JP2020016294A - Hydraulic circuit of transmission - Google Patents

Abstract

To provide a hydraulic circuit of a transmission, which can effectively suppress a hunting phenomenon in which a high pressure mode and a low pressure mode are frequently switched, while preventing insufficiency of the hydraulic pressure supplied to a control object.SOLUTION: A hydraulic circuit of a transmission includes a one-way valve (V8) that is interposed between a main pump (PM) and a sub pump (PS) and is opened when the discharge pressure of the sub pump (PS) is higher than the discharge pressure of the main pump (PM), and a fourth oil passage (L4) into which the discharge pressures of the main pump (PM) and sub pump (PS) are supplied. The hydraulic circuit is configured such that, by a solenoid valve (V5) being turned on, or by the hydraulic pressure of the fourth oil passage (L4) becoming equal to or lower than a predetermined value, communication of a first oil passage (L1) and a second oil passage (L2) by a selector valve (V2) is cut off, and only by the solenoid valve (V5) being turned off, the first oil passage (L1) and the second oil passage (L2) are brought into communication with each other by the selector valve (V2).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hydraulic circuit for a transmission, and more particularly, includes a main pump and a sub pump, and supplies oil discharged from the main pump to a shift control system and supplies oil discharged from the sub pump to a lubrication system. The present invention relates to a hydraulic circuit for a transmission.

  Conventionally, as a hydraulic circuit of a transmission mounted on a vehicle, for example, as shown in Patent Document 1, oil is supplied to a pulley oil chamber, a torque converter, and a lubrication system of a transmission by a main pump and a sub pump driven simultaneously by an engine. There is a hydraulic circuit to do. In the hydraulic circuit disclosed in Patent Document 1, by switching the pump shift valve, a low pressure mode (lubrication mode) in which the discharge pressure of the sub pump is supplied to the lubrication system, and a high pressure mode in which the discharge pressure of the sub pump merges with the discharge pressure of the main pump You can switch between modes. Then, when the discharge flow rate of the main pump is insufficient during rapid acceleration or rapid deceleration of the vehicle and the hydraulic pressure of the torque converter or the lubrication system is reduced, by switching from the low pressure mode to the high pressure mode, the oil discharged by the sub pump is reduced. Is switched in the order of the pulley oil chamber, the torque converter, and the lubrication system.

  By the way, the hydraulic circuit described in Patent Document 1 has a circuit configuration in which the condition for switching the pump shift valve is such that the solenoid valve is off and the internal pressure of the torque converter is equal to or higher than a predetermined pressure. As a result, the switching function automatically operates in situations where the line pressure is insufficient even when the low pressure mode is instructed, such as when the solenoid valve is stuck off, and the pump shift valve controls the discharge destination of the sub pump to control the line pressure. To secure.

  However, if the switching condition between the high-pressure mode and the low-pressure mode as described above is fixed, a so-called hunting phenomenon that frequently switches between the low-pressure mode and the high-pressure mode may occur. That is, the internal pressure of the transient torque converter drops → Automatic switching to high pressure mode → The line pressure is satisfied and the internal pressure of the torque converter recovers → Automatic switching to low pressure mode → Transient torque converter There is a possibility that a phenomenon in which the process of lowering the internal pressure is repeated may occur.

Japanese Patent No. 6148354

  The present invention has been made in view of the above-described problem, and an object of the present invention is to prevent a shortage of hydraulic pressure supplied to a control target including a shift control system and a lubrication system, and to reduce a high-pressure mode by changing the hydraulic pressure. To provide a hydraulic circuit for a transmission that can effectively suppress a hunting phenomenon in which switching between the low-pressure mode and the low-pressure mode frequently occurs.

  To achieve the above object, a hydraulic circuit for a transmission according to the present invention includes a main pump (PM) and a sub pump (PS), and supplies oil discharged from the main pump (PM) to at least a first oil supply destination ( 102) and the state where oil discharged from the sub-pump (PS) is supplied to a second oil supply destination (103) and the oil discharged from the main pump (PM) together with the first oil supply destination (PS). A hydraulic circuit (100) for a transmission, wherein the first oil supply destination (102) is higher in pressure than the second oil supply destination (103). And switches communication / non-communication between a first oil passage (L1) connected to the sub-pump (PS) and a second oil passage (L2) connected to the second oil supply destination (103). A switching valve (V2), a solenoid valve (V5) for operating the switching valve (V2) to a position where communication between the first oil passage (L1) and the second oil passage (L2) is cut off, A third oil passage (L3) connecting the main pump (PM) and the sub pump (PS), and a discharge pressure of the sub pump (PS) interposed between the third oil passage (L3) and the main pump (PS). A one-way valve (V8) that opens when the discharge pressure is higher than the discharge pressure of (PM), and a fourth oil passage (L4) to which discharge pressures of the main pump (PM) and the sub-pump (PS) are supplied. The first oil passage (L1) of the switching valve (V2) is connected to the first oil passage (L1) of the switching valve (V2) when the solenoid valve (V5) is turned on, or when the oil pressure of the fourth oil passage (L4) falls below a predetermined value. Communication with the two oil passages (L2) is cut off On the other hand, the first oil passage (L2) and the second oil passage (L2) of the switching valve (V2) are configured to communicate with each other only by turning off the solenoid valve (V5). I do. Further, in this case, the first oil supply destination (102) includes a shift control system (102) for performing a shift control of the transmission (T), and the second oil supply destination (103). ) May include a lubrication system (103) for supplying oil to a lubrication target.

