WO2011135846A1

WO2011135846A1 - Asphalt finisher

Info

Publication number: WO2011135846A1
Application number: PCT/JP2011/002443
Authority: WO
Inventors: 哲男前田
Original assignee: 範多機械株式会社
Priority date: 2010-04-27
Filing date: 2011-04-26
Publication date: 2011-11-03
Also published as: JP5066664B2; JPWO2011135846A1

Abstract

An asphalt finisher is provided with: an engine comprising a travel mechanism, a conveyor, a screw, and various screed mechanisms; a generator; a plurality of motors; an adjustment part; and a plurality of inverters. The generator generates electricity through the driving of the engine. Each motor drives a respective mechanism using power from the generator. The adjustment part adjusts the output voltage of the generator in such a manner that the output voltage of the generator attains a voltage within a prescribed range, even when a first rotational state exists in which the engine is at a relatively low engine speed, or when a second rotational state exists in which the engine speed is at a relatively high engine speed. Each inverter converts the output from the generator, the voltage of which has been adjusted by the adjustment part, to the desired frequency and supplies the output to each motor.

Description

Road paving machine

The present invention relates to a road paving machine for paving an asphalt road such as an asphalt finisher, a re-paver, a remixer, and more particularly to a road paving machine for electrically driving an actuator using a generator.

Conventionally, in an asphalt finisher, each actuator (each mechanism) such as a traveling wheel, a conveyor, and a screw is driven by hydraulic pressure. FIG. 17 is a diagram showing a configuration of a conventional asphalt finisher. As shown in FIG. 17, the asphalt finisher 101 is mainly composed of a vehicle body 102 and a screed 111, and the vehicle body 102 and the screed 111 are connected by a leveling arm 108. A hopper 103, traveling wheels (front wheels 104 and rear wheels 105), a conveyor 106, and screws 107 are attached to the vehicle body 102. Further, an LPG cylinder 109 is mounted on the vehicle body 102. The screed 111 includes a vibrator 113 and an LPG burner 112.

The energy transmission system in the conventional asphalt finisher is a hydraulic system using a diesel engine as a power source. That is, the main actuators such as the

traveling wheels

104 and 105, the conveyor 106, and the screw 107 and the vibrator 113 are driven by a hydraulic motor that is driven by a hydraulic pump that uses a diesel engine as a power source. The screed 111 is heated by LP gas combustion. That is, the LPG burner 112 receives the supply of LP gas from the LPG cylinder 109 and burns and heats the screed 11 (more specifically, the ground contact surface (screed plate) of the screed 111).

Note that it is proposed that the actuator is electrically driven in a construction machine that is not a road paving machine. For example, Patent Literature 1 describes that a power generator and a battery are mounted on an excavator, and an actuator is driven by power from a battery that stores power generated by the power generator or regenerative power. In addition, regarding the heating method of a screed plate, performing electrical heating with respect to a screed plate is also considered (for example, refer patent document 2).

JP 2001-16891 A Special table 2003-519733 gazette

In the conventional asphalt finisher, since the main actuator is driven by hydraulic pressure as described above, the power transmission efficiency is reduced in the hydraulic control circuit. Specifically, efficiency loss due to sliding resistance of hydraulic pump, fluid resistance of pressure oil, pressure oil passage resistance in pipes and control valves, etc. It was deteriorating. Furthermore, the fact that energy is required to cool the heat generation of the hydraulic oil due to this power loss has also caused the deterioration of energy efficiency.

As described above, the conventional asphalt finisher has the problem that the energy efficiency is poor due to the hydraulic system, and the carbon dioxide emission increases accordingly. In addition, the conventional asphalt finisher has a problem that maintenance costs are required for maintenance and replacement of hydraulic equipment such as a hydraulic pump and a hydraulic motor and hydraulic oil.

In addition, although it is disclosed by the said patent document 1 to electrically drive each actuator of a shovel, it is not disclosed regarding road paving machines, such as an asphalt finisher. Therefore, regarding the power generation by the generator or the driving of each actuator, the control method of Patent Document 1 cannot be directly applied to the control of the asphalt finisher. It cannot be electrically driven efficiently. Moreover, although the said patent document 2 describes performing electrical heating with respect to a screed plate, since it is not electrically driven about another actuator, the subject mentioned above cannot be solved.

Therefore, an object of the present invention is to improve energy efficiency and reduce carbon dioxide emissions in road paving machines such as asphalt finishers.

The present invention employs the following configurations (1) to (19) in order to solve the above problems.

(1)
The present invention is a road paving machine having a traveling mechanism, a conveyor, a screw, and a screed mechanism and paving an asphalt road. The road paving machine includes an engine, a generator, a plurality of motors, an adjustment unit, and a plurality of inverters. The generator generates electricity by driving the engine. Each motor drives each mechanism with electric power from a generator. The adjustment unit is configured to adjust the output voltage of the generator in both the case where the engine is in the first rotation state where the engine speed is relatively low and the case where the engine is in the second rotation state where the engine speed is relatively high. The output voltage of the generator is adjusted so that the voltage is within a predetermined range. Each inverter converts the output of the generator whose voltage has been adjusted by the adjustment unit into a desired frequency and supplies it to each motor.

The “adjusting unit” may adjust the output voltage by changing the power generation characteristics of the generator, as in the embodiments and the fourth modification described later. As in the seventh modification, the output voltage may be adjusted by processing the output of the generator.

According to the configuration of (1) above, the road paving machine can electrically drive each mechanism such as a traveling mechanism, a conveyor, and a screw. According to this, compared with the conventional system which drives each mechanism with oil_pressure | hydraulic, while being able to achieve energy saving, the discharge | emission amount of a carbon dioxide can be decreased. Furthermore, according to the configuration of (1) above, even if the output voltage of the generator varies according to the engine speed, the voltage input to each inverter is adjusted by the adjustment unit. Therefore, each inverter can be operated appropriately, and each motor can be correctly controlled by each inverter.

(2)
The adjustment unit may be connected to the output side of the generator and may convert the input voltage into a voltage within a predetermined range and output the voltage.

According to the configuration of (2) above, the output voltage of the generator is converted into a voltage within a predetermined range by the adjustment unit and input to each inverter. Therefore, in both the case where the engine is in the first rotation state and the case where the engine is in the second rotation state, a voltage within a predetermined range is input to each inverter, so that each inverter can be appropriately operated. .

(3)
The road pavement machine may further include a rectifying unit that converts AC electricity output from the generator into DC electricity. At this time, the adjustment unit includes a constant voltage device that converts the voltage of DC electricity into a voltage within a predetermined range.

According to the configuration of (3) above, the output voltage of the generator can be easily adjusted by the constant voltage device. In addition, the output voltage of the generator can be boosted and stepped down by a constant voltage device, so that it is possible to cope with the case where the engine speed fluctuates for some reason, and a voltage within a predetermined range is input to each inverter. can do. In addition, since the DC voltage is converted by the constant voltage device, the voltage can be adjusted with higher accuracy than when the AC voltage is converted (for example, sixth and seventh modifications described later).

(4)
The adjustment unit may adjust the output voltage of the generator by changing the power generation characteristics of the generator between when the engine is in the first rotation state and when the engine is in the second rotation state. The adjustment unit may change the power generation characteristics by changing the number of turns of the generator coil as in the embodiment described later, or may flow through the field coil as in the fourth modification. The power generation characteristics may be changed by changing the current.

According to the configuration of (4) above, the output voltage of the generator can be adjusted by changing the power generation characteristics of the generator by the adjustment unit, and an appropriate voltage can be input to each inverter. it can.

(5)
The road paving machine may further include a switching unit. The switching unit is configured such that when the engine is in the first rotation state, the output of the generator is input to each inverter via the adjustment unit, and when the engine is in the second rotation state, the output of the generator is The power transmission path from the generator to each inverter is switched so that it is input to each inverter without going through. At this time, the generator outputs a voltage within a predetermined range when the engine is in the second rotation state. The adjustment unit converts the output voltage of the generator when the engine is in the second rotation state into a voltage within a predetermined range.

According to the configuration of (5) above, since the output voltage of the generator is adjusted by the adjustment unit when the engine is in the first rotation state, an appropriate voltage can be input to each inverter. On the other hand, since the generator outputs a voltage within a predetermined range when the engine is in the second rotation state, an appropriate voltage is input to each inverter by inputting the output voltage of the generator as it is to each inverter. be able to. That is, in the case of both the case where the engine is in the first rotation state and the case where the engine is in the second rotation state, the inverter of each inverter in the case of the configuration of the above (5) as well as the configurations of (1) to (4). An appropriate voltage can be input. Further, according to the configuration of (5) above, the adjustment unit does not have to correspond to the output voltage when the engine is in a high rotation state, so that the adjustment unit can be configured more simply.

(6)
A rectifier that converts alternating current electricity output from the generator into direct current electricity;
The switching unit switches the power transmission path of DC electricity,
The road paving machine according to claim 5, wherein the adjustment unit includes a booster that boosts the voltage of DC electricity to a voltage within a predetermined range.

According to the configuration of (6) above, the output voltage of the generator is boosted by the booster and input to each inverter, so that an appropriate voltage can be input to each inverter.
Moreover, according to the configuration of (6) above, the adjustment unit can be made simpler than the configuration of (3) above. Further, similarly to the configuration of (3) above, voltage adjustment can be performed with higher accuracy than in the case of converting an AC voltage.

(7)
The adjustment unit may include a transformer that transforms AC electricity output from the generator.

According to the configuration of (7) above, the output voltage of the generator can be easily adjusted by the transformer.

(8)
The road paving machine may further include an automatic voltage regulator that controls the field current of the generator based on the output voltage of the generator.

According to the configuration of (8) above, the output voltage of the generator is adjusted not only by the transformer but also by an automatic voltage regulator. Therefore, the output voltage can be adjusted with higher accuracy than when only the transformer is used.

(9)
The road paving machine may further include a heating device and a control device. The heating device heats the screed by the electric power generated by the generator. The control device controls the operation of each inverter and heating device. The generator can be switched between a first mode and a second mode having different power generation characteristics. Here, the first mode is a mode in which the generated power when the engine is at the first rotation speed is larger than that in the second mode. The second mode is a mode in which the generated power is larger than that in the first mode when the engine has a second rotation speed lower than the first rotation speed.

