JPS6049786B2 - Control device for hydraulically operated transmissions for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a hydraulically operated transmission used in an automobile or other vehicle.

Conventionally, this type of device has been provided with a hydraulic motor that is operated by pressure oil supplied from a hydraulic source through a shift valve and that engages clutches and other transmission members that intervene in each predetermined drive train provided for five speed changers. A buffer member such as an accumulator or a timing valve is provided between the hydraulic motor and the shift valve to buffer a sudden increase or decrease in hydraulic pressure when supplying and discharging oil to the hydraulic motor, thereby reducing shock during gear shifting. In this case, for example, a method is known in which back pressure is applied to the accumulator according to the throttle opening, and the accumulator is modulated in the direction of providing a buffering effect on the high oil pressure side as the throttle opening increases. General.

To explain this in more detail, if the back pressure of the accumulator is low, a small increase in pressure when refueling the hydraulic motor will cause the accumulator piston to move against the back pressure, and until this movement is completed, the oil pressure will suddenly increase. The increase in back pressure is buffered, and the pressure change curve in the hydraulic motor becomes as shown in O-A1-B1-C1 in Figure 1. The action area A1-B1 increases sequentially to A2-8, AG set, and thus the pressure change curve becomes 0-A2-C2, O-A3-.

This is because the engine torque during gear shifting increases as the throttle opening increases, and the transmission torque acting on transmission members such as clutches and brakes that are engaged by the hydraulic motor increases, and the hydraulic motor required to engage the transmission members increases. The tightening pressure is Pl
, P2, and P3, the buffer action area is changed to A1-B as the throttle opening increases.
This control is for reducing shift shock by sequentially modulating the pressure to the high side such as 1, A2-B2, A3-B3, and smoothly tightening the transmission member in the buffer action area.

Also, when draining oil from the hydraulic motor, the hydraulic pressure. ``The region that buffers a sudden drop is sequentially modulated to the high pressure side by an increase in back pressure as the throttle opening increases, and the transmission member is released in the buffering region.

However, the engine torque exhibits a characteristic that it increases once as the engine speed increases, then reaches a peak and then decreases, and the shift point near the full throttle opening is on the higher side of the rotation speed than the torque peak. Since the formula to be set is general, in the conventional type described above, even though the engagement pressure of the 4 hydraulic motors decreases from P3 to P4 when changing gears with such a high throttle opening, the buffer action area is A3-8 or above. When the pressure is on the high pressure side, the transmission member cannot be engaged or released in the buffering region, resulting in an inconvenience that the shift shock becomes large.

In order to solve this problem, it is known that the control pressure input to the buffer member is reduced near the full throttle opening, as disclosed in Japanese Patent Application Laid-Open No. 52-14174. A throttle valve for controlling a shift valve that generates hydraulic pressure proportional to the hydraulic pressure over the entire area, and a control valve on its output side are used, and when the input pressure of the control valve is less than a predetermined value, the input pressure is output as is. , when the input pressure exceeds a predetermined value, outputs a hydraulic pressure that decreases as the input pressure increases, so that the control pressure input to the buffer member via the control valve increases the throttle opening to a predetermined high opening. This is designed to show the characteristics of a mountain-shaped change that peaks at a certain degree, but it has the following disadvantages.

