JP2005299803A - Hydraulic control device for vehicular belt continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic control device for improving the responsiveness of a vehicular belt continuously variable transmission during sudden down-shift. <P>SOLUTION: The hydraulic control device for the belt continuously variable transmission comprises at least one of shift control hydraulic pressure chambers PC1, PC2 for changing the groove width of a pulley on a primary side and two hydraulic pressure chambers PCI, PCO for generating tension control belt clamping force on a movable sheave on a secondary side. In predetermined operating conditions, operating oil is drained from one hydraulic pressure chamber PCO of the two hydraulic pressure chambers on the secondary side. During sudden down-shift in the predetermined operating conditions, operating oil is supplied from the shift control hydraulic pressure chambers PC1, PC2 on the primary side to one hydraulic pressure chamber PCO. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic control device for a belt-type continuously variable transmission for a vehicle, and in particular, transmits power between two variable pulleys by a belt and changes the belt winding radius to change the gear ratio. The present invention relates to a hydraulic control device for a belt type continuously variable transmission for a vehicle configured to be controlled.

  In general, a stepped or continuously variable transmission is provided on the output side of the engine for the purpose of operating the engine under optimum conditions according to the traveling state of the vehicle. An example of such a continuously variable transmission is a belt-type continuously variable transmission. This belt-type continuously variable transmission has two rotating members arranged in parallel, and a primary pulley and a secondary pulley separately attached to each rotating member. Both the primary pulley and the secondary pulley are configured by combining a fixed sheave and a movable sheave, and a V-shaped groove is formed between the fixed sheave and the movable sheave.

  Further, a belt is wound around the groove of the primary pulley and the groove of the secondary pulley, and a hydraulic chamber for generating a holding pressure in the axial direction is separately provided on the movable sheave. By separately controlling the hydraulic pressure in each hydraulic chamber, the groove width of the primary pulley is controlled to change the belt wrapping radius and the gear ratio is changed, while the groove width of the secondary pulley is changed. The belt tension is controlled.

  By the way, in the belt type continuously variable transmission as described above, since the hydraulic chamber is provided on the outer peripheral side of the rotating member, hydraulic pressure generated by centrifugal force, so-called centrifugal hydraulic pressure, acts on the hydraulic chamber, May be higher than the control target hydraulic pressure. As a result, the clamping force of the belt is increased, the belt transmission efficiency is deteriorated, and the adverse effect on the belt durability is known. An example of a belt-type continuously variable transmission as a measure for solving such inconvenience due to centrifugal hydraulic pressure is described in Patent Document 1.

  In the belt-type continuously variable transmission described in Patent Document 1, a secondary pulley provided on a secondary shaft is movable in an axial direction on a fixed sheave integrally formed with the secondary shaft and the secondary shaft. A first hydraulic chamber that presses the movable sheave in the axial direction, and a second pressure that applies a pressing force opposite to the pressing force of the first hydraulic chamber to the movable sheave. The oil passage forming member is disposed in the passage of the oil passage communicated with the second hydraulic chamber. Further, the oil passage forming member is attached to the secondary shaft, bearings and partition walls are disposed on both sides thereof, and an oil passage is provided in the secondary shaft. The second portion is provided by a notch provided in the oil passage forming member. The hydraulic chamber is configured to communicate with the oil passage.

  Similarly, Patent Document 2 discloses another example of a belt type continuously variable transmission provided with a centrifugal pressure compensator for eliminating the disadvantage caused by centrifugal hydraulic pressure.

  The centrifugal pressure compensator in the belt-type continuously variable transmission described in Patent Document 2 includes another cylinder and a pulley shaft fixed to a sheave movable in the axial direction, radially outward of the piston / cylinder assembly. A separate piston fixed to the cylinder, and the separate piston and the separate cylinder form a separate piston / cylinder assembly.

JP 2001-323978 A JP 2000-27959 A

  By the way, in the pulley provided with two hydraulic chambers like the belt type continuously variable transmission described in the above Patent Documents 1 and 2, the hydraulic oil in one hydraulic chamber is drained according to the operating conditions, It is conceivable to reduce the influence of centrifugal oil pressure. Under such operating conditions, a sudden downshift is required to increase the gear ratio during sudden acceleration or braking of the vehicle, but when the hydraulic oil in one hydraulic chamber is drained as described above, There was a problem that a sufficient amount of hydraulic pressure required to move the movable sheave rapidly could not be obtained and the responsiveness was not good.

  The present invention has been made against the background of the above circumstances, and an object thereof is to provide a hydraulic control device for a belt-type continuously variable transmission for a vehicle that can improve the responsiveness during a sudden downshift.

In order to achieve the above object, a hydraulic control device for a belt type continuously variable transmission for a vehicle according to one aspect of the present invention includes at least one transmission control hydraulic chamber for changing a groove width of a primary pulley. In a hydraulic control device for a belt-type continuously variable transmission that includes two hydraulic chambers that generate a tension control belt clamping pressure that acts on the movable sheave on the secondary side. The hydraulic oil is drained from one of the two hydraulic chambers, and at the time of a sudden downshift in the predetermined operating condition, the hydraulic oil is supplied from the primary-side shift control hydraulic chamber to the one hydraulic chamber. It is configured as described above.

  Here, the two hydraulic chambers on the secondary side are an outer diameter side hydraulic chamber and an inner diameter side hydraulic chamber, and the one hydraulic chamber to which the hydraulic oil is drained is an outer diameter side hydraulic chamber. preferable.

