JP2538289B2 - Electric car - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an electric vehicle in which wheels are driven by a DC commutator motor and electric power is supplied to the DC commutator motor via a relay.
Specifically, it is used for golf carts, electric wheelchairs, transport vehicles, electric vehicles and the like.

(B) Conventional Technology As a technology prior to the present invention, there is an electric vehicle described in Japanese Utility Model Publication No. 61-174968. In some electric vehicles, a current limiting resistor (nichrome wire resistor) is connected in series to an armature of a DC commutator motor for driving wheels, and heat generation from the current limiting resistor is prevented by a heat shield plate.

However, the current limiting resistor is designed so that its temperature rise is within the safe range during normal operation, and the heat shield plate is formed in consideration of changes in the amount of heat generated due to variations in parts, but it does not withstand abnormal heat generation. It is not designed to be.

Abnormal heat generation occurs when contact welding occurs in the relay that controls the energization of the DC commutator motor while power is being supplied, even if the electric vehicle is stopped, power is supplied to the armature and the current limiting resistor. In this case, the electric vehicle will be in a stopped state due to insufficient torque due to brake operation and power supply to only the DC commutator motor armature, and the user will not be able to confirm any abnormality. There is also.

Therefore, there is a technique for issuing an alarm when a failure occurs, as shown in Japanese Patent Publication No. 57-50317, Japanese Utility Model Publication No. 56-11191, and Japanese Utility Model Publication No. 57-7546.

However, since the alarm is immediately issued when there is an abnormality, a user with knowledge can recognize the abnormality, but on the contrary, it causes anxiety to other users.

(C) Problems to be Solved by the Invention The present invention provides an electric vehicle capable of issuing an appropriate alarm to a user when an abnormality occurs in a relay that controls power supply to a DC rectification particle motor for driving wheels. To do.

(D) Means for Solving the Problems The present invention controls the power supply to a wheel drive DC commutator motor in which a current limiting resistor is connected in series to an armature with a relay,
If the relay causes contact welding in the power supply state and the power supply cannot be stopped, the specified operation and stop operation cannot be performed.If the power supply to the armature and the current limiting resistor is not stopped, an alarm is issued as an abnormality. The problem is solved by means of forming the abnormality detecting portion.

The stop operation means an operation of turning off the main switch for stopping the power supply to the control section or an operation of turning off the brake operation or the speed variable operation section.

(E) Action The present invention detects an abnormality and gives an alarm when a stop operation is performed, and as long as the electric vehicle is selected to run even if contact welding occurs while the relay is in the power-supply state, it is particularly useful as an electric vehicle. No alarm is issued because the operation that is considered abnormal is not performed.

(F) Example The present invention will be described by taking the illustrated golf cart 1 as a specific example.

FIG. 1 is a circuit diagram of the golf cart 1, FIG. 2 is a perspective view of the golf cart 1, and FIG. 3 is an operation box body 2 of the golf cart 1.
FIG. 4 is a plan view of the operation box body 2, and FIGS. 5 to 8 are waveform charts for explaining the control of the wheel drive DC commutator motor M by the variable speed operation portion 3.

The golf cart 1 is formed by combining and connecting pipes to form a main body frame 4, and a motor M for a wheel drive DC commutator, a storage battery B, a control unit CT and the like are attached to a lower portion of the main body frame 4, and each portion is a main body cover 5 It is covered so as to prevent water. The control unit CT is a circuit portion on the right side, which is divided by the dashed-dotted line in the center of FIG. Drive wheels 6 are pivotally supported on the lower rear portion of the body frame 4, and the drive wheels 6 are driven by a motor M. Steering wheels 7 are supported on the lower front portion of the body frame 4. A golf bag mounting portion 8 is formed on the lower front portion of the body frame 4, and a golf bag support 9 is formed on the upper front portion of the body frame 4. A handle 10 is provided on the upper rear portion of the main body frame 4, and the operation box body 2 is attached to the center of the handle 10. A brake lever 11 is formed on the handle 10. Pulling the brake lever 11 onto the handle 10 operates a mechanical brake (not shown) via the wire 12 to prevent the drive wheels 6 from rotating. The brake switch SW ₂ is also interlocked with the operation of the brake lever 11, and the brake switch SW ₂ is opened when the brake lever 11 is attracted to the handle 10 to apply a brake. In the operation box body 2, the circuit part on the left side divided by the one-dot chain line in the center of FIG.
RM is installed.

