JP2020159534A - FRP composite molded product - Google Patents

Abstract

To provide an FRP composite molded product capable of preventing damage of an FRP cylinder and also improving connection strength between the FRP cylinder and a joint member.SOLUTION: An FRP composite molded product has an FRP cylinder having a plurality of FRP layers, and a joint member having a serration part press-fitted into the inner peripheral surface of the FRP cylinder. The serration part has an inside region including a valley bottom part of the serration part, and an outside region including a crest part of the serration part. The FRP cylinder has a 0° layer in which the inside region of the serration part is press-fitted and that has a fiber direction parallel to the axial direction of the FRP cylinder, and an angular layer in which the outside region of the serration part is press-fitted and that has a fiber direction obliquely or orthogonal to the axial direction of the FRP cylinder.SELECTED DRAWING: Figure 3

Description

The present invention relates to an FRP composite molded product.

Patent Document 1 discloses a power transmission shaft in which end members are coupled to both ends of a tubular member made of fiber reinforced plastic. At least one of the end members has a locking portion (serration) formed on the outer peripheral surface of the joint portion with the tubular member. The reinforcing fibers of the tubular member are wound around the end member on the outer peripheral surface so as to form a plurality of layers, and the fiber bundles constituting the innermost layer are arranged so as not to intersect with each other, and the circumference with respect to the end member is provided by the locking portion. Relative movement in the direction is restricted. The innermost layer of the tubular member is composed of helical windings in which fiber bundles are arranged in parallel with each other and are continuous over the entire length. The fiber bundles arranged by helical winding are arranged in parallel with each other in the same layer, and are formed as an angular layer having a predetermined angle (arrangement angle) with respect to the axial direction of the end member.

Japanese Unexamined Patent Publication No. 2004-293714

However, the conventional FRP drive shaft (FRP composite molded product) including Patent Document 1 is a joining method in which serrations are press-fitted into an FRP cylinder having a laminated structure, and a layer in which serrations are caught when torque is transmitted. May peel off inward and induce premature breakage of the joint. On the other hand, if the amount of serrations biting into the FRP cylinder is increased in order to increase the joint strength, the press-fitting load becomes too large and the FRP cylinder is damaged.

The present invention has been made based on the above awareness of the problems, and an object of the present invention is to provide an FRP composite molded product capable of preventing damage to the FRP cylinder and improving the bonding strength between the FRP cylinder and the joint member. To do.

The FRP composite molded product of the present embodiment has an FRP cylinder having a plurality of FRP layers and a joint member having a serration portion press-fitted into the inner peripheral surface of the FRP cylinder, and the serration portion is the serration. The FRP cylinder has an inner region including the valley bottom portion of the portion and an outer region including the peak portion of the serration portion, and the FRP cylinder is press-fitted with the inner region of the serration portion and is in the axial direction of the FRP cylinder. It is characterized by having a 0 ° layer having parallel fiber directions and an angular layer having a fiber direction obliquely or orthogonal to the axial direction of the FRP cylinder while the outer region of the serration portion is press-fitted. There is.

The gap in the inner region of the serration portion may be filled with the 0 ° layer.

The gap in the inner region of the serration portion may be filled with the 0 ° layer and an adhesive.

The adhesive may fill the valley bottom portion of the gap in the inner region, and the 0 ° layer may fill the portion of the gap in the inner region excluding the valley bottom portion.

When the height of the serration portion is defined as H and the biting height of the 0 ° layer with respect to the inner region is defined as h1, 0.25 <h1 / H <0.50 may be satisfied.

When the height of the serration portion is defined as H and the biting height of the angular layer with respect to the outer region is defined as h2, 0.05 <h2 / H <0.25 may be satisfied.

The angular layer may consist of a 30-150 ° layer having a fiber direction orthogonal to the axial direction of the FRP cylinder.

According to the present embodiment, it is possible to provide an FRP composite molded product capable of preventing damage to the FRP cylinder and improving the bonding strength between the FRP cylinder and the joint member.

It is a perspective view which shows the structure of the FRP drive shaft by 1st Embodiment. It is the figure which looked at the joint part of the FRP cylinder and end joint from the axial direction. It is an enlarged view of the main part of FIG. It is a conceptual diagram which shows an example of the relationship between the height of a serration part, the biting height of a 0 ° layer with respect to an inner region, and the biting height of a 90 ° layer with respect to an outer region. It is a figure which looked at the joint part of the FRP cylinder and the end joint from the axial direction in the FRP drive shaft by 2nd Embodiment.

<< First Embodiment >>
FIG. 1 is a perspective view showing the configuration of an FRP drive shaft (FRP composite molded product) 10 according to the first embodiment.

