JPH09295517A - Propeller shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten an impact on an occupant so as to ensure safety by providing a release device for releasing fixing of an inner ring by a fixing device when axial load above a designated value is applied to a propeller shaft. SOLUTION: When the force in the direction of compressing a propeller shaft is applied in the axial direction of the propeller shaft through a coupling 40, radial component force is generated at the respective inclined surfaces 48b, 48c of the side wall on the counter-shaft end side of a clip groove 48b to force the clip 28 to be reduced in diameter. Accordingly, when the axial force above a designated value is applied to the propeller shaft, taking the angles θB1 , θB2 and the radial elastic force of the clip 28 into consideration, the clip 28 is reduced in diameter to permit a serration shaft 26, that is, also the propeller shaft 28 to move in the axial direction to the clip 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a propeller shaft (propelling shaft) of an automobile, and more particularly, to alleviate an impact on an occupant even when an excessive axial load acts on the propeller shaft at the time of collision of the automobile. To ensure safety.

[0002]

2. Description of the Related Art In front-mounted engine rear-wheel drive vehicles,
The engine, clutch, and transmission are in front, the reduction gear unit,
Since the drive axle is at the rear, a propeller shaft is used for power transmission between them. The propeller shaft has a universal joint and a sliding joint, and has a structure capable of responding to changes in length and angle due to changes in relative positions of the transmission and the reduction gear device. As the propeller shaft, a 2-joint type, a 3-joint type, a 4-joint type, etc. are used depending on the vehicle structure and required performance.

In recent years, a constant velocity universal joint (hereinafter simply referred to as a joint) is attached to a propeller shaft in order to improve the NVH performance of an automobile.
Are being used more and more. Above all, the sliding joint has a small sliding resistance and contributes greatly to improving NVH performance.

A propeller shaft for power transmission of an automobile is arranged in the front-rear direction of the vehicle mainly by a combination of a fixed joint and a sliding joint between a transmission (transmission) / a differential (a final reduction gear). In particular, the sliding joint has a function of absorbing movement in the longitudinal direction of the power plant system such as an engine. This amount of movement varies depending on the type of vehicle, suspension device, etc., but in the case of independent suspension, for example, it is considered that MAX is about 20 to 25 mm in the steady running state. However, there are cases in which the amount of sliding of the constant velocity universal joint is increased more than necessary in the steady running state, assuming an unforeseen situation such as a car collision.

[0005]

Safety is one of the reasons for increasing the amount of sliding of the joint. That is, when the amount of sliding of the joint is small, it is conceivable that when an unexpected situation such as a vehicle collision accident occurs, a large force is applied to the propeller shaft beyond the sliding limit of the joint and a large impact force acts on the occupant. In order to avoid this, it is sufficient to secure a sliding amount in the joint so that the propeller shaft does not become a heavy rod as described above, but the sliding amount of the joint is naturally limited due to design / manufacturing restrictions. In particular, for a propeller shaft used at high speed rotation, increasing the sliding amount of the joint leads to an increase in weight and is not preferable in terms of rotational balance and vibration force.

Therefore, an object of the present invention is to reduce the impact on the occupant and secure safety for occupant protection without increasing the sliding amount of the joint more than necessary.

[0007]

A propeller shaft according to the present invention is a propeller shaft having a constant velocity universal joint attached to both ends of an intermediate shaft, wherein an inner ring of the constant velocity universal joint is fixed in the axial direction of the propeller shaft. And a releasing device for releasing the fixation of the inner ring by the fixing device when an axial load exceeding a predetermined value is applied to the propeller shaft.

The fixing device fixes the inner ring of the constant velocity universal joint in the axial direction by mounting the clip in the clip groove provided on the propeller shaft, and the releasing device clips when the axial load exceeding a predetermined value acts on the propeller shaft. Slip out of the clip groove.

[0009] A clip groove provided on the outer peripheral surface of the propeller shaft is mounted with a clip whose diameter can be expanded / contracted by elastic deformation and brought into contact with the end surface of the inner ring to fix the inner ring axially. When the device is adopted, the releasing device is configured by forming slopes having inclination angles corresponding to each other on the side wall of the clip groove on the side opposite the shaft end and the side surface of the clip in contact with the side wall.

