JP4354378B2 - Hydraulic control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a hydraulic control device for a continuously variable transmission, and in particular, a contact radius between the belt and each pulley while sandwiching a belt wound around two pulleys by hydraulic pressure supplied to each pulley. This is suitable as a hydraulic control device for a continuously variable transmission that can adjust the gear ratio between two pulleys steplessly.

As a hydraulic control device for such a continuously variable transmission, for example, the line pressure is a source pressure, the hydraulic pressure to the pulley on the input side is controlled by the output hydraulic pressure of the first solenoid valve, and the hydraulic pressure to the pulley on the output side is 2 Controlled by the output hydraulic pressure of the solenoid valve, the high pressure side hydraulic pressure is selected by the regulator valve from among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, and the selected high pressure side hydraulic pressure is set to the signal pressure. There is one that regulates the line pressure with a line pressure regulating valve (for example, Patent Document 1). In other words, in this continuously variable transmission hydraulic control device, the line pressure increases linearly together with the selected high-pressure solenoid valve output hydraulic pressure. Incidentally, the selected high pressure side solenoid valve output hydraulic pressure and the hydraulic pressure to the pulley are linear, and when the selected high pressure side solenoid valve output hydraulic pressure is zero, the hydraulic pressure to the pulley is also zero. Further, the solenoid valve output hydraulic pressure increases in accordance with the magnitude of the input torque from the engine.
Japanese Patent Laid-Open No. 11-247981

  By the way, in the hydraulic control device for a continuously variable transmission, since the hydraulic pressure to the pulley is based on the line pressure as described above, the line pressure must be higher than the hydraulic pressure to the pulley. Even if the hydraulic pressure to the pulley is not required, the line pressure is the original pressure of all the hydraulic pressures, so it is higher than the hydraulic pressure that can secure the required lubrication flow rate or higher than the hydraulic pressure that can prevent the lockup clutch from dragging. There must be. In other words, even if the oil pressure to the pulley (∝ selected high-pressure side solenoid valve output oil pressure) is zero, the line pressure cannot be zero, in other words, the intercept of the line pressure with respect to the selected high-pressure side solenoid valve output oil pressure. Is not zero (atmospheric pressure).

However, if the value of the line pressure when the selected high pressure side solenoid valve output hydraulic pressure is zero is the minimum required line pressure, the conventional hydraulic control device for a continuously variable transmission has the selected high pressure side Since the solenoid valve output hydraulic pressure and the line pressure are linear, there is virtually no need to increase the line pressure in a region where the pulley hydraulic pressure does not exceed the minimum required line pressure, but the line pressure also increases in that region. There is a problem of being done.
The present invention has been made paying attention to the above-described problems, and in the region where the selected high-pressure side solenoid valve output hydraulic pressure is less than a predetermined value, it is possible to suppress an increase in line pressure. It is an object of the present invention to provide a hydraulic control device for a step transmission.

In order to solve the above-described problem, in the hydraulic control device for a continuously variable transmission according to the present invention, while the belt wound around two pulleys is clamped by the hydraulic pressure supplied to each pulley, the belt, each pulley, A hydraulic control device for a continuously variable transmission capable of continuously adjusting a gear ratio between two pulleys by changing a contact radius of the first pulley, wherein a hydraulic pressure to one of the two pulleys is controlled. One solenoid valve, a second solenoid valve that controls the hydraulic pressure to one of the two pulleys, and the output hydraulic pressure of the first solenoid valve and the second solenoid valve is proportional to the high-pressure side solenoid valve output hydraulic pressure La was a high-pressure side solenoid valve output pressure selecting means for outputting a hydraulic pressure to the hydraulic circuit in accordance with the hydraulic pressure outputted from the high-pressure side solenoid valve output pressure selecting means it is higher In the hydraulic control device for a continuously variable transmission having a line pressure control means for controlling so that down pressure is high, the high pressure side solenoid valve output pressure from the high pressure side solenoid valves output hydraulic pressure selection means is less than a predetermined value region Then, line pressure holding means for holding the line pressure by the line pressure control means at a predetermined constant hydraulic pressure is provided.

In the hydraulic control device for a continuously variable transmission according to the present invention, the contact radius between the belt and each pulley is changed while the belt wound around the two pulleys is clamped by the hydraulic pressure supplied to each pulley. A continuously variable transmission hydraulic control device capable of continuously adjusting a gear ratio between the two pulleys, the first solenoid valve for controlling the hydraulic pressure to one of the two pulleys; A second solenoid valve that controls the hydraulic pressure to one of the two pulleys, and a high pressure that outputs a hydraulic pressure proportional to the high-pressure solenoid valve output hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve Side solenoid valve output hydraulic pressure selection means and the line pressure to the hydraulic circuit increases as the hydraulic pressure output from the high pressure side solenoid valve output hydraulic pressure selection means increases. In the hydraulic control device for a continuously variable transmission having a line pressure control means Gosuru, the ratio of change in width of the line pressure to the high pressure side solenoid valve output pressure variation width from the high-pressure side solenoid valves output hydraulic pressure selection means the gradient in represented, that pre SL high pressure side solenoid valve output fluid pressure towards the gradient at less than the predetermined value, provided line pressure change gradient changing means be smaller than the gradient at a predetermined value or more regions It is a feature.

