JP5088241B2 - Continuously variable transmission - Google Patents

Description

  The present invention relates to a continuously variable transmission (CVT), and more particularly, to a continuously variable transmission in which a tooth attached to a pulley and a driving force transmitting means for transmitting a driving force mesh with each other.

Conventionally, for example, a “continuously variable transmission mechanism” (see Patent Document 1) is known as a continuously variable transmission that transmits a rotational driving force using a V-belt.
The conventional “continuously variable transmission mechanism” uses a V-belt between a pulley attached to a drive rotary shaft and a pulley attached to a driven rotary shaft in order to reliably transmit the rotational force using the V-belt. In a V-belt continuously variable transmission mechanism that transmits rotational driving force and at least one of the two pulleys is a variable pitch pulley, the V belt is a toothed V belt, and at least one of the variable pitch pulleys is V It has a gear which meshes with the teeth of the V belt at the groove bottom.
JP-A-63-120950

However, in the conventional “continuously variable transmission mechanism”, the gear that meshes with the teeth of the V belt, which the variable pitch pulley has on the V groove bottom, is fixed to the shaft of the V groove bottom. When the teeth attached to the shaft and the teeth of the V-belt are not sufficiently meshed with each other, the pitches of both teeth do not match, so that the teeth attached to the shaft inevitably attack the V-belt.
In other words, the coordinated movement between the teeth installed on the shaft of the bottom of the V groove of the variable pitch pulley (that is, the meshing means) and the driving force transmitting means (V belt, chain, etc.) meshing with the teeth and transmitting the driving force is obstructed. As a result, the driving force cannot be transmitted and the driving force transmitting means may be damaged.

  An object of the present invention is that the meshing means installed on the shaft of the bottom of the V groove of the pulley does not attack the driving force transmitting means that meshes with the meshing means and transmits the driving force. To provide a continuously variable transmission that does not hinder coordinated movement.

  In the continuously variable transmission according to the present invention, when the speed change region of the continuously variable transmission is at least one of the highest level and the lowest level, the movable meshing portion is in the advanced state with respect to the shaft portion of the pulley, so that the driving force is transmitted. The portion that meshes with the meshed portion of the means and contacts the driving force transmission means of the movable meshing portion is formed in a shape that makes constant the torque reaction force that the driving force transmission means receives from the movable meshing portion.

  According to the present invention, when the speed change region of the continuously variable transmission is at least one of the highest time and the lowest time, the movable meshing portion is advanced with respect to the shaft portion of the pulley, and the meshing force of the driving force transmitting means The portion of the movable meshing portion that contacts the driving force transmission means of the movable meshing portion is formed in a shape that makes the torque reaction force that the driving force transmission means receives from the movable meshing portion constant. The meshing means installed on the shaft does not attack the driving force transmitting means that meshes with the meshing means and transmits the driving force, and does not hinder the coordinated movement of the meshing means and the driving force transmitting means.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic explanatory diagram of a continuously variable transmission according to an embodiment of the present invention. As shown in FIG. 1, the continuously variable transmission (CVT) 10 includes a drive pulley (primary pulley) 11 and a driven pulley (secondary pulley) 12, and a driving force hung between the drive pulley 11 and the driven pulley 12. A movable tooth (movable meshing portion) 16 is attached to a shaft portion (pulley shaft portion) 14 of the driven pulley 12 via a movable tooth fixing component 15.

The CVT 10 is provided in a vehicle, for example, and can change the traveling speed of the vehicle steplessly. In addition, although a belt, a chain, etc. are used as the driving force transmission means 13, the example using a chain as the driving force transmission means 13 is demonstrated here.
A driving force from an engine (not shown) is input to the drive pulley 11, and the driving force output from the driven pulley 12 is transmitted to a driving shaft (not shown). Both the drive pulley 11 and the driven pulley 12 move the movable pulley relative to the fixed pulley to form a V-shaped cross-sectional groove (V groove) between the fixed pulley and the movable pulley and change the V groove width. Can do. Then, by continuously changing the V groove width of the drive pulley 11 which is the driving side and the driven pulley 12 which is the driving side, the transmission pitch of the chain 13 on the driving side and the driving side is changed, Thereby, a smooth stepless speed change can be performed.

