JPH05196124A - Automatic transmission - Google Patents

Abstract

PURPOSE:To correctly judge whether the input torque is positive or negative, i.e., a power-on travel or a coasting travel, contributing to the speed change control of an automatic transmission. CONSTITUTION:Rotation sensors 60, 61 are provided at the front and rear of a torque converter 30 connected to a torque transmission path including planetary gear sets 10, 11. The rotation sensors 60, 61 detect the torque converter input/output rotating speeds. When the input rotating speed is higher than the output rotating speed, the travel is judged as a power-on travel. When the input rotating speed is lower, the travel is judged as a coasting travel, and an automatic transmission switches the torque transmission path for a speed change with the logic corresponding to the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement in hydraulic control during upshifting of an automatic transmission.

[0002]

2. Description of the Related Art FIG. 1 shows a forward two-speed transmission using one planetary gear set. 1 is an input shaft, 2 is an output shaft, 3 is a planetary gear set, and the planetary gear set 3 is a sun gear 3S, a ring gear 3R, a carrier 3C,
It is composed of a pinion gear 3P, and the input / output shafts 1 and 2 are connected to a sun gear 3S and a carrier 3C, respectively. Also, 4
Is a band brake, 5 is a transmission case,
The band brake 4 fixes and releases the ring gear 3R to the case 5. A hydraulic clutch 6 engages and disengages the input shaft 1 and the ring gear 3R.

The relationship of the rotational speed ω of each rotary element of the planetary gear set is as follows:

## EQU1 ## αω _S + βω _C + ω _R = 0. However, the subscripts S, C, and R of ω are the same as the subscripts of the respective elements of the planetary gear set 3, and α,
β is a value determined by the number of gear teeth, and the ring gear 3
When the numbers of teeth of R and sun gear 3S are Z _R and Z _S , respectively,

## EQU2 ## α = Z _s / Z _R and β = − (1 + α). Further, the rotational speeds ω _i and ω ₀ of the input / output shafts 1 and 2 are
of course

## EQU3 ## ω _i = ω _S and ω ₀ = ω _C.

This transmission is rewound by a band brake 4.
When the ring gear 3R is fixed to the case 5 and stops, the gear
Ratio G_LBecomes -β / α> 1.0, and the clutch 6
When the ring gear 3R is connected to the input shaft 1 by the
Ratio G_HBecomes 1.0. Also, the inertial mass of each rotating part
Is the inertial mass of the input rotating part including the sun gear 3S, _i,
The inertial mass of the rotating part including the ring gear 3R is I_R, Carry
A) The inertial mass of the output rotating part including 3C is I₀And However
However, the inertial mass of the pinion gear 3P is ignored. Input shaft 1
The input torque applied to is T_i, Output transmitted from the output shaft to the wheels
Force torque is T ₀The transmission torque of the band brake 4 is represented by
Ku is T_SB, The transmission torque of the clutch 6 is T_CLExpress with.

Next, the behavior of the transmission in each state will be described. Hereinafter, for simplicity, (d / dt) ω ₀ = 0. At the low gear position, T _SB is the reaction force from Case 5, which is uniquely determined by T _i .

Equation 4] _{T SB = [(- β /} α) -1] T i = (1 / α) T i However, a T _CL = 0. Also, at high gear position, T _CL is

[Equation 5] T _CL = (− 1 / β) T _i T _SB = 0.

During shifting, (1) the state where the band brake 4 is engaged and the clutch 6 is slipping, (2) the state where the band brake 4 is slipping and the clutch 6 is engaged, and (3) both are slipping. The output torque T ₀ , the rotational speed change speed (d / dt) ω _{i of} the input shaft 1, the band brake reaction force T _SB or the clutch transmission force T _CL are as shown in the table of FIG.

Here, the case of upshifting from the low speed gear position to the high speed gear position will be described. The band brake reaction force T _SB before the shift is (1 / α) T _i , and the clutch transmission force T _CL after the shift is − (1 / β) T _i . At this time, the clutch 6 is slip-engaged while the band brake 4 is still engaged, and the band brake 4 is slid and released at a certain position [change from state (1) to state (3)].
On the contrary, the method in which the band brake 4 is slid and then the clutch 6 is engaged while slidingly coupling [from the state of (3)
Change to the state of (2)].

