JPS5825178B2 - Automatic transmission hydraulic control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a hydraulic control device for an automatic transmission for a vehicle.
Special Q relates to improvements in the shifting characteristics during downsoft.

An automatic transmission for a vehicle that includes a hydraulic torque converter and a gear transmission mechanism equipped with a plurality of frictional engagement devices for obtaining several gears (in this case, the The operation of the frictional engagement device is switched between various types, and the gear transmission mechanism is automatically controlled to a transmission state most suitable for the driving condition of the vehicle at that time.

Switching control of such a frictional engagement device is normally performed by a hydraulic control device, and this hydraulic control device has throttle oil pressure that changes depending on the amount of depression of the accelerator pedal, that is, the intake throttle opening, and vehicle speed ζ. It has a built-in gear shift valve that changes depending on the equilibrium relationship of the vana oil pressure, and selects the gear position of the gear transmission mechanism based on the comparative relationship between the throttle oil pressure and governor oil pressure, that is, the amount of accelerator pedal depression and vehicle speed. It looks like this.

In this case, the speed change valve has a first switching position in which one low gear friction engagement device is connected to the line oil pressure supply oil passage and one high gear friction engagement device is connected to the drain oil passage; The gear friction engagement device is switched between a second switching position in which the gear friction engagement device is connected to the line oil pressure supply oil passage and the low speed gear friction engagement device is connected to the drain oil passage, and In order to provide an appropriate overlap in switching the hydraulic pressure supply to the frictional engagement device for low speed gear and the frictional engagement device for high gear speed, and to perform gear change smoothly, the hydraulic pressure of the frictional engagement device for low speed gear and high gear gear is controlled. A low-speed stage accumulator and a high-speed stage accumulator are connected to the supply oil passages, respectively.

By using a hydraulic control device equipped with such an accumulator, when downshifting from a high gear to a low gear, the hydraulic pressure to the friction engagement device for the high gear (bike clutch) is released and the friction engagement for the low gear is released. It is possible to soften the shift shock by providing an overlap between the operations of supplying hydraulic pressure to the device (low clutch), but even in this case, the degree of overlap, that is, the supply of low clutch hydraulic pressure relative to the discharge of bike clutch hydraulic pressure, If the timing is not set appropriately, there is still a problem in that considerable output shaft torque fluctuations or engine revving occurs, and it is not always possible to obtain a satisfactory downshift feeling.

In order to deal with this problem, when performing downsoft, the high-speed accumulator is controlled by using a control valve controlled by the low clutch hydraulic pressure to detect the point at which the low clutch has finished its idle stroke and the low clutch hydraulic pressure begins to rise substantially. The hydraulic pressure of the bike is lowered to cause slippage in the bike clutch, thereby effectively transferring the transmission of driving force from the bike clutch to the low clutch in a state that causes slippage in both the bike clutch and the low clutch. Furthermore, the point at which the high-speed accumulator has completed its piston travel stroke and its working oil pressure begins to drop further is detected, and a control valve controlled by the bicycle clutch oil pressure is used to reduce the low clutch oil pressure to the full range of the low clutch. A hydraulic control device for an automatic transmission having a control mode that raises the level to a level that causes engagement was filed in 1972 by the same applicant as the present applicant.
This was proposed in Japanese Patent Application No. 52-14749 filed on May 14th.

By the way, when downshifting, the gear ratio of the automatic transmission increases, so when downshifting, the engine must increase the rotational speed corresponding to the ratio of the gear ratio of the high speed gear and the gear ratio of the low gear. In addition, engagement of the low clutch is completed just when this increase in rotational speed is achieved, thereby providing a smooth downshift without shift shock.

The rate of increase in engine speed during downshifting is generally given by the following equation.

Ne=ATt+BTh+CTl In the above formula, Ne is the rate of increase in engine speed, TL is the engine torque, Th is the motorcycle clutch torque, Tl is the low clutch torque, and A, B, and C are each a certain value. It is a coefficient with .

Among these, A and C are positive values, and B is a negative value.

As can be seen from the above equation, the larger the throttle opening, the faster the engine speed increases.

