JP2002147532A - Propeller shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a dynamic damper on a predetermined position in a pipe body and maintain safety, heat resistance, and durability without an adhesive, a fixing member or an adhesion process. SOLUTION: The dynamic damper 10 comprising a cylindrical mass member 11 and an elastic body 12 provided in such a manner of covering an outer peripheral surface of the mass member 11 is used. An outer diameter R2 of the elastic body 12 is larger than an inner diameter R1 of the pipe body 2. While elastically deforming the elastic body 12 by compression, the dynamic damper 10 is fixed on an inner peripheral side of the pipe body 2 in order to constitute this propeller shaft 1. The compression of the elastic body 12 is set so that abrasion resistance at a contact surface of elastic parts 12a and 12b and the inner peripheral surface of the pipe body 2 is larger than force of the dynamic damper 10 to come out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propeller shaft of a motor vehicle, and more particularly to a propeller shaft having improved dynamic damper material and mounting structure.

[0002]

2. Description of the Related Art A propeller shaft is a propulsion shaft for transmitting the driving force of an automobile engine from a transmission to a reduction gear. Generally, a dynamic damper for suppressing the vibration of the propeller shaft is installed inside a tubular body. It is composed. This dynamic damper mainly includes a mass member (mass portion) and an elastic body (rubber portion).

[0003] When operations such as starting and stopping of an automobile are repeatedly performed, mainly the longitudinal direction of the vehicle (ie, the axial direction of the pipe).
Acceleration occurs. When this acceleration is applied to the mass member, a force corresponding to the acceleration is applied to the entire dynamic damper. Therefore, when the dynamic damper is not sufficiently fixed to the pipe, the dynamic damper starts to slide due to the acceleration, and moves from a predetermined position (ie, a position where the dynamic damper works optimally in the pipe). There is a problem that the effect of the dynamic damper is reduced.

Considering the influence of such acceleration,
For example, Japanese Unexamined Patent Application Publication No. 3-223543 and Japanese Utility Model Application Laid-Open No.
It is necessary to configure a dynamic damper as shown in Japanese Patent No. 122843 so that the dynamic damper does not move from a predetermined position of the pipe.

[0005] Japanese Utility Model Laid-Open No. 4-122842 discloses an outer pipe (outer cylinder; an inner cylinder for fixing an inner weight at a predetermined position) having a cylindrical outer diameter set to be larger than the inner diameter of the propeller shaft body and having a slit formed in an axial direction. Fixing member)
And a dynamic damper comprising: an inner weight (mass portion) disposed at the axis of the outer pipe; and a mount rubber interposed between the outer pipe and the inner weight to elastically connect the two. A configuration in which the dynamic damper is inserted into the main body of the propeller shaft (hereinafter, referred to as a press-contact type configuration) is described. The outer peripheral surface of the outer pipe is pressed against the inner peripheral surface of the propeller shaft main body by the elastic force of the mount rubber.

JP-A-3-223543 discloses a main vibration system in which a propeller shaft itself is a mass and a rubber-based elastic body is a spring, and an auxiliary vibration system in which a mass member provided on the propeller shaft is a mass and an auxiliary elastic body is a spring. A structure in which a solid (or sleeve-shaped) mass member is concentrically attached to the inside of a cylindrical tube via an auxiliary elastic body (hereinafter referred to as an adhesive) Mold configuration). The auxiliary elastic body is provided to the tube by, for example, bonding (vulcanization bonding, adhesive).

[0007]

However, the press-contact type structure shown in Japanese Utility Model Application Laid-Open No. 4-122842 requires a fixing member such as an outer pipe. The mold configuration requires an adhesive and a bonding step, and thus has a problem that the manufacturing cost increases.

As a method of reducing the manufacturing cost in the above-mentioned bonding type structure, a method of forming a dynamic damper in a tube without using an adhesive or through a bonding process can be considered. Since it is necessary to prevent the user from moving from a predetermined position, it has not been practically used in terms of safety.

Further, chloroprene rubber or natural rubber is used for the elastic body of the dynamic damper. However, due to the recent deterioration of the working environment of the dynamic damper (in a thermal environment exceeding 100 ° C.), the chloroprene rubber is used. Elastic bodies made of natural rubbers are not satisfactory in heat resistance and cause thermal degradation, which is not practical.

Therefore, there is a demand for the development of a propeller shaft that sufficiently secures the characteristics required of a dynamic damper and solves the above-mentioned problems.

The present invention has been made based on the above-mentioned problem, and it is an object of the present invention to provide an inexpensive and sufficiently safe propeller shaft using a dynamic damper comprising an elastic body having heat resistance.

