JPS6291636A - Driving force control device for vehicle - Google Patents

Abstract

PURPOSE:To secure not only the running stability of a vehicle for a large slip but also the improvement of ride feeling for a small slip by accelerating or decelerating the closing speed of a throttle valve depending on the magnitude of a slip ratio. CONSTITUTION:The revolving speed of a driving wheel is detected by a driving wheel revolving speed detecting means 1, simultaneously, the revolving speed of a hot-driven wheel is also detected by a not-driven wheel revolving speed detecting means 2. And a slip ratio between a tire and a road surface is operated by a slip ratio operating means 3 based on the detected revolving speed of both the driving and not-driven wheels, then a judgement is made by a slip ratio judging means 4 as to whether the slip ratio is greater than a set value or not. With this, if the slip ratio is found to exceed the set value, the closing speed of the throttle valve is controlled continuously by a throttle valve controlling means 5 based on the slip ratio so as to decrease a driving force. Accordingly, both of the ride feeling and running stability of a vehicle can be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a vehicle driving force control device.

[Conventional technology]

As a conventional vehicle driving force control device, for example, JP-A-6
There is one described in Japanese Patent No. 0-43133.

It is used in an automobile engine output control device that controls engine output by changing the amount of fuel supplied to the engine according to the position of the accelerator pedal. Calculating means for calculating the slip rate between the tires and the road surface from the output of the means; comparison means for comparing the calculated slip rate with a set slip rate; and when the calculated slip rate is large, priority is given to the control output based on the accelerator pedal position. The system is characterized by comprising a slip rate control means that outputs a signal to forcibly reduce the fuel supply to the engine, and calculates the slip rate between the tire and the road surface from the rotational speed of the driving wheels and the non-driving wheels. By controlling the engine so that the slip rate is below a certain value, starting performance and running stability on road surfaces with a low coefficient of friction are improved.

[Problem that the invention seeks to solve]

However, in such a conventional vehicle driving force control device, the closing speed of the throttle valve at the time of slipping is set so that the slip rate between the tires and the road surface is greater than a predetermined slip rate. The system was designed to switch between two stages, normal speed and high speed, depending on whether or not the speed is high.If the closing speed of the throttle valve is set early to increase the degree of reduction in driving force in the event of excessive slip, the driving force will decrease in the event of small slip. This results in a sudden decrease in vehicle speed, resulting in an excessive reduction in speed, causing vibrations in the vehicle, and impairing ride comfort. In addition, contrary to the above, if the closing speed of the throttle valve is set to match the reduction in driving force at the time of small slip, the degree of reduction in driving force will be low at the time of excessive slip, making it difficult to control the slip, resulting in poor running stability. There was a problem that it was damaged.

[Means for solving problems]

This invention was made in response to these conventional problems, and as shown in the basic configuration diagram in Figure 1, the invention detects the rotation speed of the drive wheels of a vehicle and outputs a detection signal. a driving wheel rotation speed detection means for detecting the rotation speed of the non-driving wheels; a non-driving wheel rotation speed detection means for detecting the rotation speed of the non-driving wheels and outputting a detection signal; a slip ratio calculation means for calculating the slip ratio between the tire and the road surface based on the detection signal of the slip ratio, and a slip ratio for determining whether the slip ratio is larger than a set value based on the calculation result of the slip ratio calculation means. and a throttle valve that continuously controls the closing speed of the throttle valve in accordance with the slip ratio to reduce the driving force when the slip ratio is larger than the set value based on the determination result of the slip ratio determination means. The present invention is characterized in that the above-mentioned problems are solved by configuring a vehicle driving force control device including a control means.

[Effect]

In this invention, the driving wheel rotational speed detection means detects the rotational speed of the driving wheels, and the non-driving wheel rotational speed detection means detects the rotational speed of the non-driving wheels. The slip ratio calculating means calculates the slip ratio between the tire and the road surface based on the rotational speed of When the slip ratio is greater than the set value, the throttle valve control means continuously controls the closing speed of the throttle valve according to the slip ratio to reduce the driving force, thereby changing the degree of reduction of the driving force according to the slip ratio. This improves both ride comfort and running stability of the vehicle.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

2 to 6 show an embodiment of the present invention, which is applied to a rear wheel drive vehicle.

