JP2008175319A - Hydraulic control device for transmission - Google Patents

Abstract

An object of the present invention is to provide a transmission hydraulic control device capable of stably controlling a control hydraulic pressure supplied to an object to be controlled even when characteristics of a signal pressure electromagnetic valve change.
A hydraulic pressure generated by an oil pump is regulated to a line pressure by a first pressure regulating valve having an output pressure of a first electromagnetic valve as a signal pressure, and the line pressure is adjusted to a second electromagnetic valve. In the transmission hydraulic control apparatus configured to reduce the pressure by the second pressure regulating valve 35 using the output pressure of 46 as a signal pressure and supply the pressure to the hydraulic actuator 6, the first electromagnetic valve 34 to the first A first signal pressure oil passage 48 for applying the signal pressure to the pressure regulating valve 23, and a second signal pressure for applying the signal pressure from the second electromagnetic valve 46 to the second pressure regulating valve 35. A signal pressure oil passage 49 and oil pressure compensation circuits 50 and 51 for compensating the oil pressure in the first signal pressure oil passage 48 to be equal to or higher than the oil pressure in the second signal pressure oil passage 49 are provided.
[Selection] Figure 1

Description

  The present invention relates to a hydraulic control device in a transmission that controls transmission of torque by hydraulic pressure.

  The transmission can change the gear ratio by changing the gear pair involved in torque transmission, changing the position of the torque transmission point in the friction wheel in the radial direction, changing the winding effective radius of a winding transmission member such as a belt, etc. Is configured to change. Such a shift by changing the torque transmission path or the like is configured to be controlled by hydraulic pressure in an automatic or semi-automatic transmission. Further, a friction type clutch in which a transmission torque capacity is set by hydraulic pressure may be used for torque input and output to the transmission. Furthermore, in the toroidal type continuously variable transmission, torque is transmitted by the shearing force of the traction oil, and in the belt type continuously variable transmission, torque is transmitted by the frictional force between the pulley and the belt. Is determined by the roller pressing force by which each disk on the input / output side clamps the roller and the belt clamping force by which the pulley clamps the belt.

  Therefore, in a transmission for a vehicle, a line pressure corresponding to a torque input from a power source such as an engine is generated, and a roller pressing force, a clutch engagement force, and the like are set using the line pressure as a source pressure. . An example of this is described in Patent Document 1. The device described in Patent Document 1 is a hydraulic control device in a belt-type continuously variable transmission, and the hydraulic pressure command value of a linear solenoid for line pressure control is expressed as a line pressure. It is configured to adjust the line pressure by supplying it to the control unit, and to adjust the belt clamping pressure by supplying the hydraulic pressure command value of the linear solenoid for clamping pressure control to the clamping pressure control unit. That is, the line pressure and the belt clamping pressure are respectively controlled using individual linear solenoids and a control unit.

  Patent Document 2 describes a speed change control device for a continuously variable transmission configured to control a belt clamping pressure using a line pressure as an original pressure. In the device described in Patent Document 2, when the gear is suddenly changed, the pressure oil is temporarily confined in the cylinder of the driven pulley, and this prevents the belt clamping pressure from becoming higher than the line pressure. For this purpose, a one-way valve that opens only in one direction from the driven pulley cylinder toward the line pressure oil passage is provided.

JP 2005-163934 A Japanese Utility Model Publication No. 61-133155

  As described in Patent Document 1 above, in order to adjust the line pressure, the belt clamping pressure, and the like, the output pressure of the solenoid may be supplied as a signal pressure to the pressure control unit. The signal pressure is the pressure corresponding to the current value or duty signal applied to the solenoid, but the relationship between the current value or signal and pressure is determined by the characteristics of the solenoid, but the characteristics change over time In some cases, the signal pressure supplied to the pressure control unit becomes higher than the intended pressure, or on the contrary. As a result, the line pressure and the control hydraulic pressure set using this as the source pressure may be distorted.

