JP5207634B2 - Constant velocity joint - Google Patents

Description

  The present invention relates to a constant velocity joint used for propeller shafts and drive shafts of automobiles and various industrial machines, and more particularly, to a constant velocity joint that prevents excessive deformation of the boot by allowing a comfortable ventilation effect inside and outside the boot. .

  Constant velocity joints used in automobiles and the like prevent dust from entering the inside of the joint from the outside and prevent grease inside the joint from leaking to the outside as shown in FIG. A boot 2 is mounted on the shaft 1 side. FIG. 1 (A) shows an embodiment of the present invention, which is used for convenience in explaining a conventional constant velocity joint. The boot 2 is generally composed of a rubber material or a flexible resin material. In a constant velocity joint attached to a shaft 1 having a small operating angle and rotating at a high speed, such as a propeller shaft of an automobile, a rigid cylindrical metal ring 3 is used to suppress expansion of the boot 2 due to centrifugal force during high speed rotation. Are often integrated into the boot 2. The metal ring 3 is fixed by caulking or bolting to the outer diameter surface of the outer ring 4. The shape of the boot 2 is not limited to that shown in FIG.

  The boot 2 has a large-diameter mounting portion 2a that is crimped and joined to the opening end of the metal ring 3, a small-diameter mounting portion 2b that is press-fitted into the shaft 1 and fastened and fixed by the boot band 5, and a large-diameter mounting portion 2a. It is composed of a bent portion 2c having a curved cross section that connects the small diameter attaching portion 2b. An inner ring 6 is fixed to the end of the shaft 1 extending into the boot 2, allowing the shaft 1 to the inner ring 6 to swing between the outer ring 4 and the inner ring 6, and transmitting torque between the inner and outer rings. A plurality of balls 7 and a cage 8 for holding each ball 7 are disposed. The outer ring 4 is fixed to the mounting flange portion 24a on the vehicle side by bolts or the like.

  In such a constant velocity joint boot 2, especially in the case of a constant velocity joint for power transmission of an automobile, the internal temperature of the joint increases or the temperature of the peripheral portion of the joint increases depending on the driving state of the automobile. As the temperature rises, the joint itself also rises in temperature, and the pressure inside the boot 2 rises, or conversely, the pressure is greatly fluctuated due to subsequent cooling to negative pressure. For this reason, the boot 2 may be deformed excessively, and the durability of the boot 2 may be extremely reduced. This type of constant velocity joint includes a slide type in which the inner ring and the outer ring can move relative to each other in the axial direction (plunging) and a fixed type that does not plunge, but the deformation of the boot 2 due to pressure is a common phenomenon. .

In order to solve the problem of deformation due to the pressure of the boot 2, as shown in FIGS. 7 to 9, a vent hole 13 and a lip portion 14 are provided in the mounting portion on the shaft 1 side of the boot 2, and the tip of the lip portion 14 is provided. By forming a plurality of protruding protrusions 15 on the shaft 1 side in a discontinuous manner, the lip portion 14 is opened to the outside when the internal pressure is increased, and the lip portion 14 is closed when the negative pressure is increased, and the outside air is released from a narrow gap between the protrusions 15. By adopting a structure in which the pressure is applied, the pressure applied to the boot 2 is reduced as much as possible to increase the life of the boot 2 (see Patent Document 1).
JP-A-8-28704

  In the case of Patent Document 1, although excessive deformation of the boot 2 is alleviated to some extent, since there is a gap between the outer peripheral surface of the shaft 1, the ingress of dust and muddy water from the outside through this gap, or grease enclosed inside It is not possible to reliably prevent leakage of the water.

  In view of such circumstances, an object of the present invention is to provide a constant velocity joint that enables the flow of gas inside and outside the boot in a state in which the flow of liquid is blocked.