The generator can output predetermined first power when the engine is at the first rotation speed, and can output second power when the engine is at a second rotation speed lower than the first rotation speed. It may be possible to switch between the first mode and the second mode in which the third power larger than the second power can be output when the engine is at the second rotation speed. Here, the “first mode” and the “second mode” specify the property (characteristic) of the generator, and do not specify the actual operation of the generator. That is, when the generator is set to the first mode, it is only necessary that the generator can output the second electric power at the second rotational speed, and actually the second electric power at the second rotational speed is the second. It may operate so that power is not output. In other words, the generator is controlled so as not to output the second power in the first mode as a result of being always set to the second mode at the second rotational speed as in the embodiment described later. May be.

In the above, the value of the second power in the first mode may be zero. That is, in the first mode, it is not necessary to generate power when the rotation speed is the second. In other words, the generator is capable of generating power at the first power generation characteristic capable of generating power at the first rotational speed at the time of high-speed rotation of the engine, and at the second rotational speed at the time of low-speed rotation of the engine, and It may be possible to switch between the second power generation characteristic in which the generated power at the rotation speed of 2 is larger than the first power generation characteristic.

According to the configuration of (9) above, the generator can switch between two modes that are adapted to different rotational speeds. Therefore, by changing the mode according to the rotational speed of the engine, the power generation efficiency can be improved. It is possible to improve the energy saving.

(10)
The generator may include a generator configured such that the number of coil turns is relatively small in the first mode and the number of coil turns is relatively large in the second mode.

According to the configuration of (10) above, the power generation characteristics (mode) of the generator can be easily switched by changing the number of turns of the coil.

(11)
In the second mode, the generator may output at least power necessary for the operation of the heating device as the third power.

According to the configuration of (11) above, the heating device can be operated even when the engine is in a low rotation state. Here, regarding the road pavement machine, as an actual usage mode, a usage mode in which the heating device is operated at the time of preparation for pavement construction can be considered. According to the configuration of (3) above, the engine can be kept in a low rotation state when used in such a usage mode. That is, at the time of preparation for pavement construction, it is possible to save energy by setting the engine to a low rotation state, and it is possible to reduce noise during preparation for pavement construction.

(12)
The road paving machine may further include a detection unit that detects the rotational speed of the engine. At this time, the control device switches between the first mode and the second mode according to the detection result of the detection unit.

According to the configuration of (12) above, the generator mode is automatically switched according to whether the engine is in a high rotation state or a low rotation state. According to this, it is not necessary for the user (operator) to manually operate the mode of the generator, the operation can be facilitated, and power generation can be performed in an optimal mode according to the engine speed. .

(13)
The control device may control the operation of each motor and the heating device so that the total power consumption of each motor and the heating device does not exceed the generated power of the generator.

According to the configuration of (13) above, the operation of each motor and heating device is controlled so as not to exceed the amount of power generated by the generator. Therefore, it is possible to prevent an excessive load from being applied to the generator, and it is possible to stably operate each actuator.

(14)
When starting any two or more of the motors and the heating devices, the control device may start the motors and the heating devices with different start timings.

According to the configuration of (14) above, the power consumption of a plurality of actuators can be dispersed in time even if the power consumption temporarily increases at the time of actuator activation by shifting the timing of starting activation. . Therefore, it is possible to easily prevent the total power consumption from exceeding the power of the generator.

(15)
The control device may temporarily stop or reduce the power supply to the heating device when starting at least one of the motors.

According to the configuration of (15) above, heating by the heating device is temporarily stopped while the motor is started. According to this, when starting a motor, it can prevent more reliably that total power consumption exceeds the electric power of a generator.

(16)
The control device calculates the total power consumption of each motor and heating device, and when the total power consumption is equal to or greater than a predetermined value, the power supplied to at least one of each motor and heating device may be stopped or reduced. Good.

According to the configuration of (16) above, it is possible to reliably prevent the total power consumption of each motor and heating device from exceeding the power generated by the generator by appropriately setting the predetermined value.

(17)
The road pavement machine may further include a vibrator for vibrating the screed and a vibrator motor that drives the vibrator with electric power from a generator.

According to the configuration of (17) above, since the vibrator is electrically driven, the energy efficiency can be further improved as compared with the case of hydraulic driving. Further, since the vibrator is electrically controlled, the vibration frequency of the vibrator can be controlled with higher accuracy. Furthermore, since the hydraulic piping to the vibrator becomes unnecessary, the screed mechanism can be simplified.

(18)
The road paving machine may further include a power supply terminal for obtaining external power. At this time, the control device can switch between power from the generator and power from the power supply terminal.

According to the configuration of (18) above, each actuator and heating device can be driven by external power. When an external power source is used, compared with the case where power is generated by a generator by an engine (generally), electric conversion efficiency is good and carbon dioxide emissions can be reduced. Therefore, in a situation where it can be connected to an external power source (for example, when the road paving machine is stopped), it is possible to save energy and to discharge carbon dioxide by using the power supplied from the external power source. Can be further reduced.

(19)
Further, the present invention may be a road paving machine having a traveling mechanism, a conveyor, a screw, and a screed mechanism and paving an asphalt road. The road paving machine includes an engine, a generator, a plurality of motors, a heating device, and a control device. The generator generates electricity by driving the engine. Each motor drives each mechanism with electric power from a generator. The heating device heats the screed by the electric power generated by the generator. The control device controls the operation of each inverter and heating device. The control device controls the operation of each motor and heating device so that the total power consumption of each motor and heating device does not exceed the power generated by the generator.

According to the configuration of (19) above, the road paving machine can electrically drive each mechanism such as a traveling mechanism, a conveyor, and a screw, as in the configuration of (1) above. Therefore, energy saving can be achieved and the amount of carbon dioxide emission can be reduced as compared with the conventional method in which each mechanism is driven by hydraulic pressure. Furthermore, according to the configuration of (19), the operation of each motor and heating device is controlled so as not to exceed the amount of power generated by the generator. Therefore, it is possible to prevent an excessive load from being applied to the generator, and it is possible to stably operate each actuator.

According to the present invention, the main actuator and the heating device are electrically driven to save energy and to reduce carbon dioxide emission. Further, according to the present invention, by using a generator capable of switching between two modes adapted to different rotational speeds, the power generation efficiency can be improved, and further energy saving can be achieved.

Equipment configuration diagram of asphalt finisher according to this embodiment The figure which shows the electric constitution of the asphalt finisher which concerns on this embodiment The figure explaining the difference of the current at the time of motor starting with and without the inverter The figure which shows the internal electrical wiring of the generator shown in FIG. The flowchart which shows the flow of a process in the controller 25 shown in FIG. Sub-flowchart showing the detailed processing of step S4 shown in FIG. Sub-flowchart showing detailed processing of step S6 shown in FIG. Sub-flowchart showing the detailed processing of step S21 shown in FIG. The figure which shows the power consumption in the case of starting a some control object apparatus The figure which shows the electric constitution of the asphalt finisher which concerns on a 1st modification. The figure which shows the electrical structure of the asphalt finisher which concerns on a 2nd modification. The figure which shows the electric constitution of the asphalt finisher which concerns on a 3rd modification. The figure which shows the electric constitution of the asphalt finisher which concerns on a 4th modification The figure which shows the electric constitution of the asphalt finisher which concerns on a 5th modification The figure which shows the electric constitution of the asphalt finisher which concerns on a 6th modification The figure which shows the electric constitution of the asphalt finisher which concerns on a 7th modification Diagram showing the structure of a conventional asphalt finisher

Hereinafter, an asphalt finisher according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an equipment configuration diagram of an asphalt finisher according to the present embodiment. The asphalt finisher 1 according to the present embodiment reduces energy consumption and safety by electrically driving main actuators (traveling mechanism, conveyor, screw) and electrically heating the screed. It can be raised.

(External structure of asphalt finisher according to this embodiment)
First, the external configuration of the asphalt finisher according to the present embodiment will be described. In FIG. 1, the asphalt finisher 1 includes a vehicle body 2 and a screed 11. The vehicle body 2 includes a hopper 3, a front wheel 4, a rear wheel 5, a conveyor 6, and a screw 7. The front wheels 4 and the rear wheels 5 are traveling mechanisms of the asphalt finisher 1, the front wheels 4 are steering wheels, and the rear wheels 5 are drive wheels. The hopper 3 is provided in the front part (left side in FIG. 1) of the vehicle body 2 and receives asphalt mixture from the supply side (dump truck or the like). The conveyor 6 is provided from the lower side of the hopper 3 to the rear part of the vehicle body 2 and conveys the asphalt mixture received by the hopper 3 to the rear. The screw 7 diffuses the asphalt mixture conveyed by the conveyor 6 to the road surface while widening in the left-right direction. These members 3 to 7 may be the same as the conventional asphalt finisher.

The screed 11 is connected to the vehicle body 2 by a leveling arm 8 so as to be movable up and down. The screed 11 has a heating device 12 and a vibrator 13. The heating device 12 heats the lower surface (screed plate) of the screed 11. In the present embodiment, the heating device 12 is typically an electric heater, which is a heating unit that heats with electric power. The vibrator 13 vibrates the screed 11.

With the above configuration, the asphalt finisher 1 diffuses the asphalt mixture supplied to the hopper 3 from the rear screw 7 to the road surface via the conveyor 6, and rolls the diffused asphalt mixture uniformly and flatly by the screed 11. Paving.

The configuration shown in FIG. 1 is an example, and the present invention can be applied to any road paving machine including a main mechanism and a heating device including a traveling mechanism, a conveyor, and a screw. For example, the traveling mechanism may be a crawler type instead of a wheel type, and may include an actuator other than the main actuator.

(Internal structure of asphalt finisher)
Next, the internal configuration of the asphalt finisher according to the present embodiment will be described with reference to FIGS. FIG. 2 is a diagram illustrating an electrical configuration of the asphalt finisher according to the present embodiment. As shown in FIG. 2, the asphalt finisher 1 includes an engine 21, a generator 22, an operation panel 23, a control box 24, motors 30 to 32 b, and a differential gear 33.

The engine 21 as a power source is mechanically connected to the generator 22 and rotates the generator 22. The engine 21 is typically a diesel engine. In this embodiment, the engine 21 is driven in a high rotation state or a low rotation state by an engine control device (not shown). The high rotation state is a state in which the engine 21 is driven at a rotation speed in the vicinity of the rotation speed from the rated rotation speed to the rotation speed at high idle (maximum fuel supply amount is set and no load is applied). It is. The low rotation state is a state in which the engine 21 is driven at a rotation speed near the rotation speed at the time of low idle (the minimum rotation speed at which the engine 21 can be stably driven). Here, the rotation speed (per unit time) of the engine 21 in the high rotation state is referred to as a first rotation speed, and the rotation speed of the engine 21 in the low rotation state is referred to as a second rotation speed.

