JPH0587219A - Hydraulic controller of automatic transmission - Google Patents

Abstract

PURPOSE:To provide a hydraulic controller of an automatic transmission which is able to set a proper amount of hydraulic pressure at the time of speed adjustments. CONSTITUTION:When working pressure in a transmission is set up on the basis of a torque signal Tt representing a torque being inputted into the automatic transmission as well as when a variation in this torque signal Tt or throttle opening TH is more than the specified value, the working pressure is compensated as specified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device during shifting of an automatic transmission, and more particularly to a hydraulic control device for ensuring a hydraulic pressure that properly follows changes in the engine load or torque change rate. is there.

[0002]

2. Description of the Related Art In a conventional automatic transmission, a shift command is controlled.
What does it mean in the transmission after leaving the control device?
The control of whether the gears are shifted in the same way is as follows:
The control of the line pressure that governs the operation of the rubbing element
Torque T_tAnd turbine speed N _t Control according to
For example, Japanese Patent Laid-Open No. 2-38749) is the best option.
It

[0003] In the former case, the line pressure may be, for _{example, PL = A · T t +} B · N t + C (A, B, C is a constant) is set in accordance with ‥‥‥ (1). Since the line pressure acts as the operating pressure of the torque converter and the operating pressure of the brake, the clutch, etc., the line pressure is controlled according to the turbine torque T _t and the turbine rotation speed N _t as shown in equation (1). That's a reasonable place.

[0004]

However, even under various operating conditions, the above-mentioned control may not be able to be coped with, and a shift shock may occur. For example,
It is assumed that a shift command is issued because the shift line is crossed during throttle operation (during accelerator operation). In this case, the line pressure generated cannot keep up with the depression speed of the throttle due to the response delay of the hydraulic control, so that the clutch capacity may be insufficient with respect to the increased engine torque. If the capacity is insufficient, the clutch may slip, and in the worst case, seizure may occur.

This response delay is due to the fact that the torque detected by the torque sensor is behind the actual torque as shown in FIG. 1, and also due to the response delay of the hydraulic control itself. And
This problem does not occur only during shifting, but also during acceleration / deceleration during normal traveling. Therefore,
The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object thereof is to propose a hydraulic control device for an automatic transmission, which can set an appropriate hydraulic pressure during acceleration / deceleration. ..

[0006]

A hydraulic control device for an automatic transmission according to the present invention to achieve the above object is provided on an input shaft of the automatic transmission and represents a torque input to the automatic transmission. A torque sensor for picking up a signal, an operating pressure setting means for setting the operating pressure of the transmission based on the torque signal from the torque sensor, and the operating pressure setting means when the rate of change of the torque signal is a predetermined value or more. And a correction means for correcting the operating pressure set by.

Another structure of the present invention is based on a torque sensor which is provided on an input shaft of an automatic transmission and picks up a signal representing torque input to the automatic transmission, and a torque signal from the torque sensor. First to set the operating pressure of the transmission
Operating pressure setting means, means for detecting the engine load,
Second operating pressure setting means for setting the operating pressure of the transmission on the basis of the detected engine load, and set by the first operating pressure setting means when the rate of change of the torque signal is equal to or greater than a predetermined value. Switching means for switching the operating pressure to the operating pressure set by the second operating pressure setting means.

Still another configuration of the present invention is based on a torque sensor which is provided on an input shaft of an automatic transmission and picks up a signal representing a torque input to the automatic transmission, and a torque signal from the torque sensor. First operating pressure setting means for setting the operating pressure of the transmission by means of the above, means for detecting the engine load, and second operating pressure setting means for setting the operating pressure of the transmission based on the detected engine load. When the rate of change of the detected engine load is equal to or greater than a predetermined value, the first
Switching means for switching the working pressure set by the working pressure setting means to the working pressure set by the second working pressure setting means.

That is, according to the above-mentioned invention, the shortage is compensated in a region where there is a concern that the working pressure is insufficient such that the engine load and the torque vary greatly. This deficiency is made according to a change in engine load (for example, throttle opening) or a change in torque.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a hydraulic control system for an automatic transmission according to the present invention will be described below with reference to the accompanying drawings. The present embodiment is particularly characterized by the line pressure control during normal traveling in which gear shifting operation is not performed. First, the torque sensor used in this embodiment will be described, then the automatic transmission of the embodiment will be described, and then the control procedure of the controller will be described.

