JP2002357244A - Torsional damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple press-fitting type torsional damper having superior materiality after heat-aged and increasing sliding torque substantially. SOLUTION: In the torsional damper (pulley body) 10 having a structure integrally assembling a hub 12 and mass 14 by press-fitting a rubber elastic body 16 between the hub (pulley body) 12 and the mass (damper mass) 14 from one side of an axial direction, the rubber elastic body 16 is formed by vulcanized rubber in which xanthate denatured polychloroprene or mercaptan denatured polychloroprene is provided as a rubber component and at least zincoxide and trimethylthiourea are provided as a vulcanizing aid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torsional damper, and more particularly to a hub and a mass which are press-fitted from one side in the axial direction between the hub and the mass, whereby the hub and the mass are integrally assembled. The present invention relates to a so-called simple press-fit type torsion damper having a structure.

[0002]

2. Description of the Related Art Generally, when a crankshaft or the like of an internal combustion engine is rotated, complicated torsional vibrations are inevitably generated, so that the crankshaft itself may be damaged or the internal combustion engine may be damaged. Vibration and noise may be caused. Therefore, conventionally, in order to avoid such fears in the engine of a vehicle,
A structure in which a torsional damper is attached to a rotating shaft such as a crankshaft has been adopted.

In such a torsion damper, a metal pulley main body (hub) having a boss portion fixed to a rotating shaft such as a crankshaft generally has a radius relative to the pulley main body. A cylindrical rubber made of an elastic material such as rubber as a buffer is provided between the pulley main body and the damper mass. It has a structure in which an elastic body is interposed, and as a damper pulley, the rubber elastic body can absorb torsional vibration around the axis of the crankshaft.
Problems such as the damage of the rotating shaft such as the crankshaft and the vibration and noise of the engine as described above can be advantageously solved.

When manufacturing a torsional damper having such a structure, a predetermined rubber elastic body is press-fitted between the pulley body and the damper mass rather than an adhesive structure using an adhesive from the viewpoint of cost reduction. The simple press-fit type structure has been adopted advantageously, and it has become the mainstream at present.However, in this kind of simple press-fit type torsional damper, when a heavy load is applied, Between the pulley body and the rubber elastic body as a product, or between the damper mass and the rubber elastic body as a metal product, there is an inconvenience of slippage in the rotational direction, and therefore, in order to prevent such slippage, It is required to take some measures to increase the slip torque, and in particular, due to the trend toward higher engine output in recent years, the required value of the slip torque is increasing.

[0005] By the way, measures considered to be effective against the improvement of the sliding torque include (1) an increase in the compression reaction force of the rubber elastic body compressed between the pulley body and the damper mass, and (2) a rubber. Reduction of compression set of elastic body,
(3) An increase in the coefficient of friction (μ) between the rubber elastic body and the pulley body or the damper mass, which is a metal product (fitting), can be mentioned. Usually, the compression reaction force (1) of the rubber elastic body is
There is a problem that the maximum value is determined from the characteristics (f _n ) of the rubber material and the production capacity, and there is a problem that the degree of freedom in design is restricted, and a measure for reducing the compression set of the rubber elastic body (2) In the case where the torsion damper is applied to a crankshaft or the like and is exposed to severe thermal conditions, it is not possible to use a rubber material that greatly affects slippage and durability after thermal deterioration, Therefore, conventionally, use of EPDM or acrylic rubber is merely considered.

However, although rubber materials such as EPDM and acrylic rubber are excellent in terms of compression set, the value of the coefficient of friction (3) between a metal product (metal fitting) and a rubber elastic body is lower than that of a rubber material. It falls into a low class among the materials, and the absolute value of the slip torque value is at a low level, and the problem is that the initial slip torque is not sufficient.

For this reason, when the rubber elastic body is made of EPDM or acrylic rubber, at least the press-fitting surface of the rubber elastic body of the pulley body or the damper mass, which is a metal fitting, is subjected to shot blasting or chemical polishing. The surface roughness is increased to increase the sliding torque. However, the adoption of such a surface roughening process also leads to an increase in the number of metal fitting processing steps. The problem is that it raises costs.

[0008]

Here, the present invention has been made in view of such circumstances, and it is an object of the present invention to provide excellent physical properties even after heat aging and to greatly reduce the slip torque value. It is another object of the present invention to provide a simple press-fit type torsional damper that has an increased sliding torque. Provided is a simple press-fit type torsional damper.

[0009]

According to the present invention, in order to solve such a problem, a rubber elastic body is press-fitted from one side in the axial direction between the hub and the mass, so that the hub and the mass are press-fitted. In a torsional damper having a structure integrally assembled, the rubber elastic body is obtained by using xanthate-modified polychloroprene or mercaptan-modified polychloroprene as a rubber component, and using at least zinc oxide and trimethylthiourea as a vulcanization system. A torsional damper characterized by being composed of vulcanized rubber,
This is the gist.

