JPH0213185B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a method for controlling a creep prevention device for a vehicle with an automatic transmission.

(2) Conventional technology When a vehicle equipped with an automatic transmission sets the gear shift lever to the drive position (forward position) while the vehicle is stopped, the drag torque of the torque converter causes
This shows a so-called creep phenomenon in which the car tries to move forward against the driver's will. Because of this phenomenon, the driver had to keep pressing the brake pedal with some force while stopped, and it also affected the engine.
It is necessary to widen the idling opening of the throttle valve by an amount corresponding to this dragging torque, which is undesirable because it worsens fuel efficiency.

Conventionally, as a device to prevent this creep phenomenon, a discharge oil passage leading to an oil tank is branched from a supply oil passage that supplies hydraulic pressure to the starting clutch of an automatic transmission, and the discharge oil passage is closed in a demagnetized state and energized. A device equipped with a solenoid valve that opens when the

(3) Problems to be Solved by the Invention In the conventional device described above, the solenoid valve is energized only when the vehicle is stopped, and the hydraulic pressure supplied to the starting clutch is released to the discharge oil path, thereby shutting off the starting clutch. However, in order to put this into practical use, it is desired that the following problems be solved.

That is, when starting, the creep prevention device is deactivated and the starting clutch, which had been in a disconnected state, is reconnected.
Since a large driving torque from the engine is suddenly applied to the stopped wheels, some type of shock is likely to occur. In order to reconnect this smoothly, it is possible to use a pressure increasing valve or an accumulator, but in that case, the structure would be large and complicated, and the oil path would also be complicated, leading to high costs. .

The present invention has been developed in view of the above-mentioned problems, and has made it possible to smoothly shift the starting device to a fully activated state with an extremely simple operation, in the same way as when using a pressure increasing valve or the like. An object of the present invention is to provide a method for controlling a creep prevention device for a vehicle with an automatic transmission.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a method for discharging oil that is connected to an oil tank from a supply oil path that supplies working hydraulic pressure to a starting clutch of an automatic transmission. In a creep prevention device for a vehicle equipped with an automatic transmission, the creep prevention device is provided with a solenoid valve that branches a discharge oil passage in a demagnetized state and opens it in an energized state. When the electromagnetic valve is held in an energized state when the number and vehicle speed are lower than predetermined values and the brake pedal is depressed, and when the energized state is switched to the demagnetized state by releasing the brake pedal, the starting clutch is smoothly operated. The solenoid valve is repeatedly energized and de-energized in small increments within a predetermined time so that the solenoid valve transitions to a fully connected state, and during the repetition, the length of each demagnetization time is increased as time passes, and furthermore, the solenoid valve is energized and de-energized. The present invention is characterized in that the solenoid valve is switched to a demagnetized state when the accelerator pedal is depressed even during repeated excitation.

(2) Action When releasing the brake pedal to return the solenoid valve from the energized state to the demagnetized state in order to deactivate the creep prevention device in the activated state, the solenoid valve is opened and closed in small increments, and each closing time is can be increased over time to allow a very smooth gradual increase in the operating hydraulic pressure of the starting clutch, resulting in a transition to a fully engaged state of the starting clutch, i.e., a large drive torque from the engine to the stopped wheels. The transmission of information is carried out extremely smoothly without any shock. In particular, by deactivating the creep prevention device by releasing the brake pedal, the starting clutch is activated immediately when the driver simply releases his/her foot from the brake pedal, that is, sooner than when the driver depresses the accelerator pedal. Since the transition to the fully connected state is started, the creep prevention device can be quickly deactivated in response to the driving operation. Further, even when the brake pedal is depressed, the creep prevention device does not operate when the engine speed or vehicle speed is higher than a predetermined value, so that an engine braking effect can be effectively obtained.

Furthermore, even if the solenoid valve is repeating the energization and de-energization, if the accelerator pedal is suddenly depressed, the solenoid valve is switched to the demagnetized state, so the creep prevention device can be returned to the inactive state immediately. can.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. The signal is sequentially transmitted to the driving wheels W, W' and drives them.

