JPH0369023B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a control system for an automatic transmission used in an automobile, and is particularly intended to control driving force when the vehicle turns. [Prior Art] Conventionally, various types of automatic transmissions have been provided that automate the complicated gear change operations that humans perform with their hands and feet. The gear change of the above automatic transmission is automatically performed based on the vehicle speed and the amount of accelerator depression.When the amount of accelerator depression is large, the automatic transmission determines that there is a "sudden acceleration" and changes the driven shaft and drive shaft. The automatic transmission will downshift to the gear with the stronger acceleration force to change the rotation ratio between the gear and the gear, and when the accelerator is released and the amount of depression is small, the automatic transmission will judge that there is no need to accelerate, and the acceleration force will be weaker. It is designed to upshift to the higher gear. By the way, in such an automatic transmission, since the above-mentioned gear change is executed even when the vehicle turns, there is a problem in that running stability deteriorates on sharp curves. In other words, when trying to pass a corner safely and quickly, a driver should decelerate sufficiently in a straight line before the corner to a speed suitable for the corner, based on the slow-in-fast-out principle, and then accelerate inside the corner. In order to get out of the corner quickly, the driver increases the amount of accelerator pedal depression, but in order to accelerate inside the corner, the automatic transmission automatically downshifts to the gear with the stronger acceleration force, and the driving force increases rapidly. I will do it. Therefore, if excessive driving force is applied during a turn, the limit of cornering force required for stable driving will be lowered, leading to a decrease in the cornering power of the drive tire, and furthermore, the inner wheel load will be reduced during a turn, resulting in a decrease in driving stability. becomes lacking. Therefore, as a solution to these problems,
An automatic transmission, as shown in Japanese Patent Publication No. 48-9729, which detects the rotation angle of the steering wheel and prohibits gear changes when making sharp curves, has already been proposed. [Problems to be Solved by the Invention] However, the above-mentioned conventional vehicles having automatic transmissions also have the following problems and are still not satisfactory. In other words, if the rotation angle of the steering wheel is detected and the gear change of the automatic transmission is prohibited whenever the vehicle makes a sharp turn, the gear change will be prohibited even when accelerating in a low throttle opening range where the change in driving force is relatively small. However, there were problems in that the necessary driving force could not be obtained and driving stability during cornering was impaired. The present invention has been made in view of the above problems, and
It is an object of the present invention to provide a control device for an automatic transmission that always has excellent running stability during sharp cornering where the turning angle is greater than a predetermined value. [Means for solving the problems] The configuration of the present invention for solving the above problems is as follows:
As shown in the block diagram of Fig. 1, driving state detection means M detects the driving state of the vehicle.
1, a transmission means M2 for switching the gear ratio of an automatic transmission that transmits the output of the internal combustion engine to the drive wheels, and a transmission means M2 for changing the transmission ratio of an automatic transmission that transmits the output of the internal combustion engine to the drive wheels, and a transmission means M2 for driving the transmission means M1 based on the operating state detected by the operating state detecting means M1. A control device for an automatic transmission having a shift command means M3 for giving a command, an acceleration degree detection means M4 for detecting the degree of acceleration of the vehicle, and a turning degree detection means M for detecting the degree of turning of the vehicle.
5, a turning degree change rate calculating means M for calculating a change rate of the turning degree of the vehicle from the detected turning degree of the vehicle;
6, when the detected degree of acceleration of the vehicle is equal to or greater than a predetermined value, and the detected degree of turning of the vehicle is equal to or greater than a predetermined value, the shift command means M3 instructs the shift means M2 to downshift; The gear shift inhibiting means M7 prohibits the shift down command when the detected degree of turning of the vehicle and the rate of change in the degree of turn calculated are each smaller than a predetermined value, and the detected degree of acceleration of the vehicle prohibits a downshift command. The gist thereof is a control device for an automatic transmission, characterized in that it is equipped with a shift inhibition canceling means M8 for canceling the prohibition of the above-mentioned downshift command when the degree of acceleration of the vehicle has increased from the current degree of acceleration of the vehicle. . The driving state detecting means M1 detects the vehicle speed, throttle opening, etc. while the vehicle is being driven, and detects factors that are the basic gear selection of the automatic transmission. To detect the vehicle speed, a wheel sensor that detects the rotational speed of the wheel is used, and to detect the throttle opening, an accelerator pedal sensor that detects the amount of operation of the accelerator pedal and a throttle installed in the intake passage are used. A throttle valve opening sensor or the like is used to detect the opening of the throttle valve. The transmission means M2 changes the transmission ratio of an automatic transmission that transmits the output of the internal combustion engine to the drive wheels, and controls the driving force and speed of the vehicle by changing gears. The speed change command means M3 gives a command to the speed change means M2 so that the speed change means M2 changes speed,
Based on the information from the operating state detection means M1, a command is given to operate at the optimum gear ratio at the time of the operation.
