JP2003269591A - Road surface condition detecting apparatus and control device for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the clamping force of a continuously variable transmission suited for the actual condition of a road surface by accurately determining the condition of the road surface. <P>SOLUTION: The continuously variable transmission where torque volume varies depending on a clamping force for clamping a torque transmitting member is positioned between a power source and a driving wheel. A device for detecting the condition of a road surface and controlling the continuously variable transmission according to changes in the number of output rotations of the continuously variable transmission or changes, depending on the condition of the road surface, in the number of rotations of rotating members including the driving wheel connected to the output side of the transmission, includes a processing means (step S2) for performing a band-pass filter process on the detected values of the numbers of rotations, an integrating means (step S4) for performing time window integration on the values obtained through the band-pass filter process, and a road surface condition determining means (step S11) for determining the condition of the road surface according to the values of the time window integration. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a condition of a road surface and a device for controlling a belt type or traction type (toroidal type) continuously variable transmission.

[0002]

2. Description of the Related Art A transmission of this type is mounted on a vehicle and is controlled so as to set the engine speed to an optimum speed according to the running condition, thereby maintaining fuel efficiency while maintaining the power performance of the vehicle. It is an effective way to improve. Therefore, torque is input to the continuously variable transmission from a power source such as an engine, but the torque acting between the drive wheels and the road surface changes variously while the vehicle is running. Including the resulting inertial torque, torque acts on the continuously variable transmission from the output side as well, and the torque varies in various ways.

The continuously variable transmission is a transmission that transmits torque through frictional force, shearing force of traction oil, etc. as described above, and does not transmit torque by a meshing mechanism, and therefore exceeds the torque capacity. When the torque is applied from the input side or the output side, or when the torque is temporarily increased due to some disturbance factor, slippage occurs. Excessive such slippage can damage the continuously variable transmission. On the other hand, if the clamping pressure is increased to avoid slippage, the power transmission efficiency may decrease and the fuel efficiency of the vehicle may deteriorate.

Therefore, it is necessary to detect the state of the road surface, which is a factor of fluctuation of the torque on the output side, for controlling the clamping pressure in the continuously variable transmission, and it is possible to accurately detect or determine the state of the road surface. If possible, the chances of reducing the clamping pressure while avoiding slippage increase, and the fuel efficiency of the vehicle can be improved.

On the other hand, conventionally, as a device for detecting fine projections (irregularities) on the road surface, a device for bandpass filtering a wheel speed signal is described in Japanese Patent Laid-Open No. 6-163964. The device described in this publication uses bandpass filter processing of the output signal of the sensor that detects the rotation of the wheels to extract the variation in wheel speed, and determines the fine irregularities on the road surface based on the variation, and It is configured to change the characteristics of the suspension device based on the result.

[0006]

In the device described in the above publication, since the signal obtained by the sensor includes signals such as noise and vehicle acceleration, the signals are removed to remove the wheel speed. It is a device configured to take out a fluctuation amount according to the state of the road surface. Then, in this device, the unevenness of the road surface is judged by comparing the band-pass filtered signal with a predetermined threshold value.

The threshold value is set to a value according to the accuracy of the signal processing device. If the threshold value is reduced, even a slight fluctuation in the rotation speed that does not depend on the condition of the road surface causes unevenness on the road surface. The possibility of misjudgment such as judgment is high. If the threshold value is increased in order to avoid such an erroneous judgment, the road surface condition will be judged only by large fluctuations in rotation, so it is necessary to judge a road surface with a series of minute irregularities such as a cobblestone road. I can't. Alternatively, it may take time to make the determination, and the torque acting on the continuously variable transmission may fluctuate greatly during that time, and at that time, slippage may occur.

The present invention has been made in view of the above technical problems, and is a device capable of accurately detecting or determining the condition of a road surface, and a pinion of a continuously variable transmission according to the condition of the road surface. It is an object of the present invention to provide a device capable of controlling pressure.

[0009]

In order to achieve the above object, the present invention is based on a value obtained by further integrating a value obtained by filtering a wheel speed or a rotation speed having a constant relationship with the wheel speed. The present invention is characterized in that the condition of the road surface is detected, and the continuously variable transmission is controlled based on the condition of the road surface thus detected or determined. Specifically, the invention of claim 1 filters the detected value of the rotational speed of the wheel or the rotational speed of a predetermined rotating member that rotates in a fixed relationship with the wheel, and based on the filtered value. A road surface state detecting device for detecting a road surface state is provided with an integrating means for integrating the filtered values, and a road surface state determining means for determining a road surface state based on the integrated value. It is a device.

The integrating means may be means for performing time window integration of the filtered values, as described in claim 2.

Further, the road surface condition judging means is characterized in that:
As described in, when the integrated value is equal to or greater than a predetermined value that is determined in advance, the road surface is determined to be a non-good road, and when the integrated value is less than a predetermined value that is determined in advance, the road surface is determined to be a good road. It can be a means.

