JP2005090719A - Belt-type continuously variable transmission for vehicles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt-type continuously variable transmission for vehicles capable of scaling down the influence of centrifugal hydraulic pressure with a simple structure without requiring a structure for generating hydraulic pressure for compensation or centrifugal hydraulic pressure. <P>SOLUTION: The continuously variable transmission is provided with at least two hydraulic pressure chambers independently; an outer diameter side hydraulic pressure chamber PCO and an inner diameter side hydraulic pressure chamber PCI which generate a belt pinching force which affects a movable sheave 43 and, when the number of revolutions of the movable sheave 43 is more than a predetermined value, the pinching force is so designed as to be generated only by the hydraulic pressure chamber PCI in the inner diameter side. In the description of the preferred embodiment, model changes between the two hydraulic chambers and only the inner diameter side hydraulic chamber are conducted through a hydraulic supply hole and a drain hole formed in a secondary shaft 31 which is a constituting member for forming each hydraulic pressure chamber, a cylinder member 190, and an annular member 195 in compliance with the movement of the movable sheave 43. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a belt-type continuously variable transmission for a vehicle, and in particular, transmits power between two variable pulleys by a belt, and controls a transmission ratio thereof by changing a belt winding radius. The present invention relates to a belt type continuously variable transmission for a vehicle.

  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 belt-type continuously variable transmission described in Patent Document 1, the centrifugal hydraulic pressure acts on the first hydraulic chamber during the hydraulic control of the first hydraulic chamber, and the hydraulic pressure in the first hydraulic chamber is increased. When the hydraulic pressure is higher than the target hydraulic pressure, a hydraulic pressure corresponding to the centrifugal hydraulic pressure is generated in the second hydraulic pressure chamber to cancel out the portion corresponding to the centrifugal hydraulic pressure.

  Further, in the centrifugal pressure compensator in the belt-type continuously variable transmission described in Patent Document 2, the centrifugal hydraulic pressure compensation force is generated by another piston / cylinder assembly formed radially outward, thereby causing centrifugal The hydraulic equivalent is offset.

  However, the belt-type continuously variable transmissions described in Patent Documents 1 and 2 are configured to cancel the amount corresponding to the centrifugal hydraulic pressure in any case, so that the hydraulic pressure for cancellation and the centrifugal hydraulic pressure are generated. Since the configuration is required, the configuration is complicated accordingly, and there is a problem that the size must be increased.

  The present invention has been made against the background of the above circumstances, and it is possible to reduce the influence of centrifugal hydraulic pressure with a simple configuration without requiring a configuration for generating canceling hydraulic pressure or centrifugal hydraulic pressure. It is intended to provide a belt type continuously variable transmission.

  In order to achieve the above object, a belt type continuously variable transmission for a vehicle according to an aspect of the present invention includes at least two hydraulic chambers, an outer diameter side and an inner diameter side, which generate a belt clamping pressure acting on a movable sheave. It is provided independently, and when the rotational speed of the movable sheave is equal to or greater than a predetermined value, the clamping pressure is generated only by the hydraulic chamber on the inner diameter side.

  Here, the movable sheave is a secondary-side movable sheave, and is configured so that the clamping pressure is generated only by the inner diameter-side hydraulic chamber at least when the speed ratio is smaller than a predetermined value and the vehicle has a high vehicle speed. It is preferable to do.

  Further, switching between the two outer pressure chambers on the outer diameter side and the inner diameter side and only the hydraulic chamber on the inner diameter side is performed by the constituent members forming the respective hydraulic chambers in correspondence with the movement of the movable sheave. You may comprise as follows.

Here, when the movable sheave moves, the pressure oil supply hole and the drain hole formed in the constituent members forming the outer diameter side hydraulic chamber are overlapped and closed in the vicinity of a predetermined gear ratio. It is preferably formed in a positional relationship.
The switching between the two hydraulic chambers on the outer diameter side and the inner diameter side and only the hydraulic chamber on the inner diameter side is performed by a switching valve provided in an oil passage connected to the outer diameter side hydraulic chamber. May be.

