JPH03129172A - Bellows shape part and its manufacture - Google Patents

Abstract

PURPOSE:To comparatively simply mould the part in the title in one body by releasing a central mould after molding the part with the central mould to mould the inside surface of central both sides in the lengthy direction and a pair of edge part moulds to mould the inside surface of both edges in the lengthy direction and thereafter, respectively releasing the pair of edge part moulds. CONSTITUTION:A bellows shape part and a product cavity of the same shape are moulded among main moulds 54, 56, a central mould 58 and edge part moulds 60, 62 and a melting material of soft vinyl chloride is injected into the cavity so that the bellows shape part (cover) is moulded in one body. After the cover is moulded and hardened, initially the moulds 54, 56 are relatively separated and the mould 58 is pulled out to the right below. Secondly, the mould 60 is slid to the central part in the lengthy direction of a sectional surface shape almost in parallel with a slit 52 along a guide surface 68 and then pulled out to the right below. Also, when the mould 62 is released, at first a setting part and a bellows part 48 are moved in the left direction, and thereafter, the cover is relatively pulled out against the mould 62 in the left above direction.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is provided with a bellows portion that is expandable and contractible by a plurality of pleats and that has a hollow longitudinal cross section substantially perpendicular to the direction of expansion and contraction. Regarding bellows-shaped parts, especially,
The present invention relates to a bellows-shaped component that is easily manufactured using a core that is divided into a plurality of parts, and a method for manufacturing the same.

BACKGROUND ART A bellows-shaped part having a hollow bellows part that can be expanded and contracted by a plurality of folds is used as a cover for covering the base end of a shift lever of an automobile, for example. It has been considered to cover the base end of the parking brake lever using a similar bellows-shaped component. However, since the cross-sectional shape of the base end of the parking brake lever is elongated in the direction of rotation of the parking brake lever, even in the bellows-shaped part, the cross-sectional shape is approximately perpendicular to the direction of expansion and contraction. It has a hollow, elongated shape, and it is difficult to mold it in one piece. In other words, when integrally molding such a bellows-shaped part,
Since the folds of the bellows part become undercuts, the core is extracted by pushing outward while elastically deforming the folds. However, when the cross section becomes a longitudinal shape as shown above, the longitudinal direction The elastic deformability of the end portion decreases, resulting in damage when the core is pulled out.

In particular, when molding a bellows-shaped part that has a grip part etc. integrally continuous with the bellows part, it is necessary to use a soft synthetic resin material with relatively high hardness as the molding material. This makes extraction even more difficult.

On the other hand, even with such bellows-shaped parts, by dividing the core into multiple parts, it is possible to release the core without damaging the folds, but simply dividing the core is not enough. The number of divisions increases, the molding equipment becomes complicated, and there are problems such as insufficient productivity.

The present invention has been made against the background of the above-mentioned circumstances, and its purpose is to enable comparatively simple integral molding of a bellows-shaped part having a bellows portion having a hollow longitudinal shape in cross section. There is a particular thing.

Means for Solving the Problems In order to achieve the above object, the present invention provides a bellows section which is expandable and contractible by a plurality of pleats and has a hollow longitudinal cross section substantially perpendicular to the direction of expansion and contraction. and a posture in which the longitudinal direction of the elongated shape is the rotating direction of the rotating member such that the base end of the rotating member that is rotated in a predetermined angular range around one axis is covered by the bellows part. It is a bellows-shaped part made of an elastic material that is attached to the body and is integrally molded using a core that is divided into multiple parts.
a) Determine the depth of the folds on both sides of the center in the longitudinal direction of the longitudinal shape in the cross section of the bellows portion, in which expansion and contraction during rotation of the rotation member is relatively small in relation to the uniaxial axis, when the rotation member is rotated. (c) The width dimension in the direction perpendicular to the longitudinal direction of the cross section is made smaller from the longitudinal center portion toward the both ends. It is characterized in that the core is gradually made smaller and the core divided into a plurality of parts is extracted at the central portion in the longitudinal direction.

