JPH02290107A - Electric motor car - Google Patents

Abstract

PURPOSE:To allow an electric motor car stably to travel along a steep slope or a gentle slope by outputting a signal through a regenerative current detection circuit to increase motor field current to a motor drive circuit until no detected value exceeds the set value if the regenerative current of a motor exceeds the set value. CONSTITUTION:When a golf cart approaches a downhill slope, it intends to go down the slope due to its tare weight at a speed faster than the set speed and the regenerative current of a motor M increases. When a comparator COP1 in a regenerative current detection circuit 50 inputs regenerative current from a positive input terminal and the regenerative current above gets to not less than a specified value determined by resistances R18, R34 and R35, the comparator COP1 goes down to an L output and a transistor Tr2 is conducting. The positive input voltage of a comparator COP2 in a speed control circuit 45 is then raised, the conducting time of a transistor Tr5 is increased and the field current grows to reduce the rotating speed of the motor M. Regenerative braking greater than that of the set speed is thereby applied to the golf cart, so that the cart can be recovered from a runaway state as quickly as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to electric vehicles such as golf carts, electric wheelchairs, and electric cars.

(Expression) Conventional technology In the past, for this type of electric vehicle, permanent magnets were attached to the downhill start and end points of the electric vehicle's taxiway, and a detection element for the same was installed on the electric vehicle, and two magnets were detected based on the output of this element. Japanese Utility Model Application Laid-Open No. 57-63402 discloses a device in which the drive motors are switched from series connection to parallel connection for deceleration running.

However, in this conventional example, the speed is slowed down regardless of the slope of the downhill slope, so in places with steep slopes, the running speed is high and there is a risk of a dangerous state, that is, a runaway state. The drawback was that the running speed was too slow in areas with gentle slopes.

(C) Problems to be Solved by the Invention The present invention was developed in view of the above-mentioned drawbacks of the conventional technology, and it increases the range of response to downhill slopes, making it possible to run stably on both steep and gentle slopes. The challenge is to provide electric vehicles.

(2) Means for Solving the Problems The present invention provides a wheel drive motor having an armature winding and a field winding, a motor drive circuit that controls the armature current and field current of the motor, Detects the regenerative current of the motor, compares the detected value with a preset set value, and outputs a signal to the motor drive circuit to increase the motor field current when the detected value exceeds the set value. The present invention is characterized by comprising a regenerative current detection circuit.

(e) Effect When approaching a downhill slope, the electric vehicle attempts to descend at a speed faster than the set speed due to its own weight, and the regenerative current of the motor increases. When the regenerative current of the motor detected by the regenerative current detection circuit exceeds the set value, the regenerative current detection circuit outputs a signal to the motor drive circuit to increase the motor field current until the detected value no longer exceeds the set value. Therefore, on a downhill slope with a gentle slope, the output signal from the regenerative current detection circuit stops immediately, so the amount of deceleration is small, and the traveling speed does not become too slow due to excessive deceleration.

Furthermore, on a steep downhill slope, the output signal from the regenerative current detection circuit continues for a long time, and there is no risk of significant deceleration and runaway condition.

(f) Examples Examples of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the following examples.

The present invention will be explained using the illustrated golf cart 1 as a specific example.

1 is a circuit diagram of the golf cart 1, FIG. 2 is a perspective view of the golf cart 1, FIG. 3 is a sectional view of the operation box 2 of the golf cart 1, and FIG. 4 is a plan view of the operation box 2. be.

The golf cart 1 has a main body frame 4 formed by combining and connecting pipe bodies, and a wheel drive motor (hereinafter referred to as motor) M, a storage battery B, a control circuit, etc. are attached to the lower part of the main body frame 4, and each part is connected to the main body frame 4. It is covered with a physical strength bar of 5 to protect it from water. A drive wheel 6 is pivotally supported at the rear lower part of the main body frame 4, and the drive wheel 6 is driven by a motor M. A steering wheel 7 is supported at the front lower part of the main body frame 4. A golf bag mounting portion 8 is formed at the front lower part of the main body frame 4, and a golf bag support 9 is formed at the front upper part of the main body frame 4. The rear upper part of the main body frame 4 is a handle 10, 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. By pulling the brake lever 11 to the handle 10, a mechanical brake (not shown) is applied via the wire 12.
is operated to prevent the drive wheel 6 from rotating. The brake switch SW2 is also operated in conjunction with the operation of the brake lever 11, and when the brake lever 11 is attracted to the handle 10 and the brake is applied, the brake switch SW2 is released.