FIG. 2 shows the structure of the torque sensor used in the automatic transmission of this embodiment. In the figure, reference numeral 1 denotes a turbine shaft (rotary shaft) made of an iron-based material, and the turbine shaft 1 has first and second turbine shafts spaced from each other in the axial direction.
Magnetic recording units 2 and 3 are provided. Then, the first and second magnetic heads 4 and 5 are arranged so as to face the first and second magnetic recording units 2 and 3, and a signal obtained from the magnetic heads 4 and 5 is processed by a signal processing circuit. The processing is performed in step 6 and is given to the controller 100 of the automatic transmission.

As shown in FIG. 3, each of the magnetic recording portions 2 and 3 has a non-magnetic film 8 and a magnetic film 9 provided thereon.
It is formed in a ring shape over the entire circumference of the turbine shaft 1. The non-magnetic film 8 is for preventing leakage of magnetic flux to the turbine shaft 1 when a signal is recorded on the magnetic film 9 by the magnetic heads 4 and 5. In the case of this example, it is made of an aluminum-based metal. It is formed by thermal spraying. On the other hand, the magnetic film 9 is used to record signals by the magnetic heads 4 and 5, that is, a position signal in the turbine shaft circumferential direction, and iron oxide mainly containing Fe ₃ O ₄ (ferric tetroxide). Is formed by thermal spraying.

The first and second magnetic heads 4 and 5 record the position signal in the magnetic recording units 2 and 3 at a predetermined frequency in the circumferential direction of the turbine shaft and reproduce the recorded position signal. It is a reproducing type head. Further, the signal processing circuit 6 includes a torque calculation unit that calculates a torque T _t output from the turbine shaft 1 based on the reproduction frequency of the position signals obtained by the magnetic heads 4 and 5, and a turbine based on the reproduction frequency. A rotation speed calculation unit that calculates the rotation speed N _t of the shaft 1 is provided. Further, the controller 100 executes shift control of the automatic transmission, line pressure control, shift shock mitigation control, etc. based on the detected torque T _t and rotational speed N _t .

FIG. 4 shows the engine 11 and the automatic transmission 12. In the figure, 13 is a throttle valve provided in an intake passage extending from the air cleaner 14 to the intake manifold 15, and 16 is an opening T of the throttle valve 13.
It is a throttle opening sensor that detects H. Also, 17
Is a torque converter that transmits the rotation of the crankshaft of the engine 11 to the turbine shaft 1 of the automatic transmission 12.

The automatic transmission 12 includes the torque converter 17 and an auxiliary transmission device having a planetary gear type transmission mechanism having friction engagement elements such as a multi-plate clutch and a band brake.
A plurality of hydraulic cylinders for operating the lockup clutch of the torque converter 17 and the friction engagement mechanism;
The control valve unit 18 is provided. The control valve unit 18 includes a line pressure control mechanism having a duty solenoid valve 19 for controlling the line pressure supplied to each hydraulic cylinder, and a plurality of shift solenoid valves 20 for controlling the supply / discharge of the line pressure to / from each hydraulic cylinder. And the automatic transmission 12 described above.
Built into the.

Next, the calculation of the torque T _t applied to the turbine shaft 1 and the calculation of the rotational speed N _t of the turbine shaft 1 by the signal processing circuit 6 will be described. First, in the first and second magnetic heads 4 and 5, the recording frequencies of the position signals to the magnetic recording units 2 and 3 of the turbine shaft 1 are different from each other.
As shown in, the first magnetic head 4 has a low recording frequency,
The second magnetic head 5 has a high recording frequency. The magnetic heads 4 and 5 record the position signals by matching the phases with each other in a state where the load torque does not act on the turbine shaft 1 (see FIG. 5). Therefore, when a load torque acts on the turbine shaft 1, the turbine shaft 1 is actually twisted. As a result, the reproduction frequencies of the position signals by the magnetic heads 4 and 5 are in phase with each other as shown in FIG. It shifts. The deviation amount Δt corresponds to the twist angle of the turbine shaft 1 and thus the load torque acting on the turbine shaft 1.

