[001] The present subject matter described herein, relates to a rack and pinion
structure for a vehicle and, in particular, to a pinion housing structure, a pinion
cover, and a dust cover for sealing and to restrict entry of water and dust particles.
BACKGROUND AND PRIOR ART:
[002] In general, a pinion is mounted in a rack and pinion housing structure. The
10 rack portion of the housing is a cylindrical structure having a neck portion which
is a cylindrical structure at an angle to receive the pinion input shaft along with
pinion cover and pinion adjusting screw.
[003] Generally, the pinion cover has a plurality of slots that receive a device or
a tool to assemble the pinion cover in the neck portion of pinion housing structure.
15 The plurality of slots is provided for holding the pinion cover during assembly
and tightening of pinion cover in the pinion housing. Further, the pinion cover is
covered by a dust cover to restrict entry of water and dust particles in the
assembly of the pinion input shaft with rack shaft. A rubber oil seal is provided in
between the pinion cover and the pinion input shaft to restrict entry of the water
20 and dust particles.
[004] During underbody washing, water jet is used which gets inside the dust
cover and oil seal area. This water gets accumulated in the slots of pinion cover
and slowly causes rusting near the oil seal and pinion junction. The rusted pinion
slowly erodes the oil seal creating gap through which the accumulated water gets
25 inside the rack and pinion housing.
[005] Despite having dust cover and rubber sealing, water enters the pinion
housing from lower direction of the pinion input shaft. The existing structures of
the pinion housing and dust covers are not efficient enough to restrict entry of
water and dust particles from all directions.
3
[006] With the existing structure of pinion housing and the dust cover, water and
dust particles enter the assembly of pinion shaft and rack shaft which decreases
the smoothness of steering action and creates noise.
[007] Another technical problem associated with the existing structures is that it
5 reduces lifetime of the rack and pinion assembly.
[008] Therefore, there is a need in the art to provide a pinion housing structure
that can restrict entry of water and dust particles.
OBJECTS OF THE INVENTION:
[009] Some of the objects of the present disclosure, which at least one
10 embodiment herein satisfy, are listed herein below.
[0010] The principal object of the present invention is to provide a pinion housing
having a rib structure to restrict entry of water with dust particles.
[0011] Another object of the present subject matter is to provide a dust cover with
a protrusion with optimized shape and height to restrict entry of water jet with
15 dust particles.
[0012] Another object of the present subject matter is to provide a pinion cover
with optimized sloped profile towards pinion housing to allow exit of entrapped
water through sloped profile.
[0013] Another object of the present subject matter is to provide a pinion cover
20 with a plurality of protrusions.
[0014] Yet another object of the present subject matter is to provide a pinion
cover with a pathway in between two consecutive protrusions from the plurality of
protrusions.
[0015] Yet another object of the present subject matter is to provide a pinion
25 cover with the plurality of protrusions defining a shape for engagement with a tool
for assembly and dis-assembly.
[0016] These and other objects and advantages will become more apparent when
reference is made to the following description and accompanying drawings.
4
SUMMARY OF THE INVENTION:
[0017] This summary is provided to introduce concepts related to pinion housing
of rack and pinion assembly in vehicle. The concepts are further described below
in the detailed description. This summary is not intended to identify key features
5 or essential features of the claimed subject matter, nor is it intended to be used to
limit the scope of the claimed subject matter.
[0018] In an embodiment, the present disclosure relates to a rack and pinion
housing structure including a pinion housing, a pinion input shaft and a pinion
cover. The pinion input shaft is fitted in the pinion housing together with the
10 pinion cover. Further, an oil seal is provided in between the pinion input shaft and
the pinion cover. The pinion housing has a rib structure that is diametrically
extending from circumference of the pinion housing in between a lower end and a
top end. The pinion cover defines a plurality of protrusions, symmetrically,
extending away from an upper surface of the pinion cover. The pinion cover
15 defines an inclined pathway in between two consecutive protrusions for passage
of entrapped water. The inclined pathway eliminates the accumulation of water
with dust particles as it is sloped away from the inclined surface of the pinion
cover. Once the pinion cover and the oil seal are placed, a dust cover is provided
over the pinion housing to cover the pinion cover and the oil seal to restrict entry
20 of water with dust particles in the pinion housing.