The generator 22 generates power by driving the engine 21. In this embodiment, the case where the generator 22 is a three-phase AC synchronous generator will be described as an example, but the type of the generator 22 may be any type. The generator 22 is connected to the control box 24, and the three-phase AC electrical output from the generator 22 is input to the control box 24.

Further, in the present embodiment, the generator 22 has a power generation characteristic of a first mode adapted when the engine 21 is in a high rotation state and a second mode adapted when the engine 21 is in a low rotation state. Can generate power in two different modes. A specific configuration for the generator 22 to switch between the two modes will be described later (see FIG. 4). In addition, switching between the two modes is performed based on a command from the control box 24.

The operation panel 23 is an input means for a user (operator), and on / off of driving of each control target device (actuators 5 to 7 and heating device 12) and a driving state of each control target device (for example, the conveyor 6). And the like, and the like, and the like. In the present embodiment, the operation panel 23 can input at least the next operation instruction.
Switching instruction: An instruction to switch between a high rotation state and a low rotation state of the engine.
Individual start instruction: an instruction to start each actuator individually. Heating instruction: an instruction to start heating by the heating device 12.
Multiple activation instruction: An instruction to activate a plurality of control target devices at once. It is provided for the purpose of reducing the effort of the user (operator) operation.
Change instruction: An instruction to change the driving state of each control target device.
The operation panel 23 is connected to the control box 24, and a signal representing an operation instruction input to the operation panel 23 is input to the control box 24.

The control box 24 is connected to the motors 30 to 32b and the heating device 12, and controls the operations of the motors 30 to 32b and the heating device 12. As shown in FIG. 2, the control box 24 includes a controller 25, a traveling inverter (in FIG. 2, the inverter (AC Drive) is abbreviated as “AC-D”, the same shall apply hereinafter) 26, a right conveyor inverter 27a, It has a left conveyor inverter 27 b, a right screw inverter 28 a, a left screw inverter 28 b, and a power regulator 29.

The controller 25 is connected to the operation panel 23, the inverters 26 to 28b, and the power regulator 29. The controller 25 controls each of the inverters 26 to 28b and the power regulator 29 based on an operation instruction from the operation panel 23 or the like. The controller 25 is connected to the generator 22 and outputs a mode switching instruction to the generator 22. The controller 25 is typically a sequencer including information processing means such as a CPU and storage means such as a memory, and operates according to a program. However, the controller 25 may be realized by a dedicated circuit using a relay circuit or the like.

The inverters 26 to 28b are connected to the generator 22, and drive the motors 30 to 32b by converting the three-phase AC power supplied from the generator 22 into a desired frequency and outputting the same. The frequency (or power) of AC electricity output from each of the inverters 26 to 28b is adjusted according to the control instruction of the controller 25. That is, each of the inverters 26 to 28b drives each of the motors 30 to 32b in accordance with a control instruction from the controller 25.

Specifically, the traveling inverter 26 is connected to the traveling motor 30 and drives the traveling motor 30. The traveling motor 30 drives the right rear wheel 5 a and the rear wheel 5 b via the differential gear 33.

Also, the right conveyor inverter 27a is connected to the right conveyor motor 31a and drives the right conveyor motor 31a. The right conveyor motor 31 a drives the right conveyor 6 a of the conveyors 6. Similarly, the left conveyor inverter 27b is connected to the left conveyor motor 31b and drives the left conveyor motor 31b. The left conveyor motor 31 b drives the left conveyor 6 b of the conveyor 6.

The right screw inverter 28a is connected to the right screw motor 32a and drives the right screw motor 32a. The right screw motor 32 a drives the right screw 7 a of the screws 7. Similarly, the left screw inverter 28b is connected to the left screw motor 32b and drives the left screw motor 32b. The left screw motor 32 b drives the left screw 7 b of the screws 7.

FIG. 3 is a diagram for explaining the difference in current when the motor is started when the inverter is used and when it is not used. The vertical axis of the graph shown in FIG. 3 represents the ratio of the current that actually flows relative to the rated current, and the horizontal axis represents time. As shown in FIG. 3, when the inverter is not used, an inrush current of about 5 times the rated current is generated at the time of motor start-up (a period during acceleration until the inverter output frequency and the motor rotation speed match). Flowing. On the other hand, when an inverter is used, the current at startup can be suppressed to about twice the rated current by control by a switching element or the like in the inverter.

The power regulator 29 is connected to the generator 22 and controls the operation of the heating device 12 by adjusting and outputting the three-phase AC power supplied from the generator 22. The power regulator 29 can continuously change the power supplied to the heating device 12 between 0% and 100% of the maximum output. Here, the power (frequency) of AC electricity output from the power regulator 29 is adjusted according to the control instruction of the controller 25. That is, the power regulator 29 controls the operation of the heating device 12 according to the control instruction of the controller 25. The heating device 12 generates heat by the power supply from the power regulator 29, and the screed 11 (screed plate) is heated.

Next, the detailed configuration of the generator 22 will be described. FIG. 4 is a diagram showing the internal electrical wiring of the generator shown in FIG. As shown in FIG. 4, the generator 22 includes a three-phase coil 41 and first to third switches 42a to 42c. One ends of the three coils constituting the three-phase coil 41 are connected to each other (Y-connected), and three-phase lines extending from the other end (output end) are controlled via the first switch 42a. Each is connected to a box 24. The first switch 42 a connects / disconnects between the output ends of the three coils and the control box 24. The output ends of the three coils are connected to each other via the second switch 42b between the output end and the first switch 42a. The second switch 42b connects / disconnects the output ends of the three coils. The central portions of the three coils are connected to the control box 24 via the third switch 42c. The third switch 42c connects / disconnects between the central portion of the three coils and the control box 24. Each of the switches 42a to 42c is connected to the controller 25 and switches connection / disconnection in accordance with a switching instruction from the controller 25. Although details will be described later, with the configuration shown in FIG. 4, the generator 22 can change the number of turns of the three-phase coil 41 by switching the switches 42a to 42c, and the first mode and the second mode described above can be changed. The mode can be switched.

In addition, the internal wiring of the generator 22 shown in FIG. 4 is an example, and in other embodiments, the generator 22 has any configuration as long as the number of turns of the three-phase coil can be changed. There may be. In the present embodiment, the power generation characteristics of the generator 22 are switched by changing the number of turns of the coil of the generator 22, but the method of switching the power generation characteristics is not limited to this. For example, the power generation characteristics can be switched by changing the number of coils or changing the number of magnets and magnetic flux of the generator (when using an electromagnet). In view of downsizing the configuration of the generator, it is preferable to switch the power generation characteristics by switching the electrical wiring as in the present embodiment.

(Operation of asphalt finisher)
Next, the operation of the asphalt finisher according to the present embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing the flow of processing in the controller 25 shown in FIG. In the present embodiment, the controller 25 performs the operation shown in FIG. 5 by executing a predetermined program. In other embodiments, the controller 25 is realized by a dedicated circuit that executes the process shown in FIG. May be. The controller 25 repeatedly executes a series of processes in steps S1 to S11 shown in FIG. 5 while the asphalt finisher is operating (while the engine 21 is being driven).

First, in step S1, the controller 25 determines whether or not the rotation speed (high rotation state / low rotation state) of the engine 21 has been switched. In the present embodiment, the determination in step S 1 is made based on whether or not the above-described switching instruction (instruction to switch the engine 21 between the high rotation state and the low rotation state) has been performed by the user. Specifically, the controller 25 inputs an operation instruction signal from the operation panel 23 and determines whether or not a switching instruction has been performed. For example, the operation panel 23 is provided with a switching lever, and a switching instruction is performed using this switching lever. If the determination result of step S1 is affirmative, the process of step S2 is executed. On the other hand, if the determination result of step S1 is negative, the process of step S2 is skipped and the process of step S3 is executed.

Here, when a switching instruction is given to the operation panel 23, an engine control device (not shown) switches between a high rotation state and a low rotation state of the engine 21. That is, when the switching lever is switched to the side representing the high rotation state, the engine control device controls the engine 21 so as to achieve the first rotation speed. Further, when the switching lever is switched to the side representing the low rotation state, the engine control device controls the engine 21 so as to be the second rotation speed (slower than the first rotation speed). . Therefore, it can be said that the process of step S1 for determining whether or not a switching instruction is performed is a process for detecting whether the engine 21 is in a high rotation state or a low rotation state. In other embodiments, switching between the high rotation state and the low rotation state of the engine 21 is performed according to a predetermined condition (for example, when the total power consumption of each control target device exceeds a predetermined value). It may be done automatically.

In step S1, in order to detect whether the engine 21 is in a high rotation state or a low rotation state, the controller 25 determines whether or not the switching instruction has been performed. Here, in another embodiment, the method for detecting whether the engine 21 is in a high rotation state or a low rotation state may be another method. For example, in another embodiment, the controller 25 detects the rotation speed of the engine 21 or the generator 22 and determines whether the engine 21 is in a high rotation state or a low rotation state based on the detected rotation speed. May be.

In step S2, the controller 25 switches the mode of the generator 22. That is, the controller 25 controls the switches 42 a to 42 c in the generator 22 to change the number of turns of the three-phase coil 41. Specifically, when the engine 21 is switched to a high rotation state, the first switch 42a is disconnected, the second switch 42b is connected, and the third switch 42c is connected. Accordingly, in the three-phase coil 41, three coils are divided at the center, and the two divided coils are connected in parallel. That is, the number of turns of the three-phase coil 41 is substantially halved. On the other hand, when the engine 21 is switched to the low rotation state, the first switch 42a is connected, the second switch 42b is disconnected, and the third switch 42c is disconnected. In this case, since the two coils divided in the high rotation state are connected in series, the number of turns of the three-phase coil 41 is doubled (compared to the low rotation state). In the present embodiment, the number of turns of the coil is halved in the high rotation state, but the amount of change in the number of turns of the coil between the high rotation state and the low rotation state is not limited to this. The number of turns in each state of the high rotation state and the low rotation state is appropriately set in consideration of the rotation speed of the engine 21 in each state, the amount of electric power assumed to be necessary in each state, and the like.

