DIFFERENTIAL AND THRUST WASHER THEREFOR
A thrust washer and a differential containing a thrust washer. The differential has a housing, a spider with a plurality of spider arms, and one or more spider gears. The thrust washer includes a body comprising an annular shape having a width configured to approximately match a width of the one or more spider gears and further configured to a have a slope along the width configured to conform with an inner diameter of the housing and at least one engagement mechanism to engage with at least two of the plurality of spider arms to engage the thrust washer with the spider to approximately prevent the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.
This application is a continuation of U.S. patent application Ser. No. 17/381,697, filed Jul. 21, 2021, which is a continuation of PCT Patent Application No. PCT/CA2020/050068, filed Jan. 21, 2020, which claims priority to and the benefit of U.S. Provisional Patent Application 62/794,895 filed Jan. 21, 2019, the content of which are hereby incorporated herein by reference.
TECHNICAL FIELDThis document relates to a differential and a thrust washer therefor, and, in particular, to a thrust washer for use with spider gears in a differential.
BACKGROUNDMany types of vehicles use a differential to control the distribution of drive power to drive wheels and the like. In a typical differential, one or more pinion gears (sometimes called “pinions”, “spider gears” or “planetary gears”) are connected with a ring/driving gear via a spider and configured to interact with side gears to provide a variable distribution of power to drive wheels. The side gears each drive an axle which supports the drive wheels of the vehicle. The side gears and the spider gears are supported in a housing. In order to protect the housing and the spider gears, the differential will generally also include one or more washers, generally called thrust washers, located between the spider gears and the housing. Conventional thrust washers are designed in various ways.
Even with thrust washers having locking mechanisms of the type described above there can be an issue with housing or washer wear or failure due to the high forces encountered in the differential during operation. As such, there is a need for an improved differential and thrust washer for use in differentials that provides better protection for the mechanism and a longer life for the differential.
SUMMARYAccording to an aspect herein there is provided a thrust washer for a differential having a housing and an assembly of a spider and one or more spider gears, the thrust washer including: a body having an annular shape and a width configured to approximately match with a width of/cover the one or more spider gears and further configured to engage with the spider to prevent or reduce the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.
In some cases, the spider includes at least one spider arm and the thrust washer includes at least one engagement mechanism having a size and a shape to engage with an outer diameter of the at least one arm to engage the thrust washer with the spider. In some cases, the at least one spider arm includes four arms, the at least one engagement mechanism includes four apertures, and each of the four apertures are positioned and oriented to engage a respective one of the four arms when the thrust washer is installed in the differential.
In some cases, the thrust washer includes a slope along the width configured to conform with an inner diameter of the housing. In some cases, the slope along the width also conforms to a shape of the spider gears.
In some cases, the thrust washer includes a first portion and a second portion, and the first portion and the second portion are configured to assemble around the spider and the spider gears. In some cases, the slope is configured to engage with the housing to reduce separation of the first portion and the second portion. In some cases, the first portion and the second portion are configured to provide a gap between the first portion and the second portion when assembled to allow the flow of debris or the like. In some cases, the thrust washer has a continuous ring shape. In some cases, the thrust washer includes a gap across the width of the thrust washer. In some cases, the thrust washer is a single contiguous body.
According to an aspect herein there is provided a differential including: a housing; a spider and one or more spider gears; at least two side gears positioned and oriented to engage the one or more spider gears within the housing; and a thrust washer positioned between the housing and the one or more spider gears, the thrust washer including: a body having an annular shape and a width configured to approximately cover the one or more spider gears and and further configured to engage with the spider to prevent the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.
In some cases, the spider comprises at least one spider arm and wherein the thrust washer includes at least one engagement mechanism having a size and a shape to engage with an outer diameter of the at least one spider arm to engage the thrust washer with the spider. In some cases, the at least one spider arm includes four arms, the at least one engagement mechanism includes four apertures, and each of the four apertures are positioned and oriented to engage a respective one of the four arms when the thrust washer is installed in the differential.
In some cases, the thrust washer further includes a slope along the width configured to conform with an inner diameter of the housing. In some cases, the slope along the width also conforms to a shape of the spider gears.
In some cases, the thrust washer includes a first portion and a second portion, and the first portion and the second portion are configured to assemble around the spider and the spider gears. In some cases, the slope is configured to engage with the housing to reduce separation of the first portion and the second portion. In some cases, the first portion and the second portion are configured to provide a gap between the first portion and the second portion to allow the flow of debris or the like.
In some cases, the thrust washer has a continuous ring shape. In some cases, the thrust washer includes a gap across the width of the thrust washer. In some cases, the thrust washer is a single contiguous body.
Other aspects and features of the thrust washer will become apparent, to those ordinarily skilled in the art, upon review of the following description of some exemplary embodiments.
