CN103968026A - Vehicle power transmission apparatus - Google Patents

Abstract

The present invention provides a power transmission device for a vehicle. While suppressing the weight increase of the connecting rod of the vehicle power transmission device to a minimum, the roundness of the bearing press-fitted into the large end of the connecting rod is ensured. The connecting part (19c) of the connecting rod (19) is formed with a through hole (19d) penetrating through both surfaces in the axial direction, and the center (Ob) of the outer peripheral surface (Pb) of the large end part (19a) is opposite to the inner peripheral surface ( The center (Oa) of Pa) is eccentric to the side of the small end (19b), and the inner edge (Ea) of the through hole facing the large end is a circular arc with the same center as the outer peripheral surface. Therefore, by preventing the large end The rigidity of the bearing changes sharply in the circumferential direction, so that the press-in reaction force changes smoothly in the circumferential direction, thereby improving the roundness of the bearing (20). Furthermore, compared with the case where the roundness of the bearing is improved by forming the large end portion as a whole thick, the increase in the weight and size of the connecting rod can be suppressed to a minimum.

Description

Vehicle power transmission device

technical field

The present invention relates to a vehicle power transmission device provided with a crankshaft type continuously variable transmission that transmits driving force from an input shaft to an output shaft via a reciprocating connecting rod and a one-way clutch.

Background technique

According to the following Patent Document 1, there is known a power transmission device for a vehicle in which a large end portion of a connecting rod is connected to an eccentric disk that rotates integrally with an input shaft connected to the engine, and a small end portion of the connecting rod is connected to It is connected with the output shaft through the one-way clutch, and the reciprocating motion of the connecting rod generated by the eccentric rotation of the eccentric disc is converted into the rotary motion of the output shaft in one direction by using the one-way clutch.

Patent Document 1: Japanese PCT Publication No. 2005-502543

However, in the above-mentioned conventional vehicle power transmission device, the inner ring of the ball bearing is pressed into the outer peripheral surface of the eccentric disk provided on the input shaft, and the inner peripheral surface of the large end portion of the connecting rod is pressed into the outer peripheral surface of the ball bearing. outer ring. Since the link has a connecting portion connecting the large end and the small end, the rigidity of the large end of the link is not constant in the circumferential direction, and the rigidity of the portion connected to the connecting portion becomes locally high. Therefore, when the large end of the connecting rod is pressed into the outer ring of the ball bearing, the outer ring in contact with the relatively rigid part of the large end receives a large press-fit reaction force, and the rigidity of the large end is low. The partially contacted outer ring receives a small press-in reaction force, and the difference in the press-in reaction force causes the ball bearing to deform and reduce the roundness, resulting in problems such as increased friction or reduced durability of the ball bearing.

In order to avoid such a problem, it is sufficient to increase the thickness of the large end portion of the connecting rod as a whole to increase the rigidity, but doing so has the problem of increasing the weight and size of the connecting rod.

Contents of the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to ensure the roundness of a bearing press-fitted into a large end portion of the connecting rod while minimizing the increase in weight of a connecting rod of a power transmission device for a vehicle.

In order to achieve the above object, according to the invention described in claim 1, there is provided a power transmission device for a vehicle, the power transmission device for a vehicle includes: an input shaft connected to a drive source; an output shaft parallel to the input shaft a ground arrangement; a swing link supported by the output shaft in a swingable manner; a one-way clutch arranged between the output shaft and the swing link, and when the swing link swings in one direction the one-way clutch engages and disengages when the oscillating link swings in the other direction; the eccentric disc rotates eccentrically integrally with the input shaft; the variable speed actuator alters the eccentric an eccentric amount of a disk; and a connecting rod connecting the eccentric disk and the swing link, the power transmission device for a vehicle is characterized in that the connecting rod has an annular large end portion pressed into to a bearing provided on the outer peripheral surface of the eccentric disk; a small end portion, which is connected to the swing link; and a connecting portion, which connects the large end portion and the small end portion, at the connecting portion A through hole penetrating both surfaces in the axial direction is formed, the center of the outer peripheral surface of the large end portion is eccentric to the small end portion side with respect to the center of the inner peripheral surface, and the center of the through hole facing the large end portion The inner edge portion is a circular arc having a center together with the outer peripheral surface.