[0012]

In order to solve the above-mentioned problems, the present invention comprises a tube and a dynamic damper, wherein the dynamic damper has a cylindrical or cylindrical mass member, and a dynamic damper. A propeller shaft including an elastic body provided so as to cover an outer peripheral surface thereof, wherein the dynamic damper is assembled in the tubular body such that an outer peripheral portion of the elastic body directly contacts an inner peripheral side of the tubular body. hand,
An outer diameter of the elastic body is formed larger than an inner diameter of the tubular body, and the dynamic damper is fixed to an inner circumferential side of the tubular body while compressing and elastically deforming the elastic body. Is that the frictional resistance at the contact surface between the elastic body and the inner peripheral surface of the tube is larger than the pull-out force of the dynamic damper (that is, the load when the elastic portion slides out of a predetermined position of the propeller shaft and moves). It is characterized by having been set as follows.

In the propeller shaft of the present invention, a plurality (preferably three or more) of elastic portions may be provided on the outer peripheral side of the elastic body so as to radially protrude in the radial direction of the elastic body. .

The elastic material is composed of 100 parts by weight of ethylene / α-olefin / non-conjugated diene copolymer rubber, 0.1 to 10 parts by weight of sulfur, and 25 to 10 parts of carbon black.
The rubber composition preferably contains 0 parts by weight.

Further, the ethylene / α-olefin / non-conjugated diene copolymer rubber is ethylene, having 3 to 3 carbon atoms.
20 α-olefins and non-conjugated dienes, and ethylene / α-olefins having a molar ratio of 65/35 to
73/27, the intrinsic viscosity [η] measured in decalin at 135 ° C. was 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in a state where 50 phr of a paraffinic oil was oil-extended was 0.2. It is preferable that the non-conjugated diene is 5-ethylidene-2-norbornene.

Conventionally (the above-mentioned Japanese Utility Model Application Laid-Open No. 4-122842,
Japanese Unexamined Patent Publication No. Hei 3-223543 discloses a method of using an adhesive or a fixing member on the inner peripheral side of a tubular body for the purpose of preventing the dynamic damper from moving absolutely from a predetermined position in the tubular body in the axial direction. The dynamic damper is fixed after the process. However, in practice, it is not necessary to use an adhesive or a fixing member or go through a bonding step in order to achieve the above-mentioned object.

On the other hand, as described above, according to the present invention, when the dynamic damper is fixed in the pipe, the elastic body (and the elastic portion) of the dynamic damper is compressed and elastically deformed. For this reason, a reaction force is generated in the elastic body,
The frictional resistance between the elastic body and the inner peripheral surface of the tube increases.

When the load applied to the dynamic damper (mainly, the mass member) in the axial direction of the pipe becomes larger than the frictional resistance, the elastic body of the dynamic damper starts to slide from a predetermined position in the pipe. . The load required for the elastic body to start sliding, that is, the pull-out force, is due to acceleration generated by operations such as starting and stopping the vehicle.

The release force varies depending on the use conditions of the dynamic damper, but mainly varies depending on the mass member of the dynamic damper. That is, when the acceleration (maximum acceleration) in the axial direction of the tubular body is 15 G, a load equivalent to 15 times the mass of the mass member is applied to the dynamic damper. For example, when a dynamic damper using a mass member having a mass of 250 g is used and the acceleration applied to the dynamic damper is 15 G, a removal force of 3750 g (250 (g) × 15 (G)) is required.

In the present invention, the frictional resistance is set to be larger than the above-described pulling force. In addition, the frictional resistance is determined by the safety factor (for example, 2
May be set larger than the value obtained by multiplying the value.

The ethylene / α-olefin / non-conjugated diene rubber copolymer (main component; hereinafter referred to as EP) used for the elastic body
DM) can be produced, for example, by the method described in JP-B-59-14497, that is, using hydrogen as a molecular weight regulator in the presence of a Ziegler catalyst, ethylene, carbon atoms of 3 ~ 20 α-olefins and dienes can be obtained by copolymerization. The EPDM preferably has an iodine value in the range of 10 to 25.

In the above-mentioned carbon black, carbon black for rubber is used.
Furnace carbon black such as F, MAF, FEF, and GPF is used. The carbon black is EP
25 to 100 parts by weight, preferably 40 to 100 parts by weight, more preferably 50 to 80 parts by weight, based on 100 parts by weight of DM.