Further, the manufacturing method of the present invention, which can suitably manufacture such a bellows-shaped component by integral molding, includes: (C) a central mold for molding the inner surfaces of both sides of the center in the longitudinal direction as the core divided into a plurality of parts; After the bellows-shaped part is integrally molded using an elastic material by using a pair of end molds that mold the inner surfaces of both ends in the longitudinal direction, (d) the folds on both sides of the center in the longitudinal direction are elastically deformed. (e) Then, each of the pair of end molds is relatively moved toward the central portion in the longitudinal direction and released.

Here, such a bellows-shaped component is suitably used, for example, as a cover that covers the base end of a parking brake lever, but it may also be attached to other rotating members.

The above-mentioned bellows-shaped part may be composed only of the bellows part, but when used as a cover for a parking brake lever, it is possible to use a part other than the bellows part, such as by providing a relatively thick grip part continuously and integrally with the bellows part. It may also include component parts. When the above-mentioned grip part is provided, it is desirable that the core disposed inside the grip part during integral molding be integrally provided in either one of the pair of end molds. It may be provided separately from the core of the bellows part.

Furthermore, it is not necessarily necessary to make the depth of the folds at both sides of the center in the longitudinal direction smaller than the depth of the folds at both longitudinal ends. If the undercoat 14 becomes smaller as it goes, the depth of the folds is changed in the circumferential direction only in the part on the proximal end side in the direction of expansion and contraction, and the depth of the pleats is uniform in the part on the distal side in the direction of expansion and contraction. There is no problem even if it is provided.

Further, as the elastic material, a soft synthetic resin material such as soft vinyl chloride is preferably used, but other elastic materials can also be used.

In addition, injection molding can be suitably used as a molding means for integrally molding, but other molding methods can also be employed.

Actions and Effects of the Invention In other words, the amount of expansion and contraction of the bellows portion due to the rotation of the rotation member differs in each part of the cross section substantially perpendicular to the direction of expansion and contraction, and the position with respect to the uniaxial axis that is the center of rotation of the rotation member. Therefore, in the present invention, by appropriately determining the positional relationship between the one axis and the bellows portion, the amount of expansion and contraction at the center portion in the longitudinal direction of the longitudinal shape in the cross section of the bellows portion is equal to the amount of expansion and contraction at both ends in the longitudinal direction. In addition, the depth of the folds in the central part in the longitudinal direction where the amount of expansion and contraction is smaller is made smaller than in other parts, and the width dimension in the direction perpendicular to the longitudinal direction in the cross section is made smaller than the central part in the longitudinal direction. The size gradually decreases toward both ends.

In this way, for example, as in the method of the present invention, as a core for molding the bellows part, a central mold for molding both sides of the center in the longitudinal direction and a pair of end molding molds for molding both ends in the longitudinal direction are used. Using a mold, a bellows-shaped part is integrally molded by injection molding or the like, and after the molding, the central mold is extracted and released, and then the pair of end molds are moved relative to each other in the longitudinal direction toward the central portion. such as pulling it out
- The number of core divisions during body molding can be reduced to at least three, and bellows-shaped parts with a longitudinal cross section can be manufactured relatively easily.

Here, when the above-mentioned mold is released, the folds of the bellows part become undercuts, but the depth of the folds on both sides of the longitudinal center formed by the central mold is relatively small, and the amount of undercut is is small, and the forming area is relatively flat in the longitudinal center of the cross-sectional shape, so the elastic deformability of the formed pleats is relatively high, and the central forming mold can be removed without damaging the folds. It is possible. In addition, regarding the pair of end molds,
First, the relative movement is made toward the central portion in the longitudinal direction, but the width dimension in the cross section gradually decreases from the central portion in the longitudinal direction toward both ends.
This creates a draft angle that can be easily moved relative to the mold, which allows the mold to be released from the longitudinal end with the large pleats, and then proceed as in the case of the central mold above. It is pulled out while elastically deforming the folds on both sides of the center. At this time, there is no problem even if the end mold and the folds at the longitudinal ends of the bellows portion partially interfere with each other.