The FRP drive shaft 10 is configured by connecting end joints (joint members) 30 to both ends of the FRP cylinder 20. Since the two end joints 30 have the same configuration, they will be described with the same reference numerals. It is also possible to connect the end joint 30 only to one end of the FRP cylinder 20.

The FRP cylinder 20 has a plurality of FRPs (Fiber Reinforced Plastics) obtained by winding a plurality of prepregs obtained by impregnating a thermosetting resin sheet with reinforcing fibers (for example, carbon fibers) into a tubular shape and heat-curing them. ) Has a layer. There is a degree of freedom in the manufacturing method of the FRP cylinder 20, and various design changes are possible. For example, an FRP cylinder 20 may be formed by injection molding a short carbon fiber dispersed in a resin. The diameter (inner diameter) of the inner peripheral surface 21 and the diameter (outer diameter) of the outer peripheral surface 22 of the FRP cylinder 20 are substantially constant over the entire length in the axial direction. The diameter (outer diameter) of the outer peripheral surface 22 can be increased only near the joint (for example, both ends where the end joint 30 is press-fitted) in order to prevent the FRP cylinder 20 from being damaged by press-fitting the end joint 30. Is.

The end joint 30 is made of a metal material such as steel, and has a rod portion 31 formed in a solid or hollow rod shape. The end joint 30 has a serration portion 32 that is press-fitted into the inner peripheral surface 21 of the FRP cylinder 20 on the same axis as the rod portion 31. The serration portion 32 includes, for example, triangular tooth serrations and involute serrations. The serration portion 32 can be formed in a series in the axial direction of the end joint 30 as shown in the illustrated example, or may be formed by being divided into a plurality of parts along the axial direction of the end joint 30.

Although not shown, an outer member (outer collar) may be joined to the outer peripheral surface 22 of the FRP cylinder 20 by interposing an adhesive depending on the application of the FRP drive shaft 10.

FIG. 2 is a view of the joint portion between the FRP cylinder 20 and the end joint 30 as viewed from the axial direction. FIG. 3 is an enlarged view of a main part of FIG.

As shown in FIG. 2, the serration portion 32 of the end joint 30 is press-fitted into the inner peripheral surface 21 of the FRP cylinder 20.

As shown in FIG. 3, the serration portion 32 of the end joint 30 has an inner region (inner diameter region) 32I including the valley bottom portion of the serration portion 32 and an outer region (outer diameter region) 32O including the peak portion of the serration portion 32. And have.

As shown in FIG. 3, the FRP cylinder 20 (inner peripheral surface 21) has a fiber direction parallel to the axial direction of the FRP cylinder 20 while the inner region 32I of the serration portion 32 of the end joint 30 is press-fitted. The ° layer 21I and the outer region 32O of the serration portion 32 of the end joint 30 are press-fitted and have a 90 ° layer (angle layer) 21O having a fiber direction orthogonal to the axial direction of the FRP cylinder 20. Of the FRP cylinder 20, there is a degree of freedom in the configuration of the FRP layer forming the inner layer side (lower layer side) of the 90 ° layer 21O, and various design changes are possible.

The 0 ° layer 21I is formed by, for example, winding a 0 ° prepreg whose fiber direction is aligned with the axis direction of the FRP cylinder 20 in a tubular shape and thermosetting it. In the example of FIG. 3, the 0 ° layer 21I is drawn so as to be formed over two layers, but this is for convenience of drawing. That is, the number of layers of the 0 ° layer 21I (the number of 0 ° prepregs and the number of plies used to form the 0 ° layer 21I) has a degree of freedom, and various design changes are possible. Moreover, as will be described in detail later, the two-layer 0 ° layer 21I of FIG. 3 has both a portion where the inner region 32I of the serration portion 32 of the end joint 30 is press-fitted and a portion extruded by the press-fitting. It is drawn with a concept that includes.

The 90 ° layer 21O is formed by, for example, winding a 90 ° prepreg whose fiber direction is aligned in a direction orthogonal to the axial direction of the FRP cylinder 20 in a tubular shape and thermosetting it. In the example of FIG. 3, the 90 ° layer 21O is drawn so as to be formed by one layer, but this is for convenience of drawing. That is, the number of layers of the 90 ° layer 21O (the number of 90 ° prepregs used to form the 90 ° layer 21O and the number of plies) has a degree of freedom, and various design changes are possible.