  According to one aspect of the present invention, at least one shift control hydraulic chamber for changing the groove width of the primary pulley and two tension generating belt clamping pressures acting on the secondary movable sheave. In a hydraulic control device for a belt-type continuously variable transmission including a hydraulic chamber, during a sudden downshift in a predetermined operating condition in which hydraulic oil is drained from one of the two hydraulic chambers on the secondary side, Since hydraulic oil is supplied from the primary-side shift control hydraulic chamber to the one hydraulic chamber, a large amount of hydraulic oil is quickly supplied to the one hydraulic chamber, and centrifugal hydraulic pressure is generated to move the movable sheave. Power increases. That is, the movable sheaves on the primary side and the secondary side are moved quickly, and the responsiveness of the sudden downshift is improved.

  Here, the two hydraulic chambers on the secondary side are an outer diameter side hydraulic chamber and an inner diameter side hydraulic chamber, and the one hydraulic chamber into which the hydraulic oil is drained is an outer diameter side hydraulic chamber. According to this, centrifugal hydraulic pressure can be used effectively.

Here, embodiments of the present invention will be specifically described with reference to the drawings.
(1) Configuration of Transaxle FIG. 1 is a skeleton diagram of a transaxle when the belt-type continuously variable transmission of the present invention is applied to an FF vehicle (front-wheel drive vehicle in front of an engine). In FIG. 1, reference numeral 1 denotes an engine as a driving force source of a vehicle, and the type thereof is not particularly limited. In the following description, a case where a gasoline engine is used as the engine 1 will be described for convenience. A transaxle 3 is provided on the output side of the engine 1, and this transaxle 3 is attached to a transaxle housing 4 attached to the rear end side of the engine 1 and an open end opposite to the engine 1. A transaxle case 5 and a transaxle rear cover 6 attached to an opening end opposite to the transaxle housing 4 are sequentially provided. A torque converter 7 is provided inside the transaxle housing 4, and a forward / reverse switching mechanism 8, a belt type continuously variable transmission (CVT) 9, and a final one are arranged inside the transaxle case 5 and the transaxle rear cover 6. A reduction gear 10 is provided.

  An input shaft 11 coaxial with the crankshaft 2 is provided inside the transaxle housing 4, and a turbine runner 13 is attached to an end of the input shaft 11 on the engine 1 side. On the other hand, a front cover 15 is connected to the rear end of the crankshaft 2 via a drive plate 14, and a pump impeller 16 is connected to the front cover 15. The turbine runner 13 and the pump impeller 16 are disposed to face each other, and a stator 17 is provided inside the turbine runner 13 and the pump impeller 16. An oil pump 20 is provided between the torque converter 7 and the forward / reverse switching mechanism 8.

  The forward / reverse switching mechanism 8 is provided in a power transmission path between the input shaft 11 and the belt type continuously variable transmission 9. The forward / reverse switching mechanism 8 has a planetary gear mechanism 24 of a double pinion type. The planetary gear mechanism 24 includes a sun gear 25 provided on the input shaft 11, a ring gear 26 disposed concentrically with the sun gear 25 on the outer peripheral side of the sun gear 25, a pinion gear 27 meshed with the sun gear 25, A pinion gear 28 meshed with the pinion gear 27 and the ring gear 26, a carrier 29 that holds the pinion gears 27, 28 so as to be able to rotate, and holds the pinion gears 27, 28 in an integrally revolving state around the sun gear 25. have. And this carrier 29 and the primary shaft 30 mentioned later of the belt-type continuously variable transmission 9 are connected. A forward clutch CL for connecting / disconnecting the power transmission path between the carrier 29 and the input shaft 11 and a reverse brake BR for controlling rotation / fixation of the ring gear 26 are provided.

  The belt type continuously variable transmission 9 includes a primary shaft (drive side shaft) 30 disposed concentrically with the input shaft 11 and a secondary shaft (driven side shaft) 31 disposed in parallel to the primary shaft 30. ing. The primary shaft 30 is rotatably held by bearings 32 and 33, and the secondary shaft 31 is rotatably held by bearings 34 and 35, respectively.

  A primary pulley 36 is provided on the primary shaft 30 side, and a secondary pulley 37 is provided on the secondary shaft 31 side. The primary pulley 36 has a fixed sheave 38 formed integrally with the primary shaft 30 and a movable sheave 39 configured to be movable in the axial direction of the primary shaft 30. A V-shaped groove 40 is formed between the opposed surfaces of the fixed sheave 38 and the movable sheave 39.

  In addition, a hydraulic actuator 41 that moves the movable sheave 39 and the fixed sheave 38 closer to and away from each other by operating the movable sheave 39 in the axial direction of the primary shaft 30 is provided. On the other hand, the secondary pulley 37 similarly has a fixed sheave 42 formed integrally with the secondary shaft 31 and a movable sheave 43 configured to be movable in the axial direction of the secondary shaft 31. A V-shaped groove 44 is formed between the surfaces facing the movable sheave 43. Further, a hydraulic actuator 45 that moves the movable sheave 43 and the fixed sheave 42 closer to and away from each other by operating the movable sheave 43 in the axial direction of the secondary shaft 31 is provided.