The operation box body 2 includes an upper wall 13 formed of synthetic resin, and a box portion 14 formed of sheet metal and having an upper surface opening closed by the upper wall 13. A hanging rib 15 is formed around the upper wall 13,
15 is covered on the outer side of the upper edge of the box portion 14, and the two are connected by a screw 16. A shaft supporting portion 19 is formed at the center of the upper wall 13 by cylindrical portions 17 and 18 which continuously project from the outer surface and the inner surface of the upper wall 13. An operation shaft 20 is inserted and supported by the shaft support portion 19. Cylindrical part of operating shaft 20
A rotary operation knob 21 is fixed to an upper end portion protruding from 17, and an operating body 22 is fixed to a lower end portion protruding from the tubular portion 18. A circuit board 23 is mounted above the lower end of the tubular portion 18 on the inner surface of the upper wall 13, that is, above the lower end of the shaft support portion 19. The circuit board 23 has a main switch SW on the speed variable operation section side RM shown in FIG.
Parts other than ₁ and brake switch SW ₂ are attached and wired. The main switch SW ₁ is attached to the box portion 14 so that its operation portion is exposed. _{S 0, S 2, S 3} , S 4, S 5, S 6, S 7, S 8 in reed switch, it constitutes a setting unit which performs stop of the motor M, the governor and at and away of the magnetic material It is a magnetic sensitive element that is cut. Reed switches S ₀ , S ₂ ... S ₈ are connected in series with resistors R ₁ , R ₂ , R ₃ ,
R ₄ , R ₅ , R ₆ , and R ₇ are connected.

The operating body 22 is an operating plate 24 made of a synthetic resin disc body.
And a magnetic body 25 mounted on the outer peripheral upper surface of the operation plate 24. The upper surface of the operation plate 24 is formed with a plurality of recesses 27 with which an engaging body 26 that holds the operation plate 24 at a proper rotation position is engaged.
The engagement body 26 is biased by a spring 28 and is stored in the storage portion 29 of the upper wall 13. With this structure, nine recesses 27 are formed. Operation board
The holding position of 24 by the engagement body 26 is the position where the magnetic body 25 corresponds to the reed switches S ₀ , S ₂ ... S ₈ and the position corresponding to the virtual switch S ₁ between the reed switches S ₀ and S ₂ . Further, a pointer portion 30 is formed on the rotary operation knob 21, a holding position of the operation plate 24 is shown, and a display plate 31 showing the set state by the pointer portion 30 is attached to the upper surface of the upper wall 13. . As shown in FIG. 4, the display plate 31 displays a display showing nine setting positions and a motor M.
And the character display showing the state of.

In the display plate 31, the tubular portion 17 has an insertion hole at the center, and the rotary operation knob 21 covers the tubular portion 17.

The golf cart 1 is used outdoors, and when used in rainy weather, the operation box body 2 gets wet with water, but the water dropped on the upper wall 13 flows down from the surroundings without entering the box portion 14. The operation shaft 20 is pivotally supported by the tubular portion 17 so that water is transferred to the tubular portion 17.
Cannot be raised and prevents water from entering through the shaft support portion 19. When the water rises in the tubular portion 17 due to the wind and water enters the box portion 14 through the gap between the operation shaft 20 and the shaft support portion 19, the inflowing water flows on the upper surface of the operation body 22 and flows down. As a result, the infiltrated water does not reach the circuit board 23 located above the operating body 22, and good electrical insulation is maintained.

