JP2009014162A - Hydraulic circuit for belt-type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic circuit for a belt-type continuously variable transmission, which attains compatibility between the rises of line pressure and clutch pressure when an engine is started. <P>SOLUTION: The hydraulic circuit for a belt-type continuously variable transmission comprises a line pressure regulating valve 40, a clutch pressure regulating valve 60 for generating a clutch pressure, a first clutch pressure oil passage 46 connecting the line pressure and clutch pressure regulating valves, a second clutch pressure oil passage 61 connecting the first clutch pressure oil passage and a frictional engagement means, a feedback oil passage 63 connecting the second clutch pressure oil passage and the clutch pressure regulating valve, a bypass oil passage 44 communicating the feedback oil passage and a line pressure oil passage with each other, and an orifice 64 provided for the feedback oil passage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic circuit of a belt type continuously variable transmission.

  Conventionally, in a hydraulic circuit of a belt-type continuously variable transmission, a line pressure control valve that generates an original pressure (line pressure) for adjusting a transmission ratio of a continuously variable transmission mechanism by adjusting a discharge pressure of an oil pump, and this line pressure Some have provided a clutch control valve that generates clutch pressure by using surplus oil drained from the control valve. This is because the required hydraulic pressure of the clutch is usually lower than the required hydraulic pressure of the continuously variable transmission mechanism, and if the line pressure acts on the clutch, the durability of the clutch is reduced, and therefore it is necessary to reduce the pressure from the viewpoint of clutch protection. .

As described above, in the configuration in which the line pressure is reduced and supplied to the clutch control valve, in a state where the pump discharge pressure does not rise sufficiently such as immediately after the engine is started, no excess pressure is generated until the line pressure reaches the target hydraulic pressure. The rising of the clutch pressure is also delayed. Therefore, a bypass oil passage that connects the line pressure oil passage that supplies the line pressure to the line pressure control valve and a clutch pressure oil passage that supplies the clutch pressure to the clutch control valve is provided, and the bypass oil passage is provided with an orifice. Such a configuration is disclosed in Patent Document 1.
JP 2004-124961 A

  In the overpressure state where the discharge pressure of the oil pump is excessively increased, if the line pressure is excessively increased without the control of the line pressure control valve in time, the clutch pressure is also excessively increased through the bypass oil passage. When the clutch pressure is excessively increased, the clutch engagement pressure is excessively engaged, and the durability of the clutch may be reduced.

  In addition, by providing a bypass oil passage connected to the clutch pressure oil passage, a part of the line pressure flows from the bypass oil passage to the clutch pressure oil passage, improving the rise of the clutch pressure, while the rise of the line pressure is delayed It becomes. Thus, when the bypass oil passage is provided, it is difficult to achieve both the rising of the clutch pressure and the rising of the line pressure.

  The present invention has been made paying attention to the above-described problems, and suppresses the increase of the clutch pressure even when the line pressure rises excessively, and achieves both the rise of the clutch pressure and the rise of the line pressure. It is an object of the present invention to provide a hydraulic circuit for a belt type continuously variable transmission that enables the above.

  According to a first aspect of the present invention, there is provided a belt-type continuously variable transmission mechanism including a pair of pulleys and a belt suspended between the pulleys, and an engagement state of a friction clutch to control the belt-type continuously variable transmission mechanism from the engine. A belt-type non-rotating mechanism comprising: a forward / reverse switching mechanism for switching the direction of rotation transmitted; and an oil pump for supplying the belt-type continuously variable transmission mechanism with a line pressure required for the pulley to clamp the belt. In the step transmission, a line pressure adjusting valve that supplies a line pressure obtained by adjusting the discharge pressure of the oil pump to the belt-type continuously variable transmission mechanism via a line pressure oil passage, and draining from the line pressure adjusting valve. Clutch pressure adjustment that adjusts the hydraulic pressure of excess oil to generate the clutch pressure necessary for the friction clutch to be engaged, and supplies the clutch pressure to the friction clutch via the clutch pressure oil passage And supplying a pilot pressure for controlling the clutch pressure adjusting valve so that the clutch pressure decreases when the clutch pressure rises above a target pressure when branched from the clutch pressure oil passage and connected to the clutch pressure adjusting valve. A feedback oil passage, a bypass oil passage connecting the feedback oil passage and the line pressure oil passage, and adding a line pressure to a pilot pressure, a branch portion of the feedback oil passage with the clutch pressure oil passage, Similarly, the hydraulic circuit of the belt type continuously variable transmission includes an orifice provided between the merging portion of the bypass oil passage.

