JP6118713B2 - Asphalt finisher - Google Patents

Description

  The present invention relates to an asphalt finisher that electrically heats a screed plate with an electric heater.

  The asphalt finisher has a screed device that spreads an asphalt heating mixture and smoothes the road pavement surface smoothly. In this screed device, a screed plate is disposed on the lower surface portion, and the screed plate performs the above-described smoothing and the like on the asphalt heating mixture.

  This screed apparatus heats the screed plate during construction in order to finish the pavement surface smoothly and prevent the asphalt heating mixture and the like from adhering to the screed plate.

  As a means for heating the screed plate, for example, an electric heating type is known in which an electric heater such as a high-frequency induction coil is disposed on the entire surface of the screed plate and the electric heater is heated by supplying electric power. (See Patent Document 1).

JP 2013-014939 A

  As described above, in the asphalt finisher using the electric heating method for heating the screed plate, a generator driven by an engine is generally used as a power source of the electric heater.

  At the start of construction, since it is before heating, the screed plate having a temperature substantially equal to the outside air temperature is heated to an appropriate heating temperature suitable for construction (this process is referred to as preparatory heating process). When this preparatory heating process was performed, the output of the generator was set to the maximum output (100% output).

  By the way, asphalt finishers are used in a wide range of temperature environments where the outside air temperature is below 50 ° C. or more depending on the destination. In such a case, the generator can sufficiently exhibit its performance under a low temperature atmosphere, but the self-cooling function of the generator decreases and the output is also limited as the temperature increases.

  However, the conventional electric heater control device does not reflect the outside air temperature in the control of the electric heater. Moreover, the output of the generator was set to the maximum output during the preparation heating as described above.

  For this reason, there is a possibility that the output will exceed the limit of the generator in a high temperature atmosphere. In this case, there is a possibility that the generator life will be reduced, and in the worst case, it may be damaged.

  One exemplary object of one aspect of the present invention is to provide an asphalt finisher that can heat the screed plate within the limits of the generator regardless of the outside air temperature.

According to one aspect of the invention,
A screed device for heating the screed plate with an electric heater;
A generator for generating electric power to be supplied to the electric heater;
A power amount setting device for setting a power amount to be supplied from the generator to the electric heater;
An outside temperature sensor for measuring the outside temperature;
A control device that controls the power amount setting device based on the outside air temperature detected by the outside air temperature sensor, and varies the amount of power supplied to the electric heater in accordance with the outside air temperature;
Is provided.

According to an aspect of the present invention, it is possible to protect the generator, reduce the weight, and improve the power generation efficiency.

FIG. 1A is a schematic configuration diagram of an asphalt finisher according to an embodiment, and FIG. 1B is a plan view illustrating a schematic configuration of a screed device of the asphalt finisher according to an embodiment. FIG. 2 is a rear view for explaining an electric heater provided in a screed device of an asphalt finisher according to an embodiment. FIG. 3 is a plan view for explaining an electric heater provided in a screed device of an asphalt finisher according to an embodiment. FIG. 4 is a diagram illustrating a control system of an electric heater provided in a screed device of an asphalt finisher according to an embodiment. FIG. 5 is a flowchart showing a control process of an electric heater provided in a screed device of an asphalt finisher according to an embodiment. FIG. 6 is a flowchart showing a control process of an electric heater provided in a screed device of an asphalt finisher according to another embodiment. FIG. 7 is a diagram showing an example of a table used for the electric heater control process shown in FIG. FIG. 8 is a diagram illustrating an example of a table used for the electric heater control process illustrated in FIG. 6.

  Reference will now be made to non-limiting exemplary embodiments of the invention with reference to the accompanying drawings.

  In the description of all the attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and repeated description will be omitted as appropriate. Also, the drawings are not intended to show relative ratios between members or parts unless otherwise specified. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

  In addition, the embodiments described below are examples, not limiting the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 shows a schematic configuration of an asphalt finisher 10 according to an embodiment of the present invention. FIG. 1A is a schematic view showing a partial cross section of the asphalt finisher 10, and FIG. 1B is a plan view showing a schematic configuration of the screed device 24 of the asphalt finisher 10.

  The asphalt finisher 10 includes a traveling main body 20 and a screed device 24 as shown in FIG. The traveling main body 20 is provided with a hopper 21 in which an asphalt heating mixture (hereinafter referred to as “mixture”) K is loaded at the front thereof.

