JP7120102B2 - vehicle drive shaft - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle drive shaft, and more particularly to a fitting structure between a vehicle drive shaft and a joint.

A vehicle drive shaft is known that includes a power transmission shaft and a joint portion fitted to one end of the power transmission shaft. For example, it is a vehicle drive shaft described in Patent Document 1. In the vehicle drive shaft disclosed in Patent Document 1, the power transmission shaft and the joint are spline-fitted. In the vehicle drive shaft disclosed in Patent Document 1, the spline teeth formed on the power transmission shaft are inclined with respect to the rotation axis to form a predetermined twist angle. This suppresses backlash in the circumferential direction in spline fitting between the power transmission shaft and the joint.

JP-A-2005-214399

By the way, in the vehicle drive shaft described in Patent Document 1, the torsional rigidity of the vehicle drive shaft affects the vehicle performance. For example, the generation of muffled noise is improved by reducing the torsional rigidity of the vehicle drive shaft, and the stability of driving operation is improved by increasing the torsional rigidity of the vehicle drive shaft. The torsional rigidity of a vehicle drive shaft is determined, for example, by the length dimension and diameter dimension of the power transmission shaft in the vehicle drive shaft. However, since the length of the power transmission shaft is determined by the positional relationship related to the frame of the vehicle, such as the positional relationship between the differential mechanism and the drive wheels, it is difficult to change easily. In addition, the diameter dimension of the power transmission shaft has a lower limit for ensuring the strength of the vehicle drive shaft, so the range in which it can be changed is narrow, so the range in which the torsional rigidity of the vehicle drive shaft can be adjusted is narrow. . Therefore, in the vehicle drive shaft described in Patent Document 1, it is difficult to adjust the torsional rigidity of the vehicle drive shaft.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle drive shaft whose torsional rigidity can be adjusted by means of a fitting structure.

The gist of the present invention is a power transmission shaft, a first joint fitted to one end of the power transmission shaft, a hub bearing fitted to the other end of the power transmission shaft, and a hub bearing. a second joint to which is fitted, the first fitting portion being a fitting portion between the power transmission shaft and the first joint; the power transmission shaft and the second One spline tooth and the other spline tooth of a second fitting portion that is a fitting portion with a joint and a third fitting portion that is a fitting portion between the second joint and the hub bearing are contact points. Either one of the one spline tooth and the other spline tooth forms a torsion angle forming a predetermined angle with respect to the rotation axis so that the torsional rigidity is set. It is in.

According to the vehicle drive shaft of the present invention, the first fitting portion that is the fitting portion between the power transmission shaft and the first joint, and the second fitting portion that is the fitting portion between the power transmission shaft and the second joint are provided. At least one of the second fitting portion and the third fitting portion, which is the fitting portion between the second joint and the hub bearing, is spline-fitted. In the drive shaft for a vehicle of the present invention, in the at least one spline-fitted fitting portion, one spline tooth and the other spline tooth of the mutually fitted spline teeth come into contact at a point of contact. The torsional rigidity is set by forming a predetermined torsion angle with respect to the rotation axis so that one of the one spline tooth and the other spline tooth is in contact with the other spline tooth . As a result, the length of the shaft for transmitting the driving force can be changed according to the direction of the torsion angle. The torsional rigidity of the drive shaft can be adjusted.

1 is a cross-sectional view showing a part of a main part of a vehicle drive shaft to which the present invention is applied; FIG. FIG. 2 is an enlarged view showing an enlarged main part of a first fitting portion to be spline-fitted in the vehicle drive shaft of FIG. 1 ; FIG. 2 is an enlarged view showing an enlarged main part of a second fitting portion to be spline-fitted in the vehicle drive shaft of FIG. 1 ; 2 is an enlarged view showing an enlarged main part of a third fitting portion spline-fitted in the vehicle drive shaft of FIG. 1; FIG. FIG. 3 is a view corresponding to FIG. 2 and an enlarged view showing an enlarged main part of the first fitting portion to be spline-fitted when the direction of the torsion angle is changed; FIG. 4 is a view corresponding to FIG. 3 and an enlarged view showing an enlarged main part of the second fitting portion to be spline-fitted when the direction of the torsion angle is changed; FIG. 5 is a view corresponding to FIG. 4 and an enlarged view showing an enlarged main part of the third fitting portion to be spline-fitted when the direction of the torsion angle is changed; FIG. 2 is a schematic diagram showing the positional relationship of spline-fitted fitting portions in the vehicle drive shaft of FIG. 1 ; FIG. 9 is a schematic diagram showing the positional relationship of spline-fitted fitting portions in the vehicle drive shaft of FIG. 1 , showing a different aspect from FIG. 8 ;

