JP3410743B2 - Anti-vibration rubber and its manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration rubber which is capable of preventing the occurrence of cracks due to burrs generated in a die split portion of anti-vibration rubber and improving fatigue resistance, and a method for producing the same. Is.

[0002]

2. Description of the Related Art As an anti-vibration rubber for automobile parts, such as an engine mount and an underbody bush, there is an inner / outer double cylinder type shown in a partial cross section in FIG. This is the outer cylinder a
The inner cylinder b is connected to the inner cylinder b by a rubber body c, and a stopper rubber e integral with the inner surface of the outer cylinder a is provided in the amplitude motion direction of the rubber body c with a clearance space d interposed therebetween. The rubber body c and the stopper rubber e are molded together with the outer cylinder a and the inner cylinder b by a rubber molding die that is divided at an intermediate portion in the axial direction,
At that time, a thin burr f generated at a split portion formed by the molding die is formed along a curved edge g facing the clearance space d between the rubber body c and the stopper rubber e.

[0003]

By the way, one of the deterioration phenomena of the vibration-proof rubber is a crack h generated in the rubber body c. In order to extend the life of the product, it is necessary to prevent the occurrence of such cracks h. However, no effective structure or method has been reported in this regard, and the cause of its occurrence was awaited. Then, as a result of studying the cause, it was found that the cause was the above-mentioned burr f. That is, the amplitude action in the shearing direction and the compression pulling direction of the rubber body c causes stress concentration on the burr f on the rubber body c side to cause tearing, and as a result,
It was found that cracks h were introduced into the rubber body c from this tearing portion, and that the stress concentration was large at the edge portion g on the rubber body c side, for example, at the portion connected to the outer cylinder a. . Therefore, an object of the present application is to provide a vibration-proof rubber that can effectively prevent the occurrence of cracks and a method for producing the same, based on the above-mentioned research results.

[0004]

In order to solve the above-mentioned problems, a vibration-proof rubber according to a first aspect of the present invention is characterized in that at least a part in a clearance space is formed with a rubber body and a burr is formed along a split surface of a split mold. A slit is formed by forming a barrier film, continuously connecting the anti-burr film to the side opposite to the rubber body across the clearance space, and separating the anti-burr film from at least a part of the edge of the rubber body facing the clearance space. It is characterized in that a split portion is formed into a shape, and burr is prevented from being generated at the edge portion of the rubber body along the split portion.

According to a second aspect of the present invention, in the vibration-proof rubber, when forming the burr prevention film and the rubber body, a thin weak body portion that connects the burr prevention film and at least a part of the edge portion facing the clearance space of the rubber body is integrated. It is characterized in that the dividing portion of claim 1 is formed by separating the weak body portion by a load applied at the time of first use.

According to a third aspect of the present invention, in the vibration isolating rubber according to the first aspect, the dividing portion is formed so as to include at least a portion of the edge of the rubber body facing the clearance space where stress concentration is greatest. And

According to a fourth aspect of the present invention, in the method for producing the vibration-proof rubber according to the first aspect, the molding projections for forming the clearance spaces in the split molds are respectively projected in the opposite direction, and the molding projections facing each other are formed. A narrow blade part that allows a gap for forming a molding space for the burr prevention film to be provided between the end portions and allows the portions of the end portions of the respective molding protrusions that are adjacent to the molding space of the rubber body to abut against each other. Then, the split mold is closed and the rubber is molded to form the rubber body and the burr prevention film at the same time.After that, the burr prevention film separates from the blade part from the rubber body side due to contraction of the rubber during cooling, and It is characterized in that a slit-shaped dividing portion is formed between the body and an edge portion facing the clearance space.

According to a fifth aspect of the present invention, in the method for producing the anti-vibration rubber according to the second aspect, the first and second mounting members are sandwiched between a pair of split molds, and unvulcanized rubber is filled between the split molds. In the manufacturing method of anti-vibration rubber that molds the rubber body by vulcanizing after that, the molding projections for forming the clearance space in each split mold are projected in the opposite direction, and the ends of the molding projections facing each other. A small gap for forming a molding space for the burr prevention film between the parts, and for forming a thinner weak part at the end of each molding projection adjacent to the molding space of the rubber body. , The split mold is closed and the rubber is molded to simultaneously form the rubber body and the burr prevention film so as to be continuous through the weak body part, and the weak body part is subjected to the load during the first use thereafter. To separate the burr prevention film and the rubber body clearer And forming a slit-shaped separation section between the edge facing the scan space.

