DESC:Field of the invention

The present invention relates to a suspension system of an automobile, more particularly, the present invention 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

Shock absorbers such as hydraulic twin tube, mono tube, canister type shock absorber includes a piston rod at bottom portion thereof. In a conventional design, the shock absorber doesn’t have any cover over the piston rod which is exposed to open environment, as shown in figure 1a. When riding over mud and dusty road conditions, tire splashes mud and dust directly over the shock absorber, more specifically, on the piston rod. On continuous stroking, mud and dust particles accumulate around the piston rod region above the seals. These accumulated particles damage the outer diameter (OD) of the piston rod creating scratches and scoring marks which lead to oil leakage.

Apart from the piston rod, a bump stop also gets filled with mud and dust particles.
During shock absorber compression to full stroke, bump stop pushes and packs the mud and dust particles above the seals. This accumulated mud again damages the piston rod and sealing components.

Another shock absorber, as shown in figure 1b includes a dust tube over the piston rod. The dust seal is attached at an end of the dust tube which prevents the entry of dust and mud particles. However, this shock absorber requires more space to make a purposeful OD dust seal profile. Further, when the spring buckles, chances of the spring wire touching the OD of the seal and pushing it out prevails. Also, a single lip seal handles the entire mud thrown which makes the design critical. If any damage happens to seal lip, then entire mud enters, accumulates and pile up inside the dust tube.

In yet another shock absorber as shown in figure 1c, which involves two dust covers one over the other. The inner dust cover prevents direct splash of mud over the piston rod and the outer cover prevents entry of mud between the clearance of inner dust cover ID and damper OD. However, this shock absorber also requires more space between the spring ID (inner diameter) and damper OD in order to have two dust covers. Further, rubbing is bound to happen between two covers and effects of it could be noise and structural damage.

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 seal for a suspension system which prevents entry of mud and dust in a shock absorber, specifically at a piston rod.

Another object of the present invention is to provide a seal for the suspension system which requires less space.

Summary of the invention

Accordingly, the present invention provides a sealing assembly for preventing mud and dust accumulation in a shock absorber. The sealing assembly comprises a dust tube, a damper cap and a dust seal. The dust tube is adapted for covering a piston rod of the shock absorber. The dust tube includes a plurality of slots and a plurality of ribs configured thereon. The plurality of ribs is adapted to guide a spring of the shock absorber and to act as a locator for the spring.

The damper cap is fitted to a shock absorber body for covering a spinning area of a damper outer tube thereof. The damper cap is press fitted to the shock absorber body. The dust seal is stretched and mounted on the damper cap for covering the dust tube such that fluid entering therefrom into the dust tube gets drained out through the plurality of slots. The dust seal includes multiple lip profiles configured thereon for sealing the dust tube and preventing entry of mud particles and dust slurry therein. The multiple lip profiles comprise at least three primary lips and at least one auxiliary lip.

The dust tube while undergoing upward and downward movements as per the road undulations keeps the dust seal in close contact therewith thereby preventing any contaminant (dust) entry into the piston rod all through the stroke of the shock absorber.

Brief description of the drawings

The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein,
Figure 1a shows a conventional design of a shock absorber without a dust tube, in accordance with a prior art;

Figure 1b shows a dust tube design for the shock absorber with an OD seal, in accordance with another prior art;

Figure 1c shows a double dust tube for the shock absorber, in accordance with yet another prior art;

Figures 2a and 2b show a sealing assembly for preventing mud and dust accumulation in a shock absorber, in accordance with the present invention; and

Figures 3a, 3b, 3c and 3d show various components of the sealing assembly of figure 2a and 2b.

Detailed description of the invention

The foregoing objects of the 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 embodiment.

The present invention provides a sealing assembly for preventing mud and dust accumulation in a shock absorber. The sealing assembly requires less space and includes multiple lip profiles to provide effective sealing of a piston rod of the shock absorber.

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.