According to the hydraulic circuit of the transmission according to the present invention, the first oil passage and the second oil passage of the switching valve communicate with each other, so that the second pump, to which the discharge pressure of the sub-pump is relatively low, is supplied. While the low pressure mode (lubrication mode) is supplied to the supply destination (lubrication system), the first oil passage and the second oil passage are not connected, so that the discharge pressure of the sub-pump increases and the one-way valve opens. Then, the discharge pressure of the sub-pump merges with the discharge pressure of the main pump to enter a high-pressure mode in which the oil is supplied to a first oil supply destination (shift control system) which is a relatively high-pressure oil supply destination. The high-pressure mode and the low-pressure mode can be switched by switching the communication / non-communication between the first oil passage and the second oil passage of the switching valve by turning on / off the solenoid valve, and switching the fourth oil passage. When the hydraulic pressure becomes equal to or less than a predetermined value, the communication between the first oil passage and the second oil passage is interrupted, and the mode is automatically switched from the low pressure mode to the high pressure mode. Accordingly, control including a first oil supply destination (shift control system) that is a relatively high-pressure oil supply destination and a second oil supply destination (lubrication system) that is a relatively low-pressure oil supply destination in the hydraulic circuit. Insufficient oil pressure supplied to the object can be effectively prevented.
On the other hand, once the high pressure mode is set, the operation returns to the low pressure mode only by turning off the solenoid valve, and if the oil pressure in the fourth oil path returns to an oil pressure exceeding a predetermined value (automatically), the low pressure mode is set. By configuring so as not to return, it is possible to effectively suppress a hunting phenomenon in which switching between the high-pressure mode and the low-pressure mode frequently occurs due to the fluctuation of the hydraulic pressure of the fourth oil passage. Therefore, it is possible to prevent the occurrence of hunting for switching between the high-pressure mode and the low-pressure mode while preventing the hydraulic pressure supplied to the control target from becoming insufficient.

  The hydraulic circuit (100) includes a low-pressure mode in which the first oil passage (L1) and the second oil passage (L2) communicate with each other via the switching valve (V2); L2) and a high pressure mode in which communication between the second oil passage (L2) is interrupted is possible. As the high pressure mode, the first oil passage (L5) is switched on / off by the solenoid valve (V5). L1) and a first high pressure mode in which communication between the second oil passage (L2) is interrupted, and a change in oil pressure in the fourth oil passage (L4), the first oil passage (L1) and the second oil passage. A second high pressure mode in which communication with the road (L2) is interrupted, and the transition from the second high pressure mode to the low pressure mode is performed by turning off the solenoid valve (V5) in the second high pressure mode. By switching on from, it shifts to the first high pressure mode, , The solenoid valve in the first high-pressure mode (V5) may be shifted to the low-pressure mode by switching from ON to OFF.

  According to this configuration, the transition from the second high pressure mode to the low pressure mode, which is achieved by lowering the hydraulic pressure of the fourth oil passage, is performed by switching the solenoid valve from off to on in the second high pressure mode. Then, in the first high-pressure mode, the solenoid valve is switched from on to off to shift to the low-pressure mode, so that unless the solenoid valve is turned on / off, the low-pressure mode is switched to the low-pressure mode. The transition to the mode is not performed. Thereby, when the hydraulic pressure of the fourth oil passage is reduced (automatically) and the system shifts to the high pressure mode (second high pressure mode), even if the hydraulic pressure of the fourth oil passage subsequently recovers, the low pressure mode is automatically set. Therefore, it is possible to more effectively prevent the occurrence of hunting in the high-pressure mode and the low-pressure mode.

  The switching valve (V2) is supplied with a spool (62) that moves forward and backward, an urging means (61) that urges the spool (62) to one side, and a predetermined pressure of the hydraulic circuit (100). A first port (P21), a second port (P22) to which the hydraulic pressure of the fourth oil passage (L4) is supplied, and a third port (P23) to which the output pressure of the solenoid valve (V5) is supplied. The force applied to the spool (62) by the hydraulic pressure of the second port (P22) is increased by the urging force of the urging means (61) and the hydraulic pressure of the first port (P21). When the resultant force is smaller than the resultant force of the first and second oil passages, the spool (62) may be moved to a position where the communication between the first oil passage (L1) and the second oil passage (L2) is interrupted. Good.

