JPH0745610Y2 - Asphalt finisher speed adjustment device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a speed adjusting device for a wheel type asphalt finisher, and more particularly to a traveling device for adapting a front wheel speed to a rear wheel speed.

[Prior Art] Asphalt finishers are generally mainly composed of a vehicle body 19, a hopper 20, a front wheel 8, a rear wheel 5, a screed 21, a feeder 22 and a spreader as shown in FIG. 9 (side view) and FIG. 10 (front view). Composed of 23. During asphalt pavement construction, the hopper 20 receives the asphalt mix for paving from the dump truck while traveling with the front wheels 8 and the rear wheels 5.
The car body 19 is fed by the feeder 22 through the tunnel 30 in the car body 19.
After discharging to the rear part, the spreader 23 is spread on the front part of the screed 21 towed by the side arm 24 rotatably attached to the vehicle body 19 by the pivot pin 25. The screed 21 rides on the pavement asphalt mixture that has been spread to the front, determines the pavement thickness by its supporting force, and is pulled by the vehicle body 19 to move forward to continue the pavement work.

At this time, due to the structure of the asphalt finisher, the installation space for the front wheels 8 is arranged at the bottom of the hopper 20, so that the rear wheels 5
Therefore, the diameter of the front wheel 8 needs to be considerably smaller than that of the rear wheel 5 as compared with the installation space. Further, since the feeder 22 is installed inside the vehicle body 19, in the asphalt finisher driven by the front wheels 8 and the rear wheels 5, the left and right penetrating drive shafts of the front wheels 8, the differential gear, the motor, etc. are provided inside the vehicle body 19. In order to drive the front wheels 8, there is no choice but to install front wheel motors 6 for driving the front wheels 8 in the immediate vicinity of the left and right front wheels 8, respectively.

For this reason, the rear wheel motor 1 for driving the rear wheel 5 and the front wheel motor 6 of the front wheel 8 are placed separately, and the speeds of the front wheel 8 and the rear wheel 5 having different diameters are greatly different from each other to prevent slipping or idling during traveling. In order to synchronize (peripheral speed), it is necessary to make the rotational speeds of the two significantly different. This is because when the front wheels 8 and the rear wheels 5 are different in speed and slipping or slipping occurs, the traveling driving force cannot be generated uniformly, and the effect of improving the driving force of the front and rear wheels cannot be exhibited.

At this time, the front and rear wheel drive system in a normal asphalt finisher is hydraulically driven both front and rear wheels, as shown in FIG. 11, and the rear wheel 5 is driven by the hydraulic oil discharged from the pump 18 rotated by the drive source 26. From the driven rear wheel motor 1,
Power is transmitted through a transmission mechanism section 10 including a driving force distribution mechanism to generate a driving force. The front wheels 8 have left and right front wheel motors 6 driven by hydraulic oil discharged from the pump 12 rotating by the drive source 26 and divided into left and right wheels,
The front wheel 8 is rotated differently from the rear wheel 5 to synchronize the speed and generate a driving force.

In the conventional speed control system for the front wheels 8 and the rear wheels 5, as shown in FIG. 12, the rotational speeds of the front wheels 8 and the rear wheels 5 are greatly different from each other depending on the speed set by the speed setter 14. System without controlling the actual speed feedback, and controlling them simultaneously via the controller 15, or
As shown in the figure, only the rear wheel 5 is rotated at the rear wheel speed controller 17
With respect to the rotation of the front wheels 8, the controller 16 controls only the torque of the rotation of the front wheels 8 to a predetermined maximum value regardless of the set rotation speed and the actual rotation speed of the rear wheels 5.

[Problems to be solved by the device]

The above-mentioned conventional asphalt finisher has the following problems to be solved. That is, in the pavement construction by the asphalt finisher, as an element that determines the pavement finish state,
Ensuring flatness, ensuring compactness and uniformity, and finishing surface cleanliness. Particularly regarding the flatness, it is regarded as a particularly important factor to secure the flatness, which has a great influence on the riding comfort as the vehicle travels faster. If the flatness of the finished surface cannot be ensured, the pavement builder is forced to repair the existing pavement surface, resulting in an unnecessary increase in construction cost.

Further, the compactness is also required to be more uniform from the viewpoint of securing the supporting force of the pavement surface as the vehicle travels larger. This is because if the compaction degree is non-uniform, the supporting force will also be non-uniform, and the flexing state of the pavement surface due to passage of a large vehicle will change, affecting the stable running of the vehicle.

