JP2884959B2 - Hydraulic control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device, and more particularly, to a hydraulic pressure detecting structure for hydraulic control.

[0002]

2. Description of the Related Art As a structure used for a so-called continuously variable transmission, a belt is stretched between a pair of pulleys, and a groove width of the pulley on which the belt is hung is changed so that a drive side is connected to the pulley. There is a structure that changes the speed ratio obtained between the driven side and the driven side.

As one of the mechanisms for changing the groove width of the pulley, a movable conical plate facing one fixed conical plate constituting the pulley by using a hydraulic mechanism is used. There is a structure to displace in the axial direction.

[0004] An example of the above-mentioned hydraulic mechanism is disclosed in, for example, Japanese Patent Application Laid-Open No. 59-19755. In this structure, the oil from the oil pump set to a predetermined pressure by the pressure regulating valve is supplied to the hydraulic chamber side of the movable conical plate in the driven pulley, and the oil flow is extended from the pressure regulating valve to the oil passage. The pressure is set so as to obtain a transmission ratio at which the engine-side output torque can be transmitted through the control valve, and then the pressure is guided to the hydraulic chamber in the movable cone plate of the drive pulley.

[0005]

By the way, in the above-described transmission mechanism, when the groove width for obtaining the required speed ratio is set, the pressure of the hydraulic chamber on the driven pulley side is controlled by the pressure regulating valve. A regulated line pressure is provided, which must be adjusted to maintain the frictional engagement between the belt and the cone.

That is, when the engine is operated with a large torque, in other words, with a large throttle opening, the gear ratio is also increased. The groove width must be narrowed so that the pressing force against the belt can be increased.

On the other hand, when the engine is driven at a constant speed, the above-described engine side torque becomes small, so that an economical operating state can be set in consideration of fuel efficiency. In order not to cause excessive pressing force or to cause belt slippage on the contrary.
It is necessary to adjust the groove width on the pulley side.

Therefore, during constant speed operation, the adjustment of the groove width is more important than when the gear ratio is increased. For this reason, the operating pressure in the hydraulic control unit for adjusting the groove width on the driven pulley side is important. It is necessary to detect the line pressure corresponding to the above.

For this reason, conventionally, the hydraulic pressure in the hydraulic chamber on the driven pulley side has been tracked and detected by a hydraulic pressure sensor disposed at that position, and the groove width of the pulley on the drive side can be changed. Is output as pressure data for feedback control when the conical plate is displaced in conjunction with.

In addition to the above-described structure, there has been proposed a structure in which a hydraulic pressure sensor is provided in a hydraulic circuit for applying operating pressure to a forward clutch and a reverse brake (for example, Japanese Patent Application No. 3-39466). ).

A brief description of the latter structure will be given. An operation mode selection manual in which an oil passage for a forward clutch and a reverse brake in a forward / reverse switching mechanism is connected to switch the direction of applying hydraulic pressure to each part. An output circuit of a clutch pressure control valve is connected to the valve. In this clutch pressure control valve, the output hydraulic pressure is controlled by the duty control pressure of the solenoid valve with respect to the operating pressure set by the clutch pressure modulating valve. Is controlling.

A duty control circuit of the solenoid valve is connected to a clutch pressure control valve via a clutch control pressure switching valve, and the clutch control pressure switching valve is connected to a pressure set by a clutch pressure modulating valve. The circuit is switched according to the difference from the output pressure by the clutch pressure control valve. In other words, from the non-engaged state of the forward clutch and the reverse brake to the engaged state,
The duty of the solenoid valve is controlled to prevent the pressure from the clutch pressure control valve for the clutch from rising rapidly, so-called clutch engagement shock (N → D,
N → R shock).

