JP7577019B2 - Seat opening/closing drive device for vehicle cargo box - Google Patents

Description

The present invention relates to a seat opening/closing drive device for a cargo box for a vehicle, and in particular to a seat opening/closing drive device for a cargo box for a vehicle, which comprises at least a cargo box having an opening and mounted on a vehicle body frame, a seat journaled on the cargo box and capable of swinging open/close between a predetermined open position and a closed position relative to the opening, an electric motor for driving the seat to open/close, a battery connected to the motor so that it can be energized, a current mode switching means provided in the current circuit between the motor and the battery and capable of switching the current mode from the battery to the motor so that the motor can rotate in either the forward or reverse direction, and a stop switch capable of stopping the current from the battery to the motor.

The above-mentioned seat opening and closing drive device is well known in the art, for example as shown in Patent Document 1.

JP 2019-127205 A

The seat opening/closing drive device in Patent Document 1 creates a short circuit in the motor to prevent the seat from continuing to move due to inertia or its own weight after the power supply to the motor is stopped, and this short circuit exerts a braking effect. However, in order to create this short circuit, it is necessary to keep current flowing from the battery to relay 242 via microcomputer 23 even after the power supply to the motor is stopped. This causes a problem in that current continues to flow through relay 242 even after the power supply to the motor is stopped, resulting in unnecessary power consumption.

The present invention was made in consideration of the above circumstances, and aims to provide a seat opening and closing drive device for a vehicle cargo box that can solve the above problems with a simple structure.

In order to achieve the above object, the present invention provides a seat opening/closing drive device for a vehicle cargo box, which includes at least a cargo box having an opening and mounted on a vehicle body frame, a seat pivotally supported by the cargo box and capable of swinging between a predetermined open position and a closed position relative to the opening, an electric motor for driving the seat to open and close, a battery connected to the motor so that it can be energized, a current mode switching means provided in a current circuit between the motor and the battery and capable of switching the current mode from the battery to the motor so that the motor can rotate in either the forward or reverse direction, and a stop switch capable of stopping the current from the battery to the motor. The first feature of the device is that the device includes a seat stop detection means capable of detecting that the seat has stopped in relation to the stop of the current by the stop switch, and a self-holding means for holding the current mode switching means in a specific switching state so that a short circuit of the motor is formed only after the current to the motor is stopped and until the seat stop detection means detects the stop of the seat.

In addition to the first feature, the present invention has a second feature in that the self-holding means includes a normally open self-holding opening/closing means capable of opening and closing a connection path that connects the battery and the motor in series in the current-carrying circuit, and the self-holding opening/closing means is closed after the current is stopped until the sheet stop detection means detects the stop of the sheet, and is opened after the stop is detected.

In addition to the first or second feature, the present invention has a third feature in that the sheet stop detection means detects the stop of the sheet based on the passage of a predetermined time from the stop of the current by the stop switch.

According to a first feature of the present invention, a seat opening/closing drive device includes a motor for opening and closing a seat, a battery connected to the motor so that it can be energized, a current mode switching means provided in a current circuit between the motor and the battery and capable of switching the current mode from the battery to the motor so that the motor can rotate in either the forward or reverse direction, and a stop switch capable of stopping the current from the battery to the motor, and includes a sheet stop detection means capable of detecting that the seat has stopped in relation to the stop of current by the stop switch, and a self-holding means for holding the current mode switching means in a specific switching state so that a short circuit of the motor is formed only after current to the motor is stopped and until the sheet stop detection means detects the stop of the sheet. As a result, after current to the motor is stopped, the current mode switching means is held in the specific switching state that forms a short circuit only for a short period of time until the sheet stop detection means detects the stop of the sheet, and a braking effect is exerted, so that power consumption for forming a short circuit after current to the motor is stopped can be suppressed and power saving effects can be enhanced.

According to the second feature, the self-holding means includes a normally open self-holding opening/closing means capable of opening and closing the connection path that connects the battery and the motor in series in the current-carrying circuit, and this self-holding opening/closing means is closed after the current is stopped until the sheet stop detection means detects the stop of the sheet, and opens after the stop is detected. As a result, after the stop of the sheet is detected, the current to the motor is reliably cut off by the self-holding opening/closing means, thereby enhancing the protection effect of the motor. Moreover, the self-holding opening/closing means for terminating the formation of a short circuit also serves as a motor protection means, which contributes to simplifying the circuit configuration.