As described above, in the present embodiment, the generator 22 changes the number of turns of the three-phase coil 41 in two modes. In the low rotation state, the second mode in which the number of turns of the three-phase coil 41 is relatively large is set so that the engine 21 can cope with the low speed rotation (second rotation speed). That is, by increasing the number of turns, the number of revolutions of the generator 22 for obtaining a desired output power can be reduced, and power generation can be started at a low number of revolutions. Further, when the engine 21 is in a low rotation state, the power output in the second mode is larger than the power output in the first mode in the same case.

On the other hand, in the high rotation state, by setting the first mode in which the number of turns of the three-phase coil 41 is relatively small, it is possible to cope with the high speed rotation (first rotation number) of the engine 21. That is, by reducing the number of turns, the output power during high-speed rotation can be increased as compared with the second mode.

Thus, in the present embodiment, it is possible to efficiently generate power by switching the mode of the generator 22 so that the power generation characteristics corresponding to the two types of rotation speeds of the engine 21 are obtained.

In the present embodiment, it is detected whether the engine 21 is in a high rotation state or a low rotation state, and the mode of the generator 22 is automatically switched according to the detection result. As a result, the generator 22 can be driven in an optimal mode that matches the rotational speed of the engine 21 without the user manually operating the mode of the generator 22. However, in other embodiments, the user may be able to manually operate the mode of the generator 22 (independent of the switching instruction for the engine 21).

Here, it is necessary to keep the screed plate at 100 ° C. or higher at the start of pavement construction. Therefore, when the asphalt finisher 1 is actually used, it is conceivable that the screed 11 is heated in advance by driving the heating device 12 in the preparation stage for pavement construction. Therefore, it is preferable that the engine 21 be in a low rotation state in the preparatory stage for pavement construction, and the heating device 12 can operate even in a low rotation state. Therefore, in the present embodiment, the output power in the second mode in the low rotation state is designed to be larger than the power required for the operation of the heating device 12. That is, the power generation characteristics in the second mode of the generator 22 are set so that the heating device 12 can be operated at least in the low rotation state. Furthermore, in this embodiment, the power generation characteristics in the second mode of the generator 22 are such that, in addition to the heating device 12 in the low rotation state, other actuators are operated with low power (compared to the high rotation state). Is set to be able to.

After step S2, the process of step S3 is executed. In step S3, the controller 25 determines whether any one of the actuators is activated individually. The determination in step S3 is performed depending on whether the above-described individual activation instruction (instruction for individually activating each actuator) has been performed by the user. Specifically, the controller 25 inputs an operation instruction signal from the operation panel 23 and determines whether or not the individual activation instruction has been performed. In the present embodiment, the operation panel 23 is provided with a switch for activating an actuator for each actuator, and the individual activation instruction is an instruction for one of the switches. If the determination result of step S3 is affirmative, the process of step S4 is executed. On the other hand, if the determination result of step S3 is negative, the process of step S4 is skipped and the process of step S5 is executed.

In step S4, an individual activation process for activating one of the actuators is executed. In the individual activation process, the motors 30 to 32b and the heating device 12 are controlled such that their total power consumption does not exceed the power generation amount of the generator 22. Hereinafter, the details of the individual activation process will be described with reference to FIG.

FIG. 6 is a sub-flowchart showing detailed processing of step S4 shown in FIG. In the individual activation process shown in FIG. 6, first, in step S 21, the controller 25 determines whether or not the heating by the heating device 12 is being performed. If the determination result of step S21 is affirmative, the process of step S22 is executed. On the other hand, when the determination result of step S21 is negative, the process of step S22 is skipped and the process of step S23 is executed.

In step S22, the controller 25 stops heating in the heating device 12. Specifically, a control instruction for stopping power supply to the heating device 12 is given to the power regulator 29. Thereby, the power regulator 29 stops the output of the electric power to the heating apparatus 12, and the heating by the heating apparatus 12 is stopped. Although details will be described later, the stop of the heating in step S22 is a temporary stop, and when the heating is stopped in step S22, the heating is resumed in step S27 described later. After step S22, the process of step S23 is executed.

In step S23, the controller 25 determines whether or not the generator 22 is in the first mode. If the determination result of step S23 is affirmative, the process of step S24 is executed. On the other hand, when the determination result of step S23 is negative, the process of step S25 is executed.

In step S24, the controller 25 starts activation of the actuator related to the individual activation instruction (sometimes referred to as “normal activation” in the sense of being distinguished from activation in step S25). That is, the controller 25 instructs the inverter corresponding to the actuator related to the individual activation instruction to start power supply to the actuator. As a result, the inverter starts power output to each motor, and driving of the actuator is started by the motor. After step S24, the process of step S26 is executed.

On the other hand, in step S25, the controller 25 starts activation of the actuator according to the individual activation instruction with lower power than the normal activation in step S24. That is, the controller 25 instructs the inverter corresponding to the actuator related to the individual activation instruction to start power supply to the actuator with lower power than the normal activation. As a result, the inverter starts power output to the motor with lower power than normal startup, and driving of the actuator is started by the motor. Therefore, in step S25, the actuator is driven at a lower output (lower speed) than in the case of normal activation. After step S25, the process of step S26 is executed.

As described above, in the present embodiment, when the engine 21 is in the low rotation state and the generator 22 is in the second mode, the process of step S25 is executed, and the power is lower than in the case of normal startup (step S24). The actuator is activated. That is, in the low rotation state, the actuator is activated with lower power than in the high rotation state. Here, since the output power of the generator 22 in the low rotation state is smaller than that in the high rotation state, if the actuator is started in the same manner as in the high rotation state, the actuator can be driven without the power of the generator 22 being sufficient. There is a possibility of disappearing. On the other hand, by the process of step S25, each actuator can be driven more reliably (although it has a low output) even in a low rotation state.

In other embodiments, each actuator may not be activated in a low rotation state. That is, when the determination result of step S23 is negative, the controller 25 may skip the process of step S25 and execute the process of step S26 described later. In other embodiments, only specific actuators (for example, the conveyor 6 and the screw 7) are activated at low power according to the process of step S25, and other actuators are not activated (or normally activated). Also good.

In step S26, the controller 25 determines whether or not the activation of the actuator started in step S24 or S25 is completed. Here, “actuator activation is completed” means that the power consumption has settled below a predetermined value after the actuator is activated. In the present embodiment, the determination in step S26 is performed based on whether or not the elapsed time since the start of the actuator has exceeded a predetermined time. The predetermined time is set in advance, and may be set for each actuator, or the same time may be set for each actuator. In other embodiments, the determination in step S26 may be performed based on whether or not the power required for driving the actuator is equal to or less than a predetermined value. If it is determined in step S26 that the actuator has been activated (elapsed time has exceeded a predetermined time), the process of step S27 is executed. On the other hand, when it is determined in step S26 that the actuator has not been started, the process of step S26 is executed again. That is, the controller 25 waits for the process while the actuator is activated, and starts the process of step S27 when the activation of the actuator is completed.

In step S27, the controller 25 restarts heating by the heating device 12. Specifically, a control instruction to start power supply to the heating device 12 is given to the power regulator 29. As a result, the power regulator 29 starts outputting power to the heating device 12 and heating by the heating device 12 is started. In addition, when the heating by the heating device 12 is not stopped in the above-described step S22 (the heating device 12 is not originally operating), the process of step S27 is not executed. After step S27, the controller 25 ends the individual activation process.

According to the individual activation process described above, the controller 25 waits until the activation of a certain actuator is completed (step S26), so that no other actuator is activated while the actuator is activated. Here, since the power consumption temporarily increases when the motor is started, if a plurality of actuators are simultaneously started, the total power consumption for driving the actuators may exceed the power generated by the generator 22. (See FIG. 9). In this case, it is conceivable that an overload is applied to the generator 22, leading to problems such as engine stop. On the other hand, according to this embodiment, since a plurality of actuators are not activated simultaneously, the total power consumption does not exceed the generated power of the generator 22, and each actuator can be driven reliably. . Further, according to the individual activation process, the controller 25 temporarily stops the heating of the heating device 12 while activating an actuator (step S22). It can prevent exceeding electric power.

Returning to the description of FIG. 5, in step S 5, it is determined whether or not a plurality of predetermined control target devices are activated at a time. The determination in step S5 is performed based on whether the above-described multiple activation instruction (instruction for activating a plurality of control target devices at once) has been performed by the user. Specifically, the controller 25 inputs an operation instruction signal from the operation panel 23 and determines whether or not the multiple activation instruction has been performed. In the present embodiment, the operation panel 23 is provided with a switch for activating a predetermined plurality of control target devices at once, and the multiple activation instruction is an instruction for this switch. If the determination result of step S5 is affirmative, the process of step S6 is executed. On the other hand, when the determination result of step S5 is negative, the process of step S6 is skipped and the process of step S7 is executed.

In step S6, a plurality of activation processes for activating a plurality of predetermined control target devices at once are executed. Also in the multiple activation process, as in the individual activation process, each of the motors 30 to 32b and the heating device 12 has the total power consumption of the power generation amount (in the first mode) when the engine 21 is in a high rotation state. It is controlled not to exceed. Details of the multiple activation process will be described below with reference to FIG. In the following, a case where three of the conveyor 6, the screw 7, and the heating device 12 are activated at a time as the “predetermined plural control target devices” will be described as an example.

FIG. 7 is a sub-flowchart showing detailed processing of step S6 shown in FIG. In the multiple activation process shown in FIG. 7, first, in step S30, the controller 25 determines whether or not the generator 22 is in the first mode. If the determination result of step S30 is affirmative, the process of step S31 is executed. On the other hand, when the determination result of step S30 is negative, the controller 25 ends the multiple activation process.

In step S31, the controller 25 designates the predetermined plurality of control target devices in order (one by one). Here, it is assumed that the controller 25 designates the conveyor 6, the screw 7, and the heating device 12 one by one every time step S 31 arrives. The order of designation may be any order, but it is preferable to designate the heating apparatus 12 last (when one or more actuators and the heating apparatus are activated simultaneously). The power consumption when starting the heating device 12 is (a) (unlike starting the motor) that the power consumption is not temporarily increased at the time of starting, and (b) the response of the heating device 12 is the motor In view of the fact that there is no significant difference in the start timing of the heating device 12, it is less necessary to start the heating device 12 first. Following step S31, the process of step S32 is executed.