In this hydraulic circuit, a hydraulic pressure sensor is arranged in an oil passage connecting the above-described clutch pressure control valve and the manual valve for operating mode selection.
For this reason, the clutch is in the operating state in the D range where the clutch is completely engaged, and the line pressure is introduced when the line pressure is lower than the maximum clutch pressure, and the valve is in communication with the valve. A line pressure is detected by a hydraulic pressure sensor via a clutch pressure control valve in which a displacement position of the spool is set, and a line pressure for setting a groove width of a driven pulley to which the line pressure is applied. Is performed.

However, in such a pressure detecting structure for setting the groove width, waste is likely to occur due to cost.
That is, in the case of the former structure, the hydraulic sensor attached to the hydraulic circuit is relatively expensive, and such an expensive sensor is used only for detecting the line pressure.

In the latter structure, although it is possible to detect the line pressure at the time of constant speed operation, the position of the oil pressure sensor for that purpose is determined by the clutch for setting the clutch operating pressure. Since it is located downstream of the pressure modulating valve, a line pressure set higher than the operating pressure set by this valve cannot be detected because the upper limit of the pressure is set. That is, only the line pressure equivalent to or less than the clutch operating pressure set by the clutch pressure modulating valve can be detected.

Accordingly, an object of the present invention is to use a hydraulic sensor only for detecting a line pressure for setting a groove width of a pulley in view of the above-mentioned conventional hydraulic mechanism, particularly in view of a problem with the hydraulic pressure detecting structure. In addition to reducing the cost for hydraulic pressure detection by eliminating the problem, it is possible to detect the line pressure over the entire range, so that feedback control on the servo pressure of the driven pulley can be performed under any conditions during traveling. It is another object of the present invention to obtain a hydraulic control device having a structure that can be performed in any of the above.

[0017]

In order to achieve this object, an invention according to claim 1 includes a forward / reverse switching device including a hydraulically operated friction element and a fluid coupling with a clutch, wherein the fluid coupling with a clutch is provided. By changing the pulley width of the drive pulley connected to the output side of the drive pulley and the driven pulley arranged in parallel with the drive pulley by hydraulic pressure, the winding diameter of the endless belt stretched between the two pulleys is changed. In a hydraulic control device for a continuously variable transmission that performs a stepped shift, a regulator valve for adjusting a discharge pressure from a hydraulic source, a hydraulic control valve for adjusting a hydraulic pressure supplied to the friction element, and an operating state of the clutch are controlled. A clutch control valve, a duty solenoid valve that generates a control oil pressure by being duty-driven, and a first position in which the duty solenoid valve communicates with the hydraulic control valve. First port Ido valve with switched between a second position communicating with the clutch control valve, regulating pressure from said regulator valve is introduced,
A second port and a third port through which the output pressure from the hydraulic control valve is introduced are formed, and the second port and the second port are formed at the first position.
A switching valve configured to communicate a port with the third port and configured to communicate the first port and the third port at the second position; and a hydraulic pressure detection unit coupled to the third port. It is characterized by having.

According to a second aspect of the present invention, there is provided a forward / reverse switching device comprising a hydraulically actuated friction element and a fluid coupling with a clutch, wherein the driving pulley is connected to the output side of the fluid coupling with the clutch. In a hydraulic control device for a continuously variable transmission that performs a continuously variable transmission by changing the pulley width with a driven pulley arranged in parallel by hydraulic pressure and changing the winding diameter of an endless belt stretched between both pulleys. A first and a second duty solenoid valves that generate control hydraulic pressure by being duty-operated, a regulator valve that communicates with the first duty solenoid valve and regulates a discharge pressure from a hydraulic pressure source, A hydraulic control valve for regulating a supply hydraulic pressure, a clutch control valve for controlling an operation state of the clutch, and a first position for communicating the second duty solenoid valve with the hydraulic control valve. The second duty valve is switched between a second position communicating with the clutch control valve, a first port through which the adjustment pressure from the regulator valve is introduced, and an output pressure from the hydraulic control valve. A second port and a third port are formed to communicate the second port and the third port at the first position, and to communicate the first port and the third port at the second position. A switching valve configured as described above, hydraulic pressure detecting means connected to the third port, and the second duty solenoid valve according to a detection value of the hydraulic pressure detecting means when the switching valve is at the first position. Feedback control, wherein when the switching valve is at the second position, feedback control of the first duty solenoid valve is performed in accordance with a detection value of the hydraulic pressure detection means. It is characterized in that a means.

