JPH1163187A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device for an automatic transmission in a small size and simply, improve responsiveness at the time of a low- temperature, and improve pressure control accuracy. SOLUTION: A line pressure control valve device is provided with an ECU for outputting a line pressure command value according to a traveling condition of a vehicle, a solenoid valve 8 for converting line pressure into liquid pressure on the basis of the command value of the ECU, and a line pressure control spool valve 1 for regulating line pressure PL on the basis of the liquid pressure outputted from the solenoid valve 8. Line pressure PL is controlled on the basis of the command of the ECU in a low speed stage for advancing, a high speed stage, and a backward advancing stage, and thereby, it is possible to reduce member such as a feed back port of the spool valve 1 arranged beforehand, a signal generating valve for generating a range signal, and an oil passage for directly connecting the signal generating valve and the spool valve 1 to each other. It is also possible to improve pressure control accuracy since the line pressure command value is held by the ECU during engaging or disengaging control of a frictional element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a hydraulic pressure of an automatic transmission mounted on an automobile.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile combines a torque converter and a transmission gear mechanism,
The power transmission path of the transmission gear mechanism is switched by a selective operation of a plurality of friction elements such as a clutch and a brake, so that the speed is automatically shifted to a predetermined speed.
This type of automatic transmission is provided with a liquid pressure control circuit that controls the supply and discharge of the working liquid to and from the liquid pressure chamber of the friction element.

Conventionally, a line pressure, which is a source pressure for controlling an automatic transmission, is based on a range signal guided to a feedback port of a line pressure control valve according to a range by a hydraulic control device as shown in FIG. The range to be controlled was changed over. Japanese Patent Application Laid-Open No. 8-326912 discloses a similar configuration.

[0004]

However, in an automatic transmission using the above-mentioned conventional hydraulic pressure control device, when a shift is performed by a driver operating a shift lever, a mechanical line pressure due to range switching is used. Changes and ECU
(Electrical Control Unit) determines and executes the shift control separately, so that the release and engagement control of the friction element for the shift cannot be performed accurately.
In addition, since the response of the shift control at extremely low temperatures is greatly impaired due to the increase in the viscosity of the hydraulic oil, it is attempted to improve the response by increasing the line pressure, but the maximum pressure is limited by the range. In some cases, the response was not able to be greatly improved because of the operation. Also,
It is necessary to provide a feedback port for inputting a pressure signal for each range to the spool valve for controlling the line pressure, and the spool valve becomes large, and it becomes necessary to provide a signal generating valve for generating a range signal. An oil path for directly connecting the signal generating valve and the spool valve was required, and the hydraulic pressure control device was complicated and large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended for an automatic transmission capable of improving the response at low temperatures and improving the accuracy of pressure control while being small and simple. It is an object to provide a hydraulic control device.

[0006]

According to the hydraulic pressure control device for an automatic transmission according to the first aspect of the present invention, the line pressure control valve device includes: a) a command value of a line pressure according to a running state of the vehicle. Line pressure commanding means for outputting a hydraulic pressure based on a command value of the line pressure commanding means;
c) a pressure regulating valve that regulates the line pressure based on the output hydraulic pressure of the electromagnetic hydraulic pressure control means, and controls the line pressure in the forward low speed, high speed, and reverse stages based on the command value of the line pressure command means. Therefore, members such as a feedback port of a spool valve, a signal generating valve for generating a range signal, and an oil path for directly connecting the signal generating valve and the spool valve, which are conventionally provided, can be reduced. Can be

According to a second aspect of the present invention, there is provided a fluid pressure control device for an automatic transmission, comprising a liquid temperature detecting means for detecting a temperature of the liquid, wherein a detected value of the liquid temperature detecting means is less than a predetermined temperature. In this case, since the line pressure is adjusted to a substantially maximum value, there is no limitation on the maximum pressure depending on the range, and the responsiveness of shifting at low temperatures can be improved. According to the third aspect of the present invention, the line pressure command means maintains the line pressure command value during the engagement or disengagement control of the friction element. Is constant, and the release and engagement control of the friction element can be accurately performed.