In step S32, the controller 25 activates the control target device specified in step S31. Specific processing in step S32 is the same as that in step S24 or S27 described above. In step S32, if the control target device specified in step S31 is already driven (that is, if the control target device has already been started when a plurality of start instructions are issued), step S32 is executed. This process is not executed. Following step S32, the process of step S33 is executed.

In step S33, the controller 25 determines whether or not the activation of the control target device started in step S32 is completed. The process in step S33 is the same as that in step S26 described above. Note that the heating device 12 does not drive a motor, so power consumption does not increase temporarily immediately after startup (see graph G shown in FIG. 9). Therefore, when the device to be controlled is the heating device 12, the predetermined time in step S26 may be set to “0”. If it is determined in step S33 that the activation of the control target device has ended, the process of step S34 is executed. On the other hand, if it is determined in step S33 that the control target device has not been activated, the process of step S33 is executed again. That is, the controller 25 waits for the process while the control target device is activated, and executes the process of step S34 when the control target device is activated.

In step S34, the controller 25 determines whether or not all of the predetermined plurality of control target devices have been activated. If the determination result of step S34 is negative, the process of step S31 is executed again. On the other hand, when the determination result of step S34 is affirmative, the controller 25 ends the multiple activation process.

In the multiple activation process, when the generator 22 is in the second mode (when the engine 21 is in a low rotation state), the control target device is not activated and the multiple activation instruction is not accepted. It becomes. This is because the necessity of activating a plurality of control target devices in a low rotation state is considered low. However, in other embodiments, when the generator 22 is in the second mode, each control target device is activated with lower power (than in the case of the first mode) as in step S25 described above. You may make it do.

As described above, according to the above-described multiple activation process, the user can activate a plurality of control target devices at once by a multiple activation instruction. As a result, it is possible to save the user's operation and simplify the operation. Further, according to the multiple activation process, the controller 25 activates each of the plurality of control target devices while shifting the activation start timing. As a result, the total power consumption of each control target device can be prevented from exceeding the maximum power generation amount of the generator 22 in the high rotation state.

FIG. 9 is a diagram showing power consumption when a plurality of control target devices are activated. In FIG. 9, the vertical axis of each graph A to H represents power consumption, and the horizontal axis represents time. The left graphs A to D show a case where a plurality of control target devices are started simultaneously, and the right graphs E to H show a case where a plurality of control target devices are started at different timings. Here, if a plurality of devices to be controlled are simultaneously activated as shown in graphs A to C in FIG. 9, the total power consumption at the time of activation is determined as the generator as shown in the graph D in FIG. There is a risk of exceeding the generated power of 22. On the other hand, in the above-described multiple activation processing, as shown in graphs E to G shown in FIG. As a result, as shown in the graph H shown in FIG. 9, it is possible to prevent the total power consumption at startup from exceeding the power generated by the generator 22. As described above, in this embodiment, the controller 25 controls the motors and the heating devices so that the total power consumption of the motors and the heating devices does not exceed the power generation amount generated by the first mode in the high rotation state. Control the behavior.

The control method for preventing the total power consumption from exceeding the power generation amount of the generator 22 is not limited to the above. For example, in another embodiment, the controller 25 drives each control target device so that the power at the time of startup is lower than that of the individual startup processing and gradually increases the power in the multiple startup processing. You may make it start each control object apparatus simultaneously. This also makes it possible to control so that the total power consumption does not exceed the power generation amount of the generator 22.

Returning to the description of FIG. 5, in step S 7, the controller 25 determines whether or not heating by the heating device 12 is started. The determination in step S7 is performed depending on whether the above-described heating instruction (instruction to start heating by the heating device 12) has been performed by the user. Specifically, the controller 25 receives an input of an operation instruction signal from the operation panel 23 and determines whether or not the heating instruction has been performed. In the present embodiment, the operation panel 23 is provided with a switch for operating the heating device 12, and the heating instruction is an instruction to this switch. If the determination result of step S7 is affirmative, the process of step S8 is executed. On the other hand, if the determination result of step S7 is negative, the process of step S8 is skipped and the process of step S9 is executed.

In step S8, the controller 25 operates the heating device 12. The process of step S8 is the same as the process of step S27 described above. Following step S8, the process of step S9 is executed.

In step S9, it is determined whether or not to change the drive state of each control target device. The determination in step S9 is performed based on whether or not the above change instruction (instruction to change the driving state of each control target device) has been performed by the user. Specifically, the controller 25 receives an input of an operation instruction signal from the operation panel 23 and determines whether or not the change instruction has been performed. In the present embodiment, the operation panel 23 is provided with a dial for designating the driving state of each control target device (for example, the conveyance speed for the conveyor 6 and the heating temperature for the heating device 12). The change instruction is an instruction to this dial. Note that the change instruction includes an instruction to stop driving the control target device, and the change instruction may be an instruction to turn off a switch for starting the actuator (see step S3 above). If the determination result of step S9 is affirmative, the process of step S10 is executed. On the other hand, if the determination result of step S9 is negative, the process of step S10 is skipped and the process of step S1 is executed again. Thereafter, the processes of steps S1 to S10 are repeatedly executed.

In step S10, the controller 25 controls the device to be controlled according to the change instruction. Specifically, the controller 25 controls the output frequency so that the inverter (or the power regulator 29) corresponding to the control target device related to the change instruction is in the drive state specified by the change instruction. Give instructions. In addition, when the change instruction is an instruction to stop driving of the control target device, a control instruction to stop power feeding is performed. As a result, the device to be controlled is controlled according to the change instruction. After step S10, the process of step S11 is executed.

In step S11, power adjustment processing is executed. The individual activation process and the multiple activation process are processes for controlling the total power consumption so as not to exceed the generated power of the generator 22 when the control target device is activated. In addition, this is a process for controlling the total power consumption so as not to exceed the generated power of the generator 22 during the driving of a plurality of control target devices. Hereinafter, the details of the individual activation process will be described with reference to FIG.

FIG. 8 is a sub-flowchart showing detailed processing of step S11 shown in FIG. In the power adjustment process shown in FIG. 8, first, in step S41, the controller 25 calculates the total power consumption of each control target device. That is, the controller 25 detects the power consumption of each control target device and adds the detected power consumption. The detection method of each power consumption may be any method, for example, the power supplied to each motor 30 to 32b may be detected. Following step S41, the process of step S42 is executed.

In step S42, the controller 25 determines whether or not the total power consumption is equal to or greater than a predetermined value. This predetermined value is set in advance to the maximum power of the generator 22 or a value slightly lower than the maximum power. When the determination result of step S42 is affirmative, the process of step S43 is executed. On the other hand, when the determination result of step S42 is negative, the process of step S43 is skipped, and the controller 25 ends the power adjustment process.

In step S43, the controller 25 adjusts the power supplied to the device to be controlled so that the total power consumption is smaller than the predetermined value. Although the specific method of adjustment in step S43 may be any method, for example, the following method can be considered. That is, the controller 25 selects one or a plurality of control target devices that are currently being driven, and restricts (stops or reduces) power supply to the selected control target devices. In addition, as a method of selecting the control target device that restricts power supply, for example, first, the heating device 12 is selected, and when the heating device 12 is stopped, the conveyor 6 and / or the screw 7 may be selected. It is done. In addition, the controller 25 may reduce the power supplied to each control target device currently driven. After the step S43, the controller 25 ends the power adjustment process.

According to the above step S43, it is possible to control so that the total power consumption of the device to be controlled does not exceed the power generated by the generator 22. Further, since the process of step S43 is always (repeatedly) performed during the operation of the asphalt finisher, it is possible to always prevent the total power consumption from exceeding the generated power of the generator 22 during the operation of the asphalt finisher. .

In the present embodiment, as a process for controlling the total power consumption of the control target device so as not to exceed the generated power of the generator 22, the controller 25 performs three types of processes of step S4, step S6, and step S11. Was executed. Here, in other embodiments, the controller 25 may execute only one or two of these three types of processes.

After the power adjustment process in step S11, the process in step S1 is executed again. Thereafter, the processes of steps S1 to S11 are repeatedly executed. Above, description of operation | movement of the controller 25 shown in FIG. 5 is complete | finished.

In addition, regarding the driving of the heating device 12, in addition to the processing shown in FIGS. 5 to 7, control based on the heating temperature may be performed. That is, the asphalt finisher 1 may further include a temperature detection unit that detects the temperature of the screed plate, and the drive of the heating device 12 may be controlled based on the detection result of the temperature detection unit. Specifically, when the temperature detected by the temperature detection means reaches a predetermined target temperature (between the time when the user gives a heating instruction and the time when the change instruction to stop heating is given), the controller 25 If the driving of the heating device 12 is stopped and the detected temperature falls below a predetermined target temperature, the heating device 12 may be driven. In this case, the determination in step S21 may be performed in the same manner as described above. On the other hand, if the heating instruction by the user has already been performed, the process of step S32 is performed so as not to drive the heating device 12 (even if the detected temperature has not reached the target temperature). Good.

As described above, according to the above embodiment, the asphalt finisher 1 can electrically drive the main actuator and screed heating. As a result, energy can be saved and the amount of carbon dioxide emission can be reduced as compared with the case of driving with a hydraulic system. In addition, since it is not necessary to perform maintenance on the hydraulic system, it is possible to reduce maintenance costs and facilitate maintenance. Furthermore, by performing electrical control on each control target device (especially when an inverter is used as in the above embodiment), the controllability for each control target device can be improved.

In addition, according to the above-described embodiment, the conventional method can be improved in terms of heat uniformity, combustion efficiency, and safety of the screed plate by electrically driving the heating of the screed 11. That is, in the conventional method in which the screed plate is heated with gas, the screed plate has a long and thin shape, and thus it has been difficult to uniformly heat the screed plate with a gas burner. Further, since the gas burner employs a downward combustion structure (because it is necessary to heat the screed plate from above), the combustion gas flows upward, resulting in poor combustion efficiency. On the other hand, according to the said embodiment, the soaking | uniform-heating property and combustion efficiency of a screed plate can be improved by electrically heating a screed plate with an electric heater. Furthermore, in the conventional method, there is a problem that a fire risk is caused by mounting a gas cylinder or arranging the hydraulic piping of the hydraulic system in the vicinity of the gas burner. On the other hand, according to the said embodiment, since it is the structure which does not use gas, there is no conventional fire risk and safety can be improved.