The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification and are not intended to limit the scope of what is taught in any way.
Various systems, apparatuses or methods will be described herein to provide example embodiment(s). No embodiment described below is intended to limit any claimed invention. The claims are not limited to systems, apparatuses or methods having all of the features of any one embodiment or to features common to multiple or all of the embodiments described herein. A claim may include features taken from any embodiment or a selection of embodiments as would be understood by one of skill in the art. The applicants, inventors or owners reserve all rights that they may have in any invention disclosed herein, for example the right to claim such an invention in a continuing application and do not intend to abandon, disclaim or dedicate to the public any such invention by its disclosure in this document.
The side gears 215 are supported in the housing 210. The spider gears 225 are each mounted on one of the arms 222 (i.e. stub shafts or posts) of the spider 220. In other words, the spider gears 225 and the spider 220 form a spider gear assembly. The spider 220 is also supported in the housing 210 such that the spider gears 225 mesh with the side gears 215. The thrust washer 230 is provided such that the body of the thrust washer engages with the spider 220 and is located between the spider gears 225 and the housing 210.
Each spider gear 225 includes an outer edge (i.e. back face) 227. Some locations of the outer edge 227 of spider gears 225 are denoted in
In this embodiment, the thrust washer 230, that is, the first thrust washer portion 230a, and/or the second thrust washer portion 230b, are held/locked in place by engaging an outer diameter (OD) of at least one of the arms 222 of the spider 220 via the indentations 232 (in the present embodiment, the thrust washer 230 engages all four arms 222). Each portion of the thrust washer 230 is controlled from moving axially inward by the interaction with the arms 222, as well as with each other. The engagement of the thrust washer 230 to the arms 222 prevents or reduces rotation of the thrust washer 230 against the housing 210. Since the thrust washer does not rotate against the housing, the surface roughness or strength of the housing 210 should not significantly affect the wear resistance or durability of the housing 210. Further, each of the first thrust washer portion 230a, and/or the second thrust washer portion 230b are prevented from moving radially and/or axially outward by abutting against the ID of the differential housing 210 and due to the annular shape. In operation, the outward force of the spider gears 225 pushes the thrust washer 230 outward against the housing 210, and the housing 210 prevents separation of the portions of the thrust washer 230. Examples of the orientation of axial inward and axial outward movement are depicted in
As noted above, the purpose of a thrust washer is to protect against the thrust and rotary action between the spider gear and the differential housing. The arrangement of the thrust washer 230 of the present embodiment holds/locks the thrust washer 230 to the spider 220 via the indentations 232 (an engagement mechanism) while generally covering the spider gears 225 to provide protection to the housing 210.
For contrast,
In the case of the conventional thrust washer 130, a first reaction force 310 prevents the conventional thrust washer 130 from rotating. In this case, the conventional thrust washer 130 reacts to the torque 300 by applying a force against the housing of the differential via the two tabs 150 while the tabs 150 act as a cantilevered beam and are subjected to relatively high bending and contact stresses.
In the case of the first portion of the thrust washer 230a, a second reaction force 320 prevents the first portion of the thrust washer 230a from rotating. In the present embodiment, the first portion of the thrust washer 230a is a ring/cylinder, and therefore the thrust washer is similar to a simply supported beam that is constrained on both ends when force is applied. In this case, the thrust washer reacts to the torque 300 by applying a force against adjacent arms of the spider which is opposed by the second reaction force 320. Further, the second reaction force 320 is located at a post of the spider adjacent to the given spider gear which is the furthest position relative to the centre of rotation of the spider gear, which minimizes the reaction force 320. The torque 300 may also be prevented from causing rotation of the first portion of the thrust washer 230a by a reaction force arising between the housing of the differential and the first portion of the thrust washer 230a and/or the second portion 230b of the thrust washer.
Due to the large moment arm between the axis of rotation of the first portion of the thrust washer 230a and the location of the second reaction force 320, the force on the first portion of the thrust washer 230a is less than the force on the conventional thrust washer 130.
A typical flow path for oil in the housing is shown in
Although the illustrated embodiments generally relate to a spider having 4 stub shafts, one of skill in the art will understand that the spider may have another number of stub shafts such as 2, 3, 4 or more. The embodiments of a thrust washer described herein can be used to withstand thrust from a variety of spider gear systems. An example is shown in
Spider 1420 may be formed by assembling the two spider portions 1424. Each spider portion 1424 includes a groove 1426. Each groove 1426 is configured to allow a first groove 1426 of a first spider portion 1424 to interface with a second groove 1426 from a second spider portion 1424 to form the spider 1420. Each groove 1426 includes a notch 1428 to allow the first spider portion 1424 and the second spider portion 1424 to slide past one another during assembly of the spider 1420. The spider 1420 may be assembled with the spider gears 1425 generally enclosed by the thrust washer 1430. The spider 1420 may be assembled as part of a method of assembling a differential.