The gap in the inner region 32I of the serration portion 32 of the end joint 30 is filled with the 0 ° layer 21I. For example, in FIG. 3, the outer layer side of the 0 ° layer 21I over two layers shows the 0 ° layer 21I in the free state. When the serration portion 32 is press-fitted into the 0 ° layer 21I, a part of the 0 ° layer 21I (above the virtual line drawn by the alternate long and short dash line on the serration portion 32) is extruded, and the inner region 32I of the serration portion 32 Fill the valley bottom and its vicinity. That is, the inner region 32I of the serration portion 32 does not have to be entirely press-fitted into the 0 ° layer 21I in the radial direction, and a part of the radial direction may be press-fitted into the 0 ° layer 21I. Then, the non-press-fitted portion (including the valley bottom portion) of the inner region 32I of the serration portion 32 may be filled with the 0 ° layer 21I extruded by the press-fitted portion of the inner region 32I of the serration portion 32.

As described above, in the first embodiment, the serration portion 32 has an inner region 32I including the valley bottom portion of the serration portion 32 and an outer region 32O including the peak portion of the serration portion 32. Further, in the FRP cylinder 20, the inner region 32I of the serration portion 32 is press-fitted, and the 0 ° layer 21I having the fiber direction parallel to the axial direction of the FRP cylinder 20 and the outer region 32O of the serration portion 32 are press-fitted. It has a 90 ° layer 21O having a fiber direction orthogonal to the axial direction of the FRP cylinder 20. Further, the gap of the inner region 32I of the serration portion 32 of the end joint 30 is filled with the 0 ° layer 21I.

As a result, it is possible to prevent damage to the FRP cylinder 20 and improve the bonding strength between the FRP cylinder 20 and the end joint (joint member) 30. That is, in order to reduce the press-fitting load of the FRP cylinder 20 and the end joint 30 and prevent the inner layer side of the FRP cylinder 20 from peeling off, the inside (inner layer side) of the layer in which the serrations are bitten in the conventional product. A 0 ° layer is provided.

Since the 0 ° layer 21I has a fiber layer parallel to the extending direction of the serration portion 32, it is easy to cut when the serration portion 32 is press-fitted. Further, since the 0 ° layer 21I extruded by the notch fills the valley bottom of the inner region 32I of the serration portion 32 and its vicinity, it can be joined without damaging the FRP cylinder 20, and the FRP cylinder 20 during torque transmission can be joined. It is possible to prevent peeling of the innermost layer. Further, since the 90 ° layer 21O is press-fitted (bitten) only by the outer region 32O of the serration portion 32, the bonding strength with the end joint 30 is improved while preventing damage to the FRP cylinder 20. Can be made to.

FIG. 4 shows an example of the relationship between the height H of the serration portion 32, the biting height h1 of the 0 ° layer 21I with respect to the inner region 32I, and the biting height h2 of the 90 ° layer 21O with respect to the outer region 32O. It is a conceptual diagram.

In FIG. 4, the height H of the serration portion 32 and the biting height h1 of the 0 ° layer 21I with respect to the inner region 32I preferably satisfy 0.25 <h1 / H <0.50. By satisfying this condition, it is possible to prevent damage to the FRP cylinder 20 and improve the bonding strength between the FRP cylinder 20 and the end joint 30. If it falls below the lower limit of the above conditions, it becomes difficult for the 0 ° layer 21I to sufficiently fill the gap in the inner region 32I of the serration portion 32 of the end joint 30. If the upper limit of the above conditions is exceeded, it becomes difficult to press-fit the end joint 30 into the FRP cylinder 20, and the 0 ° layer 21I of the FRP cylinder 20 is peeled off.

In FIG. 4, the height H of the serration portion 32 and the biting height h2 of the 90 ° layer 21O with respect to the outer region 32O preferably satisfy 0.05 <h2 / H <0.25. By satisfying this condition, it is possible to prevent damage to the FRP cylinder 20 and improve the bonding strength between the FRP cylinder 20 and the end joint 30. If it falls below the lower limit of the above conditions, the amount of the 90 ° layer 21O biting into the outer region 32O becomes insufficient, and the end joint 30 tends to come off from the FRP cylinder 20 (the press-fitting of both tends to be released). If the upper limit of the above conditions is exceeded, it becomes difficult to press-fit the end joint 30 into the FRP cylinder 20.

Here, specific numerical values of the height H of the serration portion 32, the bite height h1 of the 0 ° layer 21I with respect to the inner region 32I, and the bite height h2 of the 90 ° layer 21O with respect to the outer region 32O. Disclosure is withheld, but these parameters are set to be related to each other to the extent that the above conditions are satisfied. For example, depending on the application of the FRP drive shaft 10, the height H1 and h2 increase as the height H increases, and the heights h1 and h2 decrease as the height H decreases. ..

<< Second Embodiment >>
FIG. 5 is a view of the joint portion between the FRP cylinder 20 and the end joint 30 viewed from the axial direction in the FRP drive shaft 10 according to the second embodiment.

