JP4016866B2 - Hydraulic control device for transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, in the configuration for controlling the gear ratio of the belt type continuously variable transmission, the present invention relates to a hydraulic control device for varying the speed.
[0002]
[Prior art]
In a hydraulically controlled transmission, a technique is known in which the transmission ratio of the transmission is controlled by controlling the amount of oil supplied to the hydraulic chamber. An example of such a hydraulically controlled transmission is described in Japanese Patent Laid-Open No. 2001-12590 (Patent Document 1). The transmission described in this publication is a belt-type continuously variable transmission, and the belt-type continuously variable transmission includes a primary pulley and a secondary pulley, and a belt wound around the primary pulley and the secondary pulley. ing. A hydraulic actuator is disposed corresponding to the primary pulley, and the hydraulic actuator has a hydraulic chamber.
[0003]
In addition, a primary regulator valve, a secondary regulator valve, and a ratio control valve are provided in the hydraulic circuit of the transmission, and the line pressure is regulated by the primary regulator valve, and the secondary pressure is regulated by the secondary regulator valve. Then, the ratio control valve is controlled by the signal pressure from the linear solenoid valve for the ratio control valve, and the hydraulic pressure from the output port of the ratio control valve is supplied to the hydraulic chamber of the hydraulic actuator of the primary pulley to change the CVT speed. The ratio is controlled.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-12590 (paragraph numbers 0020 to 0033, FIGS. 1 and 3)
[0005]
[Problems to be solved by the invention]
However, in the hydraulic control device described in the above publication, the hydraulic chamber is supplied to the hydraulic chamber due to the correspondence between the hydraulic chamber of the hydraulic actuator of the primary pulley and the hydraulic pressure of the oil passage communicating with the hydraulic chamber. The amount of oil to be discharged or the amount of oil discharged from the hydraulic chamber may not be the amount of oil corresponding to the signal pressure of the solenoid valve for the ratio control valve. As a result, the controllability of the oil amount supplied to the hydraulic chamber or the controllability of the oil amount discharged from the hydraulic chamber may be reduced.
[0006]
The present invention has been made against the background described above, and an object of the present invention is to provide a hydraulic control device for a transmission that can suppress a decrease in the controllability of the oil amount in the hydraulic chamber.
[0007]
[Means for Solving the Problem and Action]
In order to achieve the above object, the invention of claim 1 is directed to a belt type continuously variable transmission in which a belt is wound around a primary pulley and a secondary pulley, and oil is supplied and discharged to the belt type continuously variable transmission. Controls the hydraulic chamber that controls the gear ratio, the amount of oil supplied from the input port to the hydraulic chamber via the output port, and the amount of oil discharged from the hydraulic chamber to the drain port via the output port and a flow control valve, the hydraulic control device for varying the speed, the flow control valve, when the valve body is operated in the positive direction, the amount of oil supplied to the hydraulic chamber via said output port When the amount of oil that increases and the oil discharged from the hydraulic chamber to the drain port decreases, the oil supplied from the output port to the hydraulic chamber when the valve body operates in the reverse direction. An oil amount control mechanism configured to output a signal pressure that operates in the forward and reverse directions, and is configured to increase the amount of oil discharged from the hydraulic chamber to the drain port. An oil passage connecting the output port and the hydraulic chamber, and an orifice disposed in the oil passage, and a hydraulic pressure between the orifice and the output port in the oil passage is greater than the oil pressure. When the hydraulic pressure between the hydraulic chamber and the orifice in the passage is higher than that, the hydraulic pressure between the orifice and the output port in the oil passage is transmitted to the valve body, and the valve body is urged in the reverse direction. If the hydraulic pressure between the first feedback port that generates the urging force and the hydraulic chamber and the orifice in the oil passage is higher than the hydraulic pressure between the orifice and the output port in the oil passage, A biasing force control mechanism having a second feedback port that transmits a hydraulic pressure between the hydraulic chamber and the orifice in the oil passage to the valve body and generates a biasing force that biases the valve body in the positive direction; it is shall be a feature of which is provided.