Thus, according to the hydraulic control device for a continuously variable transmission of the present invention, the high pressure side hydraulic pressure proportional to the high pressure side hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve is output. in the region the high-pressure side hydraulic pressure less than a predetermined value which is, due to the configuration in which the line pressure holding means for holding the line pressure by the line pressure control means to a predetermined pressure, a high pressure side solenoid output pressure is less than a predetermined value region, the line The pressure is maintained at a predetermined constant hydraulic pressure, and the line pressure is controlled to increase as the output hydraulic pressure on the high pressure side increases in a region of a predetermined value or more. As a result, the line pressure can be reduced as compared with the conventional case, so that fuel efficiency can be improved.

Further , among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, a high-pressure side hydraulic pressure proportional to the high-pressure side hydraulic pressure is output , and the high-pressure side solenoid valve output in a region where the output high-pressure side hydraulic pressure is less than a predetermined value. a gradient represented by a ratio of variation of the line pressure for the hydraulic variation width, because of a structure to be smaller than the slope at a predetermined value or more areas, in the high pressure side solenoid valve output pressure is less than a predetermined value region, a high-pressure side The solenoid valve output hydraulic pressure is set to a low pressure state close to the line pressure at the minimum hydraulic pressure, and the line pressure is controlled to increase as the output hydraulic pressure on the high pressure side increases in a region of a predetermined value or more. As a result, it is possible to suppress excessive setting of the line pressure as compared with the conventional case, so that fuel efficiency can be improved.

Next, a first embodiment of a hydraulic control device for a continuously variable transmission according to the present invention will be described with reference to the drawings.
FIG. 1 is an excerpt of a portion for supplying hydraulic pressure to a primary (input side) pulley and a secondary (output side) pulley in a hydraulic control device for a continuously variable transmission according to the present embodiment. The configuration of the belt-type continuously variable transmission itself is well known including the above-mentioned Patent Document 1, and thus the description thereof is omitted. In addition, the x mark in the figure is drain.

In this hydraulic control device, the hydraulic pressure of the hydraulic oil in the reservoir 2 pressurized by the pump 1 is regulated by the line pressure regulating valve 3 to obtain the line pressure P _L which becomes the source pressure of all the hydraulic circuits. The pressure P _L is reduced by the pilot valve 4 to output a pilot pressure P _PLT which is a constant hydraulic pressure. The line pressure regulating valve 3 is a spool type regulating valve that _uses an output hydraulic pressure from a line pressure control device 14 described later, that is, a line control pressure P _LCTL as a signal pressure, and the line control pressure P _LCTL is zero. In this case, a predetermined line pressure P _L (= required minimum line pressure P _LMIN ) is output.

Using this pilot pressure P _PLT as a _source pressure, a primary pulley solenoid pressure P _PPSOL is created by the primary pulley (first) solenoid valve 5, and this primary pulley solenoid pressure P _PPSOL is used as a signal pressure, and the line pressure P _L is used as the _source pressure. The primary pulley control valve 6 creates a primary pulley pressure _PPP and supplies it to the primary pulley cylinder 8 of the primary pulley 7. On the other hand, using the pilot pressure P _PLT as a _source pressure, a secondary pulley solenoid pressure P _SPSOL is created by the secondary pulley (second) solenoid valve 9, and the secondary pulley solenoid pressure P _SPSOL is _used as a signal pressure, and the line pressure P _L is as the source pressure, and creates a secondary pulley pressure P _SP on the secondary pulley control valve 10, and supplies it to the secondary pulley cylinder 12 of the secondary pulley 11.

On the other hand, the secondary pulley solenoid pressure P _SPSOL that is created by the primary pulley solenoid pressure P _PPSOL and secondary pulley solenoid valve 9 that is created by the primary pulley solenoid valve 5 is supplied as a signal pressure to the regulator valve 13. In the regulator valve 13, the output pressure proportional to the high-pressure side solenoid pressure of either the primary pulley solenoid pressure P _{PPSOL or the} secondary pulley solenoid pressure P _SPSOL is obtained using the line pressure P _L as a _source pressure. Output as output hydraulic pressure P _HiSOL . That is, the regulator valve 13 corresponds to the high pressure side solenoid valve output hydraulic pressure selection means of the present invention.