Therefore, in each of the first to third aspects of the present invention, the detected value of the wheel speed or the rotational speed corresponding thereto is filtered, and the filtered value is integrated. The integration is, for example, time window integration, and the road surface condition is determined based on the integrated value. As a result, since a minute amount of rotational fluctuation is incorporated in the integrated value, it is possible to determine even a minute change in the road surface as the road surface state, and the road surface is not determined only by such a minute change. False determination can be avoided or suppressed, and road surface determination can be made accurate as a whole. In other words, it is possible to accurately detect or determine the road surface condition by removing or suppressing the influence of noise.

Further, according to the invention of claim 4, in the structure of claim 2 or 3, further comprising an anneal processing means for annealing the time window integral value, and the road surface condition determining means is the averaging means. An apparatus characterized in that it is configured to determine a road surface state based on the time window integral value that has been annealed by the processing means.

Therefore, according to the invention of claim 4, the vibration component contained in the time window integral value is removed by the smoothing process. As a result, the smoothed time window integral value becomes a value that better reflects the road surface condition, and the accuracy of the road surface condition determination is improved.

On the other hand, according to a fifth aspect of the present invention, a continuously variable transmission whose torque capacity changes in accordance with the clamping pressure that clamps the torque transmitting member is disposed between the power source and the drive wheels, and the continuously variable transmission is provided. Based on the road surface condition for controlling the continuously variable transmission based on the change in the output speed of the machine or the rotation speed of the rotating member including the drive wheel connected to the output side of the continuously variable transmission according to the road surface condition. In a control device for a transmission, a processing means for filtering the detected value of the rotational speed, an integrating means for integrating a value obtained by the filtering in a time window, and a road surface condition based on the time window integrated value. And a road surface condition determining means for determining.

Therefore, in the invention of claim 5, the output speed of the continuously variable transmission or the output speed up to the drive wheels is detected, the detected value is filtered, and the filtered value is further processed. Is time window integrated. Then, the road surface condition is determined based on the integrated value, and the clamping pressure is controlled based on the determination result. As a result, a minute amount of rotational fluctuation is captured in the integrated value,
A small change in the road surface can be judged as the road surface condition, and the road surface is not judged only by such a slight change, so erroneous judgment can be avoided or suppressed, and the road surface can be judged accurately as a whole. The pinching pressure control based on the road surface condition becomes accurate.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, when the road surface state determining means determines that the road surface state is a poor road, the sandwiching is performed more than when the road surface state is a good road. The control device further comprises a clamping pressure control means for increasing the pressure.

Therefore, in the sixth aspect of the present invention, when the good road is determined, the clamping pressure is reduced as compared with the case where the determination is not made. Therefore, when the possibility of torque fluctuation due to so-called disturbance is low, the clamping pressure of the continuously variable transmission is reduced, the power transmission efficiency is improved, and the fuel efficiency of the vehicle is improved.

Further, the invention of claim 7 is the invention of claim 5 or claim 6, further comprising an anneal processing means for annealing the time window integral value, and the road surface condition determining means is characterized in that The control device is configured to determine a road surface state based on the time window integral value that has been annealed by the annealer.

Therefore, in the seventh aspect of the invention, the vibration component contained in the time window integral value is removed by the smoothing process. As a result, the smoothed time window integral value becomes a value that better reflects the road surface condition, and the accuracy of the road surface condition determination and the clamping pressure control based on it is improved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described based on specific examples. First, a drive system of a vehicle and a control system thereof which are the subject of the present invention will be described. FIG. 7 schematically shows a drive system including the belt type continuously variable transmission 1 as a transmission. The machine 1 includes a forward / reverse switching mechanism 2 and a fluid transmission mechanism 4 with a lockup clutch 3.
Is connected to the power source 5 via.

The power source 5 is composed of an internal combustion engine, or an internal combustion engine and an electric motor, or an electric motor,
The point is a drive member that generates power for traveling. In the following description, the power source 5 will be referred to as the engine 5. Further, the fluid transmission mechanism 4 has, for example, a configuration similar to that of a conventional torque converter, and includes a pump impeller rotated by the engine 5, a turbine runner arranged so as to face the pump impeller, and a stator arranged therebetween. The turbine runner is rotated by supplying the spiral flow of the fluid generated by the pump impeller to the turbine runner, and the torque is transmitted.

In the transmission of torque through such a fluid, an unavoidable slip occurs between the pump impeller and the turbine runner, which causes a reduction in power transmission efficiency. Therefore, a member on the input side such as the pump impeller. A lock-up clutch 3 is provided for directly connecting an output side member such as a turbine runner. The lockup clutch 3 is configured to be controlled by hydraulic pressure, and is controlled to be in a completely engaged state, a completely released state, and a slip state which is an intermediate state between these states, and the slip rotation speed thereof is appropriately controlled. You can do it.

The forward / reverse switching mechanism 2 is a mechanism adopted because the rotation direction of the engine 5 is limited to one direction, and outputs the input torque as it is and reverses the output. Is configured to. In the example shown in FIG. 7, a double pinion type planetary gear mechanism is adopted as the forward / reverse switching mechanism 2. That is, the ring gear 7 is arranged concentrically with the sun gear 6, and the pinion gear 8 meshed with the sun gear 6 and the pinion gear 9 meshed with the pinion gear 8 and the ring gear 7 are arranged between the sun gear 6 and the ring gear 7. The pinion gears 8 and 9 are rotatably and revolvably held by the carrier 10.