  In addition, a conveyor 22 that conveys the mixture K loaded on the hopper 21 is provided at the lower part of the vehicle body behind the hopper 21 of the traveling main body 20. Further, a screw spreader 23 is provided behind the conveyor 22 of the traveling main body 20. The screw spreader 23 has screw blades on the outer periphery of the screw shaft, and spreads the mixture K dropped on the road surface from the conveyor 22 in the road surface width direction.

  The screed device 24 is provided behind the traveling main body 20. The screed device 24 spreads and spreads the spread mixture K and finishes the paved surface smoothly.

  The traveling main body 20 travels by a pair of rear wheels 25 a and 25 b and a pair of front wheels 26 a and 26 b and pulls the screed device 24. An operation unit 27 is provided in the driver's seat of the traveling main body unit 20. The operation unit 27 is equipped with various operation levers, operation switches, and the like for operating the conveyor 22, the screed device 24, and the like during pavement processing.

  As shown in FIG. 1B, the screed device 24 includes a front screed plate 30 that is arranged in the center and spreads the mixture K with a predetermined paving width, and a left side of the front screed plate 30 in the figure (arrow X1 in the figure). A left screed plate 31 disposed on the direction side and a right screed plate 32 disposed on the right side (the arrow X2 direction side in the drawing).

  The left screed plate 31 and the right screed plate 32 are configured to be movable with respect to the front screed plate 30 in the longitudinal direction of the front screed plate 30 (directions of arrows X1 and X2 in the drawing). Therefore, the overall length in the width direction of each screed plate 30, 31, 32 (length in the direction of arrows X1, X2 in the drawing) can be adjusted by moving the left screed plate 31 and the right screed plate 32. It has become. Thereby, it becomes possible to arbitrarily set the pavement width.

  The screed device 24 needs to heat the screed plates 30, 31, 32 in order to finish the pavement surface smoothly and prevent the mixture K and the like from adhering to the screed plates 30, 31, 32. In the present embodiment, an electric heating method is used to heat the screed plates 30, 31 and 32. Therefore, the screed device 24 is provided with an electric heater 40 for heating the front screed plate 30, an electric heater 41 for heating the left screed plate 31, and an electric heater 42 for heating the right screed plate 32.

  Next, the attachment structure of the electric heaters 40, 41, 42 to the screed plates 30, 31, 32 will be described. In addition, since the attachment structure of the electric heaters 40, 41, and 42 to each screed plate 30, 31, and 32 is substantially equal, in the following description, the attachment structure of the electric heater 40 to the front screed plate 30 will be described with reference to FIGS. Only the description will be given, and the description of the mounting structure of the electric heaters 41 and 42 to the other screed plates 31 and 32 will be omitted.

  As shown in FIG. 2, the front screed plate 30 is disposed on the lower surface portion of the screed device 24. The left end of the front screed plate 30 (the end on the arrow X1 direction side in the drawing) is supported by the left frames 33, 35, and 36 as shown in FIG. (In the figure, the end on the arrow X2 direction side) is supported by the right frames 34, 35, and 36.

  As shown in FIG. 3, the electric heater 40 includes a first heater 40A and a second heater 40B. The energization of the first and second heaters 40A and 40B can be switched independently of each other. As a result, even if one heater breaks down, paving work can be performed with the other heater, so that redundancy with respect to the front screed plate 30 is ensured.

  As will be described later, the electric heaters 40, 41, 42 are supplied with electric power from a generator 47. The electric heaters 40, 41, and 42 generate heat due to the supply of electric power from the generator 47, whereby the front screed plates 30, 31, and 32 are heated.

  Next, a control system of the electric heater that performs the heating control process for the electric heaters 40, 41, and 42 will be described with reference to FIG. In FIG. 4, for convenience of illustration, the electric heaters 40, 41, and 42 are shown as one heater. In addition, an electromagnetic proportional valve 45, a hydraulic motor 46, and a heater temperature adjusting device 55, which will be described later, are illustrated in two places in FIG. 4 for convenience of illustration, but are actually one device.