[0008]
According to the first aspect of the present invention , the flow control valve increases the amount of oil supplied to the hydraulic chamber via the output port when the valve element operates in the forward direction, and the drain port from the hydraulic chamber. The amount of oil discharged is reduced. On the other hand, when the valve element operates in the reverse direction, the amount of oil supplied from the output port to the hydraulic chamber decreases, and the amount of oil discharged from the hydraulic chamber to the drain port increases. The amount of oil supplied to the hydraulic chamber and the amount of oil discharged from the hydraulic chamber to the drain port are controlled to control the gear ratio of the belt type continuously variable transmission. Further, when the hydraulic pressure between the output port and the orifice in the oil passage is higher than the hydraulic pressure between the orifice and the hydraulic chamber in the oil passage, the valve body is operated in the reverse direction. In contrast, when the hydraulic pressure between the orifice in the oil passage and the hydraulic chamber is higher than the hydraulic pressure between the output port in the oil passage, the valve body is operated in the forward direction.
[0009]
A second aspect of the present invention, in addition to the first aspect, before Symbol belt-type continuously variable transmission, and a configuration in which the hydraulic chamber the speed ratio amount of oil is supplied is reduced to the speed change is executed, a shall be and characterized in that it has a structure and said speed change gear ratio increases the oil is discharged from the hydraulic chamber is executed.
[0010]
According to the invention of claim 2, in addition to the effect similar to that of the invention of claim 1, the amount of oil is supplied to the hydraulic chamber and the gear ratio of the belt type continuously variable transmission is reduced. Is discharged, and the gear ratio of the belt-type continuously variable transmission is increased.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described based on specific examples. FIG. 1 is a conceptual diagram when a belt-type continuously variable transmission 2 for a vehicle is controlled by a hydraulic control device 1 of the present invention. The belt type continuously variable transmission 2 includes a primary pulley 3 and a secondary pulley 4, and a belt 5 is wound around the primary pulley 3 and the secondary pulley 4. A driving force source (not shown) is connected to the primary pulley 3 so that power can be transmitted, and a wheel (not shown) is connected to the secondary pulley 4 so that power can be transmitted. Further, the primary pulley 3 has a movable sheave that can operate in the axial direction and a fixed sheave that does not operate in the axial direction. A first hydraulic chamber 6 that controls the groove width of the primary pulley 3 is provided. Moreover, the secondary pulley 4 has a movable sheave that can operate in the axial direction and a fixed sheave that does not operate in the axial direction. Further, a second hydraulic chamber 7 for controlling the groove width of the secondary pulley 4 is provided.
[0014]
In the above configuration, when the torque of the driving force source is transmitted to the primary pulley 3, the torque of the primary pulley 3 is transmitted to the secondary pulley 4 via the belt 5, and the torque of the secondary pulley 4 is transmitted to the wheels for driving. Force is generated. Further, the groove width of the primary pulley 3 is controlled based on the amount of oil in the first hydraulic chamber 6, and the winding diameter of the belt 5 in the primary pulley 3 is changed to change the speed of the belt type continuously variable transmission 2. The ratio is controlled. Further, the clamping pressure applied from the secondary pulley 4 to the belt 5 changes based on the hydraulic pressure in the second hydraulic chamber 7, and the torque capacity transmitted by the belt type continuously variable transmission 2 is controlled.
[0015]
The hydraulic control device 1 has a function of controlling the amount of oil supplied to the first hydraulic chamber 6 and the hydraulic pressure transmitted to the second hydraulic chamber 7. Hereinafter, the configuration of the hydraulic control device 1 will be described. The hydraulic control device 1 has an oil passage 8 that is connected to a discharge port of an oil pump (not shown). A configuration in which the oil pump is driven by a driving force source such as an engine or an electric motor can be employed. The oil passage 8 and the second hydraulic chamber 7 are connected by an oil passage 9. Further, an oil passage 10 connected to the first hydraulic chamber 6 is formed, and a ratio control valve 11 is provided at a connection portion between the oil passage 10 and the oil passage 8.
[0016]
The ratio control valve 11 includes a spool 12 operable in the vertical direction in FIG. 1 and elastic members 13 and 14 for applying a biasing force to the spool 12. One elastic member 13 generates a biasing force F1 that biases the spool 12 downward, and the other elastic member 14 generates a biasing force F2 that biases the spool 12 upward. That is, the direction of the urging force F1 is opposite to the direction of the urging force F2. In addition, when using a spring as the elastic members 13 and 14, the spring constant is set identically.
