JPH0451090Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rack-and-pinion power steering device mainly used in automobiles.

A rack-and-pinion power steering device is known as a device that uses hydraulic power to assist steering wheel operations.

Generally, a gear housing includes a rack that connects to a wheel operating arm, and a pinion that meshes with the rack and rotates together with the steering handle.

For example, as shown in FIG.
The bearing portion supports a steering shaft 2 which is interlocked with a steering handle (not shown), with a bearing 3 and an oil seal 4 interposed therebetween, so that the steering shaft 2 can rotate freely and seal the oil in the housing 1.
Furthermore, a dust cover 5 is attached to the end of the bearing portion of the housing 1 from which the shaft 2 projects, to prevent muddy water and the like from entering the bearing portion.

This dust cover 5 has its large diameter portion 5A fitted into a spigot portion 6 formed in the housing 1, and its small diameter portion 5B fitted into an annular groove 7 formed in the shaft 2.
It can be installed by fitting it.

One problem with the dust cover 5 is that the spigot part 6 needs to be machined on the housing 1 side. ), the size of the dust cover 5 increases.

On the other hand, in the case shown in FIG.
3A in contact with the port 12A of the control valve 12 to prevent interference with the port 12A of the control valve 12. However, in this case, even if the outer diameter of the dust cover 13 could be reduced, there was a drawback in that good sealing performance could not be obtained.

The present invention has been developed by focusing on these problems, and in the bearing part of the steering shaft of a rack-and-pinion gear housing, the outer diameter part that fits into the gear housing and the main lip and dust lip that come into sliding contact with the steering shaft. An oil seal is formed having a connecting portion connecting the outer diameter portion and both lips, and the oil seal has an annular core member on the outer diameter portion thereof and a separate member from the annular core member at the connecting portion. An annular reinforcing member is provided, respectively. Further, a part of the reinforcing member is provided with a pilot part into which the large diameter part of the dust cover is slidably fitted, and an annular groove into which the small diameter part of the dust cover is tightly fitted is formed in the steering shaft. Then, a sealed space is defined by the steering shaft, oil seal, and dust cover, and grease is sealed in the space.

This minimizes the outer diameter of the dust cover. In addition, the oil seal follows each part regardless of misalignment caused by wear or dimensional errors between the gear housing and steering shaft, and the grease sealed in the sealed space inside the dust cover provides reliable dustproof performance. .

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the same components as in the conventional example are denoted by the same reference numerals.

As shown in FIG. 3, the oil seal 15 has an outer diameter portion 16 that fits into the gear housing 11, a main lip 17 that slides against the steering shaft 2 and seals the inside of the housing 11, and an outer diameter portion 17 that seals the inside of the housing 11 outside the main lip 17. A dust lip 18 that slides into contact with the outside to isolate it from the outside, and a connecting part 1 that connects the outer diameter part 16, the main lip 17, and the dust lip 18.
9, and is molded from rubber or the like with an annular cross-section. An annular garter spring 20 is attached to the outer periphery of the main lip 17, and a metal ring 21 as an annular core member having an L-shaped cross section is provided on the outer diameter portion 16. When the oil seal 15 is inserted into the gear housing 11, the stopper rib 21A of the metal ring 21 abuts against the end face of the housing to position the oil seal 15.

Now, in the present invention, a metal reinforcing ring 22 as an annular reinforcing member having an L-shaped cross section is formed by press working, and this reinforcing ring 22 is attached to the oil seal 15.
It is adhered to the side surface of the connecting portion 19 by baking. The flange portion 2 rises from the reinforcing ring 22 in the axial direction.
3 is a spigot part into which the dust cover 24 is fitted.

As shown in FIG. 4, the oil seal 15 provided with the pilot part 23 is attached to the power steering type gear housing 11. Then, the large diameter part 25 of the dust cover 24 is fitted into the spigot part 23, and the small diameter part 26 is fitted into the annular groove 7 formed in the shaft 2. In addition, oil seal 1
5, the dust cover 24, and the shaft 2 are filled with grease.

