JPH04168030A - Manufacture of duct cover - Google Patents

Abstract

PURPOSE:To make it possible to form a first ring part, the height of which is nearly the same as the interval between an arm and the flange of a retainer, by a method wherein parison is supplied between a pair of blow molds and, by clamping the blow molds, a core and a center core mold, some part of the parison is compressed so as to shape the first ring part of the parison and then, by supplying air in the interior of the parison, the parison is pressed so as to be shaped into the belly part of the dust cover concerned and finally cooled and solidified. CONSTITUTION:Under the condition that parison 33 is supplied between body blow molds 24 and 25, both the blow molds 24 and 25 are clamped together and the respective under faces of a die 26 and of a core main body 28 are slid in the order named and a center core mold 30 is raised. Thus, the parison 33 is compressed among tire forming recess 37 of the core main body 28, the inner face 24a of the blow mold 24, the forming recess 38 of an annular projection 34, a forming projection 39 and the outer peripheral surface 29a of an engaging projection 29 so as to shape a first ring part 12. Next, by supplying compressed air A through passages 35 and 36, the parison 33 is expanded and pressed against the forming recesses 31 of the blow molds 24 and 25 so as to be shaped into the belly part 11 and a second ring part 13. In succession, the parison 33 is cooled and solidified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of manufacturing a dust cover that is attached to, for example, a ball joint of a suspension system to prevent dust from entering the ball joint. It is something.

[Prior Art] Conventionally, for example, in a suspension system for an automobile, a ball joint 53 is used to connect a knuckle arm 51 and a lower arm 52, as shown in FIG. The ball joint 53 includes a pole stud 54 consisting of a shaft portion 55 and a spherical portion 56. The shaft portion 55 is fixed to the knuckle arm 51, and the spherical portion 56 is accommodated in a socket 57 of the lower arm 52. Note that a retainer 58 is fixed to the outer periphery of the shaft portion 55 directly below the knuckle arm 51.

The pole joint 53 is covered by a dust cover 59. This dust cover 59 includes an abdomen 60 and first and second ring parts 61.6 provided at both upper and lower ends of the abdomen 60.
It is composed of 2.

The second ring portion 62 is tightened and fixed to the socket 57, and the first ring portion 61 is fitted onto the retainer 58 so as not to rotate together when the knuckle arm 51 swings and rotates.

Incidentally, the dust cover 59 is manufactured by blow molding. That is, first, as shown in FIG. 8, a parison 65 is supplied between a pair of opened blow molds 63 and 64. Subsequently, as shown in FIG. 9, by clamping the blow molds 63 and 64, a part of the parison 65 is compressed between the core 66 and the first ring portion 61.
Shape into.

Furthermore, by supplying compressed air A inside the parison 65, the parison 65 is expanded to form a blow mold 63.6.
4 to form the abdomen 60 and the second ring part 62. Then, the shaped parison 65 is cooled and solidified.

[Problems to be Solved by the Invention] In the ball joint 53 and the dust cover 59, the knuckle arm 51 and the first ring portion 6 are arranged in order to prevent dust and the like from entering into the dust cover 59.
1 and between the flange 58a of the retainer 58 and the first ring portion 61. For this purpose, the height of the first ring portion 61 must be set so that the height of the knuckle arm 5 is
1 and the flange 58a, the dust cover 59 must be formed with high precision so that the distance between the dust cover 59 and the flange 58a is approximately the same.

However, in the conventional manufacturing method, when the blow mold 63, 64 is clamped as shown in FIGS. , it flows and drips as shown by the arrow. This sag occurs because the first ring portion 61 has a small diameter and the parison 65 is compressed. Then, a lump of flesh 67 is formed due to this dripping.

Therefore, when the dust cover 59 formed as described above is attached to the hole joint 53, the first ring portion 61 is deformed between the knuckle arm 51 and the flange 58a, as shown in FIG.

Therefore, the knuckle arm 5■ and the first ring portion 61
It has been difficult to reliably seal between the flange 58a of the retainer 58 and the first ring portion 61.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent the formation of lumps in the first ring part and to make the height of the first ring part such that the height of the arm and the retainer are equal to each other. It is an object of the present invention to provide a manufacturing method capable of forming a dust cover so that the distance between the dust cover and the flange is approximately the same.