The operation box body 2 includes an upper wall 13 molded from synthetic resin and a box portion 14 formed from a sheet metal whose upper opening is closed by the upper wall 13. A hanging rib 15 is formed around the upper wall 13,
A hanging rib 15 covers the outer side of the upper edge of the box part 14, and the two are connected by a screw 16. The center of the upper wall 13 forms a shaft support 19 with cylindrical portions 17 and 18 that continuously protrude from the outer and inner surfaces of the earthen wall 13. An operating shaft 20 is inserted through and supported by the shaft support 19. A rotary operating knob 21 is fixed to the upper end of the operating shaft 20 that protrudes from the cylindrical portion 17, and an operating body 22 is fixed to the lower end that protrudes from the cylindrical portion 18. A circuit board 23 is mounted on the lower end of the cylindrical portion on the inner surface of the upper wall 13, that is, above the lower end of the shaft support 19.The main switch SW is mounted on the box portion 14 so that its operating portion is exposed. so, Sll S2, S3,
S4. S5+ S6. S7 and sll are reed switches, which constitute a setting section for stopping and controlling the speed of the motor M, and are magneto-sensitive elements that are turned on and off when a magnetic body approaches or separates. Resistors Rl, R2...S8 are connected in series to the reed switches So, SL, S2...S8. R3, Ra. R%. R
6. R7 and R8 are connected.

The operating body 22 is an operating plate 24 formed of a synthetic resin disc body.
and a magnetic body 25 attached to the upper surface of the outer periphery of the operation plate 24. A plurality of recesses 27 are formed on the upper surface of the operation plate 24, into which engagement bodies 26 that hold the operation plate 24 in an appropriate rotational position are engaged. The engaging body 26 is biased by a spring 28 and the upper wall 1
It is stored in the storage section 29 of 3. In this structure, the recess 27 is 9
Formed individually. The holding position of the operation plate 24 by the engaging body 26 is that the magnetic body 25 is the reed switch SO+ Sll S2, ・
...S. This is the position corresponding to Further, a pointer portion 30 is formed on the rotary operation knob 21, and a display plate 3 that indicates each holding position of the operation plate 24 and indicates the set state by the pointer portion 30.
1 is attached to the upper surface of the upper wall 13. As shown in FIG. 11, the display board 31 is provided with displays indicating nine setting positions and text indicating the status of the motor M.

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

The golf cart 1 is used outdoors, and when the operating box body 2 is used in rainy weather, the operation box body 2 gets wet, but the water falling on the earthen wall 13 flows down without entering the box body 14 from the surroundings. Since the operating shaft 20 is pivotally supported by the cylindrical portion 17, water cannot rise up the cylindrical portion 17, and water is prevented from entering from the shaft support 19. When water rises in the cylindrical portion 17 due to the wind and enters the box portion 14 through the gap between the operating shaft 20 and the shaft support 19, the entered water flows over the upper surface of the operating body 22 and flows downward. As a result, water that has entered the circuit board 23 located above the operating body 22 does not reach the circuit board 23, and electrical insulation is maintained satisfactorily.

Note that no electrical parts are installed in the box part 14 located below the operating body 22, and the main switch SW is naturally located in the box part 1.
It is attached to the top of 4. A drainage hole is formed in the lower part of the box part 14 to drain water that has entered the box part 14.

Next, the electric circuit of the golf cart 1 will be described in detail below based on FIG. 1. The storage battery B is connected to the main switch SW! and is connected to the brake switch SW2 via the constant voltage circuit 41.