  According to a second invention, in the first invention, the clutch pressure adjusting valve is positioned according to the pilot pressure, a supply port to which surplus oil from the line pressure adjusting valve is supplied, and the spool A discharge port that communicates with the supply port and discharges surplus oil, and the clutch pressure from the line pressure adjustment valve in an overpressure state in which the discharge pressure of the oil pump is excessively increased. When the hydraulic pressure to the regulating valve and the bypass hydraulic pressure of the bypass oil passage rise, the flow rate of excess oil flowing from the supply port to the discharge port increases as the pilot pressure to which the bypass hydraulic pressure is added is higher The spool moves to suppress the hydraulic pressure to the clutch pressure adjusting valve, and the increased pilot pressure acts on the clutch pressure from the feedback oil passage. The Rukoto suppressed by the orifice, a hydraulic circuit of a belt-type continuously variable transmission, characterized in that to suppress the increase of the clutch pressure.

  According to a third aspect of the present invention, in the first aspect of the present invention, a switching valve that can be controlled to open and close is provided in the bypass oil passage, and a control unit that controls the opening and closing of the switching valve. The hydraulic circuit of the belt-type continuously variable transmission is characterized in that the switching valve is closed and the bypass oil passage is closed until a lapse of time.

  In the first invention, when the clutch pressure rises above the target pressure, such as when the discharge pressure of the oil pump is in an overpressure state, the pilot pressure increased by adding the bypass hydraulic pressure from the bypass oil passage is Acting on the clutch pressure adjusting valve, the clutch pressure adjusting valve is controlled to reduce the clutch pressure. Further, by providing the orifice in the feedback oil passage, the bypass pressure does not directly act on the clutch pressure oil passage, and the clutch pressure is suppressed from being in an overpressure state. Furthermore, the amount of oil supplied from the feedback oil passage to the clutch pressure oil passage is adjusted by the orifice, so that both the rise of the line pressure and the rise of the clutch pressure can be achieved.

  In the second invention, when the discharge pressure of the oil pump is in an overpressure state, excess oil supplied to the clutch pressure adjusting valve is discharged from the supply port to the discharge port, so that an increase in the clutch pressure can be suppressed. it can.

  In the third aspect of the invention, a switching valve is provided in the bypass oil passage, and the switching valve is closed and the bypass oil passage is closed until a predetermined time elapses after the engine is started. The oil pressure from the oil pump is preferentially supplied to the cylinder chamber of the belt-type continuously variable transmission mechanism until the predetermined time elapses, and after the predetermined time has elapsed, the switching valve is opened and the line pressure is increased. The rising of the clutch pressure can be maintained by supplying the portion from the bypass oil passage to the feedback oil passage. Such control makes it possible to achieve both rising of the line pressure and the clutch pressure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of an automatic transmission provided with a belt type continuously variable transmission 3 (hereinafter referred to as CVT).

  In the figure, 1 is a torque converter to which power of an engine (not shown) is transmitted, 2 is a lock-up clutch, 3 is CVT, 4 is a primary rotation speed sensor of a primary pulley 30a of CVT 3, and 5 is a secondary rotation of a secondary pulley 30b. Number sensor, 6 is a hydraulic control valve unit, 8 is an oil pump driven by an engine, 9 is a CVT control unit, and 10 is a throttle opening sensor.

  An engine output shaft is connected to the torque converter 1 serving as a rotation transmission mechanism, and a lock-up clutch 2 that directly connects the engine and the CVT 3 is provided. The output side of the torque converter 1 is connected to the ring gear 21 of the forward / reverse switching mechanism 20. The forward / reverse switching mechanism 20 includes a planetary gear mechanism including a ring gear 21 connected to the engine output shaft 12, a pinion carrier 22, and a sun gear 23 connected to the transmission input shaft 13. The pinion carrier 22 is provided with a reverse brake 24 that fixes the pinion carrier 22 to the transmission case, and a forward clutch 25 that integrally connects the transmission input shaft 13 and the pinion carrier 22. With such a configuration, by controlling the engaged state of the forward clutch 25 and the reverse brake 24, the rotational direction of the engine output shaft 12 is controlled according to the control signal of the CVT control unit 9 and transmitted to the transmission input shaft 13. To do.

