JP5730088B2 - Lower surface plate for air spring, method for manufacturing the same, and air spring for vehicle - Google Patents

Description

  The present invention relates to a bottom plate used for a vehicle air spring, which is used as a shock absorber for a railway vehicle mainly employing a bolsterless carriage, a manufacturing method thereof, and a vehicle air spring.

  Air springs installed and used as shock absorbers for railway vehicles generally have a top plate, a bottom plate, a substantially donut-shaped flexible member (also referred to as a diaphragm) having an inner diameter opened, and a lower portion of the bottom plate. An air chamber is provided that is connected to the laminated rubber support and can be deformed in the vertical and horizontal directions by the top plate, the bottom plate, and the flexible member, and is used by supplying compressed air to the air chamber. Is done. Compressed air is generally configured such that a laminated rubber support is formed in a cylindrical shape and an inner cylinder serves as an air passage and can be supplied to the air chamber through the inner cylinder. Such an air spring is interposed between the bolsterless carriage and the vehicle body so that the lower part of the laminated rubber support is attached to the upper part of the bolsterless carriage. Pressurized air is supplied from the compressor through the inner cylindrical portion of the laminated rubber support through the opening on the inner diameter side of the flexible member, the flexible member expands into a predetermined shape, and the upper and lower sides of the carriage are mainly deformed by the flexible member. Transmission of direction and horizontal vibrations to the vehicle body is buffered. It is also possible to adjust the inclination of the vehicle body by changing / adjusting the air pressure in the air chamber in the left and right directions in the vehicle traveling direction so as to travel without greatly reducing the speed during curve traveling.

  In such an air spring, a large horizontal displacement is generated in the flexible member that is a main part of the air spring during meandering and turning during vehicle travel, and the horizontal displacement causes the rubber layer on the outer peripheral surface of the flexible member to Sliding occurs on the contact surface between the upper surface plate holding this and the rubber portion of the lower surface plate, and wear occurs. When the rubber layer portion of the flexible member is worn, there is a problem that it is damaged early due to a large internal pressure, and a technique for preventing wear of the flexible member has been proposed to prevent such damage (Patent Documents 1 to 3). Such).

  The inventions described in Patent Documents 1 and 2 both prevent the rubber of the flexible member from being worn by disposing a resin sheet or fiber material having a small coefficient of friction between the top plate and the flexible member. It is. In addition, the invention described in Patent Document 3 uses ethylene propylene rubber (EPDM) as a raw material rubber constituting a flexible member in order to prevent wear due to sliding and to prevent a decrease in elasticity in a low temperature environment and an ozone deterioration. The invention is characterized in that it is used and polytetrafluoroethylene is blended therein.

  However, the inventions described in Patent Documents 1 and 2 can prevent wear between the upper surface plate and the flexible member, but cannot prevent wear of the flexible member due to sliding with the lower surface plate. In particular, the rubber seat on the bottom plate in contact with the flexible member has a small radius of curvature and a small surface area, so the pressure at the contact of the flexible member is large and a strong frictional force is generated. Easy to receive. Further, according to the invention described in Patent Document 3, although the coefficient of friction of the flexible member is reduced, EPDM is not so high in strength as rubber, and as a result of containing polytetrafluoroethylene, the strength is further reduced. Since wear occurs due to contact with the seat portion, there is still room for improvement in durability as an air spring.

A method of forming a lubricating layer by applying a commercially available polytetrafluoroethylene-containing paint or graphite-containing paint to the surface of a vulcanized rubber constituting the rubber seat portion of the lower surface plate and the upper surface rubber portion of the upper surface plate. However, if the lubrication layer is thin, it is not durable, but it is difficult to thicken the lubrication layer by coating, and the rubber after vulcanization such as buffing is used to improve the adhesion of the paint. There is a problem that the surface treatment needs to be performed and man-hours are required.

JP 2001-89549 A JP 2003-40967 A JP 2007-308656 A

  In view of the above-mentioned problems of the known technology, the present invention further improves the wear of a flexible member due to sliding with a rubber seat portion, and a bottom plate used for an air spring excellent in durability and a method for manufacturing the same. An object of the present invention is to provide an air spring with improved durability.

