JP4527581B2 - Constant velocity universal joint with boots - Google Patents

Description

  The present invention relates to a constant velocity universal joint with a boot used in a power transmission system of an automobile or various industrial machines.

  Constant velocity universal joints are used with boots attached to prevent leakage of grease sealed inside and entry of foreign matter from outside. This boot generally has a large-diameter mounting portion attached to the boot mounting portion provided at the opening end of the outer joint member of the constant velocity universal joint, and a second rotation connected to the inner joint member of the constant velocity universal joint. A small-diameter mounting portion mounted on the shaft and a bent portion that integrally connects both mounting portions. As a boot for a constant velocity universal joint, a boot formed of rubber such as chloroprene or a thermoplastic elastomer is widely used.

  On the other hand, for constant velocity universal joints, a type that can take a large operating angle of about θ = 45 to 50 deg (for example, a fixed type constant velocity universal joint using a ball such as a Zepper type or a barfield type), or an operating angle. However, there is a type having a mechanism that slides in the axial direction of the outer joint member (for example, a double offset type, a tripod type, a cross groove type, etc.).

The shape of the outer joint member of the constant velocity universal joint may be cylindrical or non-cylindrical in the shape of the opening end. From the viewpoint of weight reduction and workability of the constant velocity universal joint, there are many cases where it is more efficient to use a non-cylindrical shape considering the internal structure. Chloroprene rubber boots have been mainly used as constant velocity universal joint boots applied to such non-cylindrical outer joint members. Recently, the application of thermoplastic elastomer boots has also been studied (see Patent Documents 1 to 5).
Japanese Patent Laid-Open No. 10-110738 JP 10-196673 A JP 2002-13546 A JP 2003-194093 A JP 2003-329057 A

  Chloroprene rubber boots have relatively good performance as boots for constant velocity universal joints, but have aspects such as fatigue resistance, wear resistance, low temperature resistance, heat aging resistance, and grease resistance (oil resistance). However, since it may not be sufficient depending on the use conditions, it tends to be replaced with a thermoplastic elastomer boot having better performance.

  However, a chloroprene rubber boot is mainly used for a constant velocity universal joint using an outer joint member having a non-cylindrical shape of the boot mounting portion. This is because it is difficult to mold a large-diameter mounting part into a non-cylindrical shape in which a thin-walled part and a thick-walled part alternate in the circumferential direction, and to a complicated shape including the axial direction. This is because of this. Alternatively, since the thermoplastic elastomer is somewhat poor in elasticity and high in material hardness due to material properties, there are cases where the boot mounting property to the outer joint member is difficult or the sealing performance is insufficient.

  When the thermoplastic elastomer boot is applied to the non-cylindrical outer joint member, the non-cylindrical outer joint member is provided between the non-cylindrical outer joint member and the large-diameter mounting portion of the cylindrical boot, or the non-cylindrical outer joint member. A type in which the large-diameter mounting portion of the boot is formed into a non-cylindrical shape along the outer joint member, and an intermediate member (bushing) is interposed between the non-cylindrical boot large-diameter mounting portion and the band. Can be considered. However, these forms increase the number of parts, which is not preferable in terms of management and process. In addition, the cost increases. Or since a certain amount of thickness is required for a bushing, an outer diameter dimension becomes large. Further, the sealability at the contact portion between the outer joint member / boot and between the boot / bushing is insufficient.

  On the other hand, the large-diameter mounting portion of the boot is formed with a substantially constant thickness along the non-cylindrical outer joint member, and the outer peripheral surface of the boot is tightened with a band shaped along the non-cylindrical shape. However, since the band has a complicated shape, the cost increases and the sealing performance is insufficient.

  In addition, the inner peripheral surface of the large-diameter mounting portion of the boot is shaped along the shape of the non-cylindrical outer joint member, the outer peripheral surface of the large-diameter mounting portion of the boot is cylindrical, and the thickened portion A boot made of a thermoplastic elastomer or the like having been provided is proposed (FIG. 2 of Japanese Patent Laid-Open No. 2003-329057), but this has a problem that the sealing performance is insufficient.

  An object of the present invention is to provide a constant velocity universal joint with a boot having a boot having sufficient durability and sufficient sealing performance.

