JPS59140107A - Wheel suspension mechanism for unmanned car - Google Patents

Abstract

PURPOSE:To prevent an unmanned car from joggling, by supporting two driving wheels onto a chassis by using an elastic body and always keeping a proper driving wheel pressure, in an unmanned car in which at least two driving wheels and two idle wheels are installed and steering is performed by the difference of speeds between two driving wheels. CONSTITUTION:When a load is loaded onto a bed 11, a limit switch 14 is closed, and a controller 15 gives instruction to a hydraulic pressure generator 12, and the hydraulic pressure acts onto a hydraulic cylinder 7 through a solenoid valve 13, and then a piston 8 is lowered. Therefore, a plate body 8b is lowered to compress a spring 10, and the pressure applied onto a driving wheel 3 installed onto a supporting member 6 through a frame 4 increases uniformly. When the load is taken-out from the bed 11, the limit switch 14 is opened, and the controller 15 releases the solenoid valve 13. Therefore, the hydraulic pressure applied onto the piston 8 is eliminated, and the plate body 8b is pushed-up by the spring 10, and a proper pressure is applied onto the driving wheel 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a suspension mechanism for wheels of an unmanned vehicle.

Conventionally, two driving wheels and two or more idle wheels are provided.
In an unmanned vehicle that performs steering based on the speed difference between the drive wheels, the suspension method for the drive wheels and idle wheels of the unmanned vehicle is such that the drive wheels are directly fixed to the vehicle body, and the idle wheels are attached to the vehicle body with spring support. A similar structure is commonly used. In the case of the above structure, the pressure of the drive wheels must always exceed a certain set value in order to continue driving without slipping due to the size of the load, unevenness of the road surface, or when approaching a slope. This is because the entire load loaded on an unmanned vehicle is supported by the drive wheels and idle wheels, so if the spring constant of the idler springs is too large, the vehicle may be under no load, the road may be uneven, or the drive wheels may This is because the pressure of the wheels against the road surface becomes too small, causing the drive wheels to slip.

Therefore, the constant of the idle wheel suspension spring is determined so that the drive wheel pressure is always above the set value.

By doing this, the unmanned vehicle can run without slipping because the drive wheels are always under pressure that is above the limit that would cause slippage.

However, when using the conventional method as described above, the load carried by the idler wheel is determined by the spring setting and is constant regardless of whether there is a load, and all of the increased vehicle weight due to the load is supported by the drive wheels. has, so if the load becomes too large,
The load ratio of the idler wheel support is too small compared to the load ratio of the drive wheel support. For this reason, when the load increases, the unmanned vehicle driver section will sway back and forth around the lower part of the drive wheels as the unmanned vehicle moves, and will also sway due to slight irregularities on the road surface when the unmanned vehicle is running, and will also shake when the unmanned vehicle suddenly stops. There is a tremor. This shaking becomes larger as the load becomes larger. Because of this shaking, if the unmanned vehicle is loaded with a tall load, the front of the load may change shape, or the front may fall off the unmanned vehicle. In addition, when loading the load of an unmanned vehicle onto a transfer table or conveyor, etc., the L side 1 novel of the unmanned vehicle changes centering around the lower part of the driving wheels of the unmanned vehicle, so the load of the unmanned vehicle must be transferred manually. In addition, when the front is transferred automatically, the front hits the front of the transfer table etc., resulting in unreliable problems. The purpose of this invention is to make the two drive wheels of an unmanned vehicle spring-supported, fix the idler wheels to the vehicle body, and change the pressure of the drive wheels depending on the weight of the load loaded on the unmanned vehicle, so that the drive wheels are always properly adjusted. By maintaining the pressure, the vibration of the unmanned vehicle can be maintained both when the unmanned vehicle is running, when it is stopped, and when the unmanned vehicle is stopped, thereby eliminating the drawbacks of the prior art.

The present invention will be described in detail below based on the drawings.

FIG. 1 is a wheel arrangement diagram of an unmanned vehicle according to the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. In FIGS. 1 and 2, reference numeral 1 indicates idle wheels, and two or more wheels are fixed to the front and rear portions of the lower portion of the vehicle body 2 of the unmanned vehicle in a 1μ contact. Reference numeral 3 denotes drive wheels, which are arranged independently at a location near the center of the lower part of the vehicle body 2 in unison, and are driven by a motor (not shown) attached to the frame 4, and due to the speed difference between these motors, the Steering an unmanned car. Two sets of five outer cylinders are attached to the support member 6 attached to the upper surface of the frame 4 and attached to the bottom of the vehicle body 2 in accordance with the arrangement of the drive wheels 3. Reference numeral 7 denotes a hydraulic cylinder, which has a piston 8 inside, and is located in a position where the shaft 8a of the piston 8 can be passed through a hole 9 drilled in the center of the outer cylinder 5 at the bottom of the vehicle body 2. They are installed at two locations inside the vehicle body 2. Reference numeral 1o denotes a spring, which is housed in the outer cylinder 6, and has one end fixed to the support member 6 and the other end fixed to the end of the shaft 8a of the piston 8.
It is joined to b. Note that this spring 8 pushes up the plate 8b when there is no load on the loading platform 11 of the unmanned vehicle,
It also has a spring constant that allows suitable pressure to be applied to the drive wheels 3. Reference numeral 12 denotes a hydraulic pressure generator, which is installed inside the vehicle body 2, and a solenoid valve 13 installed inside the vehicle body 2.
It is connected to the hydraulic cylinder 7 via. ] 4 is a limit switch, which is installed at one location near the center of the loading platform so as to close the limit switch when a load is placed on the loading platform. 1
A controller 5 performs general control of the unmanned vehicle. A battery 16 is a power source for the unmanned vehicle.