And, the basic requirement required for pavement construction in the asphalt finisher in order to secure the flatness and the uniformity of compaction degree is to keep the pavement speed constant during the pavement construction. This is because if the pavement speed changes during pavement construction, the screed, which is the pavement leveling part of the asphalt finisher, changes the compaction capacity of the pavement mix material per unit pavement distance, and the uniformity of the compaction cannot be maintained. At the same time, the bearing capacity of the paving mix for the screed, which is the leveling part of the asphalt finisher, also changes, resulting in a change in the pavement thickness, which makes it impossible to ensure flatness. This is because it will surely be a factor for missing the element to be performed.

As is clear from the above, keeping the pavement speed constant during pavement construction is an important basic requirement for determining the pavement finish condition in the asphalt finisher.

By the way, in a wheel type asphalt finisher in which both front and rear wheels are driven, synchronizing the speeds of the front and rear wheels having different rotational speeds is an important point as described in the section of the prior art. Further, when driving the wheel type asphalt finisher to the front and rear wheels, the rear wheels mainly exert the driving force from the load distribution of the front wheels and the rear wheels, and the front wheels supplementarily exert the driving force.

At this time, in the method in which the rotational speeds of the rear wheel and the front wheel, which are greatly different from each other, are simultaneously controlled by the speed setting device, the variation of the actual rotational speed with respect to the set rotational speed due to the load resistance of the rear wheel is ignored and the front wheel rotational speed is Since it is set, a speed difference between the front and rear wheels occurs and the two are out of synchronization with each other, which causes slipping or slipping.

Further, in the method of controlling only the front wheel torque, the front wheel rotation speed rises up to the rotation speed at which the set drive torque is generated regardless of the rear wheel speed, so depending on the front wheel load and the road surface friction coefficient, The front wheel rotation speed is too high and slippage or idling occurs. In addition, when starting and stopping, it immediately rises to the maximum torque or falls to zero torque, but normally small diameter solid tires are mounted on the front wheels and large diameter pneumatic tires are mounted on the rear wheels, and its deflection is Since they are different, a sudden change in the front wheel driving force at the time of starting and stopping causes a shock.

However, if slipping or slipping during paving, or shock when starting or stopping, the paving speed will fluctuate instantaneously. It becomes impossible to keep the speed constant, and it becomes impossible to secure the flatness, and at the same time, the uniformity of compaction cannot be maintained, and a satisfactory paving finish cannot be obtained. As a result, there has been a problem that the pavement builder needs to carry out the repair of the existing pavement surface and, at the same time, causes a loss of credibility.

[Means for Solving the Problems]

As a means for solving the above problems, the present invention provides a front wheel and a rear wheel each having a driving force by a hydraulic motor, a hydraulic oil adjusting means interposed upstream of a flow path of the hydraulic motor of the front wheel, and a peripheral speed of the rear wheel. A rear wheel speed sensor for detecting, and a front wheel speed control means for controlling the speed of the front wheel to match the speed of the rear wheel via the hydraulic oil adjusting means by the speed signal of the rear wheel detected by the speed sensor. It is intended to provide an asphalt finisher having a speed adjusting device characterized by the following.

[Action]

Since the present invention is constructed as described above, it has the following effects. That is, the actual speed of the rear wheels of the asphalt finisher is detected by the rear wheel speed sensor, and the signal is sent to the front wheel speed control means via the hydraulic oil adjusting means such as a flow rate adjusting valve, and the rear wheel speed is detected. Since the front wheel speed is controlled to match, the front wheel speed can be adapted to the rear wheel speed, and the optimum front wheel speed can be obtained without causing slippage during idling, starting or stopping during paving work. ,
It is possible to suppress fluctuations in pavement speed.

〔Example〕

A first embodiment of the present invention will be described with reference to FIG. The same components as those in FIGS. 9 to 13 of the conventional example are designated by the same reference numerals, and the description thereof will be omitted unless otherwise necessary.
The same applies to the second to sixth embodiments below.