Then, the torque calculation is performed by
Based on the reproduction frequency of the heads 4 and 5, the deviation amount Δt is
The torque that is calculated and added to the turbine shaft 1 based on the following formula
Ku T _t Is to seek. T_t = Π² ・ G.・ D^Four ・ Δt ・ N_t / 16L where π is the circular constant, G is the lateral elastic modulus of the turbine shaft 1, and d
Is the diameter of the turbine shaft 1, N_t Is the rotational speed of the turbine shaft, L
Is the distance between the magnetic recording portions 2 and 3.

Further, the signal processing circuit 6 obtains the rotational speed N _t of the turbine shaft 1 by the following equation based on the reproduction frequency obtained by either one of the magnetic heads 4 and 5. N _t = N ₀ · f / f ₀ where N ₀ is the rotational speed of the turbine shaft 1 at the time of position signal recording,
f ₀ is the recording frequency at that time, and f is the reproduction frequency.

Next, the line pressure control mechanism of the automatic transmission 12 will be described with reference to FIG. In the figure, 21
Is a pressure reducing valve for receiving the hydraulic pressure generated by the pump P driven by the engine 11 from the oil passage 22 and reducing the pressure to a predetermined pressure.
3 is an oil passage for converting the oil pressure reduced by the pressure reducing valve 21.
4 is a throttle modulator valve that receives the above hydraulic pressure as a pilot pressure via a duty pressure passage 25 provided with a duty solenoid valve 19. The throttle modulator valve 23 generates throttle modulator pressure according to the duty ratio of the duty solenoid valve 19. In this case, on / off operation 1 of the duty solenoid valve 19
By controlling the on-time ratio (duty ratio) per cycle, the operating hydraulic pressure (duty pressure) in the duty pressure passage 25 is adjusted (the higher the duty ratio, the lower the duty pressure).

A line pressure control 26 receives the throttle modulator pressure via a pilot pressure passage 27, and adjusts the hydraulic pressure generated by the pump P to an optimum pressure for operating the hydraulic cylinder of the friction engagement mechanism at each shift stage. It is a valve. The pilot pressure passage 27 is provided with an accumulator 28 that absorbs a pulsation of hydraulic pressure in the passage and stabilizes the pilot pressure supplied to the line pressure control valve 26. This accumulator 28 includes a drain port 29 and a pressure exhaust port 30.
And has a function as a relief valve.

Further, in the line pressure control valve 26, 31 is a reverse oil passage communicating with the reverse port of the manual valve, 32 and 33 are first and second line oil passages communicating with the hydraulic cylinder of the friction engagement mechanism, and 34. Is a converter oil passage communicating with the torque converter 17, and 35 is a drain oil passage. The operation of the line pressure control valve 26 will be described. When the engine 11 is stopped and the line pressure is not applied, the converter oil passage 34 is closed by the bias of the spool 37 by the spring 36. When the engine 11 is started and the line pressure from the oil pump P acts from the first line oil passage 32, the spool 37 moves leftward against the pilot pressure and the biasing force of the spring 36, and the converter oil passage 34 is opened, and the converter hydraulic pressure acts on the torque converter 17. When the engine speed increases and the line pressure increases as the accelerator opening increases, the spool 37 further moves to the left and drains through the first line oil passage 32 and the drain oil passage 35. The line pressure becomes stable at a constant hydraulic pressure at a position balanced with the urging force of the pilot pressure and the spring 36.

Therefore, by controlling the duty ratio of the duty solenoid valve 19 by the controller 100 to adjust the duty pressure and thus the pilot pressure, the urging force of the pilot pressure and the spring 36 is controlled, and the urging force is balanced. The line pressure can be controlled. The controller 100 will be described. This is a microcomputer including a CPU, a ROM, and a RAM (not shown), an input / output interface, an A / D converter and a waveform shaping circuit, and a drive for the shift solenoid valve 20. A circuit and a drive circuit for the duty solenoid valve 19 are provided. Then, the ROM of the above microcomputer stores in advance a program for gear shift control, a program for line pressure control, and a gear shift shock alleviation control program.