42 is reed switch S. , S, . . . S6 and the resistor Rl. The speed of the motor M is set by a switch circuit having R2, . . . R8. 43 is a drive circuit that inputs signals from the brake switch S W 2, the constant voltage circuit 41, and the switch circuit 42; l14 is a drive circuit that inputs signals from the brake switch S W 2, the constant voltage circuit 41, and the switch circuit 42; Duty 1 is applied to the motor M for a determined fixed period of time (0.5 seconds in the example).
Golf cart 1 with a torque guarantee circuit that applies 00% field? Even when the vehicle is located on a downhill slope, the vehicle can be reliably climbed without retreating.

A speed control circuit 45 compares the signals from the drive circuit 43 and the torque guarantee circuit 44 with the output of the triangular wave generator 46, and outputs a signal instructing the rotational speed of the motor M according to the comparison value. A speed control circuit 47 is the drive circuit 43. Signal from and triangle wave generator 4
A soft start circuit that compares the output of 6 and controls the armature current of the motor M when starting the golf cart 1.
At the start of the golf cart 1, a certain period of time determined by the time constant of the capacitor C and the resistor R3 (in this example, 4
seconds), the golf cart is switched from low speed to switch circuit 4.
This is for gradually increasing the speed to the speed set in step 2.

48 is the capacitor C2 when the brake switch SW2 is operated.
This is a braking circuit that outputs a signal that increases the field current of the field winding M1 of the motor M for a certain period of time (2 seconds in this example) determined by the time constant of the resistor R26.
When operating W 2 to stop golf cart 1, ib
Regenerative braking with a larger braking force than the regenerative braking at the speed set by the switch circuit 42 is performed until the mechanical brake is activated, and even when stopping the golf cart 1 on a downhill slope, the regenerative braking is performed until the mechanical brake is activated. In between, golf cart 1
This is to prevent the machine from going out of control due to its own weight.

49 is a motor drive circuit that controls the speed of the motor M based on the signals from the speed control circuit 45 and the soft start circuit 47; 50 detects the regenerative current of the motor M; and the output of the speed control circuit ll5 based on the detected value; When the golf cart 1 is traveling downhill, the regenerative current detection circuit detects an increase in the regenerative current of the motor M, increases the field current of the motor M, and corrects the regenerative braking so that the regenerative braking is further increased. This is to enable the golf cart 1 to recover from a runaway state as quickly as possible.

Next, the operation will be explained.

The states of the switches SW+, SW2, reed switches So, S+...-88 shown in FIG. 1 are as follows: the main switch SW of the golf cart 1 is turned off, the brakes are applied, the wheels are fixed, and the speed is The variable operation section 3 is in a turned off state.

Next, the main switch S W t and the brake switch S
When W2 is turned on, reed switch S is activated. Since the transistor Tr is turned on, the transistor Tr remains non-conductive.

When the rotary operation knob 21 is rotated by one scale, the magnetic body 25 is shifted from the reed switch S0 and moves to the reed switch S1 position, and the reed switch S0 is turned OFF.
becomes. Then, the transistor Tr. , Tr, is conductive;
The torque guarantee circuit 114 is energized and the capacitor. For a certain period of time (0.5 seconds in this embodiment) determined by the time constants of the capacitor C and the resistor R2, an H output is output from the comparator COP4 to the speed control circuit 45, and at this time, the ten input of the comparator COP2 Since the voltage is higher than the single power voltage, it becomes an H output, transistor Trq is always conductive (duty 100%), motor M rotates at the lowest speed and maximum torque, and the vehicle can start reliably even on an uphill slope.0 After 5 seconds have elapsed, the comparator COP4 outputs an output, but since the reed switch S, is ONL, the input voltage of the comparator COP2 is large, and the motor M rotates at low speed and large torque.Reed switch By sequentially switching from S1 to 88, the comparator CO
The input voltage of P2 gradually decreases, and the reed switch S
When s is turned on, motor M is operated at maximum speed. However, the faster the motor M rotates, the smaller the torque becomes.