  Further, in this case, a step portion (62b) formed in the spool (62) is provided, and the spool (62) blocks communication between the first oil passage (L1) and the second oil passage (L2). When in the position, the hydraulic pressure of the first port (P21) may act on the step (62b).

  According to this configuration, when the hydraulic pressure in the fourth oil passage is reduced (automatically) and the mode shifts to the high-pressure mode (second high-pressure mode) in which communication between the first oil passage and the second oil passage is interrupted, Thereafter, even if the hydraulic pressure of the fourth oil passage recovers, the hydraulic pressure of the first port acts on the step portion of the spool, so that the spool (automatically) connects the first oil passage and the second oil passage. There is no risk of returning to the position. Therefore, since it is not necessary to automatically return from the second high-pressure mode to the low-pressure mode, hunting between the high-pressure mode and the low-pressure mode can be prevented with a simple configuration.

  Further, the fourth oil passage (L4) may be an oil passage communicating with a torque converter (TC), and the oil pressure of the fourth oil passage (L4) may be an internal pressure of the torque converter (TC).

  According to this configuration, since the hydraulic pressure of the fourth oil passage is the internal pressure of the torque converter, particularly, the hunting phenomenon of switching between the high-pressure mode and the low-pressure mode due to the temporary decrease in the internal pressure of the torque converter is prevented. it can. Specifically, the mode is automatically switched to the high-pressure mode with the temporary decrease in the internal pressure of the torque converter, whereby the line pressure is satisfied, the internal pressure of the torque converter is restored, and the mode is automatically switched to the low-pressure mode. The phenomenon that the internal pressure of the torque converter is reduced can be effectively avoided.

  Further, the sub-pump (PS) may have a lower discharge pressure and a higher discharge flow rate than the main pump (PM).

According to this configuration, the sub pump mainly responsible for lubrication has a low discharge pressure and a large discharge flow rate, and the main pump mainly responsible for shift control has a high discharge pressure and a small discharge flow rate. The load can be reduced.
The reference numerals in the parentheses indicate the reference numerals of the corresponding components in the embodiments described later for reference.

  ADVANTAGE OF THE INVENTION According to the hydraulic circuit of the transmission which concerns on this invention, while preventing the shortage of the hydraulic pressure supplied to the control object including a transmission control system and a lubrication system, switching of the high pressure mode and the low pressure mode by the fluctuation | variation of the said hydraulic pressure The hunting phenomenon that frequently occurs can be effectively suppressed.

It is a longitudinal section of a belt type continuously variable transmission. It is a figure showing the hydraulic circuit of the transmission concerning one embodiment of the present invention. It is a figure for explaining a judgment standard of switching of a high pressure mode and a circulation mode in a hydraulic circuit. It is a figure showing a flow of oil in a high pressure mode (forced). FIG. 4 is a diagram illustrating a flow of oil in a lubrication mode when a source pressure of a torque converter is satisfied. FIG. 7 is a diagram illustrating a flow of oil in a lubrication mode when the source pressure of the torque converter starts to decrease. FIG. 4 is a diagram illustrating a flow of oil in a high pressure mode (automatic). It is a figure for explaining switching from a high pressure mode (automatic) to a lubrication mode. It is a figure for explaining switching of a high pressure mode (forced), a high pressure mode (automatic), and a lubrication mode in a hydraulic circuit.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of a belt-type continuously variable transmission mechanism which is one mode of the transmission according to the present invention. First, the overall structure of the belt-type continuously variable transmission T will be described with reference to FIG. The transmission case 11 of the belt-type continuously variable transmission T includes a torque converter case 12 connected to an engine (not shown) and a transmission case body 13 connected to the torque converter case 12. Inside 11, an input shaft 14, a drive pulley shaft 15, a driven pulley shaft 16 and an idle shaft 17 are supported in parallel.

  An input shaft 14 connected to a crankshaft 18 of the engine via a torque converter 19 supports a forward drive gear 21 which can be coupled to the input shaft 14 via a forward clutch 20 so as to be relatively rotatable. The forward drive gear 21 meshes with a forward driven gear 22 fixed to the drive pulley shaft 15. A reverse driven gear 24 that can be coupled to the drive pulley shaft 15 via a reverse clutch 23 is rotatably supported on the drive pulley shaft 15, and the reverse driven gear 24 is supported by an idle shaft 17. The gear 25 meshes with a reverse drive gear 26 fixed to the input shaft 14 via a gear 25.

  A drive pulley 27 supported by the drive pulley shaft 15 and a driven pulley 28 supported by the driven pulley shaft 16 are connected by a metal belt 29, and a pulley oil chamber 27a of the drive pulley 27 and a pulley oil chamber 28a of the driven pulley 28 The ratio between the drive pulley shaft 15 and the driven pulley shaft 16 can be changed by controlling the hydraulic pressure supplied to the drive pulley 27 and changing the groove width of the drive pulley 27 and the driven pulley 28.