  The asphalt finisher 10 mainly includes a heater controller 50 that controls the heaters 40, 41, and 42 of the screed device 24, a traveling body controller 51 that mainly controls the traveling body 20, and a conveyor control that controls the conveyor 22. And a controller 52. The controllers 50, 51, 52 are connected by a bus line 53, and are configured to exchange data with each other.

  The engine 43 drives the hydraulic pump 44. When the hydraulic pump 44 is driven, the oil in the oil tank OT is supplied to the hydraulic motor 46 via the electromagnetic proportional valve 45, and the hydraulic motor 46 rotates the drive shaft. The generator 47 is connected to the drive shaft of the hydraulic motor 46, and the generator 47 generates power when the drive shaft rotates.

  The oil pressure sensor 49 detects the oil pressure of the oil that the hydraulic pump 44 supplies to the hydraulic motor 46. The oil pressure detected by the oil pressure sensor 49 is transmitted to the heater controller 50.

  The travel body controller 51 controls the rotation of the hydraulic motor 46. Also, the travel main body controller 51 receives information on the oil pressure detected by the hydraulic sensor 49 from the heater controller 50. When the oil hydraulic pressure becomes equal to or higher than a predetermined value, the traveling main body controller 51 closes the electromagnetic proportional valve 45 to prevent the hydraulic motor 46 from over-rotating.

  The generator 47 is connected to each electric heater 40, 41, 42 provided in the screed device 24 via a breaker 48 and a heater temperature adjustment device 55. Therefore, each electric heater 40, 41, 42 is heated by the electric power supplied from the generator 47.

  The breaker 48 stops the power supply from the generator 47 to each of the electric heaters 40, 41, 42 when an excessive current flows through the electric heaters 40, 41, 42. The heater temperature adjusting device 55 controls the amount of electrode supplied to each electric heater 40, 41, 42.

  The heater temperature adjusting device 55 is connected to the heater control controller 50. Therefore, the output (heating amount) of each electric heater 40, 41, 42 is controlled by the heater controller 50. For convenience of explanation, details of the heater temperature adjusting device 55 will be described later.

  The heater controller 50 is connected to heating temperature sensors 37, 38, 39, a hydraulic pressure sensor 49, a heater temperature adjusting device 55, a mode changeover switch 60, a display device 62, an outside air temperature sensor 70, and the like.

  The heating temperature sensor 37 measures the temperature of the front screed plate 30. The heating temperature data of the front screed plate 30 measured by the heating temperature sensor 37 is transmitted to the heater controller 50. Similarly, the heating temperature data of the left screed plate 31 measured by the heating temperature sensor 38 and the heating temperature data of the right screed plate 32 measured by the heating temperature sensor 39 are also transmitted to the heater controller 50.

  The hydraulic sensor 49 detects the hydraulic pressure of oil supplied from the hydraulic pump 44 to the hydraulic motor 46 as described above, and the heater controller 50 controls the hydraulic motor 46 based on hydraulic data transmitted from the hydraulic sensor 49. To do.

  The mode change switch 60 is provided in the operation unit 27. The asphalt finisher 10 according to the present embodiment has at least two control modes when performing pavement construction. One is a preparation mode and the other is a construction mode. The preparation mode and the construction mode can be switched by operating the mode changeover switch 60 by an operator (driver) of the asphalt finisher 10.

  In this embodiment, an example in which a rotary switch is applied as the mode switch 60 is shown, but the present invention is not limited to this. Further, the mode changeover switch 60 can be in a cut-off state in which neither the preparation mode nor the construction mode is performed. In the present embodiment, the mode changeover switch 60 has the preparation mode on one side and the construction mode on the other side across the cut position, but is not limited thereto. Furthermore, other modes can be added.

  Here, the preparation mode is a predetermined temperature (hereinafter referred to as “this temperature”) suitable for paving each screed plate 30, 31, 32 that is substantially equal to the outside temperature (environmental temperature) on the road surface. In this mode, the temperature is heated to a predetermined heating temperature.

  On the other hand, the construction mode is a mode in which the screed plates 30, 31, 32 that have reached the predetermined heating temperature by performing the preparation mode are controlled so as to maintain the predetermined heating temperature (so as to be kept warm). . The predetermined heating temperature can be adjusted with a heating temperature setting switch (not shown) provided in the operation unit 27.