According to the third feature, the sheet stop detection means detects the stop of the sheet based on the passage of a predetermined time from the stop of the current supply by the stop switch, so the detection configuration is much simpler than when the stop of the sheet is detected by a sensor, which can contribute greatly to cost reduction.

FIG. 1 is a side view showing an embodiment of a dump truck to which the present invention is applied. FIG. 2 is a rear view of the dump truck (as viewed from the arrow 2 in FIG. 1 ). FIG. 1 is a front view showing an example of a controller for a seat opening/closing drive device; FIG. 4 shows a control circuit diagram of the seat opening/closing drive device and a time-series diagram of its operation, in which (A) shows the initial state, and (B) shows the state in which the forward/reverse switch is selected to the forward rotation position from the state shown in FIG. 4(A). The control circuit diagram and operation mode are shown in chronological order in relation to FIG. 4, where (C) shows the state in which the right operation switch is turned on from the state in FIG. 4(B), and (D) shows the state immediately after the forward/reverse switch is selected to the neutral (energization-stopped) position from the state in FIG. 5(C), i.e., before a predetermined time has elapsed (the seat is stopped). 1A is a simplified circuit diagram showing the switching mode of a switching means which is a main component of a motor driver as a current supply mode switching means, in which (a) shows the initial state, (b) shows the switching mode for rotating the motor forward, (c) shows the switching mode for rotating the motor reversely, and (d) shows the switching mode for forming a short circuit of the motor. FIG. 4 is a front view showing a modified example of the controller (corresponding to FIG. 3 );

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In Figures 1 and 2, a cargo box 2 with an opening O on its top surface is journaled on the vehicle frame 1 of a dump truck V as a vehicle so that it can tilt backward, and a well-known drive mechanism (not shown) that forcibly tilts the cargo box 2 backward is interposed between the cargo box 2 and the vehicle frame 1. In addition, a pair of left and right sheets S that can open and close at least a portion of the opening O of the cargo box 2 (both the left and right outer parts of the opening O in this embodiment) are attached to the upper edges of the left and right side panels 3, 3 of the cargo box 2.

The left and right seats S are composed of a sheet material 4 such as cloth, and a square-shaped seat frame 5 that holds the sheet material 4 in a specified rectangular shape. The base end shaft portion 5a of the seat frame 5, which extends in the front-to-rear direction, is rotatably supported by a number of bearing portions 6 provided at intervals on the upper edges of the left and right side panels 3, 3.

The output shafts of left and right electric motors ML, MR attached to the front end of the packing box 2 are linked to the left and right base end shaft parts 5a via reduction mechanisms 7. Therefore, when at least one of the left and right motors ML, MR is rotated in one direction, the sheet S on that side can be forcibly swung closed from the open position So where it hangs down from the bearing part 6 and extends along the outer surface of the side plate 3, through an intermediate horizontal position Sh where it extends horizontally outward from the bearing part 6, and an intermediate standing position Sv where it stands vertically from the bearing part 6, to a closed position Sc where it extends horizontally inward from the bearing part 6. When at least one of the left and right motors ML, MR is rotated in the other direction, the sheet S on that side can be forcibly swung open along the reverse path described above.

As is clear from FIG. 6, the left and right motors ML and MR are DC motors that can rotate forward and backward and have a first power receiving part Mo that serves as an input terminal during forward rotation (when the seat S is rotated open) and a second power receiving part Ms that serves as an input terminal during reverse rotation (when the seat S is rotated closed).

Figures 4 to 6 show an example of a seat opening/closing drive device that controls the drive of the left and right motors ML and MR independently to open and close the left and right seats S, the details of which will be described later.

In addition, a controller 8 is provided on the driver's seat of the dump truck V, for example on the instrument panel, to allow the operator to open and close the seat S at will (see FIG. 3). The operation section of this controller 8 is provided with operation knobs for a forward/reverse switch SWm that can select forward or reverse rotation of the left and right motors ML, MR and also serves as a power switch, as well as a left operation switch SWa and a right operation switch SWb for starting the rotational drive of the left and right motors ML, MR.

