JP3189216B2 - Hydraulic pressure control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pressure control device for an automatic transmission, and more particularly, to reducing a pre-shock pressure on a friction element in order to reduce a select shock when switching from a neutral range to a travel range. The present invention relates to a hydraulic pressure control device configured to output.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic pressure control device of an automatic transmission for reducing a select shock when switching from a neutral range to a driving range, for example,
Japanese Patent Application Laid-Open No. 3-28571 is known.

[0003] In this conventional device, in an automatic transmission having a plurality of friction elements and a hydraulic pressure supply circuit for supplying a hydraulic pressure to these friction elements, when an automatic transmission is switched from a neutral range to a travel range, it is temporarily stopped. After the working fluid pressure is rapidly increased, the working fluid pressure is suddenly decreased to create a shelf pressure for precharging. This is a configuration in which a capacity adjusting pressure adjusting means for creating a capacity adjusting pressure is provided.

Therefore, in this conventional apparatus, when the working fluid pressure is temporarily sharply increased by the precharge pressure adjusting means when switching from the neutral range to the traveling range,
By rapidly lowering the shelf pressure, preparation for fastening the friction element at the time of starting is quickly performed, and then the friction element is completely fastened by gradually increasing the hydraulic fluid pressure by the capacity adjusting pressure adjusting means. Shock during the operation can be greatly reduced.

[0005]

However, frictional elements of an automatic transmission have "variation" in manufacturing, and
There is also "variation" in the rise of hydraulic pressure due to the effects of oil temperature, engine load and vehicle speed. Then, due to such “variation”, the precharge pressure may not reach the predetermined pressure or may exceed it. Also, if the neutral range time before switching to the driving range is short, the precharge pressure supplied to the friction element to be engaged remains, and the precharge pressure is excessively increased by further supplying the precharge pressure in this state. It may be.

Accordingly, as described above, or becomes excessive precharge pressure, when the insufficient or conversely, in the former case and concluded starting at friction element before completing the precharging, shocks There is a problem that
Conversely, in the latter case, there is a problem that even when the precharge is completed, the preparation for engaging the friction element at the time of starting is not completed, and a time lag occurs before the friction element is engaged.

The present invention has been made in view of the above-mentioned conventional problems, and the time from when the neutral range is switched to the running range to when the starting friction element starts engaging is always constant. Precha
Start at the time of selection even if there are unstable factors that hinder
Of the frictional element during the engagement shock and the
The purpose is to prevent the occurrence of mulag .

[0008]

Accordingly, in the present invention, a correction unit for correcting the precharge pressure so that the time from the switching to the driving range to the start of engagement of the friction element at the time of starting becomes a constant target value. To achieve the above object.

In other words, the hydraulic control apparatus for an automatic transmission according to the present invention, as shown in the claim correspondence diagram of FIG. 1, uses hydraulically operated friction to switch the transmission gear of the automatic transmission by a combination of engagement and release. An element a, a hydraulic pressure supply circuit b having a hydraulic actuator for controlling a hydraulic pressure supplied to the friction element a, and a controller c for controlling driving of the hydraulic actuator based on an input from an input means;
When a signal provided to the controller c and indicating that it is time to switch from the neutral range to the travel range is input, the hydraulic fluid pressure is temporarily increased and then rapidly decreased to make the shelf pressure precharge pressure And a precharge pressure adjusting unit d for producing the automatic transmission, the starting friction element a which is engaged when switching from the neutral range to the driving range as input means of the controller c. The start-time engagement detection means e for detecting the start of engagement of the friction element a ′ is provided in the controller c, and the time from when the range is switched from the neutral range to the travel range until the start of engagement of the friction element a ′ when starting is measured. However, a correction unit f that corrects the magnitude of the precharge pressure so that a predetermined target value is obtained is provided.

The running range refers to a range in which the vehicle can run other than a neutral range such as a so-called drive range, reverse range, or first and second speed range.

It is preferable that the target value is set based on at least one of a hydraulic fluid temperature of the automatic transmission, a gear position at the time of selection, an engine load at the time of selection, and a vehicle speed at the time of selection.

Further, the correction by the correction unit f is such that the engine load at the time of selection is equal to or less than a predetermined value, the vehicle speed at the time of selection is equal to or less than a predetermined value, and the vehicle is in a neutral range before switching to a travel range during a predetermined hydraulic fluid temperature. The correction may be performed when at least one or more correction conditions are satisfied among the correction conditions such that the time is equal to or less than a predetermined value, and may not be performed in other cases.

