JP6108321B2 - Belt type continuously variable transmission - Google Patents

Description

  The present invention includes a drive pulley composed of a fixed pulley half and a movable pulley half, a driven pulley composed of a fixed pulley half and a movable pulley half, a V surface of the drive pulley, and a V of the driven pulley. A metal belt wound around a surface, wherein the metal belt is configured to support a plurality of metal elements on a metal ring assembly, and the groove width of one of the drive pulley and the driven pulley is increased to increase the other The present invention relates to a belt-type continuously variable transmission that changes a gear ratio by reducing a groove width.

  In such a belt-type continuously variable transmission, the radially inner portion and the outer portion of the V surface of the stationary pulley half of the pulley are configured by straight lines and curves, respectively, and the radially outer portion of the pulley contact surface of the metal element and The inner part is composed of straight and curved lines, and the pulley and metal element are in line contact with each other at the part where the winding diameter of the metal belt on the pulley is small, and the pulley and metal at the part where the winding diameter on the pulley of the metal belt is large Patent Document 1 listed below compensates for misalignment in which the metal belt shifts in the axial direction of the pulley in accordance with the change in the gear ratio of the belt-type continuously variable transmission by making point contact between the curves. .

Japanese Patent No. 5689973

  By the way, although the above-mentioned conventional one can compensate for misalignment of the metal belt, the winding diameter of the metal belt is large as described in detail in the section of the embodiment for carrying out the invention of the present specification. In the region, there is a problem that a large gap is generated between the V surface of the pulley and the radially outer end of the pulley contact surface of the metal element. When such a gap occurs, the left and right outer ends of the metal ring assembly supported on the saddle surface of the metal element project over the gap, and the contact area between the saddle surface and the metal ring assembly decreases accordingly. By doing so, there is a concern that the contact surface pressure is increased and the durability of the metal element or the metal ring assembly is adversely affected.

  The present invention has been made in view of the above circumstances. In a belt-type continuously variable transmission in which a pulley and a metal element are brought into line contact and point contact according to a winding diameter of a metal belt, when the winding diameter of the metal belt is large. The object is to minimize the gap generated between the V surface of the pulley and the radially outer end of the pulley contact surface of the metal element.

  To achieve the above object, according to the first aspect of the present invention, a drive pulley comprising a stationary pulley half and a movable pulley half, and a stationary pulley half and a movable pulley half are provided. A driven pulley; a V-plane of the drive pulley; and a metal belt wound around the V-plane of the driven pulley. The metal belt is configured by supporting a plurality of metal elements on a metal ring assembly, and the drive A belt-type continuously variable transmission that changes a gear ratio by increasing one groove width of the pulley and the driven pulley and decreasing the other groove width of the drive pulley and the driven pulley. The bus comprises a pulley-side straight portion radially inward from the pulley-side inflection point, and a pulley-side curved portion radially outward from the pulley-side inflection point, The pulley contact surface of the metal element is located on the radially outer side with respect to the element side inflection point and can be brought into contact with the pulley side straight part, and the element side linear point with respect to the element side inflection point. An element-side curved portion that is located on the inner side and is capable of contacting the pulley-side curved portion, wherein the element-side curved portion is positioned radially inward of the element-side linear portion, and A second arcuate portion positioned radially inward of the first arcuate portion, wherein the first arcuate portion and the second arcuate portion simultaneously contact the pulley-side curve portion at at least one speed ratio. A belt type continuously variable transmission is proposed.

  According to the invention described in claim 2, in addition to the structure of claim 1, the radius of curvature of the second arc portion is larger than the radius of curvature of the first arc portion, and the pulley-side straight portion and the pulley A belt type continuously variable transmission is proposed in which the second arcuate portion does not contact the pulley-side linear portion when the element-side linear portion abuts.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the element-side curved portion smoothly connects the first arc portion and the second arc portion. A belt type continuously variable transmission including a connecting portion is proposed.

  According to the invention described in claim 4, in addition to the structure of any one of claims 1 to 3, a saddle surface of the metal element and the metal ring assembly supported by the saddle surface The crowning of the saddle surface is biased outward in the lateral direction by a predetermined distance with respect to the crowning of the metal ring assembly, and the predetermined distance is A belt type continuously variable transmission is proposed, which is set to be larger than a gap generated between the V surface and the radially outer end of the pulley contact surface.

  According to the configuration of the first aspect of the present invention, the V-plane bus of the drive pulley and the driven pulley includes a pulley-side straight portion radially inward of the pulley-side inflection point and a pulley radially outward of the pulley-side inflection point. The pulley contact surface of the metal element includes an element side straight line portion radially outward from the element side inflection point and an element side curve portion radially inward from the element side inflection point. Therefore, when the wrapping radius of the metal belt is small, the pulley-side straight portion and the element-side straight portion abut each other, and when the metal belt wrapping radius is large, the pulley-side curved portion and the element-side curved portion abut each other. The misalignment of the metal belt can be reduced.

