JPS6338031A - Auxiliary driving device for automobile - Google Patents

Abstract

PURPOSE:To improve driving capacity by using a DC motor and driving said motor with a power from a DC generator which is increased with increase in vehicle speed, in the captioned device in which a driven wheel is driven by bringing a roller driven by said motor into pressure contact with it. CONSTITUTION:When the captioned device is applied to a front wheel driven vehicle, rollers 4 which can be brought into contact with right and left rear wheels 3 respectively are provided and rotated by DC motors 6. The rollers 4 are rotatably supported by the bottom part of a swinging arms which are swung by motors 20 and, by controlling the swing of the swinging arms, the rollers 4 can be brought into contact with, and separated from, the rear wheels 3. Power is fed to the motors 6, 20 from an alternator 35 which is driven by an engine 30 via an electromagnetic clutch 34. Also, in this case, the power generated by the alternator 35 is controlled by a control unit 36 in such a way that a generated voltage is increased with increase in vehicle speed, in a zone where a vehicle speed signal SP is above a defined vehicle speed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an auxiliary drive device for an automobile, and an auxiliary drive in which a driven wheel of an automobile is driven by a roller that is pressed against the driven wheel and driven by a motor. Regarding equipment.

(Prior Art) In general, automobiles employ a front-wheel or rear-wheel drive system that transmits engine output only to the front or rear wheels.This type of drive system has a simpler structure than a four-wheel drive system. It has the advantage of being lightweight and being manufactured at low cost. However, compared to four-wheel drive vehicles, front-wheel or rear-wheel drive vehicles have the disadvantage that it is difficult to escape from snowy roads or muddy areas where the wheels tend to slip.

Japanese Utility Model Application Publication No. 58-112636 discloses a simple auxiliary drive device for converting a front-wheel drive vehicle into a simple four-wheel drive system. This auxiliary drive device includes a roller, a pressing mechanism for pressing the roller against the peripheral surface of the driven wheel, and a motor for rotationally driving the roller. According to this auxiliary drive device, the driving wheels can be driven by the engine and the driven wheels can be driven by the motor at the same time, so that emergency escape from snowy roads, muddy areas, etc. can be performed.

By the way, the applicant of this application has filed an earlier application (Japanese Patent Application No. 60-165).
No. 075), an auxiliary drive for an automobile includes an alternating current generator driven by an engine and an alternating current motor supplied with power from the alternating current generator, and the alternating current motor drives a roller pressed by a driven wheel. proposed a device.

In the above AC type auxiliary drive device, it is operated in the first gear position or the reverse gear position,
In this case, since there is a proportional relationship between the vehicle speed, the frequency of the alternator output, and the rotational speed of the alternating current motor, we focused on the fact that the output torque of the alternating current motor can be held approximately constant even if the vehicle speed fluctuates. Output torque control is simplified.

(Problems to be Solved by the Invention) In the case of the AC-type auxiliary drive device related to the above-mentioned Hikari application, the auxiliary drive The device becomes larger and heavier. It is desirable that the drive mechanism main body portion of the auxiliary drive device can be easily attached to and detached from the vehicle body by a single driver of the vehicle, and it is necessary to be small and lightweight.

Furthermore, in the AC system, due to the characteristics of the AC motor, in order to obtain effective torque, it is necessary to set the vehicle speed and the output frequency of the AC generator in a proportional relationship with a proportionality constant within a predetermined range. Furthermore, even if the vehicle speed and the output frequency of the alternator are set in a predetermined proportional relationship, if the gear ratio changes due to shifting, this predetermined proportional relationship will break down, so it is necessary to fix the shift range to a predetermined range. It is not possible to obtain the desired torque.

Therefore, instead of the AC-type auxiliary drive device that depends on the output frequency of the alternator, we installed an alternator that is driven by the engine so that it does not depend on the output frequency of the generator. It is conceivable to use a direct current type auxiliary drive device to drive the rollers.