[0009]

[0010]

In the anti-vibration rubber according to the first aspect of the present invention, the burr prevention film is formed along the split surface of the split mold simultaneously with the molding of the rubber body in at least a part of the clearance space. Since the slit-shaped dividing portion is formed by separating it from at least a part of the edge portion facing the clearance space of the body, burrs that may occur along the dividing surface during molding of the rubber body are separated from the dividing portion of the rubber body. It is less likely to occur at the edge along the.

In the anti-vibration rubber according to the second aspect, when the anti-burr film and the rubber body are continuously and integrally connected at the time of rubber molding by the thin weak body portion, the edge portion facing the clearance space of the rubber body forming the weak body portion. No burr is generated. This weak body portion is separated when the anti-vibration rubber is first used, and a dividing portion is formed between the burr prevention film and the edge portion of the rubber body.

In the anti-vibration rubber according to the third aspect of the present invention, the dividing portion is provided at least at a portion of the edge portion facing the clearance space of the rubber body where stress concentration is greatest, so that a burr at a portion where cracking is most likely occurs. Occurrence is prevented. Therefore, the generation of cracks can be efficiently prevented.

In the method for manufacturing the vibration-proof rubber according to the fourth aspect, when the rubber body and the burr prevention film are simultaneously formed by closing the split mold and performing rubber molding, the clearance space provided in each split mold is formed. A burr-preventing film is formed between the ends of the molding projections that face each other, and the blades are provided on the ends of the molding projections that are adjacent to the molding space of the rubber body. It abuts and makes it difficult for the burr prevention film to be continuous with the rubber body. By cooling after molding, the burr prevention film shrinks in the direction away from the rubber body, and due to this contracting force, the burr prevention film is separated from the edge part facing the clearance space of the rubber body from the blade part, and the slit-shaped dividing part is formed. It is formed.

In the method for manufacturing the anti-vibration rubber according to the fifth aspect, a molding space for the burr prevention film is formed between the mutually facing ends of the molding projections for forming the clearance space provided in each split mold. A burr-preventing film and a rubber body are formed by forming a gap and a small gap for forming a weak body portion that is continuous with the rubber body side with a smaller gap, and closing the split mold to mold the rubber. At least a part of the edge facing the clearance space is continuously and integrally formed so as to be connected via a thin weak body portion, and a load is applied to the weak body portion to separate the weak body portion during the first use thereafter, so that the The prevention film separates from the edge of the rubber body to form a dividing portion between the two.

[0015]

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing, as a first embodiment, an automobile engine mount of a bush type having an inner and outer double cylinder made of metal, viewed from the axial direction of the inner (outer) cylinder. The first mounting member 1 forming the outer cylinder is mounted on the engine side (not shown), and the second mounting member 2 is mounted on the vehicle body side (not shown). The first and second mounting members 1 and 2 are operable in a phased manner, and a rubber body 3 is baked and integrated between both members.

The rubber body 3 is formed so as to be long in a direction substantially orthogonal to the amplitude direction V, and the central second mounting member integrated portion 3a surrounds the periphery of the second mounting member 2 and is integrated, and this portion is the widest. The second mounting member integrated portion 3a
Arm portions 3b that extend in opposite directions from each other and adhere to the inner wall surface of the first mounting member 1 are continuously formed. The arm portion 3b gradually narrows toward the first mounting member 1, but the first mounting member integrated portion 3c connected to the first mounting member 1 is slightly wider.

A pair of stoppers 5 are provided on both sides of the rubber body 3 with a clearance space 4 interposed therebetween. Each stopper portion 5 is adhered to the inner wall surface of the first mounting member 1, respectively. The edge portion 6 of the rubber body 3 which faces the clearance space 4 is formed in a continuous rounded shape in order to avoid stress concentration. The rounded shape of the edge portion 6 has an inverse rounded shape with respect to the rounded portion formed by the first mounting member integral portion 3c from the second mounting member integral portion 3a to the arm portion 3b, and the curvature of this portion becomes particularly large. There is. The edge portion 7 of the stopper portion 5 which faces the clearance space 4 also has a continuous R-shaped curved shape similar to the edge portion 6.

The width of the clearance space 4 is widest in the vicinity of the arm portion 3b, and the burr prevention film 8 is continuously and integrally formed in this portion with the stopper portion 5 side. The burr prevention film 8 is formed to be much thinner than the thickness of the stopper portion 5 and continuous with the edge portion 7 along the split surface at the time of molding, but the edge portion 6 on the rubber body 3 side has a slit shape. It is separated by the dividing section 9. The formation range of the burr prevention film 8 may be the entire range of the clearance space 4, or only a part of the clearance space 4, for example, a part excluding the part corresponding to the second mounting member integrated part 3a as shown in the drawing. Good.