As described above, the bellows-shaped part of the present invention can be easily integrally molded using a core divided into at least three parts, and the molding apparatus can be configured simply and inexpensively, and the number of molding steps is small. This makes it possible to obtain productivity that is practically satisfactory. In particular, when producing a bellows-shaped part by the method of the present invention, the core for molding the inner surface of the bellows part is composed of a total of three molds: a central mold and a pair of end molds. Therefore, the above effect becomes even more remarkable.

Note that the method of the present invention is merely an example of a manufacturing method that can suitably manufacture bellows-shaped parts, and when manufacturing the bellows-shaped parts of the present invention, for example, the central mold may be further
By dividing the bellows into three parts, or by making the number of longitudinal divisions in the cross-sectional shape of the bellows part four or more, the core can be extracted at least in the central part in the longitudinal direction where the pleats are relatively small in depth. For example, the number of divisions and the division form of the core can be adjusted as appropriate.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, 10 is a sector fixedly arranged on the body of an automobile (not shown), and the sector 10 includes:
A parking brake lever (hereinafter simply referred to as lever) 14 is attached so as to be rotatable about a pin 12 serving as a single axis, and a ratchet 16 is formed along an arc shape centered on the pin 12. Lever 14
The proximal end 18 is bent to have a U-shaped cross section and is arranged to straddle the sector 10, and the distal end 20
is curved into a cylindrical shape. This lever 14 corresponds to a rotating member.

A brake cable 22 connected to a parking brake (not shown) is locked to the base end 18 of the lever 14, and a ball 26 is attached so as to be rotatable around a pin 24 parallel to the pin 12. The ball 26 is adapted to mesh with the ratchet 16. One end of a release rod 28 is connected to the ball 26 so as to be rotatable about an axis parallel to the pin 24.
A knob 30 fitted to the tip end 20 of the lever 14 is screwed to the other end of the release rod 28 . knob 3
0 is biased by a spring 32 disposed inside the tip portion 20 so as to protrude from the tip portion 20, and thereby the ball 26 is urged in the direction of meshing with the ratchet 16. Further, a pin 3 inserted into the opening 34 formed in the sector 10 is provided at the base end 18.
6 is attached and its pin 36 is brought into contact with the end of the opening 34, thereby defining the original position of the lever 14.

When the lever 14 is rotated clockwise from the original position shown in the figure, the brake cable 22 is tightened and the parking brake is activated, and in this state the ball 26 is moved by the biasing force of the spring 32. When the lever 14 is engaged with the ratchet 16, the counterclockwise rotation of the lever 14 is prevented and the operating state of the parking brake is maintained. The dashed line in FIG. 1 shows the state in which the lever 14 is rotated in this manner. In addition, when the parking brake is in operation, the knob 30
When the lever 14 is pushed in, the engagement between the ball 26 and the ratchet 16 is released and the lever 14 is allowed to rotate counterclockwise.In this state, the lever 14 is rotated to its original position to park. Brake operation is released.

On the other hand, a cover 40 integrally molded from soft vinyl chloride is attached to the lever 14. This cover 40 corresponds to a bellows-shaped component that is an embodiment of the present invention, and covers the mounting portion 46 fixed to the bracket 42, 44 provided in the sector 10 and the base end portion 18 of the lever 14. It integrally includes a bellows portion 48 and a grip portion 50 that is fitted and fixed to the tip portion 20 of the lever 14. The mounting part 46 covers the lower part of the sector
In the figure, it has a hollow cylindrical shape that is long in the left and right direction, and is fixed to the brackets 42 and 44 at both ends in the longitudinal direction. Furthermore, the grip portion 50 is attached to the mounting portion 46. It has a substantially cylindrical shape with a thickness smaller than that of the bellows part 48, and although not shown, the inner surface thereof has many fine annular irregularities in the axial direction. It is press-fitted and fixed so that it cannot move relatively.