  The display device 62 is disposed in the operation unit 27. This display device 62 is necessary for pavement processing such as the temperature of each screed plate 30, 31, 32 measured by the heating temperature sensors 37, 38, 39 and the predetermined heating temperature set by the heating setting switch. Various information is displayed.

  The outside air temperature sensor 70 is a sensor that measures the temperature of outside air. Outside air temperature data measured by the outside air temperature sensor 70 is transmitted to the heater controller 50. The arrangement position of the outside air temperature sensor 70 is set to a position that is not affected by the heat generated by various devices and equipment.

  On the other hand, the traveling body controller 51 is connected to various devices and devices for controlling the driving of the traveling body 20. In the example shown in FIG. 4, among various devices and equipment connected to the travel main body controller 51, an electric proportional valve 45, a hydraulic motor 46, and an appropriate temperature are used for supplying power to and controlling the electric heaters 40, 41, 42. Only the indicator lamp 64 is shown.

  The traveling body controller 51 controls the electromagnetic proportional valve 45 and the hydraulic motor 46 so that the generator 47 generates stable electric power. The appropriate temperature indicator lamp 64 is turned on by the traveling main body controller 51 when each screed plate 30, 31, 32 reaches a predetermined temperature, as will be described later.

  Each device / device is also connected to the conveyor controller 52, but since there is nothing directly related to the above-described preparation mode and construction mode, the illustration is omitted in FIG.

  Next, the heater temperature adjusting device 55 will be described.

  The heater temperature adjusting device 55 includes three solid state relays 56, 57, and 58 (hereinafter abbreviated as SSR) corresponding to the three electric heaters 40, 41, and 42. The electric power generated by the generator 47 is branched into three and supplied to the SSRs 56, 57 and 58.

  The SSR 56 is connected to an electric heater 40 that heats the front screed plate 30 (hereinafter, the SSR 56 is referred to as a front heater SSR 56). The SSR 57 is connected to an electric heater 41 that heats the left screed plate 31 (hereinafter, the SSR 57 is referred to as a left heater SSR 57). The SSR 58 is connected to an electric heater 42 that heats the right screed plate 32 (hereinafter, the SSR 58 is referred to as a right heater SSR 58).

  Further, each SSR 56, 57, 58 is connected to the heater controller 50. The heater controller 50 and the heater temperature adjustment device 55 (SSRs 56, 57, 58) perform chopper control of electric power supplied to the electric heaters 40, 41, 42. Therefore, the heating amount of the electric heaters 40, 41, 42 is controlled by the heater controller 50 and the heater temperature adjusting device 55, and the temperature of each screed plate 30, 31, 32 is also controlled accordingly.

  Next, the temperature control process of each screed plate 30, 31, 32 performed by the heater controller 50 will be described. The heater controller 50 performs different control in the preparation mode and the construction mode.

  First, a temperature control process performed by the heater controller 50 in the preparation mode will be described. In the following description, it is assumed that the heating temperature is set to 120 ° C. in advance by the heating temperature setting switch provided in the operation unit 27.

  In the following description, the temperature set by the heating temperature setting switch is referred to as a set heating temperature. Further, in the following description, an example in which the set heating temperature is set to 120 ° C. will be described. However, the set heating temperature is not limited to 120 ° C., and may be appropriately set by various personnel such as the type of the mixture K. Is possible.

  FIG. 5 is a flowchart showing an embodiment of the temperature control process in the preparation mode (hereinafter simply referred to as the preparation mode process) performed by the heater controller 50. FIG. 7 shows a table (hereinafter referred to as an output setting table) used when performing the preparation mode processing shown in FIG.

  The process in the preparation mode shown in FIG. 5 is started when the engine 43 is started, for example. Further, for example, it is activated when the mode switch 60 is switched from the off position to another mode such as the preparation mode. When the process in the preparation mode is started, the heater controller 50 determines whether or not the mode changeover switch 60 is in the preparation mode (preparation mode ON) in step 10 (“step” is abbreviated as “S” in the figure). Or not).

  When the mode changeover switch 60 is not in the preparation mode (in the case of NO determination), the processing in the preparation mode is terminated without performing the processing after step 11. On the other hand, when the mode changeover switch 60 is in the preparation mode in step 10 (in the case of YES determination), the process proceeds to step 11.

  In step 11, the heater controller 50 obtains the current outside air temperature T based on the outside air temperature data sent from the outside air temperature sensor 70. In subsequent step 12, it is determined whether or not the outside air temperature T obtained in step 11 is 40 ° C. or higher.