FIG. 2 shows a state after the rubber is filled in the rubber molding process of the vibration-proof rubber. In this figure, the anti-vibration rubber has a half section. The mold used for this molding is the first
It is composed of an upper mold 10 and a lower mold 11 which are fitted together at an intermediate portion in the length direction of the mounting member 1. Reference symbol P in the figure is a split surface. Molding projections 12 and 13, which are molding parts of the clearance space 4, are integrally formed at the corresponding positions of the upper mold 10 and the lower mold 11 so as to project toward each other.
The respective tip portions are adapted to abut on the split surface P. A cutting portion C, which will be described in detail later, is provided at this contact portion.

FIG. 3 shows a first mounting member 1 and a second mounting member 2.
3 shows a planar shape of the lower mold 11 in a state of being set as seen from the split surface side. The upper mold 10 is symmetrical with this. In the figure, the molding projection 13 planted in the lower mold 11 corresponds to the shape of the clearance space 4, and both ends 14 thereof are in contact with the inner surface of the first mounting member 1. With this molding projection 13, the first cavity 15 on the side of the second mounting member 2 and the second cavity
The second cavity 16 on the mounting member side is defined.

Further, a cutting portion C for forming the clearance space 4 is provided on the surface of each end portion 14.
However, for simplification, only the lower left one is shown. The detailed structure of the cutting portion C is shown in FIGS. 4 is an enlarged view of part A of FIG. 3, and FIG. 5 is a cross section taken along line BB of FIG. As is clear from these figures, the cutting portion C is composed of the blade portion 17, the taper portion 18, and the recessed portion 19.

The blade portion 17 is flush with the general surface of the molding projection 13, but by forming a recess 19 on the second cavity 16 side, it is formed as a narrow portion along the first cavity 15. The recess 19 communicates with the second cavity 16 and forms a molding space for the burr prevention film 8. Since the top surface of the blade portion 17 and the recess 19 are connected by the tapered portion 18, the blade portion 1
7 has a trapezoidal cross section in which the concave portion 19 side is widened.

Next, a method of manufacturing the vibration-proof rubber will be described with reference to FIG. First, in a state where the first mounting member 1 and the second mounting member 2 are set between the upper mold 10 and the lower mold 11,
Unvulcanized rubber is filled in the first cavity 15 and the second cavity 16, and the rubber is vulcanized by a conventional method. As a result, the anti-vibration rubber of FIG. 1 having the slit-shaped dividing portion 9 is obtained. At this time, the burr prevention film 8 is formed integrally with the stopper portion 5 on the split surface P of the portion forming the clearance space 4. At the same time, burrs may be formed on the mating surfaces of the upper and lower blade portions 17 that connect the burr prevention film 8 and the edge portion 6 and have a thinner wall thickness than the burr prevention film 8.

When the rubber shrinks due to cooling after the completion of vulcanization, the burr prevention film 8 is pulled toward the stopper portion 5 side by the shrinkage of the stopper portion 5 having a large volume in addition to the shrinkage of itself. Therefore, the burr prevention film 8 is cleanly separated from the edge portion 6 of the rubber body 3 at the portion having the blade portion 17. At this time, even if burrs are generated on the mating surfaces of the upper and lower blade portions 17, this thin film portion is also separated from the edge portion 6 side together with the burr prevention film 8.

In this way, since the dividing portion 9 is formed between the burr prevention film 8 and the edge portion 6 at the same time as the rubber is baked, the burr is less likely to be formed on the edge portion 6 side. Therefore, even if the stress is concentrated on the portion of the edge portion 6 along the dividing portion 9, there is no burr to be torn by this stress, and thus it is possible to prevent the conventional cracks caused by the burr. As a result, the anti-vibration rubber has improved fatigue resistance and durability.

FIG. 6 is a graph comparing the number of durable vibrations of the conventional product having burrs and the example product. As is clear from this graph, the number of durable vibrations of the product of this example is improved about three times as much as that of the conventional product.

Further, in this embodiment, by providing the tapered portion 18 between the blade portion 17 and the concave portion 19, the durability of the blade portion 17 can be improved. That is, if the thickness of the blade portion 17 is too thin, the blade portion 17 may be crushed by the impact of the molding rubber or the impact of mold clamping. Therefore, by providing the taper portion 18, a sufficient thickness against the impact is provided. Also, strength can be secured. The blade portion 17 may be provided only on either side of the upper die 10 or the lower die 11, and if provided on the upper die 10, the blade portion 17 will be set when the first attachment member, the second attachment member 2 and the like are set. It does not hurt and makes it easier to work.