A forward clutch 11 for integrally connecting the two rotating elements (specifically, the sun gear 6 and the carrier 10) is provided. Further, a reverse brake 12 that reverses the direction of the output torque by selectively fixing the ring gear 7 is provided.

The continuously variable transmission 1 has the same structure as a conventionally known belt type continuously variable transmission, and each of a driving pulley 13 and a driven pulley 14 arranged in parallel to each other is
It is composed of a fixed sheave and a movable sheave that is moved back and forth in the axial direction by hydraulic actuators 15 and 16. Therefore, the groove width of each pulley 13, 14 changes by moving the movable sheave in the axial direction, and accordingly, the winding radius of the belt 17 wound around each pulley 13, 14 (the effective diameter of the pulleys 13, 14). ) Changes continuously, and the gear ratio changes continuously. Then, the drive pulley 13 is used for the forward / reverse switching mechanism 2
Is connected to a carrier 10 which is an output element in.

The hydraulic actuator 16 of the driven pulley 14 receives hydraulic pressure (line pressure or its correction pressure) corresponding to the torque input to the continuously variable transmission 1 via a hydraulic pump and hydraulic control device (not shown). Is being supplied. Therefore, each sheave in the driven pulley 14 sandwiches the belt 17 so that tension is applied to the belt 17 and a clamping pressure (contact pressure) between the pulleys 13 and 14 and the belt 17 is secured. . On the other hand, the hydraulic actuator 15 in the drive pulley 13
Is supplied with pressure oil according to the gear ratio to be set, and the groove width (effective diameter) is set according to the target gear ratio.

The driven pulley 14 is connected to a differential 19 via a gear pair 18, and torque is output from the differential 19 to the drive wheels 20. Therefore, in the above drive system, the lockup clutch 3 and the continuously variable transmission 1 are arranged in series between the engine 5 and the drive wheels 20.

Various sensors are provided to detect the operating state (running state) of the vehicle in which the continuously variable transmission 1 and the engine 5 are mounted. That is, a turbine rotation speed sensor 21 that detects the input rotation speed (rotation speed of the turbine runner) to the continuously variable transmission 1 and outputs a signal, and an input rotation speed that detects the rotation speed of the drive pulley 13 and outputs a signal. A sensor 22, an output rotation speed sensor 23 that detects the rotation speed of the driven pulley 14 and outputs a signal, and a wheel speed sensor 24 that detects the rotation speed of the drive wheel 20 and outputs a signal are provided. Also, although not particularly shown,
Accelerator opening sensor that detects the amount of depression of the accelerator pedal and outputs a signal, throttle opening sensor that detects the opening of the throttle valve and outputs a signal, brake sensor that outputs a signal when the brake pedal is depressed Etc. are provided.

Control of engagement / release of the forward clutch 11 and the reverse brake 12 and the belt 17
An electronic control unit (CVT-ECU) 25 for a transmission is provided to control the clamping pressure of the gear, the gear ratio, and the lockup clutch 3. The electronic control unit 25 is mainly composed of a microcomputer as an example, performs an operation in accordance with a predetermined program based on input data and previously stored data, and performs various states such as forward and reverse or neutral. The required clamping force setting, the gear ratio setting, the engagement / disengagement of the lockup clutch 3, and the slip rotation speed are controlled.

Here, an example of data (signal) input to the transmission electronic control unit 25 will be shown. The continuously variable transmission 1
Of the input rotation speed Nin, the output rotation speed N of the continuously variable transmission 1
Signals of o are input from the corresponding sensors (not shown). Further, from an engine electronic control unit (E / G-ECU) 26 that controls the engine 5, an engine speed Ne signal, an engine (E / G) load signal, a throttle opening signal, an accelerator pedal (not shown). No)
The accelerator opening signal, which is the amount of depression of the pedal, is input.

According to the continuously variable transmission 1, the engine speed, which is the input speed, is continuously changed (in other words, continuously).
Since it can be controlled, the fuel economy of a vehicle equipped with this can be improved. For example, the target drive force is obtained based on the required drive amount represented by the accelerator opening degree and the vehicle speed, and the target output required to obtain the target drive force is obtained based on the target drive force and the vehicle speed. The engine speed for obtaining the target output with the optimum fuel economy is obtained based on a map prepared in advance, and the gear ratio is controlled so as to become the engine speed.

In order not to impair such an advantage of improving fuel economy, the power transmission efficiency of the continuously variable transmission 1 is controlled to a good state. Specifically, the torque capacity of the continuously variable transmission 1, that is, the belt clamping pressure can be transmitted to the target torque determined based on the engine torque, and the belt clamping pressure is as low as possible within a range where the belt 17 does not slip. Controlled.

