JPS63176742A - Hydraulic controller for belt type continuously variable transmission for vehicle - Google Patents

Abstract

PURPOSE:To obtain a good speed change response by providing a bypath having a switching valve between respective hydraulic paths for feeding line pressure oil to primary and secondary pulleys and intake/discharge oil paths for a speed change control valve, thereby feeding/discharging line pressure quickly. CONSTITUTION:A spool 68 in a speed change control valve 44 is switched to the right and left so as to feed/discharge a predetermined line oil pressure to hydraulic cylinders 26, 28 for primary and secondary pulleys 20, 22 of a continuously variable transmission (CVT) thus making a CVT control. Bypaths 110, 112, 114, 116 are provided through switching valves 118, 120 between respective oil paths 29, 30 to hydraulic cylinders of respective pulleys and suction/ discharge oil paths 50, 52 for the speed change control valve 44. When the speed change ratio of CVT is increased, the switching valve 118 is operated to feed line pressure quickly to the hydraulic cylinder 26 for the primary pulley 20 so as to achieve a good and quick speed change response.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a hydraulic control system for a belt-type continuously variable transmission for a vehicle, and in particular, to precise shift control and rapid shift responsiveness by minute opening control '411 of a shift control valve. It is related to technology that achieves both.

Prior Art A pair of primary variable pulleys and a secondary variable pulley provided on the primary rotating shaft and the secondary rotating shaft, respectively, and a power transmission belt that is wound around the pair of variable pulleys to transmit power; 2. Description of the Related Art A belt-type continuously variable transmission for a vehicle is known that includes a pair of primary and secondary hydraulic cylinders that respectively change the effective diameters of a pair of variable pulleys.

As a hydraulic control device for such a vehicle belt-type continuously variable transmission, for example, as described in Japanese Patent Application No. 61-37571 previously filed by the applicant, (a) a hydraulic cylinder on the drive side; (b) a first pressure regulating valve that regulates the pressure of hydraulic oil supplied from a hydraulic source to obtain a first line hydraulic pressure in order to obtain the thrust required for the first line hydraulic pressure; By supplying hydraulic oil to one of the primary hydraulic cylinder and the secondary hydraulic cylinder and simultaneously causing hydraulic oil in the other to flow out, the effective diameters of the primary variable pulley and the secondary variable pulley are changed, and the stepless A speed change control valve that adjusts the speed ratio of the transmission; and a second pressure regulating valve that regulates the pressure of the hydraulic oil flowing out to a second line hydraulic pressure lower than the first line hydraulic pressure, and the actual speed ratio or input shaft rotation speed is adjusted according to the driving condition of the vehicle. There is a type in which the speed change control valve is controlled so as to match the determined target speed ratio or target input shaft rotation speed.

Problems to be Solved by the Invention Incidentally, such conventional hydraulic control devices require minute opening control of the speed change control valve when adjusting the speed ratio in order to improve control accuracy during steady state, and also require In order to improve the shift responsiveness of the shift control valve, a large opening degree of the shift control valve is required, but it has been difficult to satisfactorily satisfy both of these demands.

For example, in order to obtain a large opening for a speed change control valve, the distance the valve element must move must be increased, but in this case the sliding surface becomes larger and the hysteresis of the valve also tends to increase. This becomes an obstacle to opening degree control.

Means for Solving the Problems The present invention has been made to solve the above problems, and its gist is that a pair of A primary side variable pulley and a secondary side variable pulley, a transmission belt that is wound around the pair of variable pulleys to transmit power, a pair of primary side hydraulic cylinders that change the effective diameter of the pair of variable pulleys, and a secondary side variable pulley. In a vehicle belt-type continuously variable transmission equipped with a downstream hydraulic cylinder, first line oil at a predetermined pressure is supplied to one of the primary hydraulic cylinder and the secondary hydraulic cylinder, and at the same time, hydraulic oil in the other is supplied. A hydraulic control device of a type having a speed change control valve that adjusts the speed ratio of the continuously variable transmission by changing the effective diameter of the primary variable pulley and the secondary variable pulley by letting the fluid flow out,
(al) a bypass oil passage provided in parallel with the speed change control valve and for draining the hydraulic oil in the primary side hydraulic cylinder and/or the secondary side hydraulic cylinder; (b) provided on the bypass oil passage; When the speed change control valve rapidly supplies first line oil to one of the primary side hydraulic cylinder and the secondary side hydraulic cylinder, and at the same time rapidly drains the hydraulic oil in the other side, the valve is opened, and the hydraulic oil in the other side is opened. and a bypass control valve for causing the oil to flow out through the bypass oil passage.