Further, according to the above embodiment, the engine 21 can be driven at two types of rotation speeds (low rotation state and high rotation state), and the generator 22 can switch the power generation characteristics according to the rotation speed of the engine 21. Is possible. Thus, noise can be reduced by enabling driving in a low rotation state. Further, since the generator 22 generates power with characteristics adapted to the low rotation state, it is possible to improve the power generation efficiency and further save energy. Furthermore, according to the above-described embodiment, the power to perform screed heating is ensured even in a low rotation state, so that the asphalt finisher 1 can be set in a low rotation state when preparing for paving work even in consideration of actual use. it can. Therefore, it is possible to reduce noise and exhaust carbon dioxide during preparation.

Further, according to the above embodiment, the generator 22 can adjust the voltage input to each inverter to an appropriate magnitude by switching the power generation characteristics. In the above embodiment, the first to third switches 42a to 42c correspond to the adjusting unit described in the claims. In the case of a normal generator, the output voltage varies greatly between when the engine 21 is in a low rotation state and when it is in a high rotation state. In either case, the output voltage satisfies the input allowable voltage of the inverter. There is a risk of disappearing. On the other hand, according to the above embodiment, the generator 22 switches the two modes so that the output voltage is the same both when the engine 21 is in the low rotation state and in the high rotation state. It can be a value of the degree. That is, in any case, since the output voltage of the generator 22 satisfies the input allowable voltage of the inverter, a voltage having an appropriate magnitude is input to the inverter.

(Modification)
The said embodiment is one form for implementing this invention, and this invention can also be implemented as a modified example demonstrated below, for example.

(Variation that electrically drives the vibrator)
Although the case where the main actuator is electrically driven has been described as an example in the above embodiment, other actuators other than the main actuator may be electrically driven. For example, the asphalt finisher may electrically drive the vibrator 13 in addition to the main actuator. Hereinafter, an example in which the vibrator 13 is electrically driven will be described as a first modification.

FIG. 10 is a diagram showing an electrical configuration of the asphalt finisher according to the first modification. In FIG. 10, portions different from those in FIG. 2 are mainly shown, and description of the same configuration as that in FIG. 2 is omitted. In the first modification, the asphalt finisher includes a right main vibrator motor 52a, a left main vibrator motor 52b, a right telescopic vibrator motor 52c, and a left telescopic vibrator motor 52d in addition to the configuration shown in FIG. I have. Further, the control box 24 includes a vibrator inverter 51 in addition to the configuration shown in FIG.

In FIG. 10, the vibrator inverter 51 is connected to the generator 22, and converts the three-phase AC power supplied from the generator 22 into a desired frequency (after being once rectified to DC) and outputs it, Each motor 52a to 52d is driven. The frequency of AC electricity output from the vibrator inverter 51 is adjusted according to the control instruction of the controller 25. That is, the vibrator inverter 51 drives each of the motors 52a to 52d in accordance with a control instruction from the controller 25.

The right main vibrator motor 52 a drives the right main vibrator 13 a that vibrates the right main screed of the screed 11. The left main vibrator motor 52 b drives the left main vibrator 13 b that vibrates the left main screed of the screed 11. The right extension vibrator motor 52 c drives the right extension vibrator 13 c that vibrates the right extension screed of the screed 11. The left telescopic vibrator motor 52 d drives the left telescopic vibrator 13 d that vibrates the left telescoping screed of the screed 11.

Control of the vibrator 13 (vibrators 13a to 13d) when the asphalt finisher is used is the same as that of each actuator in the above embodiment. That is, the vibrator 13 may be activated in accordance with an individual activation instruction or a plurality of activation instructions by the user, or the driving state may be changed or stopped according to a change instruction by the user.

As described above, by electrically driving the vibrator 13, energy efficiency can be further improved compared to the case of hydraulic driving. Further, by electrically controlling the vibrator 13, the vibration frequencies of the vibrators 13a to 13d can be controlled with higher accuracy, and the vibrators 13a to 13d can be operated at the same frequency. Furthermore, since the hydraulic piping to the vibrator 13 is not required, the expansion / contraction mechanism of the screed 11 can be simplified.

It should be noted that any actuator that is not particularly described in the above embodiment and the first modification (the telescopic mechanism of the screed 11 and the driving mechanism of the leveling arm 8) may be driven by any hydraulic drive. Or may be electrically driven.

(Modification that enables external power supply)
In the above-described embodiment, each control target device is electrically driven by electric power from the generator 22 using the engine 21 as a drive source. Here, the asphalt finisher can receive power supply from an external power source, and each control target device may be driven by power from the external power source. Hereinafter, an example in which each control target device is driven by power from an external power source will be described as a second modification.

FIG. 11 is a diagram showing an electrical configuration of the asphalt finisher according to the second modification. Note that FIG. 11 mainly shows parts different from FIG. 2, and a part of the same configuration as FIG. 2 is omitted. In the second modification, the asphalt finisher includes a power plug 61 and a changeover switch 62 in addition to the configuration shown in FIG. 2 (or FIG. 10).

A power plug 61, which is an example of a power supply terminal for obtaining external power, is detachably connected to the external power supply and receives power supply from the external power supply. The changeover switch 62 is provided between the generator 22 and the control box 24 and between the power plug 61 and the control box 24, and connects either the generator 22 or the power plug 61 and the control box 24. To do. With the above configuration, the control box 24 can switch between the power from the generator 22 and the power from the power plug 61. Although not shown, the changeover switch 62 is connected to the controller 25, and the changeover of the changeover switch 62 may be performed in accordance with a change instruction from the controller 25. The controller 25 may switch the changeover switch 62 in accordance with a user's instruction, and when it is provided with detection means for detecting that the power plug 61 is connected to an external power source, if this is detected. Switching may be performed so that the power plug 61 and the control box 24 are automatically connected.

As described above, in the second modified example, the asphalt finisher is configured to be able to receive power supply from an external power source. Thus, for example, at the time of preparation for pavement construction, the heating device 12 can be driven by power supplied from an external power source, and the engine 21 can be stopped. Therefore, according to the second modification, it is possible to further save energy and to further reduce carbon dioxide emissions.

(Modification to adjust the output of the generator)
In the above embodiment, the generator output in the two states is adjusted by changing the power generation characteristics (specifically, the number of turns of the coil) of the generator between the high rotation state and the low rotation state. As a result, the voltage input to each inverter is approximately the same in the two states, so that a voltage within a predetermined allowable input voltage range of each inverter can be input. Here, in other embodiments, the adjustment of the output voltage of the generator in the above two states may be realized by the configuration of each modification shown below. Hereinafter, modified examples for adjusting the output of the generator will be described as third to seventh modified examples.

(Third Modification)
FIG. 12 is a diagram illustrating an electrical configuration of an asphalt finisher according to a third modification. Note that FIG. 12 mainly shows portions that are different from FIG. 2, and a description of the same configuration as FIG. 2 is omitted. In the third modification, the asphalt finisher includes a rectifier 71 and a constant voltage device 72 in addition to the configuration shown in FIG. In the third modification, the asphalt finisher includes a generator 70 instead of the above-described generator 22. Although only a part is shown in FIG. 12, the asphalt finisher includes the inverters 26 to 28b as in the above embodiment. Although not shown in FIG. 12, the controller 25 is connected to each of the inverters 26 to 28b and the power regulator 29, and the inverters 26 to 28b and the power regulator 29 are controlled by the controller 25, as in the above embodiment. Is done.

The generator 70 is mechanically connected to the engine 21 and generates power by driving the engine 21. In the third modified example, the generator 70 is not limited to the generator having the two generation characteristics like the generator 22 in the above-described embodiment, and may be any type of generator, for example, conventional power generation It may be a machine. Therefore, in the third modified example, it is possible to use a small and high-efficiency motor using a permanent magnet such as an IPM motor, for example, so that power generation is performed as compared with the above-described embodiment and a fourth modified example described later. The efficiency can be improved and the apparatus can be miniaturized.

The rectifier 71 is connected to the generator 70 and converts (rectifies) AC electricity (here, three-phase AC electricity) output from the generator 70 into DC electricity. Any type of rectifier 71 may be used as long as it has a function of converting AC electricity into DC.

The constant voltage device 72 is connected to the rectifier 71 and adjusts (boosts or steps down) the voltage of DC electricity output from the rectifier 71 to a voltage within a predetermined range. That is, in the third modified example, the constant voltage device 72 corresponds to the adjusting unit described in the claims. Here, the predetermined range is a range of allowable input voltage of each of the inverters 26 to 28b. The constant voltage device 72 may have any configuration as long as it has a function of adjusting the voltage of DC electricity, such as a configuration including a general booster circuit. The constant voltage device 72 preferably has a function of stepping up and stepping down the input voltage, but it is sufficient that it has at least a function of stepping up the input voltage. For example, when it is not assumed that a voltage higher than the predetermined range is input (that is, when the output voltage of the generator 70 is not expected to exceed the predetermined range), the constant voltage device 72 has a step-down function. May not be included.

The inverters 26 to 28b are connected to a constant voltage device 72. Therefore, in the third modification, each of the inverters 26 to 28b inputs a DC voltage having a magnitude within a predetermined range output from the constant voltage device 72. As in the above embodiment, the inverters 26 to 28b drive the motors 30 to 32b according to the control instructions of the controller 25, respectively. Here, in the third modification, each of the inverters 26 to 28b inputs DC electricity and outputs AC electricity (three-phase AC electricity) having a desired frequency. Note that a general inverter that receives alternating current electricity inputs the alternating current electricity once into internal direct current, and then outputs alternating current electricity. In the third modification, there is no need to convert AC electricity into DC electricity inside the inverter, so that the configuration of each of the inverters 26 to 28b can be simplified. Also,

In the third modification, a power regulator 29 that inputs and outputs DC electricity is used. Similar to the above embodiment, the power regulator 29 controls the operation of the heating device 12 in accordance with the control instruction of the controller 25.

Next, the operation of the asphalt finisher in the third modification will be described. First, when the engine 21 is driven in a low rotation state, the generator 70 outputs a relatively low voltage. The output voltage of the generator 70 is a voltage lower than the predetermined range. In this case, the constant voltage device 72 boosts and outputs the DC voltage output from the rectifier 71 to a voltage within the predetermined range. As a result, a voltage within the range of the input allowable voltage is input to each of the inverters 26 to 28b.