[0019] In another embodiment, the present subject matter relates to a dust cover
that can be provided over the pinion housing to restrict entry of water with dust
particles. The dust cover includes a tapered disc portion and a vertical wall portion
that bends from the tapered disc portion defining a U shaped cross section.
25 Further, the tapered disc portion defines a central hole along central axis (XX’).
Further, the disc portion has a continuous circular protrusion concentric with the
central axis (XX’). The continuous circular protrusion extends from the tapered
disc portion in extended direction of the vertical wall portion. The continuous
circular protrusion is provided in between the central hole and the vertical wall
30 portion.
5
[0020] To further understand the characteristics and technical contents of the
present subject matter, a description relating thereto will be made with reference
to the accompanying drawings. However, the drawings are illustrative only but
not used to limit scope of the present subject matter.
5 BRIEF DESCRIPTION OF THE DRAWINGS
[0021] It is to be noted, however, that the appended drawings illustrate only
typical embodiments of the present subject matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally
effective embodiments. The detailed description is described with reference to the
10 accompanying figures. In the figures, the left-most digit(s) of a reference number
identifies the figure in which the reference number first appears. The same
numbers are used throughout the figures to reference like features and
components. Some embodiments of system or methods in accordance with
embodiments of the present subject matter are now described, by way of example,
15 and with reference to the accompanying figures, in which:
[0022] Fig. 1 illustrates general rack and pinion housing structure;
[0023] Fig. 2 and 3 illustrate structure of pinion housing with pinion cover, in
accordance with existing art;
[0024] Fig. 4a illustrates un-assembly view of dust cover, pinion cover and pinion
20 housing, in accordance with an embodiment of the present subject matter;
[0025] Fig. 4b and 4c illustrate assembled view of the pinion cover and the pinion
housing, in accordance with an embodiment of the present subject matter;
[0026] Fig. 5a, 5b, and 5c illustrate perspective, side, and top view of the pinion
cover, respectively, in accordance with an embodiment of the present subject
25 matter;
[0027] Fig. 6a, 6b, and 6c illustrates perspective top, perspective bottom and cross
section different view of the dust cover, respectively, in accordance with an
embodiment of the present subject matter;
6
[0028] Fig. 7 illustrates cross section view of pinion housing structure with input
shaft, pinion cover, rubber seal, and dust cover, in accordance with an
embodiment of the present subject matter.
[0029] The figures depict embodiments of the present subject matter for the
5 purposes of illustration only. A person skilled in the art will easily recognize from
the following description that alternative embodiments of the structures and
methods illustrated herein may be employed without departing from the principles
of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
10 [0030] The detailed description of various exemplary embodiments of the
disclosure is described herein with reference to the accompanying drawings. It
should be noted that the embodiments are described herein in such details as to
clearly communicate the disclosure. However, the amount of details provided
herein is not intended to limit the anticipated variations of embodiments; on the
15 contrary, the intention is to cover all modifications, equivalents, and alternatives
falling within the scope of the present disclosure as defined by the appended
claims.
[0031] It is also to be understood that various arrangements may be devised that,
although not explicitly described or shown herein, embody the principles of the
20 present disclosure. Moreover, all statements herein reciting principles, aspects,
and embodiments of the present disclosure, as well as specific examples, are
intended to encompass equivalents thereof.
[0032] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of example embodiments. As
25 used herein, the singular forms “a”,” “an” and “the” are intended to include the
plural forms as well, unless the context clearly indicates otherwise. It will be
further understood that the tennis “comprises,” “comprising,” “includes” and/or
“including,” when used herein, specify the presence of stated features, integers,
steps, operations, elements and/or components, but do not preclude the presence
7
or addition of one or more other features, integers, steps, operations, elements,
components and/or groups thereof.
