JPS6234583B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a power source such as a storage battery, drive wheels and steering wheels provided on a vehicle body, a drive motor that drives the drive wheels by the power source, and a power source such as a storage battery. A speed control device that controls a drive motor, a servo motor that steers a steering wheel, a steering control device that controls the servo motor, and one operating lever that controls both the speed control device and the steering control device. This relates to an electric car equipped with

(b) Conventional technology Conventionally, steering control is performed based on the outputs of both a steering torque detection device that detects the steering torque when a steering device consisting of a steering wheel is steered, and a steering angle detection device that detects the steered steering angle. A device for controlling a motor for steering wheels is disclosed in Japanese Patent Application Laid-Open No. 48-50430.

Further, Japanese Utility Model Publication No. 50-24298 discloses a device that mechanically steers steering wheels and controls an engine that drives drive wheels by operating a single operating lever.

(c) Problems to be solved by the invention However, in the case of the invention disclosed in JP-A-48-50430, it is not possible to control the drive of the drive wheels by operating only the steering device. . Furthermore, in the case of the vehicle disclosed in Japanese Utility Model Publication No. 50-24298, the steering wheel is steered by mechanical connection of the operating lever, which requires force for steering and also has the disadvantage that the electric vehicle cannot run backwards. There is.

The present invention has been invented in view of the above points, and allows driving wheels and steering wheels to be controlled simultaneously by operating a single operating lever, as well as making it possible to move the vehicle backwards. - To provide an electric vehicle that has excellent directional control ability not only on uphill slopes but also on downhill slopes and can run safely.

(d) Means for Solving the Problems The present invention provides a power source, a drive wheel and a steering wheel provided on a vehicle body, a drive motor that drives the drive wheels in the forward and reverse directions using the power source, and a drive motor that drives the drive wheels in the forward and reverse directions and its rotation. a drive motor rotation control circuit that controls the number of rotations of the drive motor, a servo motor that steers the steering wheel, a steering control device that controls the forward and reverse rotation of the servo motor and its rotation angle, the rotation direction and rotation speed of the drive motor, and the servo motor. The drive motor rotation control circuit commands the direction of rotation and the rotation angle thereof, and controls both the drive motor rotation control circuit and the steering control device. The steering control device includes a group of switches that control the direction of rotation and the number of rotations depending on the direction of rotation, and the steering control device includes a control lever-linked variable resistor whose resistance value changes in conjunction with the movement of the control lever in the left and right directions; A changeover switch that detects high/low speed of the drive motor as the lever moves forward and backward, and a variable resistor for high speed and low speed that is switched by the changeover switch and whose resistance value changes in conjunction with the rotation of the servo motor. a position detection circuit having a variable resistor, and an output voltage from the position detection circuit due to a change in resistance value between the operating lever interlocking variable resistor and the low speed variable resistor or the operating lever interlocking variable resistor and the high speed variable resistor. A pulse generation circuit for forward rotation control that outputs a signal for forward rotation of the servo motor according to the magnitude of the output voltage from the position detection circuit, and a pulse generation circuit for reverse rotation control that outputs a signal for reverse rotation of the servo motor according to the magnitude of the output voltage from the position detection circuit. When the servo motor is rotated forward or reverse based on the signal from either the circuit, the pulse generation circuit for forward rotation control, or the pulse generation circuit for reverse rotation control, and no signal is input from either pulse generation circuit. Equipped with a servo motor rotation control circuit that performs forward/reverse rotation and stop of the servo motor by stopping the drive motor at high speed. This problem can also be solved by means of switching between the variable resistor for low-speed use and the variable resistor for low-speed use.

(E) Effect In such a configuration, the direction of movement and amount of movement of one control lever determines the rotation direction and rotation speed of the drive motor that drives the drive wheels in forward and reverse directions, and the rotation direction of the servo motor that steers the steered wheels. and its rotation angle are simultaneously controlled. Further, the rotation direction and rotation angle of the servo motor are controlled by the steering control device as follows. In other words, when you move the control lever, the changeover switch changes depending on the direction of movement, and the
The combined resistance value is the resistance value of the high-speed variable resistor or low-speed variable resistor that is varied in conjunction with the rotation of the servo motor, and the resistance value of the operating lever interlocking variable resistor that detects the amount of movement of the operating lever. A corresponding output voltage is generated from the position sensing circuit. An output signal corresponding to the magnitude of this output voltage is generated from the forward rotation control pulse generation circuit or the reverse rotation control pulse generation circuit, and the combination of the servo motor forward rotation signal and the servo motor reverse rotation signal causes the servo motor to is rotated forward, stopped, or reversed by the servo motor rotation control circuit. When the servo motor rotates in either direction,
The resistance value of the high-speed variable resistor or the low-speed variable resistor changes depending on the rotation. Therefore, due to this change in resistance value, the output voltage changes, the combination of signals output from each pulse generating circuit changes, and the rotation of the servo motor is stopped. In this way, the rotation angle of the servo motor is controlled.

