JP2018179222A - Vehicular continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a belt type continuously variable transmission for vehicle, capable of suppressing lowering of a service life due to abrasion of a member, which is configured to regulate movement of a movable sheave, to downsize the member, and thereby contributing to downsizing the belt type continuously variable transmission for vehicle.SOLUTION: At a part of a cylindrical portion 102 of a nut 98, an outer peripheral groove 108 is formed, the nut holding a cylinder sheet 100 and a cylinder member 96, which are used for positioning movable sheaves 66b, 70b. Consequently, moment load applied to the nut 98 is reduced to reduce load on a male screw 84 of a sheave shaft 78 and a female screw 104 of the nut 98, and also an area of a bearing surface 106 contacting with the cylinder member 96 can be increased, so that the nut 98 can be downsized, and further a continuously variable transmission 24 can be downsized.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a continuously variable transmission for a vehicle, and relates to a structure capable of suppressing a reduction in life due to wear of a nut that regulates the movement of a movable sheave.

  In a transmission of a vehicle, a fixed sheave integrally formed with a sheave shaft, and a movable sheave splined relative to the sheave shaft so as to be axially movable relative to each other and not rotatable relative to the shaft in a state of facing the fixed sheave And a pair of variable sheaves each having a cylinder member forming an oil pressure chamber for supplying the hydraulic pressure for moving the movable sheave in the axial direction on the end face side of the sheave shaft, and the pair of variable sheaves A continuously variable transmission for a vehicle provided with a transmission belt is well known. In the continuously variable transmission for a vehicle of Patent Document 1, the thrust force of the movable sheave, that is, the force for moving the movable sheave caused by the load transmitted by the transmission belt to the outside in the axial direction of the sheave shaft moves the movable sheave to a predetermined position. By concentrating on a part of the threaded portion of the nut for holding, that is, the end on the movable sheave side, there is a possibility that the durability of the threaded portion formed on the nut and the sheave shaft may be reduced. In order to avoid this, a cutaway portion is provided on the movable sheave side of the nut to reduce the outer diameter of the nut only on the movable sheave side, and the cutaway portion of the nut is configured to receive thrust force generated from the movable sheave. As a result, a thrust force is received at a portion close to the center of the threaded portion of the nut, and the force transmitted from the threaded portion of the nut concentrated at the end of the threaded portion to the threaded portion of the sheave shaft can be dispersed Thus, the decrease in durability of the threads formed on the nut and the sheave shaft is suppressed.

JP, 2010-255700, A

  However, when the outer diameter of a part of the nut is reduced to provide a cut portion, and the thrust force is received at the cut portion, the area receiving the thrust force, that is, the seating surface is reduced. The force transmitted to the variable sheave by the transmission belt is a force which periodically fluctuates between the contact with the transmission belt and each part of the variable sheave, and is prone to wear on the bearing surface of the nut, and the bearing surface By reducing the area of the bearing, there is a risk that the wear of the seat will reduce the life.

  The present invention has been made against the background described above, and an object of the present invention is to suppress wear on a bearing surface of a nut, and to reduce the load applied to the nut. By reducing the size of the nut for restricting the movement of the movable sheave, thereby contributing to the size reduction of the continuously variable transmission for a vehicle.

  According to the first aspect of the present invention, (a) a fixed sheave integrally formed with the sheave shaft and an axially movable relative to the sheave shaft opposite to the fixed sheave in a state opposed to the fixed sheave are not relatively rotatable around the axis A pair of variable sheaves each having a movable sheave spline-fitted to the shaft and a cylinder member forming a hydraulic chamber for supplying the hydraulic pressure for moving the movable sheave in the axial direction to the shaft end of the sheave shaft A transmission belt wound around the pair of variable sheaves, and an external thread formed on the sheave shaft, the thrust force of the movable sheave toward the shaft end of the sheave shaft being the cylinder member; A belt-type continuously variable transmission for a vehicle, comprising: a nut received via the nut; A circumferentially continuous outer peripheral groove is formed in a cylindrical portion between the seat surface and the end surface on the opposite side of the cylinder member in the central axial direction of the nut. It is characterized by