On the other hand, the torque applied to the drive system including the continuously variable transmission 1 suddenly changes due to sudden braking, sudden acceleration, idling of a tire riding on a falling object or a step, or when the tire slips. In that case, the torque capacity of the continuously variable transmission 1 is relatively insufficient, and the belt 17 is likely to slip. As described above, when the continuously variable transmission 1 slips and is partially worn, this may damage the continuously variable transmission 1. Therefore, the device of the present invention detects a road surface condition that is a disturbance to the control of the clamping pressure of the continuously variable transmission 1 and executes the control for increasing the clamping pressure based on the road surface condition.

Here, the control for increasing the clamping pressure means
Based on the running state or the drive state of the drive system at that time, the control is to increase and increase to a pressure higher than the normally set clamping pressure (pressure with an increased safety factor) with a certain safety factor.

FIG. 1 is a flow chart showing an example of the pinching control carried out by the road surface state detecting and controlling apparatus by the road surface state detecting apparatus of the present invention. In the example shown here, first, the output speed No is read (step S
1). This output rotation speed No is specifically the rotation speed of the driven pulley 14 or a rotating member such as a driven shaft integrated with the driven pulley 14, or the rotation speed or drive of the output-side rotating member having a fixed relationship with this. The number of rotations of the wheel 20. This number of revolutions changes according to changes in the vehicle speed, changes according to the condition of the road surface such as unevenness, and further includes components such as noise. Therefore, for example, FIG.
The signal is as shown in.

Then, band-pass filter processing is applied to the detected rotational speed (step S2). This is a process of removing the change component of the rotation speed due to the change of the vehicle speed, for example, and the signal obtained as a result is as shown in FIG. The absolute value ((C) in FIG. 2) of the signal processed in this way is taken (step S3), and n pieces of data traced back from the current time are integrated (step S).
4). The integration in step S4 is a time window integration at a time corresponding to n pieces of data. On the other hand, the amount of change in the detected rotational speed No or the rotational acceleration ΔNo is calculated (step S5).

After performing the above calculation, the flag F is judged (step S6). This flag F is
This is set to "1" when a so-called disturbance is determined and the clamping pressure is set to a high level. The flag is set to "0" when the pinching pressure is set to a low level because the so-called disturbance is converged or the disturbance is not determined.

When "F = 0" is determined in step S6, the clamping pressure is set to the normal level, and the inertia torque at the time of re-grip after tire slip and the negative torque due to sudden braking cannot be dealt with. Therefore, it is determined whether or not there is a disturbance such as tire slip or sudden braking (step S7). That is, it is determined whether or not the rate of change (acceleration) ΔNo of the output rotational speed No is equal to or greater than the first threshold value ΔNo1 which is a relatively large value.

When the drive wheel 20 slips, the rotational speed of the drive wheel 20 and the rotational speed of the driven pulley 14 of the continuously variable transmission 1 to which the drive wheel 20 is connected rapidly increase, which is the output rotational speed. It appears as an increase in the acceleration ΔNo of No. Further, when sudden braking is performed, the rotation speed of the drive wheel 20 and the rotation speed of the driven pulley 14 of the continuously variable transmission 1 to which the drive wheel 20 is connected are rapidly reduced. It appears as an increase in the absolute value of the acceleration ΔNo. Further, a similar situation occurs when riding on a falling object on the road surface or passing through an uneven portion, and these so-called disturbances can be determined based on the rotational acceleration.

Therefore, if the determination in step S7 is affirmative, it means that the rotational speed on the output side is rapidly changing due to the disturbance, so the flag F is set to "1" (step S8). Then, the engine torque is reduced (down) (step S9). This is to reduce the torque acting on the continuously variable transmission 1 from its input side. This control can be executed, for example, by retarding the ignition timing of the engine 5.

Then, an instruction to set the clamping pressure to a high level is output (step S10). This high-level clamping force is, in short, important even if the torque on the output side or the torque acting on the continuously variable transmission 1 is largely changed due to the disturbance as described above. It is a clamping force that does not cause slippage. Specifically, for example, the line pressure that is the original pressure in the continuously variable transmission 1 is supplied to the actuator 16 in the driven pulley 14.

That is, step S9 and step S1
The control of 0 is the corresponding control when the disturbance is detected,
The torque acting on the continuously variable transmission 1 is reduced, and the torque capacity of the continuously variable transmission 1 or the excess amount of the transmission torque with respect to the minimum transmission torque (a margin of the transmission torque) within the range where slippage does not occur is possible. Increase.

On the other hand, when a negative determination is made in step S7 because no disturbance is detected, the integrated value (the time window integrated value of the rotational speed) integrated in step S4 is set to a predetermined value. It is determined whether or not it has exceeded (step S11). As described above, this integrated value is obtained by bandpass filtering the detected value of the rotational speed of the driven pulley 14 or a member rotating in a fixed relationship with the driven pulley 14 and performing time window integration. It is a value that also includes. In other words, the value reflects even slight irregularities on the road surface. Then, the value increases / decreases with each time window, and eventually reflects the state of the road surface that has traveled from the current time point to the predetermined time period.

