JPS6199747A - Creep torque control device of automatic speed change gear - Google Patents

Abstract

PURPOSE:To prevent creep and fall back on an ascent by controlling fastening force of friction element so that the creep torque becomes an objective creep torque balancing with a fall back torque according to the gradient of the road. CONSTITUTION:An automatic speed change gear 3 provided with a friction element 2 which transmits output rotation of a torque converter 1 has a road gradient sensor 4 detecting a road gradient, an objective creep torque setting means 5 setting an objective creep torque balancing with a fall back torque according to the road gradient, an actual creep torque detecting means 6 detecting an actual creep torque, and a fastening force control means 7 controlling fastening force of the friction element 2. The fastening force control means 7 controls fastening force of the friction element 2 so that the actual creep torque detected by the means 6 becomes the objective creep torque set by the means 5.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a device for controlling creep torque so that the creep torque of an automatic transmission can be used to keep a vehicle stopped on a road. There are 6 things.

(Prior Art) Since automatic transmissions are equipped with a torque converter in their power transmission system, they have different driving ranges, namely forward automatic transmission driving (D) range, cumulative 2-speed engine braking driving (1) range, or HjR1 range.
In these ranges, even if the friction element (usually the rear clutch) continues to operate regardless of the gear position, power can be transmitted.
The vehicle can be stopped as long as the engine is idling. However, the torque converter cannot reduce the transmitted torque to zero, and if the brake is left inactive, a so-called creep phenomenon will occur in which the vehicle moves forward at a slow speed in the above driving range.

In order to eliminate this creep phenomenon, a creep prevention device has been proposed that puts the frictional elements into a non-operating state, but on the other hand, the creep torque that causes this phenomenon is useful for keeping the vehicle stopped on the road. And it is actually IF!
A technique as shown in Japanese Patent Publication No. 108968/1983 has been proposed in the past. This technology prevents creep by keeping the friction elements inactive on roads other than uphill roads while stopped in the driving range, and completely connects the friction elements (stopping creep prevention) on uphill roads. The use of torque prevents the vehicle from moving backwards too quickly.

(Problem to be solved by the invention) However, with this technology, the creep torque always reaches the maximum value when creep prevention is stopped, and this does not necessarily match the reverse torque corresponding to the road slope, causing the vehicle to slow down to a very low speed. Move forward and protect yourself from creep.

(Means for Solving the Problems) In view of the above points, the first inventor of the present invention, as shown in FIG.
automatic transmission 8 equipped with a friction element 2 that transmits the output rotation of
, a road surface gradient sensor number for detecting the road surface gradient, a target creep torque setting means 5 for setting a target creep torque balanced with the backward torque according to the road surface gradient, and an actual creep torque detecting means 6 for detecting the actual creep torque. , the friction 11 [J! ! Fastening force control means 7 for controlling the second fastening force
It is made up of the following.

By the way, in the above configuration, under a steep road surface slope, there is a risk that the vehicle will still move backwards even if the creep torque reaches the maximum, and in such a case, it is preferable for safety to issue a warning to prompt the driver to apply the brakes.

From this point of view, the second invention of the present invention is as shown in FIG.
In an automatic transmission 8 that includes a friction element 2 that is continuously operated in a driving range and transmits the output rotation of a torque converter 1, a road slope sensor 4 that detects a road slope and a target that balances reverse torque according to the road slope are provided. A target creep torque setting means 5 for setting the creep torque, an actual creep torque detecting means 6 for detecting the actual creep torque, and a fastening mechanism for controlling the fastening force of the friction element 2 so that the 'iA creep torque becomes the target creep torque. It is provided with a force control means 7 and an alarm means 8 which issues an alarm at a steep slope where the target creep torque exceeds the limit value of the actual creep torque.

(Operation) In the first invention, the fastening force control means 7 controls the fastening force of the friction element 2 so that the actual creep torque detected by the means 6 becomes the target creep torque already set by the first means. Therefore, the actual creep torque corresponds to the reverse torque depending on the road surface slope, and it is possible to keep the vehicle stopped regardless of the road surface slope. enable.

In the @S invention, the first means 8 issues a warning on a steeply sloped road where the vehicle may retreat due to the above-mentioned action. Therefore, the driver can use this warning to predict when the vehicle will move backwards.
By operating the brake C, it is possible to avoid an unexpected situation in which the vehicle moves backward.

