JP2011190931A - Propeller shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply reduce radiation noises caused by film vibration without using a special material by controlling a primary resonant frequency of a film, a secondary resonant frequency of the film in a propeller shaft used for an automobile and made from fiber reinforced plastics (FRP). <P>SOLUTION: The propeller shaft includes an FRP cylindrical body having a body cylindrical section 11 containing reinforced fiber layers and extending in a cylinder axis direction, and projection members which are a nodal-point position 15 of the primary film resonance and a nodal-point position 16 of the secondary resonance on the cylindrical body and are brought into contact with the outside or the inside of the FRP cylindrical body to be arranged between the reinforced layers and are made from reinforced layers 14 wound in a peripheral direction with a reinforced fiber, FRP, or a resin rigid body. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a propeller shaft made of fiber reinforced plastic (hereinafter referred to as FRP) used as a driving force transmission shaft of an automobile or the like.

  In the field of the automobile industry, attempts have been made to substitute various parts with FRP materials in order to reduce vehicle weight and reduce fuel consumption. In the case of FRP propeller shafts (also called propulsion shafts) among the various components, torque transmission for transmitting engine torque to the wheels by connecting the drive shaft and driven shaft to both ends of the FRP cylinder It has a structure in which joints are joined.

  In the propeller shaft, it is necessary to prevent the propeller shaft from a resonance phenomenon with respect to each vibration mode that is vibrated by rotation of a vibration generation source such as an engine or the propeller shaft itself during torque transmission. As the vibration mode of the propeller shaft, bending vibration and membrane vibration can be considered. The bending primary resonance frequency is determined by the cross-sectional secondary moment, longitudinal elastic modulus, specific gravity, and length of the cylindrical body. Therefore, in a steel propeller shaft, the bending primary resonance frequency is divided by dividing the length. However, in the propeller shaft using the FRP cylinder, the primary resonance frequency of the bending is used by effectively increasing the elastic modulus in the axial direction of the FRP cylinder. It is possible to avoid entering the vibration range in the region.

  The resonance frequency of the propeller shaft is calculated using the specific elastic modulus (elastic modulus / specific gravity), the length, and the like as parameters, and increases in proportion to the specific elastic modulus. The specific elastic modulus of CFRP is about 2.5 times the steel ratio. As a result, in the case of a steel propeller shaft, it cannot be established unless the cylinder length is shortened with a split structure, but with a CFRP propeller shaft, If it exists, the possibility of 1 piece 2 joint-izing by one cylinder arises, and the further weight reduction can be achieved.

  However, in the case where the FRP cylinder is used for the propeller shaft, the elastic modulus in the axial direction is made as high as possible in order to avoid the resonance frequency of the bending primary vibration from entering the vibration range in the use range as described above. Is effective, but as a result of the fate of FRP, which is an anisotropic material, the elastic modulus in the circumferential direction inevitably decreases significantly. In addition, when the length of the cylinder is increased by using one piece and two joints, the membrane primary resonance frequency and membrane secondary resonance frequency due to membrane vibration of the propeller shaft also become smaller and enter the vibration range in the use range of the automobile. As a result, resonance of the propeller shaft itself occurs while the vehicle is running, and unpleasant noise is generated.

  Therefore, in Patent Document 1, in order to improve the damping performance in the membrane primary resonance, the inside of the FRP cylinder at the center in the longitudinal direction which becomes the antinode of the vibration mode of the membrane primary resonance of the FRP cylinder is made of polyurethane or the like. Techniques for filling the foam to be produced have been proposed.

  However, the technique according to Patent Document 1 does not essentially solve the problem of shifting the primary and secondary resonance frequencies of the propeller shaft, so that not only the noise due to resonance remains but also the foam inside the FRP cylinder. Therefore, processing costs and material costs are increased.

Japanese Patent No. 3183428

  The present invention has been made in view of the above problems, and in a FRP propeller shaft used in an automobile or the like, controls a membrane primary resonance frequency and a membrane secondary resonance frequency and lowers a transfer function gain (sound pressure level). The object is to easily reduce the radiated sound accompanying the membrane vibration without using a special material or the like.

  In order to solve this problem, the present invention has the following configuration. That is, an FRP cylinder having a body cylinder portion including a reinforcing fiber layer and extending in the cylinder axis direction, a node position of the membrane primary resonance and a node position of the membrane secondary resonance in the cylinder, and the FRP cylinder A propeller shaft comprising a reinforcing layer formed by circumferential winding of reinforcing fibers, or a protruding member made of FRP or a rigid body made of resin, arranged in contact with the outside or inside of the body or between layers of the reinforcing fibers It is.

