JPH0744859Y2 - Vertical shaft seal - Google Patents

Description

[Detailed Description of the Invention] <Industrial application field> The present invention relates to a seal for fitting the vertical groove portion of a vertical grooved shaft such as a spline shaft or a serration shaft to seal the inner portion of the shaft. .

<Prior art> One of the technologies for connecting and detaching a shaft by attaching a rotation stopper to the shaft is to provide a vertical groove such as a spline groove or a serration groove on the outer peripheral surface of one shaft, and a hole for the other shaft. There is a method in which a vertical groove having the same shape as that of the vertical groove is provided on the inner peripheral surface of and the both are fitted and coupled. For example, such a technique is employed for coupling the tip of a steering shaft and the tip of an input shaft of a gear housing in a power steering device of an automobile.

FIG. 6 shows a part of a gear housing in such a power steering device. An input shaft 2 is arranged in the gear housing 1. This input shaft 2
Of the tip portion protruding from the upper part of the gear housing 1,
Serration 3 is formed. A valve mechanism 4 for hydraulic control is formed in an intermediate portion of the input shaft 2, and a pinion (not shown) is provided below the valve mechanism 4 and meshes with a rack gear that drives left and right wheels.

An oil seal 5 and a dust cover 6 are fitted and attached to the input shaft 2 on the upper portion of the gear housing 1 in order to prevent dust and rainwater from entering the gear housing 1. The oil seal 5 is attached inside the gear housing 1, and the dust cover 6 is attached outside the gear housing 1.

The above power steering device and the gear housing thereof are well known, and the operation thereof is performed as follows. That is, when the steering wheel of the automobile is rotated, the input shaft 2 rotates accordingly, and the dust cover 6 and the valve mechanism 4 rotate integrally with the input shaft 2. The rotation is transmitted to a pinion (not shown), and the rotation of the pinion is converted into a reciprocating motion of a rack shaft having a rack gear meshing with the pinion, thereby driving the left and right wheels. The valve mechanism 4 is operated by a hydraulic mechanism (not shown) to generate hydraulic pressure that assists the force for driving the left and right wheels. It should be noted that the housing 1 is maintained in a stationary state without rotating. The material of the dust cover 6 is rubber or synthetic resin.

When the dust cover 6 is attached to the lower portion of the serration 3 of the input shaft 2 as shown in the figure, if the fitting hole 7 of the dust cover 6 is simply circular, it goes without saying that the trough portion of the serration 3 and the dust cover Since a gap is formed between the cover 6 and 6, the sealing function as a dust cover is lost.
For this reason, conventionally, the fitting hole 7 of the dust cover 6 is preliminarily provided with a lip having the same shape as the serration 3, or the fitting hole 7 is provided with a circular lip, and the dust cover 6 is forcibly press-fitted to the same as the serration 3. I was forming a lip. Also, the seal at the cerebration part is given up and the inner cylindrical part is sealed.

<Problems to be Solved by the Invention> However, a method of previously forming a lip having the same shape as the serration 3 in the fitting hole 7 of the dust cover 6 is a metal for forming a lip without a gap between the serration 3 and the lid 3. There is a problem that the die structure becomes complicated and the finishing method becomes complicated, resulting in high cost.

Further, the method of forming a circular lip in the circular fitting hole 7 of the dust cover 6 and forcibly pressing the dust cover 6 to form the shape following the serration 3 requires a very large crushing allowance and insertion force. There is a problem to do.

Further, in the method of sealing with the inner cylindrical portion of the serration 3, since sealing at the portion of the serration 3 is not performed at all, rainwater or the like may invade from the serration portion to cause rust or adversely affect the sealing function. There is a problem.

Therefore, an object of the present invention is to provide a vertical grooved shaft seal capable of reliably sealing a vertical groove portion such as a serration by a simple mounting method.

<Means for Solving the Problems> The vertical grooved shaft seal according to the present invention has a circular lip integrally formed on the periphery of the fitting hole of the seal and having a diameter smaller than the diameter of the trough of the vertical groove of the shaft. The circular lip is a thin circular lip that breaks into a shape following the vertical groove when the vertical groove portion of the shaft is inserted into the fitting hole.

<Operation> When a seal provided with a thin circular lip is press-fitted into a shaft having a vertical groove, the thin circular lip is broken along with the end face shape of the vertical groove, so that the serration can be closed successfully. Since the lip is thin, the insertion pressure is small.