In addition, according to the invention described in claim 2, there is provided a power transmission device for a vehicle, wherein, in addition to the structure of claim 1, the radius of the inner edge of the through hole is larger than that of the large end. The radius of the outer peripheral surface is small.

In addition, according to the invention described in claim 3, there is provided a power transmission device for a vehicle, wherein, in addition to the structure of claim 1 or 2, the outer edge of the through hole and the large The outer peripheral surfaces of the ends are connected in a tangential line.

In addition, the ball bearing 20 of the embodiment corresponds to the bearing of the present invention, and the engine E of the embodiment corresponds to the drive source of the present invention.

According to the structure of claim 1, when the input shaft connected to the drive source rotates, the connecting rod whose large end is connected to the eccentric disc integrally rotated eccentrically with the input shaft reciprocates, and the small end connected to the connecting rod swings The chain link swings back and forth. When the swing link swings in one direction, the one-way clutch is engaged, and when the swing link swings in the other direction, the one-way clutch is disengaged, so the reciprocating motion of the connecting rod is converted into a rotational motion of the output shaft in one direction . When the eccentricity of the eccentric disk is changed by the speed change actuator, the stroke of the reciprocating motion of the connecting rod is changed to change the swing angle of the swing link. Therefore, the rotation of the input shaft is transmitted to the output shaft after the speed is changed.

The connecting rod includes: an annular large end portion press-fitted into a bearing provided on the outer peripheral surface of the eccentric disk; a small end portion connected to the swing link; and a connecting portion connecting the large end portion and the small end portion. Therefore, the rigidity of the large end portion of the connecting rod becomes locally high at the portion connected to the connecting portion, and when the large end portion of the connecting rod is pressed into the bearing, there is a possibility that the Equalization deflects the bearing, resulting in loss of roundness.

Moreover, a through hole penetrating both surfaces in the axial direction is formed at the connecting portion of the connecting rod, the center of the outer peripheral surface of the large end is eccentric to the small end side with respect to the center of the inner peripheral surface, and the through hole faces the large end. The inner edge of the bearing is a circular arc with the same center as the outer peripheral surface. Therefore, by preventing the rigidity of the large end from changing rapidly in the circumferential direction, the press-fit reaction force can be smoothly changed in the circumferential direction, thereby improving the roundness of the bearing. . Furthermore, compared with the case where the roundness of the bearing is improved by forming the large end portion as a whole thick, it is possible to minimize the increase in the weight and size of the connecting rod.

In addition, according to the structure of claim 2, since the radius of the inner edge portion of the through hole is smaller than the radius of the outer peripheral surface of the large end portion, by reducing the radius of the inner edge portion of the through hole, it is possible to reduce the distance between the connecting portion and the connecting portion. The rigidity of the large end portion which becomes excessively large at a portion can make the rigidity of the large end portion uniform in the circumferential direction to further improve the roundness of the bearing.

In addition, according to the structure of claim 3, since the outer edge portion of the through hole is connected tangentially to the outer peripheral surface of the large end portion, it is possible to reduce the thickness of the connecting rod at the portion where the large end portion and the connecting portion are connected. Minimizing variation enables the press-fit reaction force received by the bearing from the large end to be more uniform in the circumferential direction, thereby further improving the roundness of the bearing.

Description of drawings

FIG. 1 is a schematic diagram of a power transmission device for a vehicle.

Fig. 2 is a detailed view of two parts in Fig. 1 .

Fig. 3 is a sectional view taken along line 3-3 of Fig. 2 (TOP state).

Fig. 4 is a sectional view taken along line 3-3 in Fig. 2 (LOW state).

Fig. 5 is an action explanatory diagram in the highest state.

Fig. 6 is an explanatory diagram of operation in the lowest state.

Fig. 7 is a diagram showing the shape of a link.

FIG. 8 is a diagram comparing the roundness of large end portions of the embodiment and Comparative Examples 1 to 3. FIG.

9 is a graph comparing the roundness of the large end portion of the embodiment and Comparative Example 4. FIG.

FIG. 10 is a graph comparing the embodiment and Comparative Example 5. FIG.