The speed change command means M3 may be one that uses hydraulic pressure, or one that operates a control valve electrically. The acceleration degree detection means M4 is for detecting the degree of acceleration of the vehicle, and the following devices are used. (1) Something that detects the amount of accelerator pedal depression. (2) Something that detects the throttle valve opening. (3) Something that detects the rate of change in wheel rotation speed over a certain period of time. (4) Something that detects the displacement difference between the front wheel suspension and the rear wheel suspension. (5) Detects inertial force (acceleration) when a vehicle accelerates. The turning degree detecting means M5 detects how much the vehicle has turned, and the following means or the like is used. (1) A device that detects the amount of rotation of the steering wheel by the driver. (2) When a vehicle turns, the rotational speeds of the left and right wheels are different, so the difference in rotational speed between the left and right wheels is used for detection. (3) When a vehicle turns, the vehicle body rolls, so this is detected by the difference in displacement between the left and right suspensions. (4) Detects the lateral inertia of the vehicle when it turns. The turning degree change rate calculating means M6 calculates the time change rate of the turning degree of the vehicle, that is, the turning speed of the vehicle, from the turning degree of the vehicle detected by the turning degree detecting means M5. The shift inhibiting means M7 has a function of determining whether a sudden change in drive torque due to a downshift or spin of the wheels associated with it occurs, and a function of preventing the automatic transmission from downshifting when this occurrence is anticipated. It also has a shift prohibition function that holds the shift. The former function determines whether the degree of acceleration of the vehicle detected by the acceleration degree detection means M4 is above a predetermined value, and whether the degree of turning of the vehicle detected by the turning degree detection means M5 is above a predetermined value. If both conditions are met, it is determined that a sudden change in drive torque due to downshifting or spin of the wheels associated with it has occurred. The above-mentioned shift prohibition function prohibits the above-mentioned shift command means M3 from issuing a downshift signal to be outputted to the shift means M2, or prevents the shift-down signal from being outputted to the shift means M2 even if such a shift signal is input to the shift means M2. This is to issue a shift prohibition command signal so as not to execute the shift. The shift inhibition release means M8 has both a shift inhibition release function of releasing the shift down hold of the automatic transmission, and a function of determining whether or not to activate the shift inhibition release function. What is the judgment function?
Whether the degree of turning detected by the turning degree detection means M5 is smaller than a predetermined value (condition 1), and whether the rate of change in the degree of turning calculated by the turning degree change rate calculating means M6 is smaller than a predetermined value (condition 2). ,
Further, it is determined whether the degree of acceleration of the vehicle detected by the acceleration degree detection means M4 has increased from the degree of acceleration of the vehicle at the time when the shift down command was prohibited by the shift prohibition means M7 (condition 3); When all of the above three conditions are met, the shift prohibition release function is activated. Note that each of the above predetermined values is an arbitrary value and has no relation to each other. Further, the degree of acceleration of the vehicle used for determining condition 3 may be determined based on the amount of depression of the accelerator pedal, so that it is possible to clearly recognize whether the driver has an intention to increase the speed. The above-mentioned speed change prohibition release function is the above-mentioned command means M3.
