WO2017065246A1

WO2017065246A1 - Continuously variable transmission

Info

Publication number: WO2017065246A1
Application number: PCT/JP2016/080455
Authority: WO
Inventors: 忠明平岡; 洋一辻; 智滋大畑
Original assignee: ジヤトコ株式会社
Priority date: 2015-10-16
Filing date: 2016-10-14
Publication date: 2017-04-20
Also published as: JP2017075676A

Abstract

Provided is a continuously variable transmission in which a chain (4) wound into a groove between a fixed pulley (31) and a movable pulley (32) comprises: a plurality of link rows (41) configured from a plurality of link plates (42); and a link pin (43) that connects the plurality of link plates (42). The pulley shaft (31A) of the fixed pulley (31) comprises an enlarged diameter section (31b) that is a curved surface and in which the diameter gradually increases as proximity to a first sheave surface (31a) increases. The link rows (41) are arranged at a position that does not overlap with the enlarged diameter section (31b) when the winding diameter of the chain (4) is at a minimum and said link rows (41) are viewed from the radial direction (R) of the pulley shaft (31A).

Description

Continuously variable transmission

The present invention relates to a continuously variable transmission having a fixed pulley, a movable pulley, and a chain sandwiched between these pulleys.

Conventionally, continuously variable transmissions capable of continuously changing the gear ratio have been put to practical use as, for example, vehicle transmissions.

In a continuously variable transmission, an endless belt such as a belt or a chain is wound around a primary pulley and a secondary pulley, and a thrust applied to a movable pulley of the primary pulley and the secondary pulley causes Power is transmitted using the friction force generated between them.

In such a continuously variable transmission, generally, a groove with an R-shaped cross section is formed in the circumferential direction at the root portion of the sheave of the fixed pulley (the portion where the sheave surface of the fixed pulley rises from the pulley shaft) ( For example, Patent Document 1). Hereinafter, this groove is referred to as an R escape groove.

This R relief groove is formed by forming an R shape as a recess to relieve stress concentration on the root of the sheave.

¡If the endless belt and the sheave root of the fixed pulley interfere with each other, the endless belt or the sheave root may be damaged.

Therefore, by making the R shape a recess, when the endless belt is close to the pulley shaft as the winding diameter of the pulley decreases according to the gear ratio, the R shape does not interfere with the endless belt. ing.

However, when the R clearance groove is formed, the sheave root becomes thinner by the depth of the R clearance groove, and the strength of the pulley shaft decreases.

It is conceivable that this decrease in strength can be offset by increasing the diameter of the pulley shaft. However, if the diameter of the pulley shaft is increased, the minimum winding diameter of the endless belt increases and the ratio coverage (= gear ratio) is increased. (Change width) becomes narrow.

Japanese Patent Laying-Open No. 2005-003012 (see FIG. 2)

The present invention was devised in view of the problems as described above, and while mitigating stress concentration of the fixed pulley, it is possible to improve the strength of the pulley shaft and to increase the ratio coverage as compared with the prior art. An object of the present invention is to provide a continuously variable transmission.

(1) In order to achieve the above object, a continuously variable transmission according to the present invention includes a fixed pulley having a pulley shaft and a first sheave surface, a movable pulley having a second sheave surface, the fixed pulley, and the movable pulley. A continuously variable transmission having a chain wound around a groove between the pulley and the chain, wherein the chain includes a plurality of link rows formed of a plurality of link plates arranged in a width direction of the chain; A link pin that connects a plurality of link plates, and the pulley shaft of the fixed pulley has an enlarged diameter portion that is a curved surface that gradually increases in diameter as it approaches the first sheave surface, When viewed from the radial direction of the pulley shaft when the winding diameter of the chain is minimized, the chain is disposed at a position that does not overlap the enlarged diameter portion.

(2) It is preferable to have a restricting means for restricting movement of the link row to the enlarged diameter portion side.

(3) It is preferable that the restricting means is a retainer pin attached to the link pin, and the retainer pin is located between the link row and the first sheave surface.

(4) It is preferable that a large number of the link plates are arranged between the center line and the movable pulley rather than between the center line in the width direction of the chain and the fixed pulley.