  The nut has a female screw engaged with the male screw and a bearing surface abutting on the cylinder member, and the bearing surface and the end surface on the opposite side of the cylinder member in the central axial direction of the nut By forming a circumferentially continuous outer peripheral groove in the cylindrical portion between them, it is possible to reduce the load moment applied to the nut by the groove bottom diameter of the outer peripheral groove. This makes it possible to suppress the load moment even if the area of the bearing surface, that is, the area of the end face of the movable sheave of the nut that receives the thrust force, is increased. By increasing the area of the seat surface, the pressure per unit area can be reduced, and wear on the contact surface can be suppressed. Further, by adding the groove to the outer peripheral portion of the nut, it is possible to reduce the load moment by the presence of the groove, and it is possible to reduce the load moment received by the female screw of the nut and the male screw of the sheave shaft. For this reason, it is possible to shorten the length in the central axis direction of the female screw of the nut and to reduce the outer diameter, and by reducing the nut, the size and weight of the continuously variable transmission can also be reduced. It becomes possible.

It is a figure explaining a schematic structure of a power transmission path from an engine which constitutes the vehicle to which the present invention is applied to driving wheels. It is a figure explaining the switching of the driving | running | working pattern of the power transmission device in the vehicle of FIG. It is sectional drawing explaining the structure of a pair of movable sheave in the belt type nonproductive transmission of FIG. 1, a fixed sheave, and peripheral parts. It is sectional drawing which expanded and showed the case where a flange nut was used for the nut for fixing of the movable sieve of FIG. It is sectional drawing which expanded and showed the case where a hexagon nut was used for the nut for fixing of the movable sieve of FIG. It is sectional drawing which expanded and showed the case where the nut which provided the outer periphery groove | channel in the said cylindrical part was used for the nut for fixing of the movable sieve of FIG.

  Preferably, the groove bottom diameter of the outer peripheral groove is smaller than the outer diameter of the cylindrical portion of the nut. In this way, the load moment is determined by the groove bottom diameter of the outer peripheral groove, and the load moment received by the nut is reduced. Therefore, it is possible to shorten the axial length of the sheave shaft of the female screw portion of the nut, and by reducing the size of the nut, it is also possible to reduce the size and weight of the continuously variable transmission.

  Preferably, a flange-like portion having a diameter larger than the outer diameter of the other cylindrical portion is provided on a part of the cylindrical portion on the seat surface side of the nut. In this way, it is possible to increase the area of the radial end or bearing surface that receives the thrust force of the movable sheave of the nut, and reduce the wear on the contact surface because the pressure per unit area decreases. Can.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a view for explaining the schematic configuration of a vehicle 10 to which the present invention is applied. In FIG. 1, a vehicle 10 includes an engine 12 such as a gasoline engine or a diesel engine that functions as a drive source for traveling, a drive wheel 14, and a power transmission device 16 provided between the engine 12 and the drive wheel 14. Is equipped. The power transmission device 16 is connected to a torque converter 20 as a fluid type transmission connected to the engine 12, an input shaft 22 connected to the torque converter 20, and an input shaft 22 in a housing 18 as a non-rotational member. A continuously variable transmission is connected to the input shaft 22 through a belt type continuously variable transmission 24 (hereinafter referred to as continuously variable transmission), a forward / backward switching device 26 similarly connected to the input shaft 22, and a forward / backward switching device 26. Gear transmission mechanism 28 as a gear transmission unit provided in parallel with the machine 24, an output shaft 30, a counter shaft 32, an output shaft 30 and a counter shaft which are common output rotary members of the continuously variable transmission 24 and the gear transmission mechanism 28 A reduction gear unit 34 comprising a pair of gears which are provided non-rotatably and meshed with each other, and a differential connected to a gear 36 provided non-rotatably with the counter shaft 32. Ya 38 includes an axle 40 or the like of the pair coupled to a differential gear 38. In the power transmission device 16 configured as described above, the power of the engine 12 (in the case of no distinction is synonymous with torque or force) is the torque converter 20, the continuously variable transmission 24 or the forward / reverse switching device 26, and the gear transmission mechanism 28, the reduction gear device 34, the differential gear 38, the axle 40, and so on sequentially transmit to the pair of drive wheels 14. Further, while the engine 12 is in operation, the output torque of the engine 12 is constantly input to the input shaft 22.