The forward/reverse switch SWm is composed of a toggle switch that can be switched and held in three positions. That is, the forward/reverse switch SWm is configured so that its operating knob can be selectively held in either the neutral position, a forward rotation selection position on one side of the neutral position, or a reverse rotation selection position on the other side. When it is in the neutral position, the system power supply 22 for the microcomputer 21 of the control device 20 (described later) is turned off, and when it is in the forward rotation selection position or the reverse rotation selection position, the system power supply 22 is turned on. The forward/reverse switch SWm also functions as a stop switch of the present invention that can stop the flow of electricity from the battery B to the motors ML and MR.

The left and right operating switches SWa, SWb are momentary switches that function as start buttons that individually start the rotational drive of the left and right motors ML, MR. When the system power supply 22 is on, pressing the operation knob once turns them on, and the on state continues even after the operation knob is released and returned to its original position. The on state of the operating switches SWa, SWb is then switched to the off state when the forward/reverse switch SWm is switched to the neutral position (see FIG. 6(D)).

Next, a specific example of a seat opening/closing drive device will be described. The seat opening/closing drive device includes the left and right motors ML, MR described above, a current supply circuit 10 that enables current to be supplied to each motor ML, MR and is provided between the battery B and each motor ML, MR, the group of switches described above (i.e., forward/reverse switch SWm and left/right operation switches SWa, SWb), and a control device 20 that controls the operation of the left and right motors ML, MR based on the operation input of the group of switches.

The electronic control system of the control device 20 mainly includes a microcomputer 21, a system power supply 22 (e.g., 5 V) that supplies the microcomputer 21, motor drivers DL, DR, and self-holding relays RyL, RyR, etc., which are controlled by the microcomputer 21, and is either built into the controller 8 or installed in its vicinity.

The system power supply 22 is connected in parallel to a first electric circuit 31 that runs from the battery B through the forward/reverse switch SWm to the system power supply 22, and a second electric circuit 32 that branches off from a connection path 10Rp (described later) of the current-carrying circuit 10 (particularly downstream of the self-holding relay RyR) and runs to the system power supply 22.

The switch group SWm, SWa, and SWb are connected to the input side of the microcomputer 21 so that they can input switch signals. In this case, the output signal from the forward/reverse switch SWm is connected to the input side of the microcomputer 21 via a forward/reverse selection signal line 33 that branches off from the first electric circuit 31 and has a resistor along the way.

Thus, the microcomputer 21 starts up when the system power supply 22 is turned on by energizing it, and shuts down when the power supply 22 is turned off.

The microcomputer 21 also has a timer function and functions as a sheet stop detection means capable of detecting that the sheet S has stopped in relation to the stop of the supply of electricity to the motors ML and MR by the forward/reverse switch Swm, which serves as a stop switch. That is, the microcomputer 21 measures the elapsed time from the stop of the supply of electricity to the motors ML and MR, and when the elapsed time reaches a predetermined time, it determines that the sheet S has stopped.

In this case, the above-mentioned predetermined time is preset as the minimum time required for the rotation of the seat S to be reliably stopped by the braking effect caused by the formation of a short circuit in the motors ML and MR after the power supply to the motors ML and MR is stopped.

The left and right motor drivers DL, DR are connected to the left and right motor connection paths 10Lp, 10Rp, respectively, which function as power lines connecting the battery B and the left and right motors ML, MR in series in the current supply circuit 10, and function independently of each other. Since the circuit configurations of the left and right motor drivers DL, DR are exactly the same, only the motor driver DL for the left motor ML is explained and illustrated in Figure 6, and the explanation and illustration of the motor driver DR for the right motor MR is omitted.

As is clear from FIG. 6, the connection path 10Lp for the left motor ML is connected to earth via first and second branch paths 11, 12 that are connected in parallel to the connection path 10Lp for the left motor ML. A normally open first forward rotation opening/closing means 13 and a normally open first reverse rotation opening/closing means 15 that open and close the first branch path 11 individually are provided in series, and a normally open second forward rotation opening/closing means 14 and a normally open second reverse rotation opening/closing means 16 that open and close the second branch path 12 individually are provided in series.