Then, a shift prohibition release command signal is issued to cancel the shift prohibition command signal issued from the shift prohibition means M7, thereby canceling the prohibition of the shift down command. [Function] The control device for the automatic transmission having the above-mentioned configuration is configured such that the turning state detected by the turning state detection means M4 is a sharp turn of a predetermined degree or more, and the degree of acceleration detected by the acceleration degree detection means M5 is a sudden acceleration of a predetermined degree or more. In this case, in order to prevent the transmission means M3 from automatically downshifting in response to a command from the transmission command means M4, the transmission prohibition means M7 prohibits the transmission command means M3 from giving the above-mentioned command. This prevents sudden excessive driving force from occurring. Therefore, the limit of cornering force for stable running is not lowered and the wheel spin is prevented from occurring. Also, after the gear shift inhibiting means M6 is activated and the acceleration turn is made,
When turning is to be slowed down, instead of downshifting immediately when the degree of turning becomes small, downshifting is performed only when there is a certain degree of acceleration and the intention is to increase the degree of acceleration. Therefore, after a turn, the driver simply eases up on the degree of turning and continues to press the accelerator as he did during the turn, so there is no need to downshift, and the driver is not caught off guard and does not feel uncomfortable. It's working. Also, when driving on an S-shaped course, the downshift hold will work once when turning, then the downshift will work while the steering wheel is turned back and the driver is turning in the opposite direction, and if the driver continues to turn, the downshift will work again. It works so that the driver does not feel any discomfort or discomfort because the system does not hold up. In addition, if the amount of depression of the accelerator pedal is detected in order to detect whether the degree of acceleration is increased, it will be possible to more reliably recognize whether the driver has an intention to increase the speed. This prevents the driver from downshifting unexpectedly. EXAMPLES Hereinafter, in order to explain the present invention more specifically, the present invention will be described in detail by giving examples. [Example] A first example of the present invention will be described based on FIGS. 2 to 7. FIG. 2 is a schematic configuration diagram showing the overall configuration of the first embodiment of the present invention. The present embodiment will be explained using a vehicle with a rear wheel drive electronically controlled automatic transmission as an example. 1
is the transmission body, 2 is the hydraulic control unit, 3 is the vehicle speed sensor, 4 is the throttle sensor, 5 is the steering angle sensor,
5a represents a shift position switch, and 6 represents an electronic control section. The transmission 1 includes a torque converter 7 and a planetary gear mechanism 8 with three forward speeds and one reverse speed. The torque converter 7 includes a pump impeller 9, a turbine impeller 10,
A well-known type composed of a stator 11,
The pump impeller 9 is connected to an engine crankshaft 12 , and the turbine impeller 10 is connected to a turbine shaft 13 to input rotational force to the planetary gear mechanism 8 . The planetary gear mechanism 8 includes two multi-slope clutch devices engaged by a hydraulic servo mechanism, two hydraulic brake band devices, a one-way clutch using a sprag,
It consists of a planetary gear train consisting of a sun gear and a pinion gear. Incidentally, FIG. 3 shows a sectional view of a main part of the planetary gear mechanism, and the explanation will be continued based on FIGS. 2 and 3. The turbine shaft 13 is connected by a front clutch 14 to an intermediate shaft 1 with an input sun gear 15.
6 and is also connected to a reverse sun gear 18 by a rear clutch 17. A brake band device (hereinafter referred to as front brake band 19) for braking the reverse sun gear 18 is provided on the outer periphery of the rear clutch 17 and is operated by a hydraulic servo. The input sun gear 15 meshes with gears 21 of pinion gears 20 arranged in an appropriate number (for example, two or three sets) on the circumference.
The reverse sun gear 18 meshes with an idler gear 23 on the carrier 22, and the gear 24 of the pinion gear 20 mentioned above meshes with the idler gear 23. A gear 25 at the rearmost end of the pinion gear 20 meshes with a gear 27 on an output shaft 26 of the transmission.
The pinion gear 20 and idler gear 23 are supported on a carrier 22 by pinion pins 28 and 29, and a brake band (hereinafter referred to as rear brake band 30) is attached to the carrier 22 for braking.