First, to explain the configuration, reference numeral 1 shown in FIG. 2 is an accelerator potentiometer, which is configured to be linked to the depression of the accelerator pedal 2, and outputs an accelerator signal DA with a voltage corresponding to the amount of depression of the accelerator pedal 2. Output to the throttle valve control device 3.

The throttle valve control device 3 includes a microcomputer 4, an A/D converter 5, an F/V converter 6, and a motor drive circuit 7.
/D converter 5 and motor drive circuit 7 are connected to microcomputer 4. The microcomputer 4 includes an interface circuit 4a and a processing unit (CPU) 4.
b.RAM.

It has a storage device 4c such as a ROM, and the voltage output from the accelerator potentiometer 1 and the F/V converter 6 is
The signal is supplied to the arithmetic processing unit 4b via the /D converter 5 and the interface circuit 4a, and the arithmetic processing unit 4b is operated according to a program stored in advance in the storage device 4c.

The graphs shown in FIGS. 5 to 7 are stored in the storage device 4c.
Each is stored in its corresponding storage area in the form of a storage table. The memory table corresponding to the graph shown in FIG. 5 is a slip ratio-motor speed conversion table 4d, which converts the slip ratio S shown on the horizontal axis to the motor speed shown on the vertical axis. The motor speed is set to increase in proportion to the increase. The memory table corresponding to the graph shown in FIG. 6 is a stroke amount-target opening conversion table 4e, which converts the stroke (IL) of the accelerator pedal 2 shown on the horizontal axis to the target opening θ0 of the throttle valve shown on the vertical axis. The increase rate of the target opening θ0 is set to be larger than the increase rate of the stroke iL (so that it curves upward).In addition, the memory table corresponding to the graph shown in FIG. - A motor speed conversion table 4f, which converts the deviation Dir of the throttle valve opening shown on the horizontal axis into the motor speed shown on the vertical axis, so that the motor speed increases in proportion to the increase in the deviation Dir. It is set.

Furthermore, the storage device 4C has a reference slip ratio storage area 41 that stores a preset competitive slip ratio So.
A target opening storage area 4h in which the target opening θ0 of the throttle valve 17 is stored, a motor state specification storage area 41 in which a specified value specifying forward rotation, reverse rotation, or holding of the step motor 16 is stored, and an OC1 interrupt A startup cycle storage area 4j in which the startup cycle is stored, and a motor rotation direction storage area 4 in which a flag specifying the rotation direction of the step motor 16 is stored.
and an up/down counter 4m in which a value corresponding to the actual opening degree of the throttle valve 17 is stored, and the start cycle storage area 4j has an up/down counter 4m stored therein. 00 based on α'd period time
1 interrupt is executed.

The up/down counter 4m can count up by the number of steps required for the step motor 16 to drive the throttle valve 17 from the fully open state to the fully open state. It is set to 0 in the fully closed state.

Further, the F,/V converters 66, 2 are connected to the rear wheel rotation speed detector 10, which is a driving wheel rotation speed detection means for detecting the rotation speed of the rear right wheel 8 and the rear left wheel 9, which are driving wheels. A right front wheel rotation speed detector I3 and a left front wheel rotation speed are non-driving wheel rotation speed detection means that individually detect the rear wheel rotation speed signal DVr and the rotation speed of the front right wheel 11 and the left front wheel 12, which are non-driving wheels. Right front wheel and left front wheel rotation speed signal DVfr from the detector 14
, DVfl are respectively supplied. The rear wheel rotation speed detector 10 detects the rotation speed of the drive wheels by detecting the rotation speed of the differential gear 15 that transmits driving force to the rear left and right wheels 8 and 9, and detects a frequency according to the rotation speed. A rear wheel rotation speed signal DVr made of a pulse signal is output. Further, the right front wheel rotation speed detector 13 and the left front wheel rotation speed detector 14 directly detect the rotation speed of the front left and right wheels 11. Outputs rotation speed signals DVfr and DVfl, respectively.

The F/V converter 6 to which the rotational speed signals DVr, DVfr, and DVfl of the front and rear wheels are supplied converts these input signals into voltages according to their respective frequencies, and converts the rotational speed signals DV into A/V converters 6. The signal is sent to the D converter 5. A to which these rotational speed signals DV and the accelerator signal DA are supplied.
, /D converter 5 converts them into digital signals and outputs them to the microcomputer 4.