  The final drive gear 30 fixed to the driven pulley shaft 16 meshes with the final driven gear 32 fixed to the case of the differential gear 31, and the left and right axles 33, 33 from the differential gear 31 to the outside of the transmission case 11. Extend.

  Therefore, when the forward clutch 20 is engaged and the reverse clutch 23 is disengaged, the driving force of the engine is changed from the crankshaft 18 → the torque converter 19 → the input shaft 14 → the forward clutch 20 → the forward drive gear 21 → Driven gear on the route of forward driven gear 22 → drive pulley shaft 15 → drive pulley 27 → metal belt 29 → driven pulley 28 → driven pulley shaft 16 → final drive gear 30 → final driven gear 32 → differential gear 31 → axle shaft 33,33. Transmitted and cause the vehicle to travel forward.

  When the forward clutch 20 is disengaged and the reverse clutch 23 is engaged, the driving force of the engine is changed from the crankshaft 18 → the torque converter 19 → the input shaft 14 → the reverse drive gear 26 → the idle gear 25 → the reverse. Driven gear 24 → reverse clutch 23 → drive pulley shaft 15 → drive pulley 27 → metal belt 29 → driven pulley 28 → driven pulley shaft 16 → final drive gear 30 → final driven gear 32 → differential gear 31 → axle 33, 33 The reverse rotation is transmitted to the drive wheels to cause the vehicle to travel backward.

  In any of the forward traveling and the reverse traveling, when the groove width of the drive pulley 27 is reduced and the groove width of the driven pulley 28 is increased, the ratio between the drive pulley shaft 15 and the driven pulley shaft 16 is stepless. When the groove width of the driven pulley 27 is decreased by increasing the groove width of the drive pulley 27, the ratio between the drive pulley shaft 15 and the driven pulley shaft 16 is reduced steplessly. The vehicle speed increases.

  FIG. 2 is a diagram illustrating a hydraulic circuit of the transmission according to the embodiment of the present invention. The hydraulic circuit 100 shown in FIG. 1 includes a main pump PM and a sub-pump PS driven by an engine that is a drive source of the belt-type continuously variable transmission T. The characteristics of the main pump PM mainly used for shifting are set such that the discharge pressure is relatively high and the discharge flow rate is set relatively small, and the characteristics of the sub pump PS mainly used for lubrication are that the discharge pressure is relatively low. The discharge flow rate is set relatively large. Thereby, the total drive load of the hydraulic power source of the belt-type continuously variable transmission T can be reduced.

  The oil pumped by the main pump PM from the oil tank 101 is supplied to the sixth oil passage L6, and is supplied to the regulator valve (main regulator valve) V1 from the sixth oil passage L6. The oil that has left the regulator valve V1 is supplied to the TC regulator valve V6 via the fourth oil passage L4 as the original pressure of the torque converter TC, and the pressure is regulated by the TC regulator valve V6 and supplied to the torque converter TC. The oil that has exited the regulator valve V1 is transmitted from the fifth oil passage L5 via the clutch pressure reducing valve V3 to a shift control system of the transmission T such as a clutch oil chamber or a pulley oil chamber (the first oil according to the present invention). Supply destination: a relatively high-pressure oil supply destination) 102.

  The oil pumped by the sub pump PS from the oil tank 101 is supplied to the first oil passage L1, supplied from the first oil passage L1 to the shift valve (switching valve) V2, and supplied from the shift valve V2 to the fourth oil passage L4 and TC. While being supplied to the torque converter TC via the regulator valve V6, the lubrication system of each bearing of the belt-type continuously variable transmission T via the second oil passage L2 (the second oil supply destination according to the present invention: comparison) (A low-pressure oil supply destination) 103.

  The sixth oil passage L6 and the first oil passage L1 are connected via a third oil passage L3, and a one-way valve V8 is arranged in the third oil passage L3. The one-way valve V8 always shuts off the flow of oil from the sixth oil passage L6 to the first oil passage L1, and opens when the discharge pressure of the sub-pump PS is higher than the discharge pressure of the main pump PM. The flow of oil from the oil passage L1 to the sixth oil passage L6 is permitted.

  The regulator valve V1 includes a spool 52 urged to the left by a spring 51. A groove 52a is formed in the spool 52, and a first port P11, a second port P12 facing the outer peripheral surface of the spool 52, and A feedback port P13 is formed. The first port P11 is connected to the sixth oil passage L6 and the fifth oil passage L5, the feedback port P13 is connected to the clutch pressure reducing valve V3 via the fifth oil passage L5, and the second port P12 is connected to the fourth oil passage L5. The shift valve V2 is connected to the second port P22 and the feedback port P26 via the oil passage L4.