According to the above configuration, the dust cover 24 covers the sliding contact portion of the oil seal 15 with the shaft 2, prevents muddy water, etc. from directly splashing onto the sliding portion from the outside, and prevents foreign matter from biting into the dust lip 18 and preventing the lip portion from getting into contact with the oil seal 15. and shaft 2 are worn, oil seal 15
prevent the sealing function from deteriorating.

On the other hand, the dust cover 24 tightly fitted into the annular ring 7 of the steering shaft 2 rotates as the steering shaft 2 rotates, and its large diameter portion 25 slides against the reinforcing ring 22 (spigot part 23) of the oil seal 15. Provides dustproof function by contacting the At this time, the metal ring 21 that holds the oil seal 15 on the gear housing 11 side and the reinforcing ring 22 are constructed separately, and are subject to a slight relative movement in the radial direction due to the deformation of the connecting portion 19. Even if the steering shaft 2 and gear housing 11 become misaligned due to wear, for example, or if the dust cover 24 is eccentric to the steering shaft 2 due to dimensional errors during manufacturing, these can be fixed. The sliding contact state between the dust cover 24 and the reinforcing ring 22 is reliably maintained by compensating for the misalignment of the dust cover 24 and the reinforcing ring 22, thereby providing an excellent dustproof mechanism.

Furthermore, even if foreign matter such as dust enters the inner space of the dust cover 24, this foreign matter will be blocked by the grease sealed in the space and the oil seal 15 will be blocked.
It is difficult for the dust to reach the part of the dust strip 18, and even if it does, wear or damage to the dust strip 18 can be kept to a minimum due to the lubricating action of the grease. Therefore, good sealing performance can be exhibited for a long period of time.

In another embodiment shown in FIG. 5, a reinforcing ring 30 having a U-shaped cross section is bonded to the oil seal 15. The dust cover 31 is formed into an F-shaped cross section and is engaged with the reinforcing ring 30.

According to the above configuration, the engagement portion between the reinforcing ring 30 and the dust cover 31 becomes double, and the sealing performance can be further improved.

As described above, the present invention provides an annular reinforcing member separate from the annular core member that holds the oil seal in the gear housing, and allows the dust cover that is tightly fitted to the steering shaft to slide into contact with this reinforcing member. In addition, since the grease is sealed in the sealed space defined inside the dust cover, the dust cover can be made smaller and the sealing performance and durability of the oil seal can be sufficiently ensured. Furthermore, since it is not necessary to cut the spigot part on the gear housing side, it is also possible to reduce production costs.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional example. FIG. 2 is a sectional view of another conventional example. FIG. 3 is a sectional view of an oil seal showing an embodiment of the present invention, and FIG. 4 is a sectional view of a bearing portion. FIG. 5 is a sectional view of an oil seal and a dust cover of another embodiment. 2... Steering shaft, 11... Gear housing, 15... Oil seal, 22, 30...
...Reinforcement ring, 24, 31...Dust cover.

Claims (1)

[Scope of utility model registration request] In the bearing portion of the steering shaft of a rack-and-pinion gear housing, an oil seal has an outer diameter portion that fits into the gear housing, a main lip and a dust lip that slide in contact with the steering shaft, and a connecting portion that connects the outer diameter portion and both lips. The oil seal is provided with an annular core member on its outer diameter portion, an annular reinforcing member separate from the annular core member at the connecting portion, and a part of the reinforcing member is provided with a dust cover. The steering shaft is provided with a spigot portion into which the large diameter portion of the dust cover is slidably fitted, and an annular groove into which the small diameter portion of the dust cover is tightly fitted,
A sealing device for a rack-and-pinion gear housing, characterized in that a steering shaft, an oil seal, and a dust cover define a sealed space, and the space is filled with grease.