  As described above, the power transmission device 16 is configured to transmit the power of the engine 12 to the drive wheel 14 (here, the drive wheel 14). A gear transmission mechanism 28 as a first transmission unit and a continuously variable transmission 24 as a second transmission unit are provided in parallel with the output shaft 30 which is an output rotating member to output. Therefore, the power transmission device 16 transmits the power of the engine 12 from the first power transmission path PT1 for transmitting the power of the engine 12 from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the gear transmission mechanism 28. A plurality of power transmission paths PT with the second power transmission path PT2 transmitted from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the continuously variable transmission 24 It has prepared in parallel. The power transmission device 16 switches between the first power transmission path PT1 and the second power transmission path PT2 in accordance with the traveling state of the vehicle 10. Therefore, the power transmission device 16 selectively engages the power transmission path PT for transmitting the power of the engine 12 to the drive wheels 14 with the first power transmission path PT1 and the second power transmission path PT2. It has a device. The engagement device includes a first clutch C1 for connecting and disconnecting the first power transmission path PT1 and a second clutch C2 as a second engagement device for connecting and disconnecting the second power transmission path PT2.

  The torque converter 20 is provided coaxially with the input shaft 22 around the input shaft 22 and includes a pump impeller 20p connected to the engine 12 and a turbine impeller 20t connected to the input shaft 22. ing. The pump impeller 20 p is controlled by the hydraulic pressure of the hydraulic pressure for controlling the transmission of the continuously variable transmission 24, operating the plurality of engagement devices, and supplying lubricating oil to each part of the power transmission device 16. A mechanical oil pump 42 generated by being rotationally driven by the motor is connected. During operation of the engine 12, the output torque of the engine 12 is constantly input to the input shaft 22 via the torque converter 20.

  The forward / reverse switching device 26 is provided coaxially with the input shaft 22 around the input shaft 22 in the first power transmission path PT1, that is, on the first axial center RC1, and is a double pinion planetary gear 26p, A first clutch C1 and a first brake B1 are provided. The planetary gear set 26p is a differential mechanism including three rotating elements of a carrier 26c as an input element, a sun gear 26s as an output element, and a ring gear 26r as a reaction element. Carrier 26c is integrally connected to input shaft 22, ring gear 26r is selectively connected to housing 18 via first brake B1, and sun gear 26s is coaxially coaxial with input shaft 22 around input shaft 22. It is connected to a small diameter gear 44 provided rotatably. Further, the carrier 26c and the sun gear 26s are selectively coupled via the first clutch C1. Thus, the first clutch C1 is an engagement device that selectively connects two of the three rotary elements for forward gear travel, and the first brake B1 is for reverse travel. It is an engagement device that selectively connects the ring gear 26r as a reaction force element to the housing 18.

  The gear transmission mechanism 28 includes a small diameter gear 44, and a large diameter gear 48 provided coaxially with the gear mechanism counter shaft 46 so as to be non-rotatable coaxially with the gear mechanism counter shaft 46 and meshing with the small diameter gear 44. ing. The gear transmission mechanism 28 has an idler gear 50 rotatably provided coaxially with the gear mechanism counter shaft 46 around the gear mechanism counter shaft 46 and with respect to the output shaft 30 around the output shaft 30. An output gear 52 coaxially provided so as not to be relatively rotatable and meshing with the idler gear 50 is provided. The output gear 52 has a diameter larger than that of the idler gear 50. Therefore, gear transmission mechanism 28 is a gear transmission mechanism in which one transmission gear ratio (gear position) as a predetermined gear ratio (gear position) is formed in power transmission path PT between input shaft 22 and output shaft 30. It is. Around the gear mechanism counter shaft 46, a mesh type clutch D1 is provided between the large diameter gear 48 and the idler gear 50 to selectively connect and disconnect between them.

