JPH0872614A - Step elevating device of cab over type car - Google Patents

Abstract

PURPOSE: To eliminate the need of reversing operation of an electric motor for generating oil pressure by providing on control circuit for controlling first opening and closing solenoid valve and switching solenoid valve and second opening and closing solenoid valve and switching solenoid valve according to the operation input. CONSTITUTION: Oil pressure is supplied to a first hydraulic circuit 10 and a second hydraulic circuit 20 in common by one hydraulic pump 4. The supply control for the oil pressure is conducted according to the operation input, so that in the first hydraulic circuit 10, the first opening and closing solenoid valve 11 opens and closes an oil pressure path to a first cylinder, and the first switching solenoid valve 12 switches the oil pressure supply direction of the first cylinder 1. In the second hydraulic circuit 20, the second opening and closing solenoid valve 21 opens and closes an oil pressure path to a second cylinder 3, and the second switching solenoid valve 22 switches the oil pressure supply direction to the second cylinder 3. These four solenoid valves 11, 12 and 21, 22 are controlled by one control circuit 6. Thus, the need of reversing operation of an electric motor 5 for generating oil pressure can be eliminated so as to reduce the manufacturing cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to control steps provided for getting on and off a cab-over vehicle. INDUSTRIAL APPLICABILITY The present invention is used in a cab-over type automobile that cabs for maintenance.

[0002]

2. Description of the Related Art In recent years, as cab-over type automobiles for freight and other vehicles have grown in size and the number of female drivers driving cab-over type automobiles has increased, a step for getting on and off outside a cab Vehicles equipped with have become popular. If this step for getting on and off is installed in a convenient position for getting on and off, the step will project to a position lower than the chassis height of the vehicle,
It is inconvenient for driving a car. Therefore, a device for displacing this step for getting on and off using an actuator has been developed and used (for example, Japanese Utility Model Publication No. 2-37643).

The conventional example device is provided with a step for getting on and off a cab-over vehicle so that the cab can be stored in conjunction with the cab when it is tilted.
No. 4), and a structure that interlocks with the door for getting on and off the driver's seat (Japanese Utility Model Publication No. 2-15716).

In these conventional structures, whether the actuator for driving the boarding / alighting step is an electric type or a hydraulically driven actuator, a unique device is provided for driving the boarding / alighting step. I have it. Even with a drive device for changing the position of a boarding / alighting step, if safety and reliability of the device are taken into consideration, it is possible to drive effectively even when a load of several times the weight of a person is applied. There is a problem that the device is considerably expensive regardless of whether the hydraulic circuit or the electric circuit is used, and the number of parts to be mounted on the vehicle is large and the vehicle weight is increased. .

In a prior application (Japanese Patent Application No. 6-75076, not yet published at the time of filing of this application) in which the applicant of the present application is one of the joint applicants, a new device for controlling the step for getting on and off using hydraulic pressure for cavitating is proposed. Proposed. This is characterized in that a switching valve for switching the output hydraulic pressure of the hydraulic pressure generator for the cavit to the hydraulic circuit for step displacement is provided.

[0006]

The inventors of the present application have conducted many tests on the technique disclosed in this prior application. As a result, it was confirmed that the hydraulic pressure generator for the cavit can be effectively used for the hydraulic pressure for the step displacement, but the electric motor for hydraulic pressure generation that requires a large number of parts for the switching control of the hydraulic circuit. Forward / reverse control is required for the vehicle, insufficient measures are taken against power failure in the control circuit, etc. It was inconvenient, and some improvements were discovered.

The present invention has been made against such a background, and an object thereof is to provide an inexpensive hydraulic circuit.
The present invention aims at simplifying the hydraulic circuit for step raising and lowering. SUMMARY OF THE INVENTION It is an object of the present invention to provide a step lifting device that does not require reverse rotation of a hydraulic pressure generating motor. An object of the present invention is to provide a hydraulic step lift device at low cost. It is an object of the present invention to provide a step lifting device that is controlled on the safe side even when the power supply of the control circuit is stopped. It is an object of the present invention to provide a device that allows a driver to appropriately operate a step lifting device even when trying to get on a vehicle.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for raising and lowering steps provided for getting on and off a cabover vehicle, which comprises a first hydraulic circuit for supplying a hydraulic pressure to a first cylinder for a cabot. A second hydraulic circuit that supplies hydraulic pressure to a second cylinder that moves up and down the steps provided at the entrance and exit ports; and a hydraulic pump that commonly supplies hydraulic pressure to the first hydraulic circuit and the second hydraulic circuit. The one hydraulic circuit includes a first opening / closing solenoid valve for opening / closing a hydraulic passage between the first cylinder and the first switching solenoid valve for switching the hydraulic pressure supply direction of the first cylinder, and the second hydraulic circuit is provided. A second opening / closing solenoid valve for opening / closing a hydraulic passage between the second cylinder and the second cylinder, and a second switching solenoid valve for switching the hydraulic pressure supply direction of the second cylinder. Characterized by comprising a single control circuit Gosuru.

