JPS6028843Y2 - oil seal - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an oil seal, and more specifically, it provides an oil seal structure that has pressure resistance and facilitates insertion of a shaft.

In oil seals used in equipment where the sealed fluid is at high pressure, the seal lip that makes sliding contact with the shaft surface receives fluid pressure and comes into excessive pressure against the shaft circumferential surface, causing trouble due to friction. Therefore, measures are required to ensure pressure resistance.

In conventional oil seals, the seal lip that slides sealingly against the shaft circumferential surface is often thickened to provide rigidity. It is necessary to take a small
As a result, the ability to follow the eccentricity of the shaft is extremely low.
The problem of easy leakage cannot be avoided.

In view of the above-mentioned problems with the conventional oil seal, the present invention has developed an annular shape with an inner diameter slightly larger than the shaft diameter by using a low-friction synthetic resin material in the waist portion adjacent to the seal lip of the oil seal. A backup ring made in the body is inserted to support the seal lip that receives fluid pressure so that it can withstand pressure, and the diameter of the backup ring is small (compared to the inner diameter of the seal member), and By cutting it at one place and creating a structure that can be expanded outward when combined with the sealing member,
This is intended to avoid difficulties in assembling the shaft due to the rigidity of the low-friction synthetic resin material.

Hereinafter, embodiments of the oil seal according to the present invention will be described based on the drawings.

In the embodiment shown in FIG. 1, the sealing member 1 has a sealing lip portion 2 that sealingly slides on the curved surface of the shaft 10, a waist portion 3 that connects to the sealing lip portion 2, and a mounting cylindrical portion 4 that is fitted into the housing 11. , the inner peripheral surface of the waist portion 3 having a substantially truncated conical shape is made of a low-friction synthetic resin material, and the shaft 10
A backup ring 7 having an inner diameter slightly larger than the outer diameter of the seal member 1 and the backup ring 7 is fitted, and the end faces of the seal member 1 and the backup ring 7 are supported by a stopper 12 attached to the end face of the housing 11.

An annular projection 5 is provided on the inner side of the end of the seal member 1, and has the function of preventing the backup ring 7 from separating from the seal member 1 during handling, assembly, etc.

The backup ring 7 has an outer diameter smaller than the inner diameter of the seal member 1 in its free state, and is further provided with a cut 8 at one location on its circumference, as shown in FIG. .

When inserting the backup ring 7 into the sealing member 1, as shown in FIG. 3, by shifting the backup ring 7 at the cut portion 8, the diameter of the backup ring 7 is made smaller than that of the annular protrusion 5, so that it can be easily inserted. Ru.

The above-mentioned insertion operation can be facilitated by making the cutting portion 8 inclined with respect to the radial direction.

When inserting the shaft 10 having an annular groove or the like at the tip into the oil seal according to the present invention which is a combination of the seal member 1 and the backup ring 7, as shown in FIG. In order to prevent the lip portion 2 and the backup ring 7 from being damaged by the shaft 10, the shaft 10 is covered with a cylindrical protective cover 14.
At that time, the seal lip portion 2 expands outward due to its own elasticity, and the backup ring 7 is provided with a cutting portion 8 and a slight gap is provided between it and the seal member 1. It expands outward to allow passage of a protective cover 14 having a larger diameter than the shaft 10.

Since the oil seal according to the present invention has the above-described structural requirements, the following effects are brought about.

The sealing member 1 protects the inner peripheral surface of the waist portion 3 from the backup ring 7.
The backup ring 7 is supported on the circumferential surface of the shaft 10, and the backup ring 7 is supported on the circumferential surface of the shaft 10.
is made of a low-friction material, the seal lip portion 2 is prevented from coming into excessive contact with the circumferential surface of the shaft 10 even if the fluid to be sealed is under high pressure. , the friction troubles seen in the above are avoided, and furthermore, since the backup ring 7 is manufactured with a gap maintained between it and the inner circumferential surface of the seal member 1 and is provided with the cut portion 8, the seal member 1 It is possible to expand outward in the fitted state, so when inserting the shaft 10,
This prevents damage to the seal lip portion 2 or the backup ring 7 during insertion.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the oil seal according to the present invention installed on the shaft and housing, Figure 2 is a cross-sectional view showing the same state before installation, and Figures 3 and 3 are when the seal member and backup ring are assembled. FIG. 4 is a sectional view showing the situation when the shaft is inserted into the oil seal. DESCRIPTION OF SYMBOLS 1... Seal member, 2... Seal lip part, 3... Waist part, 4... Mounting cylindrical part, 5... Annular projection , 7... Backup ring, 8... Cutting section, 1°... Shaft, 11 Housing, 12... Stopper, 14・・・・・・Protective cover

Claims (1)

[Scope of utility model registration request] A seal member 1 comprising a seal lip portion 2 and a waist portion 3 adjacent to the seal lip portion 2, and a backup ring 7 made of a low-friction material and fitted into the waist portion 3.
An oil seal characterized in that the backup ring 7 is cut at one place of the annular body and is expandable outward when fitted with the seal member 1.