In short, the present invention is based on the results of various studies on a friction coefficient (μ), which is an important characteristic of a rubber elastic body in a simple press-fit type torsional damper, and a rubber material excellent in compression set. The vulcanized rubber obtained by using the chloroprene rubber component and vulcanizing it with a specific vulcanization system has excellent compression set characteristics and has a significantly high friction coefficient with metal fittings. It has been completed based on the finding that it has a sliding torque value twice or more that of a conventional rubber material such as EPDM.

Therefore, in the torsion damper according to the present invention, the rubber elastic body constituting the torsion damper is provided with excellent heat resistance, and its rubber physical properties, particularly, compression set after heat aging are kept low. Because of the superior properties of being obtained, even if it is placed under severe thermal conditions as an engine part or the like, it is possible to effectively avoid being greatly affected by durability, Moreover,
By realizing a high coefficient of friction, even with a simple press-fit type,
From the point where a high slip torque value can be realized,
It was able to sufficiently respond to the high demands caused by the high output of the engine.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to clarify the structure of the present invention more specifically, representative embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 schematically shows a damper pulley 10 as an example of a torsional damper according to the present invention in the form of an axial sectional view. And
The damper pulley 10 includes a pulley body 12 as a hub, a damper mass 14 serving as a mass (mass body),
The rubber elastic body 16 is press-fitted between them.

More specifically, the damper pulley 10
The pulley body 12 is made of a metal material such as iron, and has a small-diameter cylindrical boss portion 20 in which a key groove 18 is provided on the inner peripheral surface at the center thereof.
Outside the boss portion 20 in the radial direction, a large-diameter cylindrical portion 22 having an outer peripheral surface as a cylindrical surface is concentrically positioned at a predetermined distance in the radial direction. The cylindrical portion 22 is integrally connected by an annular plate-shaped connecting portion 24 positioned between the cylindrical portions 22.

The cylindrical portion 22 constituting the pulley main body 12 has a thick cylindrical shape as a whole on a radially outer side, and has an endless V-belt wound around the outer peripheral surface, and extends in the circumferential direction. The damper mass 14 having the plurality of V-shaped grooves 26 formed therein is separated from the cylindrical portion 22 by a predetermined distance.
Due to the concentric arrangement, an annular gap is formed between the cylindrical portion 22 and the damper mass 14. In addition, this damper mass 14,
Like the pulley body 12, it is made of a metal material such as iron.

The cylindrical portion 2 of the pulley body 12
An annular rubber elastic body 16 is press-fitted into the annular gap between the damper mass 2 and the damper mass 14 by the same press-fitting operation as in the related art, and is interposed, thereby forming the cylindrical portion 22 The damper mass 14 has a structure integrally connected by a rubber elastic body 16. Since the rubber elastic body 16 is compressed and interposed by the press-fitting operation, the rubber elastic body 16 is provided with a rubber elastic body such that a predetermined compression allowance (press-fit allowance) can be ensured as in the related art. The shape and dimensions of the body 16 are set.

Therefore, the damper pulley 1 having the above-described structure is used.
0, the boss 20 of the pulley body 12
Attached to a rotating shaft such as a crankshaft of a predetermined internal combustion engine (not shown) and rotated integrally therewith, an endless V-belt (not shown) is wound around a V-groove 26 provided in the damper mass 14. As a result, the driving force (rotation torque) from the crankshaft or the like is transmitted to various auxiliary devices (not shown), and is used as a V-belt driving pulley.
In such a mounted state, the damper mass 14 is elastically connected to the pulley main body 12 via the rubber elastic body 16 so that the damper mass 1
The four and the rubber elastic body 16 constitute one vibration system that can function as a dynamic vibration absorber (damper mechanism) against torsional vibration of a crankshaft or the like to which the pulley body 12 is attached. It is.

Incidentally, in the damper pulley 10 employing this type of simple press-fit type structure, the rubber elastic body 16 has the cylindrical portion 22 of the pulley body 12 and the damper mass 1.
4, the relative position between the rubber elastic body 16 and the cylindrical portion 22 or the damper mass 14 is determined by the reaction force of such compression. Therefore, in the present invention, the slip torque between them becomes an important static strength, and therefore, in order to cope with a high load, a high slip torque value needs to be realized. In order to improve the slip torque value and to suppress or prevent the deterioration of the characteristics even under severe thermal conditions, and to improve the durability, a specific rubber component is specified. The rubber elastic body 16 is constituted by the vulcanized rubber obtained by vulcanization in the vulcanization system of (1).