In the shift control, the shift stage is determined based on the shift characteristic shown in FIG. 8, for example, based on the rotation speed signal N _t from the signal processing circuit 6 and the throttle opening signal from the throttle opening sensor 16. The content of the control is to control the shift solenoid valve 20 so that the shift stage is reached. In the line pressure control, the torque signal T _t and the rotation speed signal N _t from the signal processing circuit 6 are read to determine the line pressure PL supplied to the plurality of hydraulic cylinders of the friction engagement mechanism, and the duty solenoid valve is used. 19
It is intended to control the line pressure via the.
The present embodiment is characterized by the line pressure control during normal traveling in which gear shifting operation is not performed. That is, the set value of the line pressure PL is changed depending on whether or not the throttle opening TH exceeds a predetermined value. That is, if the rate of change of the throttle opening is represented by χ = dTH / dt, then when | χ | <A, PL = K ₁ · T _t + K ₂ · N _t + C, and when | χ | ≧ A , PL = K ₁ · T _t + K ₂ · N _t + C +
Let α (χ). Here, K ₁ and K ₂ are constants, and T _t and N _t are torque and rotation speed of the turbine shaft 1. C is a constant and α (χ) is a function of χ. We propose one of the two types shown in FIG. 12 as α (χ).

Α ₁ (χ) = C ₁ · χ or α ₂ (χ) = step function The characteristic of FIG. 12 is that the correction term becomes larger (smaller) as χ increases (decreases). Have By doing so, in a region where the absolute value of the time derivative of the throttle opening TH is smaller than the predetermined value, it is determined that the line pressure can follow the actual torque, and no correction is performed. However, in the region of | χ | ≧ A where it is considered that the actual torque of the engine cannot be followed, if the correction α (χ) is performed according to the change rate χ of the throttle opening, clutch slippage and clutch seizure will be eliminated.

FIG. 9 shows the mounting position of the torque sensor in this embodiment. This sensor is provided on the turbine shaft 1 of the torque converter 17. It is well known that the turbine shaft 1 is input to the speed change gear mechanism. The torque sensor may be provided at the rear stage instead of the front stage position of the gear mechanism as shown in FIG. However, when the sensor is provided in the subsequent stage, the sensor detects the torque signal T _P of the output shaft. Further, since T _P shows a slow change at point B, which is the point at which the actual shift operation starts, it is considered that the detection accuracy is low for detecting the inflection point. For this reason, the torque sensor is mounted on the turbine shaft 1 in this embodiment.

FIG. 10 is a flow chart showing a control procedure in the control circuit 100 for setting the line pressure for the purpose of alleviating the torque shock. Step S of FIG.
In 2, the vehicle speed V and the throttle opening TH are input to determine the shift line. In step S4, it is determined based on these signals whether or not the gear shifting operation is performed, and if not necessary, the process proceeds to step S6.

In step S6, the turbine torque T _t ,
The turbine speed N _t is read from each sensor. In step S8, the time derivative ω of the torque T _t is calculated. In step S10, the time derivative χ of the throttle opening TH is calculated. Then, in step S12, the absolute value of the time derivative χ of the throttle opening ω is compared with a predetermined threshold A.

As described above, when | χ | <A, PL = K ₁ · T _t + K ₂ · N _t + C (step S14), and when | χ | ≧ A, PL = K ₁ · Let T _t + K ₂ · N _t + C + α (χ) (step S16).

FIG. 12 shows a graph of the correction terms α ₁ (χ) and α ₂ (χ). That is, the function representing these correction terms gives a larger correction amount contribution to the line pressure as the change in the throttle opening becomes larger. In other words, if the throttle increases rapidly, the line pressure also increases, and if the throttle rapidly decreases, the line pressure also decreases.
Thus, the required line pressure corresponding to the rate of change of the throttle can be satisfied. Α indicated by the broken line graph in FIG.
₂ (χ) is a function that changes stepwise. This function type is easier to control by arithmetic operation.

The present invention can be variously modified without departing from the spirit thereof. Modifications will be described below with reference to FIGS. 11 and 12. In the control of the above embodiment (FIG. 10), the acceleration / deceleration state is identified by the change χ of the throttle opening (step S1).
2) I was doing. In the modified example described below, this determination is made based on the throttle opening. FIG. 11 shows a flow chart according to the modified example. The flow chart of FIG. 11 replaces step S12 of FIG. That is, instead of the change rate of the throttle opening, the process proceeds to step S14 or step S16 of FIG. 10 depending on whether the change rate ω of the torque calculated in step S8 of FIG. 10 is larger or smaller than the threshold value B.