  A belt 46 is wound around the groove 40 of the primary pulley 36 and the groove 44 of the secondary pulley 37. The belt 46 includes a large number of metal pieces and a plurality of steel rings. A counter drive gear 47 is fixed to the secondary shaft 31 and is held by bearings 48 and 49. Further, the bearing 35 described above is provided on the transaxle rear cover 6 side, and a parking gear 31 </ b> A is provided between the bearing 35 and the secondary pulley 37.

  Further, an intermediate shaft 50 parallel to the secondary shaft 31 is supported by bearings 51 and 52 in the power transmission path between the counter drive gear 47 and the final reduction gear 10 of the belt type continuously variable transmission 9. ing. The intermediate shaft 50 is provided with a counter driven gear 53 that meshes with the counter drive gear 47 and a final drive gear 54.

  On the other hand, the final reduction gear 10 has a hollow differential case 55 rotatably supported by bearings 56 and 57, and a ring gear 58 that meshes with the final drive gear 54 is provided on the outer periphery of the differential case 55. A pinion shaft 59 to which two pinion gears 60 are attached is disposed inside the differential case 55. Two side gears 61 are meshed with the pinion gear 60 and communicated with the wheels 63 via the left and right drive shafts 62, respectively.

  Here, the first embodiment of the belt-type continuously variable transmission 9 described above will be described in detail with reference to FIG. 2A and 2B are enlarged cross-sectional views in the vicinity of the primary pulley 36 and the secondary pulley 37, respectively.

(2) Configuration of Primary Pulley 36 The primary pulley 36 is disposed on the outer periphery of the primary shaft 30 between a bearing 33 attached to the transaxle rear cover 6 and a bearing 32 attached to the transaxle case 5 side. Yes. The primary shaft 30 is rotatable about the axis A <b> 1, and two oil passages 107 and 108 are formed in the primary shaft 30 in the axial direction. The oil passages 107 and 108 are communicated with a hydraulic circuit 200 of a hydraulic control device described later. Further, the primary shaft 30 is provided with oil passages 109 and 110 that extend in the radial direction toward the outer peripheral surface thereof and communicate with the oil passage 107. The oil passage 109 and the oil passage 110 are provided at different positions in the axial direction. Specifically, the oil passage 109 is disposed closer to the bearing 33 than the oil passage 110. Furthermore, an oil passage 111 that extends in the radial direction toward the outer peripheral surface of the primary shaft 30 and communicates with the oil passage 108 is provided. The oil passage 111 is opened between the movable sheave 39 and the fixed sheave 38 and supplies oil that lubricates the belt 46.

  On the other hand, a step 112 is formed between the opening of the oil passage 109 on the outer periphery of the primary shaft 30 and the bearing 33 so as to face the bearing 33. The movable sheave 39 includes an inner cylindrical portion 39A that slides along the outer peripheral surface of the primary shaft 30, a radial direction portion 39B that continues from the end of the inner cylindrical portion 39A on the fixed sheave 38 side toward the outer peripheral side, The outer cylindrical portion 39C is continuous with the outer peripheral end of the direction portion 39B and extended in the axial direction toward the bearing 33 side. An oil passage 116 penetrating from the inner peripheral surface to the outer peripheral surface is formed in the inner cylindrical portion 39A. The oil passage 116 and the oil passage 110 communicate with each other via an annular notch 115 formed on the outer peripheral surface of the primary shaft 30.

  A partition wall 117 is disposed between the movable sheave 39 and the bearing 33. The partition wall 117 includes a radial portion 117A that forms the inner peripheral side of the partition wall 117, and a cylindrical portion that is continuous to the outer peripheral end of the radial direction portion 117A and that extends toward the radial direction portion 39B of the movable sheave 39. 117B, and a radial portion 117C that is continuous with the end of the movable sheave 39 on the radial direction 39B side of the cylindrical portion 117B and extends outward. The radial direction portion 117 </ b> A of the partition wall 117 is disposed between the stepped portion 112 and the bearing 33. A resin seal ring 117D is attached to the outer peripheral end of the radial direction portion 117C of the partition wall 117, and the seal ring 117D and the inner peripheral surface of the outer cylindrical portion 39C of the movable sheave 39 are relatively movable in the axial direction. In this state, a seal surface is formed at the contact portion. As described above, the first hydraulic chamber PC1 is formed in the space surrounded by the movable sheave 39 and the partition wall 117. The first hydraulic chamber PC1 and the oil passage 116 are communicated with each other.

  An axial groove 123 is formed on the inner peripheral surface of the inner cylindrical portion 39 </ b> A of the movable sheave 39, and an axial groove 124 is formed on the outer peripheral surface of the primary shaft 30. A plurality of grooves 123 and 124 are formed at predetermined intervals in the circumferential direction. The primary shaft 30 and the movable sheave 39 are positioned so that each groove 123 and each groove 124 have the same phase in the circumferential direction, and a plurality of balls 125 straddling both the groove 123 and the groove 124 are arranged. Has been. The primary shaft 30 and the movable sheave 39 can be smoothly moved relative to each other in the axial direction by the grooves 123 and 124 and the ball 125, but the primary shaft 30 and the movable sheave 39 cannot be relatively moved in the circumferential direction. It is supposed to be in a state.

  Further, an annular cylinder member 126 is attached to the outer periphery of the primary shaft 30. The cylinder member 126 includes a radial direction portion 126A and a cylindrical portion 126B that is continuous on the outer peripheral side of the radial direction portion 126A and that extends in the axial direction toward the fixed sheave 38 side. The inner diameter of the cylindrical portion 126B is set larger than the outer diameter of the outer cylindrical portion 39C of the movable sheave 39.