According to the continuously variable transmission of the present invention, the pulley shaft of the fixed pulley has the enlarged portion that is a curved surface whose diameter gradually increases as it approaches the first sheave surface. Improve the shaft strength and reduce the concentration of the stress on the pulley shaft by the curved surface of the enlarged diameter part to improve the strength of the pulley shaft than before. The ratio coverage can be increased by reducing the hook diameter.

In addition, the link row is arranged at a position that does not overlap the enlarged diameter part when viewed from the radial direction of the pulley shaft when the chain winding diameter is minimized, so that the chain winding diameter is minimum. Thus, even when the link row is closest to the enlarged diameter portion, interference between the link row and the enlarged diameter portion can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the structure of the principal part of the continuously variable transmission as one Embodiment of this invention, (a) is the side view, (b) is the longitudinal cross-sectional view which expanded the principal part of the secondary pulley. is there. It is sectional drawing which shows typically each principal part of the secondary pulley and chain which concern on one Embodiment of this invention, and is the X section enlarged view of FIG.1 (b). It is a side view which shows typically each principal part of the secondary pulley and chain which concern on one Embodiment of this invention. It is a front view which shows typically the principal part of the chain which concerns on one Embodiment of this invention. It is a perspective view showing typically the composition of the link board concerning one embodiment of the present invention. It is sectional drawing which shows typically each principal part of the secondary pulley and chain of one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Note that the embodiment described below is merely an example, and there is no intention of excluding various modifications and application of technology that are not explicitly described in the following embodiment.

The configurations of the following embodiments can be implemented with various modifications without departing from the spirit thereof, can be selected as necessary, or can be appropriately combined.

Note that the inner peripheral side in the present invention refers to the inner side in the radial direction of the pulley shaft. In other words, when the part of the primary pulley or the part of the chain wound around the primary pulley is referred to as the inner peripheral side, the inner side in the radial direction of the primary shaft means the secondary pulley or the chain wrapped around the secondary pulley. When referring to the inner peripheral side of the part, it refers to the inner side in the radial direction of the secondary shaft.

Similarly, the outer peripheral side in the present invention means the outer side in the radial direction of the pulley shaft. In other words, in the case of the outer peripheral side of the primary pulley part or the chain part wound around the primary pulley, the outer side in the radial direction of the primary shaft means the secondary pulley or the part of the chain wound around the secondary pulley. Is the outer side in the radial direction of the secondary shaft.

[1. Main components of continuously variable transmission]
A configuration of a main part of a continuously variable transmission as an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic diagram showing a configuration of a main part of a continuously variable transmission as an embodiment of the present invention, where (a) is a side view thereof and (b) is an enlarged main part of a secondary pulley. It is a longitudinal cross-sectional view. 1 (a) and 1 (b), the chain 4 is shown by simplifying only the track thereof by a one-dot chain line.

As shown in FIG. 1 (a), a continuously variable transmission (hereinafter also referred to as CVT) 1 includes an endless pulley wound around a primary pulley 2, a secondary pulley 3, and these primary pulley 2 and secondary pulley 3. A belt-like chain 4 is provided.

The primary pulley 2 has a primary shaft (pulley shaft) 21A, and the primary shaft 21A is connected to an engine (not shown) via a torque converter (not shown).

The secondary pulley 3 has a secondary shaft (pulley shaft) 31A disposed in parallel with the primary shaft 21A. The secondary shaft 31A is connected to a driving wheel (not shown) via a speed reduction mechanism, a differential mechanism, etc. (not shown). It is connected.

As shown in FIG. 1 (b), the secondary pulley 3 includes a fixed pulley 31 and a movable pulley 32 disposed to face the fixed pulley 31.

The fixed pulley 31 includes the secondary shaft 31A and a fixed pulley main body 31B fixed to the secondary shaft 31A.

The movable pulley 32 is provided so as to be locked in the rotational direction with respect to the secondary shaft 31A and movable in the axial direction A of the secondary shaft 31A.