The following modifications are proposed. In the above-described embodiment and the first modified example, whether the determination criterion for switching the set amount of line pressure is based on χ (time derivative of throttle opening),
Although there is a difference based on ω (time derivative of torque), the correction term is χ, that is, the throttle opening T
It was based on the time derivative of H. In the second modification, the correction term is a function of ω. That is, FIG.
In step S16 of, α ₁ (χ), in place of _{α 2 (χ), α 1} (ω), to define the _{α 2 (ω), α 1} (ω) = C 1 · ω or, alpha ₂ ( Let ω) = step function. Even in this case, in the second modified example, an effect similar to that of the embodiment and the first modified example can be obtained. In other words, clutch slippage and seizure machines are reduced. However, the time derivative χ of the throttle opening is a quantity that directly expresses acceleration / deceleration, whereas the time derivative of the torque T _t is an quantity that indirectly represents acceleration / deceleration. Can be said to be slightly less responsive.

The present invention can be further modified. For example,
Further, all the calculations in steps S14, S16, etc. can be obtained by a map.

[0033]

As described above, according to the hydraulic control system for an automatic transmission of the present invention, in a region where there is a concern that the operating pressure may be insufficient due to large fluctuations in engine load and torque, the shortage may cause engine load. It is compensated according to a change in (for example, throttle opening) or a change in torque. That is,
Even in an area where there is a concern that the operating pressure will be insufficient, responsiveness is set and an appropriate operating pressure is set.

In particular, if the shortage is made in accordance with the change in the throttle opening, the change in the throttle opening has a high responsiveness, so that the appropriate operating pressure is set with a better responsiveness.

[Brief description of drawings]

FIG. 1 is a timing chart for explaining the operation of a conventional control device for explaining the problems of the conventional technology.

[Fig. 2]

FIG. 3 is a diagram showing a configuration of a torque sensor used in this embodiment.

FIG. 4 is a block diagram showing the configuration of a control system for an automatic transmission according to this embodiment.

[Figure 5]

FIG. 6 is a diagram for explaining output signals of the sensor of FIG.

7 is a circuit diagram of a hydraulic circuit in the system of FIG.

FIG. 8 is a diagram illustrating a shift line used in the embodiment.

FIG. 9 is a diagram for explaining a mounting position of the sensor of FIG.

FIG. 10 is a flow chart showing the control procedure of the embodiment.

FIG. 11 is a flow chart showing a control procedure of a modified example.

FIG. 12 is a graph showing the characteristics of the correction term.

Claims (5)

[Claims] 1. A torque sensor which is provided on an input shaft of an automatic transmission and picks up a signal representing a torque input to the automatic transmission, and an operating pressure of the transmission is set based on the torque signal from the torque sensor. A hydraulic pressure for an automatic transmission, comprising: an operating pressure setting means; and a correcting means for correcting the operating pressure set by the operating pressure setting means when the rate of change of the torque signal is a predetermined value or more. Control device. 2. The hydraulic control device for an automatic transmission according to claim 1, wherein the correction means corrects the torque signal according to a rate of change of the torque signal. 3. The hydraulic control device for an automatic transmission according to claim 1, further comprising means for detecting an engine load, wherein the correcting means corrects based on the detected rate of change of the engine load. To do. 4. A torque sensor which is provided on an input shaft of an automatic transmission and picks up a signal representing a torque input to the automatic transmission, and an operating pressure of the transmission is set based on the torque signal from the torque sensor. First operating pressure setting means, means for detecting engine load, second operating pressure setting means for setting operating pressure of the transmission based on the detected engine load, and a rate of change of the torque signal is predetermined. When the value is equal to or more than a value, the operating pressure set by the first operating pressure setting means is switched to the operating pressure set by the second operating pressure setting means. Transmission hydraulic control device. 5. A torque sensor which is provided on an input shaft of an automatic transmission and picks up a signal representing a torque input to the automatic transmission, and an operating pressure of the transmission is set based on the torque signal from the torque sensor. First operating pressure setting means, means for detecting engine load, second operating pressure setting means for setting operating pressure of the transmission based on the detected engine load, and change in the detected engine load When the ratio is equal to or higher than a predetermined value, the operating pressure set by the first operating pressure setting means is switched to the operating pressure set by the second operating pressure setting means. Hydraulic control device for automatic transmission.