  For example, when the pressure control unit is configured to adjust the signal pressure and the feedback pressure of the output pressure by opposing the spool, the line pressure becomes relatively low or the control is performed. When the hydraulic pressure becomes relatively high, the difference between the control hydraulic pressure to be set and the line pressure disappears, so the spool of the spool valve for setting the control hydraulic pressure is fixed to one end of the movable range. It becomes a state. When the line pressure increases from that state, or when the control hydraulic pressure to be set increases, the spool moves to obtain the control hydraulic pressure by controlling the line pressure to be reduced, but there is an overshoot that causes the spool to move excessively. In order to correct this, the spool moves again in the opposite direction, and overshoot may occur at that time. As a result, hunting in which the control oil pressure repeatedly fluctuates in level occurs, and control may become transiently unstable. When the belt clamping pressure is set by the control hydraulic pressure or when the roller pressing force is set in the toroidal type continuously variable transmission, the belt clamping pressure or the roller pressing force temporarily decreases, and slipping occurs at that time. There was a possibility that wear of the continuously variable transmission would progress.

  The present invention has been made paying attention to the above technical problem, and even if the signal pressure for pressure adjustment fluctuates from the intended pressure, the line pressure is controlled to be reduced and supplied to the hydraulic actuator. It is an object of the present invention to provide a hydraulic control device capable of stably controlling the controlled hydraulic pressure.

  In order to achieve the above object, the invention according to claim 1 is characterized in that the hydraulic pressure generated by the oil pump is lined by the first pressure regulating valve that uses the output pressure of the first electromagnetic valve that is electrically controlled as the signal pressure. The line pressure is regulated by a second pressure regulating valve that uses the output pressure of the second electromagnetic valve that is electrically controlled as a signal pressure and supplied to a predetermined hydraulic actuator. In the transmission hydraulic control apparatus, a first signal pressure oil passage for applying the signal pressure from the first electromagnetic valve to the first pressure regulating valve, and a second signal from the second electromagnetic valve. The second signal pressure oil passage for applying the signal pressure to the pressure regulating valve and the oil pressure in the first signal pressure oil passage are compensated to be equal to or higher than the oil pressure in the second signal pressure oil passage. And a hydraulic pressure compensation circuit.

  According to a second aspect of the invention, in the first aspect of the invention, the hydraulic pressure compensation circuit is closed when the hydraulic pressure in the first signal pressure oil path is higher than the hydraulic pressure in the second signal pressure oil path, and The first signal pressure oil passage and the second signal pressure oil passage are opened via a check valve that opens when the oil pressure in the first signal pressure oil passage is lower than the oil pressure in the second signal pressure oil passage. The transmission hydraulic control device includes an oil passage communicating with the transmission.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the first electromagnetic valve and the second electromagnetic valve are valves having the same specifications and configuration. Device.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the first pressure regulating valve and the second pressure regulating valve oppose the signal pressure using the output pressure as a feedback pressure across a spool. The transmission hydraulic control device includes a spool valve that regulates pressure.

  According to the first aspect of the invention, the second signal pressure is compensated by the hydraulic pressure compensation circuit so that the second signal pressure is equal to or lower than the first signal pressure. Therefore, even if the characteristics of any of the solenoid valves change or some kind of failure occurs, the second pressure regulating valve operates so as to regulate the hydraulic pressure higher than the line pressure. It is possible to prevent or avoid such a situation that the control of the hydraulic pressure by the pressure valve becomes unstable.

  According to the invention of claim 2, the signal pressure by the first electromagnetic valve for regulating the line pressure is relatively lower than the second signal pressure by the second electromagnetic valve for controlling the pressure reduction of the line pressure. When this happens, the check valve opens to at least balance each signal pressure. Therefore, it is possible to prevent or avoid a situation in which the second pressure regulating valve operates so as to regulate the hydraulic pressure higher than the line pressure, or the hydraulic pressure control by the first pressure regulating valve becomes unstable accordingly. Can do.

  According to the invention of claim 3, since the same solenoid valve can be used for the first solenoid valve and the second solenoid valve, the number of parts can be reduced to improve the production and assembly, and the low Cost can be reduced.

  According to the invention of claim 4, the same effect as that of the inventions of claims 1 to 3 described above can be obtained by using a spool valve generally used in a hydraulic control device for a transmission.