[Means for Solving the Problem] In order to achieve the above object, the present invention includes a hollow abdomen 4 portion, first and second link portions formed at both ends of the abdomen, and a hole stud. A method of manufacturing a dust cover in which the first ring part is interposed between an arm fixed to a pole stud and a flange of a retainer fixed to a shaft part of the pole stud, the method comprising: a pair of opened molds; A step of supplying a parison between blow molds, compressing a part of the parison by clamping the blow mold, a core, and a core mold having a protrusion for preventing drooping, and compressing a part of the parison with the protrusion. The parison is expanded and blown by forming the same material into the first ring part while preventing the bottom of the first ring part from sagging, and by supplying air into the inside of the parison. The gist thereof is a method for manufacturing a dust cover, which includes a step of pressing it into a mold and shaping it into the abdomen, and a step of cooling and solidifying the shaped parison.

[Operation] To manufacture a dust cover, first, a pair of blow molds are opened, and a parison is supplied between the two blow molds. Next, the blow mold, the core, and the core mold having a protrusion for preventing sag are clamped together to compress a portion of the parison. Then, the parison is shaped into the first ring part with the core-shaped protrusion preventing the bottom of the first ring part from sagging.

Subsequently, air is supplied inside the parison.

By this supply, the parison is expanded and pressed into a blow mold, and is shaped into the abdomen. After the parison is shaped into a predetermined shape as described above, it is cooled and solidified.

The first ring portion of the dust cover manufactured in this manner has no buildup, and therefore the height of the first ring portion is approximately the same as the distance between the arm and the flange of the retainer. It is possible.

[Example] An example embodying the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a sectional view of a pole joint 3 that connects a knuckle arm 1 and a lower arm 2 in an automobile suspension system. The hole joint 3 includes a hole stud 4 consisting of a shaft portion 5 and a spherical portion 6. The shaft portion 5 is fixed to the knuckle arm 1 by a bolt 7. Further, the spherical portion 6 is loosely fitted into a socket 8 at the end of the lower arm 2.

The spherical portion 6 is urged toward the knuckle arm 1 by a sublink 9 housed in a socket 8.

A dust cover 10 is installed between the knuckle arm 1 and the socket 8 so as to partially cover the pole stud 4, and the dust cover 10 and the socket 8 are filled with grease. The dust cover 10 is composed of a bellows-shaped abdomen 11, a first ring part 12 provided at the upper end of the bellows-shaped abdomen 11, and a second ring part 13 provided at the lower end of the abdomen 11, and is made entirely of synthetic resin. It is integrally formed. The second link portion 13 is externally fitted into a ring groove 14 at the upper end of the socket 8, and is tightened and fixed by a wire 15.

On the other hand, the first ring portion 12 of the dust cover 10 is attached to the shaft portion 5. That is, a retainer 16 is attached to the outer periphery of the shaft portion 5 of the pole stud 4 directly below the knuckle arm 1. The retainer 16 is composed of a cylindrical portion 17 that is caulked and fixed to the shaft portion 5, and a flange 18 that is bent at the lower end of the cylindrical portion 17 and parallel to the lower surface of the knuckle arm 1. And cylindrical part 1
A first ring portion 12 is fitted around the outer periphery of 7.

A plurality of sealing protrusions 19 and 20 are integrally formed on the upper and lower surfaces of the first ring portion 12 over the entire circumference. Each of the protrusions 19, 20 has a mountain-shaped cross section with a narrow end width. The height H of the first ring portion 12 having such projections 19 and 20 is approximately the same as the distance between the knuckle arm 1 and the flange 18.

Therefore, the first ring portion 12 is connected to the cylindrical portion 1 of the retainer 16.
7, the upper protrusion 19 abuts against the lower surface of the knuckle arm l, and the lower protrusion 20 abuts against the flange 18, thereby preventing water, muddy water, dust, etc. from entering into the dust cover 10. is being prevented.

An annular groove 22 is formed on the lower side of the boundary between the first link part 12 and the abdomen 11, and the annular groove 22 makes the boundary part thinner. The reason for making it thin like this is as follows. In other words, when the ball stud 4 swings integrally with the knuckle arm 1 and one side of the abdomen 11 contracts and the other side expands, if the boundary part is thick, the first link part will move along with the expansion and contraction. 12 or abdomen is pulled towards 11 side. As a result, the ability of the first ring portion 12 to follow the swinging motion of the pole stud 4 deteriorates, and the first ring portion 12 separates from the cylindrical portion 17 of the retainer 16.

For this reason, the boundary portion is made thinner and the first ring portion 12
This improves followability.