On the other hand, when the engine 21 is driven in a high rotation state, the generator 22 outputs a relatively high voltage. Also in this case, the constant voltage device 72 adjusts and outputs the DC voltage output from the rectifier 71 to a voltage within the predetermined range. That is, the constant voltage device 72 performs boosting when the output voltage of the generator 22 is lower than the voltage within the predetermined range, and when the output voltage of the generator 22 is higher than the voltage within the predetermined range. Step down. When the output voltage of the generator 22 is a voltage within the predetermined range, the constant voltage device 72 does not have to substantially adjust the voltage. Thus, a voltage within the input allowable voltage range is input to each of the inverters 26 to 28b.

As described above, according to the third modification, the constant voltage device 72 is connected to the output side of the generator 70, and the constant voltage device 72 converts the input voltage into a voltage within a predetermined range. Output. As a result, in both cases where the engine 21 is in the low rotation state and in the high rotation state, the voltage input to each of the inverters 26 to 28b can be made constant and within the range of the input allowable voltage. Can be input to each of the inverters 26 to 28b. Therefore, according to the third modification, each of the inverters 26 to 28b can be operated normally, and each mechanism can be accurately controlled.

Further, according to the third modification, even if the rotational speed of the engine 21 fluctuates for some reason, the output voltage of the generator 70 is appropriately boosted or stepped down by the constant voltage device 72. Can also cope with. Further, according to the third modification, since the DC voltage is converted by the constant voltage device 72, the voltage is more accurately compared with the case of converting the AC voltage (sixth and seventh modifications described later). Adjustments can be made.

(Fourth modification)
FIG. 13 is a diagram illustrating an electrical configuration of an asphalt finisher according to a fourth modification. Note that FIG. 13 mainly shows portions that are different from FIG. 2, and a description of the same configuration as FIG. 2 is omitted. In the fourth modification example, the asphalt finisher has an automatic voltage regulator (abbreviated as “AVR (Automatic Voltage Regulator)” in FIG. 13) in addition to the configuration shown in FIG. 2. A detection transformer 79 is provided. In the fourth modification, the asphalt finisher includes a generator 80 instead of the above-described generator 22. The generator 80 has a generator body 74 and an excitation device 77. Although only a part of the asphalt finisher is shown in FIG. 13, the asphalt finisher includes the inverters 26 to 28b and the power regulator 29 as in the above embodiment. Although not shown in FIG. 13, a controller 25 is connected to each of the inverters 26 to 28b and the power regulator 29 as in the above embodiment, and each of the inverters 26 to 28b and the power regulator 29 is controlled by the controller 25. Is done.

In FIG. 13, the generator 80 is mechanically connected to the engine 21 and generates power by driving the engine 21. Specifically, the generator body 74 and the excitation device 77 are mechanically connected to the engine 21 and driven by the engine 21. The excitation device 77 controls the magnetic field in the generator main body 74 by controlling the current of the field coil 75 of the generator main body 74.

The automatic voltage regulator 73 adjusts the output voltage of the generator 80 so that a voltage within a predetermined range is output. The automatic voltage regulator 73 controls the field current of the generator 80 based on the output voltage of the generator 80. In other words, the automatic voltage regulator 73 adjusts the output voltage of the generator by changing the power generation characteristics of the generator 80 when the engine 21 is in the first rotation state and when the engine 21 is in the second rotation state. To do. That is, in the fourth modified example, the automatic voltage regulator 73 corresponds to the adjustment unit described in the claims.

Specifically, the automatic voltage regulator 73 controls the current supplied to the coil 78 of the excitation device 77 based on the output voltage of the generator 80 detected by the detection transformer 79. The excitation device 77 supplies a current corresponding to the current of the coil 78 to the field coil 75 of the generator main body 74 via the rotary rectifier 76. The automatic voltage regulator 73 controls the current of the field coil 75 so that the output voltage of the generator 80 becomes a set desired voltage value. As described above, the output voltage of the generator 80 is controlled to the value set by the automatic voltage regulator 73.

In the fourth modification, the output voltage of the generator 80 is adjusted by the automatic voltage regulator 73 regardless of whether the engine 21 is driven in a low rotation state or in a high rotation state. It becomes the value in. As a result, a voltage within the range of the input allowable voltage is input to each of the inverters 26 to 28b.

In the third and fourth modifications, the voltage input to the inverter can be adjusted without switching the wiring depending on whether the engine 21 is in a low rotation state or a high rotation state. Therefore, in the third and fourth modified examples, the output voltage of the generator can be adjusted without providing means for detecting whether the engine 21 is in a high rotation state or a low rotation state. .

(Fifth modification)
FIG. 14 is a diagram illustrating an electrical configuration of an asphalt finisher according to a fifth modification. In FIG. 14, portions different from those in FIG. 2 are mainly shown, and description of the same configuration as that in FIG. 2 is omitted. The asphalt finisher in the fifth modified example is different from the configuration shown in FIG. 12 in that it includes a booster 82 instead of the constant voltage device 72, and includes a switching unit 81 and a diode 83. This is the same as the third modification. Hereinafter, the fifth modification will be described with a focus on differences from the third modification.

In FIG. 14, the rectifier 71 has the same configuration as that of the third modified example. The switching unit 81 is connected to the output side of the rectifier 71. The switching unit 81 can switch between a path for inputting the output of the rectifier 71 to the inverters 26 to 28b as it is and a path for inputting the output of the rectifier 71 to the inverters 26 to 28b via the booster 82. . The path on the output side of the rectifier 71 is bifurcated, and one path is connected to each of the inverters 26 to 28b via the diode 83. The other path is connected to each of the inverters 26 to 28b via a switch 81a included in the switching unit 81 and a booster 82. That is, the output terminal of the rectifier 71 is connected to the anode terminal of the diode 83, and the cathode terminal of the diode 83 is connected to each of the inverters 26 to 28b. The output terminal of the rectifier 71 is connected to the input terminal of the booster 82 via the switch 81a, and the output terminal of the booster 82 is connected to each of the inverters 26 to 28b.

Although not shown, the switching unit 81 is connected to the controller 25, and the path switching in the switching unit 81 is controlled by the controller 25. That is, the connection / disconnection of the switch 81a is controlled by the controller 25.

Further, the booster 82 is connected to the rectifier 71 and boosts the DC electric voltage output from the rectifier 71 to a voltage within a predetermined range. That is, in the fifth modified example, the booster 82 corresponds to the adjustment unit described in the claims. The booster 82 may have any configuration as long as it has at least a function of boosting the input voltage, and may be configured by a general booster circuit or the like. Although details will be described later, in the fifth modified example, the booster 82 operates only when the generator 70 outputs a voltage lower than the predetermined range. Therefore, unlike the third modification, the booster 82 need not have a step-down function. Therefore, in the fifth modification, the configuration for adjusting the output voltage of the generator 70 can be further simplified.

In the fifth modification, when the engine 21 is driven in a low rotation state, the generator 70 outputs a relatively low voltage. The output voltage of the generator 70 is a voltage lower than the predetermined range. In this case, the controller 25 controls the switching unit 81 so that the output of the generator 70 is input to the booster 82. That is, the controller 25 controls to connect the switch 81a. Therefore, the booster 82 boosts and outputs the DC voltage output from the rectifier 71 to a voltage within the predetermined range. As a result, a voltage within the range of the input allowable voltage is input to each of the inverters 26 to 28b. The diode 83 is provided in order to prevent a reverse current flow when the booster 82 operates.

On the other hand, when the engine 21 is driven in a high rotation state, the generator 70 outputs a relatively high voltage. In the fifth modification, it is assumed that the voltage output from the generator 70 in this case is a value within the input allowable voltage range of the inverters 26 to 28b. In this case, the controller 25 controls the switching unit 81 so that the output of the generator 70 is not input to the booster 82. That is, the controller 25 controls the switch 81a to be disconnected. Therefore, the output from the rectifier 71 is directly input to the inverters 26 to 28b. Thus, as in the case of the high rotation state and the low rotation state, a voltage within the range of the input allowable voltage is input to each of the inverters 26 to 28b.

As described above, according to the fifth modification, when the engine 21 is in the low rotation state, the output of the generator 70 is input to the inverters 26 to 28b via the booster 82, and the engine 21 is In the rotating state, the power transmission path from the generator 70 to each of the inverters 26 to 28b is switched to the switching unit 81 so that the output of the generator 70 is input to each of the inverters 26 to 28b without passing through the booster 82. It is switched by. Thus, an appropriate voltage can be input to each of the inverters 26 to 28b in any state. Further, according to the fifth modified example, since the DC voltage is converted by the booster 82, the voltage adjustment is performed with higher accuracy than in the case of converting the AC voltage (sixth and seventh modified examples described later). It can be performed.

(Sixth Modification)
FIG. 15 is a diagram illustrating an electrical configuration of an asphalt finisher according to a sixth modification. In FIG. 15, portions different from those in FIG. 2 are mainly shown, and description of the same configuration as that in FIG. 2 is omitted. In the sixth modification, the asphalt finisher includes a switching unit 84 and a transformer 85 in addition to the configuration shown in FIG. In the sixth modification, the asphalt finisher includes a generator 70 similar to that in the third modification, instead of the above-described generator 22. Further, although only a part is shown in FIG. 16, the asphalt finisher includes inverters 26 to 28b and a power regulator 29 as in the above embodiment. Although not shown in FIG. 16, the controller 25 is connected to each of the inverters 26 to 28b and the power regulator 29 as in the above embodiment, and each of the inverters 26 to 28b and the power regulator 29 is controlled by the controller 25. Is done.

15, the switching unit 84 is connected to the generator 70. The switching unit 84 can switch between a path for inputting the output of the generator 70 as it is to each of the inverters 26 to 28 b and a path for inputting the output of the generator 70 to each of the inverters 26 to 28 b via the transformer 85. It is. The output side path of the generator 70 is bifurcated, and one path is connected to each of the inverters 26 to 28b via a switch 81a and a transformer 85 included in the switching unit 84. The other path is connected to each of the inverters 26 to 28b and the power regulator 29 via a switch 81b included in the switching unit 84. Although not shown, the switching unit 84 is connected to the controller 25, and path switching in the switching unit 84 is controlled by the controller 25. That is, connection / disconnection of the switches 83a and 83b is controlled by the controller 25.

The transformer 85 converts an input AC voltage (here, a three-phase AC voltage) into a voltage within the predetermined range and outputs the voltage. That is, in the sixth modification (and a seventh modification described later), the transformer 85 corresponds to the adjustment unit described in the claims. The type and specific configuration of the transformer 85 may be anything.