According to the hydraulic pressure control apparatus for an automatic transmission according to the fourth aspect of the present invention, the line pressure command value is maintained at the time of a gear shift associated with a manual shift operation. Not happen, release of friction element,
Engagement control can be performed accurately.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail by comparing a comparative example using a conventional technique and an embodiment of the present invention with reference to the drawings. (Comparative Example) FIG. 12 shows a line pressure control valve device of a hydraulic pressure control device for an automatic transmission according to a comparative example using a conventional technique.

1 'is a line pressure control spool valve, 2' is a spring, and 3 'is a line pressure control spool valve.
Indicates a reciprocating cylinder. 4 ', 5', 6 ',
7 'is a port for introducing pressure to the line pressure control spool valve 1', 4 'is a source pressure supply port of a torque converter (not shown), 5' is a line pressure control port, and 6 '
Denotes a drain port, and 7 ′ denotes a line pressure feedback control port, which are connected to external pipes 23 ′, 19 ′ and 22 ′, 21 ′, 20 ′, respectively. Unlike the embodiment described later, the port 24 'is open to the atmosphere.

Reference numerals 51 and 54 denote line pressure control spool valves 1 '.
, An auxiliary spool for applying a force via a spring 2 ′, 51 is referred to as a reverse spool, and 54 is referred to as a forward range spool. 50, 52, 53 are auxiliary spools 51
And 54, a reverse pressure port 50 communicated with a pipe 57. Reference numeral 52 denotes a pilot control port for electronically controlling the line pressure, which corresponds to the port 24 in FIG. Reference numeral 53 denotes a forward range port, which communicates with the pipe 55.

Reference numeral 65 denotes a reverse switching valve, which functions to increase the setting of the line pressure at the time of reverse. 60, 6
Reference numerals 2, 63 and 64 denote ports introduced into the reverse switching valve, respectively, which are connected to pipes 59, 61, 57 and 66, respectively. The pipe 59 outputs the pressure of a manual valve (not shown), and high pressure is introduced only during reverse. The pipe 61 is a drain, and the pipe 66 is a pipe branched from the discharge pipe 11 ′ of the oil pump, and the pressure thereof is the supply pressure of the reverse switching valve 65.

The pressure of the pipe 57 becomes the output pressure of the reverse switching valve 65, and is connected to the reverse pressure port 50 at the left end in FIG. The pipe 67 is a pipe branched from the discharge pipe 11 'of the oil pump. Reference numeral 80 denotes an electromagnetic valve for electronically controlling the line pressure, and outputs a command pressure of the line pressure to the pipe 68 according to an electric command. The pipe 68 branches into a pipe 56 and a pipe 75. The pipe 56 communicates with the port 52 of the forward range spool 54 as described above.

Reference numeral 72 denotes a forward range switching valve for determining the D range, the 2 range and the L range during forward travel. Reference numerals 71, 74, 73, and 78 denote ports, respectively, which are connected to pipes 70, 75, 55, and 79, respectively. The pipe 76 is provided with a drain for the purpose of compensating leakage between ports. The pressure in the pipes 70 and 79 is a signal pressure for distinguishing between the D range, the 2 range and the L range, and the position of the forward range switching valve 72 is switched by the two signal pressures. A spring 77 applies a set load to the forward range switching valve 72.

The pipe 75 communicates with the output pressure of the solenoid valve 80 as described above, and introduces the supply pressure of the forward switching valve 72. The pressure of the pipe 55 becomes the output pressure of the forward range switching valve 72 and is communicated with the port 53 of the forward range spool 54 as described above. Table 1 shows the relationship between the level of the signals on the pipes 70, 79 and 55 and the shift speed in each forward range.

[0016]

[Table 1]

In this comparative example, the setting of the line pressure is changed by determining the range as well as the first time when the input torque to the transmission is large. Next, the operation of the above comparative example will be described. The solenoid valve 80 outputs, for example, a pressure corresponding to the throttle opening to the pipe 68 in response to an electric command from an ECU (not shown), and is introduced into the port 52 through the pipe 56. By the introduced pressure, the forward range spool 54 moves rightward, and presses the line pressure control spool valve 1 ′ rightward via the spring 2 ′.
The hydraulic oil discharged from the pump is guided to a port 5 'through a pipe 11'.

When the line pressure control spool valve 1 'is located to the left (that is, when the pressing force to the right is small),
Drain passage 2 from port 5 'to port 6'
It is discharged to 1 'and from port 5' to port 4 '
To the line pressure (pump discharge pressure or pipe 11 ′, 1).
9 ', 22', 20 'and 58).