  According to the present invention, since the node positions of the membrane primary and membrane secondary resonances of the FRP cylinder are reinforced by the reinforcing layer and the protruding member, both the membrane 1 resonance frequency and the membrane secondary resonance frequency are used in the automobile. The transfer function gain (sound pressure level) can be reduced by suppressing the deformation of the FRP cylinders. As a result, it is possible to reduce the radiation volume caused by the membrane vibration generated when the propeller shaft rotates.

FIG. 3 is an axial sectional view showing a propeller shaft in which an outer reinforcing layer is disposed at a node position of resonance of the membrane primary and membrane secondary in the membrane vibration mode of the FRP cylinder, which is an embodiment of the present invention. It is an axial sectional view showing a propeller shaft in which an inner reinforcing layer is arranged at a node position of resonance of the membrane primary and membrane secondary in the membrane vibration mode of the FRP cylinder, which is an embodiment of the present invention. It is an axial sectional view showing a propeller shaft in which an intermediate reinforcing layer is arranged at a node position of resonance of the membrane primary and membrane secondary in the membrane vibration mode of the FRP cylinder, which is an embodiment of the present invention. FIG. 3 is an axial cross-sectional view showing a propeller shaft in which a protruding member is arranged on the inner surface of a cylinder at a resonance node position of the membrane primary and membrane secondary resonance in the membrane vibration mode of the FRP cylinder according to an embodiment of the present invention. . It is a perspective view which shows the column-shaped projection member used by one Embodiment of this invention. It is a perspective view which shows the cross-shaped projection member used by one Embodiment of this invention. It is an axial sectional view showing a conventional FRP propeller shaft. It is the schematic which shows a mode that the film mode resonance frequency of a propeller shaft is measured.

  The present invention will be described in more detail with reference to the drawings. 1 to 4 are axial sectional views of a propeller shaft according to the present invention, respectively, and FIG. 7 is an axial sectional view of a conventional FRP propeller shaft. 1-4 and FIG. 7, the main body cylinder parts 11, 21, 31, 41, 71 include a reinforcing fiber layer and extend in the cylinder axis direction to form an FRP cylinder, The torque transmission joints 17, 27, 37, 47 and 75 are joined. The reinforcing fiber layer constituting the main body cylinder portion is preferably a spiral wound layer of reinforcing fibers in order to make the torsional strength, the bending primary resonance frequency, etc. suitable for the propeller shaft. The winding angle of the spiral winding is usually within a range of ± 10 to ± 45 degrees with respect to the cylinder axis direction. The FRP cylinder includes circumferential winding layers 12, 22, 32, 42, and 72 of reinforcing fibers on the inner peripheral surface of the cylindrical axial ends of the main body cylinder parts 11, 21, 31, 41, and 71. It is good to be configured. When a torque transmission shaft is press-fitted and joined to the circumferentially wound layer of the reinforcing fiber, the corresponding portion of the cylindrical body is reinforced in the circumferential direction, so that deformation and damage to the spirally wound layer can be prevented, and suitable torque transmission is obtained. be able to. In the present invention, the circumferential direction usually means a direction within a range of ± 80 to 90 degrees with respect to the cylinder axis direction.

  Here, in FIG. 1, the reinforcing layer 14 by the circumferential winding of the reinforcing fiber is in contact with the outside of the FRP cylinder at the node position 15 of the membrane primary resonance and the node position 16 of the membrane secondary resonance in the cylinder. In FIG. 2, the reinforcing layer formed by circumferential winding of reinforcing fibers is in contact with the inner side of the FRP cylinder at the node position 25 of the membrane primary resonance and the node position 26 of the membrane secondary resonance in the cylinder. 24 is arranged. In FIG. 3, the fiber primary resonance node position 35 and the film secondary resonance node position 36 in the cylindrical body are interposed in the middle (interlayer) of the spiral wound layer of the reinforcing fiber constituting the FRP cylinder, and the reinforcing fiber. A reinforcing layer 34 is disposed by circumferential winding.

  In FIG. 4, a protruding member 44 made of a rigid body is disposed in contact with the inner side of the FRP cylinder at the node position 45 of the film primary resonance and the node position 46 of the film secondary resonance in the cylinder. The rigid body is made of FRP or resin to reduce the weight of the propeller shaft. In FIG. 4, the protruding member is disposed in contact with the inside of the FRP cylinder, but may be disposed in contact with the outside of the FRP cylinder in the same form as in FIG. 3 may be arranged in the middle of the spiral wound layer of reinforcing fibers constituting the FRP cylinder in the same form as in the case of No. 3. The protruding member refers to a member that is arranged so as to protrude from the reinforcing fiber layer constituting the FRP cylinder to the outside or the inside of the cylinder.