It is operated by a hydraulic servo. The carrier 22 further includes a one-way clutch 31, which fixes the carrier 22 in one direction of rotation. Next, the operating state of the transmission obtained by the above configuration will be described. In the first gear, the front clutch 14 and rear brake band 30 are applied (however, if the engine is driven from the engine side, the one-way clutch 31 is also activated, so it is not necessary to apply the rear brake band 30, but in this case, the output shaft 26 (The rotation of the turbine shaft 13 is transmitted to the input sun gear 15. Since the carrier 22 is fixed by the rear brake band 30, the pinion pin 28 is also fixed, and the input rotation is transmitted from the input sun gear 15.) gear 21 and gear 2
5, the signal is decelerated and transmitted to the gear 27 on the output shaft. In the second speed, the front clutch 14 and front brake band 19 are activated. Input is made from the input sun gear 15, and the reverse sun gear 18 is in a stationary state because the rear clutch 17 is fixed by the front brake band 19. The rotation of the input sun gear 15 causes the carrier 22 to rotate in the same direction as the input sun gear 15 due to the reaction force of the reverse sun gear 18, thereby transmitting the reduced rotation to the gear 27 of the output shaft 26. Third speed is obtained by operating the front clutch 14 and rear clutch 17. Input is input sun gear 15 and reverse sun gear 1
8, the entire planetary gear system rotates as one, and the turbine shaft 13 and output shaft 26 drive one-to-one. Reverse movement is achieved by applying the rear clutch 17 and rear brake band 30. The pinion pins 29 and 28 are fixed according to the carrier 22, and the input from the turbine shaft 13 is transmitted to the reverse sun gear 18,
Idler gear 23, gear 24 of pinion gear 20
and 25 to the gear 27 of the output shaft 26, so that the output shaft 26 is reversed. Next, the hydraulic control unit 2 changes from 1st speed to 2nd speed and from 2nd speed to 1st speed.
1-2 shift solenoid and 2
2- is responsible for the operation from speed to 3rd speed and from 3rd speed to 2nd speed.
It is composed of a well-known hydraulic control circuit including three shift solenoids, and mainly uses hydraulic pressure from the oil pump to adjust the hydraulic pressure of the operating lines of the front clutch 14, rear clutch 17, front brake band 19, rear brake band 30, etc. Just make the switch. Here, the energization state of the two shift solenoids and the operating state of the front clutch 14, rear clutch 17, front brake band 19, rear brake band 30, and one-way clutch 31 are compared to the operating position of the shift position switch 45a and the driving gear position. The relationship is shown in Table 1.

[Table] In Table 1, ON and OFF are states in which the solenoid is energized and de-energized, respectively, / indicates that the gear position is selected regardless of whether the solenoid is energized or de-energized, and ○ indicates that the hydraulic servo is activated. In the L position and first speed state, the one-way clutch operates when power is transmitted from the engine to the output shaft of the transmission, that is, when the engine is driven. The shift position switch 5a indicates the position of the shift lever and sets four drive states: neutral, reverse, forward, and first stage forward, and are generally referred to as N, R, D, and L positions, respectively. . The vehicle speed sensor 3 is a well-known power-generating rotation sensor that uses a permanent magnet with a coil wound around it to obtain an alternating current voltage with a frequency proportional to the vehicle speed. The throttle sensor 4 is a well-known sensor that outputs a signal voltage responsive to the opening degree of the throttle valve. The steering angle sensor 5 detects the steering angle of the steering wheel, and is installed in the steering gear box 101, as shown in the explanatory diagram of FIG. It is configured to detect In FIG. 4, 102 represents a steering wheel, and 103 represents a steering column. The steering angle sensor 104 can also detect the steering angle based on the amount of rotation of the steering wheel operated by the driver.
The amount of rotation of the steering shaft mounted on the steering column 103 and held on the steering column 103 may be detected by a photoelectric conversion method, an electromagnetic pickup method, a contact method, or the like. Next, FIG. 5 shows a block diagram of the electronic control section 6 and its related parts. 201 inputs and calculates data output from each sensor such as the vehicle speed sensor 3, throttle sensor 4, steering angle sensor 5, and shift position switch 5a according to a control program, and also controls the operation of various devices. 202 is a read-only memory (hereinafter simply referred to as ROM) in which control programs and initial data are stored; 203 is a central processing unit (hereinafter simply referred to as ROM) that performs the processing of data and calculations input to the electronic control unit 6; A random access memory (hereinafter simply referred to as RAM) in which data necessary for control is temporarily read and written, 204 is an input port (not shown), a waveform shaping circuit provided as necessary, and a CPU 201 that outputs the output signals of each sensor.
An input section 205 is equipped with a multiplexer that selectively outputs a signal, an A/D converter that converts an analog signal into a digital signal, etc., and an output port 205 is provided, as well as a 1-2 shift solenoid 2 as required.