Furthermore, it is preferable that the clamping pressure is generated only by the inner diameter side hydraulic chamber even during a sudden downshift.
Moreover, it is preferable that the said switching valve is comprised so that the oil path connected to the said outer diameter side hydraulic chamber may be opened at the time of a failure.

  In addition, at the time of the failure, the determination may be made based on a detection value by means for detecting the pressure in the primary hydraulic chamber.

  According to one aspect of the present invention, at least two hydraulic chambers of an outer diameter side and an inner diameter side that generate belt clamping pressure acting on the movable sheave are independently provided, and the rotational speed of the movable sheave is a predetermined value or more. At this time, since the clamping pressure is generated only by the hydraulic chamber on the inner diameter side, when the rotational speed is a predetermined value or more where the influence of the centrifugal force is large, the generated centrifugal force is small and the centrifugal hydraulic pressure is low. The clamping pressure is generated only by the hydraulic chamber on the inner diameter side which has little influence. Therefore, it is possible to reduce the influence of the centrifugal hydraulic pressure with a simple configuration without requiring a special configuration for generating the offset hydraulic pressure and the centrifugal hydraulic pressure.

  Here, the movable sheave is a secondary-side movable sheave, and at least the gear ratio is smaller than a predetermined value, and the clamping pressure is generated only by the inner-diameter hydraulic chamber at a high vehicle speed. Then, the influence of the centrifugal hydraulic pressure can be reduced at the high speed of the secondary pulley that is most susceptible to the centrifugal hydraulic pressure.

  Further, switching between the two outer pressure chambers on the outer diameter side and the inner diameter side and only the hydraulic chamber on the inner diameter side is performed by the constituent members forming the respective hydraulic chambers in correspondence with the movement of the movable sheave. According to the structure made in this way, it can be simplified without providing special parts.

Further, the pressure oil supply hole and the drain hole formed in the constituent members forming the outer diameter side hydraulic chamber are positions where they are overlapped and closed in the vicinity of a predetermined gear ratio when the movable sheave moves. According to the structure formed in the relationship, it can be simplified without providing special parts.
The switching between the two hydraulic chambers on the outer diameter side and the inner diameter side and only the hydraulic chamber on the inner diameter side is performed by a switching valve provided in an oil passage connected to the outer diameter side hydraulic chamber. This increases the degree of freedom of control.

  Further, even during a sudden downshift, if the clamping pressure is generated only by the hydraulic chamber on the inner diameter side, the amount of oil required to move the movable sheave on the secondary side can be reduced. The theoretical discharge amount can be reduced.

  Further, when the switching valve is configured to open an oil passage connected to the outer diameter side hydraulic chamber at the time of failure, an oil passage to the outer diameter side hydraulic chamber is secured even at the time of failure.

  Note that if the failure is determined based on the detection value by the means for detecting the pressure in the primary hydraulic chamber, it can be easily determined without providing a special sensor.

Here, an embodiment 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 driven 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 driven gear 47 of the belt type continuously variable transmission 9 and the final reduction gear 10. Yes. 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) One Configuration Example 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 each groove 182B and each groove 31C have the same phase in the circumferential direction, and straddle both grooves. A plurality of balls (not shown) are arranged. The secondary shaft 31 and the movable sheave 43 can be smoothly moved relative to each other in the axial direction by the grooves and the balls, but cannot be relatively moved 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. Further, the second cylindrical portion 190D of the cylinder member 190 is similarly formed with a drain hole 190E in the 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 described above 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. The oil passage 212 is provided with a hydraulic sensor 218 between the primary hydraulic actuator 41 and the primary pressure reducing valve 214.

  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, in the downstream of the secondary side pressure reducing valve 220 and upstream of the switching valve 224, the hydraulic oil pressure-reduced from the oil passage 210 to the control hydraulic pressure Pdn described above is similarly supplied to the secondary side hydraulic actuator 45 via the branched oil passage 228. 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.

