EXTERNAL ROLLING DIAPHRAGM OVERMOULDED HIGH SPEED CONSTANT VELOCITY JOINT BOOT
A constant velocity joint boot assembly includes a boot-can having an axially extending main cylindrical body, a radially extending transition portion, an axially extending and generally cylindrical mounting portion. The radially extending transition portion intersects the axially extending main cylindrical body and the generally cylindrical mounting portion. A flexible boot member may be attached to an inner surface of at least two of the cylindrical body, the transition portion and the mounting portion at a coupling region.
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The present disclosure generally relates to constant velocity joints and, more particularly, to high-speed constant velocity joint and external rolling diaphragm boot cover assemblies.
BACKGROUNDConstant velocity joints and similar rotating couplings operate to transmit torque between two rotational members. The constant velocity joint typically includes an inner joint member for engagement with one rotational member, an outer joint member for engagement with the other rotational member, and a boot cover assembly or a grease cover to enclose and protect the rotating assembly positioned within the outer member during operation. Since the boot cover assembly is partially flexible, the boot cover assembly is able to seal around one of the rotating members while permitting articulation and relative axial movement between the two rotating members. The boot cover assembly provides a barrier to retain the grease in the internal cavity of the joint so as to reduce friction and extend the life of the joint. The boot cover assembly helps to seal out dirt, water and other contaminants to protect the functionality of the joint.
Constant velocity joints require constant lubrication (grease) to remain in operation in the environment in which they are utilized. Typically, such joints use a sealed system to contain the grease, the main component of which is the boot cover assembly that includes a boot and associated mounting can. Boots come in a variety of types. Some examples include convoluted, internal rolling diaphragm (IRD) and external rolling diaphragm (ERD). Particularly relating to IRD and ERD boots, the current industry standard is to have the diaphragm boot crimped onto the mounting can, and then to have the mounting can fit onto the joint. The mounting can and boot may be vulcanized together or crimped together at the top only, which allows grease that is under pressure from centrifugal forces during the joint rotation to be pushed between the sides of the boot and the mounting can (blow-out).
However, an important characteristic of the constant velocity joint is the ability of the joint to allow relative axial movement between two shafts while maintaining a seal to the outside environment. Typically, constant velocity joints include a seal groove that extends circumferentially about the outer surface of the outer member. This groove is generally machined or cut into the outer joint member, causing additional labor, cost and time. The groove provides a channel for receiving and positioning an o-ring type seal at a connection point between the boot assembly, boot-can and the outer member of the constant velocity joint. The seal is used to help prevent the blow-out phenomenon associated with the build-up of pressure.
Additionally, the centrifugal forces and friction associated with the internal components of the constant velocity joint assembly result in expansion or ballooning of the flexible boot cover as a result of the pressure created from heat and high speed operation. The deformation of the flexible boot cover may be affected by lubricant load, a pumping action of the lubricant due to constant velocity joint articulation, temperature, speed, release of gas volatiles from the grease, and the shape of the flexible boot. The constant expansion and contraction of the flexible member results in fatigue, wear and eventual failure of the flexible boot and ultimately the constant velocity joint. Typically, a vent is provided to relieve any pressure and minimize or eliminate the expansion of the flexible boot. However, this vent also allows dirt, water and other debris to enter the constant velocity joint. Specifically, venting the constant velocity joint can lead to lubricant leakage or loss, as well as the infiltration of contaminants into the joint, reducing its overall life.
What is needed, therefore, is a constant velocity joint and boot cover assembly that eliminates the need for a separate seal disposed about the outer surface of the outer member. Additionally, there is a need for a constant velocity joint and boot cover assembly that is configured to eliminate the need for a flexible boot vent.
SUMMARYThe present application discloses a constant velocity joint boot assembly. The constant velocity joint boot assembly may include a boot-can having an axially extending main cylindrical body, a radially extending transition portion, an axially extending and generally cylindrical mounting portion. The radially extending transition portion may intersect the axially extending main cylindrical body and the generally cylindrical mounting portion. A flexible boot member may be attached to an inner surface of at least two of the cylindrical body, the transition portion and the mounting portion at a coupling region for use with an associated constant velocity joint (CVJ). The present application may be applicable to a wide variety of CVJ's, including, but not limited to, plunging, tripod, fixed and high speed. The boot may be affixed to at least two internal surfaces of the boot-can by any known process such as, but not limited to, overmoulding, adhering and bonding. Specifically, the flexible boot may be affixed to a first joint connection end, such that the boot creates a seal between an end surface of the CVJ and the first end of the boot-can. By positioning the flexible boot between the boot-can and the CVJ, the need for an exteriorly positioned seal is eliminated.
Referring now to the drawings, preferred illustrative embodiments are shown in detail. Although the drawings represent some embodiments, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description:
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The generally cylindrical boot-can 130 may include an axially extending main cylindrical body 134, a radially extending transition portion 136, and an axially extending and generally cylindrical mounting portion 138. The boot-can 130 is formed of a first substantially rigid material, such as, but not limited to, aluminum, steel, carbon fiber and composite.
