JPH0710987Y2 - Electric wheelbarrow - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) The present invention relates to an electric wheelbarrow used on the road such as a shopping car, in particular, an improved battery-driven structure that consumes less power. is there.

(Prior Art) In recent years, the number of large-sized stores such as supermarkets has increased, and many products have been bought at once, and many shopping cars have been used to carry these products to home.

In normal shopping, there is a large range of 2-3 km from the house to the store, and if the baggage is heavy and there are many slopes, the shopping car becomes heavy, which is a heavy labor for a weak housewife and the elderly.

On the other hand, in production sites and the like, electric vehicles that use a battery as a power source are used. However, even if the battery runs out, a spare battery can be directly replaced on the spot, so a small battery was sufficient. .

However, if a shopping car used on a general road is equipped with a battery and is electrically operated, a large-capacity battery must be installed in order to drive on the road for 2-3 km without running out of battery and the battery weight. It will be about 2kg, and the whole body will be 4-5kg.

In addition, conventional shopping cars weigh about 2-3 kg at most, and most of them are two-wheeled vehicles so that they can be easily carried when brought into a bus or train.

When making such a motorcycle electric, it is usually necessary to attach an operation switch such as start and stop to the handle and operate the switch while walking, and a housewife or an old man who is unfamiliar with the machine can drive the car. It is very dangerous to perform such an operation on a public road.

(Problems to be solved by the invention) The present invention eliminates the above-mentioned drawbacks, is easy to operate and is excellent in safety, and further reduces the power consumption by minimizing the frequency of use of the battery to improve the economical efficiency. The present invention provides an electric wheelbarrow with a battery that is smaller and lighter.

[Structure of the Invention] (Means for Solving Problems) The present invention relates to a frame to which a luggage compartment is attached, a handle attached to this frame, and a handle attached to this handle when a forward force is applied. A pressure sensor that detects this pressure, a motor that is driven by a battery, and a motor that is provided between the output shaft of the motor and the gear attached here, or between the reduction gear that meshes with this gear and the wheel drive shaft. A one-way clutch for transmitting the rotational force of the wheel drive shaft to the wheel drive shaft and for transmitting the rotational torque in the backward direction of the wheel drive shaft to the motor, and a motor control mechanism for controlling the rotation of the motor by the detection signal of the pressure sensor. It is a feature.

Further, the present invention is provided with two pressure sensors that detect the pressure when a force is applied to the steering wheel in the forward and reverse directions, respectively, and detects the pressure difference between the two pressure sensors to control the rotation of the motor. A control mechanism may be provided.

Further, a motor stop mechanism may be provided to stop the motor when both pressure sensors simultaneously detect a pressure higher than a specified value.

(Operation) The operation of the present invention will be explained. When the handle is grasped and lightly pushed on a flat road to move forward, between the output shaft of the motor and the gear attached thereto or between the wheel drive shaft and the reduction gear. Since the one-way clutch interposed in the wheel works in the slipping direction, the torque of the wheels is not transmitted to the motor side, and the vehicle can be lightly moved forward even when the motor is not driven.

Further, even if the battery runs out while running on the road, the one-way clutch works in the slipping direction, so that the vehicle can move forward lightly.

When the handle is grasped by hand and pushed forward, the pressure sensor detects this pushing force, an output proportional to this pressure is input to the motor control mechanism, and from there a control signal is output to the motor and the motor is It is driven by a force proportional to the pushing force.

When the motor rotates, this drive torque is transmitted to the reduction gear via the gear attached to the output shaft, and the one-way clutch is in the connected state, so it is transmitted to the wheel drive shaft and combined with the force pushing the steering wheel to move the vehicle body. You can move forward.

Therefore, when the road is flat or the load is light, the pressure applied to the pressure sensor is small, and the amount of electricity supplied to the DC motor is proportionally small, and the vehicle can be advanced almost manually.

When the load is heavy or when you are going uphill, the force to push the handle becomes stronger, and the pressure sensor also exerts a large pressure to increase the amount of electricity to the motor and generate a large driving torque, so you can keep the body force constant. You can push with to move forward.