A reverse current path 17 branches off from the first forward rotation opening/closing means 13 and the first reverse rotation opening/closing means 15 of the first branch path 11, and a forward current path 18 branches off from the second forward rotation opening/closing means 14 and the second reverse rotation opening/closing means 16 of the second branch path 12. The reverse current path 17 is connected to the second power receiving part Ms of the left motor ML (i.e., the terminal that serves as the input side when the motor rotates in the reverse direction), and the forward current path 18 is connected to the first power receiving part Mo of the corresponding motors ML and MR (i.e., the terminal that serves as the input side when the motor rotates in the forward direction).

Each of the above-mentioned opening and closing means 13 to 16 is composed of, for example, a FET (field effect transistor) that responds to a control signal from the microcomputer 21.

As described below, each of the opening/closing means 13-16 is normally held in an open state, blocking the corresponding first and second branch paths 11, 12. When a motor operation signal is output from the microcomputer 21 to each of the opening/closing means 13-16, the opening/closing means switches to a closed state, opening the corresponding branch paths 11, 12, and allowing current to flow in the forward and reverse directions to the motor ML (MR).

For example, FIG. 6(a) shows the initial state in which all opening/closing means 13-16 are open (i.e., the standby state in which the seat S is stopped), FIG. 6(b) shows the forward rotation drive state of the motor ML (MR) in which only the first and second forward rotation opening/closing means 13, 14 are closed (i.e., the seat S is rotated open), and FIG. 6(c) shows the reverse rotation drive state of the motor ML (MR) in which only the first and second reverse rotation opening/closing means 15, 16 are closed (i.e., the seat S is rotated closed).

Furthermore, Fig. 6(d) shows a brake operating state in which only the first forward rotation opening/closing means 13 and the second reverse rotation opening/closing means 16 are closed to form a short circuit of the motor ML (MR). Note that when a short circuit is formed in the motor ML (MR) in a non-energized state, an electromotive force is generated when the motor ML (MR) rotates due to the inertia of the sheet S, etc., and this becomes a rotational load that brakes the sheet S. This is well known, as is clear from the description in Patent Document 1.

The left and right motor drivers DL, DR constitute a current mode switching means capable of switching the current mode from the battery B to each of the motors ML, MR so that the left and right motors ML, MR can rotate in either the forward or reverse direction.

The seat opening/closing drive device also includes a self-holding means H that holds the motor drivers DL, DR (energization mode switching means) in a specific switching state so that a short circuit of the motors ML, MR is formed in the energization circuit 10 (more specifically, the motor drivers DL, DR) only after the power supply to the motors ML, MR is stopped until the microcomputer 21, which serves as the seat stop detection means, detects that the seat S has stopped.

In this embodiment, the self-holding means H includes normally open self-holding relays RyL, RyR that can open and close the power line portion (i.e., the first and second connection paths 10Lp, 10Rp) of the current-carrying circuit 10 that connects the battery B and the motors ML, MR in series, and the microcomputer 21 that can control the operation of the relays RyL, RyR. The self-holding relays RyL, RyR are an example of the self-holding opening and closing means of the present invention.

The self-holding relays RyL, RyR have normally open relay contacts that open and close the first and second connection paths 10Lp, 10Rp, and a relay coil Rc that is linked to this relay contact is connected to the signal output side of the microcomputer 21. Thus, when the relay coil Rc receives a motor operation command signal from the microcomputer 21 (and thus current is started to flow to the motors ML, MR), it becomes excited and closes the self-holding relays RyL, RyR.

When the motors ML, MR are energized, and even after de-energization, the relay coil Rc continues to be energized by the brake command signal from the microcomputer 21, keeping the self-holding relays RyL, RyR closed until the microcomputer 21 (sheet stop detection means) detects that the sheet S has stopped, thereby maintaining the conductive state of the first and second connection paths 10Lp, 10Rp. Next, when the microcomputer 21 detects that the sheet S has stopped, the relay coil Rc becomes de-energized, opening the self-holding relays RyL, RyR, thereby cutting off the first and second connection paths 10Lp, 10Rp.