Next, a molding device used to manufacture the dust cover 10 will be explained. As shown in FIG. 2, this molding device 23 includes a pair of blow molds 24, 25, a die 26, a core 2
7 and a central core mold 30.

Both blow type 24. , 25 are movable in the left-right direction, and the die 26, core 27, and core mold 3° are movable in the vertical direction, and mold clamping and mold opening are performed by these movements. It has become.

A dust cover 10 is provided on the opposite surface of each blow mold 24, 25.
A molding recess 31 is provided for forming the outer surface shape of. Further, the core 27 disposed within the die 26 includes a core body 28 and an engaging protrusion 29 protruding from the lower surface of the core body 28.

A flow path 32 through which the molding material can pass is formed between the core body 28 and the die 26, and the parison 33 extruded from the flow path 32 passes through the pair of blow molds 24, 25.
It is supplied between. The wall thickness of the parison 33 at this time can be adjusted by moving the core body 28 vertically relative to the die 26 to change the flow path area.

The core mold 30 has a rod shape with a slightly smaller diameter than the parison 33 that is extruded from the flow path 32.

An annular protrusion 34 for preventing drooping is formed on the upper part of the core mold 30, and this annular protrusion 34 engages the engagement protrusion 29 of the core 27.
It can be fitted to In the core 27 and the core mold 30, passages 35 and 36 are provided through which the compressed air A can pass. When the engagement protrusion 29 and the annular protrusion 34 are combined, both the passages 35 and 36 communicate with each other, and the compressed air A is blown out toward the parison 33 (see FIG. 3).

By the way, the engagement protrusion 29 on the lower surface of the core body 28
A molding recess 37 for forming the protrusion 19 on the upper surface of the first ring portion 12 is provided around the periphery. Similarly, the upper surface of the annular projection 34 is provided with a molded recess 38 for forming the projection 20 on the lower surface of the first ring portion 12 and a molded projection 39 for forming the annular groove 22. There is.

Next, a method for manufacturing the dust cover 10 using the molding device 23 will be described.

First, as shown in FIG. 2, the core mold 30 is moved down and the supply of compressed air A to both passages 35 and 36 is stopped. Then, the pair of blow molds 24 and 25 are opened, and in this state, the parison 33 is supplied from the flow path 32 between the two blow molds 24 and 25.

Subsequently, as shown in FIG. 3, both blow molds 24 and 25 are clamped. Then, both blow molds 24 and 25 slide on the lower surfaces of the die 26 and the core body 28 in order, closing the flow path 32 and cutting off the supply of the parison 33. By sliding these blow molds 24.25, the parison 33 is sandwiched between the blow molds 24.25 and the engagement protrusion 29.

After both blow molds 24 and 25 are clamped, the core mold 30 is raised. In this embodiment, an annular projection 34 is provided on the upper part of the core mold 30, and molding recesses 37, 38 and a molding projection 39 are formed on the lower surface of the core body 28 and the upper surface of the annular projection 34. Therefore, when the core mold 30 is raised as described above, the annular protrusion 34 of the core mold 30 contacts the engagement protrusion 29 of the core 27.
are connected, and both passages 35 and 36 communicate with each other. As shown in FIG. The first ring part 12 is compressed between the first ring part 12 and the first ring part 12 having a protrusion 19,20 and an annular groove 22. At this time, the annular protrusion 34 prevents the bottom of the first ring portion 12 from sagging.

Next, as shown in FIG.
is supplied and blown out toward the parison 33.

As a result, the parison 33 expands and the blow mold 24.2
5 into the molding recess 31, and is shaped into the abdomen 11 and the second ring part 13.

Subsequently, the supply of compressed air A is stopped, and the parison 33 shaped into the first ring part 12, abdomen 11, and second ring part 13 is cooled and solidified. Then, an intermediate molded product 40 of the dust cover 10 as shown in FIG. 5 is molded.

After the intermediate molded product 40 is molded, the die 26 and the core 27
is moved upward, the core mold 30 is moved downward, and both blow molds 24 and 25 are moved left and right to open the mold. At this time, since the protrusions 19 and 20 have a triangular cross section,
The same protrusion 19.20 will not result in an undercut.

In the above state, since the intermediate molded product 40 covers the core mold 30, air is blown from below the core mold 30 to remove the intermediate molded product 40 from the core mold 30.

