Constant Velocity Joint of Tripod Type

• US 20090011843A1
• Filed: 09/12/2008
• Published: 01/08/2009
• Est. Priority Date: 05/17/2007
• Status: Active Grant

• Current Assignee: WIA Corporation (Hyundai Mobis Co., Ltd.)
• Original Assignee: WIA Corporation (Hyundai Mobis Co., Ltd.)
• Inventors: Kim, Tae Hong, Oh, Seung Tark
• Granted Patent: US 8,025,575 B2
• Time in Patent Office: Days
• US Class Current: 464/147
• CPC Class Codes: F16D 2003/2026 with trunnion rings, i.e. with tripod joints having rollers supported by a ring on the trunnion
• CPC Class Codes: F16D 3/2055 having three pins, i.e. true tripod joints
• CPC Class Codes: Y10S 464/905 Torque transmitted via radially extending pin

Abstract

A constant velocity joint for a drive system of a vehicle comprises: a spider trunnion for transmitting torque between first and second shaft of the drive system, the spider trunnion including a spherical outer surface; and a roller assembly operatively attached on the spider trunnion, the roller assembly including an inner roller, an outer roller, and a plurality of needle rollers engaged between the inner and outer rollers, wherein the inner roller includes a tapered outer surface with a taper angle (θt), and the outer roller includes a tapered inner surface with the same taper angle (θt). The taper angle (θt) is preferably in a range from about 0.23° and to about 1.17°, and selected in consideration of both accommodating the inner roller to move without jamming in an entire effective movement range under presence of a maximum joint angle of the drive system, and preventing self separation of the roller assembly by jamming stop between the inner, outer and needle rollers due to the tapered structure of the rollers. The inner roller is preferably configured to have a ratio LL/RR1 in a range from about 0.11 to about 0.20, where LL is a distance from the center of the spider trunnion to a starting edge of the chamfer or recessed area of the inner roller at initial or neutral position thereof, and RR1 is a radius of the spherical surface of the spider trunnion.

Claims

1. A constant velocity joint for a drive system comprising:

a spider trunnion for transmitting torque between first and second shaft of the drive system, the spider trunnion including a spherical outer surface; and

a roller assembly operatively attached on the spider trunnion, the roller assembly including an inner roller, an outer roller, and a plurality of needle rollers engaged between the inner and outer rollers;

wherein the inner roller includes a tapered outer surface with a taper angle (θ

t), and the outer roller includes a tapered inner surface with the same taper angle (θ

t);

wherein the taper angle (θ

t) is in a range defined by the equation of;

2 tan<sup>−

1</sup>(0.030/Lt)<

θ

t<

2 tan<sup>−

1</sup>(0.3556/P1);

in which Lt is a length from an upper end surface of the inner roller to a lower end of the needle rollers, and P1 is a pitch circle diameter of the spider trunnion.

2. The constant velocity joint of claim 1, wherein the taper angle (θ

t) is from about 0.23° and

to about 1.17°

.

3. The constant velocity joint of claim 1, wherein the taper angle (θ

t) is determined in consideration of both accommodating the inner roller to move without jamming in an entire effective movement range under presence of a maximum joint angle of the drive system, and preventing self separation of the roller assembly by jamming stop between the inner, outer and needle rollers due to the tapered structure of the rollers.

4. The constant velocity joint of claim 1,

wherein the spherical outer surface of the spider trunnion has a radius (RR1), and the inner roller includes a concave inner contact surface with a radius (RR2);

wherein the inner roller further has a chamfer or recessed area starting from a lower edge of the concave inner contact surface;

wherein the inner roller has a dimension LL from the center of the spider trunnion to the starting edge of the chamfer or recessed area, and the inner roller is configured to have a ratio LL/RR1 in a range from {a+(RR1+0.005)sin(θ

t/2)}/RR1 to (0.21RR1−

0.009975)^1/2/RR1, in which “

a”

is a major radius in an elliptical contact area between the spider trunnion and inner roller.