As a result, the microcomputer 4 detects the three input rotation speed detectors 1'0. 13. 14 and the accelerator signal DA from the accelerator potentiometer 1, a control process to be described later is executed, and a control signal C8 is output to the motor drive circuit 7 in accordance with the step rate S. Accordingly, the motor drive circuit 7 outputs a drive current to the step motor 16 based on the control signal supplied from the microcomputer 4, and causes the step motor 16 to rotate forward or reverse, or maintains a non-rotating state.

The rotation shaft 16a of the step motor 16 is constructed integrally with the rotation shaft of the throttle valve 17. For example, when the step motor 16 rotates in the normal direction, the throttle valve 17 is opened, and when the step motor 16 rotates in the reverse direction, the throttle valve 17 is opened. The valve 17 is closed.

The arithmetic processing unit 4b of the microcomputer 4 is R
For example, j
Arithmetic processing is performed according to a timer interrupt processing program that is executed every 00 m5ec, and based on the processing results, overflow counter interwoven interrupt processing (OCI interrupt) shown in FIG. 4, for example, is executed every startup cycle.

That is, in step (2), the rear wheel rotation speed signal DVr of the rear wheel rotation speed detector 10 is read, the rotation speed of the rear wheel 8.9 which is the drive wheel is calculated based on it, and this is stored as the drive wheel rotation speed Vr. It is temporarily stored in a predetermined storage area of the device 4C.

Next, proceed to step ■, and detect the right front wheel rotation speed detector 13.
reads the right front wheel rotational speed signal DVfr, calculates the rotational speed of the right front wheel 11, which is a non-driving wheel, based on it, and records this as the right non-driving wheel rotational speed Vfr and temporarily stores it in a predetermined storage area of the jl device 4C. .

Next, move to step ■ and check left front wheel rotation speed detector 1.
4 reads the left front wheel rotational speed signal DVf+, calculates the rotational speed of the left front wheel 12 which is a non-driving wheel based on it, and temporarily stores this in a predetermined storage area tα of the storage device 4c as the left non-driving wheel rotational speed Vfl. do.

Next, the process moves to step (2), and the right non-driving wheel rotational speed Vlr in step (2) and the left non-driving wheel rotational speed Vf in step (2) are determined.
Read out the left and right non-driving wheel rotation speed Vfr,
The rotational speed of the entire non-driving wheels is calculated based on Vfl, and this is temporarily stored in a predetermined storage area of the storage device 4c as the non-driving wheel rotational speed Vf. In this embodiment, the average value of the rotation speeds of the front left and right wheels 11 and 12 is used as the non-driven wheel rotation speed vr.

Next, proceed to step (2), read out the driving wheel rotational speed Vr in step (2) and the non-driving wheel rotational speed vr in step (2), and based on these front and rear wheel rotational speeds Vf and Vr, The slip rate S between the tires and the road surface of the entire vehicle that occurs between the tires No. 8 and 9 and the road surface is calculated.

Next, the process moves to slip (2), and the setting value So stored in advance in the reference slip ratio storage area 4g of the storage device 4c is
(for example, 0.2) and the slip rate S in step (3), and the slip rate S is the set value S.

Determine whether the value is greater than or not. As a result of the determination, if the slip ratio S is larger than the set value SO, control is performed to reduce the driving force of steps ■ to step (), while if the slip ratio S is smaller than the set value So, steps ◎ to [phase ] for normal driving force control.

In the driving force reduction control, first, in step (2), a command value O that designates the target opening degree θ0 of the throttle valve 17 to be fully closed is stored in the target opening degree storage area 4h of the storage device 4c.

Next, proceed to step (2), read the slip rate S of step (2), refer to the slip rate-motor speed conversion table 4d stored in the storage device 4c, and search for the motor speed from the slip rate S. .

Next, the process moves to step (2), where the current opening degree θ, which is the content of the amplifier down counter 4m (0 when fully closed) in the storage device 4c, and the target opening degree θ0 of step (2) are read out, and the target opening degree θ0 is read out. The deviation Dir of the current opening degree θ with respect to the target opening degree θ0 is calculated by subtracting the opening degree θ, and this is temporarily stored in a predetermined storage area of the storage device. In this case, since the target opening degree θ0 is always specified as 0 in step (2), the deviation Dir becomes 0 or a negative value. Therefore, in the driving force reduction control, the state of the step motor 16 is specified as either reverse rotation or holding.