  An inner peripheral portion of the radial direction portion 126A of the cylinder member 126 having the above-described configuration is disposed between the bearing 33 and the radial direction portion 117A of the partition wall 117. Further, a nut 130 is fastened and fixed to the outer periphery of the primary shaft 30, and the bearing 33, the cylinder member 126, and the partition wall 117 are clamped in the axial direction of the primary shaft 30 by the nut 130 and the step portion 112, and The positioning is fixed in the axial direction.

  In addition, there is a piston between the cylindrical portion 117B of the partition wall 117 and the cylindrical portion 126B of the cylinder member 126, and between the radial direction portion 126A of the cylinder member 126 and the outer cylindrical portion 39C of the movable sheave 39. 131 is provided. The piston 131 is formed in a substantially disk shape. An O-ring 131A made of a rubber-like elastic material is attached to the inner periphery of the piston 131, and a resin seal ring 131B is attached to the outer periphery of the piston 131. It has been. The piston 131 is configured to be movable in the axial direction with respect to the partition wall 117 and the cylinder member 126. The O-ring 131A contacts the outer peripheral surface of the cylindrical portion 117B of the partition wall 117 to form a seal surface. 131B contacts the inner peripheral surface of the cylindrical portion 126B of the cylinder member 126 to form a seal surface. Furthermore, a cylindrical sleeve 131 </ b> C that is extended in the axial direction toward the bearing 33 side is formed at the inner peripheral end of the piston 131.

  Thus, the second hydraulic chamber PC2 is formed in an annular space surrounded by the cylinder member 126, the partition wall 117, and the piston 131. Further, an oil passage 135 that penetrates the partition wall 117 in the thickness direction is formed at a boundary portion between the radial direction portion 117A and the cylindrical portion 117B of the partition wall 117, and the first hydraulic chamber PC1 and the second hydraulic pressure are formed. The chamber PC2 communicates with the oil passage 135. In addition, an air chamber 136 is formed in a space surrounded by the partition wall 117, the piston 131, and the outer cylindrical portion 39 </ b> C of the movable sheave 39, and an air passage 137 that connects the air chamber 136 and the outside of the cylinder member 126 is provided. ing.

(3) Configuration of Secondary Pulley 37 FIG. 2B is a cross-sectional view showing a specific configuration near the secondary shaft 31. The secondary pulley 37 is disposed between the bearing 34 and the bearing 35 on the outer periphery of the secondary shaft 31. The secondary shaft 31 is rotatable about the axis B <b> 1, and two oil passages 178 and 179 are formed in the secondary shaft 31 in the axial direction. These oil passages 178 and 179 are communicated with a hydraulic circuit 200 of a hydraulic control device described later. Furthermore, an oil passage 180 that extends in the radial direction toward the outer peripheral surface of the secondary shaft 31 and communicates with the oil passage 178 is provided. Furthermore, an oil passage 181 that extends in the radial direction toward the outer peripheral surface of the secondary shaft 31 and communicates with the oil passage 179 is provided. Furthermore, a step portion 31 </ b> B is formed between the opening portion of the oil passage 181 and the bearing 34 on the outer periphery of the secondary shaft 31.

  The movable sheave 43 of the secondary pulley 37 includes a thick cylindrical portion 182 and a radial direction portion 183 that is continuous with the end portion on the fixed sheave 42 side on the outer periphery of the cylindrical portion 182. An annular cylinder member 190 is provided between the step portion 31 </ b> B and the bearing 34. The cylinder member 190 includes a first radial portion 190A, a first cylindrical portion 190B extending from the outer peripheral end of the first radial direction portion 190A toward the radial direction portion 183 of the movable sheave 43, and a first cylindrical portion. The second radial direction portion 190C that extends while curving outward from the end portion in 190B, and is continuous with the outer peripheral side of the second radial direction portion 190C and toward the radial direction portion 183 of the movable sheave 43 A second cylindrical portion 190D extended in the protruding direction.

  An axial groove 182 </ b> B is formed on the inner peripheral surface of the cylindrical portion 182 of the movable sheave 43, and an axial groove 31 </ b> C is formed on the outer peripheral surface of the secondary shaft 31. A plurality of grooves 182B and grooves 31C are formed at predetermined intervals in the circumferential direction. As in the case of the primary shaft 30, the secondary shaft 31 and the movable sheave 43 are positioned so that the grooves 182B and the grooves 31C have the same phase in the circumferential direction. By the groove (spline groove), the secondary shaft 31 and the movable sheave 43 are relatively movable in the axial direction, but are not relatively movable in the circumferential direction.

  On the other hand, the movable sheave 43 is provided with an annular member 195. The annular member 195 has a radial direction portion 195A fixed to the radial direction portion 183 of the movable sheave 43 and a cylindrical portion 195B extended from the outer peripheral end toward the cylinder member 190 side. Here, a resin seal ring 195C is attached to the cylindrical portion 195B, and comes into contact with the inner peripheral surface of the second cylindrical portion 190D of the above-described cylinder member 190 in a state of being relatively movable in the axial direction. A sealing surface is formed on the portion.

  The outer peripheral surface of the cylindrical portion 182 of the movable sheave 43 and the inner peripheral surface of the first cylindrical portion 190B of the cylinder member 190 are fitted so as to be relatively movable, and the end surface of the cylindrical portion 182, the cylinder member 190, and the secondary shaft 31. A hydraulic chamber PCI on the inner diameter side is formed in a space surrounded by the outer peripheral surface. The inner diameter side hydraulic chamber PCI communicates with the oil passage 181.