Also, when starting the golf cart 1, the soft start
Comparator COP5 of circuit 47 is connected to capacitor C3 and resistor R)
The positive input voltage is gradually increased during a certain period of time determined by the time constant of 2 (4 seconds in this example), and the 10 input voltage is compared with the single-power voltage input from the triangular wave generator 46.
Gradually increase the output pulse width. Therefore, the ON time of the field effect transistor FET becomes gradually longer, and a smooth start without sudden start can be performed.

Next, a case where the vehicle travels uphill at high speed will be described. When going uphill, a large torque is required, but when the high speed is set, the torque is small and the load on the motor M increases, causing the rotation speed to decrease. As the rotation speed decreases, the armature current in the armature winding M2 increases, and the input voltage of the comparator COP3 increases, so the portion exceeding the single-power voltage input from the triangular wave generator 46 increases. Tehitsuki COP
The H output from 3 increases, the ON time of the transistor Trs increases, the motor M slows down, the torque increases, and the vehicle can run uphill smoothly.

Next, we will explain the case of driving downhill. When the golf cart 1 approaches a downhill slope, the golf cart 1 attempts to descend the slope at a speed faster than the set speed due to its own weight, and the regenerative current of the motor M increases. The comparator COPI of the regenerative current detection circuit 50 inputs the regenerative current from the ten input terminals, and the regenerative current is applied to the resistor R1e:
When it reaches a predetermined value determined by R34 + R3%,
The comparator COPI becomes an L output and the transistor Tr2 becomes conductive, increasing the input voltage of the comparator COP2 of the speed control circuit 45 and increasing the conduction time of the transistor Tr.
．． The field current is increased and the rotational speed of the motor M is decreased to apply regenerative braking to the golf cart 1 that is greater than the regenerative braking at the set speed, thereby allowing the golf cart 1 to recover from a runaway state as quickly as possible.

Next, we will explain how to operate the brakes. When the brake is applied, the brake switch S W 2 is turned OFF, the transistor Trs is turned OFF, and the inverting element I N V s becomes an H output. Inverting element INV2 for a certain period of time (2 seconds in this example) determined by the time constant of capacitor C2 and resistor R26
input becomes H, the output of the inverting element INV2 becomes L, transistor Tr4 becomes ONL, diode D6 . D?
The output becomes H.

Therefore, the voltage of the comparator COP2 increases, the output pulse width of the comparator CPO2 becomes longer, and the transistor Tr
, the conduction time becomes longer and regenerative braking is applied.

When 2 seconds elapse from application of the brake until charging of capacitor C2 is completed, the output of inverting element IN2 becomes H.
Therefore, the transistor Tr4 is turned off. Furthermore, at the moment the brake is applied, the output of the diode D8 becomes OFF, so the transistor Tr turns OFF and stops energizing the motor M.

Therefore, from the time the brake is operated until the mechanical brake is activated, the golf cart 1 can be decelerated by the braking circuit 48 by regenerative braking that is greater than the regenerative braking at the set speed.

(g) Effects of the Invention As described above, the present invention provides an electric vehicle that can always run at a stable speed regardless of the slope of the downhill slope.

[Brief explanation of drawings]

The drawings all show an embodiment in which the present invention is applied to a golf cart, with Fig. 1 being an electric circuit diagram, Fig. 2 being a perspective view of the golf cart, Fig. 3 being a sectional view of the operation box, and Fig. 4. is the same plan view. M...Wheel drive motor, M1...Field winding, M2
... Armature winding, 49 ... Motor drive circuit, 50.
...Regenerative current detection circuit.

Claims (1)

[Claims] (1) A wheel drive motor having an armature winding and a field winding, a motor drive circuit that controls the armature current and field current of the motor, and a detected value that detects the regenerative current of the motor. and a preset set value, and when the detected value exceeds the set value, the motor drive circuit is provided with a regenerative current detection circuit that outputs a signal to increase the field current of the motor. Characteristic electric vehicles.