[0017]
Further, the ratio control valve 11 has a first signal pressure port 15 and a second signal pressure port 16. Then, the signal pressure of the first linear solenoid valve 17 is input to the first signal pressure port 15. The first linear solenoid valve 17 is a so-called normally closed type valve that is configured so that the output signal pressure is the lowest when the current value to the electromagnetic coil is controlled to the lowest value. is there. A biasing force F1 that biases the spool 12 downward is generated by the signal pressure input to the first port 15.
[0018]
On the other hand, the signal pressure of the second linear solenoid valve 18 is input to the second signal pressure port 16. The second linear solenoid valve 18 is a so-called normally closed type valve that is configured so that the output signal pressure becomes the lowest when the current value to the electromagnetic coil is controlled to the lowest value. is there. A biasing force F <b> 2 that biases the spool 12 upward is generated by the signal pressure input to the second signal pressure port 16.
[0019]
Further, the ratio control valve 11 has a first feedback port 19 and a second feedback port 20, and the ratio control valve 11 has an input port 21, an output port 22 and a drain port 23. . The oil passage 8 and the input port 21 are connected, and the output port 22 and the oil passage 10 are connected. Further, an oil pan communicates with the drain port 23.
[0020]
An orifice 24 is provided in the oil passage 10, and an oil passage 25 is formed in the oil passage 10 to connect a portion between the output port 22 and the orifice 24 and the first feedback port 19. Has been. In accordance with the hydraulic pressure of the first feedback port 19, an urging force F1 that urges the spool 12 downward is generated. In addition, an oil passage 26 that connects the second feedback port 20 and a portion between the first hydraulic chamber 6 and the orifice 24 is formed in the oil passage 10. A biasing force F <b> 2 that biases the spool 12 upward is generated according to the hydraulic pressure of the second feedback port 20.
[0021]
The function of the hydraulic control apparatus 1 having the above configuration will be described. First, oil in an oil pan (not shown) is sucked by the oil pump, and the oil discharged from the oil pump is supplied to the oil passage 8. The oil pressure (line pressure) PL in the oil passage 8 is regulated by a pressure regulating valve. Part of the oil in the oil passage 8 is supplied to the oil passage 9, and the hydraulic pressure is regulated by a pressure regulating valve (not shown), and the hydraulic pressure is transmitted to the second hydraulic chamber 7. In this way, the torque capacity of the belt type continuously variable transmission 2 is controlled. The torque capacity of the belt type continuously variable transmission 2 is controlled by the hydraulic pressure of the second hydraulic chamber 7, but the hydraulic pressure of the second hydraulic chamber 7 changes depending on the oil, so the second hydraulic chamber 7 It can be said that the amount of oil supplied to the engine is also related to the torque capacity.
[0022]
On the other hand, the shift control of the belt type continuously variable transmission 2 is performed by the ratio control valve 12. First, when executing deceleration control, that is, shift control that increases the gear ratio of the belt-type continuously variable transmission 2, the signal pressure input to the first signal pressure port 15 is changed to the second signal pressure. Set higher than the signal pressure input to the port 16. Then, the spool 12 operates downward in FIG. 1, the communication area between the input port 21 and the output port 22 decreases, and the communication area between the output port 22 and the drain port 23 increases. As a result, the oil in the first hydraulic chamber 6 is drained, the groove width of the primary pulley 3 is increased, the winding radius of the belt 5 in the primary pulley 3 is reduced, and the gear ratio of the belt type continuously variable transmission 2 is increased. An increasing shift is executed.
[0023]
Next, in the case of executing the speed increasing control, that is, the speed change control in which the speed ratio of the belt type continuously variable transmission 2 is reduced, the signal pressure input to the second signal pressure port 16 is It is set higher than the signal pressure input to the signal pressure port 15. Then, the spool 12 operates upward in FIG. 1, the communication area between the input port 21 and the output port 22 increases, and the communication area between the output port 22 and the drain port 23 decreases. As a result, the amount of oil supplied from the oil passage 8 to the first hydraulic chamber 6 increases, the groove width of the primary pulley 3 is narrowed, the winding radius of the belt 5 in the primary pulley 3 is increased, and the belt type Shifting is performed so that the gear ratio of the continuously variable transmission 2 is reduced.
[0024]
Further, when the transmission ratio is controlled to be substantially constant, the signal pressure input to the first signal pressure port 15 and the signal pressure input to the second signal pressure port 16 are controlled to be the same. For example, when control is performed so that no current is supplied to both the first linear solenoid valve 17 and the second linear solenoid valve 18, the signal pressure input to the first signal pressure port 15 and the second signal The signal pressure input to the pressure port 16 is the same, specifically, the lowest pressure.