On the other hand, even if the rate of increase in engine speed is the same, for example, when downshifting from 3rd gear with a gear ratio of 1.00 to 2nd gear with a gear ratio of 1.50, if the engine speed before the downshift is Assuming that the rotation speed is 200°rpm,
The engine has to make a 1000 rpm increase up to 3000 rpm, whereas if the engine speed before downshifting is 4000 rpm, the engine will increase by 600 rpm from 4000 rpm.
The rotational speed must be increased by 2000 rpm to m.

Therefore, the absolute value of the increase in rotational speed that the engine should achieve during a downshift depends on the vehicle speed at the time of downsoftening (i.e., the higher the vehicle speed at the time of downshifting, the greater the increase in rotational speed required). It is.

The present invention considers various conditions related to achieving a smooth downshift, as described above, and adapts downshift characteristics to changes in vehicle driving conditions.
It is an object of the present invention to provide a hydraulic control device for an automatic transmission that achieves better downshift performance over a wide range of changes in vehicle operating conditions.

According to the present invention, this object is to provide an automatic system that includes a frictional engagement device for a low gear and a frictional engagement device for a high gear and switches gears by switching the engagement between these two frictional engagement devices. In a hydraulic control device for a gear transmission mechanism for a transmission, a first gear is configured to connect the friction engagement device for a low speed gear to a line oil pressure supply oil passage and connect the friction engagement device for a high gear gear to a drain oil passage. A gear shift that switches between a first switching position and a second switching position in which the high-speed gear friction engagement device is connected to the line oil pressure supply oil path and the low-speed gear friction engagement device is connected to the drain oil path. a low-speed accumulator and a high-speed accumulator connected to the hydraulic pressure supply paths of the low-speed and high-speed frictional engagement devices, respectively; When the hydraulic pressure of the frictional engagement device for the low speed gear increases to a predetermined level that causes the sliding engagement of the frictional engagement device for the low speed gear when the downshift is switched to the switching position, the oil pressure for the high speed gear a first hydraulic pressure control means for reducing the hydraulic pressure of the frictional engagement device to a value that causes slippage in the high-speed frictional engagement device; When the oil pressure decreases to a predetermined level that substantially disengages the high speed friction engagement device, the oil pressure of the low speed friction engagement device is set to a value that causes the low speed friction engagement device to substantially engage. and a control valve that is switched to two different switching positions depending on whether the vehicle speed is below or above a predetermined value, which is controlled by a governor hydraulic pressure that changes depending on the vehicle speed. The hydraulic pressure of the high-speed friction engagement device is modified to two different degrees depending on the vehicle speed by superimposing the oil pressure setting of the high-speed friction engagement device by the first hydraulic pressure control means in the soft state. This is achieved by a hydraulic control device characterized by having a third hydraulic control means.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 is a hydraulic circuit diagram showing one embodiment of a hydraulic control device according to the present invention.

In Fig. Alternatively, the engaged acid is released by discharging the supplied hydraulic pressure.

The speed change valve 3 includes a valve element 5 that is pressed downward in the figure by a compression coil spring 4, and the upper end of the valve element (this is where the throttle oil pressure P[1] is applied from the port 6, and the lower end is connected to the port 6). The governor oil pressure Pgo is applied from 7, and the switching operation is performed in the vertical direction as shown in the figure based on the balanced relationship between the throttle oil pressure and the governor oil pressure.

When the valve element 5 is in the upward switching position, the line hydraulic pressure Pl supplied to the port 8 via the oil passage 9 is supplied from the port 10 to the high clutch 1 via the oil passage 11, and the valve element is in the upward switching position. When the hydraulic pressure is switched downward, the line hydraulic pressure supplied to the port 8 is supplied to the low clutch 2 from the port 12 via the oil passage 13.

Further, when the speed change valve 3 is in the downward switching position, the hydraulic pressure of the high clutch 1 is drained through the oil passage 11, ports 10 and 16, and oil passage 17, and when the speed change valve 3 is in the upward switching position, The oil pressure of low clutch 2 is oil passage 13
, ports 12 and 19 to drain oil passage 20.

Numerals 33 and 34 are a high speed accumulator and a low speed accumulator connected to the oil passages 11 and 13ζ for the high clutch and low clutch, respectively.

Each of these accumulators has a compression coil spring 3
Piston 3 pushed upward in the figure by 5 and 36
7 and 38, and their back pressure chambers 39 and 40.
Hydraulic pressure for back pressure is supplied through oil passages 73 and 80.

