JP2008019958A - Tripod type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily cope with demands for wide operation angle by expanding axial displacement quantity of a joint inside component to an opening side of an outer ring. <P>SOLUTION: This joint is provide with the outer ring 10 having a bottomed cylindrical shape of which one end opens and provided with three track grooves 12 extending in an axial direction on an inner circumference and provided with opposing roller guide surfaces 14 provided on an inner side wall of each track groove 12, a tripod member 20 provided in the outer ring 10 and including three leg shafts 24 of which tip is inserted in the track groove 12, and a roller 30 rotatably supported by the leg shaft 24 and rollably inserted in the track groove 12 of the outer ring 10 and guided along the roller guide surface 14. At least an opening end part 11 of the roller guide surface 14 of the outer ring 10 is formed in an arc shape expanding toward the opening side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is used in power transmission systems of automobiles and various industrial machines, and is incorporated in, for example, a drive shaft or a propeller shaft used in a 4WD vehicle, an FR vehicle, or the like, and axially between two axes of a driving side and a driven side. The present invention relates to a tripod type constant velocity universal joint which is one of sliding type constant velocity universal joints that allow displacement and angular displacement.

  For example, a tripod type constant velocity universal joint is one of constant velocity universal joints used as a means for transmitting rotational force from an automobile engine to wheels at a constant speed. This tripod type constant velocity universal joint connects two shafts on the drive side and the driven side, transmits rotational torque at a constant speed even if the two shafts take an operating angle, and also allows relative displacement in the axial direction. It has a structure that can

  6 and 7 show a basic structure of a general tripod type constant velocity universal joint. FIG. 6 shows a transverse section with respect to the joint axis, and FIG. 7 shows a longitudinal section with respect to the joint axis.

  The tripod type constant velocity universal joint shown in the figure is composed of an outer ring 110 as an outer joint member, a tripod member 120 as an inner joint member, and a roller 130 as a rolling element. One shaft (not shown) of the drive side and the driven side to be coupled is coupled to the outer ring 110, and the other shaft 150 is coupled to the tripod member 120.

The outer ring 110 has a bottomed cylindrical shape with one end opened, and three track grooves 112 extending in the axial direction are formed on the inner circumference thereof at equal intervals in the circumferential direction. The tripod member 120 has three leg shafts 124 projecting radially outward from the cylindrical boss portion 122, and these leg shafts 124 are inserted into the track grooves 112 of the outer ring 110 and engaged with the track grooves 112. Torque transmission. A roller 130 is rotatably fitted on the leg shaft 124 via a needle roller 140, and the roller 130 rolls along a pair of roller guide surfaces 114 facing each other in the track groove 112, thereby connecting two shafts. Smooth the angular displacement and axial displacement between.
Japanese Patent No. 3612962

  By the way, in the conventional tripod type constant velocity universal joint, as described above, the joint internal parts including the tripod member 120 and the roller 130 have a structure that can be displaced in the axial direction. An axial displacement region (hereinafter referred to as a slide range) of the joint internal component is such that the roller 130 that rolls along the roller guide surface 114 of the outer ring 110 comes from the innermost position where the roller 130 contacts the bottom of the outer ring 110. The point of contact with the roller guide surface 114 reaches the outermost position on the roller guide surface 114 at the opening end of the outer ring 110.

  FIG. 8A is a simplified view of the track groove 112 formed on the inner circumference of the outer ring 110 as seen from the joint axis. The outermost position of the roller 130 is the contact point X of the roller 130 at the opening end of the track groove 112. Is the position on the roller guide surface 114, that is, the position where the center O of the roller 130 coincides with the opening end surface 116 of the outer ring 110 in the axial direction (the position of the roller 130 indicated by a solid line).

  FIG. 8B is a slide diagram showing the relationship of the operating angle with respect to the axial displacement. In the region surrounded by the illustrated trapezoid, the axial displacement and the operating angle can take predetermined values.