  Next, the present invention will be described based on specific examples. The hydraulic control device according to the present invention is intended for a transmission, and the transmission is a typical example of an automatic transmission for a vehicle, but is a transmission other than a transmission for a vehicle. Also good. The automatic transmission for the vehicle may be either a stepped transmission or a continuously variable transmission. In short, the hydraulic pressure generated by the oil pump is regulated to the line pressure, and the line pressure is reduced. Any transmission that is configured to be controlled and supplied to a predetermined hydraulic actuator may be used. Therefore, the hydraulic actuator engages a hydraulic cylinder for pressing a power roller in a toroidal type continuously variable transmission, an actuator for generating belt clamping pressure in a belt type continuously variable transmission, a friction clutch and a friction brake. It may be a hydraulic cylinder or the like.

  FIG. 2 schematically shows the overall configuration of the toroidal-type continuously variable transmission. The input disk 1 and the output disk 2 with the toroidal surfaces facing each other are arranged in two pairs on the same axis. Yes. In the examples shown in these drawings, the input disks 1 are arranged at both the left and right ends in the axial direction, the output disks 2 are arranged in a so-called back-to-back manner, and an output member between these output disks 2 is used. An output gear 3 is arranged.

  The input shaft 4 passes through the center of each of the disks 1 and 2 and the output gear 3, and each input disk 1 is attached to the input shaft 4 so as to rotate integrally and move in the axial direction. Yes. On the other hand, the output disk 2 and the output gear 3 are rotatably fitted to the input shaft 4, and each output disk 2 and the output gear 3 are connected so as to rotate together. Yes. A lock nut 5 as a lock member for preventing the input disk 1 from coming off is attached to one end of the input shaft 4 (the left end in FIG. 2). A hydraulic cylinder 6 is attached to the opposite end (the right end in FIG. 2).

  The hydraulic cylinder 6 is a pressing force generating mechanism for generating a roller pressing force that presses each pair of the input disk 1 and the output disk 2 toward each other, and corresponds to the hydraulic actuator in the present invention. 7 is fixed to the input shaft 4, and a piston 8 accommodated in the cylinder 7 so as to be movable in the axial direction is brought into contact with the back surface of the input disk 1. Accordingly, by supplying hydraulic pressure between the cylinder 7 and the piston 8, the piston 8 presses one input disk 1 toward the input disk 1 disposed on the opposite side. Has been. The hydraulic pressure supplied to the hydraulic cylinder 6 is a hydraulic pressure that is pressure-reduced according to the torque transmitted to the input shaft 4 using the line pressure as the original pressure.

  A plurality of power rollers 9 are sandwiched between each pair of input disk 1 and output disk 2. These power rollers 9 are so-called transmission members that mediate the transmission of torque between the input disk 1 and the output disk 2, have a substantially disk shape, and between the input disk 1 and the output disk 2, The disks 1 and 2 are arranged at equal intervals in the circumferential direction. Each power roller 9 is held by a trunnion 10 so as to rotate as the disks 1 and 2 rotate, and to tilt (tilt) between the disks 1 and 2. The input disk 1 and the output disk 2 and the power roller 9 sandwiched between the input disk 1 and the power roller 9 constitute a variator Va that performs substantial speed change and substantially sets the speed ratio. The example shown in FIG. Then, two variators Va are provided.

  Each power roller 9 is rotatably held by each trunnion 10, and the lower trunnion shaft 12 in each trunnion 10 in FIG. 2 is connected to an actuator. The actuator is configured to move the trunnion 10 in the vertical direction in FIG. 2 by a fluid pressure cylinder, a fluid pressure motor, a link mechanism, and the like. In the example shown in the figure, a hydraulic cylinder 17 is employed. .

  The mechanism for shifting the power roller 9 from the neutral position to the upshift side or the downshift side will be described. The mechanism is configured to operate an actuator such as the hydraulic cylinder 17. In the example shown in the figure, it is constituted by a solenoid valve. FIG. 2 shows an example using two control valves 19H and 19L. One control valve 19H moves the power roller 9 to the upshift side together with the trunnion 10, and the other control valve 19L is the trunnion 10 In addition, the power roller 9 is configured to move to the downshift side. Such a switching operation is performed by applying a control signal from the electronic control unit ECU to the solenoids 20H and 20L provided in the respective control valves 19H and 19L.

