JP3876366B2 - Method for manufacturing joint boot and heating device used in this method - Google Patents

Description

  The present invention connects a cylindrical large-diameter side mounting portion that is attached by fitting a plurality of convex portions protruding from the inner peripheral portion to the concave portion of the outer case, and a small-diameter side mounting portion that is attached to the 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 this 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 FIGS. 10 and 11, 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. On the outer periphery of the outer case 1, a plurality of recesses 8 that are recessed radially inward are provided in the circumferential direction so as 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. On the other hand, the outer peripheral surface of the large-diameter side attachment portion 2 is formed in a circular cross section for tightening by the ring-shaped band 9.

  Conventionally, a joint boot made of resin is generally manufactured by molding a small-diameter side attachment portion by injection molding and then blow-molding other bellows portions and a large-diameter side attachment portion (see, for example, Patent Document 1). ). However, it is necessary to make the large-diameter side mounting portion 2 as described above into an irregular shape having an outer peripheral surface that is a perfect circle and an inner peripheral surface that has convex portions at a plurality of locations in the circumferential direction. In this case, it cannot be produced by such general injection blow molding. This is because, in blow molding, the thickness in the circumferential direction is uniform or substantially uniform, and thus, such a deformed shape cannot be molded by blow molding the large-diameter side attachment portion.

  Therefore, in Patent Document 2, a drawing device having a cavity for forming a small-diameter side attachment portion is brought into contact with the outlet gap of the nozzle base, and the molten resin is injected into the cavity from the outlet gap, thereby attaching the small-diameter side. After forming the part, the molten resin is extruded through the outlet gap and the drawing device is separated to form a cylindrical parison, and then the uppermost part of the nozzle base is replaced with a blow mold to blow the bellows part. There has been proposed a method for manufacturing a tripod type joint as described above by molding and injection-molding the large-diameter side attachment portion with a lower nozzle cap.

However, in the method described in Patent Document 2, the cavity for molding the large-diameter side mounting portion which has the highest dimensional accuracy and is difficult to be molded because the dimension is the largest is the small-diameter side mounting portion. It is used as a flow path for molten resin during the injection molding and extrusion of the parison. Therefore, it is necessary to keep this cavity part at a high temperature when using it as a flow path for molten resin, and to cool it at the time of injection molding, and there is a problem that temperature control is complicated and it is difficult to ensure high dimensional accuracy. .
Japanese Patent Laid-Open No. 6-234150 Japanese Unexamined Patent Publication No. 2002-361715

  The present invention has been made in view of the above points, and a joint manufacturing method capable of accurately manufacturing a joint boot having a large-diameter side mounting portion in which an outer peripheral surface and an inner peripheral surface are irregularly shaped, And it aims at providing the heating apparatus used for this method.

  The method of the present invention includes a cylindrical large-diameter side mounting portion that is attached by fitting a plurality of convex portions projecting from the inner peripheral portion to the concave portion of the outer case, a small-diameter side mounting portion that is attached to the shaft, The joint boot which consists of a bellows part which connects, and includes the following steps.

(1) A cylindrical parison including a first portion corresponding to the large-diameter side mounting portion, a second portion corresponding to the small-diameter side mounting portion, and a third portion connecting the first portion and the second portion. Molding with molding material,
(2) Of the first part, the second part, and the third part, heating only the third part to a set temperature with a heating device;
(3) Thereafter, the step of covering the third part with an outer mold, injecting gas onto the inner peripheral surface of the third part, and pressing the third part against the outer mold to form the bellows part.

  According to this means, the large-diameter side mounting portion and the small-diameter side mounting portion are formed into a final product shape with high dimensional accuracy at the time of parison molding, and the bellows portion is final product by subsequent blow molding. Since it can be formed into a shape, even if the large-diameter side mounting portion and the small-diameter side mounting portion have different shapes, it can be accurately molded.

  Further, according to this means, only the third part for forming the bellows part is heated to the set temperature by the heating device, and then the third part is blow-molded, so that the third part in the state before the blow-molding is performed. Variations in temperature distribution can be made difficult to occur. Here, even if the temperature distribution of the parison varies when the cylindrical parison is molded in the parison molding process, if the blow molding is performed without such heating, a high temperature part is obtained. It swells well and it becomes difficult to swell the part where the temperature is low, and it becomes difficult to form the thickness of the bellows part uniformly. On the other hand, according to the present invention, it is possible to make the temperature distribution of the third portion less susceptible to variation due to the heating, and therefore the third portion can be uniformly expanded when the third portion is blow-molded. Therefore, the thickness of the bellows portion can be formed uniformly.