[0025]
In this way, when the signal pressure input to the first signal pressure port 15 and the signal pressure input to the second signal pressure port 16 are controlled to be the same, the urging force generated by the elastic member 13 F1 and the urging force F2 generated by the elastic member 14 are canceled out, and the spool 12 stops at a predetermined neutral position. Then, the ports 21, 22, 23 are all shut off, the oil in the oil passage 8 is not supplied to the first hydraulic chamber 6, and the oil in the first hydraulic chamber 6 is not drained from the drain port 23. . Accordingly, the amount of oil in the first hydraulic chamber 6 is controlled to be substantially constant, and the gear ratio of the belt type continuously variable transmission 2 is fixed. Control for controlling the amount of oil in the first hydraulic chamber 6 to be substantially constant is referred to as “binding control”.
[0026]
Thus, the amount of oil in the first hydraulic chamber 6, specifically, the amount of oil supplied to the first hydraulic chamber 6 and the amount of oil discharged from the first hydraulic chamber 6 are basically It is controlled based on the signal pressure output from the first linear solenoid valve 17 and the second linear solenoid valve 18. By the way, depending on the oil pressure of the oil passage 8 and the oil pressure of the first hydraulic chamber 6, there is a possibility that the amount of oil in the first hydraulic chamber 6 cannot be appropriately controlled by the above signal pressure.
[0027]
For example, when the acceleration control is executed, if the hydraulic pressure in the first hydraulic chamber 6 is greater than or equal to a predetermined value, the oil in the first hydraulic chamber 6 is irrespective of the communication area between the input port 21 and the output port 22. The amount is less likely to increase. As a result, the acceleration speed may decrease. On the other hand, when the deceleration control is executed, if the hydraulic pressure in the first hydraulic chamber 6 is greater than or equal to a predetermined value, the amount of oil in the first hydraulic chamber 6 regardless of the communication area between the output port 22 and the drain port 23. Decreases rapidly. As a result, the deceleration speed may increase rapidly.
[0028]
On the other hand, even when the gear ratio of the belt-type continuously variable transmission 2 is fixed, there is a predetermined amount of oil leakage from the seal portion of the first hydraulic chamber 6, and in order to keep the gear ratio constant, Similarly, it is possible to supply the oil from the oil passage 8 to the first hydraulic chamber 6 and execute control to substantially match the oil leakage amount and the oil supply amount. However, in this case as well, for the same reason as in the speed increase control, it is difficult to supply oil to the first hydraulic chamber 6, and the gear ratio may change.
[0029]
On the other hand, according to the hydraulic control device 1 of FIG. 1, such a problem can be solved. First, at the time of deceleration control of the belt type continuously variable transmission 2, the oil in the first hydraulic chamber 6 is drained to the oil pan. Here, if the hydraulic pressure Pin2 of the oil passage between the orifice 24 and the first hydraulic chamber 6 is higher than the hydraulic pressure Pin1 of the oil passage between the output port 22 and the orifice 24, the first hydraulic chamber. The amount of oil discharged from 6 tends to increase. When the hydraulic pressure Pin2 transmitted to the second feedback port 20 is higher than the hydraulic pressure Pin1 transmitted to the first feedback port 19, the spool 12 is urged upward in FIG. It can suppress that the oil quantity of the hydraulic chamber 6 reduces rapidly.
[0030]
Further, during deceleration control of the belt type continuously variable transmission 2, the oil pressure Pin2 of the oil passage between the orifice 24 and the first hydraulic chamber 6 is set to be greater than the oil pressure Pin1 of the oil passage between the output port 22 and the orifice 24. If it is lower, the amount of oil discharged from the first hydraulic chamber 6 tends to decrease. When the hydraulic pressure Pin2 transmitted to the second feedback port 20 is lower than the hydraulic pressure Pin1 transmitted to the first feedback port 19, the spool 12 is urged downward in FIG. An increase in the amount of oil discharged from the hydraulic chamber 6 can be promoted.