As shown in FIG. 5, the gap of the inner region 32I of the serration portion 32 of the end joint 30 is filled with the 0 ° layer 21I and the adhesive 40. More specifically, the adhesive 40 fills the valley bottom of the gap in the inner region 32I of the serration portion 32 of the end joint 30, and the 0 ° layer 21I is the inner region of the serration portion 32 of the end joint 30. The part of the gap of 32I excluding the valley bottom is filled.

In the FRP drive shaft 10 according to the first embodiment, the gap of the inner region 32I of the serration portion 32 of the end joint 30 is filled with the 0 ° layer 21I. However, for example, when it is below the lower limit of 0.25 <h1 / H <0.50 described above, the gap of the inner region 32I of the serration portion 32 of the end joint 30 is sufficiently filled with the 0 ° layer 21I. It becomes difficult (the gap becomes large).

In the FRP drive shaft 10 according to the second embodiment, even in the above case, the valley bottom of the gap in the inner region 32I of the serration portion 32 of the end joint 30 is filled with the adhesive 40. The 0 ° layer 21I and the adhesive 40 work together to sufficiently fill the gap in the inner region 32I of the serration portion 32 of the end joint 30 (the gap portion can be made as small as possible).

When the FRP drive shaft 10 according to the second embodiment is manufactured, the end joint 30 is previously adhered to the valley bottom of the gap in the inner region 32I of the serration portion 32 of the end joint 30 before being press-fitted into the FRP cylinder 20. The agent 40 is applied. After that, when the end joint 30 is press-fitted into the FRP cylinder 20, the gap in the inner region 32I of the serration portion 32 of the end joint 30 is filled with the 0 ° layer 21I and the adhesive 40.

In the above embodiment, a case where a 90 ° layer 21O having a fiber direction orthogonal to the axial direction of the FRP cylinder 20 is used as the angle layer has been illustrated and described. However, the angular layer may have a fiber direction that diagonally intersects the axial direction of the FRP cylinder 20. Among them, by forming the angular layer from a layer having a fiber direction orthogonal to the axial direction of the FRP cylinder 20 of 30 to 150 °, the bonding strength (biting strength) with the outer region 32O including the peak portion of the serration portion 32 is formed. ) Can be secured to a certain extent. For example, as the angle layer, a bias layer that obliquely intersects the axial direction of the FRP cylinder 20 at ± 45 ° may be used.

The FRP drive shaft (FRP composite molded product) 10 of the present invention can be applied to, for example, an automobile propeller shaft and drive shaft, a robot arm, and a torque transmission shaft used in various other industries.

10 FRP drive shaft (FRP composite molded product)
20 FRP cylinder 21 Inner peripheral surface 21I 0 ° layer 21O 90 ° layer (angle layer)
22 Outer peripheral surface 30 End joint (joint member)
31 Rod part 32 Serration part 32I Inner area (inner diameter area)
32O outer area (outer diameter area)
40 adhesive

Claims (7)

An FRP cylinder with multiple FRP layers and
A joint member having a serration portion press-fitted into the inner peripheral surface of the FRP cylinder, and
Have,
The serration portion has an inner region including a valley bottom portion of the serration portion and an outer region including a mountaintop portion of the serration portion.
In the FRP cylinder, the inner region of the serration portion is press-fitted and the 0 ° layer having a fiber direction parallel to the axial direction of the FRP cylinder and the outer region of the serration portion are press-fitted and the FRP cylinder is press-fitted. With an angular layer having fiber directions that are oblique or orthogonal to the axial direction of
FRP composite molded product characterized by this. The gap in the inner region of the serration portion is filled with the 0 ° layer.
The FRP composite molded product according to claim 1, characterized in that. The gap in the inner region of the serration portion is filled with the 0 ° layer and an adhesive.
The FRP composite molded product according to claim 1, characterized in that. The adhesive fills the valley bottom of the gap in the inner region.
The 0 ° layer fills the portion of the gap in the inner region excluding the valley bottom.
The FRP composite molded product according to claim 3, characterized in that. When the height of the serration portion is defined as H and the biting height of the 0 ° layer with respect to the inner region is defined as h1, 0.25 <h1 / H <0.50 is satisfied.
The FRP composite molded product according to any one of claims 1 to 4, characterized in that. When the height of the serration portion is defined as H and the biting height of the angular layer with respect to the outer region is defined as h2, 0.05 <h2 / H <0.25 is satisfied.
The FRP composite molded product according to any one of claims 1 to 5, characterized in that. The angular layer is composed of a 30-150 ° layer having a fiber direction orthogonal to the axial direction of the FRP cylinder.
The FRP composite molded product according to any one of claims 1 to 6, characterized in that.

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