A parallel circuit of a throttle element 43 and a check valve 45 is connected to the oil passage 11 for the high clutch, and a parallel circuit of a throttle element 44 and a check valve 46 is connected to the oil passage 13 for the low clutch. .

The control valve 60 is a control valve that controls the supply of back pressure to the high speed accumulator 33 and also controls a part of the hydraulic pressure supply path to the low clutch 2.

The control valve 60 has a valve element 63 pushed upwardly in the figure by a spring 62, and switching of the valve element allows communication or isolation between ports 64 and 65 and ports 85 and 8.
The communication and cutoff between 6 and 6 are controlled.

The valve element 63 is switched by low clutch oil pressure applied to a port 67 via an oil passage 66.

The control valve 61 is a control valve that controls the back pressure drain to the low speed accumulator 34 and also controls a part of the hydraulic pressure supply path to the low clutch.

The control valve 61 includes a valve element 75 which is urged upwardly in the figure by a compression coil spring 74 and which acts to switchly connect port 87 to either port 76 or 88 by switching the valve element. It also controls communication or isolation between the ports 94 and 95.

Port 68 is constantly supplied with line hydraulic pressure, and the line hydraulic pressure is supplied to oil passages 71 and 7 including throttle elements 69 and 70.
2 to ports 64 and 65 of control valve 60, respectively.

Port 88 of control valve 61 is connected to a drain passage 90 that includes a restriction element 89 .

The port 94 of the control valve 61 is connected to an oil passage 96 containing a throttle element 97.
It is connected to the upstream side of the throttle element 44 in the hydraulic pressure supply oil path 13 to the low clutch 2 via the port 9
5 is connected to the oil passage 13 via an oil passage 98 on the downstream side of the throttle element 44 .

A port 93 of the control valve 61 is connected to the upstream side of the throttle element 91 of the drain oil passage 17 in the speed change valve 3 via an oil passage 92 .

The control valve 102 is a control valve that controls the hydraulic pressure supplied to the back pressure chamber 39 of the high speed accumulator 33.

Control valve 102 includes a valve element 104 pushed upwardly in the figure by a compression coil spring 103 so as to control communication and isolation between ports 105 and 106.

Port 107? This is supplied with governor hydraulic pressure, and the governor hydraulic pressure acts to press the valve element 104 downward in the figure.
As will be explained below, when the vehicle speed is below a predetermined value, the valve element 104 is displaced upward in the figure by the action of the spring 103, and the ports 105 and 106 are in communication state Q, and the vehicle speed is increased. When raised above a certain predetermined value, valve element 104 is displaced downwardly in the figure against the action of spring 103, so as to interrupt communication between ports 105 and 106.

The port 106 is connected to the port 64 of the control valve 60 via an oil passage 109 that includes a throttle element 108 .

Next, the operation of the hydraulic control device shown in Fig. 1 is explained in Figs. 2 and 3.
Referring to the figure, the Q difficulty in downshifting will be explained.

Incidentally, FIG. 2 is the same diagram as FIG. 4 in the aforementioned Japanese Patent Application No. 14749/1982.

When the speed change valve 3 is switched from the upper switching position in the figure to the lower switching position, a downshift is started.

By switching the speed change valve 3, the high clutch 1
The oil pressure that was being supplied to the oil line 11, ports 10 and 16
, and begins to be discharged through the drain oil path 17.

At the beginning of such a downshift, the drain passage 17
The oil pressure on the upstream side of the throttle element 91 is sufficiently high, and when this oil pressure acts on the port 93 of the control valve 61 through the oil passage 92, the control valve 61 is switched to the lower position in the figure, and the control valve 61 is switched to the lower position in the figure. Port 87 communicates with drain port 88 .

Further, at the beginning of the downshift, the oil pressure supplied to the low clutch 2 has not yet increased, so the control valve 60 is switched to the upper position in the figure.

As mentioned above, the oil pressure of the high clutch 1 immediately begins to be discharged through the drain oil path 17, but the piston 37 of the accumulator 33 immediately starts upward movement to compensate for the drop in oil pressure, so the oil pressure of the high clutch 1 is reduced as shown in Fig. 2 ζ. The high clutch oil pressure curve A takes a course similar to region α, and remains at a certain accumulator setting oil pressure for a while.