A line control pressure P _LCTL for controlling the line pressure P _L by the line pressure regulating valve 3 is _lined from the high pressure side solenoid valve output hydraulic pressure P _HiSOL and the pilot pressure P _PLT selected and output by the regulator valve 13. Created by the pressure control device 14. In other embodiments described below, the pilot pressure P _PLT may not be required, or the line pressure control device 14 may be configured integrally with the line pressure regulating valve 3. In such a case, the hydraulic circuit of FIG.

FIG. 2 shows details of the line pressure control device 14 of the first embodiment. The line pressure control device 14 of the present embodiment is configured by a spool type pressure reducing valve in which the spool 15 has a pressure receiving area difference. The line pressure control device 14 composed of this spool type pressure reducing valve uses the pilot pressure P _PLT as an input hydraulic pressure, the high pressure side solenoid valve output hydraulic pressure P _HiSOL acts on the side where the pressure receiving area of the spool 15 is large, and the pressure received by the spool 15. The own output hydraulic pressure, that is, the line control pressure P _LCTL acts on the smaller area side, and the pilot pressure (individual constant hydraulic pressure) P _PLT also acts on the step portion 16 of the pressure receiving area of the spool 15.

In this line pressure control device 14, until the pilot pressure P _PLT acting on the step portion 16 of the spool 15 _{exceeds the} high pressure side solenoid valve output hydraulic pressure P _HiSOL , that is, the area of the end face of the spool 15 having a large pressure receiving area and the high pressure side solenoid. The output hydraulic pressure, that is, the line control pressure P _LCTL is zero until the force consisting of the product value of the valve output hydraulic pressure P _HiSOL becomes larger than the force consisting of the product value of the area of the step portion 16 and the pilot pressure P _PLT . After the high pressure side solenoid valve output hydraulic pressure P _HiSOL wins over the pilot pressure P _PLT acting on the step portion 16 of the spool 15, that is, the area of the end face of the spool 15 having a large pressure receiving area and the high pressure side solenoid valve output hydraulic pressure P _HiSOL after a force consisting of the product value is larger than a force consisting of a product value between the area and the pilot pressure P _PLT of the step portion 16 is increased line control pressure P _LCTL with increasing pressure side solenoid valve output pressure P _HiSOL also linear To do.

FIG. 3 shows the relationship between the high pressure side solenoid valve output hydraulic pressure P _HiSOL and the line control pressure P _LCTL . FIG. 4 also shows the line pressure P _L achieved in the present embodiment and the high pressure side pulley pressure achieved by the high pressure side solenoid valve output hydraulic pressure P _HiSOL among the primary pulley pressure P _PP and the secondary pulley pressure P _SP. The relationship with P _PHi is shown. As described above, even if the line control pressure P _LCTL is zero, the line pressure regulating valve 3 outputs the necessary minimum line pressure P _LMIN . After the line control pressure P _LCTL rises, the line pressure P _L proportional to the line control pressure P _LCTL is output. As described above, the line pressure P _L is also the original pressure of the high-pressure side pulley pressure P _PHi , so that, for example, as shown in the _circle in FIG. 4, an error in the high-pressure side pulley pressure P _{PHi and} an error in the line pressure P _L itself. including, at all times, set the line pressure P _L as a pressure higher than the high-pressure side pulley pressure P _PHi, the intersecting curves between the line pressure P _L to the required minimum line pressure P _LMIN the target value of the line pressure P _L The line control pressure P _LCTL , that is, the area of the end face of the spool 15 having a large pressure receiving area and the area of the stepped portion 16 constituting the pressure receiving area difference are set so that the target line pressure P _L is achieved.

As described above, the necessary minimum line pressure P _LMIN is a line pressure necessary for ensuring a necessary lubricating flow rate and preventing dragging of the lockup clutch, for example. That is, it can be said to be the original pressure of the hydraulic circuit itself that must be ensured regardless of the presence or absence of signal pressure to the line pressure regulating valve 3. Conventionally, for example, there is no line pressure control valve 14 of FIG. 1, since the high-pressure side solenoid valve output pressure P _HiSOL was supplied as a signal pressure line directly pressure regulating valve 3, the line pressure P _L, for example 5 As shown by a solid line, the line rises directly from the required minimum line pressure _PLMIN . When this conventional line pressure P _L in FIG. 4 shown by the two-dot chain line, the line pressure P _L of the present embodiment, in particular high-pressure side solenoid valve output pressure P _HiSOL is less than the predetermined value regions, i.e. small input torque state It turns out that it was set too much. According to the hydraulic control device for a continuously variable transmission according to the present embodiment, the line pressure in the small input torque state is not set excessively, leading to an improvement in fuel consumption .

