DESC:MUD AND DUST RESISTANT SEALING ASSEMBLY IN SHOCK ABSORBER

Field of the invention:

The present invention generally relates to suspension system of an automobile, and more particularly it relates to a sealing assembly for preventing mud and dust accumulation in a shock absorber, specifically on and near a piston rod of the shock absorber.

Background of the invention:

Conventional vehicle suspensions like hydraulic twin tube and mono tube shock absorbers, canister type shock absorber etc. are not covered over the piston rod which is exposed to open environment.

The prior art is illustrated with reference to the accompanying figures 1A, 1B, 1C and 1D, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description and in the table below.

Ref. No. Component Ref. No. Component
5A Oil seal 10A Outer case
15A Piston rod 20A Spring
25A Case cap 30A Mud wiper seal
35A Gap between case cap and piston rod 40A Top mounting
45A Bump stop 50A Mud wiper assembly of prior art
100A Shock absorber

As shown in figures 1A, 1B, 1C and 1D, when riding over mud and dusty road conditions, tire splashes mud and dust directly over a shock absorber (100A), more specifically, on a piston rod (15A). A mud wiper assembly (50A) of the prior art includes a mud wiper seal (30A) fitted around the piston rod (15A), between the case cap (25A) and the oil seal (5A). Mud and dust particles get accumulated in the space between the bump stop (45) and the case cap (25) and during shock absorber compression to full stroke, the bump stop (45) pushes and packs the mud and dust particles in the gap (35A) between the case cap (25) and the piston rod (15A). This packed mud forms a thick layer in the gap (35A) and creates scratch marks on the piston rod (15A), which in turn damages the oil seal (5A) and the mud wiper seal (30A) and leads to oil leak.

Accordingly, there exist a need to provide a sealing mechanism for a piston rod of a shock absorber that overcomes the above mentioned drawbacks of the prior art.

Objects of the invention:

An object of the present invention is to provide a mud resistant seal for a shock absorber for preventing the entry of mud and dust accumulation therein.

Another object of the present invention is to provide a mud resistant seal for a shock absorber that will avoid formation of scratch marks due to dust and mud accumulation on piston rod.

Yet another object of the present invention is to provide a mud resistant seal for the shock absorber that will avoid oil leakage due to dust and mud entry into shock absorber.

Summary of the invention:

Accordingly, the present invention provides a mud and dust resistant sealing assembly for a shock absorber. The shock absorber includes a piston slidingly fitted in an outer case and having a piston rod extending through a case cap of the outer case and a bump stop for restricting the motion of the piston rod, and a spring covering the outer case and the piston rod. The mud and dust resistant sealing assembly comprises of a scraper ring fitted on the piston rod in such a way that it eliminates a gap by creating a sliding fit with the piston rod and interference fit with the case cap. The scraper ring swipes off the accumulated mud away from the case cap while oscillating thereby ensuring the shock absorber to free from mud packing and accumulation, and the piston rod to free from the formation of scratch marks thereon. This also avoids lip damage of the oil seal and oil leak problem. The scraper ring is made of any elastomeric material.

Brief description of the drawings:

The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein

Figure 1a shows a conventional design of a shock absorber without a sealing assembly, in assembly condition, in accordance with a prior art;

Figure 1b shows a conventional design of a shock absorber without a sealing assembly, in full stroke condition, in accordance with a prior art;

Figure 1c and 1d show an enlarged view of mud accumulation area of a conventional shock absorber without a sealing assembly, in accordance with a prior art;

Figure 2 shows a mud and dust resistant sealing assembly in a shock absorber, in accordance with the present invention; and

Figure 3 shows a mud and dust resistant scraper ring, in accordance with the present invention.

Detailed description of the embodiments:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides a mud and dust resistant sealing assembly in a shock absorber. The sealing assembly eliminates the possibility of mud accumulation and mud packing through a scraper ring made of elastomeric material. The scrapper ring eliminates the gap between the inner diameter of case cap and the outer diameter of piston rod by creating a sliding fit with piston rod and interference fit with the case cap. Also, the mud is swiped off from the case cap while oscillating. This ensures the damper to free from mud packing and accumulation which in turn eliminates the possibility of scratch formation and avoids the oil seal lip damage due to scratch marks, thereby avoiding the oil leak problem and improving the shock absorber life.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description and in the table below.

Ref. No. Component
5 Oil seal
15 Piston rod
25 Case cap
60 Scraper ring
70 Washer
80 Mud and dust resistant sealing assembly

Referring to Figures 2 to 3, a mud and dust resistant sealing assembly (80) (hereinafter referred as ‘the sealing assembly (80)’) in a shock absorber (not shown) in accordance with the present invention is shown.

The shock absorber is mounted between a top mounting (not shown) and a bottom mounting (not shown). The shock absorber includes a piston (not shown) slidingly fitted in an outer case (not shown) and having a piston rod (15) extending through a case cap (25) of the outer case and a bump stop (not shown) for restricting the motion of the piston rod (15), and a spring (not shown) covering the outer case and the piston rod (15). The sealing assembly (80) comprises of a scraper ring (60) fitted on piston rod (15) in such a way that it eliminates a gap (35A) by creating a sliding fit with the piston rod (15) and interference fit with the case cap (25). In an embodiment, the scraper ring (60) is made of any elastomeric material. The scraper ring (60) swipes off the accumulated mud away from the case cap (25) while oscillating thereby ensuring the shock absorber (100) to free from mud packing and accumulation, and the piston rod (15) free from the formation of scratch marks thereon. This also avoids lip damage of the oil seal (5) and oil leak problem.

Advantages of the invention:

1. Warranty reduction.
2. Avoids mud entry into a damper/shock absorber.
3. Life improvement.
4. Eliminate mud proofing parts like dust cover and dust cap.
5. Bump stop tearing due to case cap is eliminated.
6. Bump stop touch surface with a damper body is increased.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention. ,CLAIMS:We claim:

1. A mud and dust resistant sealing assembly (80) for a shock absorber, the shock absorber including a piston slidingly fitted in an outer case and having a piston rod (15) extending through a case cap (25) of the outer case and a bump stop for restricting the motion of the piston rod (15), and a spring covering the outer case and the piston rod (15), the mud and dust resistant sealing assembly (80) comprising:
a scraper ring (60) fitted on the piston rod (15) in such a way that it eliminates a gap (35A) between an inner diameter of a case cap (25) and an outer diameter of the piston rod (15) by creating a sliding fit with the piston rod (15) and an interference fit with the case cap (25);
wherein, the scraper ring (60) swipes off the accumulated mud away from the case cap (25) while oscillating thereby ensuring the shock absorber to free from mud packing and accumulation, and the piston rod (15) free from the formation of scratch marks thereon, thereby avoiding lip damage of an oil seal (5) and oil leak problem.

2. The mud and dust resistant sealing assembly (80) as claimed in claim 1, wherein the scraper ring (60) is made of any elastomeric material.

Dated this 14th day of August 2020

Madhavi Vajirakar
(Agent for Applicant)
IN/PA-2337