These states will be considered for upshifting during power-on traveling, that is, when T _i > 0. In the former method, as the hydraulic pressure P _{CL of the} clutch 6 is increased, the output torque T ₀ decreases and the reaction force T _SB of the band brake 4 also decreases. When the hydraulic pressure _PSB of the band brake 4 is drained to 0 near _TSB = 0, the rotational change of the input shaft 1 starts. At this time, (d / dt) ω _i <0, and the input rotation decreases. By the way, generally, since the input shaft 1 is engaged with a component having a large inertial mass such as a torque converter, the output torque T ₀ increases. Then, the torque value corresponding to the high-speed gear position is reached when the shift is completed. On the other hand, in the latter method, the hydraulic pressure P _SB of the band brake 4 is relatively higher than the oil pressure P _CL of the clutch 6, (d / dt)
Since ω _i > 0, the engine runs idle and the output torque T ₀ decreases. Therefore, in general, in upshift shifting,
It is usual to control like the former. The behavior at this time is shown in FIG.

Next, let us consider an upshift gear shift during inertial running where T _i <0. In the former method, the band brake reaction force T _SB and the output torque T ₀ decrease as the hydraulic pressure of the clutch 6 increases, similar to the upshift transmission during the power-on traveling. Then, band brake 4
Since the reaction force T _SB of the band brake is originally negative, the same logic as during power-on traveling, that is, T _SB = 0, the band brake 4 is applied.
The logic of setting the hydraulic pressure _PSB of 0 to 0 cannot be used. Meanwhile, in the latter method, by pulling relatively pressure P _SB of the band brake 4 to the hydraulic P _CL of the clutch 6, the _{(d / dt) ω i <} 0. When the input shaft rotational speed ω _i reaches the rotational speed corresponding to the high speed gear position, the clutch 6 can be engaged to reduce the shock as compared with the former case. The behavior at this time is shown in FIG. It should be noted that FIG. 4 shows an example of the case where control is performed by the former method during coasting.

[0010]

However, in the conventional automatic transmission represented by the above, for example, in 1984,
As shown in the electronically controlled 4-speed automatic transmission described on page 104 of Mitsubishi Heavy Industries Technical Report Vol. 21 No. 1, issued monthly, it is necessary to judge whether the vehicle is powered on or coasted depending on the engine throttle opening. However, as described in the technical report, there is a problem that the above determination cannot be performed correctly when there is an auxiliary machine drive load, a change over time, or a road surface inclination. The present invention is
By comparing the input and output speeds of the fluid transmission connected to the torque transmission path to determine whether the input torque to the torque transmission path is positive or negative, it is possible to determine whether the power-on traveling or coasting is performed. The object of the present invention is to make the determination accurately so as to solve the above problem.

[0011]

To this end, an automatic transmission according to the present invention has a hydraulic power transmission device, and multi-stage gear shifting is achieved by switching a torque transmission path connected to this device by a torque transmission path switching element. In the automatic transmission that realizes a ratio and is capable of arbitrarily controlling the transmission torque of the torque transmission path switching element, an input rotation speed detection unit that detects an input rotation speed to the fluid transmission device, and an automatic transmission from the fluid transmission device. Output rotation speed detection means for detecting the output rotation speed, and the positive / negative of the torque input to the torque transmission path by judging the magnitude of the input rotation speed and the output rotation speed from the signals from these input / output rotation speed detection means. And a positive / negative torque discriminating means for discriminating between the positive / negative torque discriminating means for discriminating the hydraulic pressure supply / discharge control logic for the torque transmission path switching element at the time of shifting. Those configured to switch in response to positive and negative input torque to torque transmission path.

