JPS6040854A - Speed change control device of speed change gear - Google Patents

Abstract

PURPOSE:To moderate a speed change shock at the time of low-load speed change by variably throttling the quantity of oil discharged from an accumulator of one already engaged frictional engagement element with operating pressure of a newly engaged clutch. CONSTITUTION:A speed changeshock control valve 6a is interposed between an oil path 61 diverged from an operating oil path 46 and an oil path 62 communicating with an accumulator 55. By the operating pressure of a newly engaged clutch C3, the quantity of oil discharged from the accumulator 55 is variably throttled. Thus, a speed change shock at the time of a low-load speed change can be moderated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed change control device for a gear transmission, particularly a gear train having a plurality of stages having different speed ratios; at least two frictional engagement elements; at least two hydraulic actuation means for engaging and operating each frictional engagement element, which are individually attached to each frictional engagement element; and for supplying oil to each hydraulic actuation means; a hydraulic source for; selectively supplying pressure oil from the hydraulic source to both of the hydraulic actuating means;
The purpose of the gear transmission control device is to sufficiently alleviate the shift shock during gear shifting, and to achieve a downshift operation that is timed with the engine output. An object of the present invention is to provide a speed change control device that can perform the following functions.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
First, in FIG. 1 showing an outline of an automatic gear transmission for an automobile with three forward speeds and one reverse speed to which the present invention is applied, engine E
The output of is from the crankshaft 1 to the torque converter T,
The drive wheels F, sequentially pass through the auxiliary transmission M and the differential Df.
It is transmitted to F' and drives them.

The torque converter T includes a pump impeller 2 connected to a crankshaft 1, a turbine impeller 3 connected to an input shaft 5 of an auxiliary transmission H, and a stator shaft 4α that is relatively rotatably supported on the input shaft 5. It is composed of a stator impeller 4 connected via a one-sided clutch 7. The torque transmitted from the crankshaft 1 to the pump wheel 2 is hydrodynamically transmitted to the turbine wheel 3, and when the torque is amplified during this time, the stator wheel 4 is bear power.

A pump drive gear 8 for driving the hydraulic pump P shown in FIG. 3 is provided at the right end of the pump impeller 2, and a stator shaft 4a
A stator arm 4b for controlling the regulator valve Vγ shown in FIG. 3 is fixedly installed at the right end of the stator arm 4b.

The auxiliary transmission M has a low speed gear train G1, a middle speed gear train G2, and a high speed gear train G between the output shafts 5 and 6 of the auxiliary transmission M, which are parallel to each other.
3, and a reverse gear train Gτ are provided in parallel. The low-speed gear train G1 includes a drive gear 17 connected to the input shaft 5 via a low-speed clutch C5 as a frictional engagement element, and a drive gear 17 connected to the output shaft 6 via a one-way clutch C6.
The intermediate speed gear train G2 includes a drive gear 19 connected to the input shaft 5 via a medium speed clutch C2 as a frictional engagement element, and a driven gear 18 that meshes with the output shaft 6. The high-speed gear train G3 includes a driven gear 20 that is connected via a switching clutch Cs and meshes with the gear 19, and a high-speed gear train G3 includes a drive gear 21 fixed to the input shaft 5 and a friction engagement element on the output shaft 6. The reverse gear train Gγ includes a driven gear 22 connected via a high speed clutch C3, and a drive gear 23 formed integrally with the drive gear 1 of the middle speed gear train G2, and an output shaft. 6, the switching clutch C
A driven gear 24 connected via η, and both gears 23
．． 24 and an idle gear 25 meshing with the idler gear 24.

The switching clutch Cs is provided in the middle of the driven gear 20.24, and outputs the driven gear 20.24 by shifting the selector sleeve 26 of the clutch Cs to a forward position on the left or a reverse position on the right in the figure. It can be selectively connected to the shaft 6.