  The source pressure of each control valve 19H, 19L is a line pressure PL, which is a hydraulic pressure obtained by regulating the hydraulic pressure generated by the oil pump 21 by the valve body 22. Accordingly, the valve body 22 includes a pressure regulating valve that regulates pressure according to torque input to the toroidal type continuously variable transmission, another pressure regulating valve that regulates the drain hydraulic pressure of the pressure regulating valve to converter hydraulic pressure and lubricating hydraulic pressure, It includes a switching valve for switching the rotation, a pressing force control valve for controlling a roller pressing force for sandwiching the power roller 9 and the like. The valve body 22 is configured as a single unit by incorporating the valves and the oil passage inside a single casing.

  The configuration of the hydraulic device that controls the hydraulic pressure Pd for setting the line pressure PL and the roller pressing force will be described below. FIG. 1 is a hydraulic circuit diagram schematically showing a part of the hydraulic control device according to the present invention. A primary regulator valve 23 is provided that regulates the hydraulic pressure generated by the oil pump 21 to the line pressure PL that is the original pressure of the entire apparatus. The primary regulator valve 23 is the same as that provided as a valve for regulating the line pressure in a hydraulic control device in an automatic transmission for a vehicle, and is configured by a spool valve to feed back an output pressure. The pressure is applied to one end portion of the spool 24 as a pressure, and the signal pressure and the spring force are applied to the opposite side of the spool 24, and the load is sandwiched between the loads so as to balance and adjust the pressure. ing. The oil pump 21 is configured to be driven by an engine that is a power source of the vehicle or a motor (not shown) provided separately from the engine.

  More specifically, a land 25 is formed in the central portion of the spool 24 in the axial direction, and a line pressure port 26 and an output port 27 that are communicated and blocked with each other by the land 25 are formed. The line pressure port 26 communicates with the oil pump 21 via a line pressure oil passage 28. Further, the output port 27 is configured to supply drain oil generated by adjusting the line pressure PL to a valve (not shown) that performs lubrication and control of a torque converter (not shown).

  A spring 29 is disposed on one end side (the upper side in FIG. 1) of the land 25, and the spool 24 is pressed downward by the spring 29 in FIG. 1. In addition, a signal pressure port 30 that opens at a position where the spring 29 is disposed is formed, and a signal pressure is applied thereto. Further, another land 31 is formed on the opposite side (lower side in FIG. 1) across the output port 27 with respect to the land 25, and a feedback port 32 opening on the end face side of the land 31 is formed. Yes. The feedback port 32 communicates with the line pressure oil passage 28 via the orifice 33. The primary regulator valve 23 corresponds to the first pressure regulating valve in the present invention.

  A line pressure electromagnetic valve 34 for generating a signal pressure for the primary regulator valve 23 is provided. The line pressure electromagnetic valve 34 corresponds to the first electromagnetic valve in the present invention, and is configured to be electrically controlled to output a predetermined signal pressure. Specifically, a linear solenoid valve that outputs a hydraulic pressure corresponding to a current value as a signal pressure or a duty solenoid valve that outputs a hydraulic pressure corresponding to a duty ratio that is an ON / OFF ratio as a signal pressure is provided. In the example shown, a linear solenoid valve is used as the line pressure solenoid valve 34. Therefore, when the output pressure of the line pressure solenoid valve 34 is increased, the pressure regulation level in the primary regulator valve 23 is increased and the line pressure PL is increased. Conversely, when the output pressure of the line pressure solenoid valve 34 is decreased, the primary regulator valve The pressure regulation level at 23 is lowered and the line pressure PL is lowered.

  The hydraulic cylinder 6 that generates a roller pressing force for sandwiching the power roller 9 between the disks 1 and 2 corresponds to the hydraulic actuator in the present invention. The roller pressing control for supplying the roller pressing hydraulic pressure Pd to the hydraulic cylinder 6 A valve 35 is provided. This roller pressing control valve 35 is a valve that outputs the roller pressing hydraulic pressure Pd by adjusting the pressure according to the signal pressure using the line pressure PL as the original pressure, and corresponds to the second pressure adjusting valve in the present invention. is doing. In the example shown in FIG. 1, it is constituted by a spool valve, and an output pressure is applied to one end portion of the spool 36 as a feedback pressure, while a signal pressure and a spring force are applied to the opposite side of the spool 36 to sandwich the spool 36. It is configured to operate and adjust the pressure so that these loads are balanced.