The lower surface plate for an air spring of the present invention is a lower surface plate for supporting a lower surface portion of a substantially donut-shaped flexible member having an inner diameter portion opened in a vehicle air spring,
The lower surface plate is composed of a lower surface annular support and a rubber seat bonded to the lower surface annular support,
Of the rubber seat portion divided in the longitudinal direction, a lubricating rubber portion containing polytetrafluoroethylene is formed on the outer diameter side of the lower surface annular support, and a poly rubber is formed on the inner diameter side of the lower surface annular support. A non-lubricating rubber part not containing tetrafluoroethylene is formed .

  By using the bottom plate having the above-described configuration, the life reduction due to wear of the flexible member due to sliding with the rubber seat portion is improved, and an air spring having excellent durability can be configured. Further, since it does not contain polytetrafluoroethylene, the strength and life of the flexible member itself are improved. Further, compared to the case where the rubber part is coated after vulcanization molding, processing such as buffing is unnecessary.

An air spring for a vehicle according to the present invention includes at least an upper surface plate, a lower surface plate, and a substantially donut-shaped flexible member having an inner diameter portion opened, and the opening portion of the flexible member is formed by the upper surface plate and the lower surface plate. A retained air spring for a vehicle,
The upper surface plate is composed of an upper surface annular support and an upper surface rubber portion bonded to the upper surface annular support, and the lower surface plate is the above-described lower surface plate for an air spring of the present invention,
At least a part of the upper rubber portion is a lubricating rubber portion containing polytetrafluoroethylene.

The air spring having the above structure is excellent in durability because the life of the flexible member due to wear of the flexible member due to sliding with the rubber seat portion of the lower surface plate and sliding with the upper surface rubber of the upper surface plate is improved. . Moreover, since it does not contain polytetrafluoroethylene, it is an air spring in which the strength and life of the flexible member itself are improved. Further, compared to the case where the rubber part is coated after vulcanization molding, processing such as buffing is unnecessary.

  Since the rubber constituting the rubber seat portion of the lower surface plate and the upper surface rubber portion of the upper surface plate of the present invention has no problem of weather resistance, particularly cracking due to ozone, unlike the rubber constituting the flexible member, EPDM and It is not necessary to use a rubber having excellent weather resistance such as polychloroprene but insufficient strength. The raw rubber constituting the rubber seat and the top rubber part is natural rubber alone, styrene butadiene rubber alone, natural rubber and styrene butadiene rubber, natural rubber and butadiene rubber, styrene butadiene rubber and butadiene rubber. It is preferable to select from a combination or a combination of natural rubber, styrene butadiene rubber and butadiene rubber. When natural rubber and styrene butadiene rubber are used together, natural rubber and butadiene rubber are used together, or natural rubber, styrene butadiene rubber and butadiene rubber are used together, the blending ratio of styrene butadiene rubber or butadiene rubber is 10 wt. Part or more. In the case of the combined use of natural rubber and butadiene rubber, or the combined use of styrene butadiene rubber and butadiene rubber, the ratio of butadiene rubber is preferably 10 to 50 parts by weight, and 10 to 30 parts by weight, per 100 parts by weight of the raw rubber. Is more preferable.

  The above rubber is excellent in wear resistance, and by adding polytetrafluoroethylene, while reducing the friction with the flexible member and reducing the wear of the rubber of the flexible member, Wear of the rubber seat portion and the upper surface rubber portion can also be suppressed.

  The amount of polytetrafluoroethylene added to the rubber constituting the rubber seat portion and the upper rubber portion is preferably 3 to 15 parts by weight with respect to 100 parts by weight of the raw rubber.

  If the amount of polytetrafluoroethylene blended is too large, the strength of the rubber may decrease, and conversely, wear of the rubber seat portion and the upper surface rubber portion may increase. When the blending amount of polytetrafluoroethylene is too small, the friction coefficient is not sufficiently lowered, and the wear of the flexible member is increased.

