JP3062721B2 - Front and rear wheel drive vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front and rear wheel drive vehicle in which one of front and rear wheels is driven by an engine and the other is driven by an electric motor.

[0002]

2. Description of the Related Art Conventionally, in this type of front-rear wheel drive vehicle, there is known a vehicle which uses an AC motor as an electric motor and which can operate the electric motor over the entire vehicle speed range by inverter control (Japanese Patent Laid-Open No. HEI 9-163556). 3-159502).

[0003]

In order to cover the entire vehicle speed range as in the above conventional example, it is necessary to use an electric motor having a large output, and furthermore, an inverter circuit is required and the cost is increased. . By the way, in order to limit the purpose of use of the electric motor to starting assistance on slippery roads such as snowy roads,
If the electric motor is operated only when the vehicle speed is equal to or lower than the set value, an inexpensive D used as a starter motor or the like can be obtained.
A C brush motor can be used. However, in this case, the electric motor is always operated during the slow operation due to traffic congestion or the like, and the durability of the brush becomes a problem.
In view of the above, the present invention provides a front-rear wheel drive vehicle that operates an electric motor at the time of starting to assist starting, and that can temporarily operate the electric motor to ensure the durability of the motor. Its purpose is to provide.

[0004]

In order to achieve the above object,
According to the onset bright, in a vehicle that drives the other by an electric motor to drive one of the front and rear wheels in an engine, comprising a means for confirming the starting operation of the vehicle, actuates only when starting operation of the electric motor, the electric Means for detecting the load of the motor is provided, and when the motor load increases once and then decreases, the operation of the electric motor is stopped.

[0005]

The start operation of the vehicle can be confirmed by, for example, the operation of turning off the brake, the operation of turning on the clutch (switching to the D range or the R range in an automatic vehicle), and the operation of depressing the accelerator pedal. For this purpose, a condition that the vehicle speed is equal to or lower than a predetermined value may be added as a condition for confirming the start operation. However, this alone determines that the start operation is being performed even during slow running, and the electric motor operates.
Here, the load of the electric motor rapidly increases at the beginning of the operation of the electric motor, and decreases when the vehicle starts to move due to the rotation of wheels driven by the electric motor. Therefore, according to this onset bright, the electric motor operation is to be stopped when the vehicle begins to move in the starting operation. In addition, even if the wheels driven by the engine are slipping on the road surface, if the vehicle starts moving, the wheels grip the road surface, so that the vehicle can start reliably.

[0006]

1 is a four-wheeled vehicle having a pair of front wheels 1 and a pair of rear wheels 2 and a pair of left and right front wheels 1 with an engine 3.
And a pair of left and right rear wheels 2 are driven by an electric motor 5 via a speed reducer 6, a clutch 7 and a differential gear 8.

The electric motor 5 is constituted by a DC brush motor, and the motor 5 is connected to a vehicle-mounted battery 9 via a forward / reverse switching circuit 10. And forward / reverse switching circuit 1
A normally open relay switch 12a that is turned on and off by a relay 12 provided in the control circuit 11 is provided in a connection circuit between the battery 0 and the battery 9 so that when the relay 12 is energized, the relay switch 12a is turned on and the motor is electrically operated. The motor 5 is operated, the clutch 7 is engaged, and the rear wheel 2 is driven. The clutch 7 is disengaged when the relay switch 12a is turned off.
0 is switched and controlled in conjunction with the operation of the shift lever in the passenger compartment.

[0008] The control circuit 11, confirmation of the calling Susumu operation means 1
4, a normally open switch 14b which is turned on via a relay 14a at the time of starting operation, and a slip ratio measuring means 16
Relay when the slip ratio of the front wheel 1 is greater than or equal to a predetermined value
A normally open switch 16b that is turned on via 16a;
The motor load is temporarily increased by the motor load detecting means 17
And then turned off via relay 17a
And a normally-closed switch 17b is interposed in series,
When these switches 14b, 16b, 17b are all on, the relay 12 is energized.