If the inclination angle θ _A is 20 ° or less, the radial component force may be too large, and the diameter of the clip may be unnecessarily increased. Since it is difficult to expand the diameter of the
It is preferable to set the angle <θ _A <45 °.

If the contour of the side wall on the non-axial end side is made up of the sloped portion occupying the bottom side of the groove and the curved portion connected to the sloped portion, the clip that has begun to slip out can be suddenly ejected thereafter. it can.

The inner ring is fixed in the axial direction by interposing a clip whose diameter can be expanded / contracted by elastic deformation between the clip groove formed on the outer peripheral surface of the propeller shaft and the clip groove formed on the inner peripheral surface of the inner ring. When the fixing device configured as described above is adopted, the releasing device includes, as a releasing device, a contour of the side wall of the clip groove of the inner ring on the side opposite to the shaft end, from a portion that abuts the clip in a state of being expanded in diameter and engaged with the clip groove. The clip groove has a first slope facing the groove bottom and a second slope facing the inner peripheral surface from the portion.

[0013] In this case, it is preferable to set the relationship between the inclination angle theta _B2 between the inclination angle theta _B1 of the first inclined surface second slope in θ _B1 ≦ θ _B2.

Further, if the contour of the side wall of the clip groove on the side opposite to the axial end has a curved portion that smoothly connects to the cross-sectional shape of the clip, the slip-out of the clip becomes smooth.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a two-joint type propeller shaft (10) consisting of an intermediate shaft (20) and joints (30, 40) at both ends thereof. A hollow steel tube is generally used for the intermediate shaft (20), but a composite propeller shaft in which the intermediate shaft (20) is made of a composite material such as fiber reinforced plastic is also known.

The joint (30) on the right side of FIG. 1 is a double offset type sliding joint, and as shown in FIG.
An inner ring (31) having an outer spherical surface having a linear ball groove formed parallel to the axial direction, an outer ring (32) having a cylindrical inner peripheral surface having a linear ball groove formed parallel to the axial direction, and an axial direction. The cage (33), which is in contact with the outer spherical surface of the inner ring (31) and the cylindrical inner peripheral surface of the outer ring (32) with the offset inner spherical surface and outer spherical surface, is interposed between the ball groove of the inner ring and the ball groove of the outer ring. The torque transmission balls (34) positioned and held by the cage (33) are the main constituent elements, and the openings are covered with boots (35) for preventing the infiltration of dust, water and the like. The outer ring (32) has a flange (36) for connecting with other elements of the power transmission system. The inner ring (31) has a serration hole (37), and the intermediate shaft (2)
It is connected to the serration shaft (21) at the end of (0).

As shown in FIG. 2B, an annular clip groove (2) formed on the outer peripheral surface of the serration shaft (21).
2, 23) with a pair of clips (24, 25) attached,
These clips (24, 25) are brought into contact with the end faces of the inner ring (31) on both sides in the axial direction to position the inner ring (31) in the axial direction. Each clip (24, 25) is a so-called C-shaped clip in which a part of the ring is divided, and when it is mounted in the clip groove (22, 23), it is forcibly elastically deformed to be expanded in diameter. Serration axis in the state (21)
From the shaft end of each to the respective clip grooves (22, 23).

Regarding the shaft end side, both the clip (25) and the clip groove (23) are the same as usual ones. For the clip (24) on the non-axial end side, see FIG.
As shown in an enlarged view in (c), the side wall (22a) of the clip groove (22) on the side opposite to the shaft end is inclined by an angle θ _{A with} respect to the axis of the serration shaft (21). The side surface (2) of the clip (24) on the side corresponding to this inclined side wall (22a)
4a) is also provided with a slope portion (24b) inclined by an angle θ _{A with} respect to the axis of the serration shaft (21).

Thus, the inclined side wall (22a) of the clip groove (22) and the inclined surface portion (2) of the side surface of the clip (24).
Since 4b) are in contact with each other, when an axial force acts on the serration shaft (21), the radial component force acts in a direction to expand the diameter of the clip (24) (see the chain double-dashed line). Therefore, in consideration of the angle θ _A and the elastic force of the clip (24) in the radial direction, when the axial force exceeding the predetermined value acts on the serration shaft (21), the diameter of the clip (24) is expanded. The serration shaft (21) may be allowed to move axially with respect to the clip (24). This means that the distance between the joints (30, 40) becomes shorter, and the propeller shaft (1
0) Overall, the total length will be reduced.

