JP2015140894A - Cross shaft joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cross shaft joint which can suppress shortage of oil films in a slide contact region by supplying a sufficient amount of lubricants between an inner bottom face of a bearing cap and an end face of a shaft part.SOLUTION: A cross shaft joint 1 comprises a cross shaft member 3 having four pieces of shaft parts 2 arranged in a cross shape, and cylindrical bearing caps 5 rotatably engaged with external peripheral faces of the shaft parts 2 via rolling bodies 4, and in which inner bottom faces 19 of the bearing caps 5 and end faces 2b of the shaft parts 2 opposing the inner bottom faces 19 slide in an annular slide-contact region with axial cores of the shaft parts 2 as centers. At each inner bottom face 19 of the bearing cap 5, there are formed a center recess 20 communicating with an oil hole 2c of the shaft part 2, an annular recess 21 in which one end of the rolling body 4 is arranged, and an annular protrusion 22 which slides with respect to the end face 2b of the shaft part 2 between the center recess 20 and the annular recess 21. The annular protrusion 22 comprises a plurality of oil grooves 25 which radially extend toward external peripheral directions, and are inclined to the inner bottom faces 19 at their groove bottoms, and annular grooves 26 which make the adjacent oil grooves 25 communicate with each other.

Description

  The present invention relates to a cross joint (universal joint) used in, for example, a drive shaft and a steering device of a vehicle.

  A drive shaft portion or the like of a vehicle includes a cross shaft member having four shaft portions arranged in a cross shape, and a bottomed cylindrical bearing cup that is rotatably fitted to the shaft portion via a needle bearing. The provided cross shaft joint is used. A rolling motion is performed by the needle bearing between the outer peripheral surface of the shaft portion and the inner peripheral surface of the bearing cup, and a sliding motion is performed between the end surface of the shaft portion and the inner bottom surface of the bearing cup. Yes. If oil film breakage occurs in this sliding contact area and friction during sliding increases, metallic bonding (adhesion) may occur. For this reason, it is necessary to ensure sufficient lubricity between the inner bottom surface of the bearing cup of the cross shaft member and the end surface of the shaft portion.

  For example, in the cross shaft joint of Patent Document 1, a grease nipple is provided at the center of the cross shaft member, and lubricating oil (grease) supplied through the grease nipple is formed at the center of each shaft. Is to be distributed to. A central recess communicating with the oil hole of the shaft portion and an annular recess in which one end of the needle bearing is disposed are formed on the inner bottom surface of the bearing cup, and an end surface of the shaft portion is formed between the central recess and the annular recess. An annular convex portion that slides is formed. Then, by forming a radial oil groove for holding grease on the annular convex portion, grease is supplied from the oil hole to the annular concave portion through the central concave portion, and on the sliding contact surface of the annular convex portion serving as a sliding contact area. An oil film is formed.

JP 2008-281185 A

  However, in the cross joint of Patent Document 1, if the grease is not sufficiently supplied between the inner bottom surface of the bearing cup and the end surface of the shaft portion, most of the grease flows into the needle bearing side from the annular recess. In some cases, the sliding contact surface of the annular convex portion serving as the sliding contact area is not sufficiently supplied. As a result, when the oil film is cut off on the sliding contact surface of the annular convex portion and the friction during sliding increases and adhesion occurs, the inner bottom surface of the bearing cup and the end surface of the shaft portion are damaged. .

  The present invention has been made to solve the above problems, and its purpose is to suppress the occurrence of oil film breakage in the sliding contact area by supplying sufficient lubricating oil to the inner bottom surface of the bearing cup. The object is to provide a cross joint that can be done.

  The invention according to claim 1 includes a cross shaft member having four shaft portions arranged in a cross shape, and a bottomed cylindrical shape that is rotatably fitted to the outer peripheral surface of each shaft portion via a rolling element. A bearing cup, and a cross shaft joint in which an end surface of the shaft portion facing the inner bottom surface and the inner bottom surface of the bearing cup slides in an annular sliding contact area around the shaft center of the shaft portion, The inner bottom surface of the bearing cup includes a central recess communicating with the oil hole of the shaft portion, an annular recess in which one end of the rolling element is disposed, and the shaft portion between the central recess and the annular recess. An annular convex portion is formed in sliding contact with the end surface, and the annular convex portion extends radially toward the outer circumferential direction and has a plurality of oil grooves whose groove bottom portions are inclined with respect to the inner bottom surface. And an annular groove communicating between the oil grooves.