  On the other hand, an outer diameter side hydraulic chamber PCO is formed in a space surrounded by the outer peripheral surface of the cylindrical portion 182 of the movable sheave 43, the annular member 195, and the cylinder member 190. The outer-diameter hydraulic chamber PCO communicates with an oil passage 182A formed in the radial direction in the cylindrical portion 182 of the movable sheave 43. The oil passage 182A is communicated at a predetermined position of the oil passage 180 and the movable sheave 43, as will be described later.

  Further, an annular groove 195D having a predetermined width is formed on the outer peripheral surface of the cylindrical portion 195B of the annular member 195, and at the same time, the cylindrical portion 195B is adjacent to the annular groove 195D with the seal ring 195C. A drain hole 195E is formed in the radial direction. A drain hole 190E is also formed in the second cylindrical portion 190D of the cylinder member 190 in the same radial direction. As will be described later, the drain holes 190E and 195E communicate with each other via the annular groove 195D when the movable sheave 43 is moved to a large groove width, in other words, when the capacity of the hydraulic chamber PCI on the inner diameter side is small. It is said that.

  A nut 184 is fastened and fixed to the outer periphery of the secondary shaft 31, and the bearing 34 and the cylinder member 190 are sandwiched in the axial direction of the secondary shaft 31 and positioned and fixed by the nut 184 and the step portion 31 </ b> B. Yes. Therefore, it is guaranteed that the opening portion of the oil passage 181 adjacent to the step 31B always communicates with the hydraulic chamber PCI on the inner diameter side.

(4) Configuration of Hydraulic Circuit Next, the hydraulic circuit 200 of the hydraulic control device in the belt type continuously variable transmission 9 will be described with reference to FIG.

  In the present embodiment, the hydraulic oil sucked from the oil tank or oil pan and discharged from the oil pump 20 is supplied to the oil passage 202. The hydraulic oil supplied to the oil passage 202 is provided in the oil passage 204 branched from the oil passage 202, is regulated by a pressure regulating valve 208 that is duty-controlled by a duty solenoid 206, and has a line pressure PL. Supplied to the channel 210. The hydraulic oil having the line pressure PL is made the control hydraulic pressure Pdr by the primary side pressure reducing valve 214 provided in the oil passage 212 branched from the oil passage 210, and includes the first hydraulic chamber PC1 and the second hydraulic chamber PC2. It is supplied to the hydraulic actuator 41 on the primary side. The primary side pressure reducing valve 214 is duty-controlled by a duty solenoid 216 to control the line pressure PL to the control oil pressure Pdr. An orifice 215 is provided in the drain oil passage 213 of the primary pressure reducing valve 214. An oil passage 217 branched from the drain oil passage 213 upstream of the orifice 215 and connected to a switching valve 227 described later is provided.

  Further, the hydraulic oil having the line pressure PL is controlled by the secondary pressure reducing valve 220 provided in the oil passage 210 to be the control hydraulic pressure Pdn, and is supplied to the secondary hydraulic actuator 45. The secondary pressure reducing valve 220 is duty-controlled by a duty solenoid 222 to control the line pressure PL to the control oil pressure Pdn. In this embodiment, the hydraulic oil whose pressure is controlled to be reduced to the control hydraulic pressure Pdn is the outer diameter of the secondary hydraulic actuator 45 described above via the switching valve 224 provided in the oil passage 210 downstream from the secondary pressure reducing valve 220. It is supplied to the side hydraulic chamber PCO. On the other hand, the hydraulic oil whose pressure is controlled to be reduced to the control hydraulic pressure Pdn described above is also applied to the secondary hydraulic actuator 45 via an oil passage 228 branched from the oil passage 210 downstream of the secondary pressure reduction valve 220 and upstream of the switching valve 224. Supplied to the inner diameter side hydraulic chamber PCI. Note that the switching valve 224 is switched by the solenoid valve 226 with the driving source pressure being controlled on / off.

  Further, the oil passage 217 branched from the drain oil passage 213 of the primary-side pressure reducing valve 214 is joined to the oil passage 210 downstream of the switching valve 224 and downstream of the secondary-side pressure reducing valve 220. The oil passage 217 is provided with the switching valve 227 described above upstream from the junction with the oil passage 210. Note that the switching valve 227 is switched by the solenoid valve 229 with the driving source pressure being controlled on / off in the same manner as the switching valve 224 described above.

  Here, reference numeral 230 denotes a pressure reducing valve, which is provided in the oil passage 232 branched from the oil passage 210 having the line pressure PL, and is supplied to the above-described duty solenoids 206, 216 and 222, the solenoid valve 226 and the solenoid valve 229. The above-mentioned original pressure (constant) Psol (for example, 0.5 MPa) is formed.

  Reference numeral 240 denotes a controller that controls the entire vehicle, and includes an arithmetic processing unit (CPU or MPU), a storage unit (RAM and ROM), and a microcomputer mainly including an input / output interface.