The present invention is applied to the drive shaft of an engine-driven vehicle having an engine as a driving force source for running, a hybrid vehicle having a rotating machine for running, that is, a driving electric motor in addition to the engine as a driving force source for running, and an electric vehicle. Applies. Moreover, the present invention can also be applied to an electric vehicle or the like having only an electric motor as a driving force source.

An embodiment of the present invention will be described in detail below with reference to the drawings. In the following examples, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, etc. of each part are not necessarily drawn accurately.

FIG. 1 is a cross-sectional view showing a part of a vehicle drive shaft 10 to which the present invention is applied. The vehicle drive shaft 10 is a pair of left and right power transmission members respectively provided between a differential mechanism 12 and a pair of left and right drive wheels 14 indicated by a dashed line in FIG. Arrow A in FIG. 1 indicates the direction of transmission of driving force. A vehicle drive shaft 10 shown in FIG. 1 is provided on the left side of the vehicle with respect to the forward direction of the vehicle, out of a pair of left and right vehicle drive shafts. The pair of left and right vehicle drive shafts are formed, for example, with the same length dimension or different length dimensions. An arrow B in FIG. 1 indicates the rotation direction of the vehicle drive shaft 10 and indicates the forward direction of the vehicle including the vehicle drive shaft 10 .

As shown in FIG. 1, the vehicle drive shaft 10 includes a power transmission shaft 20 that transmits driving force, and a first joint 22 that is an inboard joint provided on one end of the power transmission shaft 20, that is, on the differential mechanism 12 side. and a second joint 24 which is an outboard joint provided on the other end side of the power transmission shaft 20, that is, on the drive wheel 14 side. The first joint 22 is a constant velocity universal joint, and is provided between the power transmission shaft 20 and a first shaft portion 30 connected to an output member (not shown) of the differential mechanism 12 . and the power transmission shaft 20 at a constant speed regardless of the intersection angle between the rotation axis C1 of the first shaft portion 30 and the rotation axis C of the power transmission shaft 20 . For the first joint 22, for example, a tripod-type sliding constant velocity universal joint is used. The second joint 24 is a constant velocity universal joint, and is provided between the second shaft portion 32 connected to the drive wheel 14 and the power transmission shaft 20 to connect the second shaft portion 32 and the power transmission shaft 20 together. The rotation is transmitted at a constant speed regardless of the intersection angle between the rotation axis C2 of the second shaft portion 32 and the rotation axis C of the power transmission shaft 20 therebetween. For the second joint 24, for example, a Rzeppa-type fixed constant velocity universal joint or the like is used. FIG. 1 shows a state in which the first shaft portion 30, the power transmission shaft 20, and the second shaft portion 32 are concentric.

The first joint 22 includes an inner ring 22a fitted to one end 20a of the power transmission shaft 20 on the side of the differential mechanism 12, i.e., the inner side of the vehicle body, and an outer ring 22c having a storage chamber 22b formed therein. The inner ring 22a is housed in a housing chamber 22b formed in the outer ring 22c. The outer ring 22c includes a first shaft portion 30 arranged to protrude in the direction of the rotation axis C1 of the outer ring 22c.

