JP2006015731A - Joint boots manufacturing method and heater used therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint boots manufacturing method capable of uniformly molding the wall thickness of a bellows part, and a heater used therein. <P>SOLUTION: In the joint boots manufacturing method, a cylindrical parison 15 is molded using a molding material and only the third parison part 14 among the first parison part 12 corresponding to a large diameter side attaching part, the second parison part 13 corresponding to a small diameter attaching part and the third parison part 14 corresponding to the bellows part is heated to a set temperature by the heater B. Thereafter, the third parison part 14 is covered with an outer mold and gas is ejected to the inner peripheral surface of the third parison part 14 while the third parison part 14 is pressed to the outer mold to mold a bellows part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention connects a cylindrical large-diameter side mounting portion that is mounted by fitting a plurality of convex portions projecting on the inner peripheral portion to the concave portion of the outer case, and a small-diameter side mounting portion that is attached to a shaft, The present invention relates to a joint boot manufacturing method for manufacturing a joint boot including a bellows portion and a heating device used in the method.

  One of the constant velocity joints provided on a drive shaft of an automobile is a tripod type constant velocity joint that can change its position in the axial direction and transmit rotational force. As shown in FIG. 11 and FIG. 12, this constant velocity joint has three trunnions 31 with rollers protruding from the shaft 3 on the input side (or output side) in the direction perpendicular to the axis, and the output side (or input side). The outer case 1 is provided at the end of the shaft 40, and three grooves 34 on which the roller 32 rolls are distributed in the circumferential direction on the inner peripheral portion of the outer case 1. 33 is a triport.

  The joint boot described at the beginning is provided with respect to such a constant velocity joint, prevents dust and foreign matter from entering the constant velocity joint, and holds grease around the constant velocity joint. The outer case 1 is provided with a plurality of concave portions 8 that are recessed radially inward in the circumferential direction to reduce the weight of the case. Correspondingly, a plurality of convex portions 7 projecting radially inward are provided on the inner peripheral portion of the large-diameter side attachment portion 2 of the joint boot in a circumferential direction.

  Conventionally, as a manufacturing method of the above joint boot, a cylindrical parison is injection-molded with a molding material made of resin or the like, and then the first parison portion corresponding to the large diameter side mounting portion and the small diameter side mounting portion are used. Of the corresponding second parison portion and the third parison portion corresponding to the bellows portion, the third parison portion is covered with an outer mold, gas is injected onto the inner peripheral surface of the third parison portion, There was an injection blow molding method in which the bellows part was molded by pressing 3 parison parts.

  According to this molding method, since only the third parison portion is blow-molded, there is an advantage that the large-diameter side mounting portion and the small-diameter side mounting portion can be molded even if they have different diameters.

  However, according to the above-described conventional manufacturing method, the temperature distribution of the parison varies when the cylindrical parison is molded in the parison molding process, and the temperature is high when the third parison portion corresponding to the bellows portion is blow molded. The part swells well and the part having a low temperature hardly swells, making it difficult to uniformly form the thickness of the bellows part.

  An object of the present invention is to provide a method for manufacturing a joint boot capable of uniformly forming the thickness of the bellows portion and a heating device used in this method.

The invention according to claim 1 is characterized in that a plurality of convex portions projecting on the inner peripheral portion are fitted to and attached to the concave portion of the outer case, and a cylindrical large-diameter side attaching portion and a small-diameter side attaching attached to the shaft A joint boot comprising a portion and a bellows portion connecting them,
Molding a cylindrical parison with molding material,
Of the first parison portion corresponding to the large diameter side attachment portion, the second parison portion corresponding to the small diameter side attachment portion, and the third parison portion corresponding to the bellows portion, only the third parison portion is included. Heat to the set temperature with a heating device,
Thereafter, the third parison part is covered with an outer mold, gas is injected onto the inner peripheral surface of the third parison part, and the third parison part is pressed against the outer mold to form the bellows part. .

  According to this means, only the third parison portion corresponding to the bellows portion is heated to the set temperature by the heating device, and then the third parison portion is blow-molded, so that the third parison portion in the state before the blow molding is performed. Variations in temperature distribution can be made difficult to occur. As a result, when the third parison portion is blow-molded, the third parison portion can be uniformly expanded, and the thickness of the bellows portion can be uniformly formed.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the first parison portion is fitted concentrically to the lower fitting portion of the support, and the second parison portion is the support. The parison is externally fitted to the upper fitting portion, and the parison is supported by the support so that the third parison portion surrounds the upper and lower intermediate portions of the support in a concentric manner. The third parison portion is heated from the radially outer side while rotating the support around the axis of the support.