06 or 2-3 shift solenoid 207, respectively. The automatic transmission control processing by the electronic control unit 6 of the automatic transmission control system of this embodiment configured as described above will be explained in detail with reference to the flowcharts of FIGS. 6 and 7. This routine is performed when the shift position switch 5a is in the D range.
This is a CPU control process, and when the shift position switch 5a is in another range, it is not shown as it is well known. The flowchart of FIG. 6 showing the automatic transmission's shift prohibition process will now be explained. Note that this routine is processed by interrupting the CPU 201 at predetermined intervals when the vehicle is driving. When the processing of this routine starts, step 300 is executed first. In step 300, the initial settings of this routine are performed, and at least a, which will be described later, is cleared to zero. In the following step 301, the vehicle speed V is detected by the vehicle speed sensor 3. In the following step 302, the degree of turning of the vehicle is detected from the output of the steering angle sensor 5, and the steering angle H1 is detected. In the following step 303, the degree of acceleration of the vehicle is detected from the output of the throttle sensor 4, and the throttle opening degree S1 is detected. Processing then moves to step 304;
Then, the steering angle H1 detected in step 302 above is
Determine whether it is 90° or more. step 304
If it is determined that the steering angle H1 is 90 degrees or more, the process moves to step 305. In step 305,
Throttle opening degree S1 detected in step 303 above
Determine whether it is more than 1/2 of the fully open state.
If it is determined in step 405 that the throttle opening degree S1 is 1/2 or more, the process continues to step 306.
At step 06, bit a is set to 1. This "a" serves as a flag indicating whether or not to execute a routine representing the next shift prohibition cancellation process, and will be described in detail later. Next, the process goes to step 307.
In step 307, the throttle opening degree detected in step 302 is set to θ1. When the process of step 307 is completed, the process of this routine ends. Note that if it is determined in step 304 that the steering angle H1 is smaller than 90 degrees, the process proceeds to step 304.
Continue to 308, and in step 305 throttle opening S
The process also continues to step 308 if it is determined that 1 is smaller than half the opening of the fully open state. step 308
Now, a shift position that can provide a more optimal speed and driving force is calculated based on the vehicle speed V detected in step 301 and the throttle opening S1 detected in step 303. Processing then moves to step 309,
In step 309, the 1-2 shift solenoid 206 or 2-3 shift solenoid 207 is activated so that the gear can be shifted to the shift position calculated in step 308.
Sends a signal that drives the energized state. Then, the processing of this routine ends. That is, the speed change prohibition means M6 is executed by skipping the processing of steps 308 and 309. When the CPU 201 completes the automatic transmission shift prohibition process shown in the flowchart of FIG. 6, the automatic transmission shift prohibition release process shown in the flowchart of FIG. 7 is subsequently executed. When the processing of this routine is started, the processing of step 310 is executed first. In step 310, it is determined whether a is 1 or not. A takes the value 1 in step 306 of FIG. 6, and serves as a flag indicating whether or not the process of the shift inhibiting means M6 has been executed. If a is determined to be 1 in step 310, the process moves to step 311 to execute the processes from step 311 of this routine. on the other hand,
If a is determined to be other than 1, no processing is performed and the processing of this routine is ended. When the process moves to step 311, in step 311,
Throttle opening degree S2 is detected by the same process as step 303 in FIG. In the following step 312, the sixth
The steering angle H2 is detected by the same process as step 302 in the figure. In the following step 313, the time rate of change H2 of the steering angle H2 detected in step 312 is calculated. Processing then moves to step 314;
Then, it is determined whether the throttle opening degree S2 detected in step 311 is 1/2 or more of the fully open state. In step 314, throttle opening S2 is 1/2
If it is determined that the value is smaller, the processing of this routine ends. Note that if it is determined in step 314 that the throttle opening degree S2 is 1/2 or more, the process continues to step 315. In step 315, the above steps
It is determined whether the steering angle H2 detected in step 312 is smaller than 90° and the time rate of change H2 of the steering angle calculated in step 313 is smaller than 45°/second.