In the embodiment, the microcomputer 21 executes a control mode in which the relay coil Rc is continuously turned on (excited) to maintain the self-holding relays RyL, RyR in a closed state for a predetermined period after the power supply to the motors ML, MR is stopped until the microcomputer 21 (sheet stop detection means) detects the stop of the sheet S. However, instead of this control mode, a control mode may be adopted in which the relay coil Rc is intermittently and alternately turned on and off during the above-mentioned predetermined period, and the self-holding relays RyL, RyR are repeatedly opened and closed in short intervals. In the latter control mode, the braking effect caused by the formation of a short circuit in the motors ML, MR is reduced, but the circuit load can be reduced.

Next, the operation of this embodiment will be explained mainly with reference to Figures 4 to 6.

Figure 4 (A) shows the initial state (i.e., standby state), in which the forward/reverse switch SWm is in the neutral position and power supply from battery B to the system power supply 22 (and therefore the microcomputer 21) and motors ML and MR is stopped.

When the forward/reverse switch SWm is switched from the initial state to the forward selection position or reverse selection position, as shown in FIG. 4(B), power is supplied to the system power supply 22 via the first electric circuit 31, and the microcomputer 21 enters an activated state. If the left and right operation switches SWa and SWb are not pressed in this state, power has not yet started being supplied to the motors ML and MR. Note that FIG. 4(B) shows an example in which the forward/reverse switch SWm is in the forward selection position.

When at least one of the left and right operation switches SWa and SWb is pressed while the microcomputer 21 is in the activated state shown in FIG. 4B, the circuit state is switched to that shown in FIG. 5C. That is, based on the pressing input, the activated microcomputer 21 outputs a motor operation (forward rotation) command signal to the corresponding motor driver DL and DR, and the relay coil Rc is excited to close the self-holding relays RyL and RyR. This drives the motors ML and MR on the same side in the forward direction (see FIG. 6B), and the seat S on the same side rotates to open. At this time, power is also supplied from the second electric circuit 32 to the system power supply 22. Note that FIG. 5C shows an example in which the right operation switch SWb is pressed.

In contrast, even if the forward/reverse switch SWm is held in the reverse selection position from the initial state shown in FIG. 4A, power is supplied to the system power supply 22 via the first electric circuit 31, and the microcomputer 21 is in an activated state. In this state, when at least one of the left and right operation switches SWa, SWb is pressed, the activated microcomputer 21 outputs a motor operation (reverse) command signal to the corresponding motor driver DL, DR based on the pressing operation input, and the relay coil Rc is excited to close the self-holding relays RyL, RyR. This causes the motors ML, MR on the same side to rotate in the reverse direction (see FIG. 6C) and close the seat S on the same side. At this time, power is also supplied to the system power supply 22 from the second electric circuit 32.

In addition, in the state of FIG. 5(C), for example, when the forward/reverse switch SWm is operated to return to the neutral position, the microcomputer 21 outputs a brake command signal to the motor drivers DL, DR based on the operation input, instead of the motor operation command signal (see FIG. 5(D)). As a result, in the motor drivers DL, DR, as is clear from FIG. 6(d), the power supply from the battery B to the motors ML, MR is stopped and a short circuit is formed in the motors ML, MR, so that the motors ML, MR can be effectively braked and the rotation of the seat S is quickly stopped. In this case, at the same time that the forward/reverse switch SWm is operated to return to the neutral position, the power supply from the first electric circuit 31 to the system power supply 22 is cut off, but the self-holding relays RyL, RyR are held in a closed operating state and power is supplied to the system power supply 22 from the second electric circuit 32, so the microcomputer 21 continues to be activated.

At this time, the microcomputer 21 measures the elapsed time from the return operation of the forward/reverse switch SWm to the neutral position (i.e., from the de-energization of the motors ML and MR), and when it reaches a preset time, it determines that the rotation of the seat S has stopped and opens the self-holding relays RyL and RyR. This cuts off the power supply from the second electric circuit 32 to the system power supply 22, and the microcomputer 21 is shut down, so that the control device 20 for the seat opening/closing drive device stops completely, and the control device 20 returns to the initial state of FIG. 4(A).

