JP4157408B2 - Hydraulic control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to hydraulic control when a travel range is selected to a power non-transmission range.
[0002]
[Prior art]
Conventionally, the hydraulic pressure of an automatic transmission provided with an accumulator in the circuit connecting the manual valve and the forward / reverse clutch for the purpose of reducing the engagement shock of the forward / reverse clutch when selecting from the power non-transmission range to the travel range when the vehicle is stopped A control device is known (see, for example, Patent Document 1).
[0003]
In this hydraulic control device, by controlling the back pressure of the accumulator according to the line pressure and the throttle opening, for example, at the time of N → D selection, a part of the line pressure supplied from the manual valve is throttled. Depending on the opening, pressure is accumulated in the accumulator pressure accumulator, and a sudden change in hydraulic pressure of the starting clutch is mitigated to suppress the occurrence of a fastening shock.
[0004]
Also, in such a vehicle, when the oil temperature is lower than the predetermined oil temperature, the line pressure is set to the highest pressure regardless of the engine load such as the throttle opening, so that the oil flow is caused by the oil viscosity. It is also known to perform so-called line pressure MAX control that prevents deterioration of responsiveness even if the delay is delayed (see Non-Patent Document 1).
[0005]
[Patent Document 1]
JP-A-7-42823 [0006]
[Non-Patent Document 1]
Maintenance manual (NISSAN full-range electronically controlled automatic transmission document code A261C14 date of issue August 1989) (see page A-37, line pressure control at low temperatures)
[0007]
[Problems to be solved by the invention]
By the way, in the hydraulic control device, when the starting clutch is released, both the starting clutch and the back pressure of the accumulator are discharged from one oil passage to the manual valve. That is, since the exhaust pressures of each other merge in one oil passage, the discharge of hydraulic pressure from the starting clutch tends to be delayed as compared with a configuration in which no accumulator is provided.
[0008]
This delay in oil leakage from the starting clutch does not pose a problem at room temperature, but there is a possibility that oil leakage may be further delayed at a low temperature when the viscosity of the oil is high as compared with that at normal temperature. In addition, when the line pressure MAX control is executed for the hydraulic control device, the accumulator back pressure is set to the maximum pressure at low temperatures, so when the travel range is selected to the power non-transmission range. In addition, there is a problem that the oil accumulated in the accumulator accumulator chamber is exhausted vigorously, and the oil release from the starting clutch is further deteriorated.
[0009]
The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to achieve fastening at low oil temperature in a hydraulic control device for an automatic transmission having an accumulator in a circuit connecting a manual valve and a fastening element. It is to prevent delay of oil draining from the element.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, in the hydraulic control device for an automatic transmission according to claim 1 of the present invention, when the travel range is switched to the power non-transmission range, the line pressure MAX control is prohibited. A control prohibition section is provided.
[0011]
Furthermore , the line pressure MAX control inhibition time is set according to the oil temperature.
[0012]
In the hydraulic control device for an automatic transmission according to claim 2 , the MAX control prohibition is canceled when the detected hydraulic pressure is equal to or lower than a predetermined hydraulic pressure.
[0013]
[Action and effect of the invention]
In the first aspect of the invention, the accumulator back pressure can be set small by prohibiting the line pressure MAX control that sets the line pressure to the maximum pressure when the range is switched from the travel range to the power non-transmission range. As a result, oil drainage from the accumulator is no longer given priority, and it is possible to prevent delays in oil draining from the fastening elements, and power can be reduced in a short time when the travel range is switched to the power non-transmission range. Can be blocked.
[0014]
Further, for example, the oil temperature is low, when the viscous resistance, by setting the inhibition time of the line pressure MAX control longer, the line pressure MAX control inhibition time be set appropriately according to the time of the omission of the oil it can.
[0015]
In the second aspect of the present invention, it is possible to detect the timing at which the hydraulic pressure is released reliably by directly detecting whether or not the hydraulic pressure of the fastening element has been released by the hydraulic pressure detection means, and prohibit the line pressure MAX control. Can be done appropriately.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments will be described below with reference to the drawings. FIG. 1 is a skeleton diagram showing a gear transmission for an automatic transmission according to an embodiment.
1, G1, G2, and G3 are planetary gears, M1, M2 are connecting members, C1, C2, and C3 are clutches, B1, B2, B3, and B4 are brakes, F1, F2, and F3 are one-way clutches, and IN is an input. A shaft (input member), OUT is an output shaft (output member).
[0017]
The first planetary gear G1 is a single pinion type planetary gear having a first sun gear S1, a first ring gear R1, and a first carrier PC1 that supports a pinion that meshes with both the gears S1 and R1.
