelerator signal and the determination of the condition cannot be performed in the control unit using only the terminal, the same operation as the above-described engine speed control device can be performed.

This engine speed control apparatus is the same as the PTO switch 21 described in the first embodiment.
And a PTO mechanism 42, a gear position detector 22 for detecting the position of a traveling gear, a chassis-side accelerator 24, a body-side accelerator 23, and other components having similar functions, and a control unit 35 for controlling the engine speed. , Idling resistance 25, relay switches 26, 2
7 and the like. In FIG. 2, the accelerator signal input circuit to the control unit 35 is shown electrically.

The gear position detector 22 outputs a voltage output of +12 V to the relay R ₁ of the relay switch 26 when the running gear of the vehicle is in neutral, and outputs 0 V when another gear is selected. . PTO switch 21 provides a voltage output of + 12V when the switch is on the relay R ₂ of the relay R ₁ and the relay switch 27 of the relay switch 26, PTO switch 21 outputs a 0V when OFF.

The relay R ₁ in the relay switch 26 (a driving gear is neutral and, PTO switch is when on) when the output signal are both + 12V from the gear position detector 22 and the PTO switch 21 switch 26 only Are connected by switching between A and C shown in the figure, and the connection between A and B is maintained under other conditions. Relay R ₂ in the relay switch 27 is connected by switching between D-F shown in the figure the contact of the switch 27 when the output signal is + 12V from PTO switch 21 (when PTO switch is on), the PTO switch When it is off, the connection between DE is maintained.

When the PTO switch 21 is turned off, the contact positions of the two relay switches 26 and 27 in the engine speed control device having the above-described configuration are set to the contact positions (A) shown in FIG. 2 regardless of the position of the traveling gear. -B and D
-E), and the traveling accelerator signal set by the chassis-side accelerator 24 (potentiometer) is input to the accelerator signal input terminal ACC of the control unit 35. At this time, since the connection of the vehicle body-side accelerator 23 is interrupted by the relay switch 26, the engine speed does not change even if the setting is changed.

[0031] When the PTO switch 21 is turned on, first the relay R ₂ in the relay switch 27 +12
A voltage of V is applied, and the connection contact is switched between DF. When the traveling gear is in neutral, the PTO
Contact of the relay switch 26 for voltage applied from the switch 21 and the gear position detector 22 to the relay R ₁ are both + 12V is switched between A-C. Therefore, at this time, a bodywork accelerator signal set by the bodyside accelerator 23 (potentiometer) is input to the accelerator signal input terminal ACC of the control unit 35. Since the connection of the chassis-side accelerator 24 is cut off by the relay switch 26, the engine speed does not change even if the accelerator pedal is depressed.

[0032] be PTO switch 21 is a one, the voltage position of the running gear which is applied from the gear position detector 22 and in the other cases the neutral relay R ₁ is 0
V. For this reason, the connection contact of the relay switch 26 is between A and B, and the connection contact of the relay switch 27 is between D and F. The accelerator signal input terminal ACC of the control unit 35 receives an accelerator signal set by the idling resistor 25. Is done. The idling resistor 25 is a fixed resistor for setting an accelerator signal corresponding to the idling speed, and the engine speed is fixedly set to the idling speed. At this time, the connection of the body-side accelerator 23 is interrupted by the relay switch 26 and the connection of the chassis-side accelerator 24 is interrupted by the relay switch 27. Therefore, operating any of these accelerators does not change the engine speed.

As described above, the same engine speed control as that shown in FIG. 3 can be performed by the engine speed control device having the configuration shown in FIG. For this reason, during normal traveling in which the PTO switch 21 is turned off, only the chassis-side accelerator 24 is valid, and the body-side accelerator 23
The engine speed does not change even if an abnormality occurs. Therefore, safety during vehicle operation is ensured. Also,
When the PTO switch 21 is turned on and the traveling gear is in neutral, only the vehicle body-side accelerator 23 is valid, and the engine speed does not change even if the accelerator pedal is depressed. Therefore, the working device can be used safely.

Further, when the running gear is put into a running range other than the neutral range with the PTO switch 21 turned on, the vehicle body side accelerator 23 and the chassis side accelerator 24
Are cut off and the engine speed is fixed at the idling speed. Therefore, in a state where the rotational driving force of the engine 41 is transmitted to the hydraulic unit 52, the engine speed does not increase even if the accelerator pedal is depressed in order to run the vehicle without noticing this, and the operation lever is turned on. Even if the engine speed does not change. Therefore, the operator can sense that the PTO switch 21 is on and correct it, and also prevent a situation such as erroneous running of the vehicle at high speed to damage the PTO mechanism or the hydraulic pump. be able to.