[0019]

According to the present invention, when the clutch is engaged by the duty control of the solenoid valve via the clutch pressure control valve, the port for introducing the line pressure of the hydraulic sensor switching valve and the hydraulic pressure detection oil passage. The line pressure can be detected by the oil pressure sensor in the oil pressure detection oil passage by setting the position to communicate with.

Further, according to the present invention, when the position of the operation mode select manual valve is at "N" or "P" with respect to the above-mentioned oil pressure detection oil passage, or at "D" from this position. When the clutch is switched and the forward clutch or the reverse brake is engaged, the oil pressure sensor switching valve is set to a state in which the output pressure of the clutch pressure control valve communicates with the oil pressure detection oil passage, so that the clutch pressure control valve Field for duty control of clutch operating pressure by detecting output pressure
Debug control can be performed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a hydraulic circuit diagram for explaining the configuration of a hydraulic controller according to an embodiment of the present invention.

Before describing the circuit, a continuously variable transmission using the circuit will be described with reference to FIG.

That is, the continuously variable transmission used in this embodiment is attached to a fluid coupling 2 connected to the output shaft 1A of the engine 1.

And, this fluid coupling 2
It has a lock-up mechanism, and controls the oil pressure in the lock-up hydraulic chamber 2A to bring the pump impeller -2B on the input side and the turbine runner -2C on the output side into frictional engagement or apart from each other, thereby making the frictional engagement. The relationship is released.

The above-described fluid coupling 2 has an output shaft 2D provided on the output side thereof so as to be integrally rotatable.
The output shaft 2D is connected to the forward / reverse switching mechanism 3.

The forward / reverse switching mechanism 3 includes a planetary gear mechanism 4 having a well-known structure, a forward clutch 6 and a reverse brake 5, and the planetary gear is controlled by hydraulic control of the forward clutch 6 or the reverse brake 5. The rotation direction of the rotation shaft 4A connected to the output side of the mechanism 4 is switched.

On the other hand, a drive pulley 7 which is one of the main parts of the continuously variable transmission mechanism is provided on the rotary shaft 4A.

The drive pulley 7 is fixedly inserted into the fixed conical plate 7A at a position opposed to the fixed conical plate 7A and is axially movable at a position facing the fixed conical plate 7A. And a movable conical plate 7B.
A hydraulic chamber 7C is formed on the back side. The hydraulic chamber 7C is composed of first and second chambers 7C1 and 7C2, and the first chamber 7C1 and the second chamber 7C2 are
It is a pressing force generating section for displacing B.

The drive pulley 7 can be linked with a driven pulley 9 by a belt 8. The driven pulley 9 is driven to an output side when the drive pulley 7 is set to an input side of the rotational force. Position to,
A fixed cone plate 9A is inserted on the side of the drive pulley 7 opposite to the movable cone plate 7B, and a movable cone plate 9B is inserted into the boss portion of the fixed cone plate 9A so as to be movable in the axial direction. . In the driven pulley 9, a hydraulic chamber 9C is formed on the back surface of the movable conical plate 9B. By controlling the hydraulic pressure in the hydraulic chamber 9C, the groove width is changed in cooperation with the drive pulley 7 side. I can do it. The oil chamber 9 is located behind the hydraulic chamber 9C.
D is formed and acts as a centrifugal balance chamber.
That is, if the position of the movable conical plate 9B is displaced from a desired position by the axial component of the centrifugal force generated in the hydraulic chamber 9C, Suruga and the oil in the balance chamber 9D cancel the axial component force, so that the conical plate 9B is conical. The plate 9B is held at a desired position.