The invention according to claim 1 includes an outer joint member that is coupled to the first rotating shaft so as to be able to transmit torque, an inner joint member that is coupled to be able to transmit torque to the second rotating shaft, and an outer joint member and an inner joint member. In a constant velocity universal joint with a boot comprising a torque transmission member that transmits torque interposed therebetween, and a boot mounted between the outer joint member and the second rotating shaft,
The cross-sectional shape of the outer joint member is composed of linear portions and concave arc portions that appear alternately in the circumferential direction, and the linear portion is located in the phase of the track groove on which the torque transmitting member rolls, and the concave arc portions are adjacent to each other. Located between the straight sections,
The boot has a large-diameter mounting portion composed of an inner peripheral surface and a cylindrical outer peripheral surface along the outer shape of the boot mounting portion of the outer joint member, the entire volume being satisfied by the boot material,
A protrusion is provided at the boot mounting portion corresponding to the boundary portion between the straight portion and the concave arc portion of the outer joint member, and the large-diameter mounting portion of the boot having the corresponding phase is fitted with the protrusion of the outer joint member. There is a hollow,
The straight portion and the concave arc portion of the outer joint member have a smooth axial cross section, and the inner peripheral surface shape of the boot fitted therein is a shape along the straight portion and the concave arc portion of the outer joint member,
A chamfered portion, a straight portion, and the dent are continuously formed from the end surface side in a phase including the dent in the inner peripheral surface of the large-diameter mounting portion of the boot , as viewed in a longitudinal section, and the straight portion has one or more lines. A protrusion extending in the circumferential direction of at least one protrusion is continuously formed over all of the straight part and the concave arc part and the boundary part between the two,
The recess and the protrusion of the boot are characterized by being positioned within the range of the width of the band groove provided on the outer peripheral surface of the large-diameter mounting portion of the boot.
Here, the straight line portion is not necessarily limited to a literal straight line, but includes a straight line portion. In addition, the concave arc portion means a concave portion having a smaller diameter than the straight portion, and therefore the cross-sectional shape of the outer shape of this portion may be linear.

According to a second aspect of the present invention, there is provided an outer joint member that is coupled to the first rotating shaft so as to be able to transmit torque, an inner joint member that is coupled to be able to transmit torque to the second rotating shaft, and an outer joint member and an inner joint member. In a constant velocity universal joint with a boot comprising a torque transmission member that transmits torque interposed therebetween, and a boot mounted between the outer joint member and the second rotating shaft,
An outer shape of the outer joint member is composed of first and second convex arc portions alternately appearing in the circumferential direction, and the first convex arc portion is positioned outside the phase of the track groove on which the torque transmitting member rolls. The second convex arc portion has a center different from the axis of the joint member, and the first convex arc portion concentrically adjacent to the axis of the outer joint member is connected,
The boot has a large-diameter mounting portion composed of an inner peripheral surface along the outer shape of the boot mounting portion of the outer joint member and a cylindrical outer peripheral surface, the entire volume being filled with the boot material,
A protrusion is provided in the boot mounting portion of the first convex arc portion of the outer joint member, and a recess for fitting with the protrusion is provided in the large-diameter mounting portion of the boot having the corresponding phase. ,
The boot mounting portion of the second convex arc part has a smooth axial cross section, and the inner peripheral surface of the boot fitted therein has a shape along the second convex arc part,
A chamfered portion, a straight portion, and the dent are continuously formed from the end surface side in a phase including the dent in the inner peripheral surface of the large-diameter mounting portion of the boot , as viewed in a longitudinal section, and the straight portion has one or more lines. A protrusion extending in the circumferential direction is provided, and at least one protrusion is continuously formed over the entire circumference of the inner peripheral surface of the large-diameter mounting portion,
The recess and the protrusion of the boot are characterized by being positioned within the range of the width of the band groove provided on the outer peripheral surface of the large-diameter mounting portion of the boot.

  According to a third aspect of the present invention, in the constant velocity universal joint with a boot according to the first or second aspect, the shoulder rest provided on the inner peripheral surface of the large-diameter mounting portion of the boot contacts the end surface of the outer joint member. Is.

The invention according to claim 4, in any of the boot with the constant velocity universal joint of claims 1 to 3, the cross-sectional shape of the protrusion is a triangle vertex facing axis side of the boot, the projection outer The axial cross section formed in the boot mounting portion of the joint member is in close contact with the smooth boot groove.

According to a fifth aspect of the present invention, in the constant velocity universal joint with a boot according to any one of the first to fourth aspects, the projecting portion forms a slope gradually increasing in diameter from the end surface of the outer joint member, and the maximum diameter of the chamfered portion is It is larger than the minimum diameter of the slope .

A sixth aspect of the present invention is the constant velocity universal joint with a boot according to any one of the first to fifth aspects, wherein the chamfer has an angle with respect to an axis of 20 degrees or more over an axial direction of 1 mm or more from an end face of the large-diameter mounting portion of the boot. it is characterized in that it is 60 ° or less.