In the next step [phase], the deviation Dir of step (2) is read out, and based on this it is determined whether to rotate the step motor 16 forward or reverse, or whether to maintain the current state, and a predetermined value representing the determination result is stored. It is temporarily stored in the motor state specification storage area 41 of the device 4c. The decision in this case is made by looking at the contents of the deviation Dir; when the deviation Dir is positive, the rotation is forward, when the deviation Dir is negative, the rotation is reversed, and when the deviation Dir is O, the current state is maintained. It is determined that

Next, the process moves to step (2), and based on the motor speed calculated in step (2) or step [phase], which will be described later, the activation cycle of the ○Cl interrupt, which will be described later, is determined, and the time is recorded in the activation cycle memory of the jQ device 4C. Set in area 4j. This activation cycle is determined by the motor speed determined based on the slip ratio S when the slip ratio S is larger than the set value SO, and is determined based on the deviation Dir when the slip ratio S is smaller than the set value SO. Depending on the motor speed, a time corresponding to the motor speed is set.

In the next step [phase], the recorded ta is similarly calculated based on the deviation Dir calculated in step
A flag specifying the rotation direction of the step motor 16 is set in the motor rotation direction jQ area 4k of the device 4C.

This ends the timer interrupt processing and returns to the main program, and then shifts to the OCI interrupt processing shown in FIG.

In addition, in the driving force normal control, first, in step 0,
The accelerator signal DA from the accelerator potentiometer l is read, the amount of depression of the accelerator pedal 2 is calculated based on it, and this is temporarily stored in a predetermined area of the storage device as a pedal stroke measurement.

Next, the process moves to step (2), reads the stroke measurement in step 0, refers to the stroke amount-target opening conversion table 4e stored in the storage device 4C, and calculates the target opening of the throttle valve 17 from the stroke IL. Search θ0.

Next, the process moves to step [phase], and similarly to step (2), the current opening degree θ of the up/down counter 4m of the storage device 4C and the target opening degree θO of step @ are read out.
The current opening degree θ is subtracted from the target opening degree θ0 to calculate the deviation Dir of the current opening degree θ with respect to the target opening degree θ0, and this is temporarily stored in a predetermined area 4g of the storage device. In this case,
Since the target opening degree θ0 is specified at step 0 to a value corresponding to the stroke iL, the deviation Dir is not only 0 or a negative value but also a positive value.

Next, move to step [phase] and deviation D of step @
If, read out the deviation stored in the storage device 4C -
The motor speed is retrieved from the deviation Dir with reference to the motor speed conversion table 4f. Then, the process moves to step [phase], and the processes of step [phase] to step 0 described above are executed.

Next, the OCI interrupt processing shown in FIG. 4 will be explained. As described above, this OC■ interrupt processing is executed according to the activation cycle of the time set in step 0.

That is, first, in step [phase], the step motor 16
It is determined whether or not to maintain the current rotational position and set it to non-rotation. The determination in this case is executed by looking at the contents of the motor state designation storage area 41 for step [phase]. As a result of this determination, if it is determined that the current rotational position of the step motor 16 is to be maintained, the current OCT interrupt processing is finished, and this OCI interrupt processing is executed again according to the startup cycle of the OCI interrupt processing. Either execute the process or return to the main program and execute the timer interrupt process shown in FIG. 3 after a predetermined time.

On the other hand, in step [phase], if it is determined that the current rotational position of the step motor 16 is not maintained, the process moves to step 0 and it is determined whether or not to rotate the step motor 16 in the normal direction. In this case, the determination is also made in step [
Similar to step [phase], this is done by looking at the contents of the motor state specification storage area 41 for step [phase]. As a result of that judgment,
To rotate the step motor 16 in the forward direction (in the direction of opening the throttle valve 17), proceed to step @, add 1 to the current value θ of the amplifier down counter 4m, and then proceed to step ■, while rotating the step motor 16. When performing a reverse rotation (direction in which the throttle valve 17 is closed), the flow proceeds to step 0, where 1 is subtracted from the current value θ of the up/down counter 4m, and the flow proceeds to step (2).

In this step (2), a drive signal C3 for rotating the step motor 16 in the forward direction by one step, or a drive signal C3 for rotating the step motor 16 in the reverse direction by one step is provided.
8 is output, and this ends the current oct interrupt processing.

The processing of steps ■ to step ■ above constitutes a slip ratio calculation means, the processing of step The step motor 16 constitutes a throttle valve control means.

Next, the effect will be explained.

