JPS6212939Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for sealing a magnetic fluid into a seal gap of a magnetic fluid seal that seals the outer periphery of a rotating shaft. Generally, a magnetic fluid seal has an annular magnet 2 loosely fitted around the outer periphery of a rotating shaft 1, as shown in FIG.
Annular magnetic pole pieces 3 and 4 are disposed at both ends of the magnetic poles, and the inner periphery of the magnetic pole pieces 3 and 4 and the shaft 1
A minute gap of about 0.1 to 0.3 mm is formed between the outer circumference of the magnetic fluid 5 and the magnetic flux path is injected with the magnetic fluid 5. Conventionally, as a means for injecting this magnetic fluid, the method shown in Fig. 1 is used. As shown in the figure, a micro cylinder 6 was used to inject from the seal gap of one pole piece 3 toward the seal gap of the other pole piece 4. However, in this method, the magnetic fluid only enters the seal gap of one of the magnetic pole pieces 3, and the remaining magnetic fluid usually flows to the outer peripheral surface of the shaft 1 and the upper surface of the magnetic pole piece 3, and the remaining magnetic fluid flows to the upper surface of the magnetic pole piece 3. It was difficult to allow the magnetic fluid to reach the seal gap between the pole pieces 4.

This device was devised to solve the above-mentioned conventional problems, and as shown in FIG. ', and cover member 1.
0 is fitted onto the shaft 1 via an O-ring 11, and is brought into close contact with the housing 6 of the rotary shaft device by bolting or using the palm of the hand to form a sealed space 13 inside the lid member 10. Further, the lid member 10 is provided with a pneumatic pipe 15 and a relief valve 16, and a minute pressure set by the relief valve 16 is sent into the sealed space from a pneumatic source (not shown). As a result, a predetermined amount of magnetic fluid 5' previously injected into the upper surface of the magnetic pole piece 3 is allowed to flow into the sealing gap formed between the two magnetic pole pieces 3 and 4, as indicated by reference numeral 5.

What is shown in FIG. 3 is another embodiment in which a lid member 20 is provided to completely cover the rotating shaft 1 when the protruding dimension of the tip of the rotating shaft 1 from the magnetic pole piece 3 is short. This is an illustration of an example. Components having the same functions as those in FIG. 2 are given the same reference numerals and have the same functions and effects, so please refer to the previous part for a detailed explanation.

The relief valve 16 used in this invention is preferably, for example, a relief valve for which the present applicant applied for a patent in November 1980.

Regarding the relief valve, please refer to the specification of the above-mentioned patent application for details, but to explain its general structure, as shown in FIG. 4, the tapered outer diameter 21 of the core rod 20 is sealed with a magnetic fluid seal 22. By moving the core rod 21 up and down, the sealing gap is adjusted, and thus the sealing pressure is adjusted to a predetermined pressure, and this pressure is used as a relief pressure, and the circuit pressure P is set to the above-mentioned predetermined sealing pressure. When the pressure is exceeded, the seal membrane of the magnetic fluid seal momentarily ruptures and the overpressure is released from the air relief hole 23, thereby reducing the circuit pressure P.
It is also possible to adjust the sensitivity with a sensitivity of 0.001Kgf/cm ² , and as mentioned above, the magnetic fluid injected into the upper surface of the magnetic pole piece 3 in advance can be applied to the seal gap between the two magnetic pole pieces 3 and 4 while maintaining the sealing state without blowing it away. It is possible to proceed without bias.

[Brief explanation of the drawing]

Fig. 1 shows an example of a conventional injection means, Fig. 2 shows an example of a conventional injection means;
The figure is a longitudinal cross-sectional view showing a state in which the injector of the present invention is attached and injects magnetic fluid, Fig. 3 is a longitudinal cross-sectional view showing another embodiment, and Fig. 4 is a relief to be used in the injector of the present invention. It is a sectional view showing an example of a valve. Explanation of symbols, 1...axis, 2...magnet, 3, 4...
... Magnetic pole piece, 5 ... Magnetic fluid, 10, 20 ... Lid member, 16 ... Relief valve, 20 ... Core rod,
22...Magnetic fluid seal, 23...Air relief hole.

Claims (1)

[Scope of utility model registration request] An annular magnet loosely fitted around the outer periphery of the rotating shaft, annular magnetic pole pieces disposed at both ends of the magnet, and magnetism held injected between the inner periphery of the magnetic pole piece and the outer periphery of the rotating shaft. A magnetic fluid injection device for transmitting a predetermined amount of magnetic fluid injected in advance into the inner peripheral portion of one magnetic pole piece of a magnetic fluid seal made of fluid from one magnetic pole piece to the other magnetic pole piece. comprising a lid-like member for forming a sealed space on the injection side end face of the one magnetic pole piece, and a pneumatic device piped to the lid-like member for increasing the internal pressure of the sealed space; A magnetic fluid injection device, wherein the pneumatic device includes a micro pressure relief valve.