The sheave surface (first sheave surface) 31a of the fixed pulley 31 that faces each other and the sheave surface (second sheave surface) 32a of the movable pulley 32 are gradually spaced from each other toward the outer peripheral side (radially outward). A V-shaped groove having a V-shaped cross section is formed between the sheave surface 31a and the sheave surface 32a.

Although not shown, the primary pulley 2 includes a fixed pulley and a movable pulley disposed to face the fixed pulley, like the secondary pulley 3. The fixed pulley includes the primary shaft 21A and the primary pulley. The movable pulley is provided so as to be locked to the primary shaft 21A in the rotational direction and movable in the axial direction A of the primary shaft 21A.

The sheave surface of the fixed pulley and the sheave surface of the movable pulley that are opposed to each other of the primary pulley 2 are formed in a conical shape in which the mutual distance gradually increases toward the outer peripheral side, and the sheave surface of the fixed pulley and the sheave of the movable pulley A V-shaped groove having a V-shaped cross section is formed between the surface and the surface.

The position of the movable pulley 32 of the primary pulley 2 and the movable pulley 32 of the secondary pulley 3 is controlled by a hydraulic actuator (not shown). As a result, the width of the V-groove changes, the contact radius (winding diameter) between the chain 4 and the sheave surface 31a and the sheave surface 32a changes, and the gear ratio changes.

[2. Detailed configuration of fixed pulley and chain]
A detailed configuration of the fixed pulley and the chain of the secondary pulley according to the embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a schematic diagram showing the configuration of the main parts of the secondary pulley and the chain in a state where the gear ratio according to the embodiment of the present invention is the highest (that is, a state where the winding diameter of the chain on the secondary pulley is minimum). 4 is a cross-sectional view taken along the line EE of FIG. 4 (however, the hatch indicating the cross section of the link plate 42 is omitted), and is an enlarged view of a portion X in FIG.

FIG. 3 is a side view schematically showing the main parts of the secondary pulley and the chain in the state where the gear ratio is the highest according to one embodiment of the present invention.

FIG. 4 is a front view schematically showing the main part of the chain according to one embodiment of the present invention.

FIG. 5 is a perspective view schematically showing a configuration of a link plate according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view schematically showing main parts of the secondary pulley and the chain according to the embodiment of the present invention, and is a view showing a state where the gear ratio is on the low side as compared with FIG.

Since the fixed pulley of the primary pulley 2 and the fixed pulley 31 of the secondary pulley 3 are configured in the same manner as described above, the fixed pulley 31 of the secondary pulley 3 will be described as an example.

As shown in FIG. 2 with halftone dots, at the root of the sheave surface 31a of the fixed pulley 31, the secondary shaft 31A gradually increases in diameter as it approaches the sheave surface 31a, and extends over the entire length of the secondary shaft 31A. It has an enlarged diameter portion 31b that is larger than the diameter D of the other portion.

The dashed-dotted line in FIG. 2 has shown the virtual extended surface which extended linearly the outer peripheral surface of the part except the sheave surface 31a and the diameter-expanded part 31b of the secondary shaft 31A, and it is outside this extended surface. Is defined as the enlarged diameter portion 31b.

The enlarged diameter portion 31b is provided over the entire circumference of the secondary shaft 31A. The enlarged-diameter portion 31b has a constant cross-sectional shape, and the outer edge of the cross-section smoothly connects the sheave surface 31a of the fixed pulley 31 and the outer peripheral surface of the secondary shaft 31A, and the secondary shaft 31A and the sheave surface 31a. It has an R shape (arc shape) slightly recessed to the side.

In other words, the secondary shaft 31A is provided with an R at the base of the fixed pulley 31 (an R curved surface is formed). Since the secondary shaft 31A tends to concentrate stress at the base of the fixed pulley 31, the stress concentration is reduced by attaching R to the base.

The chain 4 is configured as shown in FIGS.
That is, the chain 4 is configured in an endless manner by connecting a plurality of link plates 42 along a chain traveling direction C orthogonal to the axial direction A, but the axial direction (hereinafter referred to as the chain width direction or simply the width direction). A) A plurality of link plates 42 are also provided in A to form a belt shape so that a large force can be transmitted.