The inner ring 22a is formed with projections 22d protruding outward in the circumferential direction at equal intervals on the outer circumference. The protrusion 22d is formed to support the roller 22e. In this embodiment, three rollers 22e are provided. The inner peripheral surface of the outer ring 22c is provided with guide grooves 22f for receiving the rollers 22e and guiding the rollers 22e in a direction parallel to the rotation axis C1. As a result, the inner ring 22a is fitted to the outer ring 22c so as to be movable relative to the outer ring 22c in the direction of the rotation axis C1, but not to be relatively rotatable. The outer ring 22c is allowed to move in an arc starting from the one end 20a of the power transmission shaft 20 within a predetermined range. Spline teeth 62, which will be described later, are formed on the inner peripheral surface of the inner ring 22a. 60a are spline-fitted.

An opening between the power transmission shaft 20 and the outer ring 22c is covered with a bellows-shaped boot 36 made of a soft resin material. The boot 36 has a large diameter end fitted around the outer ring 22 c and a small diameter end fitted to the power transmission shaft 20 . The boot 36 is filled with lubricating grease.

The second joint 24 includes an inner ring 24a fitted to the drive wheel 14 side of the power transmission shaft 20, that is, the other end portion 20b on the outside of the vehicle body, and an outer ring 24c having a storage chamber 24b formed therein. The inner ring 24a is housed in a housing chamber 24b formed in the outer ring 24c. The outer ring 24c includes a second shaft portion 32 arranged to protrude in the direction of the rotation axis C2 of the outer ring 24c. Spline teeth 68, which will be described later, are formed on the outer peripheral surface of the second shaft portion 32. As shown in FIG.

A substantially cylindrical cage 24e and a plurality of balls 24f are provided between the inner ring 24a and the outer ring 24c. These balls 24f are held within a plurality of holding holes formed in the cage 24e. A plurality of guide grooves 24g corresponding to a plurality of balls 24f are formed in the outer peripheral surface of the inner ring 24a and the outer peripheral surface of the outer ring 24c in the direction of the rotation axis C2. The plurality of balls 24f are fitted and guided in the guide grooves 24g. As a result, the outer ring 24c and the second shaft portion 32 are allowed to move in an arc within a predetermined range starting from the other end portion 20b of the power transmission shaft 20 outside the vehicle body. Spline teeth 66, which will be described later, are formed on the inner peripheral surface of the inner ring 24a. The surface 64a is spline-fitted.

An opening between the power transmission shaft 20 and the outer ring 24c is covered with a bellows-shaped boot 38 made of a soft resin material. The boot 38 has a large diameter end fitted around the outer ring 24 c and a small diameter end fitted to the power transmission shaft 20 . The boot 38 is filled with lubricating grease.

A hub bearing 40 connected to the drive wheel 14 is fitted to the second shaft portion 32 . The second shaft portion 32 is fitted in a fitting hole 40a formed in the hub bearing 40 so as not to rotate relative to each other. A spline tooth 70, which will be described later, is formed in the fitting hole 40a, and a spline tooth surface 70a of the spline tooth 70 and a spline tooth surface 68a of the spline tooth 68 formed on the second shaft portion 32 are spline-fitted. ing.

Driving force is transmitted to the vehicle drive shaft 10 in the direction indicated by the arrow A in FIG. Driving force is transmitted from the differential mechanism 12 to the power transmission shaft 20 via the first joint 22 . The driving force transmitted to the power transmission shaft 20 is transmitted to the hub bearing 40 via the second joint 24 and the second shaft portion 32 provided in the second joint 24, and then transmitted from the hub bearing 40 to the drive wheel 14. It is

2, 3, and 4 are enlarged views showing the main parts of the spline-fitted fitting portion of the vehicle drive shaft 10. FIG. Specifically, FIG. 2 is an enlarged view of a first fitting portion 50 that is a fitting portion between the power transmission shaft 20 and the first joint 22, and is formed at one end portion 20a of the power transmission shaft 20. 2 shows a fitted state of the spline teeth 60 formed on the inner ring 22 a of the first joint 22 and the spline teeth 62 formed on the inner ring 22 a of the first joint 22 . FIG. 3 is an enlarged view of the second fitting portion 52, which is the fitting portion between the power transmission shaft 20 and the second joint 24. The spline teeth formed on the other end portion 20b of the power transmission shaft 20 are shown in FIG. 64 and spline teeth 66 formed on the inner ring 24 of the second joint 24 are shown. 4 is an enlarged view of a third fitting portion 54, which is a fitting portion between the second shaft portion 32 provided in the second joint 24 and the hub bearing 40, and is formed in the second shaft portion 32. FIG. 2 shows a state in which the spline teeth 68 formed on the hub bearing 40 and the spline teeth 70 formed in the fitting hole 40a of the hub bearing 40 are fitted.