(F) Embodiment The electric vehicle of the present invention will be described below using an electric wheelchair shown in the drawings as an embodiment.

In Figure 1, 1 is the body of an electric wheelchair made of metal pipes, 2 and 3 are armrests, 4,
5 is a hand handle, 9 and 7 are footrests, 8
9 is a seat seat, and 9 is a back seat. 10,11
are steering wheels provided on the left and right sides of the front part of the vehicle body 1, and are connected to each other via a connecting rod 12 so as to cooperate with each other. Reference numerals 13 and 14 are support shafts for steering wheels, and one support shaft 13 is connected to a storage battery B ₁ , via pulleys 15 and 16 and a belt 17, as shown in FIG.
It is connected to a servo motor SM whose power source is _B2 , and constitutes a traveling direction control mechanism. VR ₁ is a high-speed variable resistor, and VR ₂ is a low-speed variable resistor, which are connected to the rotating shaft of the servo motor SM via gears 18, 19, 20, pulleys 15, 16, and a belt 17. 21 indicates the pulleys 15 and 16, and the belt 1.
7. This is a front mechanism storage section that stores gears 18, 19, 20, etc. Reference numerals 22 and 23 are driving wheels provided on the rear left and right sides of the vehicle body 1;
Gears, chains, etc. stored in (not shown)
It is connected to the drive motor RM via a speed reduction mechanism consisting of. In addition, the aforementioned traveling direction control mechanism, deceleration mechanism, storage batteries B ₁ , B ₂ , servo motor SM,
Various electrical components such as the drive motor RM are mounted on the vehicle body 1 located below the seat 8. Reference numeral 25 denotes an operation unit for controlling the drive motor RM and servo motor SM, which includes a group of switches operated directly by the operation lever 26, and electric parts such as a variable resistor VR ₃ linked to the operation lever, making it convenient for operation. It is installed in a position close to the armrest 3 as shown in FIG.

Next, the operation section 25 will be explained based on FIG.
The operating lever 26 has an inverted U-shaped fitting 27 at its base end.
is fixed to the metal fitting, and is rotatably supported by a cam 29 via a pin 28 passing through the metal fitting in a left-right direction.
Further, the cam 29 is pivotally supported by a pin 31 on the side wall of the frame 30 so as to be freely rotatable in the front and rear direction. Further, the pin 31 has two position setting metal fittings 32 and 33 of the same type pivoted so as to be arranged symmetrically at the center, one end of which abuts another pin 34 from the side wall, and the other. The ends are connected to each other by a spring 35 and are in contact with the upper part of the cam 29, and the spring 35 always maintains the control lever 26 in a fixed position, that is, in a neutral position with respect to the longitudinal direction. There is. Further, the operating lever 26 has another inverted U-shape equipped with a large spur gear 37 provided to mesh with a horizontal gear 36 provided on the shaft of an operating lever interlocking variable resistor VR ₃ fixed to the side wall of the frame 30. Mold fittings 3
It is loosely fitted into the groove 38a of No.8. The inverted U-shaped metal fitting 38 is pivotally supported on the side wall of the frame 30 via pins 39 and 40 so as to be rotatable in the left-right direction. Further, the one pin 40 has two position setting metal fittings 41 and 42 of the same type pivoted so as to be arranged symmetrically in the center, as described above, and one end of the metal fittings is embedded in the side wall. In addition to contacting the pin 43 implanted in the inverted U-shaped fitting 38, the other ends are connected to each other by a spring 45, so that the operating lever is always in a fixed position. 26
is designed to be held in a neutral position with respect to the left and right direction. Switch groups SW ₄ to _{SW 9} are connected to the cam 29
The frame 30 faces the operating surface of the frame 30 and is operated appropriately.
is fixed.