[0018]
The second planetary gear G2 is a single pinion type planetary gear having a second sun gear S2, a second ring gear R2, and a second carrier PC2 that supports a pinion that meshes with both gears S2 and R2.
[0019]
The third planetary gear G3 is a single pinion type planetary gear having a third sun gear S3, a third ring gear R3, and a third carrier PC3 that supports a pinion that meshes with both the gears S3 and R3.
[0020]
The first connecting member M1 is a member that integrally connects the first carrier PC1 and the third ring gear R3.
[0021]
The second connecting member M2 is a member that integrally connects the second ring gear R2 and the third carrier PC3.
[0022]
The input clutch C1 is a clutch that selectively connects and disconnects the first ring gear R1 and the second ring gear R2.
[0023]
The high & low coast clutch C2 is a clutch that selectively connects and disconnects the second sun gear S2 and the third sun gear S3. The high and low coast clutch C2 is provided with a first one-way clutch F1 in parallel.
[0024]
The direct clutch C3 is a clutch that selectively restrains the third carrier PC3 and the third sun gear S3.
[0025]
The reverse brake B1 is a brake that selectively stops the rotation of the second connecting member M2.
[0026]
The front brake B2 is a brake that selectively stops the rotation of the first sun gear S1. The second brake B2 is provided with a second one-way clutch F2 in parallel.
[0027]
The low coast brake B3 is a brake that selectively stops the rotation of the second sun gear S2. The third brake B3 is provided with a forward brake B4 and a third one-way clutch F3 (B4 and F3 are arranged in series with each other) in parallel.
[0028]
The input shaft IN is connected to the first ring gear R1 and inputs engine rotational driving force via a torque converter (not shown).
[0029]
The output shaft OUT is connected to the second carrier PC2 and transmits the output rotational driving force to driving wheels via a final gear or the like not shown.
[0030]
Each of the clutches C1, C2, C3 and the brakes B1, B2, B3, B4 has a control valve unit 1 (to be described later) for generating an engagement pressure and a release pressure at each shift stage and a control device (not shown) for controlling the control valve unit 1. It is connected.
[0031]
FIG. 2 is a diagram illustrating a fastening operation table in the gear transmission for an automatic transmission according to the embodiment.
In FIG. 2, Δ is a state related to torque transmission at power-on, C is a state related to torque transmission at coast, ● is a state where hydraulic pressure is supplied to the fastening element but has no effect on output, ○) is the state that is engaged in overrun mode, (○) * is the state that is engaged when selected, and then released when not in overrun mode, (○) ** is the state that is engaged only at high load, and ○ is the state that is engaged Indicates. The overrun mode refers to the manual shift mode when the range position of a select lever (not shown) selects 2 range or 1 range, or when the automatic transmission has an automatic shift mode and a manual shift mode. The case where is selected is collectively referred to as overrun mode. That is, in the automatic transmission according to the embodiment of the present invention, when the select lever is switched from the D range to the N range, the oil normally supplied to the forward brake B4 and the front brake B2 is discharged. It becomes.
[0032]
FIG. 3 is a system diagram showing a hydraulic control device for an automatic transmission according to the present invention. The control unit 20 receives a vehicle speed signal from the vehicle speed sensor 21, an engine speed signal from the engine speed sensor 22, an oil temperature signal from the oil temperature sensor 23, and an inhibitor signal from the inhibitor switch 24.
[0033]
Based on these sensor signals, the control unit 20 executes fastening / release control of various fastening elements provided in the automatic transmission to perform shift control.
[0034]
Next, main circuit portions in the control valve unit 30 will be described. In the present embodiment, a forward fastening element will be described, but it may be a fastening element that requires fastening during traveling (for example, a backward fastening element), and is not particularly limited.
FIG. 4 is a main circuit diagram of the control valve unit. The hydraulic pressure discharged from the oil pump unit 13 is regulated by the pressure regulator valve 16 and outputs a line pressure. This line pressure is supplied to the input port 10 of the manual valve 7. The line pressure is regulated by the accumulator control valve 17 and input to the back pressure port 15 of the accumulator 14. The pressure regulator valve 16 and the accumulation control valve 17 are controlled by a line pressure linear solenoid 18.
[0035]
When the driver selects the D range, the manual valve 7 outputs the line pressure from the output port 101. The line pressure output from the manual valve 7 is supplied to the oil passage 101 → the oil passage 106 → the oil passage 107 and the oil passage 108. Then, the fastening pressure is supplied to the forward brake B4 and the accumulator 14 is accumulated. The accumulator 14 is back pressure controlled by an accumulator control valve 17, and the fastening shock is relieved by this back pressure control.
Here, the flow of oil in the oil passage 101 → the oil passage 106 will be described.
