JPH0791431A - Propeller shaft - Google Patents

Abstract

PURPOSE:To provide such an FRP propeller shaft that allows target fracture to start surely at axial compression impact load, while keeping high torsional strength. CONSTITUTION:A trigger part 3 which is the origin of fracture in a main body cylinder 1 at compression impact lad in the cylinder axial direction is provided in the main cylinder 1 in a propeller shaft formed by joining a metal joint 2 to the end of an FRP main body cylinder 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propeller shaft for automobiles and the like.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for weight reduction of automobiles for the purpose of improving fuel consumption from the viewpoint of energy saving. As one of the means, it is considered to replace the propeller shaft made of metal with that made of FRP (fiber reinforced plastic). At that time, there are various kinds of reinforcing fibers to be used, for example, carbon fibers, glass fibers, aramid fibers, etc. are being studied. Among them, CFRP using carbon fibers as reinforcing fibers is particularly preferable in terms of strength and elastic modulus. (Carbon fiber reinforced plastic) is considered to be influential.

A propeller shaft of an automobile is required to have a torsional strength of about 100 to 400 kgf · m because it is necessary to transmit a large torque generated from an engine. Conventional CFRP propeller shafts, particularly the main body cylinder thereof, have a stacking angle and a stacking structure thereof for transmitting a required torque, and a size of the shaft (as described in JP-A-2-236014, etc.). The inner diameter, outer diameter, and wall thickness), the type of reinforcing fiber used, the fiber content, etc. are used as parameters. By properly setting these design parameters, it is possible to achieve the torsional strength that is practically required as described above.

By the way, in recent years, various studies have been conducted on the safety in the event of an automobile collision. For example, research is being conducted to secure the safety of passengers by making a car body and the like into a crushable structure and effectively absorbing the impact energy at the time of a collision by a car body that gradually destroys.

In designing a propeller shaft made of FRP, if only high rigidity is pursued and a propeller shaft having too high rigidity against an axial impact load is used, the propeller shaft becomes a stub at the time of collision. ,
The effect of having a crushable body structure will be lost.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to
In the RP propeller shaft, while ensuring the high torsional strength required for automobiles, etc., it is possible to surely promote the necessary destruction against an axial impact load according to a crushable vehicle body etc. An object of the present invention is to provide a propeller shaft that can be used.

[0007]

In order to achieve the above object, a propeller shaft according to the present invention is a propeller shaft in which a metal joint is joined to an end portion of an FRP main body cylinder. The present invention is characterized in that a trigger portion is provided as a starting point of the main body cylinder breakage against a compressive impact load.

Here, the trigger portion is formed as follows, for example. The trigger portion is formed as a chamfered portion at the end of the main body cylinder, and the tip of the chamfered portion substantially abuts the metal joint.

Further, the trigger part has a lower adhesive layer shear strength with the matrix resin used for the FRP of the main body cylinder than the interlaminar shear strength of the FRP and has a layer thickness within the cylinder wall of the main body cylinder. It is formed by embedding a sheet-like material that is thinner than the thickness of a single layer of FRP of the main body cylinder having a laminated structure of reinforcing fibers.

This sheet material can be selected from a release film, a metal thin plate, a metal net, a woven fabric of organic fibers, a woven fabric of glass fibers, a woven fabric of aramid fibers and the like.

For example, the upper trigger portion is formed by embedding a release film, which extends annularly in the circumferential direction of the main body cylinder, in the cylinder wall of the main body cylinder. Alternatively, the trigger portion is formed by embedding a release film that extends in a band shape in the cylinder axis direction of the main body cylinder in the cylinder wall of the main body cylinder.

The main body cylinder may be made of carbon fiber reinforced plastic, and the trigger portion may be formed by disposing an aramid fiber reinforced layer or an organic fiber reinforced layer in the cylinder wall of the main body cylinder. it can. The orientation angle of the reinforcing fibers in the aramid fiber-reinforced layer or the organic fiber-reinforced layer is preferably ± 40 ° to ± 50 ° with respect to the axial direction of the main cylinder. Here, as the organic fiber, for example, polyester fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polyamide fiber or the like can be used.

Further, the trigger portion is formed by providing the main body cylinder with a convex portion in which the cylinder wall of the main body cylinder bulges outward and which extends annularly in the circumferential direction of the main body cylinder.

Further, in the trigger part, the main body cylinder is composed of a large diameter part, a small diameter part, and a conical cylinder part connecting the large diameter part and the small diameter part, and the trigger part is a cylinder shaft of the conical cylinder part. It can also be formed by making the directional buckling load smaller than the smaller one of the large axial diameter buckling load and the small axial buckling load.