  According to the invention of claim 1 configured as described above, the lubricating oil supplied to the oil hole of each shaft portion flows into the central concave portion communicating with the oil hole, and is supplied to the annular convex portion and the annular concave portion. The The lubricating oil supplied to the annular convex portion flows into each oil groove and flows toward the outer periphery of the bearing cup due to the centrifugal force acting in the axial direction of the shaft portion and the inclination of the groove bottom portion. Fill the groove. Further, the lubricating oil supplied to the annular recess lubricates the arrangement space of the rolling elements.

  Furthermore, since the lubricating oil filled in each oil groove flows into the oil groove adjacent in the circumferential direction via the annular groove, the lubricating oil is distributed to all the oil grooves without the lubricating oil being biased to the specific oil groove. Can be made.

  As described above, between the inner bottom surface of the bearing cup and the end surface of the shaft portion, the lubricating oil supplied from the oil hole to the annular convex portion and the inner surface of the bearing cup are stored and re-supplied to the end surface of the shaft portion. Since sufficient lubricating oil can be supplied by the lubricating oil to be produced, it is possible to suppress the occurrence of oil film breakage on the sliding contact surface of the annular convex portion.

  The invention according to claim 2 is the cross shaft joint according to claim 1, wherein a recess for oil reservoir is formed on the inner bottom surface at each of the connecting portions of the plurality of oil grooves and the annular groove. Features.

  According to the invention of claim 2 configured as described above, a part of the lubricating oil flowing in the oil groove and the annular groove can be held by the oil reservoir recess formed on the inner bottom surface of the bearing cup. It can be re-supplied to the sliding contact surface of the convex portion. Therefore, the occurrence of oil film breakage in the sliding contact area can be more reliably suppressed.

  According to the present invention, there is provided a cross joint that can suppress the occurrence of oil film breakage in the sliding contact area by supplying sufficient lubricating oil between the inner bottom surface of the bearing cup and the end surface of the shaft portion. can do.

It is a disassembled perspective view which shows the cross shaft coupling which concerns on embodiment of this invention. It is sectional drawing which expands and shows the axial part and bearing of FIG. It is a top view of the inner bottom face of the bearing cup of FIG. It is a partial side view of the drive shaft part provided with the cross shaft coupling of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of a cross joint according to the first embodiment of the present invention, and particularly shows a state in which a bearing 10 is cut in half.

  As shown in FIG. 1, the cross joint 1 of the present embodiment includes a cross shaft member 3 having four shaft portions 2, a bearing 10 attached to the shaft portion 2, and the bearing 10 and the shaft portion 2. And a seal member 6 for sealing between the two.

  For example, as shown in FIG. 4, the cross shaft joint 1 is used to connect two shafts 211 and 212 in a drive shaft portion of a vehicle and a steering device so that power can be transmitted. These shafts 211 and 212 are connected through a yoke member 213 and 214 connected to the bearing 10 so as to be swingable within a range of the joint angle θ.

  As shown in FIG. 1, the cross shaft member 3 has a main body portion 12 disposed in the center and four shaft portions 2 disposed in a cross shape from the main body portion 12. A grease nipple 15 is attached to the center of the main body 12, and grease as a lubricant injected from the grease nipple 15 is formed on the shaft center of each shaft portion 2 and communicates with each oil nipple 15. It is supplied to the hole 2c.

  FIG. 2 is an enlarged cross-sectional view showing the shaft portion 2 and the bearing 10, and is a cross-sectional view taken along the line AA in FIG. 3. The bearing 10 includes a bearing cup 5 and a large number of cylindrical rollers 4 as rolling elements on the outer peripheral surface 2 a of the shaft portion 2.

  The bearing cup 5 is formed in a bottomed cylindrical shape, and includes a cylindrical portion 8 and a bottom portion 9 that closes one axial end portion of the cylindrical portion 8. The cylindrical portion 8 of the bearing cup 5 is rotatably fitted to the outer peripheral surface 2 a of the shaft portion 2 via the cylindrical roller 4.

  Accordingly, the cylindrical roller 4 rolls with the inner peripheral surface 8a of the cylindrical portion 8 as the outer ring raceway portion and the outer peripheral surface 2a of the shaft portion 2 as the inner ring raceway portion, whereby the bearing cup 5 rotates about the axis X of the shaft portion 2. It is possible to turn freely. The inner bottom surface 19 of the bottom portion 9 of the bearing cup 5 slides in an annular sliding contact area with the end surface 2 b of the shaft portion 2 facing the inner bottom surface 19 of the bearing cup about the shaft center X of the shaft portion 2.

  FIG. 3 is a plan view of the inner bottom surface 19 of the bearing cup 5. As shown in FIGS. 2 and 3, a circular central recess 20 centered on the axis X of the bearing cup 5 is formed at the center of the inner bottom surface 19 of the bearing cup 5. It communicates with the oil hole 2 c of the part 2.