  Here, 230 is 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 and the solenoid valve 226. (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, in addition to the signal from the hydraulic sensor 218 described above, various parameters indicating the operating state of the engine 1, such as the engine speed, accelerator opening, throttle opening sensor signal, Various parameters representing the state of the axle 3, 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 also included in various sensors and calculation results. In order to obtain a required gear ratio γ (= Nin / Nout) and a belt clamping pressure based on a map or the like that is input as a signal and obtained in advance through experiments or the like, the above-described duty solenoids 206, 216, and 222 and the solenoid valve are used. 226 is controlled, the control oil pressure Pdr and the control oil described above 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 includes data stored in the controller 240 (for example, an optimal fuel consumption curve using the engine speed Ne and the throttle opening as parameters), the vehicle speed V, and the accelerator opening Θ. 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 acceleration request of the vehicle determined from the conditions such as 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 in the first hydraulic chamber PC1 and the second hydraulic chamber PC2 are discharged through the oil passages 116 and 110, the movable sheave 39 and the piston 131 are in 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 O-ring 133 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. That is, the axial length of the surface of the piston 131 parallel to the cylindrical portion 117B of the partition wall 117 can be secured as long as possible. As a result, the intersection between the central axis (not shown) of the piston 131 and the central axis (not shown) of the partition wall 17 is suppressed.

  Therefore, when the piston 131 moves in the axial direction, particularly when the piston 131 moves in the axial direction due to a sudden change in the oil pressure of the first hydraulic chamber PC1 and the second hydraulic chamber PC2, An increase in sliding resistance (friction resistance) between the outer cylindrical portion 126 of the cylinder 136 and the cylindrical portion 117B of the partition wall 117 is suppressed, and the operation responsiveness of the piston 131 can be maintained well.

  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 above the axis B1 in FIG. 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 primary 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, the radial drain hole 195E formed in the cylindrical portion 195B of the annular member 195, and the radial groove formed in the adjacent cylindrical groove 195D and the second cylindrical portion 190D of the cylinder member 190 are arranged. The position is relatively shifted from the drain hole 190E, and they are closed. From this state, when the movable sheave 43 moves toward the side where the gear ratio is small, 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, the end of the annular groove 195D 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 with reference to FIG. 6. In the present embodiment, the pressure oil supply hole is located at a position where the speed ratio γ is slightly larger than 1.2, for example. In contrast to the transition from the open state to the closed state, the drain hole is formed so as to transition from the closed state to the open state at a gear ratio γ of 1.2. 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 a predetermined gear ratio of 1.2. In this way, by forming the pressure oil supply hole and the drain hole so as to overlap and close together, the pressure drops below the control oil pressure Pdn of the outer diameter side hydraulic chamber PCO due to the simultaneous opening of both. 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 a predetermined speed change ratio 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 centrifugal force. By doing so, 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. This configuration will be described with reference to FIGS. 5A and 5B showing a part of the hydraulic circuit 200 of FIG.

  In the example shown in FIG. 5A, a solenoid valve 226 (N / C) is used by using a spool valve as the switching valve 224 and a normally closed solenoid valve 226 (N / C) as a solenoid valve for switching it. The oil passage 210 connected to the outer diameter side hydraulic chamber PCO is opened during the failure. In FIG. 5A, the closed state is shown above the axis of the switching valve 224, and the open state is shown below. Accordingly, when an operation signal is sent to the normally closed solenoid valve 226 (N / C) in accordance with a command from the controller 240, the solenoid valve 226 (N / C) is activated, and the source pressure Psol is changed to the solenoid of the switching valve 224. The switching valve 224 is switched to the closed state. 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.

  On the other hand, in the example shown in FIG. 5B, a spool valve is similarly used as the switching valve 224, and a normally open solenoid valve 226 (N / O) is used as a solenoid valve for switching the solenoid valve 226 (N / O). N / O) is configured to open the oil passage 210 connected to the outer diameter side hydraulic chamber PCO at the time of failure. In FIG. 5B, the closed state is shown above the axis of the switching valve 224, and the open state is shown below. Therefore, when an operation signal is sent to the normally open solenoid valve 226 (N / O) according to a command from the controller 240, the solenoid valve 226 (N / O) is closed and the switching valve 224 of the original pressure Psol is closed. Supply to the solenoid port is stopped, and the switching valve 224 is switched to the closed state. 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 it is smaller than the above-mentioned 1.2) 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 is turned on. It is possible to close and generate the clamping pressure only by the inner diameter side hydraulic chamber PCI.