  For this controller 240, various parameters indicating the operating state of the engine 1, for example, engine rotation speed, accelerator opening, throttle opening sensor signal, various parameters indicating the state of the transaxle 3, for example, Information such as the torque ratio of the torque converter 7, the rotational speed Nin of the input shaft 30 and the rotational speed Nout of the output shaft 31, and the vehicle speed V are input as signals of various sensors and calculation results, and obtained in advance through experiments or the like. The above-described duty solenoids 206, 216 and 222 and the solenoid valve 226 are controlled to obtain the required gear ratio γ (= Nin / Nout) and the belt clamping pressure based on the map and the like, and the above-described control hydraulic pressure Pdr and control A hydraulic pressure Pdn is formed.

  Further, the controller 240 also stores data for performing shift control of the engine 1, the lockup clutch 19, and the belt type continuously variable transmission 9 based on various signals. For example, by controlling the gear ratio of the belt-type continuously variable transmission 9 based on the traveling state such as the accelerator opening and the vehicle speed, data for selecting the optimum operating state of the engine 1 or the accelerator opening A lockup clutch control map using the speed and the vehicle speed as parameters is stored in the controller 240, and the lockup clutch 19 is controlled to each of engagement / release / slip states based on the lockup clutch control map. Based on various signals input to the controller 240 and data stored in the controller 240, control signals are output from the controller 240 to the fuel injection control device, the ignition timing control device, and the hydraulic control device. The

(5) Control / Operation The belt-type continuously variable transmission 9 has conditions such as data stored in the controller 240 (for example, an optimum fuel consumption curve with engine speed and throttle opening as parameters), vehicle speed, and accelerator opening. The gear ratio and the clamping pressure are controlled so that the operating state of the engine 1 becomes the optimum state based on the vehicle acceleration request determined from the above. Specifically, the width of the groove 40 of the primary pulley 36 is adjusted by controlling the hydraulic pressure in the hydraulic chamber of the hydraulic actuator 41. As a result, the winding radius of the belt 46 in the primary pulley 36 changes, and the ratio between the input rotation speed and the output rotation speed of the belt-type continuously variable transmission 9, that is, the gear ratio is controlled steplessly (continuously). .

  Further, the width of the groove 44 of the secondary pulley 37 changes by controlling the oil pressure of the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI of the hydraulic actuator 45. That is, the clamping force (in other words, thrust) in the axial direction of the secondary pulley 37 with respect to the belt 46 is controlled. The tension of the belt 46 is controlled by this clamping pressure, and the contact surface pressure between the primary pulley 36 and the secondary pulley 37 and the belt 46 is controlled. The oil pressure in the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI is controlled based on the torque input to the belt type continuously variable transmission 9, the gear ratio of the belt type continuously variable transmission 9, and the like. The torque input to the belt type continuously variable transmission 9 is determined based on the engine speed, the throttle opening, the torque ratio of the torque converter 7, and the like.

  Here, the control and operation of the primary pulley 36 and the hydraulic actuator 41 of the belt type continuously variable transmission 9 will be specifically described. When the hydraulic pressures of the first hydraulic chamber PC1 and the second hydraulic chamber PC2 are drained through the oil passages 116 and 110, the movable sheave 39 and the piston 131 are provided with bearings due to the tension applied to the belt 46. It is pressed to the 33 side. This state is shown above the axis A1 in FIG. In this state, since the movable sheave 39 is located at the outer peripheral side opening of the oil passage 109, the oil passage 109 and the second hydraulic chamber PC2 are shut off.

  From the above state, the control hydraulic pressure Pdr is supplied from the oil passage 212 of the hydraulic circuit 200 to the first hydraulic chamber PC1 and the second hydraulic chamber PC2 via the oil passage 110, and the first hydraulic chamber PC1. When the hydraulic pressure in the second hydraulic chamber PC2 rises, the hydraulic pressure in the first hydraulic chamber PC1 is directly transmitted to the movable sheave 39, and the hydraulic pressure in the second hydraulic chamber PC2 is transferred to the movable sheave 39 via the piston 131. Then, the movable sheave 39 is pressed in the axial direction toward the fixed sheave 38 side. When the oil passage 109 is opened by the movement of the movable sheave 39, the oil pressure is supplied to the first hydraulic chamber PC1 and the second hydraulic chamber PC2 through the oil passage 109. In this way, the width of the groove 40 of the primary pulley 36 is reduced.

  The width of the groove 40 is controlled based on the tension applied to the belt 46 and the pressing force based on the hydraulic pressure of the first hydraulic chamber PC1 and the second hydraulic chamber PC2. The state shown below the axis A1 in FIG. 2A corresponds to a state where the width of the groove 40 is the narrowest. When the piston 131 moves toward the fixed sheave 38, the air in the air chamber 136 is discharged to the outside of the air chamber 136 through the air passage 137, while the piston 131 is directed toward the bearing 33. When moving, since the air outside the air chamber 136 enters the air chamber 136 via the air passage 137, the piston 131 moves smoothly.

  By the way, the piston 131 is positioned in the radial direction by the O ring 131 </ b> A contacting the cylindrical portion 117 </ b> B of the partition wall 117 and the resin seal ring 131 </ b> B contacting the cylindrical portion 126 </ b> B of the cylinder member 126. The contact length in the axial direction between the cylindrical portion 117B of the partition wall 117 and the inner peripheral surface of the piston 131 is designed to be as long as possible by the sleeve 131C.