The invention according to claim 1 allows the inner ring to swing between the outer ring, the inner ring disposed so as to be swingable relative to the outer ring, a shaft having one end connected to the inner ring, and the inner and outer rings. And a plurality of torque transmission members that engage with the inner and outer rings to transmit torque between the inner and outer rings, and a seal structure that hermetically seals the left and right openings of the outer ring, and at least the seal structure around the shaft In a constant velocity joint composed of a rubber or resin boot that allows the shaft to swing, a part of the seal structure allows air to pass but prevents liquid from passing , and is a polymer resin film composed of breathable film obtained by generating the molecular arrangement direction substantially parallel striped crazes, in response to a request aeration of the constant velocity joint, the spacing between Craze mutual said breathable film, clay The width, of the proportion of penetrating crazes is obtained by changing at least one.

The breathable film formed by generating craze allows passage of air inside and outside of the constant velocity joint, so that it is possible to prevent a pressure difference from occurring inside and outside the boot. As a result, it is possible to prevent a decrease in boot life due to excessive deformation of the boot. In addition, since the air permeable film prevents the passage of liquid, it is possible to prevent the intrusion of dust or muddy water into the constant velocity joint and the leakage of the grease inside the constant velocity joint to the outside. Moreover, since the air permeable film formed by producing crazes can be easily produced, it leads to a reduction in production cost. Further, it is possible to easily adjust the air permeability by changing at least one of the interval between crazes, the width of crazes, and the ratio of crazes that penetrated.

According to a second aspect of the present invention, in the constant velocity joint according to the first aspect, a vent hole is formed in a central portion of the seal structure that hermetically seals the opening of the outer ring on the side opposite to the shaft, and the vent hole is provided. it is obtained by closed with the breathable film.

  By forming a vent hole in the center of the seal structure in this way, a lubricant such as grease enclosed in the joint during the rotation of the constant velocity joint is unevenly distributed on the outer diameter side inside the joint by centrifugal force. Therefore, the adhesion of grease can be made very small near the vent. Therefore, it is possible to avoid the breathable film disposed in the vent from being covered with the grease, and the breathability of the breathable film can be maintained well.

According to a third aspect of the present invention, in the constant velocity joint according to the first aspect, the air vent is provided at a position that is decentered by 1 to 20 mm from a rotation center of the seal structure that hermetically seals the opening of the outer ring opposite to the shaft. formed, the vent, in which closed with the breathable film.

  Thereby, even if the grease enclosed in the constant velocity joint adheres to the air permeable film, the adhered grease can be naturally removed from the air permeable film by the centrifugal force generated by the rotation of the constant velocity joint. Further, the amount of eccentricity at the position where the air vent is formed is not too large, and there is no possibility that the air permeable film is immersed in the grease moved by the centrifugal force.

According to a fourth aspect of the present invention, in the constant velocity joint according to the second or third aspect, at least the central portion of the seal structure that hermetically seals the opening of the outer ring on the side opposite to the shaft is provided with a double outer wall and inner wall. together comprise a wall, the form internal to the separation zone extending in a radial direction of the double wall, to form a first vent in the center of the outer wall, the first vent, the It is closed with a breathable film, forms a second vent in the center of the inner wall, and forms a return port communicating with the gas-liquid separation space radially outward of the second vent on the inner wall. is there.

  Even if the grease inside the constant velocity joint enters the gas-liquid separation space from the second vent on the inner wall, the grease is shaken off radially outward by the centrifugal force generated by the rotation of the constant velocity joint, and the constant velocity from the return port It can be returned to the inside of the joint. By doing so, it is possible to more effectively prevent the grease from adhering to the air permeable film and to reliably prevent the grease from leaking from the air vent.

  According to a fifth aspect of the present invention, in the constant velocity joint according to any one of the first to fourth aspects, the outer ring has a vehicle mounting surface that can be mounted on a mounting flange portion of a vehicle, and the vehicle mounting surface and the vehicle A gap is partially provided between the mounting flange portion and the gap communicated with the outside of the vent or the first vent.

  This ensures the entry and exit of air inside and outside the constant velocity joint through the gap.

According to a sixth aspect of the present invention, in the constant velocity joint according to the first aspect, a third vent hole extending in an axial direction is formed in an attachment portion of the boot that is in contact with the outer peripheral surface of the shaft, and the third vent hole is wherein those of closing breathable film.