FIG. 2 is an explanatory view showing a state where no chain is wound around the pulley shaft portion of FIG. 1. FIG. 3 is an explanatory view showing a state where the chain is wound around the pulley shaft portion of FIG. 1.
As shown in FIGS. 2 and 3, the movable tooth fixing component 15 mounted on the outer peripheral surface of the pulley shaft portion 14 protrudes retreatably from the outer surface of the movable tooth fixing component 15, that is, in a cylindrical shape. A movable tooth 16 is incorporated over the entire circumference of the movable tooth fixing component 15 so as to be movable in the radial direction of the formed movable tooth fixing component 15.

The movable tooth 16 is incorporated in the movable tooth fixing part 15 between the outer surface of the pulley shaft part 14 via a spring member such as a coil spring, for example. At this time, the spring member is in a compressed state. . Therefore, the movable tooth 16 incorporated in the movable tooth fixing component 15 projects the upper end surface 16b surrounded by the inclined surface 16a, which is the upper end side portion of the movable tooth 16, from the outer surface of the movable tooth fixing component 15. Is held in that state.
In place of the coil spring, a ring-shaped spring may be used as a spring member. By mounting the ring-shaped spring on the outer surface of the pulley shaft portion 14 in a reduced diameter state, the spring force at the time of diameter expansion is movable. 16, the movable teeth 16 can protrude outward in the radial direction of the pulley shaft portion 14.

The movable tooth 16 protrudes from the outer surface of the movable tooth fixing part 15 and engages with the chain 13 when the CVT 10 has the highest Hi (for example, overdrive: OD) (see FIG. 2). The movable teeth 16 are not limited to being provided on the pulley shaft portion 14 of the driven pulley 12, but may be provided on the pulley shaft portion 14 of the drive pulley 11. In this case, when the CVT 10 is at the lowest Lo, It protrudes from the outer surface of the movable tooth fixing part 15 and is engaged with the chain 13.
Thus, the movable tooth 16 provided on the pulley shaft portion 14 is at least one of the CVT 10 at the highest time and at the lowest time, that is, the chain 13 as the driving force transmission means is attached to the bottom of the V groove of the pulley. When present, the upper end surface 16 b surrounded by the inclined surface 16 a protruding from the outer surface of the movable tooth fixing component 15 is engaged with the chain 13.

  The chain 13 is formed by, for example, connecting thin chain ring-shaped chain links 17 in an annular shape using a set of two pins 18 and connecting the pins 18 as a connecting shaft. Each of the chain links 17 thus rotated freely (swings) around the pin 18 with the pin 18 as an axis. Each chain link 17 has a recess (engaged portion) cut out at a contact portion of the movable tooth 16 that wraps around the movable tooth 16 in accordance with the protruding shape of the movable tooth 16 from the outer surface of the pulley shaft portion 14. 17a, and the recesses 17a are arranged at a pitch substantially equal to the pitch of the movable teeth 16.

FIG. 4 is an explanatory view showing, in an enlarged manner, a state in which the chain is wound around the pulley shaft portion. As shown in FIG. 4, when the chain 13 is positioned at the bottom of the V groove of the pulley, the chain 13 is attached to the pulley shaft portion 14 and pushed up outward in the shaft portion radial direction by, for example, a coil spring (or ring-shaped spring) ( The movable tooth 16 has an upper end surface 16b surrounded by the inclined surface 16a protruding from the outer surface of the movable tooth fixing component 15.
That is, the movable tooth 16 is engaged with the chain 13 by engaging the protruding upper end side with the recess 17a formed in the chain link 17 of the chain (lock-up chain) 13 as the driving force transmitting means. .