However, as described above, when a rightward pressing force is applied, the pipe 2 is moved in accordance with the magnitude of the pressing force.
The amount of oil drained to 1 'or 23' is reduced,
The line pressure control feedback port 7 'stops at a position balanced with the leftward force determined by the product of the line pressure and the area acting from the feedback port. As a result, the line pressure can be controlled by the rightward pressing force. it can.

Further, when the R range is selected, the pipe 59 becomes high pressure, the reverse switching valve 65 moves rightward, the port 64 and the port 63 communicate, the pipe 57 becomes high pressure, and the reverse The high pressure is introduced into the left end port 50 of the spool 51, and the rightward pressing force further increases, thereby increasing the line pressure. In the case of the 2 range and the L range, the forward range switching valve 72 is connected to the pipes 70 and 79 described above.
Port 74 and port 73 communicate with each other, and the output pressure of the solenoid valve 80 increases from 68 to port 5 of the forward range spool 54.
3, the rightward pressing force is increased, and the line pressure is increased.

FIGS. 9, 10 and 11 illustrate the results of the operation according to the comparative example described above using graphs. FIG. 10 shows the solenoid valve 80 according to the throttle opening θth.
Indicates a command value to be input to. Figure 9 shows the value of the line pressure P _L in each range to be controlled based on the electrical command value. By combining FIGS. 9 and 10, characteristics of the line pressure P _L with respect to the throttle opening θth is obtained each range as shown in FIG. 11.

(Embodiment) FIG. 1 is a view showing a line pressure control valve device of a hydraulic pressure control device for an automatic transmission according to an embodiment of the present invention. Reference numeral 1 denotes a line pressure control spool valve as a pressure regulating valve,
2 is a spring, 3 is a line pressure control spool valve inside 1
Indicates a reciprocating cylinder. 4, 5, 6, and 7 are ports for introducing pressure to the line pressure control spool valve 1, 4 is a source pressure supply port of a torque converter (not shown), 5 is a line pressure control port, 6 is a drain port, 7
Indicates a line pressure feedback control port,
The pipes are connected to external pipes 23, 19 and 22, 21, 20, respectively. Reference numeral 24 denotes a pilot control port, in which the spring 2 is included, and a command pressure of line pressure is introduced through the pipe 17.

Numeral 8 denotes an electromagnetic valve as an electromagnetic hydraulic pressure control means for electronically controlling the line pressure. The solenoid valve 8 is connected to the pipe 1 in response to an electric command value from an ECU (not shown) as a line pressure command means.
7, a line pressure command pressure is output. Reference numeral 9 denotes a pressure reducing spool valve that generates the source pressure of the solenoid valve 8 from the line pressure. 25,
27, 27 and 28 are ports for introducing pressure to the pressure reducing spool valve 9. The port 25 communicates with the pipe 16 (drain). Port 26 is open to the atmosphere. The port 27 is connected to the pipe 12. Piping 11, 12,
Reference numeral 18 is connected to a discharge port of an oil pump (not shown), and a flow rate according to the pump rotation speed is supplied. Port 2
Reference numeral 8 denotes a feedback chamber of the pressure reducing spool valve 9,
It is communicated with 4. The pipe 13 is branched into pipes 14 and 15 by the output pressure of the pressure reducing spool valve 9. The pressure of the pipe 15 becomes the supply pressure of the solenoid valve 8. A spring 10 acts on the pressure reducing spool valve 9.

Next, the operation of the above embodiment will be described. The hydraulic oil discharged by the pump is supplied to pipes 11, 18, 1
It is led to the port 5 of the line pressure control spool valve 1 through 9. As in the comparative example shown in FIG. 12, when the line pressure is set to a low pressure, the port 5 communicates with the port 6 and the port 5 communicates with the port 4 to discharge the pump discharge oil. Solenoid valve 8
Outputs a pressure corresponding to a throttle opening and a range to a pipe 17 based on a supply pressure of a pipe 15 based on an electric command value from an ECU (not shown). The pressure is controlled by a line pressure control spool valve in FIG. 1 to the leftmost port 24. With this pressure, the line pressure control spool valve 1 is controlled to a position balanced with the force of the line pressure feedback control port 7 in the same manner as the operation described in the comparative example of FIG.