In other words, recently there has been a trend to flatten the output characteristics of the engine so that high torque can be obtained over a relatively wide range, and changing the control pressure of the buffer member in a mountain shape as described above will result in a flat engine output. Sometimes it becomes difficult to match the characteristics. SUMMARY OF THE INVENTION An object of the present invention is to provide a device with a simple structure that can make the change characteristics of the control pressure of a shock absorbing member flat in accordance with the flat output characteristics of an engine. A hydraulic motor is provided which is operated by pressure oil supplied through a valve to engage clutches and other transmission members intervening in each predetermined drive train provided in the transmission, and between the hydraulic motor and the shift valve. A buffer member is provided to buffer sudden changes in oil pressure when oil is supplied to and drained from the hydraulic motor, and the buffer member receives control pressure from a throttle member that responds to throttle opening, and is configured to absorb a rise in the control pressure. Accordingly, the throttle member is configured to be modulated in the direction of providing a buffering effect on the high oil pressure side, and the throttle member is configured to include a pair of first and second pressure regulating valves connected in series to the oil pressure source,
The first pressure regulating valve is configured to have an output pressure that increases as the throttle opening increases, and is capable of outputting line pressure input to the throttle member in a region equal to or higher than a predetermined intermediate opening of the throttle opening. In addition, the second pressure regulating valve can output line pressure until the throttle opening reaches a predetermined high opening that is larger than the intermediate opening, and beyond that, the output pressure decreases as the throttle opening increases. It is characterized by being configured in the following format. Next, an example of the implementation of the present invention will be explained with reference to attached sheets FIGS. 2 to 6.

In FIG. 2, reference numeral 1 designates a transmission that performs three forward speeds and one reverse speed. A first speed forward drive train 4-1 which intervenes, a second speed forward drive train 4-2 which intervenes a second speed hydraulic clutch 3-2 which is a transmission member on the input shaft 1a, and a forward drive train 4-2 which is connected to wheels and other loads. 3-speed hydraulic clutch 3 serving as a transmission member on the output shaft 1b
A 3-speed forward drive train 4-3 intervening with the 2-speed forward drive train 4-3 and a reverse drive train 4-R provided in parallel with the 2-speed forward drive train 4-2 to share the 2nd-speed hydraulic clutch 3-2. The two-speed forward drive train 4-2 and the reverse drive train 4-R are selectively established via a selector 5 which is operated to switch between the forward drive side on the left and the reverse drive side on the right in the drawing. .

In the drawing, 6 indicates a directly connected clutch built into the torque converter 2, 7 indicates a one-way clutch interposed in the first speed forward drive train 4-1, and 8 indicates a reverse idler gear interposed in the reverse drive train 4-1.

Each of the aforementioned hydraulic clutches 3-1, 3-2, 3-3 is engaged by supplying pressure oil to the cylinder-type hydraulic motors 3a-1, 3a-2, 3a-3 at the end, and these hydraulic clutches The supply of pressure oil to the motors 3a-1, 3a-2, and 3a-3 is controlled by a hydraulic circuit 9 shown in FIG. 3, for example. The hydraulic circuit 9 includes a manual valve 12 connected to a hydraulic source 10 via a first oil passage 11-1, and a shift valve 13 connected to the manual valve 12 via a second oil passage 11-2. , the shift valve 13 is a pair of first and second shift valves 13-1, 13 connected via an intermediate third oil passage 11-3.
-2, the second shift valve 1
Hydraulic motors 3a-2 and 3a-3 of 2nd and 3rd speed hydraulic clutches 3-2 and 3-3 were respectively connected to the fourth and fifth oil passages 11-4 and 11-5 derived from 3-2. .

Each shift valve 13-1, 13-2 has a sixth oil passage 11-6 and an auxiliary passage 11-6a from the governor 14 at one end, that is, the right end.
The governor pressure according to the vehicle speed is applied via the spring 13a at the left end.
-1 and 13a-2 and a throttle pressure corresponding to the throttle opening from the throttle valve 15 through the seventh oil passage 11-7. When the shift valve 13-1 moves from the first gear position on the right side to the second gear position on the left side, the second oil passage 11-2 is connected to the first oil passage 11-1 in the automatic shift D range of the manual valve 12. is connected to the fourth oil passage 11-4 via the third oil passage 11-3 and the second shift valve 13-2,
By supplying pressure oil to the hydraulic motor 3a-2 of the 2nd speed hydraulic clutch 3-2, this is engaged and the 2nd speed forward drive train 4-2 is engaged.
is established, and then the second shift valve 13-2 moves from the second gear position on the right side to the third gear position on the left side, and the third oil passage 11
-3 is connected to the fifth oil passage 11-5, and this is connected by supplying pressure oil to the hydraulic motor 3a-3 of the third-speed hydraulic clutch 3-3, thereby establishing the third-speed forward drive train 4-3. I did it like that. In the drawing, reference numeral 16 indicates a servo valve for forward/reverse switching connected to the selector 5, and the servo valve 16 is connected to the first oil passage 11- in the D range of the manual valve 12.
By supplying pressure oil to the eighth oil passage 11-8 connected to 1 and the spring 16a, the selector 5 is slid to the left forward position to switch to the forward side, and the second-speed hydraulic clutch 3-2 is engaged. At the same time, it operates to establish the second-speed forward drive train 4-2, and connects the eighth oil passage 11-8 to the front hydraulic clutch 3-1.
The front hydraulic clutch 3-1 is connected to the ninth oil passage 11-9 leading to the hydraulic motor 3a-1, and operates to engage the front hydraulic clutch 3-1.