The bellows portion 48 can be expanded and contracted by a large number of folds 52, and when the lever 14 is rotated counterclockwise around the pin 12, the lower portion in the figure is shortened and the upper portion is expanded. On the other hand, when the lever 14 is rotated clockwise around the pin 12, the upper portion in the figure is shortened and the lower portion is extended, allowing such rotational operation. In addition, the cross section substantially perpendicular to the direction of expansion and contraction has a hollow longitudinal shape that is long in the direction of rotation of the lever 14, taking into consideration the shape and movement of the base end 18 of the lever 14. The longitudinal dimension of the elongated shape is the base end of the bellows portion 48, that is, the attachment portion 46.
It is long at the boundary with the grip part 50, corresponding to the attachment part 46, and gradually becomes shorter toward the tip in the expansion/contraction direction, that is, toward the boundary with the grip part 50. Note that the width dimension perpendicular to the longitudinal direction is also slightly smaller toward the distal end in the expansion/contraction direction, but this change is not as large as the longitudinal dimension.

FIG. 2 shows the bellows portion 48 in the rV-IV cross section of FIG. 3.
1, the right side of the figure corresponds to the upper side of FIG. 1, and the left side corresponds to the lower side.

Also, folds 52 at various parts in the cross section of the bellows portion 48
The depth dl of the folds 52 on both sides 48a and 48b of the center in the longitudinal direction of the longitudinal shape in the cross section is as follows: Both ends 48c, 48 in the longitudinal direction of the elongated shape
The depth dz of the pleats 52 at d is smaller than d3.

That is, the amount of expansion and contraction of each part of the cross section differs depending on the positional relationship with the bin 12, which is the center of rotation of the lever 14, but in this embodiment, the amount of expansion and contraction at both central sides 48a and 48b is the same as that at both ends 48c.

Bin 1 so that it is smaller than the amount of expansion and contraction at 48d.
The positional relationship between 2 and the bellows part 4 is determined, and the depth d at both central sides 48a and 48b is determined by the amount of expansion and contraction.
It is believed that it is possible to reduce .

FIG. 6 is a diagram illustrating the amount of expansion and contraction of each part of the bellows portion 48 in this embodiment. , the amount of expansion and contraction t1 during rotation between the intermediate position shown by the solid line and the original position shown by the dashed-dotted line, and the amount of expansion and contraction during rotation between the intermediate position and the operating position shown by the dashed-dotted line. This is (t1+t2), which is the sum of the amount of expansion and contraction L2 during rotation.

Further, the amount of expansion and contraction of the upper end 48c that is rotated around point 02 is similarly expressed as O (tz+t, a), and the amount of expansion and contraction of the upper end 48c that is rotated around point 03 is expressed as (tz+t, a).
The amount of expansion and contraction of 8d is expressed as (L, +L6). Then, the expansion/contraction ffi (tl + t, 2) is the expansion/contraction amount (tz+
The positional relationship between the bin 12 and points 01, 02, and 03 is determined so that it is smaller than t4) and (ts+t6). In this case, in this embodiment, (t, +t2
)<(t3+t4)<(t,+t6), and the depth of each part of the pleats 52 also corresponds to d+<dz<
d3, and the pleats 52 are smoothly connected through a gradual change portion where the depth changes gradually. Note that this depth dd2
．． di gradually decreases from the mounting portion 46 side toward the grip portion 50 side while maintaining the relationship dl<dz<dz.

Further, the width dimension of the longitudinal shape in the above-mentioned cross section, that is, the dimension in the direction perpendicular to the longitudinal direction, is largest at the central portion in the longitudinal direction and at both ends 48c.

It is determined that it becomes gradually narrower toward 48d.

The cover 40 with the shapes of each part determined as described above,
As shown in FIG. 3 and FIG. 4 showing the IV-IV cross section thereof, a pair of main molds 54 and 56 each having a molding surface corresponding to the outer circumferential shape of the cover 40, and a core. a central mold 58 and a pair of end molds 60,62.
By using these, it is possible to easily integrally mold the material by injection molding. In this case, the cover 40 needs to be molded in such a way that the folds 52 of the bellows part 48 are parallel to each other, and the lever 14 is within its rotational operation range, as shown by the solid line in FIG. The molding surfaces of each of the molds 54, 56, 58, and 60° 62 are formed to match the shape of the cover 40 held in the intermediate position.