Since an unnecessary portion 41 is still formed at the lower end of the intermediate molded product 40 taken out from the core mold 30, the unnecessary portion 41 is cut off as shown in FIG.

Then, the desired dust cover 10 is obtained.

In the manufacturing process, when the parison 33 is shaped into the first link portion 12, the annular protrusion 34 receives and stops the parison 33 from below, which tends to sag due to compression. Therefore, the annular protrusion 34 prevents the formation of a lump of flesh due to the parison 33 sagging.

In the dust cover 10 of this embodiment manufactured as described above, the first link portion 12 has the shape as designed, that is, there is no lump of flesh, and the protrusions 19 and 20 having a chevron-shaped cross section are formed on the upper and lower surfaces. It is formed into a shape that has. The height H of the first ring portion 12 is approximately the same as the distance between the knuckle arm 1 and the flange 18 of the retainer 16, as shown in FIG. Therefore, when the dust cover 10 is attached to the ball joint 3, the protrusions 19 and 20 of the first ring portion 12 come into contact with the knuckle arm l and the flange 18 of the retainer 16, and the dust cover 10 and the pole stud 4 come into contact with each other. is securely sealed.

It should be noted that the present invention is not limited to the configuration of the embodiments described above, and may be modified as desired without departing from the spirit of the invention, for example, as described below.

(1) The protrusion 19.20 of the first link portion 12 may be changed to have a semicircular cross section, or the protrusion 19.20 may be omitted.

(2) In the above embodiment, after removing the intermediate molded product 40 from the core mold 30, the unnecessary portion 41 was cut off, or
The unnecessary portion 41 may be cut off with the intermediate molded product 40 covering the intermediate molded product 40.

(3) In the above embodiment, the second ring part 13 was blow molded together with the abdomen 11, but this second ring part 13 was
Similarly to the ring portion 12, the core mold 30 and the blow mold 24.
25 may be compression molded.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent the formation of a lump in the first ring portion, and the height of the first link portion is equal to the distance between the arm and the flange of the retainer. This provides an excellent effect in that the dust cover can be molded to be almost the same.

[Brief explanation of the drawing]

1 to 6 show an embodiment embodying the present invention.
The figure is a cross-sectional view showing the state where the dust cover is attached to the ball joint, Figure 2 is a partial cross-sectional view when the blow mold is opened and a parison is supplied, and Figure 3 is a partial cross-sectional view when the blow mold is closed and the parison is supplied.
Figure 4 is a partial cross-sectional view of the state in which the ring part is shaped.
An enlarged view of part B in the figure, Figure 5 shows the blow mold, die,
FIG. 6 is a partial cross-sectional view of the core and core mold in an open state, and FIG. 6 is a cross-sectional view of the intermediate molded product with unnecessary parts removed. Figures 7 to IO show the prior art, Figure 7 is a sectional view showing the state in which the dust cover is attached to the hole joint, and Figure 8
The figure is a partial cross-sectional view of the state in which the blow mold is opened and the parison is supplied, FIG. 9 is a partial cross-sectional view of the state in which the blow mold is closed and the first link is formed, and FIG. FIG. 1...knuckle arm, 4...hole stud, 5
...Shaft part, 10...Dust cover, 11...Abdomen, 12...First link part, 13...Second ring part, 16...Retainer, 18...Flange , 24.
25... Blow mold, 27... Core, 30... Core type, 33... Parison, 34... Annular protrusion as a droop prevention protrusion. Patent applicant: Toyoda Gosei Co., Ltd. Agent Patent attorney: Hironobu Onda (and one other person) Figure 2 Medium core type

Claims (1)

[Claims] 1. A ball stud (4) comprising a hollow abdomen (11) and first and second ring parts (12, 13) formed at both ends of the abdomen (11). is fixed on the arm (1
) and a flange (18) of a retainer (16) fixed to the shaft (5) of the ball stud (4), in which the first ring part (12) is interposed.
), the method includes: supplying a parison (33) between a pair of opened blow molds (24, 25), the blow molds (24, 25) and a core (27); A part of the parison (33) is compressed by clamping a core mold (30) having a protrusion for preventing drooping (34);
forming the parison (33) into the first ring part (12) with the protrusion (34) preventing the bottom of the first ring part (12) from sagging; 33) By supplying air inside, the parison (33) is expanded to form a blow mold (24, 2).
5) A method for manufacturing a dust cover, comprising the steps of: pressing and shaping into the abdomen (11); and cooling and solidifying the shaped parison (33).