Here, the hydraulic motor 3a of the front hydraulic clutch 3-1
-1 is the hydraulic motor 3a-3 of the 3rd speed hydraulic clutch 3-3
The control valve 17, which is closed when pressure oil is supplied to the engine, is inserted into the ninth oil passage 11-9 so that pressure oil is supplied until the 3-speed forward drive train 4-3 is established. When the 2nd speed forward drive train 4-2 is established, even though the front hydraulic clutch 3-1 is engaged, the one-way clutch 7 intervened in the 1st speed forward drive train 4-1 and the power is transmitted through the drive train 4-1. Not done.

Incidentally, the servo valve 16 is connected to the first oil passage 11-1 in the reverse R range of the manual valve 12.
By supplying pressure oil to the shaft path 11-10, the selector 5 is slid to the right reverse position in order to switch to the reverse side against the spring 16a, and the tenth oil path 11-10 is connected to the shift valve 13. Hydraulic motor 3a of 2-speed hydraulic clutch 3-2 via
-2 and operates to establish a reverse drive train 4-R.

In the drawings, 18-1 and 18-2 indicate the fourth and fifth oil passages 11-4,
11-5 shows an accumulator as a buffer member connected to each other, and a first
The control pressure from the throttle member 19 which responds to the throttle opening is applied via the plow passages 11-12.

The throttle member 19 has first and second pressure regulating valves 19-1 interposed in series between the eighth oil passage 11-8 and the twelfth oil passage 11-12 via the B-th oil passage 11-13. , 19-2, with the second pressure regulating valve 19-2 on one side coaxial with the first pressure regulating valve 19-1, that is, on the left side in the drawing, and the second pressure regulating valve 19-2 on the right side as the throttle opening increases. 1 Pressure regulating valve 19-1
In the illustrated example, the first throttle valve 15-1 on the upstream side constituting the throttle valve 15 is also used as the response member.

The first pressure regulating valve 19-1 is configured such that its opening degree increases as it moves to the left, and the first throttle valve 15-1
The right end double inner and outer first spring 1 interposed between 1 and 1.
9a and 19b connect the left opening side and the second pressure regulating valve 1.
The second spring 19c at the left end interposed between the first throttle valve 15-2 and the first throttle valve 15-2 is biased toward the right closing side by the second spring 19c interposed between the first throttle valve 15-2 and the first throttle valve 15-2. 1 is moved to the left, first the inner spring 19a of the first spring, then the outer spring 19
b are sequentially compressed, and the B oil passage 11-13 on the downstream side
The output pressure generated at The output pressure reaches the line pressure given to the eighth oil passage 11-8 and remains constant thereafter, and eventually the output pressure changes as shown by line a in FIG.