Thus, when the selector sleeve 26 is held in the forward position as shown in the figure, if only the low gear clutch C1 is connected, the drive gear 11 is connected to the input shaft 5 and the low gear train Gl is established. , torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train G1. Next, if the middle speed clutch C2 is connected while the low speed clutch C1 remains connected, the drive gear 19 is connected to the input shaft 5 and the medium speed μ gear train G2 is established. Torque is transmitted from the input shaft 5 to the output shaft 6 via the input shaft 5. During this time, the output shaft 6 rotates at a higher speed than the driven gear 18 of the low-speed gear train G due to the difference in gear ratio between the low- and middle-speed gear trains Gl and G2, so the one-way clutch C8 is idle. Thus, the low speed gear train G1 is substantially stopped. Also, low speed clutch C
In the mechanically connected state, if the middle speed clutch C2 is disconnected and the high speed clutch C3 is connected, the driven gear 22
is connected to the output shaft 6 to establish a high-speed gear train G3, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train G3. In this case as well, the one-way latch co is idling and the low speed gear train G1
pause. Next, by switching the selector sleeve 26 to the right reverse position and connecting only the middle speed clutch C2', the driving gear 23 is connected to the input shaft 5K, the driven gear 24 is connected to the output shaft 6, and the reverse gear train is connected. Gγ is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train Gγ.

The torque transmitted to the output shaft 6 is transmitted from an output gear 27 provided at the end of the output shaft 6 to a large-diameter gear 28 of the differential J)/.

In this auxiliary transmission M, when a shift amplifier or a downshift is performed between the speed ratios of the high speed gear and the middle gear, either the middle gear clutch C2 or the high gear clutch C3 is extracted from one side, and either The other side must be refueled, but by controlling the timing, the shift shock can be significantly alleviated.

FIG. 2 is a hydraulic circuit diagram showing a simplified configuration of the speed change control device according to the first embodiment of the present invention, in which a hydraulic pump P sucks up oil from an oil tank R and pumps it into a hydraulic oil passage 29. After this pressure oil is regulated to a predetermined pressure by a regulator valve Vr, it is sent to a manual valve Vm and a governor valve VgK. This oil pressure is called line pressure pt. The manual valve Vm has shift positions such as a neutral position, a drive position, and a reverse position, and is interposed between the hydraulic oil passage 29 and the oil passages 30 and 31. The oil passage 3o is connected to the throttle valve Vt, the oil passage 31 is connected to the low-medium speed shift valve V,
The hydraulic oil passage 32 branched from the oil passage 31 is connected to the low speed clutch C.
1 hydraulic actuation means M. When this manual valve Vm is in the neutral position, the hydraulic oil passage 29 does not send the line pressure PL to any line, and when it is in the drive position, the hydraulic oil passage 29 is connected to the oil passages 30, 31, 31, 31, communicate with each other.

Each clutch CI, C2, C3 is a hydraulic actuating means i1/1
rM 2 HiW 3, and their hydraulic actuating means M1 to M3 are hydraulic cylinders 331, 3.
32° 333 and its hydraulic cylinders 331, 332.
The pistons 34+, 342 . 34
It consists of 3. These hydraulic actuation means MI+1
1/2 + 11/3 is the hydraulic cylinder 331-3
When hydraulic oil is supplied to 33, the pistons 34□ to 34
3 to frictionally engage the corresponding clutches 01 to C3.

The governor valve Vg is driven by the output shaft 6 of the auxiliary transmission H or the large-diameter gear 28 of the differential gear DJ, and outputs oil pressure proportional to the vehicle speed, that is, governor pressure/j g, to its output oil path 35. Further, the throttle valve 1/t is controlled according to the amount of depression of a throttle pedal (not shown), and outputs a throttle pressure Pt proportional to the throttle opening of the engine E (ie, engine output) to the output oil path 36. These governor pressure Pg and throttle pressure pt are
36 to pilot hydraulic chambers 42a, 42b; 43a, 4'3b at both ends of the low-medium speed shift valve V1 and the medium-high speed shift valve V2 as a switching means.