Each link plate 42 is connected by inserting a link pin 43 extending in the axial direction A as will be described later. In order to simultaneously connect the link plates 42 arranged in the chain width direction A and the chain travel direction C by the link pins 43, the link plates 42 are overlapped in the chain travel direction C and the chain width direction A (that is, The end portions of the link plates 42 are arranged so as to overlap each other.

Here, at the same phase position in the chain traveling direction C, the plurality of link plates 42 are arranged side by side in the chain width direction A. Hereinafter, the row (row) of the plurality of link plates 42 arranged side by side in this way is The description will be given by defining the link row 41A and the link row 41B.

In FIG. 4, the number of link plates 42 constituting the link row 41 </ b> A and the link row 41 </ b> B is shown as a smaller number than in FIG. 2 for convenience.

Hereinafter, the link row 41A and the link row 41B will be referred to as the link row 41 when they are not particularly distinguished.

Specifically, as shown in FIGS. 3 and 4, the link row 41A and the link row 41B adjacent to each other in the traveling direction C of the chain 4 are connected, and the link pin 43 is connected to the link plate 42 constituting the link row 41A and the link row 41B. Connect by inserting.

That is, one end of the opening 42a of the link plate 42 of the link row 41A overlaps with the other end of the opening 42a of the link plate 42 of the link row 41B adjacent to one end side of the link row 41A, and the link of the link row 41A. The other end of the opening 42a of the plate 42 and the one end of the opening 42a of the link plate 42 of the link row 41B adjacent to the other end side of the link row 41A are arranged in an overlapping manner.

Therefore, at both ends of the opening 42a of the link plate 42, overlapping portions with the opening 42a of the adjacent link plate 42 are locations where the pair of link pins 43 are respectively inserted (that is, the openings 41a of the link row 41). The pair of link pins 43 are respectively inserted into the openings 41a, whereby the link row 41A and the link row 41B are connected to each other in a bendable manner to form the chain 4.

Each of the pair of link pins 43 has a curved back surface 43a, and the curved back surface 43a is back-to-back, and is inserted through the opening 41a.

As shown in FIG. 2, both end surfaces 43b of the link pin 43 are formed as inclined surfaces corresponding to the inclination of the sheave surface 31a and the sheave surface 32a so as to make frictional contact with the sheave surface 31a and the sheave surface 32a, respectively. .

As shown in FIG. 5, the link plate 42 is formed with the opening 42a through which the link pin 43 is inserted, and the plurality of link plates 42 have the link pin 43 inserted through the openings 42a. Thus, they are bundled in the link row 41.

The opening 41a through which the link pin 43 is inserted to connect adjacent link rows 41 is formed at both ends of each opening 42a by arranging a plurality of openings 42a of the link plate 42 in the chain width direction A. Has been.

That is, the link pin 43 bundles the link plates 42 arranged in the chain width direction A to form the link row 41 and simultaneously connects the link row 41 arranged in the traveling direction C to form the chain 4.

As shown in FIGS. 2 and 4, on the peripheral surface of each link pin 43, a retainer pin 44 (regulating means) is fixed between the link row 41 and the sheave surface 31 a of the fixed pulley 31. And a retainer pin 45 is fixed between the sheave surface 32 a of the movable pulley 32.

The plurality of link plates 42 inserted into the link pin 43 are prevented from being detached from the link pin 43 by the retainer pin 44 and the retainer pin 45. That is, the link plate 42 is restricted from moving toward the fixed pulley 31 by the retainer pin 44 and is restricted from moving toward the movable pulley 32 by the retainer pin 45. In other words, the installation range B of the link plate 42 is defined by the retainer pin 44 and the retainer pin 45.

Here, the arrangement of the retainer pins 44, which is a major feature of the present invention, will be described.
As shown in FIG. 2, when the link row 41 is viewed from the radial direction R of the secondary shaft 31 </ b> A when the winding diameter of the chain 4 is the minimum, the link row 41 is arranged only at a position that does not overlap the enlarged diameter portion 31 b. As shown, a retainer pin 44 is disposed.

