JP2649255B2 - Manufacturing method of centering bush - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a centering bush used for connecting a propeller shaft and an output shaft of a transmission in a drive system of an automobile or the like.

[Conventional technology]

2. Description of the Related Art Conventionally, in a drive system of an automobile, a connection between a propeller shaft and an output shaft of a transmission is provided with a flexible coupling or a tilger (dynamic) so that torsional vibration generated on the propeller shaft side is not transmitted to the output shaft side. In addition to installing a vibration absorber), the third purpose is to suppress mutual runout of the propeller shaft and output shaft.
A centering bush as shown in the figure is mounted.

In FIG. 3, reference numeral (1) denotes an outer sleeve fixed to the propeller shaft side, and (2) denotes an inner sleeve slidably inserted on the output shaft of the transmission. ) Is positioned coaxially, and an elastic body (3) is interposed between the sleeves (1) and (2), and is adhered to the sleeves (1) and (2). The bush is filled with grease (not shown) in order to smoothly slide the output shaft and the inner sleeve (2), and a cap (4) is provided at the tip end of the output shaft to seal the grease. , A seal lip (5) is provided on the base side. This seal lip (5) also has a function of preventing dust from entering the sliding portion, and is formed integrally with the elastic body (3), and its base (5a) is formed of an inner sleeve (2). ) In the axial direction (2a).

In manufacturing the centering bush, the outer sleeve (1) and the inner sleeve (2) are formed in advance, and then these two sleeves (1) and (2) are put into a cavity of a rubber molding die and molded. The material is vulcanized to form the elastic body (3) and the seal lip (5) integrally. The base (5a) of the seal lip (5) is formed at the end (2a) of the inner sleeve (2) as described above during this molding.
However, in this molding, the sealing edge (5b, see FIG. 4) of the seal lip (5) should be prevented from wrapping around the inner diameter surface (2b) serving as the sliding surface of the inner sleeve (2). You have to be careful.

Conventionally, in order to prevent the molding material from wrapping around, means for strongly pressing the mold against the inner sleeve (2) when incorporating the inner sleeve (2) into the mold has been adopted. That is, a portion (2c) of the end (2a) of the inner sleeve (2) that is exposed to the outside without being covered with rubber after molding.
The mold in contact with the portion (2c) is strongly pressed to the portion near the inner diameter to prevent the molding material from entering between the mold and this portion (2c).

[Problems to be solved by the invention]

Since the inner sleeve (2) is in sliding contact with the output shaft of the transmission, the inner sleeve (2) is often molded from a resin having excellent lubricity such as polyacetal resin. When the mold is strongly pressed against the end (2c portion of 2a) as described above, the entire end (2a) is deformed as shown by a broken line in FIG. Since a gap is generated between the bonding surfaces after molding, the rubber material may be peeled off and adversely affect the operation.

The present invention has been made in view of the above points, and has as its object to prevent a base of a seal lip from peeling off from an inner sleeve.

[Means for solving the problem]

In order to achieve the above object, a manufacturing method of the present invention provides a centering bush in which a rubber sealing lip (5) is vulcanized and bonded to an axial end (2a) of an inner sleeve (2). End of (2) (2a)
The inner sleeve (2) is placed in a mold for molding the seal lip (5) in advance, and a portion (2e) of the end portion (2a) located on the inner diameter side of the annular recess is formed of metal. The sealing recess is filled with a part of the sealing lip (5) molding material to form an adhesive edge (5b) of the sealing lip (5).

(Operation)

When the inner sleeve (2) having the annular concave portion is assembled into a mold and the inner diameter side of the end (2a) is pressed by the mold, the end (2a) is annularly deformed without being deformed on the entire surface. It has been confirmed by experiments conducted by the inventors that the large deformation occurs only on the inner diameter side, which is the directly pressed portion, with the concave portion as a boundary, and the deformation on the outer diameter side is hardly affected. The present invention focuses on this point, and suppresses deformation of a portion of the end (2a) of the inner sleeve (2) to which the seal lip (5) is bonded, thereby preventing the rubber material from peeling off at the portion.

〔Example〕

Next, an embodiment of the present invention will be described with reference to FIG. 1 which illustrates a main part of a centering bush manufactured by the method. The structure of the other parts not shown in the figure is the same as that of the prior art shown in FIG. 3, and the description thereof is omitted.

An annular recess (2d) having a substantially triangular cross section is formed in advance at an end (2a) of the inner sleeve (2) formed of a resin material such as the polyacetal resin, and the inner sleeve (2) is formed of a metal outer sleeve ( Along with 1), the mold is put into the cavity of the mold, and the mold in contact with the portion (2e) of the end (2a), which is located on the inner diameter side from the annular concave portion (2d), is strongly pressed. In this state, heat is applied to vulcanize the molding material of the seal lip (5), and a part thereof is filled into the annular concave portion (2d) to form an adhesive edge (5b) of the seal lip (5). I do. The end (2a) of the inner sleeve (2) is deformed by being strongly pressed by the mold, but this deformation is stopped only at the portion (2e) on the inner diameter side directly pressed by the annular recess (2d). The portion (2f) on the outer diameter side is hardly deformed, so that peeling of the seal lip (5) can be prevented. Annular recess (2d)
Since the molding material filled therein adheres to the inner wall of the concave portion (2d) in a wide area, the adhesive force of this portion (that is, the adhesive edge (5b)) is also increased as compared with the related art. Various shapes such as a semicircular shape as shown in FIG. 2 are conceivable for the sectional shape of the annular concave portion (2d), and the shape is not particularly limited.

〔The invention's effect〕

As described above, the manufacturing method of the centering bush of the present invention forms an annular concave portion at the axial end of the inner sleeve to prevent deformation of the inner sleeve due to pressing of the mold during molding of the seal lip except for the seal lip bonding portion. The bush product excellent in operability and durability can be provided by effectively preventing the peeling phenomenon of the seal lip.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a centering bush manufactured by a method according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part showing another example of the centering bush, and FIG. FIG. 4 is an enlarged sectional view of a main part of FIG. (1) ... outer sleeve, (2) ... inner sleeve (2a) ... axial end, (2b) ... inner diameter surface, (2d) ...
Annular recess (2e) ... inner diameter part, (2f) ... outer diameter part, (3) ...
Elastic body (4) Cap, (5) Seal lip (5a) Base, (5b) Adhesive edge

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 31:24

Claims (1)

(57) [Claims] An axial end (2) of an inner sleeve (2).
In the centering bush in which a rubber sealing lip (5) is vulcanized and bonded to a), an annular concave portion (2d) is previously formed at an end (2a) of the inner sleeve (2), and the inner sleeve (2) is formed. Seal lip (5)
The mold is placed in a molding die, and a portion (2e) of the end (2a) located on the inner diameter side of the annular recess (2d) is pressed by a mold, and a seal lip (5) is formed in the annular recess (2d). A method for manufacturing a centering bush, characterized in that a part of the material is filled to form an adhesive edge (5b) of a sealing lip (5).