The first opening / closing solenoid valve and the second opening / closing solenoid valve cut off the hydraulic passage in the excited state (on state) and connect the hydraulic passage in the non-excited state (off state), respectively. The valve supplies hydraulic pressure in a direction to tilt the cab in the excited state and hydraulic pressure in a direction to return the cab in the non-excited state, and the second switching solenoid valve supplies hydraulic pressure in a direction to lower the step in the excited state and does not It is desirable to supply the hydraulic pressure in the direction of increasing the step in the excited state.

The operation inputs are a tilt / step changeover switch which is manually operated, a tilt up / down instruction switch which is manually operated, a load switch which is operated by a load on the step, an upper limit switch of the step and A lower limit switch, wherein the control circuit controls the first opening / closing solenoid valve and the second opening / closing solenoid valve according to the setting position of the tilt / step changeover switch, and sets the tilt up / down instruction switch. Means for controlling the first switching solenoid valve according to the position, means for controlling the second switching solenoid valve according to the setting position of the load switch and the setting states of the two limit switches, and the key switch of the vehicle is turned off. Means for prohibiting all exciting currents supplied to the four solenoid valves when in the state Mukoto is desirable.

Further, the control circuit is provided with a key for generating a radio wave signal, and means for receiving the radio wave signal in the control circuit and the second opening / closing electromagnetic field unless a specific signal arrives at the receiving means. Means for putting the valve into a hydraulic pressure cutoff state, the operation input includes an opening sensor output of the door for which the step is provided, and the control circuit uses the opening sensor to allow a person to get on or off the door. It is desirable to include means for activating the second hydraulic circuit only when it is as open as possible.

[0012]

When the control circuit receives an operation input, the hydraulic pump is driven to supply hydraulic pressure to the first hydraulic circuit that supplies hydraulic pressure to the first cylinder for cabot and a second cylinder that moves up and down the steps provided at the entrance / exit. The hydraulic pressure is commonly supplied from one hydraulic pump to the second hydraulic circuit. In the first hydraulic circuit, the first opening / closing solenoid valve opens and closes the hydraulic passage of the first cylinder, and the first switching solenoid valve switches the hydraulic pressure supply direction of the first cylinder, that is, the upper and lower sides of the cavit. On the other hand, in the second hydraulic circuit, the second opening / closing solenoid valve opens / closes the hydraulic passage of the second cylinder, and the second switching solenoid valve switches the hydraulic pressure supply direction of the second cylinder, that is, the up / down step.

The first opening / closing solenoid valve and the second opening / closing solenoid valve are
The hydraulic passage is blocked in the excited state (on state), and the hydraulic passage is made conductive in the non-excited state (off state). Also,
The first switching solenoid valve supplies oil pressure in the direction to tilt the cab in the excited state (on state), and the non-excited state (off state)
To supply the hydraulic pressure in the direction to return the cab, the second switching solenoid valve supplies the hydraulic pressure in the excited state (on state) to lower the step, and in the non-excited state (off state) to increase the step pressure. To supply.

The operation input to the control circuit is a manually operated tilt / step changeover switch, a manually operated tilt up / down instruction switch, a load switch operated by a load on the step, an upper limit switch of the step, and a step. From the lower limit switch. The control circuit controls the first opening / closing solenoid valve and the second opening / closing solenoid valve according to the setting position of the tilt / step switch, controls the first switching solenoid valve according to the setting position of the tilt up / down instruction switch, and sets the load switch. position,
The second switching solenoid valve is controlled according to the setting state of the upper limit switch and the setting state of the lower limit switch. This ensures that only the steps do not move before the person gets in.

