JPS6251872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering device for a self-propelled portal crane equipped with rubber tire wheels that travels on a trackless road.

Conventionally, self-propelled gate-type cranes that run on roads, which are known for transporting containers at sea, are
As shown in the figures and FIG. 2, unlike ordinary automobiles, the tread is considerably larger than the wheel base, so the difference in rotational speed and steering angle between the inner and outer wheels becomes extremely large when driving around a curve. Therefore, if the steering angle between the inner and outer wheels is set to a proper relationship and the rotational speed difference is not adjusted to match this steering angle, the rubber tire wheels will be seriously damaged.

On the other hand, space between the wheels (between the front wheels and between the rear wheels) is required for cargo handling, so the power for driving is provided by an engine that drives the rubber tire wheels with a propulsion shaft, but in general, each wheel It relies on a hydraulic motor attached to the Furthermore, when driving around curves, the steering of the rubber tire wheels is generally done by hydraulic power steering. For this reason, it requires a hydraulic circuit, the equipment and piping that make up the hydraulic circuit, and has the drawbacks of not only a complicated structure but also poor efficiency. Furthermore, in cranes that transport heavy objects such as steel materials, a plurality of rubber tire wheels are provided at the bottom of each leg at the four corners of the crane, but in this case, due to the limitations of the travel path, they are generally arranged in tandem in the travel direction. When running on a curve, it is necessary to steer each rubber tire wheel along the curve, so it may be possible to do this by using the difference in rotation speed between the inner and outer wheels. It is better to forcibly steer both the front and rear wheels, and for this reason, if a hydraulic cylinder is placed on each rubber tire wheel, complicated control is required, which has the disadvantage of being expensive and difficult to maintain and repair. .

Therefore, the present invention was developed in view of the above points, and the steering when traveling on a curve is given from a steering controller on a steering wheel, and the electric cylinder is stroked at an appropriate speed via a variable voltage variable frequency controller. A detector detects the actual steering angle when the vehicle is running, and the rotation speeds of the inner and outer wheels are corrected to match the actual steering angle when the vehicle is running.
That is, the operating speed of each electric cylinder when traveling on a curve must be set appropriately depending on the traveling speed and traveling resistance of the vehicle, but this is difficult in practice and is therefore done through repeated trials. For this reason,
Once the vehicle is steered to a given angle, correction steering is performed to compensate for the difference from the actual angle, and the vehicle travels. Therefore, in order to prevent wear of the rubber tire wheels, the rotation ratio of the inner and outer wheels at each point must match the actual steering angle.

Accordingly, a first invention provides a steering device for a gate-type crane that is capable of traveling on roads by providing rubber tire wheels at the lower parts of each of the legs at the four corners of the crane. Electric cylinders for steering are arranged to engage with rubber tire wheels at the bottom of each of the legs at the four corners, and each of the electric cylinders is connected to an appropriate outer wheel steering angle corresponding to an inner wheel steering angle preset based on steering information of the steering handle. It commands and controls the steering angle so that the steering angle is the same, detects the actual stroke of the electric cylinder, and compares it with the command value from the steering wheel to correct the steering angle. Based on the detected information of the actual stroke, the left and right A second invention is characterized in that a variable voltage variable frequency controller of an induction motor for traveling drive is controlled to a preset appropriate inner ring rotation speed ratio, and a second invention is the gantry crane of the first invention, wherein the rubber tire wheels are Both ends of the equalizer disposed in the traveling direction on each leg are horizontally rotatable and supported by a yoke, and both yokes are connected with a rod at a lever ratio that allows the two rubber tire wheels to have an appropriate relationship angle when traveling on a curve. The electric cylinder, which is pivotally supported on the vehicle body, is connected to the yoke of the vehicle.

The purpose of this is to simplify the mechanism and obtain a highly efficient steering system for a gate type crane vehicle by using electric power to drive and steer the rubber tire wheels, as well as to obtain a steering system suitable for transporting heavy objects. There is a particular thing.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

Figures 1 and 2 are a front view and a side view showing the entire road-driving gate type crane, and Figures 3 to 5 are a front view, side view, and plan view showing details of the steering device, and Figures 3 to 5 are front views, side views, and plan views showing details of the steering device. Figure 6 is an explanatory diagram showing the state when traveling on a curve, Figure 7 is an explanatory diagram of the control of the steering device, and Figure 8 is an explanatory diagram showing the state when traveling on a curve.
The figure shows the relationship between the steering angle and rotational speed ratio of the inner and outer wheels when traveling on a curve.

The road-driving gate type crane has four crane legs 2a, 2b, 2c, and 2d suspended at the four corners of the girder 1.
Two rubber tire wheels 3a, 3 are attached to the lower end of this.
b, and a transverse truck 4 is provided on the girder 1, on which a spreader 5 is suspended, and the cargo 7 is hoisted up by a hook 6 provided on the spreader 5 and transported to the destination.