A driven shaft 10 is provided integrally with the fixed conical plate 9A of the driven pulley 9, and a driven gear 11 is attached to the driven shaft 10. This drive gear 11 is connected to the output shaft 1 via idle gears 12 and 13.
The rotation force from the drive pulley 7 side can be transmitted to the output shafts 14 and 15 by being connected to the final gear 16 of the differential gear mechanism 17 to which the transmission gears 4 and 15 are connected.

On the other hand, the hydraulic control structure for the drive pulley 7 and the driven pulley 9 in the hydraulic chambers 7C and 9C in the above-described continuously variable transmission mechanism is shown in FIG. Note that, in FIG. 1, the numbers shown in the circles indicate the hydraulic system.

FIG. 1 shows the mode of each valve when the position of the select lever provided in the driver's seat is set to a neutral state.

That is, in the hydraulic control structure of this embodiment, the line pressure, which will be described later, is directly applied to the hydraulic chamber 9C of the driven pulley 9.
It is a structure to be introduced. This structure is composed of an oil pump 18 and a regulator valve 1 for adjusting line pressure.
9, a duty control solenoid valve 20, a speed ratio control valve 21, and a control pressure modulating valve 22 for regulating the supply pressure to each solenoid valve. The oil passage from the control pressure modulating valve 22 serves as an oil supply system for duty control solenoid valves 20A, 20B, 20C for controlling line pressure, speed ratio, and clutch pressure.
A damper clutch control valve 2 for controlling the supply of hydraulic pressure to the damper clutch on the fluid coupling 2 side.
4 and a pilot pressure system to a clutch pressure control valve 25 for controlling the application state of the clutch pressure.

On the other hand, in the line pressure system, in addition to the hydraulic chamber of the driven pulley, a clutch pressure modulating valve 26 for setting the operating pressure of the clutch, a clutch control pressure switching valve 27 and the aforementioned damper clutch control valve There is an oil passage to 24.

The solenoid 20 described above has one of them.
20A applies a duty control pressure to the transmission ratio control valve 21 to supply oil to the hydraulic chamber of the drive pulley 7,
By controlling the amount of discharged oil, the groove width of the pulley is adjusted, that is, the speed ratio is controlled. The solenoid 20B controls the line pressure by applying a duty control pressure to the regulator valve 19 for adjusting the line pressure. When the feedback control for the duty control is performed, The reference pressure is taken into a control unit (TCU) 50 shown in FIG. 4 from a hydraulic pressure sensor in a hydraulic pressure detection oil passage described later.

At the discharge port of the clutch pressure control valve 25 described above, an oil passage to an operation mode selection manual valve 28 for switching the oil passage to the forward clutch 6 and the reverse brake 5 is provided. It is connected. The operation mode select manual valve 28 has a structure that can be linked to a select lever operated by the driver. This is because when the land portion of the spool is moved rightward from the neutral position (N) in the drawing, in other words, when it moves in the forward (D) direction, it moves from the clutch pressure control valve 25 toward the forward clutch 6. An oil supply oil passage is set, and the above-mentioned land portion is located on the left side of the illustrated neutral position, in other words,
Moving in the (R) direction, an oil supply oil path from the clutch pressure control valve 25 to the reverse brake 5 is set.

The oil path from the clutch pressure control valve 25 to the operation mode select manual valve 28 is a branched oil path 31 in the middle of the oil path. The oil path 31 is an output from the clutch pressure control valve 25. The pressure, in other words, the oil to which the pressure applied to the operation mode select manual valve 28 is set is applied to the clutch control pressure switching valve 2 described later.
7 is introduced.

