JP2014202335A - Hydraulic control device of transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the controllability of a hydraulic control device, which uses a balance piston type valve, according to oil temperature.SOLUTION: In a hydraulic control device of a transmission, in which at least one of a supply valve and a discharge valve is formed of a balance piston type valve, a control solenoid valve in the balance piston type valve is configured to vary in the opening according to a controlled variable. A throttle part, which is formed by opening of the control solenoid valve, is so configured that the increment of flow resistance associated with increase in the viscosity of hydraulic pressure becomes larger than the increment of flow resistance at a control orifice in the balance piston type valve. The hydraulic control device is equipped with control variable set means (step S3) which, when the temperature of the hydraulic pressure is low, increases the opening of the control solenoid valve as compared with that when the temperature of the hydraulic pressure is high.

Description

  The present invention relates to a hydraulic control device for a transmission in which a gear ratio, a transmission torque capacity, and the like are controlled by hydraulic pressure, and more particularly, hydraulic pressure configured to control supply and discharge of hydraulic pressure by a balanced piston type solenoid valve. The present invention relates to a control device.

  The transmission ratio by the transmission is switched by changing the torque transmission path and the torque transmission point, and in a transmission in which a friction engagement element is disposed in the torque transmission path, the transmission force of the transmission is The transmission torque capacity as a whole is determined. 2. Description of the Related Art Conventionally, there is known a transmission configured to perform such a gear ratio switching and transmission torque capacity setting by hydraulic pressure, and an example thereof is described in Patent Document 1.

  The transmission described in Patent Document 1 is a belt-type continuously variable transmission, and each of a driving pulley (primary pulley) and a driven pulley (secondary pulley) around which the belt is wound is a fixed sheave and its fixed The movable sheave is configured to change the width of the belt winding groove by approaching or separating from the sheave. A supply valve for supplying the hydraulic pressure of the hydraulic source and a discharge valve for discharging the hydraulic pressure to the drain location are connected to each hydraulic chamber that imparts thrust to the movable sheave. Then, by opening the supply valve connected to one pulley (for example, the primary pulley) and supplying hydraulic pressure, the groove width of the primary pulley is narrowed and the belt winding radius is increased, resulting in an upshift. On the other hand, by opening the discharge valve and discharging the hydraulic pressure from the primary pulley, the groove width is widened, the belt winding radius is reduced, and a downshift is caused. On the other hand, if the supply valve connected to the other pulley (for example, the secondary pulley) is opened and the hydraulic pressure is supplied to the secondary pulley, the clamping pressure for clamping the belt increases and the transmission torque capacity increases. By opening the discharge valve and discharging the hydraulic pressure from the secondary pulley, the clamping pressure for clamping the belt is reduced, and the transmission torque capacity is reduced.

  Further, Patent Document 1 describes a balanced piston type solenoid valve that can be used as the above-described supply valve or discharge valve. This solenoid valve is housed so that a piston integrated with a needle-like or shaft-like valve body can be moved back and forth in the axial direction inside the cylinder part, and in the oil chamber in which the valve body is housed. An inflow port communicated with the high pressure portion and an outflow port communicated with the low pressure portion are formed, and the valve body is closed by being abutted against a valve seat that is an open end of the outflow port on the oil chamber side. It is comprised so that it may be in a state. In addition, the oil chamber and the oil chamber on the opposite side of the oil chamber with a piston interposed therebetween (hereinafter referred to as a control oil chamber) are communicated with each other via a communication passage having a control orifice. Further, the control oil chamber communicates with the low pressure portion, and a control solenoid for opening and closing the control oil chamber with respect to the low pressure portion is provided. Therefore, by opening the control solenoid, the hydraulic pressure in the control oil chamber decreases, and as a result, the piston moves backward to the control oil chamber side, the valve body is separated from the valve seat, and the control solenoid is opened. By performing the closing control, the hydraulic pressure of the control oil chamber is increased, the piston moves forward to the valve seat side, the valve body hits the valve seat, the outflow port is sealed, and the valve is closed.

  In the transmission using the above-described balance piston solenoid valve, when the hydraulic pressure in the hydraulic chamber in any pulley is increased or decreased, the control solenoid in the supply valve or discharge valve connected to the hydraulic chamber is energized. Then, opening control is performed, and the control oil chamber is communicated with the low pressure portion. As a result, the hydraulic pressure in the control oil chamber flows out to the low pressure portion through the control solenoid, but the flow rate is limited because the hydraulic pressure in the high pressure portion passes through the control orifice communicated with the control oil chamber. The oil pressure in the control oil chamber is maintained lower than the oil pressure in the oil chamber on the opposite side, and the main valve, which is a valve body integrated with the piston, is maintained in the open state. That is, in the above-described balance piston type solenoid valve, the hydraulic pressure in the control oil chamber is set according to the difference between the amount of hydraulic pressure passing through the control orifice and the amount of hydraulic pressure flowing through the control solenoid.