In the above configuration, when there is no load on the loading platform 11, the spring 1
If the restoring force of 0 pushes up the plate 8b and applies appropriate pressure to the drive wheels 3, the vehicle will run stably and without any problems if it is on a passage with constant road surface conditions.

When a load is placed on the loading platform 11vc, the limit switch 14 closes due to the weight in front of it, and the controller 15 detects this and gives an instruction to the hydraulic pressure generator 12, which generates hydraulic pressure and switches the open electromagnetic This oil pressure equally acts on two oil pressure cylinders 7 through the valve 13, and the piston 8 moves against the restoring force of the spring IO to a position where the spring 1o and the above oil pressure are in equilibrium.

Along with this, the plate 8b moves downward and the spring 10 is compressed. Therefore, the pressure applied to each drive wheel 3 increases equally. Note that the amount of movement of the piston 8 is determined by the relationship between the previous weight and the spring constant of the spring 10.
0 is determined so that an appropriate pressure can be applied to the drive wheel 3.

The seven electromagnetic valves 13 that apply appropriate pressure to the drive wheels 3 are closed, and the operation of the hydraulic pressure generator 12 is stopped. However, since the electromagnetic valve 13 is closed, a constant pressure is always applied to the drive wheel 3.

Next, when the load on the loading platform 11 is gone, the limit switch 1
4 opens, the controller 5 detects this, gives an instruction to the electromagnetic valve 3, and this electromagnetic valve 13 opens. When the electromagnetic valve 13 opens, the hydraulic pressure applied to the piston 8 disappears, and the restoring force of the spring 1° pushes up the plate 8b.
The pressure applied to the drive wheels 3 returns to its original state.

Note that the present invention is not limited to the above-mentioned embodiment, and for example, a plurality of limit switches may be used as necessary. Also, if there are various weights of loads to be loaded on the loading platform 11, the weight of the loads can be set in advance in the controller 15. or read the barcode, etc. indicating the weight that has been digitized by (-1) each time, input the weight of the load, or input the weight of the load from the ground side, and then input it from the controller 15 to the hydraulic pressure generator 12. A current is applied to the loading platform 11 according to the weight of the load on the loading platform 11, and the hydraulic pressure generator 12 is activated in proportion to this current.
may generate hydraulic pressure. Further, depending on the road surface condition, the load of the unmanned vehicle, and other circumstances, hydraulic pressure may not be used at all, and the pressure applied to the drive wheels by the spring may be kept constant.

As explained above, according to the present invention, the two drive wheels of the unmanned vehicle are supported by springs, the road width is fixed to the vehicle body, and the pressure of the drive wheels is varied depending on the weight of the load loaded on the unmanned vehicle, Since the drive wheel pressure is always maintained at an appropriate level, the unmanned vehicle no longer shakes even when its load increases, and even under adverse conditions such as uneven road surfaces (the unmanned vehicle no longer shakes and the unmanned vehicle This eliminates changes in the appearance of the load loaded onto the vehicle, improving the reliability of transporting goods without damaging the load.Furthermore, even if the center of gravity of the load loaded onto the unmanned vehicle is shifted from the center of the unmanned vehicle's body, The top surface level of the unmanned vehicle does not change when the unmanned vehicle is stopped, and the positional relationship with the other party's transfer equipment is maintained at a good level during the automatic transfer of the load. Reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a wheel arrangement diagram of an unmanned vehicle according to the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. 1... Road width 3... Drive wheel 10... Spring applicant Kami Denki Co., Ltd. agent Patent attorney Haruya Saito

Claims (1)

[Claims] In an unmanned vehicle that has two independent drive wheels in the central part of both sides of the vehicle, two or more idle wheels at the front and rear of the vehicle, and that steers based on the speed difference between the two drive wheels, the two drive wheels are connected to the drive wheel using an elastic body. A wheel suspension mechanism for an unmanned vehicle, which is supported on the vehicle body of the unmanned vehicle, and the idler wheels are fixedly supported directly to the vehicle body.