JP2518944Y2 - Constant velocity universal joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a constant velocity universal joint used for power transmission in an automobile or the like.

[Conventional technology]

There are various types of constant velocity universal joints.
Shown in the figure is a type capable of relative angular displacement and axial displacement between a drive shaft and a driven shaft, and includes an outer member (10), an inner member (20) and a ball (30). And the cage (40) are the main components. This type will be described below as an example. The outer member (10) and the inner member (20) are connected to a drive shaft or a driven shaft, respectively. The outer member (10) has guide grooves (11) in the axial direction at circumferentially equidistant positions on the inner diameter surface (12), and the inner member (20) is attached to the outer diameter surface (22) on the outer member (12). It has an axial guide groove (21) corresponding to the guide groove (11) of (10). These guide grooves (11, 2
1) form a pair, and each pair of guide grooves (11, 21) has a ball (3
0) are arranged one by one, and the outer member (10) and the inner member (2)
The torque is transmitted to and from (0). The cage (40) plays a role of ensuring uniform velocity by orienting the ball (30) in the bisector of the intersection angle when the drive shaft and the driven shaft rotate while intersecting each other. is there.

[Problems to be solved by the device]

As shown in an enlarged scale in FIG. 8, the inner diameter surface (42) of the cage (40) and the outer diameter surface (22) of the inner member (20) have apparently the same radius of curvature (Rc = Ri). However, the contact position between the cage (40) and the inner member (20) is often not constant due to variations in manufacturing tolerances and the like. Therefore, there are fluctuations in the sliding resistance at the contact portion between the cage (40) and the inner member (20), fluctuations in the sliding resistance due to changes over time, and the cage (40) and the inner member. Since there is only a slight gap between the contacting part with (20) and the lubricating oil is not held sufficiently, slippage between the cage (40) and the inner member (20), and eventually the bending movement of the entire joint is not smooth. There is a risk that

In particular, when the cage (40) slides in a wedge shape between the outer member (10) and the inner member (20) when sliding with an operating angle as shown in FIGS. 9 and 10. Due to the interposition, there is a problem that the inner member (20), the retainer (40) and the ball (30) are in a state of being locked to the outer member (10), so that the slide resistance increases. .

Therefore, an object of the present invention is to enable smooth angular displacement and axial displacement of the joint so that the locked state as described above is not reached. For that purpose, in particular, it is necessary to hold a lubricating oil film between the cage and the inner member at all times to ensure a smooth relative slip so that the balls can roll with a small resistance.

[Means for solving the problem]

This invention has solved the problem by forming graduations at both axial ends of either or both of the inner diameter surface of the cage and the outer diameter surface of the inner member.

That is, the constant velocity universal joint of the present invention comprises an outer member having an axial guide groove formed on the inner diameter surface, an inner member having an axial guide groove formed on the outer diameter surface, a guide groove of the outer member and an outer member. The inner member includes a ball that is interposed between the inner member and the guide groove of the inner member to transmit torque, and a retainer that holds the ball between the inner diameter surface of the outer member and the outer diameter surface of the inner member. The outer diameter surface and the inner diameter surface of the cage that is in contact with the outer diameter surface are formed with slacks at both end portions.

Generally, sloppyness means a finishing method in which a machined surface is gradually retreated toward the end rather than a regular surface, and a part finished in such a manner. Therefore, the dimension change does not occur as sharply as the so-called chamfering, but a case where the finished surface gradually changes with a constant curvature like crowning known in the field of roller bearings is also included in the smoothing.

The inner diameter surface of the cage and the outer diameter surface of the inner member shall be angular contacts. In that case, the inner diameter surface of the cage is formed by a pair of surfaces that are symmetrical with respect to the width center, and the cross-sectional shape of each surface is concave arc (claim 2), linear (claim 3) or convex arc (claim). 4).