The manufacturing method according to claim 1 , wherein in the above method, the convex portion has an arcuate shape that constitutes a part of the outer peripheral surface of the inner wall portion projecting radially inward and the large-diameter side mounting portion. An outer wall portion, a radially extending central support wall connecting the inner wall portion and the outer wall portion at the center in the circumferential direction thereof, and left and right connecting the inner wall portion and the outer wall portion on both sides of the central support wall and a side supporting wall, the side support walls characterized that you have inclined so as to approach to the central support wall as outward.

  Thus, the convex portion is provided with a hollow portion as a hollow hole between the central support wall and the side support wall and on both sides of the side support wall. Therefore, the molding material can be cooled more quickly than the case where the convex part is formed of a solid thick part, and the occurrence of sink marks due to shrinkage after molding can be prevented.

  In addition, since the side support walls are inclined so as to approach the center support wall toward the outside, the following effects can be achieved. That is, when the side support wall is arranged in parallel to the center support wall, the outer side hole of the side support wall becomes small, so that it is difficult to remove the core, as described above. By inclining toward the center support wall side, the cross-sectional area of the outside hole on the side support wall can be ensured, and the demoldability of the core can be ensured.

  Furthermore, by tilting the side support wall as described above, the side support wall that supports the outer surface of the inner wall portion can be coupled to the inner wall portion at an angle close to perpendicular. Therefore, when the large-diameter side mounting portion is fastened and fixed, the surface pressure exerted by the inner wall portion on the outer case can be made uniform in the circumferential direction, and the sealing performance at the convex portion can be improved. From such a viewpoint, it is preferable that the side support wall is coupled substantially perpendicularly to the inner wall portion, and more specifically, the angle of the side support wall with respect to the inner wall portion is within a range of 70 ° to 110 °. It is preferable that

  In this case, it is preferable that the side support wall is coupled to the inner wall portion at an intermediate position between the connecting portion of the inner wall portion with the central support wall and the base portion to the outer wall portion. The weakest part on both sides of the connecting part with the central support wall in the inner wall part is the midpoint between the connecting part and the base part to the outer wall part, so the inner wall part is supported by the side support wall at this position. If reinforced as described above, it is more effective for uniforming the surface pressure to the outer case by the inner wall portion.

The manufacturing method according to claim 3 , wherein in the above method, the first portion is fitted concentrically to the lower fitting portion of the support, and the second portion is concentric to the upper fitting portion of the support. The parison is supported by the support so that the third portion is concentrically surrounded by a space between the upper and lower intermediate portions of the support, and the support is supported by the support. characterized by heating the third part while rotating about the axis of the body from the outward radial direction side.

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

  In the manufacturing method of the present invention, a cover member having a cylindrical shape that surrounds the parison from the first portion to the second portion in a concentric manner, and for heating the portion covering the third portion. A cover member having an opening may be placed on the parison to heat the third portion.

  According to this means, the third portion is heated through the opening provided in the cover member. However, since the first portion and the second portion are covered by the cover member, they are not easily heated by the heating device. Therefore, it is possible to suppress deformation of the large-diameter side mounting portion and the small-diameter side mounting portion due to the heating of the first portion and the second portion.

  In the manufacturing method of the present invention described above, after the heating of the third portion is completed, the parison is covered with the outer mold while being supported by the support, and the gas is discharged from an injection port provided on the support. May be injected.

  According to this means, since the gas is injected from the injection port provided in the support, after the heating of the third portion is completed, it is necessary to newly support the parison on the member dedicated to blow molding provided with the injection port. In this case, the labor required for blow molding can be reduced.

  A heating device according to the present invention is a heating device used in the above-described method for manufacturing a joint boot according to the present invention, and a plurality of the supports are arranged on the lower conveyor at intervals in the conveying direction, A rotation drive mechanism is provided between the support and the lower conveyor to rotate the support around the axis, and a plurality of the cover members are provided on the upper conveyor facing the lower conveyor, with an interval in the conveying direction. A lifting mechanism that supports the suspension and raises and lowers the cover member between each cover member and the upper conveyor is provided, and heaters are arranged on both lateral outer sides between the lower conveyor and the upper conveyor. It is.