In step 315, H2 is 90° or more or/and H2 is
If it is determined that the speed is 45°/sec or more, the process returns to step 311 and the routine after step 311 is repeated. If it is determined in step 315 that H2 is less than 90 degrees and H2 is less than 45 degrees per second, the process proceeds to step 316. step
In step 316, it is determined whether the throttle opening degree S2 detected in step 311 is greater than θ1 set in step 307 of FIG. 6 above. step
If it is determined in step 316 that the throttle opening degree S2 is less than or equal to θ1, the process returns to step 311 and the routine after step 311 is repeated. If it is determined in step 316 that the throttle opening degree S2 is greater than θ1, the processing of this routine is terminated. As described above in detail, the automatic transmission control device of this embodiment executes the shift prohibition process shown in FIG. If it is larger than 1/2, a hold is performed so that shift change processing is not performed. Then, by executing the process shown in the flowchart of FIG. 7 after the above-mentioned hold is performed, (1) when the throttle opening S2 falls below 1/2, or (2) when the steering angle H2 becomes 90 The time change rate H2 of the steering angle falls below 45°/sec.
In addition, when the acceleration of the vehicle has increased from the time when the downshift command was prohibited, the hold is released. On the other hand, if the above conditions are not met, the downshift hold is maintained by repeating the processes from step 311 to step 316. Therefore, even if the accelerator pedal is greatly depressed during a sharp turn, an excessive driving force is not applied and the limit of cornering force is not lowered, allowing stable driving. Furthermore,
Even when the steering wheel is loosened after a turn, excessive driving force is not generated even if the accelerator is depressed to a certain extent, so the driver does not feel uncomfortable and can drive stably even on S-shaped courses. It also has excellent effects. Next, a second embodiment of the present invention will be described based on FIGS. 8 to 11. FIG. 8 is a schematic configuration diagram showing the overall configuration of a second embodiment of the present invention, in which a road surface humidity sensor 401 is further provided in the system configuration of the first embodiment. The road surface humidity sensor 401 uses various detection devices or a combination thereof, such as whether the road surface on which the vehicle is running is paved or whether a water film is formed on the road surface. This is to detect whether or not it is in a slippery condition. More specifically, as shown in the explanatory diagram of FIG. 9, it is composed of a light emitting section 402 that includes a light emitting diode therein, and a light receiving section 403 that is provided in advance at a position where the light emitted from the light emitting section reaches when specularly reflected. It is something that With such a configuration, when the light emitting diode emits light of a specific wavelength in response to the light emission signal given to the light emitting unit 402, the light emitted from the road surface 40
The more the surface of the light receiving section 40 exhibits characteristics close to a mirror surface, the more the light receiving section 40 becomes
The amount of light reaching the condenser lens 405 of No. 3 increases, and the output signal from the photoelectric conversion element 406 increases. Therefore, if the road surface 404 is in a state where a water film is generated due to rain or the like, the output W of the road surface humidity sensor becomes large, and the mirror surface condition of the road surface and the output of the light receiving section 403 are almost proportional to each other. Yes, it is possible to detect the condition of the road surface. Note that the electronic control unit and its related parts in this embodiment are almost the same as in the first embodiment, and can be referred to in FIG. , throttle sensor 4,
Not only the signals from the steering angle sensor 5 and the steering angle sensor 5 are input, but also the signal from the road surface humidity sensor 401 is input. The automatic transmission control processing by the electronic control unit of the automatic transmission control system of the second embodiment configured as described above will be explained in detail with reference to the flowchart shown in FIG. Note that, like the first embodiment, this embodiment is a CPU control process when the shift position switch 5a is in the D range, and when the shift position switch 5a is in other ranges, it is shown as a well-known process. do not have. This routine also represents the process of prohibiting the automatic transmission from changing gears, and is interrupted by the CPU at predetermined intervals when the vehicle is being driven. When the processing of this routine starts, step 500 is executed first. The steps of this routine
500-503, steps 504-505, steps 506-509
The processing is carried out from step 300 of the first embodiment, respectively.
303, steps 304 to 305, and steps 306 to 309, so the explanation will be omitted. Following step 500, processing proceeds to step 501, step 502, step 503, and then processing continues to step 500.
Move to 503a. In step 503a, the current road surface condition is detected from the output of the road surface humidity sensor 401. In other words, the light receiving section 40 of the road surface humidity sensor 401
The output W of 6 is detected. Next, the judgment processing in step 504, and step 505.