[0033] It should also be noted that in some alternative implementations, the
functions/acts noted may occur out of the order noted in the figures. For example,
5 two figures shown in succession may, in fact, be executed concurrently or may
sometimes be executed in the reverse order, depending upon the functionality/acts
involved.
[0034] Unless otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by one of
10 ordinary skill in the art to which example embodiments belong. It will be further
understood that terms, e.g., those defined in commonly used dictionaries, should
be interpreted as having a meaning that is consistent with their meaning in the
context of the relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
15 [0035] These and other advantages of the present subject matter would be
described in greater detail with reference to the following figures. It should be
noted that the description merely illustrates the principles of the present subject
matter. It will thus be appreciated that those skilled in the art will be able to devise
various arrangements that, although not explicitly described herein, embody the
20 principles of the present subject matter and are included within its scope.
[0036] Referring to fig. 1 that illustrates rack and pinion housing structure. The
rack housing and pinion housing are hollow cylindrical structures. The pinion
housing is connected with the rack housing at an angle. The pinion housing
defines like a neck portion to the rack housing. From the pinion housing, the
25 pinion input shaft passes and meshes with rack of the rack housing for steering
operations. In order to avoid entry of water jet with dust particles, a dust cover is
provided to cover the pinion housing.
[0037] Figures 2 and 3 illustrate rack and pinion housing structure with existing
pinion cover. The rack and pinion housing structure includes a pinion housing
8
400, a pinion input shaft 200, and a pinion cover 100. The pinion housing 400 is a
cylindrical hollow structure configured to receive the pinion input shaft 200 and
the pinion cover 100. The pinion input shaft 200 is fitted in the pinion housing400
together with the pinion cover 100. Further, an oil seal 500 is provided in between
5 the pinion input shaft 200 and the pinion cover 100 in the pinion housing 400.
[0038] As shown in the figure 3, the pinion cover 100 has a plurality of cavities or
slots 101. The plurality of cavities 101 provides assistance for holding the pinion
cover 100 with a torque device (not shown in figures) for tightening the pinion
cover 100 with the pinion housing 400. Further, each cavity from the plurality of
10 cavities 101 is separated by a solid portion which define a flat surface.
[0039] In this structure, water gets entrapped in these cavities which causes
corrosion in pinion near oil seal area resulting in entry of water with dust particles
in the assembly of rack and pinion shafts. One solution is provided in the parent
application 201911004736 where these cavities are covered by a rubber plug.
15 [0040] To solve the above mentioned problem, the present subject matter provides
a pinion cover 300 and a dust cover 700 that overcomes the above mentioned
technical problem.
[0041] As shown in the figure 4a that illustrates un-assembled view of the dust
cover 700, the pinion cover 300, and the pinion housing 400. The pinion cover
20 300 is assembled with the pinion housing 400; and dust cover 700 is placed over
the pinion housing 400.
[0042] As shown in figs. 4b and 4c that illustrate assembled view of the pinion
cover 300 and the pinion housing 400. The pinion housing 400 defines a rib
structure 401 that is diametrically extending from outer circumference of the
25 pinion housing 400. The rib structure 401 is provided in form of circular flange
that expand from the outer circumference of the cylindrical pinion housing 400.
The rib structure 401 is provided in between a lower end 400b and a top end 400a
of the pinion housing 400. As shown in the figure 7, diameter ‘D’ of the rib
structure 401 is greater than diameter ‘d’ of the pinion housing 400. Further, as
9
shown in figure 7, width ‘W’ of the rib structure 401 can be optimized with
respect to width of the dust cover to restrict entry of water jet with dust particles
from downward direction.