  When the heater controller 50 determines that the outside air temperature T is less than 40 ° C. (NO determination), the process proceeds to step 13. In step 13, the heater controller 50 sets the amount of electric power that each SSR 56, 57, 58 supplies to the electric heaters 40, 41, 42 based on the output setting table shown in FIG.

  As described above, the SSRs 56, 57, and 58 perform chopper control on the amount of power supplied to the electric heaters 40, 41, and 42. For this reason, the heater controller 50 is based on the output setting table shown in FIG. 7, and the ratio (DUTY value) of the time during which voltage is applied to the electric heaters 40, 41, 42 (ON time) and the time during which no voltage is applied (OFF time). This sets the amount of power supplied to the electric heaters 40, 41, 42.

  The output setting table shown in FIG. 7 is a table showing the relationship between the outside air temperature and the duty values of the SSRs 56, 57, and 58 (this is equivalent to the control value of each electric heater). In the present embodiment, as shown in the output setting table of FIG. 7, the outside air temperature T obtained from the output of the outside air temperature sensor 70 is divided into less than 40 ° C. and 40 ° C. or more.

  In the state before starting of the asphalt finisher 10, the temperature of each screed plate 30, 31, 32 is a temperature substantially equal to the outside air temperature. Therefore, in order to raise each screed plate 30,31,32 which is less than 40 degreeC to setting heating temperature (120 degreeC), it is necessary to heat each screed plate 30,31,32 80 degreeC or more.

  For this reason, in this embodiment, when the temperature of each screed plate 30, 31, 32 (that is, the outside air temperature T) is a low temperature of less than 40 ° C., the duty values of SSRs 56, 57, 58 as shown in FIG. Is set to 100%.

  Therefore, when it is determined in step 13 that the outside air temperature T is less than 40 ° C., the heater controller 50 sets the duty values of the SSRs 56, 57, and 58 to 100% based on the output setting table shown in FIG. Thereby, each electric heater 40,41,42 becomes 100% output, and each screed plate 30,31,32 is heated by each electric heater 40,41,42 to preset heating temperature.

  On the other hand, the generator 47 performs self-cooling during power generation as described above. However, when the outside air temperature T is as low as less than 40 ° C., the duty values of the SSRs 56, 57, and 58 are set to 100%, and the generator 47 outputs full power (100% output). The machine 47 is reliably self-cooled. Therefore, even when the output of the generator 47 is set to the full output when the outside air temperature T is less than 40 ° C., the generator 47 does not exceed the power generation limit or the life of the generator 47 is not reduced. .

  On the other hand, if it is determined in step 12 that the outside air temperature T is 40 ° C. or higher (YES determination), the heater controller 50 advances the process to step 14.

  Also in step 14, the heater controller 50 controls the SSRs 56, 57, and 58 based on the output setting table shown in FIG. When the processing of step 14 is performed, since the outside air temperature T is 40 ° C. or higher, the temperature of each screed plate 30, 31, 32 in the pre-starting state of the asphalt finisher 10 is almost equal to the outside air temperature and is a high temperature of 40 ° C. It has become. Therefore, each screed plate 30, 31, 32 can be raised to the set heating temperature (120 ° C.) with a smaller heating amount than in the case of step 13 described above.

  For this reason, in this embodiment, when the temperature of each screed plate 30, 31, 32 (that is, the outside air temperature T) is 40 ° C. or higher, the duty values of SSRs 56, 57, 58 are set to 80 as shown in FIG. %.

  Therefore, when it is determined in step 14 that the outside air temperature T is 40 ° C. or higher, the heater controller 50 sets the duty values of the SSRs 56, 57, and 58 to 80% based on the output setting table shown in FIG. Thereby, each electric heater 40,41,42 becomes 80% output, and each screed plate 30,31,32 is heated by this electric heater 40,41,42 to preset heating temperature under this output.

  On the other hand, in a high temperature atmosphere where the outside air temperature T at which the step 14 is performed is 40 ° C. or higher, the self-cooling function of the generator 47 decreases as the temperature rises, and the power generation output is also limited. As described above, when the generator 47 is fully operated in such a state, the neglected output of the generator 47 exceeds the limit, and the life of the generator 47 is reduced.