  According to a seventh aspect of the present invention, in the constant velocity universal joint with a boot according to any one of the first to sixth aspects, the projecting portion constituting the end surface side wall of the band groove provided in the large-diameter mounting portion of the boot has 3 on the circumference. The projection height is 0.6 mm to 1.2 mm, the axial projection width is 0.6 mm to 2.0 mm, and the circumferential projection width is 10 ° to 25 mm. It is characterized by being less than °.

  The invention according to claim 8 is the constant velocity universal joint with a boot according to any one of claims 1 to 7, wherein the boot is made of a thermoplastic polyester elastomer having a type D durometer hardness of 35 to 50 in accordance with JIS K 6253. It is characterized by.

  According to the present invention, the mounting and positioning stability of the boot with respect to the outer joint member, and the mounting of the band into the boot groove are facilitated, and the workability during assembly is improved. The effect of the present invention is also obtained when the boot material is a rubber material having a type A durometer hardness of 50 or more and 70 or less according to JIS K 6253, such as chloroprene, but as in the invention of claim 8, JIS K 6253. This is more remarkable when the material hardness is relatively high, such as a thermoplastic polyester elastomer having a type D durometer hardness of 35 to 50. For example, a boot made of a thermoplastic polyester elastomer has improved durability as compared with a boot made of chloroprene rubber and can secure sufficient sealing performance, so that the reliability of boot performance is improved. Furthermore, the number of parts can be kept to a minimum and the cost can be reduced.

  For convenience of explanation, prior to the description of the embodiment of the present invention, the basic configuration of a tripod type constant velocity universal joint with a boot developed at the same time will be described first.

  As shown in FIGS. 1 and 2, the tripod type constant velocity universal joint 1 includes an outer joint member 2, a tripod member 4 as an inner joint member, and a roller 6 as a torque transmission member as main components. Further, a boot 10 is provided.

  As shown in the drawing, the outer joint member 2 includes a mouth portion 22 and a stem portion 26 that are integrally formed. The stem portion 26 is coupled to a first rotating shaft (not shown) by a spline or serration shaft 28 formed at an end portion so as to transmit torque. The mouse portion 22 has a cup shape opened at one end, and a track groove 24 extending in the axial direction is formed at a position of the inner circumference in three equal parts. The outer peripheral surface of the mouse portion 22 has a non-cylindrical shape in which the large-diameter portions 22a and the small-diameter portions 22b appear alternately when viewed in cross section (FIG. 2). In this embodiment, the large-diameter portion 22a is a convex arcuate portion coaxial with the outer joint member 2 positioned in the same phase as the track groove 24, and the small-diameter portion 22b is a recess positioned between the adjacent large-diameter portions 22a. It is an arc-shaped part.

  The tripod member 4 includes a boss 42 and a leg shaft 46. The boss 42 is formed with a spline or serration hole 44 that is coupled to the second rotary shaft 3 so that torque can be transmitted. The leg shaft 46 projects in the radial direction from the circumferentially divided position of the boss 42. Each leg shaft 46 of the tripod member 4 carries a roller 6. A plurality of needle rollers 8 are interposed between the leg shaft 46 and the roller 6, and the roller 6 is rotatable about the axis of the leg shaft 46. In FIG. 1, a retaining ring and a washer for preventing the roller 6 from falling off are omitted. Here, a single roller type in which one roller 6 is supported on one leg shaft 46 is illustrated, but a double roller type in which relatively rotatable inner and outer rollers are supported may also be used.

  FIG. 3 shows a longitudinal section of the large diameter portion 22a of the mouse portion 22. As shown in FIG. As shown in the drawing, a boot groove 30 extending in the circumferential direction is formed in the vicinity of the end face 38. The vicinity of the boot groove 30 is referred to as a boot mounting portion of the outer joint member. The bottom surface of the boot groove 30 has a partial cylindrical shape, and is a straight line parallel to the axis in the longitudinal section. A protruding portion 32 is formed over part or all of the circumferential direction of the large diameter portion 22a. The protrusion 32 is preferably located near the end surface 38 of the outer joint member 2.

  In the case of the illustrated example, both sides in the axial direction of the protrusion 32 are inclined surfaces 34 and 36. The inclination angles of the inclined surfaces 34 and 36 with respect to the axis are 25 ° or more and 60 ° or less, preferably 25 ° or more and 45 ° or less. Thereby, the turning efficiency of the outer joint member 2 is improved, and at the same time, the mounting property when the large-diameter mounting portion 12 of the boot 10 is fitted to the outer joint member 2 is improved, and the outer joint member 2 after the boot is mounted. It is also possible to improve the action of preventing the boot 10 from coming off and the position stability.