[0043] Referring figs. 5a, 5b, and 5c that illustrate structure of the pinion cover
5 300 in accordance with an embodiment of the present subject matter. The pinion
cover 300 defines a cylindrical structure having top end 300a and a bottom end
300b. The pinion cover 300 has a through hole 303 at a central axis (XX’) in order
to receive the pinion input shaft 200. The pinion cover 300 has a plurality of
protrusions 301 that are extending symmetrically upward around circumference of
10 the through hole 303 from upper surface 300c of the top end 300a of the pinion
cover 300. The plurality of protrusions 301 combinedly define a polygonal shape
that can be selected from but not limited to triangular, rectangular, pentagonal,
hexagonal, heptagonal, octagonal, nonagonal, decagonal. Although, the present
subject matter is explained by illustrating hexagonal shape, the shape can be any
15 polygonal shape with features as described here. The plurality of protrusions 301
combinedly define a shape that can be engaged with corresponding tool for
assembly and dis-assembly. In an aspect, the plurality of protrusions (301)
combinedly define a shape corresponding to holding profile of a tool. A pathway
302 is provisioned in between two consecutive protrusions 301 from the plurality
20 of protrusions 301. In an embodiment, a pathway 302 is provided on each side of
the defined shape to allow passage of trapped water.
[0044] The plurality of protrusions 301 provide assistance for holding the pinion
cover 300 with a torque device (not shown in figures) for tightening the pinion
cover 300 within the pinion housing 400. In another embodiment, each protrusion
25 from the plurality of protrusions 301 is separated by a pathway 302 to allow
passage of water that gets entrapped. The pathway 302 of the pinion cover 300
defines a sloped profile that slops down towards top end 400a of the pinion
housing 400. Further, the upper surface 300c of the pinion cover 300 defines a
sloped profile that slops down towards top end 400a of the pinion housing 400.
10
[0045] In an embodiment, shape of the protrusions can be any shape, such as
pentagon, rectangular, triangular that combinedly define a shape corresponding to
holding profile of a tool. In an embodiment, the plurality of protrusions is
integrated with the pinion cover 300. In another embodiment, the plurality of
5 protrusions is joined with the pinion cover 300 by means of known joined
methods, such as arc welding.
[0046] Fig. 6a illustrates perspective view of top surface of the dust cover 700,
fig. 6b illustrates perspective view of bottom surface of the dust cover 700, and
fig. 6c illustrates cross section view of the dust cover 700. The dust cover 700
10 defines a tapered disc portion 701 and a vertical wall portion 702. The vertical
wall portion 702 bends from the tapered disc portion 701. The dust cover 700 with
the tapered disc portion 701 and the vertical wall portion 702 define a U shaped
cross section profile as shown in fig. 6c. Further, a central hole 704 is provided at
center of the tapered disc portion 701. The central hole 704 is defined at central
15 axis (XX’) (as shown in fig. 6c) of the tapered disc portion 701 to receive the
pinion input shaft 200.
[0047] Referring to figs. 6b, the tapered disc portion 701 has a first continuous
circular protrusion 701a that extend from the tapered disc portion 701 in
extending direction of the vertical wall portion 702. Further, height of the first
20 continuous circular protrusion 701a is less than height of the vertical wall portion
702. The first continuous circular protrusion 701a rests on top end 400a of pinion
housing 400. The first continuous circular protrusion 701a is provided at radial
distance from the central hole 704. The continuous circular protrusion 701a is
provided closer to the vertical wall portion 702.
25 [0048] As shown in the figure 3, the pinion input shaft 200 has a circular groove
201 to receive the dust cover 700. Referring fig. 7, in the circular groove 201, the
central hole 704 of the dust cover 700 is fitted to cover the oil seal 500 and to
avoid entry of water jet with dust particles inside the pinion housing 400 through
the central hole 704.
11
[0049] Figure 7 illustrates cross section view of assembled dust cover 700, pinion
cover 300, pinion input shaft 200, and oil seal 500. The circular groove 201
(shown in figure 3) defines a diameter 201a that is less than diameter 200b of the
pinion input shaft 200. Further, diameter 704a of the central hole 704 of the dust
5 cover 700 is lesser than the diameter 201a of the circular groove 201 to ensure
interference fit between the circular groove 201 and the dust cover 700.