A second embodiment is shown in FIGS. 7 to 9. 7 is an overall plan view, and FIGS. 8 and 9 are DD of FIG. 7, respectively.
The line and the enlarged cross section along the line EE are shown. In this example, the first mounting member 1 is in the shape of a bracket, and the rubber body 3 supports a cantilevered, cylindrical second mounting member 2. The burr prevention film 8 is directly baked on the inner wall surface of the first mounting member 1 and is connected to the rubber body 3 by the weak body portion 20 along the edge portion 6 of the arm portion 3b forming a continuous curved surface.

As is apparent from FIG. 9, the weak body portion 20 is a thin film portion which is continuously and integrally formed with the burr prevention film 8 and the rubber body 3 on the split surface P. The weak body portion 20 is formed on the mating surfaces of the upper and lower blade portions 17 in FIG. 2 of the previous embodiment, for example.
It is obtained by providing some intentional gap for forming the formation space of the. However, this wall thickness is not so thin as to be divided by the shrinkage of rubber after molding as in the previous embodiment, and is a thickness that can be divided by the load applied in the first use. However, the design of the wall thickness is appropriately made according to the application of the vibration-proof rubber so that this dividing condition is satisfied.

When the anti-vibration rubber manufactured in this manner is used, the first and second load is applied under the load applied at the first use.
The weak bodies 20 are cleanly divided along the edges 6 by the loads applied to the weak bodies 20 from the rubber body 3 and the burr prevention film 8 via the attachment members 1 and 2 of FIG. A slit-shaped dividing portion is formed between the membranes 8 similarly to the dividing portion 9 of the previous embodiment, and burrs along the edge portion 6 are less likely to occur. That is, in the previous example, the dividing portion 9 was formed by using the contracting force of rubber, whereas in the present embodiment, the dividing portion 9 is formed by using the load applied in the first use. In each case, the effect of preventing burr can be expected similarly. The reference numerals used in the description of this embodiment are the same as those in the previous embodiment.

In each of the preceding embodiments, the burr prevention film 8 and the dividing portion 9 are provided to prevent the burr from being generated. However, as another method, the burr can be removed by machining after the rubber is baked. In this method, a vibration-proof rubber is manufactured by a conventional method, and as in the conventional example shown in FIG. After that, by mechanical processing using shot blasting, buffing, and rudering, at least a portion of the burr that has occurred in the portion corresponding to the dividing portion 9 of each of the previous examples is removed. Even in this case, it is possible to prevent the occurrence of cracks in the stress concentration portion due to burrs. This is clear from the fact that the number of durable vibrations is improved about three times as compared with the conventional product, as shown in the graph of FIG. 6 described above. Moreover, since the mold can be the same as the conventional one, the mold durability can be maintained as high as the conventional one.

[0033]

According to the first aspect of the present invention, a burr prevention film is formed along the split surface of the split mold simultaneously with the molding of the rubber body in at least a part of the clearance space. Since the slit-shaped dividing portion is formed by separating from at least a part of the edge portion facing the clearance space of the body, burrs which may occur along the dividing surface during molding of the rubber body are formed in the dividing portion of the rubber body. It is less likely to occur at the edge along the line. Therefore, the occurrence of cracks due to the tearing of burrs can be prevented, and the fatigue resistance and durability of the entire vibration-proof rubber can be improved.

According to the second aspect of the present invention, at least a part of the edge portion of the rubber body facing the clearance space is connected to the burr prevention film at the time of molding the rubber to form a thin weak body portion which is separated at the first use. Therefore, it is possible to prevent the occurrence of burrs in the edge portion of the rubber body where the weak body portion is formed, and further, it is possible to form the dividing portion by utilizing the load during the first use.

According to the third aspect of the present invention, since the dividing portion is provided in at least a portion of the edge portion of the rubber body which faces the clearance space, where stress concentration is greatest, burr is generated in a portion where cracks are most likely to occur. Can be prevented, and as a result, the occurrence of cracks can be efficiently prevented.

According to the invention of claim 4, a gap which forms a space for forming a burr prevention film is provided between the mutually facing ends of the molding projection for forming the clearance space provided in each split mold, In addition, a narrow blade portion that abuts each other is provided at a portion of the end portion of each molding protrusion that is adjacent to the molding space of the rubber body, and rubber molding is performed using this split mold to form a burr prevention film on the blade portion. Since the slit-shaped dividing part was formed by separating from the rubber body with, the dividing part can be formed at the same time as rubber molding by utilizing the shrinkage force of the burr prevention film due to cooling after molding,
Easy to manufacture.