  Specifically, the mesh type clutch D 1 is provided with a clutch hub 54 provided non-rotatably coaxially with the gear mechanism counter shaft 46 coaxially with the gear mechanism counter shaft 46, an idler gear 50 and a clutch hub 54. The clutch gear 56 disposed between and fixed to the idler gear 50, and spline engagement (engagement) with the clutch hub 54 prevents relative rotation about the axial center of the gear mechanism counter shaft 46, and And a cylindrical sleeve 58 provided to be relatively movable in a direction parallel to the axis. The sleeve 58, which is always rotated integrally with the clutch hub 54, is moved toward the clutch gear 56 and engaged with the clutch gear 56, whereby the idler gear 50 and the gear mechanism countershaft 46 are connected. The meshed clutch D1 further includes a known synchromesh mechanism S1 as a synchronization mechanism that synchronizes rotation when the sleeve 58 and the clutch gear 56 are fitted. In the meshed clutch D1 configured as described above, the sleeve 58 is the shaft of the gear mechanism countershaft 46 via the shift fork 64 fixed to the fork shaft 60 as the fork shaft 60 is operated by the hydraulic actuator 62. It is slid in a direction parallel to the heart and switched between an engaged state and a released state.

  The first power transmission path PT1 is formed by engagement of the meshed clutch D1 and the first clutch C1 (or first brake B1) provided closer to the input shaft 22 than the meshed clutch D1. . In the power transmission device 16, when the first power transmission path PT1 is formed, it is possible to transmit power of the engine 12 from the input shaft 22 to the output shaft 30 via the gear transmission mechanism 28. Ru. On the other hand, the first power transmission path PT1 is in a neutral state (power transmission) in which power transmission is interrupted when at least the first clutch C1 and the first brake B1 are both released or at least the meshed clutch D1 is released. Shut off).

  The continuously variable transmission 24 is provided on the input shaft 22 which rotates with the engine 12 during operation of the engine 12 which is connected to the engine via the torque converter 20 and the second clutch C2 is released while the vehicle is stopped. A primary sheave (primary pulley) 66 having a variable effective diameter, and a secondary sheave (secondary pulley) 70 provided on a rotary shaft 68 coaxial with the output shaft 30 and having a variable effective diameter, and between the sheaves 66 and 70 Power transmission is performed via the frictional force (belt clamping pressure) between each of the sheaves 66 and 70 and the transmission belt 72. In the primary sheave 66, the sheave hydraulic pressure supplied to the primary sheave 66 (that is, the primary pressure Pin supplied to the hydraulic cylinder 66c) is regulated and controlled by a hydraulic control circuit (not shown), whereby the fixed sheave 66a and the movable sheave 66b The primary thrust Win (= primary pressure Pin × pressure receiving area) for changing the V groove width between is applied. Further, in the secondary sheave 70, the sheave hydraulic pressure supplied to the secondary sheave 70 (that is, the secondary pressure Pout supplied to the secondary side hydraulic actuator 70c) is regulated and controlled by the hydraulic control circuit, whereby the fixed sheave 70a and the movable sheave A secondary thrust Wout (= secondary pressure Pout × pressure receiving area) for changing the V groove width between 70b is applied. In the continuously variable transmission 24, the primary thrust Win (primary pressure Pin) and the secondary thrust Wout (secondary pressure Pout) are controlled to change the V-groove width of each of the sheaves 66 and 70, thereby causing the transmission belt 72 to engage. The diameter (effective diameter) is changed, and the gear ratio γcvt (= primary sheave rotational speed Npri / secondary sheave rotational speed Nsec) is changed, and the transmission belt 72 does not slip, and the transmission belts and the transmission belt The friction force between 72 and 72 is controlled.