[0050] Referring to figure 7, a second continuous circular protrusion 704b
extended peripherally from the central hole 704 in direction of the vertical wall
portion 702 is provided for mating with pinion input shaft 200 and the oil seal
10 500. The diameter 704c of the continuous circular protrusion 704b is more than
diameter 704a of the central hole 704 but less than diameter 201a of the pinion
input shaft circular groove 201. The continuous circular protrusion 704b rests over
the oil seal 500 to avoid entry of water and dust particles. Further, the oil seal 500
is moved in upward direction to match with level of top surface of the pinion
15 cover 300 and have a contact with the continuous circular protrusion 704b of the
dust cover 700.
[0051] In an aspect, internal diameter 700b of the dust cover 700 is more than
diameter ‘d’ of the pinion housing 400 and less than diameter ‘D’ of the rib
structure 401. Further, width 700a of the vertical wall portion 702 is less than
20 extending portion width ‘W’ of the rib structure 401. Accordingly, the rib
structure 401 covers the vertical wall portion 702 completely to restrict entry of
water jet with dust particles from downward direction.
[0052] In the assembly, the dust cover 700 is mounted in the circular groove 201
of the input shaft 200. Further, the dust cover 700 defines a gap ‘G’ in between
25 the rib structure 401 and vertical wall portion 702 to allow exit of entrapped water
which may get inside despite obstruction provided by the rib structure 401. The
gap ‘G’ act as a channel to allow passage of water that got entrapped via any
means near the oil seal 500.
12
[0053] As shown in the assembly, the first continuous circular protrusion 701a
rests on top end 400a of the pinion housing 400 to restrict any water and dust
particles entry into the oil seal area.
[0054] However, due to continuous rubbing of the first continuous circular
5 protrusion 701a with the pinion housing 400 while operating vehicle steering
system, the first continuous circular protrusion 701a may get worn out. As a
result, a gap is formed between the first continuous circular protrusion 701a and
top end 400a of the pinion housing 400 and some water may enter in the pinion
housing 400 in between the pinion shaft 200 and the pinion cover 300 or in
10 between the oil seal 500 and the dust cover 700. However, the entrapped water
passes outside the vehicle through the slopped pathway 302 and the gap ‘G’
provided between the rib structure 401 and vertical wall portion 702 of the dust
cover 700 and does not get accumulated in the pinion housing 400. By such
means, the present subject matter provides a better and efficient sealing structure
15 for the pinion housing to restrict entry and accumulation of water jet with dust
particles and also removal of entrapped water, if any, through the slopped
pathway 302 and the gap ‘G’.
[0055] It will be understood by those within the art that, in general, terms used
herein, and especially in the appended claims (e.g., bodies of the appended
20 claims) are generally intended as “open” terms (e.g., the term “including” should
be interpreted as “including but not limited to,” the term “having” should be
interpreted as “having at least,” the term “includes” should be interpreted as
“includes but is not limited to,” etc.). It will be further understood by those within
the art that if a specific number of an introduced claim recitation is intended, such
25 an intent will be explicitly recited in the claim, and in the absence of such
recitation no such intent is present. For example, as an aid to understanding, the
following appended claims may contain usage of the introductory phrases “at least
one” and “one or more” to introduce claim recitations. However, the use of such
phrases should not be construed to imply that the introduction of a claim recitation
30 by the indefinite articles “a” or “an” limits any particular claim containing such
13
introduced claim recitation to inventions containing only one such recitation, even
when the same claim includes the introductory phrases “one or more” or “at least
one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should
typically be interpreted to mean “at least one” or “one or more”); the same holds
5 true for the use of definite articles used to introduce claim recitations. In addition,
even if a specific number of an introduced claim recitation is explicitly recited,
those skilled in the art will recognize that such recitation should typically be
interpreted to mean at least the recited number (e.g., the bare recitation of “two
recitations,” without other modifiers, typically means at least two recitations, or
10 two or more recitations). Furthermore, in those instances where a convention
analogous to “at least one of A, B, and C, etc.” is used, in general such a
construction is intended in the sense one having skill in the art would understand
the convention (e.g., “a system having at least one of A, B, and C” would include
but not be limited to systems that have A alone, B alone, C alone, A and B
15 together, A and C together, B and C together, and/or A, B, and C together, etc.).