The main molds 54 and 56 are configured with the parting line of the plane of FIG. 3, which is symmetrical to the cover 40, and have identical molding surfaces.

In addition, on the 5th day of the central mold, the central both sides 48 of the bellows portion 48
It is for molding the portions near the mounting portions 48a and 48b and the portions of the mounting portion 46 that are continuous with the central side portions 48a and 48b, and is provided with molding surfaces corresponding to the inner shapes thereof. The end mold 6o is disposed in close contact with the central mold 58, and is located near the end 48c and the mounting portion 46.
It is for molding a portion continuous to the end portion 48c, and is provided with a molding portion corresponding to the inner shape of the portion.

The end mold 62 is disposed in close contact with the central mold 58, and is used to mold a portion near the end 48d, a portion of the attachment portion 46 that is continuous with the end 48d, and the grip portion 50. It is equipped with a molded part that corresponds to the shape of the inner surface.

Here, the contact surfaces 64 and 66 of the central mold 58 that are brought into close contact with the end molds 60 and 62 are provided with the central mold 58.
A draft angle is provided for extracting the material toward the lower right in FIG. 3. Further, at the boundary between the bellows part 48 of the end mold 62 and the grip part 50, a guide surface 68 that guides the end mold 60 toward the central part in the longitudinal direction is provided with the pleats 52.
It is formed almost parallel to.

Then, by assembling the respective molds 54, 56, 58, 60° 62, the main mold 54° 56 and the central mold 58. A product cavity having the same shape as the cover 40 is formed between the end molds 60 and 62, and the cover 40 is integrally molded by injecting a molten material of soft vinyl chloride into the cavity.

After that, when the cover 40 is molded and hardened, first, the main molds 54 and 56 are relatively separated and released from the cover 40, and then the central mold 58 is pulled out toward the lower right in FIG. .

At this time, the folds 52 of the bellows portion 48 become undercuts, and the depth d of the folds 52 of the central side portions 48a, 48b formed by the central mold 58.

is relatively small and the amount of undercant is small,
Since the molding range is a relatively narrow and flat portion in cross-sectional shape, the elastic deformability of the molded pleats 52 is relatively high, and the mold 58 can be easily moved while elastically deforming the folds outward without damaging them. It can be extracted. Further, since a draft angle is provided on the contact surface 64.66 of the central mold 58 with the end molds 60.62, the central mold 58 interferes with those end molds 60.62. It is taken out without any problem.

After the central mold 58 is extracted, the end mold 60 is then removed as shown by the dashed line in FIG. 3 and in FIG.
is slid along the guide surface 68 substantially parallel to the pleats 52 toward the central portion in the longitudinal direction of the cross-sectional shape. The cross-sectional shape of the bellows portion 48 has the largest width at the center portion in the longitudinal direction, and gradually narrows toward the end portion 48c, so this becomes a draft angle and the mold 60 is easily moved toward the center portion. As a result, the mold 60 is released from the end portion 48C having the folds 52 having a relatively large depth d2. And, like the central mold 58, this mold 60 has central both sides 48a, 48.
While elastically deforming the folds 52, which have a relatively small depth dimension b, they are pulled out toward the lower right in FIG. At this time, the folds 52 of the end portion 48c of the bellows portion 48 partially interfere with the mold 60, but the amount of elastic deformation thereof is small and no damage occurs due to this. Note that when the end molding die 60 is extracted, the molding die 60 is extracted more easily than the central molding die 58 because elastic deformation of the portion other than the portion formed by the end molding die 62 is allowed.

In addition, when releasing the end mold 62, first move the attachment part 46 and the bellows part 48 to the left in FIG.
The mold 62 is relatively released from the mold. Thereafter, the cover 40 may be pulled out toward the upper left in FIG. 3 relative to the mold 62 while elastically deforming the grip portion 50 and the center side portions 48a, 48b of the bellows portion 48. At this time,
Since the bellows portion 48 is allowed to be elastically deformed over its entire circumference, extraction from the bellows portion 48 is easier than in the case of the mold 60.