  A known additive can be blended with the rubber constituting the rubber seat portion and the upper rubber portion. Specifically, carbon black, silica and the like are exemplified as the reinforcing filler, and zinc oxide, stearic acid, metal stearate, wax and the like are exemplified as the processing aid, plasticizers such as process oil, anti-aging agent, Examples include inorganic fillers such as talc and calcium sulfate, vulcanizing agents, vulcanization accelerators, and the like. The vulcanized rubber constituting the rubber seat portion preferably has a hardness (durometer A hardness) of 45 to 60, and the vulcanized rubber constituting the upper rubber portion has a hardness (durometer A hardness) of 65 to 75. preferable.

  Polytetrafluoroethylene is added as a fine powder. Polytetrafluoroethylene is preferably blended together with low molecular weight polyethylene, and according to such a configuration, the dispersibility of polytetrafluoroethylene in the rubber material is improved, and favorable results such as improvement in rubber strength are obtained. The low molecular weight polyethylene used preferably has a melting point of 100 ° C. or higher and 140 ° C. or lower. It is preferable to mix polytetrafluoroethylene and low molecular weight polyethylene in advance for use in the production of the raw rubber composition. When premixed, polytetrafluoroethylene is 10 wt% to 50 wt% in the total amount. It is preferably 20% by weight or more.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal side view illustrating an air spring. The present invention is characterized by at least a rubber material constituting a rubber seat, but other configurations are the same as those of a conventional air spring. The air spring 10 includes an upper surface plate 16, a flexible member 18, and a lower surface plate 20, and supports a large deformation absorbing portion that absorbs large displacement and the large deformation absorbing portion, and supplies compressed air to the inside of the flexible member. It comprises a cylindrical laminated rubber support 24 having an air passage. The laminated rubber support 24 is formed by laminating and laminating a plurality of annular disks 26 and rubber layers 28, and has a vibration buffering action. A connection nozzle 29 is provided below the laminated rubber support 24 to send compressed air to the air chamber through the cylindrical portion.

  The flexible member 18 is substantially donut-shaped (substantially C-shaped in cross section) with an inner diameter portion opened, and has a shape and structure similar to a tire, and the end portions of the opening portions are outer surfaces on the upper surface side and the lower surface side, respectively. A convex upper surface bead portion 19a and a lower surface bead portion 19b are formed on the side, and bead wires (not shown) are arranged in the inner circumferential direction in the upper and lower bead portions 19a and 19b in the same manner as the tire. The flexible member 18 is formed of a vulcanized rubber film in which a textile cord is embedded as a reinforcing material, and the reinforcing material is arranged in a bias shape like the tire, and the end of the reinforcing material is wound around a bead wire. It has a structure. The bead portions 19a and 19b including the bead wires are fixed to the upper surface plate 16, the stopper receiving base 11, the lower surface plate 20 and the stopper 30, respectively, by a self-sealing method or a fastening method. The upper surface plate 16 includes an upper surface rubber portion 14 formed by adhesion on the contact side of the upper surface annular support 12 and at least the flexible member 18 of the upper surface annular support 12. The lower surface plate 20 is provided with a rubber seat portion formed on the contact side between the lower surface annular support 35 and at least the flexible member of the annular support.

  On the outer peripheral side of the upper surface plate 16, an inclined surface is formed which is inclined downward, that is, toward the flexible member. Further, the flexible member 18 is configured to be eccentric from the center surface of the upper and lower bead portions 19a and 19b, that is, toward the lower surface plate 20 side. With this configuration, when the flexible member receives an external force that deforms in the horizontal direction (front / rear / left / right direction), the inclined surface acts as a stopper, and a reaction force that counters the deformation is formed. The upper surface annular support 12 that constitutes the upper surface plate 16 may be flat so that only the upper surface rubber forms an inclined surface, and when an additional stopper is provided, the upper surface plate 16 may be flat. .

FIG. 2 illustrates an enlarged rubber seat portion of the bottom plate 20 of the present invention (however, the form (a) is not included in the present invention) . Lower plate 20a is an embodiment of good applicable, rubber seat portion is formed extends from the upper surface is the contact side of the flexible member 18 of the annular support 35 and annular support 35 to the outer end lower surface The rubber seat portion includes a non-lubricating rubber portion 33 and a lubricating rubber portion 31 formed in a film shape on the outer surface thereof, that is, on the surface in contact with the flexible member 18. The K portion is a portion where sliding with the flexible member is large. In the portion close to the inner diameter of the annular support 35, there is contact with the flexible member, but sliding is small. Therefore, it is preferable that the lubricating rubber portion 31 is formed so as to include a portion K, that is, at least a portion K that is strongly slid with the flexible member, or may be formed only in the portion K.