This accumulator setting oil pressure is applied to a parallel circuit of throttling elements 69 and 70 (when control valve 102 is closed) or a parallel circuit of throttling elements 69, 70, and 108 (when control valve 102 is open) from oil path 68. It is determined by the oil pressure supplied to the back pressure chamber 39 through the oil passage 73 and the land difference of the piston 37.

On the other hand, line oil pressure is supplied to the low clutch 2 through an oil passage 13 between the two.

When the low clutch finishes moving through its play area, it reaches point h of the low clutch hydraulic pressure curve B in FIG. 2, and the low clutch hydraulic pressure begins to rise.

Until the low clutch oil pressure reaches point h, the control valve 60 is in the upwardly switched position in the figure, and the oil pressure is supplied to the low clutch 2 mainly through ports 85 and 86 in the control valve 60. When the low clutch oil field reaches point h, the control valve 6 is activated by the oil pressure.
0 is switched downward in the figure, and the communication between ports 85 and 86 is cut off, so that the subsequent supply of hydraulic pressure to the low clutch takes place only through the path passing through the throttle element 44, and therefore from then on The increase in oil pressure to the low clutch becomes gradual, and changes as shown in the γ region in FIG.

Furthermore, by switching the control valve 60 downward, communication between the ports 64 and 65 is cut off, so the supply of hydraulic pressure to the back pressure chamber 39 of the high-speed accumulator 33 is throttled depending on the vehicle speed at that time. As shown in Fig. 2 (the high clutch oil pressure reaches point h), the setting pressure of the accumulator is significantly reduced. It was significantly lower than the corresponding 1 point by 4, and after that β
It varies along the lower levels as shown in the area.

The bike latch is in an engaged state in the α region, but is in a slidingly engaged state in the β region.

Furthermore, the low clutch is in a slipping engagement state in the γ region, and thus a smooth latch switching from the bike clutch to the low clutch is performed in the β and γ regions where both clutches are slippingly engaged. Near the end of the region, the clutch is substantially switched from bike clutch to low clutch engagement.

When the piston 37 in the accumulator 33 reaches the end of its upward movement, the bike clutch oil pressure drops significantly, so the control valve 61 moves upward in the figure due to the drop in the oil pressure acting on the port 93 of the control valve 61. can be switched to

These are the three points in Figure 2.

When the control valve 61 is switched upward, line oil pressure is supplied to the port 87, and this line oil pressure is applied to the back pressure chamber 40 of the accumulator 34, so that the set pressure is in the γ region from the point corresponding to the point. It increases markedly from a relatively low value in the β region to a relatively high value in the β region.

Reliable engagement of the low clutch is achieved at six points along the way.

Thus, in the process in which the bike clutch oil pressure decreases as shown by curve A and the low clutch oil pressure increases as shown in curve B, a smooth downshift from a high speed gear to a low speed gear is achieved. Software is performed.

In addition, the hydraulic circuit diagram shown in Fig. 1 (in this case, 99 is the upshift timing valve when the upshift is performed from the low gear to the high gear, and at the beginning of the upshift, the bike clutch hydraulic pressure is When is still low, the low clutch oil pressure is drained through a drain oil path passing only through the throttle element 100, and after the bike clutch oil pressure reaches a predetermined level, the low clutch oil pressure is drained through the parallel oil path of the throttle elements 100 and 101. This is to adjust the engagement ζ of the bike clutch versus the release timing of the low clutch.

Further, P2 and L applied to the speed change valve 3 are oil pressures applied in the 2nd range and L range, and PdeL is a detent oil pressure applied during kickdown.

As mentioned above, the motorcycle clutch is in a slipping state in the β region of the motorcycle clutch hydraulic pressure curve A shown in FIG. 2, and in the γ region of the corresponding low clutch hydraulic pressure curve B, the motorcycle clutch is in a slipping state. The low clutch is also in a slippingly engaged state.

The oil pressure level in the β region is also controlled depending on whether the control valve 102 is switched upward or downward.

In this case, when the vehicle speed is lower than a certain predetermined value, the control valve 102 reports 105 and 106 are in communication, and therefore, at this time, the back pressure chamber 3 of the high speed accumulator 33
9 is supplied with oil pressure via a parallel circuit of throttle elements 69 and 108, so that the oil pressure level in the β region is kept at a relatively high value.