JP 2011-163508 A

  In the balance piston type solenoid valve, the control solenoid is basically configured to output a signal pressure to the control oil chamber, so that the control solenoid can be reduced in size. Therefore, the port that allows the control oil chamber to communicate with the low pressure portion and is opened and closed by the control solenoid becomes smaller in diameter with the downsizing of the control solenoid, and here, the throttle action (orifice effect) occurs. The shape or structure of the port (throttle section) where the throttle action occurs is mainly determined by the structure of the control solenoid. On the other hand, the shape or structure of the control orifice is mainly determined by the structure of the communication path in which the control orifice is provided and its workability or manufacturability. Therefore, the throttle action that occurs at the port in the control solenoid and the throttle action that occurs at the control orifice may differ depending on the state of the pressure oil. That is, the restriction of the flow rate due to the squeezing action is caused by the flow resistance against the pressure oil at the throttle portion, and the flow resistance is greatly influenced by the viscosity (viscous force) of the pressure oil. For this reason, in the transmission using the above-described balanced piston solenoid valve, the hydraulic pressure in the control oil chamber varies depending on whether the viscosity of the pressure oil is large or small, even if the current to the control solenoid is the same. As a result, there is a possibility that the controllability is deteriorated such that the desired control cannot be performed.

  The present invention has been made paying attention to the above technical problem, and stabilizes or improves the controllability of a transmission configured to control supply or discharge of hydraulic pressure by a balance piston type solenoid valve. An object of the present invention is to provide a hydraulic control device that can perform the above-described operation.

  In order to achieve the above object, a first aspect of the present invention provides a supply valve that selectively supplies the hydraulic pressure of a hydraulic source to a hydraulic chamber in which a transmission gear ratio or a transmission torque capacity changes as hydraulic pressure is supplied or discharged. And a discharge valve that selectively discharges hydraulic pressure from the hydraulic chamber, and at least one of the supply valve and the discharge valve has a piston part in which the inside of the cylinder portion that accommodates the piston is movable. The first oil chamber and the second oil chamber are divided into a first oil chamber and a second oil chamber, and the first oil chamber and the second oil chamber communicate with each other via a control orifice, and the inflow port communicated with the high pressure portion and the outflow communicated with the low pressure portion. A port is formed in the first oil chamber, and a valve body that opens and closes one of the inflow port and the outflow port is integrated with the piston, and the second oil chamber is selectively communicated with the low pressure portion. Control solenoid In a hydraulic control apparatus for a transmission configured by a balanced piston type valve provided with a valve, the control solenoid valve is configured so that an opening degree changes according to a control amount, and the control solenoid valve opens. The throttle portion formed by this is configured such that the increase amount of the flow resistance accompanying the increase in the viscosity of the hydraulic pressure is larger than the increase amount of the flow resistance at the control orifice, and the control amount of the control solenoid valve is increased. And a control amount setting means for setting the opening when the oil pressure is a predetermined temperature to a control amount that is larger than the opening when the oil pressure is higher than the predetermined temperature. It is characterized by being.

  The invention according to claim 2 is the invention according to claim 1, wherein the control solenoid valve includes a valve whose opening degree increases as the control amount increases, and the control amount setting means controls the control solenoid valve. A transmission hydraulic control apparatus comprising: means for increasing an amount when the temperature of the hydraulic pressure is a predetermined temperature compared to when the temperature of the hydraulic pressure is higher than the predetermined temperature.

  On the other hand, according to a third aspect of the present invention, in the first aspect of the invention, the control solenoid valve includes a valve whose opening degree decreases as the control amount increases, and the control amount setting means includes the control solenoid valve. And a means for reducing the control amount when the oil pressure temperature is a predetermined temperature as compared to when the oil pressure temperature is higher than the predetermined temperature. is there.

  According to a fourth aspect of the present invention, in the first or second aspect of the invention, the balance piston type valve includes a valve that is feedback-controlled based on a deviation between a target hydraulic pressure of the hydraulic chamber and a detected actual hydraulic pressure, The control amount setting means includes means for increasing a feedback gain that determines a control amount of the balance piston type valve when the temperature of the oil pressure is low compared to when the temperature of the oil pressure is high, and a target oil pressure of the hydraulic chamber. Means for increasing a correction amount for increasing the deviation from the detected actual oil pressure when the oil pressure is low compared to when the oil pressure is high; and a target oil pressure detected by the oil pressure chamber. Means for increasing the correction amount for increasing the control amount obtained based on the deviation from the oil pressure when the temperature of the oil pressure is low compared to when the temperature of the oil pressure is high. A hydraulic control device for a transmission, characterized in that it comprises or Re.

  According to a fifth aspect of the present invention, in the first or third aspect of the invention, the balance piston type valve includes a valve that is feedback-controlled based on a deviation between a target hydraulic pressure of the hydraulic chamber and a detected actual hydraulic pressure, The control amount setting means includes means for increasing a feedback gain that determines a control amount of the balance piston type valve when the temperature of the oil pressure is low compared to when the temperature of the oil pressure is high, and a target oil pressure of the hydraulic chamber. Means for increasing a correction amount for increasing the deviation from the detected actual oil pressure when the oil pressure is low compared to when the oil pressure is high; and a target oil pressure detected by the oil pressure chamber. Means for increasing a correction amount for decreasing and correcting the control amount obtained based on a deviation from the hydraulic pressure when the hydraulic pressure temperature is low compared to when the hydraulic pressure temperature is high. A hydraulic control device for a transmission, characterized in that it comprises or Re.