The second pressure regulating valve 19-2 is configured such that its opening degree is increased as it moves to the right, and the second spring 19c causes the left side to close, and the third spring 19d at the left end causes the right side to open. The difference in elastic force between the opening side and the closing side is normally caused by the third spring 19d and the second spring 19c. 12 downstream above the corresponding maximum value
A hydraulic pressure equal to that of the upstream oil passage B 11-13 is output to the oil passage 11-12, but as the throttle opening increases, the throttle opening becomes higher than the intermediate opening. When the first throttle valve 15-1 contacts the first pressure regulating valve 19-1 and moves it to the left, the elastic force of the second spring 19c increases to reach a predetermined high opening, e.g.
When the difference in the elastic force falls below the maximum value at 518 degrees of opening, the hydraulic pressure on the downstream side gradually decreases, and the control pressure eventually output to the first glazing path 11-12 is shown by line b in Fig. 4. As a result, a flat trapezoidal change characteristic is exhibited in the constant range from the intermediate opening degree to the high opening degree. In addition, as shown in Figure 7, the second
Even if the eighth oil passage 11-8 is connected to the pressure regulating valve 19-2 and the twelfth oil passage 11-12 is connected to the first pressure regulating valve 19-1, the second specific oil 4th on road 11-13
As shown by line c in the figure, a constant hydraulic pressure is generated up to a predetermined high opening of the throttle and then decreases, and the first pressure regulating valve 19-
Similarly to the above, the control pressure shown by line b in FIG.

Therefore, when refueling the hydraulic motors 3a-2 and 3a-3 of the 2nd and 3rd speed hydraulic clutches 3-2 and 3-3, the accumulator 1
The pressure increase buffering area where the pistons 18a-1 and 18a-2 of 8-1 and 18-2 move against the control pressure is the low and medium opening area where the control pressure increases as the throttle opening increases. Similarly to the above conventional type, A1-Bl, A2-
As shown in B2 and A3-B3, the pressure is modulated to the high pressure side as the throttle opening increases, but in the high opening range of the throttle opening where the control pressure decreases, the buffer action area is A3-B3.
The voltage is modulated to the lower pressure side, as shown in A4-B4 in FIG. Moreover, the pressure drop characteristics when draining oil from each hydraulic motor 3a-2, 3a-3 are as shown in FIG. 6, and the pressure drop is buffered by pushing out the accumulator pistons 18-1, 18-2 by the control pressure. As the throttle opening increases, the areas A″1-B″1, A″2-B″2, A″3-B″3
The pressure is sequentially modulated to the high pressure side as shown in FIG.
It is modulated to the low pressure side as shown in 4-B''4.

In the drawing, 20-1 and 20-2 are the fourth and fifth oil passages 11-4,
Orifices 21-1, 21-2 interposed in 11-5
One-way valves 22-1, 22-2 are provided in parallel to the hydraulic motors 3a-2, 3a-3 to allow oil to flow when draining oil.
When the second shift valve 13 is moved to the 3rd or 2nd speed position, the oil drain passages 11-14 and 11-15 are connected to the fourth and fifth oil passages 11-4 and 11-5, respectively. Orifice 2
3-1 and 23-2 are parallel switching valves that are opened in the low throttle opening range by the control pressure to hasten the pressure drop when draining oil from each of the four hydraulic motors 3a-2 and 3a-3. It works as expected.

24 is a control valve that controls the supply of pressure oil to the direct coupling clutch 6 provided in the torque converter 2; 25 is a control valve that regulates the pressure oil from the hydraulic source 10 to a line pressure corresponding to the -stator reaction force of the torque converter 2; 1 oil passage 11-1 and the torque converter 2.

Next, the operation will be explained by taking as an example the shift from 2nd speed to 3rd speed in the D range of the manual valve 12.

Here, a second shift valve 13 that changes gears from 2nd speed to 3rd speed
-2, the throttle pressure and governor pressure applied to both ends cause movement to the 3rd gear position on the high vehicle speed side, that is, on the high rotation side of the engine, as the throttle opening increases, and the engine torque and therefore 3rd gear The torque to be transmitted via the hydraulic clutch 3-3 also increases, and the engagement pressure of the hydraulic motor 3a-3 required to engage the hydraulic clutch 3-3 also increases to Pl, P2, P3.
However, in a predetermined high opening range of the throttle opening, the gear shift is performed in a high rotational range of the engine where the engine torque passes its peak and decreases, so the engagement pressure of the hydraulic motor 3a-3 is It decreases from P3 to P4.