  In the drawing, the outermost position of the roller 130 is a position that coincides with the opening end surface 116 of the outer ring 110, but in practice, the falling of the roller 130 from the outer ring 110 is considered, or the opening end of the outer ring 110 is considered. Since a retaining ring is fitted on the inner circumference as a retaining structure for the joint internal parts, the outermost position of the roller 130 is a position that enters several mm from the opening end surface 116 of the outer ring 110.

  In recent years, this kind of tripod type constant velocity universal joint has also been required to have a high operating angle, but the axial displacement in the high operating angle region (hereinafter referred to as “sliding amount”) has been reduced, resulting in a high operating angle. Even with a constant velocity universal joint that achieves an operating angle, there is a problem that it is difficult to put the constant velocity universal joint into practical use if the sliding amount is small.

  In order to secure the sliding amount in the high operating angle region, the sliding amount is determined by the interference between the shaft 150 connected to the tripod member 120 by spline fitting and the outer ring 110, so that the shaft diameter is not changed. Although it is conceivable to increase the outer diameter of the outer ring 110, in that case, the increase in the size of the outer ring 110 increases the weight and increases the cost, which is not a preferable means.

  In order to increase the sliding amount of the constant velocity universal joint, a structure in which a two-step chamfered portion is provided at the inner diameter portion between the track grooves of the outer ring has been proposed (for example, see Patent Document 1). In this constant velocity universal joint, by providing a two-step chamfered portion at the inner diameter part between the track grooves of the outer ring, the sliding range of the inner part of the joint is expanded to the opposite side of the outer ring, that is, the back side. .

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to easily meet the demand for higher operating angle by expanding the sliding range of the joint internal parts to the opening side of the outer ring. Is to provide a tripod type constant velocity universal joint.

  As technical means for achieving the above-mentioned object, the present invention has a bottomed cylindrical shape with one end opened, and has three track grooves extending in the axial direction on the inner periphery, and on the inner wall of each track groove. An outer joint member provided with roller guide surfaces facing each other, a tripod member having three leg shafts disposed inside the outer joint member and having a tip inserted into the track groove, and freely rotatable on the leg shaft And a tripod type constant velocity universal joint provided with a roller that is rotatably inserted into a track groove of the outer joint member and guided along the roller guide surface, at least of the roller guide surface of the outer joint member The opening end portion has an arc shape whose diameter increases toward the opening side.

  In the tripod type constant velocity universal joint according to the present invention, at least the opening end of the roller guide surface of the outer joint member is formed in an arc shape whose diameter increases toward the opening side, so that the roller is open on the opening side of the outer joint member. , The contact point between the roller and the roller guide surface exists at the arc-shaped open end of the roller guide surface even on the outside where the center of the roller protrudes beyond the open end surface of the outer joint member. As a result, the sliding range of the roller can be expanded to the opening side of the outer joint member.

  In the above-described configuration, “at least the roller guide surface” means that the inner peripheral surface of the outer joint member positioned between the adjacent roller guide surfaces can also have an arc shape.

  In the above-described configuration, it is desirable to continuously connect the arcuate opening end of the outer joint member and at least the roller guide surface adjacent thereto. In this way, the axial displacement of the roller between the roller guide surface and the arcuate opening end is smoothly performed. Note that “at least the roller guide surface” means that when the inner peripheral surface of the outer joint member located between adjacent roller guide surfaces is also arc-shaped, the inner peripheral surface adjacent to the arc-shaped inner peripheral surface It means to connect continuously.

  According to the present invention, at least the opening end of the roller guide surface of the outer joint member has an arc shape whose diameter increases toward the opening side, so that when the roller slides to the opening side of the outer joint member, Even at the outside where the center of the roller protrudes beyond the opening end surface of the outer joint member, the contact point between the roller and the roller guiding surface exists at the arc-shaped opening end of the roller guiding surface. As a result, the sliding range of the roller can be expanded to the opening side of the outer joint member. Further, if the slide range of the roller is made the same as the conventional one, the axial length of the outer joint member can be shortened, so that light weight and compactness can be realized.