Operation and Effects of the Invention With this arrangement, when the speed change control valve rapidly supplies the first line oil to one of the primary hydraulic cylinder and the secondary hydraulic cylinder, and at the same time rapidly causes the hydraulic oil in the other cylinder to flow out, Since the bypass oil passage is opened by the bypass control valve, the hydraulic oil in the hydraulic cylinder can easily and quickly flow out. Therefore, the speed change control '<111 valve can be designed mainly to improve control accuracy during steady state, and does not require a large opening to improve speed change response during transient times. High control accuracy can be obtained in ratio control, and at the same time, high speed change responsiveness can be obtained.

Here, the bypass oil passage preferably includes a first speed increasing bypass oil passage for supplying first line oil to the primary side hydraulic cylinder, and a first speed increasing bypass oil passage for draining the hydraulic oil in the secondary side hydraulic cylinder. and a second speed-increasing bypass oil passage.

Further, the high-pass oil passage preferably includes a first deceleration bypass oil passage for supplying the secondary side hydraulic cylinder/first line oil, and a first deceleration bypass oil passage for supplying the hydraulic oil in the primary side hydraulic cylinder. It consists of a second deceleration bypass oil passage for causing the oil to flow out.

Preferably, the bypass control valve is a speed increasing bypass control valve that simultaneously opens and closes the first station increasing bypass oil passage and the second station increasing bypass oil passage; 8 speed 1fl bypass oil passage and 2nd
A deceleration bypass system that simultaneously opens and closes the deceleration bypass oil passage? It is a fll valve.

Further, as the bypass control valve, an on-off valve that is controlled in two stages, a fully closed state and a fully open state, or a linear control valve that has a flow cross-sectional area that is continuously changed, is preferably adopted. Ru. In the latter case, an overlapping valve with a relief zone is desirable.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, the output of an engine 10 installed in a vehicle is transmitted via a clutch 12 to a primary rotating shaft 16 of a belt-type continuously variable transmission [14].

The belt type continuously variable transmission 14 includes a primary rotating shaft 16 and a secondary rotating shaft 18, and a primary variable pulley 20 with a variable effective diameter attached to the primary rotating shaft 16 and the secondary rotating shaft 18. and the secondary variable pulley 22, the transmission belt 24 that is wound around the primary variable pulley 20 and the secondary variable pulley 22 to transmit power, and the effectiveness of the primary variable pulley 20 and the secondary variable pulley 22. The primary hydraulic cylinder 26 and the secondary hydraulic cylinder 28 whose diameters are changed are (III).The primary hydraulic cylinder 26 and the secondary hydraulic cylinder 28 are formed to have the same pressure receiving area, The outer shapes of the primary variable pulley 20 and the secondary variable pulley 22 are the same, so that the belt type continuously variable transmission 14 is small.
The primary variable pulley 20 and the secondary variable pulley 22
The fixed rotating bodies 31 and 32 are fixed to the primary rotating shaft 16 and the secondary rotating shaft 18, respectively, and the fixed rotating bodies 31 and 32 are fixed to the primary rotating shaft 16 and the secondary rotating shaft 18, respectively. y? may be provided between the fixed rotating bodies 31 and 32. :, and movable rotating bodies 34 and 36 forming W.

The output from the secondary rotating shaft 18 of the belt-type continuously variable transmission 14 is transmitted to a drive component of the vehicle via an auxiliary transmission, a differential tooth width device, etc. (not shown).