  The thickness of the lubricating rubber portion 31 formed in a film shape is preferably 0.3 mm or more, and more preferably 1 mm or more. If the film-like lubricating rubber part is too thin, the polytetrafluoroethylene-containing layer may wear out, causing wear of the flexible member due to sliding, In manufacturing the upper surface plate and the lower surface plate, when the unvulcanized lubricating rubber raw material composition is made into a single sheet, it is necessary to process it thinly, which makes the processing difficult.

  The bottom plate 20b shown in FIG. 2B has the same shape as the bottom plate 20a, but the non-lubricating rubber portion 33 is on the inner diameter side of the bottom annular support 35, and the lubricating rubber portion 31 is a rubber seat. It is divided in the vertical direction and formed on the outer diameter side. As described above, the lubricating rubber portion 31 is formed to include a K portion where sliding with the flexible member occurs.

FIG. 3 is an enlarged cross-sectional view of the top plate 16 of the air spring illustrated in FIG. The upper surface plate 16 has an upper surface annular support member 12 and an upper surface rubber portion 16 bonded to the upper surface annular support member 12 in the same manner as the lower surface plate. The upper surface rubber portion 16 is composed of the non-lubricated rubber portion 14 and its flexible member 18. And a lubricating rubber portion 15 formed on the surface side in contact with the.

FIG. 4 is a partially longitudinal side view showing another embodiment of the air spring using the upper surface plate or the lower surface plate of the present invention. In the air spring 40 of this embodiment, the structure of the upper surface annular support 42 that constitutes the upper surface plate is configured to be a structure in which the annular body at the center is integrated. Further, the cross section of the bottom plate 48 is formed in an S-shape and the width is narrower than that in the example of FIG. 1, and a steel ring 57 is disposed in contact with the bottom annular support 35 for reinforcement. .

FIG. 5 is a cross-sectional view illustrating the structure of the rubber seat portion of the bottom plate 48 shown in FIG. 4 (however, the form (a) is not included in the present invention) . The rubber seat shown in FIG. 5A includes a lower surface annular support 55, a non-lubricated rubber portion 53 on the steel ring 57 side fixedly disposed on the upper surface thereof, and a lubricating rubber portion 51 covering the outer peripheral surface of the non-lubricated rubber portion. The rubber seat portion of FIG. 5 (b) has a lubricating rubber portion 51 on the outer peripheral side of a reinforcing member comprising a lower ring support 55 and a steel ring 57 fixedly disposed on the upper surface thereof, and A non-lubricated rubber portion 53 is formed on the inner peripheral side.

  The lubricating rubber layer is preferably provided on the rubber seat portion of the lower surface plate or both the lower surface plate and the upper surface rubber portion of the upper surface plate, and when provided only on the rubber seat portion, Patent Document 1 is provided between the upper surface plate and the flexible member. A sliding sheet having a low coefficient of friction may be provided as described in.

  The lower surface annular support constituting the lower surface plate and the upper surface annular support constituting the upper surface plate are formed of a highly rigid material. As such a highly rigid material, a steel plate, a stainless steel plate, a fiber reinforced resin, or the like can be used, but it is preferable to use a steel plate. The method for adhering the upper and lower annular supports and the vulcanized rubber is not particularly limited. Usually, an unvulcanized rubber is disposed on the support after the adhesive and the adhesive have been applied, and then pressurized in the mold. Vulcanization adhesion is performed in which the vulcanized rubber part is formed by vulcanization and bonded at the same time.

