JP3957307B2 - Stabilizer bush - Google Patents

Description

  The present invention relates to a stabilizer bush for holding a stabilizer bar of a vehicle.

  As shown in FIG. 4, the stabilizer bush is generally made of a thick-walled cylindrical rubber elastic body 1, and the stabilizer bar S of the vehicle is inserted and held in the cylinder. The rubber elastic body 1 has a flat top surface and flanges 11 that project radially from both end edges in the axial direction. The outer peripheral surface between the flanges 11 is placed in a substantially U-shaped bracket B. It is made to hold. The bracket B is fixed to a vehicle body (not shown) by inserting bolts into the mounting holes B1 at both ends.

  The rubber elastic body 1 is conventionally made of a natural rubber material. However, when the vehicle starts or when the operating angle of the stabilizer bar S is large, the inner peripheral surface of the rubber elastic body 1 and the stabilizer bar S may suddenly be relatively displaced, and noise may be generated. For this reason, it has been proposed that the rubber elastic body 1 is made of a highly slidable rubber for the purpose of reducing sliding resistance with the stabilizer bar S and suppressing abnormal noise. However, if a high slidable rubber is used, the coefficient of friction with the bracket B or the vehicle body that comes into contact with the outer peripheral surface decreases, so that the rubber elastic body 1 slides sideways as shown in FIG. When the rubber elastic body 1 abuts on the bending portion S1, the rubber elastic body 1 may be laterally displaced with respect to the bracket B due to the lateral force from the stabilizer bar S. In order to prevent this, it is conceivable to provide a lateral displacement prevention stopper adjacent to the rubber elastic body 1, but there is a problem that the number of parts increases and the cost increases.

  Therefore, the present inventors previously made a cylindrical inner layer rubber made of a highly slidable rubber and serving as a holding portion of the stabilizer bar and laminated on the outer peripheral side in order to prevent the occurrence of abnormal noise and lateral deviation. The stabilizer bush which consists of the outer layer rubber | gum formed was proposed (Japanese Patent Application No. 9-67380). The highly slidable rubber composing the inner layer rubber is made by blending a higher fatty acid amide such as oleic acid amide in a predetermined ratio with a base rubber, for example, a blend rubber of natural rubber and butadiene rubber (NR / BR). Thus, the sliding resistance can be reduced by the action of oleic acid amide as a lubricant.

  Further, since the outer layer rubber is made of a conventional rubber material, it is possible to prevent the occurrence of lateral displacement. At this time, increasing the difference in SP value (solubility parameter) between the outer layer rubber and oleic acid amide has the effect of suppressing the migration of oleic acid amide to the outer layer rubber side, and the gas permeability of the outer layer rubber is particularly low. Since the effect is great, the use of butyl rubber (IIR) has been studied. However, when butyl rubber is used for the outer layer rubber, the adhesion between the inner and outer layers is unstable, and the fatigue resistance is inferior to that of natural rubber. Is likely to occur, and the durability is not always sufficient.

  Accordingly, an object of the present invention is to provide a stabilizer bushing that can prevent the occurrence of abnormal noise and lateral deviation, and has improved the durability of the inner layer and outer layer, the outer layer rubber, and the fatigue resistance of the outer layer rubber. .

The stabilizer bush of the present invention is
In a stabilizer bush that is configured to insert and hold a stabilizer bar in a cylinder of a rubber elastic body formed into a cylindrical shape, and to hold an outer peripheral surface of the rubber elastic body with a bracket attached to a vehicle body,
The rubber elastic body is made of a highly slidable rubber and has a cylindrical inner layer rubber which is a holding portion of the stabilizer bar, and is laminated on the outer periphery of the inner layer rubber and is similar to the base rubber of the highly slidable rubber. It has a two-layer structure with an outer layer rubber made of a rubber material, and the rubber hardness of the outer layer rubber is equal to or higher than the rubber hardness of the inner layer rubber ,
Protruding portions projecting radially are provided on the outer peripheral edges of the inner rubber layer in the axial direction, the outer peripheral shape of the convex portion is a circular cross section, and the outer peripheral shape of the inner rubber portion located between the pair of convex portions Is a polygonal cross section,
Provide flanges projecting radially at both ends in the axial direction of the outer layer rubber,
A shaft of the outer layer rubber is connected to an end surface facing the inner side in the axial direction of the inner rubber layer and an outer peripheral surface of the convex portion connected to an end surface facing the inner side in the axial direction of the inner layer rubber among both axial end surfaces of the convex portion. The inner surface of the end portion in the direction is joined, and the convex portion is covered with the flange.