  That is, two lands 37, 38 are formed in the spool 36, and an output port 39 that opens at a valley (valley) portion between these lands 37, 38 is formed. This output port 39 is connected to the hydraulic cylinder 6. It is communicated. A drain port 40 and an input port 41 are formed on both sides of the output port 39 (upper and lower sides in FIG. 1). The input port 41 is communicated with the line pressure oil passage 28 described above. When one land 37 closes the drain port 40, the other land 38 opens the input port 41 to communicate with the output port 39, and conversely, one land 37 opens the drain port 40. In the state where this is in communication with the output port 39, the other land 38 is configured to close the input port 41.

  A spring 42 is disposed on one land 37 side (the upper side in FIG. 1) of the spool 36, and the spool 36 is pressed downward by the spring 42 in FIG. 1. Further, a signal pressure port 43 that opens at a position where the spring 42 is disposed is formed, and a signal pressure is applied thereto. Further, a feedback port 44 that opens to the end face side of the other land 38 is formed. The feedback port 44 communicates with the output port 39 via the orifice 45.

  A roller pressing electromagnetic valve 46 for generating a signal pressure for the roller pressing control valve 35 is provided. The roller pressing electromagnetic valve 46 corresponds to the second electromagnetic valve in the present invention, and is configured to be electrically controlled to output a predetermined signal pressure. Specifically, a linear solenoid valve that outputs a hydraulic pressure corresponding to a current value as a signal pressure or a duty solenoid valve that outputs a hydraulic pressure corresponding to a duty ratio that is an ON / OFF ratio as a signal pressure is provided. In the example shown, a linear solenoid valve is used as the roller pressing electromagnetic valve 46. Therefore, the roller pressing electromagnetic valve 46 may be a valve having the same specifications and the same configuration as the line pressure electromagnetic valve 34 described above. When the output pressure of the roller pressing control valve 35 is increased, the pressure adjustment level in the roller pressing control valve 35 is increased, and the roller pressing hydraulic pressure Pd is increased. On the contrary, the output pressure of the roller pressing control valve 35 is increased. When the pressure is lowered, the pressure adjustment level in the roller pressing control valve 35 is lowered, and the roller pressing hydraulic pressure Pd is lowered.

  Furthermore, a line pressure modulator valve 47 is provided. The line pressure modulator valve 47 is a valve that stabilizes the line pressure PL and outputs the modulator pressure, and is similar to that used in the conventional hydraulic control device of an automatic transmission for a vehicle. The pressure is regulated by causing the elastic force and the feedback pressure of the output pressure to act against the spool. The modulator pressure is supplied as a source pressure to each of the electromagnetic valves 34 and 46 described above.

  The line pressure electromagnetic valve 34 and the signal pressure port 30 of the primary regulator valve 23 are communicated with each other by a first signal pressure oil passage 48, and the roller pressing electromagnetic valve 46 and the signal pressure port 43 of the roller pressing control valve 35 are The second signal pressure oil passage 49 communicates. The output pressure of the roller pressing control valve 35 (that is, the signal pressure to the roller pressing control valve 35) is not increased with respect to the output pressure of the line pressure electromagnetic valve 34 (that is, the signal pressure to the primary regulator valve 23). A hydraulic compensation circuit for compensation is provided. An example thereof is shown in FIG. 1, and in the example shown here, a hydraulic pressure compensation circuit is configured by an oil passage 51 that communicates each signal pressure oil passage 48, 49 via a check valve 50. Since the check valve 50 performs the above-described hydraulic pressure compensation, the line pressure signal pressure that is the output pressure of the line pressure solenoid valve 34 is higher than the roller pressure signal pressure that is the output pressure of the roller pressure control valve 35. If the signal pressure for line pressure is lower than the signal pressure for roller pressing, on the contrary, the signal pressure oil passages 48 and 49 are configured to communicate with each other.