Further, as a means for holding the line pressure P _L at a predetermined hydraulic pressure (necessary minimum line pressure P _LMIN ) in a region where the high pressure side solenoid valve output hydraulic pressure P _HiSOL is less than a predetermined value, a spool type pressure reducing valve having a pressure receiving area difference in the spool 15. The pilot pressure _PPLT , which is a constant hydraulic pressure, is used as the input hydraulic pressure, and the high pressure side solenoid valve output hydraulic pressure _PHISOL acts on the side where the pressure receiving area of the spool 15 is large, and the pressure _received by the spool 15 is Since its output hydraulic pressure, that is, the line control pressure P _LCTL acts on the smaller area side, and the pilot pressure P _PLT also acts on the stepped portion 16 of the pressure receiving area of the spool 15, the structure is simple and practical use is possible. Easy .

Next, a second embodiment of the hydraulic control device for a continuously variable transmission according to the present invention will be described with reference to FIG. The configuration of the hydraulic circuit of the present embodiment is the same as that of FIG. 1 of the first embodiment. The line pressure control device 14 of the present embodiment is configured by a spool type pressure reducing valve. In the line pressure control device 14 constituted by this spool type pressure reducing valve, the pilot pressure P _PLT is set as an input hydraulic pressure, the high pressure side solenoid valve output hydraulic pressure P _HiSOL acts on one end surface of the spool 17 and the other end of the spool 17 is _operated. The output oil pressure, that is, the line control pressure P _LCTL acts on the end face of the, and a spring 18 (elastic body) is provided on the end face side on which the line control pressure P _LCTL acts.

In this line pressure control device 14, until the high pressure side solenoid valve output hydraulic pressure P _HiSOL wins _against the elasticity of the spring 18 provided on the other end surface of the spool 17, that is, the area of the end surface of the spool 17 and the high pressure side solenoid valve output hydraulic pressure. until a force consisting of the product value of the P _HiSOL is greater than the force consisting of the product value of the displacement and the elastic coefficient of the spring 18, the output hydraulic pressure, i.e. the line control pressure P _LCTL is zero. After the high pressure side solenoid valve output hydraulic pressure P _HiSOL wins the elasticity of the spring 18 provided on the other end surface of the spool 17, that is, from the product value of the end surface area of the spool 17 and the high pressure side solenoid valve output hydraulic pressure P _HiSOL. after comprised force is greater than the force consisting of the product value of the displacement and the elastic coefficient of the spring 18 also increases linearly line control pressure P _LCTL with increasing pressure side solenoid valve output pressure P _HiSOL.

The output characteristic of the line control pressure P _{LCTL with} respect to the high-pressure side solenoid valve output hydraulic pressure P _HiSOL is the same as that in FIG. 3 of the first embodiment. Therefore, the line pressure P _L and the primary pulley pressure P in the present embodiment are the same. relationship between the high-pressure side pulley pressure _{P PHi} achieved by a high-pressure side solenoid valve output pressure _{P HiSOL} of _PP and secondary pulley pressure _{P SP} is shown in FIG. Accordingly, in this embodiment as well, as in the first embodiment, the line pressure is not excessively set in a region where the high-pressure side solenoid valve output hydraulic pressure P _HiSOL is less than a predetermined value, for example, in a small input torque state. This leads to improved fuel economy .

Further, the line pressure control device constituted by a spool type pressure reducing valve as means for holding the line pressure P _L at a predetermined hydraulic pressure (required minimum line pressure P _LMIN ) when the high pressure side solenoid valve output hydraulic pressure P _HiSOL is less than a predetermined value. 14, the pilot pressure _PPLT , which is a constant hydraulic pressure, is used as the input hydraulic pressure, the high pressure side solenoid valve output hydraulic pressure P _HiSOL acts on one end face of the spool 17, and the output hydraulic pressure of the spool 17, ie, the line since the control pressure P _LCTL is act and the line control pressure P _LCTL is configured by providing a spring 18 (elastic member) to the end face side to act, it is easy to structure is simple practical, and the larger oil pressure variation instead, by performing switching using the elastic force of the spring 18, suppressing the output variation of the line control pressure P _LCTL Bets since can improves the control accuracy of the line pressure P _L as the original pressure, further improving fuel economy.

Next, a third embodiment of the hydraulic control device for continuously variable transmission according to the present invention will be described with reference to FIG. The configuration of the hydraulic circuit of the present embodiment is the same as that of FIG. 1 of the first embodiment, but the line pressure control device 14 of the present embodiment does not require the pilot pressure P _PLT , so the pilot valve 4 An oil passage from is not required. The line pressure control device 14 of the present embodiment is configured by a spool type switching valve. In the line pressure control device 14 constituted by this spool type switching valve, the high pressure side solenoid valve output hydraulic pressure P _HiSOL is _set as the input hydraulic pressure, and the high pressure side solenoid valve output hydraulic pressure P _HiSOL acts on one end surface of the spool 19 and A spring 20 is provided on the other end surface of the spool 17.