However, in the auxiliary drive system, the rotational speed of the rollers, that is, the rotational speed of the motor, must be increased as the vehicle speed increases, but the relationship between the rotational speed, current, and output torque of the DC motor is as shown in Figure 11. Therefore, when the rotational speed increases, the current decreases and the output torque decreases, and when the rotational speed decreases, the current increases and the output torque increases, so the output torque is kept constant and driven economically. It's difficult. In particular, when starting on a snowy road, the rotational speed of the motor is low, so the output torque becomes excessive as described above, causing the driven wheels driven by rollers to slip, causing the problem that they no longer function as an auxiliary drive device.

As a countermeasure, it may be possible to appropriately control the current supplied to the motor using a chopper circuit or the like, but this would make the control device complicated and expensive.

(Means for Solving the Problems) The auxiliary drive device for a motor vehicle according to the present invention has only one of the front and rear wheels as a driving wheel driven by an engine, and the other driven wheel is pressed against the driven wheel. In an auxiliary drive device for an automobile, which is driven by a roller driven by a motor, the motor is constituted by a DC motor, and the generator for feeding power to the DC motor is constituted by a DC generator driven by the engine, A vehicle speed detection means for detecting the running speed of the vehicle is provided, and a generated voltage control means is provided for controlling the generated voltage to increase in accordance with an increase in vehicle speed in a region exceeding a predetermined vehicle speed based on the output from the vehicle speed detection means. It was established.

(Function) In the automobile auxiliary drive device according to the present invention, as described above, a DC generator and a DC motor for driving the rollers are provided,
The DC generator is configured to supply power to the DC motor to drive the rollers, and the vehicle speed detection means detects the vehicle speed, and based on the output, the power generation voltage control means controls the power generation voltage in an area exceeding a predetermined vehicle speed. It is controlled to increase as the vehicle speed increases. Therefore, in a region above a predetermined vehicle speed, the voltage supplied to the motor increases as the vehicle speed increases, and the rollers are driven with substantially constant torque even if the vehicle speed fluctuates.

(Effects of the Invention) According to the auxiliary drive device for a vehicle according to the present invention, as described above, in the region above a predetermined vehicle speed, the generated voltage increases as the vehicle speed increases, and the output torque of the motor remains approximately constant. .

By controlling the generated voltage in this way, there is no slippage due to excessive output torque when the vehicle starts, and the output torque does not become too small when the vehicle speed increases.

(Example) Hereinafter, an example of an auxiliary drive device for an automobile according to the present invention will be described based on the drawings.

The automobile 1 in this embodiment is a front-wheel drive vehicle, and as shown in FIG. The rollers 4 are detachably attached to the vehicle body, and the rollers 4 come into contact with the corresponding rear wheels 3.

Here, since the drive mechanism body part 2 that drives the left rear wheel 3 and the drive mechanism body part 2 that drives the right rear wheel 3 have symmetrical structures, the drive mechanism body part 2 that drives the left rear wheel 3 has a symmetrical structure. I will explain about the things.

First, a main frame 5 consisting of an upper plate 5a, a rear plate 5b, and an outer plate 5C is provided, and a motor 6 is disposed below this main frame 5 facing in the vehicle width direction. It is fixed to the outer plate 5C by four ports 7, and the motor 6 is attached to the inner end side of the main frame 5.
The motor 6 is attached to the main frame 5 by screwing the bolt 9 at the upper end of the turned band 8 to the main frame 5.

Below the motor 6, a metal roller 4 is disposed facing in the vehicle width direction and comes into contact with the rearmost part of the outer peripheral surface of the rear wheel 3. It is rotatably attached to the section via a bearing.

That is, the upper end of the outer drive arm IO is rotatably attached to the output shaft 6b of the motor 6, which is pushed through the circular opening of the outer plate 5C of the main frame 5, via a bearing 12. An outer end portion of a roller shaft 4a is rotatably supported via a bearing at the lower end of the motor 6, and an upper end portion of an inner drive arm 11 is supported via a bearing from a motor shaft 6c protruding toward the inner end of the motor 6. The inner end of the roller shaft 4a is rotatably supported at the lower end of the inner drive arm 11 via a bearing. In this way, the roller 4 is rotatably supported by a pair of inner and outer drive arms 10 and 11, and by driving the auxiliary arm 10 and II at the pivot joint at the upper end, the roller 4 is moved in a substantially horizontal direction. It can be moved back and forth.