That is, the specific rubber component that provides the vulcanized rubber constituting the rubber elastic body 16 is xanthate-modified polychloroprene or mercaptan-modified polychloroprene, in which xanthate-modified polychloroprene is It is obtained by subjecting chloroprene to emulsion polymerization in the presence of a dialkylxanthogen disulfide such as diethylxanthogen disulfide as a molecular weight regulator, and mercaptan-modified polychloroprene is used as a molecular weight regulator in the emulsion polymerization of chloroprene. , And those obtained using mercaptans such as dodecyl mercaptan. As the xanthate-modified polychloroprene and the mercaptan-modified polychloroprene, commercially available ones are appropriately selected. , It can be used.

When the specific rubber component is vulcanized to obtain the desired rubber elastic body 16, various vulcanizations conventionally used for vulcanization of the rubber component are used. In the present invention, among the vulcanizing agents and vulcanization accelerators, in particular, at least zinc oxide (Zn
O), and as a vulcanization accelerator, a vulcanization system using trimethylthiourea is adopted, and by using a vulcanized rubber obtained by combining a specific vulcanization system for those specific rubber components, For the first time, excellent sliding torque characteristics can be realized, and sliding and durability after thermal deterioration can be improved.

The amount of zinc oxide used as a vulcanizing agent and the amount of trimethylthiourea used as a vulcanization accelerator are appropriately determined according to vulcanization conditions and vulcanizate properties. Generally, zinc oxide as a vulcanizing agent is used in a proportion of about 3 to 15 parts by weight based on 100 parts by weight of a rubber component, and trimethylthiourea as a vulcanization accelerator is used in an amount of 100 parts by weight of a rubber component. For
Generally, it is used in a ratio of about 0.5 to 5 parts by weight.

However, in the present invention, the vulcanization system only needs to include at least a vulcanizing agent: zinc oxide and a vulcanization accelerator: trimethylthiourea. Other vulcanizing agents and vulcanization accelerators can be used as needed, as long as they do not adversely affect the vulcanization effect of the combination of accelerators. 3-diphenylguanidine, 1,3-
It is possible to use a vulcanization accelerator such as a guanidine type such as diortitolyl guanidine; a thiuram type such as tetramethylthiuram disulfide or tetraethylthiuram disulfide; or a thiazole type such as 2-mercaptobenzothiazole or benzothiazolyl disulfide. It is.

In the vulcanization of the rubber component, various additives conventionally used for chloroprene rubber are appropriately compounded in addition to the vulcanization system as described above. Such additives include:
Specifically, reinforcing materials, softeners, processing aids, anti-aging agents,
Fillers and the like can be mentioned.

Among these additives, carbon black, silica or the like is used as a reinforcing material, and depending on the blending of such a reinforcing material, crosslinking such as tensile strength, hardness, tear strength and abrasion can be achieved. It is possible to improve the material-mechanical properties. In addition, chloroprene rubber is a polymer that is crystalline and has high cohesive strength, and has high mechanical strength compared to other rubbers. Since there is an advantage that the amount can be reduced, the specific amount of the reinforcing material is about 20 to 80 parts by weight based on 100 parts by weight of the rubber component.

Further, as the softener, process oil,
Lubricating oil, paraffin, liquid paraffin, petroleum, asphalt, petroleum-based softening agents such as petrolatum; castor oil, linseed oil, rapeseed oil, coconut oil and other fatty oil-based softening agents are used,
The amount of the rubber component is generally limited to about 40 parts by weight based on 100 parts by weight of the rubber component. Further, as a processing aid, a fatty acid such as stearic acid is used, which serves as a lubricant between the added inorganic substance and the rubber component, and the compounding amount is usually 100 parts by weight of the rubber component. , About 0.1 to 5 parts by weight.

In addition, as anti-aging agents, amines,
Phenolic, imidazole, metal carbamate,
Wax and the like, which are generally one of the rubber components.
It is used in an amount of about 0.5 to 8 parts by weight with respect to 00 parts by weight. In addition, as the filler, in addition to the above-mentioned reinforcing material, calcium carbonate, clay, talc, and the like can be used, and the proportion is generally up to about 100 parts by weight with respect to 100 parts by weight of the rubber component. Can be blended.

The rubber elastic body 16 according to the present invention is obtained from the rubber compound prepared by using the above-mentioned specific rubber component and the specific vulcanization system, into which such additives are blended as required. However, the vulcanization temperature and the vulcanization time at that time are to be appropriately adopted, for example, as the vulcanization temperature, , 150 to 180 ° C.

The rubber elastic body 16 made of vulcanized rubber thus obtained has an annular shape and is formed between the cylindrical portion 22 of the pulley body 12 and the damper mass 14 shown in FIG. As described above, the pulley body 12 and the damper mass 14 are press-fitted into the space having a ring shape as a whole with a predetermined press-in allowance in a conventional manner.
Are connected by a rubber elastic body 16 to complete an integrated structure (damper pulley 10).