In this line pressure control device 14, until the high pressure side solenoid valve output hydraulic pressure P _HiSOL wins _against the elasticity of the spring 20 provided on the other end surface of the spool 17, that is, the area of the end surface of the spool 19 and the high pressure side solenoid valve output hydraulic pressure. until a force consisting of the product value of the P _HiSOL is greater than the force consisting of the product value of the displacement and the elastic coefficient of the spring 20, the output hydraulic pressure, i.e. the line control pressure P _LCTL is zero. After the high pressure side solenoid valve output hydraulic pressure P _HiSOL wins against the elasticity of the spring 20 provided on the other end surface of the spool 17, that is, from the product value of the end surface area of the spool 19 and the high pressure side solenoid valve output hydraulic pressure P _HiSOL. after comprised force is greater than the force consisting of the product value of the displacement and the elastic coefficient of the spring 20 also increases linearly line control pressure P _LCTL with increasing pressure side solenoid valve output pressure P _HiSOL.

The output characteristic of the line control pressure P _{LCTL with} respect to the high-pressure side solenoid valve output hydraulic pressure P _HiSOL is the same as that in FIG. 3 of the first embodiment. Therefore, the line pressure P _L and the primary pulley pressure P in the present embodiment are the same. relationship between the high-pressure side pulley pressure _{P PHi} achieved by a high-pressure side solenoid valve output pressure _{P HiSOL} of _PP and secondary pulley pressure _{P SP} is shown in FIG. Accordingly, in this embodiment as well, as in the first embodiment, the line pressure is not excessively set in a region where the high-pressure side solenoid valve output hydraulic pressure P _HiSOL is less than a predetermined value, for example, in a small input torque state. This leads to improved fuel economy .

As a means for holding the high-pressure side solenoid valve output pressure P _HiSOL is the line pressure P _L in the region less than a predetermined value to a predetermined hydraulic pressure (the minimum required line pressure P _LMIN), configured line pressure control device in the spool type switching valve with 14, the high-pressure side solenoid valve output pressure _{P HiSOL} as input hydraulic, spring 20 (elastic member the other end face of the high-pressure side solenoid valve output pressure _{P HiSOL} on one end face of the spool 19 acts and the spool 1 9 ), The structure is simple, practical application is easy, and there is no pressure reducing function, which is advantageous for hydraulic vibration .

Next, a fourth embodiment of the hydraulic control device for a continuously variable transmission according to the present invention will be described with reference to FIG. The configuration of the hydraulic circuit of the present embodiment is the same as that of FIG. 1 of the first embodiment. The line pressure control device 14 according to this embodiment includes a spool type pressure reducing valve 21 and a shuttle ball 22. Among these, in the spool type pressure reducing valve 21, the pilot pressure P _PLT , which is a constant hydraulic pressure, is used as an input hydraulic pressure, its own output hydraulic pressure P _REG acts on one end face of the spool 23, and a spring 24 is applied to the other end face of the spool 23. (Elastic body) is provided and configured. The shuttle ball 22 is _supplied with the constant output hydraulic pressure P _REG of the spool type pressure reducing valve 21 and the high-pressure solenoid valve output hydraulic pressure P _HiSOL , and the output hydraulic pressure of the shuttle ball 22 is the signal of the line pressure regulating valve 3. Pressure, that is, the line control pressure P _LCTL is output.

In this line pressure control device 14, the pilot pressure P _PLT is reduced to the constant output oil pressure P _REG by the spool type pressure reducing valve 21, so that the high pressure side solenoid valve output oil pressure P _HiSOL is less than the constant output oil pressure P _REG . Sometimes, the shuttle ball 22 seals the oil path on the high pressure side solenoid valve output hydraulic pressure P _HiSOL side, and _connects the oil path on the constant output hydraulic pressure P _REG side and the oil path on the line pressure regulating valve 3 side to make a constant Output hydraulic pressure P _REG is output as line control pressure. On the other hand, when the high pressure side solenoid valve output hydraulic pressure P _HiSOL becomes _equal to or higher than the constant output pressure P _REG from the spool type pressure reducing valve 21, the shuttle ball 22 seals the oil path on the constant output hydraulic pressure P _REG side and the high pressure side solenoid. the oil passage in the oil passage and the line pressure adjusting valve 3 side of the valve output pressure P _HiSOL communicated, high-pressure-side solenoid valve output pressure P _HiSOL is output as the line control pressure P _LCTL. Thereafter, the line control pressure P _LCTL also increases linearly as the high-pressure side solenoid valve output hydraulic pressure P _HiSOL increases.

The output characteristic of the line control pressure P _{LCTL with} respect to the high-pressure side solenoid valve output hydraulic pressure P _{HiSOL is such that} the output characteristic of FIG. 3 of the first embodiment drifts in the positive direction. and P _L, the relationship between the high-pressure side pulley pressure _{P PHi} achieved by a high-pressure side solenoid valve output pressure _{P HiSOL} of primary pulley pressure _{P PP} and secondary pulley pressure _{P SP} is shown in FIG. 11. Accordingly, in this embodiment as well, as in the first embodiment, the line pressure is not excessively set in a region where the high-pressure side solenoid valve output hydraulic pressure P _HiSOL is less than a predetermined value, for example, in a small input torque state. This leads to improved fuel economy .