The torque converter T includes a pump impeller 2 connected to a crankshaft 1, a turbine impeller 3 connected to an input shaft 5 of an auxiliary transmission M, and a stator 4 disposed between both impellers 2 and 3. configured. The torque transmitted from the crankshaft 1 to the pump impeller 2 is hydrodynamically transmitted to the turbine impeller 3, and when the torque is amplified during this time, the stator 4 bears the reaction force as is known. . A pump drive shaft 7 for driving the hydraulic pump P shown in FIG. 2 is provided at the right end of the pump impeller 2.

The input and output shafts 5 of the auxiliary transmission M are parallel to each other.
A first speed gear train, a second speed gear train, and a third speed gear train are provided in parallel between the six gears. The first speed gear train includes a drive gear 8 connected to the input shaft 5 via a first speed or starting clutch _C1 , and a drive gear 8 connected to the output shaft 6 via a one-way clutch _C0 . The 2nd speed gear train is composed of a driving gear 10 connected to the input shaft 5 via a 2nd speed clutch _C2 , and a driven gear 9 connected to the output shaft 6 and meshing with the driving gear 10. The 3rd speed gear train consists of a driven gear 11 that meshes with the input shaft 5, and a driven gear 11 that is connected to the output shaft 6 via a 3rd speed clutch _C3 . It is composed of a driven gear 13 that meshes with the driven gear 13.

Therefore, if only the first gear clutch _C1 is connected,
The drive gear 8 is connected to the input shaft 5 to establish a first speed gear train, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train. Next, while 1st gear clutch C ₁ remains connected, 2nd gear clutch C ₂ is connected.
When connected, the drive gear 10 is connected to the input shaft 5 to establish a second-speed gear train, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train.
During this time, the output shaft 6 rotates at a higher speed than the driven gear 9 of the 1st gear train due to the difference in gear ratio between the 1st and 2nd gear trains, so the one-way clutch is closed.
C ₀ idles and virtually stops the first gear train.
In addition, when the first gear clutch C ₁ is connected,
If the second speed clutch _C2 is disconnected and the third speed clutch _C3 is connected, the driven gear 13 is connected to the output shaft 6.
A third-speed gear train is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train. In this case as well, the one-way clutch C ₀ idles to bring the first gear train to rest, similar to when the second gear train is established. The torque transmitted to the output shaft 6 is
A differential gear is connected to the output gear 14 provided at the end of the shaft 6.
It is transmitted to the large diameter gear 15 of Df. Note that the reverse gear train and the parking device are omitted in FIG. 1 for the sake of simplification of explanation.

In FIG. 2, when the hydraulic pump P is driven by the pump drive shaft 7, it pumps the oil in the oil tank Ot to the speed change control device Cc. The transmission control device Cc receives the vehicle speed signal a and the throttle valve opening signal b representing the magnitude of the output of the engine E, and controls the discharge of the hydraulic pump P every time the value of these signals exceeds a predetermined reference value. The hydraulic pressure is applied to the clutches C ₁ , C 2 , C ₃ for 1st, _2nd , and 3rd speeds.
It is now being selectively supplied to Then,
Each clutch is connected by being supplied with hydraulic pressure to establish a corresponding gear train as described above.
The speed change control device Cc may be of any type, such as a fully hydraulic type or an electric/hydraulic type using a solenoid valve or the like. Further, the discharge pressure of the hydraulic pump P itself may be made variable in response to the torque conversion ratio signal c of the torque converter T.

A creep prevention device Nc is provided between the first speed, that is, the starting clutch _C1 and the speed change control device Cc. This device Nc includes an orifice 17 provided in a supply oil path 16 connecting the speed change control device Cc and the hydraulic chamber of the starting clutch _C1 , and a discharge oil path 18 that branches from the downstream side of the orifice 17 and reaches an oil tank Ot. It is constructed by interposing a pilot type control valve V.