  In the conventional metal element, when the winding radius of the metal belt is increased and the pulley-side curved portion and the element-side curved portion abut each other, the element-side curved portion and the pulley-side curved portion are increased as the winding radius increases. Since this contact point is displaced radially inward, there is a problem that a large gap is generated between the V surface of the pulley and the radially outer end portion of the pulley contact surface of the metal element.

  However, the element-side curved portion of the metal element of the present invention includes a first arc portion positioned radially inward of the element-side straight portion and a second arc portion positioned radially inward of the first arc portion. In addition, since the first arc portion and the second arc portion are simultaneously in contact with the pulley-side curve portion at at least one speed ratio, the contact point between the element-side curve portion and the pulley-side curve portion becomes a diameter as the winding radius increases. It is possible to prevent the gap between the V surface of the pulley and the radially outer end portion of the pulley contact surface of the metal element from being reduced, and the pulley side curve portion and the element side curve. It is possible to prevent a load acting between the portions from being distributed to the two contact points of the first arc portion and the second arc portion, thereby generating an excessive contact surface pressure.

  According to the configuration of claim 2, the radius of curvature of the second arc portion is larger than the radius of curvature of the first arc portion, and when the pulley side linear portion and the element side linear portion abut, the second arc portion is a pulley. Since it does not contact the side linear portion, it is possible to prevent the second arc portion from being in contact with the pulley-side linear portion and causing partial wear in the gear ratio region where the pulley-side linear portion and the element-side linear portion abut. it can.

  According to the configuration of claim 3, the element-side curved portion includes the connecting portion that smoothly connects the first arc portion and the second arc portion, so that the first arc portion and the second arc portion are sharp. It is possible to prevent stress concentration from occurring at the corners.

  According to the fourth aspect of the present invention, the saddle surface of the metal element and the metal ring assembly supported by the saddle surface are each crowned in the left-right direction. It is biased outward in the left-right direction by a predetermined distance with respect to the apex of the crowning of the assembly, and the predetermined distance is set larger than the gap generated between the V surface and the radially outer end of the pulley contact surface. Therefore, the metal ring assembly is urged outward in the left-right direction with respect to the saddle surface by the centering action in which the two vertices of the crowning try to coincide with each other, and the outer edge in the left-right direction of the metal ring assembly abuts the V-plane. Thus, the random movement of the metal ring assembly in the left-right direction is suppressed, and the behavior of the metal ring assembly is stabilized.

The skeleton figure of the power transmission system of the vehicle carrying a belt type continuously variable transmission. (First embodiment) The fragmentary perspective view of a metal belt. (First embodiment) Explanatory drawing of the reason why misalignment occurs in the conventional example. (First embodiment) The figure which shows the shape of the bus-line of the V surface of a pulley, and the schematic shape of the pulley contact surface of a metal element. (First embodiment) Explanatory drawing of the reason for which misalignment is compensated in embodiment. (First embodiment) The figure which shows the state which a metal element contact | abuts to the V surface of a pulley in the position where a winding diameter is small. (First embodiment) The figure which shows the state which a metal element contact | abuts to the V surface of a pulley in the position where a winding diameter is large. (First embodiment) The detail drawing of the contact part of the metal element of embodiment and the V surface of a pulley (state where a winding diameter is large). (First embodiment) The detail drawing of the contact part of the metal element of embodiment and the V surface of a pulley (state where a winding diameter is small). (First embodiment) The detail drawing of the contact part of the conventional metal element and the V surface of a pulley (the 1). (First embodiment) The detail drawing of the contact part of the conventional metal element and the V surface of a pulley (the 2). (First embodiment) The figure corresponding to FIG. (Second Embodiment)

First embodiment

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a belt type continuously variable transmission T for a vehicle includes a drive shaft 11 and a driven shaft 12 arranged in parallel, and a crankshaft 13 of an engine E is connected to a drive shaft 11 via a damper 14. Connected to.

  The drive pulley 15 supported by the drive shaft 11 includes a fixed pulley half 15a that is rotatable relative to the drive shaft 11, and a movable pulley half that is axially slidable relative to the fixed pulley half 15a. And a body 15b. The groove width between the movable pulley half body 15 b and the fixed pulley half body 15 a is variable by the hydraulic pressure acting on the hydraulic oil chamber 16. The driven pulley 17 supported by the driven shaft 12 includes a fixed pulley half 17a fixed to the driven shaft 12 and a movable pulley half 17b that is slidable in the axial direction with respect to the fixed pulley half 17a. With. The groove width between the movable pulley half 17 b and the fixed pulley half 17 a is variable by the hydraulic pressure acting on the hydraulic oil chamber 18. And between the drive pulley 15 and the driven pulley 17, the metal belt 19 which attached many metal elements to the two metal ring aggregates is wound.