[0012]

In the automatic transmission, the torque transmission path is switched by the torque transmission path switching element to shift to each gear, and the hydraulic pressure supply / discharge control logic for the torque transmission path switching element at the time of shifting is determined. The positive / negative of the input torque to the torque transmission path used for the above is determined as follows.
That is, the input and output rotational speeds of the fluid transmission connected to the torque transmission path are detected by the input rotational speed detection means and the output rotational speed detection means, respectively, and based on these detection results, the positive and negative torque determination means determines the input and output rotational speeds. The magnitude is judged, and the positive / negative of the torque to the torque transmission path is judged from this judgment result. Therefore, it is possible to accurately determine whether the torque is positive or negative without being affected by disturbance, as compared with the conventional method that is determined from the engine load such as the engine throttle opening degree. The determination can be accurate, and the determination of the hydraulic pressure supply / discharge logic based on the determination can be made more appropriate.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. 5 to 9 are views showing an embodiment of the present invention, which is an automatic transmission having four forward gears and one reverse gear. First, the structure of the torque transmission path will be described.
Is an input shaft and an output shaft, and 5 is a transmission case. 10 and 11 are planetary gear sets, which are the sun gears 10S and 11S and the carrier 10 respectively.
C, 11C, ring gears 10R, 11R, and pinion gears 10P, 11P, and 10 is called a front planetary gear set and 11 is called a rear planetary gear set. 1
Reference numerals 2 to 16 are friction engagement elements as torque transmission path switching elements, respectively, 12 is a low clutch, 13 is a low & reverse brake, 14 is a band brake, 15 is a high clutch, and 16 is a reverse clutch. These fastening elements are selectively fastened by a hydraulic control valve which will be described later, and a combination of fastenings (marked with a circle) shown in FIG. 5 realizes _four forward stages (D _{1 to} D ₄ ) and one reverse stage (R). To do.

Reference numeral 30 denotes a torque converter as a fluid transmission device, which includes a pump impeller 30P and a turbine runner 30.
The turbine runner 30T is connected to the input shaft 1, and the pump impeller 30P is connected to an engine (not shown).

FIG. 6 shows a hydraulic control circuit of the automatic transmission, and 20 shows an oil pump driven by an engine (not shown). 22 to 26 are respectively friction fastening elements 1
2 to 16 are hydraulic control valves for controlling the respective elements by selectively supplying oil from the pump 20 to the corresponding friction engagement elements by these hydraulic control valves. These hydraulic control valves 22 to 26 have, for example, solenoids and form an electric-hydraulic control system.

FIG. 7 shows a microcomputer 40 for controlling the above-mentioned hydraulic control valve, which also serves as a positive / negative torque discriminating means and comprises a CPU 41, a memory 42, an input / output interface 43 and the like. The hydraulic control valves 22 to 26 described above are connected to the output of the interface 43, and control these hydraulic control valves in accordance with a command from the CPU 41. A vehicle speed sensor 50 and a throttle opening sensor 51, for example, are connected to the input of the interface 43 and send a vehicle driving state signal to the CPU 41. Further, as shown in FIG. 5, rotation speed sensors 60 and 61 are provided as input rotation speed detection means and output rotation speed detection means for respectively detecting the rotation speed of the pump impeller 30P and the rotation speed of the turbine runner 30T in the torque converter 30. , These are also interface 4
Connect to the 3 input port.

Next, the operation of the above embodiment will be described by taking an upshift from the first speed to the second speed as an example. In the first speed state, the low clutch 12 and the low & reverse brake 13 are hydraulically supplied and are engaged as shown in the table of FIG. Here, when the shift to the second speed is determined based on the signals from the vehicle speed sensor 50 and the throttle opening sensor 51, first, from the magnitude of the rotation speed of the pump impeller 30P of the torque converter 30 and the rotation speed of the turbine runner 30T. It is determined whether the power-on traveling or the coasting traveling, and the shift control described later is performed according to the determination result.

Flow charts for these judgments and controls are shown in FIGS. 8 and 9. F used in this flow chart is a flag indicating a shift sequence, and its meaning is as follows. F = 0; indicates non-shifting. F = 1; indicates that power-on traveling is performed at the start of gear shifting. F = 2: Indicates a so-called torque phase during power-on traveling. F = 3: Indicates a so-called inertia phase during power-on traveling. F = 4: Indicates that the vehicle is coasting at the start of gear shifting. F = 5: Indicates a so-called inertia phase during coasting.