  According to the hydraulic control device of the present invention, when the opening degree of the control solenoid valve is as small as “0”, the second oil chamber is shut off from the low pressure portion, and the second oil chamber is blocked via the control orifice. Since the first oil chamber or the high pressure portion communicates with each other, the first oil chamber and the second oil chamber have the same hydraulic pressure. On the first oil chamber side, since the valve body is integrated with the piston, the pressure receiving area of the piston in the first oil chamber is smaller than the pressure receiving area in the second oil chamber, and as a result, the piston is on the first oil chamber side. The valve body closes the inflow port or the outflow port, and the balance piston type valve is closed. On the other hand, when the control amount of the control solenoid valve is set to a predetermined value and opened, the second oil chamber communicates with the low pressure portion, so that the oil pressure in the second oil chamber is lowered. That is, if the valve is a normally closed type valve, the control amount is increased. If the valve is a normally open type valve, the control amount is decreased, thereby reducing the hydraulic pressure in the second oil chamber. In that case, since the flow of hydraulic pressure from the first oil chamber to the second oil chamber is restricted by the control orifice, the hydraulic pressure in the second oil chamber is reduced to a pressure corresponding to the opening of the control solenoid valve. Due to the pressure difference between the first oil chamber and the second oil chamber generated in this way, the piston moves to the second oil chamber side and opens. That is, the hydraulic pressure is supplied to the hydraulic chamber through the inflow port and the outflow port, or discharged from the hydraulic chamber through the inflow port and the outflow port. Such a valve opening state is caused by the movement of the piston due to the pressure difference between the first oil chamber and the second oil chamber. The pressure difference is generated when the control solenoid valve is opened and the control orifice. This is caused by the difference in the flow rate of pressure oil between The flow resistance in the throttle portion generated when the control solenoid valve is opened increases when the temperature of the pressure oil decreases and its viscosity increases, and the amount of increase increases with the increase in the viscosity of the pressure oil. Greater than the increase in flow resistance at On the other hand, in the hydraulic control device of the present invention, when the viscosity of the pressure oil increases, the control solenoid valve is controlled to change its control amount and increase its opening as compared with the case where the viscosity is small. Therefore, even when the viscosity of the pressure oil increases, the amount of the pressure oil flowing through the throttle portion in the control solenoid valve can be secured to the same extent as when the viscosity is low. As a result, when the control solenoid valve is controlled to open, there is no significant difference between the amount of pressure oil flowing through the throttle and the control orifice when the pressure oil viscosity is small and large, and control of the control solenoid valve The relationship between the amount and the opening or flow rate of the balance piston valve does not vary with the viscosity of the pressure oil. Therefore, according to the hydraulic control device of the present invention, the controllability of the transmission can be prevented or suppressed from deteriorating, for example, the controllability of the transmission is changed by the viscosity of the pressure oil or the oil temperature, or the controllability of the transmission is improved. Can be improved.

  The correction in the present invention is a correction that reduces the influence of the above-described increase in viscosity, and specifically, a correction that increases the opening of the control solenoid valve. Therefore, the normal open type is a correction that increases the current that is the control amount, and the normal close type valve is a correction that decreases the current that is the control amount. Further, since the correction amount in the present invention is the amount of change in the control amount, the correction amount that is the amount of change is increased regardless of whether the current is increased or decreased.

It is a flowchart for demonstrating an example of the control performed with the hydraulic control apparatus which concerns on this invention. It is a figure which shows an example of the map which set the relationship with the oil temperature of the control gain. 1 is a diagram schematically showing a belt-type continuously variable transmission, a hydraulic control circuit thereof, and a control system that are objects of the present invention. It is a schematic diagram which shows in principle the structure of the balance piston type valve which comprises the supply valve or the discharge valve. It is explanatory drawing explaining the relationship between the control orifice, the 2nd oil chamber, and control pressure.

  The transmission targeted in the present invention is a transmission whose transmission ratio and transmission torque capacity are controlled by hydraulic pressure. Therefore, the transmission in this invention is a conventionally known stepped transmission or continuously variable transmission for vehicles. It may be a machine. Among them, the transmission whose hydraulic pressure variation immediately affects the gear ratio is a belt-type or toroidal-type continuously variable transmission, and therefore the present invention is suitable for a hydraulic control device for these continuously variable transmissions. Can be applied to.