As shown in FIG. 2 , in the first fitting portion 50 , the spline teeth 60 formed on the one end portion 20 a of the power transmission shaft 20 are aligned with the rotation axis of the first fitting portion 50 , that is, the rotation axis of the power transmission shaft 20 . A twist angle θ1 forming a predetermined angle with respect to the center C is formed. The predetermined angle is an acute angle formed with respect to the rotation axis C with the clockwise direction being positive. That is, the one end portion 20a of the power transmission shaft 20 has spline teeth 60 formed on the outer peripheral surface thereof at a right-handed twist angle .theta. The spline teeth 62 formed on the inner peripheral surface of the inner ring 22a of the first joint 22 are formed parallel to the rotation axis C. As shown in FIG.

In the case of forward running of the vehicle, which poses a problem in terms of vehicle performance, the relationship between the first joint 22 and the power transmission shaft 20 is such that the first joint 22 becomes the driving side for transmitting the driving force, and the power transmission shaft 20 transmits the driving force. It becomes the driven side to which the power is transmitted. That is, in the first fitting portion 50, the spline tooth 62 rotates in the direction indicated by arrow D in FIG. is brought into contact with Therefore, as shown in FIG. 2, in the first fitting portion 50, the spline tooth surface 60a of the spline tooth 60 and the spline tooth surface 62a of the spline tooth 62 are located on the right side of FIG. are brought into contact with each other at the contact point S1.

As shown in FIG. 3 , in the second fitting portion 52 , the spline teeth 64 formed on the other end portion 20 b of the power transmission shaft 20 are aligned with the rotational axis of the second fitting portion 52 , i.e., the rotation of the power transmission shaft 20 . A twist angle θ2 forming a predetermined angle with respect to the axis C is formed. The predetermined angle is an acute angle formed with respect to the rotation axis C with the clockwise direction being positive. That is, the other end portion 20b of the power transmission shaft 20 has spline teeth 64 formed on its outer peripheral surface at a right-handed twist angle .theta. The spline teeth 66 formed on the inner peripheral surface of the inner ring 24a of the second joint 24 are formed parallel to the rotation axis C. As shown in FIG.

In the case of forward running of the vehicle, the relationship between the second joint 24 and the power transmission shaft 20 is such that the power transmission shaft 20 is the driving side that transmits the driving force, and the second joint 24 is the driven side that transmits the driving force. Become. That is, in the second fitting portion 52, the spline tooth flank 64a of the spline tooth 64 on the driving side rotates in the direction indicated by arrow D in FIG. 66a. Therefore, as shown in FIG. 3, in the second fitting portion 52, the spline tooth flank 64a of the spline tooth 64 and the spline tooth flank 66a of the spline tooth 66 are located on the drive wheel 14 side on the left side of FIG. They are brought into contact at the contact point S2.

As shown in FIG. 4, in the third fitting portion 54, the spline teeth 68 formed on the second shaft portion 32 provided in the second joint 24 are aligned with the rotation axis of the second fitting portion 53, that is, the second joint. A twist angle θ3 forming a predetermined angle with respect to the rotation axis C2 of 24 is formed. The predetermined angle is an acute angle formed with respect to the rotation axis C2 with the clockwise direction being positive. That is, the second shaft portion 32 has spline teeth 68 formed on the outer peripheral surface thereof at a right-handed twist angle θ3 toward the drive wheel 14 . The spline teeth 70 formed on the inner peripheral surface of the fitting hole 40 a of the hub bearing 40 are formed parallel to the rotation axis C 2 of the second joint 24 .

