JP4034953B2 - 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.
[0002]
[Prior art]
The automatic transmission includes a rotating element including a planetary gear set in the speed change mechanism, and also includes an engaging element such as a clutch or a brake for engaging and releasing between the rotating elements. Each of the fastening elements is operated by hydraulic pressure, and a plurality of shift stages are obtained by fastening and releasing the fastening elements in a predetermined combination.
FIG. 6 shows an example of supplying hydraulic pressure to the clutch which is the engaging element.
A line pressure using an oil pump (not shown) as a generation source is regulated by a pressure regulating valve 10 controlled by a solenoid (SOL) 11 and supplied to the clutch 40.
[0003]
The pressure regulating valve 10 receives the control pressure from the solenoid 11 at one control end, feeds back the output pressure to the other control end, and maintains the output pressure corresponding to the control pressure.
A hydraulic switch (SW) 13 is provided in the oil passage 42 between the pressure regulating valve 10 and the clutch 40, and detects the operation timing of the clutch 40 from the clutch pressure when the clutch 40 is filled or drained. With this operation timing, hydraulic control between the related fastening elements is performed so as to realize a quick and smooth shift.
[0004]
[Problems to be solved by the invention]
Here, in the shift to the gear position at which the clutch 40 is engaged, the pressure regulating valve 10 gives a control pressure for instructing the maximum command pressure from the solenoid 11 in order to maintain the engaged state at the time of non-shift after the completion of the shift. The output pressure from the pressure regulating valve 10 to the clutch 40 is the same as the line pressure.
That is, at this time, the line pressure is not reduced and supplied to the clutch 40 as it is.
As shown in FIG. 7, the pressure regulating valve 10 is provided with a spool 35 in a valve hole 31 including an input port 32, an output port 33, and a drain port 34 so as to allow a stroke. Line pressure is supplied to the input port 32, and the output port 33 is connected to the clutch 40.
[0005]
At the time of so-called pressure regulation where the command pressure is lower than the line pressure, the control pressure (SOL pressure) from the solenoid 11 is small, and the land 36 of the spool 35 forms a throttle S at the input port 32 as shown in FIG. Thus, the output pressure reduced thereby is supplied from the output port 33 to the clutch 40.
On the other hand, when the value of the command pressure is higher than the line pressure, and therefore the control pressure from the solenoid 11 is also large, the input port 32 is not throttled by the land 36 as shown in FIG. 32 and the output port 33 are in a completely connected state.
For this reason, if there is hydraulic vibration generated in the line pressure due to the structure of the oil pump, the hydraulic vibration is applied to the hydraulic switch 13 as it is.
Even if the effective pressure of the hydraulic vibration is low, if the instantaneous value exceeds the allowable pressure of the hydraulic switch 13 and acts at a high frequency, the durability of the hydraulic switch 13 is significantly impaired.
[0006]
Further, in the case of an oil pump that rotates in proportion to the engine speed, as shown in FIG. 8, when the engine speed increases, the oil pump speed increases and the amplitude width of the hydraulic vibration of the line pressure increases, so that the durability of the hydraulic switch Remarkably deteriorates sex.
[0007]
Accordingly, in view of the above problems, the present invention provides a hydraulic control device for an automatic transmission that improves the durability of a hydraulic switch that detects the hydraulic pressure of a fastening element so that the hydraulic switch is not affected by the hydraulic vibration of the line pressure. The purpose is to provide.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is an automatic transmission comprising a plurality of fastening elements that are hydraulically operated with a plurality of rotating elements, and configured to obtain a plurality of shift stages by a combination of fastening and releasing of the fastening elements. , A hydraulic control device for an automatic transmission, comprising: a pressure regulating valve that regulates the line pressure and outputs the regulated hydraulic pressure to a hydraulic pressure supply path of a predetermined fastening element; and a hydraulic switch that operates according to the hydraulic pressure of the hydraulic pressure supply path The switching valve provided in the hydraulic pressure supply path and a pressure reducing valve for reducing the line pressure. The switching valve reduces the hydraulic pressure reduced by the pressure reducing valve according to the hydraulic pressure of the hydraulic pressure supply path output from the pressure regulating valve. It is assumed that it outputs to the hydraulic switch.
[0009]
According to the second aspect of the present invention, the pressure regulating valve is controlled by a solenoid, and a pilot pressure that is an input pressure of the solenoid is set to a hydraulic pressure that acts on the hydraulic switch via the switching valve.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described by way of examples.