The α-olefin having 3 to 20 carbon atoms includes propylene, butene-1, hexene-1,
Pentene-1, 4-methylpentene-1, heptene-
1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, Eicosene-1 and the like, and these α-olefins can be used alone or in combination.

In the rubber composition, a vulcanization accelerator, which has been widely used in the production of a vulcanized rubber molded article comprising ethylene / propylene rubber, etc., in addition to the above-mentioned EPDM, sulfur and carbon black, is used. A compounding agent such as a softening agent may be used within a range not to impair the object of the present invention.

The rubber composition is formed into a desired shape by, for example, an extruder, a calender roll, a press or the like. 1-3 at 270 ° C
Vulcanize by heating for 0 minutes. In addition, at the time of the vulcanization, a mold may or may not be used.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a propeller shaft according to an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 2, the propeller shaft 1 of this embodiment is a three-joint type propeller shaft having joints 3 at both ends of a tubular body 2 and an intermediate bearing 4 at the center. Needless to say, the present invention can be applied to a two-joint type propeller shaft.

As shown in FIG. 1, a dynamic damper 10 is mounted in the tube 2. As shown in FIGS. 3A and 3B, the dynamic damper 10 covers a cylindrical mass member 11 made of metal (for example, a steel bar) and an outer peripheral surface of the mass member 11. And an elastic body 12 formed as described above. Elastic body 12
, Elastic portions 12a and 12b are formed to protrude at two positions in the axial direction of the mass member 11. Elastic part 12
a and 12b are radial in the radial direction of the elastic body 12 (FIG. 3).
A plurality (three in FIG. 3A) are formed at equal intervals so as to protrude in three directions in (A).

In this embodiment, the heat resistance (air heating aging test described later) of various rubber compositions using EPDM and chloroprene rubber was examined, and the above-mentioned dynamic damper was prepared using the rubber composition having excellent heat resistance. 10 was to be manufactured. As shown in FIG. 1, the outer diameter R2 of the elastic body 12 of the dynamic damper 10 is changed to the inner diameter R1 of the tube 2.
The elastic body 12 (especially the elastic portion 12) is set to be larger than that of the elastic body 12 without using an adhesive or a fixing member or through an adhesive process.
The dynamic damper 10 is built in a predetermined position in the tubular body 2 while compressing and elastically deforming a, 12b) so that the dynamic damper 10 does not slide and move from the predetermined position. By these, reduction of manufacturing cost, maintenance of characteristics such as heat resistance and vibration absorption for a long time, and securing of safety were studied.

Then, first, the heat resistance of the rubber composition was examined. As a main component, 100 parts by weight of EPDM, 1 part by weight of sulfur, and 50 parts by weight of carbon black are used, and as additives, 5 parts by weight of zinc white, 1 part by weight of stearic acid,
2 parts by weight of a vulcanization accelerator were added, and a rubber composition sample S1 was prepared by vulcanization molding. For comparison with the sample S1, a rubber composition sample S2 was prepared using chloroprene rubber instead of the EPDM.

The EPDM is composed of ethylene, propylene and a non-conjugated diene, and the molar ratio of ethylene to propylene (ethylene / propylene) is 70/30.
The intrinsic viscosity [η] measured in decalin at 135 ° C. is 3.9.
dl / g, the melt flow index at 230 ° C. in a state where the paraffinic oil was oil-extended at 50 phr was 0.3 g / 10 min, and the non-conjugated diene was 5-ethylidene-2-norbornene.

The samples S1 and S2 were subjected to an air heating aging test by the following method, and the test results are shown in Table 1 below. First, in accordance with JIS K 6257, dumbbell-shaped No. 3 test pieces were prepared from the samples S1 and S2, and the test pieces were heated at a temperature of 120 ° C.
Heating under an atmosphere of 70 hours after (normal oven method), hardness change △ Hs of each specimen (points), modulus change rate △ M _{100 (%),} tensile strength change rate (breaking strength) △ T _B (%), elongation rate of change △ _E B (%) was measured. In each of the above test pieces, those having a hardness change rate of +5 points or less were evaluated as good, and those exceeding +5 points were evaluated as poor.

[0033]

[Table 1] As shown in Table 1 above, it can be seen that the hardness change, modulus change rate, tensile strength change rate, and elongation change rate of the test piece of sample S1 are better than those of the test piece of sample S2. From this, EPD as in sample S1
It was confirmed that an elastic body having high heat resistance and high durability was obtained by using the rubber composition containing M.