In the above, for simplicity of explanation, the case where the rotational driving force of the vehicle engine is directly taken out as the driving force of the hydraulic pump for operating the working device on the vehicle body has been described. Can be similarly implemented in other embodiments as long as the power of the vehicle engine is taken out and used as the driving force of the working device. For example, an embodiment in which a rotational driving force of an engine is taken out by a PTO switch or the like to rotate a generator and a working device on a vehicle body is operated by using the generated power, or a hydraulic pump is generated by using the generated power. The same configuration can also be applied to an embodiment in which is rotated, an embodiment in which generated power is stored in a battery, and the like. And in such an embodiment, PT
The same effect as in the above embodiment can be obtained in that there is no possibility that the vehicle may be erroneously driven while the O-switch is turned on to damage the generator.

[0036]

As described above, according to the present invention, in a working vehicle having a working device on a vehicle body and configured to be able to run freely by an engine mounted on the vehicle, the working vehicle according to the depression amount of the accelerator pedal of the vehicle. Traveling accelerator setting means for setting the engine speed, power take-out means configured to be able to take out the power of the vehicle engine as the driving force of the working device arranged on the vehicle body, and the engine speed by the traveling accelerator setting means. Traveling accelerator regulating means for regulating the setting, wherein the traveling accelerator regulating means invalidates the setting of the engine speed by the traveling accelerator setting means when the power of the engine is being taken out to the working device by the power take-out means. Is configured to perform the engine speed control of the work vehicle.

According to the engine speed control device having the above-described structure, even if the operator accidentally depresses the accelerator pedal to run the vehicle while the power of the vehicle engine is being taken out to the work device, the engine speed can be reduced. Since the rotation speed does not increase, an excessive load does not act on the working device, and therefore, there is no risk of damaging the working device. In addition, the operator senses that the engine power is being taken out to the work equipment by the fact that the engine speed does not increase even if the accelerator pedal is depressed, and after the power removal to the work equipment is released, the vehicle travels safely. Can be done.

The traveling accelerator setting means comprises a traveling accelerator output device for outputting an accelerator signal according to the amount of depression of an accelerator pedal, and an engine speed control circuit for controlling the engine speed based on the accelerator signal. The travel accelerator restricting means controls the engine speed control device to invalidate the setting of the engine speed by the travel accelerator setting means by restricting transmission of an accelerator signal from the travel accelerator output device to the engine speed control circuit. It can also be configured. According to such a configuration,
For example, even when the engine speed control circuit of the vehicle is not provided with an interlock connection terminal or the like, or when the control flow of the engine speed control device cannot be easily changed, it is simple and easy. An engine speed control device that achieves the same effects as described above can be configured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first preferred embodiment of a work vehicle engine speed control device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a second preferred embodiment of the engine speed control device for a work vehicle according to the present invention.

FIG. 3 is a table for explaining the operation of the engine speed control device according to the first and second embodiments.

FIG. 4 is an explanatory diagram for explaining a configuration of a work vehicle (a high-place work vehicle) including the engine speed control device.

[Explanation of symbols]

Reference Signs List 1 aerial work vehicle (work vehicle) 3 body 4-10 boom device (work device, 4 turning table, 5 boom, 6 vertical post, 8 work table, 10 boom operating device, etc.) 11-13 hydraulic actuator (work device, DESCRIPTION OF REFERENCE NUMERALS 11 swing motor, 12 undulating cylinder, 13 telescopic cylinder, etc. 21 PTO switch (power take-out means) 23 body-side accelerator (body-holding accelerator setting means) 24 chassis-side accelerator (traveling accelerator setting means, traveling accelerator output device) 26, 27 relay switch (travel accelerator restriction means) 30 control unit (body accelerator setting means,
Traveling accelerator setting means, traveling accelerator regulating means) 35 control unit (engine speed control circuit) 41 engine 42 PTO mechanism (power take-out means) 52 hydraulic unit (working device)

Claims (2)

[Claims] 1. A vehicle body configured to run freely by an engine mounted on a vehicle, traveling accelerator setting means for setting an engine speed according to an amount of depression of an accelerator pedal of the vehicle, and disposed on the vehicle body Operating device, a power take-out unit configured to be able to take out the power of the engine as a driving force of the working device, and a traveling accelerator regulating unit that regulates the setting of the engine speed by the traveling accelerator setting unit. The driving accelerator restricting means performs restriction of invalidating the setting of the engine speed by the driving accelerator setting means when the power of the engine is being taken out to the working device by the power take-out means. The engine speed control device of the working vehicle. 2. The traveling accelerator setting device includes: a traveling accelerator output device that outputs an accelerator signal according to a depression amount of an accelerator pedal; and an engine speed control that controls a revolution speed of the engine based on the accelerator signal. The traveling accelerator restricting means invalidates the setting of the engine speed by the traveling accelerator setting means by restricting transmission of an accelerator signal from the traveling accelerator output device to the engine speed control circuit. The engine speed control device for a working vehicle according to claim 1, wherein: