JP4280650B2 - Cross joint - Google Patents

Description

  The present invention relates to a cruciform joint, and more particularly to a connecting member that supports a cruciform shaft and is joined to a rotating body by friction welding to connect the cruciform shaft and the rotating body.

  A cross joint used as a universal joint in a propeller shaft of a vehicle includes a cross shaft and a pair of connecting members that support the cross shaft. The pair of connecting members is also called a yoke member or the like, and each includes a yoke that supports any one of the cross shafts so as to be rotatable about the axis. Further, at least one of the pair of yoke members is joined to a rotating body such as a tube by friction welding.

As a method of manufacturing a propeller shaft including this cross joint, after assembling a cross joint comprising a spider (ie, a cross shaft), a cup, a bearing, a yoke member, etc., the end of the cross joint and the tube end that is a rotating body are assembled. A method of manufacturing a propeller shaft by friction welding is known (for example, Patent Document 1). According to this manufacturing method, even if the length of the tube changes, there is no change in the content of the process of assembling the cruciform joint, so there is no need to change the manufacturing equipment or change the setup in that process. Therefore, the manufacturing cost can be reduced as compared with the case where the cross joint is assembled after the tube and the yoke member joined to the tube are first pressed.
Japanese Patent Laid-Open No. 11-151621 JP 2003-113831 A JP-A-5-83464 JP 2003-240011 A

  In the manufacturing method described in Patent Document 1, the operating torque T (N · m) of the joint (that is, the cross joint) is an important quality characteristic before and after the tube end is friction welded to the end of the cross joint. ) Has changed. Here, the operating torque T is the torque when the cruciform joint is bent, and is the product of the load F (N) required for bending and the distance L (m) from the joint end to the axis of the cross shaft (F × N). The operating torque T is measured by a torque wrench, for example.

  This operating torque T is generated when the end surface of the cross shaft and the bottom surface of the cup that accommodates the cross shaft are brought into contact with each other. When the operating torque T is too high, vibration and abnormal noise are generated during power transmission. Or On the other hand, when the operating torque T is too low, it means that there is a gap between the end surface of the cross shaft and the bottom surface of the cup, and the cross joint is easily damaged. For this reason, it is required that the operating torque T falls within a certain range.

  FIG. 1 shows an operation torque T of a cross joint when a tube end is friction-welded to a cross joint after assembly in a cross joint for trucks and passenger cars as in the manufacturing method described in Patent Document 1. It is the figure compared before and after pressure welding. In FIG. 1, the vertical line indicates the fluctuation range, and the circle indicates the average value. As shown in FIG. 1, in both cases for trucks and passenger cars, the operating torque T after press contact is lower than that before press contact. It can also be seen that the reduction in operating torque T due to friction welding is greater for passenger cars than for trucks.

  Thus, since the operating torque T fluctuates due to friction welding, the manufacturing method disclosed in Patent Document 1 is applied only when the allowable range of the operating torque T is wide, such as a truck propeller shaft. Currently, the allowable range of the operating torque T of the cruciform joint is narrow, and the structure of the cruciform joint is less rigid than that for trucks, so that the fluctuation of the operating torque T due to friction welding is relatively large. However, the manufacturing method of Patent Document 1 could not be applied.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a cross joint that can reduce the change in the operating torque T due to the pressure contact of the rotating body.

  As a result of various studies to achieve the above object, the present inventor, as will be described in detail later, causes the operating torque T to decrease due to the friction welding between the end of the yoke member and the end of the tube. The tube end and the end of the yoke member joined to the tube end contract in the radial direction due to the temperature change during the friction welding, and the yoke member end contracts to the other end of the yoke member. It has been found that the cause is that the width of the formed yoke is increased. The present invention has been made based on such knowledge.

That is, according to a first aspect of the invention for achieving the above object, a cylindrical pressure contact portion joined to a rotating body by friction pressure welding and a support portion supporting the cross shaft are integrally formed, and the cross shaft and a rotating member to a cross joint which includes a coupling member for coupling, have accompanied the friction welding, by contracting deformation of the open end of the pressure contact portion, suppressing deformation that the support portion is deformed A propagation suppression structure is provided.

  According to a second aspect of the present invention, in the cross joint according to the first aspect, the deformation propagation suppressing structure is provided in the pressure contact portion in a circumferential direction, and has a lower rigidity than an opening end portion of the pressure contact portion. It is characterized by being.

  According to a third aspect of the present invention, in the cross joint according to the second aspect, the low-rigidity structure is made thinner than the opening end of the press-contact portion by being thinner than the opening end of the press-contact portion. It is characterized by.

  According to the first invention, even if the rotating body and the opening end portion of the pressure contact portion of the connecting member contract in the radial direction by friction welding, the deformation propagation suppression structure causes the shrinkage deformation of the pressure contact portion opening end portion due to the friction welding. As a result, the deformation of the support portion that supports the cross shaft is suppressed, so that the change in the operating torque T due to the pressure contact of the rotating body can be reduced.

  According to the second invention, even if the end of the rotating body and the press contact portion opening end of the connecting member contract in the radial direction by friction welding, the press contact portion is provided in the circumferential direction, and the press contact portion opening is provided. The low-rigidity structure, which is lower in rigidity than the end, absorbs the stress caused by the radial contraction of the press-contact opening end and suppresses the contraction from propagating to the support. A change in the operating torque T due to the pressure contact can be reduced.

  The third invention is an embodiment of the second invention, and the press contact portion is formed with a portion that is thinner than the opening end portion in the circumferential direction. The stress generated by the shrinkage is absorbed by the thinned portion, and the shrinkage is prevented from propagating to the support portion.

  The cross joint of the present invention is preferably used for a propeller shaft for a passenger car, but can also be applied to a propeller shaft for a vehicle other than a passenger car such as a propeller shaft for a truck. Further, the present invention can be applied to other than a propeller shaft such as a drive shaft.

  As a deformation propagation suppressing structure, there is a low-rigidity structure as in the second invention, but in addition to this, even if a shape that tends to concentrate stress is formed in a part of the pressure contact part, such as a stepped shape of the pressure contact part Good.

  Although the low-rigidity structure is provided over the circumferential direction of the press contact portion, it is not necessary to be provided in the entire circumferential direction, and may be provided only at a plurality of locations in the circumferential direction. Further, the low-rigidity structure may be provided only in one place in the axial direction of the press-contact portion, but may be provided in a plurality of places in the axial direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a front view of the cross joint 10 to which the present invention is applied. The cross joint 10 in FIG. 2 is for a passenger car and includes a joint yoke member 12, a flange yoke member 14, a cross shaft 16, a cup 18, and a needle 20.

  The joint yoke member 12 functions as a connecting member, is manufactured through forging and cutting, and has a structure in which a pair of yokes 26 functioning as a press contact portion 24 and a support portion protrude from opposite sides of the base portion 22 to each other. have. The pressure contact portion 24 has a cylindrical shape, and the end portion of the tube 25 that is a rotating body is joined to the opening end surface 24a by friction pressure welding in a state where the axial centers of the tubes 25 are aligned with each other. This friction welding is performed while either the tube 25 or the yoke 26 is rotated.

  The pair of yokes 26 protrude from the base 22 so as to face each other and in parallel with the axis of the press contact portion 24, and the shaft center penetrates perpendicularly to the axis of the press contact portion 24 at the distal end side. A hole 28 is formed. The cup 18 is fitted into the through hole 28. The cup 18 has a bottomed cylindrical shape that opens in one axial direction, and is manufactured by pressing. Further, the bottom side of the cup 18 is the outside (the side opposite to the other yoke 26), and the tip of the cross shaft 16 is fitted on the inner peripheral surface. A plurality of cylindrical needles 20 are arranged between the inner peripheral surface of the cup 18 and the outer peripheral surface of the tip of the cross shaft 16 so as to be able to roll.

  After the cup 18 is temporarily press-fitted into the through hole 28, the outer end portion of the through hole 28 is plastically deformed, whereby a plurality of caulking portions 30 are formed in the circumferential direction at the outer end portion of the through hole 28. . The caulking portion 30 prevents the cup 18 from coming out of the through hole 28. As described above, since the cup 18 is prohibited from coming out of the through hole 28, the cross shaft 16 in which the tip end portion of the shaft is accommodated in the cup 18 is supported by the yoke 26 so as to be rotatable around the axis. .

  The bottom portion of the cup 18 is clamped from both sides by the caulking portion 30 and the cross shaft 16, so that a predetermined amount is provided between the bottom surface of the cup 18 and the front end surface of the cross shaft 16 accommodated in the cup 18. A frictional resistance, that is, an operating torque T is generated. Further, the portion where the caulking portion 30 presses the bottom portion of the cup 18 is the peripheral edge of the bottom portion of the cup 18, so that the bottom portion of the cup 18 is slightly bent outward.

  The flange yoke member 14 also includes a base portion 32 and a pair of yokes 34 (only one is shown in FIG. 2) protruding from the base portion 32 in parallel with each other, and a through hole 36 is provided on the tip side of the yoke 34. It has been. The cup 18 is fitted into the through hole 36, and the caulking portion 38 is formed at the end of the through hole 36 by plastic deformation, so that the cup 18 is prevented from coming out of the through hole 36. . The cup 18 on the flange yoke member 14 side is provided with a needle (not shown) so that both ends of the shaft different from the side accommodated in the cup 18 on the joint yoke member 12 side of the cross shaft 16 can rotate about the axis. It is inserted through.

  Further, in the vicinity of the opening end surface 24a of the pressure contact portion 24 of the joint yoke member 12, a circle which is thinner than the opening end portion 24b over the entire circumferential direction and functions as a low rigidity structure, that is, a deformation propagation suppressing structure. An annular groove-shaped thin portion 24c is formed. FIG. 3 is an enlarged cross-sectional view of the press contact portion 24. As shown in FIG. 3, the thin portion 24 c of this embodiment is formed in the press-contact portion 24 near the opening end surface 24 a in the axial direction. Since the thin portion 24c is formed by cutting the outer periphery of the press contact portion 24, the outer peripheral surface of the press contact portion 24 has a portion where the thin portion 24c is formed indented radially inward. The inner diameter of the press contact portion 24 is the same in the axial direction including the portion where the thin portion 24c is formed. The thinner the thickness a of the thin portion 24c, the better as the low-rigidity structure. However, when the thickness is smaller than the thickness of the tube 25, the durability during use is reduced. Accordingly, the thickness a is preferably in a range thicker than the thickness of the tube 25.

  Next, the cross joint 10 of FIG. 2 will be described based on FIGS. 4 to 8 that the change in the operating torque T before and after the end of the tube 25 is pressed is small. FIG. 4 shows the width of the yoke of the joint yoke member and the outside of the open end of the press contact portion using a conventional cross joint having the same structure as the cross joint 10 of FIG. 2 except that the thin portion 24c is not formed. It is a figure which shows the result of having investigated the change of a diameter before and behind pressure welding. The width of the yoke is the distance between the tips of the pair of yokes, as shown in FIG. In FIG. 4, vertical lines and circles have the same meaning as in FIG. As shown in FIG. 4, in the case of the conventional cruciform joint, it can be seen that the outer diameter of the press contact portion opening end is reduced while the yoke width is increased due to the press contact. This is because the base part does not shrink in the radial direction, and when the end part of the press contact part which is one end part shrinks, the base part becomes a fulcrum, and the pair of yoke tips which are the other end part, This is considered to expand in the direction away from each other.

  FIG. 5 shows the outer diameter of the tube end and the pressure contact portion opening of the joint yoke member before, after, and after the pressure contact, after cutting (releasing) the joint with the tube using the conventional cross joint. It is a figure which shows the result of having investigated the change of the outer diameter of an edge. As shown in FIG. 5, both the outer diameter of the tube end and the outer diameter of the pressure contact opening end are reduced by pressure welding, but when the joint is cut, they change in the direction of returning to the original (that is, become larger). )

  FIG. 6 shows the results of examining changes in the operating torque T and the yoke width before, after, and after cutting (releasing) the joint with the tube using the above-described conventional cruciform joint. FIG. As shown in FIG. 6, the yoke width increases due to the pressure contact, and the operating torque T decreases. However, when the joint is cut, they change in the return direction, the yoke width decreases, and the operating torque decreases. It can be seen that T increases.

  From the results shown in FIGS. 4 to 6, the outer diameter of the tube end caused by the heat change during friction welding and the radial contraction of the opening end of the pressure welding portion enlarge the width of the yoke that is the other end. It can be seen that an increase in yoke width is associated with a decrease in operating torque T.

  Here, as described above, in the cross joint 10 of FIG. 2, the bottom portion of the cup 18 is bent, and the bending is caused by the caulking portion 30 pressing the peripheral edge of the bottom portion of the cup 18. Therefore, when the yoke width is increased and the caulking portion 30 is moved away from the cup 18, the amount of deflection d of the bottom surface of the cup 18 decreases. Further, the operating torque T is generated when the bottom portion of the cup 18 is clamped between the caulking portion 30 and the front end surface of the cross shaft 16 and the bottom surface of the cup 18 and the front end surface of the cross shaft 16 are brought into contact with each other. The same applies to the cross joints used in FIGS.

  Therefore, it is estimated that the operating torque T decreases as the yoke width increases and the amount d of deflection of the bottom surface of the cup decreases. Therefore, the relationship between the cup deflection amount d and the operating torque T was examined using a cross joint having the same configuration as the cross joint used in FIGS. The result is shown in FIG. As shown in FIG. 7, it can be seen that there is a positive correlation between the cup deflection d and the operating torque T. The correlation coefficient r was 0.94.

  4 to 7, as described above, in order to reduce the decrease in the operating torque T due to the friction welding, the contraction deformation of the tube end portion and the pressing portion end portion due to the friction welding is the end opposite to the pressing portion end portion. It can be seen that it is sufficient not to propagate to the yoke in the part. Therefore, in the cross joint 10 of FIG. 2, the pressure contact portion 24 is formed with a thin portion 34c having a lower rigidity than the opening end portion 24b by being thinner than the opening end portion 24b.