Therefore, when the affirmative determination is made in step S11 because the integrated value exceeds the predetermined value, it means that the rotation fluctuation based on the condition of the road surface is large to some extent and continues. As a result, it is determined that the road surface is a so-called poor road (or bad road). Therefore, in this case, the process proceeds to step S10 described above, and an instruction to set the clamping pressure to a high level is output. That is, there is a possibility that the rotation of the drive wheels may change due to traveling on a poor road and the negative torque may increase accordingly.
In order to prevent the continuously variable transmission 1 from slipping due to an increase in torque, the clamping pressure is increased.

Since the continuously variable transmission 1 has not slipped and the vehicle is still traveling, the control for reducing the engine torque is not executed. In addition, the predetermined value (threshold value) in step S11 that serves as a criterion for determining whether the road is good or bad.
It is optional to set the hysteresis on. By setting a hysteresis in the threshold value, it is possible to prevent hunting when switching the clamping pressure between a high level and a normal level.

On the other hand, if the determination in step S11 is negative, it is determined that the road surface has no unevenness or is a so-called good road with little unevenness, and therefore the clamping pressure is set to the normal level. The instruction is output (step S12). This normal level clamping pressure is a clamping pressure preset as a pressure lower than the high level clamping pressure described above. Therefore, the clamping pressure does not become excessive with respect to the torque acting on the continuously variable transmission 1. In other words, the clamping pressure can be set as low as possible, so that the power of the continuously variable transmission 1 is reduced. The transmission efficiency is improved and the fuel consumption can be improved.

In step S6 described above, "F = 1"
If the determination is satisfied, then the clamping pressure is set to a high level in preparation for the disturbance. Therefore, it is determined whether or not this high level state should be continued. Specifically, the rotational acceleration ΔNo is initially a positive value, and whether or not the rotational acceleration ΔNo becomes a predetermined value ΔNo0 or more via a negative value, or the rotational acceleration ΔNo is initially a negative value and then a predetermined value. It is determined whether the value ΔNo0 or more is reached (step S13).

In the former example, when the drive wheel 20 slips or idles during acceleration to increase its rotational speed, then the gripping force is recovered to decrease the rotational speed, and then the rotational speed returns to a predetermined value. Is. The latter example is a case where the vehicle is suddenly braked during traveling to reduce the rotational speed of the wheels, and then the braking is released or the braking force is relaxed to return to a predetermined rotational speed.

Therefore, if the determination in step S13 is negative, it means that the change in the rotational speed due to the disturbance or the action of the inertia torque associated therewith has not ended, and therefore the process returns without performing any particular control. That is, the clamping force is maintained at a high level.

On the other hand, if the determination in step S13 is affirmative, it means that the fluctuations in the rotational speed and the torque due to the disturbance have converged, so that the engine torque that has been reduced is lower than that before the reduction control. Is restored to the torque (step S14). Further, control for returning the raised clamping pressure to the normal level is executed (step S
15). Then, the flag F is set to "0" (step S16).

Therefore, according to the control device of the present invention which performs the control shown in FIG. 1, the detection signal by the rotational acceleration of any rotating member on the so-called output side of the continuously variable transmission 1 is only band-pass filtered. In addition to the above, the processed value is integrated, the road surface state is determined based on the integrated value, and the clamping pressure is set higher than normal or set to normal pressure according to the result of the determination. Therefore,
The road surface condition can be detected or determined more accurately than ever before, and the clamping pressure suitable for the actual road surface condition can be set. Therefore, slippage in the continuously variable transmission 1 can be avoided in advance, and at the same time, the pinching pressure can be made as low as possible to improve the fuel efficiency of the vehicle.

Next, another control example executed by the control device of the present invention will be described with reference to the flow chart shown in FIG. The control example shown in FIG. 3 is obtained by partially modifying the control example shown in FIG. 1 described above, and the clamping pressure set when there is no disturbance and when a good road is determined is set to the normal level. This is an example of a configuration in which the low pressure level and the low pressure level are set separately. Therefore, the control example shown in FIG. 3 includes steps S11 and S shown in FIG.
12 is changed and the other steps are the same as those in FIG. 1, so only the parts different from those in FIG. 1 will be described, and the other control steps will be given the same reference numerals in FIG. 3 as those in FIG. Omit it.

When the absolute value of the rotational acceleration ΔNo is smaller than the predetermined value ΔNo1 which is the first reference value, step S7 is executed.
If the determination result in step S11 is negative, it is determined whether the absolute value of the rotational acceleration ΔNo is less than the predetermined value ΔNo1 and is equal to or larger than the second reference value ΔNo2 (step S11).
1). If the determination in step S111 is affirmative, the rotational fluctuation due to the disturbance has not occurred, but the rotational acceleration ΔNo is somewhat large, so the clamping pressure is set to a high level without reducing the engine torque. To do. That is, the process proceeds to step S10, and a command for setting a high level clamping pressure is output. This step S
111 may be replaced with step S11 shown in FIG.

When a negative determination is made in step S111, it is determined whether or not the rotational acceleration ΔNo is equal to or larger than a predetermined value ΔNo3 which is a third reference value (<ΔNo2) (step S112). This step S112 is for determining whether the traveling state is a steady traveling state without disturbance or a quasi-steady traveling state.