  FIG. 3 schematically shows a belt type continuously variable transmission and a hydraulic circuit for setting the gear ratio and belt clamping pressure. The belt type continuously variable transmission 1 includes a driving pulley (primary pulley) 2 to which torque of a driving force source (not shown) such as an engine is transmitted, and an output member (not shown) such as an output shaft and an output gear. A belt 4 is wound around a driven pulley (secondary pulley) 3 that outputs torque, and the torque is transmitted between the pulleys 2 and 3 via the belt 4. Each of the pulleys 2 and 3 is configured to be able to change the width of the belt groove around which the belt 4 is wound. Specifically, the primary pulley 2 approaches and separates from the fixed sheave 2A and the fixed sheave 2A. The movable sheave 2B is moved to the fixed sheave 2A side by the hydraulic pressure supplied to or discharged from the hydraulic chamber 2C provided on the back side of the movable sheave 2B. Alternatively, it is configured to be separated from the fixed sheave 2A. Similarly, the secondary pulley 3 is constituted by a fixed sheave 3A and a movable sheave 3B arranged so as to be able to approach and separate from the fixed sheave 3A, and is provided on the back side of the movable sheave 3B. The movable sheave 3B is moved to the fixed sheave 3A side or separated from the fixed sheave 3A by the hydraulic pressure supplied to or discharged from the hydraulic chamber 3C. The belt 4 is sandwiched between the sheaves 3A and 3B by the hydraulic pressure supplied to the hydraulic chamber 3C of one of the pulleys (for example, the secondary pulley 3), and the belt 4 and the sheaves 3A and 3B are sandwiched by the clamping pressure. A transmission torque capacity corresponding to the frictional force is set. In this state, each pulley of the belt 4 is changed by changing the interval (groove width) between the sheaves 2A and 2B by supplying or discharging the hydraulic pressure to the hydraulic chamber 2C of the other pulley (for example, the primary pulley 2). The wrapping radius with respect to 2 and 3 is changed to cause a shift.

  The hydraulic pressures of the hydraulic chambers 2C and 3C in the pulleys 2 and 3 are configured to be controlled by appropriately supplying and discharging the hydraulic pressure. The original pressure is the hydraulic pressure of a hydraulic source 5 such as an oil pump or an accumulator. When an oil pump is used as the hydraulic source 5, the oil pump is a so-called mechanical oil pump or motor driven by the driving force source. It may be an electric oil pump that is driven. A supply oil passage (or line pressure oil passage) 7 communicated with the hydraulic power source 5 through the check valve 6 is communicated with each of the hydraulic chambers 2C and 3C and communicated with the hydraulic chamber 2C of the primary pulley 2. A supply valve 8 is provided in the supply oil passage 7, and the supply valve 8 is controlled to be opened and closed, whereby the hydraulic pressure is supplied to the hydraulic chamber 2 </ b> C and the supply of the hydraulic pressure is shut off. Similarly, a supply valve 9 is provided in the supply oil passage 7 communicated with the hydraulic chamber 3C of the secondary pulley 3, and the supply valve 9 is controlled to open and close to supply hydraulic pressure to the hydraulic chamber 3C. Is configured to shut off the supply. Further, a discharge valve 10 communicates with the hydraulic chamber 2C of the primary pulley 2. By controlling the opening and closing of the discharge valve 10, the hydraulic pressure is discharged from the hydraulic chamber 2C to a predetermined drain location, and the discharge of the hydraulic pressure is shut off. Is configured to do. Similarly, a discharge valve 11 is communicated with the hydraulic chamber 3C of the secondary pulley 3. By controlling the discharge valve 11, the hydraulic pressure is discharged from the hydraulic chamber 3C to a predetermined drain location. It is configured to shut off the discharge of hydraulic pressure.

  The supply valves 8 and 9 and the discharge valves 10 and 11 are electrically controlled solenoid valves that are controlled to open and supply and discharge hydraulic pressure, but are themselves valves without a pressure regulating function. is there. Therefore, the supply valves 8 and 9 and the discharge valves 10 and 11 are feedback-controlled based on the pressure deviation between the target pressure and the actual oil pressure, so that the oil pressure in the hydraulic chambers 2C and 3C is controlled to the target oil pressure. It is configured. Various sensors for obtaining data for the control are provided. For example, a line pressure sensor 12 that detects a line pressure Pl that is a source pressure and outputs a signal, and a hydraulic chamber 2C of the primary pulley 2 is provided. A primary hydraulic sensor 13 for detecting the hydraulic pressure Ppri and outputting a signal, and a secondary hydraulic sensor 14 for detecting the hydraulic pressure Psec of the hydraulic chamber 3C of the secondary pulley 3 and outputting the signal are provided. Further, a primary rotational speed sensor 15 that detects the rotational speed Npri of the primary pulley 2 and outputs a signal, and a secondary rotational speed sensor 16 that detects the rotational speed Nsec of the secondary pulley 3 and outputs a signal are provided. .

  An electronic control unit (ECU) 17 for controlling the supply valves 8 and 9 and the discharge valves 10 and 11 is provided. The electronic control unit 17 is mainly composed of a microcomputer, performs computations using various input data and data stored in advance, and outputs the computation results as control command signals. It is configured. Therefore, the electronic control unit 17 includes data detected by the sensors 12 to 16, that is, the line pressure Pl, the hydraulic pressure Ppri of the hydraulic chamber 2C of the primary pulley 2, the hydraulic pressure Psec of the hydraulic chamber 3C of the secondary pulley 3, The rotational speeds Npri and Nsec of the pulleys 2 and 3 are input.

  In the hydraulic control apparatus according to the present invention, at least one of the supply valve and the discharge valve is constituted by a balance piston type valve. In the hydraulic circuit shown in FIG. , 11 are constituted by balanced piston type valves. In the example shown in FIG. 3, each balance piston type valve has the same configuration, and the configuration will be described with reference to FIG. In the following description of the balance piston type valve, the hydraulic source 5 or the line pressure Pl for the supply valves 8 and 9 is the high pressure section, the hydraulic chambers 2C and 3C are the low pressure section, and the hydraulic chamber 2C and the discharge valves 10 and 11 are the hydraulic chamber 2C, 3C is described as a high pressure part, and a drain location is described as a low pressure part.