  A forward clutch 20 that engages the shaft end of the drive shaft 11 when establishing the forward shift speed and transmits the rotation of the drive shaft 11 to the drive pulley 15 in the same direction, and engages when the reverse speed shift stage is established. A forward / reverse switching mechanism 22 comprising a single pinion planetary gear mechanism is provided, which includes a reverse brake 21 that transmits the rotation of the drive shaft 11 to the drive pulley 15 in the reverse direction. The sun gear 23 of the forward / reverse switching mechanism 22 is fixed to the drive shaft 11, the carrier 24 can be bound to the casing 25 by the reverse brake 21, and the ring gear 26 can be coupled to the drive pulley 15 by the forward clutch 20. A plurality of pinions 27 supported by the carrier 24 mesh with the sun gear 23 and the ring gear 26 simultaneously.

  A starting clutch 28 provided at the shaft end of the driven shaft 12 couples the first reduction gear 29 supported on the driven shaft 12 so as to be relatively rotatable. A second reduction gear 31 that meshes with the first reduction gear 29 is fixed to a reduction shaft 30 that is arranged in parallel with the driven shaft 12. A final drive gear 34 fixed to the reduction shaft 30 meshes with a final driven gear 33 fixed to the gear box 32 of the differential gear D. A pair of pinions 36 and 36 supported on the gear box 32 via pinion shafts 35 and 35 are engaged with side gears 39 and 39 provided at the front ends of the left axle 37 and the right axle 38 which are supported relatively rotatably on the gear box 32. To do. Drive wheels W, W are connected to the ends of the left and right axles 37, 38, respectively.

  Therefore, when the forward range is selected by the select lever, the forward clutch 20 is first engaged by a command from the hydraulic control unit U2 operated by the electronic control unit U1, and as a result, the drive shaft 11 is integrally coupled to the drive pulley 15. Is done. Subsequently, the starting clutch 28 is engaged, and the torque of the engine E is driven by the drive shaft 11 → the forward / reverse switching mechanism 22 → the drive pulley 15 → the metal belt 19 → the driven pulley 17 → the driven shaft 12 → the starting clutch 28 → the first reduction gear 29. The second reduction gear 31 → the reduction shaft 30 → the final drive gear 34 → the final driven gear 33 → the differential gear D → the axles 37 and 38 are transmitted to the drive wheels W and W, and the vehicle starts moving forward. When the reverse range is selected with the select lever, the reverse brake 21 is engaged by the command from the hydraulic control unit U2, and the drive pulley 15 is driven in the direction opposite to the rotational direction of the drive shaft 11, so that the start clutch 28 is engaged. As a result, the vehicle starts moving backward.

  When the vehicle starts in this way, the hydraulic pressure supplied to the hydraulic oil chamber 16 of the drive pulley 15 in response to a command from the hydraulic control unit U2 increases, and the movable pulley half 15b of the drive pulley 15 becomes fixed side pulley half. As the effective radius increases toward 15a, the hydraulic pressure supplied to the hydraulic oil chamber 18 of the driven pulley 17 decreases, and the movable pulley half 17b of the driven pulley 17 moves away from the fixed pulley half 17a. As the effective radius decreases, the gear ratio of the belt type continuously variable transmission T continuously changes from the LOW side to the OD side.

  As shown in FIG. 2, the metal belt 19 includes a pair of left and right metal ring assemblies 41, 41 that support a number of metal elements 42, and each metal ring assembly 41 includes a plurality of metal rings 43. It is constructed by stacking. A metal element 42 formed by punching from a metal plate material has an element main body 44, a neck portion 46 positioned between a pair of left and right ring slots 45, 45 with which the metal ring assemblies 41, 41 are engaged, and a neck portion 46. And a substantially triangular ear portion 47 connected to the outside of the element body 44 in the radial direction. A pair of pulley contact surfaces 49, 49 that can contact the V surfaces 48, 48 (see FIG. 1) of the drive pulley 15 and the driven pulley 17 are formed at both left and right ends of the element body 44.

  In this specification, the front-rear direction is defined as the forward direction of the metal belt 19, the radial direction is defined as the radial direction of the drive pulley 15 or the driven pulley 17, and the left-right direction is defined as the drive pulley 15 or the driven pulley 17. Defined as the axial direction.

  Next, the reason why misalignment C occurs in the metal belt 19 will be described with reference to FIG.