  A primary pulley 30a of the CVT 3 is provided at the end of the transmission input shaft 13. The CVT 3 includes the primary pulley 30a, the secondary pulley 30b, a belt 34 that transmits the rotational force of the primary pulley 30a to the secondary pulley 30b, and the like. The primary pulley 30 a has a fixed conical plate 31 that rotates integrally with the transmission input shaft 13, a V-shaped pulley groove that is disposed opposite to the fixed conical plate 31, and is shifted by hydraulic pressure that acts on the primary pulley cylinder chamber 33. The movable conical plate 32 is movable in the axial direction of the machine input shaft 13.

  The secondary pulley 30 b is provided on a driven shaft 38 that is disposed in parallel with the transmission input shaft 13. The secondary pulley 30 b has a fixed conical plate 35 that rotates integrally with the driven shaft 38, a V-shaped pulley groove that is disposed opposite to the fixed conical plate 35, and is driven by hydraulic pressure that acts on the secondary pulley cylinder chamber 37. The movable conical plate 36 is movable in the axial direction.

  A drive gear (not shown) is fixed to the driven shaft 38, and this drive gear drives a drive shaft that reaches the wheels via a pinion, a final gear, and a differential gear provided on the idler shaft.

  The rotational force input from the engine output shaft 12 to the CVT 3 as described above is transmitted to the CVT 3 via the torque converter 1 and the forward / reverse switching mechanism 20. The rotational force of the transmission input shaft 13 is transmitted to the differential device via the primary pulley 30a, belt 34, secondary pulley 30b, driven shaft 38, drive gear, idler gear, idler shaft, pinion, and final gear.

  During the power transmission as described above, by moving the movable conical plate 32 of the primary pulley 30a and the movable conical plate 36 of the secondary pulley 30b in the axial direction to change the contact position radius with the belt 34, the primary pulley 30a The rotation ratio between the secondary pulley 30b, that is, the gear ratio can be changed. Control for changing the width of the V-shaped pulley groove is performed by hydraulic control to the primary pulley cylinder chamber 33 or the secondary pulley cylinder chamber 37 via the CVT control unit 9.

  The CVT control unit 9 includes a throttle opening TVO from the throttle opening sensor 10, a primary rotational speed Npri from the primary rotational speed sensor 4, a secondary rotational speed Nsec from the secondary rotational speed sensor 5, and a pulley clamping pressure sensor 14. Pulley clamp pressure etc. are input. A control signal is calculated based on this input signal, and the control signal is output to the hydraulic control valve unit 6.

  The hydraulic control valve unit 6 is input with an accelerator opening, a gear ratio, an input shaft speed, a primary hydraulic pressure, and the like, and performs a shift control by supplying a control pressure to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37. .

  FIG. 2 is a circuit diagram illustrating a transmission hydraulic circuit of the CVT 3.

  The pressure regulator valve (line pressure adjusting valve) 40 regulates the discharge pressure of the oil pump 8 supplied from the oil passage 41 as the line pressure (pulley clamp pressure). A line pressure oil passage 42 is branched from the middle of the oil passage 41. The line pressure oil passage 42 is a pulley clamp pressure supply oil passage that supplies a pulley clamp pressure for clamping the belt 34 to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37 of the CVT 3. The oil passage 43 branched from the line pressure oil passage 42 supplies line pressure (original pressure) to the pilot valve 50.

  Further, the hydraulic pressure of the hydraulic oil drained from the pressure regulator valve 40 is supplied to the clutch regulator valve 60 as the original pressure of the clutch pressure via the first clutch pressure oil passage 46.

  The clutch regulator valve 60 generates a clutch pressure to be supplied to the forward clutch 25 of the forward / reverse switching mechanism 20 and supplies the clutch pressure to the second clutch pressure oil passage 61 branched from the first clutch pressure oil passage 46. The hydraulic pressure in the second clutch pressure oil passage 61 is supplied to the select switching valve 80 and the select control valve 90. A feedback oil passage 63 that branches from the second clutch pressure oil passage 61 and returns to the clutch regulator valve 60 is provided, and a second orifice 64 is provided in the feedback oil passage 63. A bypass oil passage 44 that connects the feedback oil passage 63 and the line pressure oil passage 42 on which the line pressure acts is formed, and a junction between the bypass oil passage 44 and the feedback oil passage 63 is a clutch regulator of the second orifice 64. Provided in the feedback oil passage 63 on the valve 60 side. The bypass oil passage 44 is provided with a first orifice 45. The configuration of the clutch regulator valve 60 will be described in more detail later with reference to FIG.