The low-medium speed shift valve V is interposed between the oil passage 31 and the oil passage 38 provided with the throttle 3γ, and is in the right-hand closed position where the spring 39 and the throttle pressure pt block both side passages 31.3B. The spool valve body 40 is energized, and both sleeve passages 3 are
The spool valve body 40 is located in the open position on the left side communicating with 1 and 38.
A click motion mechanism 41 is provided at the right end of the spool valve body 40 so that the opening/closing switching action can be performed alternatively.

In this low-medium speed shift valve V, the spool valve body 40
initially remains in the closed position shown in the figure due to the force of the spring 39, but as the vehicle speed increases, the governor pressure P! increases, and this governor pressure P! When the left power of the spool valve body 4° due to I overcomes the right power of the valve body 40 due to the throttle pressure pt and the spring 39, the click ball 44 of the click motion mechanism 41
The valve body 40 moves to the left together with the valve body 4° to overcome the fixed positioning protrusion 45, and the valve body 40 quickly switches to the left open position. As a result, the hydraulic oil from the hydraulic pump P, which had previously been supplied only to the hydraulic cylinder 33 of the low-speed clutch C1, is now supplied via the oil passage 38, the medium-high speed shift valve V2, and the hydraulic oil passage 46. It is also sent to the hydraulic cylinder 332 of the middle speed clutch C2.

As a result, both clutches C, , C2 are engaged, and the middle speed gear train G2 is established as described above.

The medium-high speed shift valve V2 includes an oil passage 38 and a hydraulic oil passage 46 that communicates with the hydraulic cylinder 332 of the intermediate speed clutch C2.
and a hydraulic oil passage 47 leading to the hydraulic cylinder 333 of the high-speed clutch C3, and the spool valve body 48 communicates the oil passages 38 and 46, and has a variable throttle 49 to open oil that communicates with the oil tank B. A first switching position on the right side where the passage 50 is communicated with the hydraulic oil passage 47, and a left side where the open oil passage 52, which communicates the oil passages 38 and 47 and is equipped with a throttle 51 and communicates with the oil tank R, is communicated with the hydraulic oil passage 46. and the fourth switching position. This spool valve body 48 has
The spring 53 and the throttle pressure Pi act as right power, and the governor pressure pg acts as left power. Moreover, a click motion mechanism 54 is provided at the right end of the spool valve body 48 so that the switching action between the two positions can be performed alternatively.
is provided.

When the vehicle speed further increases, the same effect as that of the low-medium speed shift valve V occurs in the medium-high speed shift valve V2, and the spool valve body 48 is switched to the second switching position by the increasing governor pressure pg, and the hydraulic fluid is The passage 47 is communicated with the open oil passage 50,
Since the hydraulic oil passage 46 is communicated with the open oil passage 52, the middle speed clutch c2 is disconnected and the high speed clutch C3 is engaged. Therefore, the low and high speed clutches C, C3 are engaged,
The high speed gear train G is established as described above.

The opening degree of the variable throttle 49 is controlled by the throttle pressure Pt. That is, when the throttle pressure Pt is large, the opening degree of the variable throttle 490 is made small, and the throttle pressure p
When t is small, the opening degree of the variable diaphragm 49 is made large. This variable throttle 49 has a function of reducing the flow resistance of the oil drain path for discharging waste oil from the hydraulic cylinder 333 of the high speed clutch C3 to the oil tank R when downshifting from the high speed gear to the middle speed gear. fulfill. Further, the throttle 37 provided in the middle of the oil passage 38 is configured to prevent the hydraulic cylinder 33 from moving when the middle speed clutch C2 or the high speed clutch C3 is pressurized and engaged.
□ or 333 functions to moderate the pressure rise.

Accumulators 55, 56 are connected in parallel to the middle speed clutch C2 and the high speed clutch C3, respectively, and the throttle pressure pt is introduced into each back pressure chamber 57, 58 of these accumulators 55, 56. . As a result, the "hardness" of each accumulator 55, 56 changes according to the throttle opening, and this change in "hardness" works together with the shift shock control valve 60 as a control means to be described next to control the shift shock. It greatly contributes to relaxation.