Here, in recent engines, the torque peak is flattened, and the speed is changed in a rotation range that outputs the maximum torque over a certain range from the intermediate throttle opening, and the tightening force is P3 in this range. will be maintained.

On the other hand, the buffering area for the pressure increase when refueling the hydraulic motor 3a-3 due to the movement of the second shift valve 13-2 to the 3rd speed position is affected by the engagement pressure Pl as the throttle opening increases.
, P2, P3 according to A1-Bl, ~-B2, ~-B3
The pressure increases sequentially as in A4-B4 as the engagement pressure decreases to P4 in the high throttle opening range, and the engagement pressure reaches its maximum in a certain range from the middle throttle opening. As the value P3 is maintained, the buffering area is also maintained at A3 due to the flat characteristic of the control pressure described above, and thus the third speed hydraulic clutch 3-3
is smoothly fastened in the buffer action region at any throttle opening, and does not cause a large shift shock.

In addition, the buffering area for the pressure drop when oil is drained from the hydraulic motor 3a-2 of the 2nd speed hydraulic clutch 3-2 due to the movement of the second shift valve 13-2 to the 3rd speed position is also affected by the increase in throttle opening. As the release pressure that causes the hydraulic clutch 3-2 to release increases sequentially as P''1, P''2, P''3, A''1-B''1, A''2-B''2, A″3-B″
3, the pressure increases sequentially, and when the release pressure is maintained at P''3 in a certain range from the middle throttle opening, it is maintained at A''3-B''3, and then when the throttle opening exceeds the range When the release pressure drops to P''4 in the high opening range, the pressure becomes low as shown in A''4-B''4, and smooth release of the second-speed hydraulic clutch 3-2 is always provided in the buffer action area.

When shifting from 3rd speed to 2nd speed, the 2nd speed hydraulic clutch 3-2 is engaged and the 3rd speed hydraulic clutch 3-3 is simultaneously released in the buffer action region, which prevents a large shift shock in the high throttle opening region. will not occur.

Further, when shifting from 1st to 2nd speed, the front hydraulic clutch 3-1 is always engaged, and the 2nd speed hydraulic clutch 3 is engaged by moving the first shift valve 13-1 to the 2nd or 1st speed position.
-2 is engaged or released; however, in this case as well, the second-speed hydraulic clutch 3-2 is always engaged or released within the pressure change buffering region, thereby reducing the shift shock.

In addition, when shifting in the high opening range of the throttle opening, the 2nd or 3rd speed hydraulic clutch 3-2 on the side to be engaged is
, 3-3, when the hydraulic motors 3a-2, 3a-3 are filled with pressure oil, they rotate at high speed and generate a large force in the fastening direction due to centrifugal force, which intensifies the shock. Therefore, it is desirable that the control pressure generated by the throttle member 19 in the high opening range of the throttle be further reduced in consideration of this force. 9 Also, in the above embodiment, the second pressure regulating valve 19-2 of the throttle member 19
Although it is made to respond to the throttle opening via the first pressure regulating valve 19-1, it is also possible to make it respond directly to the throttle opening.

Furthermore, in the above embodiment, the accumulators 18-1 and 18-2 were used as buffer members, but this could be used, for example, in the eighth embodiment.
It is also possible to construct the timing valve 26 shown in the figure. The timing valve 26 is connected to the fourth and fifth oil passages 11.
-4 and 11-5, and the hydraulic pressure on the downstream side is quickly transferred to the left end closing side through the large diameter first orifice 26a when refueling the hydraulic motors 3a-2 and 3a-3. It operates to buffer sudden changes in the oil pressure until the oil pressure is applied to the opening side at the right end through the small-diameter second orifice 26b, and from the throttle member 19 to the first? As the control pressure applied to the opening side via the path 11-12 changes, the buffering region is also modulated between the high pressure side and the low pressure side, resulting in the same operation as in the above embodiment.