The pressure reducing spool valve 9 has a function of reducing the pump discharge pressure (line pressure) to a certain pressure, and reduces the pressure of the pipe 12 to a predetermined value by a spring 10. The pressure of the pipe 14 is the same as the reduced pressure (the pressure of the pipe 13), and this pressure is controlled to a constant value in proportion to the force of the spring 10. 2, 3, and 4 are graphs showing operation results of the embodiment of the present invention.

FIG. 3 shows the relationship between the throttle opening θth and the range.
Next, the command value input to the solenoid valve 8 will be shown. Shown in FIG.
Unlike the comparative example, the command value differs depending on the range. FIG.
Is the line pressure P controlled based on this command value._LThe value of the
It shows. P by range_LChange the usage area of
I'm changing. FIG. 4 is obtained by combining FIG. 2 and FIG.
Throttle opening θth and line pressure P _LCharacteristics indicating the relationship with
FIG. 11 is a graph showing the same characteristics as the comparative example shown in FIG.
Can be.

Thus, according to this embodiment, FIG.
In the comparative example shown in FIG. 2, the valve, spool, and oil passage for judging and switching the R range as the reverse stage and the L and L ranges as the forward low speed stage provided in the portion 69 surrounded by the broken line are provided. You can reduce it. Therefore, the total number of valves can be significantly reduced. In the embodiment shown in FIG. 1, since the solenoid valve 8 is shown as a duty valve, the pressure reducing spool valve 9 is provided. However, a linear solenoid valve which outputs a constant pressure regardless of the original pressure is used. If used, the pressure reducing spool valve 9 can also be reduced. In addition, since the oil passage can be simplified with the reduction in the number of valves, the size of the housing including these elements and the size of the entire hydraulic pressure control device can be reduced.

Next, the effect of improving the pressure control accuracy according to the embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 5A, when the driver manually operates the shift lever from the second range to the D range as the high speed stage at time t ₀ , a shift is required based on a shift line of each predetermined range. If it is determined that the speed change is determined, a shift command is sent to the hydraulic control device as shown in FIG. The hydraulic pressure control device executes shift control based on the shift command.

[0029] Specifically, c in FIG. 5), it reduces the pressure applied to the friction element on the release side between times t ₂ from time t ₁ as shown in d), the friction element engagement side Increase the applied pressure. In with between the case of upshift from the time t ₂ as shown in e) of FIG. 5 to time t ₃ which, the turbine speed N _t is the output rotational speed of the torque converter
Decrease.

[0030] was such a conventional art shown in Comparative Example, in the middle of the shift (time t ₀ ~t ₂ in the figure), the change of the line pressure P _L by switching the range, as shown in a) of FIG. 6 Occurs. Since the pressures of c) and d) in FIG. 5 are controlled based on the line pressure, a change in the line pressure affects the control pressure of the frictional element, and high-precision pressure control cannot be realized.

On the other hand, in the configuration of the embodiment of the present invention shown in FIG. 1, the change of the line pressure by changing the range is realized in the form of the change of the command value, and therefore, as shown in FIG. The line pressure P _L can be kept from changing during the operation. After the pressure control of the friction element is completed, the line pressure P
_{Since L} can be changed, pressure control of the friction element during shifting can be realized with high accuracy.

In this embodiment, the replacement of the friction element has been described. However, the present invention can be implemented in a control having a one-way clutch. Further, in this embodiment, the case where the range is switched by the manual shift operation has been described. However, the same effect can be obtained when the gear is changed by changing the throttle opening. Next, FIGS. 7 and 8
The effect of improving the response at low temperatures according to the present embodiment will be described with reference to FIG. In the comparative example according to the prior art shown in FIG. 12, when the range is determined, the maximum value of the line pressure is limited. For example, in the D range, the maximum value of the line pressure is set to a value lower than the maximum value in the R range. I couldn't do that. On the other hand, the embodiment of the present invention shown in FIG. 1 can set the maximum line pressure according to the situation regardless of the range as shown in FIG.