(Example) EMBODIMENT OF THE INVENTION Below, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 2 shows an embodiment of the present invention. In FIG. 1, 10 is a torque converter, and 11 is an automatic transmission (D).

1. I) A clutch as a SaW element that continues to operate hydraulically in the range; 12 is an engine. Torque converter 10
T! A pump impeller (input element) IOA driven by the crank 7-yaft ls & of the engine 13, a turbine launch (output element) IOB fluid-driven by this,
and a stake (reaction force l!cumulation) loc that increases the torque of the turbine runner by applying a reaction force to the electric fluid,
Turbine runner 10b is drivingly coupled to torque converter output shaft (input II of clutch 11) 1B. clutch 1
1 connects the time shaft 18 operated by the hydraulic pressure PoI/C to the clutch output shaft 14 to enable the automatic transmission to transmit power at the first gear position, and the automatic transmission is operated by this clutch operation and other friction elements. Other gear positions can be selected in combination with the operation of .

Clutch operating oil pressure P. is automatic transmission driving (D, I
1, I) The line pressure PL supplied to the circuit 15 only in the range is generated in the circuit 16 as the source pressure, and a pressure regulating valve 17 is inserted between the circuits 15 and 16 in order to control the operating oil pressure P0. Pressure regulating valve l? Is it school 1? a, and the upper end surface in the figure is U1? b, and the lower end surface is chamber 1? In addition to having C attend each, school le & spring l? At d, it is supported in the left half position in the figure.

Then, the chamber 171) is connected to the Ig circuit 15 by a branch 1311.
To.

Further, the chambers 170 are respectively connected to the circuit 16 by branch paths 19.
Drain hole 120 is installed in the middle of branch road 18.
do. Drain boat Z (Ic and Lenoid ikl are installed opposite each other, and this solenoid is always pristine. Plunger 11151 is located in the left half of the figure, and drain boat 420 is opened, and when energized, Granger Sla is in the left half of the figure. 20 will be closed. The solenoid S1 is driven at a constant frequency (for example, 60 Hz), and the average opening degree of the drain boat zo is controlled by changing the ratio of the driving time width to one cycle (duty). The control pressure becomes 0.

As the duty increases, the control pressure also increases, and the duty 1
At 00%, it is the highest value equivalent to line pressure PL.

When the control pressure is 0, the spool 17a is moved to the left half position in the figure by the spring 17d, connecting the circuit 15 to the drain boat Z8 and cutting it off from the circuit 16. As the control pressure rises, the spool 17a moves down in the figure to connect the circuit IS. While gradually increasing the communication with the circuit 16 (Drenbo)! Gradually reduce the communication with 1, and at the highest value of control pressure, the school l? 1L is in the right-hand position in the figure to cut off the circuit 15 from the drain boat 2B and to allow only the circuit 16 to communicate.Thus, since the control pressure changes depending on the duty, the working oil pressure P.f for this duty 9. The change characteristics are as shown in FIG.

The duty control of the solenoid 21 is controlled by the controller 3.
3, and this controller 9 is connected to a central processing unit (OFυ) 84 and a random access memory (RAM).
) 25, a read-only memory (ROM) s a, an input circuit 7 ace circuit 2 f, and an output interface circuit z8. And this controller z8 is the turbine runner 1
A signal from the turbine rotation sensor 29 that detects the rotation speed (torque converter output rotation speed) NT of 01) and a signal from the range switch 8u or 6 that is turned ON in the A road driving range.
)L and the throttle li+lI[Tfl of the engine Is
The signal from the throttle opening sensor 81 that detects the rotation speed Ng of the engine lz, the signal from the engine rotation sensor 3z that detects the rotation speed Ng of the engine lz, and the output rotation speed of the automatic transmission (KL luck)
The signal from the vehicle speed sensor 88 that detects V and the road surface slope θ
The signal from the road surface slope sensor 84 that detects It is assumed that the duty control of i11 is performed, and the control program shown in FIG. 4 is executed to perform duty control and ON/OFF control of the buzzer 86 as an alarm means.

The control program in FIG.
In the regular interrupt routine that is repeatedly executed every time o), first, in step 40, it is determined from the range signal whether the selected range of the automatic transmission is the travel (o, i, i) range in which creep torque control according to the present invention is to be performed. In the parking range other than these ranges, such as the parking range (P) range, the driving range (R) range, or the middle range L (N) range, another control program (not shown) is executed in step No. 1, and D. I or I
In the microwave, control is set to step command 3! ! happy clutch 11
The connection is controlled as follows.