[0015]

[Function] In such a propeller shaft, FR
At any part of the P-made main body cylinder, the chamfered portion, the buried sheet-like object, the annularly extending convex portion or the conical cylinder portion is provided with a trigger portion which is a starting point of the main body cylinder's destruction against a compressive impact load in the cylinder axial direction. It is formed. Therefore, when the main body cylinder is broken by the compressive load in the cylinder axial direction, the breakage is always started and progressed from this trigger portion, and the breakage is started with a smaller compressive load than other parts of the main body cylinder. In addition, each of these trigger portions has a structure in which the torsional strength of the main body cylinder is not substantially reduced.

The torsional strength required for a propeller shaft for an automobile can be achieved by optimizing the design of the main body cylinder as described above, and therefore the provision of the above-mentioned trigger portion ensures the required torsional strength. With respect to the compressive shock load in the cylinder axis direction, the main body cylinder can be surely started to be broken as necessary, and the main body cylinder itself can effectively absorb the impact energy.

[0017]

Embodiments of the propeller shaft of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a propeller shaft according to a first embodiment of the present invention. In the figure, 1 indicates a FRP main body cylinder, and 2 indicates a metal joint which is joined to the end of the main body cylinder 1 by press fitting.

In this embodiment, the trigger portion 3 which is the starting point of breakage of the main body cylinder 1 against the axial compressive impact load is the main body cylinder 1
Is formed by the chamfered portion 4 at the edge. The tip 4a of the chamfered portion 4 is substantially in contact with the joint 2.

With such a structure, when a compressive shock load in the cylinder axis direction is applied, a large surface pressure is instantaneously applied to the tip 4a of the chamfered portion 4 which is in contact with a small contact area, and the contact pressure is always required. Destruction starts and progresses from the tip 4a.

Since the chamfered portion 4 intentionally weakens the strength only against the compressive load in the cylinder axial direction at the end edge of the main body cylinder 1, the strength in the cylinder axial direction at other portions of the main body cylinder 1 is increased. , It has virtually no effect on the elastic modulus, especially on the torsional strength. Therefore, the desired compressive fracture is reliably started while ensuring the required torsional strength.

The fracture starting load for compression can be set to an optimum load by setting the angle and area of the chamfered portion 4, the contact area of the tip 4a, and the like.

The chamfering direction may be the direction shown in FIG. That is, the chamfered portion 1 serving as the trigger portion 11
2, the outer diameter side may be formed by dropping the shoulder, and the tip 12a formed on the inner diameter side may be brought into contact with the joint 2.

FIG. 3 shows a propeller shaft according to a second embodiment of the present invention. Metal joints 22a and 22b are joined to both ends of the FRP main body cylinder 21 by press fitting. In the wall thickness of the main body tube 21, a release film 23 that is annularly extended in the circumferential direction of the main body tube is embedded.
This release film 23 can be embedded by inserting and winding a predetermined release film during lamination of the reinforcing layer when the FRP main body cylinder 21 is manufactured.

In the present embodiment, the release films 23 are arranged with a same diameter in the axial direction of the main body cylinder 21 at a plurality of intervals, substantially over the entire length. One of the metallic joints 22a and 22b press-fitted into both ends 22
The a is abutted against the end surface of the main body cylinder 21 at a portion on the inner diameter side of the release film 23 disposed portion, and the other joint 22b.
Is in contact with the end surface of the main body cylinder 21 at a portion on the outer diameter side of the release film 23 disposed portion. Then, in the other joint 22b, a relief 2 formed of an annular space is provided at a portion facing the portion on the inner diameter side of the release film 23 arrangement portion.
4 are formed.

In such a propeller shaft,
When viewed in the radial direction, a shear fracture surface is formed with the release film 23 as a boundary. For example, in the structure described above, when an axial compressive load is applied, the main body tube 21 receives a compressive load from one joint 22a from an abutting portion on the inner diameter side of the release film 23 disposed portion, and the other joint 22a. From 22b, a compressive load is applied from the contact portion on the outer diameter side of the release film 23 arrangement portion. As a result, a shearing load is applied to the release film arranging portion, and by making it easy to break at this portion, the breaking always starts and progresses from this portion.

This breaking start load can also be freely set to a target value depending on the size of the release film 23, the arrangement pitch, and the like.

The material of the release film is not particularly limited, but, for example, Teflon film, polyethylene terephthalate film and the like are suitable. Incidentally, in order to optimize the function as the trigger portion, a release treatment such as applying a release agent to the surface of the film may be performed depending on the case.

Further, in the above embodiment, the release film 23
Although it is arranged intermittently over the entire length of the main body cylinder 21, other arrangement forms may be used. For example, as shown in FIG. 4, a release film 32 having a relatively wide width may be provided at a suitable position (for example, the central part) in the axial direction of the main body cylinder 31. With such a structure, it is possible to initiate a desired fracture without substantially lowering the torsional strength.