  The nodal position of the membrane primary resonance and the nodal position of the membrane secondary resonance in the FRP cylinder are affected by the length of the cylinder, the shape of the cylinder (the fluctuation of the outer diameter and inner diameter in the axial direction, etc.), etc. However, the position from the cylinder end face can be specified by using FEM calculation with a computer. For example, if both the inner diameter and the outer diameter are a cylindrical body that is uniform in the axial direction, the primary node position of the membrane is the axial center of the cylindrical body, that is, the entire length of the cylindrical body from the end of the cylindrical body. The position of the second layer of the membrane is 1/4 and 3/4 in the axial direction, that is, 1/4 of the total length of the cylinder in the axial direction from the end of the cylinder. It becomes the position of the length and the position of the length of 3/4. In the case of a cylindrical body having a partially large outer diameter, or when the outer diameter is tapered in the axial direction, the node position of the membrane secondary resonance deviates from the above position, but it can be accurately calculated using FEM calculation. .

  The FRP cylinder is provided with a reinforcing layer and a protruding member having a thickness at the node positions 15, 25, 35, 45 of the membrane primary resonance and the node positions 16, 26, 36, 46 of the membrane secondary resonance. Therefore, the resonance frequency of the membrane mode can be increased so as to deviate from the vibration range in the use range. Furthermore, since the reinforcing layer is a circumferential winding of reinforcing fibers and the protruding member is made of FRP or a resin rigid body, the FRP cylinder can be prevented from being crushed and deformed.

  The reinforcing layers 14, 24, and 34 and the protruding member 44 preferably have an axial width of 3 to 90 mm and a thickness of 1 to 5 mm. If the width is smaller than 3 mm, the allowance for deviation from the node position of the membrane primary and membrane secondary resonances is small, and the deformation may be crushed by a slight deviation, so that the deformation suppressing effect is reduced. On the other hand, when the width is larger than 90 mm, the amount of reinforcing fiber input is increased, and the cost performance for suppressing crushing deformation is deteriorated. On the other hand, if the thickness is less than 1 mm, the improvement in the resonance frequency of the membrane mode is small, and if it is more than 5 mm, the resonance frequency becomes higher than necessary and the amount of reinforcing fibers input increases, which also deteriorates the cost performance.

  In the present invention, when the protruding member is used, if the inner diameter and outer diameter of the FRP cylinder are finished with high accuracy, if only the outer peripheral surface or inner peripheral surface of the protruding member is machined, it can be easily inserted and fixed by press-fitting or bonding. can do. If the outer diameter of the end of the cylinder is thicker than the outer diameter of the other part, the protruding member cannot be inserted and fixed from the end by press-fitting or bonding. That's fine. Further, in the present invention, when the projecting member is arranged inside the FRP cylinder, the cylindrical projecting member 51 as shown in FIG. 5 or shown in FIG. 6 is used instead of the cylindrical body like the projecting member 44 in FIG. Such cross-shaped projecting members 61 may be used, and the ends of these projecting members may be arranged so as to contact the inner surface of the FRP cylinder. Note that the columnar protruding member 51 and the cross-shaped protruding member 61 preferably have an axial width of 3 to 90 mm.

  In the present invention, carbon fibers, glass fibers, aramid fibers, boron fibers, ceramic fibers and the like are used as the reinforcing fibers, and among these, the use of carbon fibers is preferable in view of the critical rotational speed. When carbon fibers are used as the reinforcing fibers, the reinforcing fibers other than the carbon fibers may be 40% by mass or less based on the total mass of the reinforcing fibers in consideration of the torsional strength and the dangerous rotational speed necessary for the propeller shaft. preferable.

  In addition, the resin impregnated into the reinforcing fiber to form FRP, so-called matrix resin includes epoxy resin, unsaturated polyester resin, phenol resin, vinyl ester resin and other thermosetting resins, polyvinyl acetate resin, polycarbonate resin, polyacetal. Resin, polyphenylene oxide resin, polyphenylene sulfide resin, polyarylate resin, polyester resin, polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyaramid resin, poly Thermoplastic resins such as benzimidazole resin, polyethylene resin, polypropylene resin, and cellulose acetate resin are preferably used. Among these, good workability and after molding Preferably consideration and the thermosetting resin that excellent mechanical properties, among others, epoxy resin is particularly preferably used.