Label description

11: input shaft;

12: output shaft;

13: Swing link;

14: variable speed actuator;

18: eccentric disc;

19: connecting rod;

19a: big end;

19b: small end;

19c: connecting portion;

19d: through holes;

20: ball bearing (bearing);

21: one-way clutch;

E: engine (drive source);

Ea: the inner edge of the through hole;

Eb: the outer edge of the joint;

Oa: the center of the inner peripheral surface of the large end;

Ob: the center of the outer peripheral surface of the large end;

Pa: the inner peripheral surface of the large end;

Pb: the outer peripheral surface of the big end;

Rb: the radius of the outer peripheral surface of the large end;

Rc: Radius of the inner edge of the through hole.

Detailed ways

Next, an embodiment of the present invention will be described based on FIGS. 1 to 10 .

As shown in FIG. 1 , a power transmission device for a vehicle that transmits driving force of an engine E to drive wheels W, W via left and right axle shafts 10 , 10 includes a crank-type continuously variable transmission T and a differential D.

Next, the configuration of the continuously variable transmission T will be described based on FIGS. 2 to 6 .

As shown in FIG. 2 and FIG. 3 , the continuously variable transmission T of this embodiment is formed by overlapping a plurality of (four in the embodiment) power transmission units U... having the same structure in the axial direction. The units U... include a common input shaft 11 and a common output shaft 12 arranged in parallel, and the rotation of the input shaft 11 is decelerated or accelerated and then transmitted to the output shaft 12 .

Hereinafter, the configuration of one power transmission unit U will be described as a representative one. The input shaft 11 rotatably connected to the engine E penetrates a hollow rotary shaft 14 a of a transmission actuator 14 such as an electric motor so as to be relatively rotatable. The rotor 14b of the shift actuator 14 is fixed to the rotating shaft 14a, and the stator 14c is fixed to the housing. The rotary shaft 14 a of the shift actuator 14 is rotatable at the same speed as the input shaft 11 , and is relatively rotatable at a different speed with respect to the input shaft 11 .

A first pinion 15 is fixed to the input shaft 11 passing through the rotation shaft 14 a of the transmission actuator 14 , and a crankshaft-shaped carrier 16 is connected to the rotation shaft of the transmission actuator 14 so as to straddle the first pinion 15 . 14a. Two second pinion gears 17, 17 having the same diameter as the first pinion gear 15 are respectively supported by pinion pins 16a, 16a at positions forming an equilateral triangle in cooperation with the first pinion gear 15, and the ring gear 18a and these first pinion gears The pinion gear 15 meshes with the second pinion gears 17 , 17 , and the ring gear 18 a is eccentrically formed inside a disk-shaped eccentric disk 18 .

The link 19 includes a large end portion 19a, a small end portion 19b, and a connecting portion 19c that connects the large end portion 19a and the small end portion 19b. The large end portion 19a is relatively rotatably fitted to the outer periphery of the eccentric disk 18 via a ball bearing 20, and the small end portion 19b is pivotally supported by a swing link 13 via a pin 26, and the swing link 13 is supported in a swingable manner. on the outer circumference of the output shaft 12.

The one-way clutch 21 disposed between the output shaft 12 and the swing link 13 includes: an annular outer member 22 pressed into the inner peripheral surface of the swing link 13; inside and fixed to the output shaft 12 ; and rollers 25 .

It can be clearly seen from FIG. 2 that the four power transmission units U... have a crankshaft-shaped planetary carrier 16 in common, and the phases of the eccentric discs 18 supported on the planetary carrier 16 via the second pinion gears 17 and 17 are different from each other in each power transmission unit U. The difference is 90°. For example, in Fig. 2, the eccentric disc 18 of the power transmission unit U at the left end is displaced upward in the figure relative to the input shaft 11, and the eccentric disc 18 of the third power transmission unit U from the left is displaced relative to the input shaft 11. The bottom shifts in the figure, and the eccentric disks 18, 18 of the second and fourth power transmission units U and U from the left are located in the middle of the up-down direction.

Although the shape of the connecting rod 19 is schematically shown in FIGS. 1 to 6 , the actual shape of the connecting rod 19 will be described based on FIG. 7 .

The large end portion 19a of the connecting rod 19 has an inner peripheral surface Pa with a radius Ra and an outer peripheral surface Pb with a radius Rb larger than Ra, and the center Obb of the outer peripheral surface Pb is smaller by a distance a from the center Oa of the inner peripheral surface Pa. The end portion 19b is offset sideways. Therefore, the radial wall thickness of the large end portion 19a is not uniform in the circumferential direction, the wall thickness becomes smaller on the side away from the small end portion 19b, and the wall thickness becomes larger on the side closer to the small end portion 19b.