Next, the control and operation of the secondary pulley 37 and the hydraulic actuator 45 of the belt type continuously variable transmission 9 will be specifically described. When the hydraulic pressure in the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI is discharged through the drain hole or the oil passage, the movable sheave 43 is pressed toward the bearing 34 by the tension applied to the belt 46. Has been. This state is shown in FIG.
It is shown above the axis B1 of (B). In this state, the oil passage 181 and the inner diameter side hydraulic chamber PCI communicate with each other, but the movable sheave 43 is located at the outer peripheral side opening of the oil passage 180, so the oil passage 180 and the outer diameter side hydraulic pressure are located. The room PCO is shut off.

  From the above state, when the control oil pressure Pdn is supplied from the oil passage 228 of the hydraulic circuit 200 to the inner diameter side hydraulic chamber PCI via the oil passage 181, and the oil pressure in the inner diameter side hydraulic chamber PCI is increased, the inner diameter side hydraulic pressure is increased. The control pressure Pdn of the chamber PCI is directly transmitted to the end surface of the cylindrical portion 182 of the movable sheave 43, and the movable sheave 43 is pressed in the axial direction toward the fixed sheave 42 side. When the oil passage 180 is opened by the movement of the movable sheave 43, the control oil pressure Pdn is also supplied to the outer diameter side hydraulic chamber PCO via the oil passages 180 and 182A. In this way, as will be described in detail later, the communication and blocking of the oil passages 180 and 182A as the pressure oil supply holes are controlled at the position corresponding to the predetermined gear ratio when the movable sheave 43 moves. The width of the groove 44 of the secondary pulley 37 is narrowed. The width of the groove 44 is controlled based on the tension applied to the belt 46 and the pressing force based on the control oil pressure Pdn of the inner diameter side hydraulic chamber PCI and the outer diameter side hydraulic chamber PCO. The state shown below the axis B1 in FIG. 2B corresponds to a state in which the width of the groove 44 is the narrowest and the gear ratio is large.

  Here, when the movable sheave 43 moves from the state shown below the axis B1 in FIG. 2B where the width of the groove 44 is the narrowest and the gear ratio is large, to the side where the gear ratio is small. The manner in which the control hydraulic pressure Pdn is switched and supplied and the positional relationship between the pressure oil supply hole and the drain hole will be described. In the state where the gear ratio is large, the oil passage 182A formed in the radial direction in the cylindrical portion 182 of the movable sheave 43 as the pressure oil supply hole and the oil passage 178 in the secondary shaft 31 are formed in the radial direction. The oil passage 180 opens to the outside, and the outer diameter side hydraulic chamber PCO communicates with the oil passage 210 of the hydraulic circuit 200. On the other hand, as a drain hole, a radial drain hole 195E formed in the cylindrical portion 195B of the annular member 195, and an adjacent annular groove 195D and a radial direction formed in the second cylindrical portion 190D of the cylinder member 190 are provided. The position is relatively shifted from the drain hole 190E, and they are closed to each other. From this state, when the movable sheave 43 moves toward the side with a smaller gear ratio, the opening state of the oil passage 182A and the oil passage 180 shifts to the closed state, and then the drain that has been in the closed state. A hole opens. That is, when the end of the annular groove 195D communicates with the drain hole 190E of the cylinder member 190, it communicates with the drain hole 195E of the annular member 195, and the drain hole is opened.

The positional relationship between the pressure oil supply hole and the drain hole at this time will be further described. In the present embodiment, the pressure oil supply hole is opened from the open state to the closed state at a position where the speed ratio is slightly larger than the predetermined speed ratio γ1. On the other hand, the drain hole is formed so that the gear ratio changes from the closed state to the open state at a predetermined gear ratio γ1. That is, the pressure oil supply hole and the drain hole are formed in such a positional relationship that when the movable sheave 43 moves, the pressure oil supply hole and the drain hole overlap and close together in the vicinity of the predetermined speed ratio γ1. Thus, by forming the pressure oil supply hole and the drain hole so as to overlap and close together, the pressure drop below the control oil pressure Pdn of the outer diameter side hydraulic chamber PCO due to both opening simultaneously. Is preventing.
When the pressure oil supply hole is closed, the hydraulic oil having the control hydraulic pressure Pdn is not supplied to the outer diameter side hydraulic chamber PCO, and the movable sheave 43 is sandwiched only by the control hydraulic pressure Pdn supplied to the inner diameter side hydraulic chamber PCI. Pressure is generated.

  By the way, when a centrifugal force is generated by the rotation of the secondary shaft 31, centrifugal oil pressure acts on both the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI, and the hydraulic pressures of the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI are As a result, the pressing force that presses the movable sheave 43 toward the fixed sheave 42 may be higher than the target value corresponding to the torque to be transmitted. In the present embodiment, as described above, when the rotational speed is smaller than the predetermined speed change ratio γ1 that is likely to exceed a predetermined value, the clamping pressure is generated only by the inner diameter side hydraulic chamber PCI that is less influenced by the centrifugal force. Thus, the influence of centrifugal hydraulic pressure is reduced with a simple configuration.