  If the angle of the first inclined surface, that is, the inclined surface 34 opposite to the end surface 38 of the outer joint member 2 is larger than 60 °, the workability of the boot mounting portion of the outer joint member 2 is deteriorated. On the other hand, when the angle is less than 25 °, the action of preventing the boot 10 from coming off in the axial direction after being fitted to the outer joint member 2 and the position stability are lowered. Moreover, since it becomes a protrusion long in an axial direction, the full width of the boot attachment part of the outer joint member 2 will become large, and it is unpreferable on space efficiency or intensity | strength. When the angle of the second inclined surface, that is, the inclined surface 36 on the end surface 38 side of the outer joint member 2 is larger than 60 °, the boot mounting property is hindered. On the other hand, when the angle is less than 25 °, the protrusion 32 is elongated in the axial direction, so that the entire width of the boot mounting portion is increased, which is not preferable in terms of space efficiency and strength.

  As shown in FIG. 4, the overall appearance of the boot 10 has a truncated cone shape, and includes a large-diameter attachment portion 12, a small-diameter attachment portion 14, and a bent portion 16 therebetween. In the illustrated embodiment, a bellows portion is shown as the bent portion 16, but the present invention can also be applied to boots other than the bellows type. As shown in FIG. 1, the large-diameter mounting portion 12 is fitted to the outer joint member 2, and the small-diameter mounting portion 14 is fitted to the second rotating shaft 3, and is fastened and fixed by boot bands 13 and 15, respectively. It is supposed to be. For this reason, the band groove | channel 18 for receiving the boot bands 13 and 15 is formed in the outer periphery of each attaching part. The bottom surface of the band groove 18 has a cylindrical surface shape, and the longitudinal section is parallel to the axis.

  The boot 10 is made of a thermoplastic elastomer, and every part is filled with the thermoplastic elastomer, and there are no voids. In other words, particularly in the large-diameter mounting portion 12, the entire volume is filled with the boot material. If a gap exists in the large-diameter mounting portion 12, the tightening force of the band 13 (see FIG. 1) is not sufficiently transmitted to the boot mounting portion of the outer joint member 2, and the sealing performance is impaired. Examples of materials that can be employed include thermoplastic polyester elastomers having a type D durometer hardness of 35 to 50 in accordance with JIS K 6253.

  In addition to the mountability of the boot 10 to the outer joint member 2, the mountability of the bands 13, 15 to the boot 10 is an important factor to be considered in assembling the constant velocity universal joint. For example, both side walls of the band groove 18 may be continuously provided on the entire circumference, but in that case, the band mounting property may be lowered. Therefore, among the side walls of the band groove 18, in particular, the protrusion 19 that forms the side wall on the end face side that appears on the right side in FIG. 4 has no problem in the mountability of the band 13 and the position of the band 13 is stable. As the setting to be performed, the following configuration is preferable. That is, as can be seen from FIG. 5, the protrusions 19 are intermittently arranged in the circumferential direction, for example, at three equal positions, and the height of each protrusion 19 is 0.6 mm or more and 1.2 mm or less, and the axial dimension. Is 0.6 mm to 2.0 mm and the circumferential dimension is in the range of 10 ° to 25 ° from the boot axis.

  As shown in FIG. 5, the inner peripheral surface of the large-diameter mounting portion 12 of the boot 10 has a shape along the outer peripheral surface shape of the mouth portion 22 of the outer joint member 2. That is, the thin part 12a corresponding to the large diameter part 22a of the mouse part 22 and the thick part 12b corresponding to the small diameter part 22b appear alternately in the circumferential direction.

  As shown in FIG. 6, the inner peripheral surface of the thin portion 12a of the large-diameter mounting portion 12 includes a chamfered portion A from the end surface side, a straight portion B parallel to the axis, a recess C, and a shoulder pad D as shown in FIG. It is formed continuously.

The chamfered portion A is provided at least 1 mm from the end surface at an angle of 20 ° to 60 ° with respect to the axis. By providing such a chamfered portion A, the above-described boot mounting property can be further improved. The end surface side diameter D ₂ of the chamfered portion A is set to be larger than the minimum diameter D ₁ of the end surface side inclined surface 36 of the protruding portion 32 of the outer joint member 2. The meeting part of the end surface side slope 36 and the end surface 38 of the protrusion 32 of the outer joint member 2 is rounded and smoothly connected. Thus, when the boot 10 is mounted, the chamfered portion A of the boot 10 is guided by the rounded portion, so that the boot 10 can be mounted more smoothly.