Further, the control circuit supplies the exciting current supplied to the first opening / closing solenoid valve, the first switching solenoid valve, the second opening / closing solenoid valve, and the second switching solenoid valve when the key switch of the vehicle is in the off state. All prohibited. Therefore, the cab is not moved up and down and the steps are not moved up and down without the driver.

When a radio wave signal is generated from the portable key, the control circuit receives the radio wave signal and turns the second opening / closing solenoid valve into a hydraulic pressure cutoff state unless a specific signal arrives.

The operation input also includes the opening sensor output of the door for which the step is provided, and the control circuit detects that the opening sensor is open to the extent that a person can get on and off the door. Sometimes I activate the second hydraulic circuit,
Steps do not go up or down when no one is in and out.

In this way, by making the control circuit capable of executing all the control operations required for stepping on and off, the hydraulic circuit can be simplified and at the same time,
Since the reverse rotation operation of the electric motor for hydraulic pressure generation is unnecessary, the manufacturing cost can be reduced, and further, the control is controlled to the safe side when the power supply of the control circuit is stopped. When the driver wants to get on the vehicle, the step lowering operation can be performed remotely without touching the vehicle from outside the vehicle.

[0019]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a main part of a hydraulic system and a control system according to an embodiment of the present invention, FIG. 2 is a diagram showing respective operation inputs and control outputs of a control circuit according to the embodiment of the present invention, and FIG. FIG. 4 is a partial sectional front view showing the mounting state of the step, and FIG. 4 is a partial sectional side view showing the mounting state of the step in the embodiment of the present invention.

In the embodiment of the present invention, the first hydraulic circuit 10 for supplying the hydraulic pressure to the first cylinder 1 for the cavit and the second hydraulic circuit 10 for supplying the hydraulic pressure to the second cylinder 3 for moving up and down the step 2 provided at the entrance / exit. A hydraulic circuit 20, a hydraulic pump 4 that supplies hydraulic pressure to the first hydraulic circuit 10 and the second hydraulic circuit 20 in common, an electric motor 5 that drives the hydraulic pump 4, and an oil tank 8 are provided. In the hydraulic circuit 10,
A second hydraulic circuit 20 is provided with a first opening / closing solenoid valve 11 that opens and closes a hydraulic passage to and from the first cylinder 1, and a first switching solenoid valve 12 that switches the hydraulic pressure supply direction of the first cylinder 1.
And a second switching solenoid valve 22 for switching the hydraulic pressure supply direction of the second cylinder, and a second switching solenoid valve 22 for switching the hydraulic pressure supply direction of the second cylinder. A single control circuit 6 for controlling the opening / closing solenoid valve 11, the first switching solenoid valve 12, the second opening / closing solenoid valve 21, and the second switching solenoid valve 22 is provided. A check valve 13 for pressure backflow prevention is arranged in each of the pipelines that connect the hydraulic pump 4, the first hydraulic circuit 10, the second hydraulic circuit 20, and the oil tank 8.

Each of the first opening / closing solenoid valve 11 and the second opening / closing solenoid valve 21 shuts off the hydraulic passage in the excited state (on state) and connects the hydraulic passage in the non-excited state (off state).
The first switching solenoid valve 12 supplies the hydraulic pressure in the excited state (on state) to tilt the cab, and supplies the hydraulic pressure in the non-excited state (off state) to return the cab. The second switching solenoid valve 22 supplies the hydraulic pressure in the excited state (on state) in the direction to lower the step, and supplies the hydraulic pressure in the non-excited state (off state) to increase the step.

As shown in FIG. 2, the operation inputs are a tilt / step changeover switch 31 that is manually operated, a tilt up / down instruction switch 32 that is manually operated, and a load switch 33 that operates with the load on step 2. , Step 2 upper limit switch 34 and lower limit
The control circuit 6 includes a switch 35 and means for controlling the first opening / closing solenoid valve 11 and the second opening / closing solenoid valve 21 according to the setting position of the tilt / step changeover switch 31;
A means for controlling the first switching solenoid valve 12 according to the set position of the tilt up / down instruction switch 32, and a load switch 33.
Means for controlling the second switching solenoid valve 22 in accordance with the set position of the above and the setting states of the upper limit switch 34 and the lower limit switch 35, and when the key switch 36 of the vehicle is in the OFF state, the above four solenoid valves are supplied. Means for prohibiting all exciting currents.