FIG. 1 shows an example of a gear train of an automatic transmission to which the hydraulic control device of the embodiment is applied.
The transmission mechanism 7 includes a first planetary gear set Gl and a second planetary gear set G2 coaxially with the engine output shaft ENG.
A torque converter T / C is interposed between the engine output shaft ENG and the transmission input shaft IN, and a lockup clutch L / U is attached to the torque converter T / C. A first planetary gear set G1 and a second planetary gear set G2 are interposed between the transmission input shaft IN and the transmission output shaft OUT. The first planetary gear set G1 is a simple planetary gear set including a first pinion gear P1, a first carrier C1, a first sun gear S1, and a first ring gear R1, and the second planetary gear set G2 is a second pinion gear P2, This is a simple planetary gear set comprising a two carrier C2, a second sun gear S2, and a second ring gear R2.
[0011]
The transmission input shaft IN and the second sun gear S2 are directly connected. A reverse clutch R / C is provided in the middle of the member connecting the transmission input shaft IN and the second sun gear S1, and the member can be fixed to the case. 2-4 brake 2-4 / B with a multi-plate brake structure is provided. A high clutch H / C is provided in the middle of the member connecting the transmission input shaft IN and the first carrier C1. A low clutch L / C is provided in the middle of the member connecting the first carrier C1 and the second ring gear R2, and a low and reverse brake L & R / B having a multi-plate brake structure that enables the member to be fixed to the case. A one-way clutch OWC is provided in parallel. The first ring gear R1 and the second carrier C2 are coupled, and the transmission output shaft OUT is coupled to the second carrier C2.
[0012]
FIG. 2 is a diagram showing a clutch engagement logic table in each gear stage of the reverse range (hereinafter R range) and the drive range (hereinafter D range). (The circle indicates the fastened state, and the cross indicates the open state.)
[0013]
The low clutch L / C is engaged when the D range is first speed, the low clutch L / C and the 2-4 brake 2-4 / B are engaged when the D range is second speed, and the low clutch L / C is high when the D range is third speed. The clutch H / C is engaged, and the high clutch H / C and the 2-4 brake 2-4 / B are engaged at the fourth speed in the D range. During the R range, the reverse clutch R / C and the low and reverse clutch L & R / B are engaged.
[0014]
FIG. 3 is a diagram showing a shift control system of an automatic transmission to which the present invention is applied as an embodiment.
A line pressure using an oil pump (not shown) as a generation source is supplied to the manual valve 2 through the line pressure oil passage 1. The manual valve 2 is a valve that can be switched by a select operation. In the D range, the line pressure oil passage 1 and the D range pressure oil passage 3 are connected, and in the R range, the line pressure oil passage 1 and the R range pressure oil passage 4 are connected. Is done.
[0015]
The pressure reducing valve 5 is connected to the pilot pressure oil passage 6 by controlling the line pressure from the line pressure oil passage 1 to a constant pilot pressure.
[0016]
Pressure regulating valves 8, 10a are respectively provided in the oil passages connected from the D range hydraulic passage 3 to the low clutch L / C and the high clutch H / C. The pressure regulating valves 8 and 10a are controlled by duty control type solenoids 9 and 11a that operate according to a command from the AT control unit 24, and generate a low clutch pressure and a high clutch pressure from the D range pressure, respectively.
[0017]
A first fail-safe valve 25 and a pressure regulating valve 10b that use the output pressure from the second fail-safe valve 26 as an operation signal pressure are provided in the oil path that leads from the D range hydraulic path 3 to the 2-4 brake 2-4 / B. It has been. The pressure regulating valve 10b is controlled by a duty control type solenoid 11b that operates according to a command from the AT control unit 24, and generates 2-4 brake pressure from the D range pressure.
A third fail-safe valve 27, a fourth fail-safe valve 28, and a pressure regulating valve 10c are provided in the oil path that leads from the line pressure oil path 1 to the low and reverse brake L & R / B. The pressure regulating valve 10c is controlled by a duty control type solenoid 11c that operates according to a command from the AT control unit 24, and generates a low and reverse brake pressure from the line pressure.
The pressure regulating valve 8 generates a low clutch pressure from the line pressure and outputs it to the low clutch L / C.