  The pilot valve 50 to which the line pressure is supplied from the oil passage 53 sets a constant supply pressure to the clutch pressure control solenoid 71 and the select switching solenoid 70 via the oil passage 51. The output pressure of the select switching solenoid 70 is supplied from the oil passage 73 to the select switching valve 80 and controls the operation of the select switching valve 80. The output pressure of the clutch pressure control solenoid 71 is supplied from the oil passage 72 to the select switching valve 80.

  The select switching valve 80 is operated by a select switching solenoid 70. The select switching valve 80 has, as an input port, an oil passage 72 for supplying a signal pressure from the clutch pressure control solenoid 71, a second clutch pressure oil passage 61 through which hydraulic oil regulated by the clutch regulator valve 60 flows, An oil passage 93 through which the hydraulic oil regulated by the select control valve 90 flows is connected. Further, as an output port, an oil passage 81 for supplying hydraulic pressure for fastening the forward clutch 25 to the manual valve 100, an oil passage 82 for supplying hydraulic pressure to a lockup clutch control valve (not shown), and a select control valve 90 An oil passage 83 for supplying hydraulic pressure for operating the spool 92 is connected, and a drain oil passage 84 for draining the hydraulic pressure is connected.

  The select control valve 90 is operated by the hydraulic pressure of the clutch pressure control solenoid 71 supplied from the oil passage 83. The select control valve 90 is connected to an oil path 62 through which the hydraulic oil regulated by the clutch regulator valve 60 flows as an input port, branched from the oil path 61, and further supplies a signal pressure of the clutch pressure control solenoid 71. An oil passage 83 is connected. Then, the hydraulic pressure is regulated by controlling the communication state of the oil passage 62 and the oil passage 93.

  When the signal of the select switching solenoid 70 is ON, the signal pressure of the clutch pressure control solenoid 71 acts as the signal pressure of the select control valve 90 via the select switching valve 80. Then, the hydraulic pressure adjusted by the select control valve 90 is supplied to the manual valve 100. Thereby, when the clutch pressure control solenoid pressure is increased, the select control pressure (that is, the engagement pressure of the forward clutch 25) is decreased.

  When the signal of the select switching solenoid 70 is OFF, the hydraulic pressure adjusted by the clutch regulator valve 60 is supplied to the manual valve 100 without passing through the select control valve 90.

  When the signal of the select switching solenoid 70 is ON and the signal of the clutch pressure control solenoid 71 is zero due to, for example, a failure, the signal pressure to the select control valve 90 is zero. At this time, the spool 92 is moved rightward in the figure by the spring load of the return spring 91 of the select control valve 90. Then, the oil passage 62 and the oil passage 93 are completely communicated, and the maximum engagement pressure is supplied to the forward clutch 25 via the manual valve 100 in the D range state.

  Next, the configuration of the clutch regulator valve 60 will be described with reference to FIG.

  The clutch regulator valve (clutch pressure adjusting valve) 60 is formed in a large-diameter hole 60e formed in the cylinder, and communicates with the pressure regulator valve 40 to supply an upstream port 60a to which clutch pressure (original pressure) is supplied. And a reduced-pressure side pilot that is supplied as a reduced-pressure side pilot pressure from the feedback oil passage 63 through the second orifice 64 from the clutch pressure through a small-diameter hole portion 60f that communicates to the right of the large-diameter hole portion 60e. The port 60b is formed between the upstream port 60a and the pressure reducing pilot port 60b, and is formed on the opposite side of the downstream port 60d across the upstream port 60a and the downstream port 60d communicating with a torque converter regulator valve (not shown). The drain port 60p is formed at the left end of FIG. 2 and is not shown across the orifice 60s. The five main ports of the pressure-increasing side pilot port 60c communicated with the pressure modifier valve, the drain port 60q formed at the connecting portion of the large diameter hole portion 60e and the small diameter hole portion 60f, and each hole portion 60e, A spool 60k formed in a series with lands corresponding to 60f and a return spring 60m for moving the spool 60k to the right in FIG. 2 are provided. The spool 60k is moved to the right by the pilot pressure from the pressure-increasing side pilot port 60c. To do. The spool 60k includes a land 60h for closing the drain port 60p, a land 60i that blocks between the upstream port 60a and the downstream port 60d, and a land 60j that blocks between the downstream port 60d and the drain port 60q. The drain port 60q and the pressure reducing side pilot port 60b are shut off, and a land 60g for receiving a pilot pressure consisting of a partial pressure of the clutch pressure supplied to the pressure reducing side pilot port 60b is formed.