[0013]

When switching from the neutral range to the driving range, the driving of the hydraulic actuator is controlled by the precharge pressure adjusting section d of the controller c to temporarily reduce the operating hydraulic pressure supplied to the friction element a 'at the time of starting. Then, by rapidly descending to form a precharge pressure, which is a shelf pressure for precharging, the preparation for fastening the friction element a 'at the time of starting is quickly performed. Thereafter, control of the hydraulic actuator, such as gradually increasing the hydraulic pressure, is performed.
When starting, the friction element a 'is completely fastened.

In forming the precharge pressure as described above, the correction unit f of the controller c determines the time from when the neutral range is switched to the traveling range to when the starting frictional element a 'starts engaging. Measurement is performed, and correction control is performed so that the measurement time becomes a preset target value. That is, if the measurement time is longer than the target value, the precharge pressure is increased, and correction for shortening the time is performed. Conversely, if the measurement time is shorter than the target value, the precharge pressure is reduced, Perform correction to increase the time.

As a result, the starting frictional element a 'is engaged in the precharging stage, or conversely, a time lag occurs between the end of the precharging and the start of the starting frictional element a'. Or not.

In the apparatus according to the third aspect of the present invention, the above-described correction control is performed when the hydraulic fluid temperature is, for example, a predetermined low temperature, or when the engine load is equal to or less than a predetermined value when the engine is switched to the traveling range, or when the vehicle speed is reduced. This is performed only when a predetermined correction condition is satisfied, such as when the value is equal to or less than a predetermined value or when the time set as the neutral range before the switching is equal to or less than the predetermined value.

The reference numerals in the description of the operation correspond to those in FIG.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

First, the configuration will be described.

FIG. 2 is a schematic view showing a hydraulic pressure control device for an automatic transmission according to an embodiment of the present invention, wherein AT is an automatic transmission, E is an engine, and the automatic transmission AT has an output of an engine E. A gear train GT whose rotation is input via a torque converter TC is built in.

FIG. 3 is a schematic diagram showing the configuration of the gear train GT. The gear train GT includes a front planetary gear set 2 having a front sun gear 2s, a front pinion gear 2p, a front internal gear 2i, and a front carrier 2c. , Rear sun gear 4s, rear pinion gear 4p, rear internal gear 4i, rear carrier 4
c and the rear planetary gear set 4 provided with tandem arrangement c.

The gear train GT includes a reverse clutch R / C connecting the input shaft IN and the front sun gear 2s, and a high clutch H / C connecting the input shaft IN and the front carrier 2c.
A forward clutch F / C connecting the front carrier 2c and the rear internal gear 4i, a brake band B / B fixing the front sun gear 2s to the housing side,
A friction element such as a low and reverse brake L & R / B for fixing the front carrier 2c to the housing is provided.

Further, a forward one-way clutch F / OC is provided between the forward clutch F / C and the rear internal gear 4i, and a low one-way clutch L / C is provided between the front carrier 2c and the housing. An OC is provided, and an overrun clutch ORC is arranged in parallel with the forward one-way clutch F / OC between the front carrier 2c and the rear internal gear 4i.

Meanwhile, in the gear train GT, as shown in Table 1 below, various frictional elements include a line pressure as a working hydraulic pressure supplied from a hydraulic pressure supply circuit CV provided above the automatic transmission AT. By engaging and disengaging by P _L , various speeds can be obtained.

[0025]

[Table 1] In this table, a circle indicates a fastened state, and a blank indicates an open state.

Therefore, the starting frictional elements that are engaged when the vehicle is switched to the travel range in the claims are the reverse clutch R / C and the low and reverse brakes L & R / B in the reverse gear, and the first speed gear. , The forward clutch F / C and the band brake B / B in the second speed, and the forward clutch F / C and the high clutch H in the third speed.
/ C. When the drive D range is selected, the gear is normally controlled to the first gear, but when a mode different from the normal mode is selected by a snow mode switch (not shown) or the like, the second gear or the second gear is selected. It may be controlled to the third gear.

The forward one-way clutch F / OC is free when the rear internal gear 4i is rotated relative to the front carrier 2c in the forward rotation direction, locked when the rear internal gear 4i is rotated in the reverse rotation direction, and is connected to the low one-way clutch. L / OC is free when the front carrier 2c rotates in the normal rotation direction, and locked when the front carrier 2c rotates in the reverse rotation direction.