A hydraulic control circuit for operating the vehicle power transmission device configured as described above is configured as described below. That is, the oil tank 38 passes through a return path (not shown).
The hydraulic oil flowing into lff is sucked into the oil pump 42 via the strainer 40 and the suction oil passage 41, and is then sucked into the first line oil passage 50 connected to the input boat 4G of the speed change control valve 44 and the first pressure valve 48. be pumped to. The oil pump 12 is driven by the engine 11 (11) via a drive shaft (not shown). The first pressure regulating valve 48 controls the first line oil pressure PN by causing a part of the hydraulic oil in the first line oil passage 50 to flow out to the second line oil passage 52 in accordance with a first drive signal MDI, which will be described later.

This second line oil passage 52 is connected to the first discharge port 54 and the second discharge port 56 of the speed change control valve 44 and the second pressure regulating valve 5.
8, respectively. This second pressure regulating valve 58 operates in a second line oil passage 5 according to a second drive signal VD2, which will be described later.
The second line oil pressure Pp, which is relatively lower than the first line oil pressure Pe, is controlled by causing a part of the hydraulic oil in the second line to flow out to the drain oil passage 60. The first pressure regulating valve 48 and the second pressure regulating valve 58 are constructed from so-called electromagnetic proportional relief valves.

The speed change control valve 44 is a so-called proportional control solenoid valve, and is connected to the human-powered boat 46, the first discharge port 54, and the second discharge port 54.
The discharge boat 56 is connected to a pair of first output capotros 2 and second output capotros 4, which are connected to the primary side hydraulic cylinder 26 and the secondary side hydraulic cylinder 28 via oil passages 29 and 30, respectively. A cylinder bore 66 formed in the valve body 65 so as to communicate with each other, a spool valve element 68 slidably fitted into the cylinder bore 66, and a cylinder extending from both ends of the spool valve element 68 toward a neutral position. A pair of first springs 70 and a second spring 72 are provided at both ends of the spool valve 68 to hold the spool valve 68 in a neutral position by being biased. It includes a first electromagnetic solenoid 74 and a second electromagnetic solenoid 76 that are continuously moved against the urging force of the spring 72 or the first spring 70. On the spool valve 68, four lands 78, 80, 82, 84 are formed sequentially from one end, and a pair of lands 80 and 82 located in the middle are arranged so that the spool valve 68 is neutral as shown in the figure. When in position, it is formed at the same position as the first output capotro 2 and the second output capotro 4 in the axial direction of the spool valve element 68. Further, the inner peripheral surface of the cylinder bore 66 is located at a position facing the pair of lands 80 and 82 when the spool valve element 68 is in the neutral position, that is, the first output capotro 2 and the second output capotro 4. A pair of first annular grooves 86 and second annular grooves 88 having a width slightly larger than the lands 80 and 82 are formed at positions where the first annular grooves 86 and the second annular grooves 88 open into the inner circumferential surface of the cylinder bore 66 .

The first annular groove 86 and the second annular groove 88 are connected to the land 80.
and 82 to form a constriction whose flow cross-sectional area changes continuously in order to control the flow of hydraulic oil.

As a result, when the spool valve 68 is in the neutral position, the first output capotro 2 and the second output capotro 4
are evenly communicated with the input port 46 and the discharge boat 54, 56 with a small circulation area, and an amount of hydraulic oil sufficient to replenish leakage is supplied to the primary hydraulic cylinder 26 and the secondary hydraulic cylinder 28, Also, a small amount of hydraulic oil is drained from the drain boat 54,56.

However, as the spool valve element 68 is moved from the neutral position in its uniaxial direction, for example, in the direction approaching the second electromagnetic solenoid 76 (i.e., rightward in the figure), the first output capotro 2 and the first discharge While the flow cross-sectional area with the port 54 is continuously increased, the flow cross-sectional area between the second output port 4 and the input port 46 is continuously increased. The working oil pressure output to the side hydraulic cylinder 26 is lower than the working oil pressure output from the second output capotro 4 to the secondary side hydraulic cylinder 28. For this reason, the balance between the thrust forces of the primary hydraulic cylinder 26 and the secondary hydraulic cylinder 28 in the belt-type continuously variable transmission 1114 is disrupted, so that while hydraulic oil flows into the secondary hydraulic cylinder 28, the primary hydraulic cylinder 26 The hydraulic oil inside flows out, and the speed ratio e (rotational speed N of the secondary rotating shaft 18, uL/rotating speed N of the primary rotating shaft 16, n) of the belt type continuously variable transmission 14 becomes small.