At this time, the movable tooth 16 meshed with the concave portion 17a of the chain 13 has the upper end surface 16b surrounded by the inclined surface 16a positioned at the concave portion 17a of the chain link 17, and the inclined surface 16a is moved to the concave portion 17a. It will be in the state made to contact the opening edge part 17b.
FIG. 5 is an explanatory view showing, in an enlarged manner, the meshing state of the recesses of the chain and the movable teeth in FIG. As shown in FIG. 5, the opening edge 17 b of the recess 17 a of the chain link 17 that contacts the movable tooth 16 intersects with a convex curved surface that bulges toward the movable tooth 16 in a side view, that is, at an obtuse angle. It is formed by a curved surface in which the intersections of the slopes are connected by a semicircular curve. Further, the inclined surface 16a of the movable tooth 16 toward the upper end surface 16b is formed by a concave curved surface that is bored in an arc shape in a side view corresponding to the shape of the opening edge portion 17b.

In other words, at the contact portion where the top of the chevron of the opening edge portion 17b contacts the gentle arc of the inclined surface 16a, the spring reaction force F1 of the spring member by the movable teeth 16 (see the white arrow in the figure) and the chain 13 The rotation direction load F2 from is applied. This rotational load F2 becomes a torque reaction force from the movable tooth 16 to the chain 13.
The convex curved surface of the opening edge portion 17b and the concave curved surface of the inclined surface 16a are not limited to the case where the movable tooth 16 is formed in one rotational direction (see FIG. 5), but are formed in both the rotational directions of the movable tooth 16. Also good.

  FIG. 6 is an explanatory diagram showing the spring reaction force and the rotational load at the contact portion of FIG. As shown in FIG. 6, in the case of the chain (chain 13) and the meshing teeth (movable teeth 16) meshing with the chain as shown in FIG. 5, the torque reaction force that the chain receives from the meshing teeth is the spring of the meshing teeth. It is determined by the force (F1) and the tangent angle θ of the contact point between the chain and the meshing teeth. Therefore, in order to make the torque reaction force (F2) that the chain receives constant, it is necessary to change the tangent angle θ of the contact point (θ1, θ2) according to the amount of movement of the meshing teeth in the axial direction.

  For this reason, in the meshing structure of the chain 13 and the movable teeth 16 according to the present invention, the portion of the movable teeth 16 that contacts the chain 13 has a constant rotational load of the movable teeth 16 (k × x × sin θ × cos θ = constant). ). Here, k: the spring constant of the spring member that applies a load in the radial direction to the movable tooth, x: the amount of movement of the movable tooth in the radial direction, θ: the tangential angle of the position that contacts the chain of the movable tooth, k × x × sin θ × cos θ: a rotational load.

  FIG. 7 is an explanatory view showing an example of the shape of the contact portion of the movable tooth according to the present invention. The gentle arc of the inclined surface 16a that contacts the top of the chevron of the opening edge 17b is between the rotational direction length (mm) of the movable tooth 16 and the axial radial direction length (mm) of the movable tooth 16. 7 is formed from a curve that changes in the relationship shown in FIG. Thereby, the torque reaction force (F2) received by the chain becomes constant.

  Thus, as shown in FIG. 5, a structure having a chain (chain 13) and a tooth (movable tooth 16) meshing with the chain, that is, a recess is provided on the winding side of the link of the chain, and a pulley shaft portion (for example, (Secondary pulley shaft) in the configuration in which teeth that move in the radial direction are arranged and the chain is meshed with the teeth in the shaft portion, if the amount of movement in the radial direction of the shaft portion (movable teeth) differs, The spring reaction force held in the protruding state becomes nonuniform, and the load in the tooth rotation direction received by the teeth becomes nonuniform. For this reason, an excessive load is applied to the teeth, and the durability of the teeth is inevitably lowered.

