JPS6262050A - Speed change shock reducing device for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce a speed change shock by a cheap device, by recognizing a waveform change of torque of an output shaft in an automatic transmission, when it performs a speed change, while evaluating speed change action for whether it is good or not and detecting a special phenomenon so as to control the torque of the output shaft feeding back its change. CONSTITUTION:A device, being equipped with a sensor 101 detecting a change of torque of the output shaft in an automatic transmission 100, recognizes a waveform change of torque of the output shaft, detected by said sensor 101, by a waveform recognizing means 102 while evaluates speed change action for whether it is good or not by a speed change action quality discriminating means 103 on the basis of a recognition result of said means 102. While the device detects by a detecting means 106 a change of torque of the output shaft, due to a special phenomenon appearing when the speed change action is finished, in the waveform change of torque of the output shaft recognized by the above described recognizing means 102 when a speed change is performed. And the device, in accordance with evaluation by the above described discriminating means 103 or an output of the rack removal detecting means 106, regulates the pressure of fluid, supplied to a speed change fluid pressure type friction element 105, by a fluid pressure regulating means 104.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to automatic transmissions for vehicles, and particularly relates to a shift shock reduction device for automatic transmissions that can reduce shift shock. O (Conventional Technique wI) Conventional gear shift shock reduction devices for automatic transmissions include, for example, Japanese Patent Application Laid-Open No. 52-106064 and Japanese Patent Application Laid-open No. 53-85.
There is one described in No. 264.

The conventional device described above detects the output shaft torque of an automatic transmission with a torque sensor, and changes gears while feeding back a detection signal of the output shaft torque so that the output shaft torque changes in accordance with a preset torque change. The aim is to reduce shift shock by controlling the fluid pressure of the hydraulic friction elements used in the transmission.

(Problems to be Solved by the Invention) However, in the conventional device described above, the output shaft torque of the automatic transmission is detected by a torque sensor, and this detection signal is fed back, while the actual change in the output shaft torque is detected in advance. Since the configuration performs real-time control in accordance with set torque changes, if you try to perform this control using a digital calculation circuit such as a microcomputer, you will need an expensive device that can perform high-speed calculations. Due to the real-time control described above, if error components such as noise are mixed into the torque sensor output, control accuracy will immediately decrease.To prevent this, it is necessary to use a highly accurate torque sensor, that is, an expensive A torque sensor is required.

Furthermore, the shift shock is caused by a sudden change in the output shaft torque of the automatic transmission, and this often occurs mainly because the friction elements for shifting are engaged in a short period of time.

Therefore, it may be possible to solve the above problem by lowering the supply pressure to the friction element during gear shifting, slowing down the engagement speed, and increasing the time required for shifting, but in this case, the friction If the supply pressure to the element is lowered, the period during which the friction element is in a semi-engaged state (hereinafter referred to as the "period") becomes longer, and there is a possibility that the friction element will wear out more quickly.

In addition, in an attempt to prevent wear of the friction elements, if the supply pressure to the friction elements is increased to shorten the time required for shifting,
Large torque fluctuations (this is referred to as "shelf shear") occur after the friction elements are engaged.

In other words, as shown in Fig. 7(a), if a relatively long slip period (the fastening operation starts at time ta and the fully fastened state is reached at time tD) is selected, the output shaft torque can be smoothly adjusted. torque and does not cause sudden torque fluctuations.

However, if the above specified period is shortened, Fig. 7(b)
, As shown in (0), the residual energy in the hatched area in the figure is transmitted to the output shaft at once when the friction element is fastened. Torque fluctuations TH□ and TH2 (the above-mentioned "shelf deviation") occur, resulting in a start shock.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes the means shown in FIG. Recognizing the fluctuating waveform of the output shaft torque 〇 The gear shifting operation quality determining means 103 evaluates the quality of the shifting operation based on the fluctuating waveform of the output shaft torque at the time of shifting recognized by the waveform recognizing means 1020 Shelf deviation detection The means 106 is a fluid pressure adjusting means for detecting the fluctuation of the output shaft torque due to the shelf shearing phenomenon that appears at the end of the shift operation as described above, in the fluctuation waveform of the output shaft torque during the shift recognized by the waveform recognition means. 104 is a gear shift operation quality determining means 103
The fluid pressure supplied to the fluid pressure type friction element 105 for gear shifting constituting the automatic transmission 100 is determined according to the evaluation by adjust.