The shift shock control valve 60 is interposed between an oil passage 61 branching from the hydraulic oil passage 46 and an oil passage 62 communicating with the accumulator 55. This shift shock control valve 60 includes a spool valve body 63 that is movable between a first switching position on the left side and a second switching position on the right side, and a first pilot hydraulic chamber 64 facing the left end of the valve body 63. It has a second pilot hydraulic chamber 65 that the right end of the valve body 63 faces, and a spring 66 that is housed in the second pilot hydraulic chamber 65 and urges the valve body 63 to the left.

Throttle pressure Pt (1) is introduced into the first Byrond hydraulic chamber 64, and operating pressure p i+ is introduced into the second pilot hydraulic chamber 65 from the hydraulic oil passage 47 leading to the hydraulic cylinder 333 of the high-speed clutch C3. A pair of annular grooves 68 and 69 are formed on both sides of the land 670 in the valve body 63.A hydraulic oil passage 46 leading to the hydraulic cylinder 332 of the middle speed clutch C2 is connected to an oil passage parallel to the oil passage 61. 70 is branched, and this oil passage '70 is provided with a one-way valve 71 that only allows flow of hydraulic oil from the hydraulic oil passage 46.

Moreover, the oil passage 70 communicates with the oil passage 62 regardless of the switching position of the valve element 63 in the shift shock control valve 60, and
When in the first switching position shown, it also communicates with the open oil passage 13 having the throttle 72 .

Next, the operation of this embodiment will be explained. When shifting up from a middle speed to a high speed when the throttle opening is close to the maximum, in the shift shock control valve 60, the right power of the valve body 63 due to the throttle pressure pi is The valve body 63 has moved to the second switching position by overcoming the left power generated by the operating pressure PH and the spring 66. In this state, medium-high speed foot valve V2
When the valve body 48 moves to the left and the oil passages 3B and 47 communicate with each other, and the hydraulic oil passage 46 and the open oil passage 52 communicate with each other, the pressure oil in the accumulator 55 flows through the throttle 5.
2 and at the same time the accumulator 56
Pressure accumulation starts and engagement of the high speed clutch C8 is started. When the pressure accumulation level of the accumulator 56, that is, the degree of engagement of the high speed clutch C3 reaches the set value, the shift shock control valve 60 adjusts the spring 66 and the operating pressure PH at that time.
The left power of the valve body 63 due to this overcomes the right power of the valve body 63 due to the throttle pressure pt, and the valve body 63 is switched to the first switching position.

Therefore, the accumulator 55 is isolated from the hydraulic oil passage 46, and the pressure oil in the accumulator 55 is discharged via the throttle 12. At this time, although the hydraulic cylinder 332 of the middle speed clutch C2 also exhibits some accumulator-like characteristics due to its rigidity, the amount of oil stored in it is limited to the accumulator 55.
Since the amount is negligible compared to , after the shift shock control valve 60 is switched to the first switching position, the hydraulic oil is discharged through the throttle 51, and the middle speed clutch C2 quickly changes its engaged state. It will be canceled in Therefore, a shock caused by co-engagement between the middle and Takaoka clutches C2 and C3 is avoided.

Here, the high speed clutch C8 when the shift shock control valve 60 switches from its second switching position to its first switching position.
The default value of the operating pressure pH increases in proportion to the throttle opening. Therefore, when the throttle opening is relatively low, the engagement state of the middle speed gear clutch C2 is released relatively quickly, so you do not feel the braking feeling. Since the engaged state of gear clutch C2 is released late, overturning during gear shifting is prevented.