According to the fifth aspect of the present invention, for forming the molding space for the burr prevention film between the mutually facing ends of the molding projections for forming the clearance space provided in each split mold. A gap and a small gap for forming a weak body portion that is smaller than this and continuous with the rubber body side are provided. Since it was connected continuously through, and the dividing part was formed by cutting the weak part by applying a load to the weak part at the time of the first use thereafter.
Simultaneously with rubber molding, the weak body is formed integrally with the burr prevention film and the rubber body to prevent burrs from occurring at the edge of the rubber body where the weak body is formed. Parts can be formed.

[0038]

[Brief description of drawings]

FIG. 1 is a view showing a product of a first embodiment from one end surface of an axial shaft.

FIG. 2 is a partial cross-sectional view showing a manufacturing method of the first embodiment.

FIG. 3 is a plan view of a mold used in the manufacturing method of the first embodiment.

FIG. 4 is an enlarged perspective view of a portion corresponding to part A in FIG.

5 is a sectional view taken along line BB of FIG.

FIG. 6 is a graph comparing durability of the example product and the conventional product.

FIG. 7 is a view showing the product of the second embodiment from one end surface of the axial direction.

8 is an enlarged cross-sectional view taken along line DD of FIG.

9 is an enlarged sectional view taken along line EE of FIG.

FIG. 10 is a partially enlarged cross-sectional view showing a conventional example.

[Explanation of symbols]

1st mounting member 2 Second mounting member 3 rubber body 4 clearance space 6 Edge facing the clearance space of the rubber body 8 Burr prevention film 9 divisions 10 Upper mold 11 Lower mold 13 Molding protrusion 17 Blade 20 weak body C cutting part P split surface

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16F 1/38 B29D 31/02

Claims (5)

(57) [Claims] 1. A first mounting member and a second mounting member, which are mounted on different mounting objects and are movable relative to each other, and a split mold formed so as to connect between these mounting members, and a shearing direction and compression. A rubber body that is capable of swinging in the pulling direction, and a clearance space that allows swinging movement of the rubber body is formed between the first and second mounting members. Simultaneously with the molding of the rubber body, a burr prevention film is formed along the split surface of the split mold, and this burr prevention film is integrally continuous to the side opposite to the rubber body across the clearance space. By forming a slit-shaped dividing portion by separating from at least a part of the edge portion facing the clearance space,
An anti-vibration rubber, characterized in that burr is prevented from being generated at the edge of the rubber body along the divided portion. 2. A thin weak body portion that integrally connects the burr prevention film and at least a part of an edge portion of the rubber body facing the clearance space when the rubber body is molded, and integrally forms the weak body portion. The dividing portion is formed by separating the portion by a load applied at the time of first use.
Anti-vibration rubber described. 3. The dividing portion is formed so as to include at least a portion where the stress concentration is greatest among the edge portions of the rubber body which face the clearance space.
Anti-vibration rubber described. 4. An anti-vibration rubber for molding a rubber body by sandwiching the first and second mounting members between a pair of split molds, filling unvulcanized rubber between the split molds, and then vulcanizing. In the manufacturing method of 1, the molding protrusions for forming a clearance space in each split mold are projected in the opposite direction, and a gap for forming a molding space for the burr prevention film is provided between the ends of the molding protrusions facing each other. The rubber body is provided by forming the end of each of the molding protrusions into a narrow blade portion that is in contact with each other in the portion adjacent to the molding space of the rubber body, and closing the split mold to mold the rubber. And the burr prevention film are formed at the same time, and the burr prevention film is separated from the rubber part side from the blade part due to the contraction of the rubber during cooling, and a slit-shaped dividing part is formed between the edge part facing the clearance space of the rubber part. 2. The method according to claim 1, wherein The manufacturing method of the anti-vibration rubber listed. 5. An anti-vibration rubber for molding a rubber body by sandwiching the first and second mounting members between a pair of split molds and filling unvulcanized rubber between the split molds and then vulcanizing. In the manufacturing method of 1, the molding protrusions for forming a clearance space in each split mold are projected in the opposite direction, and a gap for forming a molding space for the burr prevention film is provided between the ends of the molding protrusions facing each other. By providing a small gap in the end of each molding projection adjacent to the molding space of the rubber body to form a thinner weak body, and by closing the split mold to mold the rubber. The rubber body and the burr prevention film are integrally formed at the same time so as to be continuous through the weak body part, and the weak body part is separated by the load load during the first use thereafter, and the edge facing the clearance space between the burr prevention film and the rubber body A slit-shaped dividing part is formed between The method for producing a vibration-proof rubber according to claim 2, wherein