Power for traveling and lifting and moving cargo is provided by a diesel generator, and power unit 8
crane legs 2 arranged in the running direction as
It is mounted on a frame 9 that connects crane legs 2b and 2b, and is operated in a driver's cab 10 to move the traversing trolley 4, lift cargo, etc., and drive the traveling drive provided on the crane legs 2b and 2d. rubber tire wheels 3b and electric cylinders 11a, 11 for steering provided on each crane leg 2a to 2d.
Induction motor 1 that operates b, 11c, 11d
2a and 12b.

Rubber tire wheels 3a and 3b are provided on each of the four crane legs 2a to 2d and supported by yokes 14a and 14b via an equalizer 13.

Each crane leg 2a to 2d has a rubber tire wheel 3.
Since a and 3b are attached by almost the same means, the third
Taking as an example the case where the equalizer 13 is attached to the lower part of the crane leg 2b in FIGS.
6, the equalizer 13 rotatably supports vertical shafts 17a, 17b fixed to the upper portions of the yokes 14, 14a, 14b, and the equalizer 13 rotatably supports the yokes 14a, 14b, respectively. It supports provided rubber tire wheels 3a, 3b.

The induction motors 12a and 12b are provided on a yoke 14b provided at the lower part of the crane legs 2b and 2d arranged on the left and right sides of the traveling direction. Add this to crane leg 2b
The case will be explained with reference to Figs. 3 to 5.
The induction motor 12a is mounted on a bracket 18 fixed to a yoke 14b, and its driving force is provided by a chain 22 suspended between a sprocket 19 provided on the motor 12a and a sprocket 21 provided on an axle 20 of a rubber tire wheel 3b. is transmitted,
The wheel 3b is rotated to run the portal crane.

Each yoke 14a, 14b has an arm formed in the direction toward the outside of the crane, and is connected by a rod 23. For example, in FIGS. 3 to 5, arms 24 and 25 are fixed to the yokes 14a and 14b, and both ends of the rod 23 are pivotally supported by the arms 24 and 25.

Electric cylinders 11a, 11b, 11c, 11d
connects the equalizer 13 provided at the lower part of each crane leg 2a to 2d and the yoke 14b. To explain this with reference to FIGS. 3 to 5 in the case of the electric cylinder 11b, the equalizer 1
An arm 26 is provided on the yoke 14a side of No. 3 so as to protrude toward the inside of the crane.
The head side of the electric cylinder 1b is pivotally supported by a pin 27, and the rod 28 of the electric cylinder 11b is pivotally supported by a pin 30 to an arm 29 which is fixedly attached to the yoke 14b and protrudes toward the inside of the crane.

Therefore, when the electric cylinders 11a to 11d operate, the cylinder rod 28 expands and contracts, and the rubber tire wheels 3a and 3b are steered. For example, when the cylinder rod 28 is extended, the arm 29 rotates about the vertical axis 17b, steering the rubber tire wheel 3b, and the rod 23 pushes the arm 24, thereby steering the rubber tire wheel 3a. In this case _{, the} arms 24,2
The lengths l ₁ and l ₂ of 5 are set in the relationship l ₁ /l ₂ ≒Θ ₁ /Θ ₂ .

Next, the control and operation of the steering device configured as described above will be explained with reference to FIGS. 6 to 8.

The induction motors 12a and 12b for driving are driven by the power unit 8 at 200 volts and 60 cycles through variable voltage variable frequency controllers INV ₁ and INV ₂ , and similarly the electric cylinders 11a to 11d for steering are driven by induction motors 11a to 11d. Drive of the motor is provided via variable voltage variable frequency controllers INV ₃ , INV ₄ .

This variable voltage variable frequency controller INV ₁ to INV ₄
has a built-in converter and inverter,
The rotational speed of the induction motor is controlled by changing the voltage and frequency according to commands from a steering controller 31 on a steering wheel in the driver's cab 10 via a control unit 32. The steering controller 31 outputs a signal with, for example, a voltage value proportional to the steering angle of the steering wheel. The control unit 32 receives a signal from the steering controller 31 and outputs a command value corresponding to the preset signal to the variable voltage variable frequency controllers _INV1 to _INV4 .

This command value is the variable voltage variable frequency controller.
It is given by the ratio of the rotation speeds of the induction motors 12a and 12b via INV ₁ and INV ₂ . For example, when l ₃ = 4320 mm, the command value is issued according to the relationship shown in Figure 8a, and Θ
When ₁ = 20°, the rotation speed of induction motor 12b is 100
Then, the rotation speed of the induction motor 12c is 43.

Also, the rubber tire wheel 3b on the induction motor 12b side
The ratio of the steering angle of the rubber tire wheel 3b on the induction motor 12a side is controlled according to the relationship shown in FIG. 8b, for example, when Θ ₁ =20°, Θ ₃ =8.6°. The electric cylinders 11b and 11d are connected to the induction motor 12 to the variable voltage variable frequency controllers INV ₃ and INV ₄ .
A command is given to stroke at an appropriate speed in response to the rotational speed control of the motors a and 12b. On the other hand, the electric cylinders 11b and 11d have cylinder rods 28.
Detectors 33a and 33b are provided to detect the amount of expansion and contraction, and this signal is sent to a comparator 34 provided in the control circuit of the variable voltage variable frequency controllers INV ₃ and INV ₄ .
c, 34d.