The spool pressure reducing valve 21 and the shuttle ball 22 are configured as means for holding the line pressure P _L at a predetermined hydraulic pressure (required minimum line pressure P _LMIN ) when the high-pressure side solenoid valve output hydraulic pressure P _HiSOL is less than a predetermined value. The spool pressure reducing valve 21 uses the pilot pressure _PPLT , which is a constant oil pressure, as an input oil pressure, and the constant output oil pressure P _{REG of} its own acts on one end surface of the spool 23 so that the other of the spool 23 Since the spring 24 is provided on the end face of the cylinder and the constant output hydraulic pressure P _REG of the spool type pressure reducing valve 21 and the high pressure side solenoid valve output hydraulic pressure P _HiSOL act on the shuttle ball 22, the structure is simple and easy to put into practical use. And the pilot pressure is not used as the operating pressure of the pressure reducing valve. Prevents variation variations in the line control pressure P _LCTL by the pressure, it is possible to improve the control accuracy of the line pressure P _L as the original pressure. Further, since the constant output hydraulic pressure P _REG of the spool type pressure reducing valve 21 becomes the pilot pressure P _PLT on the extension side of the spring 24, for example, when the engine is turned off when the engine is turned off, the valve is cold when the engine is turned off. sticks even when (reduction by clearance) occurs, the reliability of the transmission is improved by securing the maximum value of the line pressure P _L.

Next, a fifth embodiment of the hydraulic control device for a continuously variable transmission according to the present invention will be described with reference to FIG. The configuration of the hydraulic circuit of the present embodiment is the same as that of FIG. 1 of the first embodiment, but the line pressure control device 14 of the present embodiment does not require the pilot pressure P _PLT , so the pilot valve 4 An oil passage from is not required. The line pressure control device 14 (line pressure change gradient changing means) of the present embodiment includes a plug 25 that moves the spool 3a of the line pressure regulating valve 3 using the high-pressure side solenoid valve output hydraulic pressure P _HiSOL as a signal pressure, A spring 26 (first elastic body) interposed between the spool 3a of the line pressure regulating valve 3 and the fixed wall, and between the plug 25 and the spool 3a of the line pressure regulating valve 3 are interposed. And a mounted spring 27 (second elastic body).

In this line pressure control device 14, in a region where the high pressure side solenoid valve output hydraulic pressure P _HiSOL is small, that is, in a small input torque state, the plug 25 and the spool 3 a of the line pressure regulating valve 3 are separated from each other. As the output hydraulic pressure P _HiSOL increases, the spring 27 between the spool 3a and the plug 25 contracts, and the line pressure P _L slightly increases as the load increases accordingly. After the high pressure side solenoid valve output hydraulic pressure P _HiSOL is further increased and the plug 25 _comes into _contact with the spool 3a of the line pressure regulating valve 3, the line pressure P _L is linear as the high pressure side solenoid valve output hydraulic pressure P _HiSOL increases. To increase. In other words, as shown in FIG. 13, the gradient represented by the ratio of the change width of the line pressure for the variation of the high-pressure side solenoid valve output pressure P _HiSOL, the selected high pressure side solenoid valve output pressure P _HiSOL is The gradient in the region below the predetermined value is set smaller than the gradient in the region above the predetermined value.

Therefore, according to the hydraulic control system of the continuously variable transmission of the present embodiment, in a region smaller than the predetermined value is the high pressure side solenoid valve output pressure P _HiSOL, high-pressure side solenoid valve output pressure P _HiSOL need minimum line be varied Since the low pressure state is close to the pressure P _LMIN , the excessive setting of the line pressure P _L is suppressed, leading to an improvement in fuel consumption .
Further, the high pressure side solenoid valve output pressure P _HiSOL is means for suppressing an increase in the line pressure P _L in the region of less than a predetermined value, as a signal pressure to the high pressure side solenoid valve output pressure P _HiSOL line pressure adjusting valve 3 spool 3a Therefore, it is easy to put into practical use with a simple structure because the spring 25 is interposed between the plug 25 that moves the valve 25 and the spool 3a of the line pressure regulating valve 3 .