(Function) The waveform recognition means 102 and the shift operation quality determination means 103
Also, the shelf deviation detection means 106 feeds back changes in the output shaft torque by evaluating the quality of the gear shifting operation and detecting the shelf deviation phenomenon based on the fluctuating waveform of the output shaft torque during gear shifting. This can be realized using a digital circuit that requires a slower calculation processing time than a conventional device that feeds back the detected value of the output shaft torque in real time and compares it with a preset torque change.

Further, the fluid pressure adjusting means 104 controls the fluid pressure supplied to the fluid pressure type friction element 1-05 according to the evaluation by the shift operation quality determining means 103 or the presence or absence of a shelf deviation phenomenon detected by the shelf deviation detection means 106. Even if an error component such as noise is mixed in the detection signal of the sensor 101, it is possible to evaluate the quality of the gear shifting operation without being influenced by this error component, and it is possible to Since there is no problem in detecting the shearing phenomenon, there is no need to use a high-precision sensor for the sensor 101, and costs can be reduced. This makes it possible to reduce the shift shock that occurs when

(Example) The configuration of one embodiment of the present invention is shown in FIG.

The control circuit Wrzo is mainly composed of a digital arithmetic circuit constructed using a microcomputer or other digital circuit. In the figure, some functional blocks are shown to make the control functions easier to understand.

The information input to the control circuit 20 is the output shaft torque TOU of the automatic transmission (as shown) detected by the torque sensor 10.
T, the throttle opening S detected by the throttle opening sensor 11, the output shaft rotation TH', and the rotation speed 'OUT of the output shaft of the automatic transmission detected by the number sensor 12.

The torque sensor 10 is a well-known magnetostrictive torque sensor (similar to the one described in the above-mentioned conventional publication), and the output signal is an analog signal, so the control circuit 20
The signal is converted into a digital signal by an A/D converter 80 within the unit. The output signals of the throttle opening sensor 11 and the output shaft rotation speed sensor 12 are digital signals.

The output signal outputted from the control circuit 20 is a drive signal for the pressure control valve 40 that controls the fluid pressure of the hydraulic friction element for gear shifting that constitutes the auxiliary transmission mechanism of the automatic transmission.

As shown in FIG. 8, the pressure control valve 40 is composed of a spool valve 51 and a solenoid pulp 52, and controls the supply pressure PL (which is the output pressure from the oil pump) supplied to the input oil path 55. Fixed orifice 58 and variable orifice 58 whose opening degree is adjusted by solenoid valve 52
By applying the control pressure PC to the spool pulp 51, the amount of displacement of the spool 518 is adjusted, and as a result, the output pressure Ps from the output oil passage 56 is adjusted.

The output oil passage 56 is connected to the hydraulic oil supply passage of the hydraulic friction element.

The drive signal supplied from the control circuit 20 to the pressure control valve 40 is the excitation current of the solenoid pulp 52, and this drive signal is the PW in the control circuit 20.
This is a pulse width modulated current signal output from the M circuit (pulse width modulation circuit) 81.

That is, by changing the ON/OFF duty ratio of the drive signal using the PWM circuit 81, the amount of displacement of the spool 52S of the solenoid valve 52 is adjusted, and the opening degree of the variable orifice 54 is adjusted. As a result, the output pressure Ps is adjusted.

The control circuit 20 inputs each of the above input information TOUT, 5Tl(
= NOUT determines the oil pressure to be applied to the hydraulic friction element for gear shifting and performs control to reduce gear shifting shock.The functional structure of the system is shown in Fig. 2. It consists of numbers 21 to 29.

The shift point determining unit 21 determines the gear position of the automatic transmission based on the throttle opening "TH" and the output shaft rotational speed N0UT.

When the gear position is determined by the shift point determining unit 21, the pressure determining unit 22 determines when the gear position changes, that is, when a gear shift is performed, and applies pressure to the hydraulic friction element for gear shifting during this gear shift. (This set time change in supply pressure is referred to as the "reference pressure change".)
0 waveform recognition unit 24 output shaft torque T. U, is input to detect the magnitude of the output shaft torque TOUT during gear shifting.

Based on the magnitude of the output shaft torque TOUT measured by the waveform recognition unit 24, the quality determining unit 25 determines whether the gear shifting operation will cause discomfort to the driver when one gear shifting is performed. Determine whether a large peak torque that would cause a sudden change in acceleration is occurring.