The comparators 34c and 34d compare the command value from the control unit 32 and send forward/reverse or stop signals to the variable voltage variable frequency controllers _INV3 , _INV4 .

Further, signals from the detectors 33a, 33b are sent to comparators 34a, 34b via a proportional device 35, and a variable voltage variable frequency controller is used to control the rotation speed ratio of the inner and outer rubber tire wheels 3b corresponding to the actual steering angle.
Command to INV ₁ and INV ₂ . FIG. 6 shows an example in which all of the electric cylinders 11a to 11d are activated, and the vehicle travels around a curve with an extremely small radius R.

Note that the electric cylinders 11a to 11d can be operated only on either the driven wheel side or the driving wheel side. For example, the left and right electric cylinders 11a, 11c (or 11b, 1
1d) is activated to drive around a curve.

As explained above, the steering device for the road-driving gate type crane of the present invention uses induction motors installed separately on the left and right to drive the rubber tire wheels, and electric cylinders for steering are placed on each leg at the four corners of the crane. , the left and right induction motors and the variable voltage variable frequency controllers INV ₁ to INV ₄ of each electric cylinder adjust the rotation speed of the inner and outer wheels to the appropriate speed based on the steering information from the steering wheel, and also control the steering of the outer wheel appropriately corresponding to the steering angle of the inner wheel. In addition, the actual stroke of the electric cylinder is detected and compared with the command value from the steering wheel to correct the rotation speed of the inner and outer wheels and the steering angle. The equipment can be arranged to provide an inexpensive and efficient device without requiring a complicated circuit.

In addition, both ends of the equalizer provided on each leg are horizontally rotatable, and the rubber tire wheels are supported by yokes, and both yokes are connected by rods at a lever ratio that makes the appropriate relationship angle when traveling on curves. Since the steering is done using an electric cylinder in a single wheel, it is possible to transport heavier cargo than before, and the load is evenly distributed to each rubber tire wheel.The components are simple and easy to repair and repair.
This is an excellent invention as inspection is easy.

[Brief explanation of the drawing]

The drawings show an embodiment of a traveling device for a road-traveling gantry crane according to the present invention, and FIG. 1 is a front view showing the entire road-travelling gantry crane, FIG. Fig. 5 shows details of the steering device, Fig. 3 is a front view, Fig. 4 is a partially sectional side view, Fig. 5 is a plan view, and Fig. 6 is an explanation showing the state when traveling on a curve. 7 are explanatory diagrams showing the control of the steering device, and FIG. 8 is a diagram showing the relationship between the steering angle and rotational speed ratio of the inner and outer wheels when traveling on a curve. 1 is a girder, 2a, 2b, 2c, 2d are crane legs, 3a, 3b are rubber tire wheels, 8 is a power unit, 9 is a frame, 11a, 11b, 11
c, 11d are electric cylinders, 12a, 12b are induction motors, 13 is an equalizer, 14a, 14b are yokes, 15 is a bracket, 17a, 17b are vertical shafts, 23 is a rod, 24, 25, 26, 29 are arms, 28 is the cylinder rod, 31 is the steering controller,
32 is a control unit, 33a and 33b are detectors,
34a, 34b are comparators, 35 is a proportional device, INV ₁
thru INV ₄ are variable voltage variable frequency controllers.

Claims (1)

[Scope of Claims] 1. In a steering device for a gate-type crane that is capable of traveling on roads by providing rubber tire wheels on each of the lower legs at the four corners of the crane, the rubber tire wheels are separately driven for running on the left and right sides by an induction motor, and the rubber tire wheels are driven separately on the left and right by an induction motor. Electric cylinders for steering the wheels are disposed in engagement with rubber tire wheels at the bottom of each of the legs at the four corners, and each of the electric cylinders is adapted to correspond to an inner wheel steering angle preset based on steering information from the steering handle. Commands and controls so that the outer wheel steering angle is appropriate,
The actual stroke of the electric cylinder is detected and compared with the command value from the steering wheel to correct the steering angle, and the variable voltage of the left and right travel drive induction motors is varied based on the detected information of the actual stroke. A steering device for a road-driving gate type crane, characterized by controlling a frequency controller to a preset appropriate inner ring rotation speed ratio. 2. A rubber tire wheel is provided at each of the lower legs at the four corners of the crane, and the rubber tire wheels are driven separately for left and right by an induction motor, and an electric cylinder for steering the rubber tire wheels is installed at the rubber tire wheel at the lower part of each of the legs at the four corners. In the gate-type crane, the rubber tire wheels are engaged with each other and are command-controlled so that each electric cylinder is set to an appropriate outer wheel steering angle corresponding to a preset inner wheel steering angle based on steering information from a steering handle. is horizontally rotatable and supported by a yoke at both ends of an equalizer disposed in the traveling direction, and both yokes are connected by a rod at a lever ratio that makes the two rubber tire wheels have an appropriate relationship angle when traveling on a curve, A steering device for a road-driving gate-type crane, which connects one yoke to the electric cylinder pivotally supported on the vehicle body.