  Furthermore, the switching valve 224 may be closed even during a sudden downshift, as shown in FIG. That is, at the time of sudden acceleration request or sudden downshift at the time of sudden braking, the movable sheave 43 on the secondary side is moved toward the fixed sheave 42 side in the direction of narrowing the groove so that the gear ratio γ is increased. It is necessary. In this case, if the groove width is narrowed only by the inner diameter side hydraulic chamber PCI, that is, if the holding pressure is generated, the amount of oil required to move the movable sheave 43 on the secondary side can be reduced. The theoretical discharge amount of 20 can be reduced. Therefore, in the present embodiment, when the controller 240 determines that the sudden downshift is being performed, when the speed ratio γ is greater than a predetermined value (for example, 1.2 described above), the solenoid valve 226 is operated to The clamping pressure is generated only by the hydraulic chamber PCI.

(6) Other Configuration Examples of Secondary Pulley By the way, as described above, 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 performed by changing the outer diameter. Since this can be performed by the switching valve 224 provided in the oil passage 210 connected to the side hydraulic chamber PCO, this switching corresponds to the movement of the movable sheave 43 as shown in FIG. Thus, the present invention is not limited to a configuration in which each hydraulic chamber is formed by a component member. Therefore, another configuration example of the secondary pulley 37 capable of supplying hydraulic oil to the two hydraulic chambers of the outer-diameter side hydraulic chamber PCO and the inner-diameter side hydraulic chamber PCI regardless of the moving position of the movable sheave 43 will be described with reference to FIG. I will explain.

  FIG. 3B is a cross-sectional view showing another configuration example of the secondary pulley 37. Since the basic configuration of the secondary pulley 37 is the same as that of the secondary pulley 37 described above, the same portions are denoted by the same reference numerals to avoid redundant description, and the differences will be described. The primary pulley 36 is the same as that shown in FIG. The oil passage 180 provided in communication with an oil passage 178 formed inside the secondary shaft 31 and extended in the radial direction toward the outer peripheral surface of the secondary shaft 31 has a predetermined width on the outer peripheral surface of the secondary shaft 31. The annular groove 180A is formed and opened.

  The movable sheave 43 of the secondary pulley 37 includes a 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, which is the same as the above-described configuration example. However, instead of the oil passage 182A formed in the radial direction in the cylindrical portion 182 of the movable sheave 43, the oil passage 182C communicated with the annular groove 180A in which the oil passage 180 is opened regardless of the moving position of the movable sheave 43 is inclined. Is provided.

  An annular cylinder member 191 is provided between the step portion 31 </ b> B and the bearing 34. The cylinder member 191 includes a first radial direction portion 191A, a cylindrical portion 191B extending from the outer peripheral end of the first radial direction portion 191A toward the radial direction portion 183 of the movable sheave 43, and an end portion of the cylindrical portion 190B. And a second radial portion 191 </ b> C that extends in the radial direction while being curved outward.

  On the other hand, the movable sheave 43 is provided with an annular member 196. The annular member 196 has a radial direction portion 196A fixed to the radial direction portion 183 of the movable sheave 43 and a cylindrical portion 196B extended from the outer peripheral end toward the cylinder member 191 side. Here, a resin-made seal ring 191D is attached to the outer peripheral end of the second radial portion 191C, and is in contact with the inner peripheral surface of the cylindrical portion 196B of the annular member 196 in a state of being relatively movable in the axial direction. In addition, a seal surface is formed at the contact portion.

  The outer peripheral surface of the cylindrical portion 182 of the movable sheave 43 and the inner peripheral surface of the cylindrical portion 191B of the cylinder member 191 are fitted so as to be relatively movable, and the end surface of the cylindrical portion 182 and the outer peripheral surfaces of the cylinder member 191 and the secondary shaft 31 are fitted. A hydraulic chamber PCI on the inner diameter side is formed in a space surrounded by. The inner diameter side hydraulic chamber PCI communicates with the oil passage 181.