  In FIG. 4, a piston 22 integral with the valve body 21 is accommodated inside a cylinder portion 23 so as to be movable back and forth. Therefore, the inside of the cylinder portion 23 is partitioned into two oil chambers 24 and 25 by the piston 22, and the oil chamber 24 in which the valve body 21 is accommodated is included in the oil chamber 24 and 25. An inflow port 27 to which hydraulic pressure is supplied and an outflow port 29 through which the hydraulic pressure flows out toward the low pressure portion 28 are formed. The outflow port 29 is formed in the end plate portion on the distal end side of the valve body 21 so that the outflow port 29 is closed when the valve body 21 abuts and the outflow port 29 is opened when the valve body 21 is retracted. It is configured. Further, a spring 30 that presses the piston 22 toward the outflow port 29 is disposed in the oil chamber 25 on the opposite side of the piston 22 with respect to the oil chamber 24 in which the valve body 21 is accommodated. A port 31 is formed. The signal pressure port 31 and the inflow port 27 are communicated with each other by a communication path 33 having a control orifice 32. The control orifice 32 is for restricting the flow rate by restricting the pressure oil flowing from the high pressure portion 26 or the oil chamber 24 toward the oil chamber 25, and for example, a thin plate material having a minute through hole, It is formed so as to cross the communication path 33. The communication passage 33 is mainly for communicating the oil chambers 24 and 25, and therefore may be formed so as to penetrate the piston 22 in the axial direction or the inner surface of the cylinder portion 23. It may be formed.

  Further, a control solenoid valve 34 for selectively communicating the oil chamber 25 in which the spring 30 is disposed with the low pressure portion 28 is provided. More specifically, an outflow port 35 is formed in the oil chamber 25, and a control solenoid valve 34 is connected to the outflow port 35. The control solenoid valve 34 includes an electromagnetic coil 38 that generates an electromagnetic force that pushes the valve body 36 axially by a spring 37 and pulls the valve body 36 axially against the spring 37. Yes. Further, an inflow port 39 communicating with the outflow port 35 is formed on the distal end side of the valve body 36, and the opening end of the inflow port 39 is a valve seat, and the distal end of the valve body 36 is at the open end. The inflow port 39 is hermetically sealed when the parts abut against each other, and the inflow port 39 is opened when the valve body 36 is separated, and the degree of opening according to the amount of current supplied to the electromagnetic coil 38 is set. ing. Furthermore, the outflow port 40 which connects the location in which the valve body 36 is accommodated to the low voltage | pressure part 28 is formed.

The operation of the balance piston type valve will be described. First, the axial force acting on the piston 22 and the valve body 21 integrated therewith is as follows. The force acting in the right direction in FIG. 4 is generated by the oil pressure Ps of the oil chamber 25 (hereinafter also referred to as the second oil chamber) in which the signal pressure port 31 is formed, and the pressure receiving area in the piston 22. Is As, the axial force directed to the right is “Ps × As”. Further, since the forces acting in the left direction in FIG. 4 are the oil pressure Pl of the high pressure portion 26 and the oil pressure Pr of the low pressure portion 28, assuming that the respective pressure receiving areas are Am and Ar, the axial force directed in the left direction is “P1 × Am + Pr × Ar”. The pressure receiving area Am on which the hydraulic pressure Pl of the high pressure portion 26 acts is an area obtained by subtracting the cross sectional area of the valve body 21 from the cross sectional area of the piston 22, and the pressure receiving area Ar on which the hydraulic pressure Pr of the low pressure portion 28 acts is almost equal. It is a cross-sectional area of the outflow port 29. If the right direction in FIG. 4 is a negative direction and the elastic force of the spring 30 is ignored, the axial force acting on the piston 22 and the valve body 21 integrated therewith is
−Ps × As + Pl × Am + Pr × Ar
It becomes. Therefore, when the control solenoid valve 34 is energized and controlled to open, the hydraulic pressure Ps of the second oil chamber 25 is lowered, and the piston 22 moves to the second oil chamber 25 side. Along with this, the valve body 21 opens away from the open end (that is, the valve seat) of the outflow port 29. That is, pressure oil flows from the high pressure portion 26 to the low pressure portion 28.

  The hydraulic pressure Ps of the second oil chamber 25 when operating in this way is the amount of pressure oil Qc supplied from the high pressure section 26 to the second oil chamber 25 through the control orifice 32 and the control solenoid valve 34. It is proportional to the difference (Qc−Qs) from the amount Qs of pressure oil discharged to the low pressure section 28. This relationship is schematically shown in FIG. The flow rate Qc of the pressure oil flowing from the high pressure portion 26 to the second oil chamber 25 is restricted by the control orifice 32. Further, the flow rate Qs of the pressure oil flowing from the second oil chamber 25 to the low pressure portion 28 is small when the control solenoid valve 34 does not need to flow a large amount of pressure oil. Since the area is small, the flow rate is restricted due to the throttling action of the portion (throttle portion).