If you stop while walking, the pressure applied to the pressure sensor becomes zero, so the motor drive stops and the vehicle body stops.

If the vehicle stops due to tiredness on the way uphill, the wheel drive shaft tries to rotate backward due to the force of the vehicle body that tries to lower due to its own weight, but the wheel drive shaft rotates only when a reverse force is applied. Since the one-way clutch for transmitting torque is provided, the motor is directly connected to the motor.

Therefore, the field permanent magnet inside the motor that is not in the energized state acts as a brake due to the suppression torque that suppresses the rotation of the rotor, and serves as a brake, so that the vehicle body can be safely stopped in the middle of the slope.

Furthermore, two pressure sensors are provided to detect this pressure when a forward or backward force is applied to the handle,
When a motor control mechanism that controls the rotation of the motor by detecting the pressure difference between the two pressure sensors is installed, when the handle is pushed out, a signal larger than the pressure sensor on the reverse side is transmitted to the differential amplifier from the pressure sensor on the forward side. A drive signal corresponding to the input difference is output to the motor.

In the case of stopping on the way, when the handle is pulled, a force is applied to the reverse pressure sensor, and a signal larger than the forward pressure sensor is input to the differential amplifier, so the drive signal is not output and the motor stops.

In addition, a motor stop mechanism that stops the motor when both pressure sensors detect a pressure higher than the specified pressure at the same time. In order to perform a gripping action,
At this time, if a large pressure above a certain level is detected at the same time, the drive signal is not output and the motor can be stopped suddenly.

(Embodiment) Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings.

1 to 4 show an embodiment of the present invention, in which 1 is a frame formed of a pipe, and a handle 2 also formed of a pipe is connected to an upper portion of the frame 1. There is.

A luggage case 3 is attached to the front surface of the frame 1, and a box 4 is connected to the lower side of the frame 1.

A wheel drive shaft 5 is horizontally attached by penetrating the inside of the box 4, and wheels 6 and 6 are respectively attached to both ends of the shaft projecting outward.
Is installed.

A DC motor 7 is provided in the box 4, and the DC motor 7 is connected to a battery 8.

A small-diameter gear 10A is attached to the output shaft 9 of the DC motor 7 as shown in FIG.
It meshes with the reduction gear 10B attached to.

Further, between the reduction gear 10B and the wheel drive shaft 5, the rotational torque of the wheel drive shaft 5 is transmitted to the DC motor 7 only when a force in the reverse direction is applied to the handle 2, and the force in the forward direction is applied. There is a one-way clutch 11 that does not transmit when the vehicle is on.

A handle 12 is provided on the upper portion of the handle 2, and the handle 12
A pressure sensor 13 is attached to the rear side of 12.

FIG. 4 shows a motor control mechanism in which a DC motor 7 is connected to a battery 8 via a transistor Q1.
The pressure sensor 13 is connected to the base of the transistor Q1 via a pulse width modifier 15.

Next, the operation of the electric wheelbarrow having the above structure will be described. When the handle 12 of the handle 2 is grasped and lightly pushed on a flat road to move forward, the wheel drive shaft 5 and the reduction gear 10B intervene. Since the directional clutch 11 works in the slipping direction, the torque of the wheels 6 is not transmitted to the reduction gear 10B side, and even when the DC motor 7 is not driven, the vehicle can be lightly moved forward.

In this case, the one-way clutch 11
If the wheel drive shaft 5 and the DC motor 7 are connected to each other by the gear 10A and the reduction gear 10B, and the DC motor 7 is not energized and the vehicle body is pushed, the permanent magnet for the field magnet inside the motor is changed. It works to suppress rotation. Since this suppression torque is amplified by the reduction ratio and transmitted to the steering wheel 2,
Even if you try to move forward on a flat road in the sky, a considerable amount of force is required.

Therefore, in the conventional electric carrier, the DC motor 7 must be constantly driven even on a flat road, and the battery 8 is consumed unnecessarily. However, in the electric handcart of the present invention, the one-way clutch 11 is used. Since it is disconnected from the DC motor 7, the braking torque is not transmitted and the vehicle can be moved forward manually.