The hydraulic oil used for controlling the hydraulic pressure of an automatic transmission generally has a viscosity about three orders of magnitude greater in a very low temperature environment (eg, -30 ° C.) than in a normal temperature environment (eg, 20 ° C.). The response of the shift at cryogenic temperatures becomes extremely slow due to the increase in the speed. Means for increasing the line pressure can be considered as a method of improving the decrease in responsiveness. However, in the related art as shown in the comparative example, the control range of the line pressure is limited depending on the range, and a sufficient effect cannot be obtained. .

In the embodiment of the present invention, by changing the command value of the ECU, regardless of the range (for example, D
Line pressure P _L (equivalent to the maximum pressure of the R range)
Can be set. In the example shown in FIG. 7, the temperature of the liquid is measured by a liquid temperature detecting means (not shown), and when the temperature is lower than a predetermined value, the line is opened regardless of whether the throttle opening is small or large as shown in FIG. has set pressure P _L to the maximum value exceeding the normal use range of each range.
FIG. 8 is a characteristic diagram showing a change in pressure applied to the friction element on the engagement side when the gear is shifted at an extremely low temperature in the comparative example and the example. In the present embodiment, the responsiveness of the pressure change can be dramatically improved as compared with the comparative example.

It should be noted that the present invention is not limited to the configuration of the embodiment shown in FIG. 1, and its application is not limited to the stepped automatic transmission, but may be applied to a continuously variable automatic transmission. Can also.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a command value from an ECU and a line pressure according to an embodiment of the present invention.

FIG. 3 shows a throttle opening and an ECU according to an embodiment of the present invention.
FIG. 9 is a diagram showing a relationship between command values from the control unit.

FIG. 4 is a diagram showing a relationship between a throttle opening and a line pressure according to the embodiment of the present invention.

FIG. 5 is a diagram showing changes in a range, a shift command, a release pressure, an engagement pressure, and a turbine speed when a range is manually switched in the embodiment of the present invention.

FIG. 6 is a diagram comparing a change in line pressure when the range is switched as in FIG. 5 between a comparative example and an embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a temperature and a line pressure at a plurality of throttle openings according to an embodiment of the present invention.

FIG. 8 is a diagram showing a change in engagement pressure during a shift at an extremely low temperature according to an example of the present invention and a comparative example.

FIG. 9 is a diagram illustrating a relationship between a command value from an ECU and a line pressure according to a comparative example.

FIG. 10 is a diagram showing a relationship between a throttle opening and a command value from an ECU according to a comparative example.

FIG. 11 is a diagram illustrating a relationship between a throttle opening and a line pressure according to a comparative example.

FIG. 12 is a diagram showing a comparative example according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Line pressure control spool valve (pressure regulating valve) 2 Spring 3 Cylinder 4 Source pressure supply port of torque converter 5 Line pressure control port 6 Drain port 7 Feedback control port 8 Solenoid valve (electromagnetic fluid pressure control means) 9 Pressure reducing spool valve 10 Spring P _L line pressure

Claims (4)

[Claims] 1. A line pressure control valve device comprising a liquid pressure control circuit for engaging or disengaging a plurality of friction elements, wherein said liquid pressure control circuit regulates a liquid pressure discharged by a liquid pressure source to a predetermined value. A hydraulic pressure control device for an automatic transmission, comprising: a) a line pressure command means for outputting a command value of a line pressure according to a running state of a vehicle; and b) a line pressure command means. And c) a pressure regulating valve that regulates the line pressure based on the output fluid pressure of the electromagnetic fluid pressure controlling means, and a forward speed low speed stage and a high speed speed forward stage. And a fluid pressure control device for an automatic transmission, wherein the line pressure is controlled at a reverse speed based on a command value of the line pressure command means. 2. The hydraulic pressure control device for an automatic transmission according to claim 1, further comprising: d) a liquid temperature detecting means for detecting a temperature of the liquid, wherein a predetermined value is detected by the liquid temperature detecting means. If below the temperature,
A fluid pressure control device for an automatic transmission, which regulates a line pressure to a substantially maximum value. 3. The hydraulic pressure control device for an automatic transmission according to claim 1, wherein said line pressure command means maintains a line pressure command value during engagement / disengagement control of said friction element. 4. The fluid pressure control device for an automatic transmission according to claim 3, wherein said line pressure command means maintains a line pressure command value during a shift associated with a manual shift operation.