<Embodiment> FIG. 1 shows an embodiment of the present invention. This embodiment is also configured as a dust cover attached to the input shaft of the power steering device similar to that described above. The tip of the input shaft 12 projects from the upper part of the gear housing 11, and a serration 13 is formed there. An oil seal 14 is attached to the inside of the upper portion of the gear housing 11 between the oil housing 14 and the input shaft 12, and a dust cover 15 is fitted from below to the lower portion of the serration 13 of the input shaft 12. The material of the dust cover 15 is the sixth
This is similar to that of the dust cover 6 in the related art shown in the figure.

The dust cover 15, as shown in FIGS. 2 and 3,
Disc part 17 with flange 16 on the periphery and fitting hole in the center
And a boss portion 19 having 18. Insertion direction A of fitting hole 18
A circular thin lip 20 is formed on the periphery of the end portion on the opposite side to. The inner diameter D1 of the fitting hole 18 is substantially equal to the outer diameter D2 of the serration 13 of the input shaft 12, and the inner diameter D3 of the rip 20 is smaller than the root diameter D4 of the serration 13. Therefore, when the fitting hole 18 of the dust cover 15 is press-fitted from the tip of the input shaft 12, the serrated shape of the end face of the serration 13 ruptures the thin-walled circular lip 20 to follow the serrated shape to form a seal lip. As shown in FIG. 4, the valley portion of the serration 13 is well closed. At this time, the inner diameter D3 of the lip 20
Is smaller than the root diameter D4 of the serration 13
As shown in FIG. 1, presses the valley portion of the serration 13 in a just-turned-up shape to ensure the seal. Moreover, since the insertion force is sufficient to break the thin-walled lip 20, a small force is sufficient.

In the above embodiment, the inner diameter portion of the fitting hole 18 is simply circular, but as shown in FIG. 5, the inner diameter portion of the fitting hole 18 may be a serration groove 21 that coincides with the serration 13.

Each of the above embodiments is an example in which the present invention is realized as a dust cover attached to the input shaft of a power steering device, but it goes without saying that the present invention can be applied to other devices and is not limited to a serration or a spline. The present invention can be applied to a fluted shaft seal having the shape or structure described above.

<Effect of device> As described above, the vertical grooved shaft seal according to the present invention is
It has a smaller diameter than the trough diameter of the vertical groove of the shaft with vertical groove on the periphery of the fitting hole of the seal, and when the vertical groove portion of the shaft is inserted into the fitting hole, it will break into a shape that follows the vertical groove. Since a thick circular lip, that is, a thin circular lip is provided, it is possible to form a seal lip in the shape of a vertical groove of the shaft by simply fitting the fitting hole of this seal to the shaft with a relatively small force. ,
It is possible to achieve a seal that is easy to install and has a reliable sealing effect.

[Brief description of drawings]

FIG. 1 is a schematic partial sectional view of an apparatus provided with a shaft seal having vertical grooves showing an embodiment of the present invention, FIG. 2 is a plan view of the seal, and FIG. 3 is III of FIG. -A cross-sectional view taken along line III, Fig. 4 is a plan view showing a fitted state of a seal and a shaft in the same embodiment, and Fig. 5 is a partial plan view of a seal showing another embodiment of the present invention. FIG. 6 is a partial cross-sectional view of a gear housing portion of a power steering device for an automobile showing a conventional example. 11 ... Gear housing, 12 ... Input shaft (corresponding to the vertical grooved shaft of the present invention), 13 ... Serration (corresponding to the vertical groove of the present invention),
14 ... Oil seal, 15 ... Dust cover (corresponding to the seal of the present invention), 20 ... Thin circular lip, D3 ... Inner diameter of thin circular lip, D4 ... Valley diameter of serration.

Claims (1)

[Scope of utility model registration request] 1. A seal having a fitting hole fitted into the shaft for hermetically sealing the flute of the shaft, the trough of the shaft having a trough at the periphery of the fitting hole. A circular lip having a diameter smaller than the diameter of the portion is integrally provided, and when the circular lip of the shaft is inserted into the fitting hole, the circular lip breaks into a shape that follows the vertical groove. A shaft seal with a vertical groove, characterized by a thin circular lip.