Next, using the sample S1, the dynamic damper 10 shown in FIGS. 3A and 3B was manufactured. At that time, the outer diameter R2 of the elastic body 12 is 68.1.
5 mm. And this dynamic damper 10
4, the elastic body 12 was compressed and elastically deformed by applying a load as shown in FIG. 4, and the reaction characteristics due to the elastic deformation were examined.

In FIG. 4, reference numeral 21 denotes a substantially U-shaped jig. On the upper surface of the jig 21, there is formed a pressure contact surface 21a having a curvature similar to the inner peripheral surface of a general propeller shaft tube. The elastic portion 12a of the dynamic damper 10 with respect to the pressing surface 21a,
The front surface (outer peripheral surface; hereinafter, referred to as the front surface) of the front end 12b is brought into contact with the load (N) in the direction of the mark C in FIG.
To the elastic body 12 (mainly, the elastic portion 1).
2a, 12b) are compressed and elastically deformed as shown by the dotted line in FIG.

The amount of displacement L (mm) of the elastic body 12 when elastically deformed as described above is measured, and a reaction force generated by the elastic deformation (hereinafter referred to as a reaction force).
Was measured, and the results are shown in the reaction force characteristic diagram with respect to the displacement amount in FIG.

From the results shown in FIG. 5, the elastic parts 12a, 12a
It can be seen that the reaction force acting on the elastic body 12 increases in proportion to the displacement L when the b is elastically deformed (in proportion to a quadratic function). Since this reaction force is due to two of the six elastic portions of the elastic body 12, the reaction force that is three times the measured value shown in FIG. 5 causes the dynamic damper 10 to move inside the pipe 2 of the propeller shaft 1. The reaction force of the entire elastic body 12 generated when the elastic body 12 is fixed to each other (each elastic portion 12a, 12b of the elastic body 12)
The sum of the reaction forces).

Next, two kinds of pipes P1 (inner diameter 60.85 mm) and P2 whose inner diameters are smaller than the outer diameter of the elastic body 12 are shown.
The dynamic damper 10 was fixed to a predetermined position in each of the pipes P1 and P2 while compressing and elastically deforming the elastic body 12 using an inner diameter of 59.65 mm.

Here, the displacement L of the elastic body 12 when the dynamic damper 10 is fixed in each of the pipes P1 and P2 can be calculated by the following equation (1). In the following equation (1), R1 is the inner diameter of the pipes P1 and P2, and R2 is the outer diameter of the elastic body 12.

Displacement L = (R2−R1) / 2 (1) According to the above equation (1), the displacement L of the elastic body 12 in each of the pipes P1 and P2 is 3.65 mm. ,
It was 4.25 mm. From this, according to the characteristic diagram shown in FIG. 5, the reaction force of the elastic body 12 in the dynamic damper 10 built in the pipes P1 and P2 is 5
It can be read that they are 85N and 705N.

The mass member 11 of the dynamic damper 10 is moved at a speed of 50 mm / min in the axial direction of the pipes P1 and P2, and the loads required for the movement are measured. The results are shown in FIG. 6 (when the pipe P1 is used) and in FIG. 7 (when the pipe P2 is used), respectively, in the load characteristic diagram with respect to the movement amount (mm) of the mass member.

As shown in FIGS. 6 and 7, for a while after the mass member 11 started to move (region s1 in FIG. 6, and region s2 in FIG. 7), it was necessary to move the mass member 11. The load suddenly increases, and the load reaches a predetermined size (FIG. 6).
Immediately after reaching about 147N in FIG. 7 and about 167N in FIG. 7 (region t1 in FIG. 6 and region t2 in FIG. 7), the mass member 11 Has moved.

The reason is that for a while after the mass member 11 starts to move, the frictional resistance at the contact surface between the distal end surfaces of the elastic portions 12a and 12b and the inner peripheral surfaces of the pipes P1 and P2 is small. As the mass member 11 moves, the elastic members 12a and 12b move along with the elastic members 12a and 12b in a state where the distal end surfaces of the elastic members 12a and 12b do not move from the predetermined positions of the pipes P1 and P2.
It can be read that each has elastically deformed in the axial direction of the pipes P1 and P2.

The frictional resistance increases in proportion to the magnitude of the reaction force applied to the elastic body 12 (especially, each of the elastic portions 12a and 12b). From this, the reaction force decreases with the movement of the mass member 11, and immediately after the load applied to the mass member 11 reaches a predetermined magnitude, that is, the load applied to the mass member 11 becomes larger than the frictional resistance. Immediately after, the distal end surfaces of the elastic portions 12a and 12b
It can be read that the vehicle has started sliding from a predetermined position in P1 and P2.