  As described above, the control orifice 32 has a structure with almost no length in the streamline direction, such as being formed by piercing a thin plate material with a minute through-hole due to a demand for manufacturability and the like. The shape is depicted schematically in FIG. In contrast, the opening through which the control solenoid valve 34 opens and pressure oil flows through the valve body 36 is a convex surface and the valve seat is used as a valve seat to secure the sealed state by abutting the valve body 36. By forming a corresponding concave surface, the shape has a certain length in the flow direction of the pressure oil. This is shown schematically in FIG. Therefore, the flow of the pressure oil is restricted by the control orifice 32, but the resistance received while passing through the control orifice 32 is small. On the other hand, the flow of the pressure oil is restricted by the opening of the control solenoid valve 34. At the same time, the flow resistance that hinders the flow of pressure oil is greater than that at the control orifice 32. Since the flow resistance changes depending on the viscosity of the pressure oil, the flow difficulty when the pressure oil is high, that is, the influence of the viscosity on the flow rate is greater in the control solenoid valve 34 than in the control orifice 32.

  Therefore, in the balance piston type valve described above, when the viscosity of the pressure oil is increased due to low oil temperature or the like, the hydraulic pressure is supplied from the second oil chamber 25 to the low pressure portion 28 as compared with the case where the viscosity is small. Is difficult to be discharged. Therefore, when the viscosity of the pressure oil is large, even if the control solenoid valve 34 is controlled to open, the hydraulic pressure in the second oil chamber 25 is difficult to decrease, causing a delay in the opening operation of the balance piston valve, or a low pressure. In some cases, the flow rate of the pressure oil toward the portion 28 is not sufficient. In the transmission described above, this is a factor such as belt slippage due to a decrease in shift response and insufficient belt clamping pressure.

  The hydraulic control device according to the present invention reduces the influence of the oil temperature or the viscosity of the pressure oil described above, and maintains the hydraulic controllability of the transmission in a good state. The control for that purpose is control for changing the control amount of the control solenoid valve 34 in accordance with the oil temperature related to the viscosity of the pressure oil, and an example thereof is shown in the flowchart of FIG. The supply valves 8 and 9 and the discharge valves 10 and 11 constituted by the balance piston type valve having the configuration shown in FIG. 4 obtain the target pressures of the hydraulic chambers 2C and 3C, which are control target portions, Feedback control is performed so that the hydraulic pressure (control pressure) becomes the target pressure. For example, if the control pressure is lower than the target pressure, the supply valves 8 and 9 are controlled to open, and the hydraulic pressure of the hydraulic source 5 is supplied to the hydraulic chambers 2C and 3C. Further, if the control pressure is higher than the target pressure, the discharge valves 10 and 11 are controlled to be opened and discharged from the hydraulic chambers 2C and 3C. The control amount in each case is obtained based on the pressure deviation between the target pressure and the control pressure and a predetermined control gain.

  In performing such feedback control, the routine shown in FIG. 1 is repeatedly executed every predetermined short time. First, the target pressure Po, the control pressure Pr, the supply pressure Pl, and the control oil temperature Toil are calculated (step). S1, S2, S3, S4). The calculation of these data may be performed in the order shown in FIG. 1, may be performed in a different order, or may be performed in parallel. The target pressure P0 is a hydraulic pressure for setting a target gear ratio for the hydraulic chamber 2C of the primary pulley 2, and the target gear ratio is the optimum for the required driving amount such as the accelerator opening, the vehicle speed, and the driving force source. Therefore, the target hydraulic pressure Po for the hydraulic chamber 2C of the primary pulley 2 can be determined based on the target gear ratio, the ratio of axial thrusts of the primary pulley 2 and the secondary pulley 3, and the like. be able to. The hydraulic pressure in the hydraulic chamber 3C of the secondary pulley 3 is a hydraulic pressure that generates a belt clamping pressure and is used to set a transmission torque capacity. Can be based on. The control pressure Pr, the supply pressure Pl, and the control oil temperature Toil may be values detected by sensors.

  Next, a control gain Pfb is obtained (step S5). The control gain Pfb is a coefficient of a proportional term, a differential term or an integral term in the feedback control, and is set in advance so that a control response delay does not occur in particular and control hunting does not occur. Then, the control gain Pfb is set to a value corresponding to the oil temperature Toil in addition to the supply pressure Pl and the control pressure Pr. Specifically, when the oil temperature Toil is lower than a predetermined temperature, the control gain Pfb is set to a larger value as the oil temperature Toil is lower, and an example thereof is schematically shown in FIG. The predetermined temperature is a temperature determined as an increase in the viscosity of the pressure oil starts to affect the controllability of the hydraulic pressure, and can be determined in advance by an experiment or the like. The reason why the control gain Pfb is increased on the low oil temperature side is to compensate for an increase in the control amount to increase the viscosity of the pressure oil and reduce its fluidity. Therefore, the oil temperature Toil or If the viscosity of the pressure oil does not particularly affect the controllability, the control gain Pfb is maintained at a value set in the prior art, and is set to a larger value as the temperature becomes lower or higher. Finally, the upper limit is set and maintained. That is, the control gain Pfb is increased in the present invention when the increase in the viscosity of the pressure oil accompanying the decrease in the oil temperature Toil affects the controllability. As the control gain Pfb, a control gain Pfbu for the supply valves 8 and 9 and a control gain Pfbd for the discharge valves 10 and 11 are obtained, respectively.