  The output shaft 30 is disposed so as to be rotatable relative to the rotation axis 68 coaxially with the rotation axis 68. The second clutch C2 is provided on the drive wheel 14 side (here, the output shaft 30 also agrees) than the continuously variable transmission 24 (ie, provided between the secondary sheave 70 and the output shaft 30), The secondary sheave 70 (rotational shaft 68) and the output shaft 30 are selectively connected and disconnected. The second power transmission path PT2 is formed by engagement of the second clutch C2. In the power transmission device 16, when the second power transmission path PT2 is formed, the power transmission possible state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission 24 Be done. On the other hand, the second power transmission path PT2 is brought into the neutral state when the second clutch C2 is released.

  FIG. 2 is a diagram for explaining switching of the traveling pattern by using an engagement table of the engagement device for each traveling pattern (traveling mode) of the power transmission device 16. In FIG. 2, C1 corresponds to the operating state of the first clutch C1, C2 corresponds to the operating state of the second clutch C2, B1 corresponds to the operating state of the first brake B1, and D1 corresponds to that of the meshing clutch D1. Corresponding to the operating state, "o" indicates engagement (connection) and "x" indicates release (shutoff).

  In FIG. 2, a gear traveling mode is a traveling mode in which power of engine 12 is transmitted to output shaft 30 via gear transmission mechanism 28 (ie, a traveling mode using first power transmission path PT1 via gear transmission mechanism 28). At this time, the first clutch C1 and the meshing clutch D1 are engaged, and the second clutch C2 and the first brake B1 are released. In this gear travel mode, forward travel is possible. When the first brake B1 and the meshed clutch D1 are engaged and the second clutch C2 and the first clutch C1 are released, reverse travel is possible.

  Further, a CVT travel mode is a travel mode in which the power of engine 12 is transmitted to output shaft 30 via continuously variable transmission 24 (ie, a travel mode using second power transmission path PT2 via continuously variable transmission 24). In the belt travel mode, the second clutch C2 is engaged and the first clutch C1 and the first brake B1 are released. In this CVT travel mode, forward travel is possible. Among the CVT travel modes, the meshed clutch D1 is engaged in the CVT travel (medium vehicle speed) mode, while the meshed clutch D1 is released in the CVT travel (high vehicle speed) mode. The meshed clutch D1 functions as a driven input cutoff clutch that blocks an input from the drive wheel 14 side.

  The gear travel mode is selected, for example, in a low vehicle speed region including the time when the vehicle is stopped. In the power transmission device 16, a gear ratio γgear (also referred to as a transmission ratio EL) formed in a first power transmission path PT1 via a gear transmission mechanism 28 is a second power transmission path PT2 via a continuously variable transmission 24. It is set to a value (that is, a transmission ratio on the low side) larger than the maximum transmission ratio (that is, the lowest transmission ratio that is the transmission ratio on the lowest vehicle speed side) which can be formed in. That is, the second power transmission path PT2 is formed with the transmission gear ratio γcvt on the higher vehicle speed side (high side) than the transmission gear ratio EL formed in the first power transmission path PT1. For example, the gear ratio EL corresponds to the first gear ratio γ1 which is the gear ratio γ of the first gear in the power transmission device 16, and the lowest gear ratio γmax of the continuously variable transmission 24 in the power transmission device 16 It corresponds to the second gear ratio γ2 which is the gear ratio γ of the second gear. Therefore, the gear travel mode and the CVT travel mode are switched, for example, in accordance with the shift line for switching between the first shift stage and the second shift stage in the shift map of the stepped transmission. Further, in the CVT travel mode, a shift is performed in which the gear ratio γcvt is changed based on a travel state such as an accelerator opening degree or a vehicle speed.