Specifically, the angle θ _A is 20 ° <θ _A <45
It is desirable to set in the range of °. If θ _A is 20 ° or less, the radial component force may be too large and the clip (24) may be unnecessarily expanded in diameter, while θ _A is 45 °.
When it becomes above, the radial component force becomes small and the clip (2
This is because it is difficult to expand the diameter of 4).

Further, as shown in FIG. 2D, the contour of the side wall (22a) of the clip groove (22) on the side opposite to the shaft end has a straight line portion (m) occupying the bottom side of the clip groove (22). The clip (24) which has begun to come off can be made to come out at a stretch later by comprising the curved portion (n) connected to the sloped portion. That is, when an excessive axial load acts on the propeller shaft (10) and the axial component force acts to expand the diameter of the clip (24), the initial pull-out load is large, but when the pull-out begins, the propeller shaft (10) suddenly comes off.

The flange (3) of the outer ring (32) is provided to prevent leakage of the lubricating grease filled inside the joint (30).
A cap (38) is attached to the opening on the side 6). The cap (38) is provided with a relief portion (39) that allows the serration shaft (21) to enter.

Next, the joint (40) on the left side of FIG. 1 is a bar field type fixed joint, and as shown in FIG.
Inner ring (41) having an outer spherical surface with arc-shaped ball grooves
And an outer ring (4 having an inner spherical surface formed with an arc-shaped ball groove)
2), a cage (43) having an outer spherical surface of the inner ring and a concentric inner spherical surface and an outer spherical surface in contact with the inner spherical surface of the outer ring, and an inner ring (4)
1) and the torque transmission ball (44) positioned in the arc-shaped ball groove offset in the axial direction of the outer ring (42) and positioned and held by the cage are the main constituent elements, and the opening part infiltrate dust and water. It is covered with boots (45) to prevent The outer ring (42) has a flange (46) for connecting with other elements of the power transmission system. The inner ring (41) has a serration hole (47), and the intermediate shaft (2
It is connected to the serration shaft (26) at the end of (0).

As shown in FIG. 3 (b), a clip (28) is mounted in an annular clip groove (27) formed in the serration shaft (26), and the clip (28) allows the shaft of the inner ring (41) to be mounted. Directional positioning is performed. The clip (28) is a so-called C-shaped clip in which a part of the circular ring is divided, and when mounted, it is forcibly reduced in diameter by utilizing elasticity to clip the clip groove (27) of the serration shaft (26). ), The inner ring (41) is moved along the serration shaft (26), and when the clip (28) matches the position of the clip groove (48) of the inner ring (41), the inner ring (41) is expanded by elastic force. Fit into clip groove (48).

The clip groove (48) of the inner ring (41) is shown in FIG.
The cross-sectional shape is shown as enlarged in (c). That is, the side wall (48a) on the shaft end side extends perpendicularly to the axis, that is, in the radial direction, whereas the side wall on the opposite shaft end side is formed by the inclined surfaces (48b, 48c). The inclined surfaces (48b, 48c) are continuous with each other at a portion (p) contacting the clip (28), and the inclined surface (48b) on the groove bottom side of the clip groove (48) forms an angle θ with the radial direction. _B1
The inclined surface (48c) on the axial center side is inclined at an angle θ _{B2 with} respect to the radial direction.

The relationship between the angles θ _B1 and θ _B2 is θ _B1 ≤ θ _B2 ,
Moreover, it is desirable to set 20 ° <θ _B1 <45 °.
This is because the clearance between the clip (28) and the clip groove is usually reduced on the inclined surface (48b) having the inclination angle θ _B1 to reduce the axial movement amount of the inner ring (41), but the excessive axial direction inclined surface (48 of the inclination angle theta _B2 when the force is applied
It is intended to get out at once in c). The range of the inclination angle θ _B1 is set as described above. When the angle is smaller than 20 °, the radial component force becomes small and it becomes difficult to reduce the diameter of the clip (28). This is because the force may become too large and the diameter of the clip may be unnecessarily reduced.

Further, in order to make it easy for the clip (28) to come out of the clip groove (48) when an excessive axial load is applied, as shown in FIG. 3 (d), the clip groove (48) Desirably, the contours of the side walls (48b, 48c) are curves that smoothly connect to the cross-sectional shape of the clip (28).