  4 and 5 show an embodiment of a tripod type constant velocity universal joint according to the present invention. 4 shows a cross section with respect to the axis of the joint, and FIG. 5 shows a vertical section with respect to the axis of the joint. The tripod type constant velocity universal joint according to this embodiment includes an outer ring 10 that is an outer joint member, a tripod member 20 that is an inner joint member, and a roller 30 that is a rolling element.

  The outer ring 10 has a bottomed cylindrical shape with one open end, and one end of a rotary shaft (not shown) (not shown) is connected to the center of the bottom. Three track grooves 12 extending in the axial direction are formed on the inner peripheral surface of the outer ring 10 at equal intervals in the circumferential direction. Each track groove 12 has a pair of roller guide surfaces 14 facing each other on both sides thereof. The roller guide surface 14 has an arc-shaped cross section and extends linearly in the axial direction of the outer ring 10. The outer ring 10 has a recess 18 formed in the axial direction by reducing the thickness of a portion corresponding to the space between the track grooves 12 in order to reduce the weight.

  The tripod member 20 is formed by integrally forming three leg shafts 24 radially at equal intervals in the circumferential direction (120 ° intervals) on the outer peripheral surface of a cylindrical boss portion 22. The shaft end of the rotating shaft 50 (for example, a driven shaft) is connected to the shaft hole of the boss 22 by spline fitting. The tip end of each leg shaft 24 extends in the radial direction to the vicinity of the bottom surface of the track groove 12, and the outer peripheral surface thereof is a cylindrical surface.

  A roller 30 is disposed between the roller guide surface 14 of the track groove 12 of the outer ring 10 and the outer peripheral surface of the leg shaft 24 via needle rollers 40. The outer peripheral surface of the roller 30 has an arc shape in the longitudinal section, and is configured to be in line contact with the roller guide surface 14. On the other hand, the inner peripheral surface of the roller 30 is formed in a cylindrical shape. A plurality of needle rollers 40 are disposed between the inner peripheral surface of the roller 30 and the outer peripheral surface of the leg shaft 24 in a single row full roller state. The needle roller 40 is retained by a retaining ring 64 while being sandwiched between washers 60 and 62 disposed at the root portion and the distal end portion of the leg shaft 24.

  In the tripod type constant velocity universal joint of this embodiment, as shown in FIGS. 1 and 2, the diameter of the opening end portion 11 (cross hatched portion in the drawing) of the roller guide surface 14 of the outer ring 10 is increased toward the opening side. It has an arc shape. In this embodiment, the opening end 15 of the inner peripheral surface 13 located between the roller guide surfaces 14 of the outer ring 10 is also formed in an arc shape whose diameter increases toward the opening side. Thereby, it is possible to avoid the rotating shaft 50 connected to the tripod member 20 from interfering with the outer ring 10 when the joint takes a high operating angle. The arcuate open end 15 of the inner peripheral surface 13 of the outer ring 10 is not necessarily arcuate from the viewpoint of expanding the sliding range of the roller 30.

  3A is a simplified view of the track groove 12 formed on the inner periphery of the outer ring 10 as viewed from the joint axis, and FIG. 3B is a slide diagram showing the relationship of the operating angle with respect to the axial displacement. In the region surrounded by the trapezoid in the figure, the axial displacement and the operating angle can take predetermined values.

  In the conventional tripod type constant velocity universal joint, since the opening end of the roller guide surface 114 (see FIG. 8) of the outer ring 110 is a straight shape parallel to the axis (the broken line portion in FIG. 3A), the roller When 130 slides toward the opening side of the outer ring 110, the outermost position of the contact point X between the roller 130 and the roller guide surface 114 is a position where the center O of the roller 130 coincides with the opening end surface 116 of the outer ring 110 (see FIG. The position of the roller 30 indicated by the middle broken line).