  In the above-described embodiment, the switching of communication between the two hydraulic chambers of the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI and only the inner diameter side hydraulic chamber PCI is made to correspond to the movement of the movable sheave 43, Although it is configured to be performed by the constituent members forming the respective hydraulic chambers, in addition to this, it is also possible to perform by the hydraulic circuit 200 shown in FIG. That is, switching between the communication between the two hydraulic chambers of the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI and only the inner diameter side hydraulic chamber PCI is performed in the oil path 210 connected to the outer diameter side hydraulic chamber PCO. This is configured to be performed by the valve 224. Specifically, a spool valve is used as the switching valve 224, and a solenoid valve 226 for switching the valve is used to open and close the oil passage 210 connected to the outer diameter side hydraulic chamber PCO. Thus, when an operation signal is sent to the solenoid valve 226 in response to a command from the controller 240, the solenoid valve 226 is activated, the original pressure Psol is supplied to the solenoid port of the switching valve 224, and the switching valve 224 is closed. Switched. As a result, the oil passage 210 is blocked and the supply of the control hydraulic pressure Pdn to the outer diameter side hydraulic chamber PCO is stopped.

  In this way, switching of communication between the two hydraulic chambers of the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI and only the inner diameter side hydraulic chamber PCI is provided in the oil passage 210 connected to the outer diameter side hydraulic chamber PCO. By using the switching valve 224, the switching condition can be set with a large degree of freedom. For example, when the rotational speed of the movable sheave is equal to or greater than a predetermined value affected by the centrifugal oil pressure regardless of the primary pulley or the secondary pulley, these are detected by the rotational speed detection means (of the secondary shaft 31). Therefore, the solenoid valve 226 is actuated so that the clamping pressure is generated only by the hydraulic chamber on the inner diameter side.

  By the way, in general, it is the movable sheave 43 on the secondary side that the rotational speed of the movable sheave becomes equal to or greater than the predetermined value affected by the centrifugal hydraulic pressure, and at least the speed ratio γ including the overdrive state is a predetermined value (for example, Since the above-mentioned γ1 = 1.2) is smaller and the vehicle is at a high vehicle speed, the solenoid valve 226 is actuated by the determination of the controller 240 by detecting this state by a predetermined detection means, and the switching valve 224 can be closed and the clamping pressure can be generated only by the inner diameter side hydraulic chamber PCI.

  Next, the control at the time of sudden downshift at the time of sudden acceleration or sudden braking of the vehicle will be described. In the traveling state of a vehicle that requires this sudden downshift, that is, in a traveling state or operating condition with a relatively small gear ratio, the switching valve 224 is closed and only the inner diameter side hydraulic chamber PCI is controlled via the oil passage 228. As described above, the hydraulic pressure is supplied and the clamping pressure is generated. The direction in which the groove width is increased by moving the primary movable sheave 39 away from the fixed sheave 38 so that the gear ratio γ is increased at the time of sudden acceleration request or sudden downshift during sudden braking in such a traveling state. It is necessary to move the secondary sheave 43 toward the fixed sheave 42 side quickly in the direction in which the groove width becomes narrower.

  In the present embodiment, when the controller 240 determines this sudden downshift, the solenoid valve 229 is activated and the switching valve 227 is switched. As a result, the oil passage 217 branched from the drain oil passage 213 of the primary pressure reducing valve 214 is communicated with the outer diameter side hydraulic chamber PCO via the oil passage 210 downstream of the confluence. As a result, the hydraulic oil drained from the first hydraulic chamber PC1 and the second hydraulic chamber PC2 of the primary pulley 36 due to the decrease in the primary-side control hydraulic pressure Pdr is supplied to the outer diameter side hydraulic chamber PCO via the oil passage 217. Supplied. Therefore, in addition to the inner diameter side hydraulic chamber PCI, a large amount of hydraulic oil is quickly supplied to the outer diameter side hydraulic chamber PCO, and centrifugal hydraulic pressure is generated by rotation, whereby the movable sheave 43 acts in the direction of narrowing the groove. Therefore, the movable sheave 43 on the secondary side is quickly moved, and the responsiveness of the sudden downshift is improved.

It is a skeleton figure which shows the transaxle to which the belt type continuously variable transmission of this invention is applied. It is sectional drawing which shows one Embodiment of the belt type continuously variable transmission of this invention, (A) has shown the structure of the primary pulley, (B) has shown one structure of the secondary pulley. It is a hydraulic circuit diagram of an embodiment of the present invention.

Explanation of symbols

30 Primary shaft 31 Secondary shaft 36 Primary pulley 37 Secondary pulley 38 Primary side fixed sheave 39 Primary side movable sheave 42 Secondary side fixed sheave 43 Secondary side movable sheave 178, 179, 180, 181 Oil passage 182A Oil passage (pressure oil supply hole)
190 cylinder member 190E drain hole 195 annular member 195C drain hole 195D annular groove 200 hydraulic circuit 224, 227 switching valve PCO outer diameter side hydraulic chamber PCI inner diameter side hydraulic chamber

Claims (2)

A belt-type continuously variable motor comprising at least one shift control hydraulic chamber for changing the groove width of the primary pulley and two hydraulic chambers for generating a tension control belt clamping pressure acting on the secondary movable sheave. In the hydraulic control device of the transmission,
When a predetermined operating condition is satisfied, the hydraulic oil is drained from one of the two hydraulic chambers on the secondary side, and at the time of a sudden downshift in the predetermined operating condition, the primary side shift control hydraulic pressure A hydraulic control device for a vehicular belt type continuously variable transmission, characterized in that hydraulic oil is supplied from a chamber to the one hydraulic chamber. The two secondary-side hydraulic chambers are an outer-diameter-side hydraulic chamber and an inner-diameter-side hydraulic chamber, and the one hydraulic chamber into which the hydraulic oil is drained is an outer-diameter-side hydraulic chamber. The hydraulic control device for a belt type continuously variable transmission for a vehicle according to claim 1.

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