It should be noted that no electrical component is attached to the box portion 14 below the operating body 22, and the main switch SW ₁ is naturally attached to the upper portion of the box portion 14. A drain hole for removing water that has entered the box portion 14 is formed in the lower portion of the box portion 14.

A lead wire 32 that connects the circuit board 23 to the control unit CT is wired in the handle 10. The lead wire 32 includes six wires and seven ground wires which are crossed by the alternate long and short dash line in FIG. 1, and one wire for the battery checker shown in FIG. 4 although not shown in the circuit of FIG. There is.

The electric circuit of the golf cart 1 is a resistor as shown in FIG.
The capacitor, diode, transistor, comparator, relay, EXCLUSIVE OR circuit, and motor M are connected.

The current limiting resistors R ₂₁ and R ₂₂ are connected in series to the armature M _{2 of the} motor M, and the resistor R ₂₁ is short-circuit controlled by the relay contact RS ₂ that is turned on and off by the relay coil RM ₂ of the start compensation relay. To be done. The armature M ₂ and the storage battery B are connected to each other via a relay contact RS ₁ which is cut and inserted by a relay coil RM ₁ of the main relay. A diode is provided in parallel with the shunt coil M ₁ of the motor M.
D ₁₀ is connected, and the current control transistor T ₃ is connected in series to the shunt coil M ₁ . A parallel circuit of diodes D ₇ , D ₈ , and D ₉ is connected to the base terminal of the transistor T ₃ . Diode D ₈ is connected to the output of comparator COP ₁
D ₉ is connected to the output of comparator COP ₂ . The diode D ₇ is connected to the collector terminal of the transistor T ₂ which controls the relay coil RM ₂ via the diode D ₆ . Transistor
A delay circuit consisting of resistors R ₁₆ and R ₁₅ and a capacitor C ₂ is connected to the base terminal of T ₂ . The delay circuit is connected to the storage battery B via the photo coupler FS, the brake switch SW ₂ and the main switch SW ₁ . The relay coil RM ₁ of the main relay and the light emitting element of the photo-bra FS are connected in parallel and connected to the collector terminal of the stall control transistor T ₁ . Resistors R ₉ , R ₁₁ , and R ₁₀ and resistors R ₁ ... R _{7 of the} variable speed operation unit 3 are connected to the base terminal of the transistor T ₁ . The resistors R ₉ and R ₁₀ are connected to the storage battery B via the stabilizing resistor R ₈ and the Zener diode ZD ₁ and the main switch SW ₁ . The connection between the resistors R ₉ and R ₁₀ is connected to the base terminal of the transistor T ₁ , and
Connected to the positive input of comparator COP ₁ . Comparator COP ₁ positive input voltages V ₁ is changed by the operation of the speed variable operation unit 3. The + input of the comparator CPO ₂ is connected between the armature M ₂ and the resistor R _22, and the voltage V ₃ of the resistor R ₂₂ is input. Comparators COP ₁ and COP ₂
Bruno - output from the triangular wave generator A ₂ is the input resistor R ₁₃ and R ₁₄
Is divided and applied. -Input voltage V ₂ of comparator COP ₁
Is set to be larger than the − input voltage V ₄ of the comparator COP ₂ .

The abnormality detection unit A ₁ is formed by connecting two EXCLUSIC VE OR circuits, and its output terminal e is connected via a resistor R ₂₃ to the base terminal of a transistor T ₄ which controls the alarm generator SP. By connecting the input to resistors R ₂₄ , R ₂₅ , R ₂₆ , R ₂₇ , R ₂₈ , R ₂₉ , the input terminal a is changed from the brake switch SW ₂ to the control unit C.
It is connected to the T side, the input terminal b is connected between the relay coil RM ₁ and the transistor T _1, and the input terminal d is the relay contact RS.
_{When 1} disconnects from the armature M _2, it is connected to its moving contact.