In step 4z, it is determined whether the vehicle is running with the X speed V equal to or higher than the minute setting value v0 or is stopped without dripping v0.

If it is running, set duty D to 1004 in step 43.
After setting K, the duty is updated according to the step number. This duty 1004 causes the pressure regulating valve 1'F to set the working oil pressure P0 to the highest value corresponding to the line pressure PL8 as shown in FIG.
is fully tightened to allow normal driving of the vehicle. If it is determined in step 4s that the vehicle is stopped, in step 45 it is determined whether or not the throttle opening TH is fully closed and the vehicle is idling, that is, whether or not the stopped state is such that a start is not desired. If you want 146.
In step 47, the duty D is increased by α increments until it reaches 1 tl (1%), and the duty is updated in step 44.As a result of this increase in the duty D, the working oil pressure P is gradually increased as shown in FIG. It is possible to proceed with engagement of the clutch 11 and start the vehicle.In this start, since the duty D is increased step by step, the engagement of the clutch 11 is carried out slowly and the vehicle is started without any trouble.

If it is determined in step 46 that the vehicle is in a stopped state in which starting is not desired, the control proceeds to step 48t'C, and creep torque control according to the present invention is executed as follows. Step 48
Then engine speed (torque converter input speed) M
Et&! In the first step 49, the road surface slope θ is read. In the next step 60, the target slip amount (target creep torque) R of the torque converter IO is calculated based on the table data shown in the following table from the engine rotation aNE and the road surface gradient 0.
Table lookup for lj.

Rij's table data 'EI NlCs 'Es NK4 NIs 'Is
"ICj engine @ flf number CM, ) - 1 In setting this target slip amount R1,t-, the target creep torque determined by this slip amount is The target slip mRjJ is determined to be balanced with the torque. Therefore, the target slip mRjJ is determined based on the engine speed N.
Of course, if E (idling rotational speed) differs depending on whether or not the engine is being warmed up, it is necessary to correct the setting according to the C error.

In the next step IIl, the input/output rotation difference Ng -N of the torque converter 0 and the actual slip amount of the torque converter N-N, -NT (actual creep torque) are calculated, and in step 5m, the actual creep torque is calculated. It is determined whether or not the creep torque is equal to or greater than the target creep torque R11. 1M≧R1j
In this case, if the actual creep torque is higher than the target creep torque and the vehicle moves forward at a slow speed, step II+
8, the integral correction amount obtained by multiplying the K integral constant by 1 is subtracted from the previous duty D (OLD) to calculate the integral correction duty D (NEW), and in step 54, the current duty D is calculated. tD(NIW)-
It is determined by the calculation kp (nod R1j) (where is a proportionality constant), and this is updated in step 44. Thus, the duty D is the error (nod Rij), tc is the integral constant, and the proportionality constant is k.

As is clear from Figure 2, the actual creep torque can be lowered closer to the target creep torque by decreasing the pottery hydraulic pressure P0 (clutching force of the clutch 11). .

Conversely, if aN<Rlj, that is, if the actual creep torque is less than the target creep torque and the vehicle moves backwards, step 56.56 is followed by Step! 18° At No. 5, perform a calculation in the direction of increasing the duty, which is opposite to the commission, and perform calculation 9.
[Update D in step 44.

Thus, as is clear from FIG. 6, the actual creep torque can be increased so as to approach the target creep torque by increasing the working oil pressure P0 (clutch 1Lf).

Due to the above, l! The creep torque is maintained at the target creep torque, and the creep phenomenon can be prevented regardless of the road surface gradient θ, and the vehicle can be prevented from moving backward on the uphill road.

