JPH01247852A - Hydraulic control device for automatic speed change gear - Google Patents

Abstract

PURPOSE:To improve a driving feeling through immediate production of an engine brake effect, by a method wherein the back pressure receiving part of an accumulator piston is increased in a line pressure in an engine brake range compared with a case of a range D. CONSTITUTION:During a third step in a range D, an oil pressure is fed from a 2-3 shift valve 66 to engage a high-clutch H/C and disengage a hand brake B/B by means of a servo piston 130. An oil pressure is exerted on an actuating pressure receiving chamber 112 of a servo release accumulator 90, and a line pressure is exerted as a back pressure on a first back pressure receiving chamber 116 through an oil passage 118. When a gear is shifted to a second step in a range 2, a line pressure is also fed to a second back pressure receiving chamber 120 through an oil passage 122, through sudden raise of a piston 114, an oil pressure in a release chamber 3R for a third step is rapidly discharged. The B/B is forced into a engaged state in a short time, and an engine brake effect at a second step is immediately produced. This constitution enables improvement of a driving feeling.

Description

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

(b) Conventional technology As a conventional hydraulic control device for an automatic transmission,
There is one shown in Publication No. 62047. The hydraulic control device for the automatic transmission shown therein includes a band brake that is released when the gear is in the third gear and is engaged when the gear is in the second gear, and a hydraulic servo device for controlling the band brake. The operating pressure of an oil chamber for releasing the band brake of this hydraulic servo device, that is, a servo release chamber, is configured such that changes in oil pressure are alleviated by an accumulator. The piston of the accumulator is supplied with line pressure during forward movement as a back pressure that generates a force opposing the operating pressure.

(c) Problems to be Solved by the Invention However, in the conventional automatic transmission hydraulic control device as described above, the accumulator is Since it is configured to perform a similar action, there are problems such as a delay in shift response and a feeling of insufficient engine braking effect when shifting from 3 to 2 when the 2 range is selected. That is, during the 3-2 gear shift, the hydraulic pressure in the servo release chamber is drained, but the accumulator piston is pushed by the line pressure acting on its back pressure receiving portion and moves in the direction to drain the hydraulic pressure in the servo release chamber.

The area of the back pressure receiving portion of the accumulator piston is smaller than the area of the operating pressure receiving portion of the accumulator piston, and the accumulator piston moves slowly.

The moving speed of the accumulator piston, ie, the discharge speed of the hydraulic pressure in the servo release chamber, is set to make the 3-2 shift in the D range appropriate.

For this reason, even when the 2nd range is selected, the band brake is released at the same timing, so while the accumulator piston is moving, the band brake's torque capacity is small, causing a delay in gear shifting and an increase in engine speed. A problem arises in which the braking effect feels insufficient. Since selecting the 2nd range is a driving condition that requires a rapid engine braking effect, the above-mentioned problem becomes noticeable. The present invention aims to solve the above problems.

(d) Means for Solving the Problems The present invention solves the above problems by increasing the back pressure receiving portion of the accumulator piston in the engine braking range. That is, in the hydraulic control device for an automatic transmission according to the present invention, the piston of the accumulator has a working pressure receiving part on which the working pressure of the friction element hydraulic chamber acts, and two back pressure receiving parts on which a force in the opposite direction is applied. One of the back pressure receiving parts is always supplied with hydraulic pressure at least when operating pressure is supplied to and discharged from the friction element hydraulic chamber, and the other back pressure receiving part is supplied with hydraulic pressure from the predetermined gear stage. The system is configured so that hydraulic pressure is supplied when the engine brake range for shifting to a lower gear is selected.

(E) Function For example, in the case of the D range, the accumulator operates as before by the hydraulic pressure acting on one of the back pressure receiving sections. In the case of engine braking range (for example, 2 range), hydraulic pressure acts on one back pressure receiving part as well as the other back pressure receiving part, so the accumulator piston moves rapidly and shifts from a predetermined gear. A rapid shift is performed to a gear position lower than this (for example, from D range 3rd gear to 2nd range 2nd gear). This allows the engine brake to work directly on the vehicle, improving the driving feeling.

(F) Embodiment FIG. 2 shows a skeleton diagram of an automatic transmission (automatic transaxle). The automatic transmission connected to the engine 10 mounted horizontally with respect to the vehicle, that is, perpendicular to the longitudinal direction of the vehicle, includes a torque converter 12, a planetary gear transmission mechanism 14, a differential mechanism 16, etc. There is. Torque converter 1 whose rotation from engine io is manually powered
2 has a pump impeller 18, a turbine runner 20, a stator 22, and a lock-up clutch 24. The turbine runner 20 is connected to a human-powered shaft 26, and when the lock-up clutch 24 is released, rotational force is transmitted from the pump impeller 18 to the human-powered shaft 26 via fluid, and the lock-up clutch 24 is engaged. A rotational force is mechanically applied to the human-powered shaft 26. The lock-up clutch 24 is operated by the differential pressure between the apply chamber T/A and the release chamber T/R. Note that the torque converter 12 is configured to drive the oil pump 2B. The planetary gear transmission mechanism 14 has a 7jS1 planetary gear set G and a second planetary gear set G2, and the first planetary gear set G
, is the first sun gear S- and the first internal gear R3.
and a first pinion carrier PCI that supports a first pinion gear P1 that meshes with both gears S and R1 at the same time, and a second TL star gear set G2 includes a second sun gear S2 and a second internal gear R2. and both gear S
2 and a second pinion carrier PC2 that supports a second pinion gear P2 that meshes with R2 at the same time. The first sun gear S is always connected to the human power shaft 26, and the first pinion carrier PC and the second internal gear R2 are always connected to the output shaft 30.