In this way, while the seat S is rotating, the power supply to the motors ML and MR is stopped in response to the operation of returning the forward/reverse switch SWm (stop switch) to the neutral position (stop operation), but until the microcomputer 21 (seat stop detection means) detects the stop of the seat S, the microcomputer 21 (self-holding means H), which is maintained in an activated state by the power supply from the second electric circuit 32 instead of the first electric circuit 31, forms the short circuit with the motor drivers DL and DR. In other words, when the first electric circuit 31 is interrupted by the stop operation of the forward/reverse switch SWm (stop switch), the second electric circuit 32 functions as a specific electric circuit for operating the self-holding means H to set the motor drivers DL and DR to a specific switching state.

When the microcomputer 21 (sheet stop detection means) detects that the sheet S has stopped, it opens the self-holding relay RyR to cut off the second electric circuit 32 (i.e., the specific electric circuit that operates the self-holding means H to put the motor drivers DL, DR into a specific switching state when the first electric circuit 31 is cut off to stop the current flow to the motors ML, MR).

As described above, the seat opening/closing drive device of the embodiment is equipped with a microcomputer 21 (i.e., seat stop detection means) that can detect that the seat S has stopped operating due to the stopping of the supply of electricity to the motors ML and MR based on the return operation of the forward/reverse switch SWm (i.e., the stop switch) to the neutral position, and a self-holding means H (more specifically, self-holding relays RyL, RyR and the microcomputer 21) that holds the motor drivers DL and DR (i.e., the current supply mode switching means) in a specific switching state so that a short circuit of the motors ML and MR is formed in the current supply circuit 10 only after the supply of electricity to the motors ML and MR is stopped and only until the microcomputer 21 detects that the seat S has stopped.

In other words, after the forward/reverse switch SWm is returned to the neutral position and power to the motors ML and MR is stopped, the microcomputer 21 maintains the motor drivers DL and DR (power supply mode switching means) in a specific switching state that forms the above-mentioned short circuit only for a short period of time until the microcomputer 21 (sheet stop detection means) detects that the sheet S has stopped, thereby achieving a braking effect. This keeps the power consumption required to form a short circuit after power to the motors ML and MR is stopped to a minimum, thereby enhancing the power saving effect.

The self-holding means H includes normally open self-holding relays RyL, RyR that can open and close the connection paths 10Lp, 10Rp that connect the battery B and the motors ML, MR in series in the current-carrying circuit 10. After the current to the motors ML, MR is stopped, these relays RyL, RyR keep the connection paths 10Lp, 10Rp conductive until the microcomputer 21 detects that the sheet S has stopped, and then cut them off. As a result, after the detection of the stop of the sheet S, the current to the motors ML, MR is reliably cut off by the self-holding relays RyL, RyR, thereby enhancing the protection effect of the motors ML, MR. Moreover, the self-holding relays RyL, RyR for terminating the formation of the short circuit also serve as the protection means for the motors ML, MR, which simplifies the circuit configuration accordingly.

Furthermore, the microcomputer 21 serving as the sheet stop detection means in this embodiment detects the stop of the sheet S based on the passage of a predetermined time from the stopping of the power supply to the motors ML and MR due to the operation input of the forward/reverse switch SWm (i.e., the stop switch). This makes it possible to greatly simplify the detection configuration and achieve cost savings compared to when the stop of the motors ML and MR or the sheet S is directly detected by a sensor.

The above describes an embodiment of the present invention, but various design changes can be made to the present invention without departing from the gist of the invention.

For example, in the above embodiment, a dump truck V is used as an example of a vehicle on which a cargo box 2 is mounted, but the present invention can also be implemented in various vehicles with cargo boxes other than dump trucks.

In the above embodiment, the seat S is pivotally supported on the left and right side panels 3 of the cargo box 2 so that it can swing open and close, but the present invention can also be implemented in a vehicle with a cargo box in which the seat is pivotally supported on the front panel (e.g., the front panel) or rear panel (e.g., the tailgate) of the cargo box 2 so that it can swing open and close.

In the above embodiment, the controller 8 for inputting the opening and closing of the seat S is disposed in the driver's seat of the vehicle, but the location of the controller is not limited to the embodiment, and the controller may be disposed in any suitable location that allows the worker to operate it at will, such as in an appropriate location on the vehicle frame 1 or the cargo box 3.