As described above, the load applied to the mass member 11 immediately before the distal end surfaces of the elastic portions 12a and 12b start to slide corresponds to the pulling force of the dynamic damper 10. FIG. 8 is a characteristic showing the relationship between the pull-out force of the dynamic damper 10 in each of the pipes P1 and P2 and the reaction force of the elastic body 12 when the dynamic damper 10 is built in each of the pipes P1 and P2. FIG. As shown in FIG. 8, since the pull-out force increases with an increase in the reaction force, it can be read that the dynamic damper 10 becomes harder to fall out of the tubes P1 and P2 as the reaction force of the elastic body increases.

Therefore, as described above, the elastic body 12 of the dynamic damper 10 is fixed in the tubular body 2 while being elastically deformed and the reaction force is increased, so that the pull-out force of the dynamic damper 10 is set to be sufficiently large. be able to. Therefore, the dynamic damper 10 can be fixed at a predetermined position in the tubular body 2 without using an adhesive or a fixing member or through an adhesion process, and safety, heat resistance, and durability can be maintained.

Although the present invention has been described in detail with reference only to the specific examples described above, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention. It goes without saying that such variations and modifications belong to the scope of the claims.

For example, in order to increase the frictional resistance, the present embodiment employs a method of increasing the reaction force by the elastic deformation of the elastic body in the dynamic damper. May be increased. Further, the number of the elastic portions of the elastic body can be variously changed within a range in which the operation and effect as described above can be obtained.

[0049]

According to the propeller shaft according to the present invention, the dynamic damper is fixed at a predetermined position in the tube without using an adhesive or a fixing member or through a bonding step, so that the manufacturing cost can be reduced. Further, the dynamic damper in the tubular body does not move from a predetermined position even at a large acceleration (acceleration that may be caused by an operation of an automobile or an accident), and can secure safety. Furthermore, since a dynamic damper made of a rubber composition having heat resistance is used, characteristics such as heat resistance and vibration absorption required for the dynamic damper can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a propeller shaft according to an embodiment of the present invention.

FIG. 2 is an overall schematic view of the propeller shaft.

FIG. 3A is a front view of a dynamic damper assembled to the propeller shaft, and FIG.
It is an I line sectional view.

FIG. 4 is a schematic explanatory view showing a method of measuring a displacement amount and a reaction force in a dynamic damper.

FIG. 5 is a reaction force characteristic diagram with respect to a displacement amount of an elastic body in a dynamic damper.

FIG. 6 is a load characteristic diagram with respect to a moving amount in the pipe body P1.

FIG. 7 is a load characteristic diagram with respect to a moving amount in a pipe P2.

FIG. 8 is a characteristic diagram of a reaction force with respect to a pull-out force in a dynamic damper.

[Explanation of symbols]

 10 Dynamic damper 11 Mass member 12 Elastic body 12a, 12b Elastic part 21 Jig 21a Pressure contact surface

Claims (4)

[Claims] 1. A dynamic damper comprising a tubular body and a dynamic damper, wherein the dynamic damper comprises a cylindrical or cylindrical mass member, and an elastic body provided to cover an outer peripheral surface of the mass member. A propeller shaft in which the dynamic damper is assembled in the tube so that an outer peripheral portion of the body directly contacts an inner peripheral side of the tube, wherein an outer diameter of the elastic body is larger than an inner diameter of the tube. The dynamic damper is fixed to the inner peripheral side of the tubular body while compressing and elastically deforming the elastic body. The compression of the elastic body is performed by contact between the elastic body and the inner peripheral surface of the tubular body. A propeller shaft, characterized in that frictional resistance on the surface is set to be larger than the pull-out force of the dynamic damper. 2. The propeller shaft according to claim 1, wherein a plurality of elastic portions are provided on an outer peripheral side of the elastic body so as to radially protrude in a radial direction of the elastic body. 3. An elastomer comprising 100 parts by weight of an ethylene / α-olefin / non-conjugated diene copolymer rubber and 0.1% sulfur.
3. The propeller shaft according to claim 1, comprising a rubber composition containing 1 to 10 parts by weight and 25 to 100 parts by weight of carbon black. 4. The ethylene / α-olefin / non-conjugated diene copolymer rubber comprises ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated diene, and the ethylene / α-olefin has a molar ratio of ethylene / α-olefin. 65 / 35-73 /
27, the intrinsic viscosity [η] measured in decalin at 135 ° C. is 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in a state where 50 phr of a paraffinic oil is oil-extended is 0.2 to 0. The propeller shaft according to claim 3, wherein the non-conjugated diene is 5-ethylidene-2-norbornene.