  Here, the control of the line pressure PL and the roller pressing oil pressure Pd will be briefly described. The line pressure PL is set according to the torque input to the input shaft 4 from a power source such as an engine. The output torque of the engine as the power source can be estimated based on the throttle opening and intake air amount in the case of a gasoline engine, and the fuel injection amount in the case of a diesel engine. Therefore, the input shaft 4 is based on those estimated values or calculated values. Can be obtained. The electronic control unit ECU outputs a command signal corresponding to the torque thus obtained to the line pressure solenoid valve 34, and the output pressure corresponding to the command signal is sent from the line pressure solenoid valve 34 to the primary regulator valve 23 as a signal pressure. Supplied. The command signal and the output pressure have a relationship determined according to the specifications and characteristics of the line pressure solenoid valve 34. The pressure regulation level of the primary regulator valve 23 increases or decreases according to the input signal pressure, and therefore the line pressure PL is adjusted according to the signal pressure.

  The roller pressing hydraulic pressure Pd is set according to the torque to be transmitted by the variator Va. More specifically, this is obtained based on the torque input from the power source and the gear ratio, and the greater the input torque and the greater the gear ratio, the greater the torque to be transmitted. Set to The input torque can be obtained in advance as described above, and the gear ratio can be obtained by normal gear change control. Based on these data, the electronic control unit ECU outputs a command signal to the roller pressing electromagnetic valve 46. To do. Then, the roller pressing electromagnetic valve 46 outputs an output pressure based on the command signal according to the specifications or characteristics, and this is supplied to the roller pressing control valve 35 as a signal pressure. The pressure adjustment level of the roller pressing control valve 35 increases or decreases according to the input signal pressure, and as a result, the roller pressing hydraulic pressure Pd is set according to the signal pressure, that is, according to the torque to be transmitted.

  The roller pressing hydraulic pressure Pd thus set is adjusted to a pressure slightly lower than the line pressure PL. That is, the roller pressing control valve 35 performs pressure reduction control using the line pressure PL as a source pressure. This is because by reducing the line pressure PL as much as possible, the energy or fuel consumed for driving the oil pump 21 is reduced and the fuel efficiency is improved.

  Each of the solenoid valves 34 and 46 outputs a signal pressure corresponding to a command signal such as a current or a duty ratio. However, when the characteristic changes, the relationship between the command signal and the signal pressure that is the output pressure changes. Even if the same command signal is given, the output signal pressure may be different from the conventional pressure. Such a change may appear after a durability test of the solenoid valves 34 and 46, for example. The reason is not necessarily clear, but can be estimated as follows. That is, in the case of a linear solenoid valve, the thrust generated by the electromagnetic coil and the feedback pressure obtained by feeding back the output pressure are opposed to each other across the spool, and the spool opens and closes the port so as to balance these thrust and feedback pressure. Thus, an output pressure corresponding to the command signal is obtained. Therefore, the spool reciprocates in the axial direction so as to repeatedly open and close the input port, the output port or the drain port. On the other hand, since the spool is accommodated in the bore formed in the valve body so as to maintain a certain degree of liquid tightness, a sliding resistance is generated between the spool and the bore. After starting to use the solenoid valve, its sliding resistance may decrease or increase due to the occurrence of oil film or galling, etc., which appears as a change in characteristics, and the output pressure for the command signal changes. Conceivable.

  When the characteristics of the line pressure electromagnetic valve 34 change so that the output pressure becomes low, or when the characteristics of the roller pressing electromagnetic valve 46 change so that the output pressure becomes high, the respective output pressures gradually approximate. In an extreme case, the roller is set so that the output pressure of the roller pressing electromagnetic valve 46 (signal pressure for controlling the roller pressing force) is higher than the output pressure of the line pressure electromagnetic valve 34 (signal pressure for controlling the line pressure). The pressing solenoid valve 46 may operate. However, in the hydraulic control device according to the present invention, since the above-described hydraulic pressure compensation circuit is provided, it is avoided that the signal pressure for roller pressing becomes higher than the signal pressure for line pressure control. Specifically, when the output pressure of the roller pressing electromagnetic valve 46 becomes higher than the output pressure of the line pressure electromagnetic valve 34, the check valve 50 described above opens, and the signal pressure oil passage 49 on the roller pressing electromagnetic valve 46 side opens. Since the hydraulic pressure is released to the signal pressure oil passage 48 on the line pressure electromagnetic valve 34 side, the output pressure of the roller pressing electromagnetic valve 46 does not exceed the output pressure of the line pressure electromagnetic valve 34 even if it is maximized.