  The drive pulley 15 and the driven pulley 17 are arranged in a positional relationship in which a line connecting the fixed pulley halves 15a and 17a and a line connecting the movable pulley halves 15b and 17b intersect. For example, on the drive pulley 15 side, the fixed pulley half 15a is disposed on the left side and the movable pulley half 15b is disposed on the right side. Conversely, on the driven pulley 17 side, the fixed pulley half 17a is disposed on the right side and the movable pulley half 17b. Is placed on the left. By adopting such an arrangement, misalignment C of the metal belt 19 that occurs in association with a change in the gear ratio can be minimized.

  FIG. 3B shows a state where the gear ratio i is MID (1.0). In this state, the groove center line L1 of the drive pulley 15 and the groove center line L2 of the driven pulley 17 are aligned, and the metal belt The whole 19 is arranged in the same plane, and the misalignment C becomes zero.

  FIG. 3A shows a state in which the gear ratio i is LOW. In this state, the movable pulley half 15b of the drive pulley 15 moves to the right so as to be separated from the fixed pulley half 15a, and the groove center The line L1 moves to the right, and the movable pulley half 17b of the driven pulley 17 moves to the right so as to approach the fixed pulley half 17a, and the groove center line L2 moves to the right. Thus, when the gear ratio i is LOW, the movable pulley half 15b of the drive pulley 15 and the movable pulley half 17b of the driven pulley 17 both move to the right side, and the groove center line of both pulleys 15 and 17 Since both L1 and L2 move to the right, the occurrence of misalignment C is minimized, but the amount of movement of the drive pulley 15 to the right of the groove center line L1 is to the right of the groove center line L2 of the driven pulley 17. Therefore, there is a misalignment C in which the driven pulley 17 side is biased to the left with respect to the drive pulley 15 side.

  FIG. 3C shows a state in which the transmission gear ratio i is OD. In this state, the movable pulley half 15b of the drive pulley 15 moves to the left side so as to approach the fixed pulley half 15a and moves to the center of the groove. The line L1 moves to the left side, and the movable pulley half 17b of the driven pulley 17 moves to the left so as to be separated from the fixed pulley half 17a, and the groove center line L2 moves to the left. Thus, when the transmission ratio i is OD, the movable pulley half 15b of the drive pulley 15 and the movable pulley half 17b of the driven pulley 17 both move to the left, and the groove center line of both pulleys 15, 17 Since both L1 and L2 move to the left, the occurrence of misalignment C is minimized, but the amount of movement of the drive pulley 15 to the left of the groove center line L1 is to the left of the groove center line L2 of the driven pulley 17. Therefore, there is a misalignment C in which the driven pulley 17 side is biased to the left with respect to the drive pulley 15 side.

  FIG. 4 shows the shape of the V surface 48 of the stationary pulley half 15a of the drive pulley 15 of the present embodiment and the schematic shape of the pulley contact surface 49 of the metal element 42 contacting therewith. . The generatrix of the V surface 48 which is basically a conical surface has a pulley side inflection point 48a located in the middle in the radial direction and a pulley side straight line portion formed by a straight line located radially inward of the pulley side inflection point 48a. 48b and a pulley-side curve portion 48c made of a curve located radially outward from the pulley-side inflection point 48a. The pulley-side straight portion 48 b extending radially inward from the pulley-side inflection point 48 a is a straight line that is inclined at an angle θ with respect to a plane orthogonal to the drive shaft 11. The pulley-side curve portion 48c extending radially outward from the pulley-side inflection point 48a is a smooth curve in which the angle formed by the tangent to the plane perpendicular to the drive shaft 11 increases from θ to θ + Δθ.

  On the other hand, the pulley contact surface 49 of the metal element 42 that can contact the V surface 48 is basically a belt-like surface extending in the radial direction, and an element side inflection point 49a located in the middle in the radial direction, An element-side straight line portion 49b made of a straight line located radially outward from the inflection point 49a and an element-side curved portion 49c made of a curve located radially inward of the element-side inflection point 49a. The element side straight line portion 49 b extending radially outward from the element side inflection point 49 a is a straight line that is inclined at an angle θ with respect to a plane orthogonal to the drive shaft 11. The element-side curve portion 49c extending radially inward from the element-side inflection point 49a is basically a curve in which the angle formed by the tangent to the plane perpendicular to the drive shaft 11 increases from θ to θ + Δθ. However, it actually has a more complicated shape shown in FIG. 8, and the specific shape will be described in detail later.

  Therefore, when the metal element 42 moves relative to the drive pulley 15 inward in the radial direction, the pulley-side straight portion 48b and the element-side straight portion 49b can be in line contact with each other. When 42 moves relatively inward in the radial direction, the pulley-side curved portion 48c and the element-side curved portion 49c can make point contact with each other.