  According to this configuration, the following effects can be achieved. That is, the first part is fitted concentrically to the lower fitting part of the support, the second part is fitted concentrically to the upper fitting part of the support, and the third part is made of the support. The parison is supported by the support so that the upper and lower intermediate portions are concentrically surrounded with a gap. Then, the cover member suspended and supported by the upper conveyor is lowered by driving the lifting mechanism to cover the parison. Then, the third conveyor is moved between the lower conveyor and the upper conveyor through the opening provided in the cover member while conveying and driving the upper conveyor and the lower conveyor and rotating the support around the axis of the support. Heat with heaters on both sides outside.

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

  As described above, according to the present invention, it is possible to accurately manufacture a joint boot having a large-diameter side mounting portion whose outer peripheral surface and inner peripheral surface are different shapes, and the bellows portion is molded. Since only the three portions are heated to a set temperature with a heating device, and then the third portion is blow-molded, the thickness of the bellows portion can be uniformly formed.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIGS. 10 and 11 show a triport type constant velocity joint of an automobile, and FIGS. 4 and 5 show a joint boot made of a 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 mounting portion 2 that is externally fitted to the outer case 1, a cylindrical small-diameter side mounting 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 three convex portions 7 projecting radially inward are provided on the inner peripheral portion 2b of the large-diameter side mounting portion 2. The three convex portions 7 are provided so as to be separately fitted to the three concave portions 8 formed on the outer peripheral portion of the outer case 1 by being uniformly distributed every 120 degrees in the circumferential direction.

  The convex portion 7 includes an inner wall portion 71 projecting inward in the radial direction and an arc-shaped outer wall portion 72 constituting a part of the outer peripheral surface 2a of the large-diameter side attachment portion 2, and these inner wall portions A central support wall 73 that connects the wall portions 71 and 72 at the center in the circumferential direction to a hollow portion between the portion 71 and the outer wall portion 72, and a pair of left and right sides that connect the wall portions 71 and 72 on the left and right sides thereof. Side support walls 74, 74 are provided.

  The outer wall portion 72 is an arc-shaped wall portion having a substantially constant thickness in the circumferential direction so as to be integrated with the arc-shaped wall portion 76 interposed between the convex portions 7 to form a single cylindrical body. It is configured. The inner wall portion 71 is a wall portion having a substantially constant thickness that is formed to protrude in a curved surface shape from the inner peripheral surface of the cylindrical body toward the inside in the radial direction.

  As shown in FIG. 6, the central support wall 73 is a radially extending wall portion that supports the inner wall portion 71 with respect to the outer wall portion 72, and has the highest inward projection height of the inner wall portion 71. It is provided at the center in the large circumferential direction.

  The side support wall 74 is a wall portion that supports the inner wall portion 71 with respect to the outer wall portion 72, and is not parallel to the central support wall 73 that is provided radially from the center of the large-diameter side mounting portion 2. The outer side is inclined so as to approach the central support wall 73. More specifically, the side support wall 74 is configured so that the inner wall portion 71 is supported by the central support wall 73 and the side support walls 74 and 74 at equal intervals in the circumferential direction. The inner wall portion 71 is supported at an intermediate position between the base portion 71a and the connecting portion 71b of the central support wall, that is, connected to the inner wall portion 71 at the intermediate position. In addition, the connecting portion is provided so as to be substantially perpendicular to the inner wall portion 71 so as to be inclined toward the center, that is, closer to the central support wall 73 as it goes outward from the connecting portion. Here, it is preferable that the coupling angle θ of the side support wall 74 with respect to the inner wall portion 71 is substantially vertical. Specifically, the coupling angle θ is within a range of 70 ° to 110 ° (that is, 90 ° ± 20 °). It is preferable that it exists, More preferably, it exists in the range of 80 degrees-100 degrees. The coupling angle θ is an angle formed by the center line N of the side support wall 74 and the tangent line Q on the inner peripheral surface of the inner wall 71 that intersects the center line N.

  With this configuration, the convex portion 7 is provided with a plurality of hollow holes 75 that are a plurality of hollow portions arranged in the circumferential direction. Specifically, the convex portion 7 is formed with two pairs of bottomed hollow holes 75a, 75b, 75c, and 75d that are open on the end face of the large-diameter side attachment portion 2 and that are symmetric about the circumferential center line L. The depth of each of the hollow holes 75a to 75d is set to be the same. The pair of inner hollow holes 75b and 75c partitioned by the central support wall 73 have a trapezoidal cross-sectional shape in which the outer peripheral surface 2a side of the large-diameter side attachment portion 2 is narrowed, and the pair of outer meats The punched holes 75a and 75d have a triangular cross section with an apex angle directed radially inward.