  On the other hand, a pressure deviation DP (= P0−Pr) is calculated from the target pressure P0 and the control pressure Pr (step S6). Based on the pressure deviation DP and the control gain Pfb, the control amount Isolu of the supply valves 8 and 9 is calculated (step S7), or the control amount Isold of the discharge valves 10 and 11 is calculated (step S8). ). These control amounts Isolu and Isold are, for example, current values, and the relationship between the current value and the opening (or opening diameter) is determined by the configuration of the control solenoid valve 34. Therefore, the relationship is prepared in advance as an arithmetic expression or a map. Can be kept. Therefore, the control in step S7 and step S8 can be calculated from the map using, for example, the control gain Pfb and the pressure deviation DP as arguments. The parameters for calculating the control amount require the control gain Pfb and the pressure deviation DP described above, but the supply pressure Pl is added to this, or a speed change mode such as a manual mode or an automatic mode is added, A driving mode such as a mode or a normal mode may be added. That is, correction such as giving priority to control responsiveness or giving priority to control stability may be added.

  Then, the control amounts Isolu, Isold calculated in Step S7 or Step S8 are outputted as control command signals (Step S9), and the supply valves 8, 9 or the discharge valves 10, 11 correspond to the control amounts Isolu, Isold. The opening is controlled. More specifically, the control solenoid valve 34 in the balance piston type valve constituting each of the supply valves 8 and 9 and the discharge valves 10 and 11 is energized, and the control solenoid valve 34 opens according to the current. .

  In that case, if the oil temperature Toil is lower than the steady temperature, the control gain Pfb is increased according to the oil temperature Toil as described above. It is increased compared to the high temperature case. Therefore, when the opening degree of the control solenoid valve 34 is low (when the viscosity of the pressure oil is high), the flow resistance (or difficulty of flow) accompanying the increase in the viscosity of the pressure oil is increased by the increase in the opening degree. Compensated or corrected. As a result, even if the temperature of the pressure oil is low and the viscosity thereof is high, the pressure oil flows without being particularly affected by the increase in the viscosity of the control orifice 32, and in the control solenoid valve 34 controlled to open, The opening degree is increased in response to the increased viscosity due to the lower temperature of the pressure oil, and the pressure is increased substantially without being affected by the increase in the viscosity of the pressure oil or with the effect reduced. Oil flows. As described above, even if the influence of the oil temperature Toil or the viscosity of the pressure oil on the flow of the pressure oil is different between the control orifice 32 and the control solenoid valve 34, such a pressure is applied in the hydraulic control device according to the present invention. The change of the oil flow characteristics based on the oil temperature Toil can be compensated or corrected by changing the control amount. Specifically, since the hydraulic pressure is discharged from the second oil chamber 25 via the control solenoid valve 34 as expected, the hydraulic pressure in the second oil chamber 25 can be reduced to the desired hydraulic pressure. The valve body 21 and the piston 22 integrated with the valve body 21 can be moved backward as expected, and the hydraulic pressure can flow from the high pressure portion 26 toward the low pressure portion 28 without excess or deficiency. Therefore, according to the hydraulic control device according to the present invention, even if the viscosity of the pressure oil increases, such as the oil temperature Toil decreases, the hydraulic response can be maintained at the same level as the normal state, and the controllability of the transmission decreases. Can be avoided or suppressed.

  The present invention only needs to be configured to increase the opening of the control solenoid valve 34 when the temperature of the pressure oil is low or the viscosity thereof increases. In addition to increasing the control gain Pfb according to the decrease in the oil temperature, the pressure deviation DP is corrected to increase according to the decrease in the oil temperature, or the control amount obtained based on the control gain Pfb and the pressure deviation DP. You may carry out by correct | amending. Therefore, the functional means for executing the control in step S5 described above corresponds to the control amount setting means in the present invention. Further, in the present invention, it is not necessary that all of the supply valves 8 and 9 and the discharge valves 10 and 11 are constituted by the balance piston type valve, and at least one of the supply valves 8 and 9 and the discharge valves 10 and 11 is not required. One should just be comprised by the balance piston type valve | bulb. The above specific example is based on a normally closed type valve. However, the present invention is not limited to the above specific example, and may be applied to a hydraulic control device using a normal open type valve. Can do. Therefore, in this case, the control amount of the control solenoid valve is decreased when the opening degree is increased, and the current value is decreased. In any case, in the present invention, when it is considered that the oil pressure has increased due to a decrease in the oil temperature, control is performed to increase the opening of the control solenoid valve as compared with the case where the oil temperature is low. In addition, correction for that is performed.