When attaching the cover 40 manufactured in this manner to the lever 14, first, the tip portion 20 of the lever 14 is inserted into the attachment portion 46 and the bellows portion 48, and the grip portion 50 is attached to the lever 14. Press fit into the tip 20 of the holder and fix. Next, both longitudinal ends of the mounting portion 46 may be fixed to the brackets 42 and 44 using screws or the like.

As described above, in this embodiment, the relatively hard cover 40 including the bellows portion 48 having a longitudinal cross section can be easily manufactured by injection molding. Moreover, the core for molding the inner surface of the cover 40 is the central mold 5.
8 and a pair of end molds 60, 6.2, the molding device is simple and inexpensive, and the number of molding steps is small, resulting in practically satisfactory productivity. is obtained.

Further, since the cover 40 is integrally provided with a relatively thick grip portion 50, a cover that covers only the base end portion I8 of the lever 14 and a grip that is fitted to the tip portion 20 may be provided separately. Compared to the previous version, the manufacturing and installation man-hours are halved, and the design is also superior.

In addition, since soft vinyl chloride is used as the elastic material in this embodiment, the required hardness of the grip part 50 is ensured while allowing the bellows part 48 to expand and contract. The operability when rotating 14 is not impaired.

Furthermore, since the injection molding method is used in this embodiment, the cover 40 including the thick grip portion 50 and the thin attachment portion 46° bellows portion 48 can be efficiently molded in one piece.

It should be noted that the above-mentioned embodiment is merely a specific example of the present invention, and the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a parking brake operating device which is an embodiment of the present invention and is equipped with a bellows-shaped component manufactured according to the method of the present invention. 2 is a cross-sectional view of the bellows-shaped part of FIG. 1; FIG. FIG. 3 is a sectional view showing a main part of a molding apparatus for injection molding the bellows-shaped part shown in FIG. 1. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. Fifth
This figure is a cross-sectional view showing the step of extracting the end mold in the molding apparatus shown in FIG. 3. FIG. 6 is a diagram illustrating the amount of expansion and contraction of each part of the bellows-shaped component as the parking brake lever rotates. 2: Pin (single axis) 4: Parking brake lever (rotating member) 8: Base end O: Cover (bellows-shaped part) 8: Bellows portion 8a, 48b: Longitudinal center side portion 8c, 48d: Longitudinal end Part 2: Folds 58: Center mold 0.62: End mold, d, d, ,: Depth of pleats

Claims (2)

[Claims] (1) It has a bellows part that can be expanded and contracted by multiple pleats and has a hollow longitudinal cross section that is substantially perpendicular to the direction of expansion and contraction, and can be rotated around a single axis within a predetermined angular range. The base end of the rotating member is covered by the bellows portion, and the longitudinal direction of the elongated shape is the rotating direction of the rotating member. A bellows-shaped component made of an elastic material and integrally molded, wherein expansion and contraction during rotation of the rotating member is relatively small in relation to the uniaxial axis, and the longitudinal center of the longitudinal shape in the cross section of the bellows portion. The depth of the folds on both sides is made smaller than the depth of the folds on both longitudinal ends of the longitudinal shape, which undergo relatively large expansion and contraction during the rotation, and the width dimension in the direction perpendicular to the longitudinal direction in the cross section is made smaller. 1. A bellows-shaped component, characterized in that the core is gradually smaller from the central portion in the longitudinal direction toward both ends, and the core divided into a plurality of pieces is extracted at the central portion in the longitudinal direction. (2) A manufacturing method for integrally molding the bellows-shaped component according to claim (1), comprising: as the core divided into a plurality of parts, a central mold for molding inner surfaces of both sides of the center in the longitudinal direction; After the bellows-shaped component is integrally molded using an elastic material by using a pair of end molds that mold the inner surfaces of both ends in the longitudinal direction, the folds on both sides of the center in the longitudinal direction are elastically deformed. A method for manufacturing a bellows-shaped part, comprising: releasing a mold, and then relatively moving each of the pair of end molds toward the central portion in the longitudinal direction to release the mold.