  According to this means, since the third parison portion is heated from the radially outer side while rotating the support around the axis of the support, the third parison portion can be heated uniformly. In addition, since the third parison portion surrounds the upper and lower intermediate portions of the support in a concentric manner with an interval, the inner periphery of the third parison portion is not cooled by the support, and the third parison portion A problem that a temperature difference occurs between the inner peripheral surface side and the outer peripheral surface side can be prevented. Therefore, variations in the temperature distribution of the third parison portion can be made more difficult to occur.

  The invention of claim 3 is characterized in that, in the invention of claim 2, the first parison portion is covered with the lower cover member, and the first fitting hole provided in the lower cover member is provided in the first parison portion. And the second cover portion is covered with the upper cover member, and a second fitting hole provided in the upper cover member is provided in the second fitted portion of the second parison portion. It is in the point to be fitted.

  According to this means, the first parison portion and the second parison portion are hardly heated by the heating device, and deformation of the large-diameter side attachment portion and the small-diameter side attachment portion due to the heating of both parison portions is suppressed. be able to. In addition, the first fitting hole provided in the lower cover member is externally fitted to the first fitted portion of the first parison portion, and the second fitting hole provided in the upper cover member is set to the second of the second parison portion. The parison can be reliably fixed to the support by being externally fitted to the fitted portion.

  According to a fourth aspect of the present invention, in the invention of the third aspect, after the heating of the third parison portion is completed, the parison is covered with the outer mold while being supported by the support, and the support is supported. It is in the point which injects the said gas from the injection port provided in.

  According to this means, since the gas is injected from the injection port provided in the support body, after the heating of the third parison portion is completed, the parison is newly supported by a member dedicated to blow molding provided with the injection port. Therefore, it is possible to reduce the labor required for blow molding.

A feature of the invention described in claim 5 is a heating device used in the method for manufacturing a joint boot according to claim 3 or 4,
A plurality of the support bodies are arranged on the lower conveyor at intervals in the transport direction, and a rotation drive mechanism is provided between each support body and the lower conveyor for rotating the support bodies around the axis. The lower cover member divided into a plurality of portions is provided on the radially outer side of the lower end of the support so as to be freely expandable and contractible.
A plurality of the upper cover members that are suspended and supported on the upper conveyor facing the lower conveyor at intervals in the conveying direction, and that the upper cover member is moved up and down between each upper cover member and the upper conveyor. A mechanism is provided, wherein the upper cover member is divided into a plurality of parts so that the upper cover member can be expanded and contracted, and a rotation driven mechanism is provided that allows rotation of the upper cover member around a longitudinal axis with respect to the upper conveyor. The heater is arranged on both lateral sides between the conveyor.

  According to this configuration, the following effects can be achieved.

  The lower cover member of the support provided on the lower conveyor is in an expanded state, the first parison part is fitted concentrically to the lower fitting part of the support, and the second parison part is the support. The parison is externally fitted to the upper fitting portion of the first and second parisons, and the parison is supported by the support so that the third parison portion surrounds the upper and lower intermediate portions of the support in a concentric manner. Then, the diameter of the lower cover member is reduced to cover the first parison portion with the lower cover member, and the first fitting hole provided in the lower cover member is externally fitted to the first fitted portion of the first parison portion. To do. Next, the diameter of the upper cover member suspended from and supported by the upper conveyor is increased, and the lifting mechanism is driven to lower the upper cover member. Then, the upper cover member is reduced in diameter so as to cover the second parison portion with the upper cover member, and the second fitting hole provided in the upper cover member is externally fitted to the second fitted portion of the second parison portion.

  The upper and lower conveyors are transported and driven, and the third parison portion is heated by the heaters on both lateral sides between the lower conveyor and the upper conveyor while rotating the support around the axis of the support. . In this case, the upper cover member is driven and rotated integrally with the support body while covering the second parison portion by the action of the rotation driven mechanism.

  In this way, the plurality of parisons are sequentially supported by the plurality of supports, and the third parison portion of each parison is heated. Thereby, the 3rd parison part of a some parison can be heated continuously, and the efficiency of a heating operation | work can be raised.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the joint boot which can shape | mold the thickness of a bellows part uniformly, and the heating apparatus used for this method were able to be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIGS. 11 and 12 show a triport type constant velocity joint of an automobile, and FIGS. 4 and 5 show a joint boot made of thermoplastic elastomer resin for the constant velocity joint.

  In the constant velocity joint, three trunnions 31 with rollers protrude from the shaft 3 on the input side in the direction perpendicular to the axis, and the outer case 1 is provided at the end of the shaft 40 on the output side. Three grooves 34 on which the roller 32 rolls are distributed and arranged in the circumferential direction. 33 is a triport.