Clutch control pressure switching valve 2
Reference numeral 7 denotes the direction of oil supply to the operation mode select manual valve 28 via the clutch pressure control valve 25 and the direction of oil supply to the damper clutch control valve 24 for controlling the operation of the damper clutch in the fluid coupling 2. And for switching the oil supply direction to the oil pressure detection circuit 31 described later. As shown in FIG. 3, the clutch control pressure switching valve 27 has a built-in spool 27A which is provided with a habit of moving rightward in the figure by a spring and is movable in the axial direction. The input pressure from the valve 26 normally moves the spool to the left in the drawing against the bias of the spring.

Clutch control pressure switching valve 2
7 has a solenoid valve 20C, a damper clutch control valve 2
4. An oil passage connected between the clutch pressure control valve 25 and the oil pressure detection oil passage 30 in which the oil pressure sensor 29 is disposed is connected. Further, in addition to these oil passages, an oil passage 31 branched from an oil passage from the clutch pressure control valve 25 to the operation mode select manual valve 28 and an oil passage branched from an oil passage to the forward clutch 6. 32, and an oil passage through which oil having a line pressure regulated by the regulator valve 19 can be introduced. In FIG. 3, for convenience, a portion of the clutch control pressure switching valve 27 where the oil passage through which the line pressure can be introduced (the position indicated by in FIG. 3) is a first port, and the oil passage 31 is connected. Where there is a second port, and
The location where the oil passage 30 is connected is referred to as a third port.

The clutch control pressure switching valve 27 is turned on when the built-in spool is in the first position in the above-described normal position, that is, in the illustrated operation mode.
When the manual valve 28 for deselect is in the neutral position, as shown above the center line in FIG. 3 among the oil passages described above by the lands provided on the spool,
An oil passage between the solenoid valve 20C and the clutch pressure control valve 25 and an oil passage 31 branched on the discharge side of the clutch pressure control valve 25 communicate with the oil pressure detection oil passage 30 through second and third ports. A posture for blocking other oil passages is set.

In this state, the duty control pressure is applied from the solenoid valve 20C to the clutch pressure control valve 25. Therefore, the operation mode selection manual valve 2
7 is displaced in the “D” direction from the neutral position, the pressure between the clutch pressure control valve 25 and the forward clutch 6 gradually increases through the pressure supplied from the solenoid valve 20C to the clutch pressure control valve 25. Ascending and clutch modulating valve 26
To reach the set pressure. The detection of the reference pressure for the duty control by the solenoid valve 20C at this time is detected by the hydraulic pressure sensor 29 by taking the output pressure from the clutch pressure control valve 25 into the hydraulic pressure detection oil passage 30 from the oil passage 31. It is taken into the unit 50. Therefore, when the operation mode selection manual valve 28 is operated from the neutral position to the “D” range, the pressure setting of the operating pressure of the forward clutch 6 is changed to the clutch pressure introduced into the hydraulic pressure detection oil passage 30. This is performed by detecting the output pressure from the control valve 25.

On the other hand, when the operating pressure to the forward clutch 6 is increased while the sudden increase in the pressure is suppressed by setting the operating pressure of the clutch through the duty control by the solenoid valve 20C, the spool moves to the position shown in FIG. It moves to the right and is displaced to the second position with respect to the first position described above. That is, the output pressure from the solenoid valve 20C via the clutch control pressure switching valve 27 is reduced, and the oil pressure is branched from the oil passage 32 branched from the oil passage to the forward clutch 6 into the clutch control pressure switching valve 27. The pressure of the oil introduced into the tank increases.

The position of the spool at this time is determined by the following equation. _{P 1A × A 1 = P 6} × A 2 + F S -kx However, P _1A: clutch pressure Mojure - pressure DOO valve, A _1:
Clutch pressure Mojure - sectional area of the surface receiving the pressure from the preparative valve 26, P _6: working pressure of the forward clutch 6, A _2: cross-sectional area of the surface receiving the forward clutch hydraulic pressure, F _S: spool in the Figure 3 - The spring force in the state shown in the lower half of the spool, k: the spring constant, and x: the displacement from the state shown in the lower half of the spool in FIG.