  According to the above configuration, since the inner layer rubber in contact with the stabilizer bar is made of a highly slidable rubber and the outer layer rubber on the bracket side is made of a conventional rubber material, the sliding resistance of the stabilizer bar is reduced. While suppressing the generation of abnormal noise, the frictional resistance with the bracket can be increased to prevent lateral displacement. In addition, since the outer layer rubber is composed of a rubber material similar to the base rubber of the highly slidable rubber, the adhesion to the inner layer rubber is enhanced, and the rubber hardness of the outer layer rubber is further increased. Since it is above the hardness, the rigidity is increased and the durability is improved. In addition, due to the high rigidity, even if the highly slidable rubber moves to the outer layer rubber side, the lateral displacement can be sufficiently suppressed, and the spring becomes high, so the stabilizer bar can be used to obtain the conventional spring characteristics. By reducing the diameter, the weight of the apparatus can be reduced.

  Specifically, it is preferable that the base rubber of the highly slidable rubber is a blend rubber of natural rubber and butadiene rubber and the outer layer rubber is made of a natural rubber-based rubber material. Natural rubber-based materials are excellent in fatigue resistance and prevent the occurrence of crevices and enhance durability.

  Specifically, the high-sliding rubber is obtained by blending a higher fatty acid amide with the base rubber (claim 3). The higher fatty acid amide blooms during use, functions as a lubricant, and improves slidability.

The outer peripheral shape of the inner rubber layer is preferably a polygonal cross section (Claim 1) . Or the convex part which protrudes in a radial direction is formed in the both-ends outer periphery of the axial direction of the said inner layer rubber | gum (Claim 1). Due to the effect of these shapes, it is possible to prevent displacement and rotation at the adhesion interface, and to further improve the bondability between the inner and outer layers.

  1 (a) to 1 (c) show an embodiment of a stabilizer bush of the present invention. As shown in FIGS. 1 (b) and 1 (c), the thick-walled cylindrical rubber elastic body 1 constituting the stabilizer bush is made of a highly slidable rubber, an inner layer rubber 1A serving as a holding portion of the stabilizer bar, and an outer periphery thereof. The outer layer rubber 1B is formed in a two-layer structure. The outer layer rubber 1B is formed in a substantially U-shaped cross section with the top surface being a flat surface, and the outer peripheral edges of both end portions are extended in the radial direction to form flanges 11. And the outer peripheral surface between these flanges 11 is made to hold | maintain to the substantially U-shaped attachment bracket B (refer FIG. 4) fixed to the vehicle frame with a volt | bolt.

  The inner rubber layer 1A is substantially cylindrical, and the stabilizer bar S (see FIG. 4) is inserted and held in a circular cylinder. The outer peripheral surface 12 to be joined to the outer layer rubber 1B is formed in a polygonal cross section in order to enhance the bondability with the outer layer rubber 1B. Here, the outer peripheral surface 12 has a regular octagonal cross section, but is not necessarily limited thereto, and may have another shape. Further, on both end faces in the axial direction, the outer peripheral edge of the inner layer rubber 1A protrudes radially outward to form a flange-like convex portion 13, which further enhances the bondability (FIG. 1 (a), (C)). The convex portion 13 is not necessarily formed on the entire circumference of the outer peripheral edge, and may be formed partially.

  The highly slidable rubber constituting the inner layer rubber 1A is provided with high slidability by blending a higher fatty acid amide with the rubber as the base material. The base rubber is not particularly limited. For example, natural rubber (NR), butadiene rubber (BR), blend rubber of natural rubber and butadiene rubber (NR / BR), isoprene rubber (IR), styrene butadiene rubber ( SBR), chloroprene rubber (CR), nitrile rubber (NBR), ethylene propylene diene copolymer rubber (EPDM), butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), and blended rubbers thereof can be used. Preferably, a blend rubber (NR / BR) of natural rubber and butadiene rubber is suitably used.

The higher fatty acid amide blended in the base rubber of the high slidable rubber functions as a lubricant by blooming from the base rubber during use and improves the slidability. Specific examples of higher fatty acid amides include saturated and unsaturated fatty acid amides having 12 to 22 carbon atoms such as oleic acid amide, palmitic acid amide, stearic acid amide, erucic acid amide, and preferably oleic acid amide Is used.
The blending amount of the higher fatty acid amide in the inner layer rubber 1A is desirably set to a necessary amount when the rubber elastic body 1 is composed of only a high sliding rubber. However, if the amount of the higher fatty acid amide kneaded into the inner layer rubber 1A becomes too large, there is a risk of adversely affecting the rubber physical properties. Usually, the blending amount of the higher fatty acid amide in the base rubber is 5 to 30% by weight. % Range. When the amount of the higher fatty acid amide is large, an excessive higher fatty acid amide can be kneaded in advance in the outer layer rubber 1B.