  The joint boot includes a cylindrical large-diameter side attachment portion 2 that is externally fitted to the outer case 1, a cylindrical small-diameter side attachment portion 4 that is attached to the shaft 3, and a bellows portion 5 that connects them. The outer peripheral surface 2A of the large-diameter side mounting portion 2 is formed in a circular cross section, and the three convex portions 7 projecting radially inward are provided on the inner peripheral portion 55 of the large-diameter side mounting portion 2. In the circumferential direction, the holes are uniformly dispersed every 120 degrees, the hollow holes 56 are formed in the convex portion 7, and the three concave portions 8 are formed in the three concave portions 8 formed in the outer peripheral portion of the outer case 1. It is configured to be separately fitted. This joint boot is formed through the following parison molding process, heating process and blow molding process.

[Parison molding process]
As shown in FIG. 1, the molding material is discharged from the nozzle 11 of the parison molding apparatus A, and the first parison portion 12 corresponding to the large diameter side mounting portion 2 and the second parison portion 13 corresponding to the small diameter side mounting portion 4. And a cylindrical parison 15 composed of the third parison portion 14 corresponding to the bellows portion 5.

[Heating process]
As shown in FIG. 2, only the third parison portion 14 out of the first parison portion 12, the second parison portion 13, and the third parison portion 14 is heated to a set temperature (for example, 160 ° C. to 200 ° C.) by the heating device B. To do. The heating device B is configured as follows so that a plurality of parisons 15 can be continuously heated.

  As shown in FIGS. 6 to 10, a plurality of stepped cylindrical supports 16 for the parison 15 are arranged on the lower conveyor 17 in a vertical posture with a certain interval in the transport direction. Between the lower conveyor 17 and the lower conveyor 17 is provided with a rotation drive mechanism M for rotating the support 16 around the axis O of the support 16, and 2 in the radial direction on the radially outer side of the lower end of the support 16. A divided cylindrical lower cover member 18 is provided so as to be able to be expanded and contracted.

  The support 16 is spaced from the support base 19 on the lower end side, the lower fitting portion 20 having a smaller diameter than that of the first parison portion 12 so that the first parison portion 12 is fitted concentrically, and the third parison portion 14. It consists of an upper and lower intermediate part 21 surrounded and an upper fitting part 22 for fitting the second parison part 13 concentrically.

  Then, a plurality of cylindrical upper cover members 24 are suspended and supported on the upper conveyor 23 facing the lower conveyor 17 at regular intervals in the conveying direction, and between each upper cover member 24 and the upper conveyor 23. A cylinder 25 (equivalent to an elevating mechanism) for raising and lowering the upper cover member 24 is provided, and the upper cover member 24 is divided into two in the radial direction so that it can be expanded and contracted (expanded / reduced diameter). A bearing 26 (corresponding to a rotation driven mechanism) that allows rotation around the vertical axis P is provided, and a pair of long far-infrared heaters 53 are provided on both lateral outer sides between the lower conveyor 17 and the upper conveyor 23. They are arranged separately.

With the above structure,
(1) The lower cover member 18 of the support 16 provided on the lower conveyor 17 is in a diameter-enlarged state, and the first parison portion 12 is fitted concentrically to the lower fitting portion 20 of the support 16. The second parison portion 13 is externally fitted concentrically to the upper fitting portion 22 of the support 16, and the third parison portion 14 surrounds the upper and lower intermediate portions 21 of the support 16 in a concentric manner with a space therebetween. The parison 15 is supported on the support 16 so as to be in the state of the dead (see FIG. 6).

  (2) The diameter of the lower cover member 18 is reduced to cover the first parison portion 12 with the lower cover member 18, and the first fitting hole 27 (see FIG. 6) provided in the lower cover member 18 is the first. It is fitted on the first fitted portion 28 of the parison portion 12 (see FIG. 7).

  (3) The upper cover member 24 suspended from and supported by the upper conveyor 23 is in an expanded state (see FIG. 7), and the cylinder 25 is driven to extend to lower the upper cover member 24. Then, the upper cover member 24 is reduced in diameter to cover the second parison portion 13 with the upper cover member 24, and the second fitting hole 29 (see FIG. 7) provided in the upper cover member 24 is provided in the second parison portion 13. It fits to the fitted part 50 (refer FIG. 8).

  (4) As shown in FIGS. 8, 9, and 10, the upper conveyor 23 and the lower conveyor in a state where the longitudinal axis P of the upper cover member 24 is positioned on the extension line of the axis O of the support 16. The third parison portion 14 is heated by the heaters 53 on both lateral sides between the lower conveyor 17 and the upper conveyor 23 while the support 17 is driven and rotated around the axis O. In this case, the upper cover member 24 is driven and rotated integrally with the support body 16 while covering the second parison portion 13 by the action of the bearing 26.