[0031]
On the other hand, at the time of speed increase control of the belt-type continuously variable transmission 2, the oil pressure Pin1 of the oil passage between the output port 22 and the orifice 24 is greater than that of the oil passage between the orifice 24 and the first hydraulic chamber 6. If it is higher than the hydraulic pressure Pin2, the amount of oil supplied to the first hydraulic chamber 6 tends to increase. When the hydraulic pressure Pin1 transmitted to the first feedback port 19 is higher than the hydraulic pressure Pin2 transmitted to the second feedback port 20, the spool 12 is urged downward in FIG. An abrupt increase in the amount of oil in the hydraulic chamber 6 can be suppressed.
[0032]
Further, during the speed increase control of the belt type continuously variable transmission 2, the oil pressure in the oil passage between the orifice 24 and the first hydraulic chamber 6 is higher than the oil pressure Pin1 in the oil passage between the output port 22 and the orifice 24. If Pin2 is higher, the amount of oil supplied to the first hydraulic chamber 6 tends to decrease. When the hydraulic pressure Pin2 transmitted to the second feedback port 20 is higher than the hydraulic pressure Pin1 transmitted to the first feedback port 19, the spool 12 is urged upward in FIG. An increase in the amount of oil supplied to the hydraulic chamber 6 can be promoted.
[0033]
Thus, the amount of oil supplied to the first hydraulic chamber 6 and the amount of oil discharged from the first hydraulic chamber 6 are the signal pressure Psol 1 and the second pressure output from the first linear solenoid valve 17. In addition to the signal pressure Psol 2 output from the linear solenoid valve 18, the hydraulic pressure transmitted to the first feedback port 19 and the second feedback port 20 varies. Therefore, at the time of deceleration control, the value obtained by subtracting the hydraulic pressure Pin1 from the hydraulic pressure Pin2 becomes a desired value (a value such that the amount of oil discharged from the first hydraulic chamber 6 becomes a desired amount). By controlling the correspondence between the signal pressure Psol 1 of the first linear solenoid valve 17 and the signal pressure Psol 2 of the second linear solenoid valve 17, the deceleration speed during deceleration control is set to an arbitrary value. And drivability is improved.
[0034]
Further, at the time of speed increase control, the value obtained by subtracting the hydraulic pressure Pin2 from the hydraulic pressure Pin1 becomes a desired value (a value such that the amount of oil supplied to the first hydraulic chamber 6 becomes a desired amount). By controlling the correspondence between the signal pressure Psol 1 of the first linear solenoid valve 17 and the signal pressure Psol 2 of the second linear solenoid valve 17, the acceleration speed during the acceleration control can be set to an arbitrary value. It can be set and drivability is improved.
[0035]
Further, when the speed ratio of the belt type continuously variable transmission 2 is fixed, the amount of oil leaking from the first hydraulic chamber 6 and the first hydraulic chamber 6 are supplied for the same reason as in the acceleration control. The amount of oil to be obtained can be made substantially coincident. Accordingly, waste of oil consumption due to the movable sheave of the primary pulley 3 being unnecessarily stroked can be reduced. When the oil pump is driven by the power of the engine, it is possible to suppress a reduction in fuel consumption due to waste of the oil discharge amount of the oil pump. Thus, in this embodiment, the amount of oil supplied to the first hydraulic chamber 6 without being affected by the hydraulic pressure of the first hydraulic chamber 6 or the hydraulic pressure PL of the oil passage 8, and the first The amount of oil discharged from the hydraulic chamber 6 can be controlled, and the shift controllability of the belt type continuously variable transmission 2 is improved.
[0036]
In the embodiment of FIG. 1, the amount of oil supplied to the first hydraulic chamber 6 that controls the gear ratio of the belt type continuously variable transmission 2 or the amount of oil discharged from the first hydraulic chamber 6 is controlled. In the case of controlling, the amount of oil supplied to the second hydraulic chamber 7 for controlling the torque capacity of the belt-type continuously variable transmission 2 or the amount of oil discharged from the second hydraulic chamber 7 is controlled. It is also possible to apply this embodiment.
[0037]
Configuration of this embodiment, will be described the correspondence between the configuration of the present invention, the first hydraulic chamber 6 is equivalent to the hydraulic pressure chamber of the invention, Le Zion control valve 11, flow control valve of the present invention corresponds to the oil passage 10 corresponds to "an oil passage that connects the output port and the hydraulic chamber" of the present invention, hydraulic Pin2 is, "oil pressure between the hydraulic chamber and the orifice in the oil passage" of the present invention corresponds to, hydraulic Pin1 is equivalent to "oil pressure between the output port and the orifice in the oil passage" of the present invention, the first feedback oil channel 25, the second feedback oil passage 26, a first feedback in The port 19 and the second feedback port 20 correspond to the urging force applying mechanism of the present invention , and the first linear solenoid valve 17 and the second linear solenoid valve 18 correspond to the oil amount control mechanism of the present invention. Spool 12 corresponds to the valve element of the present invention, "when the spool 12 is operated upward in FIG. 1" is equivalent to "when the valve body is operated in the positive direction" of the present invention, "the spool 12 The case “operating downward in FIG. 1” corresponds to “the case where the valve element operates in the reverse direction” of the present invention.