(When forward brake is engaged)
When the forward brake B4 is engaged, oil is supplied from the manual valve 7 to the forward brake B4 and the accumulator 14. At this time, when the oil passage 101 supplies the oil passage 106, the following three routes are followed.
(1) Oil path 101 → oil path 102 → orifice 102a → one-way valve 102b → oil path 105 → oil path 113 → orifice 113a → oil path 106.
(2) Oil passage 101 → oil passage 103 → orifice 103a → oil passage 113 → orifice 113a → oil passage 106.
(3) Oil passage 101 → oil passage 104 → orifice 104a → one-way valve 104b → oil passage 106.
[0037]
(When forward brake is released)
When the forward brake B4 is released, the oil of the forward brake B4 and the accumulator 14 is drained. At this time, when draining from the oil passage 106 to the oil passage 101, the following two routes are followed.
(1) Oil path 106 → oil path 112 → orifice 112a → one-way valve 112b → oil path 105 → orifice 103a → oil path 103 → oil path 101.
(2) Oil path 106 → oil path 113 → orifice 113a → orifice 103a → oil path 103 → oil path 101.
[0038]
(First embodiment)
A first embodiment will be described based on the flowchart of FIG. In the present embodiment, in normal line pressure control, for example, as shown in a throttle opening-line pressure map in FIG. 6, the line pressure is set based on the engine load or engine torque. Further, in the line pressure MAX control, in order to eliminate the delay in the operation of the friction element caused by the reduced oil flow speed due to the viscous resistance at low oil temperature (for example, −10 ° C. or less), By always setting the line pressure to the highest pressure regardless of the engine torque, the friction element is operated smoothly. In the line pressure MIN control, the line pressure is always set to the lowest pressure regardless of the engine load or engine torque at low temperatures.
In step S1, the shift signal from the inhibitor switch 24 is input.
In step S2, an oil temperature signal from the oil temperature sensor 23 is input.
[0039]
In step S3, the oil temperature signal to determine whether a predetermined oil temperature T ₀ or less, the process proceeds to step S5 when T ₀ or less, otherwise proceeds to step S4.
[0040]
In step S4, normal line pressure control is executed.
[0041]
In step S5, it is determined whether or not the shift signal is in the travel range in the previous control cycle and in the power non-transmission range such as the P range or N range in the current control cycle. Otherwise, go to step S7.
[0042]
In step S6, line pressure MIN control is executed.
[0043]
In step S7, line pressure MAX control is executed.
[0044]
The said control is demonstrated based on the time chart of FIG. In addition, a continuous line shows a present Example and a dotted line has shown the comparative example. In the comparative example, when the D range is switched to the N range by the driver's operation at time t1, the line pressure MAX control is continuously executed at a predetermined oil temperature T ₀ or less. However, during the line pressure MAX control, the line pressure is set high and the back pressure of the accumulator 14 is also set high, so that the oil in the accumulator 14a of the accumulator 14 is pushed out vigorously and the forward brake B4. Oil drainage from the tank is delayed.
[0045]
On the other hand, in the first embodiment, at time t1, when switched from the D range to the N range by operation of the driver, albeit at a predetermined fluid temperature T ₀ or less, the previous range position is D range, the current Since the range position is the N range, the line pressure MIN control is executed. For this reason, it becomes possible to set the accumulator back pressure small, and the oil in the pressure accumulation chamber 14a of the accumulator 14 is prevented from being discharged preferentially. As a result, the oil withdrawal delay of the forward brake B4 can be prevented preferentially, and the power can be cut off in a short time when the traveling range is switched to the power non-transmission range.
[0046]
(Second embodiment)
A second embodiment will be described. FIG. 8 is a flowchart showing the line pressure control at the time of selection from the travel range to the power non-transmission range. Since the basic control contents are the same as those in the first embodiment, only different steps will be described.
[0047]
In step S61, it is determined whether or not the predetermined prohibition time set by the oil temperature-prohibition time map shown in FIG. 9 has elapsed. When the predetermined time has elapsed, the process proceeds to step S7, and the line pressure MAX control is executed.
[0048]
The contents of the control will be described based on the time chart of FIG. When switching from the D range to the N range by the driver's operation at time t1, the prohibition time T1 is set from the oil temperature-prohibition time map shown in FIG. At the same time, the timer counts up. When the timer value reaches the prohibition time T1 at time t2, it is determined that the oil from the forward brake B4 has been completely removed, and the process proceeds to line pressure MAX control.
[0049]
That is, an object of the present invention is to prevent the oil in the pressure accumulating chamber 14a of the accumulator 14 from being discharged preferentially. In the case where the oil temperature is low, it is desirable to execute the line pressure MAX control after the oil is removed in consideration of responsiveness. Therefore, by providing a prohibition time corresponding to the oil temperature, executing the line pressure MIN control for the prohibition time corresponding to the viscous resistance, and thereafter executing the line pressure MAX control, the operational effect of the first embodiment is achieved. In addition, it is possible to prevent deterioration of responsiveness at the time of selection from the next power non-transmission range to the travel range.