[0029]

EXAMPLES Examples of the present invention will be described below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. That goes without saying. Further, in addition to the following examples, the present invention may further include various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. , Improvements and the like can be added.

First, using the following two rubber compounds (CR compound and EPDM compound), an annular rubber elastic body 16 used in the damper pulley 10 shown in FIG.
Each was vulcanized and formed according to a conventional method. A rubber elastic body 16 composed of a vulcanized rubber according to the present invention is formed from the CR compound of the two rubber compounds.
A conventional rubber elastic body 16 as a comparative example was formed from the M compound. The vulcanization conditions for each rubber compound are as follows:
160 ° C. × 20 minutes. CR compounding amount (parts by weight) mercaptan-modified polychloroprene 100 stearic acid 1 magnesium oxide 4 antioxidant 6C 2 SRF carbon black 60 aroma oil 15 zinc oxide 5 trimethylthiourea 1.5 EPDM compounding amount (parts by weight) EPDM 100 stearin Acid 5 zinc oxide 1 antioxidant RD 1 antioxidant MB 4 HAF carbon black 50 naphthenic oil 20 dicumyl peroxide (40%) 7

The effect of thermal deterioration of the rubber properties of the test pieces (vulcanized rubber) obtained by using the above two rubber compounds was investigated. As shown in Table 1 below, The vulcanized rubber obtained from the CR compound, which is a rubber compound according to the above, has a remarkably high initial friction coefficient and a low compression set after heat aging, as compared with a vulcanized rubber having a conventional EPDM compound. And excellent heat resistance was recognized. Also, in the variation of the friction coefficient, the vulcanized rubber obtained from the CR compound is smaller than that of the EPDM compound,
It was also found that the fluctuation of the sliding torque characteristics was reduced.

[0032]

[Table 1]

Next, using each of the annular rubber elastic bodies 16 obtained from the two rubber compounds, a gap formed between the cylindrical portion 22 of the pulley body 12 and the damper mass 14 shown in FIG. In the same manner as before, 36.6
% Of the pulley body 12
By assembling the damper mass 14 with the
The intended damper pulley 10 was completed.

The slip torque of the two types of damper pulleys 10 after heat degradation at 120 ° C. × 1000 hours was measured. The rubber elastic body 16 obtained by using the CR compound according to the present invention was press-fitted. The slipper torque value of the damper pulley 10 was 600 Nm, whereas the rubber elastic body 16 obtained from the EPDM compound as a comparative example was press-fitted.
, The slip torque was only 300 N · m.

Further, instead of the mercaptan-modified polychloroprene as the rubber component in the above example, xanthate-modified polychloroprene was used, and vulcanization molding (use of zinc oxide and trimethylthiourea) was carried out in the same manner as described above. An annular rubber elastic body 16 was obtained.

Then, the obtained rubber elastic body 16 was evaluated in the same manner as described above. As a result, the rubber elastic body 16 was excellent in heat resistance and had a sliding torque value as compared with a vulcanized rubber made of conventional EPDM. It had a value of twice or more.

[0037]

As is clear from the above description, in the torsional damper according to the present invention, the rubber elastic body pressed into the gap between the hub and the mass is made of xanthate-modified polychloroprene or mercaptan. The modified polychloroprene is used as the rubber component, and the vulcanization system is composed of vulcanized rubber obtained using at least zinc oxide and trimethylthiourea. In addition, the hub, the friction coefficient between the mass and the rubber elastic body can be effectively increased,
It has become possible to greatly increase the value of the sliding torque between them, and such a sliding torque is extremely excellent in heat resistance and durability. Thus, it is possible to realize a torsional damper that is unlikely to cause slippage in the rotational direction with respect to the (hub, mass) and can exhibit excellent vibration absorption performance even under a high load.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of a damper pulley according to an embodiment of a torsional damper of the present invention.

[Description of Signs] 10 Damper pulley 12 Pulley main body 14 Damper mass 16 Rubber elastic body 18 Key groove 20 Boss part 22 Cylindrical part 24 Connecting part 26 V groove

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigemitsu Hattori 3-1, Higashi 3-chome, Komaki-shi, Aichi F-term (reference) 4J002 AC091 AC111 DE106 EV127 FD146 FD147 GN00

Claims (1)

[Claims] 1. A torsional damper having a structure in which a rubber elastic body is press-fitted between a hub and a mass from one side in an axial direction to integrally assemble the hub and the mass. A torsional damper characterized by comprising a vulcanized rubber obtained by using xanthate-modified polychloroprene or mercaptan-modified polychloroprene as a rubber component, and using at least zinc oxide and trimethylthiourea as a vulcanization system.