JPH02134457A - Oil pressure relieving device of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent speed change shock in the initial period of rising, by allowing a certain oil pressure to be applied to No.2 pressure receiving part of No.2 spool, which performs strokes through the action of the regulated oil pressure given by No.1 spool of a pressure regulating valve, and eliminating this application of oil pressure when a specified motion is attained. CONSTITUTION:When a shift valve is switched to cause supply of oil pressure from an oil path 34 to a one 30, oil pressure to a clutch 8 rises abruptly, and its attainment of a specified value causes the oil pressure at a poor 16 to balance with the force of a spring 14, and No.1 spool 10 is put in pressure regulated condition, and oil pressure from ports 25, 26 actuates leftwise stroke of No.2 spool 12. This compresses the spring 14 to boost the oil pressure on the oil path 30 to be regulated by the No.1 spool 10, and closing of the port 25 by a minor dia. land 12b of the No.2 spool 12 causes exhaustion of the oil pressure at No.2 pressure receiving part from a drain port 24, which allows only the oil pressure at the port 26 to act on the No.2 spool 12 so that the oil pressure on the oil path 30 is boosted slowly. This accomplishes reducing generation of speed change shocks.

Description

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

(b) Prior Art As a conventional hydraulic pressure relief device for an automatic transmission, for example, the Saab 9000 manufactured by Saab Scania in Sweden (
There is one with the ZF4) IP18 type automatic transmission shown in the service manual (published in 1986) of the product name). The hydraulic relief device for the automatic transmission shown here consists of a spool,
It has an accumulator piston and a spring.

The spool is configured as a pressure regulating valve and regulates the hydraulic pressure against the spring force and throttle readjustment pressure. The spool is connected so that the regulated pressure acts on the accumulator piston to stroke it. A spring is disposed between the accumulator piston and the spool, and the spring force increases with the stroke of the accumulator piston.

Therefore, the regulated pressure regulated by the spool increases with the passage of time. Since this adjustment pressure is supplied to a predetermined friction element, the friction element is tightened by the adjustment pressure that gradually increases over time.

(C) Problems to be Solved by the Invention However, in the conventional automatic transmission hydraulic pressure relief device as described above, when the gear shift is switched from the torque phase to the inertia phase, the torque is reduced as shown by the broken line in FIG. The problem is that the gear overshoots and the shifting feeling is not favorable. In other words, in this hydraulic pressure relief device, a hydraulic pressure that increases linearly with the stroke of the accumulator piston is obtained, and the switching from the torque phase to the inertia phase is performed by the hydraulic pressure value near when the accumulator piston starts its stroke. ,
The torque capacity becomes relatively large and torque overshoot occurs, causing the above-mentioned problems. The present invention
The aim is to solve the problems mentioned above.

(d) Means for Solving the Problems The present invention solves the above problems by making the hydraulic characteristics obtained by the hydraulic pressure relief device two-stage, with a bend in the middle, and by lowering the oil pressure in the first stage. That is,
The hydraulic pressure relief device for an automatic transmission according to the present invention has a first spool and a second spool inserted into a common valve hole, and a spring disposed between the two, and the first spool has a shaft acting from the spring. The second spool is configured as a pressure regulating valve that regulates the hydraulic pressure so as to counter the directional force, and the second spool has a first pressure receiving part and a second pressure receiving part that apply a force in the opposite direction to the spring when the hydraulic pressure acts. The regulated pressure regulated by the first spool always acts on the first pressure receiving part of the second spool regardless of the position of the second spool, and the second pressure receiving part of the second spool always acts on the second pressure receiving part of the second spool. When the spool is pushed by the spring and is at the stop position, the adjustment pressure acts, and when the second spool moves more than a predetermined amount in the spring compression direction, the hydraulic pressure is not applied, and the adjustment pressure is applied to the 11 predetermined medical elements. Supplied.

In addition, the present invention having another configuration includes a first spool and a second spool inserted into a common valve hole, and a spring disposed between the two, and the first spool receives an axial force acting from the spring. The second spool is configured as a pressure regulating valve that regulates the hydraulic pressure so as to counteract the pressure, and the second spool has a first pressure receiving part that applies a force in the opposite direction to the spring when the hydraulic pressure is applied, and a second pressure receiving part that applies a force in the same direction as the spring when the hydraulic pressure acts. and a second pressure receiving part that applies a force in the direction, and the first pressure receiving part of the second spool
The adjustment pressure regulated by the first spool always acts on the pressure receiving part regardless of the position of the second spool, and the second spool is pushed by a spring to the stop position on the second pressure receiving part of the second spool. When the second spool is on the side, no hydraulic pressure is applied, and when the second spool moves more than a predetermined amount in the spring compression direction, the oil chamber formed by the second pressure receiving part is closed, and the adjusted pressure reaches the predetermined l! It is supplied to the J rubbing element.