Specifically, when the winding diameter of the chain 4 is minimum, the retainer pin 44 has a portion 44a closest to the link plate 42 on the side of the movable pulley 32 (from the enlarged diameter portion 31b) by ΔA from the enlarged diameter portion 31b. It is arranged so that it is located on the side to be separated.

With such an arrangement of the retainer pins 44, even when the gear ratio is the highest and the winding diameter of the chain 4 around the secondary pulley 3 is minimized and the link plate 42 is closest to the enlarged diameter portion 31b, The interval between the inner peripheral end (lower end in FIG. 2) of the link plate 42 and the enlarged diameter portion 31b is maintained, and interference between the link plate 42 and the enlarged diameter portion 31b is prevented.

Note that the winding diameter of the chain 4 around the primary pulley 2 is the lowest at the lowest gear ratio.

In the state where the gear ratio is not the highest and the winding diameter of the chain 4 around the secondary pulley 3 is not the minimum, the link row 41 has an enlarged portion when viewed from the radial direction R as shown in FIG. It may overlap with 31b. That is, in the state shown in FIG. 6, the link row 41 is separated from the enlarged diameter portion 31b in the radial direction R. Therefore, even if it overlaps with the enlarged diameter portion 31b when viewed from the radial direction R, the enlarged diameter portion. It does not interfere with 31b.

In addition, the installation range B of the link plate 42 is divided into a range B1 and a range B2 with the center line CL in the width direction A of the chain 4 as a boundary, and the range B1 between the center line CL and the movable pulley 32 is Is arranged to be larger than the range B2 between the center line CL and the fixed pulley 31.

Thereby, a large number of link plates 42 are arranged on the movable pulley 32 side rather than the fixed pulley 31 side, with the center line CL as a boundary.

It should be noted that the strength of the chain 4 is maintained at the same level as before by setting the number of link plates 42 constituting one link row 41 to the same number as before.

Further, as shown in FIG. 2, even when the winding diameter of the chain 4 is minimized and the link plate 42 is closest to the enlarged diameter portion 31b, the link pin 43 is separated in the radial direction R from the enlarged diameter portion 31b. is doing. In other words, the height (dimension in the radial direction R) of the enlarged diameter portion 31b is set so as not to interfere with the link pin 43 even when the winding diameter of the chain 4 is minimized.

[3. Action / Effect]
Since the number of link plates 42 constituting one link row 41 and the width of the chain 4 are the same as the conventional one, the retainer pin 44 is separated from the sheave surface 31a so as to be separated from the enlarged diameter portion 31b. Although the width dimension is slightly increased, the continuously variable transmission according to the embodiment of the present invention has the following great advantages.

(1) In the continuously variable transmission according to the embodiment of the present invention, the secondary shaft 31A is provided with an enlarged diameter portion 31b at the root of the sheave surface 31a of the fixed pulley 31.

Thereby, compared with the conventional configuration in which the R clearance groove is provided at the root of the sheave surface 31a, the secondary shaft 31A is thicker at the root of the sheave surface 31a than the other portions due to the presence of the enlarged diameter portion 31b. When the diameter of the secondary shaft 31A is the same, the strength of the secondary shaft 31A is improved as compared with the conventional configuration.

Further, when the strength of the secondary shaft 31A is equal to that of the conventional configuration, the secondary shaft 31A can be made thinner than the conventional configuration, and as a result, the minimum winding diameter of the chain can be made smaller than the conventional configuration.

Furthermore, since the diameter-expanded portion 31b is formed in a smooth R-curved surface whose diameter gradually increases as the sheave surface 31a of the fixed pulley 31 is approached, the concentration of stress on the root of the fixed pulley 31 can be reduced.

As shown by a two-dot chain line in FIG. 2, the R clearance groove 31c employed in the conventional structure has a shape that rises after sinking to the center side of the secondary pulley shaft 31A, and therefore the bottom 31d of the R clearance groove 31c. In this case, the curvature increases and stress tends to concentrate.
On the other hand, since the enlarged diameter portion 31b does not sink to the center side of the secondary pulley shaft 31A, the overall curvature is small, and the stress can be more effectively distributed compared to the R escape groove 31c. Can do.