  Since the third vent is formed in the attachment portion, there is no possibility that the breathable film disposed in the third vent is immersed in the grease moved by the centrifugal force due to the rotation of the constant velocity joint. Further, the attachment portion is a portion that is not easily affected by the boot durability due to the formation of the third vent.

  A seventh aspect of the present invention is the constant velocity joint according to the sixth aspect, wherein the third vent is a single or a plurality of pores formed along the axial direction in the attachment portion between the boot and the shaft. is there.

  By changing the number of third vents, the amount of air flowing in and out of the constant velocity joint can be adjusted.

According to an eighth aspect of the present invention, in the constant velocity joint according to the first aspect, in the rubber or resin boot that is the seal structure around the shaft, the mounting portion of the boot that is in contact with the outer peripheral surface of the shaft. the boot oblique section adjacent to form a single or plurality of fourth vent, the fourth vent, in which closed with the breathable film.

  Since the fourth ventilation hole is formed in the oblique side of the boot adjacent to the mounting part of the boot in contact with the outer peripheral surface of the shaft, the breathable film disposed in the fourth ventilation hole is centrifuged by rotation of the constant velocity joint. There is no risk of being immersed in grease moved by force. In addition, the oblique side portion is a portion that is not easily affected by the durability of the boot due to the formation of the fourth vent.

A ninth aspect of the present invention is the constant velocity joint according to any one of the first to eighth aspects, wherein the additive layer is formed on the craze.

  Depending on the type of additive, the breathable film can exhibit various functions. For example, the additive layer can contain a stabilizer to improve the durability of the breathable film, or the additive layer can contain a plasticizer to improve the flexibility of the breathable film.

A tenth aspect of the present invention is the constant velocity joint according to any one of the first to ninth aspects, wherein the polymer resin film is bent substantially in parallel with the molecular orientation direction to form a fold line, and the bending is performed. In addition, while the both sides of the polymer resin film are pressed by a pressing member, they are pulled in a direction perpendicular to the fold line to produce the striped craze substantially parallel to the molecular orientation direction.

  Thus, crazing can be easily generated in the polymer resin film, and the manufacturing cost can be reduced.

The invention according to claim 11 is the constant velocity joint according to any one of claims 1 to 9 , wherein an acute angle corner of the pressing body is formed on one surface of the polymer resin film in a molecular orientation direction of the polymer resin film. The molecular orientation is formed by pulling the polymer resin film in a direction orthogonal to the bend line while pressing the corners of the pressing body against the polymer resin film. The crazes in the form of stripes are generated substantially parallel to the direction.

  Thus, crazing can be easily generated in the polymer resin film, and the manufacturing cost can be reduced.

  According to the constant velocity joint of the present invention, the air permeability is secured in a state where the passage of the liquid is blocked by the air permeable film formed by craze, so that a pressure difference does not occur inside and outside the boot. As a result, it is possible to prevent a decrease in life due to excessive deformation of the boot. Moreover, since this air-permeable film prevents the passage of liquid, external dust and muddy water do not enter the boot, and conversely, the grease in the boot does not leak to the outside. Moreover, since the air permeable film formed by producing crazes can be easily produced, it leads to a reduction in production cost.

  Hereinafter, first to fourth embodiments in which the present invention is applied to a constant velocity joint for a propeller shaft of an automobile will be described with reference to the accompanying drawings. However, the application is not limited to this, and it can also be applied to a constant velocity joint used for a drive shaft of an automobile and various industrial machines. The constant velocity joints mentioned here include fixed constant velocity joints that allow only angular displacement, and sliding types such as cross groove type, double offset type, tripod type constant velocity joints that allow angular displacement and axial displacement, etc. There is a quick joint.

A first embodiment of the present invention will be described.
As shown in FIG. 1A, one end of a boot 2 is attached to the outer peripheral surface of the first shaft 1 (right side of the drawing) connected to the inner ring 6 of the constant velocity joint. The boot 2 is made of rubber or flexible. It is made of resin material. In order to suppress the expansion of the boot 2 due to the centrifugal force during high-speed rotation of the constant velocity joint, the other end of the boot 2 is integrated with a rigid cylindrical metal ring 3, and the metal ring 3 is connected to the outer diameter of the outer ring 4. A plurality of bolts 9 are fixed in close contact with the surface.