In order to transmit the rotational driving force of the motor 6 to the roller shaft 4a to drive the roller 4 in forward and reverse rotation, the output shaft 6b of the motor 6 is
A small diameter sprocket 13 is fixed to the outer end of the rotor shaft 4a, and a large diameter sprocket 14 is fixed to the outer end of the rotor shaft 4a.
5 is hung, and this chain 15 and both sprockets 1
A cover 16 that covers the outside of the parts 3 and 14 is detachably attached to the outer plate 5C with thumb screws 17.

Furthermore, a pressing mechanism for pressing the roller 4 with a predetermined pressing force against the rear wheel 3 that moves up and down relative to the vehicle body is configured as follows.

An upper plate 18 is provided on the rear inner side of the main frame 5.
A sub-frame 18 is provided, which includes a front plate 18b, a front plate 18b, and an outer plate 18C. A gear mechanism covered by a case 19 is attached to the case 19, and a pressing drive motor 20 is installed horizontally in the front-rear direction at the rear of the case 19. Consisting of a worm gear fixed to a shaft and a driven gear that meshes with the worm gear, the gear shaft 21 fixed to the driven gear protrudes to the outside of the outer plate 18c of the subframe 18. The upper end of the swing plate 22 is fixed.

On the other hand, arm parts are integrally extended rearward from the respective lower ends of the outer drive arm 10 and the inner I$ drive arm 11, and the inner and outer arm parts are connected by a connecting plate 23, and are connected to the width center part of the rear wheel 30. The center part of the connecting plate 23 and the rocking plate 2 at corresponding positions
A pressing shaft 24 extending from the lower end of the rocking plate 22 is provided, and the pressing shaft 24 is slidably fitted onto a piston rod 24a rotatably connected to the lower end of the rocking plate 22 and the piston rod 24a. A cylinder 24b, a compression coil spring 24c incorporated in the cylinder 24b, and a connecting plate 23 are connected to the front end side portion of the cylinder 24b via a ball joint.
The rod 24d is screwed onto the rod 24d.

In this way, by swinging the swinging plate 22 by the pressing drive motor 20 via the worm gear and the driven gear, the pair of 1&swing arms 1O and 11 (outside and outside) are swung forward through the pushing shaft 24. The roller 4 can be moved to press the rear wheel 3, or the swing arms 10 and 11 can be moved backward to separate the roller 4 from the rear wheel 3. However, when the pressing force exceeds a set value, the compression coil spring 24c contracts. Incidentally, the reference numeral 48 is an inverter that detects the backward swinging of the swinging plate 22.

In order to detachably attach the drive mechanism body 2 to the vehicle body immediately behind the rear wheel 3, an upper plate 5a of the main frame 5 is provided.
As shown in FIG. 2, a stepped mounting portion 25 matching the stepped mounting portion formed by the top plate 18a of the sub-frame 18 is provided in the rear portion of the vehicle body of the wheel house 26. The drive mechanism main body 2 weighing approximately 20 kg is placed from the side on the lower surface of the step-like mounting portion 25, and the guide piece 25a is engaged with the locking hole 27 of the main frame 5, and the guide piece 25b With the oblique side of the upper plate 18a of the frame 18 locked, screw each bolt into the corresponding nut hole 29 of the upper plate 5a, 18a from the four bolt holes 28 of the stepped mounting part 25 from inside the trunk. By doing so, the drive mechanism main body section 2 is removably fixed to the vehicle body.

Next, the overall configuration of the auxiliary drive device will be explained based on FIGS. 6 to 10.

As shown in FIG. 6, a pair of left and right front wheels 3A are driven by an engine 30 via a transmission 31.
An alternator 35 is connected to the output shaft of the engine 30 via a pulley 32, a belt 33, and an electromagnetic clutch 34.
The electromagnetic clutch 34 is controlled by a control unit 36.