  The highly slidable rubber is formed by blending the base rubber and the higher fatty acid amide at a predetermined blending ratio. At this time, generally known additives such as a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, and a processing aid can be used. Examples of the vulcanizing agent include sulfur, peroxide, metal oxide, polyamine and the like, and are usually used in the range of 0.1 to 10% by weight. As the vulcanization accelerator, sulfenamide, thiazole, thiuram, dithiocarbamate, xanthate, etc. are usually used in the range of 0.1 to 10% by weight. As the vulcanization aid, zinc oxide or the like is usually used, and the blending amount is usually in the range of 3 to 15% by weight. As processing aids, fatty acids such as stearic acid and fatty oils are used.

  The outer layer rubber 1B is made of the same or similar rubber material as the base rubber of the inner layer rubber 1A. Specifically, for example, when a blend rubber (NR / BR) of natural rubber and butadiene rubber is used as the base rubber of the inner layer rubber 1A, natural rubber (NR), butadiene rubber (BR), or natural rubber A blend rubber of rubber and butadiene rubber (NR / BR) or the like can be used, and the bondability between the two is improved. In particular, it is preferable that the outer layer rubber 1B is made of a natural rubber material because fatigue resistance is high and durability is improved.

  In the present invention, the rubber hardness of the outer rubber layer 1B is set to be equal to or higher than the rubber hardness of the inner rubber layer 1A to improve the rigidity of the rubber elastic body 1 as a whole. Usually, in order to improve the wear resistance, the high-sliding rubber has a rubber hardness of about Hs65. Therefore, the outer layer rubber 1B is blended so that the rubber hardness is about Hs65 or more. The high slidability rubber gives slidability by blooming the higher fatty acid amide from the inside when the stabilizer bush is used. Depending on the combination of the inner layer rubber 1A and the outer layer rubber 1B, the blooming higher fatty acid amide may be used. May move to the base rubber outer layer rubber 1B side. Even in such a case, the lateral displacement from the bracket of the stabilizer bush can be suppressed by increasing the rigidity of the rubber elastic body 1 and the flange 11.

  When manufacturing the stabilizer bush having the above structure, first, one of the inner layer rubber 1A and the outer layer rubber 1B is molded, vulcanized or semi-vulcanized, and then the other one is injected into the mold. What is necessary is just to vulcanize-mold. Of course, each rubber may be formed into a predetermined shape and then bonded.

  According to the above configuration, since the inner layer rubber 1A that holds the outer periphery of the stabilizer bar is made of a highly slidable rubber, the sliding resistance of the stabilizer bar is reduced and the generation of abnormal noise can be prevented. On the other hand, the outer layer rubber 1B that comes into contact with the bracket and the vehicle body is made of a natural rubber-based rubber material. Therefore, the friction resistance between the two is large, and the rigidity is improved by the high hardness. Even if the higher fatty acid amide migrates, lateral displacement from the bracket hardly occurs. In addition, natural rubber is excellent in fatigue resistance, so that it is difficult to generate crevices and the like, and the durability is greatly improved. Furthermore, since the inner layer rubber 1A and the outer layer rubber 1B are made of similar rubber materials, the adhesiveness is good. Moreover, since the outer peripheral surface 12 of the inner layer rubber 1A has a polygonal cross section and the convex portions 13 are provided on both end surfaces, it acts as a displacement stop and a rotation stop at the bonding interface, and further improves the bondability. Has an effect.

  FIG. 2 shows the effect of preventing the lateral displacement of the stabilizer bush having the above-described configuration. In the figure, the stabilizer bush shown as the product 1 of the present invention uses a highly slidable rubber in which a natural rubber material is an outer layer rubber 1B and an NR / BR rubber is blended with oleic amide as an inner layer rubber 1A. 1. The outer layer rubber 1B has a rubber hardness of Hs80, and the inner layer rubber 1A has a rubber hardness of Hs65. FIG. 2 shows the removal load of the stabilizer bush on the vertical axis and the pull-out durability on the horizontal axis (product of the present invention 1: ●). The pull-out load is the load (unit: N) when a lateral displacement (displacement of the stabilizer bush from the bracket) occurs when a static load is applied to the stabilizer bush. The pull-out durability is measured at one end of the stabilizer bar. It is shown by the number of times until horizontal shift or crease occurs after repeated vertical input equivalent to the maximum stroke.

  As is apparent from FIG. 2, in the product 1 of the present invention, a stabilizer bush (conventional product) composed only of a highly slidable rubber (NR / BR rubber blended with oleic acid amide; Hs65) in terms of the pulling load and the pull-out durability. 1: □) is significantly improved, and a great effect is obtained in preventing lateral displacement. In particular, the conventional product 1 has a durability of 20,000 times or more, whereas the conventional product 1 has a lateral deviation after about 3000 times and a crack is generated in the flange portion. Further, the same test was performed on the product obtained by using the product 1 of the present invention for a certain period and shifting the oleamide in the inner layer rubber 1A to the outer layer rubber 1B to the equilibrium state (product 2: present invention). However, although the punching load was lower than that of the product 1 of the present invention, it was much higher than that of the conventional product 1, and the pull-out durability was 20,000 times or more and was the same as that of the product 1 of the present invention.