  The boot 2 is press-fitted into a large-diameter mounting portion 2 a that is caulked and joined to the opening end of the metal ring 3 and an annular concave step portion formed on the outer periphery of the shaft 1 with a slightly small diameter, and is tightened with a boot band 5. It is composed of a fixed small-diameter mounting portion 2b and a bent portion 2c having a curved cross section that connects the large-diameter mounting portion 2a and the small-diameter mounting portion 2b.

  The end portion of the shaft 1 extending into the boot 2 is serrated to the inner diameter surface of the inner ring 6, and a retaining ring 19 for retaining the inner ring 6 is formed on the outer diameter surface of the tip portion of the shaft 1 protruding from the inner ring 6. It is mated. A plurality of balls 7 (torque transmission members) that allow the shaft 1 to the inner ring 6 to swing between the outer ring 4 and the inner ring 6 and enable torque transmission between the inner and outer rings 6 and 4, and each ball A cage 8 that holds 7 is disposed. A first groove 20 for receiving the ball 7 is formed on the outer diameter surface of the inner ring 6 with an angle of inclination with respect to the axial direction or the axial direction. The ball 7 and the inner ring 6 are engaged with each other in the circumferential direction by the first groove 20, and the ball 7 is movable along the first groove 20.

  The cage 8 is a thin annular body located on the outer periphery of the inner ring 6, and its cross section has a convex shape (the outer peripheral surface is a spherical surface) outward in the radial direction. The inner peripheral surface of the cage 8 is loosely fitted to the outer diameter surface of the inner ring 6, but the spherical outer peripheral surface of the cage 8 is slidably fitted to the inner diameter surface of the outer ring 4 by line contact. Yes. The cage 8 is formed with a pocket 21 in contact with the equator portion of the ball 7, and the ball 7 slides on the inner peripheral surface of the pocket 21 when the shaft 1 swings.

  On the inner diameter surface of the outer ring 4, a second groove 22 is formed that fits into the head (high latitude side portion) of the ball 7 protruding radially outward from the pocket 21 of the cage 8. The ball 7 and the outer ring 4 are engaged with each other in the circumferential direction by the second groove 22, and the ball 7 is movable along the second groove 22.

  The opening on the tip side of the shaft 1 of the outer ring 4 is entirely covered with a seal plate 23. The seal plate 23 is formed of a sheet metal in a deep dish shape, and the peripheral portion of the seal plate 23 is closely fixed to the outer diameter surface of the outer ring 4 with the bottom thereof facing the second shaft 24. The outer ring 4 of the constant velocity joint is fastened to the mounting flange portion 24 a of the second shaft 24 with a plurality of bolts 9.

  As can be seen from the above description, the left and right openings of the outer ring 4 are hermetically sealed by the boot 2, the metal ring 3 and the seal plate 23. That is, the “seal structure” is constituted by the boot 2, the metal ring 3 and the seal plate 23.

  A small vent 25 is formed in the central portion of the seal plate 23, that is, on the extension of the axis of the first shaft 1 in the state where the operating angle is 0 °, or on the extension of the axis of the second shaft 24. The size and shape of the vent 25 are not particularly limited, but a size and shape (for example, a circular hole having a diameter of 5 mm or less) necessary for a slight amount of air to enter and exit are sufficient, and need not be made too large. A breathable film 26a having an arbitrary shape such as a disk is fixed to the outside of the vent 25 by any means such as adhesion or caulking. This breathable film 26a is formed by forming crazes on a polymer resin film, and has the property of allowing the passage of air but preventing the passage of liquid.

  The term “craze” as used herein refers to a region having both a surface craze appearing on the surface of the polymer resin film and an internal craze generated therein, and having a fine cracked pattern. Craze is composed of molecular bundles (fibrils) and microvoids, and has a structure similar to that of sponge as a whole. The microvoids constituting the craze are fine through holes that hardly allow air to pass through under normal conditions, but expand to give air permeability when pressurized.