  In such a case, the signal pressure of the roller pressing control valve 35 is the same as the signal pressure for controlling the line pressure. Therefore, the roller pressing control valve 35 applies the line pressure as the input pressure to the roller having the same pressure. The pressure is adjusted to the pressing hydraulic pressure Pd and output. In this case, the spool 37 is in a so-called floating state and reciprocates in the axial direction according to a slight change in line pressure, and is not fixed to one end side in the axial direction.

  Accordingly, when control for increasing the line pressure or decreasing the roller pressing hydraulic pressure Pd is started from this state, the spool 37 is more actively reciprocated so as to perform the original pressure reduction control with the roller pressing hydraulic pressure Pd. However, since the spool 37 has reciprocated as described above even before that, the stroke of the spool 37 may overshoot in the transient state where the original pressure reduction control is started. Thus, hunting of the roller pressing hydraulic pressure Pd, which is the output pressure, does not occur. That is, according to the hydraulic control apparatus according to the present invention, the roller pressing hydraulic pressure Pd can be stably controlled even if the characteristics of the line pressure electromagnetic valve 34 and the roller pressing electromagnetic valve 46 change.

  The present invention is not limited to the specific example described above, and the hydraulic pressure compensation circuit according to the present invention is provided with an appropriate differential pressure valve and pressure regulating valve in addition to the hydraulic circuit provided with the check valve, and the second signal pressure oil. The road hydraulic pressure may be configured not to be higher than the hydraulic pressure of the first signal pressure oil path. In addition, the pressure regulating valve in the present invention is not limited to the spool type described above, and the pressure regulating level changes according to the input signal pressure, and the hydraulic pressure corresponding to the pressure regulating level is output. There may be.

1 is a partial hydraulic circuit diagram showing a part of a hydraulic control device according to the present invention. It is a figure for demonstrating the basic composition of the toroidal type continuously variable transmission made into object by this invention, Comprising: It is typical sectional drawing which follows a rotation center axis line.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Input disc, 2 ... Output disc, 4 ... Input shaft, 6 ... Hydraulic cylinder, 9 ... Power roller, 10 ... Trunnion, Va ... Variator, ECU ... Electronic control unit, 21 ... Oil pump, 23 ... Primary regulator valve, 28 ... Line pressure oil passage, 34 ... Line pressure solenoid valve, 35 ... Roller pressure control valve, 46 ... Roller pressure solenoid valve, 48 ... First signal pressure oil passage, 49 ... Second signal pressure oil passage, 50 ... Check valve, 51 ... Oil passage.

Claims (4)

The hydraulic pressure generated by the oil pump is regulated to a line pressure by a first pressure regulating valve that uses the output pressure of the first electromagnetic valve that is electrically controlled as a signal pressure, and the line pressure is electrically controlled. In a transmission hydraulic control device configured to be pressure-reduced by a second pressure regulating valve that uses an output pressure of a second electromagnetic valve as a signal pressure and to supply the pressure to a predetermined hydraulic actuator,
A first signal pressure oil passage for applying the signal pressure from the first solenoid valve to the first pressure regulating valve;
A second signal pressure oil passage for applying the signal pressure from the second solenoid valve to the second pressure regulating valve;
A transmission hydraulic pressure control device comprising: a hydraulic pressure compensation circuit that compensates so that a hydraulic pressure in the first signal pressure oil path is equal to or higher than a hydraulic pressure in the second signal pressure oil path.   The oil pressure compensation circuit is closed when the oil pressure in the first signal pressure oil path is higher than the oil pressure in the second signal pressure oil path, and the oil pressure in the first signal pressure oil path is the second oil pressure. An oil path is provided that connects the first signal pressure oil path and the second signal pressure oil path via a check valve that opens when the pressure in the signal pressure oil path is lower than the hydraulic pressure. Item 2. The transmission hydraulic control device according to Item 1.   The hydraulic control apparatus for a transmission according to claim 1 or 2, wherein the first electromagnetic valve and the second electromagnetic valve are valves having the same specification and configuration.   4. The first pressure regulating valve and the second pressure regulating valve each include a spool valve that performs pressure regulation with the output pressure as a feedback pressure against the signal pressure with a spool interposed therebetween. A hydraulic control device for a transmission according to any one of the above.

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