When shifting from a medium gear to a high gear in a light load state with an extremely low throttle opening, or when shifting up from a middle gear to a high gear by releasing the throttle pedal,
The gear shift shock control valve 60 maintains its first switching position, and the engagement pressure of the middle gear clutch C2 is lower than that of the one-way valve 7.
Since a part of the pressure oil is discharged to the oil tank R through the pressure regulator 1 and the throttle 12, the line pressure pt is lower than the line pressure pt defined by the regulator valve rγ. For example, aperture 7
2 is selected to be the same as that of the throttle 37 of the oil passage 38, the engagement pressure of the medium speed clutch C2 at this time is approximately half of the line pressure pt. At this time, the accumulator 55 remains separated from the hydraulic oil path 46, and the amount of oil stored in the hydraulic cylinder 33□ of the middle speed clutch C2 is also small.
Simultaneously with the shift operation of the medium-high speed shift valve V2, the engagement state of the medium speed clutch c2 is released, and a smooth gear change is performed without causing any co-engagement.

When shifting from a high gear to a middle gear (kickdown) with a large throttle opening, the shift shock control valve 60 is in the first switching position shown in the figure in the high gear state, but in the middle-high speed shift. When the valve body 48 of the valve V2 is shifted to the right position as shown in the figure, the accumulator 55 starts accumulating pressure via the one-way valve 71, and the middle speed clutch C2
starts engagement. However, since the oil passage 70 also communicates with the oil tank R via the throttle 72, the middle speed clutch C
The pressure rise of the hydraulic cylinder 332 at 2 is relatively slow. When the operating pressure PH of the high-speed clutch C3 becomes less than a predetermined value, the throttle pressure Pt is large, so the shift shock control valve 60 switches to the second switching position, and the throttle 7
2 is isolated from the oil passage 70. Therefore, after that, the pressure in the hydraulic cylinder 33□ is rapidly increased. In this way, while monitoring the operating pressure PH of the high speed clutch C3,
Since the rise of the engagement pressure of the middle speed clutch C2 is controlled, a good gear shift can be performed without feeling a feeling of mutual engagement or a feeling of racing up.

Here, the timing when the operating pressure P H of the high-speed clutch C3 drops and the shift shock control valve 60 is switched to the second switching position, and the throttle 72 is isolated from the oil passage 70, is when the variable throttle 49
As the throttle pressure pt is lower, the delay is delayed, and as the throttle pressure pt is higher, it is earlier.

Let us assume that the driver is shifting down from a high gear to a middle gear when the load is light, as is often the case when braking a vehicle to a stop when the traffic light at an intersection ahead turns red. In this case, since the throttle pressure pt is almost zero, the shift shock damping valve 1j maintains its first switching position from the start to the end of the shift. Correspondingly, the oil passage 70 remains in communication with the oil tank R via the throttle 72, and the pressure in the hydraulic cylinder 33□ of the middle speed clutch C2 rises relatively slowly, and the maximum value reached is also kept low. . Therefore, the middle, Takaoka clutch C2, C
There is no co-engagement of gears 3 and 3, and smooth gear changes are performed.

In addition, in the above explanation, we have talked about shifting between middle and high speed gears, but when shifting up from a low gear to a middle gear, when the load is light, the middle gear clutch C2 is engaged due to the action of the throttle T2. It will be seen that the combined pressure rises slowly and good results are obtained.

Furthermore, in the shift shock control valve 60, a spring 66 is arranged to bias the valve body 63 toward the closing side, but this spring 66 is responsible for setting the timing of switching, and the spring 66 is responsible for setting the switching timing. 63 may be opened and biased toward (l) 11, but does not constitute a main component of the present invention.

In the embodiment shown in FIG. 2, the engagement pressure of the middle speed clutch C2 when the throttle pedal is not depressed is one step lower because its hydraulic cylinder 332 communicates with the oil tank R via the throttle 72. When the speed change shock control valve is switched to the second switching position by stepping on the throttle pedal, the original line pressure PI acts on the hydraulic cylinder 332, resulting in two-step control. It is also possible to perform analog control in proportion to the speed change shock control valve 74, and the configuration for this purpose will be explained next as a second embodiment.
is interposed between the oil passages 61 and 62. The spool valve body 76 of the speed change shock control valve 74 has a single annular groove 75 on its outer periphery, and when the valve body 76 is in the first switching position on the left side, the valve body 76 is closed between the oil passages 61 and 62. body 76, and when the valve body 76 is in the second switching position on the right side, both oil passages 61.
62 are communicated via an annular groove 75.

