JPH0121369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an improvement of a sliding tripod type constant velocity joint.

[Prior art]

First, a conventional sliding tripod type constant velocity joint will be explained with reference to FIGS. 5 to 7.

Fig. 5 is a sectional view of the main part of the joint, Fig. 6 is a perspective view of the housing in the joint, and Fig. 7 is a sectional view of the main part of the joint.
The figure is a graph showing the relationship between the rotation angle of the joint and the axial force.

In the figure, H is a cup-shaped housing, S is a shaft, 1 is a trunnion protruding from this shaft S, R is a spherical roller loosely fitted to this trunnion 1 via a needle 2, and 3 is a retainer. . The housing H has three concave raceways 4 extending in the axial direction formed on its inner surface, and the spherical roller R rolls and moves on the cylindrical surface 4a of the concave raceways 4 while sliding. It's getting old. Although not shown, a boot is attached between the housing H and the shaft S.

With this configuration, the relative movement of the housing H and the shaft S in the axial and angular directions is caused by the rolling and turning movements of the spherical roller R while sliding on the cylindrical surface 4a of the concave track 4. This makes it possible to transmit torque in the rotational direction between the spherical roller R and the concave raceway 4.

[Problem that the invention seeks to solve]

However, in this type of constant velocity joint, when the joint rotates under torque with a joint angle attached, due to the structure of the joint, as shown in Figure 7, the axis is rotated three times per rotation. It is known that a force is generated on the shaft S. This axial force is the joint angle of the joint,
Since it increases or decreases depending on the effects of transmission torque, etc., it becomes large, especially in recent high-output vehicles. In addition, if the generation cycle of this axial force matches the natural frequency of the vehicle body, suspension, etc., and an axial force large enough to induce resonance in the vehicle body is generated, it will cause lateral swaying vibrations to the occupants. There was a problem that it caused people to feel uncomfortable. For this reason, there was an inconvenience in the design of the vehicle that the joint angle had to be limited to a relatively small value.

In order to solve this problem, a proposal has been made in Japanese Patent Laid-Open No. 58-42832.

In this Japanese Patent Application Laid-Open No. 58-42832, a component (a strip-shaped member) similar in shape to the structural member (U-shaped centering member) of the present invention, which will be described in detail, is disclosed as part of the embodiments. However, according to the specification, this strip-like member is fixed in the axial direction with respect to the inner element, and is configured to be movable (slidable) with respect to the outer element. Furthermore, periodic axial load fluctuations are absorbed by the strip-like member to maintain balance within the joint.

As is clear from the above, this proposal has low frictional resistance in the sliding direction, which is the greatest advantage of the sliding tripod type constant velocity joint (the spherical roller "rolls" in the guide groove of the outer element).
This feature is lost because the relative displacement in the axial direction between the strip member and the outer element becomes ``sliding'', and the coefficient of friction increases significantly, sliding resistance becomes extremely large, and heat is generated. It has its drawbacks.

This invention attempts to solve these conventional problems by analyzing the factors that generate axial force and the degree of influence they have on axial force, as described below. , it is possible to reduce the axial force and prevent resonance of the vehicle body due to the axial force.

Explaining FIG. 9, first, there is a factor that generates the axial force, which is the following three frictional resistance forces. That is, a frictional resistance force f ₁ acting on the trunnion 1 when the spherical roller R rolls, a frictional resistance force f ₂ between the spherical roller R and the concave raceway 4 when it slides in the axial direction of the trunnion 1, Spherical roller R
is the frictional resistance force f ₃ with respect to the trunnion 1 (needle 2) when the trunnion 1 slides in the axial direction. In particular, it was found that the axial force caused by the latter two forces f ₂ and f ₃ was large. f ₁ , f ₂ , and f ₃ in FIG. 8 are graphs showing ratios indicating the degree of influence of axial force generation.

Furthermore, the mechanism of this axial force generation is explained in Sections 8 to 1.
The explanation using Figure 1 is as follows. Figure 9 shows the relative displacement between the spherical roller R and the concave raceway 4 when the joint is rotating. When moving from the area [] to the area [], the roller R tends to roll away from the concave raceway 4 due to the frictional resistance forces f ₂ and f ₃ in the area [], and moves to the area []. When it enters the concave raceway 4, it tries to roll away from the inside of the concave track 4 due to the frictional resistance forces f ₂ and f ₃ . However, since the spherical roller R is guided by the cylindrical surface 4a of the concave track 4 and moves along it, an external force that balances the frictional resistance forces f ₂ and f ₃ acts on the spherical roller R. . In addition, in FIG. 9, θ is the joint angle, and k is the rotation surface of the trunnion 1.

This external force is thought to be generated by movement of the contact point between the concave raceway 4 and the spherical roller R. In other words, if we consider the case where the spherical roller R is in the area [ ] as shown in Figure 9, the load will be reduced by moving from the original contact point A to B as shown in Figure 10.
A component force Ft of FA is generated. As shown in Fig. 11, this component force Ft is divided into a component force Ftsinθ that balances the sum of frictional resistance force f ₂ and frictional resistance force f ₃ and a component force Ftsinθ in the axis S direction. The component force Ftsinθ is
The addition of f ₁ will appear as the axial force. Note that when the spherical roller R comes to the boundary between the regions [] and [], sin θ=0, and therefore the axial component force Ftsin θ also becomes zero, and only f ₁ appears as the axial force.

As is clear from the above, the problems of the conventional constant velocity joint can be solved by reducing the frictional resistance forces f ₁ , f ₂ , and f ₃ . In other words, f ₁ has a sufficiently small frictional resistance due to "rolling", so
All that is left to do is to reduce f ₂ and f ₃ , in other words, reduce the component force Ftsinθ.