  By forming the air vent 25 in the center of the seal plate 23 in this way, a lubricant such as grease enclosed in the joint during rotation of the constant velocity joint is unevenly distributed on the outer diameter side inside the joint by centrifugal force. Therefore, the adhesion of grease can be made very small in the vicinity of the vent 25. Therefore, the breathable film 26a can be prevented from being covered with grease, the air in the constant velocity joint can enter and exit through the breathable film 26a without any trouble, and the boot 2 can be prevented from being deformed by pressure. . Furthermore, by shifting the position of the air permeable film 26a from 1 to 20 mm from the center of rotation, even if grease is attached to the air permeable film 26a, the grease is naturally removed from the air permeable film 26a easily by centrifugal force. Will be.

  In order to prevent the leakage of grease from the vent 25 more completely, as shown in FIGS. 1 (B) and 1 (C), the seal plate 23 in the vent 25 is made of a double wall of an inner wall and an outer wall. 23a. That is, a circular or radial gas-liquid separation space 27 that extends thinly in the radial direction is formed inside the double wall 23a, and a first vent 25a is formed at the center of the outer wall. Then, inside the first vent 25a (or outside), an air permeable film 26a that generates craze that allows passage of air but prevents passage of liquid is fixed by any method such as adhesion or caulking. To do. A second vent 25b is formed at the center of the inner wall, and a return port 28 communicating with the gas-liquid separation space 27 is formed at a predetermined position radially outward of the second vent 25b on the inner wall. . A plurality of return ports 28 may be formed in the circumferential direction, or only one may be formed. As shown in FIGS. 1B and 1C, the double wall 23a can be easily obtained by fixing an integrated perforated plate-like member 29 having a smaller diameter than the seal plate 23 to the seal plate 23 by an arbitrary method. Can be configured. Further, as shown in FIG. 1D, the air-permeable film 26a is held in the perforated dish-shaped member 30, and a plurality of claws 30a at the center of the dish-shaped member 30 are formed around the peripheral portion of the air-permeable film 26a. If it is configured to be fixed at, the installation of the air permeable film 26a can be omitted, which is more convenient.

  As described above, if at least the central portion of the seal plate 23 is the double wall 23 a and the return port 28 is formed around the second vent 25 b, the grease is centrifuged even if the grease leaks to the gas-liquid separation space 27. The force is swung off to the peripheral portion of the gas-liquid separation space 27 and returned from the return port 28 into the constant velocity joint.

  In the constant velocity joint of FIG. 1 (B), one gap 31 or a circle extending in the radial direction is provided between the mounting flange portion 24a of the second shaft 24 and the mounting portion of the outer ring 4 that can be mounted thereto. Two or more are formed at equal intervals in the circumferential direction. The gap 31 communicates the internal space of the mounting flange portion 24a with the outside, and ensures the entry and exit of air through the gap 31. Since the gap 31 extends in the radial direction, external dust and muddy water are less likely to enter due to centrifugal force, but have a structure that does not interfere with the entry and exit of air.

  In the first embodiment described above, since the air vent 25 (25a, 25b) and the air permeable film 26a are disposed at or near the rotation center position of the constant velocity joint, the grease in the joint acts on the centrifugal force. Therefore, it is difficult to reach the vent 25 (25a, 25b). Or when it arrange | positions in an eccentric position, even if grease adheres to the air permeable film 26a, it can be naturally removed from the air permeable film 26a easily by centrifugal force. For this reason, the air permeability of the air permeable film 26a is not hindered by the grease, and leakage of the grease can be effectively prevented. Further, the dust and muddy water outside the joint are prevented from entering by the air permeable film 26a.