5. The constant velocity joint of claim 4, wherein the ratio LL/RR1 is in a range from about 0.11 to about 0.16.

6. The constant velocity joint of claim 1,

wherein the spherical outer surface of the spider trunnion has a radius (RR1), and the inner roller includes a concave inner contact surface with a radius (RR2);

wherein the inner roller further has a chamfer or recessed area starting from a lower edge of the concave inner contact surface;

wherein the inner roller has a dimension LL from the center of the spider trunnion to the starting edge of the chamfer or recessed area, and the inner roller is configured to have a ratio LL/RR1 in a range from {a+(RR1+0.005)sin(θ

t/2)}/RR1 to (0.31RR1−

0.022475)^1/2/RR1, in which “

a”

is a major radius in an elliptical contact area between the spider trunnion and inner roller.

7. The constant velocity joint of claim 6, wherein the ratio LL/RR1 is in a range from about 0.11 to about 0.20.

8. A constant velocity joint for a drive system comprising:

a spider trunnion for transmitting torque between first and second shaft of the drive system, the spider trunnion including a spherical outer surface; and

a roller assembly operatively attached on the spider trunnion, the roller assembly including an inner roller, an outer roller, and a plurality of needle rollers engaged between the inner and outer rollers;

wherein the inner roller includes a tapered outer surface with a taper angle (θ

t), and the outer roller includes a tapered inner surface with the same taper angle (θ

t);

wherein the taper angle (θ

t) is in a range from about 0.23° and

to about 1.17°

.

9. The constant velocity joint of claim 8,

wherein the spherical outer surface of the spider trunnion has a radius (RR1), and the inner roller includes a concave inner contact surface with a radius (RR2);

wherein the inner roller further has a chamfer or recessed area starting from a lower edge of the concave inner contact surface;

wherein the inner roller has a dimension LL from the center of the spider trunnion to the starting edge of the chamfer or recessed area, and the inner roller is configured to have a ratio LL/RR1 in a range from about 0.11 to about 0.20.

10. The constant velocity joint of claim 9, wherein the ratio LL/RR1 is selected in consideration of a mechanical strength and durability of the inner roller in a manner by selecting the dimension LL to cover an elliptical contact area displaced downward due to the taper angle (θ

t), and also in consideration of an assembling and disassembling performance of the inner roller to the spider trunnion.

11. A method of assembling or disassembling a constant velocity joint comprising:

providing a spider trunnion, the spider trunnion having a spherical outer surface with a radius (RR1);

providing a roller assembly, the roller assembly having an inner roller, an outer roller, and a plurality of needle rollers, the inner roller having a tapered outer surface with a taper angle, and the outer roller having a tapered inner surface with a taper angle same as the taper angle of the inner roller;

wherein the inner roller includes a concave inner contact surface with a radius (RR2), the inner roller further has a chamfer or recessed area starting from a lower edge of the concave inner contact surface, and the inner roller has a dimension LL from the center of the spider trunnion to the starting edge of the chamfer or recessed area, and the inner roller is configured to have a ratio LL/RR1 in a range from about 0.11 to about 0.20;

tilting the inner roller to a degree;

placing one lower side of the inner roller onto the spherical surface of the spider trunnion; and

pushing and introducing an opposite lower side of the inner roller by hand or with the aid of an assembling tool through a top side of the spherical surface of the spider trunnion.

12. The method of claim 11 further comprising:

disassembling the inner roller from the spider trunnion by applying an upward load onto a lower side of the inner roller while without applying a substantial force onto the needle rollers and the outer roller.

13. The method of claim 12, wherein the upward load onto the lower side of the inner roller is applied by hand without using a specialized tool.

14. The method of claim 12, wherein the upward load onto the lower side of the inner roller is applied using a disassembling tool which is configured to apply a load onto a lower side of the inner roller while applying a counter load onto a top surface of the spider trunnion.