Furthermore, a key 7 that is portable and generates a radio wave signal is provided, and the control circuit 6 has means for receiving this radio wave signal and a second opening / closing solenoid valve unless a specific signal arrives at this receiving means. 21 is a hydraulic pressure cutoff state, and the operation input includes an output of the opening / closing door 37 of the door for which the step 2 is provided. It includes means for activating the second hydraulic circuit 20 only when it is open enough for a person to get on and off.

In addition to the above-mentioned operation input, the control circuit 6 has the cab at the lower end and the cab lock switch 41 which is turned on when mechanically locked, and when the cab is at the upper end. The cab stopper switch 42 that is turned on, the door switches 43 _L and 43 _R that are turned on when the left and right doors are opened, and the neutral switch that is turned on when the transmission is in the neutral position 44, a parking switch 45 that is turned on during parking, and a door lock switch 46 that is turned on when the door is locked. The detection output from the vehicle speed sensor 9 is input and is connected to an antenna 47 that receives a radio signal from the key 7.

Also, a tilt buzzer 51 that makes a sound during the tilting operation of the cab, a tilt display lamp 52 that is placed outdoors and lights up when the tilt and up / down instruction switch 32 is operated, and when the step 2 is moving up and down. Outputs to the step operation alarm buzzer 53 that sounds and the door lock actuators 54 _R and 54 _L that locks and unlocks the door.

The key 7 includes a door lock button 7a and an unlock button 7b for inputting an instruction for locking and unlocking the door by the door lock actuators 54 _R and 54 _L , and ascending and descending in step 2. Step up instruction button 7c for inputting operation instructions
And a step-down instruction button 7d.

Next, various operations in the embodiment of the present invention thus constructed will be described. First, the step lowering operation will be described. FIG. 5 is a diagram for explaining the step lowering operation in the embodiment of the present invention, and FIG. 6 is a flow chart showing the flow of the step lowering operation by the control circuit in the embodiment of the present invention.

The control circuit 6 controls the output of the vehicle speed sensor 9 to "0", the parking switch 45 to "on", and the neutral switch when the vehicle is stopped and the tilt / step switch 31 is switched to the step operation side. Enter "ON" at 44 and "OFF" at the key switch 36 to check whether the door switch 43 _R or 43 _L is in the ON state. Door switch 43 _R or 43
If any of _L is in the ON state, it is confirmed whether the opening sensor 37 provided on the door is in the ON state. If it is in the ON state, it is confirmed whether or not there is a step-down instruction button 7d of the key 7 for the step-down instruction.

If there is a descending instruction in step 2, the timer is operated and it is confirmed again whether or not the step descending signal has been input. If there is a descending instruction, the timer is stopped after 2 seconds, and within 2 seconds. Check if the step down signal is input twice. This operation is performed for the purpose of confirming for safety whether or not the step down signal is surely input.

Here, when a person rides on the step 2, the load sensor 33 is turned on, and when the control circuit 6 receives this output, the first opening / closing solenoid valve 11 is turned on and the hydraulic pump 4 operates. The pipeline for raising the first cylinder 1 for the cavit is shut off, the first switching solenoid valve 12 is turned off, and the hydraulic pressure from the hydraulic pump 4 is switched to be supplied to the side for lowering the first cylinder 1. Therefore, even if an abnormality occurs in the first opening / closing solenoid valve 11 and it becomes conductive, the hydraulic pressure is supplied to the side for lowering the cab, so that safety is ensured.

Then, the second switching solenoid valve 22 is turned off so that the hydraulic pressure from the hydraulic pump 4 is supplied to the side for lowering the second cylinder 3 for stepping up and down. Is turned off to bring the conduit to the second cylinder 3 into conduction. Here, power is supplied to the electric motor 5 to drive the hydraulic pump 4. The hydraulic pressure from the hydraulic pump 4 is supplied to the side for lowering the second cylinder 3 via the second switching solenoid valve 22 and the second opening / closing solenoid valve 21 as shown by the arrow in FIG. At the same time, the step operation alarm buzzer 53 is sounded to notify that step 2 is descending and the timer is operated.

When step 2 reaches the lower end and comes into contact with the lower limit switch 35 to be turned on,
The power supply to the electric motor 5 is cut off to stop the driving of the hydraulic pump 4. When the lower limit switch 35 is not turned on due to a failure or the like and the timer has passed the predetermined time t ₀ seconds, the power supply to the electric motor 5 is similarly cut off and the driving of the hydraulic pump 4 is stopped. As a result, step 2 goes down.