  On the other hand, a hydraulic chamber PCO on the outer diameter side is formed in a space surrounded by the outer peripheral surface of the cylindrical portion 182 of the movable sheave 43, the annular member 196, and the cylinder member 191. The outer diameter side hydraulic chamber PCO communicates with the oil passage 182 </ b> C formed to be inclined in the cylindrical portion 182 of the movable sheave 43. Further, a drain hole 191E is formed in a radial direction in a boundary region between the cylindrical portion 191B and the radial direction portion 191C of the cylinder member 191. As will be described later, this drain hole 191E communicates with the outer diameter side hydraulic chamber PCO when the movable sheave 43 is moved to a larger groove width, in other words, when the capacity of the inner diameter side hydraulic chamber PCI is small. It is considered as a position.

  In the embodiment using another configuration example of the secondary pulley 37, the outer diameter side hydraulic chamber PCO is always in communication with the oil passage 210 of the hydraulic circuit 200 in FIG. 4 regardless of the position of the movable sheave 43. 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 switched only by the communication or blocking of the oil passage 210 by the switching valve 224 described above. become. In the other configuration example of the secondary pulley 37, the members constituting the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI are simplified, and an effect of suppressing an increase in weight and an increase in the mounting space is obtained. ing.

  The shift control is performed by hydraulic control of one of the primary and secondary pulleys, and the clamping pressure control is performed by hydraulic control of the other pulley. Generally, the shift control is performed by the primary pulley located on the power source side. 36 is used, and the secondary pulley 37 located on the drive wheel side is used for the clamping pressure control. In this case, since it is necessary to control the hydraulic pressure of the secondary pulley 37 so that the hydraulic pressure of the primary pulley 36 becomes the hydraulic pressure necessary for belt clamping in the driven state, for example, a predetermined axial thrust (clamping pressure) ratio However, since it is difficult to set the axial thrust ratio with high accuracy, a safety factor that takes into account variations in the axial thrust ratio is used. In a belt-type continuously variable transmission, it is known that the relationship between a transmission gear ratio and a shaft thrust force ratio is uniquely determined when the above-described safety factor is determined (see JP-A-6-117530). In the embodiment of the present invention, the actuator of the secondary pulley 37 has an outer-diameter side hydraulic chamber PCO and an inner-diameter side hydraulic chamber PCI. Therefore, when it is desired to set a predetermined gear ratio, a primary side shaft thrust is generated using a predetermined shaft thrust ratio by determining a safety factor for the secondary side shaft thrust. You can do that.

  By the way, when the switching mechanism for controlling the supply of the control hydraulic pressure Pdn to the outer diameter side hydraulic chamber PCO fails (for example, the supply of the control hydraulic pressure Pdn is stopped due to a failure of either the solenoid valve 226 or the switching valve 224). When the supply is continued), the clamping pressure (axial thrust) should be generated only by the inner diameter side hydraulic chamber PCI, but the clamping pressure is also generated by the outer diameter side hydraulic chamber PCO. Become. As a result, the axial thrust on the secondary side becomes larger than the axial thrust required in the system, and the required axial thrust on the primary side becomes excessive. Therefore, the primary actuator 41 also requires a large hydraulic pressure to obtain an excessive axial thrust, and if this state continues, the fuel consumption deteriorates and the durability of the belt is adversely affected.

  Therefore, in the present embodiment, the presence or absence of this fail state is determined by the detected value by the hydraulic sensor 218 provided in the oil passage 212 between the primary hydraulic actuator 41 and the primary pressure reducing valve 214 and the necessary hydraulic value in the system. Based on the above, it can be determined by comparing these. Alternatively, the determination can also be made by calculating the primary thrust from the signal of the duty solenoid 216 that controls the primary pressure reducing valve 214 without a sensor, and comparing the gear ratio, the thrust ratio, and the safety factor. Accordingly, when it is determined that a failure has occurred, the controller 240 shifts to the fail operation mode and at the same time notifies the driver of the fail operation mode with a warning light or the like.