Here, the operating lever 2 of the operating section 25 shown in FIG.
The relationship between the position 6 and the operating state of the electric wheelchair will be briefly explained in advance. FT,
FTH, FS, and FL are operated by operating lever 2 in the order of forward speed.
6 position, N indicates the stopped state, RTH, RS,
RL indicates the position of the operating lever 26 in reverse high speed order. Also, LT indicates a left turn, S indicates a straight ahead, and RT indicates a right turn. When the operating lever 26 is operated in the front-back direction, the cam 29 causes the switch group SW ₄ to
SW ₉ is activated to control the speed of drive motor RM. Furthermore, if the operating lever 26 is operated to the left or right, the operating lever interlocking variable resistor VR ₃ is activated, the servo motor SM is driven, and the steering wheel 1 is operated.
0 and 11 are rotated to the left or right, and the electric wheelchair is in a state where it can turn. By tilting the operating lever 26 to any position forward, backward, left, or right in this manner, the electric wheelchair can be freely moved in any direction.

FIG. 5 shows an electronic control circuit diagram for controlling the rotation of the drive motor RM and the servo motor SM, and both circuits are constructed by connecting both terminals A and B.

This electronic control circuit consists of a power supply circuit, a stop braking circuit, a drive motor rotation control circuit, a position detection circuit, two pulse generation circuits _A and _B , a servo motor rotation control circuit, and two delay circuits _A and _B. , the position detection circuit, the two pulse generation circuits _A and _B , the servo motor rotation control circuit, and the two delay circuits _A and _B constitute a steering control device. Each circuit will be described in detail below based on illustrated examples. Regarding the symbols of common elements, transistor is Tr, switch is SW, fixed resistor is R, variable resistor is VR, capacitor is C, diode is D, respectively Tr ₁ , Tr ₂ , etc., or
Displayed with subscripts such as SW ₁ , SW ₂ , etc.

The power supply circuit includes two storage batteries B ₁ and B ₂ configuring the DC power supply, a charging terminal CT connected to a charger (not shown), and selective connection between the driving side a ₁ and the charging side b ₁ . Get main switch SW ₁ , breaker
Consists of BK. Furthermore, the main switch
SW ₁ is interlocked with operation/charging selector switch SW ₂ , which will be described later.

The stop control circuit also includes an operation/braking selector switch that can selectively connect the driving side A ₃ and the braking side B ₃ .
It consists of SW ₃ and a coil L for energizing the electromagnetic brake of the drive motor RM.

Then, when main switch SW ₁ is turned on to charging side b ₁ and a charger is connected to charging terminal CT, the storage battery
B ₁ and B ₂ are charged individually, and the power supply to the load circuits below the stop braking circuit is cut off. Next, when the main switch SW ₁ is turned on to the operation side a ₁ , the voltage of the storage batteries B ₁ and B ₂ connected in series will be applied to the load circuit below the stop braking circuit, and the operation braking changeover switch SW ₃ will be turned on. When the power is supplied to the driving side _a3 , power is supplied to the load circuits below the drive motor rotation control circuit, and the circuit becomes operational. If the braking side _b3 is applied, the electromagnetic brake energizing coil L is energized and the electromagnetic brake is applied, creating a state suitable for stopping on a slope or the like. The safety of the electric wheelchair is ensured because the electromagnetic brake operates regardless of the state of breaker BK.

Here, the operating configuration of the electromagnetic brake equipped on the drive motor RM will be explained based on an embodiment shown in FIG. 6. Reference numeral 46 denotes a case of the drive motor RM, and a cover 49 made of a magnetic material and having a boss 47 at the center and a rotation prevention protrusion 48 is screwed onto the case. 50 is the drive motor RM
This is a brake disc made of magnetic material fixed to the shaft 57 of. Reference numeral 52 denotes a core to which an electromagnetic brake energizing coil L is attached and a groove 53 is formed to fit into the detent projection 48. This core 52 is fixed to the boss 47 and faces the brake disk 50 with a small gap. are doing. When the electromagnetic brake energizing coil L is energized, the core 52 attracts and moves the brake disc outer frame 55 which is normally located at the position of the brake disc 50 by the spiral spring 54, and the core 52 and the brake disc outer frame 55 are moved. The structure is such that the rotation of the drive motor RM is stopped by frictional force.