On the other hand, as the spool valve 68 is moved from the neutral position toward the first electromagnetic solenoid 74, that is, to the left in the figure, the cross-sectional area of flow between the first output capotro 2 and the human-powered boat 46 decreases. is continuously increased, while the flow cross-sectional area between the second output capotro 4 and the second discharge boat 56 is increased. Hydraulic pressure is from the second output coupler.
The hydraulic pressure is higher than the working pressure output from the trolley 4 to the secondary hydraulic cylinder 28. For this reason, the belt type continuously variable transmission 1
4, the balance between the thrust forces of the primary hydraulic cylinder 26 and the secondary hydraulic cylinder 28 is disrupted, so while the hydraulic oil in the secondary hydraulic cylinder 28 flows out, the hydraulic oil flows into the primary hydraulic cylinder 26. The speed ratio e of the belt type continuously variable transmission 14 increases. In this way, the speed change control valve 4
4 has a switching valve function that supplies high-pressure hydraulic oil to one of the hydraulic cylinders 26 and 28 and low-pressure hydraulic oil to the other, and a flow control valve function that continuously adjusts the flow rate of the hydraulic oil. That's what I'm doing.

In this embodiment, a pair of first speed increasing bypass oil passages 110 and a second increasing bypass oil passage 112 are arranged in parallel with the speed change control valve 44, and a pair of 1m-th passage bypass oil passages 114 are arranged in parallel with the speed change control valve 44.
A second deceleration bypass oil path 116 is provided, and a speed increase bypass control valve 118 is inserted in the pair of speed increase bypass oil paths 110 and 112, and a speed increase bypass oil path 118 is inserted in the pair of speed increase bypass oil paths 110 and 112. A deceleration bypass control valve 120 is inserted at 114 and 116. That is, the first
The station expansion bypass oil passage 110 and the second speed increase bypass oil passage 112 are located between the connection oil passage 29 and the first line oil passage 50,
and are connected between the connection oil passage 30 and the second line oil passage 52, and during rapid speed-up changes, the hydraulic oil in the first line oil passage 50 (first line oil) is used for the first speed-up. By supplying the hydraulic oil to the primary hydraulic cylinder 26 through the bypass oil passage 110 and flowing out of the secondary hydraulic cylinder 28 to the second line oil passage 52 through the second expansion bypass oil passage, the hydraulic oil is rapidly transferred to the primary side. The effective diameter of the variable pulley 20 is increased, and the effective diameter of the secondary variable pulley 22 is decreased. In addition, the first deceleration bypass oil passage 114
The second deceleration bypass oil passage 116 is connected between the connection oil passage 30 and the first line oil passage 50, and between the connection oil passage 29 and the second line oil passage 50.
The line oil passages 52 are connected to each other, and during a rapid deceleration shift, the first line oil is supplied to the secondary hydraulic cylinder 28 through the first deceleration bypass oil passage 114 and By causing the hydraulic oil to flow out to the second line oil passage 52 through the second deceleration bypass oil passage 116, the effective diameter of the primary variable pulley 20 is rapidly reduced, and the effective diameter of the secondary variable pulley 22 is reduced. Increased.

The speed increasing bypass control valve 118 and the decelerating bypass control valve 120 are electromagnetic on-off valves that are controlled to either a fully open state or a fully open state, and are controlled by the controller 9.
4.

The belt-type continuously variable transmission 14 of the vehicle includes a primary rotating wheel 16.
A first rotation sensor 90 for detecting the rotation speed N i h of the secondary rotation shaft 18 and a second rotation sensor 92 for detecting the rotation speed N out of the secondary rotation shaft 18 are provided.
The first rotation sensor 90 and the second rotation sensor 92 output a rotation signal SRI representing the rotation speed N in and a rotation signal SR 2 representing the rotation speed N out to the controller 94 . The engine 10 of the vehicle also includes a throttle sensor 96 provided in its intake pipe for detecting a throttle valve opening θ, and a throttle sensor 96 for detecting the engine rotational speed N.