  The shape of the V surface 48 of the stationary pulley half 17a of the driven pulley 17 and the shape of the pulley abutting surface 49 of the metal element 42 that abuts on the V side 48 of the fixed pulley half 15a of the drive pulley 15 are described above. The shape of the surface 48 is the same as the shape of the pulley contact surface 49 of the metal element 42 that contacts the surface 48.

  Note that the positions of the movable pulley halves 15b and 17b of the drive pulley 15 and the driven pulley 17 in the axial direction are not fixed, and may be moved closer to and away from the counterpart fixed pulley halves 15a and 17a. Therefore, the shape of the bus bar of the V surface 48 of the movable pulley halves 15b and 17b does not affect the misalignment C compensation. However, in the present embodiment, the shape of the bus bar of the V surface 48 of the movable pulley half 15b of the drive pulley 15 is symmetrical to the shape of the bus bar of the V surface 48 of the fixed pulley half 15a. The shape of the bus bar of the V surface 48 of the movable pulley half body 17b of 17 is made symmetrical with the shape of the bus bar of the V surface 48 of the stationary pulley half body 17a.

  In FIG. 4, when the pulley contact surface 49 of the metal element 42 moves relative to the V surface 48 of the stationary pulley half 15a of the drive pulley 15 radially outward, the first half gear ratio i changes from LOW to MID. In the process of moving toward (1.0), the pulley-side linear portion 48b and the element-side linear portion 49b are in line contact with each other, so that the metal element 42 moves slowly to the left side in the drawing with respect to the V plane 48. However, in the process in which the gear ratio i in the latter half shifts from MID (1.0) toward OD, the pulley-side curved portion 48c and the element-side curved portion 49c are in point contact, so that the metal element 42 has the V plane 48. Suddenly moves to the left in the figure.

  In the conventional example shown in FIG. 3, for example, when the gear ratio i shifts from the MID in FIG. 3 (B) to the OD in FIG. 3 (C), the drive pulley 15 is wound when the gear ratio i is MID. The metal element 42 of the metal belt 19 and the metal element 42 of the metal belt 19 wound around the driven pulley 17 are aligned in the axial direction. Therefore, the misalignment C is zero, but the drive is performed when the gear ratio i is OD. Misalignment C occurs because the metal element 42 of the metal belt 19 wound around the driven pulley 17 is biased to the left in the axial direction with respect to the metal element 42 of the metal belt 19 wound around the pulley 15.

  However, as is apparent from FIGS. 5B and 5C, according to the present embodiment, the driven pulley having a small winding diameter of the metal belt 19 in the process of shifting the transmission ratio i from MID to OD. On the 17th side, the pulley-side straight portion 48b of the V surface 48 and the element-side straight portion 49b of the pulley contact surface 49 are in contact with each other, so the amount of movement of the metal element 42 to the left in the axial direction is small. On the drive pulley 15 side where the winding diameter is large, the pulley-side curved portion 48c of the V surface 48 and the element-side curved portion 49c of the pulley contact surface 49 abut, so the amount of movement of the metal element 42 to the left in the axial direction increases. The misalignment C that should have occurred due to the difference in the amount of movement is canceled out, and the misalignment C is set to zero or low to a value close to zero. It can be.

  In the conventional example shown in FIG. 3, for example, when the gear ratio i shifts from MID in FIG. 3B to LOW in FIG. 3A, the drive pulley 15 is wound when the gear ratio i is MID. The metal element 42 of the metal belt 19 and the metal element 42 of the metal belt 19 wound around the driven pulley 17 are aligned in the axial direction. Therefore, the misalignment C is zero, but the drive is performed when the gear ratio i is LOW. Misalignment C occurs because the metal element 42 of the metal belt 19 wound around the driven pulley 17 is biased to the left in the axial direction with respect to the metal element 42 of the metal belt 19 wound around the pulley 15.

  However, as is apparent from FIGS. 5B and 5A, according to the present embodiment, the drive pulley having a small winding diameter of the metal belt 19 in the process in which the gear ratio i shifts from MID to LOW. On the 15th side, the pulley-side straight portion 48b of the V surface 48 and the element-side straight portion 49b of the pulley contact surface 49 are in contact with each other, so the amount of movement of the metal element 42 to the right in the axial direction is small. On the driven pulley 17 side where the winding diameter is large, the pulley-side curved portion 48c of the V surface 48 and the element-side curved portion 49c of the pulley contact surface 49 abut, so the amount of movement of the metal element 42 to the right in the axial direction increases. The misalignment C, which should have occurred due to the difference in the amount of movement, is canceled out, and the misalignment C is set to zero or close to zero. It can be reduced.