[0019]
A switching valve 30 (30a, 30b, 30c) is provided in each oil passage connected to the corresponding clutch or brake from each pressure regulating valve 10 (10a, 10b, 10c), and the switching valve 30 (30a, 30b, 30c). The hydraulic switch 13 (13a, 13b, 13c) is connected to each. Pilot pressure is supplied from the pilot pressure oil passage 6 to the switching valve 30 (30a, 30b, 30c). When hydraulic pressure is supplied to the corresponding clutch or brake from each pressure regulating valve 10 (10a, 10b, 10c), the hydraulic pressure acts on the switching valve 30 (30a, 30b, 30c), and the switching valve 30 (30a, 30b, 30c), the pilot pressure is output to the hydraulic switch 13 (13a, 13b, 13c), and the hydraulic switch 13 (13a, 13b, 13c) is activated.
[0020]
The ON / OFF type pressure control solenoid 22 switches the line pressure between the high pressure and the low pressure.
The duty control type lockup solenoid 23 controls the engagement and disengagement of the lockup clutch.
[0021]
The AT control unit 24 performs various control calculation processes including shift control based on the input information, and outputs solenoid drive currents to the solenoids 9, 11a, 11b, 11c, 22, and 23 according to the processing results.
[0022]
A first failsafe valve 25 and a second failsafe valve 26 are provided on the input side of the pressure regulating valve 10b of the 2-4 brake 2-4 / B.
The first failsafe valve 25 uses the low clutch pressure PL / C as an operation signal pressure. The second failsafe valve 26 uses the high clutch pressure as an operation signal pressure.
[0023]
At the third speed when the low clutch pressure and the high clutch pressure are generated simultaneously, the high clutch pressure is applied to the second failsafe valve 26, whereby the low clutch pressure PL / C is applied to the first failsafe valve 25. Forcibly drain the 2-4 brake pressure.
[0024]
A third failsafe valve 27 and a fourth failsafe valve 28 are provided on the input side of the pressure regulating valve 10c of the low and reverse brake L & R / B.
The third failsafe valve 27 uses the high clutch pressure as the operation signal pressure, and the strategy 4 failsafe valve 28 uses the 2-4 brake pressure as the operation signal pressure, and either the high clutch pressure or the 2-4 brake pressure or both. The low and reverse brake pressure is drained at the second, third, and fourth speeds when the hydraulic pressure is generated.
[0025]
The AT control unit 24 receives switch signals indicating the hydraulic states of the respective fastening elements from the hydraulic switches 13a, 13b, and 13c. When shifting, the solenoids 11a, 11b, Command signals are output to 11c and 9.
[0026]
FIG. 4 shows the structure of the switching valve 30a of the present invention.
The pressure reducing valve 5 reduces the line pressure to be constant and reduces the amplitude width of the hydraulic vibration. Further, the line pressure is reduced and output as a pilot pressure to the switching valve 30a. The switching valve 30a is composed of a valve body 53, a spring 55, and a spool 54. The outer diameter of the land 59 is larger than the outer diameter of the land 58, and an oil passage leading from the switching valve 30a to the hydraulic switch 13a branches off to the port 52. Provide a connecting oilway. The spool 54 is set so that the hydraulic pressure of the port 52 acts on the end face of the land 59 when the port 50 and the port 53 are in a position where they slightly communicate with each other. The high clutch pressure is input from the port 51 and the pilot pressure is input from the port 50 to the switching valve 30a. When the clutch is engaged, the high clutch pressure rises, whereby one end of the spool 54 is pushed and the spool 54 moves, and the pilot pressure that has been cut off by the land 60 is output to the hydraulic switch 13a and the port 52, and the hydraulic switch is activated. . Since the outer diameter of the land 59 is larger than the outer diameter of the land 58, the pilot pressure input from the port 52 pushes the end surface of the land 59, and the spool 54 starts from a position where the port 50 and the port 53 are slightly communicated with each other. Immediately move to the position of the switching valve 30a shown on the right side of the figure.
The hydraulic switch 13a operates at a predetermined hydraulic pressure that is equal to or lower than the pilot pressure. When the clutch is released, the hydraulic pressure acting on the hydraulic switch 13a is drained from the drain ports 56 and 57.
The same applies to the other switching valves 30b and 30c.
