JPH01206141A - Device for controlling line pressure of automatic transmission - Google Patents

Abstract

PURPOSE:To ensure the torque capacity of a friction element necessary for strong engine braking by operating a line pressure increasing means by the control device of an automatic transmission to increase a line pressure at the time of operating an exhaust brake device. CONSTITUTION:As the operation signal of an exhaust brake device 216 is inputted, a control unit 300 changes the duty ratio to a line pressure solenoid 44 to increase the oil pressure of an oil passage 202, increasing the pressure of an oil passage 204 which is regulated by a pressure modifier valve 42 to apply the oil pressure to a pressure regulator valve 40. Thereby, the line pressure of an oil passage 208 is increased and the increased oil pressure is fed to clutches and brakes, etc. Thus, even if a strong engine brake is operated due to the action of the exhaust brake device, the clutches and brakes, etc. of an automatic transmission can surely maintain clamped conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a line pressure control device for an automatic transmission.

(b) Conventional technology As a conventional automatic transmission line pressure control device,
There is one shown in Publication No. 2-62047. In this automatic transmission, the line pressure supplied to friction elements such as clutches basically has a characteristic that changes depending on the throttle opening degree. Since the throttle opening approximately corresponds to the output torque of the engine, the line pressure is set to be higher as the throttle opening is larger.

(c) Problems to be Solved by the Invention However, when the automatic transmission as described above is installed in a vehicle equipped with an exhaust brake device, there is a problem that slipping of the clutch etc. may occur when the exhaust brake device is activated. There is a point. That is, the exhaust brake device increases the engine braking effect, but the engine brake only works when the throttle is fully closed, and in this case, the line pressure is at its lowest. For this reason,
Friction elements such as clutches and brakes run out of capacity,
Slippage occurs. When such slipping of latches, brakes, etc. occurs, the effect of engine braking becomes insufficient and the durability of clutches, brakes, etc. decreases. The present invention aims to solve such problems.

(d) Means for Solving the Problems The present invention solves the above problems by increasing the line pressure more when the exhaust brake device is activated than in other cases. That is, when a signal indicating that the exhaust brake device is operating is input to the line pressure control device for an automatic transmission according to the present invention, the line pressure is lower than when this signal is not input under the same operating condition. A line pressure increasing means is provided for increasing the line pressure.

(e) Operation When the exhaust brake device is activated, a signal indicating that it is activated is input to the control device of the automatic transmission, and the line pressure increasing means is activated to increase the line pressure. As a result, even if the throttle opening is fully closed, line pressure will rise when the exhaust brake device is activated, making it difficult to secure the torque capacity of the friction element required when powerful engine braking is activated. can.

(F) Embodiment FIG. 2 shows a schematic diagram of a power transmission mechanism of an automatic transmission with four forward speeds and one reverse speed with an overdrive. This power transmission mechanism includes an input shaft 13 to which rotational force from an engine output shaft 12 is transmitted via a torque converter 10, an output shaft 14 that transmits driving force to the final drive device, a first planetary gear set 15, and a second planetary gear set. Group 16. Reverse clutch 1
8, a high clutch 20, a forward clutch 22, an overrunning clutch 24, a low and reverse brake 26, a band brake 28, a row one-way clutch 29, and a forward one-way clutch 30. Note that the torque converter 10 has a lock-up clutch 11 built therein. The first planetary gear set 15 includes a sun gear S1, an internal gear R1, and a carrier PCI that supports a pinion gear P1 that meshes with both gears Sl and R1 at the same time. S2, an internal gear R2, and a carrier PC2 that supports a binion gear P2 that meshes with both gears S2 and R2 at the same time. The carrier PCI can be connected to the input shaft 13 via the high clutch 20, and the sun gear S1 is connected to the reverse clutch 1.
It can be connected to the input shaft 13 via 8. carrier PC
t can also be connected to the internal gear R2 via the forward clutch 22 and the forward one-way clutch 30 connected in series thereto, or via the overrunning clutch 24 arranged in parallel to the forward clutch 22 and the forward one-way clutch 30. be. Sun gear S2 is always connected to input shaft 13, and internal gear R1 and carrier PC2 are connected to output shaft 13.
4 is always connected. The low and reverse brake 26 can fix the carrier PC1, and the band brake 28 can fix the sun gear S1. The row one-way clutch 29 is arranged in an orientation that allows forward rotation (rotation in the same direction as the engine output shaft 12) of the carrier PCI, but does not allow reverse rotation (rotation in the opposite direction to the forward rotation).

The power transmission mechanism includes clutches 18, 20, 22 and 2.
4. By operating the brakes 26 and 28 in various combinations, each element (S
1, Sl, R1, R2, PCl, and PC2), and thereby the rotational speed of the output shaft 14 relative to the rotational speed of the input shaft 13 can be varied. By operating the clutches 18, 20, 22 and 24 and the brakes 26 and 28 in combination as shown in FIG. 3, four forward speeds and one reverse speed can be obtained. In addition, O marks in Fig. 3 indicate operating clutches and brakes, α1 and α2 are the ratios of the number of teeth of sun gears S1 and Sl to the number of teeth of internal gears R1 and R2, respectively, and the gear ratio is It is the ratio of the rotation speed of the input shaft 13 to the rotation speed of the output shaft 14.