In the above embodiment, the electronic control system of the control device 20 (e.g., the microcomputer 21, the system power supply 22, the motor drivers DL, DR, etc.) is built into the controller 8 or installed in its vicinity, but the location where the electronic control system is installed is not limited to the embodiment, and it may be installed in a suitable location on the vehicle away from the controller 8 (e.g., the driver's seat, a cargo box, on the vehicle frame near the cargo box, etc.).

In the above embodiment, the forward/reverse switch SWm, which can select forward/reverse rotation of the motors ML and MR and also serves as a power switch, and the left and right operation switches SWa and SWb for starting the rotation of the left and right motors ML and MR are arranged side by side in the operation section of the controller 8. However, FIG. 7 shows a modified controller. That is, in this modified example, the power switch SWm', which is dedicated to turning the power on and off, the left and right forward start switches SWa' and SWbw' for starting the forward rotation of the left and right motors ML and MR, and the left and right reverse start switches SWa" and SWbw" for starting the reverse rotation of the left and right motors ML and MR are arranged side by side in the controller 8'. In this modified example, the power switch SWm' functions as a stop switch that can stop the supply of electricity to the motors ML and MR.

In the above embodiment and modified example, a forward/reverse switch SWm or a power switch SWm' is used as a stop switch capable of stopping the supply of electricity to the motors ML and MR, but the stop switch is not limited to the embodiment or modified example, and may be, for example, a relay that is cut off by a sensor or a timer. In that case, for example, a sensor is provided (or a timer is set) that can detect when the sheet S reaches the stop target position while opening or closing, and when the sheet S reaches the stop target position, the power supply to the motors ML and MR is cut off by the relay.

The target stopping position of the seat S may be the rotation end of the seat S (i.e., the position where the seat S abuts against the vehicle and cannot be rotated any further). In this case, the seat S cannot be rotated any further, so there is no problem with the seat S rotating due to inertia, etc. However, the formation of the short circuit described above can prevent the seat S from continuing to rotate forcibly and being pressed against the vehicle, resulting in damage.

In the above embodiment, FETs (field effect transistors) are used as the switching means 13-16 of the motor drivers DL, DR as the current flow mode switching means, but the switching means 13-16 are not limited to the embodiment, and other electronic components (e.g., relays) that perform the same circuit opening and closing function as FETs can also be used.

In the above embodiment, the self-holding relays RyL and RyR are used as the self-holding switching means for forming a short circuit of the motors ML and MR after the power supply to the motors ML and MR is stopped until the seat S stops. However, the self-holding switching means is not limited to the embodiment, and other electronic components (e.g., FETs) that perform the same circuit switching function as the relays RyL and RyR can also be used.

In addition, in this embodiment, a short circuit is formed in the motors ML and MR to obtain a braking effect even when the motors ML and MR are stopped either during forward or reverse rotation. However, the short circuit may be formed only during either forward or reverse rotation to obtain a braking effect.

In the above embodiment, the microcomputer 21 is used as a sheet stop detection means capable of detecting that the sheet S has stopped in relation to the stop of the power supply to the motors ML and MR by the forward/reverse switch Swm (stop switch). In other words, the microcomputer 21 indirectly detects the stop of the sheet from the elapsed time since the power supply to the motors ML and MR has stopped. However, the sheet stop detection means of the present invention is not limited to the embodiment, and the stop of the operation of the sheet S (or the motors ML and MR) can be detected by various methods. For example, the sheet can be determined to have stopped by detecting the stop of the rotation of the rotors of the motors ML and MR or the rotation of the gears of the reduction gears linked to the motors ML and MR. In this case, the sensors constitute the sheet stop detection means, and when they detect the stop of the rotation (and therefore the stop of the sheet S), the self-holding opening and closing means (relays RyL, RyR or FET) is cut off. It should be noted that the above sensors only need to be able to detect the rotation, and for example, a proximity sensor or an encoder may be used.