The start confirming means 14 includes a signal for a brake switch which is turned on when the brake pedal is depressed, a signal for an accelerator switch which is turned on when the accelerator pedal is depressed, and a switch for detecting whether or not the transmission 4 is in a neutral state. For example, when the transmission 4 is an automatic transmission, a position signal of a shift lever is received, and when the transmission 4 is a manual transmission, a signal of a switch including a clutch switch linked to a clutch pedal and a signal of a vehicle speed sensor are received.
When the brake switch is off, the accelerator switch is on, the transmission 4 is in the non-neutral state, and the vehicle speed satisfies the four conditions below the set value, it is determined that the vehicle is starting, and the relay 14a is energized to turn on the switch 14b. It is configured to. In a vehicle equipped with a torque sensor that detects the torque on the output side of the transmission 4, the start operation can be confirmed by the brake switch, the torque sensor, and the vehicle speed sensor. In addition, the slip ratio measuring means 16 is provided for each wheel 1, 2
Based on the signal of the wheel speed sensor that detects the rotation speed of the vehicle
The rotational speed difference between the rear wheels 1 and 2 is detected and the front wheel 1
It is configured to measure the slip rate of the vehicle.

[0010] According to the above configuration, outgoing advance operation at the front wheels 1
, The electric motor 5 is operated to drive the rear wheel 2. In this case, since the rear wheel 2 can be driven at a required low speed that does not cause slippage by setting the rotation speed of the electric motor 5 and the gear ratio of the speed reducer 6, the front wheel 1 can be driven due to an incorrect accelerator operation on a snowy road or the like. Even if the vehicle slips, the vehicle can be reliably moved. Front wheel 1 if the vehicle starts moving
Makes it easier to grip the road surface, so that the vehicle can start running only with the front wheels 1 thereafter. Here, the load of the electric motor 5 is
When it suddenly increases at the beginning of operation and the vehicle starts to move by driving the rear wheels 2,
Decrease. Therefore, when the vehicle starts moving, the load detection
The step 17 turns off the switch 17b via the relay 17a.
As a result, the operation of the electric motor 5 is stopped, and the malfunction of the brush of the electric motor 5 due to the continuous operation of the electric motor 5 during the slow operation does not occur.

[0011]

When the motor load is large, the motor current is large and the motor voltage is small.
The motor current when starting to change as shown in FIG. 2 (a), the motor voltage changes as shown in FIG. 2 (b). Thus, the load detecting means 17 can be configured to detect the motor load using the motor current or the motor voltage as a parameter. In this case, when the motor current once increases after startup and then decreases to a predetermined value. Alternatively, the operation of the electric motor 5 may be stopped when the motor voltage increases to a predetermined value after the start. Note that it is also possible to detect the motor load using the heat generated by the motor as a parameter.

In the above embodiment, the front wheels 1 are driven by the engine 3, but the rear wheels 2 are driven by the engine 3,
The present invention can be similarly applied to a vehicle in which the front wheel 1 is driven by the electric motor 5.

[0014]

As is apparent from the above description, according to the present invention, since the electric motor can be used only for starting assistance, the electric motor can be a small and inexpensive DC brush motor, and the cost can be reduced. In addition, since the electric motor is only operated temporarily at the time of starting, D
Even if a C brush motor is used, durability can be ensured.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of an embodiment of the present invention.

2A is a graph showing a change in motor current, and FIG.
Graph showing the change in data voltage

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 3 Engine 5 Electric motor 11 Control circuit 14 Start check means 17 Load detection means

──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Koji Ono 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Inventor Jun Aoki 1-4-1 Chuo, Wako-shi, Saitama Pref. (56) References JP-A-5-131858 (JP, A) JP-A-5-319127 (JP, A) JP-A-6-217456 (JP, A) JP-A-56-21916 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 17/356 B60K 6/02 B60L 11/00-11/14

Claims (1)

(57) [Claims] 1. A vehicle in which one of front and rear wheels is driven by an engine and the other is driven by an electric motor, the vehicle includes means for confirming a start operation of the vehicle. A front-rear wheel drive vehicle provided with means for detecting a load, wherein the operation of the electric motor is stopped when the motor load once increases and then decreases.