The control valve V has a spool valve 19 that connects the discharge oil passage 18 to an upstream portion 18 that is connected to the supply oil passage 16.
a and a downstream part 18b connected to the oil tank Ot, and is accommodated in a cylindrical valve chamber 20 formed in the middle part thereof, and oil chambers 21 and 22 are defined at the upper and lower parts of the valve 19. . Its upper oil chamber 21
is a return spring 2 that springs the spool valve 19 downward.
3 is accommodated. This spool valve 19 has a pair of upper and lower lands 19a and 19b, an annular groove 19c sandwiched between these lands, and an annular groove 19c that connects this groove 19c to an upper oil chamber 2.
1 and the lower oil chamber 22, the annular groove 19c is always in communication with the upstream part 18a, and the upper land 19a has an opening port to the valve chamber 20 in the downstream part 18b by its vertical movement. 26 can be opened and closed. port 26
is preferably formed to have a circular cross-sectional shape so that its effective opening area gradually increases as the upper land 19a moves upward. An end wall member 28 having an orifice 27 is provided at the upper end of the valve chamber 20, and an electromagnetic valve 29 having a pilot needle valve 30 for opening and closing the orifice 27 is further provided above the end wall member 28. The needle valve 30 is adapted to close the orifice 27 under the force of a spring 31 and open it when the solenoid 32 is energized, and also to open the orifice 27 when the solenoid 32 is energized.
7 communicates with a bypass oil passage 33 branched from the downstream portion 18b of the discharge oil passage 18 when opened.

Therefore, the speed change control device Cc operates the starting clutch _C1.
When hydraulic pressure is being supplied to the supply oil passage 16 to connect the solenoid valve 29 to the orifice 27
When the upper oil chamber 21 is opened, the upper oil chamber 21 becomes approximately atmospheric pressure, so the hydraulic oil that has passed through the orifice 17 of the supply oil path 16 is transferred to the upstream portion 18a of the discharge oil path 18, the annular groove 19c, the orifice 24, and the upper oil chamber 21. , the orifice 27, the bypass oil passage 33, and the downstream portion 18b, and are discharged to the oil tank Ot. At this time, since the lower oil chamber 22 is filled with the hydraulic oil that has flowed from the annular groove 19c through the orifice 25,
A differential pressure is generated between the upper and lower oil chambers 21 and 22, which exerts an upward force on the spool valve 19. As a result, the spool valve 19 moves upward against the force of the return spring 23, and the upper land 19a moves upward to the port 26. to open. Therefore, the discharge oil passage 18 becomes completely conductive, and the pressure oil that has passed through the orifice 17 is discharged to the discharge oil passage 18 with almost no resistance, so that the starting clutch _C1 is cut off, and the creep phenomenon of the vehicle is prevented. suppressed. During this time, the supply oil line 16 is
An orifice 17 limits the flow of pressure oil to a certain level.

When the solenoid valve 29 is demagnetized and the orifice 27 is closed, the flow of oil from the annular groove 19c to the upper oil chamber 21 is stopped, and the differential pressure between the upper oil chamber 21 and the lower oil chamber 22 is reduced. 2, the spool valve 19 tries to move downward by the force of the return spring 23. As the spool valve 19 moves downward, the volume of the lower oil chamber 22 decreases.
Since the volume of the upper oil chamber 21 communicating through the orifice 25, the annular groove 19c, and the orifice 24 increases by the volume reduction of the lower oil chamber 22, there is a risk that the hydraulic oil may be trapped in the lower oil chamber 22. Without this, the spool valve 19 can gradually move downward while pushing out a part of the hydraulic oil in the lower oil chamber 22 toward the upper oil chamber 21 side. Thus, by the downward movement of the spool valve 19, the upper land 19a closes the port 26 and shuts off the discharge oil passage 18, so that all the hydraulic pressure supplied from the transmission control device Cc to the supply oil passage 16 is used for starting. It is introduced into the hydraulic chamber of clutch _C1 and connects it, making it possible to start.

In this case, if the drain oil path 18 is rapidly shut off,
As already mentioned, the oil pressure in the hydraulic chamber of the starting clutch _C1 suddenly increases, causing a sudden creep phenomenon, which causes a shock in the vehicle.In order to alleviate this shock, the present invention has developed a solenoid valve. 29
The excitation and demagnetization are repeated in small steps a predetermined number of times n within a predetermined time, and during the repetition, the length of each demagnetization time is increased with the passage of time.
In this way, the pilot needle valve 30 repeats opening and closing by the number n of repetitions of excitation and demagnetization of the electromagnetic valve 29, and the length of closing time becomes longer as time passes, so that the amount of oil passing through the orifice 27 increases. The spool valve 19 gradually decreases very smoothly, the spool valve 19 moves quietly, and the discharge oil path 18 is gradually shut off. As a result, the pressure in the hydraulic chamber of the starting clutch _C1 gradually increases very smoothly, so that the reconnection of the clutch _C1 is smooth and shock-free.