  As shown in FIG. 4, a fixing recess 60 extending in the circumferential direction for receiving a ring-shaped band 9 (see FIG. 10) as a fastening member is provided on the outer peripheral surface 2 a of the large-diameter side mounting portion 2. Is provided. Further, two ribs 61 extending in the circumferential direction are provided on the inner peripheral surface of the large-diameter side attachment portion 2. Similarly, in the small-diameter side mounting portion 4, a fixing recess 62 extending in the circumferential direction for receiving the ring-shaped band 9 that is a fastening member is provided on the outer peripheral surface thereof, and the inner peripheral surface thereof is also provided. Are provided with two ribs 63 extending in the circumferential direction.

  This joint boot is manufactured 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, the first portion 12 corresponding to the large diameter side mounting portion 2, the second portion 13 corresponding to the small diameter side mounting portion 4, A cylindrical parison 15 including the third portion 14 corresponding to the bellows portion 5 is injection-molded.

  In that case, the 1st part 12 is shape | molded as the large diameter side attaching part 2 in the cavity of the shaping | molding apparatus A, ie, is injection-molded to the final product shape of the large diameter side attaching part 2. FIG. Accordingly, the first portion 12 is formed in a shape in which the outer peripheral surface has a circular cross section and includes a plurality of the convex portions 7 on the inner peripheral portion. 75d is molded. The fixing recess 60 is formed on the outer peripheral surface, and two ribs 61 are formed on the inner peripheral surface.

  Further, the second portion 13 is molded as the small diameter side mounting portion 4 in the cavity of the molding apparatus A, that is, injection molded into the final product shape of the small diameter side mounting portion 4. At this time, the second portion 13 is formed in a cylindrical shape having a smaller diameter than the first portion 12, the fixing recess 62 is formed on the outer peripheral surface, and the two ribs 63 are formed on the inner peripheral surface. . Further, the opening surface at the upper end of the second portion 13 is closed after the injection molding, and the closed portion 13a is cut off after the blow molding in this embodiment.

  On the other hand, the third portion 14 is not a bellows shape corresponding to the final product shape, but is a parison portion interposed between the first portion 12 and the second portion 13, and is a tapered tube connecting the two. Injection molded into a shape. That is, the third portion 14 is formed in a tapered shape in which the diameter gradually decreases from the large-diameter attachment portion 2 toward the small-diameter attachment portion 4.

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

  As shown in FIGS. 7 to 9, 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. A rotation drive mechanism M that rotates the support 16 around the axis O of the support 16 is provided between the lower conveyor 17 and the lower conveyor 17.

  The support 16 is surrounded by a support base 19 on the lower end side, a lower fitting portion 20 having a smaller diameter than that of the first fitting portion 12 and fitting the first portion 12 concentrically, and the third portion 14 with a space therebetween. It consists of a columnar upper and lower intermediate portion 21 and an upper fitting portion 22 that is provided at the upper end of the upper and lower intermediate portion 21 and externally fits the second portion 13 concentrically.

  A plurality of cylindrical 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 a cover is provided between each cover member 24 and the upper conveyor 23. A cylinder 25 (equivalent to an elevating mechanism) for raising and lowering the member 24 is provided, and a pair of long far-infrared heaters 53 are separately arranged on both lateral outer sides between the lower conveyor 17 and the upper conveyor 23. .

  The cover member 24 forms a cylindrical shape that surrounds the parison 15 held on the support 16 in a concentric manner over the entire height direction, that is, from the first portion 12 to the second portion 13. Specifically, a large-diameter cylindrical portion 24a that surrounds the outer periphery of the first portion 12 and a small-diameter cylindrical portion 24b that surrounds the outer periphery of the second portion 13 and the third portion 14 are connected via a step portion 24c. It has a stepped cylindrical shape and has a top plate portion 24d that closes its upper end. The cover member 24 is provided in any part of the parison 15 in a non-contact manner, thereby preventing a contact mark during heating from remaining on the surface of the parison 15.