Next, the operation of the motor M will be described. The states of the switches SW ₁ and SW ₂ , the relay contacts RS ₁ and RS ₂ , and the reed switches S ₀ and S ₂ ... S ₈ shown in FIG. ₁ are that the main switch SW ₁ of the golf cart 1 is turned off and the brake is applied. The wheels are fixed and the variable speed operation unit 3 is cut off. Therefore, the reed switch S ₀ is turned on and the storage battery B is connected to the input terminal d of the abnormality detection unit A ₁ .

Next, when the main switch SW ₁ and the brake switch SW ₂ are turned on, the reed switch S ₀ is turned on, so that the transistor T ₁ maintains non-conduction and both relay contacts RS ₁ and RS ₂ maintain the current state.

When the rotary operation knob 21 is rotated by one scale, the magnetic body 25 is displaced from the reed switch S ₀ to the position of the virtual reed switch S ₁ , and the reed switch S ₀ is turned off.
Then, the transistor T ₁ becomes conductive, the relay coil RM ₁ is energized, and the relay contact RS ₁ is connected to the armature M ₂ . At this time, the transistor T ₂ is non-conducting for the charging time of the capacitor C ₂ and then the relay coil RM ₂ is energized and the relay contact RS ₂
Close. At this time, the positive input voltage V ₁ of the comparator COP ₁ is larger than the negative input voltage V ₂ as shown in FIG. 5, the diode D ₈ is at a high level, and the transistor T ₃ is always conductive (duty 100).
%), And the motor M rotates at the lowest speed. However until the transistor T ₂ is conducting motor M is started by the series circuit of the resistors R ₂₁ and R _22, ensures even uphill with will be slowly started by driving torque increases You can take off. In addition, since the diode D ₇ is at a high level until the transistor T ₂ becomes conductive, the transistor T ₃ has a duty of 100% regardless of the levels of the diodes D ₈ and D ₉ , so the brake is stopped. When reed switch S ₂ … S ₈ is selected with and the brake is released, transistor T ₃ is always conducted with 100% duty until transistor T ₂ is conducted. It can be carried out. By sequentially switching from reed switch S ₂ to S ₈ , the + input voltage V ₁ becomes smaller, and the high level time of the output of diode D ₈ becomes a little shorter when reed switch S ₂ shown in Fig. 6 is turned on. , The transistor T ₃ is duty
It becomes about 80%, and the motor M is operated at a low speed. Also,
The output of the diode D ₆ is in a state of the reed switch S ₈ is turned ON as shown in FIG. 7, the transistor T ₃ is duty 20
%, And the motor M is operated at the highest speed. However,
The torque decreases as the motor M rotates at a higher speed.

Therefore, FIG. 8 shows the state when traveling uphill at the highest speed. Since the maximum speed that requires a large torque is set when going uphill, the torque is small and the rotation speed decreases due to an increase in the load on the motor M. When the rotation speed decreases, the current in the armature M ₂ increases and the comparator COP ₂
Since the + input voltage V _{3 of the} circuit becomes large and overlaps with the − input voltage V ₄ , the output is generated from the diode D ₉ , the high level time becomes long, and the transistor T ₃ has a duty of about 60%. T ₃ is controlled by the diode D ₉ , and the rotation speed of the motor M changes to the low speed side to increase the torque, so that the vehicle can run smoothly uphill.

Rotary operation knob 21 while using golf cart 1
And the "OFF" of the reed switch S ₀ even if the position disconnection of connection lines L ₁ and ground wire L ₂ to the base terminal of the failure or transistors T ₁ that do not ON sets the virtual reed switch S ₁ if it occurs Golf cart 1
Can keep running at the lowest speed. As a result, the golf cart 1 can be moved to a repairable point, a safe place, and a repair requestable point without abandoning the golf cart 1, and golf can be continued without abandoning. The stop in this state can be performed by operating the brake lever 11.