A method for manufacturing the upper surface plate and the lower surface plate having the lubricating rubber layer will be described. The non-lubricating rubber raw material composition constituting the non-lubricating rubber layer and the lubricating rubber raw material composition constituting the lubricating rubber layer are respectively prepared by known methods. That is, among the raw materials constituting the lubricating rubber raw material composition and the non-lubricating rubber raw material composition, the components excluding the vulcanizing agent and the vulcanization accelerator are generally kneaded using a Banbury mixer to form a master batch, After the master batch is cooled, the master batch, the vulcanizing agent and the vulcanization accelerator are kneaded using a kneader or a kneading roll, and a reaction curable raw material composition is obtained which is vulcanized by heating. The reaction curable raw rubber composition is molded into a shape suitable for molding using an extruder or the like, and used for manufacturing the upper surface plate and the lower surface plate. Specifically, it is formed into a continuous flat sheet using an extruder, cut into an appropriate length, stacked as necessary, and laminated on an annular support, for example, the cross section of FIG. A method of heating and pressurizing in a mold after forming a shape close to the shape, using a die whose cross section is, for example, FIG. Examples thereof include a method of bonding to an annular support after extrusion and heating and pressurizing in a mold. At this time, the raw rubber constituting the lubricating layer may be separately formed into a sheet shape and laminated at the time of molding, or two extruders may be connected to one die and the raw rubber composition of the first extruder The non-lubricated rubber raw material composition may be supplied to the second extruder and extruded into a predetermined two-layer structure to form a top plate and a bottom plate. It is also possible to use a strip build method in which thin ribbon-like raw rubber compositions are extruded and stacked to form a predetermined shape.

  The lubricating rubber contains polytetrafluoroethylene fine powder as a component. Further, as described above, it is preferable to knead the polytetrafluoroethylene in a state of being mixed with low molecular weight polyethylene. In kneading a raw rubber composition containing a mixture of polytetrafluoroethylene and low molecular weight polyethylene that is vulcanized and cured by heating, the temperature of the kneaded rubber should not exceed the melting point of the low molecular weight polyethylene. It is preferable from the viewpoint of uniform dispersion of fluorinated ethylene. The vulcanization temperature for vulcanizing and curing the raw rubber composition is preferably 140 ° C. or higher.

In the case of performing vulcanization adhesion, a vulcanization adhesive is applied to the rubber portion forming portion as necessary on the annular support member constituting the upper surface plate and the annular support member constituting the lower surface plate. In the case of a metal material such as a steel plate or stainless steel, shot blasting is performed in advance, and then a vulcanized adhesive is applied.

[Preparation of lubricating rubber raw material composition]
Example 1
100 parts by weight of natural rubber, 15 parts by weight of aromatic process oil, 30 parts by weight of FEF carbon black, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1 part by weight of paraffin wax, 2 parts by weight of antioxidant, polytetrafluoride A master batch obtained by kneading 10 parts by weight of a mixture of ethylene and low molecular weight polyethylene (polytetrafluoroethylene content 40% by weight) with a Banbury mixer so that the temperature of the kneaded product becomes 120 ° C. After the batch was cooled to room temperature, 3 parts by weight of sulfur and 0.8 part by weight of a sulfenamide vulcanization accelerator were added and kneaded with respect to the total amount of the master batch using a kneader to obtain a lubricating rubber raw material composition.

(Example 2)
A lubricating rubber raw material composition was prepared by the same composition and method as in Example 1 except that 100 parts by weight of styrene butadiene rubber was used as the raw rubber.

(Example 3)
A lubricating rubber raw material composition was prepared by the same blending composition and method as in Example 1 except that 80 parts by weight of natural rubber and 20 parts by weight of butadiene rubber were used as the raw rubber.

Example 4
A lubricating rubber raw material composition was prepared by the same blending composition and method as in Example 1 except that 80 parts by weight of natural rubber and 20 parts by weight of styrene butadiene rubber were used as the raw material rubber.

[Preparation of raw material composition of non-lubricating rubber]
The non-lubricating rubber raw material composition constituting the rubber seat portion of the example and the non-lubricating rubber portion of the upper rubber portion and the rubber seat portion and the upper rubber portion of the comparative example were prepared as follows. 100 parts by weight of natural rubber, 15 parts by weight of aroma-based process oil, 30 parts by weight of FEF carbon black, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1 part by weight of paraffin wax, 2 parts by weight of anti-aging agent in a Banbury mixer Knead to make a master batch, and after cooling the resulting master batch to room temperature, add 3 parts by weight of sulfur and 0.8 parts by weight of sulfenamide vulcanization accelerator to the total amount of the master batch using a kneader. It knead | mixed and it was set as the non-lubricated rubber raw material composition.