Next, a second embodiment of the present invention will be described.
As shown in FIG. 2, in the second embodiment, an outer ring portion 24b is formed integrally with the second shaft 24, and the seal plate 23 as shown in FIG. 1 (A) or FIG. 1 (B) is eliminated. Since the outer ring portion 24b is integrally formed with the second shaft 24, a bolt for attaching the outer ring is not necessary. Further, the shape of the reinforcing metal ring 3a of the boot 2 is also different. As shown in FIG. 1A or FIG. 1B, the metal ring 3a is not fitted or bolted to the outer ring 4, but is integrated with the boot 2. The large-diameter mounting portion 2 a of the boot 2 is directly fitted into the outer ring portion 24 b and is fastened and fixed by the boot band 10.

  In this case, a slightly thick partition wall 24c is integrally formed at the left end of the outer ring portion 24b (outer ring). Since the opening of the outer ring portion 24b is closed by the partition wall portion 24c, the airtightness is high as compared with the structure of FIG. 1 (A) or FIG. 1 (B). That is, the partition wall 24c and the boot 2 constitute a seal structure. And the vent hole 32 is formed in the position which deviated 1-20 mm from the shaft center vicinity or the shaft center of the partition part 24c. The size and shape of the vent 32 are not particularly limited as in FIG. 1 (A) or FIG. 1 (B). It is sufficient if there is a size (for example, a circular hole having a diameter of 5 mm or less) necessary for a slight amount of air. An air permeable film 26a formed of craze that allows passage of air but prevents passage of liquid is fixed to the outside of the air vent 32 by any means such as adhesion or caulking. If necessary, the peripheral portion of the breathable film 26a is fixed to the partition wall portion 24c with a fixing perforated plate 36 or the like instead of or in combination with the bonding. Since the partition wall portion 24c is relatively thick and the axial distance of the air vent 32 is long, the grease is less likely to reach the air permeable film 26a. Other structures are the same as those shown in FIGS.

  In the third embodiment of the present invention, as shown in FIGS. 3 (A) and 3 (B), a third vent hole 33 penetrating inward and outward in the axial direction is formed in a part of the small diameter mounting portion 2b of the boot 2, A breathable film 26b formed by generating crazes that allow the passage of air but prevents the passage of liquid is fitted into the inlet portion of the inner surface or the outer surface of the third vent 33. The size of the third vent 33 is not particularly limited. Appropriate through-holes are formed at a single location or at a plurality of locations at equal intervals in the circumferential direction. Other structures are the same as those of the constant velocity joint described with reference to FIG.

  In the fourth embodiment of the present invention, as shown in FIGS. 4A, 4B, and 4C, a fourth vent 37 is provided in the boot oblique side portion 38 adjacent to the small diameter mounting portion 2b of the boot 2, A gas-permeable film 26e formed by forming a craze that allows passage of air but prevents passage of liquid is fitted and fixed to the four vent holes 37 by any means such as adhesion. The size and shape of the fourth vent 37 are not particularly limited as described above. For example, one or a plurality of circular holes having a diameter of about 1 mm are formed. However, it is a common sense number that does not cause abnormal deformation of the boots 2. FIG. 4A shows an example of a boot shape found in a general propeller shaft rubber boot. FIG. 4B is an example of a shape found in a rubber boot for a drive shaft or a propeller shaft, and FIG. 4C is an example of a boot shape found in a resin boot for a drive shaft or a propeller shaft.

  In the third embodiment described above, the third vent 33 and the breathable film 26b are arranged apart from the rotation center position of the constant velocity joint by the radius of the first shaft 1, but the outer periphery of the first shaft 1 As can be seen from FIG. 3, centrifugal force acts radially outward on the grease in the region. For this reason, even if a small amount of grease adheres to the inner side surface of the air permeable film 26b, the centrifugal force and the passage preventing function by the air permeable film 26b combine to reliably prevent leakage of the grease. Further, air permeability and prevention of intrusion such as dust are the same as those in the first embodiment and the second embodiment.

  Further, in the fourth embodiment, the fourth vent 37 and the breathable film 26e are arranged apart from the rotation center of the constant velocity joint, but a small amount of grease is applied by the action of centrifugal force as in the third embodiment. Is naturally removed even if it adheres to the inner surface of the breathable film 26e. Moreover, air permeability and prevention of intrusion such as dust are the same as in the first to third embodiments.