(e) At the initial stage where the operating adjustment pressure is low, the adjustment pressure acts on both the first pressure receiving part and the second pressure receiving part of the second spool. Therefore,
The second spool moves rapidly in the direction of compressing the spring, and the regulated pressure rises relatively quickly from a low value. Next, when the second spool moves toward the first spool and the adjustment pressure no longer acts on the second pressure receiving portion, the adjustment pressure gradually increases. This is because the force due to the adjustment pressure acting on the second spool is reduced by the second pressure-receiving portion, and thus the moving speed of the second spool is reduced.

Therefore, the adjusted pressure has curved characteristics at the initial stage and at the stage after the adjusted pressure no longer acts on the second pressure receiving portion. This allows the oil pressure in the first stage to be set low. Since a change from the torque phase to the inertia phase occurs due to this low oil pressure, it is possible to prevent the occurrence of torque overshoot and improve the shift feeling.

In another configuration of the present invention, when the second spool moves toward the first spool, a resistance force is generated in the second pressure receiving portion, so that it is possible to obtain an adjustment pressure with the same bending characteristics as described above.

(f) Example (First example) 1 and 2 show a first embodiment of the present invention.

The first spool lO and the second spool 12 are arranged within the same valve body, and a spring 14 is arranged between them. The first spool 10 has two lands 10a of equal diameter.
and lOb.

The second spool 12 has a large diameter land 12a and a small diameter land 1.
2b. There are 8 boats in the valve hole 16.18.
20, 22, 23, 24, 25 and 26 are provided. Boats 16, 20, 25 and 26 communicate with an oil line 30 which is connected to clutch 28. boat 16.25
and 26 are provided with orifices 32, 36 and 38, respectively. The boat 18 communicates with an oil passage 34 through which hydraulic pressure for gear shifting is supplied from a shift valve. Boats 22, 23 and 24 are drain boats.

The positions of the boats 16, 18, 20 and 22 and the dimensional relationship of the lands 10a and 10b of the first spool 10 are as follows:
The spool 10 is configured to act as a pressure regulating valve. That is, the oil pressure of the boat 16 is of a magnitude that balances the force acting from the spring 14. The oil pressure of the boat 26 is always applied to the end surface of the small diameter land 12b of the second spool 12 (
(first pressure receiving part). In addition, in the illustrated state, the boat 25 has a large diameter land 12a and a small diameter land 1 of the second spool.
2b (second pressure receiving part), but when the second spool 12 moves to the left by a predetermined amount in FIG. 1, it is closed by the small diameter land part 12b, and the second pressure receiving part 24.

Next, the operation of this embodiment will be explained. When a shift valve (not shown) is switched and hydraulic pressure is supplied to the oil passage 34, this oil pressure is supplied to the oil passage 30, and the oil pressure of the clutch 28 starts to rise rapidly (time 1+ in Fig. 2).
). When the oil pressure in the oil passage 30 rises to a predetermined value P1, the oil pressure acting on the boat 16 becomes balanced with the force acting from the spring 14, and the first spool 10 enters a pressure regulating state. The oil pressure in the oil passage 30 is also supplied to the boats 25 and 26, and the force due to this oil pressure acts on the second spool 12, so the second spool 12 starts to stroke leftward in the figure. As the second spool 12 moves to the left in the figure, the spring 14 is compressed, and the first spool 1
The oil pressure of the oil passage 30, which is regulated by 0, increases.

When the small diameter land 12b of the second spool 12 moves to the position where the boat 25 is closed, the hydraulic pressure acting on the second pressure receiving part starts to be discharged to the drain boat 24 (the second
time t2 and oil pressure P2 in the figure). From this point on, the second spool 12 moves relatively slowly. This is boat 2
This is because only the oil pressure of No. 6 applies force to the second spool 12. As a result, the oil pressure in the oil passage 30 gradually rises, and eventually the second spool 12 becomes the first spool 1.
0 and press the stiffness to the leftmost position. As a result, the oil pressure in the oil passage 34 is supplied to the oil passage 30 as it is (time t3 in FIG. 2). In the end, clutch 28
As shown in FIG. 2, the hydraulic pressure supplied to
It increases in two stages: stage 2 and stage t2 to t3. Therefore, time 1. A relatively low oil pressure acts on the clutch 28 during the period from t2 to t2. Therefore,
The occurrence of torque overshoot when switching from the torque phase to the inertia phase is prevented, and a good shift feeling can be obtained.