FIG. 1 shows a hydraulic control device that controls the operation of the power transmission mechanism. This hydraulic control device includes a pressure regulator valve 40, a pressure modifier valve 4
2. Line pressure solenoid 44, modifier pressure accumulator 46, pilot valve 48, torque converter relief valve 50, lock-up control valve 52, first shuttle valve 54, lock-up solenoid 56, manual valve 58, first shift valve 60
, second shift valve 62, first shift solenoid 64,
Second shift solenoid 66, servo charger valve 68.3-2 timing valve 70.4-2 relay valve 72.4-2 sequence valve 74, first reducing valve 76, second shuttle valve 78, overrunning clutch control valve 80, overrunning clutch solenoid 82, overrunning clutch reducing valve 84.1-2 accumulator 86.2-3 accumulator 88.3-4 accumulator 90, N-D accumulator 92, accumulator control valve 94, filter 96, etc. These are connected to each other as shown in the figure, and the aforementioned torque converter 10 (in addition, the apply chamber 11a and release chamber 11b of the lock-up clutch 11 are formed in this, and the release chamber ttb When hydraulic pressure is supplied to the apply chamber 11a, the lock-up clutch 11 is released, and when hydraulic pressure is supplied to the apply chamber 11a, the lock-up clutch is engaged.
2, high clutch 20, band brake 28 (this includes an apply chamber 28a for 2nd speed, a release chamber 28 for 3rd speed)
b, and a 4th speed apply chamber 28c are formed),
Reverse clutch 18, low and reverse brake 2
6, and a variable capacity vane type oil pump 34 which is also connected to the overrunning clutch 24 as shown in the figure and further includes a feedback accumulator 32;
An oil cooler 36, a front lubrication circuit 37, and a rear lubrication circuit 38 are also connected as shown. More information about these valves.

Explanation will be omitted. The parts whose explanation is omitted are the same as those described in Japanese Patent Application Laid-Open No. 62-62047.

The line pressure solenoid 44 is connected to the control unit 30
The duty ratio is controlled by the signal from 0, and the oil passage 202
control the hydraulic pressure. The oil pressure in the oil passage 202 acts on the pressure modifier valve 42, thereby making it possible to control the oil pressure in the oil passage 204, which is regulated. The oil pressure in the oil passage 204 acts on the pressure increase side bolt 206 of the pressure regulator valve 40 . The pressure regulator valve 40 adjusts the oil pressure of the oil passage 208 to which oil discharged from the oil pump 34 is supplied, that is, the line pressure. In the control unit 300.

A signal from the exhaust brake device 216 is input,
In addition, the throttle opening sensor 212 and the vehicle speed sensor 2
A signal from 14 is also input.

Next, the operation of this embodiment will be explained. If the activation signal is not input from the exhaust brake device 216,
Control unit 300 performs normal control. That is, the line pressure solenoid 4
4, the pressure modifier valve 42 is brought into a predetermined pressure regulating state, and the pressure regulator valve 40 regulates the line pressure in accordance with the pressure modifier pressure obtained thereby.

Note that the line pressure is also controlled in accordance with a shift signal, an oil temperature signal, etc., but since these are not directly related to the present invention, their explanation will be omitted.

When the exhaust brake device 216 is activated in the above-described state, a signal from this is input to the control unit 300. When the control unit 300 receives a signal from the exhaust brake device 216, it changes the duty ratio commanded to the line pressure solenoid 44, and
Increase the oil pressure of 02. As a result, the pressure modifier pressure in the oil passage 204, which is regulated by the pressure modifier valve 42, also increases, and the pressure modifier pressure further acts on the pressure regulator valve 40, thereby causing the oil passage to be pressure regulated. 208 line pressure is increased. Since the line pressure of this oil passage 208 is supplied to each clutch, brake, etc., even if the exhaust brake device 140 is activated and strong engine braking is applied, the clutches, brakes, etc. can be reliably maintained in the engaged state. Can be done. This not only makes it possible to obtain a reliable engine braking effect, but also improves the durability of the clutch, brake, etc.

(g) As described in detail, according to the present invention, when the exhaust brake device is activated, the line pressure of the automatic transmission is increased, so that the friction element required when the exhaust brake device is activated is It is possible to secure a torque capacity of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000000000000000000 but typeling type type type type type type type type type type type type type type type type type type type type type type type type type type type type type type condition type form form of a state in its torque capacity has the ability to provide reliable engine braking operation and ensure the durability of the friction elements;

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a power transmission mechanism of a continuously variable transmission, and FIG. 3 is a diagram showing a combination of elements operating at each gear stage. 44...Line pressure solenoid, 200...Control unit, 216...m air pressure L/-ki device.

Claims (1)

[Claims] In a line pressure control device for an automatic transmission installed in a vehicle equipped with an exhaust brake device, when a signal indicating that the exhaust brake device is operating is input, the line pressure control device is configured to control the line pressure control device in a similar driving state. A line pressure control device for an automatic transmission, comprising a line pressure increasing means for increasing the line pressure compared to when no signal is input.