  An annular convex portion 22 serving as a sliding contact area is formed on the outer peripheral side of the central concave portion 20, and the top surface of the annular convex portion 22 is a sliding contact surface with respect to the end surface 2 b of the shaft portion 2. An annular recess 21 is formed on the outer peripheral side of the annular protrusion 22, and one end of the cylindrical roller 4 is disposed in the annular recess 21.

  As shown in FIG. 3, the annular convex portion 22 is formed with a plurality of oil grooves 25 that extend radially toward the outer peripheral direction. The groove bottom portion of the oil groove 25 is inclined with respect to the inner bottom surface 19, and the groove depth becomes deeper from the inner peripheral side to the outer peripheral side. Further, an annular groove 26 communicating with the oil grooves 25 adjacent in the circumferential direction is formed in the annular convex portion 22. The oil groove 25 and the annular groove 26 have a V-shaped cross section.

  A connecting portion between the oil groove 25 and the annular groove 26 is provided with an oil reservoir recess 27 formed in a circular recess. The recess 27 holds a part of the grease flowing through the oil groove 25 and the annular groove 26. The recess 27 is set to a size that can always hold a predetermined amount of grease.

  The grease supplied between the inner bottom surface 19 of the bearing cup 5 and the end surface 2b of the shaft portion 2 is drawn into the sliding contact area when the bearing cup 5 rotates about the axis X of the shaft portion 2. An oil film is formed on the sliding contact surface of the annular protrusion 22.

  According to the cross shaft joint 1 configured as described above, the grease supplied to the oil hole 2c of each shaft part 2 flows into the central recess 20 communicating with the oil hole 2c, and the annular protrusion 22 and It is supplied to the annular recess 21.

  The grease supplied to the annular convex portion 22 flows into each oil groove 25 and flows toward the outer peripheral direction of the bearing cup 5 by the centrifugal force acting in the axial direction of the shaft portion 2 and the inclination of the groove bottom portion. At the same time, the oil groove 25 is filled. Further, the grease supplied to the annular recess 21 lubricates the arrangement space of the cylindrical rollers 4.

  Further, the grease filling each oil groove 25 is held in the oil reservoir recess 27 and flows into the oil groove 25 adjacent in the circumferential direction via the annular groove 26. The grease can be spread over all the oil grooves 25 without the grease being biased.

  Thus, between the inner bottom surface 19 of the bearing cup 5 and the end surface 2b of the shaft portion 2, the grease supplied from the oil hole 2c to the annular convex portion 22 and the grease held in the oil reservoir concave portion 27 are provided. Since sufficient grease can be supplied by the grease accumulated on the inner bottom surface 19 of the bearing cup 5 and re-supplied to the end surface 2b of the shaft portion 2, an oil film breakage occurs on the sliding contact surface of the annular convex portion 22 Can be suppressed.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims. For example, in the above embodiment, 12 oil grooves are formed radially, but more oil grooves may be formed. A plurality of annular grooves may be formed. In addition, the cross joint according to the present invention can be applied to other drive shafts such as ships in addition to vehicles.

1: cross shaft joint, 2: shaft portion, 2a: outer peripheral surface, 2b: end surface, 2c: oil hole,
3: cross shaft member, 4: cylindrical roller (rolling element), 5: bearing cup, 6: seal member,
8: Cylindrical part, 9: Bottom part, 10: Bearing, 12: Body part, 15: Grease nipple,
19: inner bottom surface, 20: central concave portion, 21: annular concave portion, 22: annular convex portion,
25: oil groove, 26: annular groove, 27: recess, 211, 212: shaft,
213, 214: Yoke member, θ: joint angle, X: axial center

Claims (2)

A cross shaft member having four shaft portions arranged in a cross shape, and a bottomed cylindrical bearing cup that is rotatably fitted to the outer peripheral surface of each shaft portion via a rolling element, A cross shaft joint in which an end surface of the shaft portion facing the inner bottom surface of the cup and the inner bottom surface slides in an annular sliding contact area around the shaft center of the shaft portion,
The inner bottom surface of the bearing cup includes a central recess communicating with the oil hole of the shaft portion, an annular recess in which one end of the rolling element is disposed, and the shaft portion between the central recess and the annular recess. An end surface and an annular convex portion that slides are formed,
The annular convex portion includes a plurality of oil grooves extending radially in the outer peripheral direction and having a groove bottom portion inclined with respect to the inner bottom surface, and an annular groove communicating between the oil grooves adjacent in the circumferential direction. Cross shaft coupling characterized by.   2. The cross joint according to claim 1, wherein a concave portion for oil reservoir is formed on the inner bottom surface at a connecting portion between the plurality of oil grooves and the annular groove. 3.

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