Further, the oil passages 61 and 62 are connected by an oil passage 70 that bypasses the shift shock control valve 74, and the oil passage 61 and 62 are connected to each other by an oil passage 70 that bypasses the shift shock control valve 74.
A one-way valve 71 is provided that allows only flow of hydraulic oil from the oil passage 62 toward the oil passage 62 . Furthermore, the oil passage 36 for guiding the throttle pressure pi to the first pilot hydraulic chamber 64 and the oil passage 62 are a one-way valve that only allows flow of hydraulic oil from the throttle 77 and the oil passage 62 to the oil passage 36. It is connected by an oil passage 79 provided with 78.

According to this second embodiment, when the throttle pressure Pt is low and the throttle valve body 76 is in the first switching position, that is, when the engine load is light, the hydraulic oil path 46 communicating with the hydraulic cylinder 332 in the middle speed clutch C2 (See Figure 2)
From there, a part of the pressure oil is discharged into the oil path 36 via the oil path 61, the one-way valve 71, the throttle 77, and the one-way valve 78. 1. Moreover, since the discharge amount is determined by the magnitude of the throttle pressure pi, the engagement pressure of the middle speed clutch C2 is controlled in an analog manner in proportion to the throttle opening.

FIG. 4 shows a third embodiment, in which the engagement pressure of the middle speed clutch C2 is more accurately analog-controlled. That is, the shift shock control valve 80 has a spool valve body 81, a first pilot hydraulic chamber 64 facing the left end of the valve body 81, a second pilot hydraulic chamber 65 facing the right end of the valve body 81, and a first pilot hydraulic chamber 64 facing the left end of the valve body 81. A spring 66 is housed in the chamber 64 and biases the valve body 81 toward the second switching position.
2, and a pressure receiving portion 83 facing the right side at the axial end of the annular groove 82. The open oil channel 85 with the throttle 84 also communicates with the oil channel 61 via the annular ring tn 82 when the valve body 81 is in the first switching position.

According to this third embodiment, the oil passage 61 is always in communication with the annular groove 82, and the engagement pressure of the middle speed clutch C2 acts on the pressure receiving part 83 to move the valve body 81 toward the first switching position. , so that the annular groove 82 communicates with the open oil passage 85. When the annular groove 82 communicates with the open oil passage 85, the engagement pressure decreases and the valve body 81 moves toward the second switching position. Controlled to a predetermined set pressure. Moreover, since the spring 66 is housed in the first pilot hydraulic chamber 64 into which the throttle pressure pt is introduced, the set value of the engagement pressure of the middle speed clutch C2 is proportional to the throttle opening, and as shown in FIG. Compared to control using the throttle 77, this has the advantage of not being affected by oil temperature.

Furthermore, when the engagement pressure of the high-speed clutch C3 reaches a predetermined value, the oil passage 61 of the accumulator 55 is also isolated and does not participate in gear shifting, and at the same time, the return oil passage of the hydraulic cylinder 332 in the middle-speed clutch C2 is isolated. Also, since the path passing through the diaphragm 84 is added to the path passing through the diaphragm 51, the pressure is lowered even more rapidly.

FIG. 5 shows the main part of the fourth embodiment of the present invention,
An open oil passage 88 having a throttle 87 is further connected to the shift shock control valve 60 shown in FIG. This is what I did. In this way, when the working pressure PH of the high speed clutch C3 reaches the predetermined pressure, the pressure oil from the oil passage 61 can also be discharged through the throttle 87, so that the engagement of the middle speed clutch C2 is prevented. The pressure can be lowered more rapidly.

In each of the above embodiments, the accumulator on the clutch side that was previously engaged is isolated from the system in accordance with the operating pressure of the newly engaged clutch, so the amount of oil discharged is drastically reduced. It is possible to design a system that is less affected by the flow resistance of the oil passage. This is especially important in creating a system that is not too sensitive to changes in oil temperature.