The recess C has slopes C ₁ and C ₂ that contact the slopes 34 and 36 of the protrusion 32 in order to receive the protrusion 32 of the outer joint member 2. Assuming that these are the third slope C ₁ and the fourth slope C ₂ , the third slope C ₁ corresponds to the first slope 34 of the protrusion 32, and the fourth slope C ₂ is the first slope of the protrusion 32. Corresponds to the second slope 36. Since it is such a structure, the hollow C fits with the protrusion part 32 of the outer joint member 2, and generates the removal | prevention action to an axial direction.

  The large-diameter attachment portion 12 of the boot 10 is required to be easily attached to the boot attachment portion of the outer joint member 2 and exhibit a sufficient sealing property when tightened with the band 13. Therefore, the recess C provided on the inner surface of the large-diameter mounting portion 12 of the boot 10 has a shape along the protruding portion 32 of the outer joint member 2.

  The contour of the portion of the boot 10 from the recess C to the shoulder pad D substantially matches the contour of the portion of the outer joint member 2 from the protruding portion 32 to the end surface 38. The shoulder rest D abuts against the end face 38 of the outer joint member 2 and serves to stabilize the axial position of the boot 10.

  As shown in FIG. 7, the inner peripheral surface of the thick-walled portion 12b of the large-diameter mounting portion 12 of the boot 10 is continuously formed with a chamfered portion A and a linear portion F parallel to the axis from the end surface side. . The chamfered portion A is the same as that of the thin portion already described.

  Protrusions E that are continuous over the entire circumference are formed on the inner circumferential surface of the large-diameter mounting portion 12 of the boot 10. This protrusion E is located in the said linear part B and F in a thin part and a thick part. The cross-sectional shape of the protrusion E may be a semicircle or a semi-ellipse, but a triangle is more preferable. In the illustrated embodiment, the protrusion E has a triangular cross section, and the apex is directed radially inward of the boot, that is, toward the axial center. The protrusion E contacts the boot groove 30 of the outer joint member 2 and exhibits a sealing function. Two or more protrusions E may be provided. Alternatively, a discontinuous protrusion different from the protrusion E may be provided. By tightening with the band 13, the protrusion E uniformly adheres to the boot groove 30 of the non-cylindrical boot mounting portion of the outer joint member 2 on the circumference and exhibits a sufficient sealing property. The bottom surface of the boot groove 30 of the outer joint member 2 with which the protrusion E is in close contact is smooth. The bottom surface of the boot groove 30 may have various shapes such as providing a protrusion, but is preferably smooth from the viewpoint of the processing man-hour of the outer joint member 2.

  The protrusion E in the large-diameter mounting portion 12 of the boot 10 is smoothly connected by rounding in a concave arc shape at the boundary between the thin portion 12a and the thick portion 12b. As a result, as shown in FIG. 8, the boot is connected to the outer joint member more than the other part of the usual tightening margin at the joint portion of the two different curved surfaces of the circumferential end portion of the boot groove 30 of the outer joint member 2. It becomes possible to bite in and the sealing performance is improved. However, if the radius of curvature is too large, the central portion is “bearing” and a gap is generated, resulting in a decrease in sealing performance. Therefore, the radius of curvature of the roundness is preferably 0.5 mm or more and 5 mm or less.

  The area of the recess C and the protrusion E and the tightening margin of the outer joint member 2 with respect to the boot mounting portion is such that the protrusion E part overcomes the protrusion 32 of the outer joint member 2 due to elastic deformation, and the protrusion E and the outer joint member 2 The setting which can maintain sufficient sealing performance between the boot grooves 30 is required.

  When the material of the boot is high, such as when the material of the boot is a thermoplastic elastomer, especially a thermoplastic polyester elastomer with a type D durometer hardness of 35 or more and 50 or less according to JIS K 6253, this tightening setting is important. is there. The step between the boot groove 30 and the protrusion 32 in the boot attachment portion of the outer joint member 2 is 0.8 mm or more and 1.5 mm, and the large diameter attachment portion 12 of the boot 10 to be attached thereto has a step C with respect to the protrusion 32 of the depression C. It is preferable that the interference is 0.1 mm or more and 1.0 mm or less in radius, and the interference with respect to the boot groove 30 at the tip of the protrusion E is 0.1 mm or more and 1.5 mm or less in radius. Furthermore, the height of the protrusion E is preferably 0.3 mm or greater and 1.0 mm or less.