(Flexible member)
The flexible member was manufactured by a known method. That is, a nylon cord was topped, and a rubber raw material composition was topped using a calendar roll to obtain a topping cord, which was cut by a cutter so that the cord forms a predetermined angle and used for molding. In molding, topping cords are laminated as necessary, and after placing beads at the ends, the topping cords are folded back so as to wrap the beads, and rubber members are attached to the surface layer and the inner layer to form an unvulcanized molded product. Press molding in the mold. The composition of the raw material rubber composition of the flexible member is as follows.
Polychloroprene rubber 70 parts natural rubber 30 parts FEF carbon black 30 parts aroma-based process oil 10 parts zinc oxide 5 parts stearic acid 1 part paraffin wax 2 parts fatty acid ester (Exton K-1) 3 parts by weight Sulfur 2 parts by weight Thiazole vulcanization accelerator 1 part by weight Thiuram vulcanization accelerator 0.5 part by weight

(Preparation of rubber material for molding rubber seat part and rubber material for molding upper surface rubber part)
The lubricating rubber composition for molding was prepared by forming the above-mentioned unvulcanized rubber composition into a sheet with a roll and laminating the respective sheets to form a molding material. The non-lubricating rubber composition is formed into a sheet so as to have a necessary thickness, and the sheet-like lubricating rubber composition and the non-lubricating rubber composition are laminated to form a molding rubber material suitable for molding. And used for the manufacture of the top and bottom plates.

(Manufacture of bottom plate)
A commercially available vulcanized adhesive was applied after shot blasting both surfaces of an iron bottom annular support member having the cross-sectional shape shown in FIGS. A non-lubricated rubber raw material composition and a lubricating rubber raw material composition are bonded to a bottom annular support member coated with a vulcanized adhesive, and heated and pressed at 160 ° C. in a mold to form an unvulcanized rubber. Was vulcanized and molded into a predetermined shape to produce a bottom plate.

(Manufacture of top plate)
As shown in FIG. 3, an upper surface plate having an upper surface rubber portion on which a lubricating layer having a thickness of about 2 mm was formed on the surface was manufactured by the same method as the manufacture of the lower surface plate.

About the lubricating rubber raw material composition of Examples 1-4, the sheet-like vulcanized rubber of thickness 2mm was created.

(Evaluation)
(1) Durability test of air spring The air spring was set in the same state as in actual use, an internal pressure of 500 kPa was applied at a temperature of 25 ° C., and vertical vibration was repeatedly applied 1 million times and horizontal vibration was repeated 200,000 times. Later, the wear of the rubber seat surface and the top rubber surface was evaluated. The evaluation results are shown in (Table 1). The vibration was performed with an amplitude of ± 30 mm in the vertical direction and a vibration frequency of 1.0 Hz, and an amplitude of ± 75 mm in the horizontal direction and a vibration frequency of 0.5 Hz.
(2) Taber abrasion A rubber / rubber abrasion test was conducted. Cut the flexible material sheet into a disk and set it on the rotating plate of the Taber Abrasion Tester. Create two wear wheels with lubricated rubber and non-lubricated rubber and attach the left and right wear wheels of the Taber Abrasion Tester. Set on the arm. The abrasion test was performed at a load of 500 g in accordance with JIS K 6264. The results are shown in Table 3 by measuring the wear amount (× 10 ⁻³ cc) of the rubber of the wear wheel and the sheet-like rubber after 2000 times wear.
(3) Finger touch evaluation The degree of adhesion was evaluated by finger touching the surface of the wear wheel constituting rubber after the Taber abrasion test. The degree of adhesion is a performance that can be easily evaluated by finger touch. The results are shown in Table 2.