The throttle sensor 96 and the engine rotation sensor 98 send a throttle signal Sθ representing the throttle valve opening θ and a rotation signal SE representing the engine rotation speed N0 to the controller 94. Output to.

The controller 94 includes a CPU 102, a ROM 104
, a RAM 106, and the like. The CPU 102 processes input signals in accordance with a program stored in advance in the ROM104 while utilizing the memory function of the RAM 106, and operates the first pressure regulating valve 48 and A speed ratio signal for driving the first electromagnetic solenoid 74 and the second electromagnetic solenoid 76 to control the speed ratio e while supplying the first drive signal VDI and the second drive signal VD2 to the second pressure regulating valve 58, respectively. R.A.
Feed them with I and Rnor2. In addition, the controller 94 also includes a speed increasing bypass control valve 118 and a decelerating bypass control valve 1 in order to improve speed change responsiveness during transient times.
It outputs drive signals SBI and SB2 for operating 20.

The controller 94 includes speed change control, first line hydraulic control, second line hydraulic control, rapid speed change control? In is executed sequentially or selectively. In the speed change control, a target speed ratio e8 is calculated based on the vehicle's required output throttle valve opening O and the vehicle speed V from the relationship stored in advance in the ROM 104, and the target speed ratio e0 and the belt type stepless The speed change control valve 44 is adjusted so that the actual speed ratio e of the transmission 14 is a fraction of the actual speed ratio e. The relationship is determined in advance so that, for example, the engine 10 operates exclusively on the minimum fuel efficiency curve. Further, the above relationship may be used to determine the target rotational speed of the primary rotating shaft 16 for operating the engine 10 according to the minimum fuel consumption rate curve -F, for example. The first line hydraulic control and the second line hydraulic control are based on functions determined in advance to obtain the necessary and sufficient thrust of the primary hydraulic cylinder 26 and the secondary hydraulic cylinder 28, and calculate the actual speed ratio and output of the engine 10. The first line oil pressure Pβ1 and the second line oil pressure P2□ are determined based on the torque, the pressure receiving area and rotational speed of the primary side hydraulic cylinder 26 and the secondary side hydraulic cylinder 28, and the first line oil pressure P /l + and 2nd line oil pressure Pβ
The first pressure regulating valve 48 and the second pressure regulating valve 5
8 is activated.

The flowchart shown in FIG. 2 is a part of the above-mentioned speed change control, and shows a rapid speed change control routine provided for rapidly changing the speed ratio. In the figure, in step S1, the control value ■ for the speed change control valve 44 is set. is calculated using the following equation (1). In equation (1), in order to eliminate the deviation between the target speed ratio e1 and the actual speed ratio e, the control value V is set in proportion to the magnitude of the deviation (e''-e)/e.

is determined.

Vo = k (e' c) /I3...(
1) However, k is a constant.

In step S2, the magnitude of the deviation on the negative side is
')/e is predetermined judgment 1! , it is determined whether or not it is greater than or equal to the IT reference value C1, and in step S3, the magnitude of the deviation on the positive side e"-e)/c is greater than or equal to the predetermined judgment reference value C2 -1-. If the determinations in steps S2 and B3 are both negative, the speed ratio (!) of the belt-type continuously variable transmission 14 is determined.
Since there is no need to rapidly change the speed increase bypass control valve 118 in steps S4 and B5,
and the control value V for the deceleration bypass control valve 120
. I, and V. (11, is set to zero. That is, the speed-increasing bypass control'<if valve 118 and the decelerating bypass valve 120 are rendered inactive and maintained in a fully closed state.

However, for example, in step S2, the magnitude of the deviation on the negative side is set to a predetermined judgment reference value C1
If it is determined that the above is the case, the actual speed ratio e must be rapidly changed in the direction of decreasing it, and therefore, in step S6, the control value ■ for the speed increasing bypass control valve 118 is set. . , is set to zero, the control value ■ for the deceleration bypass control valve 120 is determined in step S7. . ) is assumed to be vc. This value ve is a value for outputting the driving power necessary to maintain the speed increasing bypass control valve 118 or the decelerating bypass control valve 120 in a fully open state. As a result, the first line oil rapidly passes through the deceleration bypass control generator 120 to the secondary hydraulic cylinder 28.
The hydraulic oil in the primary hydraulic cylinder 26 is rapidly discharged to the second line oil passage 52 through the deceleration bypass control valve 120.