1 is a hydraulic circuit diagram showing a first embodiment of a hydraulic control device for a continuously variable transmission according to the present invention. It is a detailed block diagram of the line pressure control apparatus of the hydraulic circuit of FIG. It is an output characteristic figure of the line control pressure by the line pressure control device of FIG. It is an output characteristic figure of line pressure by the line pressure control device of FIG. It is a conventional line pressure output characteristic diagram. It is a detailed block diagram of the line pressure control apparatus which shows 2nd Embodiment of the hydraulic control apparatus of the continuously variable transmission of this invention. It is an output characteristic figure of line pressure by the line pressure control device of FIG. It is a detailed block diagram of the line pressure control apparatus which shows 3rd Embodiment of the hydraulic control apparatus of the continuously variable transmission of this invention. It is an output characteristic figure of line pressure by the line pressure control device of FIG. It is a detailed block diagram of the line pressure control apparatus which shows 4th Embodiment of the hydraulic control apparatus of the continuously variable transmission of this invention. It is an output characteristic figure of line pressure by the line pressure control device of FIG. It is a detailed block diagram of the line pressure control apparatus which shows 5th Embodiment of the hydraulic control apparatus of the continuously variable transmission of this invention. It is an output characteristic figure of line pressure by the line pressure control device of FIG.

Explanation of symbols

1 is a pump 2 is a reservoir 3 is a line pressure regulating valve 4 is a pilot valve 5 is a primary pulley solenoid valve 6 is a primary pulley control valve 7 is a primary pulley 8 is a primary pulley cylinder 9 is a secondary pulley solenoid valve 10 is a secondary pulley control valve 11, secondary pulley 12, secondary pulley cylinder chamber 13, regulator valve 14, line pressure control devices 15, 17, 19, 23, spool 16, stepped portions 18, 20, 24, 26, 27, spring 21, spool type pressure reducing valve 22 is a shuttle ball 25 is a plug

Claims (5)