The overrun clutch O ·
Although the R / C is not shown in Table 1, by engaging the overrun clutch ORC, the function of the forward one-way clutch F / OC is eliminated and the engine brake is operated. Has become.

The stop supply and the supply of the line pressure P _L and the line pressure P _L for actuating the friction element as described above,
The control is performed by the hydraulic pressure supply circuit CV, and a part of valves (not shown) in the hydraulic pressure supply circuit CV is controlled by an A / T control unit (controller) 10 and solenoids 11 to 15 shown in FIG. Is done. That is, the A / T control unit 10 includes, as input means, an inhibitor switch 21 including a one-range switch, a two-range switch, a D-range switch, a P-range switch, and an R-range switch; a vehicle speed sensor 22; , A turbine sensor 24 for detecting the number of rotations of the turbine of the torque converter TC, and an idle switch 31, a full throttle switch 32, a throttle sensor 33, and an ECC control unit 30 for controlling the driving of the engine E. A signal from the engine speed sensor 34 is input. Then, based on these signals, the drive of the line pressure solenoid (hydraulic actuator) 11, the lock-up solenoid 12, the first shift solenoid 13, the second shift solenoid 14, and the timing solenoid 15 is controlled. Since the configuration of the hydraulic pressure supply circuit CV is well known, the description thereof will be omitted.

Then, as shown in Table 2 below, each shift speed can be obtained by switching ON / OFF of the first and second shift solenoids 13 and 14.

[0031]

[Table 2] The switching of the first and second shift solenoids 13 and 14 by the A / T control unit 10 is as follows.
It is determined based on the throttle opening obtained from the throttle sensor 33, the vehicle speed signal obtained from the vehicle speed sensor 22, and the like. For example, the shift is controlled according to a shift schedule determined by the vehicle speed and the throttle opening shown in FIG. .

In this embodiment, the A / T control unit 10 changes the neutral (N) range to the drive range [drive (D) range, third speed (3)].
Range, second speed (2) range, first speed (1) range, reverse (R) range], the line pressure control at the start of traveling is performed.

The running start line pressure control will be described with reference to the flowchart of FIG. The control shown in this flowchart is repeatedly performed every 10 msec.

Step 101 is a step of judging whether or not the range is the N range.

Step 102 is a step for judging whether or not the difference between the turbine speed Ntc in the N range and the current turbine speed Nt has become a predetermined value K or more.
The process proceeds to step 103 in S, and proceeds to step 105 in NO.

Step 103 is a start engagement flag F.
_This is the step of changing ₁ to 1.

Step 104 is a step of setting the learning end flag F ₂ to 0.

Step 105 is a step for determining whether or not the engagement flag F ₁ is 1;
07, and proceeds to step 106 with NO.

Step 106 is a process for measuring the fastening start time T
_In the step of measuring _S , 1 (= 10 msec) is added each time this step is repeated.

Step 107 is a step of measuring the time ( select control time) T from the start of the control at the time of selection, which is the control performed when the range is switched from the N range to the travel range. In each process, 1 (10 msec) is added.

Step 108 is a step of selecting a predetermined precharge time T ₁ in which a select control time T is set in advance.
In the step of determining whether or not the above has elapsed, if YES, proceed to step 119, and if NO, proceed to step 109. Here, it will be described. The pre-charge time T ₁ and the pre-charge pressure P _ch, in this embodiment, as in the prior art, when switching the select lever from the N range to the running range such as D range, FIG. as shown in 6, it is rapidly increased line pressure, so that to make the pre-charge pressure (shelf pressure) P _ch by suddenly lowering the line pressure after a predetermined time has elapsed, to quickly fastening preparation of the starting time of the frictional elements . It referred to as pre-charge time T ₁ is herein a time which forms the pre-charge pressure P _ch.

Incidentally, as shown in Table 1 above,
When the range is switched from the N range to the D range, the forward clutch F / C is basically engaged to set the first speed,
When switching from N range to R range, reverse clutch R / C and low & reverse clutch L & R / C
When the two ranges are selected, the forward clutch F / C and the band brake B / B are engaged, and a precharge pressure _Pch and an engagement pressure as shown in FIG. 6 are supplied to these friction elements. You.

Step 109 is a step of performing processing for calculating precharge pressure data.