In this way, when the door is locked after descending step 2 and getting off, the door is locked according to the flow of the door locking operation shown in FIG. Even if the key switch is off, the control circuit 7 is always supplied with the voltage from the backup power source. Therefore, when the door lock button 7a of the key 7 is pressed from outside the vehicle, the control circuit 6 sends the signal to the antenna 47. To confirm whether or not it is a door lock instruction.

If it is a door lock instruction, the code of the transmitted signal is compared with the code recorded in advance to confirm whether or not they match. If they match, the door lock actuators 54 _L and 54 _R are driven to lock the door.

Next, the operation of unlocking the door from outside the vehicle will be described. FIG. 8 shows a door according to the embodiment of the present invention.
It is a flowchart which shows the flow of an unlocking operation.

When the lock release button 7b of the key 7 is pressed from the outside of the vehicle, the control circuit 6 receives the signal via the antenna 47 and confirms whether or not the door unlock instruction is given. If it is an instruction to unlock the door, the code of the transmitted signal is compared with the code recorded in advance to confirm whether or not they match. If they match, the door lock actuators 54 _R and 54 _L are driven to unlock the door.

Now, the ascending operation of step 2 in the case of getting on the vehicle after the door is unlocked will be described. FIG. 9 is a diagram for explaining the step raising operation in the embodiment of the present invention, and FIG. 10 is a flowchart showing the flow of the step raising operation by the control circuit in the embodiment of the present invention.

When the step-up instruction button 7c of the key 7 is pressed, the control circuit 6 receives the instruction signal via the antenna 47, and as described above, is the door unlocked by the key 7? Alternatively, check if it is unlocked manually. If the door is in the unlocked state, check whether the neutral switch 44, the parking switch 45, and the opening sensor 37 are in the on state and there is no output from the vehicle speed sensor 9 (vehicle speed is zero). To do. Next, it is confirmed whether or not the instruction from the key 7 is to raise step 2, and if it is the instruction for raising step 2, the timer is operated and it is again confirmed whether or not the step rise signal is input. If there is a rising instruction, the timer is stopped after 2 seconds, and it is confirmed whether or not the step rising signal is input twice within the 2 seconds. This operation is performed in order to safely confirm whether or not the step rising signal is surely input, as in the step descending operation.

Here, it is confirmed by turning on / off the load switch 33 whether or not a person is on the step 2.

If the load switch 33 is in the ON state, it means that a person is on the vehicle, and the first opening / closing solenoid valve 11 is in the ON state to disconnect the pipeline from the hydraulic pump 4 to the first cylinder 1 for the cabot. , Then the first switching solenoid valve 12
Is turned off to switch the hydraulic pressure from the hydraulic pump 4 so that the hydraulic pressure is supplied in a direction to lower the first cylinder 1. Further, the second switching solenoid valve 22 is switched to the ON state so that the hydraulic pressure from the hydraulic pump 4 is supplied to the side that raises the second cylinder 3 for step elevation.
1 is turned off so that the hydraulic pressure from the hydraulic pump 4 raises the second cylinder 3 so that the second cylinder 3 is electrically connected.

Here, power is supplied to the electric motor 5 to drive the hydraulic pump 4, and the second cylinder 3 is supplied to the second cylinder 3 via the second switching solenoid valve 22 and the second opening / closing solenoid valve 21 as shown by the arrow in FIG. Supply hydraulic pressure. The supply of this hydraulic pressure causes the second cylinder 3 to expand and raise the step 2. When the supply of hydraulic pressure is started, the step operation alarm buzzer 53 is sounded to notify that step 2 is rising, and the timer is operated.

The hydraulic pressure from the hydraulic pump 4 is also supplied to the first switching solenoid valve 12 side, but the first cylinder 1 is not supplied with hydraulic pressure because the first opening / closing solenoid valve 11 is closed.
When an abnormality occurs in the first opening / closing solenoid valve 11 and it becomes conductive, the hydraulic pressure is supplied to the first cylinder 1, but the cab rises because it is supplied to the side that lowers the first cylinder 1. Is prevented.