A person having ordinary skill in the art, with the benefit of this disclosure, will appreciate that, in alternative embodiments, a thrust washer may be a single portion that includes a slit, gap, joint, hinge, or the like as a part of the engagement mechanism or of the thrust washer itself to allow reversible movement of at least a portion of the thrust washer to allow assembly of the thrust washer together with the spider and spider gears. While in some embodiments of the present disclosure the thrust washer comprises two portions that are configured to meet along a common circumferential surface, in alternative embodiments the thrust washer may include portions that are of unequal size, that are configured to mate together in alternative arrangements (e.g. overlapping segments), and may include alternative engagement mechanisms, such as aperatures/indentations of unequal size and/or shape.
A further intended advantage of the thrust washers of the present disclosure is that a thrust washer engages the spider arms at multiple locations and covers all spider gears rather than providing a plurality of conventional thrust washers.
In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the example embodiments. However, it will be apparent to one skilled in the art that these specific details may not be required. In other instances, well-known structures may be shown in block diagram form in order not to obscure the understanding. It will be further understood that, where appropriate, aspects from one embodiment may be used in other embodiments.
What has been described is merely illustrative of the application of some embodiments. It will be understood that elements of each embodiment may be combined with elements of other embodiments and that not every element in an embodiment is required. For example, each embodiment may include more or fewer elements as would be understood by one of skill in the art on reading this description. Further, other systems, apparatus and methods can be implemented by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the following claims.
Claims
1. A thrust washer for a differential having a housing, a spider comprising a plurality of spider arms, and one or more spider gears, the thrust washer comprising:
- a thrust washer body comprising an annular shape having a width configured to approximately match a width of the one or more spider gears and further configured to a have a slope along the width configured to conform with an inner diameter of the housing; and
- at least one engagement mechanism configured to engage with at least two of the plurality of spider arms to engage the thrust washer with the spider to approximately prevent the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.
2. The thrust washer of claim 1, wherein the plurality of spider arms comprises four spider arms, the at least one engagement mechanism comprises four apertures, and each of the four apertures are positioned and oriented to engage a respective one of the four spider arms when the thrust washer is installed in the differential.
3. The thrust washer of claim 1, wherein the slope along the width also conforms to a shape of the spider gears.
4. The thrust washer of claim 1, wherein the thrust washer body comprises a first portion and a second portion, wherein the first portion and the second portion are connected and configured to assemble around the spider and the spider gears.
5. The thrust washer of claim 4, wherein the slope is configured to engage with the housing to reduce separation of the first portion and the second portion.
6. The thrust washer of claims 4, wherein the first portion and the second portion are configured to provide a gap between the first portion and the second portion when assembled to allow the flow of debris or the like.
7. The thrust washer of claim 1, wherein the thrust washer has a continuous ring shape.
8. A differential comprising:
- a housing;
- a spider comprising a plurality of spider arms;
- one or more spider gears configured to be installed on the spider;
- at least two side gears positioned and oriented to engage the one or more spider gears within the housing; and
- a thrust washer positioned between the housing and the at least one spider gear, the thrust washer comprising: a thrust washer body comprising an annular shape having a width configured to approximately match a width of the one or more spider gears and further configured to a have a slope along the width configured to conform with an inner diameter of the housing; and at least one engagement mechanism configured to engage with at least two of the plurality of spider arms to engage the thrust washer with the spider to approximately prevent the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.
9. The differential of claim 8, wherein the plurality of spider arms comprises four spider arms, the at least one engagement mechanism comprises four apertures, and wherein each of the four apertures are positioned and oriented to engage a respective one of the four spider arms when the thrust washer is installed in the differential.
10. The differential of claim 8, wherein the slope along the width also conforms to a shape of the spider gears.
11. The differential of claim 8, wherein the thrust washer comprises a first portion and a second portion, wherein the first portion and the second portion are connected and configured to assemble around the spider and the spider gears.
12. The differential of claim 11, wherein the slope is configured to engage with the housing to reduce separation of the first portion and the second portion.
13. The differential of claim 11, wherein the first portion and the second portion are configured to provide a gap between the first portion and the second portion to allow the flow of debris or the like.
14. The differential of claim 8, wherein the thrust washer has a continuous ring shape.
Type: Application
Filed: Aug 16, 2022
Publication Date: Dec 8, 2022
Inventors: Benjamin BLACKMAN (Brantford), Shawn Thomas PETTE (Brantford), Peter HOSKIN (Brantford)
Application Number: 17/888,962