Further, in the electric wheelbarrow of the present invention, when the handle 12 of the handle 2 is grasped by hand and pushed forward, the pressure sensor 13 detects this pushing force, and an output proportional to this pressure is output by the pulse width modulator 15
Entered in. The pulse width varying device 15 outputs a pulse whose duty changes in proportion to the input, and when this pulse is output to the transistor Q1, the DC motor 7 is energized and rotates.

When the DC motor 7 rotates, this drive torque is transmitted to the reduction gear 10B via the gear 10A attached to the output shaft 9, and the one-way clutch 11 is brought into the connected state.
Is transmitted to the vehicle body, and combined with the pushing force of the steering wheel 2, the vehicle body can be moved forward.

Therefore, when the road is flat or the load is light, the pressure applied to the pressure sensor 13 provided on the handle 12 is small, and in proportion to this, the amount of electricity to the DC motor 7 is small and the vehicle can be advanced almost by manpower.

When the load is heavy or when you are pushing uphill, the force pushing the handle 12 becomes strong, and the pressure sensor 13 receives a large pressure, so that the amount of electricity to the DC motor 7 increases and a large driving torque is generated. The vehicle body can be pushed forward with a constant force.

When you stop while walking, inertia causes the car body to move slightly forward,
Since the pressure applied to the pressure sensor 13 becomes zero, the driving of the DC motor 7 is stopped and the vehicle body is stopped.

When the vehicle stops due to tiredness in the middle of the ascending slope, the wheel drive shaft 5 tries to rotate backward due to the force of the vehicle body trying to lower due to its own weight.

In this case, between the wheel drive shaft 5 and the reduction gear 10B, the one-way clutch 11 that transmits the rotational torque of the wheel drive shaft 5 only when the rearward direction force is applied to the handle 2 is provided. Directly connected to the DC motor 7.

Therefore, the field permanent magnet inside the motor that is not in the energized state acts as a brake due to the suppression torque that suppresses the rotation of the rotor, and the vehicle body can be safely stopped in the middle of the slope.

Therefore, by simply grasping the handle 12 and pushing the handle 2 forward without requiring a complicated switch operation, the pushing force at this time is automatically detected, and the DC motor 7 is driven by a driving torque proportional to the pushing force. Since it is driven, power is efficiently consumed, and a small battery 8 having a small capacity is sufficient.

For example, in ordinary shopping, the DC motor 7 is at most 200m driven uphill from within 2-3km from the house to the store.
The time is about 5 minutes. Therefore, the battery 8 to be used is small, about 100 to 200 g, and the total weight of the drive mechanism is 300 to 400 g, including the DC motor 7, the speed reduction mechanism, the one-way clutch 11, etc., and is very lightweight. It is also convenient to carry.

5 and 6 show another embodiment of the present invention, in which pressure sensors 13A and 13B are provided on the front side and the rear side of the handle 12, respectively.

In this control mechanism, as shown in FIG. 6, two pressure sensors 13A and 13B are connected to a pulse width varying device 15 via a differential amplifier 16.

Further, the pressure sensors 13A and 13B are also connected to the two-input voltage detecting element 17, and when the pressure signals above a certain level are simultaneously input here, the pressure sensors 13A and 13B are output to the transistor Q2.
The transistor Q2 is connected in parallel with the transistor Q1 and the other structure is the same as that of the embodiment shown in FIG.

In the electric wheelbarrow with this configuration, when the handle 12 of the handle 2 is gripped with a hand, a signal proportional to the pressure applied from the front and rear pressure sensors 13A and 13B is output to the differential amplifier 16, but if the gripping force is equal, The pulse width modifier is canceled by the differential amplifier 16.
No signal is output to 15, and the DC motor 7 is not driven.

When the handle 2 is pushed out, a signal larger than the pressure sensor 13B from the pressure sensor 13A is input to the differential amplifier 16, where a signal corresponding to the input difference is output to the pulse width variable device 15 to drive the DC motor 7. .

If the handle 12 is pulled halfway, a force is applied to the front pressure sensor 13B and a signal larger than the rear pressure sensor 13A is input to the differential amplifier 16, so no motor drive pulse is output and the DC motor 7 stops.