[0027]
The present embodiment is configured as described above, and the hydraulic pressure acting on the hydraulic switches 13a, 13b, and 13c is changed to the hydraulic pressure obtained by reducing the line pressure to the pilot pressure by the pressure reducing valve 5, as shown in FIG. Thus, even if there is a large hydraulic vibration such as the discharge pulsation of the oil pump in the line pressure, the transmission of the hydraulic vibration to the hydraulic switch 13 (13a, 13b, 13c) is greatly attenuated through the pressure reducing valve 5. As a result, the amplitude width of the hydraulic vibration is reduced as shown in FIG. As a result, the maximum value of the amplitude width of the hydraulic vibration does not exceed the allowable pressure of the hydraulic switch 13 (13a, 13b, 13c) in the oil passage between the hydraulic switch 13 (13a, 13b, 13c) and the hydraulic pressure. The durability of the switch 13 (13a, 13b, 13c) is improved.
[0028]
【The invention's effect】
According to the first aspect of the present invention, the hydraulic pressure acting on the hydraulic switch is set as the output pressure from the pressure reducing valve, so that even if the line pressure has the hydraulic vibration, the hydraulic pressure in which the hydraulic vibration is attenuated by the pressure reducing valve is reduced. Act on.
Since the hydraulic pressure with the reduced amplitude of the hydraulic vibration acts on the hydraulic switch, it prevents the instantaneous value of the hydraulic vibration from exceeding the allowable pressure of the hydraulic switch and prevents large pressure from being applied to the hydraulic switch, and the durability of the hydraulic switch There are no restrictions.
[0029]
According to the invention described in claim 2, the structure of the hydraulic control device is simplified by using the pilot pressure as the hydraulic pressure acting on the hydraulic switch via the switching valve.
[Brief description of the drawings]
FIG. 1 is a diagram showing a speed change mechanism of an automatic transmission according to an embodiment of the present invention.
FIG. 2 is a diagram showing a combination of fastening and releasing of fastening elements.
FIG. 3 is a diagram showing a hydraulic control system in the embodiment.
FIG. 4 is a view showing a structure of a switching valve of the present invention.
FIG. 5 is a diagram showing hydraulic vibrations of line pressure and pilot pressure.
FIG. 6 is a diagram illustrating an example of supplying hydraulic pressure to a conventional clutch.
FIG. 7 is a diagram showing a basic structure of a pressure regulating valve.
FIG. 8 is a diagram showing the relationship between hydraulic vibration of line pressure and engine speed.
[Explanation of symbols]
1 Line pressure oil path 2 Manual valve 3 D range pressure oil path 4 R range pressure oil path 5 Pressure reducing valve 6 Pilot pressure oil path 7 Transmission mechanism 8, 10, 10a, 10b, 10c Pressure regulating valves 9, 11, 11a, 11b, 11c Solenoid 13, 13a, 13b, 13c Hydraulic switch 22 Pressure control solenoid 23 Lock-up solenoid 24 AT control unit 25 First fail safe valve 26 Second fail safe valve 27 Third fail safe valve 28 Fourth fail safe valve 30a, 30b 30c Switching valve 31 Valve hole 32 Input port 33 Output port 34, 56, 57 Drain port 35, 54 Spool 36, 58, 59, 60 Land 40 Clutch 42 Oil passage 50, 51, 52 Port 53 Valve body 55 Spring ENG Engine Output shaft G1 First planetary gear set G2 Second planetary gear set 2-4 / B 2-4 Brake H / C High clutch IN Transmission input shaft L & R / B Low and reverse brake L / C Low clutch OUT Transmission output shaft OWC One-way clutch R / C Reverse clutch

Claims (2)

An automatic transmission that includes a plurality of fastening elements that are hydraulically operated with a plurality of rotating elements, and that is configured to obtain a plurality of shift speeds by a combination of fastening and releasing of the fastening elements. In a hydraulic control device for an automatic transmission, comprising a pressure regulating valve that outputs the hydraulic pressure to a hydraulic pressure supply path of a predetermined fastening element, and a hydraulic switch that operates according to the hydraulic pressure of the hydraulic pressure supply path,
A switching valve provided in the hydraulic pressure supply path;
A pressure reducing valve for reducing the line pressure,
The hydraulic control device for an automatic transmission, wherein the switching valve outputs the hydraulic pressure reduced by the pressure reducing valve to the hydraulic switch in accordance with the hydraulic pressure of the hydraulic pressure supply path output from the pressure regulating valve. 2. The hydraulic control device for an automatic transmission according to claim 1, wherein the pressure regulating valve is controlled by a solenoid, and a pilot pressure which is an input pressure of the solenoid is used as a hydraulic pressure acting on the hydraulic switch via the switching valve. .

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