In FIG. 1, a front and rear wheel traveling drive system basic system diagram of an asphalt finisher hydraulically driving two rear wheels 5 and two front wheels 8 is shown. The rear wheels 5 are discharged from a pump 18 rotated by a drive source 26. Power is transmitted from the rear wheel motor 1 driven by the hydraulic oil to generate a driving force via the transmission mechanism portion 10 including a differential mechanism. The left and right front wheel motors 6 which are driven by the hydraulic oil discharged from the pump 12 rotating by the drive source 26 and which are divided into left and right wheels are incorporated in the front wheels 8 to generate a driving force. At this time, the flow rates of the hydraulic oil flowing into the rear wheel motor 1 and the front wheel motor 6 are synchronized and synchronized as follows. That is, first, the speed control of the rear wheels 5 is performed by the rear wheel speed controller 17 controlling the number of rotations of the rear wheel motor 1. A rotation speed sensor 2 is installed on the rear wheel motor 1, and the rear wheel 5 is detected by detecting the output rotation speed of the hydraulic transmission.
To detect the actual speed of. The output signal 3 of the rotation speed sensor 2 is sent to the front wheel speed controller 4 to determine the rotation speed of the front wheel motor 6 based on the actual speed of the rear wheels 5. At this time, as shown in FIG. 7, the determined number of revolutions corresponds to the increase of the actual speed of the rear wheels at the time of starting, as shown in FIG. At the same time as controlling so as not to become faster than the actual speed increase state, at the end,
Raise the vehicle with a time lag to the front wheel speed that matches the actual speed of the rear wheel. In order to prevent slippage between the front wheels and the road surface due to the front wheel speed being lower than the rear wheel speed at the time of starting, the front wheel speed is assisted by the rear wheel driving force. In order to be able to follow the above, a hydraulic or mechanical means for compensating for the shortage of the front wheel rotational speed by idling is provided in the front wheel drive mechanism by the front wheel motor. The front wheels 8 immediately when stopped
The control is performed so as to reduce the speed of the front wheels 8 in accordance with the actual speed reduction state of the rear wheels 5 instead of reducing the driving force of the. The flow rate adjusting valve 7 is operated by the output signal of the front wheel speed controller 4 thus determined. Therefore, the flow rate adjusting valve 7
The hydraulic oil flow rate that has passed through is equal to the flow rate that optimally rotates the front wheel motor 6. As a result, this hydraulic oil causes the front wheel motor 6 to rotate at an optimum rotation speed corresponding to the actual speed of the rear wheel 5, and the front wheel 8 is rotated at the output rotation speed of the front wheel motor 6 to obtain the optimum speed of the front wheel 8. Can be done. As a sensor for the output speed of the hydraulic transmission, instead of the rotation sensor 2 of the rear wheel motor 1, a rear wheel speed sensor 9 as in the second embodiment shown in FIG. 2 or a third embodiment shown in FIG. As in the example, a speed sensor 11 of the transmission mechanism 10 between the rear wheel motor 1 and the rear wheel 5, a sensor of the rear wheel speed itself, or a hydraulic oil flow sensor for driving the rear wheel motor 1 may be used. . The rear wheel rotation speed sensor 9 in the second embodiment of FIG. 2 detects the rotation speed of the rear wheel 5 on one side and uses the output 3 as a representative value as shown in FIG. It is also possible to attach the rear wheel rotation speed sensor 9 to each of them and use the calculated value such as the average value of the output values of both as the input value of the front wheel speed controller 4. Further, as in the fourth embodiment shown in FIG. 4, in the asphalt finisher of the type in which the driving force of the rear wheels 5 is obtained by mechanically transmitting the rotation of the drive source 26, the rear wheel actual speed sensor is used. It is also possible to use a speed sensor 28 in the transmission mechanism 27 between the drive source 26 and the rear wheel 5, or a rotation speed sensor of the drive source 26 or a speed or rotation speed sensor of the rear wheel 5 not shown in the figure. Is.

The flow rate control to the front wheel motor 6 is replaced with the flow rate adjustment valve 7 only, instead of the method of controlling the discharge amount of the pump 12 for driving the front wheel motor 6 or the flow rate adjustment as in the fifth embodiment shown in FIG. Control by the combined adjusting device 13 for adjusting the valve and pump discharge amount or a flow rate adjusting method other than these is also possible. In addition, the method of distributing the hydraulic fluid discharged by the pump 12 for the front wheels 8 by the left and right front wheel motors 6 is to secure the driving force when one front wheel is lifted up due to the influence of road surface irregularities etc. Therefore, it is possible to temporarily or continuously define the both-side front wheel rotation speed ratio by using a shunt valve in order to have a differential lock effect.

Further, the pump 12 that drives the front wheel motor 6 may be a pump dedicated to the front wheel motor, or may be a system that also serves as another drive and divides and extracts the working oil for the front wheel motor.

In the case where the rear wheels 5 are driven by the two rear wheel motors 31 according to the left and right, as in the sixth embodiment shown in FIG. 6, the calculator of the output of the rotation speed sensors 2 of both the rear wheel motors 31. The calculated value such as the average value by 29, the calculated value such as the average value of the outputs of the rotation speed sensors of both the rear wheels 5 not shown in the figure, or the one side rear wheel motor 31 or the one side rear wheel 5 rotation speed sensor It is possible to use the output value of the above as a representative value and input it to the front wheel speed controller 4.

Further, in an asphalt finisher in which the rear wheel speed reduction state can be arbitrarily set when stopped, the rear wheel speed reduction at the time of stop is slightly delayed, and the rear wheel stop instruction signal is also sent to the front wheel speed controller 4 As shown in FIG. 8, the front wheel control speed is reduced prior to the reduction state of the rear wheel speed by further inputting into the input, and it is possible to further enhance the effect of preventing the shock at the time of stop. At this time, the delay time for lowering the rear wheel speed is set to a time that has no problem in pavement construction and safety. Further, the difference in speed between the front and rear wheels at this time is compensated by the apparent slippage of the front wheels 8 as in the case of starting. However, in reality, the rear wheel 5 is followed by being pushed. Even when the rear wheel speed reduction state cannot be arbitrarily set, the same front wheel speed reduction time control as described above can be performed if a certain rear wheel speed reduction time delay can be expected when the vehicle is stopped.