On the other hand, when the vehicle speed is above a certain predetermined value, the ports 105 and 106 of the control valve 102 are cut off from each other.
Hydraulic pressure is supplied to the back pressure chamber 39 only through the throttle element 69, and therefore the oil pressure level in the β region is a relatively low value.

Looking at this in relation to equation (1) above, when the vehicle speed section and the engine speed before downshifting are higher than a predetermined value, the rate of increase in engine speed Ne required for downshifting is B'J' has a negative coefficient B.
It will be understood that this can be achieved by reducing Th in the term h, that is, the bike clutch transmission torque, that is, by reducing the oil pressure level in the β region.

Thus, in the β region, the high speed accumulator 33
By providing a control element such as the control valve 102 in the path for supplying hydraulic pressure to the back pressure chamber 39 of the vehicle, the downsoft characteristic can be controlled in a better manner in response to changes in vehicle speed.

FIG. 3 is a diagram similar to FIG. 2, but if in the case of FIG. 2 the vehicle speed is higher and the control valve 102 is switched downward, compared to this, the vehicle speed is lower and the control valve 102 is switched downward. shows the downsoft characteristic when is switched upward.

As is clear from the comparison of Fig. 3 with Fig. 2, when the vehicle speed is low, the bike clutch oil pressure in the β region is increased during downsofting, and accordingly, the piston 37 of the high speed accumulator 33 moves faster. and β
It will be appreciated that the elapsed time in the and γ regions is shorter.

Also, as is clear from the above explanation, in the embodiment shown in FIG. 1, during downsoft, the low speed friction engagement device, that is, the low clutch 2, is controlled by the hydraulic pressure, and this hydraulic pressure causes the low clutch to slip. When the oil pressure of the high-speed friction engagement device, that is, the bike clutch 1, rises to a predetermined level (the oil pressure at point h in the graph of Fig. 2), the oil pressure of the high-speed friction engagement device, that is, the bike clutch 1, is the value that causes it to slip (the β region in the graph of Fig. 2). The first hydraulic pressure control means for lowering the hydraulic pressure to the hydraulic pressure of When the oil pressure of the low gear friction engagement device, that is, the low clutch 2, decreases to a predetermined level (the oil pressure at point j on the graph ζ in FIG. The second hydraulic pressure control means for increasing the hydraulic pressure at point d in the graph of the figure is the control valve 61,
The control valve 102 is a control valve that is switched to two different switching positions depending on whether the vehicle speed is below or above a predetermined value. The control valve 60 serves as the first hydraulic pressure control means during downshifting by connecting or not connecting the throttle element 108 in parallel to the throttle element 69 in the oil passage 71 by the control valve.
As a result, the oil pressure of the high-speed friction engagement device, that is, the bike clutch, is reduced to a value that causes the bike clutch 1 to slip, that is, the port 65 of the control valve 60 is shut off, and the pressure is transferred to the back pressure chamber of the high-speed accumulator 33. The oil pressure is supplied through the oil passage 71.
The third hydraulic pressure control means is configured to adjust the hydraulic pressure of the high-speed friction engagement device to two stages depending on the magnitude of the vehicle speed. There is.

FIG. 4 is a diagram similar to FIG. 1 showing another embodiment of the hydraulic control device according to the present invention.

In the embodiment shown in FIG. 4, a control valve 102 having the same structure as the control valve 102 in the embodiment shown in FIG.
' is provided so as to act in the middle of the main oil passage of the high-speed stage accumulator 33.

In the control valve 102', parts corresponding to each part in the control valve 102 are indicated by adding white dashes to the reference numerals of the control valve 102.

By providing the control valve 102', which operates only during downshifting, in the middle of the main oil passage of the high-speed accumulator 33, the same effects as explained in connection with FIGS. 1 to 3 can be obtained. It is clear that