As described above, according to the present invention, the control pressure from the throttle member input to the buffer member is maintained at the line pressure, which is the peak value, in a certain range of the throttle opening from a predetermined intermediate opening to a predetermined high opening. As a result, the engine torque peak becomes flat, and the hydraulic motor engagement pressure and release pressure during gear shifting no longer fluctuate within the throttle opening range. Therefore, the buffer member is also maintained in a state where it produces a buffering effect on the high pressure side, and in conjunction with the change in the buffering area of the buffer member due to changes in the control pressure before and after this range, the buffering effect is maintained smoothly over the entire throttle opening range. The throttle member can be configured to have two pressure regulating valves that operate with opposite characteristics in response to changes in the throttle opening.
It has the advantage of having a simple structure and being inexpensive.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the characteristics of a conventional device, FIG. 2 is a diagram of an example of a transmission to which the device of the present invention is applied, FIG. 3 is a hydraulic circuit diagram of an example of the device of the present invention, and FIG. The figure is a diagram showing the characteristics of the throttle member, Figures 5 and 6 are diagrams showing the pressure increase characteristics and pressure drop characteristics due to the buffer member, and Figure 7 is a diagram showing other embodiments of each throttle member. Circuit diagram, FIG. 8 is a circuit diagram showing another embodiment of the buffer member. 1...Transmission, 3-1, 3-2, 3-3...
...Transmission member, 3a-1, 3a-2, 3a-3...
・Hydraulic motor, 4-1, 4-2, 4-3... Drive train, 10... Hydraulic source, 13... Shift valve, 18-1, 18- 2,26...Buffer member.

Claims (1)

[Scope of Claims] 1. A hydraulic motor is provided which is operated by pressure oil supplied from a hydraulic source through a shift valve to engage clutches and other transmission members intervening in each predetermined drive train provided in the transmission, and A buffer member is provided between the hydraulic motor and the shift valve to buffer sudden changes in oil pressure when oil is supplied to and discharged from the hydraulic motor, and the buffer member is controlled by a throttle member that responds to throttle opening. Under pressure,
The control pressure is modulated in the direction of providing a buffering effect on the high hydraulic pressure side as the control pressure increases, and the throttle member is connected in series to the hydraulic pressure source, and a pair of first and second pressure regulating valves are provided. The first pressure regulating valve has an output pressure that increases as the throttle opening increases, and outputs line pressure that is input to the throttle member in a region equal to or higher than a predetermined intermediate opening of the throttle opening. The second
The pressure regulating valve is configured to be able to output line pressure until the throttle opening reaches a predetermined high opening that is larger than the intermediate opening, and beyond that, the output pressure decreases as the throttle opening increases. A control device for a hydraulically operated transmission for a vehicle, characterized by: 2. A second pressure regulating valve is disposed on one side coaxially with the first pressure regulating valve, and a throttle response member that is displaced toward the first pressure regulating valve as the throttle opening increases is disposed on the other side. Displacing the first pressure regulating valve toward the second pressure regulating valve increases its opening degree, and displacing the second pressure regulating valve toward the first pressure regulating valve increases its opening degree. Further, a first spring is interposed between the first pressure regulating valve and the response member, and a second spring is interposed between the two pressure regulating valves. A third spring is provided that urges the pressure valve toward the first pressure regulating valve, and the third spring is made stronger than the second spring so that the difference in elastic force is determined by the output pressure of the second pressure regulating valve. The pressing force to the closing side is made to exceed a maximum value corresponding to the line pressure, and the response member contacts the first pressure regulating valve at a throttle opening between the intermediate opening and the high opening. In areas beyond that, the first
The pressure regulating valve is directly pushed toward the second pressure regulating valve by the response member, and the elastic force of the second spring increases due to this pushing, so that the throttle opening exceeds the high opening. The control device for a hydraulically operated transmission for a vehicle according to claim 1, wherein the difference in elastic force between the third spring and the second spring is less than the maximum value. .