In the case of forward running of the vehicle, the relationship between the second joint 24 and the hub bearing 40 is such that the second joint 24 is the driving side that transmits the driving force, and the hub bearing 40 is the driven side that transmits the driving force. 4, the spline tooth flanks 68a of the spline teeth 68 on the driving side rotate to the spline tooth flanks of the spline teeth 70 on the driven side. 70a. Therefore, as shown in FIG. 4, in the third fitting portion 54, the spline tooth surface 68a of the spline tooth 68 and the spline tooth surface 70a of the spline tooth 70 are located on the drive wheel 14 side on the left side of FIG. are brought into contact with each other at a contact point S3.

5, 6, and 7 are enlarged views showing the essential parts of the spline-fitted fitting portion when the direction of the torsion angle is changed in the vehicle drive shaft 10. FIG. FIG. 5 is a view corresponding to FIG. 2, and is an enlarged view of a first fitting portion 50 that is a fitting portion between the power transmission shaft 20 and the first joint 22. As shown in FIG. FIG. 6 is a view corresponding to FIG. 3, and is an enlarged view of the second fitting portion 52 that is the fitting portion between the power transmission shaft 20 and the second joint 24. As shown in FIG. FIG. 7 is a view corresponding to FIG. 4, and is an enlarged view of a third fitting portion 54 that is a fitting portion between the second shaft portion 32 provided in the second joint 24 and the hub bearing 40. FIG. .

As shown in FIG. 5 , in the first fitting portion 50 , the spline teeth 60 formed on the one end portion 20 a of the power transmission shaft 20 are twisted at a predetermined angle with respect to the rotation axis C of the power transmission shaft 20 . It forms an angle θ4. The predetermined angle is an acute angle formed with respect to the rotation axis C with the counterclockwise direction being positive. That is, the one end portion 20a of the power transmission shaft 20 has spline teeth 60 formed on the outer peripheral surface thereof with a left-hand twist angle θ4, which is a left-hand twist angle. The spline teeth 62 formed on the inner peripheral surface of the inner ring 22a of the first joint 22 are formed parallel to the rotation axis C1 of the first joint.

When the vehicle is traveling forward, the spline teeth 62 rotate in the direction indicated by arrow D in FIG. be touched. Therefore, as shown in FIG. 5, in the first fitting portion 50, the spline tooth flank 60a of the spline tooth 60 and the spline tooth flank 62a of the spline tooth 62 are located on the left side of FIG. They are brought into contact at the contact point S4.

As shown in FIG. 6, in the second fitting portion 52, the spline teeth 64 formed on the other end portion 20b of the power transmission shaft 20 form a predetermined angle with respect to the rotation axis C of the power transmission shaft 20. A torsion angle θ5 is formed. The predetermined angle is an acute angle formed with respect to the rotation axis C with the counterclockwise direction being positive. That is, the other end portion 20b of the power transmission shaft 20 has spline teeth 64 formed on the outer peripheral surface thereof with a left-hand twist angle θ5, which is a counter-clockwise twist angle. The spline teeth 66 formed on the inner peripheral surface of the inner ring 24a of the second joint 24 are formed parallel to the rotation axis C. As shown in FIG.

When the vehicle is traveling forward, the spline tooth 64 rotates in the direction indicated by arrow D in FIG. be abutted. Therefore, as shown in FIG. 6, in the second fitting portion 52, the spline tooth flank 64a of the spline tooth 64 and the spline tooth flank 66a of the spline tooth 66 are located on the right side of FIG. are brought into contact with each other at the contact point S5.

As shown in FIG. 7, in the third fitting portion 54, the spline teeth 68 formed on the second shaft portion 32 provided in the second joint 24 are aligned with the rotational axis of the third fitting portion 54, that is, the second joint. A twist angle θ6 forming a predetermined angle with respect to the rotation axis C2 of 24 is formed. The predetermined angle is an acute angle formed with the counterclockwise direction positive with respect to the rotation axis C2. That is, the second shaft portion 32 has spline teeth 68 formed on the outer peripheral surface thereof with a left-hand twist angle θ6, which is a left-hand twist angle. The spline teeth 70 formed on the inner peripheral surface of the fitting hole 40a of the hub bearing 40 are formed parallel to the rotation axis C2.