Next, the drive motor rotation control circuit uses a so-called transistor chopper circuit, which includes two PNP transistors Tr ₁ and Tr ₂ , two diodes D ₁ and D ₂ , and seven fixed resistors. R ₁ to R ₇ , one capacitor C ₁ , and an oscillation section consisting of a speed changeover switch SW ₄ interlocked with the operating lever 26, two NPN transistors Tr ₃ and Tr ₄ , two diodes D ₃ , D ₄ , three fixed resistors R ₈ to R ₁₀ , forward/reverse changeover switch SW ₅ linked to the operating lever 26 ,
When operating in conjunction with SW ₆ , speed changeover switches SW ₇ and SW ₈ , and main switch SW ₁ , on the a ₂ side,
It consists of an operation/charging selector switch _SW2 that is turned on to the _b2 side during charging.

First, set the operation/braking selector switch SW ₃ to the driving side.
Add to a ₃ . The operating lever 26 is normally biased by springs 35 and 45, and is set to N (stop) in Fig. 4.
The switch groups SW ₄ to _{SW 9} , which are located at the intersection of and S (straight ahead) and are interlocked with the operating lever 26 at this time, are respectively b ₄
Since the power is applied to the ~ _b9 side, the drive motor RM is in a state where dynamic braking is activated with the fixed resistor _R9 as a load. Now tilt the control lever 26 forward and FL
(1st forward speed), the cam 29 turns the forward/reverse changeover switch _SW5 to the _a5 side, and as the capacitor _C1 is charged and discharged, the transistor _Tr1 is turned on.
When ON, each transistor Tr ₂ , Tr ₃ , Tr ₄ is
OFF, when transistor Tr ₁ is OFF, each transistor Tr ₂ , Tr ₃ , Tr ₄ repeats the ON state, that is, the oscillation part oscillates, an intermittent current flows through the drive motor RM, and the drive motor RM moves at a certain speed. The electric wheelchair rotates in the forward direction with
9 turns the speed changeover switch SW ₇ to the a ₇ side, so that the voltage drop caused by the fixed resistor R ₉ disappears, the rotational speed of the drive motor RM increases, and the speed of the electric wheelchair increases.

Next, when the operating lever 26 is further pushed down to the FTH (3rd forward speed) position, the speed selector switch SW ₄ is
Since the low resistance value of fixed resistor _R2 is set to be smaller than the resistance value of fixed resistor _R3 , the oscillation period of the oscillator changes and the conduction time of transistor _Tr4 becomes longer _. As a result, the rotational speed of the drive motor RM further increases, and the speed of the electric wheelchair further increases.

Next, push down the operating lever 26 further to FT (forward 4
When the speed selector switch SW ₈ is set to the a ₈
Both ends of transistor Tr ₄ are short-circuited, and storage batteries B ₁ and B ₂ are connected to drive motor RM.
The full voltage is applied and the electric wheelchair rotates at full speed, reaching its maximum speed. The diode _D3 connected in the opposite direction between the emitter and collector of the transistor _Tr4 is
The storage batteries B ₁ and B ₂ and the drive motor RM form a series closed circuit, and when going down a slope, etc., the speed changeover switch SW ₈ is automatically switched off when the transistor Tr ₄ is turned OFF even if it is not turned to the A ₈ side. The dynamic braking is activated to prevent the electric wheelchair from overspeeding, and
It is also used to protect against reverse voltage of transistors Tr ₃ and Tr ₄ . Further, the diode _D4 is a flywheel diode that allows current to flow due to the back electromotive force of the drive motor RM generated when the chopper circuit is cut off.

Next, when moving the electric wheelchair backwards, move the operating lever 26 backwards to RL (reverse 1st speed) or RS (reverse 2nd speed).
speed) and RTH (3rd reverse speed), the forward/reverse selector switch _SW5 is switched to the _b5 side, and the other forward/reverse selector switch _SW6 is switched to the _a6 side, and the drive motor
The RM only rotates in reverse, and the other circuit operations are as in the case of forward rotation, with speed changeover switches SW ₄ and SW ₇ operating. However, when reversing, the speed selector switch SW ₈ is not activated and the speed is limited to 3rd gear.

Next, the position detection circuit includes a high-speed variable resistor VR ₁ that is linked to the servo motor SM, a low-speed variable resistor VR ₂ , and an operating lever interlocking variable resistor VR ₃ that is linked to the operating lever 26. Equipment VR ₁ ~
Fixed resistors R ₁₁ to _{R 16} connected to both ends of VR ₃ , and fixed resistors R ₁₇ and R ₁₈ connected in series to these parallel circuits, even if the left and right tilt angles of the operating lever 26 are the same. It is composed of a changeover switch SW ₉ that switches between a high-speed variable resistor VR ₁ and a low-speed variable resistor VR ₂ that are linked to a servo motor SM so as to change the rotation radius according to the speed of the electric wheelchair.