Assuming that the vehicle is currently running, when the timer interrupt process shown in FIG. 3 is executed at predetermined intervals in this state, first, in step Calculate the wheel rotation speed Vr, read the right front wheel rotation speed signal DVfr in step 2, calculate the right non-driving wheel rotation speed Vfr based on this, and read the left front wheel rotation speed signal DVfl in step Based on this, the left non-driving wheel rotation speed Vfl is calculated.

Next, the process moves to step (2), and the right non-driving wheel rotational speed Vfr in step (2) and the left non-driving wheel rotational speed Vf in step (2) are determined.
1 is read out, the non-driving wheel rotation speed Vf is calculated based on these, and in the next step (2), based on the driving wheel rotation speed Vr of step (2) and the non-driving wheel rotation speed Vf of step (2),
Calculate the slip rate S between the tire and the road surface for the drive wheels (■) and (■).

Then, proceeding to step (3), read the set value SO of the reference slip ratio storage area 4f provided in the storage device 4c,
The slip rate S calculated in step ■ is set to this set value SO.
Compare it to determine its size.

At this time, the drive wheels 8.9 are in a slip state [(S
= 0.2 or more), then S> in step ■
Since it is determined to be So, the process moves to the driving force reduction control in step ■ and below, and first, in step ■, a command value 0 for fully closing the target opening θ0 is set in the target opening storage area 4h. Next, the process moves to step (2), and the motor speed is searched based on the slip ratio S calculated in step (2).

In this case, the motor speed to be searched is a value corresponding to the magnitude of the slip ratio S, so when the slip ratio S is large, a high speed value is obtained, and when the slip ratio S is small, a low speed value is obtained. In the next step (2), a deviation Dir is calculated based on the target opening degree θ0 of step (2) and the current opening degree θ of the up/down counter 4m.

In this case, assuming that the current opening degree θ of the throttle valve 17 is wide open and the engine is generating a large driving force,
Since the deviation Dir in step ■ is a large negative value, reversal of the motor is determined in step [phase], and in the next step ■, a short startup cycle is set according to the magnitude of the slip ratio S. Furthermore, a flag regarding reversal is sent at step @.

As a result, following this timer interrupt processing, the OCT shown in FIG.
When the interrupt processing is executed, first, it is determined in step [phase] that the morph is not held, and then, in step ■, it is determined that the motor is to be reversed, so in step 0, the current value θ of the up/down counter 4m is Subtract 1 and step ■
Then, a control signal C3 for rotating the step motor 16 by one step in the reverse direction is output to the motor drive circuit 7, and the motor drive circuit 7 outputs a motor drive signal to the step motor 16. As a result, the step motor 16 rotates one step, and the throttle valve 17 is closed by the rotation angle.

Then, when the next 001 interrupt is started due to the short activation period set in step 0, step [phase]
And after step ■, subtract 1 from the current value θ of up/down counter 4m in step [phase], and proceed to the next step ■
Then, a motor drive signal for rotating the step motor 16 by one step in the reverse direction is outputted to the step motor 16 via the motor drive circuit 7. As a result, the step motor 16 rotates one step, and the throttle valve 17 is further closed by the rotation angle.

This OCI interrupt continues until the predetermined time required for one cycle of the timer interrupt processing shown in FIG. 3 has elapsed.

After that, due to changes in the road surface, the slip rate S changes to the set value S.
When the motor speed decreases to around o, the motor speed is searched in the same way as described above based on the current slip rate S in step ■ after the processing of steps ■ and step ■. Since it is small, a correspondingly relatively low motor speed is searched for. Therefore, in this case, since a relatively long activation period is set in step 0, the step motor 16 is rotationally driven at a comparatively low speed in step (2) in the OCI interrupt processing in FIG. Throttle/torre valve 17 is closed relatively late.

Note that if the slip rate S is less than the set value SO, the drive force normal control is performed, and the stroke IL of the accelerator pedal 2 is first read in step 0, and the stroke amount - target opening degree conversion is performed in the next step ■. The target opening degree θ0 corresponding to the stroke amount is searched with reference to the table 4e. Then, in step (2), the deviation Dir is calculated based on the target opening θ0 and the current opening θ, and in the next step 0, the deviation Dir is calculated with reference to the deviation-motor speed conversion table 4f.
The motor speed will be searched according to the motor speed.

Thereafter, the current timer interrupt is terminated through the processing from step @ to step @ described above.