In one exemplary arrangement, the flexible boot 132 may be molded directly to the boot-can 130 to create a physical and/or a chemical bond at a coupling region 140. The coupling region 140 may extend from a portion of the axially extending main cylindrical body 134, across the radially extending transition portion 136 and terminating at a portion of the axially extending and generally cylindrical mounting portion 138. The coupling region 140 allows the bond between the flexible boot 132 and the boot-can 130 to occur on at least two surfaces. However, the exemplary arrangement, as shown in the drawings, details that the two surfaces are perpendicular.
As illustrated, the generally cylindrical mounting portion 138 may be configured to engage with and mate to an outer surface of the second end 126 of the outer joint member 116. Additionally, the second end 126 may also include an engagement groove 150 that extends circumferentially about the outer surface of the outer joint member 116. The engagement groove 150 may provide a tactile indicator or positive stop for engaging a lip 142 on the generally cylindrical mounting portion 138.
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The exemplary embodiments of
The present invention has been particularly shown and described with reference to the foregoing embodiment, which are merely illustrative of the best modes for carrying out the invention. It should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and nonobvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.
Claims
1. A constant velocity joint boot comprising:
- a boot-can having an axially extending main cylindrical body;
- a radially extending transition portion;
- an axially extending and generally cylindrical mounting portion, wherein the radially extending transition portion intersects the axially extending main cylindrical body and the generally cylindrical mounting portion; and
- a flexible boot member attached to an inner surface of at least two of the cylindrical body, the transition portion and the mounting portion at a coupling region.
2. The constant velocity joint boot of claim 1, wherein the flexible boot is configured as a unitary body with out apertures.
3. The constant velocity joint boot of claim 1, wherein the boot-can is configured as a unitary body.
4. The constant velocity joint system of claim 1, wherein the flexible boot and the boot-can are coupled at an approximate length of at least 8.5 mm to 14.5 mm across at least two of the main cylindrical body, the radially extending transition portion and the cylindrical mounting portion.
5. The constant velocity joint system of claim 1, wherein the flexible boot has a cross section that is approximately 1.5 mm to 3 mm thick at the coupling region.
6. The constant velocity joint system of claim 1, wherein the flexible boot includes an angled projection positioned adjacent an intersection between the radially extending portion and a generally cylindrical axially extending mounting portion.
7. The constant velocity joint system of claim 1, wherein the boot is overmoulded to the boot-can.
8. The constant velocity joint system of claim 1, wherein the angle is at least one of an angle greater than 90° and an angle less than 90°.
9. The constant velocity joint system of claim 1, wherein at least one of the main cylindrical body, the radially extending transition portion and the cylindrical mounting portion is generally rigid.
10. A constant velocity joint sealing system, comprising:
- a constant velocity joint, the joint having an inner joint member, and an outer joint member connected to said inner joint member; and
- a constant velocity joint boot assembly, the boot assembly having a flexible boot adhered to a boot-can at a coupling region, the coupling region having at least one axially extending surface and at least one radially extending surface intersecting the axially extending surface at an angle, wherein the flexible boot is selectively compressible to form a seal when the boot-can is fixedly secured with the outer joint member.
11. The constant velocity joint system of claim 9, wherein the two regions include a predetermined dimensional coupling region.
12. The constant velocity joint system of claim 9, wherein the flexible boot and the boot-can are adhered at an approximate length of at least 8.5 mm to 14.5 mm across at least two of the main cylindrical body, the radially extending transition portion and the cylindrical mounting portion.
13. The constant velocity joint system of claim 9, wherein the flexible boot has a cross section that is approximately 1.5 mm to 3 mm thick at the coupling region.
14. The constant velocity joint system of claim 9, wherein the flexible boot includes an angled projection positioned adjacent an intersection between the radially extending portion and a generally cylindrical axially extending mounting portion.
15. The constant velocity joint system of claim 9, wherein the flexible boot is configured as an external rolling diaphragm.
16. The constant velocity joint system of claim 9, wherein the angle is approximately 90°.
17. The constant velocity joint system of claim 9, wherein the angle ranges from 70°-110°.
18. The constant velocity joint system of claim 9, wherein the flexible boot is a unitary body without apertures, and the boot-can is a unitary body.
19. The constant velocity joint system of claim 9, wherein the constant velocity joint and the joint boot assembly are sealed and resilient to pressure differentiations when fixedly secured together, such that no atmospheric vent is included.
20. The constant velocity joint system of claim 9, wherein the angle is at least one of an angle greater than 90° and an angle less than 90°.
Type: Application
Filed: Sep 21, 2011
Publication Date: Aug 7, 2014
Applicant: GKN Driveline North America, Inc. (Auburn Hills, MI)
Inventors: Michael James Miller (White Lake, MI), Richard Alfred Compau (Holly, MI)
Application Number: 14/343,423