In those instances where a convention analogous to “at least one of A, B, or C,
etc.” is used, in general such a construction is intended in the sense one having
skill in the art would understand the convention (e.g., “a system having at least
one of A, B, or C” would include but not be limited to systems that have A alone,
20 B alone, C alone, A and B together, A and C together, B and C together, and/or A,
B, and C together, etc.). It will be further understood by those within the art that
virtually any disjunctive word and/or phrase presenting two or more alternative
terms, whether in the description, claims, or drawings, should be understood to
contemplate the possibilities of including one of the terms, either of the terms, or
25 both terms. For example, the phrase “A or B” will be understood to include the
possibilities of “A” or “B” or “A and B.”
[0056] While the foregoing describes various embodiments of the invention, other
and further embodiments of the invention may be devised without departing from
the basic scope thereof. The scope of the invention is determined by the claims
30 that follow. The invention is not limited to the described embodiments, versions
or examples, which are included to enable a person having ordinary skill in the art
14
to make and use the invention when combined with information and knowledge
available to the person having ordinary skill in the art.

We claim:

1. A rack and pinion housing structure (800) comprising:
a pinion housing (400); and
a pinion input shaft (200) fitted in the pinion housing (400)
5 together with a pinion cover (300),
characterized in that
the pinion cover (300) defines a through hole (303) at central axis
(XX’) to receive the pinion input shaft (200) and a plurality of protrusions
(301) extending outward from upper surface (300c) of the pinion cover
10 (300) around circumference of the through hole (303).
2. The rack and pinion housing structure (800) as claimed in claim 1, wherein
a rib structure (401) is diametrically extending from the pinion housing (400) in
between a top end (400a) and a lower end (400b) of the pinion housing (400).
3. The rack and pinion housing structure (800) as claimed in claim 1, wherein
15 the rack and pinion housing structure (800) further comprise a dust cover (700)
provided over the pinion housing (400).
4. The rack and pinion housing structure (800) as claimed in claim 1, wherein
a pathway (302) is provided in between two consecutive protrusions from the
plurality of protrusions (301).
20 5. The rack and pinion housing structure (800) as claimed in claim 1, wherein
the plurality of protrusions (301) combinedly define a polygonal shape.
6. The rack and pinion housing structure (800) as claimed in claim 1, wherein
the pinion cover (300) is sloped down towards the top end (400a) of the pinion
housing (400).
25 7. The rack and pinion housing structure (800) as claimed in claim 3, wherein
the dust cover (700) comprises:
a tapered disc portion (701) and a vertical wall portion (702) that
bent from the tapered disc portion (701);
a central hole (704) defined at central axis (XX’) of the tapered
30 disc portion (701);
16
a first continuous circular protrusion (701a) extended from the
tapered disc portion (701) in extending direction of the vertical wall
portion (702), the first continuous circular protrusion (701a) is defined in
between the central hole (704) and the vertical wall portion (702).
5 8. The rack and pinion housing structure (800) as claimed in claim 2, wherein
a gap (G) is defined in between the rib structure (401) and vertical wall portion
(702) of the dust cover (700).
9. A pinion cover (300) comprises:
a cylindrical structure having a top end (300a) and a bottom end
10 (300b); and
a through hole (303) extending from the top end (300a) to the bottom
end (300b) at central axis (XX’) of the cylindrical structure,
characterized in that
a plurality of protrusions (301) extending outward from upper surface
15 (300c) of the top end (300a) around circumference of the through hole
(303); and
a pathway (302) provided in between two consecutive protrusions
from the plurality of protrusions (301), wherein the pinion cover (300) is
sloped down towards top end (400a) of a pinion housing (400).
20
10. The pinion cover (300) as claimed in claim 9, wherein the plurality of
protrusions (300) combinedly define a polygonal shape.