Power is supplied from the alternator 35 to the motor 6 of the auxiliary drive mechanism body 2 via a relay box 37, and power is supplied to the press drive motor 20 from the control unit 36. Above control unit 3
6 outputs an excitation current I for controlling the generated voltage to the rotor coil of the alternator 35, and a switching control signal F·R is output from the control unit 36 to the Revonox 37.

On the other hand, for example, a pink-up coil type vehicle speed sensor 3 is connected to the output shaft of the transmission 31 and the front wheel drive shaft.
8 is provided, and its vehicle speed signal SP is output to the control unit 36, as well as a drive command signal S0 that instructs the drive of the auxiliary drive device, a clutch signal S that is output when the clutch is connected, and is output when the first gear is selected. The first to be
An operating state signal S including a high gear signal S full, a reverse gear signal S output when a reverse gear is selected, and the like is output to the control unit 36.

Here, the operation of the auxiliary drive device will be explained.

When the start switch that starts the auxiliary drive device is turned ON, the drive command signal S0 is sent to the control unit 1-3.
6, the connection drive current C is output from the control unit 36 to the electromagnetic clutch 34, and the electromagnetic clutch 3
4 is connected, and in parallel, a vehicle speed signal SP from the vehicle speed sensor 38 is output to the control unit 36, and an excitation current l of a voltage according to the vehicle speed is transmitted from the control unit 36 to the rotor coil of the alternator 35 as described later. is output, and the alternator 35 starts generating electricity.

On the other hand, when the first gear signal S2 or the reverse gear signal S3 is input to the control unit 36, the corresponding switching signal F or R is output from the control unit 36 to the relay box 37, and the relay box 37 sends the switching signal F Or, the connection state is changed according to R, and current from the alternator 35 is supplied to the left and right pair of motors 6, and the motors 6 are rotationally driven in the forward rotation (forward) side or the reverse rotation (backward) side, and each roller 4 is driven by a motor 6.

Next, when the clutch signal Sl is output to the control unit 36, a drive current is output from the control unit 36 to the left and right pair of press drive motors 20 for a predetermined period of time, and each roller 4 is moved by each press mechanism. The peripheral surface of the rear wheels 3 is pressed and biased, and each rear wheel 3 is auxiliary rotationally driven by each roller 4, resulting in a four-wheel drive state.

By the way, when driving with the auxiliary drive device activated as described above, the rotational speed of the rollers 4, that is, the rotational speed of the motor 6, needs to increase as the vehicle speed increases. In order to keep the torque of the motor 6 substantially constant even when the vehicle speed varies, it is necessary to increase the voltage generated by the alternator 35 as the vehicle speed increases.

That is, when the general characteristics of the DC motor (FIG. 1I) are converted into the relationship between rotational speed and output torque, the characteristics shown in FIG. 10 are obtained. As can be seen from FIG. 10, in order to keep the output torque approximately constant even if the rotational speed of the DC motor changes, it is necessary to increase the supply voltage in accordance with the increase in rotational speed (linear).

reference).

When the automobile starts on a snowy road or the like, it is necessary to increase the voltage supplied to the DC motor (see straight line L2) in order to obtain an output torque larger than that during normal driving.

Therefore, in the auxiliary drive device of the present application, the generated voltage is controlled as shown in FIG. 8 based on the vehicle speed signal SP, and the output torque of the motor 6 is controlled as shown in FIG. 9.

That is, in the control unit 36, a generated voltage control section 39 that controls the generated voltage by controlling the voltage of the excitation current I to the rotor coil of the alternator 35 based on the vehicle speed signal SP is configured as shown in FIG. ing.

That is, the power generation voltage control section 39 changes the vehicle speed signal SP to F/
An F/V converter 40 that converts V (frequency/voltage), a bias vl and a first operational amplifier 41 for increasing the generated voltage from the start until the set vehicle speed reaches the set vehicle speed, as shown in FIG. As shown by α・■2 in Figure 8, bias ■z is used to increase the generated voltage by a predetermined value regardless of vehicle speed.
, an adder 43, an amplifier 44, a coefficient unit 47 and a second operational amplifier 46 for performing feedback control so that the generated voltage does not deviate from a target value.