  The clutch pressure reducing valve V3 includes a spool 72 urged to the right by a spring 71. A groove 72a is formed in the spool 72, and a first port P31 and a second port P32 facing the outer periphery of the spool 72 are provided. A feedback port P33 is formed. The first port P31 is connected to the regulator valve V1 via the fifth oil passage L5, the second port P32 and the feedback port P33 are connected to the transmission control system 102 via the tenth oil passage L10, and the ninth oil It is connected to a shift inhibitor valve V4 and a shift valve V2 via a path L9.

  The shift valve V2 includes a spool 62 urged rightward by a spring 61. A groove 62a is formed in the spool 62, and a first port P21 and a second port P22 facing the outer peripheral surface of the spool 62. A third port P23, a fourth port P24, a fifth port P25, and a feedback port P26 are formed. The first port P21 is connected to the shift inhibitor valve V4 via the eighth oil passage L8, the second port P22 and the feedback port P26 are connected to the fourth oil passage L4, and the third port P23 is connected to the seventh oil passage L7. And a third port P43 of the shift inhibitor valve V4 is connected to an on / off type solenoid valve V5, a fourth port P24 is connected to the second oil passage L2, and a fifth port P25 is connected to the first oil passage L1. Connected to the sub-pump PS.

  The shift inhibitor valve V4 includes a spool 42 urged rightward by a spring 41. A groove 42a is formed in the spool 42, and a first port P41 and a second port P42 facing the outer peripheral surface of the spool 42. , A third port P43 and a fourth port 44 are formed. The first port P41 is connected to an eighth oil passage L8, the second port P42 is connected to a clutch pressure reducing valve V3 via a ninth oil passage L9, and the third port P43 is connected to a solenoid via a seventh oil passage L7. Connected to valve V5. The fourth port 44 is a drain port, and although not shown, an orifice for restricting the flow rate of oil discharged from the fourth port 44 is provided in an oil passage connected to the fourth port 44. ing.

  In the hydraulic circuit 100 having the above configuration, both the oil discharged from the main pump PM and the oil discharged from the sub-pump PS are supplied to the shift control system 102, and the oil discharged from the main pump PM is controlled by the shift control. A lubrication mode (low pressure mode) in which oil supplied to the system 102 and discharged from the sub pump PS is supplied to the lubrication system 103 can be switched. Furthermore, there are two types of high-pressure modes: a high-pressure mode (forced) and a high-pressure mode (automatic). Details of these two types of high pressure modes will be described later. FIG. 3 is a diagram for describing switching determination between the high pressure mode and the lubrication mode. Switching between the high-pressure mode and the lubrication mode is performed using “high-pressure mode fixing determination”, “running state determination”, and “flow rate balance determination” described later.

  FIG. 3A is a diagram illustrating a graph used for the “high-pressure mode fixing determination”, and is a graph illustrating a relationship between the oil temperature t and the oil pressure P. In the “high-pressure mode fixed determination”, as shown in the graph of FIG. 10, a region of high oil pressure (oil pressure P> P1) (high oil pressure high-pressure mode fixed region) A, which is a region requiring a larger flow rate, and a stepless The high-pressure mode is fixed in an extremely low-temperature (oil temperature t <t1) region (ultra-low-temperature high-pressure mode fixed region) B in which the response of the transmission mechanism T deteriorates. In the other area C, switching between the high-pressure mode and the lubrication mode is executed according to the flow rate balance condition.

  In the "running state determination", as shown in FIG. 3 (b), when there is an operation that is expected to require a large amount of flow rate transiently, the high pressure mode is set in advance and the high pressure mode is fixed. As an example of such an operation, FIG. 5 shows that the transmission range of the transmission is a range other than the D range (running range), that the accelerator is off, that kick-down is being performed, and that paddle mode is being performed. , A manual shift, a stall, and an LC slip. In any of these cases, the high-pressure mode is fixed.

  In the "flow rate balance determination", when the high-pressure mode fixed determination and the traveling state determination determine that the switching is permitted, the flow rate balance when only the oil (flow rate) discharged from the main pump PM is calculated. I do. Specifically, when the discharge amount of the main pump is the supply amount, the total amount of the oil consumption of the torque converter, the leakage amount, the oil consumption during shifting, etc. is the consumption amount, and the supply amount is sufficiently higher than the consumption amount. (If the supply amount is sufficient), switch to the lubrication mode.

FIG. 4 is a hydraulic circuit diagram showing the flow of oil in the high-pressure mode (forced). In the high pressure mode (forced), the solenoid valve V5 is turned on. Further, the source pressure (internal pressure) of the torque converter TC (the hydraulic pressure applied to the shift valve V2 via the fourth oil passage L4) may be either a full state or a low state. In this state, when the output pressure (drain pressure) of the solenoid valve V5 acts on the third port P23 of the shift valve V2, the spool 62 of the shift valve V2 is urged rightward in the drawing. At this time, the output pressure of the solenoid valve V5 applied to the spool 62 is Fsol, the urging force of the spring 61 applied to the spool 62 is Fspg, and the torque converter TC applied to the spool 62 via the fourth oil passage L4 and the second port P22. If the pressure is Ftc,
Fsol + Fspg> Ftc
Accordingly, the spool 62 of the shift valve V2 strokes to a position where the fifth port P25 is closed. As a result, the oil discharged from the sub pump PS merges with the oil discharged from the main pump PM via the one-way valve V8 of the third oil passage L3. The combined oil is regulated by the regulator valve V1 to become a line pressure.