Next, the operation of the asphalt finisher in the sixth modification will be described. First, when the engine 21 is driven in a low rotation state, the generator 70 outputs a relatively low voltage. In this case, the controller 25 controls the switching unit 84 so that the output of the generator 70 is input to the transformer 85. That is, the controller 25 controls to connect the switch 83a and disconnect the switch 83b. Therefore, the transformer 85 boosts and outputs the three-phase AC voltage output from the generator 70 to a voltage within the predetermined range. As a result, a voltage within the range of the input allowable voltage is input to each of the inverters 26 to 28b.

On the other hand, when the engine 21 is driven in a high rotation state, the generator 70 outputs a relatively high voltage. In the sixth modification, it is assumed that the voltage output from the generator 70 in this case is a value within the range of the input allowable voltage of the inverters 26 to 28b. In this case, the controller 25 controls the switching unit 84 so that the output of the generator 70 is not input to the transformer 85. That is, the controller 25 controls to disconnect the switch 83a and connect the switch 83b. Therefore, the three-phase AC electricity output from the generator 70 is input to the inverters 26 to 28b as they are. Thus, as in the case of the high rotation state and the low rotation state, a voltage within the range of the input allowable voltage is input to each of the inverters 26 to 28b.

As described above, according to the sixth modification, when the engine 21 is in the low rotation state, the output of the generator 70 is input to each of the inverters 26 to 28b via the transformer 85, and the engine 21 is In the rotating state, the power transmission path from the generator 70 to each of the inverters 26 to 28b is switched to the switching unit 84 so that the output of the generator 70 is input to each of the inverters 26 to 28b without passing through the transformer 85. It is switched by. Thus, an appropriate voltage can be input to each of the inverters 26 to 28b in any state.

(Seventh Modification)
FIG. 16 is a diagram illustrating an electrical configuration of an asphalt finisher according to a seventh modification. In FIG. 16, portions different from those in FIG. 2 are mainly shown, and description of the same components as those in FIG. 2 is omitted. The asphalt finisher in the seventh modified example is different from the configuration of the sixth modified example shown in FIG. 15 in that an automatic voltage regulator 73 and a detection transformer 79 are provided. Further, in the seventh modification, the asphalt finisher includes a generator 80 similar to that in the fourth modification, instead of the generator 70 in the sixth modification. Hereinafter, the fifth modification will be described with a focus on differences from the sixth modification.

In FIG. 16, the generator 80 and the automatic voltage regulator 73 have the same configuration as that of the fourth modified example. In the seventh modification, the detection transformer 79 is connected to the output side of the transformer 85. The automatic voltage regulator 73 adjusts the output voltage of the generator 80 so that the voltage at the output terminal of the transformer 85 (and the switch 84b) becomes a voltage within a predetermined range. That is, the automatic voltage regulator 73 controls the current of the field coil 75 so that the voltage at the output terminal of the transformer 85 (and the switch 84b) becomes a set desired voltage value.

Also in the seventh modification, the controller 25 and the switching unit 84 operate in the same manner as in the sixth modification. Therefore, the output voltage of the generator 80 is adjusted within the predetermined range whether the engine 21 is in a low rotation state or a high rotation state. Here, voltage conversion by the transformer 85 that converts AC voltage is generally difficult to perform detailed voltage adjustment compared to voltage conversion by the constant voltage device 72 (boost device 82) that converts DC voltage. On the other hand, in the seventh modification, the voltage at the output terminal of the transformer 85 (and the switch 84b) is also adjusted by the automatic voltage regulator 73, so that the voltage adjustment is performed in more detail (with high accuracy). )It can be carried out. In addition, even when there is some fluctuation in the rotational speed of the engine 21 in the high rotation state, the output voltage of the generator 70 is adjusted by the automatic voltage regulator 73, so that the input voltage to each of the inverters 26 to 28b is adjusted. It can be made more stable.

As described above, in the fifth to seventh modification examples, the switching

unit

81 or 84 has the output of the generator adjusted when the engine 21 is in a low rotation state (the booster 82 or the transformer 85). To the inverters 26 to 28b, and when the engine 21 is in a high rotation state, the generator outputs each of the inverters 26 to 28b so that the output of the generator is not input to the inverters 26 to 28b. The power transmission path to the inverters 26 to 28b is switched. Therefore, since the output voltage of the generator is adjusted by the adjustment unit in the low rotation state, an appropriate voltage can be input to each of the inverters 26 to 28b. Further, since the generator outputs a voltage within a predetermined range in the high rotation state, an appropriate voltage is applied to each inverter 26 to 28b by inputting the output voltage of the generator as it is to each inverter 26 to 28b. Can be entered. In the fifth to seventh modifications, the adjustment unit does not need to correspond to the output voltage when the engine 21 is in the high rotation state, and therefore the adjustment unit can be configured more simply.

In the fifth to seventh modifications, any method may be used for detecting whether the engine 21 is in a low rotation state or a high rotation state, as in the above embodiment. For example, the controller 25 may detect whether the engine is in a low rotation state or a high rotation state based on an instruction from the user or the rotational speed of the engine 21 or the generator 22.

As described above, the present invention is applied to a road paving machine for paving asphalt roads such as asphalt finishers, repavers, and remixers for the purpose of improving energy efficiency and reducing carbon dioxide emissions. Is possible.

DESCRIPTION OF SYMBOLS 1 Asphalt finisher 2 Car body 3 Hopper 4 Front wheel 5 Rear wheel 6 Conveyor 7 Screw 8 Leveling arm 11 Screed 12 Heating device 13 Vibrator 21 Engine 22 Generator 23 Operation panel 24 Control box 25 Controllers 26 to 28b, 51 Inverter 29 Power regulator 30 33b, 52a to 52d Motor 41 Three-phase coils 42a to 42c Switch 61 Power plug 62 Changeover switch 70 Generator 71 Rectifier 72 Constant voltage device 73 Automatic voltage regulator 80 Generator 81 Switching unit 82 Booster 84 Switching unit 85 Transformer

Claims

A road paving machine having a traveling mechanism, a conveyor, a screw, and a screed mechanism, and paving an asphalt road,
Engine,
A generator for generating electricity by driving the engine;
Each motor that drives each mechanism with electric power from the generator;
The output voltage of the generator is in a predetermined range in both the case where the engine is in a first rotation state where the engine speed is relatively low and the case where the engine is in a second rotation state where the engine speed is relatively high. An adjustment unit that adjusts the output voltage of the generator so as to be a voltage within,
A road paving machine comprising: an inverter that converts an output of the generator, the voltage of which has been adjusted by the adjusting unit, into a desired frequency and supplies the inverter to each motor.
The road paving machine according to claim 1, wherein the adjustment unit is connected to an output side of the generator and converts an input voltage into a voltage within the predetermined range and outputs the converted voltage.
A rectifier that converts alternating current electricity output from the generator into direct current electricity;
The road paving machine according to claim 2, wherein the adjustment unit includes a constant voltage device that converts the voltage of the DC electricity into a voltage within the predetermined range.
The said adjustment part adjusts the output voltage of the said generator by changing the electric power generation characteristic of the said generator between the case where the said engine is a 1st rotation state, and the case where it is a 2nd rotation state. Road paving machine as described in
When the engine is in the first rotation state, the output of the generator is input to the inverters via the adjustment unit, and when the engine is in the second rotation state, the output of the generator is input. Is further provided with a switching unit that switches a power transmission path from the generator to each of the inverters so that it is input to each of the inverters without going through the adjustment unit,
The generator outputs the voltage within the predetermined range when the engine is in the second rotation state,
The road paving machine according to claim 1, wherein the adjustment unit converts an output voltage of the generator into a voltage within the predetermined range when the engine is in the second rotation state.
A rectifier that converts alternating current electricity output from the generator into direct current electricity;
The switching unit switches the power transmission path of the DC electricity,
The road paving machine according to claim 5, wherein the adjustment unit includes a booster that boosts the voltage of the DC electricity to a voltage within the predetermined range.
The road paving machine according to claim 5, wherein the adjustment unit includes a transformer that transforms AC electricity output from the generator.
The road paving machine according to claim 7, further comprising an automatic voltage regulator for controlling a field current of the generator based on an output voltage of the generator.
A heating device for heating the screed by the electric power generated by the generator;
A control device for controlling the operation of each inverter and the heating device;
The generator can be switched between a first mode and a second mode having different power generation characteristics, and the first mode generates power generated when the engine is at the first rotational speed. The second mode is a mode in which the generated power is higher than that in the first mode when the engine has a second rotational speed lower than the first rotational speed. The road paving machine according to claim 1, wherein the road paving machine is also a mode of increasing.
The generator includes a generator configured to have a relatively small number of coil turns in the first mode and a relatively large number of coil turns in the second mode. 9. Road paving machine according to 9.
The road paving machine according to claim 10, wherein the generator outputs at least electric power necessary for the operation of the heating device in the second mode.
A detector that detects the number of revolutions of the engine;
The road pavement machine according to claim 9, wherein the control device switches between the first mode and the second mode according to a detection result of the detection unit.
The road according to claim 9, wherein the control device controls operations of the motors and the heating device so that a total power consumption of the motors and the heating device does not exceed a generated power of the generator. Paving machine.
The road pavement machine according to claim 13, wherein, when starting any two or more of the motors and the heating devices, the control device starts the motors and the heating devices at different start timings. .
The road paving machine according to claim 13, wherein the control device temporarily stops or reduces the power supply to the heating device when starting at least one of the motors.
The control device calculates total power consumption of each motor and the heating device, and stops power supplied to at least one of the motors and the heating device when the total power consumption is a predetermined value or more. 14. A road paving machine according to claim 13, wherein the road paving machine is reduced.
A vibrator for vibrating the screed;
The road paving machine according to claim 9, further comprising a vibrator motor that drives the vibrator with electric power generated by the generator.
Further provided with a power supply terminal for obtaining external power,
The road paving machine according to claim 9, wherein the control device is capable of switching between electric power from the generator and electric power from the power supply terminal.
A road paving machine having a traveling mechanism, a conveyor, a screw, and a screed mechanism, and paving an asphalt road,
Engine,
A generator for generating electricity by driving the engine;
Each motor that drives each mechanism with electric power from the generator;
A heating device for heating the screed by the electric power generated by the generator;
A control device for controlling the operation of each inverter and the heating device;
The road paving machine, wherein the control device controls operations of the motors and the heating device so that total power consumption of the motors and the heating device does not exceed the power generated by the generator.