The above breathable film will be described in detail below.
The breathable film is a polymer resin film in which striped crazes substantially parallel to the molecular orientation direction are generated. As a raw material of the polymer resin film, for example, polyvinylidene fluoride, polystyrene, polyethylene, polypropylene, polyester, polyamide or the like can be employed.

  As a method for manufacturing this air-permeable film, as shown in FIG. 5, a polymer resin film 40 is bent substantially in parallel with the molecular orientation direction to form a local fold line 41. Then, the upper and lower surfaces of the bent polymer resin film 40 are pressed by a pair of pressing members 42, 42, and the pressing members 42, 42 are moved in a direction orthogonal to the bending line 41 in opposite directions. The resin film 40 is pulled. By doing so, striped crazes are generated in the polymer resin film 40 substantially parallel to the molecular orientation direction.

  Moreover, another manufacturing method of a breathable film is shown in FIG. As shown in the figure, an acute angle corner 43a of a pressing body 43 (blade) is pressed against one surface of the polymer resin film 40 held in a tension state so as to be approximately parallel to the molecular orientation direction of the polymer resin film 40. A typical fold line 41 is formed. Then, the polymer resin film 40 is pulled in a direction orthogonal to the fold line 41 while the corner portion 43 a of the pressing body 43 is pressed against the polymer resin film 40. Thereby, striped crazes are generated in the polymer resin film 40 substantially in parallel with the molecular orientation direction.

  In addition, by changing the temperature, tension, or bending angle of the polymer resin film when forming the craze, the interval between crazes, the width of the craze, the ratio of the craze that penetrated, can be changed, It is possible to easily adjust the air permeability.

  Further, an additive layer may be formed on the craze. For example, the additive layer can contain a stabilizer to improve the durability of the breathable film, or the additive layer can contain a plasticizer to improve the flexibility of the breathable film. The types of additives are not limited to those mentioned here, and various additives can be applied depending on the purpose of use.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention. For example, the arrangement position of the air permeable film is not limited to the arrangement position of the above-described embodiment, and may be an arbitrary position of the seal structure.

(A) is sectional drawing of the constant velocity joint which concerns on 1st Embodiment of this invention, (B) is sectional drawing of the modification of the constant velocity joint which concerns on 1st Embodiment of this invention, (C) is (B). (D) is an expanded sectional view of the modification of the vent part of (B). It is sectional drawing of the constant velocity joint which concerns on 2nd Embodiment of this invention. (A) is sectional drawing of the boot of the constant velocity joint which concerns on 3rd Embodiment of this invention, (B) is BB sectional view taken on the line of (A). (A) is a partial cross-sectional view of a constant velocity joint boot according to a fourth embodiment of the present invention (an example of a propeller shaft rubber boot), and (B) is a constant velocity joint boot according to a fourth embodiment of the present invention. (C) is a partial cross-sectional view of a constant velocity joint boot according to a fourth embodiment of the present invention (resin boot of a drive shaft or a propeller shaft). Example). It is a front view which shows one Example of the manufacturing method of the air permeable film used for this invention. It is an enlarged front view which shows the other Example of the manufacturing method of the air permeable film used for this invention. It is sectional drawing of the small diameter attaching part of the boot which shows the ventilation structure of the conventional boot. FIG. 8 is a cross-sectional view taken along line VII-VII in FIG. 7. It is an expanded sectional view of the lip | rip part of the boot of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2 Boot 2a Large diameter attachment part 2b Small diameter attachment part 2c Bending part 3 Metal ring 4 Outer ring 5 Boot band 6 Inner ring 7 Ball 8 Cage 9 Bolt 13 Ventilation hole 14 Lip part 15 Protrusion 19 Retainer ring 20 First groove 21 Pocket 22 2nd groove 23 Seal plate 23a Double wall 24 2nd shaft 24a Flange part 24b Outer ring part 24c Partition part 25 Ventilation hole 25a 1st ventilation hole 25b 2nd ventilation hole 26a Breathable film 26b Breathable film 26e Breathable film 27 Gas / Liquid Separation Space 28 Return Port 29 Dish-shaped Member 30 Dish-shaped Member 30a Claw 31 Clearance 32 Ventilation Port 33 Third Vent Port 36 Perforated Plate 37 Fourth Vent Port 38 Boot Oblique Side 40 Polymer Resin Film 41 Bending Wire 42 Holding member 43 Pressing body 43a Corner