In addition, the maximum driving force that can be generated by the front wheels 8 also fluctuates in response to changes in the load on the front wheels 8 due to an increase or decrease in the loading amount of asphalt mix material for paving in the hopper 20, so this system has a control function for the front wheel driving torque. It is also possible to add.

Further, other uniaxial two-wheel idle rear wheels can be added to the rear wheels 5, and other uniaxial two-wheel idle front wheels can be added to the front wheels 8.

As described above, according to the first to sixth embodiments, the speed sensor or the rotation speed sensor directly or indirectly detects the speed (peripheral speed) of the rear wheel, and sends the signal to the front wheel speed controller to send the signal to the front wheel. Since the speed of the asphalt can be controlled to the optimum speed to adapt to the speed of the rear wheels, the speed at which the asphalt finisher starts and stops during paving work, that is, the speed at which the asphalt finisher progresses, that is, the pavement speed, can be maintained in an optimum state, and the pavement flatness and tightening The uniformity of hardness can be achieved.

[Advantages of the Invention] Since the present invention is configured as described above, it has the following effects. That is, since the optimum front wheel speed synchronized with the rear wheel speed is obtained, the rear wheel having the driving force is not influenced by the front wheel speed having the same driving force, and therefore only the speed control of the rear wheel is centrally performed. Since the speed of the asphalt finisher can be maintained arbitrarily, stable pavement speed, which is the most important requirement when paving, is obtained, and pavement flatness and compactness uniformity are achieved.

[Brief description of drawings]

FIG. 1 is a front and rear wheel drive system diagram as one embodiment of the present invention, FIG. 2 is a system diagram of an example using a rear wheel rotation speed sensor which is a second embodiment of the present invention, and FIG. 3 is the present invention. FIG. 4 is a system diagram of an example using a speed sensor of a transmission mechanism part, which is a third embodiment of the present invention, and FIG. 4 is obtained by mechanically transmitting a driving force of a rear wheel which is a fourth embodiment of the present invention from a drive source. System diagram showing an example of application of the method to asphalt finishers,
FIG. 5 is a system diagram of a control example by a combination of a flow rate control valve and pump discharge amount adjustment according to a fifth embodiment of the present invention, and FIG. 6 is a sixth embodiment of the present invention with two rear wheels. FIG. 7 is a system diagram showing an example of application to a left and right asphalt finisher driven by a wheel motor, and FIG. 7 shows a control state of a front wheel control speed corresponding to a rear wheel actual speed detected in an embodiment of the present invention. FIG. 8 is a view showing a front wheel speed control state at a stop in another embodiment of the present invention, FIG. 9 is a side view of a conventional asphalt finisher, and FIG. 10 is a side view of the asphalt finisher of FIG. Front view, FIG. 11 is a basic system diagram of front and rear wheel drive system in a conventional asphalt finisher, and FIG. 12 is a system diagram of a method of simultaneously controlling the rotational speeds of front wheels and rear wheels of an example of a conventional example. , Fig. 13 shows a conventional example It is a system diagram of a method to control only the front wheel torque of another example. 2 ... Rotation speed sensor, 3 ... Output signal, 4 ... Front wheel speed controller, 5 ... Rear wheel, 7 ... Flow control valve, 8 ... Front wheel,
9 …… rear wheel rotation speed sensor, 11 …… speed sensor, 12 …… pump, 13 …… compound adjusting device, 28 …… speed sensor, 29 ……
Calculator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Fujiwara 1-3-2 Kita-Aoyama, Minato-ku, Tokyo New Caterpillar Mitsubishi Corporation (72) Takafumi Fujimoto 1-3-2 Kita-Aoyama, Minato-ku, Tokyo New Caterpillar Mitsubishi Corp. (56) Reference JP 50-103029 (JP, A) JP 61-157438 (JP, A) JP 63-137026 (JP, A) Actual 63- 101226 (JP, U) Actual development Sho 59-188730 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A front wheel and a rear wheel each having a driving force by a hydraulic motor, a hydraulic oil adjusting means interposed upstream of a flow path of the hydraulic motor of the front wheel, and a rear wheel speed for detecting a peripheral speed of the rear wheel. And a front wheel speed control means for controlling the speed of the front wheel to match the speed of the rear wheel via the hydraulic oil adjusting means by a speed signal of the rear wheel detected by the speed sensor. Asphalt finisher with a speed control device.