Also, as is clear from the above explanation, the embodiment shown in FIG.
In this case, during downshifting, the oil pressure is controlled by the oil pressure of the low gear friction engagement device, that is, the low clutch 2, and the oil pressure is set at a predetermined level (the oil pressure at point h in the graph of FIG. 2) that causes the low clutch to slip. The first hydraulic pressure control means lowers the hydraulic pressure of the high-speed friction engagement device, that is, the bike clutch 1, to a value that causes it to slip (hydraulic pressure in the β region in the graph of FIG. 2) when The control valve 60 is controlled by the oil pressure of the high-speed friction engagement device during downshifting, and is set at a predetermined level (at a point in the graph of FIG. 2) at which the oil pressure substantially opens the high-speed friction engagement device. 2), the oil pressure of the low gear friction engagement device, that is, the low clutch 2, is increased to a value that substantially engages the low clutch (the oil pressure at point d in the graph of FIG. 2). The second hydraulic control means is a control valve 61, which is controlled to switch according to the governor hydraulic pressure ζ, which changes depending on the vehicle speed, and is switched to two different switching positions depending on whether the vehicle speed is below or above a predetermined value. The valve is control valve 1
02', which includes this control valve and superimposes on the oil pressure setting of the high-speed friction engagement device by the first hydraulic control device during a downshift, and adjusts the oil pressure of the high-speed friction engagement device according to the vehicle speed. The third hydraulic pressure control means for correcting the oil pressure in two stages is composed of a control valve 102', oil passages 120, 121, a throttle element provided in the middle of the oil passage 120, and a check valve 122.

In addition, in the hydraulic control device according to the present invention, the change in vehicle speed Q
Accordingly, the level of the bike clutch oil pressure in the β region is adjusted, and at the same time, the level in the α region also changes.

However, since the bike clutch is essentially in the engaged state in the α region, even if the oil pressure level in the α region changes somewhat due to the adjustment of the oil pressure level in the β region, the second
This does not have any substantial effect on achieving the downshift characteristics as shown in FIG. 3 or FIG.

Although the present invention has been described above in detail with reference to two embodiments, it will be obvious to those skilled in the art that various modifications can be made to these embodiments within the scope of the present invention.

[Brief explanation of drawings]

Fig. 1 is a hydraulic circuit diagram showing one embodiment of the hydraulic control device according to the present invention, and Fig. 2 is a hydraulic pressure and engine rotational speed diagram for explaining the operation of the hydraulic control device shown in Fig. 1 during downshifting. Figure 3 is a graph similar to the graph shown in Figure 2, and is an example of a case where the engine speed during downshift is different from the value shown in Figure 1). FIG. 4 is a hydraulic circuit diagram showing another embodiment of the hydraulic control device according to the present invention. 1... High clutch, 2... Low clutch, 3... Speed change valve, 33... High speed accumulator, 34... Low speed Stage accumulator, 60, 61... Control valve, 99...
...Upshift timing valve, 102,10
2'... Control valve.

Claims (1)

[Claims] 1. For a gear shifting mechanism for an automatic transmission that includes a frictional engagement device for a low gear and a frictional engagement device for a high gear and switches the conversion gear by switching the engagement between these two frictional engagement devices. In the hydraulic control device, a first switching position in which the low-speed gear friction engagement device is connected to a line oil pressure supply oil path and the high-speed gear friction engagement device is connected to a drain oil path; a transmission valve that operates to switch between a second switching position that connects the friction engagement device to the line oil pressure supply oil passage and connects the friction engagement device for low gear to the drain oil passage; A low gear accumulator and a high gear accumulator each connected to a hydraulic pressure supply path of a gear friction engagement device, and a downshift when the shift valve is switched from the second switching position to the first switching position. (This is controlled by the hydraulic pressure of the frictional engagement device for the low gear, and when the hydraulic pressure rises to a predetermined level that causes the sliding engagement of the frictional engagement device for the low gear, the frictional engagement device for the high gear is controlled. a first hydraulic pressure control means for reducing the hydraulic pressure to a value that causes slippage of the frictional engagement device Q for the high speed gear; and a first hydraulic pressure control means for reducing the hydraulic pressure of the frictional engagement device Q for the high speed gear; increasing the hydraulic pressure of the low speed friction engagement device to a value that causes the low speed friction engagement device to substantially engage when the hydraulic pressure of the low speed friction engagement device is reduced to a predetermined level that causes the low speed friction engagement device to be substantially disengaged; It is controlled by two hydraulic control means and a governor hydraulic pressure that changes according to the vehicle speed to determine whether the vehicle speed is below or above a predetermined value (therefore, it includes a control valve that can be switched to two different switching positions). The hydraulic pressure of the high-speed friction engagement device is modified to two different degrees depending on the vehicle speed by superimposing the oil pressure setting of the high-speed friction engagement device by the first hydraulic pressure control means in the soft state. A hydraulic control device comprising a third hydraulic control means.