Furthermore, if it is determined in step S3 that the magnitude of the deviation on the positive side (e''-e)/e is greater than or equal to the predetermined judgment reference value C2, the actual speed ratio e is increased. Since the condition must be changed rapidly, the speed increasing bypass control valve 118 is activated in step S8.
Control value for ■. (Al is set to vc, and in step S9, the control value ■ for the bypass control valve 120 for deceleration. The hydraulic oil supplied to the hydraulic cylinder 26 and within the secondary hydraulic cylinder 28 is rapidly flowed out to the second line oil passage 52 through the speed increasing bypass control valve 118 .

As described above, the above-mentioned judgment reference values CI and C2 are determined by the speed increasing bypass control valve 118 and the decelerating bypass control valve 1.
This is a value that determines when to start the operation of 20. If the value is too small, it will operate even when the speed ratio change speed is low, causing the speed ratio to overshoot and hunting to occur, so it is determined with this in mind. has been done. If the control flow rates of the speed-increasing bypass control valve 118 and the decelerating bypass control valve 120 are the same, normally C,<C. This is because the deceleration bypass control valve 120 needs to be opened with a smaller deviation than the deviation during the increase speed change, since a speed change is required more quickly during the deceleration change than during the increase speed change. .

As described above, according to this embodiment, the belt type continuously variable transmission 1
In the speed ratio control of No. 4, during a transient period in which the speed ratio is continuously changed, the hydraulic fluid is passed through the speed increasing bypass control valve 118 or the decelerating bypass control valve 120, so that the maximum flow rate of the speed change control valve 44, in other words, In this case, a sufficiently high speed change response can be obtained even if the maximum flow cross-sectional area is not so large.

Therefore, the speed change control valve 44 can be designed mainly to improve control accuracy during steady state, and does not require a large opening degree to improve speed change responsiveness during transient times. A high degree of control can be obtained in ratio control, and at the same time, high speed change responsiveness can be obtained.

Next, another embodiment of the present invention will be described. Note that in the following embodiments, parts common to those in the above-described embodiments are designated by the same reference numerals, and explanations thereof will be omitted.

As shown in FIG. 3, a second deceleration bypass oil passage 116 may be provided between the connection oil passage 29 and the drain oil passage 60.

In this case, when the hydraulic oil in the primary side hydraulic cylinder 26 is discharged during a rapid deceleration shift, it is discharged to atmospheric pressure lower than the second line hydraulic pressure P12, so that even higher shift responsiveness can be obtained, and Variable pulleys 20 and 2
There is an advantage that the transmission belt 24 can be easily moved in the deceleration direction when the transmission belt 24 is not rotating.

Further, as shown in FIG. 4, the speed increasing bypass control valve 118 and the decelerating bypass control valve 1 120 are operated by the drive signal SBI or SB2 supplied from the controller 94.
A linear control valve of the type in which the flow cross-sectional area is continuously changed according to the above-mentioned conditions may also be used. In this case, the shock that occurs when the speed increasing bypass control valve 118 and the decelerating bypass control valve 120 are activated can be alleviated.

Although the embodiments of the present invention have been described above in detail based on the drawings, the present invention can also be implemented in other embodiments.

For example, in the above-mentioned embodiment, the speed increasing bypass side f[I valve 1
18 and a deceleration bypass control valve 120 are used, but a single three-position solenoid valve having these functions may also be used.

Further, a certain effect can be obtained by removing either one of the speed-increasing bypass control valve 118 and the decelerating bypass control valve 120 of the above-described embodiment and closing the removed bypass oil passage. For example, the t17 bypass control valve 118 can be removed by slightly increasing the control flow rate of the speed change control valve 44 to ensure the maximum required flow rate during the speed increase. Normally, the maximum required flow rate for increasing speed is much smaller than that for decelerating, so this type of system is also fully practical.