Since the clip groove (48) has such a cross-sectional shape, it is oriented so as to compress the propeller shaft (20) in the axial direction of the propeller shaft (20) via the joints (30, 40). When a force acts, the inclined surfaces (48b, 48b) of the side wall of the clip groove (48) on the side opposite to the shaft end.
In c), a radial component force is generated and acts to reduce the diameter of the clip (28). Therefore, the angles θ _B1 , θ _B2
And the elastic force of the clip (28) in the radial direction, the axial force exceeding a predetermined value is applied to the propeller shaft (2).
0), causing the clip (28) to contract to allow the serration shaft (26) and thus also the propeller shaft (20) to move axially relative to the clip (28). can do. This means that the distance between the joints (30, 40) becomes shorter, and the overall length of the propeller shaft (10) is reduced.

[0030]

In the propeller shaft of the present invention, when an excessive axial force exceeding the sliding limit of the constant velocity universal joint is applied, the releasing device operates to release the fixation of the inner ring of the constant velocity universal joint. Therefore, relative movement in the axial direction is allowed between the constant velocity universal joint and the intermediate shaft of the propeller shaft, and the distance between the constant velocity universal joints at both ends of the propeller shaft is reduced. Therefore, it is possible to reduce a shock when an excessive axial force is applied to the vehicle body, and thereby to reduce an impact force applied to the occupant.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a propeller shaft showing an embodiment of the present invention.

FIG. 2A is an enlarged view of one joint. (B)
(C) and (d) are enlarged views of a clip groove portion.

FIG. 3A is an enlarged view of the other joint. (B)
(C) and (d) are enlarged views of a clip groove portion.

[Explanation of symbols]

 10 Propeller shaft 20 Intermediate shaft 21,26 Serration shaft 22,23,27 Clip groove 24,25,28 Clip 22a Non-shaft end side wall 24b Slope face 30 Constant velocity universal joint 38 Cap 39 Relief portion 40 Constant velocity universal joint 48 Reversed Shaft end side sidewalls 48b, 48c Slope portion

Claims (8)

[Claims] 1. A propeller shaft in which constant velocity universal joints are attached to both ends of an intermediate shaft, and a fixing device for fixing an inner ring of the constant velocity universal joint in an axial direction of the propeller shaft,
A propeller shaft comprising: a releasing device that releases the fixation of the inner ring by the fixing device when an axial load exceeding a predetermined value acts on the propeller shaft. 2. The fixing device axially fixes an inner ring of a constant velocity universal joint by mounting a clip in a clip groove provided in a propeller shaft, and the releasing device applies a load in the axial direction exceeding a predetermined value to the propeller shaft. The propeller shaft according to claim 1, wherein when actuated, the clip is pulled out from the clip groove. 3. A clip groove provided on the outer peripheral surface of the propeller shaft is provided with a clip that can be expanded or reduced in diameter by elastic deformation and is brought into contact with the end surface of the inner ring, and the side wall on the opposite shaft end side of the clip groove. The propeller shaft according to claim 2, wherein the side surface of the clip that is in contact with the side wall is formed with slopes having inclination angles corresponding to each other. 4. The propeller shaft according to claim 3, wherein the inclination angle θ _{A is set} to 20 ° <θ _A <45 °. 5. The propeller shaft according to claim 3, wherein the contour of the side wall on the opposite shaft end side is composed of the sloped portion occupying the bottom side of the groove and a curved portion continuous with the sloped portion. 6. An inner ring is axially arranged by interposing a clip, which can be expanded / contracted by elastic deformation, between a clip groove formed on the outer peripheral surface of the propeller shaft and a clip groove formed on the inner peripheral surface of the inner ring. A first sloped surface that is fixed and extends from the portion of the side wall on the opposite axial end side of the clip groove of the inner ring that abuts the clip in the state of being expanded and engaged with the clip groove, to the groove bottom of the clip groove, The propeller shaft according to claim 2, wherein the propeller shaft comprises a second inclined surface extending from the portion toward the inner peripheral surface. 7. A propeller shaft according to claim 6 which is set as the inclination angle theta _B1 of the first slope of the relationship between the inclination angle theta _B2 of the second slope to θ _B1 ≦ θ _B2. 8. The propeller shaft according to claim 6, wherein a contour of the clip groove on the side opposite to the shaft end has a curved portion that smoothly connects to the cross-sectional shape of the clip.