Therefore, according to the continuously variable transmission according to one embodiment of the present invention, the presence of the enlarged diameter portion 31b improves the strength of the secondary shaft 31A and reduces the concentration of stress on the root of the fixed pulley 31. In addition, it is possible to increase the ratio coverage by improving the strength of the secondary shaft 31A or by reducing the minimum winding diameter of the chain 4 as compared with the related art.

Further, by restricting the movement of the link row 41 toward the enlarged diameter portion 31b by the retainer pin 44, the link row 41 can be used as the secondary shaft even when the winding diameter of the chain 4 on the secondary pulley 3 is minimized. When viewed from the radial direction R of 31A, it is arranged at a position that does not overlap with the enlarged diameter portion 31b (in other words, even when the winding diameter of the chain 4 on the secondary pulley 3 is minimized, the link The installation range B of the row 41 with respect to the chain width direction A is limited to a range in which the link row 41 and the enlarged diameter portion 31b do not interfere with each other).
Therefore, even when the winding diameter of the chain 4 is minimized and the link row 41 is closest to the enlarged diameter portion 31b, interference between the link row 41 and the enlarged diameter portion 31b can be prevented.

(2) Furthermore, by arranging a large number of link plates 42 in the range B1 on the movable pulley 32a side rather than the range B2 on the fixed pulley 41 side, the same number of link plates 42 are arranged in the range B1 and the range B2. In addition, the strength of the chain 4 can be improved by increasing the number of link plates 42 constituting one link row 41.

This is due to the following reason. In the configuration shown in FIG. 2, if the link plates 42 are set to the same number in the range B1 and the range B2, the retainer pin 45 on the movable pulley 32a side must be shifted to the center line CL side to reduce the range B1. The number of link plates 42 per row 41 is reduced.

If the range B1 and the range B2 are the same size, the chain 4 can be left-right symmetric (symmetric with respect to the center line CL), and either one of the left and right end faces 43b of the link pin 43 faces the enlarged diameter portion 31b. Although the chain 4 can be wound around the secondary pulley 3, one link row 41 can be obtained by adopting the configuration shown in FIG. 2 (a configuration in which more link plates 42 are arranged in the range B1 than in the range B2). The strength of the chain 4 can be improved by increasing the number of hitting link plates 42.

Since the primary pulley 2 is configured in the same manner as the secondary pulley 3 as described above, the operations and effects (1) to (3) described above can also be obtained for the primary pulley 2.

[4. Others]
In the above embodiment, the example in which the enlarged diameter portion and the regulating means of the present invention are applied to both the primary pulley 2 and the secondary pulley 3 has been described, but the expansion of the present invention is applied only to at least one of the primary pulley 2 and the secondary pulley 3. You may apply a diameter part and a control means.

(2) In the above embodiment, the restricting means for restricting the movement of the link plate 42 toward the enlarged diameter portion 31b is configured by the retainer pin 44. However, if the restricting means can restrict the movement of the link plate 42, The shape of the pin is not limited to that of the retainer pin 44.

For example, the restricting means may be constituted by an annular convex portion formed over the entire circumference of the link pin 43.

Claims

A fixed pulley having a pulley shaft and a first sheave surface;
A movable pulley having a second sheave surface;
A continuously variable transmission having a chain wound around a groove between the fixed pulley and the movable pulley;
The chain has a link row composed of a plurality of link plates arranged in the width direction of the chain, and a link pin that connects the plurality of link plates,
The pulley shaft of the fixed pulley has a diameter-expanded portion that is a curved surface whose diameter gradually increases as it approaches the first sheave surface,
The link train is a continuously variable transmission that is disposed at a position that does not overlap the enlarged diameter portion when viewed from the radial direction of the pulley shaft when the chain winding diameter is minimized.
The continuously variable transmission according to claim 1, further comprising a restricting means for restricting movement of the link row to the enlarged diameter portion side.
The restricting means is a retainer pin attached to the link pin,
The continuously variable transmission according to claim 2, wherein the retainer pin is located between the link row and the first sheave surface.
The link plate is arranged between the center line and the movable pulley rather than between the center line in the width direction of the chain and the fixed pulley. The continuously variable transmission described in 1.