The judgment process in step 505a is executed. In step 505a, it is determined whether there is a possibility that the wheels will spin based on the vehicle speed V detected in step 501 and the road surface humidity W detected in step 503a. In reality, as shown in the map showing the area where the wheels spin in Fig. 11, when the vehicle speed V and road surface humidity W are constant, it is possible to determine the boundary line 601 where the wheels spin based on the steering angle and throttle opening. When the steering angle is larger than the boundary line 601 and/or the throttle opening is large, the vehicle speed V and road surface humidity W are displayed in the area corresponding to the shaded area 602 on the upper right side of the boundary line 601.
It is determined that there is a possibility that the wheels may spin when the indicated point determined by The boundary line varies depending on the vehicle speed V and the road surface humidity W, and as shown by a straight line 603, the higher the vehicle speed V and the higher the road surface humidity W, that is, the more water there is on the road surface, the closer it gets to the origin. If it is determined in this step that there is a possibility of wheel spin, the process continues to steps 506 and 507, and the process of this routine ends. On the other hand, if the steering angle becomes 90 degrees or less in step 504, or if the throttle opening S becomes less than 1/2 of the fully open state in step 505, or if it is determined that there is no possibility of wheel spin in step 505a. If so, processing continues at step 508. After step 508 is executed, the process then moves to step 509 and ends the processing of this routine. In the CPU, when the automatic transmission shift prohibition process shown in the flowchart of FIG. 10 is completed, the automatic transmission shift prohibition release process is subsequently executed. This shift inhibition canceling process is the same as that shown in FIG. 7 of the first embodiment, and the explanation thereof will be omitted. As explained above, when the steering angle of the automatic transmission according to the second embodiment is larger than 90 degrees and the amount of operation of the throttle opening is larger than 1/2 of the throttle opening when the throttle is fully opened, The possibility of wheel spin is detected depending on the road surface humidity W, and no shift change is performed for cases where wheel spin is likely to occur. Therefore, the first
In addition to having excellent effects similar to those of the embodiment, this embodiment detects the possibility of wheel spin depending on the vehicle speed V and road surface humidity W, so even if the vehicle speed is higher than normal driving, This embodiment also has an excellent effect that the vehicle can turn and accelerate with almost no anxiety even when the road surface is wet due to rain. In the first embodiment, the predetermined value for determining the throttle opening in the shift prohibition process is set to 1/2 (step 305 in FIG. 6), and the predetermined value for determining the throttle opening in the shift prohibition canceling process is set to 1/2 (step 305 in FIG. 6). is set to 1/2 (step 314 in Figure 7), but
There is no relationship between these predetermined values, and the predetermined values may be different as appropriate. The same holds true for the steering angle, and in step 304 of Fig. 6.
The angle of 90° has no relationship with the 90° in step 315 of FIG. 7, and may be set to a different predetermined value as appropriate.
Incidentally, this is the same not only in the first embodiment but also in the second embodiment. Furthermore, although both the first and second embodiments use a steering angle sensor that detects the steering angle of the steering wheel as a means for detecting the degree of turning, any sensor that detects the degree of turning of the vehicle may be used. Alternatively, the left and right driven wheels may be provided with left and right driven wheel sensors for detecting the rotational speed, and the degree of turning may be detected based on the difference in rotational speed between the left and right driven wheels. Also, when the vehicle tries to turn, the vehicle body rolls, so this rolling state can be detected, for example, by a vehicle height sensor that detects the distance between the suspension arm and the vehicle body, or by a sensor that detects the torsion angle of the stabilizer. You may also do so. Alternatively, a gyrometer or the like may be used to detect the inertia force in the yaw direction of the vehicle that occurs when the vehicle turns. Furthermore, although a throttle sensor is used as the means for detecting the degree of acceleration, an accelerator pedal operation amount sensor that detects the amount of operation of the accelerator pedal may be used, and a wheel sensor that detects the rotational speed of the wheel may be used to detect the amount of wheel rotation. The rate of change in rotational speed over a certain period of time may be detected, and the displacement difference between the front wheel suspension and the rear wheel suspension may be detected using a vehicle height sensor that detects the distance between the suspension arm and the vehicle body. You