(Second Embodiment) FIG. 3 shows a second embodiment. The first spool 10 side of this second embodiment is the same as that shown in the first embodiment. However, on the second spool 13 side, the spring 14 side is a small diameter land 13a, and the side facing the boat 26 is a large diameter land 13b. Therefore, when hydraulic pressure acts on the end surface side of the large-diameter land 13b, which is the first pressure-receiving portion, a force acting in a direction opposing the spring 14 acts on the second spool 13, but the large-diameter land 13b, which is the second pressure-receiving portion, acts on the second spool 13. When hydraulic pressure acts between the small diameter land 13a and the small diameter land 13a, a force acts in the same direction as the force of the spring 14. Further, the small diameter land 13a is configured to fit into the small diameter portion of the valve hole when the second spool 13 moves a predetermined amount toward the first spool 10.

In this second embodiment as well, the same effect as in the first embodiment described above can be obtained. That is, the second spool 13 moves rapidly from the state shown in FIG. 3 to the first spool 10 side by a predetermined amount, but the small diameter land portion 13a
When it fits into the small diameter part of the valve hole, the oil between the small diameter land 13a and the large diameter land 13b becomes trapped, and the movement of the second spool 13 to the left in FIG. give resistance. Therefore, the second spool 13 strokes slowly, and it is possible to obtain hydraulic characteristics substantially similar to the hydraulic characteristics shown in FIG. 2 described above.

(g) As described in detail, according to the present invention, the rise in hydraulic pressure is alleviated by the pressure regulating valve constituted by the first spool and the second spool stroked by the hydraulic pressure adjusted by the pressure regulating valve. In this case, the hydraulic pressure that was acting on the second pressure receiving part of the second spool is made to stop acting when the second spool moves beyond a predetermined value.
The pressure adjusted by the pressure regulating valve has a bending characteristic, and the oil pressure at the initial stage of oil pressure rise can be lowered to reduce shift shock. Further, the same effect can be obtained even if the resistance force is increased when the second spool moves beyond a predetermined value.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a diagram showing hydraulic characteristics etc. obtained by this embodiment, and FIG. 3 is a diagram showing a second embodiment of the present invention. 10...first spool, 12...second spool, 1
4...Spring. Patent applicant: Nissan Motor Co., Ltd. Attorney: Toshiyuki Miyauchi

Claims (1)

[Claims] 1. A first spool and a second spool inserted into a common valve hole, and a spring disposed between the two;
The spool is configured as a pressure regulating valve that regulates the hydraulic pressure so as to counteract the axial force acting from the spring, and the second spool is configured as a first pressure receiving part that applies a force in a direction opposing the spring when the hydraulic pressure acts. The adjustment pressure regulated by the first spool always acts on the first pressure receiving part of the second spool regardless of the position of the second spool. The pressure receiving part has a second
Adjustment pressure acts when the spool is pushed by the spring and is at the stop position, and hydraulic pressure does not act when the second spool moves more than a predetermined amount in the spring compression direction, and the adjustment pressure is supplied to a predetermined friction element. Hydraulic relief device for automatic transmission. 2. The first spool has a first spool and a second spool inserted into a common valve hole, and a spring disposed between the two.
The spool is configured as a pressure regulating valve that regulates the hydraulic pressure so as to counteract the axial force acting from the spring, and the second spool is configured as a first pressure receiving part that applies a force in a direction opposing the spring when the hydraulic pressure acts. , and a second pressure receiving part that applies a force in the same direction as the spring when hydraulic pressure is applied, and the first pressure receiving part of the second spool receives the adjusted pressure regulated by the first spool. It always acts on the second pressure receiving part of the second spool regardless of the position of the spool.
When the second spool is pushed by the spring and is at the stop position, no hydraulic pressure is applied, and when the second spool moves more than a predetermined amount in the spring compression direction, the oil chamber formed by the second pressure receiving part is in a sealed state. A hydraulic relief device for an automatic transmission configured to provide a regulating pressure to a predetermined friction element.