  Since the upper limit of the power generation amount that can be taken out from the generator is determined by the outside air temperature T, in order to increase the power generation amount of the generator at a high outside air temperature, it is necessary to enlarge the generator itself. However, when the generator is increased in size, the weight of the generator increases and a large arrangement space is required in the traveling main body.

  However, when the outside air temperature T is high, each screed plate 30, 31, 32 is also at a high temperature corresponding to the outside air temperature T. In this way, when the screed plates 30, 31, 32 have a high temperature, the screed plates 30, 31, 32 can be turned on even if the output of each electric heater 40, 41, 42 is not necessarily 100%. It is possible to heat up to a preset heating temperature.

  Therefore, in the present embodiment, the output of the electric heaters 40, 41, and 42 is variable according to the outside air temperature T. Specifically, the heater controller 50 outputs 100% of the output of the electric heaters 40, 41, 42 when the outside air temperature T is low, and outputs 80% of the output of the electric heaters 40, 41, 42 when the outside air temperature T is high. Variable.

With this configuration, the screed plates 30, 31, and 32 are set to the set heating temperature by the electric heaters 40, 41, and 42 without increasing the size of the generator 47 and without exceeding the power generation limit of the generator 47. Can be reliably heated. Moreover, the generator 47 can be reduced in weight and the installation space can be reduced without increasing the size of the generator 47. Furthermore, since the output of the electric heater 40, 41 is reduced, it is possible to reduce the power consumption, increasing the efficiency in heating the screed plate 30, 31 and 32 to set the heating temperature _{T 0} it can.

When the process of step 13 or step 14 is completed, the process proceeds to step 15, the heater controller 50 determines whether the temperature of each screed plate 30, 31, 32 reaches a set heating temperature T _0. Specifically, the heater controller 50 determines whether each screed plate 30, 31, 32 has been heated to the set heating temperature based on the heating temperature data sent from the heating temperature sensors 37, 38, 39.

If it is determined in step 15 that each screed plate 30, 31, 32 is not heated to the set heating temperature (NO determination), the heater controller 50 returns the process to step 11. The heater controller 50, the disk until the lead plates 30, 31 and 32 is set heating temperature _{T 0,} repeatedly executes the processing in step 15 from step 11.

  On the other hand, if it is determined in step 15 that each screed plate 30, 31, 32 has been heated to the set heating temperature (YES determination), the process proceeds to step 16. In step 16, the heater controller 50 turns on the appropriate temperature indicator lamp 64 provided in the operation unit 27. Thereby, the operator of the asphalt finisher 10 can recognize that each screed plate 30, 31, 32 has been heated to the set heating temperature.

The asphalt finisher 10 according to the present embodiment can maintain the preparation mode even after each screed plate 30, 31, 32 is heated to the set heating temperature T ₀ as long as the operator does not switch the mode changeover switch 60. . Therefore, in the following step 17, it is determined whether or not the mode changeover switch 60 is maintaining the preparation mode.

  If it is determined in step 17 that the mode changeover switch 60 is maintaining the preparation mode (YES determination), the heater controller 50 returns the process to step 11 and repeats the processes of steps 11 to 17. carry out.

  On the other hand, when the mode changeover switch 60 is switched at step 17 to enter the construction mode or the cut state, the preparation mode processing shown in FIG. 5 is terminated.

  Next, another embodiment of the preparation mode process executed by the heater controller 50 will be described.

  FIG. 6 is a flowchart showing another embodiment of the preparation mode processing performed by the heater controller 50. FIG. 8 shows an output setting table used when the preparation mode processing shown in FIG. 6 is performed.

  In the description of the other embodiment of the preparation mode process shown in FIG. 6, the description of the same process as the preparation mode process described with reference to FIGS. 5 and 7 will be omitted as appropriate.

  The preparation mode process shown in FIG. 6 is also started by starting the engine 43 or the like. Further, for example, it is activated when the mode switch 60 is switched from the off position to another mode such as the preparation mode. Steps 20 and 21 of the preparation mode processing shown in FIG. 6 are the same as steps 10 and 11 of the preparation mode processing shown in FIG.

  That is, in step 20, the heater controller 50 determines whether or not the mode changeover switch 60 is in the preparation mode (preparation mode ON), and if the mode changeover switch 60 is in the preparation mode (YES) In the case of determination), the current outside air temperature T is measured based on the outside air temperature data sent from the outside air temperature sensor 70 in step 21.