Furthermore, as a pulse generation circuit V _A for normal rotation control,
Here, two NPN type transistors Tr ₅ , Tr ₆ ,
8 fixed resistors R ₁₉ , R ₂₆ , 1 capacitor
It uses a Schmitt trigger circuit consisting of _C2 . Similarly, the reverse control pulse generation circuit V _B includes two NPN transistors Tr ₇ ,
A Schmitt trigger circuit consisting of Tr ₈ , eight fixed resistors R ₂₇ to R ₃₄ , and one capacitor C ₃ is used.

The pulse generation circuit V for forward rotation control and reverse rotation control
_A and _VB have different trigger voltages by changing the resistance values of the corresponding fixed resistors R ₂₁ and R ₂₉ , etc. That is, the trigger voltage e _A of the forward rotation control pulse generation circuit V _A and the trigger voltage e _B of the reverse rotation control pulse generation circuit V _B are set, and e _A is set larger than e _B here. In addition, both pulse generation circuits V _A ,
Figure 7 shows the relationship between the input and output voltages of _VB . Therefore, each variable resistor VR ₁ to
Each pulse generation circuit V changes depending on the operation of VR ₃
The states of the input voltage ei to _A and _VB are [1] (ei) < (e _B ) (reverse rotation) [2] (e _B ) < (ei) < (e _A ) (stop) [3] Three states are possible: (ei) > (e _A ) (forward rotation). Correspondingly, three states appear in the servo motor control circuit described below. The servo motor SM rotates forward in state [3], stops in state [2], and rotates in reverse in state [1].

The servo motor rotation control circuit is a servo motor
4 NPN type transistors to drive SM
Bridge circuit consisting of Tr ₉ to Tr ₁₂ , two PNP transistors Tr ₁₃ and Tr ₁₄ and one fixed resistor R ₃₅
One amplifier section of the bridge circuit consisting of one
The other amplifier section of the bridge circuit consists of a PNP transistor Tr ₁₅ , and six diodes D ₅ ~
D ₁₀ and four fixed resistors R ₃₆ to R ₃₉ .

Therefore, the changeover switch SW ₉ is connected to the operation lever 26.
When is in the position for low speed operation such as N (stop) and FL (first forward speed), it is applied to the b ₉ side, and during high speed operation of FT (fourth forward speed), it is applied to the a ₉ side, and the high speed variable Resistor VR ₁ or low speed variable resistor VR ₂
The input voltage ei to each pulse generation circuit V _A , V _B is set by the combined resistance value of the variable resistor VR ₃ and the operating lever interlocking variable resistor VR 3 . The state in which the steered wheels 10 and 11 are stopped corresponds to the state in which the input voltage ei to each pulse generation circuit _A and _VB is in the above-mentioned state [2]. In other words, in this state, transistor Tr ₅ is OFF and transistor Tr ₆ is OFF.
ON, transistor Tr ₁₃ is ON, transistor Tr ₁₄
is OFF, transistors Tr ₉ and Tr ₁₀ of the corresponding bridge circuit are both OFF, transistor Tr ₇ is ON, transistor Tr ₈ is OFF,
Transistor Tr ₁₅ is OFF, and the corresponding transistors Tr ₁₁ and Tr ₁₂ of the bridge circuit are both OFF.
It becomes OFF, and the transistor Tr ₉ of the bridge circuit
Since all Tr ₁₂ are in the OFF state, power is not supplied to the servo motor and it is in a stopped state.