Claims (11)

An outer ring, an inner ring disposed so as to be swingable relative to the outer ring, a shaft having one end connected to the inner ring, and the inner and outer rings, allowing the inner ring to swing and engaging the inner and outer rings. A plurality of torque transmitting members that transmit torque between the inner and outer rings and a seal structure that hermetically seals the left and right openings of the outer ring, and at least the seal structure around the shaft is allowed to swing. In the constant velocity joint composed of rubber or resin boots,
A part of the sealing structure is a breathable film that allows air to pass but prevents liquid from passing , and forms a stripe-shaped craze substantially parallel to the molecular arrangement direction on the polymer resin film. configured,
The constant velocity joint according to claim 1, wherein at least one of an interval between crazes of the breathable film, a width of craze, and a ratio of craze penetrated is changed in accordance with a required air flow rate of the constant velocity joint. Claim 1, characterized in that the vent is formed in the central portion of the seal assembly to seal an opening of the outer ring opposite the shaft airtight the vent was closed with the breathable film Constant velocity joint. Characterized in that the shaft and the vent forming an opening of said outer ring opposite to the position 1~20mm eccentric from the rotation center of the seal assembly to seal hermetically, the vent was closed with the breathable film The constant velocity joint according to claim 1. At least a central portion of the seal structure that hermetically seals the opening of the outer ring opposite to the shaft is constituted by a double wall of an outer wall and an inner wall, and air that extends radially inside the double wall. forming a liquid separation space, to form a first vent in the center of the outer wall, said first vent closed by said breathable film to form a second vent in the center of the inner wall The constant velocity joint according to claim 2, wherein a return port communicating with the gas-liquid separation space is formed radially outward of the second vent on the inner wall.   The outer ring has a vehicle mounting surface that can be mounted on a mounting flange portion of a vehicle, and a gap is partially provided between the vehicle mounting surface and the mounting flange portion, and this gap is formed in the vent or the first vent. The constant velocity joint according to any one of claims 1 to 4, wherein the constant velocity joint is communicated with the outside of the joint. Wherein forming the third vent extending axially mounting portion of the boot contacting the outer circumferential surface of the shaft, the third vent according to claim 1, characterized in that closed by the breathable film Constant velocity joint.   The constant velocity joint according to claim 6, wherein the third vent hole is a single or a plurality of fine holes formed along an axial direction in a mounting portion between the boot and the shaft. In the rubber or resin boot, which is the seal structure around the shaft, a single or a plurality of fourth vent holes are formed in the boot oblique side portion adjacent to the boot mounting portion in contact with the outer peripheral surface of the shaft. and, constant velocity joint according to claim 1, characterized in that the fourth vent was closed by the breathable film. The constant velocity joint according to any one of claims 1 to 8, wherein an additive layer is formed on the craze . The polymer resin film is folded substantially in parallel with the molecular orientation direction to form a fold line, and while holding both sides of the folded polymer resin film with a pressing member, the polymer resin film is pulled in a direction orthogonal to the fold line. The constant velocity joint according to any one of claims 1 to 9, wherein the craze having a stripe shape substantially parallel to a molecular orientation direction is generated . On one surface of the polymer resin film, a sharp corner of the pressing body is pressed substantially in parallel with the molecular orientation direction of the polymer resin film to form a fold line, and the corner of the pressing body is applied to the polymer resin film. any pressing as-a polymer resin film parts from claim 1, characterized in that to produce the folding said molecular alignment direction by pulling in a direction perpendicular to the line substantially in parallel with striped the Craze 9 The constant velocity joint according to claim 1 .

Images