Further, a cylindrical portion can be formed in the center of the inner diameter surface of the cage in the axial direction (claim 5). In this case, the diameter of the cylindrical portion is larger than the diameter of the outer diameter surface of the inner member (claim 6) or equal within a normal tolerance range (claim 7).

[Action]

By forming the graduations on both ends of at least one of the outer diameter surface of the inner member and the inner diameter surface of the cage, the lubricating oil film is always held between the both. That is, since there is slack, both members slide smoothly without being caught in each other, and the lubricating oil on the surface of the other party is not scraped off. In addition, the presence of slacks at both ends makes it easier for the lubricating oil to be drawn into the gap between the two, and the lubricating oil thus drawn is held in the same gap by capillary action, and a lubricating oil film is always formed. To do. In this way, as a result of keeping the lubricating oil film between the inner member and the cage,
Both are less likely to fall into a locked state, and therefore the ball can roll with less resistance.

As already mentioned, when the constant velocity universal joint takes an operating angle,
The inner member and the retainer can move relative to each other in the axial direction as well as the relative rotation. Conventionally, in such a case, the cage may be wedged between the inner member and the outer member to increase the slide resistance. Since the presence of the above-described structure does not cause a problem such as biting, the metal film between the inner member and the cage is prevented because the lubricating oil film is maintained, and a smooth relative displacement is guaranteed.

By making the contact relationship between the cage and the inner member to be an angular contact, the two are always in contact with each other at a constant position, so that unstable elements such as variations in sliding resistance are reduced.

When the inner diameter surface of the cage is formed by a pair of surfaces which are symmetrical with respect to the width center and whose cross section is a convex arc (claim 4), the cage itself constitutes a slack depending on the curvature of these surfaces.

The cylindrical portion (claims 5 to 7) formed in the axially central portion of the inner diameter surface of the cage not only facilitates the processing but also serves as an oil sump.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 are views showing a cross section of the contact portion between the inner member (20) and the retainer (40) merely for explaining the position where the flattening (26, 46) should be provided. That is, the slack is formed at both ends of the inner diameter surface (42) of the cage (40) (Fig. 1) or both ends of the outer diameter surface (22) of the inner member (20) (second
It is also possible to provide flats (46, 26) on the inner surface (42) of the cage (40) and on the outer surface (22) of the inner member (20), respectively. Although the inner diameter surface (42) of the cage (40) and the outer diameter surface (22) of the inner member (20) are in spherical contact with each other in FIGS. 1 and 2,
In all the embodiments shown in FIGS. 3A, 3B, 4A, 4B, 5, and 6, the contact relationship between the cage (40) and the inner member (20) is angular. Make a contact.

First, in the embodiment shown in FIG. 3A, the inner diameter surface of the retainer (40) is formed by a pair of concave spherical surfaces symmetrical with respect to the width center, in other words, a surface (42a) having a concave arc shape in cross section. There is. Each concave spherical surface (42a) has a center of curvature at a point that is equidistant from the width center of the inner diameter surface of the cage (40) in the axial direction,
The inner member (20) has a larger radius of curvature (Rc) than the radius (Ri) of the outer diameter surface (22).

FIG. 4A shows that the inner diameter surface of the cage (40) is a pair of conical surfaces,
In other words, it shows an example in which the cross section is formed by a straight surface (42b).

Further, FIGS. 3B and 4B show that in the embodiment of FIGS. 3A and 4A described above, a cylindrical portion (48) is provided at the central portion in the axial direction of the inner diameter surface of the cage (40), respectively. The formed example is shown. The cylindrical portion (48) provides a tool relief when machining the inner diameter surface of the retainer (40), and the inner member (2).
A space that functions as an oil reservoir for holding the lubricating oil is secured between the outer diameter surface (22) and the outer diameter surface (22) of (0), which contributes to holding the lubricating oil film and improving the lubricating performance.