The shelf deviation detection section 26 detects whether or not a fluctuation in the output shaft torque has occurred due to the above-mentioned shelf deviation phenomenon using the waveform recognition section 24.
The storage unit 27 is a memory, and stores information such as the type of gear change and operating conditions, the quality determining unit 2″5, and the shelf deviation detection unit 26.
According to each determination result, the correction amount Δ of the supply pressure to the friction element
Preset data is stored as a data table to determine the time Jc required for shifting within an allowable length (hereinafter referred to as "allowable shifting time") taking into account P1 and the wear resistance of the friction elements. There is.

The pressure change correction unit 28 determines the pressure to be supplied to the friction element to be applied during gear shifting based on the reference pressure change set by the pressure determining unit 22 and the pressure correction amount ΔP. Based on the change point of the output shaft torque recognized by the section 24, the time required for the shift operation (hereinafter referred to as "shift required time JH") is measured, and this shift required time JH is stored in the storage section 27. The allowable shift time J determined from the data table. It is determined that the time when the shift operation reaches the end point is the end of the gear shifting operation.

The pressure control section 29 controls the pressure change correction section 28 until the end of the shift.
Based on the supply pressure determined in , an output (hereinafter referred to as "pressure command value P") for forming a drive signal to be applied to the pressure control valve 40 is generated.

Next, FIGS. 4 to 6 show the control circuit 2o when the control circuit 2o is configured using a microcomputer.
4, which is a flowchart showing the processing executed in 0.
The processes shown in FIGS. 6 to 6 are a series of processes that are repeatedly executed at predetermined time intervals. In the process of step 61 in FIG.
Each input data of H and output shaft rotational speed N0UT is read.

In step 62, the content of the 7-lag F for control mode determination is determined, and it is determined which routine to proceed to thereafter. This flag F is set with 2-bit data t'L, "
When it is 00J, it is "no shifting", and when it is "01", it is "no shifting".
Shifting", 10j: Shifting", 10j: Shifting
.

Furthermore, when the ignition switch is turned on,
Flag F is reset to "OO".

Assuming that the result of the determination in step 62 is 7 lag F = 00, then in the process of step 63 the operating conditions are determined, and in the process of step 64 the shift diagram stored in advance in the memory is Based on this, it is determined whether the above operating conditions (throttle opening degrees S, H and output shaft rotational speed N, determined by UT) exceed a shift point that requires a shift.

Here, if the driving conditions are not such that shifting is required,
Exit the routine without taking any control. On the other hand,
If a shift is required, steps 66 to 69 are executed.

In step 66, the fluid pressure PF to be applied to the fluid pressure friction element for gear shifting is determined by lookup processing of the pressure data data tape /I/ (hereinafter referred to as "pressure data table") stored in the memory. demand.

The above pressure data table shows the type of speed change (for example, “1
There are multiple cases depending on the operating conditions (throttle opening STH, output shaft rotational speed N0UT, vehicle speed, etc.) The required pressure data under these conditions is stored.

In the next step 67, a data table (hereinafter referred to as "correction data table") of correction amount data stored in the memory is
), the above step 66 is performed.
A correction amount (one time correction amount) is calculated for the pressure data obtained in , and the pressure data P is corrected by this correction amount ΔP.

In step 68, the pressure data corrected in step 67 is output as a command value for the supply pressure of the friction element (the above-mentioned pressure command value P).

This pressure command value P is output to a friction element that needs to perform pressure control determined in accordance with the type of speed change. The pressure command value P is then supplied to the PWM circuit 31 and converted into a drive signal for the E-force control valve 40. As a result, the fluid pressure supplied to the friction element becomes equal to the pressure command value P.