An example of an electric circuit for controlling the energization of the solenoid valve 29 is shown in FIG. In the same figure, the vehicle speed detection device 34 rotates a magnet rotor 35 in conjunction with the wheels, and generates a pulse signal from a reed switch 36 that connects and disconnects contacts by this rotation.The signal is transmitted via an interface circuit 37. The pulses are input to the microcomputer 38, where the vehicle speed is calculated from the period of the input pulses.

The accelerator operation detection device 39 has a normally open switch 4 that closes only when the accelerator pedal 40 is depressed.
1, and a signal generated by closing this switch 41 is input to the microcomputer 38 via the interface circuit 42.

The brake operation detection device 43 includes a normally open switch 4 that closes only when a brake pedal 44 is depressed.
5, and a signal generated when this switch 45 is closed is also input to the microcomputer 38 via an interface circuit 46.

The engine rotation speed detection device 47 extracts an ignition pulse signal from between the engine's ignition coil 48 and the igniter 49. This signal is also input to the microcomputer 38 via the interface circuit 50, where the period of the input pulse is Engine speed is calculated.

The engine temperature detection device 51 has a normally open switch 52 that closes only when the engine cooling water temperature rises above a certain value, and the signal generated when this switch 52 closes is also transmitted via the interface circuit 53. and input into the microcomputer 38.

The drive position detection device 54 includes a gear shift lever 55
The microcomputer 38 has a normally open switch 56 that closes only when the motor is set to the drive position (forward position), and a signal generated when the switch 56 closes is also input to the microcomputer 38 via an interface circuit 57.

The microcomputer 38 has a built-in program based on the flowchart shown in FIG. 4, processes input signals from the various detection devices, and sends signals to the drive circuit 58 in accordance with the program. The drive circuit 58 operates to close the energizing circuit 59 of the electromagnetic valve 29 when the input signal is, for example, at a high level, and opens the circuit when the input signal is at a low level.

As is clear from the flowchart in Figure 4,
The solenoid valve 29 is energized, i.e. the anti-creep device
Nc is activated when the gear shift lever 55 is set to the drive position, the engine temperature has risen above the predetermined value _T1 , the engine speed has fallen below the predetermined value _N1 , and the accelerator pedal 40 is activated. is released and the vehicle speed is below the predetermined value _V1 ,
This is also when the brake pedal 44 is being depressed.

When the brake pedal 44 is released while the creep prevention device Nc is in operation, the magnetization and demagnetization of the solenoid valve 29 are repeated in small steps a predetermined number of times within a predetermined time, and when this is confirmed, the solenoid valve 29 is held in the demagnetized state. The anti-creep device Nc therefore returns to its inoperative state. A time chart of small repetitions of energization and demagnetization of the solenoid valve 29 is shown in FIG.

Further, if the accelerator pedal 40 is suddenly depressed while the solenoid valve 29 is repeatedly energized and demagnetized in small steps as the brake pedal 44 is released, the solenoid valve 29 is energized and demagnetized in small steps. It stops repeating and is immediately demagnetized. Therefore,
The anti-creep device Nc can immediately return to the inoperative state. This means that starting clutch C ₁
This prevents the engine speed from rising due to a connection delay, and allows the vehicle to start smoothly.