The first internal gear R1 is connected to the second pinion carrier PC via a forward one-way clutch F10 and a forward clutch F/C arranged in series, and an overrun clutch O/C arranged in parallel thereto.
Can be connected with 2. The second sun gear S2 can be connected to the human power shaft 26 via a reverse clutch R/C, and the second pinion carrier PC2 can be connected to the human power shaft 26 via a high clutch H/C. The second sun gear S2 can be fixed to a stationary part by a band brake B/B, and the second sun gear and the nion carrier PC2 are connected to each other via a row one-way clutch L10 and a low and reverse brake L&R/B, which are arranged in parallel with each other. can be fixed to a stationary part. An output gear 32 is provided integrally with the output wheel 30. An idler gear 34 is provided to mesh with the output gear 32, and a reduction gear 736 is connected to the idler gear 34 via an idler shaft 35 so as to rotate together with the idler gear 34.

The reduction gear 36 is a ring gear 38 of the differential mechanism 16.
They are interlocked. Drive shafts 40 on the left and right from the differential mechanism 16
and 42 protrude, to which the left and right front wheels are connected.

This planetary gear transmission mechanism 14 includes clutches F/C, H/C
, 0/C and R/C, brake B/B and L&R/B,
By operating the one-way clutches F10 and Llo in various combinations, each element of the planetary tooth east set G and G2 (S+, S2, R+, R2, Pct and p
c2) can be changed, thereby making it possible to variously change the rotational speed of the output shaft 30 with respect to the input shaft 26. That is, four forward speeds and one reverse speed can be obtained by operating each clutch, brake, etc. in combination as shown in FIG. In addition, O in Figure 3
The mark indicates that the clutch and brake are engaged,
In the case of a one-way clutch, it also indicates the engaged state. Also, 2A, 3R, and 4A in the band brake B/B column are respectively the 2-speed apply chamber 2A, the 3rd speed release chamber 3R, and the 4th speed river apply chamber 4A of the hydraulic servo device that operates the band brake B/B. The O mark indicates that hydraulic pressure is being supplied. Further, G1 and G2 are the ratios of the number of teeth of sun gears SI and S2 to the number of teeth of internal gears R1 and R2, respectively, and the gear ratio is the ratio of the number of rotations of the human power shaft 26 to the number of rotations of the output shaft 30. .

By the operation of the planetary gear transmission mechanism 14 as described above, the rotation of the human power shaft 26 is changed in a predetermined speed and outputted to the output shaft 30. The rotational force of the output shaft 30 is transmitted to the ring gear 38 of the differential mechanism 16 via the output gear 32, the idler gear 34, and the reduction gear 36. Thereby, the left and right surface widths can be driven via the drive shafts 40 and 42. By doing so, it is possible to perform an automatic 4-speed surface forward shift with overdrive.

FIG. 4 shows a hydraulic circuit of a hydraulic control device for controlling the power transmission mechanism.

This hydraulic control device includes a Brennyer regulator valve 50, a manual valve 52, a throttle valve 54, a throttle modifier valve 56, a pressure modifier valve 58, a lockup control valve 60, a governor valve 62.1-2 a shift valve 64.2
-3 shift valve 66.3-4 shift valve 68.3-
2 timing valve 70, 4-2 sequence valve 72
, l-speed fixed range pressure reducing valve 74, speed cut valve 76, overrun clutch control valve 78.
It has a 1-2 accumulator valve 80, a kickdown modifier valve 82, an overdrive inhibitor solenoid 84°N-D accumulator 88, and a servo release accumulator 90. It is connected as shown in the figure, and the oil pump O/P and the application chamber T of the torque converter 12 are connected as shown in the figure.
/A and release chamber T/R, clutch R/C, H/C1
It is also connected to the three i2A, 3R and 4A of 0/C and F/C, brake L&R/B, and band brake B/B as shown. With this configuration, the clutch R/
C, H/C, O/C and F/C1 and brake L&R/
B and B/B operate as shown in the table above, but detailed explanations of valves and the like other than those directly related to the present invention will be omitted. In order to facilitate understanding, the following explanation will be based on FIG. 1, which shows only the parts directly related to the present invention.