Figure 4 shows another example of the control program. In this example, step 6 is added between steps 5 ors 1, and in the next step, the target slip amount R1j exceeds the engine rotation speed MIC, which is the limit value of the actual creep torque. whether or not
In other words, when Kura Tsuchi 11 is fully engaged, the torque converter Zoo stall state 1 is set to the rotation speed NTt-O of s13.
1()N = My;, -NT-N,)K also gives (
R greater leap torque t (Therefore, it is determined whether the road surface slope is too steep to prevent the horse from retreating. If Rij≦NE, the control proceeds to step 51, and the example described above is performed using the same action. Prevents creep and backtracking, but -R
If lj>-, the brake signal B(
(See Figure 3) to determine whether or not the brake is being applied. Then, while the brake is in operation, the creep torque is maximized by completely engaging the clutch 11 with the duty D t-100 at 6t'LVi step 48, and if the brake is not in operation, the buzzer 86 (see Fig. 3) goes to step 69. ) by operating
] It is possible to issue a driver IC warning that the vehicle is in a situation where the vehicle is moving backwards on a steep slope.

By the way, a step device? Then, the same effect can be obtained even if the target slip amount R1j is compared with a set value other than the engine rotational speed N, which is slightly smaller than MIc.

In this case, it is possible to issue a warning before the road surface inclination reaches its maximum limit.
In the illustrated example, the target creep torque (
In the illustrated example, since the configuration is such that the engagement force (operating oil pressure P0) of the friction element (clutch 11 in the illustrated example) is controlled so that the torque converter target slip lid Ri is reached, the vehicle can be controlled with creep torque according to the road surface gradient θ. This allows the vehicle to be stopped, and it is possible to reliably prevent creep and backtracking on any boarding road.

Further, in the second invention, on a steep uphill road where the vehicle moves backward due to the above action, l! (buzzer 86)
Since the 1iF111 is configured to operate the brake, it is possible to predict the backward movement of the vehicle, and by operating the brake, it is possible to prevent the vehicle from moving backward unexpectedly.

(*Effect of Example) In addition, as shown in Figure 8.4, the target creep torque (
In the case where the torque converter input rotation U (Rlj) is also changed by the engine rotation NErc, even if this rotation speed is different before and after warming up the engine, the above-mentioned effects of the present invention can be reliably achieved. be able to.

[Brief explanation of the drawing]

Figure 1 (al and b+ are respectively conceptual diagrams of the apparatus of the present invention. Figure 2 is a 7-stem diagram showing an embodiment of the apparatus of the present invention. Figures 3 and 4 are controllers in the apparatus of the present invention, respectively. Flowcharts showing two examples of control programs executed by the controller. Fig. 5 is a characteristic diagram of changes in clutch operating oil pressure with respect to duty. 1.10...Torque converter 2...Friction element 3...Homemade transmission number , 8
4... Road surface gradient sensor 5... Zero league torque setting means 6... Actual creep torque detection means 7... Fastening force control means 8... Alarm means 11...
・Clutch (friction element) tS...Engine 18...Torque converter tb force s 14...Clutch output shaft 15...Twin pressure supply (b) path Ill...Clutch operating hydraulic circuit 17... Pressure regulating valve 18.19... Branch road go, ss... Dorenbo) 21... Runoid 2
B... Controller 29... Turbine rotation sensor 80... Range switch ill... Throttle opening sensor 8z... Engine rotation sensor 3B... Vehicle speed sensor 3'6... Brake switch 86...・Buzzer (11 notification means) Patent applicant Nissan Motor Co., Ltd. Figure 1 (a)

Claims (1)

[Scope of Claims] 1. In an automatic transmission equipped with a friction element that continues to operate in a driving range and transmits the output rotation of a torque converter, the automatic transmission includes a road gradient sensor that detects a road gradient, and a reverse torque according to the road gradient. a target creep torque setting means for setting a target creep torque balanced with the target creep torque; an actual creep torque detecting means for detecting the actual creep torque; and a fastening force for controlling the fastening force of the friction element so that the actual creep torque becomes the target creep torque. 1. A creep torque control device for an automatic transmission, comprising a control means. 2. The creep torque control device for an automatic transmission according to claim 1, wherein the target creep torque setting means sets the target creep torque from the input rotational speed of the predetermined torque converter and the road surface gradient. 3. In an automatic transmission equipped with a friction element that continues to operate in the driving range and transmits the output rotation of the torque converter, there is a road slope sensor that detects the road slope, and a target creep torque that balances the reverse torque according to the road slope. target creep torque setting means for setting the actual creep torque; actual creep torque detecting means for detecting the actual creep torque; fastening force control means for controlling the fastening force of the friction element so that the actual creep torque becomes the target creep torque; 1. A creep torque control device for an automatic transmission, comprising a warning means for issuing a warning at a steep road slope where the torque exceeds the limit value of the actual creep torque.