When step 2 reaches the rising end and comes into contact with the upper limit switch 34, it is turned on, and when the output is received, the power supply to the electric motor 5 is cut off and the drive of the hydraulic pump 4 is stopped. Further, when the predetermined time t ₁ elapses without the upper limit switch 34 being turned on due to a failure or the like, the timer stops the power supply to the electric motor 5 and the driving of the hydraulic pump 4 is stopped. As a result, step 2 goes up.

When the door lock button 7a of the key 7 is pushed in the case of raising the step 2 in this way to get on the vehicle and locking the door, the control circuit 6 receives the instruction signal as shown in FIG. Check if it is a door lock instruction and check the door lock actuators 54 _L and 54 _R.
To lock the door.

Also, as shown in FIG. 12, the key switch 3
When 6 is turned on and the door is locked by pushing down the door lock knob on the driver's side, the door lock switch 46 is turned on in synchronization with this, and the control circuit 6 receives the output and is set on the passenger side. Door lock actuator 54
_You can drive _R to lock the door. Further, as shown in FIG. 13, when the vehicle is started without the door being locked when the passenger gets in the vehicle, the control circuit 6 causes the vehicle to lock the door when the detection output from the vehicle speed sensor 9 exceeds a predetermined value. It is also possible to automatically lock the door by driving the actuators 54 _L and 54 _R. It should be noted that, in order to further enhance the safety of the step raising and lowering operations, the step raising button 7c and the step lowering instruction button 7d may be pushed several times within a certain time, for example, twice in two seconds.

Next, the cab raising operation in the embodiment of the present invention will be described. FIG. 14 is a diagram for explaining the cab raising operation in the embodiment of the present invention, and FIG. 15 is a flowchart showing the flow of the cab raising operation by the control circuit in the embodiment of the present invention.

The control circuit 6 includes a key switch 36, a parking switch 45, and a neutral switch 44.
Is turned on, and if it is turned on, it is checked whether the tilt / step switch 31 is operated to the tilt side. If it is operated to the tilt side, it is confirmed whether or not the tilt up / down instruction switch 32 is operated to the ascending side, and if it is operated to the ascending side, the tilt buzzer 51 is sounded to notify the execution of the ascending operation of the cab. To do.

First, the second opening / closing solenoid valve 21 is turned on to shut off the line to the second cylinder 3, and the second switching solenoid valve 22 is turned off to set the line on the supply side of the hydraulic pump 4 to the first line. The two cylinders 3 are switched so as to be connected to the lowering side. Next, the first switching solenoid valve 12 is turned on,
Further, the first opening / closing solenoid valve 11 is turned off to bring the conduit to the first cylinder 1 into conduction.

Here, it is confirmed whether or not the lock release lever is manually pulled and the cab lock switch 41 is turned on to release the cab lock. If the cab lock is released, the electric power is supplied to the electric motor 5. The hydraulic pump 4 is supplied to drive the hydraulic pump 4. At this time, the tilt display lamp 52 is turned on to notify that the cab is being raised.

By driving the hydraulic pump 4, hydraulic pressure is supplied from the first switching solenoid valve 12 through the first opening / closing solenoid valve 11 to the rising side of the first cylinder 1 to raise the rod 1a and tilt the cab. From the hydraulic pump 4, the second switching solenoid valve 22
Although the hydraulic pressure is also supplied to the side where the step 2 of the second cylinder 3 is lowered after passing through, the second opening / closing solenoid valve 21 is in the shut-off state, so the pressure oil is not supplied to the second cylinder 3 The raising / lowering operation of 2 is not performed.

When the tilt up / down instruction stitch 32 is switched to the neutral position in the middle of the ascending operation, the ascending operation is stopped at that position, and when it is switched to the descending position, the descending operation is started. When the ascending operation is continued and the cab comes into contact with the cab stopper switch 42, the cab is turned on to notify that the ascending end has been reached. As a result, the control circuit 6 shuts off the power supply to the electric motor 5 and stops the supply of hydraulic pressure from the hydraulic pump 4 to the first cylinder 1. At the same time, the sounding of the tilt buzzer 51 is stopped, and it is confirmed whether or not the tilt up / down instruction switch 32 has been operated to the off state (neutral position). If the tilt up / down instruction switch 32 has been operated to the off state, the tilt display lamp 52 is turned off.