  In this way, the pulley-side straight portion 48b and the pulley-side curved portion 48c are formed on the V surface 48 of the drive pulley 15 and the driven pulley 17, and the element-side straight portion 49b and the element side are formed on the pulley contact surface 49 of the metal element 42. By forming the curved portion 49c, the misalignment C can be compensated for the metal belt 19 that is generated as the speed ratio i is changed. Therefore, the metal belt 19 does not receive an axial load and the drive pulley 15 and It can be aligned with the groove center of the driven pulley 17, and the metal elements 42 of the metal belt 19 can be smoothly engaged with the drive pulley 15 and the V surface 48 of the driven pulley 17 and are durable due to abnormal wear or the like. Deterioration can be prevented.

  As described above, by making the shapes of the pulley-side curved portion 48c of the V surface 48 and the element-side curved portion 49c of the pulley contact surface 49 into curved shapes that are curved by an amount corresponding to the misalignment C, the misalignment C Can be compensated for. On the other hand, as shown in FIG. 10, the shape of the conventional metal element 42 is such that when the winding diameter of the metal belt 19 is increased, the pulley side curved portion 48 c of the V surface 48 and the element side curved portion 49 c of the pulley contact surface 49. The contact point P of the metal element gradually moves radially inward on the element-side curved portion 49c, so that the distance d between the contact point P and the saddle surface 50 of the metal element 42 increases. As a result, as the winding diameter of the metal belt 19 increases, the clearance α between the radially outer end portion of the pulley contact surface 49 (the lateral end portion of the saddle surface 50) and the V surface 48 increases. It will be. The radially outer end of the pulley contact surface 49 is a position that is assumed to be sharp without being chamfered.

  As shown in FIGS. 6 and 7, the saddle surface 50 of the metal element 42 and the metal rings 43... Of the metal ring assembly 41 are respectively subjected to crowning in the left-right direction. In the initial state (design value), the metal ring 43 is offset outward in the left-right direction by a distance β in the initial state (design value).

  To explain this further, FIG. 6 shows a state in which the winding diameter of the metal belt 19 is small and the pulley-side straight portion 48b and the element-side straight portion 49b are in contact with each other. The two vertices C1 and C2 are shifted by a distance β which is a set value. Therefore, the metal ring assembly 41 is urged outward in the left-right direction with respect to the saddle surface 50 by the centering action in which the two vertices C1 and C2 of the crowning try to coincide with each other. By contacting 48, random movement in the left-right direction of the metal ring assembly 41 is suppressed, and the behavior of the metal ring assembly 41 is stabilized.

  On the other hand, FIG. 7 shows a state in which the winding diameter of the metal belt 19 is maximum and the pulley-side curved portion 48c and the element-side curved portion 49c are in contact with each other. At this time, the gap α is the maximum αmax. The metal ring assembly 41 moves by a distance corresponding to the gap αmax to the outside in the left-right direction with respect to the saddle surface 50 by the centering action in which the two vertices C1 and C2 of the crowning try to coincide with each other. The distance β ′ between the two crowning vertices C1 and C2 is maintained at a positive value larger than zero. Therefore, even when the winding diameter of the metal belt 19 becomes the maximum and the gap α becomes the maximum αmax, the relationship β> αmax is always established. Therefore, the outer edge in the left-right direction of the metal ring assembly 41 is surely in contact with the V surface 48, and random movement of the metal ring assembly 41 in the left-right direction is suppressed, so that the behavior of the metal ring assembly 41 is stabilized.

  The gap α increases from 0 as the winding diameter becomes larger than the pulley-side inflection point 48a, and becomes αmax at the maximum winding diameter. Further, β> αmax, which is the relationship between the design value β and the maximum gap αmax, is applied to all the metal rings 43 on the outermost periphery of the metal ring assembly 41.

  However, in FIG. 10, when the gap α between the radially outer end of the pulley contact surface 49 and the V surface 48 increases, the metal ring assembly 41 urged outward in the left-right direction by the crowning becomes the saddle surface 50. And the contact area between the saddle surface 50 and the metal ring assembly 41 is reduced and the contact surface pressure is increased, thereby improving the durability of the metal element 42 and the metal ring assembly 41. There are concerns about adverse effects. Therefore, when the winding diameter of the metal belt 19 increases, it is desirable to keep the gap α between the radially outer end of the pulley contact surface 49 and the V surface 48 as small as possible.