Accordingly, as the forward clutch 6 is engaged, an oil passage from the solenoid valve 20C to the damper clutch control valve 24 is connected to the clutch control pressure switching valve 27, and a line pressure introduction oil passage is provided. And the hydraulic pressure detection oil passage 30 begin to communicate through the first and third ports, and the other oil passages are shut off.

In this state, the damper clutch control valve 24
To the connection control of the damper clutch via the duty control from the solenoid valve 20C for the clutch control.
At this time, the line pressure is detected by the oil pressure sensor 29 via the oil pressure detection oil passage 30.

When the hydraulic pressure from the forward clutch 6 is sufficiently high and the forward clutch 6 is engaged, the output pressure from the clutch pressure control valve 25 and the oil pressure from the forward clutch 6 Since the output pressure from the oil passage 32 is set to an equilibrium state of the spool in the clutch control pressure switching valve 27, the communication state of the oil passage is maintained. Become.

Incidentally, the communication state between the line pressure introduction oil passage and the oil pressure detection oil passage 30 obtained when the equilibrium state of the spool in the clutch control pressure switching valve 27 is set is as follows. As described above, the state in which the line pressure is detected is set. Therefore, for example, as shown in FIG. 4, the line pressure is input to the control unit (TCU) 50. The pressure adjusted by the regulator valve 19 is directly input, and the duty ratio is changed according to the pressure. Is set.

That is, by detecting this line pressure,
The groove width of the pulley at the time of constant speed traveling, especially the pressure setting to the hydraulic chamber of the driven pulley directly operated by the line pressure, the hydraulic pressure indicating the same value as the pressure applied to this hydraulic chamber This makes it possible to optimize the oil pressure in the detection oil passage 30 based on the oil pressure.

Since the present embodiment has the above structure,
Oil from the oil pump 18 is supplied to the regulator valve 19.
Is set as a line pressure and supplied to each valve. The oil with the line pressure set is set to the operating pressure of the clutch by the clutch pressure modulating valve 26 and supplied to the clutch pressure control valve 25 and the clutch control pressure switching valve 27.

Clutch control pressure switching valve 2
At 7, the operation mode via the clutch pressure control valve 25 depends on the operating position of the operation mode selection manual valve 28.
The pressure applied to the manual valve 28
Control. And, by this control, the forward clutch 5
By the displacement of the spool according to the change of the working pressure on the side
The detection state of the reference pressure for the duty control and the detection state of the line pressure are switched and set.

Therefore, during the constant speed operation in which the forward clutch is engaged and the pressure in the spool in the clutch control pressure switching valve 27 is balanced, the spool in the clutch control pressure switching valve 27 is operated. Is switched from the setting of the oil passage to the clutch pressure control valve 25 to the setting of the oil passage to the damper clutch control valve 24.
For this reason, the line pressure can be detected at the same pressure as the value regulated by the regulator valve 19, and this detected value is used as the reference value of the duty control for setting the groove width of the pulley. Can be used as

[0053]

As described above, according to the present invention, the clutch for performing the duty control of the clutch operating pressure separately from the oil passage for applying the oil of the clutch operating pressure set by the clutch modulator valve. A structure is provided in which an oil passage that can directly detect line pressure in the control pressure switching valve can be set. As a result, the line pressure can be detected with the same value as the value regulated by the regulator valve. Accordingly, by using the hydraulic pressure sensor for controlling the clutch pressure in the clutch control pressure switching valve also for detecting the line pressure, the cost can be reduced because the hydraulic pressure sensor is not dedicated to the line pressure detection.