  DESCRIPTION OF SYMBOLS 1 ... Belt type continuously variable transmission, 2 ... Drive pulley (primary pulley), 3 ... Driven pulley (secondary pulley), 4 ... Belt, 2A ... Fixed sheave, 2B ... Movable sheave, 2C ... Hydraulic chamber, 3A ... Fixed sheave 3B ... movable sheave, 3C ... hydraulic chamber, 5 ... hydraulic power source, 7 ... supply oil passage (or line pressure oil passage), 8 ... supply valve, 9 ... supply valve, 10 ... discharge valve, 11 ... discharge valve, 12 DESCRIPTION OF SYMBOLS ... Line pressure sensor, 13 ... Primary oil pressure sensor, 14 ... Secondary oil pressure sensor, 15 ... Primary rotation speed sensor, 16 ... Secondary rotation speed sensor, 17 ... Electronic control unit (ECU), 21 ... Valve body, 22 ... Piston, 23 ... Cylinder part, 24, 25 ... Oil chamber, 26 ... High pressure part, 27 ... Inflow port, 28 ... Low pressure part, 29 ... Outlet port, 31 ... Signal pressure port, 32 ... Control orifice, 33 ... Communication path, 34 ... Control solenoid valve, 35 ... Outlet port, 36 ... Valve element, 37 ... Spring, 38 ... Electromagnetic coil, 39 ... Inlet port, 40 ... Outlet port, Ppri ... (Primary pulley Hydraulic pressure (in the hydraulic chamber), Psec (hydraulic chamber in the secondary pulley).

Claims (5)

There are a supply valve for selectively supplying the hydraulic pressure of the hydraulic source to a hydraulic chamber whose transmission gear ratio or transmission torque capacity is changed by supplying or discharging the hydraulic pressure, and a discharge valve for selectively discharging the hydraulic pressure from the hydraulic chamber. At least one of the supply valve and the discharge valve is communicated, and the inside of the cylinder portion that accommodates the piston so as to be movable back and forth is partitioned into a first oil chamber and a second oil chamber by the piston. The first oil chamber and the second oil chamber are communicated with each other through a control orifice, and an inflow port communicated with the high pressure portion and an outflow port communicated with the low pressure portion are formed in the first oil chamber. A balance piston type valve in which a valve body that opens and closes one of the outflow ports is integrated with the piston, and a control solenoid valve that selectively communicates the second oil chamber to the low pressure portion is provided. In the hydraulic control apparatus for a transmission that is configured by,
The control solenoid valve is configured to change the opening according to the control amount,
The throttle portion formed by opening the control solenoid valve is configured such that the amount of increase in flow resistance that accompanies an increase in hydraulic viscosity is greater than the amount of increase in flow resistance at the control orifice,
The control amount of the control solenoid valve is set to a control amount in which the opening degree when the oil pressure temperature is a predetermined temperature is larger than the opening degree when the oil pressure temperature is higher than the predetermined temperature. A hydraulic control apparatus for a transmission, comprising control amount setting means for performing transmission. The control solenoid valve includes a valve whose opening degree increases as the control amount increases,
The control amount setting means includes means for increasing the control amount of the control solenoid valve when the temperature of the hydraulic pressure is a predetermined temperature compared to when the temperature of the hydraulic pressure is higher than the predetermined temperature. The hydraulic control apparatus for a transmission according to claim 1. The control solenoid valve includes a valve whose opening degree decreases as the control amount increases,
The control amount setting means includes means for reducing the control amount of the control solenoid valve when the temperature of the hydraulic pressure is a predetermined temperature compared to when the temperature of the hydraulic pressure is higher than the predetermined temperature. The hydraulic control apparatus for a transmission according to claim 1. The balance piston type valve includes a valve that is feedback-controlled based on a deviation between a target hydraulic pressure of the hydraulic chamber and a detected actual hydraulic pressure,
The control amount setting means includes means for increasing a feedback gain that determines the control amount of the balance piston type valve when the temperature of the oil pressure is low compared to when the temperature of the oil pressure is high, and a target oil pressure of the hydraulic chamber And a means for increasing the correction amount for increasing the deviation from the detected actual hydraulic pressure when the temperature of the hydraulic pressure is low compared to when the temperature of the hydraulic pressure is high, and the target hydraulic pressure of the hydraulic chamber is detected And a means for increasing a correction amount for increasing the control amount obtained based on a deviation from the actual oil pressure when the temperature of the oil pressure is low compared to when the temperature of the oil pressure is high. The hydraulic control device for a transmission according to claim 1 or 2. The balance piston type valve includes a valve that is feedback-controlled based on a deviation between a target hydraulic pressure of the hydraulic chamber and a detected actual hydraulic pressure,
The control amount setting means includes means for increasing a feedback gain that determines the control amount of the balance piston type valve when the temperature of the oil pressure is low compared to when the temperature of the oil pressure is high, and a target oil pressure of the hydraulic chamber And a means for increasing the correction amount for increasing the deviation from the detected actual hydraulic pressure when the temperature of the hydraulic pressure is low compared to when the temperature of the hydraulic pressure is high, and the target hydraulic pressure of the hydraulic chamber is detected And means for increasing a correction amount for reducing and correcting the control amount obtained based on a deviation from the actual hydraulic pressure when the temperature of the hydraulic pressure is low compared to when the temperature of the hydraulic pressure is high. 4. The hydraulic control device for a transmission according to claim 1 or 3, wherein:

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