In the center of the triangular-shaped connecting portion 19c, a triangular-shaped through hole 19d is formed. The through-hole 19d penetrates both axial surfaces of the connecting rod 19, and the inner edge portion Ea of the through-hole 19d facing the large end portion 19a is formed by the The outer peripheral surface Pb of the large end portion 19a is constituted by a circular arc having a radius Rc of the center Ob. The radius Rc of the inner edge portion Ea of the through hole 19d is set smaller than the radius Rb of the outer peripheral surface Pb of the large end portion 19a by a distance b.

The connection part 19c has two outer edge parts Eb, Eb, and these two outer edge parts Eb, Eb extend from the side of the small end part 19b toward the side of the big end part 19a while expanding each other, and the outer edge parts Eb, Eb and the big end part The outer peripheral surface Pb of 19a is connected tangentially.

Next, the action of the embodiment of the present invention having the above configuration will be described.

First, the function of one power transmission unit U of the continuously variable transmission T will be described. When the rotation shaft 14 a of the shift actuator 14 is relatively rotated with respect to the input shaft 11 , the carrier 16 rotates around the axis L1 of the input shaft 11 . At this time, the center O of the carrier 16 , that is, the center of the equilateral triangle formed by the first pinion 15 and the two second pinions 17 , 17 rotates around the axis L1 of the input shaft 11 .

3 and 5 show the state that the center O of the planetary carrier 16 is located on the opposite side to the output shaft 12 relative to the first pinion 15 (that is, the input shaft 11). The eccentric amount of 11 becomes the largest, and the gear ratio of the continuously variable transmission T becomes the highest state. Figures 4 and 6 show the state that the center O of the planet carrier 16 is located on the same side as the output shaft 12 relative to the first pinion 15 (that is, the input shaft 11). The eccentric amount of 11 becomes the minimum, and the transmission ratio of the continuously variable transmission T becomes the minimum state.

In the highest state shown in FIG. 5, if the input shaft 11 is rotated by the engine E and the rotary shaft 14a of the shift actuator 14 is rotated at the same speed as the input shaft 11, the input shaft 11, the rotary shaft 14a, the planetary The carrier 16 , the first pinion 15 , the two second pinions 17 , 17 , and the eccentric disk 18 eccentrically rotate counterclockwise around the input shaft 11 (see arrow A) in an integrated state. During rotation from FIG. 5(A) to FIG. 5(C) through FIG. 19 swings the swing link 13 pivotally supported by the small end portion 19 b of the link 19 via the pin 26 in the counterclockwise direction (see arrow B). FIG. 5(A) and FIG. 5(C) show both ends of the swing link 13 swinging in the arrow B direction.

In this way, when the swing link 13 swings in the direction of the arrow B, the roller 25 ... engages in the wedge-shaped space between the outer part 22 and the inner part 23 of the one-way clutch 21, thereby transmitting the rotation of the outer part 22 through the inner part 23 to the output shaft 12, and therefore, the output shaft 12 rotates counterclockwise (see arrow C).

When the input shaft 11 and the first pinion 15 further rotate, the ring gear 18 a and the eccentric disk 18 meshing with the first pinion 15 and the second pinion 17 , 17 rotate eccentrically counterclockwise (see arrow A). During rotation from FIG. 5(C) to FIG. 5(A) through FIG. 19 swings the swing link 13 pivotally supported by the small end portion 19 b of the link 19 via the pin 26 in the clockwise direction (see arrow B′). FIG. 5(C) and FIG. 5(A) show both ends of the swing link 13 swinging in the arrow B′ direction.

In this way, when the swing link 13 swings in the direction of the arrow B', the roller 25 ... is pushed out from the wedge-shaped space between the outer part 22 and the inner part 23 while compressing the engagement spring 24 ..., thereby making the outer part 22 relatively The inner part 23 slips so that the output shaft 12 does not rotate.

As above, when the swing link 13 swings back and forth, the output shaft 12 rotates counterclockwise (see arrow C) only when the swing direction of the swing link 13 is counterclockwise (see arrow B). Therefore, the output The shaft 12 rotates intermittently.