In the embodiment shown in FIG. 5, the inner diameter surface of the retainer (40) is a pair of convex arc-shaped surfaces (42c) located on both sides of the cylindrical portion (48) at the central portion in the axial direction. Has been formed. In this case, the curvature of the surface (42c) itself constitutes the flattening.

The embodiment shown in FIGS. 3B, 4B and 5 is such that the diameter of the cylindrical portion (48) is made larger than the diameter (2Ri) of the outer diameter surface (22) of the inner member (20). However, as illustrated in FIG. 6, the cylindrical portion (48) may have the same diameter as the outer diameter surface (22) of the inner member (20) within a normal tolerance range. In this case, the inner member (20) is normally in contact only with this cylindrical portion (48), and when the cage (40) and the inner member (20) move relative to each other, either It touches the surface (42c).

[Effect of device]

As described above, according to the present invention, since the blunting is provided at both end portions of either or both of the outer diameter surface of the inner member and the inner diameter surface of the cage, there is a risk that the edges of the both members may lose contact with each other. And therefore also
The lubricating oil on the surface of the other party will not be scraped off, and the presence of the slack will facilitate the drawing of the lubricating oil into the gap between the two. As a result, the lubricating oil film is always held between them, preventing metal contact between the inner member and the cage and ensuring smooth relative slip, so the ball can roll with less resistance and become locked. It is possible to avoid reaching.

In addition, the cage and the inner member are made into angular contact to realize a stable contact relationship between them, and in combination with the smoothing provided to secure the lubricating oil film, smooth angular displacement with less resistance and It becomes possible to take axial displacement.

[Brief description of drawings]

FIGS. 1 and 2 are partial cross-sectional views showing a contact portion between an inner member and a cage for explaining a position where a slack is to be provided, and FIGS. 3A and 4A are cross-sectional views of main parts showing different embodiments. FIG. 3, FIG. 3B and FIG. 4B are cross-sectional views of a main part showing still another embodiment, FIG. 5 and FIG. 6 are cross-sectional views of a main part showing still another embodiment, and FIG. FIG. 8 is an enlarged sectional view, and FIGS. 9 and 10 are sectional views taken at an operating angle. 10: Outer member 20: Inner member 22: Outer diameter surface 26: Flattening 30: Ball 40: Retainer 42: Inner diameter surface 42a: Cross-section concave arc surface 42b: Cross-section straight surface 42c: Cross-section surface Convex arc surface 46: Scatter 48: Cylindrical part

Claims (7)

(57) [Scope of utility model registration request] 1. An outer member having an axial guide groove formed on an inner diameter surface thereof, an inner member having an axial guide groove formed on an outer diameter surface thereof, a guide groove of an outer member and a guide groove of an inner member. And a cage that holds the ball between the inner diameter surface of the outer member and the outer diameter surface of the inner member. At least one of the inner diameter surfaces of the cages that are in contact with each other, blunting is formed at both end portions, and the inner diameter surface of the cage and the outer diameter surface of the inner member are
A constant velocity universal joint that makes angular contact at positions equidistant from the center of the width of the inner diameter surface of the cage in the axial direction. 2. The constant velocity universal joint according to claim 1, wherein the inner diameter surface of the cage is a pair of symmetrical symmetrical surfaces with respect to the width center and has a concave arc-shaped surface. 3. The constant velocity universal joint according to claim 1, wherein the inner diameter surface of the cage is a pair of surfaces having a linear cross section and symmetrical with respect to the width center. 4. The constant velocity universal joint according to claim 1, wherein the inner diameter surface of the cage is a pair of symmetrical symmetrical cross-sections with respect to the width center. 5. The constant velocity universal joint according to claim 1, wherein a cylindrical portion is formed at the axial center of the inner diameter surface of the cage. 6. The constant velocity universal joint according to claim 5, wherein the diameter of the cylindrical portion is larger than the diameter of the outer diameter surface of the inner member. 7. The constant velocity universal joint according to claim 5, wherein the diameter of the cylindrical portion is equal to the diameter of the outer diameter surface of the inner member.