Step 110 is a step for performing processing so that the line pressure P _L forms the precharge pressure P _ch .

Step 111 is a step of setting the engagement flag F ₁ to 0.

[0046] Step 112, in determining whether a learning completion flag F ₂ is zero, the process proceeds to step 113 in YES, and the flow proceeds to step 118 if NO.

Step 113 is a step for determining whether or not a learning condition is satisfied. In the present embodiment, the learning condition is that the oil temperature is equal to or lower than a predetermined temperature and the engine load at the time of selection is equal to or lower than a predetermined value. Certain that the vehicle speed at the time of selection is equal to or lower than a predetermined value.

Step 114 is a step of comparing the target time T ₀ with the measured engagement start time T _S , where T ₀ > T _S.
Then, the process proceeds to Step 115, and if T ₀ <T _S , Step 1
The program proceeds to step S16, and if T ₀ = T _S , the program proceeds to step 117.

Step 115 is a step of reducing the precharge pressure P _ch by a predetermined pressure (ΔP _ch ).

Step 116 is a step of increasing the precharge pressure P _ch by a predetermined pressure (ΔP _ch ).

Step 117 is a step in which the learning end flag F _{2 is set} to 1.

Step 118 is a step of performing processing for controlling the line pressure P _L to a normal line pressure.

Step 119 is a step for judging whether or not the starting friction element has completed the engagement. If YES, the process proceeds to step 118, and if NO, the process proceeds to step 120. This determination is made based on whether or not the processing of the next step 120 has been performed.

Step 120 is a step of controlling the line pressure P _L to the engagement pressure Pa. This engagement pressure control is performed until the starting friction element is completely engaged. The fastening pressure Pa is a hydraulic pressure for fastening the friction element when starting. In addition, this fastening pressure control is similar to the prior art,
You may make it increase gradually from a low pressure.

Next, the operation of the embodiment will be described.

[0056] from the N range, when a selection of the running range such as D range, at first, controls the line pressure P _L to form a pre-charge pressure P _ch (Step 11
0). The precharge pressure P _ch ready fastening preparation of the starting time of the friction element.

Then, the set precharge time T ₁
Has passed, the line pressure P is adjusted so as to form the fastening pressure Pa.
_L is controlled (step 119 → 120). In this way, the starting frictional element is started to be fastened. In the present embodiment, the time from when the travel range selection operation is performed to when the starting time frictional element is started to be fastened, that is, the measured fastening start time Measure T _S (Step 105 → 10)
6). Note that whether starting time frictional element starts to fastening, turbine speed N _t is determined by whether or not lowered by a predetermined rotational speed than the rotational speed N _tc of the N range (Step 10
2). Therefore, the start-time engagement detection means referred to in the claims is constituted by the turbine sensor 24 and a part of the A / T control unit 10 that makes a determination in step 102.

[0058] When the starting time of friction element has completed fastening the above, returning the line pressure P _L to the normal line pressure (step 118). Of while performing the above control, the state of change of the turbine speed and the line pressure P _L shown in FIG.

Incidentally, the above-described precharge pressure P _L
Performs correction as necessary when the N range is selected based on the engagement start time measurement value T _S. That is, as shown in steps 112 to 116, when the N range is selected, the learning conditions (for example, the oil temperature is lower than a predetermined value, the engine load is lower than a predetermined value, and the vehicle speed at the time of selection is lower than a predetermined value) are satisfied. And the measured engagement start time T _S when the travel range was previously selected from the N range and the target time T _{0. If} the engagement start time measured T _S is longer than the target time T ₀ , the precharge pressure Correction is performed to increase P _ch by a predetermined pressure (ΔP), and conversely, if it is short, decrease the precharge pressure P _ch by a predetermined pressure (ΔP).

Accordingly, if the measured engagement start time T _S when the travel range is selected this time is longer than the target time T _{0, the} precharge pressure P _ch formed when the travel range is selected next time is increased. By increasing by ΔP, the occurrence of a time lag in fastening is prevented. Conversely, if the engagement start time measurement value T _S when the travel range is selected this time is shorter than the target time T _{0, the} precharge pressure P _ch formed when the travel range is selected next time is ΔP. It is reduced to prevent the starting frictional element from being engaged at the stage of forming the precharge pressure _Pch . As described above, in the A / T control unit 10, as shown in steps 101 → 102 → 105 → 106, N
A portion for measuring the time from when the range is switched to the traveling range to when the starting friction element starts engaging, and as shown in steps 112 to 116, the precharge pressure P _L
Is equivalent to a correcting unit in the claims.