FIG. 6 is a diagram showing the action when the continuously variable transmission T is operated in the lowest state. At this time, since the position of the input shaft 11 coincides with the center of the eccentric disk 18 , the eccentric amount of the eccentric disk 18 relative to the input shaft 11 is zero. In this state, if the input shaft 11 is rotated by the engine E and the rotation shaft 14a of the shift actuator 14 is rotated at the same speed as the input shaft 11, the input shaft 11, the rotation shaft 14a, the planetary carrier 16, the first small The gear 15 , the two second pinion gears 17 , 17 , and the eccentric disk 18 eccentrically rotate counterclockwise around the input shaft 11 (see arrow A) in an integrated state. However, since the eccentricity of the eccentric disk 18 is zero, the reciprocating stroke of the connecting rod 19 is also zero, and the output shaft 12 does not rotate.

Therefore, if the shift actuator 14 is driven to set the position of the planet carrier 16 between the highest state of FIG. 3 and the lowest state of FIG. run.

In the continuously variable transmission T, the phases of the eccentric discs 18 of the four power transmission units U... that are arranged in parallel are staggered by 90° from each other. Therefore, the four power transmission units U... alternately transmit driving force, that is, four one-way clutches Any one of 21... must be in an engaged state, whereby the output shaft 12 can be continuously rotated.

However, when the outer peripheral surface of the ball bearing 20 is pressed into the inner peripheral surface Pa of the large end portion 19a of the connecting rod 19, the ball bearing 20 receives a radially inward pressing reaction force from the inner peripheral surface Pa of the large end portion 19a. And deformation. At this time, if the press-fitting reaction force directed inward in the radial direction is uniform in the circumferential direction, the roundness of the press-fitted ball bearing 20 can be ensured. In the vicinity of the portion where the large end portion 19a and the connecting portion 19c are connected, the rigidity is locally increased, and therefore, there is a problem that the ball bearing 20 is deformed by a press-fitting load, resulting in a decrease in roundness.

Comparative Example 1 in FIG. 8 is a comparative example in which the center Oa of the inner peripheral surface Pa coincides with the center Obb of the outer peripheral surface Pb, and the radius Rb of the outer peripheral surface Pb is the same as the radius Rc of the inner edge part Ea. The wall of the large end part 19a Thickness is set small in order to achieve miniaturization and weight reduction, and its weight is 422g.

In Comparative Example 1, the wall thickness of the large end portion 19a is thin, and the rigidity of the portion connecting the large end portion 19a and the connecting portion 19c is locally increased, so the press-fit reaction force of this portion is locally increased, causing the ball bearing 20 The deformation was radially inward, thereby deteriorating the roundness to 52.5 μm. The roundness refers to the difference between the maximum radius and the minimum radius of the rolling tracks of the balls of the ball bearing 20. In the case of a perfect circle, the roundness is 0 μm, and the larger the value, the worse the roundness.

Comparative example 2 is a comparative example in which the wall thickness of the large end portion 19 a of comparative example 1 is increased, and the others are the same as comparative example 1. In Comparative Example 2, by increasing the thickness of the large end portion 19a, the weight increased to 918g, and the radius R2 of the outer peripheral surface Pb of the large end portion 19a was also increased. However, since the increase in wall thickness increases the rigidity of the large end portion 19a as a whole, the sudden change in rigidity at the portion where the large end portion 19a and the connecting portion 19c are connected is alleviated, so the roundness is greatly reduced to 12.5. μm.

Comparative Example 3 is a comparative example in which the center Obb of the outer peripheral surface Pb is shifted toward the small end portion 19b side with respect to the center Oa of the inner peripheral surface Pa of the large end portion 19a of Comparative Example 2, and the weight is the same as that of Comparative Example 1 and Comparative Example 2. The middle 640g. The sharp change in rigidity was further alleviated by increasing the wall thickness at the portion where the large end portion 19a and the connection portion 19c were connected, and thus the roundness was further reduced to 9.5 μm. However, in Comparative Example 3, at the portion where the large end portion 19a and the connection portion 19c are connected, the imbalance in rigidity still remains, and thus the roundness is impaired.