Furthermore, when the load is light, the amount of oil stored in the accumulator can be reduced from the beginning. Conversely, when the gear is shifted to the clutch side where the accumulator is provided, for example, in each of the above-mentioned embodiments, when shifting up from a low gear to a middle gear or downshifting from a high gear to a middle gear, the throttle is By the function of 72, the rise of the engagement pressure is slowed down, and smooth gear shifting is achieved.

In the present invention, it is only necessary to variably throttle the amount of oil flowing out from the accumulator 55 into the oil passage 46, and each of the embodiments described above shows an example in which the amount of throttle is maximized. For example, in the first embodiment shown in FIG. 2, if the opening area of the diaphragm 72 is selected to be sufficiently small relative to the diaphragm 51, the oil passage 73 can be connected to the oil passage 46 instead of the oil tank R. You can also do this.

Note that the throttle pressure pt is for both shift valves V1.

The same pressure is applied to V2, each shift shock control valve 60, 74.80, and accumulator 55.58, but this is just for convenience of explanation, and in reality, a modulator valve etc. is interposed in the middle. Therefore, the characteristics of the throttle opening are often changed for each valve.

Furthermore, the present invention can be applied not only to automatic transmissions having a torque converter 1, but also to those having other couplings such as full-conversion or centrifugal automatic clutches, and can also be applied to semi-automatic transmissions. It is possible.

As described above, according to the present invention, the control means for variably reducing the amount of oil from the accumulator on the one friction engagement element side that has been engaged until now is controlled by the newly engaged clutch operating pressure. By providing this, shift shock during low-load shifting is alleviated, and restrictions on the layout design of the oil drain path from the accumulator to the oil tank via the shift valve are also eliminated. Moreover, since an I variable throttle is provided in the oil drainage path from the hydraulic actuating means of the other frictional engagement element, the opening degree of which increases as the engine output increases, the speed change operation is performed in the opposite manner to that described above. Sometimes the engine output can be controlled in a timely manner.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an automatic gear transmission for an automobile with three forward speeds and one reverse speed to which the present invention is applied, and Fig. 2 shows in detail only the main parts of the control circuit of the first embodiment of the present invention. FIG. 3 is a hydraulic circuit diagram of the main parts of the second embodiment of the present invention, FIG. 4 is a hydraulic circuit diagram corresponding to FIG. 2 of the third embodiment of the present invention, FIG. 5 is a main hydraulic circuit diagram of a fourth embodiment of the present invention. 3γ... Throttle, 49... Variable throttle, 5a... Open oil passage, 55... Accumulator, 60, 74.80.
・Shift shock control valve as a control means, 01 to C3...Clutch as a frictional engagement element, M1
~M3...Hydraulic actuation means, V2...Medium-low speed shift valve patent as switching means Applicant: Honda Motor Co., Ltd. Figure 1

Claims (1)

[Claims] a plurality of gear trains having different speed ratios; at least two frictional engagement elements interposed between the gear trains to selectively establish the gear train; and individually for each frictional engagement element; A small (both 2) attached for engaging and operating each frictional engagement element.
a hydraulic power source for supplying oil to each hydraulic power source; and a switching device capable of selectively supplying and discharging pressure oil from the hydraulic power source to and from the hydraulic power source. In the gear transmission, the switching means and the throttle are connected in series between both the hydraulic actuating means and the hydraulic source, an accumulator is connected in parallel to at least one of the hydraulic actuating means, and the accumulator is connected in parallel to at least one of the hydraulic actuating means. In the middle of the oil passage connecting the and the accumulator, there is provided an oil passageway in which oil is drained from the one hydraulic actuating means and oil is supplied to the other hydraulic actuating means.During a gear change, the oil pressure of the other hydraulic actuating means is set to a predetermined value. A control means is provided for controlling the flow resistance of the oil passage to be large or small when the resistance becomes small or large, and the switching means and the oil tank are arranged to drain oil from the other hydraulic actuating means to the oil tank. A speed change control device for a gear transmission, characterized in that a variable throttle is provided in the middle of an open oil path connecting the two to reduce the opening degree as the engine output increases.