  On the other hand, when the opening end 11 of the roller guide surface 14 of the outer ring 10 is formed in an arc shape [the solid line portion in FIG. The contact point Y between the roller 30 and the roller guide surface 14 exists at the arc-shaped open end 11 of the roller guide surface 14 even on the outside where the center O protrudes from the open end surface 16 of the outer ring 10. Thus, the outermost position of the contact point Y between the roller 30 and the roller guide surface 14 is an outer position where the center O of the roller 30 protrudes from the opening end surface 16 of the outer ring 10 (shown by a solid line in the figure). Position of roller 30). As a result, the sliding range of the roller 30 can be expanded toward the opening side of the outer ring 10 (shaded portion in FIG. 3B). If the sliding range of the roller 30 is the same as the conventional one, the axial length of the outer ring 10 can be shortened, so that a lightweight and compact design can be realized.

  The radius of curvature R at the open end 11 of the roller guide surface 14 of the outer ring 10 may be defined in the range of 2-15. If the radius of curvature R is smaller than 2, there is no effect of expanding the sliding range of the roller 30 toward the opening side of the outer ring 10, and if it is larger than 15, the circumferential clearance on the end face side becomes too large.

  In this embodiment, the arcuate opening end 11 of the roller guide surface 14 and the roller guide surface 14 adjacent thereto are continuously connected. In this way, the axial displacement of the roller 30 between the roller guide surface 14 and the arcuate opening end 11 is smoothly performed.

  As described above, since the sliding range of the roller 30 can be expanded toward the opening side of the outer ring 10 (see FIG. 3A), it is easy to secure a sliding amount at a high operating angle. The outer ring 10 in this embodiment can be easily manufactured only by adding a process of making the opening end 11 of the roller guide surface 14 in an arc shape with respect to the conventional product. Further, since the opening end 11 of the roller guide surface 14 of the outer ring 10 is formed in an arc shape, the outer ring 10 can be manufactured by forging, and further, the fitting internal parts can be incorporated into the outer ring 10. It becomes easy and can improve the incorporation property.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the claims within the scope of the present invention. Is possible.

In embodiment of the tripod type constant velocity universal joint which concerns on this invention, it is the partial side view seen from the opening side of the outer ring | wheel. It is sectional drawing which follows the AA line of FIG. In the embodiment of the present invention, (a) is a view of the roller guide surface and the roller viewed from the inner peripheral side of the outer ring, and (b) is a slide diagram showing the relationship of the operating angle with respect to the axial displacement. It is a longitudinal cross-sectional view which shows the whole structure of the tripod type | mold constant velocity universal joint in embodiment of this invention. It is a cross-sectional view which shows the whole structure of the tripod type | mold constant velocity universal joint in embodiment of this invention. It is a longitudinal cross-sectional view which shows the whole structure of the conventional tripod type constant velocity universal joint. It is a cross-sectional view which shows the whole structure of the conventional tripod type constant velocity universal joint. In the conventional tripod type constant velocity universal joint, (a) is a view of the roller guide surface and the roller as viewed from the inner peripheral side of the outer ring, and (b) is a slide diagram showing the relationship of the operating angle with respect to the axial displacement.

Explanation of symbols

10 Outer joint member (outer ring)
11 Open end of roller guide surface 12 Track groove 14 Roller guide surface 20 Tripod member 24 Leg shaft 30 Roller

Claims (2)

An outer joint member having a bottomed cylindrical shape with one end open, provided with three track grooves extending in the axial direction on the inner periphery, and provided with roller guide surfaces facing each other on the inner wall of each track groove, and the outer joint A tripod member having three leg shafts disposed inside the member and having a tip inserted into the track groove, and rotatably supported by the leg shaft and rolling into the track groove of the outer joint member A roller that is freely inserted and guided along the roller guide surface,
A tripod type constant velocity universal joint characterized in that at least an opening end portion of a roller guide surface of the outer joint member has an arc shape whose diameter increases toward the opening side.   The tripod type constant velocity universal joint according to claim 1, wherein the arcuate opening end of the outer joint member and at least the roller guide surface adjacent thereto are continuously connected.

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