In the embodiment, the radius Rc of the inner edge portion Ea of the through hole 19d in Comparative Example 3 is set smaller than the radius Rb of the outer peripheral surface Pb, so that the rigidity of the portion where the large end portion 19a faces the inner edge portion Ea is locally reduced. . As a result, the weight of the connecting rod 19 of the embodiment was suppressed to 625 g, and the roundness was improved to 3.8 better than any of Comparative Examples 1 to 3.

FIG. 9 is a diagram for explaining the effect of the through hole 19d. In Comparative Example 4 shown in FIG. 19e plugged. It can be seen that the rigidity of the large end portion 19a facing the inner edge portion Ea of the through hole 19d is significantly improved by the web 19e, and the roundness is greatly deteriorated. On the other hand, in the embodiment shown in FIG. 9(A) , by forming the through hole 19d, the rigidity of the large end portion 19a facing the inner edge portion Ea of the through hole 19d is reduced, and the roundness is greatly improved.

FIG. 10 is a diagram for explaining the effect of the outer edge portions Eb, Eb of the connecting portion 19c. In Comparative Example 5 shown in FIG. The outer peripheral surface Pb of the portion 19a is connected tangentially, but connected crosswise. As a result, there is a problem that the wall thickness of the large end portion 19a changes sharply in the vicinity of the intersection, and the roundness is deteriorated due to the sharp change in rigidity caused thereby. On the other hand, in the embodiment shown in FIG. 10(A), the outer edge portions Eb, Eb of the connecting portion 19c are connected tangentially to the outer peripheral surface Pb of the large end portion 19a. Therefore, the large end portion 19a is prevented from The wall thickness changes sharply near the intersection, which improves roundness.

As described above, according to the present embodiment, the rigidity of the large end portion 19a can be made uniform in the circumferential direction while suppressing the weight increase of the connecting rod 19 to a minimum, and the rigidity of the ball bearing 20 press-fitted into the large end portion 19a can be ensured. roundness and achieve a reduction in friction and an increase in durability.

As mentioned above, although embodiment of this invention was described, this invention can make various design changes in the range which does not deviate from the summary.

For example, the bearing of the present invention is not limited to the ball bearing 20 of the embodiment, and may be any bearing such as a needle bearing, a roller bearing, or a sliding bearing.

In addition, the driving source of the present invention is not limited to the engine E of the embodiment, and may be any driving source such as a motor generator.

Claims (3)

1. A power transmission device for a vehicle, comprising: an input shaft (11), which is connected to a driving source (E); an output shaft (12) arranged parallel to said input shaft (11); a swing chain link (13), which is supported on the output shaft (12) in a swingable manner; A one-way clutch (21), which is arranged between the output shaft (12) and the swing link (13), and when the swing link (13) swings in one direction, the one-way clutch (21) is engaged, and the one-way clutch (21) is disengaged when the swing link (13) swings in the other direction; an eccentric disc (18) which rotates eccentrically integrally with said input shaft (11); a variable speed actuator (14) that varies the eccentricity of said eccentric disc (18); and a connecting rod (19), which connects the eccentric disc (18) and the swing link (13), The vehicle power transmission device is characterized in that, The connecting rod (19) includes: an annular large end portion (19a), which is pressed into a bearing (20) provided on the outer peripheral surface of the eccentric disk (18); a small end portion (19b), which is connected to said swing link (13); and a connecting portion (19c) which connects said large end portion (19a) and said small end portion (19b), A through hole (19d) penetrating both surfaces in the axial direction is formed in the connecting portion (19c), and the center (Ob) of the outer peripheral surface (Pb) of the large end portion (19a) is opposite to the inner peripheral surface (Pa) The center (Oa) of the through hole (19d) is eccentric to the side of the small end (19b), and the inner edge (Ea) of the through hole (19d) facing the large end (19a) is connected to the outer peripheral surface (Pb ) together have a center (Ob) of the arc. 2. The vehicle power transmission device according to claim 1, wherein: The radius (Rc) of the inner edge portion (Ea) of the through hole (19d) is smaller than the radius (Rb) of the outer peripheral surface (Pb) of the large end portion (19a). 3. The vehicle power transmission device according to claim 1 or claim 2, wherein: The outer edge (Eb) of the through hole (19d) is connected tangentially to the outer peripheral surface (Pb) of the large end (19a).