  While pinching the belt wound around two pulleys by the hydraulic pressure supplied to each pulley, the gear ratio between the two pulleys can be adjusted steplessly by changing the contact radius between the belt and each pulley A hydraulic control device for a continuously variable transmission, comprising: a first solenoid valve that controls a hydraulic pressure to one of the two pulleys; and a second solenoid valve that controls a hydraulic pressure to the other of the two pulleys. A solenoid valve, high pressure side solenoid valve output hydraulic pressure selection means for outputting a hydraulic pressure proportional to the high pressure side solenoid valve output hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, and the high pressure side solenoid valve output A continuously variable transmission comprising line pressure control means for controlling the line pressure to the hydraulic circuit to increase as the hydraulic pressure output from the hydraulic pressure selection means increases. In the hydraulic pressure control apparatus, in the region where the high pressure side solenoid valve output hydraulic pressure from the high pressure side solenoid valve output hydraulic pressure selection means is less than a predetermined value, the line pressure holding that holds the line pressure by the line pressure control means at a predetermined constant hydraulic pressure is maintained. The line pressure control means comprises a line pressure regulating valve that outputs a line pressure using the output hydraulic pressure of the line pressure holding means as a signal pressure, and the line pressure holding means has a pressure receiving area difference in the spool. The pilot pressure, which is composed of a certain spool-type pressure reducing valve and is a constant hydraulic pressure, is used as the input hydraulic pressure, and the high pressure side solenoid valve output hydraulic pressure acts on the side where the pressure receiving area of the spool is large, and the output of itself is generated on the side where the pressure receiving area of the spool is small A continuously variable transmission characterized by the fact that the pilot pressure acts on a step portion of the pressure receiving area of the spool. Hydraulic control apparatus.   While pinching the belt wound around two pulleys by the hydraulic pressure supplied to each pulley, the gear ratio between the two pulleys can be adjusted steplessly by changing the contact radius between the belt and each pulley A hydraulic control device for a continuously variable transmission, comprising: a first solenoid valve that controls a hydraulic pressure to one of the two pulleys; and a second solenoid valve that controls a hydraulic pressure to the other of the two pulleys. A solenoid valve, high pressure side solenoid valve output hydraulic pressure selection means for outputting a hydraulic pressure proportional to the high pressure side solenoid valve output hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, and the high pressure side solenoid valve output A continuously variable transmission comprising line pressure control means for controlling the line pressure to the hydraulic circuit to increase as the hydraulic pressure output from the hydraulic pressure selection means increases. In the hydraulic pressure control apparatus, in the region where the high pressure side solenoid valve output hydraulic pressure from the high pressure side solenoid valve output hydraulic pressure selection means is less than a predetermined value, the line pressure holding that holds the line pressure by the line pressure control means at a predetermined constant hydraulic pressure is maintained. The line pressure control means comprises a line pressure regulating valve that outputs a line pressure using the output hydraulic pressure of the line pressure holding means as a signal pressure, and the line pressure holding means comprises a spool type pressure reducing valve. The pilot pressure, which is a constant hydraulic pressure, is used as the input hydraulic pressure, the high-pressure side solenoid valve output hydraulic pressure acts on one of the spools, and the output hydraulic pressure of its own acts on the other of the spools. A hydraulic control device for a continuously variable transmission, characterized in that an elastic body is provided on the acting side.   While pinching the belt wound around two pulleys by the hydraulic pressure supplied to each pulley, the gear ratio between the two pulleys can be adjusted steplessly by changing the contact radius between the belt and each pulley A hydraulic control device for a continuously variable transmission, comprising: a first solenoid valve that controls a hydraulic pressure to one of the two pulleys; and a second solenoid valve that controls a hydraulic pressure to the other of the two pulleys. A solenoid valve, high pressure side solenoid valve output hydraulic pressure selection means for outputting a hydraulic pressure proportional to the high pressure side solenoid valve output hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, and the high pressure side solenoid valve output A continuously variable transmission comprising line pressure control means for controlling the line pressure to the hydraulic circuit to increase as the hydraulic pressure output from the hydraulic pressure selection means increases. In the hydraulic pressure control apparatus, in the region where the high pressure side solenoid valve output hydraulic pressure from the high pressure side solenoid valve output hydraulic pressure selection means is less than a predetermined value, the line pressure holding that holds the line pressure by the line pressure control means at a predetermined constant hydraulic pressure is maintained. The line pressure control means is constituted by a line pressure regulating valve that outputs a line pressure using the output hydraulic pressure of the line pressure holding means as a signal pressure, and the line pressure holding means is constituted by a spool type switching valve. And the high pressure side solenoid valve output hydraulic pressure is used as an input hydraulic pressure, the high pressure side solenoid valve output hydraulic pressure acts on one of the spools, and an elastic body is provided on either of the spools. Hydraulic control device for transmission.   While pinching the belt wound around two pulleys by the hydraulic pressure supplied to each pulley, the gear ratio between the two pulleys can be adjusted steplessly by changing the contact radius between the belt and each pulley A hydraulic control device for a continuously variable transmission, comprising: a first solenoid valve that controls a hydraulic pressure to one of the two pulleys; and a second solenoid valve that controls a hydraulic pressure to the other of the two pulleys. A solenoid valve, high pressure side solenoid valve output hydraulic pressure selection means for outputting a hydraulic pressure proportional to the high pressure side solenoid valve output hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, and the high pressure side solenoid valve output A continuously variable transmission comprising: a line pressure control means for controlling the line pressure to the hydraulic circuit to increase as the hydraulic pressure output from the hydraulic pressure selection means increases. In the hydraulic pressure control apparatus, in the region where the high pressure side solenoid valve output hydraulic pressure from the high pressure side solenoid valve output hydraulic pressure selection means is less than a predetermined value, the line pressure holding that holds the line pressure by the line pressure control means at a predetermined constant hydraulic pressure is maintained. The line pressure control means comprises a line pressure regulating valve that outputs a line pressure using the output hydraulic pressure of the line pressure holding means as a signal pressure, and the line pressure holding means is a pilot pressure that is a constant hydraulic pressure. A spool-type pressure reducing valve in which one of the spools has its own output hydraulic pressure and an elastic body is provided on either one of the spools, the output pressure of the spool-type pressure reducing valve, and the high-pressure side solenoid valve An output hydraulic pressure is input, and the higher one of the two hydraulic pressures is output as the signal pressure of the line pressure regulating valve. Hydraulic control device for a continuously variable transmission, characterized in that it is constituted by a Toruboru. While pinching the belt wound around two pulleys by the hydraulic pressure supplied to each pulley, the gear ratio between the two pulleys can be adjusted steplessly by changing the contact radius between the belt and each pulley A hydraulic control device for a continuously variable transmission, comprising: a first solenoid valve that controls a hydraulic pressure to one of the two pulleys; and a second solenoid valve that controls a hydraulic pressure to the other of the two pulleys. A solenoid valve, high pressure side solenoid valve output hydraulic pressure selection means for outputting a hydraulic pressure proportional to the high pressure side solenoid valve output hydraulic pressure among the output hydraulic pressures of the first solenoid valve and the second solenoid valve, and the high pressure side solenoid valve output A continuously variable transmission comprising line pressure control means for controlling the line pressure to the hydraulic circuit to increase as the hydraulic pressure output from the hydraulic pressure selection means increases. In the hydraulic pressure control apparatus, the high pressure side solenoid valve output hydraulic pressure has a gradient represented by a ratio of the change width of the line pressure to the change width of the high pressure side solenoid valve output hydraulic pressure from the high pressure side solenoid valve output hydraulic pressure selecting means. Line pressure change gradient changing means is provided for making the gradient less than a predetermined value smaller than the gradient in an area greater than or equal to a predetermined value , and the line pressure control means outputs a line pressure corresponding to the amount of movement of the spool. The line pressure adjusting valve includes a plug that moves a spool of the line pressure adjusting valve using the high pressure side solenoid valve output oil pressure as a signal pressure, and the line pressure adjusting valve. A first elastic body interposed between the spool and the fixed wall; and between the plug and the spool of the line pressure regulating valve. Hydraulic control device for a continuously variable transmission, characterized in that consists of a second elastic body that is so.

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