From this viewpoint, the present invention attempts to prevent resonance of the vehicle body due to axial force.

[Means for solving problems]

The tripod type constant velocity joint of the present invention is arranged between three concave raceways of the housing and a cylindrical roller that loosely fits into the three trunnions of the shaft and fits into the three concave raceways respectively. A U-shaped centering member is provided independently of the shaft so as to sandwich the roller, and the centering member has a cylindrical surface for sliding contact with the concave raceway. the housing is rotatable relative to the concave raceway;
The roller is attached so as not to be slidable in the axial direction, and the contact surface with the cylindrical roller is a flat surface, so that the flat surface is used as the rolling surface of the cylindrical roller.

〔Example〕

Embodiments of this invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a sectional view thereof, FIG. 2 is a front view of the main part, FIG. 3 is an enlarged view of the alignment member, and FIG. 4 is a diagram for explaining the operation of the embodiment.

In the figure, _H2 is a cup-shaped housing, and three concave raceways 11 extending in the axial direction are formed on the inner surface of the housing. S ₂ is a shaft, 12 is a trunnion protruding from this shaft S ₂ , R ₂ is a cylindrical roller loosely fitted to this trunnion 12 via a needle 13, 14 is a retainer, and the trunnion 12 shaft of the cylindrical roller R ₂ It is installed with a slight play in the direction. U
is a U-shaped centering member, which has a cylindrical surface r ₁ and a cylindrical roller R ₂ formed astride both side walls of the concave track 11.
The cylindrical roller _R2 is interposed between the roller and the roller R2.

The surface of the alignment member U on the concave raceway 11 side is a cylindrical surface r2 that slides in contact with the cylindrical surface _r1 of the concave raceway ₁₁ , and the surface on the cylindrical roller _R2 side moves in an arc due to the rotation of the trunnion 12. There is a plane p on which the roller R ₂ can roll. This member U is prevented from coming off the concave raceway 11 in the axial direction by caulking 15, and rotates relative to the housing _H2 within the concave raceway 11 as shown by the arrow. I'm starting to do that. Note that the alignment member U can rotate relative to the housing H ₂ within the concave track 11 and does not fall off from the housing H ₂ , so the method for attaching it to the housing H ₂ is as follows. Any means may be used as long as it is possible to prevent rotation and falling off. Note that k ₁ is the rotation surface of the trunnion 12.

With this configuration, the housing
The relative movement of H ₂ and axis S ₂ in the axial and angular directions is made possible by the cylindrical roller R ₂ rolling on the plane p of the alignment member U, and the transmission of torque during rotation is Between the cylindrical roller _R2 and the concave raceway 11,
This is possible via the centering member U.

That _is , when the joint rotates with a joint angle θ as shown in FIG. However, since the inner surface of the centering member U that comes into contact with the centering member U forms a plane p, the centering member U rolls while turning in an arc on this plane. At this time, the cylindrical roller R ₂ does not actively slide in the axial direction of the trunnion 12, but only slides within a range of play to prevent slight eccentric movement and rolling during joint rotation. . Therefore, since the line of contact between the cylindrical roller _R2 and the alignment member U always coincides with the generatrix of the cylindrical roller _R2 , the direction of the force generated on this line of contact always includes the axes of the three trunnions 12. Since it exists within a plane and no axial force is generated, there is almost no frictional resistance that affects the axial force.

Further, the movement of the shaft S ₂ in the axial direction with respect to the housing H ₂ is caused by the movement of the cylindrical roller R ₂ in the plane p of the alignment member U.
This is possible by rolling on the top, so both
There is almost no risk of sliding friction occurring between R ₂ and U, and therefore there is no risk of heat generation.

Note that edge loads can also be avoided by providing crowning in a direction perpendicular to the axial direction on at least one of the rolling surface of the cylindrical roller and the contact surface of the alignment member.

[Effect of idea]

As explained above, according to the present invention, a U-shaped alignment member is interposed between the cylindrical roller and the concave track of the housing, and this is attached to the housing so as to be relatively rotatable. Since the contact surface of the alignment member with the cylindrical roller is the rolling surface of the cylindrical roller, the alignment member can have an alignment function for the joint angle, and the axis of the joint, which is the cause of axial force, can be The generation of directional force can be reduced. Therefore, according to the present invention, resonance of the vehicle body due to the generation of axial force can be prevented.

Furthermore, even if the shaft is moved axially relative to the housing, the alignment member will not slide along the track in the axial direction, resulting in a significant reduction in friction.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is a sectional view of the main part thereof, FIG. 2 is a front view of the main part, FIG. 3 is a side view of the alignment member in the embodiment, and FIG. 5 to 11 show a conventional tripod type constant velocity joint, FIG. 5 is a sectional view of the main part thereof, and FIG. 6 is a perspective view of the housing in FIG. Figure 7 is a graph showing the combined axial force of each trunnion, Figure 8 is a graph showing the axial force per trunnion axis in Figure 5, Figures 9 and 10.
The figure and FIG. 11 are diagrams for explaining the operation. H ₂ ... Housing, 11 ... Concave raceway, S ₂ ...
Shaft, R ₂ ... Cylindrical roller, U ... Aligning member, r ₂ ...
Cylindrical surface, p...plane.

Claims (1)

[Claims] 1 The shaft and the cylindrical roller are fitted loosely into the three concave raceways of the housing and the three trunnions of the shaft so as to sandwich the cylindrical rollers, respectively. A U-shaped centering member provided independently is interposed therebetween, and the centering member has a cylindrical surface for sliding contact with the concave raceway, so that the housing is connected to the concave raceway. A tripod which is relatively rotatable and non-slidable in the axial direction, and whose contact surface with the cylindrical roller is a flat surface, so that the flat surface serves as the rolling surface of the cylindrical roller. Constant velocity joint.