Further, according to the present invention, the oil pressure detection oil passage to the oil pressure sensor described above is connected to the clutch control pressure switching valve, and this oil pressure detection oil passage is connected to a sprue built in the switching valve. It can be used as a pressure detecting unit for duty-controlling the output pressure of the clutch pressure control valve until the clutch is engaged in accordance with the displacement of the clutch. Therefore, when the clutch is operated, the pressure rise can be adjusted by the duty control from the solenoid valve, so that the clutch engagement shock due to the sudden pressure rise can be suppressed. The detection of the reservoir pressure becomes possible.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram for explaining a hydraulic control mechanism according to an embodiment of the present invention.

FIG. 2 is a model diagram showing an example of a structure of a continuously variable transmission to which the hydraulic control mechanism shown in FIG. 1 is applied.

FIG. 3 is a model diagram for explaining a structure and operation of a main part in the hydraulic control mechanism shown in FIG. 1;

FIG. 4 is a block diagram for explaining a control unit used in the hydraulic control mechanism shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Fluid coupling 7 Driving pulley 8 Belt 9 Follower pulley 19 Regulator valve 20C Duty solenoid valve for clutch pressure control 25 Clutch pressure control valve 26 Clutch pressure modulating valve 27 Clutch control Pressure switching valve 28 Manual valve for operation mode selection 29 Oil pressure sensor 30 Oil pressure detection oil passage

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) E16H 59/00-61/12 E16H 61/16-61/24 E16H 63/40-63/48 B60K 41/00-41 / 28

Claims (2)

(57) [Claims] A drive pulley connected to an output side of the clutch-equipped fluid coupling, and a driven follower juxtaposed with the drive pulley having a forward-reverse switching device including a hydraulically operated friction element and a fluid coupling with a clutch. In a hydraulic control device of a continuously variable transmission that performs a continuously variable transmission by changing a pulley width between a pulley and a hydraulic pressure and changing a winding diameter of an endless belt stretched between the pulleys, a discharge from a hydraulic source A regulator valve that regulates pressure, a hydraulic control valve that regulates hydraulic pressure supplied to the friction element, a clutch control valve that controls the operating state of the clutch, and a duty solenoid valve that generates control hydraulic pressure by being duty driven. A first position at which the duty solenoid valve communicates with the hydraulic control valve and a second position at which the duty solenoid valve communicates with the clutch control valve. With Erareru, first adjusting pressure from the regulator valve is introduced 1
Port, the second of which the output pressure from the hydraulic control valve is introduced
A port and a third port are formed, the second port communicates with the third port at the first position, and the second port
A switching valve configured to communicate between the first port and the third port at a position; and a hydraulic pressure detecting means connected to the third port, the hydraulic pressure of the continuously variable transmission. Control device. 2. A drive pulley connected to the output side of a fluid coupling with a clutch, comprising: a forward / reverse switching device comprising a hydraulically actuated friction element and a fluid coupling with a clutch; The duty control is performed in the hydraulic control device of the continuously variable transmission that performs the continuously variable transmission by changing the pulley width between the pulley and the hydraulic pressure and changing the winding diameter of the endless belt stretched between the two pulleys. First and second duty solenoid valves that generate control oil pressure according to the first and second duty solenoid valves; a regulator valve that is connected to the first duty solenoid valve and adjusts a discharge pressure from a hydraulic source; A control valve, a clutch control valve for controlling an operation state of the clutch, a first position for communicating the second duty solenoid valve with the hydraulic control valve, and the second duty. Is switched between a second position communicating with the clutch control valve, and a first port through which an adjustment pressure from the regulator valve is introduced and a second port through which an output pressure from the hydraulic control valve is introduced. And a third port are formed, and the second and third ports communicate with each other at the first position.
A switching valve configured to communicate the first port with the third port at a position, a hydraulic pressure detecting means connected to the third port, and a hydraulic pressure when the switching valve is at the first position. Feedback control of the second duty solenoid valve is performed in accordance with a detection value of the detection means, and feedback control of the first duty solenoid valve is performed in accordance with a detection value of the hydraulic pressure detection means when the switching valve is in the second position. A hydraulic control device for a continuously variable transmission, comprising: control means.