For example, as shown in FIG. 4, a region of a predetermined input torque width or an engine load width centering on the road load is predetermined as a quasi-steady state traveling region, and the engine load is set within the region. Is the maximum rotational acceleration that occurs when the value changes, or a value determined based on the maximum rotational acceleration is the predetermined value ΔNo3. In FIG. 4, the hatched region as the region where the engine load is low is the region where the clamping pressure is determined and set with the engine load or the input torque as a predetermined constant value.

Therefore, if the affirmative determination is made in step S112, whether the engine load is relatively large,
Alternatively, on the contrary, the clamping pressure is set to the normal level because it is relatively small and is not in the quasi-steady running state (step S113). On the other hand, if the determination in step S112 is negative, the rotational acceleration is the predetermined value ΔNo3.
Since it is smaller and is in the steady running state or the quasi-steady running state, it is determined whether or not the integrated value exceeds a predetermined value (step S114). This is a determination step similar to step S11 shown in FIG.

If a negative determination is made in step S114, it is determined that the vehicle is traveling on a smooth and good road with few irregularities on the road surface, and the traveling state at that time is a steady state or a quasi-steady state. An instruction to set the clamping pressure to a low level is output (step S115). This low level is a pressure lower than the normal level described above within a range in which the continuously variable transmission 1 does not slip. In other words, it is a pressure in which the excess amount (margin width) of the clamping pressure with respect to the minimum clamping pressure at which slippage does not occur is reduced. So in this case,
The power transmission efficiency of the continuously variable transmission 1 and the fuel efficiency of the vehicle are improved.

On the other hand, if the determination in step S114 is affirmative, the rotational speed has changed due to the influence of the road surface, and the road surface is a poor road. Therefore, in this case, it is determined whether or not the rotational acceleration ΔNo is greater than or equal to the fourth reference value ΔNo4, which is a smaller value (step S).
116). Here, if the relationship between the reference values for the determination of the rotational acceleration ΔNo is shown, ΔNo1>ΔNo2>ΔNo3> ΔNo4
Is.

Therefore, in step S116, it is determined whether or not the change in the output speed or the output-side speed, which has a constant relationship with the output speed, is considerably small, in other words, the rotational fluctuation is almost constant even though the vehicle is traveling on a poor road. It is judged whether or not there is. Therefore, if the determination in step S116 is negative, the torque acting on the continuously variable transmission 1 is unlikely to change significantly even if the vehicle is traveling on a poor road. Therefore, the routine proceeds to step 115, where the clamping pressure is low. Set to level. On the other hand, when the determination in step S116 is affirmative, the road surface condition is an unfavorable road condition even in the quasi-steady running condition, and the rotation fluctuation occurs to some extent. Therefore, the clamping pressure is set to the normal level based on the road surface condition (step S113).

Therefore, when the control shown in FIG. 3 is configured to be executed, it is possible to accurately control the clamping pressure according to the state of the road surface and to drive on a good road and in a quasi-steady state. In this case, the clamping pressure can be further reduced, so that the fuel efficiency is further improved.

Further, another control example executed by the control device of the present invention will be described. The control example shown in FIG. 5 is an example configured to remove the vibration component that becomes noise to improve the determination accuracy of the road surface state, and the rotation speed No on the output side No.
Is read (step S201) and its bandpass filter processing (step S202) is executed in the same manner as the control examples shown in FIGS. 1 and 3.

Then, it is judged whether or not the band-pass filtered values can be accumulated (integrated) (step S2).
03). If a negative determination is made in step S203 due to the inability to integrate, the process returns without performing any particular control. On the other hand, if the determination in step S203 is affirmative, the absolute value of the bandpass processed value is taken and the n pieces of data are integrated (step S2).
04). That is, time window integration is performed.

In order to remove the vibration component of the integrated value,
The annealing process is performed (step S205). this is,
One example is low-pass filter processing. Then, it is determined whether or not the integrated value Snout_lo (i) after the low-pass filter processing is larger than a predetermined value Snout1 that is predetermined as a reference value (step S206).

This step S206 is the step S11 shown in FIG. 1 and the step S114 shown in FIG.
This is a judgment step according to. Therefore, if the affirmative determination is made in step S206, it means that the vehicle is traveling on a poor road (bad road), and the bad road is determined. That is, the flag Fb is set to "1" (step S207). Next, the counter Cd for determining the end of the bad road is reset to zero, and then the process returns.

On the other hand, if the determination in step S206 is negative, it means that the vehicle is traveling on a good road. In this case, whether the bad road determination flag Fb is "1" or not. Is determined (step S209). That is, it is determined whether or not the immediately preceding road surface condition is a poor road. If the determination in step S209 is negative because the immediately preceding road surface condition is not a bad road but a good road, the process returns without performing any particular control.

On the contrary, if the affirmative determination is made in step S209 because the immediately preceding road surface condition is a poor road, the counter for determining the bad road end (bad road end counter). Cd is incremented (step S210). Then, it is determined whether or not the count value exceeds a predetermined value Cd0 (step S21).
1) If not exceeded, return. On the other hand, if the count value of the rough road end counter Cd exceeds the predetermined value Cd0 and a positive determination is made in step S211, the rough road end determination is made (step S2).
212). That is, the rough road end counter Cd and the rough road determination flag Fb are reset to zero. Therefore, the termination of the rough road is determined by the integrated value Snout_lo (i) after the low-pass filtering process becoming continuously larger than the predetermined value Snout1 a plurality of times.