  FIG. 8 shows the change in the operating torque T before and after the tube pressure welding. The cross joint 10 to which the present invention shown in FIG. 2 is applied, that is, the cross joint in which the thin portion 24c is formed, and the conventional art in which the thin portion is not formed. It is a figure which shows the result compared with this cruciform joint. As shown in FIG. 8, it can be seen that when the thin portion 24c is formed, the decrease in the operating torque T due to the pressure contact is small. This is considered to be because when the end portion of the tube 25 and the open end portion 24b of the press contact portion 24 contract in the radial direction, the contraction stress is concentrated in the thin portion 24c.

  As described above, according to the present embodiment, even if the tube 25 and the open end 24b of the pressure contact portion 24 of the joint yoke member 12 contract in the radial direction due to friction welding, the thin wall portion 24c causes friction welding. Since the yoke 26 supporting the cross shaft 16 is restrained from being deformed by the contraction deformation of the opening end portion 24b of the pressure contact portion 24, the change in the operating torque T due to the pressure contact of the tube 25 can be reduced.

  That is, according to the present embodiment, even if the end portion of the tube 25 and the opening end portion 24b of the press contact portion 24 of the joint yoke member 12 contract in the radial direction by friction welding, the press contact portion 24 extends in the circumferential direction. The thin portion 24c provided and having a rigidity lower than that of the opening end portion 24b of the press contact portion 24 absorbs stress generated by the radial contraction of the open end portion 24b of the press contact portion 24, and the contraction is reduced to the yoke 26. Therefore, the change in the operating torque T due to the pressure contact of the tube 25 can be reduced.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the thin-walled portion 24c as the low-rigidity structure is formed in an annular groove shape by partially reducing the outer diameter of the press-contact portion 24. However, the press-contact except the open end portion 24b is used. The entire outer diameter of the portion 24 may be made smaller than the opening end 24b (FIG. 9), and the entire inner diameter of the press contact portion 24 except for the opening end 24b is made smaller than the opening end 24b. Alternatively, both the outer diameter and the inner diameter of the pressure contact portion 24 except for the opening end 24b may be smaller than the opening end 24b (FIG. 11). As shown in FIG. 12, a groove having a semispherical cross section including the axis of the press contact portion 24 may be formed as a low-rigidity structure, or the cross section may be wedge-shaped although not shown.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

In the cross joint for trucks and passenger cars, the operation torque T of the cross joint when the tube end is friction welded to the assembled cross joint is compared before and after the friction welding. It is a front view of a cross joint to which the present invention is applied. It is an expanded sectional view of the press-contact part of FIG. It is a figure which shows the result of having investigated the change before and after pressure welding of the width of the yoke of a joint yoke member, and the outer diameter of the press-contact part opening end using the conventional cross joint. Using the conventional cruciform joint, the outer diameter of the tube end and the outer diameter of the joint yoke member open end after cutting (release) the joint with the tube before, after, and after pressure welding It is a figure which shows the result of having investigated the change. It is a figure which shows the result of having investigated the change of the operation torque T and the yoke width after cut | disconnecting (release | release) the junction part with a tube before pressure welding, after pressure welding, and after pressure welding using the conventional cross joint. It is a figure which shows the result of having investigated the relationship between the bending amount d of a cup, and the operating torque T using the conventional cross joint. It is a figure which shows the result of having compared the change of the operating torque T before and behind tube pressure welding with the cross joint of FIG. 2, and the conventional cross joint in which the thin part is not formed. It is a figure which shows the aspect of the thin part different from FIG. It is a figure which shows the aspect of the thin part different from FIG. 3, FIG. It is a figure which shows the aspect of the thin part different from FIG.3, FIG.9, FIG.10. It is a figure which shows the aspect of a thin part different from FIG.3, FIG.9, FIG.10 and FIG.

Explanation of symbols

10: Cross joint, 12: Joint yoke member (connecting member), 16: Cross shaft, 24: Press contact portion, 24b: Open end portion, 24c: Thin wall portion (low rigidity structure, deformation propagation suppressing structure), 25: Tube ( Rotating body), 26: Yoke (supporting part)

Claims (3)

A cruciform joint comprising a cylindrical press-contact portion joined to the rotating body by friction welding and a support portion for supporting the cross shaft, and a connecting member for connecting the cross shaft and the rotating body. Because
There accompanied the friction welding, by contracting deformation of the open end of the pressure contact portion, cross joint, wherein the support portion is provided with a deformation propagation suppressing structure prevents the are deformed. 2. The cross joint according to claim 1, wherein the deformation propagation suppressing structure is a low-rigidity structure provided in a circumferential direction in the press-contact portion and having a lower rigidity than an opening end portion of the press-contact portion. . The cross joint according to claim 2, wherein the low-rigidity structure has a lower rigidity than the opening end portion of the press-contact portion by being thinner than the opening end portion of the press-contact portion.

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