When the vehicle is traveling forward, the spline tooth 68 rotates in the direction indicated by arrow D in FIG. be abutted. Therefore, as shown in FIG. 7, in the second fitting portion 52, the spline tooth flank 68a of the spline tooth 68 and the spline tooth flank 70a of the spline tooth 70 are located on the right side of FIG. are brought into contact with each other at a contact point S6.

8 and 9 are schematic diagrams showing the positional relationship of spline-fitted fitting portions in the vehicle drive shaft 10. FIG. FIG. 8 shows that in the first fitting portion 50, the second fitting portion 52 and the third fitting portion 54, one spline teeth 60, 64 and 68 of the mutually fitted spline teeth are clockwise. The positional relationship is shown when right twist angles θ1, θ2, and θ3 are formed.

An axial length L1 shown in FIG. 8 indicates an axial length dimension between the first fitting portion 50 and the second fitting portion 52 in the vehicle drive shaft 10 . The axial length dimension is the axial length dimension for transmitting the driving force, ie, the torque, in the vehicle drive shaft 10 . Specifically, the axial length L1 is the distance between a contact point S1 at which the spline tooth flank 62a and the spline tooth flank 60a abut and a contact point S2 at which the spline tooth flank 64a and the spline tooth flank 66a abut. It shows the distance in the direction of the rotation axis C between.

An axial length L2 shown in FIG. 8 indicates, for example, the axial length dimension between the inner side of the vehicle body of the second shaft portion 32, that is, the end portion of the second shaft portion 32 on the side of the differential mechanism 12 and the third fitting portion 54. ing. The axial length dimension is the axial length dimension for transmitting the driving force, ie, the torque, in the vehicle drive shaft 10 . Specifically, the axial length L2 is the rotation axis between the end of the second shaft portion 32 on the side of the differential mechanism 12 and the contact point S3 where the spline tooth surface 68a and the spline tooth surface 70a are brought into contact. The distance in the center C2 direction is shown.

FIG. 9 shows that in the first fitting portion 50, the second fitting portion 52 and the third fitting portion 54, one spline teeth 60, 64 and 68 of the mutually fitted spline teeth are left-handed. The positional relationship is shown when left twist angles θ4, θ5, and θ6 are formed.

An axial length L3 shown in FIG. 9 indicates the axial length dimension between the first fitting portion 50 and the second fitting portion 52 in the vehicle drive shaft 10 . Specifically, the axial length L3 is the distance between a contact point S4 at which the spline tooth flank 62a and the spline tooth flank 60a abut and a contact point S5 at which the spline tooth flank 64a and the spline tooth flank 66a abut. It shows the distance in the direction of the rotation axis C between.

An axial length L4 shown in FIG. 9 indicates, for example, the axial length dimension between the inner side of the vehicle body of the second shaft portion 32, that is, the end portion of the second shaft portion 32 on the side of the differential mechanism 12 and the third fitting portion 54. ing. Specifically, the axial length L4 is the rotation axis between the end of the second shaft portion 32 on the side of the differential mechanism 12 and the contact point S6 where the spline tooth surface 68a and the spline tooth surface 70a are brought into contact. The distance in the center C2 direction is shown.

As shown in FIGS. 8 and 9, if the spline teeth 60, 64, 68 form clockwise right-hand helix angles θ1, θ2, θ3, respectively, then the spline teeth 60, 64, 68 are left-handed. The axial length dimension of the vehicle drive shaft 10 is larger than when the left-hand twist angles θ4, θ5, and θ6 are formed. Specifically, in the axial length dimension between the first fitting portion 50 and the second fitting portion 52, the axial length L1 when the right twist angles are θ1, θ2, and θ3 corresponds to the left twist angles θ4 and θ5. , .theta.6. Further, regarding the axial length dimension between the end of the second shaft portion 32 on the side of the differential mechanism 12 and the third fitting portion 54, the axial length L2 when the right torsion angles are θ1, θ2, and θ3 is left. It is longer than the axial length L4 when the twist angles are θ4, θ5, and θ6.