[0050]
A third embodiment will be described. FIG. 11 is a circuit diagram showing a main circuit. The basic configuration is the same as that of the first embodiment, except that a hydraulic switch 25 that is operated by the hydraulic pressure of the forward brake B4 is provided.
[0051]
FIG. 12 is a flowchart showing the line pressure control at the time of selection from the travel range to the power non-transmission range in the third embodiment. Since the basic control contents are the same as those in the first embodiment, only different steps will be described.
[0052]
In step S62, it is determined whether or not the hydraulic switch 25 is ON. If it is ON, the process returns to step S6 to continue the line pressure MIN control, and if it is OFF, the process proceeds to step S7 to execute the normal line pressure control.
[0053]
That is, while the oil pressure switch 25 is ON, oil still remains in the forward brake B4, so that the oil in the accumulator 14a of the accumulator 14 is prevented from being discharged preferentially by continuing the line pressure MIN control. When it is determined that the switch 25 is OFF, that is, the oil of the forward brake B4 has been drained, the line pressure MAX control is executed. As a result, in addition to the operational effects of the first embodiment, it is possible to switch to normal control immediately after the oil of the forward brake B4 is drained, and further to prevent deterioration of responsiveness at the next N → D selection. it can.
[0054]
In the third embodiment, the hydraulic switch 25 is provided. However, in the hydraulic control apparatus for an automatic transmission as shown in Japanese Patent Laid-Open No. 2001-50382, which has a hydraulic switch in the oil passage that originally supplies the clutch pressure. By diverting this hydraulic switch, the present invention can be achieved without adding the number of parts.
[0055]
(Other embodiments)
As mentioned above, although embodiment which implement | achieves this invention was described, the specific structure of this invention is not limited to this embodiment, For example, it is also possible to set it as the structure which made the forward / reverse engaging element the reverse brake. Good.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a gear transmission for an automatic transmission.
FIG. 2 is a diagram illustrating a fastening operation table in a gear transmission for an automatic transmission.
FIG. 3 is a system diagram illustrating a hydraulic control device for an automatic transmission according to the embodiment.
FIG. 4 is a circuit diagram showing a main circuit of the first embodiment.
FIG. 5 is a flowchart showing line pressure control at the time of selection from a travel range to a power non-transmission range in the first embodiment.
FIG. 6 is a line pressure-throttle opening degree map during normal control in the first embodiment.
FIG. 7 is a time chart at the time of D → N selection in the first embodiment.
FIG. 8 is a flowchart showing line pressure control at the time of selection from a travel range to a power non-transmission range in the second embodiment.
FIG. 9 is a map showing the relationship between prohibited time and oil temperature in the second embodiment.
FIG. 10 is a time chart at the time of D → N selection in the second embodiment.
FIG. 11 is a circuit diagram showing a main circuit of a third embodiment.
FIG. 12 is a flowchart showing line pressure control at the time of selection from a travel range to a power non-transmission range in the third embodiment.
[Explanation of symbols]
B1-B4 Brake F1-F3 One-way clutch G1-G3 Planetary gear M1, M2 Connection member R1-R3 Ring gear PC1-PC3 Carrier S1-S3 Sun gear 7 Manual valve 10 Input port 13 Oil pump unit 14 Accumulator 15 Back pressure port 16 Pressure regulator Valve 17 Accumulation control valve 18 Line pressure duty solenoid 19 Forward brake 20 Control unit 21 Vehicle speed sensor 22 Engine speed sensor 23 Oil temperature sensor 24 Inhibitor switch 25 Hydraulic switch

Claims (2)

An accumulator provided on an oil passage connecting a manual valve and a fastening element to be fastened in the traveling range;
A line pressure MAX control means for setting the line pressure and the accumulator back pressure to a maximum pressure when the oil temperature is equal to or lower than a predetermined oil temperature;
In a hydraulic control device for an automatic transmission equipped with
When the line pressure MAX control means is switched from the travel range to the power non-transmission range, a MAX control prohibition unit for prohibiting the line pressure MAX control is provided ,
A hydraulic control device for an automatic transmission, wherein the line pressure MAX control means is provided with a prohibition time setting unit for setting the line pressure MAX control prohibition time according to an oil temperature . The hydraulic control device for an automatic transmission according to claim 1,
Providing a hydraulic pressure detection means for detecting the hydraulic pressure of the fastening element;
The MAX control prohibiting unit releases the MAX control prohibition when the detected hydraulic pressure is equal to or lower than a predetermined hydraulic pressure .

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