Now, I'm trying to turn the control lever 26 to the right.
When tilting to the right, the sliding contact piece of the variable resistor VR ₃ linked to the operation lever slides toward the fixed resistor R ₁₅ , and the input voltage ei increases to the state [3] and the base of the transistor Tr ₅ . The potential increases and the transistor
Tr ₅ is switched ON. Then, the transistors Tr ₉ and Tr ₁₀ of the bridge circuit are turned ON, and the servo motor starts rotating in the reverse direction, directing the steered wheels 10 and 11 to the right. When the steering wheels 10, 11 change direction, the high speed variable resistor VR ₁ is connected via the support shaft 13 and gears 18, 19, 20 as shown in FIG.
Alternatively, the sliding contact piece of the low-speed variable resistor VR ₂ slides toward the fixed resistor R ₁₂ or R ₁₄ , and when a certain point is reached, the input voltage ei becomes the state of [2] above, and the servo Motor SM stops rotating and steering wheel 1
0 and 11 stop at that position. Conversely, when you want to change the direction to the left, tilt the operating lever 26 to the left and the sliding contact piece of variable resistor VR ₃ will slide toward fixed resistor R ₁₆ , and the input voltage ei will become lower. 1], the base potential of the transistor Tr ₇ falls, and the transistor Tr ₇ is turned off. Then, transistors Tr ₁₁ and Tr ₁₂ of the bridge circuit are switched ON, and the servo motor SM starts rotating in the forward direction.
Point 0 and 11 to the left. Then, as when changing the direction to the right as described above, use the high-speed variable resistor VR _1.
Alternatively, the sliding contact of the low-speed variable resistor VR ₂ slides toward the fixed resistor R ₁₁ or R ₁₃ , and the input voltage
When ei becomes [2], the servo motor SM stops rotating and the steered wheels 10 and 11 stop at that position.

By the way, depending on the angle at which the operating lever 26 is tilted left or right, there is a variable resistor that is linked to the operating lever.
The sliding amount of the sliding contact piece of VR ₃ changes, and this determines the initial value of the input voltage ei, so the input voltage ei
The amount of sliding of the high-speed variable resistor VR ₁ or the low-speed variable resistor VR ₂ linked to the servo motor SM until it reaches the state [2], that is, the servo motor SM
The rotation angle is proportional to the angle at which the operating lever 26 is tilted. That is, the steering wheels 10, 11 change direction in proportion to the angle at which the operating lever 26 is tilted left or right, thereby controlling the amount of steering of the electric wheelchair.

Here, each variable resistor VR ₁ of the position detection circuit
Regarding VR ₃ , to explain in more detail from the relationship with the input voltage ei of both pulse generating circuits V _A and V _B , the variable resistor VR 3 linked to the operating lever 26 is linked to the servo motor SM rather than the variable resistor VR ₃ linked to the operating lever 26. It is desirable to increase the amount of change in voltage produced by the high-speed variable resistor VR ₁ or the low-speed variable resistor VR ₂ . By doing this, the operating lever 26
Even if _the variable resistor VR ₃ interlocked with the operation lever is _used over the entire range, each pulse generating circuit _V , _VB can be kept in the state [2] at all times, and a short-circuit current can flow to prevent burnout of each of the variable resistors VR ₁ to VR ₃ and seizure of each sliding contact piece. Also, the high speed variable resistor VR ₁ is better than the low speed variable resistor VR ₂ .
It is necessary to increase the amount of change in voltage caused by. By doing this, even if the angle at which the operating lever 26 is tilted left and right is the same,
At high speeds, the range of change of the steering wheels 10 and 11 driven by the servo motor SM is small, and at low speeds the range of change increases, so there is no risk of sharp turns at high speeds, allowing safe driving, and at low speeds. In this case, it is possible to obtain an electric wheelchair with excellent running performance such as the ability to turn in a small radius.
By the way, _the servo motor
The amount of change in voltage generated by the high-speed variable resistor VR ₁ or the low-speed variable resistor VR ₂ linked to SM is increased, and the high-speed variable resistor VR ₁ is larger than the low-speed variable resistor VR ₂ . In order to increase the amount of voltage change caused by each variable resistor VR ₁ to VR ₃ and the fixed resistor R ₁₁ to _{R 16} across
_{The relationship between the resistance values of _ _} ), or as shown in Fig. 2, use the same variable resistors VR ₁ and VR ₂ , and use separate shafts, and set the number of teeth of the gear 18 that drives the high-speed variable resistor VR ₁ . Even if the number of teeth is smaller than that of the gear 19 that drives the low-speed variable resistor VR ₂ , that is, the high-speed ratio of the high-speed variable resistor VR ₁ is made larger than that of the low-speed variable resistor VR ₂ , the same result can be obtained. Effects can be obtained. Here, it is obvious that a known variable impedance element, such as a photoelectric element or an inductance element, can be used as appropriate in place of each of the variable resistors _VR1 to _VR3 .