Also, when some dangerous state occurs and it is urgently attempted to stop it, it operates to firmly grasp the handle 12 and stop it, but at this time, the two-input voltage detection element 17 simultaneously detects a large pressure above a certain level. Then, the signal is output to the transistor Q2.

As a result, the transistor Q2 becomes conductive, and since no pulse signal is input to the transistor Q1, the transistor Q2 becomes non-conductive and the DC motor 7 can be stopped suddenly.

When the vehicle is stopped on the way uphill, the wheel drive shaft 5 is directly connected to the DC motor 7 through the one-way clutch 11 as in the above-described embodiment, and the restraint torque acts to act as a brake and the vehicle body moves on a slope. You can safely stop on the way.

In the above-described embodiment, the electric handcart that pushes the handle 2 to move the vehicle forward is described, but the vehicle 2 may move forward while pulling the handle 2. In this case, contrary to FIG. 5, the pressure sensor 13B may be attached to the front side of the handle 12 and the pressure sensor 13A may be attached to the rear side.

The one-way clutch 11 may have a structure interposed between the output shaft 9 of the DC motor 7 and the reduction gear 10B, and the reduction mechanism may be a combination of a plurality of reduction gears.

The pressure sensor is not limited to the one attached to the handle, but may be attached in the middle of the handle, or the handle may be rotatably joined to the frame and the pressure sensor may be attached to this joint.

In the above embodiment, the case where the battery 8 is used as the power source has been described. However, since the power consumption is small, a dry cell may be used.

[Effects of the Invention] As described above, according to the present invention, it is possible to automatically detect the pushing force at this time by simply grasping the handle and pushing the handle forward without requiring a complicated switch operation, and in proportion to this. Since the motor is driven by the specified drive torque, it is easy to operate, and it stops securely even when stopped on a slope and is excellent in safety, and the frequency of use of the battery is minimized to reduce power consumption and improve economic efficiency. Thus, it is possible to obtain an electric wheelbarrow in which the battery is downsized and the weight is reduced.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
The figure shows the front view of the electric wheelbarrow with the main part broken away.
FIG. 4 is a side view of FIG. 1, FIG. 3 is an explanatory view of a drive mechanism, and FIG.
FIG. 5 is a circuit diagram showing a motor control mechanism, FIGS. 5 and 6 show other embodiments, FIG. 5 is a sectional view of a handle having two pressure sensors attached, and FIG. 6 is a motor control mechanism. It is a circuit diagram shown. 1 ... Frame, 2 ... Handle, 3 ... Luggage, 4 ... Box, 5 ... Wheel drive shaft, 6 ... Wheel, 7 ... DC motor, 8 ... Battery, 9 ... Output shaft, 10A ... Gear 10B …… Reduction gear, 11 …… One-way clutch 12 …… Handle 13, 13A, 13B …… Pressure sensor 15 …… Pulse width modifier, 16 …… Differential amplifier 17 …… Two-input voltage detection element Q1, Q2 …… Transistor

Claims (3)

[Scope of utility model registration request] 1. A frame to which a luggage compartment is attached, a handle attached to this frame, a pressure sensor attached to this handle for detecting this pressure when a forward force is applied, and driven by a battery. The wheel drive shaft is provided between the motor, the output shaft of the motor and the gear mounted here, or between the reduction gear that meshes with this gear and the wheel drive shaft, and transmits the rotational force of the motor to the wheel drive shaft. An electric handcart comprising: a one-way clutch for transmitting a reverse direction rotational torque to a motor; and a motor control mechanism for controlling the rotation of the motor by a detection signal of the pressure sensor. 2. A motor for controlling rotation of a motor by providing two pressure sensors for respectively detecting the pressure when a forward and backward force is applied to the handle, and detecting a pressure difference between the two pressure sensors. The electric wheelbarrow according to claim 1, further comprising a control mechanism. 3. The electric wheelbarrow according to claim 2, further comprising a motor stop mechanism for stopping the motor when the two pressure sensors simultaneously detect a pressure higher than a predetermined value.