  With the tightening setting as described above, the large-diameter mounting portion 12 of the boot 10 can be attached to the protrusion E beyond the protruding portion 32 of the outer joint member 2, and then tightened with the band 13, The large-diameter attachment portion 12 of the boot 10 can be attached in close contact with the boot attachment portion of the outer joint member 2. If it is set to be smaller than the above-mentioned tightening margin, there is a possibility that a gap is locally generated by the deformation of the boot 10 when the band 13 is tightened. On the other hand, if the setting is larger than the above-described tightening margin, it is difficult to attach the boot. Moreover, when the height of the protrusion E is less than 0.3 mm, the adhesion of the outer joint member 2 to the groove 30 is lowered, and sufficient sealing performance cannot be obtained. When the height of the protrusion E exceeds 1.0 mm, the volume of the protrusion becomes too large, which is not efficient in terms of design and sealing properties.

  The recess C and the protrusion E of the boot 10 are preferably positioned within the range of the width of the band groove 18. With such a configuration, the band tightening force is transmitted to the protrusion E in the vertical direction, and the restraint in the axial direction of the recess C fitted to the protrusion 32 is strengthened. Sex is obtained.

  Next, a first embodiment shown in FIGS. 9 and 10 and a second embodiment shown in FIGS. 11 and 12 will be described. The first embodiment corresponds to a modification of the basic configuration described above, and the outer joint member 102 of the tripod type constant velocity universal joint has a non-cylindrical shape as shown in FIG. The diameter attaching portion 112 has a shape as shown in FIG. The second embodiment shows a typical example when applied to a double offset type constant velocity universal joint. The outer joint member 202 has a non-cylindrical shape as shown in FIG. 212 has a shape as shown in FIG. These are only examples, and are not limited to the shapes shown in FIGS. 9 to 12, and the outer joint member does not have or hardly has a cylindrical portion concentric with the shaft center at the outermost diameter portion. Any other non-cylindrical shape may be used.

  9 and 10, substantially the same components or parts as those in FIGS. 1 to 7 are represented by the same reference numerals plus 100. Similarly, in FIGS. 11 and 12, substantially the same parts or portions as those in FIGS. 1 to 7 are represented by the same reference numerals plus 200.

  In short, as illustrated in FIGS. 9 and 11, the first and second embodiments are non-cylindrical outer joints that do not have or hardly have a cylindrical shape concentric with the shaft center at the outermost diameter portion. It is characterized by a combination of a constant velocity universal joint using a member and a boot attached to the universal joint.

  The outer joint member 2 described above shown in FIGS. 1 and 2 has a cylindrical shape in which the outermost diameter portion is concentric with the shaft center, and the cylindrical portion (large diameter portion 22a) and the concave arc shape portion (small diameter portion). 22b) appear alternately in the circumferential direction. The outer joint member 102 in FIG. 9 has a different profile from the outer joint member 2 in FIG. 2, and the outer joint member 2 in FIG. 2 has a cylindrical portion (large diameter portion 22 a) concentric with the axis at the phase of the track groove 24. ) Is the outermost diameter portion, but the phase portion in the outer joint member 102 of FIG. 9 is flat or substantially planar as indicated by reference numeral 122a and is not the outermost diameter portion. The outermost diameter portion appears in the phase of the X-O cross section, and the shape thereof is not a cylindrical shape concentric with the axis of the outer joint member 102. It should be noted that a boot mounting portion including the band groove 130 and the protruding portion 132 is provided in the vicinity of the end surface 138 of the outer joint member 102 at the phase of the X-O cross section (FIG. 9B). On the other hand, as indicated by reference numeral 122b in FIG. 9, a portion corresponding to the concave arc-shaped portion (small diameter portion 22b) of the smooth axial cross section in the outer joint member 2 in FIG. 2 is also provided in the outer joint member 102 in FIG. It is.

  FIG. 11 shows an example of the outer joint member 202 of the double offset type constant velocity universal joint. The outermost diameter portion is a phase portion of a track groove on which a ball as a torque transmission member rolls. That is, the cylindrical portion 222a having a center different from the axis of the outer joint member 202 protrudes radially outward, and the adjacent cylindrical portions 222a are connected by the cylindrical portion 222b concentric with the axis of the outer joint member 202. . In the vicinity of the end surface 238 of the outer joint member 202, the point that the boot attaching portion including the boot groove 230 and the protruding portion 232 is provided in the cylindrical portion 222a is the same as in the other embodiments described above. FIG. 11 illustrates the case of a 6-track double offset type constant velocity universal joint, but 7 or 8 tracks are possible, and the number of tracks is not limited.