  Further, the cover member 24 includes a heating opening 27 at a location covering the third portion 14. The opening portions 27 are provided at two locations facing the diameter direction of the cover member 24 so as to face the pair of heaters 53, 53 provided on both lateral sides of the conveyors 17, 23, respectively. The height of the opening 27 is set so that the lower end 27a is set at the boundary between the first portion 12 and the third portion 14 so that only the third portion 14 is irradiated with heat rays from the heater, that is, far infrared rays, and the upper end 27b. Is set at the boundary between the second portion 13 and the third portion 14. As a result, the cover member 24 does not receive far infrared rays from the heater 53 on the first portion 12 and the second portion 13 and therefore is not heated, and the height of the third portion 14 is high. The parison 15 is covered so that far infrared rays from the heater 53 are irradiated over the entire direction.

With the above structure,
(1) With respect to the support body 16 provided on the lower conveyor 17, the first portion 12 is fitted concentrically to the lower fitting portion 20 of the support body 16, and the second portion 13 is the upper side of the support body 16. The parison 15 is supported by the support 16 so that the third portion 14 is concentrically surrounded by the fitting portion 22 and is concentrically surrounded by the upper and lower intermediate portions 21 of the support 16. (See FIG. 7).

  (2) The cover member 24 suspended and supported by the upper conveyor 23 is lowered by driving the cylinder 25 to extend, and covers the entire parison 15 supported by the support 16 (see FIG. 2).

  (3) Both sides outward between the lower conveyor 17 and the upper conveyor 23 while the upper conveyor 23 and the lower conveyor 17 are conveyed and driven, and the support 16 is rotated around its axis O. The heater 53 on the side is heated. In this case, the parison 15 rotates together with the support 16, but the cover member 24 does not rotate, and the third portion 14 is heated over the entire circumference through the opening 27 facing the heater 53 (FIGS. 2, 8, 9).

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

[Blow molding process]
After the heating of the third portion 14 is completed, as shown in FIG. 3, the parison 15 is supported by the support body 16 and the mold surface is covered with the outer mold 51 having the bellows shape, and the injection port ( A gas bellows portion 5 is formed by injecting gas from the not-shown gas to the inner peripheral surface of the third portion 14 and pressing the third portion 14 against the outer mold 51.

  At this time, since the upper end opening surface of the second portion 13 is closed by the closing portion 13a, gas sealing is not necessary at the upper end portion of the parison 15, and only the first portion 12 at the lower end portion needs to be sealed. For example, when the parison 15 is attached to the support body 16, the seal at the first portion 12 is obtained by fitting the inner peripheral surface 12 a of the first portion 12 in close contact with the outer peripheral surface of the lower fitting portion 20. Alternatively, after the support body 16 supporting the parison 15 is closed with a laterally split outer mold 51 so as to cover from the side, the support body 16 is shifted upward to open the first portion 12. The end surface 12 b may be pressed against the upper surface of the support base 19.

  After the bellows portion 5 is blow-molded in this way, the joint boot is obtained by cutting the closed portion 13a at the upper end opening surface of the second portion 13.

  In the present embodiment configured as described above, the large-diameter side attaching portion 2 and the small-diameter side attaching portion 4 are made into a final product shape with high dimensional accuracy by injection molding at the time of parison molding, and the bellows portion 5 Since the final product shape is formed by blow molding, not only the small-diameter side attachment portion 4 but also the large-diameter side attachment portion 2 whose inner peripheral portion shape is greatly different from the outer peripheral portion can be accurately formed. .

  Moreover, since only the 3rd part 14 which shape | molds the bellows part 5 is heated to preset temperature with the heating apparatus B, and this 3rd part 14 is blow-molded after that, the temperature of the 3rd part 14 in the state before blow-molding The distribution is less likely to vary, so that the third portion 14 can be uniformly expanded when blow-molded, and therefore the thickness of the bellows portion 5 can be uniformly molded.

  In addition, by providing the above-described unique hollow holes 75a to 75d in the convex portion 7, the large-diameter side attachment portion 2 can be easily formed into a desired shape with high accuracy, and the adhesion of the large-diameter side attachment portion 2 to the outer case is improved. Can be improved. Further, since the side support walls 74 are inclined so as to approach the center support wall 73 toward the outer side, the cross-sectional area of the outer lightening holes 75a and 75d is secured, and the core can be removed from the mold. Can be secured. Further, since the side support wall 74 can be coupled to the inner wall portion 71 at an angle close to vertical, the surface pressure exerted on the outer case by the inner wall portion 71 when the large-diameter side mounting portion 2 is fastened and fixed. Can be made uniform in the circumferential direction, and the sealing performance at the convex portion 7 can be improved.