Further, in the above embodiment, the release film 23
Alternatively, although 32 is arranged annularly in the circumferential direction of the main body cylinder, but is arranged intermittently over the entire length, it is also possible to embed a release film extending in a band shape in the cylinder axis direction of the main body cylinder. As shown in FIG. 5, a release film 34 extending in a belt shape in the axial direction of the main body cylinder 33 can be formed by embedding it at an appropriate pitch in the circumferential direction of the main body cylinder. In addition, in FIG. 5, for comparison, a release film 23 extending in an annular shape in the circumferential direction is also shown.

Further, as described above, in addition to the release film, various sheets selected from a metal thin plate, a metal net, a woven material of organic fibers, a woven material of glass fibers, a woven material of aramid fibers and the like. The trigger portion can be formed by embedding the material. For example, as shown in FIG.
Between the fiber-reinforced layers 35a and 35b made of the FRP layer, the orientation angle of the reinforcing fibers is ± 40 ° to ± with respect to the cylinder axis direction of the main body cylinder.
The trigger portion can be formed by disposing the aramid fiber reinforced layer 36 having an angle of 50 °.

FIG. 7 shows a main body cylinder of a propeller shaft according to a third embodiment of the present invention. FRP body tube 41
A cylindrical wall of the main body cylinder 41 bulges outwardly (in the illustrated example, it bulges outward, but may be inside), and a convex portion 42 that extends annularly in the circumferential direction of the main body cylinder is formed at an axially intermediate portion of the above. Has been done. The convex portion 42 can be easily formed, for example, by winding the annular foam 43 or an appropriate resin around the mandrel when the FRP main body cylinder 41 is molded.

The protrusion 42 can have a torsional strength equal to or higher than that of the other parts, but has a lower load resistance against the compressive load than the other parts. It reliably becomes the starting point of fracture against the impact load in the compression direction without lowering the overall torsional strength.

FIG. 8 shows a main body cylinder of a propeller shaft according to a fourth embodiment of the present invention. The main body cylinder 51 includes a large-diameter portion 52, a small-diameter portion 53, and a conical cylinder portion 54 connecting the both.
The conical tubular portion 54 constitutes a trigger portion which is a starting point of destruction against a compressive impact load in the tubular axial direction.

Since the conical cylindrical portion 54 has a higher torsional strength than at least the small diameter portion 53, in this embodiment as well,
A trigger portion for starting fracture against a compressive impact load is reliably formed without reducing the torsional strength of the entire main body cylinder 51.

Further, in this embodiment, since the mandrel 55 for molding the main body cylinder 51 only needs to have a double diameter shape, no special step for forming the trigger portion is required, and the productivity is high. high.

The compressive breaking load can be freely designed to a target value by appropriately setting the taper angle, the length, etc. of the conical cylindrical portion 54.

As the matrix resin constituting the FRP propeller shaft of the present invention, a thermosetting resin such as an epoxy resin, a phenol resin, a polyimide resin, a vinyl ester resin or an unsaturated polyester is used, but other resins such as, for example, It may be a thermoplastic resin such as polyamide, polyamide, polyetherimide or the like.

The reinforcing fiber is not limited to carbon fiber, but glass fiber, aramid fiber, or the like can be used, and these can be used in combination.

In the propeller shaft of the present invention, a seal material may be arranged at an appropriate position (for example, each member end position) between the FRP main body cylinder and the metal joint. A resin, a ring-shaped elastic body, a film or the like is suitable as the sealing material. By disposing such a sealing material, it is possible to more reliably prevent entry of water and the like and prevent corrosion of the joint portion.

Further, when the metal joint is press-fitted, it is necessary to grip the joint with the press-fitting jig. However, in order to securely grip and to prevent the joint from being damaged by the pressure input, the joint is press-fitted. It is preferable to provide a locking or engaging portion for the tool. Such a locking or engaging portion can be formed by forming a step portion or a groove portion at an appropriate position on the outer surface of the joint.

Further, in order to reduce the press-fitting force of the metal joint as much as possible and to press-fit efficiently, the following method is effective. Lower the temperature of the joint and raise the temperature of the end of the FRP body cylinder to press fit. Use the adhesive as a lubricant. Use a volatile liquid lubricant that does not remain after press fitting.

Further, it is possible to adjust the balance after completion of the propeller shaft by providing a balance weight mounting portion on the metal joint and adding an appropriate balance weight to the mounting portion by welding or the like. If a cooling fin is formed around the balance weight mounting portion, especially on the outer surface of the joint between the balance weight mounting portion and the FRP main body cylinder to be joined, welding at the time of joining the balance weight is performed. It is possible to prevent heat from being transferred to the FRP main body cylinder side.