The 2-3 shift valve 66 switches depending on the magnitude of the governor pressure and throttle modulation pressure that act against each other, and does not output hydraulic pressure to the oil passage 100 in the down position, but outputs oil pressure to the oil passage 100 in the up position. Output the line pressure to 100. An oil passage 104 connected to the oil passage 100 via an orifice 102 is connected to a high clutch H/C. Further, the oil passage 104 is connected to the oil passage 10 through the orifice 106.
8 is connected. Note that the orifice 102 is actually constructed by arranging two one-sided orifices in series, as shown in FIG. Also, the orifice 106 is actually the 3-2 timing valve 70.
However, it is shown in a simplified manner in FIG. The oil passage 10B is connected to the third speed release chamber 3/R formed by the servo piston 130 of the band brake B/H. Further, the oil passage 108 communicates with an operating pressure receiving chamber 112 of the servo release accumulator 90. The servo release accumulator 90 has a stepped piston 114 and a spring 115, and the above-mentioned working pressure receiving chamber 112 is formed on the large diameter side (working pressure receiving part) of the stepped piston 114 and the spring 115. A first back pressure receiving chamber 116 is formed between the small diameter part (one back pressure receiving part), and line pressure is supplied to this first back pressure receiving chamber 116 as back pressure from the oil passage 11B during forward movement. It is. Further, the second back pressure receiving chamber 120 on the small diameter side (the other back pressure receiving part) of the piston 114 is connected to an oil passage 122, and this oil passage 122 is drained in the D range, and in the 2 range. Line pressure is supplied (in addition, oil line 22
line pressure is supplied even when reversing).

Next, the operation of this embodiment will be explained.

At the 3rd speed of the D range, hydraulic pressure is supplied from the 2-3 shift valve 66 to the oil passage 100, the high clutch H/C is engaged, and the hydraulic pressure acts on the 3rd speed release chamber 3/R, and the servo piston 130 is activated. It is in the position to release band brake B/B. Further, oil pressure is applied from the oil passage 108 to the operating pressure receiving chamber 112 of the servo release accumulator 90, and the piston 114 is in a stroked state as shown in the left half of the figure. As back pressure, line pressure acts on the first back pressure receiving chamber 116 from the oil passage 118, while no hydraulic pressure acts on the second back pressure receiving chamber 120.

When a 3-2 shift in the D range is performed from this state, the oil pressure in the oil passage 100 is drained, and thereby the oil pressure in the oil passages 104 and 108 are also drained. At this time, the piston 11 of the servo release accumulator 90
4 is stroked in the -F direction in the figure by the hydraulic pressure acting on the first back pressure receiving chamber 116 and the force of the spring 115, and the hydraulic pressure in the working pressure receiving chamber 112 is transferred to the oil passage 108 and the orifice 106.
, the oil passage 100 through the oil passage 104 and the orifice 102.
to be discharged. The upward stroke of the piston 114 at this time is relatively gentle.

This is because the piston 114 is stroked only by the hydraulic pressure acting on the first back pressure receiving chamber 116. As a result, the 3-2 shift is performed relatively slowly, and the shift shock is small.

Next, when a shift is performed from the third speed of the D range to the second speed of the 2nd range, line pressure is also supplied from the oil passage 122 to the second back pressure receiving chamber 120 of the servo release accumulator 90. Therefore, the piston 114 is in the first back pressure receiving chamber 11
6 and the second back pressure receiving chamber 120, it is pushed by the hydraulic pressure acting on both the second back pressure receiving chamber 120 and moves upward. In this case, the stroke speed increases by the amount of oil pressure acting on the second back pressure receiving chamber 120, and the oil pressure in the oil path 10B is rapidly discharged. Therefore, the hydraulic pressure in the third speed release chamber 3/R is also rapidly discharged, and the band brake B/B is brought into the engaged state within a short time. Therefore, the 3-2 gear shift in this case is performed rapidly, and the engine braking effect of the second gear can be immediately obtained.

(g) As described in detail, according to the present invention, the back pressure receiving portion of the accumulator piston is made to be larger in the engine brake range than in the D range, so that the engine brake range is selected. In this case, the gears can be changed quickly and the engine braking effect can be immediately obtained, improving the driving feeling.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a skeleton diagram of an automatic transmission, Fig. 3 is a diagram showing the combination of elements that operate at each gear stage, and Fig. 4 is a diagram showing the entire hydraulic circuit. It is a diagram. 66...2-3 shift valve, 90...servo release accumulator, 102... -orifice, 1
06... Orifice. 114... Piston % 130... Servo piston, B/B... Band brake, 3/R... 3rd gear release chamber.

Claims (1)

[Scope of Claims] Hydraulic pressure of an automatic transmission having a friction element hydraulic chamber to which operating pressure is supplied when realizing a predetermined gear stage, and an accumulator that alleviates changes in the operating pressure of the friction element hydraulic chamber. In the control device, the piston of the accumulator has a working pressure receiving part on which the working pressure of the friction element hydraulic chamber acts, and two back pressure receiving parts on which a force in a direction opposing the working pressure acts. Hydraulic pressure is always supplied to the back pressure receiving part at least when the working pressure is supplied to and discharged from the friction element hydraulic chamber, and the other back pressure receiving part is used for shifting to a gear lower than the predetermined gear. A hydraulic control device for an automatic transmission, characterized in that it is configured to supply hydraulic pressure when an engine brake range is selected.