By executing the above steps 66 to 68, the actual gear shifting operation is started. Therefore, in the next step 69, the flag F is set to l'-o IJ to memorize that "shifting" is in progress. 0 When the speed change operation is started as described above, the process of step 71 is then executed based on the result of the determination of the contents of the flag F performed in step 70 of FIG. Start up and output shaft torque T. UT data is read. Then, in the next step 72, after the start of the speed change operation, a process is performed to detect the point in time when the engagement of the friction elements starts. This is a determination process, and at this point ta, the output shaft torque TOUT fluctuates (due to a change in load due to inertia component, etc.) because the friction element has started to engage and the clutch plate has started to press. , the output shaft torque T rapidly. , 0, which is the point at which T starts to decrease. Therefore, in the process of step 72, the output shaft torque T read in step 71. When the output shaft torque TOUT decreases a predetermined number of times in succession compared to the output shaft torque read in UT in the previous process, and the amount of decrease in the output shaft torque during this period is greater than or equal to the predetermined value, the above It is determined that it is the engagement start time ta of the friction element. When the engagement start time ta is detected, the processes of steps 73 and 74 are then performed.
Process 74 is a process for recognizing the fluctuating waveform of the output shaft torque TOUT accompanying the gear shifting operation. This recognition of the fluctuating waveform of the output shaft torque TOUT determines the peak torque TP of the output shaft torque TOUT during the gear shifting period. That is, in step 73, the timer counter is started from the time when the above-mentioned fastening start time t is detected, and the 0 peak torque Tp is measured to measure the elapsed time JK from the time ta.
The measurement is the output shaft torque T read in step 71.

Repeatedly compare U with the output shaft torque read in the previous process every time the routine process is performed, find the largest value during the shift period from these comparison results and their magnitude relationship, and use this as This is done by setting the peak torque to TP.

The processes in steps 73 and 74 are repeated until the end of the shift is detected in step 75.

In step 75, the end of the shift is determined by determining the allowable shift time J corresponding to the operating conditions from a data table of allowable shift time data stored in the memory in advance.

This Jc is compared with the elapsed time JK, and JK
It is determined whether or not the shift is completed based on whether or not ≧Jc.

The above allowable shift time J. is set for each operating condition in consideration of the wear resistance of the friction elements, since if the sliding period of the friction elements is longer than necessary, the friction elements will wear out quickly.

When the above-mentioned Jx ≧ JO is established and the end of the shift is detected, the process of step 76 causes a command to generate a supply pressure that brings the friction element into a fully engaged or fully released state, instead of the pressure command value P. Outputs a value signal ◇In other words, in the case of complete engagement, the duty ratio of the drive signal is 100
% (expressed as a duty ratio of ON time), and in the case of complete release, a command value signal is generated such that the duty ratio becomes 0%. As a result, in the zero-order step 77 where the actual gear shifting operation is completed, the processes of steps 73 and 74 are further repeated at Δt so that the peak torque T is measured only for a certain period of time Δt after the end of the gear shifting. Execute only for a while. This is performed by determining JK≧(Jo+Δt).

That is, by measuring the peak torque Tp for a certain period of time after the end of this shift, the output shaft torque TOUT
The aim is to detect the torque fluctuation pattern caused by the above-mentioned "shelf shearing" phenomenon from the fluctuation waveform of By setting , the processes of steps 80 to 90 shown in FIG. 6 are executed.

In the process of step 80.81, it is determined whether or not the peak torque measured in step 74 is less than or equal to a predetermined reference value TR, and when TP≦TR, it is determined that the gear shifting operation has been performed satisfactorily. It is determined that it is a thing.

This is because the generation of an unnecessarily large peak torque causes shift shock.

Here, if it is determined that the gear shifting operation was performed well, there is no need to adjust the supply pressure of the separate friction element, so the 7 lag F is reset in step 90 and the process ends. do.

On the other hand, if it is determined that the gear shifting operation has not been performed satisfactorily, the process of step 82 determines whether or not the peak torque TP larger than the reference value TR is due to "shelf slippage". In step 77, if the peak torque TP is measured during a certain period of time after the end of the speed change operation, it is determined that the problem is due to shelf displacement.

Here, the peak torque T, which is larger than the reference value, is
If it is determined that it is due to “Tanabazu n”,
Next, in the process of step 83, it is determined whether or not "shelf deviation" was detected during the previous speed change operation.

If "shelf slipping" occurred last time, the cause is that the supply pressure to the friction element is too low, so the pressure correction test should be performed to increase the supply pressure the next time the gear is shifted. Determine 〇 (Step 85) o This pressure correction amount A□ is a larger value than the pressure correction amount ΔP obtained in Step 67 in the current shift operation, and corresponds to the magnitude of the peak torque -Tp. , the magnitude thereof is determined. Further, when the determination in step 83 is No, it means that the shelf deviation j did not occur during the previous shift operation, but it occurred this time. This is because the pressure correction amount (this is referred to as "Bo") obtained in the previous shift operation was a value that reduced the supply pressure excessively, so at the next shift, the supply pressure will be increased more than this time. A pressure correction amount A is determined so as to make the change (step 87).