Incidentally, the corrected precharge pressure P
_If the starting friction element does not start fastening, _ch is carried over as a value to be used for the next fastening (according to steps 104 and 112). The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and any change in the design without departing from the gist of the present invention is also included in the present invention.

For example, the time of the N range before switching to the running range is measured, and the relationship between this time and the residual precharge pressure is stored in advance in the correction unit of the controller (for example, as a map). Based on this, when switching to the travel range, a precharge pressure obtained by subtracting the residual precharge pressure may be applied.

As described above, according to the first aspect of the present invention ,
In the hydraulic pressure control device for an automatic transmission described above , based on the time required from when the range is switched from the N range to the traveling range until the start-time friction element starts engaging, the time is set to a constant target value. Is provided with a correction unit for correcting the precharge pressure, so that it is possible to prevent a shift shock due to excessive precharge pressure and a time lag due to insufficient precharge pressure. Ma
In the hydraulic pressure control device for an automatic transmission according to claim 2,
The target value is the operating fluid temperature of the automatic transmission,
Gear position, engine load during selection,
Set based on at least one of vehicle speed
The target value has been set finely according to the condition of the vehicle.
Supply of pre-charge pressure with high accuracy.
It can be carried out. Therefore, when starting
The time between the occurrence of the friction shock and the completion of the friction
This can further prevent the occurrence of noise. Ma
In the hydraulic pressure control device for an automatic transmission according to claim 3,
The correction of the correction unit is performed during a predetermined operating fluid temperature.
Engine load is lower than specified, vehicle speed at select is predetermined
Hereafter, before switching to the driving range,
Of the correction conditions such that the time of
Is executed when at least one or more correction conditions are satisfied.
To avoid erroneous learning.
Can be stopped.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a hydraulic pressure control device for an automatic transmission according to the present invention.

FIG. 2 is a schematic configuration diagram showing the entire hydraulic pressure control device of the automatic transmission according to the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a gear train of the embodiment device.

FIG. 4 is an explanatory diagram showing a shift schedule used in the embodiment device.

FIG. 5 is a flowchart illustrating a control flow of an A / T control unit of the embodiment device.

FIG. 6 is a characteristic diagram showing changes in turbine speed and line pressure when running control is performed by the embodiment device.

[Explanation of symbols]

 a Friction element a 'Start friction element b Hydraulic pressure supply circuit c Controller d Precharge pressure regulating unit e Start engagement detection means f Correction unit

Claims (3)

(57) [Claims] 1. A hydraulic pressure supply having a hydraulically operated friction element for switching a transmission gear of an automatic transmission by a combination of engagement and release, and a hydraulic actuator for controlling a hydraulic pressure supplied to the friction element. A circuit, a controller that controls the driving of the hydraulic actuator based on an input from the input means, and a signal provided at the controller, which indicates that it is time to switch from the neutral range to the travel range, is temporarily A hydraulic pressure control device for an automatic transmission, comprising: a hydraulic pressure control unit for automatically increasing the working fluid pressure and then suddenly decreasing the hydraulic fluid pressure to produce a shelf pressure precharge pressure. A start-up engagement detecting means for detecting the start of engagement of a start-up friction element that is engaged when switching from the neutral range to the travel range. The controller measures the time from when the range is switched from the neutral range to the traveling range until the start of engagement of the friction element at the time of starting, and measures the magnitude of the precharge pressure so that the measured time becomes a preset target value. A hydraulic pressure control device for an automatic transmission, comprising: a correction unit that corrects the hydraulic pressure. 2. The target value is a value set based on at least one of a hydraulic fluid temperature of the automatic transmission, a gear position at the time of selection, an engine load at the time of selection, and a vehicle speed at the time of selection. The hydraulic pressure control device for an automatic transmission according to claim 1, wherein: 3. The correction of the correction unit is performed during a predetermined hydraulic fluid temperature, when the engine load at the time of selection is equal to or less than a predetermined value, the vehicle speed at the time of selection is equal to or less than a predetermined value, and the neutral range before switching to the travel range. 3. The hydraulic pressure of an automatic transmission according to claim 1, wherein the correction is performed when at least one of the correction conditions is equal to or less than a predetermined value, and is not performed when the correction condition is not satisfied. Control device.