FIG. 5 is a hydraulic circuit diagram showing the flow of oil in the lubrication mode (when the original pressure is satisfied). In the lubrication mode (when the original pressure is satisfied), the solenoid valve V5 is turned off. The source pressure of the torque converter TC is in a full state (a state where the pressure is regulated by the TC regulator valve V6). In this state, the original pressure of the torque converter TC applied to the spool 62 of the shift valve V2 via the fourth oil passage L4 and the second port P22 urges the spool 62 to the left in the drawing,
Fspg <Ftc
Thus, the shift valve V2 connects the fifth port P25 and the fourth port P24. Thus, the oil discharged from the sub pump PS flows into the second oil passage L2 and is supplied to the lubrication system 103. Further, at this time, the spool 42 of the shift inhibitor valve V4 is urged by the spring 41 and strokes rightward to communicate the first port P41 with the second port P42. The hydraulic pressure supplied does not act on the shift valve V2.

FIG. 6 is a hydraulic circuit diagram showing the flow of oil in the lubrication mode (when the original pressure decreases). In the lubrication mode (when the original pressure decreases), the solenoid valve V5 is turned off. Further, the source pressure of the torque converter TC is in a state where the reduction has started. Even if the source pressure of the torque converter TC starts to decrease,
Fspg = Ftc
The spool 62 of the shift valve V2 moves rightward in the figure until the position becomes. At this time, the step 62b of the spool 62 of the shift valve V2 has not reached the first port P21. Therefore, the hydraulic pressure supplied from the first port P41 via the eighth oil passage L8 still does not act on the shift valve V2.

FIG. 7 is a hydraulic circuit diagram showing a flow of oil in a high pressure mode (automatic). In the high pressure mode (automatic), the solenoid valve V5 is turned off. Further, the source pressure of the torque converter TC may be either a full state or a low state. In this state, the original pressure of the torque converter TC becomes equal to or lower than the specified pressure, and the stepped portion 62b of the spool 62 approaches the first port P21 of the shift valve V2, so that the oil is supplied from the eighth oil passage L8 to the first port P21. Is applied to the step 62b. If the hydraulic pressure applied to the step 62b is Fpi,
Fspg + Fpi> Ftc
As a result, the spool 62 of the shift valve V2 moves to the right end and closes the fifth port P25. Therefore, the oil discharged from the sub pump PS merges with the oil discharged from the main pump PM via the one-way valve V8 of the third oil passage L3. The combined oil is regulated by the regulator valve V1 to become a line pressure. As a result, the line pressure is satisfied and the original pressure of the torque converter TC is restored, but the oil pressure Fpi applied to the step portion 62b does not return to zero. Therefore, the spool 62 of the shift valve V2 does not move from the right end. Thus, even if the solenoid valve V5 is turned off and the internal pressure of the torque converter TC is satisfied, the mode does not shift to the lubrication mode. That is, by setting the urging force of the spring 61 of the shift valve V2 and applying the oil pressure supplied from the eighth oil passage L8 via the first port P21 to the step portion 62b of the spool 62, the high pressure mode is once performed. When entering, it does not automatically switch to lubrication mode.

  As described above, once the high pressure mode is set by the automatic switching, even if the original pressure of the torque converter TC is restored, the load (Fpi) due to the hydraulic pressure applied to the step portion 62b of the spool 62 remains. There is no transition to the lubrication mode as indicated by V5. That is, in the hydraulic circuit 100 of the present embodiment, even if the mode is automatically switched to the high pressure mode, the mechanism returns to the lubrication mode again only when it is determined that the high pressure mode is the lubrication mode based on the balance calculation. Therefore, hunting in which the high-pressure mode and the lubrication mode are frequently switched can be avoided.

FIG. 8 is a diagram for explaining a procedure for switching from the high pressure mode (automatic) to the lubrication mode. In the high pressure mode (automatic) shown in FIG.
Fspg + Fpi> Ftc
Accordingly, the spool 62 of the shift valve V2 is in the high pressure mode position. Then, in the high pressure mode (forced) shown in FIG. 8B, the hydraulic pressure is supplied to the third port P43 of the shift inhibitor valve V4 by turning on the solenoid valve V5. As a result, the spool 42 of the shift inhibitor valve V4 returns to the left in the drawing. On the other hand, the spool 62 of the shift valve V2 remains at the same position. In order to shift from the state to the lubrication mode shown in FIG. 8C, the solenoid valve V5 is turned off, and the original pressure of the torque converter TC (the internal pressure in the full state) is supplied to the second port P22 of the shift valve V2. Thus, the spool 62 of the shift valve V2 moves to the left in the drawing, and the fifth port P25 and the fourth port P24 of the shift valve V2 communicate with each other. Thereafter, the spool 42 of the shift inhibitor valve V4 moves to the right in the figure, and the second port P42 and the first port P41 communicate.