The output terminal of the F/V converter 40 is connected to the first adder 43 and the negative input terminal of the first operational amplifier 41, the bias v1 is connected to the positive input terminal of the first operational amplifier 41, and the output terminal of the first operational amplifier 41 is connected to the negative input terminal of the first operational amplifier 41. The terminal is diode 4
Bias (2) is connected to the adder 43 via the bias (2). The output terminal of the adder 43 is connected to the positive input terminal of the second operational amplifier 46,
The output line of the alternator 35 is connected to the negative input terminal of the second operational amplifier 46 via a coefficient multiplier 47, the output terminal of the second operational amplifier 46 is connected to the amplifier 44, and the output terminal of the amplifier 44 is connected to the rotor coil 35 of the alternator 35.
connected to a.

In the configuration of the power generation voltage control section 39, the output from the F/■ converter 40 is sent to the rotor coil 35 via the amplifier 44.
If only input is made to a, the generated voltage will be proportional to the vehicle speed as shown by straight line A in Fig. 8, but since bias 2 uniformly increases the voltage level of the signal input to the amplifier 44, the actual generated voltage will be The voltage is higher than that of straight line A by α·■2 (where α is a constant), as shown by straight line B in FIG.

Then, set vehicle speed v1 set by vehicle speed or bias ■1
In the following cases, the output voltage of the first operational amplifier 41 increases as the vehicle speed becomes smaller than the set vehicle speed v1, so that the voltage becomes vIc in FIG.

Furthermore, when the load on the roller drive motor 6 increases and the motor current increases, the voltage on the output line decreases due to the internal impedance system of the alternator 35, and the output of the second operational amplifier 46 is divided between the input signal to its positive input terminal and the negative input terminal. Since the voltage increases according to the voltage difference between the input signal and the input signal, feed hack control is performed so that the generated voltage does not vary greatly from straight lines B and C in FIG.

When the relationship between the generated voltage and the vehicle speed represented by the straight lines B and C in FIG. 8 is rewritten as the relationship between the motor output torque and the vehicle speed, the relationship is as shown in FIG. 9.

That is, when the vehicle is started, it can be started with a large starting torque, and when the vehicle speed reaches a set vehicle speed of 11 or higher, the vehicle can run economically with a substantially constant output torque that is greater than the running resistance.

Incidentally, in the above embodiment, the alternator 35 is used as a DC generator.
However, a dynamo may be used as the DC generator and the input voltage and current to the field coil may be controlled as described above.

[Brief explanation of drawings]

Figures 1 to 9 of the drawings show embodiments of the present invention, with Figure 1 being a side view of the main parts of an automobile with the drive mechanism main body of the auxiliary drive device attached, and Figure 2 showing the step-like installation. perspective view of the section;
Figure 3 is a plan view of the main body of the drive mechanism, Figure 4 is a side view of the same,
Figure 5 is a front view of the same, Figure 6 is an overall configuration diagram of the auxiliary drive device,
Figure 7 is a configuration diagram of the power generation voltage control section of the control unit, Figure 8 is a diagram of power generation voltage, Figure 9 is a diagram of motor output torque, and Figures 1O and 11 are general diagrams of DC motors. It is a line diagram showing characteristics. 2. Drive mechanism body, 3. Rear wheel, 6. Motor, 34. Electromagnetic clutch, 35. Alternator.
36...Control unit, 37...Relay box, 38...Vehicle speed sensor, 39...Generation voltage control section.

Claims (1)

[Claims] (1) In an auxiliary drive system for an automobile in which only one of the front and rear wheels is a driving wheel driven by an engine, and the other driven wheel is driven by a roller pressed against the driven wheel and driven by a motor. , the motor is composed of a DC motor, and the generator that supplies power to the DC motor is composed of a DC generator driven by the engine, and includes a vehicle speed detecting means for detecting the traveling speed of the automobile, and an output signal from the vehicle speed detecting means. 1. An auxiliary drive device for a motor vehicle, comprising a power generation voltage control means for controlling the power generation voltage to increase in accordance with an increase in vehicle speed in a region of a predetermined vehicle speed or higher based on the output.