When the golf cart 1 is running, the abnormality detection unit A ₁ has the output terminal because the input terminals b and d are at a low level and the input terminal a is at a high level because the transistor T ₁ is ON. e becomes high level and the transistor
T ₄ is generator SP will not be in the OFF. When the main switch SW ₁ or the brake switch SW ₂ is turned off, the input terminals a and b are at a low level, the input terminal d is at a high level, the output terminal e is at a high level, and the generator SP does not ring. When the main switch SW ₁ and the brake switch SW ₂ are turned on and the reed switch S ₀ is turned on, the input terminals a, b, d become high level, the output terminal e becomes high level, and the generator
SP does not ring. Therefore, in the golf cart 1 in a normal state, the generator SP does not ring.

In addition, even if the relay contact RS ₁ is welded while being connected to the armature M ₂ , the reed switch is operated by the variable speed operation unit 3.
S _0, that is, a state other than "OFF" is set, by the operation never any change to the normal state in the traveling state where the main switch SW ₁ is also not the brake switch SW ₂ also operated generator SP is sounded Absent.

Next, when the relay contact RS ₁ is welded while being connected to the armature M ₂ , the main switch SW ₁ is turned off or the brake lever 11 is operated to turn off the brake switch SW ₂ or the rotary operation knob 21. When the reed switch S ₀ is turned on by operation, the generator SP sounds. That is, when the above-described operations are performed, the input changes of the input terminals a and b of the abnormality detection unit A ₁ are the same as those in the normal state, and the main switch SW ₁ or the brake switch SW ₂ is turned off to a low level, and the lead switch
The intermediate output terminal C is always at the low level because it is at the high level when S ₀ is ON. On the other hand, since the relay contact RS ₁ is welded, the input terminal d is always at the low level, so the output terminal e is at the low level and the transistor
T ₄ is turned ON, generator SP sounds.

If any of the above-mentioned three or more operations are performed in the state where the contact welding occurs, the shunt coil M ₁ is not energized because the transistor T ₃ is turned off, and the armature M ₂ and the resistor R ₂₁ , R
₂₂ is energized, and the motor M cannot run with zero torque and stops. If this state continues, armature M ₂ , resistance R
₂₁ and R ₂₂ generate abnormal heat and may cause ignition. In particular, in the case of the golf cart 1, the nichrome resistance is used for the resistance R _{21 which} is interposed in order to obtain a sufficient starting torque at the time of start and slowly start without suddenly starting from the viewpoint of assembly, cost and design. It becomes red-hot, and the generator SP sounds only when the situation of this state occurs, to notify the abnormality.

Incidentally, the above-mentioned structure shows a structure which is considered to be the most suitable for the present golf cart to carry out the present invention.
The structure is not limited to this, and various modifications can be made.

(G) Effect of the Invention According to the present invention, a relay is connected to the armature of a DC commutator motor for driving a wheel in series, and even if the relay is welded, an alarm is issued only when the motor is stopped, thereby welding the relay. Thus, when the electric vehicle is in a situation where an accident occurs, the user can be notified that the relay is welded and the accident can be prevented in advance.

[Brief description of drawings]

FIG. 1 shows the present invention, which is a structure used in a golf cart. FIG. 1 is an electric circuit diagram, FIG. 2 is a perspective view, FIG. 3 is a sectional view of an operation box, and FIG. 4 is a plan view of the same. 5 to 8 are waveform charts showing the operation. 1 ... Golf cart (electric car), 2 ... Operation box, 3 ...
... speed variable operation unit, CT ...... control unit, RM ...... speed variable operation unit side, M ...... motor, A ₁ ...... abnormality detection unit, SP ...... generator, SW ₁ ...... main switch, SW ₂ ... … Brake switch.

Claims (1)

(57) [Claims] 1. In an electric vehicle in which a current limiting resistor is connected in series to an armature of a DC commutator motor for driving wheels and a power supply to the DC commutator motor is controlled by a relay, the relay is connected to the DC commutator motor. An electric vehicle that has an abnormality detection unit that causes contact welding in the power feeding state and issues an alarm when the DC commutator motor is stopped.