[0038]
【The invention's effect】
As described above, according to the first aspect of the present invention, based on the correspondence between the hydraulic pressure between the hydraulic chamber and the orifice and the hydraulic pressure between the orifice and the output port , the flow control valve is changed to the hydraulic chamber. At least one of the amount of oil supplied or the amount of oil discharged from the hydraulic chamber via the flow control valve can be controlled appropriately, and the shift speed of the belt-type continuously variable transmission can be set to an arbitrary value. It can be set, as possible out to improve the control accuracy of the gear ratio.
[0039]
According to the invention of claim 1, when the valve element operates in the forward direction, the amount of oil supplied to the hydraulic chamber increases and the amount of oil discharged from the hydraulic chamber decreases. On the other hand, when the valve body operates in the reverse direction, the amount of oil supplied to the hydraulic chamber decreases and the amount of oil discharged from the hydraulic chamber increases.
[0040]
According to the second aspect of the invention, the same effect as that of the first aspect of the invention can be obtained. In addition, the oil amount is supplied to the hydraulic chamber and the gear ratio of the belt-type continuously variable transmission is reduced. Oil is discharged from the chamber, and the gear ratio of the belt type continuously variable transmission increases.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Hydraulic control apparatus, 2 ... Belt-type continuously variable transmission, 3 ... Primary pulley, 6, 7 ... Hydraulic chamber, 10 ... Oil passage, 11 ... Ratio control valve, 12 ... Spool, 19 ... 1st feedback port, DESCRIPTION OF SYMBOLS 20 ... 2nd feedback port, 24 ... Orifice, 25 ... 1st feedback oil path, 26 ... 2nd feedback oil path, F1, F2 ... Energizing force, Pin1, Pin2 ... Hydraulic pressure.

Claims (2)

A belt-type continuously variable transmission in which a belt is wound around a primary pulley and a secondary pulley, a hydraulic chamber that controls the speed ratio of the belt-type continuously variable transmission by supplying and discharging oil, and an input port through an output port the amount of oil supplied to the hydraulic chamber and, and having a flow control valve for controlling the oil amount discharged to the drain port through the output port from the hydraulic chamber, the hydraulic control device for varying the speed,
The flow control valve increases the amount of oil supplied to the hydraulic chamber via the output port when the valve element operates in the forward direction, and is discharged from the hydraulic chamber to the drain port. When the amount of oil decreases while the valve body operates in the reverse direction, the amount of oil supplied from the output port to the hydraulic chamber decreases, and the oil discharged from the hydraulic chamber to the drain port Configured to increase the amount,
An oil amount control mechanism that outputs a signal pressure that operates the valve body in the forward and reverse directions, an oil passage that connects the output port and the hydraulic chamber, and an orifice disposed in the oil passage are provided. ,
If the oil pressure between the orifice and the output port in the oil passage is higher than the oil pressure between the oil pressure chamber and the orifice in the oil passage, the oil pressure between the orifice and the output port in the oil passage Is transmitted to the valve body and the hydraulic pressure between the hydraulic chamber and the orifice in the oil path is higher than the first feedback port that generates a biasing force that biases the valve body in the reverse direction. When the hydraulic pressure between the orifice and the output port in the oil passage is higher than that, the hydraulic pressure between the hydraulic chamber and the orifice in the oil passage is transmitted to the valve body, and the valve body is urged in the positive direction. A hydraulic control apparatus for a transmission, characterized in that an urging force control mechanism having a second feedback port for generating an urging force is provided . Before Symbol belt type continuously variable transmission, the configuration and said hydraulic chamber the speed ratio amount of oil is supplied is reduced to the speed change is executed, the transmission ratio becomes larger gear shifting oil is discharged from the hydraulic chamber There hydraulic control device for a transmission according to claim 1, characterized in that it has a structure as to be executed.

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