  Therefore, as shown in FIG. 11, the pulley contact surface 49 that contacts the pulley-side curved portion 48 c of the V surface 48 is shifted radially outward from the contact point P of the pulley contact surface 49, and the contact point P and the saddle surface 50 of the metal element 42 If the distance d is reduced, the gap α can be kept small. However, even if the contact point P is shifted outward in the radial direction, the element-side curve portion 49c has a shape of the conventional element-side curve portion 49c, and the element-side curve portion on the radially inner side of the contact point P when the winding diameter of the metal belt 19 increases. Since 49c interferes with the pulley-side curved portion 48c (see the hatched portion in FIG. 11), it is difficult to shift the contact point P radially outward.

  FIG. 8 shows the detailed shape of the element-side curved portion 49c of the metal element 42 of the present embodiment, and this element-side curved portion 49c has a radius that smoothly connects to the radially inner side of the element-side linear portion 49b. A first arc portion A1 of R1 and a second arc portion A2 of radius R2 connected to the inside of the first arc portion A1 in the radial direction via a corner portion. The curvature radius R2 of the second arc portion A2 is set larger than the curvature radius R1 of the first arc portion A1. As a result, a space γ recessed inward in the left-right direction is formed between the first arc portion A1 and the second arc portion A2, and the first arc portion A1 comes into contact with the V surface 48 at the main contact point P1, and the second The arc portion A2 comes into contact with the V surface 48 at the sub contact point P2.

  As shown in FIG. 9, when the wrapping diameter of the metal belt 19 is smaller than the state in which the speed ratio i is MID (1.0), the element-side straight portion 49b and the pulley-side straight portion 48b are in a line contact state. . In the present embodiment, when the winding diameter of the metal belt 19 increases from here and the speed ratio i reaches the vicinity of the state of MID (1.0), the element side curve portion 49c and the pulley side curve portion 48c are The two abutment points P1 and P2 contact each other. If the winding diameter of the metal belt 19 further increases from here, the secondary contact point P2 is geometrically maintained in the contact state, and the main contact point P1 is lifted from the V plane 48. In other words, when trying to maintain the main contact point P1 in the contact state, the vicinity of the sub contact point P2 interferes with the pulley-side curve portion 48c (see the hatched portion in FIG. 8), and the main contact point P1 is in the contact state. Cannot be maintained.

  However, triangular concave portions 51 and 51 are formed on both ends of the lower edge of the main body 44 of the metal element 42 in the left-right direction, and the element-side curved portion 49c can be elastically deformed relatively easily inward in the left-right direction. For this reason, the secondary contact point P2 is displaced inward in the left-right direction by this elastic deformation, so that the contact state at the two points of the main contact point P1 and the secondary contact point P2 can be maintained.

  By forming the pulley contact surface 49 of the metal element 42 as described above, when the metal belt 19 is radially inward of the gear ratio i from the position of MID (1.0), the pulley-side linear portion 48b and the element The side straight portion 49b can be brought into contact with the gap α to be zero (see FIG. 9). Further, when the metal belt 19 is located radially outside the position where the gear ratio i is MID (1.0), as shown in FIG. 8, the pulley-side curve portion 48c and the element-side curve portion 49c are connected to the main contact point P1 and Abutting at two points of the secondary contact point P2, a space γ recessed inward in the left-right direction exists on the radially inner side of the first arc part A1 having a small curvature radius R1, and the first arc part A1 is locally left and right. Since it protrudes outward in the direction, the position of the main contact point P1 of the first arc portion A1 is maintained substantially constant even if the position of the metal belt 19 moves outward in the radial direction. As a result, the gap α between the radially outer end of the pulley contact surface 49 and the V surface 48 is prevented from increasing as the position of the metal belt 19 moves radially outward. In the speed ratio region, the size of the gap α is minimized. Therefore, the amount by which the left and right outer ends of the metal ring assembly 41 project over the gap α is reduced, and the increase in contact surface pressure between the metal ring assembly 41 and the saddle surface 50 is suppressed, thereby improving durability. it can.

  In addition, if the pulley-side curved portion 48c and the element-side curved portion 49c are in contact only at the main contact point P1, the contact surface pressure at the main contact point P1 may be excessively increased and the durability may be adversely affected. According to the present embodiment, the pulley-side curved portion 48c and the element-side curved portion 49c are in contact at two points of the main contact point P1 and the sub contact point P2, thereby reducing the contact surface pressure and ensuring durability. be able to.

  Note that when the metal belt 19 is radially inward from the position where the gear ratio i is MID (1.0) and the pulley-side linear portion 48b and the element-side linear portion 49b are in line contact, the element-side curved portion 49c The two arc portions A2 do not contact the pulley-side straight portion 48b (see FIG. 9). Accordingly, it is possible to prevent the second arcuate portion A2 from being in contact with the pulley-side linear portion 48b and causing partial wear in the gear ratio region where the pulley-side linear portion 48b and the element-side linear portion 29b are in contact.