On the other hand, if the determination in step 82 is No, the peak torque Tp exceeding the predetermined value generated in the current shift operation is not due to "shelf slippage" and is due to the This shows that the peak of the fluctuation in the output shaft torque caused by the release of the inertia component when the gear ratio is changed during the gear shift is large.

Therefore, in order to reduce this peak torque TP, it is sufficient to reduce the supply pressure to the friction element.

Here, in step 84, "
If "shelf deviation" has occurred, the supply pressure cannot be lowered more than necessary, so in step 86, a pressure correction amount B is calculated that is smaller than the pressure correction amount B2 determined in step 88. Ru.

However, the pressure correction amounts B□ and B2 are negative values, and their magnitudes are determined according to the magnitude of the peak torque TP.

In step 89, the pressure corrections ff1A□, A2. B engineering and B2 are replaced with pressure correction amount data ΔP at a position in the correction data table corresponding to the same conditions and type as the operating conditions and type of speed change during the current speed change operation.

As a result, when a shift is performed again under the same conditions and type as this time, the pressure command value P will be determined using the pressure correction amount ΔP that has been replaced with the pressure correction amount, and as a result, the pressure command value P will be more accurate. Appropriate supply pressure will be applied to the friction element.

As described above, in this embodiment, each time a gear shifting operation is performed,
Evaluate the quality of the shift operation by determining the magnitude of the peak torque Tp and detect "shelf deviation", and depending on these,
By correcting the pressure correction amount ΔP used in the next shift,
The supply pressure to the friction element can be adjusted in a direction that reduces shift shock.

In the above embodiment, the torque sensor 10 is used as a sensor for detecting a change in the output shaft torque of an automatic transmission, but an acceleration sensor may also be used for detection. However, the use of a torque sensor has the advantage of being able to detect the actual engagement start time ta of the friction elements, and thus allowing more accurate adjustment of the allowable shift time.

(Effects of the Invention) As described in detail above, the present invention recognizes the fluctuating waveform of the output shaft torque during shifting of an automatic transmission, and evaluates the quality of the shifting operation and detects the shelving phenomenon. By feeding back the changes in the output shaft torque, the calculation process is faster than conventional devices, which feed back the detected value of the output shaft torque in real time and compare it with a preset torque change. It can be realized using slow digital circuits. Kneading leads to cost reduction.

In addition, by adjusting the fluid pressure supplied to the fluid pressure type friction element based on the evaluation of the quality of the shift operation or the presence or absence of shelf shearing, the detection signal of the sensor that detects changes in the output shaft torque can be adjusted. Even if an error component such as noise is mixed in, there is no problem in detecting this error and the shelf shearing phenomenon, so there is no need to use a high-precision sensor as the sensor, and costs can be reduced.

In particular, the present invention can reduce the shift shock that occurs due to the output shaft torque fluctuation due to the above-mentioned shelf shearing phenomenon.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a sectional view showing the specific configuration of the pressure control valve in FIG. 2, and FIG. Figures 7 to 6 show the processing executed by the control circuit in Figure 2, and Figures 7 (a) to (C) show the shearing phenomenon caused by the length of the slip period. FIG. 100... Automatic transmission 101... Sensor 10
2... Waveform recognition means 108... Transmission operation quality determination means 104... Fluid pressure adjustment means 105... Fluid pressure type friction element 106... Shelf deviation detection means 10... Torque sensor 11... Throttle opening Degree sensor 12... Output shaft rotation speed sensor 20... Control circuit 4o... Pressure control valve T
P Beak torque TOUT...Output shaft torque ΔP Pressure correction amount A, A2. Work B, B2...Pressure correction amount Fig. 1

Claims (1)

[Scope of Claims] 1. A sensor that detects a change in output shaft torque of an automatic transmission; a waveform recognition means that recognizes a fluctuation waveform of the output shaft torque detected by the sensor; and a waveform recognition means that recognizes a fluctuation waveform of the output shaft torque detected by the sensor. a shift operation quality determination means for evaluating the quality of the shift operation based on the recognized fluctuation waveform of the output shaft torque during the shift operation; a shelf deviation detection means for detecting fluctuations in output shaft torque due to a shelf deviation phenomenon that appears at the end of a gear shifting operation; A gear shift shock reduction device for an automatic transmission, comprising: fluid pressure adjusting means for adjusting the fluid pressure supplied to a fluid pressure type friction element for gear shifting constituting the automatic transmission, depending on the presence or absence of fluctuation. .