  Table 1 shows the durability test results of the air spring. From the results of Table 1, the air spring using the lower surface plate having the rubber seat portion having the lubricating rubber portion of the present invention and the upper surface plate having the upper surface rubber portion having the lubricating rubber portion is the wear resistance of the flexible member. As a result, it can be seen that the durability is improved. The evaluation results of the Taber abrasion shown in Table 3 also confirm the durability test results when the lubricating rubber of the present invention is used, and the rubber wear of both the rubber seat and the flexible member is reduced. It is.

  Table 1 shows the results of manufacturing and evaluating an air spring using the lubricating rubber of Example 2 for the upper rubber part of the upper surface plate and the lubricating rubber part of the rubber seat portion of the lower surface plate. Table 2 shows the results of finger touch evaluation on the lubricating rubbers ˜4. It can be seen that all have superior lubricity as compared with the rubber of the comparative example not containing polytetrafluoroethylene. Therefore, even when the lubricating rubbers of Examples 1, 3, and 4 are used, it is presumed that the air spring has excellent durability.

A longitudinal side view illustrating an air spring using the bottom plate of the present invention The fragmentary sectional view which shows suitable embodiment of the structure of the lower surface board of this invention (however, the form of (a) is not included in this invention) The fragmentary sectional view which shows suitable embodiment of the structure of the upper surface board of this invention The fragmentary sectional view which shows another suitable embodiment of the structure of the lower surface board of this invention Partial cross-sectional view showing an enlarged rubber seat portion of the lower surface plate shown in FIG. 4 (however, the form of (a) is not included in the present invention)

DESCRIPTION OF SYMBOLS 10 Air spring 16 Lower surface board 18 Flexible member 31 Lubricating rubber part 35 Lower surface annular support body

Claims (5)

In a vehicle air spring, a bottom plate that supports a bottom surface of a substantially donut-shaped flexible member having an inner diameter opened,
The lower surface plate is composed of a lower surface annular support and a rubber seat bonded to the lower surface annular support,
Of the rubber seat portion divided in the longitudinal direction, a lubricating rubber portion containing polytetrafluoroethylene is formed on the outer diameter side of the lower surface annular support, and a poly rubber is formed on the inner diameter side of the lower surface annular support. A bottom plate for an air spring in which a non-lubricated rubber portion not containing tetrafluoroethylene is formed .   2. The lower part for an air spring according to claim 1, wherein the raw rubber constituting the lubricating rubber part is any one of natural rubber, styrene butadiene rubber, natural rubber and styrene butadiene rubber and / or butadiene rubber, styrene butadiene rubber and butadiene rubber. Face plate. 2. The lubricating rubber portion is formed on an outer peripheral side of a reinforcing member made of a steel ring fixedly disposed on the lower surface annular support and the upper surface thereof, and the non-lubricating rubber portion is formed on an inner peripheral side. Or the lower surface board for air springs of 2. Vehicular air including a structure including at least an upper surface plate, a lower surface plate, and a substantially donut-shaped flexible member having an inner diameter portion opened, the opening portion of the flexible member being held by the upper surface plate and the lower surface plate A spring,
The upper surface plate includes an upper surface annular support and an upper surface rubber portion bonded to the upper surface annular support, and the lower surface plate is the lower surface plate for an air spring according to any one of claims 1 to 3.
Is at least partially lubricated rubber portion containing polytetrafluoroethylene air spring for a vehicle before Symbol top rubber portion. In a vehicle air spring, a method of manufacturing a lower surface plate for supporting a lower surface portion of a substantially donut-shaped flexible member having an inner diameter portion opened,
The lower surface plate is composed of a lower surface annular support and a rubber seat bonded to the lower surface annular support,
Of the rubber seat portion divided in the longitudinal direction, a lubricating rubber portion containing polytetrafluoroethylene is formed on the outer diameter side of the lower surface annular support, and a poly rubber is formed on the inner diameter side of the lower surface annular support. A non-lubricating rubber part not containing tetrafluoroethylene is formed,
An air spring in which a lubricating rubber raw material composition forming the lubricating rubber portion and a non-lubricating rubber raw material composition forming the non-lubricating rubber portion are disposed on the lower annular support and heated and vulcanized in a mold. Method for manufacturing the lower surface plate.

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