Note that the diodes D ₅ to D ₁₀ in the servo motor rotation control circuit are for surge absorption, and protect each transistor Tr ₉ to _{Tr 12} of the bridge circuit.
Diode D ₇ is fixed resistor with servo motor SM
R ₃₈ , R ₃₉ and the diode D ₁₀ form a closed circuit with the servo motor SM and the fixed resistors R ₃₆ and R ₃₇ , and the transistors Tr ₉ to Tr ₁₂ are turned off and the steering wheels 10 and 11 are turned off. When the servo motor SM is about to stop, each fixed resistor R ₃₆ , R ₃₇ or
Dynamic braking works with R ₃₈ and R ₃₉ as loads, steering wheel 1
Stop 0 and 11 quickly.

Furthermore, the reason why a Schmitt trigger circuit is used for the input of the bridge circuit transistors Tr ₉ and Tr ₁₀ and the transistors Tr ₁₁ and Tr ₁₂ that control the rotation of the servo motor SM is to improve the startup of the transistors Tr ₉ to Tr ₁₂ . The reason why two Schmitt circuits are used is because a combination of three types of signals is required to rotate the servo motor SM in reverse, stop, and forward. In order to keep the steering condition stable, the hysteresis of the Schmitt trigger circuit should be minimized and the difference between the two trigger voltages should be minimized.
It is desirable to keep (e _A )−(e _B ) | as small as possible.

Next, the delay circuit _A for preventing over-rotation due to the inertia of the servo motor SM consists of two NPNs.
It consists of type transistors _Tr16 , _Tr17 , one PNP type transistor _Tr18 , two diodes _D11 , _D12 , one capacitor _C4 , eight fixed resistors _R40 to _R47 , and Delay circuit _B includes two NPN transistors Tr ₁₉ and Tr ₂₁ , one PNP transistor Tr ₂₀ , two diodes D ₁₃ and D ₁₄ , one capacitor C ₅ , and eight fixed resistors R Consists of ₄₈ ~ R ₅₅ .

When the electric wheelchair turns left and right, these delay circuits _A and _B intermittently supply current to the servo motor SM just before the servo motor SM stops, thereby preventing overshoot of the steering wheels 10 and 11 due to the inertia of the servo motor SM. In other words, in order to make the displacement of the steered wheels respond as accurately and quickly as possible to the operation of the operating lever 26, it is provided to obtain an electric wheelchair with excellent operability.

That is, when the steering wheels 10 and 11 rotate clockwise, the input voltage ei of each pulse generation circuit V _A and V _B is in the state [3], and the transistor Tr ₁₄ of one amplifier section of the servo motor rotation control circuit is turned ON. As a result, _the capacitor C4 is charged through the diode _D11 , fixed resistors _R40 , _R41 , and a time constant determined by the capacitor _C4 , and the base potential of the transistor _Tr16 rises, turning the transistor _Tr16 ON. Then, the transistor Tr ₁₇ is turned OFF, the transistor Tr ₁₈ is turned OFF, and the input voltage ei of each pulse generation circuit V _A and V _B is lowered by the forward voltage drop of the diode D ₁₂ .
Next, the servo motor SM rotates in the reverse direction and the steering wheel 1
As the direction of 0 and 11 changes, the servo motor
The high-speed variable resistor VR ₁ or the low-speed variable resistor VR ₂ linked to SM slides to lower the input voltage ei of each pulse generation circuit V _A , V _B , and when the state [2] is reached, the servo motor Transistors Tr ₉ and Tr ₁₀ of the rotation control circuit are turned OFF, and the servo motor SM
No current will flow through. However, when the input voltage ei reaches the state shown in Fig. 7 [2], the transistor Tr ₁₆
is OFF, transistor Tr ₁₈ is ON, both ends of diode D ₁₂ are shorted, and each pulse generating circuit V _A ,
As a result of the input voltage ei to V _B becoming higher, the input voltage ei
is again in the state shown in Figure 7 [3] and the transistor
Tr ₉ and Tr ₁₀ are turned on and current flows to servo motor SM. By repeating this oscillation operation, an intermittent current flows through the servo motor SM, but the sliding contacts of the high-speed variable resistor VR ₁ or the low-speed variable resistor VR ₂ gradually slide. , the rotation of the servo motor SM gradually attenuates, and the input voltage ei of each pulse generating circuit V _A , V _B reaches a more stable region in the state [2], and finally the servo motor
The SM comes to a complete stop and the steering wheels 10 and 11 stop.

Conversely, when the steering wheels 10 and 11 are rotating to the left, the transistor Tr ₂₁ is activated as the capacitor C ₅ is charged and discharged just before the servo motor SM stops, just as when the steering wheels 10 and 11 are rotating to the left.
By repeating the ON/OFF oscillation operation, the input voltage ei changes, the power supply to the servo motor SM is interrupted, and the rotation of the servo motor SM gradually attenuates and stops.