Therefore, in this driving force normal control, the deviation D based on the target opening degree θ0 corresponding to the stroke IL of the accelerator pedal 2
The step motor 16 operates at a speed according to the ir.
It is rotated aJ in the forward or reverse direction or held at the current position.

Accordingly, in the present invention, when the slip state of the vehicle (driving wheels) is equal to or higher than the set slip ratio So, the speed of the step motor 16 is changed according to the calculated slip knob ratio S to prevent excessive slip. At times, the throttle valve 17 is closed early to speed up the reduction in driving force, while when the slip is small, the throttle valve 17 is closed relatively late to slow down the reduction in driving force, thereby improving running stability in the event of excessive slip. At the same time, it is possible to suppress rapid vehicle deceleration during low slip, thereby improving the ride comfort of the vehicle.

It should be noted that the throttle valve control device 3 is not limited to the above-mentioned configuration, and can be configured with electronic circuits such as a subtraction circuit, a comparison circuit, and a logic circuit. Further, in the above embodiment, the step motor 1 is used as the throttle valve control means.
6 is used, but the present invention is not limited to this. For example, the motor may be constructed of a digital servo motor and a row encoder attached to its rotating shaft.

Further, in the above embodiment, an example of a rear wheel drive vehicle has been described, but the present invention can of course be applied to a front wheel drive vehicle.

[Effects of the Invention] As described above, according to the present invention, the drive wheel rotation speed detection means, the non-drive wheel rotation speed detection means, and the tire-road surface detection means based on the rotation speeds of the drive wheels and the non-drive wheels. slip ratio calculation means for calculating a slip ratio between the two; slip ratio determination means for determining whether the slip ratio is greater than a set value; and a slip ratio determining means for determining whether the slip ratio is greater than the set value; The vehicle driving force control device is equipped with a throttle valve control means that continuously controls the driving force according to the slip ratio to reduce the driving force, so that the vehicle does not exceed a predetermined level.
In the second slip state, when the slip ratio is large, the closing speed of the throttle valve can be increased, while when the slip ratio is relatively small, the closing speed of the throttle valve can be decreased.

Therefore, in the event of a large slip, the degree of reduction in driving force is reduced quickly.
It is possible to slow down the degree of reduction in driving force during small slips, thereby ensuring vehicle running stability during large slips, as well as preventing discomfort and jerky vibrations caused by excessive vehicle deceleration during small slips. This has the effect of improving the ride comfort of the vehicle.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the basic configuration of the present invention, Fig. 2 is a schematic explanatory drawing showing an embodiment of the invention, and Figs. A flowchart showing an example, FIG. 5 is a graph showing the relationship between the motor speed and the slip ratio S, FIG. 6 is a graph showing the relationship between the target opening degree θ0 of the throttle valve and the stroke iL of the accelerator pedal, and FIG. is a graph showing the relationship between motor speed and opening deviation Dir. ■・・・Accelerator potentiometer, 2...
...Accelerator pedal, 3...Throttle valve control device, 4...Microcomputer, 4a...
...Interface circuit, 4b...Arithmetic processing unit, 4C...Storage device, 5...A
/D converter, 6...F/V converter, 7...
...Motor drive circuit, 8.9... Rear wheel (drive wheel), 10... Rear wheel rotation speed detector (drive wheel rotation speed detection means), 11.12... ...Front wheel (non-drive wheel)
, 13.14...Front wheel rotation speed detector (non-driven wheel rotation speed detection means), 16...Step motor,
17... Throttle valve

Claims (2)

[Claims] (1) Drive wheel rotation speed detection means that detects the rotation speed of the drive wheels of the vehicle and outputs the detection signal, and non-drive wheel rotation speed detection means that detects the rotation speed of the non-drive wheels and outputs the detection signal. means, a slip ratio calculation means for calculating a slip ratio between the tire and the road surface based on the detection signals from the driving wheel rotation speed detection means and the non-driving wheel rotation speed detection means, and a calculation result of the slip ratio calculation means. a slip rate determining means for determining whether or not the slip rate is greater than a set value based on the slip rate; 1. A vehicle driving force control device comprising: throttle valve control means for controlling the closing speed of the throttle valve to reduce the driving force. (2) Claim (1) characterized in that, when the slip ratio is larger than the set value, the throttle valve control means increases the closing speed of the throttle valve as the slip ratio increases. The vehicle driving force control device described above.