  In the subsequent step 22, the heater controller 50 supplies the electric power supplied to the electric heaters 40, 41, and 42 by the SSRs 56, 57, and 58 based on the outside air temperature T obtained in step 21 and the output setting table shown in FIG. 8. Set up.

  In the output setting table shown in FIG. 7, when determining the DUTY value of each SSR 56, 57, 58, the outside air temperature is 40 ° C. as a threshold value, and when the outside air temperature is less than 40 ° C., the DUTY value is set. When the temperature was 100% and 40 ° C. or higher, the DUTY value was 80%.

  On the other hand, in the output setting table used in the present embodiment shown in FIG. 8, the outside air temperature serving as a threshold is subdivided. Specifically, in this embodiment, the outside air temperature serving as a threshold is less than 0 ° C. (shown as 0 ° C.), 0 ° C. or more and less than 20 ° C. (shown as 0 ° C. to 20 ° C.), 20 ° C. or more and less than 40 ° C. (Shown as 20 ° C to 40 ° C), 40 ° C or higher and lower than 60 ° C (shown as 40 ° C to 60 ° C), 60 ° C or higher (shown as 60 ° C or higher).

  When the outside air temperature T is less than 0 ° C, each screed plate 30, 31, 32 is also less than about 0 ° C. Therefore, in order to set each screed plate 30, 31, 32 to the set heating temperature (120 ° C.), it is necessary to raise each screed plate 30, 31, 32 by 120 ° C. or more (this temperature is referred to as a temperature rise ΔT). There is. The temperature rise temperature ΔT is represented by (temperature rise temperature ΔT) = (set heating temperature T0) − (outside air temperature T).

  Further, when the outside air temperature T is low, the self-cooling function of the generator 47 works properly as described above, and therefore it is not necessary to limit the generator output. For this reason, when the outside air temperature T is less than 0 ° C., the DUTY values of the SSRs 56, 57, and 58 are set to 100%.

  When the outside air temperature T is 0 ° C. or higher and lower than 20 ° C., the temperature increase temperature ΔT is 100 ° C. or higher and lower than 120 ° C. Therefore, when the outside air temperature T is 0 ° C. or more and less than 20 ° C., the DUTY value of each of the SSRs 56, 57, 58 is set to 0 ° C. in consideration of the temperature rise temperature ΔT and the ability of the self-cooling function of the generator 47. It was set to 90%, which is smaller than that at the time.

  Similarly, when the outside air temperature T is 20 or more and less than 40 ° C., the DUTY value of each SSR 56, 57, 58 is 80%, and when the outside air temperature T is 40 or more and less than 60 ° C., each SSR 56, 57, When the DUTY value of 58 is 70% and the outside air temperature T is 60 or more, the DUTY values of the SSRs 56, 57, and 58 are set to 60%.

Therefore, for example, when it is determined in step 21 that the outside air temperature T is 30 ° C., the heater controller 50 sets the duty values of SSRs 56, 57, and 58 to 80% based on the output setting table shown in FIG. Set to. Thereby, the output of each electric heater 40, 41, 42 becomes 80% output, and each screed plate 30, 31, 32 is heated to the set heating temperature (T ₀ ) by each electric heater 40, 41, 42.

  Even if the outside air temperature T is another temperature, the heater controller 50 sets the duty values of the SSRs 56, 57, and 58 corresponding to the outside air temperature T based on the output setting table shown in FIG. The output of each electric heater 40, 41, 42 is an output corresponding to the duty value of SSRs 56, 57, 58.

The correlation between the outside air temperature T and the duty value shown in FIG. 8 is determined in consideration of the self-cooling function of the generator 47. Therefore, by setting the duty values of the SSRs 56, 57, and 58 based on the outside air temperature T and the output setting table shown in FIG. 8 and performing the output control of the electric heaters 40, 41, and 42, each screed plate 30, 31 and 32 can be heated to the set heating temperature T _0, and it is possible to prevent the generator 47 from exceeding the power generation limit and the life of the generator 47 from being reduced.