[0043]

According to the present invention, the main body cylinder of the FRP propeller shaft is provided with the trigger portion which is the starting point of the destruction against the compressive impact load in the axial direction of the cylinder, and the compression fracture is surely started and progressed from the trigger portion. As a result, it is possible to obtain a desirable mode of destruction required at the time of a collision or the like while ensuring a high torsional strength required for automobiles and the like.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an FRP propeller shaft according to a first embodiment of the present invention.

FIG. 2 is a FR showing a shape of a trigger portion according to a modification of FIG.
It is a fragmentary sectional view of a P-made main body cylinder.

FIG. 3 is a partial sectional view of an FRP propeller shaft according to a second embodiment of the present invention.

FIG. 4 is a FR showing the shape of a trigger portion according to the modified example of FIG.
It is a fragmentary sectional view of a P-made main body cylinder.

5 is a schematic perspective view of an FRP main body cylinder showing a shape of a trigger portion according to another modification of FIG. 3. FIG.

6 is a partial cross-sectional view of an FRP main body cylinder showing the shape of a trigger portion according to still another modification of FIG.

FIG. 7 is a partial cross-sectional view of a main body cylinder of an FRP propeller shaft according to a third embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a main body cylinder of an FRP propeller shaft according to a fourth embodiment of the present invention.

[Explanation of symbols]

1, 21, 31, 33, 37, 41, 51 FRP main body tube 2, 22a, 22b Metal joint 3, 11 Trigger part 4, 12 Chamfer part 4a, 12a Tip 23, 32, 34 Release film 24 Escape 35a , 35b CFRP layer 36 Aramid fiber reinforced layer 42 Convex portion 52 Large diameter portion 53 Small diameter portion 54 Conical cylindrical portion 55 Mandrel

Claims (12)

[Claims] 1. A propeller shaft in which a metal joint is joined to an end portion of an FRP main body cylinder, wherein the main body cylinder is provided with a trigger portion which is a starting point of main body cylinder breakage against a compressive impact load in the cylinder axial direction. Propeller shaft characterized by 2. The propeller shaft according to claim 1, wherein the trigger portion is formed as a chamfered portion of an end edge of the main body cylinder, and a tip of the chamfered portion substantially abuts on a metal joint. 3. The trigger part has a bond strength with the matrix resin used for the FRP of the main body cylinder in the cylinder wall of the main body cylinder lower than the interlaminar shear strength of the FRP, and the layer thickness thereof. 2. The propeller shaft according to claim 1, wherein the propeller shaft is formed by burying a sheet-shaped material that is thinner than the thickness of a single layer of FRP of the main body cylinder having a laminated structure of reinforcing fibers. 4. The propeller shaft according to claim 3, wherein the sheet-like material is one selected from a release film, a metal thin plate, a metal net, a fabric of organic fibers, a fabric of glass fibers, and a fabric of aramid fibers. . 5. The propeller shaft according to claim 3, wherein the trigger portion is formed by embedding a release film, which extends annularly in a circumferential direction of the main body cylinder, in a cylinder wall of the main body cylinder. 6. The propeller shaft according to claim 3, wherein the trigger portion is formed by embedding a release film extending in a strip shape in the cylinder axis direction of the main body cylinder in the cylinder wall of the main body cylinder. 7. The main body cylinder is made of carbon fiber reinforced plastic, and the trigger portion is formed by disposing an aramid fiber reinforced layer in the cylinder wall of the main body cylinder.
Or 4 propeller shafts. 8. The orientation angle of the aramid fibers in the aramid fiber reinforced layer is ± 40 ° to ± with respect to the cylinder axis direction of the main body cylinder.
8. The propeller shaft of claim 7, in the range of 50 °. 9. The propeller shaft according to claim 3, wherein the main body cylinder is made of carbon fiber reinforced plastic, and the trigger portion is formed by disposing an organic fiber reinforced layer in the cylinder wall of the main body cylinder. 10. The orientation angle of the organic fibers in the organic fiber reinforced layer is ± 40 ° to ± 50 ° with respect to the cylinder axis direction of the main body cylinder.
10. The propeller shaft of claim 9 in the range. 11. The trigger portion is formed by providing the main body cylinder with a convex portion in which the cylinder wall of the main body cylinder bulges outward and which extends annularly in the circumferential direction of the main body cylinder. Propeller shaft. 12. The main body cylinder comprises a large diameter part, a small diameter part, and a conical cylinder part connecting the large diameter part and the small diameter part, and the trigger part comprises a buckling load in the cylinder axial direction of the conical cylinder part. Is smaller than the smaller one of the large axial diameter buckling load and the small axial buckling load, the propeller shaft according to claim 1.