  FIG. 3 is a cross-sectional view of the primary sheave 66 of the continuously variable transmission 24 of FIG. The primary sheave 66 is formed between a disk-shaped stationary sheave 66a integrally formed on a sheave shaft 78 rotatably supported by the housing 18 of FIG. 1 via a bearing 74 and a bearing 76 and the stationary sheave 66a. In order to form a V-shaped first pulley groove 80, a movable sheave 66b which is relatively non-rotatable and relatively movable in the axial direction relative to the sheave shaft 78, and the movable sheave 66b in the axial direction according to the hydraulic pressure supplied. To move the stationary sheave 66a and the movable sheave 66b axially in the axial direction, thereby changing the groove width of the first pulley groove 80. The sheave shaft 78 is rotatably supported around the first axial center RC1 by bearings 74 and bearings 76 whose outer peripheral ends are fitted to the housing 18. The inner diameter of the movable sheave 66b is formed with a groove whose side surface has an involute curve, and an involute spline fitting (hereinafter referred to as a spline fitting) by a groove formed in the movable sheave 66b and a groove formed in the outer diameter of the sheave shaft 78 As a result, the movable sheave 66b and the sheave shaft 78 can not relatively rotate and can relatively move.

  The stationary sheave 66 a of the primary sheave 66 is a disk-like member that protrudes radially from the outer peripheral surface of the sheave shaft 78. The stationary sheave 66a is formed with a conical tapered surface 82 which is formed in a direction away from the movable sheave 66b in the radial direction.

  The movable sheave 66b of the primary sheave 66 has a boss portion 88 whose inner peripheral portion can be axially moved relative to the sheave shaft 78 and can not be splined relative to the first axial center RC1 and its boss The disk portion 90 projects radially from the end portion on the fixed sheave 66a side in the axial direction of the portion 88, and extends parallel to the first axial center RC1 in the direction away from the fixed sheave 66a in the axial direction from the outer peripheral portion of the disk portion 90 And an outer peripheral cylindrical portion 92. The disc portion 90 is formed with a conical tapered surface 94 which is formed in a direction away from the stationary sheave 66 a in the radial direction. The first pulley groove 80 is formed by the tapered surface 94 formed on the movable sheave 66b and the tapered surface 82 formed on the fixed sheave 66a.

  The hydraulic cylinder 66c includes a bottomed cylindrical cylinder member 96 disposed on the back side of the tapered surface 94 in the axial direction of the movable sheave 66b. The cylinder member 96 has a nut 98 in a state in which the inner peripheral portion thereof is axially sandwiched between the step portion 78a of the sheave shaft 78 and the nut 98 through the disc-like cylinder sheet 100 functioning as a stopper member. By being fastened to an external thread 84 formed at the axial end of the sheave shaft 78, it is fixed so as not to move in the axial direction. The movable sheave 66b contacts the cylinder sheet 100, which is a stopper provided at a fixed position in the direction of the first axial center RC1, to maximize the distance between the movable sheave 66b and the fixed sheave 66a. The gear ratio γcvt is the largest A transmission ratio on the low side, ie, the lowest vehicle speed side is formed. The cylinder member 96 has a bent shape, and a cylindrical portion concentric with the first axis RC1 is formed on the outer peripheral side of the cylinder member 96. The inner peripheral surface of the cylindrical portion and the outer peripheral end of the outer peripheral cylindrical portion 92 of the movable sheave 66b are configured to be slidable via an oil seal. Thus, an oil-tight hydraulic chamber 97 is formed between the cylinder member 96 and the movable sheave 66b. The hydraulic pressure is supplied from a hydraulic control circuit (not shown) to the hydraulic chamber 97 via an oil passage formed on the sheave shaft 78 and an oil passage formed on the movable sheave 66b.