FIG. 8 (a) shows the main routine. At step a1, the engine load such as the throttle opening detected by the sensor 51 and the vehicle speed detected by the sensor 50 are read. A suitable gear position is determined from the combination of the engine load and the vehicle speed based on a predetermined shift pattern stored in memory, and the next step a3
Then, shifting from the current gear position to the preferred gear position is executed.

FIG. 8 (b) is executed only once when the shift from the first speed to the second speed is judged by the main routine of FIG. 8 (a). In step b1, the rotation sensors 60, 6
Pump impeller 30P and turbine runner 3 from 1 respectively
The rotational speeds N _P and N _T of 0T are read. Next step b2
Then, the control proceeds to step b3 or b4 depending on the magnitude of the rotation speeds N _P and N _T read in step a1. That is, the control proceeds to step b3 when the power-on traveling is N _P > N _T , and the control proceeds to step b4 when the inertia traveling is N _P <N _T. At steps b3 and b4, the flag F is set to "1" or "4" to indicate the respective traveling states, and the process returns to the main routine.

FIG. 9 shows a routine interrupt routine for gear shift control which is repeatedly executed at regular intervals. First, in step c1, the value of the flag F is discriminated, and the control is terminated as it is during non-shifting of F = 0, but if F is other than 0, steps c2, c7, c10, c13 corresponding to the values of 1 to 5 are performed. c15
Control to either of. In gear shifting during power-on traveling, the flag F = 1, so control proceeds to step c2. In step c2, for example, the target hydraulic pressure _PSB0 of the band brake 14 during the shift according to the detected values of the vehicle speed sensor 50 and the throttle opening sensor 51 is read from the memory 42 (see FIG. 7). The target oil pressure _PSB0 is assumed to be stored in the memory 42 in advance.

In the next step c3, the delay time t _d is read from the vehicle speed and the throttle opening detected by the sensors 50 and 51, as in step c2. This delay time t
_{In d} , the hydraulic pressure actually increases after the hydraulic signal is output.
It is assumed that the time until the so-called torque phase is completed is also stored in the memory 42 in advance. In step c4, the signal S _SB corresponding to the target oil pressure _PSB0 read in step c2 is output to the hydraulic control valve 24. At step c5, a timer for measuring the delay time is started (t = 0). This timer is incremented by 1 at fixed time intervals by hardware.

At step c6, during the torque phase.
Flag F to 2 to indicate that
Get After that, the flag F = 2 because the torque phase is in progress.
Therefore, the control advances from c1 to c7. In step c7,
The timer value t and delay time t_dAnd t> t
_dIf so, it is determined that the torque phase has not ended yet.
Then, the control ends without doing anything. t ≧ t_dWhen
Control proceeds to step c8, and low & reverse
Hydraulic signal S of the brake 13_LRTo 0 and release the brake
Issue a command to Then, in step c9, the flag F is set to
Set to “3” to indicate that the inertia phase is in progress, and control
To finish.

In the inertia phase, since the flag F = 3 is set as described above, the control advances from step c1 to step c10. At step c10, for example, it is determined from the vehicle speed and the rotation speed of the turbine runner 30T whether or not the shift is completed. If the shift has not ended, the control is ended as it is. If the shift has been completed, the control advances to step c11 to output a signal corresponding to the hydraulic pressure control valve 24 so that the hydraulic pressure of the band brake 14 is sufficiently high. At the next step c12, since the shift is completed, the flag F is set to 0 to indicate this and the control is completed.

During coasting, since flag F = 4, step c1 selects step c13. This step c
At 13, the signal S _LR = 0 is output to the hydraulic pressure control valve 22 so that the transmission torque of the low & reverse brake 13 _becomes zero. In the next step c14, the flag F is set to "5" so as to indicate that the inertia phase is during inertial running.
To finish the control. In the inertia phase after that, since F = 5, the control advances from step c1 to step c15. In step c15, for example, from the vehicle speed and the rotation speed of the turbine runner 30T, it is determined whether or not the rotation speed of the rotary element that is fastened by the band brake 12 is in synchronization with the band brake 14, that is, in this case, the rotation speed is zero. If the rotation is not synchronized, the control is terminated as it is, and if it is synchronized, the control is advanced to step c16. In step c16, a signal S _SB corresponding to a sufficiently high hydraulic pressure for engaging the band brake 14 at once is output to the hydraulic control valve 24. And the next step c17
Then, the flag F is set to "0" to indicate the end of the shift.