The vehicle drive shaft 10 can reduce the torsional rigidity of the vehicle drive shaft 10 by increasing the length of the torque-transmitting shaft. , 64 and 68 are formed with right helix angles θ1, θ2 and θ3 respectively, the vehicle drive shaft 10 is more stable than the case where the spline teeth 60, 64 and 68 are formed with left helix angles θ4, θ5 and θ6 respectively. can realize low rigidity. Further, by forming left-handed twist angles θ4, θ5, and θ6 in spline teeth 60, 64, and 68, respectively, compared to the case where right-handed twist angles θ1, θ2, and θ3 are formed in spline teeth 60, 64, and 68, respectively, High rigidity of the vehicle drive shaft 10 can be realized.

In this embodiment, as shown in FIGS. 2 to 7, the first fitting portion 50, the second fitting portion 52, and the third fitting portion 54 are spline-fitted, and the spline teeth that fit with each other are formed. By forming a predetermined twist angle in one of the spline teeth 60, 64, 68, the torsional rigidity adjusted to realize the vehicle drive shaft 10 with reduced rigidity or increased rigidity is set. be. However, even if the first fitting portion 50 out of the first fitting portion 50, the second fitting portion 52, and the third fitting portion 54 is spline-fitted, the vehicle drive shaft 10 may torsional stiffness can be set. For example, in the first fitting portion 50, by forming the spline tooth 60 with the right helix angle θ1, the contact point S1 between the spline tooth surface 60a and the spline tooth surface 62a can be formed outside the vehicle body, that is, on the drive wheel 14 side. Therefore, the length dimension of the torque-transmitting shaft of the vehicle drive shaft 10 can be increased. In the first fitting portion 50, the spline tooth 60 is formed with a left helix angle .theta.4, so that the contact point S4 between the spline tooth flank 60a and the spline tooth flank 62a is formed inside the vehicle body, that is, on the side of the differential mechanism 12. Therefore, the length dimension of the torque-transmitting shaft of the vehicle drive shaft 10 can be reduced. As a result, the torsional rigidity of the vehicle drive shaft 10 with reduced or increased rigidity is set.

Similarly, for example, when the second fitting portion 52 of the first fitting portion 50, the second fitting portion 52 and the third fitting portion 54 is spline-fitted, or the first fitting portion 50, Even when the third fitting portion 54 out of the second fitting portion 52 and the third fitting portion 54 is spline-fitted, the torsional rigidity of the vehicle drive shaft 10 can be set.

Of the pair of left and right vehicle drive shafts, a vehicle drive shaft (not shown) provided on the right side of the vehicle with respect to the forward direction of the vehicle has spline teeth 60, 64, and 68 with right twist angles θ1, θ2, and θ3, respectively. When formed, the shaft length dimension for torque transmission is smaller than when spline teeth 60, 64 and 68 are formed with left-hand helix angles .theta.4, .theta.5 and .theta.6, respectively. Therefore, the torsional rigidity of the vehicle drive shaft (not shown) is increased, resulting in high rigidity. Further, in the vehicle drive shaft (not shown), when the spline teeth 60, 64, 68 are formed with left-hand twist angles θ4, θ5, θ6, respectively, the spline teeth 60, 64, 68 are formed with right-hand twist angles θ1, θ2, Compared to the case where each θ3 is formed, the length dimension of the shaft for transmitting torque is increased, and the torsional rigidity is decreased.

In the case where the vehicle drive shaft 10 shown in this embodiment and the vehicle drive shaft (not shown) provided on the right side of the vehicle with respect to the forward direction of the vehicle have different lengths, for example, the vehicle drive shaft 10 may be installed in the vehicle (not shown). When the total length dimension is larger than that of the drive shaft for the vehicle and the shaft length for transmitting the driving force is long, the drive shaft 10 for the vehicle, which is the long axis, has a torsion of the fitting portion to which the spline is fitted. By changing the direction of the angle, it is possible to match the rigidity value of the vehicle drive shaft (not shown), which is the short axis.