  As already described with reference to FIG. 8, the joint between the plane portion 122 a and the XO cross section in FIG. 9, the joint between the XO cross section and the concave arc-shaped portion 122 b, and the outer joint member 202 of FIG. 11. Even in the joint portion between the cylindrical portion 222a having a center different from the axial center and the cylindrical portion 222b concentric with the axial center of the outer joint member 202, the circumferential protrusion E in the large-diameter mounting portions 112 and 212 of the boots 110 and 210 is formed. By connecting smoothly with the circular arc shape, the boots 110 and 210 can bite into the outer joint members 102 and 202 more than the other parts at the joints of the two curved surfaces having different contact portions in the boot mounting portions of the outer joint members 102 and 202. It becomes possible to improve the sealing performance.

  Also in the first and second embodiments, as already described in relation to the depression C in the basic configuration described above, the X-- of the inner peripheral surface of the large-diameter mounting portions 112 and 212 of the boots 110 and 210 is used. By providing the depressions 113 and 213 along the shape of the protrusions 132 and 232 of the outer joint members 102 and 202 at the phase of fitting with the O cross section or the cylindrical portion 222a, the action of preventing the axial disconnection is generated. Can do.

  The flat portions 122a and the concave arc-shaped portion 122b having a smooth axial section in FIG. 9 and the boots 110 and 210 corresponding to the cylindrical portion 222b concentric with the axial center of the outer joint member 202 and having a smooth axial section in FIG. The large-diameter mounting portions 112 and 212 have shapes along the smooth axial cross section of the boot mounting portions of the outer joint members 102 and 202, respectively, and the inner peripheral surfaces thereof have X- Continuously formed circumferential projections are formed which are connected from a cylindrical portion 222a having a center different from the O cross section or the axis of the outer joint member 202 in FIG.

  9 corresponds to the concave arcuate portion 122b having a smooth axial section and the flat portion 122a in FIG. 9 and the cylindrical portion 222b having a smooth axial section and concentric with the axial center of the outer joint member 202 in FIG. , 210 may be provided with other protrusions on the inner peripheral surfaces of the large-diameter mounting portions 112 and 212 as needed in addition to the protrusions continuous in the circumferential direction. The outer joint members 102 and 202 are also applied to the concave arcuate portion 122b having a smooth axial section and the flat portion 122a in FIG. 9 and the cylindrical section 222b concentric with the axial center of the outer joint member 202 and having a smooth axial section in FIG. Although the above-described shape in which the boot grooves 130 and 230 and the protrusions 132 and 232 are provided in the boot mounting portion of FIG. 9 may be applied, the flat portion 122a of the outer joint member 102 in FIG. It is not preferable in terms of processing efficiency to process the boot groove or the protruding portion in the portion 122b or the cylindrical portion 222b that is concentric with the axial center of the outer joint member 202 in FIG.

It is a longitudinal cross-sectional view of a tripod type constant velocity universal joint. It is a cross-sectional view of the tripod type constant velocity universal joint of FIG. It is a principal part enlarged view of the outer joint member in FIG. It is a longitudinal cross-sectional view of boots. It is a right view of the boot of FIG. It is an enlarged view of the thin part of the boot of FIG. It is an enlarged view of the thick part of the boot of FIG. It is detail drawing of the contact part of an outer joint member and a boot, Comprising: (A) shows both separately and (B) shows the state which fitted the boot to the outer joint member. (A) is an end view of the outer joint member of the tripod type constant velocity universal joint showing the first embodiment, and (B) is an X-O-Y sectional view of FIG. 9 (A). (A) is an end view of the boot in the first embodiment, and (B) is a longitudinal sectional view. (A) is an end view of the outer joint member of the double offset type constant velocity universal joint showing the second embodiment, and (B) is a longitudinal sectional view. (A) is an end view of the boot in the second embodiment, and (B) is a longitudinal sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tripod type constant velocity universal joint 2 Outer joint member 22 Mouse | mouth part 22a Large diameter part 22b Small diameter part 24 Track groove 30 Boot groove 32 Projection part 38 End surface 26 Stem part 28 Spline or serration shaft 4 Tripod member 42 Boss
44 Spline or serration hole 46 Leg shaft 6 Roller 8 Needle roller 10 Boot 12 Large diameter mounting portion 12a Thin wall portion 12b Thick wall portion 14 Small diameter mounting portion 16 Bellows portion (bending portion)
18 Band groove 19 Projection

Claims (8)