Second embodiment

  In the first embodiment, since the first arc portion A1 and the second arc portion A2 constituting the element side curved portion 49c intersect at a sharp corner (see FIG. 8), stress concentration occurs in that portion. there is a possibility. In the second embodiment shown in FIG. 12, the first arc part A1 and the second arc part A2 are connected by a connecting part A3 made of a smooth curve and are prevented from intersecting at sharp corners. Thus, it is possible to avoid the occurrence of stress concentration at the sharp corner.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, when the gear ratio i reaches the vicinity of the MID (1.0) state, the element-side curve portion 49c and the pulley-side curve portion 48c are at two points, the main contact point P1 and the sub contact point P2. When the winding diameter of the metal belt 19 increases from here on, the two points of the main contact point P1 and the sub contact point P2 are maintained in contact with each other due to elastic deformation of the metal element 42, but the speed ratio i is When the vicinity of the MID (1.0) state is reached, the element-side curved portion 49c and the pulley-side curved portion 48c come into contact with each other only at the main contact point P1, and the winding diameter of the metal belt 19 increases from here. Only the main contact point P1 is contacted and the sub contact point P2 is not contacted. When the winding diameter of the metal belt 19 is further increased, the two points of the main contact point P1 and the sub contact point P2 are contacted simultaneously. Also good. That is, two points of the main contact point P1 and the sub contact point P2 may contact at the same time in at least one speed ratio in the entire speed ratio region.

15 drive pulley 15a fixed pulley half 15b movable pulley half 17 driven pulley 17a fixed pulley half 17b movable pulley half 19 metal belt 41 metal ring assembly 42 metal element 48 V surface 48a pulley side inflection point 48b Pulley side linear portion 48c Pulley side curved portion 49 Pulley contact surface 49a Element side inflection point 49b Element side linear portion 49c Element side curved portion 50 Saddle surface A1 First arc portion A2 Second arc portion A3 Connection portion C1 Saddle surface Crowning vertex C2 Crowning vertex R1 of metal ring assembly Curvature radius R2 of first arc portion Curvature radius α of second arc portion Clearance generated between V surface and radially outer end of pulley contact surface Predetermined distance between two vertices of β crowning

Claims (4)

A drive pulley (15) composed of a fixed pulley half (15a) and a movable pulley half (15b), and a driven pulley (17) composed of a fixed pulley half (17a) and a movable pulley half (17b) And a metal belt (19) wound around the V surface (48) of the drive pulley (15) and the V surface (48) of the driven pulley (17), the metal belt (19) being a metal ring A plurality of metal elements (42) are supported by the assembly (41), and one groove width of the drive pulley (15) and the driven pulley (17) is increased and the other groove width is decreased. It is a belt type continuously variable transmission that changes the gear ratio with
The generatrix of the V surface (48) of the drive pulley (15) and the driven pulley (17) includes a pulley-side straight portion (48b) radially inward of the pulley-side inflection point (48a) and the pulley side. A pulley-side curve portion (48c) radially outward from the inflection point (48a),
The pulley contact surface (49) of the metal element (42) is located radially outside the element side inflection point (49a) and can contact the pulley side straight portion (48b). (49b) and an element-side curved portion (49c) that is located radially inward of the element-side inflection point (49a) and can contact the pulley-side curved portion (48c),
The element-side curved portion (49c) is located radially inward of the first arc portion (A1) and the first arc portion (A1) located radially inward of the element-side straight portion (49b). The first arc portion (A1) and the second arc portion (A2) simultaneously contact the pulley-side curve portion (48c) at at least one speed ratio. A belt-type continuously variable transmission.   The radius of curvature (R2) of the second arc portion (A2) is larger than the radius of curvature (R1) of the first arc portion (A1), and the pulley side straight portion (48b) and the element side straight portion (49b). 2. The belt-type continuously variable transmission according to claim 1, wherein the second arcuate portion (A2) does not abut against the pulley-side linear portion (48b) when the abuts.   The element-side curved portion (49c) includes a connecting portion (A3) that smoothly connects the first arc portion (A1) and the second arc portion (A2). The belt-type continuously variable transmission according to claim 2.   The saddle surface (50) of the metal element (42) and the metal ring assembly (41) supported by the saddle surface (50) are respectively crowned in the left-right direction, and the saddle surface (50) The crowning vertex (C1) of the metal ring assembly (41) is offset laterally outward by a predetermined distance (β) with respect to the crowning vertex (C2) of the metal ring assembly (41), and the predetermined distance (β) is The gap (α) generated between the V surface (48) and the radially outer end of the pulley contact surface (49) is set to be larger than the clearance (α). The belt type continuously variable transmission according to any one of the above.

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