JPS6326610Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a mechanical seal related to the improvement of shaft sealing technology, and aims to provide a non-sliding type shaft sealing device for use in rear seals of engines, etc. It is.

[Conventional technology]

Conventionally, lip sliding type oil seals have been generally used as rear seals for engines, etc., and as shown in FIG. The shaft d is in sliding contact with the shaft d to prevent leakage of the sealed fluid when the shaft d rotates and stops.

[Problem that the invention attempts to solve]

However, the structure of the oil seal described above is such that seal member b is in close contact with both members a and d at all times regardless of whether the oil seal is in operation or stopped, and shaft d and lip part c slide during operation. However, there is a problem in that not only the sliding load is applied and the power consumption is increased, but also the sealing member and the mating member are worn out and the shaft sealing performance is short-lived.

This invention was made in view of the above problems,
The purpose of the present invention is to provide an energy-saving shaft sealing device that achieves a complete shaft sealing effect when stopped, forms a non-contact type shaft sealing device during operation, and eliminates the sliding load on the shaft sealing part. That is.

[Means for solving problems]

In order to achieve the above object, the present invention forms a thread on the truncated conical outer periphery of the tapered shaft hole formed in the shaft insertion part on the housing side, the inner side of which has a larger diameter.
and a threaded seal member with the inner end of the thread as a conical valve seat is externally mounted on the shaft so as to be slidable only in the axial direction, and is externally inserted on the shaft and adjacent to the inner end of the threaded seal, The inner end fixed to the shaft side and the sliding end that can be slid freely in the axial direction are connected via a spindle-shaped flexible cylindrical part with a stretchable annular weight having an appropriate load fixed to the mid-abdominal periphery. A screw seal balance mechanism is constituted by a rubber cylinder and an elastic member that elastically presses the inner end against the screw seal member, and the screw seal balance mechanism is configured to slide the screw seal in the axial direction by centrifugal force when the shaft rotates. It is configured as follows.

[Effect]

In the sealing device with the above configuration, when the shaft is stopped, the screw seal balance mechanism is stationary, so the sliding end of the rubber cylinder is pressed and moved in the direction of the screw seal by the elastic member, and comes into contact with the inner end of the screw seal. At the same time, the threaded seal is slid along the shaft in the direction of the small diameter of the tapered shaft hole.
Therefore, the conical valve seat formed at the inner end of the threaded seal comes into close contact with the tapered shaft hole and prevents the shaft sealing fluid from flowing out.

In addition, when the shaft rotates, the screw seal balance mechanism rotates together with the shaft, so the load of the heavy weight fixed to the periphery of the cylindrical part of the rubber cylinder is applied in the outer radial direction by centrifugal force. At the same time as the diameter of the middle part of the rubber cylinder expands, the sliding end slides in the direction of retreating from the screw seal against the pressure of the elastic member.

Therefore, the threaded seal slides on the shaft and moves in the direction of the larger diameter of the tapered shaft hole, creating a gap between the tapered shaft hole and the conical valve seat.However, the threaded seal is linked to the rotation of the shaft, and the outer periphery of the threaded seal A shaft sealing effect is exhibited by the screw sealing action caused by the relative movement between the thread and the tapered shaft hole, and a non-sliding shaft sealing device is constructed.

〔Example〕

Hereinafter, one embodiment of the shaft sealing device of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a front sectional view when the shaft 2 is stopped, and a truncated conical tapered shaft hole 1a with a larger diameter on the inside is formed in the shaft 2 insertion portion on the housing 1 side, and with respect to the shaft 2, At the inner end of the outer periphery of the threaded seal member 3, which is slidably inserted in the axial direction through the key 4 into the slide groove 3b formed in the axial direction of the shaft hole 3a, and is inserted airtightly through the O-ring 5. The formed conical valve seat 6 is inserted into the tapered shaft hole 1a and brought into close contact with the tapered shaft hole 1a.As shown in FIG. It is formed by continuously forming a tapered thread 7 whose diameter becomes slightly smaller. Reference numeral 8 denotes a screw seal balance mechanism that is arranged adjacent to the inside of the screw seal member 3 in the shaft 2, and is made of a flexible elastic material such as rubber. The slide ring 12 is fitted onto the outer periphery of the collar 11 which is fitted onto the shaft 2 and secured by the set screw 10, and the outer end side of the slide ring 12 is slidably fitted onto the shaft 2. The sliding end 9 is fitted and fixed to the outer periphery.
A heavy weight 13 is integrally disposed in the circumferential direction within the thickness of the midsection of the spindle cylindrical portion 9c, which forms the inner end portion 9a and the sliding end portion 9b. The above sliding end 9
b is a coil spring 14 elastically loaded between the inner edge 11a of the collar 11 and the inner edge 12a of the slide ring 12, so that the inner end surface 3c of the screw seal member 3 is
The threaded seal member 3 is pressed and slid in the direction of arrow A, and the conical valve seat 6 is inserted into the tapered shaft hole 1a.
They move in the direction of the smaller diameter and come into close contact with each other.