  Furthermore, by applying the specific heating device B and the heating method described above, the temperature distribution of the third portion 14 can be made less likely to vary, and the efficiency of the heating operation can be increased. The time and effort required for blow molding can be reduced.

  Further, in the case of this heating device B, since the individual cover member 24 is put on the parison 15 transported on the conveyor 17, it is possible to change the cover member according to the product of the joint boot. It can be easily applied to various types of joint boots. Instead of such individual cover members 24, a wall-shaped cover member extending along the conveyor 17 may be provided so as to face the heater 53, and only the third portion 14 may be heated.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for manufacturing a joint boot used for a constant velocity joint of an automobile.

Diagram showing the parison molding process Diagram showing the heating process Diagram showing blow molding process Partial cutaway view showing joint boots The figure which shows the large diameter side attachment part of the joint boot Sectional view of the convex part at the large diameter side mounting part of the joint boot 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 part, 13 ... 2nd part, DESCRIPTION OF SYMBOLS 14 ... 3rd part, 15 ... Parison, 16 ... Support body, 17 ... Lower conveyor, 20 ... Lower fitting part, 21 ... Upper and lower intermediate part, 22 ... Upper fitting part, 23 ... Upper conveyor, 24 ... Cover Members, 25 ... elevating mechanism, 51 ... outer mold, 53 ... heater, 55 ... inner peripheral part, 71 ... inner wall part, 72 ... outer wall part, 73 ... central support wall, 74 ... side support wall, 75a-75d ... Opening hole, B ... heating device, O ... axis of support, M ... rotational drive mechanism

Claims (6)

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 mounted on the shaft, and a bellows portion that connects these A joint boot comprising: an inner wall portion projecting in a curved shape radially inward in the convex portion, and an arc shape constituting a part of an outer peripheral surface of the large diameter side attachment portion An outer wall portion, a radially extending central support wall connecting the inner wall portion and the outer wall portion at the center in the circumferential direction thereof, and connecting the inner wall portion and the outer wall portion on both sides of the central support wall. A joint boot that includes left and right side support walls and is inclined so that the side support walls are closer to the center support wall toward the outside ,
A cylindrical parison comprising: a first portion corresponding to the large-diameter side attachment portion; a second portion corresponding to the small-diameter side attachment portion; and a third portion connecting the first portion and the second portion. Molded with molding material,
Of the first part, the second part and the third part, only the third part is heated to a set temperature with a heating device,
Thereafter, the third part is covered with an outer mold, a gas is injected onto the inner peripheral surface of the third part, and the third part is pressed against the outer mold to mold the bellows part. The side support wall is coupled to the inner wall portion at an intermediate position between a connection portion of the inner wall portion with the central support wall and a base portion to the outer wall portion. A method for producing a joint boot according to 1 . 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 mounted on the shaft, and a bellows portion that connects these A method of manufacturing a joint boot comprising:
A cylindrical parison comprising: a first portion corresponding to the large-diameter side attachment portion; a second portion corresponding to the small-diameter side attachment portion; and a third portion connecting the first portion and the second portion. Molded with molding material,
The first part is fitted concentrically to the lower fitting part of the support, the second part is fitted concentrically to the upper fitting part of the support, and the third part is supported. The parison is supported by the support so that the upper and lower middle parts of the body are concentrically surrounded with a gap, and the third part is rotated while the support is rotated around the axis of the support. Of the first portion, the second portion, and the third portion, only the third portion is heated to a set temperature with a heating device.
Thereafter, the third part is covered with an outer mold, gas is injected onto the inner peripheral surface of the third part, and the third part is pressed against the outer mold to form the bellows part. A cover member having a cylindrical shape that concentrically surrounds the parison from the first portion to the second portion, the cover member having an opening for heating at a location covering the third portion. covered by the third part joint boot manufacturing method according to claim 3, wherein for heating the. 5. The joint boot according to claim 4 , wherein after the heating of the third 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. Production method. A heating device used in the method for manufacturing a joint boot according to claim 4 or 5 ,
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 to rotate the support bodies around the axis. A plurality of the cover members are supported on the upper conveyor facing the lower conveyor, suspended and supported at intervals in the conveying direction, and an elevating mechanism for raising and lowering the cover member between each cover member and the upper conveyor is provided, The heating apparatus which has arrange | positioned the heater on the both sides outward side between the said lower side conveyor and an upper side conveyor.

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