When the potential of the diodes D ₁₁ and D ₁₃ rises as the capacitors C ₄ and C ₅ are charged, the current flows backwards and the diodes D 11 and D 13 flow backward to each transistor Tr ₉ to Tr ₁₅ of the servo motor rotation control circuit.
This is provided to prevent the system from malfunctioning.

(G) Effects of the Invention The present invention provides a variable resistor for high speed or low speed by switching between a high speed variable resistor and a low speed variable resistor using a changeover switch that is operated in conjunction with the movement of the operating lever in the front and back direction. The rotation angle of the servo motor is made small at high speeds and large at low speeds by changing the resistance value of the resistor and the operating lever interlocking variable resistor, thereby enabling safe running in direction control of the electric vehicle.

Furthermore, the running control of the electric vehicle, such as forward, backward, clockwise, and counterclockwise rotation, can be easily controlled by operating a single control lever.

[Brief explanation of the drawing]

The figures show an example in which the electric vehicle of the present invention is applied to an electric wheelchair. Figure 1 is a partially cutaway perspective view of the electric wheelchair, and Figure 2 is an enlarged view of the main parts of the front mechanism storage section. , Fig. 3 is an enlarged partially cutaway perspective view of the main part of the operating section, Fig. 4 is a diagram for explaining the relationship between the operating lever and each control device, Fig. 5 is an electronic control circuit diagram, and Fig. 6 7 is a sectional view of the electromagnetic brake portion of the drive motor, and FIG. 7 is a diagram showing the relationship between input and output voltages of the pulse generating circuit. 1... Vehicle body, 10, 11... Steering wheel, 22,
23... Drive wheel, 25... Operating unit, B ₁ , B ₂ ...
…Storage battery, SM…Servo motor, RM…Drive motor,…Drive motor rotation control circuit,…
Steering control device, 26... operating lever,... position detection circuit, V _A , V _B ... pulse generation circuit,...
Servo motor rotation control circuit, _A , _B ...delay circuit, SW ₉ ...changeover switch, VR ₁ ...variable resistor for high speed, VR ₂ ...variable resistor for low speed, VR ₃ ...variable resistor linked to operation lever vessel.

Claims (1)

[Scope of Claims] 1. A power source, drive wheels and steering wheels provided on the vehicle body, a drive motor that drives the drive wheels in forward and reverse directions using the power source, and a drive motor rotation that controls forward and reverse rotation of the drive motor and its rotation speed. A control circuit, a servo motor that steers a steering wheel, a steering control device that controls forward and reverse rotation of the servo motor and its rotation angle, a rotation direction and rotation speed of a drive motor, and a rotation direction and rotation angle of a servo motor. The drive motor rotation control circuit has a rotation control circuit that switches in response to the movement of the control lever in the forward and backward directions. The steering control device is equipped with a group of switches that control the direction and rotation speed, and the steering control device includes a control lever interlocking variable resistor whose resistance value changes in conjunction with the movement of the control lever in the left and right direction, and a control lever interlocking variable resistor whose resistance value changes in conjunction with the movement of the control lever in the front and back direction. A position that has a changeover switch that detects the high/low speed of the drive motor associated with the servo motor, and a high-speed variable resistor and a low-speed variable resistor that are switched by the changeover switch and whose resistance value changes in conjunction with the rotation of the servo motor. The servo is activated according to the magnitude of the output voltage from the position detection circuit due to a change in resistance between the detection circuit, the operating lever interlocking variable resistor and the low-speed variable resistor, or the operating lever interlocking variable resistor and the high-speed variable resistor. A pulse generation circuit for forward rotation control that outputs a signal for forward rotation of the motor, a pulse generation circuit for reverse rotation control that outputs a signal for reverse rotation of the servo motor according to the magnitude of the output voltage from the position detection circuit, and a pulse generation circuit for forward rotation control The servo motor is rotated forward or backward based on the signal from either the pulse generation circuit or the reverse control pulse generation circuit, and is stopped when no signal is input from either pulse generation circuit. Equipped with a servo motor rotation control circuit that performs forward/reverse rotation and stopping of the motor, and a changeover switch that controls the rotation angle of the servo motor to be smaller at high speed rotation than at low speed rotation of the drive motor. An electric vehicle characterized by switching between a variable resistor and a variable resistor.