  Therefore, in this clutch regulator valve 60, when the pilot pressure to the pressure increasing side pilot port 60c is low and the clutch pressure acting on the first clutch pressure oil passage 46 is high, the spool 60k is caused by the action of the oil pressure of the feedback oil passage 63. As a result, the amount of hydraulic fluid flowing out from the upstream port 60a to the downstream port 60d increases, so that the torque converter pressure (strictly speaking, the source of the torque converter pressure) supplied from the downstream port 60d to the torque converter regulator valve increases. Pressure) increases. Conversely, when the clutch pressure is not so high, the torque converter pressure (original pressure) does not become so high.

On the other hand, when the modifier control pressure P _L-SOL from the pressure modifier valve supplied to the pressure-increasing side pilot port 60c increases, the spool 60k is moved to the right by an amount corresponding to the modifier control pressure P _L-SOL. The amount of hydraulic oil from the downstream port 60d decreases, and the clutch pressure increases.

  Further, when the clutch pressure is high, or when the pilot pressure acting on the pressure reducing pilot port 60b is high due to the addition of the bypass hydraulic pressure from the bypass oil passage 44, the spool 60k moves to the left and the upstream port 60a to the downstream port 60d. The amount of hydraulic oil flowing out to the engine increases and the clutch pressure is suppressed from increasing. The pilot pressure that is increased by adding the bypass hydraulic pressure from the bypass oil passage 44 acts on the second clutch pressure oil passage 61, but the influence of the second orifice 64 is suppressed. .

  In the transmission hydraulic pressure control device of the CVT 3 configured as described above, the line pressure adjusted by the pressure regulator valve 40 is supplied as the pulley clamp pressure to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37 through the line pressure oil passage 42. , CVT3 is shifted to a predetermined gear ratio.

  Here, when the discharge pressure of the oil pump 8 instantaneously becomes an overpressure state, the pressure regulation of the pressure regulator valve 40 is not in time, and the hydraulic pressure of the first clutch pressure oil passage 46 and the bypass oil passage 44 increases. The bypass oil passage 44 is connected to a feedback oil passage 63 branched from the second clutch pressure oil passage 61 and connected to the clutch regulator valve 60, and a junction portion of the second orifice 64 installed in the feedback oil passage 63. Provided in the downstream part. Therefore, a pressure increase that occurs because the discharge pressure of the oil pump 8 is in an overpressure state first appears as a pressure increase in the downstream portion of the second orifice 64 in the feedback oil passage 63, and as a result, the pressure-reducing pilot of the clutch regulator valve 60. The pilot pressure supplied to the port 60b will rise. When the pilot pressure supplied to the pressure reducing side pilot port 60b increases, the spool 60k moves to the left in FIG. 3, the amount of hydraulic oil flowing from the upstream port 60a to the downstream port 60d increases, and the pressure increases due to overpressure of the oil pump 8. Thus, the hydraulic pressure of the first and second clutch pressure oil passages 46 and 61 connected to the upstream port 60a can be reduced.

  Further, a second orifice 64 is provided in the feedback oil passage 63 branched from the second clutch pressure oil passage 61, and in the feedback oil passage 63 on the downstream side of the orifice 64, that is, between the second orifice 64 and the clutch pressure adjusting valve 60. A bypass oil passage 44 is connected therebetween. For this reason, the hydraulic pressure corresponding to the line pressure from the bypass oil passage 44 acts on the feedback oil passage 63, but the hydraulic pressure of the second clutch pressure oil passage 61 connected to the feedback oil passage 63 is increased by the action of the second orifice 64. Is suppressed.

  As described above, according to the present embodiment, even when the discharge pressure of the oil pump 8 is in an overpressure state, the action of the second orifice 64 installed in the feedback oil passage 63 to which the hydraulic pressure corresponding to the line pressure is supplied. When the upstream port 60a and the downstream port 60d of the clutch regulator valve 60 communicate with each other and the hydraulic oil is discharged, the clutch pressure in the clutch pressure oil passages 46 and 61 is suppressed from being increased. For this reason, even if the discharge pressure of the oil pump 8 is in an overpressure state, such as when the engine is started, the clutch pressure is suppressed from being in an overpressure state, and the forward clutch 25 of the forward / reverse switching mechanism 20 to which the clutch pressure is supplied. It is possible to prevent the durability of the steel from being lowered.