  In this way, the plurality of parisons 15 are sequentially supported by the plurality of supports 16, and the third parison portion 14 of each parison 15 is heated. Thereby, the 3rd parison part 14 of the some parison 15 is heated continuously.

[Blow molding process]
After the heating of the third parison portion 14 is completed, as shown in FIG. 3, the mold surface is covered with the bellows-shaped outer mold 51 while the parison 15 is supported on the support body 16, and the upper and lower portions provided on the outer mold 51 are provided. A pair of fitting holes 52 are externally fitted to the upper cover member 24 and the lower cover member 18, respectively, and gas is emitted from an injection port (not shown) provided in the support 16 to the inner peripheral surface of the third parison portion 14. And the third parison portion 14 is pressed against the outer mold 51 to form the bellows portion 5.

Diagram showing the parison molding process Diagram showing the heating process Diagram showing blow molding process Partial cutaway view showing joint boots Figure showing the joint diameter mounting part of the joint boot The figure which shows a heating device and a heating process The figure which shows a heating device and a heating process The figure which shows a heating device and a heating process Top view showing the lower conveyor, etc. with the parison attached Side view of heating device during heating Vertical section showing constant velocity joint and joint boot Diagram showing constant velocity joint

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer case, 2 ... Large diameter side attaching part, 3 ... Shaft, 4 ... Small diameter side attaching part, 5 ... Bellows part, 7 ... Convex part, 8 ... Concave part, 12 ... 1st Parison portion, 13 ... 2nd parison portion, 14 ... 3rd parison portion, 15 ... Parison, 16 ... support, 17 ... lower conveyor, 18 ... lower cover member, 20 ... lower side Fitting part, 21 ... upper and lower intermediate part, 22 ... upper fitting part, 23 ... upper conveyor, 24 ... upper cover member, 25 ... elevating mechanism, 26 ... rotation driven mechanism, 27 ... first Fitting hole 28... First fitting portion 29... Second fitting hole 50... Second fitting portion 51. Outer mold 52. Fitting hole 53. , 55... Inner circumference, B... Heating device, O... Axis of support, P.

Claims (5)

A cylindrical large-diameter side mounting portion that is attached by fitting a plurality of convex portions projecting on the inner peripheral portion to the concave portion of the outer case, a small-diameter side mounting portion that is attached to the shaft, and a bellows portion that connects these A method of manufacturing a joint boot comprising:
Molding a cylindrical parison with molding material,
Of the first parison portion corresponding to the large diameter side attachment portion, the second parison portion corresponding to the small diameter side attachment portion, and the third parison portion corresponding to the bellows portion, only the third parison portion is included. Heat to the set temperature with a heating device,
Thereafter, the third parison part is covered with an outer mold, gas is injected onto the inner peripheral surface of the third parison part, and the third parison part is pressed against the outer mold to form the bellows part. Production method.   The first parison portion is fitted concentrically to the lower fitting portion of the support, the second parison portion is fitted concentrically to the upper fitting portion of the support, and the third parison portion The parison is supported by the support so that the upper and lower intermediate portions of the support are concentrically surrounded at intervals, and the support is rotated around the axis of the support while the support is rotated. The manufacturing method of the joint boot of Claim 1 which heats a 3rd parison part from a radial direction outer side.   The lower cover member covers the first parison portion, and a first fitting hole provided in the lower cover member is externally fitted to a first fitted portion of the first parison portion, and the upper cover member The method for manufacturing a joint boot according to claim 2, wherein the second parison part is covered and a second fitting hole provided in the upper cover member is externally fitted to a second fitted part of the second parison part.   The joint boot according to claim 3, wherein after the heating of the third parison portion is completed, the parison is covered with the outer mold while being supported by the support, and the gas is injected from an injection port provided in the support. Manufacturing method. A heating device used in the method for manufacturing a joint boot according to claim 3 or 4,
A plurality of the support bodies are arranged on the lower conveyor at intervals in the transport direction, and a rotation drive mechanism is provided between each support body and the lower conveyor for rotating the support bodies around the axis. The lower cover member divided into a plurality of portions is provided on the radially outer side of the lower end of the support so as to be freely expandable and contractible.
A plurality of the upper cover members that are suspended and supported on the upper conveyor facing the lower conveyor at intervals in the conveying direction, and that the upper cover member is moved up and down between each upper cover member and the upper conveyor. A mechanism is provided, wherein the upper cover member is divided into a plurality of parts so that the upper cover member can be expanded and contracted, and a rotation driven mechanism is provided that allows rotation of the upper cover member around a longitudinal axis with respect to the upper conveyor. The heating apparatus which has arrange | positioned the heater on the both sides outer side between conveyors.

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