  Next, a method suitable for producing the propeller shaft of the present invention will be described.

  First, the FRP cylinder is drawn by applying filament fibers (hereinafter referred to as FW) method, tape winding (hereinafter referred to as TW) method, reinforcing fibers impregnated with matrix resin, applying a predetermined tension and winding them around a mandrel. Shape.

  When forming a reinforcing layer, it winds in the circumferential direction at a position to be a node of membrane resonance, and when forming a circumferential winding layer at the end of the main body cylindrical portion in the cylindrical axis direction, the cylindrical shaft of the main body cylindrical portion The main body tube portion may be wound continuously at a position where it should become a directional end, and the main body cylinder portion is continuously and integrally wound by spiral winding at a winding angle calculated so as to obtain a desired torsional strength and bending primary resonance frequency. Can be shaped. The circumferential winding of the reinforcing layer can be accurately arranged by using numerical control of the FW device.

  In the case where a thermosetting resin is used as the matrix resin, a molded body is obtained by putting it into a curing furnace after curing and curing it under predetermined curing conditions. Thereafter, the mandrel is pulled out from the molded body using a decentering machine or the like and cut into a predetermined length using a cutting machine or the like to obtain an FRP cylinder.

  When reinforcing with the protruding member, the protruding member is inserted into the inside or outside of the FRP cylinder from the end of the FRP cylinder obtained as described above. The insertion may be press-fitted without using an adhesive or the like, or may be inserted and bonded using an adhesive or the like.

  Next, the propeller shaft of the present invention will be described more specifically using examples. In this example, the transfer function gain (sound pressure level), the membrane mode resonance frequency, and the noise were evaluated as follows.

[Transfer function gain (sound pressure level) and membrane mode resonance frequency]
The transfer function gain (sound pressure level) and the membrane mode resonance frequency are measured by an impulse excitation test. FIG. 8 is a schematic view showing how the transfer function gain (sound pressure level) and the membrane mode resonance frequency of the propeller shaft are measured. An acceleration sensor 81 is attached to the center of the FRP cylinder 80 to be measured. In this state, an impulse hammer 83 incorporating a force sensor 82 is vibrated, and the outputs of the force sensor 82 and the acceleration sensor 81 are input to the input channel module 84 (for example, AD-3651 manufactured by A & D Corporation). The transfer function gain (sound pressure level) and the resonance frequency are obtained by obtaining and displaying the transfer function using the FFT dedicated software (for example, WCAMSA manufactured by A & D Co., Ltd.). Obtainable.

[Volume of radiated sound]
The propeller shaft to be measured is mounted on a real car (sedan car), and the propeller shaft is rotated via the engine output. Install a microphone and measure.

Example 1
An FRP cylinder was formed by the FW method. That is, three carbon fiber bundles (average single yarn diameter: 7 μm, number of single yarns: 24,000, tensile strength 4900 MPa, tensile elastic modulus: 230 GPa) are aligned, and this is bisphenol A containing a curing agent and a curing accelerator. While impregnating a mold epoxy resin as a matrix resin, a mandrel having an outer diameter of 80 mm and a length of 1,300 mm is first wound around an end portion of 100 mm at eight layers at an angle of ± 82 ° with respect to the axial direction. After forming a partial layer of .5 mm, move to the other end to form a partial layer in the same manner, and then wrap five layers at an angle of ± 12 ° with respect to the axial direction over the entire length of the mandrel. The main layer is formed, and then wound around the entire length of the mandrel at −83 ° with respect to the axial direction. Further, the width is centered on the membrane primary node position 15 and the membrane secondary node position 16. Over 0 mm, to form a reinforcing layer having a thickness of 2.5mm by winding eight layers at an angle of ± 83 °. It should be noted that FEM calculation is performed in advance on the obtained FRP cylinder, and the primary node position of the film is in the axial center of the cylinder and the secondary node position of the film is 1/4 part in the axial direction of the cylinder. And 3/4 part, it has been specified that they are 30 mm apart from each other toward the center in the axial direction.

  Next, the epoxy resin is cured by heating at 180 ° C. for 6 hours while rotating the mandrel, and after pulling out the mandrel, each end 50 mm is cut and removed, the outer diameter is 85 mm, the inner diameter is 80 mm, An FRP cylinder having a length of 1,200 mm was obtained.

  Thereafter, a yoke 17 was press-fitted and joined to each end of the FRP cylinder to obtain an FRP propeller shaft as shown in FIG.