  Further, since the first orifice 45 is provided in the bypass oil passage 44 and the second orifice 64 is provided in the feedback oil passage 63, part of the line pressure supplied from the line pressure oil passage 42 to the bypass oil passage 44 is the orifice 45, 64 and is guided to the second clutch pressure oil passage 61, so that the delay in the rise of the line pressure is suppressed, such as immediately after the engine is started, and a part of the line pressure acts as the clutch pressure. It is possible to achieve both rising pressures.

  FIG. 4 is a circuit diagram showing the transmission hydraulic circuit of the CVT 3 according to the second embodiment of the present invention, and FIG. 5 is a flowchart showing the control contents of the transmission hydraulic control apparatus in the present embodiment. In this embodiment, a switching valve 65 capable of switching the communication state to the bypass oil passage 44 is added to the configuration of the first embodiment. Here, the switching valve 65 is a normally open electromagnetic valve whose communication state is controlled by the CVT control unit 9.

  The transmission hydraulic pressure control of this embodiment will be described using the flowchart of FIG. This control is performed by the CVT control unit 9 at predetermined intervals. The initial control state in the CVT control unit 9 is a start initial flag Fstart which is a flag indicating an initial engine start state (that is, not in the initial start state), and an in-control flag Fctrl which indicates that the shift hydraulic pressure control is being performed. 0 (that is, not under control).

  First, in step S1, it is determined whether or not the engine has been started. As a determination method, for example, it can be determined from the on / off state of the ignition switch. If the engine is in the starting state, the process proceeds to step S2, and if not, the control is terminated.

  In step S2, the state of the start initial flag Fstart is determined in order to determine whether the engine is in the initial start. If the start initial flag Fstart = 0, the process proceeds to step S3 as the initial start, and if Fstart = 1, the control is terminated because it is not the initial start.

  In step S3, in order to determine the communication state of the switching valve 65, it is determined whether or not the in-control flag Fctrl = 0 is established. If Fctrl = 1, the process proceeds to step S5.

  In step S4, the timer count number T of the timer is set to 0, the process proceeds to step S6, the in-control flag Fctrl is set to 1, and the process proceeds to step S7.

  On the other hand, in step S5, the timer count number T is incremented to continue the non-communication state of the bypass oil passage 44 by the switching valve 65, and the process proceeds to step S7.

  In step S7, the switching valve 65 is switched to or maintained in a non-communication state, the bypass oil passage 44 is closed, and the line pressure oil passage 42 and the feedback oil passage 63 are brought into a non-communication state. In step S8, it is determined whether the timer count number T is equal to or greater than a predetermined value. Here, the predetermined value is appropriately set by an experiment or the like in consideration of the balance between the rise of the line pressure and the rise of the clutch pressure. The predetermined value may be variable according to the oil temperature at the time of engine start. If the timer count number T is equal to or greater than a predetermined value, it is determined from the timer count number that the non-communication state of the switching valve 65 has passed a predetermined time, and the process proceeds to step S9. Control is continued assuming that the predetermined time has not elapsed.

  In step S <b> 9, the switching valve 65 is switched to the communication state, the line pressure oil path 42 on which the line pressure acts and the feedback oil path 63 are in a communication state, and a part of the line pressure is applied to the feedback oil path 63. In the next step S10, the in-control flag Fctrl is set to 0, and further in step S11, the start initial flag Fstart is set to 0.

  Thus, in this embodiment, the switching valve 65 is installed in the bypass oil passage 44 in the configuration of the first embodiment, and the switching valve 65 is closed and the bypass oil passage 44 is closed within a predetermined time after the engine is started. Since it is in a non-communication state, at the time of a transient in which the line pressure immediately rises after starting the engine, the line pressure is quickly raised so that the line pressure is preferentially supplied to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37. , Ensure the hydraulic pressure required for shifting. Further, control for preferentially supplying hydraulic pressure to the pulley cylinder chambers 33 and 37 is limited within a predetermined timer count number (= predetermined time) T, and a part of the line pressure is bypassed by the bypass oil passage 44 after the predetermined time has elapsed. Is supplied to the second clutch pressure oil passage 61 so as to accelerate the rise of the clutch pressure. As described above, in this embodiment, in addition to the effects of the first embodiment, the line pressure is preferentially raised until a predetermined time elapses, and after the predetermined time elapses, a part of the line pressure is increased to the clutch pressure. It is possible to achieve both the rise of the line pressure and the rise of the clutch pressure.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea of the present invention.