  In the fail operation mode, as described above, when the hydraulic pressure of the primary side hydraulic actuator 41 is excessive, the control hydraulic pressure Pdn applied to both the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI is reduced. As described above, the duty solenoid 206 is controlled to ensure the durability of the belt without applying a load to the belt 46. On the other hand, contrary to the above-described state, the switching mechanism fails and supplies only to the inner diameter side hydraulic chamber PCI, although it is desired to supply the hydraulic pressure to both the outer diameter side hydraulic chamber PCO and the inner diameter side hydraulic chamber PCI on the system. As a result, when the axial thrust on the secondary side is lower than the axial thrust required in the system, the belt clamping pressure decreases. As a result, slip occurs and deteriorates the durability of the belt, so that the duty solenoid 206 is controlled, the control hydraulic pressure Pdn is increased, and the belt clamping pressure is secured. In this case, it is determined that only the inner diameter side hydraulic chamber PCI is used.

  As described above, when the determination is made based on the detection value by the hydraulic pressure sensor 218 as a means for detecting the pressure of the primary side hydraulic chamber or the duty solenoid 216 that controls the primary side pressure reducing valve 214, the fail state of the switching mechanism Can be easily determined without providing a special sensor.

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 sectional drawing which shows other embodiment of the belt type continuously variable transmission of this invention, (A) has shown the structure of the primary pulley, (B) has shown the other structure of the secondary pulley. It is a hydraulic circuit diagram of an embodiment of the present invention. 4 shows a part of the switching mechanism of the hydraulic circuit in FIG. 4, where (A) is an example of a normally closed solenoid valve and a switching valve, and (B) is an example of a normally open solenoid valve and a switching valve. It is a graph for demonstrating the positional relationship of the pressure supply hole and drain hole which concern on embodiment of this invention. It is a graph for demonstrating the relationship at the time of the sudden downshift which concerns on embodiment of this 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 180A Annular groove 182A, 182C Oil passage ( Pressure oil supply hole)
190, 191 Cylinder member 190E Drain hole 191E Drain hole 195, 196 Annular member 195C Drain hole 195D Annular groove 200 Hydraulic circuit 224 Switching valve PCO Outer diameter side hydraulic chamber PCI Inner diameter side hydraulic chamber

Claims (8)

  Independently including at least two hydraulic chambers of an outer diameter side and an inner diameter side for generating a belt clamping pressure acting on the movable sheave, and when the rotational speed of the movable sheave is equal to or greater than a predetermined value, the hydraulic chamber on the inner diameter side A belt type continuously variable transmission for a vehicle, characterized in that the clamping pressure is generated only by the above.   The movable sheave is a secondary-side movable sheave, and is configured to generate the clamping pressure only by the inner diameter side hydraulic chamber at least when the speed ratio is smaller than a predetermined value and the vehicle has a high vehicle speed. The belt type continuously variable transmission for a vehicle according to claim 1.   Switching between the two hydraulic chambers on the outer diameter side and the inner diameter side and only the hydraulic chamber on the inner diameter side is performed by a component member that forms each hydraulic chamber corresponding to the movement of the movable sheave. The belt-type continuously variable transmission for a vehicle according to claim 1 or 2, characterized in that it is configured.   The pressure oil supply hole and the drain hole formed in the constituent members forming the outer diameter side hydraulic chamber are in a positional relationship that overlaps and closes in the vicinity of a predetermined gear ratio when the movable sheave moves. The belt-type continuously variable transmission for a vehicle according to claim 3, wherein the belt-type continuously variable transmission is formed.   Switching between the two hydraulic chambers on the outer diameter side and the inner diameter side and only the hydraulic chamber on the inner diameter side is performed by a switching valve provided in an oil passage connected to the outer diameter side hydraulic chamber. The belt type continuously variable transmission for a vehicle according to any one of claims 1 to 4.   The vehicular belt type device according to any one of claims 1 to 5, wherein the holding pressure is generated only by the inner diameter side hydraulic chamber even during a sudden downshift. Step transmission.   The belt type continuously variable transmission for a vehicle according to claim 5 or 6, wherein the switching valve is configured to open an oil passage connected to the outer diameter side hydraulic chamber at the time of failure. 8. The belt-type continuously variable transmission for a vehicle according to claim 7, wherein at the time of the failure, a determination is made based on a detection value by means for detecting a pressure in the primary hydraulic chamber.

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