  Furthermore, in the present embodiment, the outside air temperature serving as the threshold value is set more finely than the preparation mode processing described with reference to FIGS. 5 and 7, and thus a more accurate preparation mode corresponding to the outside air temperature T is set. Time processing can be performed. Therefore, according to the process in the preparation mode according to the present embodiment, the screed plates 30, 31, and 32 can be heated in an optimal state without excess or deficiency, and highly efficient heat treatment can be performed.

  When the process of step 22 is completed, the process proceeds to step 23. Steps 23 to 25 are the same as steps 15 to 17 shown in FIG.

  That is, in step 23, the heater controller 50 determines whether or not the temperature of each screed plate 30, 31, 32 has reached the set heating temperature (120 ° C.), and determines that the heater has been heated to the set heating temperature (YES determination). Then, the process proceeds to step 24, and the appropriate temperature indicator lamp 64 provided in the operation unit 27 is turned on.

  In the following step 24, it is determined whether or not the mode changeover switch 60 is maintaining the preparation mode. If it is determined that the preparation mode is maintained (in the case of YES determination), the process returns to step 21; When the mode switch 60 is switched from the preparation mode, the preparation mode processing shown in FIG. 6 ends.

By performing the above-described processing in the preparation mode of each of the cylinders 10 and 20, the screed plates 30, 31, and 32 are heated to the set heating temperature T ₀ and the pavement processing by the screed device 24 becomes possible. As described above, when it is possible to also continue the preparation mode after each screed plate 30, 31 and 32 are heated to set the heating temperature T _0, usually ready mode ends, the operator of the asphalt finisher 10 Operates the mode changeover switch 60 to switch to the construction mode.

  The process in the construction mode that is performed in the construction mode is a process that is performed in order to keep the temperature of the screed plates 30, 31, and 32 at the set heating temperature (120 ° C.). This construction mode process can be implemented using, for example, a feedback control process.

  That is, the heater controller 50 is configured to detect the temperature of each screed plate 30, 31, 32 from the output of the heating temperature sensors 37, 38, 39, and this detected temperature is increased or decreased by a predetermined temperature with respect to the set heating temperature. At this time, the heater temperature adjusting device 55 may be controlled to drive or stop the electric heaters 40, 41, 42.

  The process in the construction mode is not limited to the feedback control process described above, and other control methods for keeping other temperatures constant may be employed.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments described above, and various modifications are possible within the scope of the gist of the present invention described in the claims. It can be modified and changed.

DESCRIPTION OF SYMBOLS 10 Asphalt finisher 20 Traveling body part 21 Hopper 22 Conveyor 23 Screw spreader 24 Screed device 27 Operation part 30 Front screed plate 31 Left screed plate 32 Right screed plate 37-39 Heating temperature sensor 40-42 Electric heater 43 Engine 44 Hydraulic pump 45 Electromagnetic Proportional valve 46 Hydraulic motor 47 Generator 50 Heater control controller 51 Traveling body control controller 52 Conveyor control controller 55 Heater temperature adjustment device 56 Front heater SSR
57 SSR for left heater
58 SSR for right heater
60 Mode selector switch 64 Temperature indicator 70 Outside temperature sensor

Claims (5)

A screed device for heating the screed plate with an electric heater;
A generator for generating electric power to be supplied to the electric heater;
A power amount setting device for setting a power amount to be supplied from the generator to the electric heater;
An outside temperature sensor for measuring the outside temperature;
A control device that controls the power amount setting device based on the outside air temperature detected by the outside air temperature sensor, and varies the amount of power supplied to the electric heater in accordance with the outside air temperature;
An asphalt finisher characterized by comprising:   The asphalt finisher according to claim 1, wherein the power amount setting device and the control device perform chopper control of power supplied from the generator to the electric heater. A screed temperature sensor for measuring the temperature of the screed plate and an indicator lamp are provided,
3. The asphalt finisher according to claim 1, wherein the control device turns on the indicator lamp when the temperature of the screed plate reaches a predetermined set heating temperature based on an output of the screed temperature sensor. 4. .   The said control apparatus controls the said electric energy setting apparatus so that the electric energy supplied to the said electric heater may become small with the raise of the said outside temperature, The Claim 1 thru | or 3 characterized by the above-mentioned. Asphalt finisher.   The asphalt finisher according to any one of claims 1 to 4, wherein the control device includes a table indicating a relationship between the outside air temperature and a control value of the electric heater.

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