  Therefore, the torque reaction force in the rotational direction transmitted from the tooth to the chain is constant regardless of the amount of radial movement of the tooth at the site in contact with the tooth chain disposed on the shaft. That is, in the continuously variable transmission according to the present invention, the tangent angle of the contact point between the movable tooth 16 and the chain 13 is changed according to the amount of movement of the movable tooth 16 in the axial portion radial direction. Even when the amount of movement is different, in order to make the rotational load received by the movable teeth 16 meshed with the chain 13 constant, the contact portion of the movable teeth 16 meshed with the chain 13 with the chain 13 is shaped like a chevron of the opening edge 17b. The top portion and the gentle arc of the inclined surface 16a are in contact with each other.

As a result, even if the pitch of the chain 13 meshing with the movable tooth 16 is different, the load in the rotational direction of the movable tooth received by the movable tooth 16 meshing with the chain 13, that is, the torque reaction force received by the chain becomes constant. It can suppress that durability of 16 and the chain 13 falls.
Further, the portion of the movable tooth 16 that contacts the chain 13 has a configuration in which the rotational load of the movable tooth 16 is constant (k × x × sin θ × cos θ = constant), so that an arbitrary spring force or Even in the amount of movement of the shaft radius of the movable tooth 16, it is possible to obtain an effect of suppressing the deterioration of the durability of the movable tooth 16 and the chain 13.

  Thus, in the continuously variable transmission according to the present invention, the meshing means installed on the shaft of the bottom of the V groove of the pulley does not attack the driving force transmitting means that meshes with the meshing means and transmits the driving force. The coordinated movement of the meshing means and the driving force transmitting means is not hindered. In addition, it is possible to prevent the durability of the movable teeth 16 and the chain 13 from decreasing.

It is a schematic explanatory drawing of the continuously variable transmission which concerns on one embodiment of this invention. It is explanatory drawing which shows the state in which the chain is not wound around the pulley axial part of FIG. It is explanatory drawing which shows the state in which the chain is wound around the pulley axial part of FIG. It is explanatory drawing which expands and shows the state in which the chain is wound around the pulley shaft part. It is explanatory drawing which expands and shows the meshing state of the recessed part of a chain in FIG. 4, and a movable tooth. It is explanatory drawing shown about the spring reaction force and rotation direction load in the contact part of FIG. It is explanatory drawing which shows an example of the contact part shape of the movable tooth which concerns on this invention.

Explanation of symbols

10 CVT
11 Drive pulley 12 Driven pulley 13 Chain (drive force transmission means)
14 Shaft portion 15 Movable tooth fixed part 16 Movable tooth 16a Inclined surface 16b Upper end surface 17 Chain link 17a Recessed portion 17b Opening edge portion 18 Pin F1 Spring reaction force F2 Rotational load θ Tangential angle

Claims (3)

In the continuously variable transmission that transmits the rotational driving force of one pulley to the other pulley by the driving force transmitting means that is hung between two pulleys that can both change the pulley groove width.
A meshed portion provided on a pulley winding side of the driving force transmitting means;
It is installed on the shaft of the pulley so as to be movable in the shaft radial direction so that it can move forward and backward with respect to the shaft. When the speed change region is at least one of Hi and Lo, A movable meshing portion that can mesh with the meshing portion;
Regardless of the amount of movement of the movable mesh portion in the radial direction of the shaft, the torque reaction force that the drive force transmission device receives from the movable mesh portion is made constant at the portion of the movable mesh portion that contacts the drive force transmission device. A continuously variable transmission characterized by being formed into a shape.   The portion of the movable meshing portion that comes into contact with the driving force transmitting means is formed by a gentle arc that forms a top of a chevron that changes the tangential angle of the contact point according to the amount of radial movement of the movable meshing portion. The continuously variable transmission according to claim 1, wherein: The portion of the movable meshing portion that comes into contact with the driving force transmitting means is
The spring constant of the spring that sets the movable meshing portion in the advanced state is k, the radial movement amount of the movable meshing portion is x, the tangent angle of the position of the movable meshing portion in contact with the driving force transmitting means is θ, and the movable The rotation direction load of the meshing portion is k × x × sin θ × cos θ,
The continuously variable transmission according to claim 2, wherein the continuously variable transmission has a shape of k × x × sin θ × cos θ = constant.

Images