As described above, according to the present invention, the discharge oil passage leading to the oil tank is branched from the supply oil passage that supplies hydraulic pressure to the starting clutch of the automatic transmission, and the discharge oil passage is closed in a demagnetized state and in an energized state. In a creep prevention device for a vehicle with an automatic transmission, which is provided with a solenoid valve that opens at The solenoid valve is energized and de-energized so that when the solenoid valve is held in an energized state and the energized state is switched to a de-energized state by releasing the brake pedal, the starting clutch smoothly transitions to a fully connected state. is repeated in small increments within a predetermined period of time, and the length of each degaussing time is increased over time, so in order to deactivate the creep prevention device that is in operation, the brake pedal is released and the solenoid valve is activated. When returning from the energized state to the demagnetized state, the solenoid valve is opened and closed in small increments, and each closing time is increased as time passes,
The operating hydraulic pressure of the starting clutch can be increased very smoothly and the transition to the fully engaged state of the starting clutch, i.e., the transmission of large drive torque from the engine to the stopped wheels, can be carried out without shock. This can be done extremely smoothly and can greatly contribute to improving riding comfort. Moreover, in order to repeatedly open and close the solenoid valve in small steps as described above, it is only necessary to make slight modifications to the conventional electric circuit of the solenoid valve, so there is no need to make the structure larger or the oil path complicated. It is very advantageous in terms of cost. In particular, by deactivating the creep prevention device by releasing the brake pedal, the starting clutch is activated immediately when the driver simply releases his/her foot from the brake pedal, that is, sooner than when the driver depresses the accelerator pedal. Since the transition to the fully connected state is started, the creep prevention device can be quickly deactivated in accordance with the driving operation, and the automobile can be started quickly. Furthermore, even if the brake pedal is depressed, the creep prevention device will not operate if the engine speed or vehicle speed is higher than a predetermined value.
Although the depression of the brake pedal is one of the operating conditions for the creep prevention device, there is no risk that the engine braking effect will be lost due to the operation of the creep prevention device.

Furthermore, even if the solenoid valve is in the process of repeating the energization and de-excitation, if the accelerator pedal is suddenly depressed, the solenoid valve is switched to the demagnetized state, thereby preventing creep when the accelerator pedal is suddenly depressed. The device can be returned to the inoperative state immediately, and the phenomenon of engine rotational speed rising due to a delay in engagement of the starting clutch can be prevented, and the vehicle can be started more smoothly.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the power system of a vehicle with an automatic transmission to which the method of the present invention is applied, Fig. 2 is a hydraulic circuit diagram including a creep prevention device of the automatic transmission, and Fig. 3 is an electrical control diagram of the creep prevention device. The circuit diagram, FIG. 4 is a flowchart for controlling the solenoid valve of the creep prevention device, and FIG. 5 is a time chart showing the timing of excitation and demagnetization of the solenoid valve. Cc...speed change control device, E...engine, M...
…Auxiliary transmission, Nc…Creep prevention device, Ot…
...Oil tank, P...Hydraulic pump, T...Torque converter, V...Control valve, 1...Crankshaft, 2
...Pump impeller, 3...Turbine impeller, 4...
... Stator, 16 ... Supply oil path, 18 ... Discharge oil path, 19 ... Spool valve, 29 ... Solenoid valve, 30
...Pilot needle valve, 32...Solenoid, 34
... Vehicle speed detection device, 38 ... Microcomputer, 43 ... Brake operation detection device, 47 ... Engine rotation speed detection device, 54 ... Drive position detection device, 58 ... Drive circuit, 59 ... Current supply circuit.

Claims (1)

[Claims] 1. A discharge oil passage 18 leading to an oil tank is branched from a supply oil passage 16 that supplies hydraulic pressure to a starting clutch C ₁ of an automatic transmission, and this discharge oil passage 18 is closed in a demagnetized state and opened in an energized state. Solenoid valve 2
In the creep prevention device for a vehicle with an automatic transmission, the creep prevention device is provided with the above-mentioned creep prevention device for a vehicle with an automatic transmission, which is provided with The solenoid valve 29 is kept in an energized state, and when the energized state is switched to a demagnetized state by releasing the brake pedal 44, the solenoid valve 29 is energized and de-energized so that the starting clutch _C1 smoothly transitions to a fully connected state. is repeated in small increments within a predetermined period of time, and during the repetition, the length of each demagnetization time is increased over time, and even when the solenoid valve 29 is in the process of repeating the energization and de-energization, the accelerator pedal 40 is not depressed. 1. A method for controlling a creep prevention device for a vehicle equipped with an automatic transmission, characterized in that a solenoid valve 29 is switched to a demagnetized state when the solenoid valve 29 is in a demagnetized state.