In the above embodiment, the self-holding opening/closing means (relays RyL, RyR or FET) opens and closes the connection paths 10Lp, 10Rp that connect the battery B and the motors ML, MR in series. However, the location of the self-holding opening/closing means is not limited to the embodiment. For example, a current path that is independent of the connection paths 10Lp, 10Rp and that only passes current from the battery B to the system power supply 22 may be provided, and the self-holding opening/closing means may be provided on that current path.

In the above embodiment, the microcomputer 21 also serves as the sheet stop detection means, cooperates with the self-holding opening/closing means (relays RyL, RyR or FET) to form the self-holding means H, and controls the operation of each opening/closing means 13-16 of the motor drivers DL, DR as the current supply mode switching means. However, the microcomputer 21 can be omitted as necessary. When the microcomputer 21 is omitted, the above-mentioned sensors functioning as the sheet stop detection means are used instead of the microcomputer 21, and the self-holding opening/closing means (relays RyL, RyR or FET) are operated in conjunction with these. In addition, with the omission of the microcomputer 21, the switch circuit can be reconfigured so that the opening/closing means 13-16 of the motor drivers DL, DR can select the switching mode shown in FIG. 6 based on, for example, the operation input to the forward/reverse switch SWm or the power switch SWm', or the operation input to the left/right operation switches SWa, SWb; SWa', SWb'; SWa" and SWb".

In the above embodiment, when the forward/reverse switch SWm (stop switch) is operated to stop the current to the motors ML and MR while the seat S is rotating, the self-holding means H is operated to switch the motor drivers DL and DR to a specific switching state by cutting off the first circuit 31. However, multiple specific circuits may be provided. In this case, when the microcomputer 21 (seat stop detection means) detects that the seat has stopped, all the specific circuits are cut off, thereby reducing the power consumption required to form a short circuit.

B: Battery DL, DR: Left and right motor drivers as current supply mode switching means H: Self-holding means ML, MR: Left and right motors RyL, RyR: Self-holding relay as self-holding opening/closing means S: Seat Sc: Closed position So: Open position SWm: Forward/reverse switch serving as a stop switch, also serving as a power switch SWm': Power switch dedicated to on/off switching as a stop switch V: Dump truck (vehicle)
1. Vehicle body frame 2. Cargo box 10. Current supply circuit 10Lp, 10Rp. Connection path 21. Microcomputer as seat stop detection means

Claims (3)

A seat opening/closing drive device for a vehicle cargo box comprising at least a cargo box (2) having an opening (O) and mounted on a vehicle body frame (1), a seat (S) pivotally supported on the cargo box (2) and capable of swinging open/close between a predetermined open position (So) and a closed position (Sc) relative to the opening (O), an electric motor (ML, MR) for driving the seat (S) to open/close, a battery (B) electrically connected to the motor (ML, MR), current supply mode switching means (DL, DR) provided in a current supply circuit (10) between the motor (ML, MR) and the battery (B) for switching a current supply mode from the battery (B) to the motor (ML, MR) so that the motor (ML, MR) can rotate in either a forward direction or a reverse direction, and a stop switch (SWm, SWm') for stopping current supply from the battery (B) to the motor (ML, MR),
a sheet stop detection means (21) capable of detecting that the sheet (S) has stopped in relation to the stop of the current supply by the stop switch (SWm, SWm');
and a self-holding means (H) for holding the current-flow mode switching means (DL, DR) in a specific switching state so that a short circuit of the motors (ML, MR) is formed only after the current to the motors (ML, MR) is stopped and only until the seat stop detection means (21) detects the stop of the seat (S). the self-holding means (H) includes normally-open self-holding opening/closing means (RyL, RyR) capable of opening and closing a connection path (10Lp, 10Rp) that connects in series between the battery (B) and the motor (ML, MR) of the current-carrying circuit (10);
2. The seat opening/closing drive device for a vehicle cargo box according to claim 1, wherein the self-retaining opening/closing means (RyL, RyR) is closed after the power supply is stopped until the seat stop detection means (21) detects the stop of the seat (S), and is opened after the stop detection. The seat opening/closing drive device for a vehicle cargo box according to claim 1 or 2, characterized in that the seat stop detection means (21) detects the stop of the seat (S) based on the lapse of a predetermined time from the stop of the current supply by the stop switch (Swm, SWm').

Images