Since the check valve 13 is arranged in the pipeline connecting the hydraulic pump 4, the first cylinder 1, the second cylinder 3, and the oil tank 8, the backflow of the hydraulic pressure in each pipeline is performed. Is prevented.

Next, the cab lowering operation will be described.
16 is a diagram for explaining the cab lowering operation in the embodiment of the present invention, and FIG. 17 is a flow chart showing the flow of the cab lowering operation by the control circuit in the embodiment of the present invention.

The control circuit 6 includes the key switch 36, the parking switch 45, and the neutral switch 4.
4 is in the on state, and if it is in the on state, it is confirmed whether the tilt / step switch 31 is operated to the tilt side. If it is operated to the tilt side, it is confirmed whether or not the tilt up / down instruction switch 32 is operated to the descending side, and if it is operated to the descending side, the tilt buzzer 51 is sounded to perform the descending operation of the cab. Notice.

First, the second opening / closing solenoid valve 21 is turned on to shut off the line to the second cylinder 3, and the second switching solenoid valve 22 is turned off to set the line on the supply side of the hydraulic pump 4 to the first line. The two cylinders 3 are switched so as to be connected to the lowering side. Next, the first switching solenoid valve 12 is turned off,
Further, the first opening / closing solenoid valve 11 is turned off to bring the conduit to the first cylinder 1 into conduction.

Here, the ON state of the cab stopper switch 42 indicating that the cab is at the rising end is confirmed, and if it is in the ON state, it is confirmed whether or not the tilt up / down instruction switch 32 is switched to the descending side. . If it is switched to the descending side, power is supplied to the electric motor 5 to drive the hydraulic pump 4. At this time, the tilt display lamp 52 is turned on to notify that the cab is descending.

By driving the hydraulic pump 4, hydraulic pressure is supplied from the first switching solenoid valve 12 through the first opening / closing solenoid valve to the descending side of the first cylinder 1 to lower the rod 1a to return the cab from the tilted state. Hydraulic pressure is also supplied from the hydraulic pump 4 to the side for lowering step 2 of the second cylinder 3 via the second switching solenoid valve 22 as in the raising operation, but the second opening / closing solenoid valve 21 is in the shut-off state. Therefore, the hydraulic pressure is not supplied to the second cylinder 3, and the lifting / lowering operation of step 2 is not performed.

When the cab finishes descending, the lock release lever is returned to indicate that the cab is locked.
The OFF state of the switch 41 is confirmed. If the switch 41 is in the OFF state, the power supply to the electric motor 5 is cut off and the hydraulic pressure supply from the hydraulic pump 4 to the first cylinder 1 is stopped. At the same time, the sounding of the tilt buzzer 51 is stopped, and it is confirmed whether or not the tilt up / down instruction switch 32 has been operated to the off state (neutral position). If the tilt up / down instruction switch 32 has been operated to the off state, the tilt display lamp 52 is turned off.

[0059]

As described above, according to the present invention, the hydraulic circuit can be simplified and the rotation direction of the electric motor for generating hydraulic pressure can be limited to one direction, so that the manufacturing cost can be reduced. In addition, when the power of the control circuit is stopped, it can be controlled to the safe side, and when the driver wants to get on the vehicle, the step lowering operation can be performed from outside the vehicle. effective.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of essential parts of a hydraulic system and a control system according to an embodiment of the present invention.

FIG. 2 is a diagram showing each operation input and control output of the control circuit in the embodiment of the present invention.

FIG. 3 is a partial cross-sectional front view showing a mounting state of steps in the embodiment of the present invention.

FIG. 4 is a partial cross-sectional side view showing a mounting state of steps in the embodiment of the present invention.

FIG. 5 is a diagram illustrating a step lowering operation in the embodiment of the present invention.

FIG. 6 is a flowchart showing the flow of a step lowering operation by the control circuit in the embodiment of the present invention.

FIG. 7 is a flowchart showing a flow of a door lock operation in the embodiment of the present invention.

FIG. 8 is a flowchart showing a flow of a door unlocking operation in the embodiment of the present invention.

FIG. 9 is a diagram illustrating a step raising operation in the embodiment of the present invention.

FIG. 10 is a flowchart showing the flow of a step raising operation by the control circuit in the embodiment of the present invention.

FIG. 11 is a flowchart showing an example of a door lock operation in the embodiment of the present invention.

FIG. 12 is a flowchart showing another example of the door lock operation in the embodiment of the present invention.