Furthermore, instead of the speed increasing bypass control valve 118 and the decelerating bypass control valve 120, one linear valve having these functions may be used.

In this case, since it is preferably operated in proportion to the deviation in substantially the same way as the shift control valve 44, it is desirable to use an overlap valve with a dead zone in the neutral state in order to stabilize the control.

Further, in the embodiment shown in FIG. 3, the second speed increasing high bus oil passage 112 may be provided between the connection oil passage 30 and the drain oil passage 60.

Furthermore, although the embodiment described above is configured to make the speed ratio e and the target speed ratio e8 completely different, the rotational speed N in of the primary side rotating shaft 16 and its target rotational speed (target value) N,2
Exactly the same function and effect can be achieved even if the configuration is configured so as to cause one defeat.

Although other examples are not given, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a hydraulic control device for a vehicle belt-type continuously variable transmission, which is an embodiment of the present invention. FIG. 2 is a flowchart for explaining the operation of the embodiment shown in FIG. FIG. 3 is a diagram showing a hydraulic circuit according to another embodiment of the present invention. FIG. 4 is a diagram showing essential parts of a hydraulic circuit in another embodiment of the present invention. 14: Belt type continuously variable transmission 20 Primary variable pulley 22: Secondary variable pulley 24: Transmission belt 26 Primary hydraulic cylinder 28: Secondary hydraulic cylinder 44: Shift control valve 110: First speed increase Bypass oil passage 112: Second bypass oil passage 114 for speed increase: Bypass oil passage 116 for first deceleration: Bypass oil passage 118 for second deceleration: Bypass control valve for speed increase 120: Bypass control valve for deceleration

Claims (5)

[Claims] (1) A pair of primary variable pulleys and a secondary variable pulley provided on the primary rotating shaft and the secondary rotating shaft, respectively, and a transmission belt that is wound around the pair of variable pulleys to transmit power; In a vehicle belt-type continuously variable transmission comprising a pair of primary and secondary hydraulic cylinders that change the effective diameters of the pair of variable pulleys, first line oil at a predetermined pressure is applied to the primary hydraulic pressure. The effective diameter of the primary variable pulley and the secondary variable pulley is changed by supplying hydraulic oil to one of the cylinder and the secondary hydraulic cylinder while simultaneously causing the hydraulic oil in the other to flow out. A hydraulic control device of the type having a speed change control valve that adjusts a speed ratio of the speed change control valve, which is provided in parallel with the speed change control valve and supplies first line oil to one of the primary side hydraulic cylinder and the secondary side hydraulic cylinder. and a bypass oil passage for draining the hydraulic oil in the other, the bypass oil passage being provided with a first oil passage, the speed change control valve being connected to one of the primary hydraulic cylinder and the secondary oil cylinder.
A hydraulic control device for a belt-type continuously variable transmission for a vehicle, comprising: a bypass control valve that is opened when line oil is rapidly supplied and hydraulic oil in the other is rapidly drained. (2) The bypass oil passage includes a first speed increasing bypass oil passage for supplying first line oil to the primary hydraulic cylinder, and a first speed increasing bypass oil passage for draining the hydraulic oil in the secondary hydraulic cylinder. The hydraulic control device for a belt-type continuously variable transmission for a vehicle according to claim 1, which comprises two speed-increasing bypass oil passages. (3) The bypass oil passage includes a first deceleration bypass oil passage for supplying first line oil to the secondary hydraulic cylinder, and a second bypass oil passage for draining the hydraulic oil in the primary hydraulic cylinder. A hydraulic control device for a belt-type continuously variable transmission for a vehicle according to claim 1 or 2, which comprises a deceleration bypass oil passage. (4) The vehicle according to claim 2, wherein the bypass control valve is a speed increasing bypass control valve that simultaneously opens and closes the first speed increasing bypass oil path and the second speed increasing bypass oil path. Hydraulic control device for belt type continuously variable transmission. (5) The belt-type vehicle according to claim 3, wherein the bypass control valve is a deceleration bypass control valve that simultaneously opens and closes the first deceleration bypass oil passage and the second deceleration bypass oil passage. Hydraulic control device for continuously variable transmission.