When the determination of the rough road is established, the clamping pressure of the continuously variable transmission 1 is set to a high level, and when the determination of the rough road is not established or the end of the rough road is determined. The control of the clamping pressure, such as setting the clamping pressure to the normal level, may be executed in the same manner as the control example shown in FIG. 1 or the control example shown in FIG. In addition, each of the above predetermined values Snout1,
Cd0 may be a constant value, or may be a value that changes according to the running state of the vehicle such as acceleration / deceleration, accelerator opening, and vehicle speed.

Therefore, when the control shown in FIG. 5 is executed, the integrated value of the rotation speed on the output side that has been bandpass filtered is further smoothed (for example, lowpass filtering), and the result is obtained. Since the road surface condition is determined based on the obtained value, the road surface condition can be accurately determined. Since the clamping pressure of the continuously variable transmission 1 is controlled to be high or low based on this, slipping in the continuously variable transmission 1 can be effectively prevented, and excessive clamping pressure can be avoided to avoid fuel consumption. Can be improved.

In the present invention, instead of determining the road surface state based on the integrated value subjected to the bandpass filter processing or the value subjected to the smoothing processing described above, the integrated value or the smoothed processing value and the continuously variable transmission are used. The road surface state may be determined based on the rotational acceleration on the output side of the machine 1. For example, as shown in FIG. 6, first, the rotation speed N on the output side
The o is read (step S401), and the rotational acceleration ΔNo is calculated (step S402).

Then, the rotational acceleration ΔNo is a predetermined value α
It is determined whether or not this is the case (step S403). If the determination in step S403 is affirmative, for example, the drive wheel 20 temporarily idles by passing through a depression formed on the road surface, or the drive wheel 20 temporarily passes over a falling object or a protrusion. It is considered that the rotational acceleration .DELTA.No has increased due to, for example, idling, and therefore the rough road determination is established and the flag Fd is set to "0" (step S404). On the contrary, when the determination in step S403 is negative, it is determined that the rough road has ended,
The flag Fd is reset to zero (step S40).
5).

The flag Fd set in this way,
The clamping pressure may be positively controlled based on the rough road determination flag Fb used in the control example of FIG. Specifically, when both of the flags Fd and Fb are set to "1", the clamping pressure is set to a high level, and conversely, one of the flags Fd and Fb is set to "0". If it is set, the clamping pressure may be set to the normal level.

As described with reference to FIG. 3, in the present invention, the clamping pressure may be set lower than the normal level in the quasi-steady running state. A clutch such as the lock-up clutch 3 connected in series with 1 can function as a so-called torque fuse for the continuously variable transmission 1. This is because the excess amount (margin width) of the engagement pressure with respect to the minimum engagement pressure within the range where the clutch does not slip is determined by the clamping pressure against the minimum clamping pressure within the range where the continuously variable transmission 1 does not slip. When the torque is set to be smaller than the excess amount (margin width) of the pressure and the torque acting on the drive system increases, slippage occurs in the clutch before the continuously variable transmission 1 and further continuously variable. This is a function to prevent torque from acting on the transmission 1.

When the control for functioning the clutch as the torque fuse is also used, the increase in the engaging force of the clutch is delayed when the clamping pressure is increased as described above, and the increase in the clamping pressure is delayed. On the contrary, when the clamping pressure is reduced, the engagement pressure of the clutch is reduced first. This is to ensure the function of the clutch as a torque fuse even in a transient state.

The relationship between the above specific example and the present invention will be briefly described. The functional means of steps S2 and S202 described above correspond to the processing means of the present invention, and steps S4 and S204. The functional means of is equivalent to the integrating means of the present invention and corresponds to step S1.
The functional means of 1 and step S114 and step S206 correspond to the road surface condition determining means of the present invention. Further, the functional means of step S10, step S12, step S113, and step S115 correspond to the clamping pressure control means of the present invention. The functional means of step S205 corresponds to the smoothing means of the present invention.

It should be noted that the present invention is not limited to the above specific example, and the determination of the road surface condition may be performed by dividing it into three or more types in addition to the two types of determination of a good road and a poor road. Good. Further, the continuously variable transmission targeted by the present invention is not limited to the belt type, and may be a traction type. Further, in the above-described specific example, the example in which the bandpass filter process is performed as the filter process is shown, but in the present invention, instead of this, the highpass filter process may be performed. In that case, the filtered signal will contain high frequency components,
The road surface condition can be determined by such a signal.

[0077]

As described above, according to the first to third aspects of the present invention, the detected value of the wheel speed or the rotation speed corresponding thereto is filtered, and the filtered value is integrated or integrated. Since the road surface condition is determined based on the calculated value, even minute changes in the road surface can be determined as the road surface condition, and the road surface can be determined only by such minute fluctuations, so erroneous determination of the road surface condition can be avoided. Alternatively, it can be suppressed, and the road surface can be accurately determined as a whole. In other words, it is possible to accurately detect or determine the road surface condition by removing or suppressing the influence of noise.