FIG. 13 is a flowchart showing still another example of the door lock operation in the embodiment of the present invention.

FIG. 14 is a diagram illustrating a cab raising operation according to the embodiment of the present invention.

FIG. 15 is a flowchart illustrating a cab raising operation by the control circuit according to the embodiment of the present invention.

FIG. 16 is a diagram illustrating a cab lowering operation according to the embodiment of the present invention.

FIG. 17 is a flowchart illustrating a cab raising operation by the control circuit according to the embodiment of the present invention.

[Explanation of symbols]

1 first cylinder 1a rod 2 step 2a arm 3 second cylinder 4 hydraulic pump 5 electric motor 6 control circuit 7 key 7a door lock button 7b lock release button 7c step up instruction button 7d step descent instruction button 8 oil tank 9 vehicle speed sensor 10 First hydraulic circuit 11 First opening / closing solenoid valve 12 First switching solenoid valve 13 Check valve 20 Second hydraulic circuit 21 Second opening / closing solenoid valve 22 Second switching solenoid valve 31 Tilt / step changeover switch 32 Tilt up / down instruction switch 33 Load switch 34 upper limit switch 35 Rowa limit switch 36 key switch 37 opening sensor 41 cab switch 42 cab stopper switch 43 _L, 43 _R door switch 44 neutral switch 45 parking Su Pitch 46 door lock switch 47 antenna 51 tilt buzzer 52 tilt display lamp 53 step operation warning buzzer 54 _L, 54 _R door lock actuator

Claims (6)

[Claims] 1. A first hydraulic circuit for supplying hydraulic pressure to a first cylinder for a cavitt, a second hydraulic circuit for supplying hydraulic pressure to a second cylinder for moving up and down a step provided at an entrance / exit, and the first hydraulic circuit. Circuit and a hydraulic pump that supplies a hydraulic pressure to the second hydraulic circuit in common, the first hydraulic circuit includes a first opening / closing solenoid valve for opening and closing a hydraulic passage between the first cylinder and the first hydraulic circuit, and A second switching solenoid valve that opens and closes a hydraulic passage between the second hydraulic circuit and the second cylinder, and a hydraulic supply of the second cylinder. A step-up / lower device for a cab-over vehicle, comprising a second switching solenoid valve for switching directions, and one control circuit for controlling the four solenoid valves according to an operation input. 2. The first opening / closing solenoid valve and the second opening / closing solenoid valve cut off a hydraulic passage in an excited state and connect a hydraulic passage in a non-excited state, respectively, and the first switching solenoid valve in a excited state is a cab. The hydraulic pressure is supplied in the direction of tilting and the hydraulic pressure is supplied in the direction of returning the cab in the non-excited state, and the second switching solenoid valve supplies the hydraulic pressure in the direction of lowering the step in the excited state and raises the step in the non-excited state. The step lift device for a cab-over vehicle according to claim 1, wherein the hydraulic pressure is supplied in the direction in which the hydraulic pressure is applied. 3. The operation input includes a manually operated tilt / step changeover switch, a manually operated tilt up / down instruction switch, a load switch operated by a load on a step, an upper limit switch of the step, and A lower limit switch, wherein the control circuit controls the first opening / closing solenoid valve and the second opening / closing solenoid valve according to a setting position of the tilt / step changeover switch, and sets the tilt up / down instruction switch. 3. A means for controlling the first switching solenoid valve according to a position, and a means for controlling the second switching solenoid valve according to a set position of the load switch and a set state of two limit switches. Step lift device for the cab-over vehicle described. 4. The step lift device for a cabover vehicle according to claim 2, wherein the control circuit includes means for prohibiting all of the exciting currents supplied to the four solenoid valves when the key switch of the vehicle is in an off state. 5. A portable key is provided which generates a radio wave signal, said control circuit receiving means for receiving this radio wave signal, and said second opening / closing solenoid valve unless a specific signal arrives at this receiving means. 5. The step-lifting device for a cab-over vehicle according to claim 1, further comprising: means for turning off the hydraulic pressure. 6. The operation input includes an opening sensor output of an entrance / exit door provided with the step, and the control circuit uses the opening sensor to open the door so that a person can get on / off the door. 4. The step-up / lower device for a cab-over vehicle according to claim 1, further comprising means for enabling the second hydraulic circuit only.