The shaft sealing device having the above configuration is used, for example, in the rear seal of an engine, with the screw seal balance mechanism 8 side installed on the engine side and the screw seal member 3 side installed on the gear side. When the shaft 2 rotates and enters the operating state, the screw seal balance mechanism 8 and the screw seal member 3 rotate together with the shaft 2, as shown in FIG. This rotation causes the spindle cylindrical portion 9 of the rubber tube 9 to
c A centrifugal force is generated against the heavy weight 13 installed in the middle of the mountain,
Since a force (arrow B) that increases the diameter of the midsection of the spindle cylindrical portion 9c is generated, the sliding end 9b of the rubber tube 9
moves in the direction of arrow C against the elasticity of the coil spring 14. Therefore, by the sliding end 9c, the screw seal member 3, which had been pressed in the direction of the small diameter of the tapered shaft hole 1a, moves in the slide groove 3b toward the large diameter side in the axial direction along the key 4, and the conical valve seat 6 is separated from the conical shaft hole 2a. However, the screw seal member 3 rotates together with the shaft 2,
Since there is relative rotation between the tapered shaft hole 1a and the tapered thread 7, the engine side and gear side are
A thread seal is achieved by the thread action of the tapered thread 7, forming a non-sliding type shaft sealing device.

Furthermore, when the above operation is stopped and the rotation of the shaft 2 stops, the centrifugal force (arrow B) applied to the heavy weight 13 of the screw seal balance mechanism 8 disappears.
Due to the elastic return of the coil spring 14, the screw seal member 3 is again slid in the direction of arrow A via the slide ring 12, and the conical valve seat 6 comes into close contact with the tapered shaft hole 1a, ensuring a sealed state when stopped. Become.

[Effect of idea]

As described above, the shaft seal device of the present invention constitutes a non-sliding type shaft seal device using the screw seal when rotating, and when stopped, the valve seat that is integrated with the screw seal is used as a non-rotating part. Since the shaft seal structure is in close contact with each other, the sliding load during operation is eliminated, creating a shaft sealing device with low operating consumption.It also provides a reliable shaft sealing effect when stopped. Since the seal part does not slide, there is little wear on the seal part and the initial sealing performance can be maintained for a long period of time.The practical effects of the present invention are extremely large.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing one embodiment of the shaft sealing device of the present invention in a stopped state, Fig. 2 is a front view of the same threaded seal member, and Fig. 3 is a front sectional view showing an operating state in Fig. 1; FIG. 4 is a half-cut sectional view showing a conventional oil seal. 1...Housing, 1a...Tapered shaft hole, 2...
... Shaft, 3 ... Thread seal member, 6 ... Conical valve seat, 7 ... Tapered thread, 8 ... Thread seal balance mechanism, 9 ... Rubber tube, 11 ... Collar,
12...Slide ring, 13...Heavyweight, 14...
…coil spring.

Claims (1)

[Scope of utility model registration request] For the tapered shaft hole formed in the shaft insertion part on the housing side, where one side has a large diameter, the shaft inserted through the tapered shaft hole is prevented from rotating, and is inserted freely in the axial direction, while at the same time A threaded seal member that constitutes a conical valve seat is inserted into the large diameter end of the formed tapered thread so as to be freely releasable and detachable, and is inserted adjacently to the large diameter side of the threaded seal member with respect to the shaft to form the threaded seal. The sliding end that comes into contact with the shaft and the fixed end that is fixed to the shaft side are connected by a telescopic cylindrical part, and a heavy weight is arranged around the middle of the cylindrical part, and the sliding end is screwed and sealed. A screw seal balance mechanism is formed by elastically pressing an end face of the member, and when the shaft rotates, centrifugal force applied to the screw seal balance mechanism maintains the screw seal member and the tapered shaft hole in a non-sliding state. Characteristic shaft sealing device.