Further, according to the invention of claim 4, since the vibration component contained in the time window integral value is removed by the smoothing processing, the smoothed time window integral value improves the road surface condition better. The value is reflected, and the accuracy of road surface condition determination can be improved.

On the other hand, according to the fifth aspect of the invention, since the minute rotational fluctuation is taken into the time window integral value subjected to the band pass filter, even a minute change in the road surface can be judged as the road surface condition, and Since the road surface is not judged only by such minute fluctuations, erroneous judgments can be avoided or suppressed, and the road surface condition can be accurately judged as a whole, and the clamping pressure of the continuously variable transmission can be applied to the road surface. It can be accurately performed based on the state, and eventually, the fuel consumption of the vehicle can be improved while preventing the continuously variable transmission from slipping.

Further, according to the invention of claim 6, when the good road judgment is made, the clamping pressure is reduced as compared with the case where the judgment is not made, so that the torque fluctuation due to so-called disturbance is possible. When the performance is low, it is possible to reduce the clamping pressure of the continuously variable transmission, improve the power transmission efficiency thereof, and improve the fuel efficiency of the vehicle.

Further, according to the invention of claim 7, since the vibration component included in the time window integral value is removed by the smoothing processing, the smoothed time window integral value improves the road surface condition better. As a result, the accuracy of road surface condition determination and clamping pressure control based on it is improved,
As a result, the continuously variable transmission can be prevented from slipping and the fuel efficiency of the vehicle can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a flowchart for explaining an example of detection and control of a road surface state by the device of the present invention.

FIG. 2 is a waveform diagram schematically showing a detected signal, a band-pass filtered signal and its absolute value, respectively.

FIG. 3 is a diagram showing a flowchart for explaining another example of road surface state detection and control by the device of the present invention.

FIG. 4 is a diagram for explaining regions of a steady traveling state and a quasi-steady traveling state in the control shown in FIG.

FIG. 5 is a diagram showing a flowchart for determining another road surface condition by the device according to the present invention.

FIG. 6 is a diagram showing an example of a flowchart for determining a road surface state based on the acceleration of the rotation speed on the output side.

FIG. 7 is a diagram schematically showing a drive system and a control system of a vehicle equipped with the continuously variable transmission according to the present invention.

[Explanation of symbols]

1 ... Continuously variable transmission, 3 ... Lock-up clutch, 5 ...
Engine (power source), 13 ... Drive pulley, 14 ... Followed pulley, 15, 16 ... Actuator, 17 ... Belt, 20 ... Drive wheel, 25 ... Transmission electronic control unit (CVT-ECU).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumi Hoshiya             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Yasuhiro Oshiumi             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3J552 MA07 MA09 MA12 MA26 NA01                       NB01 PA12 PA59 RB25 SA36                       VA32Z VA37W VB02W VC03Z                       VD02Z VD11Z VE03W VE05W

Claims (7)

[Claims] 1. A detection value of a rotation speed of a wheel or a rotation speed of a predetermined rotating member which rotates in a fixed relationship with the wheel is filtered, and a road surface state is detected based on the filtered value. A road surface state detecting device comprising: an integrating means for integrating the filtered values; and a road surface condition determining means for judging a road surface state based on the integrated value. 2. The road surface condition detecting device according to claim 1, wherein the integrating means includes means for performing time window integration of the filtered values. 3. The road surface condition determining means determines the road surface as a non-conforming road when the integrated value is equal to or more than a predetermined value set in advance, and determines the road surface is good when the integrated value is less than a predetermined value set in advance. 2. A means for determining a road is included.
Alternatively, the road surface state detection device according to item 2. 4. A smoothing processing means for smoothing the time window integral value is further provided, and the road surface state determining means is
The road surface state detection device according to claim 2 or 3, wherein the road surface state detection device is configured to determine a road surface state based on the time window integral value that has been subjected to the smoothing processing by the smoothing processing means. 5. A continuously variable transmission, the torque capacity of which changes according to the clamping pressure that clamps the torque transmitting member, is arranged between the power source and the drive wheels, and the output speed of the continuously variable transmission or the continuously variable transmission A controller for a continuously variable transmission, which controls the continuously variable transmission based on a change in the number of rotations of a rotating member including a drive wheel connected to an output side of the continuously variable transmission according to a road surface state, And a integrating means for integrating the value obtained by the filtering in a time window, and a road surface condition determining means for determining the road surface condition based on the time window integrated value. A control device for a continuously variable transmission characterized in that: 6. A clamping pressure control means for increasing the clamping pressure when the road surface condition judging means judges that the road surface condition is an unfavorable road as compared with the case where the road surface condition is judged as a good road. The control device for the continuously variable transmission according to claim 5. 7. The road surface condition determining means further comprises an anneal processing means for annealing the time window integral value.
7. The control device for a continuously variable transmission according to claim 5, wherein the road surface condition is determined based on the time window integral value that has been smoothed by the smoothing processing means. .