An outer joint member that is coupled to the first rotary shaft so as to be able to transmit torque, an inner joint member that is coupled to the second rotary shaft so as to be able to transmit torque, and an intermediate joint member interposed between the outer joint member and the inner joint member. In a constant velocity universal joint with a boot comprising a torque transmission member for transmitting, and a boot mounted between the outer joint member and the second rotating shaft,
The cross-sectional shape of the outer joint member is composed of linear portions and concave arc portions that appear alternately in the circumferential direction, and the linear portion is located in the phase of the track groove on which the torque transmitting member rolls, and the concave arc portions are adjacent to each other. Located between the straight sections,
The boot has a large-diameter mounting portion composed of an inner peripheral surface and a cylindrical outer peripheral surface along the outer shape of the boot mounting portion of the outer joint member, the entire volume being satisfied by the boot material,
A protrusion is provided at the boot mounting portion corresponding to the boundary portion between the straight portion and the concave arc portion of the outer joint member, and the large-diameter mounting portion of the boot having the corresponding phase is fitted with the protrusion of the outer joint member. There is a hollow,
The straight portion and the concave arc portion of the outer joint member have a smooth axial cross section, and the inner peripheral surface shape of the boot fitted therein is a shape along the straight portion and the concave arc portion of the outer joint member,
A chamfered portion, a straight portion, and the dent are continuously formed from the end surface side in a phase including the dent in the inner peripheral surface of the large-diameter mounting portion of the boot , as viewed in a longitudinal section, and the straight portion has one or more lines. A protrusion extending in the circumferential direction of at least one protrusion is continuously formed over all of the straight part and the concave arc part and the boundary part between the two,
The constant velocity universal joint with a boot, wherein the recess and the protrusion of the boot are located within a width range of a band groove provided on an outer peripheral surface of a large-diameter mounting portion of the boot. " An outer joint member that is coupled to the first rotary shaft so as to be able to transmit torque, an inner joint member that is coupled to the second rotary shaft so as to be able to transmit torque, and an intermediate joint member interposed between the outer joint member and the inner joint member. In a constant velocity universal joint with a boot comprising a torque transmission member for transmitting, and a boot mounted between the outer joint member and the second rotating shaft,
An outer shape of the outer joint member is composed of first and second convex arc portions alternately appearing in the circumferential direction, and the first convex arc portion is positioned outside the phase of the track groove on which the torque transmitting member rolls. The second convex arc portion has a center different from the axis of the joint member, and the first convex arc portion concentrically adjacent to the axis of the outer joint member is connected,
The boot has a large-diameter mounting portion composed of an inner peripheral surface along the outer shape of the boot mounting portion of the outer joint member and a cylindrical outer peripheral surface, the entire volume being filled with the boot material,
A protrusion is provided in the boot mounting portion of the first convex arc portion of the outer joint member, and a recess for fitting with the protrusion is provided in the large-diameter mounting portion of the boot having the corresponding phase. ,
The boot mounting portion of the second convex arc part has a smooth axial cross section, and the inner peripheral surface of the boot fitted therein has a shape along the second convex arc part,
A chamfered portion, a straight portion, and the dent are continuously formed from the end surface side in a phase including the dent in the inner peripheral surface of the large-diameter mounting portion of the boot , as viewed in a longitudinal section, and the straight portion has one or more lines. A protrusion extending in the circumferential direction is provided, and at least one protrusion is continuously formed over the entire circumference of the inner peripheral surface of the large-diameter mounting portion,
The constant velocity universal joint with a boot, wherein the recess and the protrusion of the boot are located within a width range of a band groove provided on an outer peripheral surface of a large-diameter mounting portion of the boot.   The constant velocity universal joint with a boot according to claim 1 or 2, wherein a shoulder rest provided on an inner peripheral surface of the large-diameter mounting portion of the boot is in contact with an end face of the outer joint member. Cross-sectional shape of the projection, the vertex is a triangle facing axis side of the boot, and wherein the projection is an axial cross-section formed in the boot mounting section of the outer joint member is in close contact with the smooth boot groove The constant velocity universal joint with a boot in any one of Claim 1 thru | or 3. 5. With the boot according to claim 1, wherein the protruding portion forms a slope gradually expanding from the end face of the outer joint member, and the maximum diameter of the chamfered portion is larger than the minimum diameter of the slope. Fast universal joint. The chamfer, according to claim 1 to a constant velocity universal with one of 5 boots, characterized in that the angle relative to the axis in the axial direction for more than 1mm from the end surface of the large diameter mounting portion of the boot is less than 60 ° 20 ° Fittings.   The protrusions constituting the end face side wall of the band groove provided in the large-diameter mounting portion of the boot are equally distributed to an odd number of three or more places on the circumference, and the protrusion height is 0.6 mm or more and 1.2 mm or less. The axial quotient projection width is 0.6 mm or more and 2.0 mm or less, and the circumferential projection width is 10 ° or more and 25 ° or less. Fittings.   The constant velocity universal joint with a boot according to any one of claims 1 to 7, wherein the boot is made of a thermoplastic polyester elastomer having a Type D durometer hardness of 35 to 50 according to JIS K 6253.

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