  Here, in FIG. 8 (c), after the step portion 62b of the spool 62 of the shift valve V2 is not exposed to the second port P21, the spool 42 of the shift inhibitor valve V4 moves to move to the second port P42. In order to allow the first port P41 to communicate, it is necessary to install an orifice (not shown) in an oil passage communicating with the fourth port P44 of the shift inhibitor valve V4. Thereby, the switching timing of the shift valve V2 and the shift inhibitor valve V4 is adjusted so as to be in the order of the shift valve V2 → the shift inhibitor valve V4.

  FIG. 9 is a diagram for explaining switching in the hydraulic circuit 100 between the high-pressure mode (forced), the high-pressure mode (automatic), and the lubrication mode. As shown in the figure, in the lubrication mode 201, the solenoid valve V5 is turned on (high-pressure mode instruction) to switch to the high-pressure mode (forced) 202 (path 211). Then, in the high pressure mode (forced) 202, when the original pressure of the torque converter TC is satisfied, the solenoid valve V5 is turned off (lubrication mode instruction) (path 212) to enter the lubrication mode 201.

  Further, in the lubrication mode 201, when the source pressure of the torque converter TC is reduced (insufficient), the solenoid valve V5 is turned off (lubrication mode instruction) to change from the lubrication mode 201 to the high pressure mode (automatic) 203. Switching is performed automatically (path 213). On the other hand, in the high-pressure mode (automatic), when the original pressure of the torque converter TC returns (returns to the specified pressure again after falling below the specified pressure at which the automatic switching is performed), the solenoid valve V5 is turned off (lubrication mode instruction). As a result, the high-pressure mode (automatic) is maintained (it does not return to the lubrication mode 201 on the route of the path 214). On the other hand, in the high pressure mode (automatic) 203, when the solenoid valve V5 is turned on (high pressure mode instruction) (path 215), the mode is switched to the high pressure mode (forced) 202.

  That is, once the high pressure mode (automatic) 203 is set, the lubrication mode is not automatically returned to the high pressure mode (forced) 202 by turning on the solenoid valve V5 (high pressure mode instruction).

  As described above, according to the hydraulic circuit 100 of the present embodiment, since the first oil passage L1 and the second oil passage L2 communicate with each other via the shift valve V2, the discharge pressure of the sub-pump PS reduces the lubrication system 103. The first oil passage L1 and the second oil passage L2 are disconnected from each other, while the discharge pressure of the sub-pump PS is increased and the one-way valve V8 is opened. The high pressure mode is set in which the discharge pressure of the sub pump PS joins the discharge pressure of the main pump PM. The high pressure mode and the low pressure mode can be switched by switching on / off of the solenoid valve V5 between communication / non-communication between the first oil passage L1 and the second oil passage L2 by the shift valve V2. When the oil pressure of the fourth oil passage L4 (source pressure of the torque converter TC) becomes equal to or less than a predetermined value, the communication between the first oil passage L1 and the second oil passage L2 is cut off (automatically), and the low oil pressure mode changes to the high oil pressure. Switching to the mode is performed. As a result, it is possible to effectively prevent the hydraulic circuit 100 from running out of hydraulic pressure supplied to the control target including the transmission control system 102 and the lubrication system 103.

  On the other hand, once the high pressure mode is set, the operation returns to the low pressure mode only by turning off the solenoid valve V5, and when the hydraulic pressure of the fourth oil passage L4 returns to a hydraulic pressure exceeding a predetermined value (automatically), the low pressure mode is set. By configuring so as not to return to the mode, it is possible to effectively suppress a hunting phenomenon in which switching between the high-pressure mode and the low-pressure mode frequently occurs due to a change in the hydraulic pressure of the fourth oil passage L4. Therefore, it is possible to prevent the occurrence of hunting for switching between the high-pressure mode and the low-pressure mode while preventing the hydraulic pressure supplied to the control target from becoming insufficient.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications may be made within the scope of the claims and the technical idea described in the specification and the drawings. Deformation is possible. For example, in the above embodiment, the case where the relatively high-pressure oil supply destination according to the present invention is the transmission control system 102 and the relatively low-pressure oil supply destination is the lubrication system 103 has been described. In addition to the above-described shift control system 102, other controlled objects such as the torque converter 19 can be included as the supply destinations of the high-pressure oil. Further, as the oil supply destination of the relatively low pressure according to the present invention, a low pressure oil supply destination other than the lubrication system 103 can be included.