Although the operation of the 1-> 2 upshift gear shift has been described above, it goes without saying that the same applies to other gear shift operations.

The timer may be incremented not by hardware but by software. In this case, for example, a step of executing t = t + 1 may be provided before or immediately after step c1. Further, the loop of the flags F = 1 and F = 4 is executed only once immediately after the start of the gear shift, so that steps c2 to c6 instead of step b3.
And replace steps c13 to c instead of step b4.
14 may be replaced and the loop may be omitted from FIG. Further, the rotation speed sensor 60 of the pump impeller 30P in the torque converter 30 may be an engine rotation speed sensor generally installed in an engine (not shown).

[0028]

As described above, the automatic transmission according to the present invention is described in claim 1.
As described in, the input / output speed of the fluid transmission connected to the torque transmission path is detected, and whether the input torque to the torque transmission path is positive or negative is determined based on the result of comparing the magnitudes of both, and power-on traveling or coasting is performed. Since it is configured to make such a determination, it is more accurate than the conventional one that makes the determination based on the engine load, without being affected by the drive load of engine accessories, changes over time, and disturbances such as road gradients. It is possible to contribute to the shift control by determining whether the input torque is positive or negative, that is, whether it is power-on traveling or coasting.

[Brief description of drawings]

FIG. 1 is a transmission system diagram showing a general two-stage forward transmission using one planetary gear set.

FIG. 2 is an operation time chart showing gear shifting in a power-on traveling state in the transmission of FIG.

FIG. 3 is an operation time chart when another control logic is adopted, which shows gear shifting in a power-on traveling state in the transmission of FIG.

FIG. 4 is an operation time chart showing a gear shifting operation in a coasting state in the transmission of FIG.

FIG. 5 is a transmission system diagram showing an embodiment of an automatic transmission according to the present invention.

FIG. 6 is a hydraulic system diagram for gear shift control in the automatic transmission of the same example.

FIG. 7 is an electronic system diagram for gear shift control in the automatic transmission of the same example.

FIG. 8 is a flowchart showing a gear shift determination routine and an input torque positive / negative determination routine of a control program executed by the electronic control system.

FIG. 9 is a flowchart showing a shift control routine of the control program.

[Explanation of symbols]

1 Input Shaft 2 Output Shaft 5 Transmission Case 10 Front Planetary Gear Set 10S Sun Gear 10C Carrier 10R Ring Gear 11 Rear Planetary Gear Set 11S Sun Gear 11C Carrier 11R Ring Gear 12 Low Clutch 13 Low & Reverse Brake 14 Band Brake 15 High Clutch 16 Reverse Clutch 20 Oil Pump 22 Hydraulic control valve 23 Hydraulic control valve 24 Hydraulic control valve 25 Hydraulic control valve 26 Hydraulic control valve 30 Torque converter (fluid transmission device) 30P Pump impeller 30T Turbine runner 30S Stator 40 Microcomputer (positive / negative torque discriminating means) 41 CPU 42 Memory 43 Input Output interface 50 Vehicle speed sensor 51 Throttle opening sensor 60 Pump impeller speed sensor Input rotational speed detecting means) 61 turbine runner rotational speed sensor (output rotational speed detecting means)

Claims (1)

[Claims] 1. A fluid transmission device is provided, and a torque transmission path connected to the device is switched by a torque transmission path switching element to realize a multi-stage gear ratio, and the transmission torque of the torque transmission path switching element is arbitrary. In the controllable automatic transmission, the input rotation speed detecting means for detecting the input rotation speed to the fluid transmission, the output rotation speed detecting means for detecting the output rotation speed from the fluid transmission, A positive / negative torque discriminating means for discriminating the positive / negative of the torque input to the torque transmission path by judging the magnitude of the input rotational speed and the output rotational speed based on the signal from the output rotational speed detecting means, The hydraulic pressure supply / discharge control logic for the transmission path switching element is switched according to the positive / negative of the input torque to the torque transmission path determined by the positive / negative torque determination means. Automatic transmission, characterized in that the so that configuration.