  FIG. 4 is an enlarged view of a part of a movable sheave 66b and a cylinder member 96 which constitute the primary sheave 66 shown in FIG. The movable sheave 66b is in contact with the cylinder sheet 100 which is a stopper, and the distance between the movable sheave 66b and the fixed sheave 66a is the largest, that is, the thrust force of the sheave shaft 78 in the direction of the axial center RC1 The situation is shown in which the gear ratio γcvt is added to the nut 98a via the seat 100 and the cylinder member 96, and the gear ratio at the lowest speed, ie, the lowest vehicle speed side, is formed. The nut 98a of FIG. 4 is a flanged hexagonal nut 98a (hereinafter referred to as a flange nut), and is screwed into the male screw 84 of the sheave shaft 78 of FIG. As described above, the flange nut 98a is fixed by sandwiching the cylinder sheet 100 and the cylinder member 96 between the step portion 78 which is a part of the sheave shaft 78, and the transmission belt 72 is fixed to the movable sheave 66b. The transmitted force is a force which periodically fluctuates between the contact with the transmission belt 72 and the non-contact at each portion of the variable sheave 66b, so that the bearing surface 106 of the flange nut 98a is apt to wear. The flange nut 98 a has a cylindrical portion 102 shown by an arrow in FIG. 4 and forming an outer periphery, a flange-like portion 103 which is a part of the cylindrical portion 102, an internal thread 104 formed on the inner periphery, and a cylinder member 96. And the end face opposite to the cylinder member 96. Further, the flange nut 98a is loosened by plastic deformation of the end of the flange nut 98a, for example. The flange nut 98a makes it easy to take a large contact surface with the bearing surface 106, ie, the cylinder member 96 because of the presence of the flange-like portion 103, and reduces the surface pressure per unit area by making the contact surface large, thereby providing wear resistance. It is possible to improve. On the other hand, as shown by the broken arrow, the radial dimension La of the seating surface 106, that is, the distance (moment arm) La from the contact surface between the cylinder member 96 and the sheave shaft to the flange nut 98a becomes longer. When a thrust force is received in the direction of the first axial center RC1 from the above, a large force is received as a load moment, and the load applied to the internal thread 104 of the flange nut 98a and the external thread 84 of the sheave shaft 78 increases. The durability of the screw 104 and the male screw 84 is reduced.

  FIG. 5 is an enlarged view of a part of the movable sheave 66b and the cylinder member 96 which constitute the conventional primary sheave 66 as in the portion shown in FIG. In FIG. 5, the nut 98 used in FIG. 4 is not the flange nut 98a, but a hexagonal nut 98b is used. When it is desired to reduce the overall size of the hexagonal nut 98b compared to the case where the flange nut 98a is used because there is no flange, it is difficult to enlarge the contact surface with the bearing surface 106, that is, the cylinder member 96. For this reason, it is difficult to reduce the surface pressure per unit area, and it is difficult to improve the wear resistance when receiving a periodically varying thrust force. On the other hand, as shown by the broken arrow, the distance (moment arm) Lb from the end Lb of the seat 106, ie, the contact surface between the cylinder member 96 and the sheave shaft, to the end of the flange nut 98a is compared with the flange nut 98a. Since it becomes possible to reduce the load moment, it is possible to improve the durability of the internal thread 104 of the nut 98b and the external thread 84 of the cylinder shaft 78.

  In FIG. 6, the nut 98 of the present embodiment is shown by enlarging a part of the movable sheave 66b and the cylinder member 96 which constitute the primary sheave 66 in the same manner as the portions shown in FIGS. The nut 98 used in FIG. 6 is preferably a flange portion between the flange-like portion 103 formed on a part of the cylindrical portion 102 of the flange nut 98a and the end surface opposite to the flange-like portion. An outer peripheral groove 108 is formed between 103 and the cylindrical portion 102 having an internal thread 104 formed in the inner peripheral surface. This makes it possible to secure the same area as that of the flange nut 98a, and to reduce the surface pressure per unit area compared to the hexagonal nut 98b. Become. Further, by forming the outer peripheral groove 108, as shown by the broken arrow, the radial dimension from the contact portion between the end Lc of the seat 106, ie, the cylinder member 96 and the sheave shaft, to the groove bottom of the outer peripheral groove 108 By shortening Lc, the load moment is reduced.