may also do so. Further, the inertia force when the vehicle accelerates may be detected by an accelerometer or the like. That is, the present invention is not limited to the first and second embodiments described above, and can be implemented in various forms without departing from the gist of both embodiments. [Effects] As described in detail above, the present invention prevents downshifts from being performed even if the acceleration exceeds a predetermined value during a sharp turn where the degree of the turn is greater than a predetermined degree, thereby preventing excessive downshifts during the turn. This prevents the generation of driving force. Therefore, the current gears can sufficiently secure the minimum driving force necessary for acceleration while preventing the occurrence of wheel spin when turning, and it is possible to turn safely and quickly. Incidentally, recent large-capacity, high-horsepower engines are particularly effective because they tend to generate excessive driving force when turning. Furthermore, even after exiting a corner, instead of immediately downshifting when the degree of turning becomes small, the hold on downshifting is released only when there is a certain amount of acceleration and you want to increase the acceleration. This prevents excessive driving force from being generated after turning. This prevents the occurrence of sudden downshifts that cause discomfort to the driver after turning, allowing comfortable and stable driving. In particular, it is possible to prevent the occurrence of downshifts even when the steering wheel is turned back and the vehicle is turning in the opposite direction when driving on an S-shaped course, contributing to stable driving on the S-shaped course.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIGS. 2 to 7 show a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram showing the overall configuration of this embodiment, FIG. 3 is a sectional view of main parts of the planetary gear mechanism, FIG. 4 is an explanatory diagram explaining the steering angle sensor, and FIG. 5 is an electronic control unit 6. and its related parts; FIG. 6 is a flowchart showing the process of prohibiting the shift of the automatic transmission of this embodiment; FIG. 7 is a flowchart of the process of canceling the prohibition of shifting of the automatic transmission of this embodiment; 8 to 11 show a second embodiment of the present invention, FIG. 8 is a schematic configuration diagram showing the overall configuration of this embodiment, FIG. 9 is an explanatory diagram illustrating the road surface humidity sensor, and FIG. The figure is a flowchart showing the shift prohibition process of the automatic transmission of this embodiment, and FIG. 11 is a map showing the area where the wheels spin. M1...driving state detection means, M2...speed change means, M3...speed change command means, M4...acceleration degree detection means, M5...turning degree detection means, M6...turning degree change rate calculation means, M7... Gear change prohibition means,
M8...Transmission prohibition release means, 1...Transmission body,
2... Hydraulic control unit, 3... Vehicle speed sensor, 4... Throttle sensor, 5... Steering angle sensor, 5a...
Shift position switch, 6...Electronic control section,
7...torque converter, 8...planetary gear mechanism,
14...Front clutch, 17...Rear clutch, 19...Rear brake band, 30...Front brake band, 201...CPU, 202
...ROM, 203...RAM, 204...input section, 205...output section, 206...1-2 shift solenoid, 207...2-3 shift solenoid, 401...road surface humidity sensor.

Claims (1)

[Scope of Claims] 1. A driving state detection means for detecting the driving state of the vehicle; a transmission means for switching the gear ratio of an automatic transmission that transmits the output of the internal combustion engine to the driving wheels; and a driving state detected by the driving state detection means. A control device for an automatic transmission having a shift command means for issuing a shift command to drive the transmission means based on a driving state, comprising an acceleration degree detection means for detecting the degree of acceleration of the vehicle, and an acceleration degree detection means for detecting the degree of turning of the vehicle. a turning degree detecting means for detecting a turning degree; a turning degree change rate calculating means for calculating a change rate in the turning degree of the vehicle from the detected turning degree of the vehicle; a shift prohibiting means for prohibiting the shift command means from instructing the shift means to downshift when the detected degree of turning of the vehicle is equal to or greater than a predetermined value; If the rate of change is smaller than a predetermined value, and the detected degree of acceleration of the vehicle is greater than the degree of acceleration of the vehicle at the time when the downshift command was prohibited, the downshift command is prohibited. A control device for an automatic transmission, comprising: means for canceling a shift inhibition. 2. Claim 1, wherein the acceleration degree detection means detects the throttle opening degree as the degree of acceleration of the vehicle.
A control device for an automatic transmission as described in .