  When the membrane mode resonance frequency of the obtained propeller shaft was measured, the membrane primary resonance frequency was 1500 Hz and the membrane secondary resonance frequency was 1550 Hz, which was 25% higher than the comparative example described later. The transfer function gain (sound pressure level) was 105 dB in the 0.8 region (hereinafter referred to as the skirt region) of the membrane primary resonance frequency (1190 Hz) of the comparative example described later, which was 15% lower than the comparative example. With respect to this propeller shaft, the volume of the radiated sound was measured and found to be about 80 dB, which was almost the same as that of a 2-piece 3-joint steel propeller shaft.

(Example 2)
An FRP cylinder having an outer diameter of 85 mm, an inner diameter of 80 mm, and a length of 1,200 mm was obtained in the same manner as in Example 1 except that the reinforcing layer was not formed.

  Thereafter, an adhesive is applied to the outer peripheral surface of the cylindrical body 44 having a width of 60 mm, an outer diameter of 80 mm, and a thickness of 2.5 mm prepared by FRP, so that the primary node position (axial center) 45 of the membrane and the secondary node of the membrane are applied. The cylindrical body 44 was inserted and fixed so that the center of the position was centered on the position 46 (330 mm portion and 870 mm portion in the axial direction from one end face of the FRP). Thereafter, a yoke 47 was press-fitted and joined to each end of the FRP cylinder to obtain an FRP propeller shaft as shown in FIG.

  When the membrane mode resonance frequency of the obtained propeller shaft was measured, the membrane primary resonance frequency was 1680 Hz, and the membrane secondary resonance frequency was 1720 Hz, which was 40% higher than the comparative example described later and higher than that of Example 1. As a result. With respect to this propeller shaft, the volume of the radiated sound was measured and found to be about 80 dB, which was almost the same as that of a 2-piece 3-joint steel propeller shaft.

(Comparative example)
An FRP cylinder having an outer diameter of 85 mm, an inner diameter of 80 mm, and a length of 1,200 mm was obtained in the same manner as in Example 1 except that the reinforcing layer was not formed. A yoke 75 was press-fitted and joined to each end of the obtained FRP cylinder to obtain an FRP propeller shaft as shown in FIG.

  When the membrane mode resonance frequency of the obtained propeller shaft was measured, the membrane primary resonance frequency was 1190 Hz and the membrane secondary resonance frequency was 1280 Hz. The transfer function gain (sound pressure level) in the base region of the membrane primary resonance frequency was 125 dB. With respect to this propeller shaft, the volume of the radiated sound was measured and found to be about 90 dB, which was about 10 dB worse than about 80 dB of the 2-piece 3-joint steel propeller shaft.

  The propeller shaft according to the present invention can be applied to any propeller shaft, and is particularly suitable when applied to a vehicle propeller shaft.

11, 21, 31, 41, 71: Main body cylindrical portions 12, 22, 32, 42, 72: Circumferential winding layers 14, 24, 34: Reinforcement layers 15, 25, 35, 45: Node positions of the membrane primary resonance 16, 26, 36, 46: Nodal positions 17, 27, 37, 47, 75 of membrane secondary resonance: Torque transmission joint 44: Cylindrical protruding member 51: Columnar protruding member 61: Cross-shaped protruding member 80: FRP cylinder Body 81: Acceleration sensor 82: Force sensor 83: Impulse hammer 84: Input channel module 85: Host computer

Claims (6)

An FRP cylinder having a main body cylinder portion including a reinforcing fiber layer and extending in the cylinder axis direction; a nodal position of a membrane primary resonance and an nodal position of a membrane secondary resonance in the cylinder; A propeller shaft comprising a reinforcing layer formed by circumferential winding of reinforcing fibers, or a projecting member made of FRP or a resin rigid body, arranged in contact with the outside or inside or between layers of the reinforcing fibers. . The propeller shaft according to claim 1, wherein the reinforcing layer and the protruding member have a width of 3 to 90 mm and a thickness of 1 to 5 mm. 2. The propeller shaft according to claim 1, wherein the protruding member has a cylindrical shape with a width of 3 to 90 mm or a cross shape with a width of 3 to 90 mm. The reinforcing fiber layer constituting the main body cylinder is a spiral wound layer of reinforcing fibers, and the FRP cylinder includes a circumferential winding layer of reinforcing fibers on the inner peripheral surface of the end of the main body cylinder in the cylinder axial direction. The propeller shaft according to any one of claims 1 to 3. The propeller shaft according to any one of claims 1 to 4, wherein the circumferential direction is a direction within a range of ± 80 to 90 degrees with respect to the cylinder axis direction. The propeller shaft according to any one of claims 1 to 4, wherein torque transmission joints are joined to both ends.

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