DESCRIPTION OF SYMBOLS 11 Transmission case 12 Torque converter case 13 Transmission case main body 14 Input shaft 15 Drive pulley shaft 16 Driven pulley shaft 17 Idle shaft 18 Crankshaft 19 Torque converter 20 Forward clutch 21 Forward drive gear 22 Forward driven gear 23 Reverse clutch 24 Reverse driven gear 25 Idle gear 26 Reverse drive gear 27 Drive pulley 27a Pulley oil chamber 28 Driven pulley 28a Pulley oil chamber 29 Metal belt 30 Final drive gear 31 Differential gear 32 Final driven gear 33, 33 Axle 41 Spring 42 Spool 42a Groove 51 Spring 52 Spool 52a Groove 61 Spring 62 Spool 62a Groove 62b Step 71 Spring 72 Spool 72 a Groove 100 Hydraulic circuit 101 Oil tank 102 Shift control system 103 Lubrication system 201 Lubrication mode 202 High pressure mode (forced)
203 High pressure mode (automatic)
PM Main pump PS Sub pump T Belt type continuously variable transmission TC Torque converter V1 Regulator valve V2 Shift valve V3 Clutch pressure reducing valve V4 Shift inhibitor valve V5 Solenoid valve V6 TC regulator valve V8 One-way valve

Claims (7)

With main pump and sub pump,
While supplying the oil discharged by the main pump to at least a first oil supply destination,
A hydraulic circuit for a transmission that can select between a state in which oil discharged from the sub-pump is supplied to a second oil supply destination and a state in which oil discharged from the main pump is supplied to the first oil supply destination together with oil discharged from the main pump. ,
The first oil supply destination is an oil supply destination at a higher pressure than the second oil supply destination,
A switching valve for switching communication / non-communication between a first oil passage connected to the sub-pump and a second oil passage connected to the second oil supply destination;
A solenoid valve for operating the switching valve to a position at which communication between the first oil passage and the second oil passage is interrupted;
A third oil passage connecting the main pump and the sub pump,
A one-way valve interposed in the third oil passage and opening when the discharge pressure of the sub-pump is higher than the discharge pressure of the main pump;
A fourth oil passage to which a discharge pressure of the main pump and the sub-pump is supplied,
While the solenoid valve is turned on, or the oil pressure of the fourth oil passage becomes equal to or less than a predetermined value, the communication between the first oil passage and the second oil passage of the switching valve is interrupted,
A hydraulic circuit for a transmission, wherein the first oil passage and the second oil passage of the switching valve communicate with each other only by turning off the solenoid valve. The first oil supply destination includes a shift control system for performing shift control of the transmission,
The hydraulic circuit of a transmission according to claim 1, wherein the second oil supply destination includes a lubrication system that supplies oil to a lubrication target. The hydraulic circuit,
A low pressure mode in which the first oil passage communicates with the second oil passage via the switching valve, and a high pressure mode in which communication between the first oil passage and the second oil passage is interrupted are possible. ,
As the high pressure mode,
A first high pressure mode in which communication between the first oil passage and the second oil passage is interrupted by switching on / off of the solenoid valve;
A second high-pressure mode in which communication between the first oil passage and the second oil passage is interrupted by a change in oil pressure of the fourth oil passage;
The transition from the second high-pressure mode to the low-pressure mode is performed by switching the solenoid valve from off to on in the second high-pressure mode to the first high-pressure mode, and thereafter, in the first high-pressure mode, The hydraulic circuit of a transmission according to claim 1 or 2, wherein the mode shifts to the low pressure mode when a solenoid valve is switched from on to off. The switching valve,
A spool that moves forward and backward,
Urging means for urging the spool to one side,
A first port to which a predetermined pressure of the hydraulic circuit is supplied;
A second port to which the hydraulic pressure of the fourth oil passage is supplied;
A third port to which the output pressure of the solenoid valve is supplied,
When the force applied to the spool by the hydraulic pressure of the second port becomes smaller than the resultant force of the urging force of the urging means and the force applied to the spool by the hydraulic pressure of the first port, the spool is connected to the first oil passage. The hydraulic circuit for a transmission according to claim 2, wherein the hydraulic circuit is configured to move to a position at which communication with the second oil passage is interrupted. A step formed on the spool,
5. A structure in which the hydraulic pressure of the first port acts on the step when the spool is at a position where the communication between the first oil passage and the second oil passage is interrupted. 2. The hydraulic circuit of the transmission according to claim 1. The fourth oil passage is an oil passage communicating with a torque converter,
The hydraulic circuit for a transmission according to claim 1, wherein the hydraulic pressure of the fourth oil passage is an internal pressure of the torque converter. The hydraulic circuit of a transmission according to any one of claims 1 to 5, wherein the sub-pump has a lower discharge pressure and a higher discharge flow rate than the main pump.