Referring now to figures 2a to 3d, there is shown a sealing assembly (70) for preventing mud and dust accumulation in a shock absorber (100), in accordance with the present invention. The shock absorber (100) includes a top mounting (10), a bottom mounting (20), a pressure cylinder (30), a piston rod (40) in communication with the pressure cylinder (30), a bump stop (50) for restricting the motion of the piston rod (40), a spring (60) covering the pressure cylinder (30) and the piston rod (40), and the sealing assembly (70) as shown in figure 2a. The sealing assembly (70) comprises a dust tube (72), a dust seal (74) and a damper cap (76) as shown in figure 2b.

The dust tube (72) (refer figure 3a) is adapted for covering the piston rod (40) of the shock absorber (100) from mud, dust and the like. The dust tube (72) is covered by the dust seal (74). The dust tube (72) includes a plurality of slots (72A) and a plurality of ribs (72B) configured thereon. The plurality of slots (72A) is adapted to drain out fluids such as water and other liquids entering through the dust seal (74). The plurality of ribs (72B) is adapted to guide the spring (70) and also acts as a locator for the spring (60).

The damper cap (76) (refer figure 3c) is fitted to a shock absorber body. The damper cap (76) is adapted for covering a spinning area (not numbered) of a damper outer tube (35) thereof. In an embodiment, the damper cap (76) is press fitted to the shock absorber body. However, it may be evident to those skilled in the art that the damper cap (76) is fitted to the damper body by other means known in the art.
The dust seal (74) for example a rubber seal is stretched and mounted on the damper cap (76) for covering the dust tube (72) for preventing entry of mud particles and dust slurry therein. The dust seal (74) covers the dust tube (72) such that fluid entering therefrom into the dust tube (72) gets drained out through the plurality of slots (72A).
The dust seal (74) includes multiple lip profiles configured thereon for effective sealing of the dust tube (72) and preventing entry of mud particles and dust slurry therein.

Specifically, the multiple lip profiles include at least three primary lips (74A) and at least one auxiliary lip (74B). The at least three primary lips (74A) and the at least one auxiliary lip/wiper (74B) are progressive lips means even if one of the at least three primary lips (74A) and the at least one auxiliary lip (74B) fails the rest remains functional to still provide multi stage protection to the dust tube (72)by preventing mud entry therein.

The damper tube, the dust seal (74) and the damper cap (76) are stationary in relation with the dust tube (72). The dust tube (72) moves up and down with respect to rest of the above parts as per the road undulations. This motion keeps the dust seal (74) to be in close contact with the dust tube (72) thereby preventing any contaminant (dust) entry in the piston rod (40) all through the stroke of the shock absorber (100).

Advantages of the invention

1. The sealing assembly (70) requires less space to design the seal between spring ID and damper OD.
2. The sealing assembly (70) provides effective sealing with the multiple lip profiles.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.
,CLAIMS:1. A sealing assembly (70) for preventing mud and dust accumulation in a shock absorber (100), the sealing assembly (70) comprising:
• a dust tube (72) covering a piston rod (40) of the shock absorber (100), the dust tube (72) having a plurality of slots (72A) and a plurality of ribs (72B) configured thereon, the plurality of ribs (72B) adapted to guide a spring (70) of the shock absorber (100) and to act as a locator for the spring (60);
• a damper cap (76) fitted to a shock absorber body for covering a spinning area of a damper outer tube (35) thereof; and
• a dust seal (74) stretched and mounted on the damper cap (76) for covering the dust tube (72) such that fluid entering therefrom into the dust tube (72) gets drained out through the plurality of slots (72A), the dust seal (74) having multiple lip profiles configured thereon for sealing the dust tube (72) and preventing entry of mud particles and dust slurry therein, the multiple lip profiles comprising at least three primary lips (74A) and at least one auxiliary lip (74B),
wherein, the dust tube (72) while undergoing upward and downward movements as per the road undulations keeps the dust seal (74) in close contact therewith thereby preventing any contaminant (dust) entry into the piston rod (40) all through the stroke of the shock absorber (100).

2. The sealing assembly (70) as claimed in claim1, wherein the damper cap (76) is press fitted to the shock absorber body.