  In the case of a stabilizer bush made of a conventional highly slidable rubber, if the rubber hardness is lowered by placing importance on the riding comfort (conventional product 2: Δ), the pulling load and the pulling durability are greatly reduced. Here, the conventional product 2 is made of a highly slidable rubber prepared by blending oleic acid amide with NR / BR rubber, and the rubber hardness is Hs55. On the other hand, the configuration of the present invention significantly improves the pulling load and the pulling durability, so that the rubber hardness of the inner and outer layer rubbers is higher than that of the present products 1 and 2 so that the above-mentioned conventional product has two levels of characteristics. Even if it is set to a low value, it is possible to make the removal durability equal to or more than the target durability number (the number of removal durability times of the conventional product 1). Therefore, it is possible to improve the ride comfort while preventing lateral displacement.

  FIG. 3 shows the spring characteristics of the present invention product 1 and the conventional products 1 and 2 in the state where they are assembled to the stabilizer bar, the spring characteristics of the stabilizer bush alone (vertical static spring characteristics). Is shown in the graph with the horizontal axis. As shown by the solid line in FIG. 3, when the stabilizer bush of the product 1 of the present invention is assembled to the current stabilizer bar (φ26.5), the spring characteristics in the state of being assembled to the stabilizer bar used the conventional product 1. Higher than the case. In order to satisfy the same level of spring characteristics as the conventional product 1 by using the stabilizer bush of the product 1 of the present invention, it is conceivable to reduce the weight of the stabilizer bar by reducing the diameter of the stabilizer bar. When φ25.4) is used (dotted line in FIG. 3), the target characteristic (spring characteristic when the conventional product 1 is assembled to the current stabilizer bar (φ26.5)) can be obtained (dotted line in FIG. 3). That is, by using the stabilizer bush of the present invention, there is an advantage that it is possible to reduce the weight by reducing the diameter of the stabilizer bar while maintaining the same characteristics as the conventional one.

1 shows an embodiment of the present invention, (a) is a front view in the axial direction of a stabilizer bush, (b) is a cross-sectional view in a direction perpendicular to the axis of the stabilizer bush, and (c) is a cross-sectional view in the axial direction of the stabilizer bush. It is. It is a figure which shows the horizontal shift prevention effect of this invention goods. It is a figure which shows the weight reduction effect by this invention goods. It is a perspective view which shows the state which assembled the conventional stabilizer bush to the stabilizer bar. It is a fragmentary sectional view showing the state where the conventional stabilizer bush was attached to the stabilizer bar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber elastic body 1A Inner layer rubber 1B Outer layer rubber 11 Flange 12 Outer peripheral surface 13 Convex part B Bracket S Stabilizer bar S1 Curved part

Claims (3)

In a stabilizer bush that is configured to insert and hold a stabilizer bar in a cylinder of a rubber elastic body formed into a cylindrical shape, and to hold an outer peripheral surface of the rubber elastic body with a bracket attached to a vehicle body,
The rubber elastic body is made of a highly slidable rubber and has a cylindrical inner layer rubber which is a holding portion of the stabilizer bar, and is laminated on the outer periphery of the inner layer rubber and is similar to the base rubber of the highly slidable rubber. It has a two-layer structure with an outer layer rubber made of a rubber material, and the rubber hardness of the outer layer rubber is equal to or higher than the rubber hardness of the inner layer rubber ,
Protruding portions projecting radially are provided on the outer peripheral edges of the inner rubber layer in the axial direction, the outer peripheral shape of the convex portion is a circular cross section, and the outer peripheral shape of the inner rubber portion located between the pair of convex portions Is a polygonal cross section,
Provide flanges projecting radially at both ends in the axial direction of the outer layer rubber,
A shaft of the outer layer rubber is connected to an end surface facing the inner side in the axial direction of the inner rubber layer and an outer peripheral surface of the convex portion connected to an end surface facing the inner side in the axial direction of the inner layer rubber among both axial end surfaces of the convex portion. The stabilizer bush which joined the inner surface of the edge part of a direction, and has covered the said convex-shaped part with the said flange. The stabilizer bush according to claim 1, wherein the base rubber of the high slidable rubber is a blend rubber of natural rubber and butadiene rubber, and the outer layer rubber is made of a natural rubber-based rubber material.   The stabilizer bush according to claim 1 or 2, wherein the highly slidable rubber is obtained by blending a higher fatty acid amide with the base rubber.

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