It is a block diagram of the automatic transmission provided with the belt-type continuously variable transmission in 1st Embodiment. It is a circuit diagram showing the structure of the transmission hydraulic circuit of a belt-type continuously variable transmission. It is sectional drawing showing the structure of a clutch regulator valve. It is a circuit diagram showing the structure of the transmission hydraulic circuit of the belt-type continuously variable transmission in 2nd Embodiment. It is a flowchart which shows the transmission hydraulic pressure control of the belt-type continuously variable transmission in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque converter 2 Lock-up clutch 3 Belt type continuously variable transmission 6 Hydraulic control valve unit 8 Oil pump 9 CVT control unit 10 Throttle opening sensor 12 Engine output shaft 13 Transmission input shaft 14 Pulley clamp pressure sensor 30a Primary pulley 30b Secondary Pulley 33 Primary pulley cylinder chamber 34 Belt 37 Secondary pulley cylinder chamber 38 Driven shaft 40 Pressure regulator valve 41-43 Oil passage (line pressure oil passage)
44 Bypass oil passage 45 First orifice 46 First clutch pressure oil passage 50 Pilot valve 51 Oil passage 60 Clutch regulator valve 61 Second clutch pressure oil passage 62 Oil passage 63 Feedback oil passage 64 Second orifice

Claims (3)

A belt-type continuously variable transmission mechanism comprising a pair of pulleys and a belt suspended between the pulleys;
A forward / reverse switching mechanism that controls the engagement state of the friction clutch to switch the direction of rotation transmitted from the engine to the belt-type continuously variable transmission mechanism;
An oil pump for supplying the belt type continuously variable transmission mechanism with a line pressure necessary for the pulley to clamp the belt;
In the belt type continuously variable transmission equipped with
A line pressure adjusting valve that supplies a line pressure obtained by adjusting the discharge pressure of the oil pump to the belt type continuously variable transmission mechanism via a line pressure oil passage;
The clutch pressure required to engage the friction clutch is generated by adjusting the hydraulic pressure of excess oil drained from the line pressure regulating valve, and this clutch pressure is supplied to the friction clutch via a clutch pressure oil passage. A clutch pressure adjusting valve;
A feedback that supplies a pilot pressure that controls the clutch pressure adjusting valve so that the clutch pressure decreases when the clutch pressure increases from a target pressure when branched from the clutch pressure oil passage and connected to the clutch pressure adjusting valve. Oil passage,
A bypass oil passage connecting the feedback oil passage and the line pressure oil passage, and adding the line pressure to the pilot pressure;
A belt-type continuously variable transmission comprising: a branch portion of the feedback oil passage with the clutch pressure oil passage; and an orifice provided between the junction portion of the bypass oil passage. Hydraulic circuit. The clutch pressure adjusting valve is
A spool positioned according to the pilot pressure;
A supply port to which surplus oil from the line pressure regulating valve is supplied;
According to the position of the spool, a discharge port communicating with the supply port and discharging excess oil,
The bypass hydraulic pressure is added when the hydraulic pressure from the line pressure regulating valve to the clutch pressure regulating valve and the bypass hydraulic pressure of the bypass oil passage rise in an overpressure state where the discharge pressure of the oil pump is excessively increased. Further, the higher the pilot pressure is, the higher the pilot pressure is, the more the flow of excess oil flowing from the supply port to the discharge port increases, the spool moves to suppress the hydraulic pressure to the clutch pressure adjusting valve, and the increased pilot pressure 2. The hydraulic circuit of the belt type continuously variable transmission according to claim 1, wherein an action of the feedback oil passage to the clutch pressure is suppressed by the orifice, and an increase in the clutch pressure is suppressed. A switching valve capable of opening and closing the bypass oil passage;
And a control means for controlling the opening and closing of the switching valve,
2. The hydraulic circuit for a belt-type continuously variable transmission according to claim 1, wherein the control means closes the switching valve and closes the bypass oil passage until a predetermined time elapses after the engine is started. .

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