As described above, according to the vehicle drive shaft 10 of the present embodiment, in the spline-fitted first fitting portion 50, the spline tooth 60 of the mutually fitted spline teeth 60, 62 is located at the rotation axis. The torsional rigidity is set by forming a right torsion angle θ1 or a left torsion angle θ4 forming a predetermined angle with respect to C. In the spline-fitted second fitting portion 52, the spline tooth 64 of the spline teeth 64 and 66 that are fitted to each other forms a predetermined angle with respect to the rotation axis C, which is a right twist angle θ2 or a left twist angle. The torsional rigidity is set by forming the torsion angle θ5. Furthermore, in the spline-fitted third fitting portion 54, the spline tooth 68 of the spline teeth 68 and 70 that are fitted to each other forms a predetermined angle with respect to the rotation axis C2, which is a right twist angle θ3 or a left twist angle θ3. The torsional rigidity is set by forming the torsion angle θ6. As a result, the length of the shaft for transmitting the driving force can be changed according to the direction of the torsion angle. The torsional rigidity of a pair of vehicle drive shafts 10 connected to both sides of the mechanism 12 can be adjusted to each other.

Although the preferred embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is not limited to these, and may be implemented in other aspects as well.

For example, in the above-described embodiment, in the vehicle drive shaft 10, the first fitting portion 50, the second fitting portion 52, and the third fitting portion 54 are spline-fitted to each other. Either one of the mating spline teeth forms the helix angle, but this is not necessarily the case. That is, the connecting portion between the first shaft portion 30 and the output member (not shown) of the differential mechanism 12 is spline-fitted, and one of the mutually-fitting spline teeth is twisted. It may form an angle. Further, for example, when the power transmission shaft 20 is formed by connecting two or more shafts, the connecting portions of the plurality of shafts are spline-fitted, and the spline teeth that are fitted to each other are used. Either one of the spline teeth may form a helix angle.

In the above-described embodiment, in the first fitting portion 50, the spline teeth 60 formed on the one end portion 20a of the power transmission shaft 20 form the right twist angle θ1 or the left twist angle θ4. Not limited to this, in the first fitting portion 50, for example, the spline teeth 62 formed on the inner ring 22a of the first joint 22 form a right helix angle θ1 or a left helix angle θ4, and the spline teeth 60 form the rotation axis C may be formed in parallel with Similarly, in the second fitting portion 52, the spline teeth 66 may form the right helix angle .theta.2 or the left helix angle .theta.5, and the spline teeth 64 may be formed parallel to the rotation axis C. Furthermore, in the third fitting portion 54, the spline teeth 70 may form the right helix angle .theta.3 or the left helix angle .theta.6, and the spline teeth 68 may be formed parallel to the rotation axis C2.

The right twist angles θ1, θ2, θ3 or the left twist angles θ4, θ5, θ6 may be the same angle or different angles. That is, in order to adjust the torsional rigidity of the vehicle drive shaft 10, they can be changed as appropriate.

The embodiments of the present invention have been described in detail above with reference to the drawings. Various modifications and improvements can be made based on knowledge.

10: Vehicle Drive Shaft 20: Power Transmission Shaft 20a: One End 20b: Other End 22: First Joint 24: Second Joint 40: Hub Bearing 50: First Fitting Portion 52: Second Fitting Portion 54: Third fitting portions 60, 62, 64, 66, 68, 70: spline teeth θ1, θ2, θ3: right twist angle (twist angle)
θ4, θ5, θ6: left twist angle (torsion angle)
C: Rotational axis C2: Rotational axis

Claims (1)

a power transmission shaft; a first joint fitted to one end of the power transmission shaft; and a second joint fitted to the other end of the power transmission shaft and fitted with a hub bearing. A vehicle drive shaft comprising:
A first fitting portion that is a fitting portion between the power transmission shaft and the first joint, a second fitting portion that is a fitting portion between the power transmission shaft and the second joint, and the second joint and the at least one fitting portion of the third fitting portion that is a fitting portion with the hub bearing is spline-fitted;
In the at least one spline-fitted fitting portion, the one spline tooth and the other spline tooth of the mutually fitted spline teeth are in contact with each other at a contact point. A drive shaft for a vehicle, wherein torsional rigidity is set by forming a predetermined torsion angle with respect to a rotation axis with one of the spline teeth of the other spline tooth .

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