  According to the continuously variable transmission 24 of this embodiment, the thrust force of the movable sheave 66b toward the shaft end of the sheave shaft 78 is screwed through the cylinder member 96 by being screwed into the external thread 84 formed on the sheave shaft 78. The nut 98 has a female screw 104 screwed to the male screw 84 and a seat 106 abutting on the cylinder member 96. The seat 106 and cylinder member 96 are opposite to each other in the central axial direction of the nut 98. An outer peripheral groove 108 continuous in the circumferential direction is formed in the cylindrical portion 102 between the end face and the end face. By this, the load moment is determined by the groove bottom diameter of the outer peripheral groove 108. This makes it possible to enlarge the area of the bearing surface 106, that is, the contact surface with the cylinder member 96 where the nut 98 receives the thrust force of the movable sheave 66b without increasing the load moment, and the pressure per unit area decreases. As a result, wear on the contact surface or seating surface 106 can be reduced. Further, by adding the outer peripheral groove 108 to the cylindrical portion 102 of the nut 98, the load moment is determined by the groove bottom diameter of the outer peripheral groove 108, so that the load moment received by the nut 98 can be reduced. Can be made smaller. This also makes it possible to reduce the size and weight of the continuously variable transmission 24.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is also applicable in other aspects.

  In the above embodiment, the outer peripheral groove 108 is provided in the nut 98 holding the movable sheave 66b of the primary sheave 66. However, not only the primary sheave 66 but the movable sheave 70b of the secondary sheave 70 is held by the nut 98. The same effect as the primary sheave 66 can be expected.

  In the above-described embodiment, the cylinder sheet 100 contacts the movable sheave 66b to perform the function as a stopper member. However, the present invention is not limited to the cylinder sheet 100, but may be used to fix the position in the first axial center RC1 direction. For example, hydraulic cylinders 66c and 70c may be used as stoppers.

  In the continuously variable transmission of the embodiment described above, the power is transmitted by the transmission belt 72. However, the invention is not necessarily limited to the transmission belt, and for example, if it is a configuration that can be wound around each pulley such as a chain. It is not particularly limited.

  Furthermore, in the above embodiment, the fixed sheave 66a is integrally formed with the sheave shaft 78. However, it is not necessary to integrally form one in particular, and it is possible to combine by a mechanical method if rigidity is secured. It may be used.

The above description is only one embodiment, and the present invention can be implemented in variously modified and improved modes based on the knowledge of those skilled in the art.

24: Continuously variable transmission (Belt type continuously variable transmission)
66a, 70a: fixed sheave 66b, 70b: movable sheave 72: transmission belt 78: sheave shaft 84: male thread 96: cylinder member 97: hydraulic chamber 98: nut 102: cylindrical portion 104: female thread 106: seating surface 108: Outer peripheral groove

Claims (1)

A fixed sheave integrally formed with the sheave shaft, a movable sheave axially oppositely movable relative to the sheave shaft in a state facing the fixed sheave, and a shaft of the sheave shaft splined relative to the shaft so as not to be relatively rotatable A pair of variable sheaves each having a cylinder member forming an oil pressure chamber for supplying a hydraulic pressure for moving the movable sheave in the axial direction to an end portion side, a transmission belt wound around the pair of variable sheaves And a nut screwed with an external thread formed on the sheave shaft and receiving a thrust force of the movable sheave toward the shaft end of the sheave shaft via the cylinder member. A transmission,
The nut has a female screw engaged with the male screw and a bearing surface abutting on the cylinder member, and the bearing surface and the end surface on the opposite side of the cylinder member in the central axial direction of the nut An outer peripheral groove continuously formed in a circumferential direction is formed in a cylindrical portion between the belts. A belt-type continuously variable transmission for a vehicle.

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