Metal working – Means to assemble or disassemble – With control means energized in response to activator...
Reexamination Certificate
1999-02-22
2001-05-01
Hughes, S. Thomas (Department: 3726)
Metal working
Means to assemble or disassemble
With control means energized in response to activator...
C277S311000, C277S630000, C029S235000, C029S240000, C029S450000, C029S789000
Reexamination Certificate
active
06223424
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for sliding a seal with a lip, such as an oil seal or G seal, onto a shaft, a method for recovering the curl of the lip occurring when the seal is slid onto the shaft, and an apparatus for sliding the seal onto the shaft.
2. Description of the Related Art
Conventionally, a seal with a funnel-shaped lip is known. The lip projects toward the inner circumference of an annular body of the seal. In this seal, the end of the lip which is formed of an elastic member, such as rubber, is in direct contact with a shaft, so that the content (oil or ponder) inside the seal can be prevented from leaking outside and, at the same time, foreign objects (dust or the like) can be prevented from invading inside of the seal from the outside.
When the seal is slid onto the cylindrical shaft, which is a corresponding part to be incorporated with the seal, in a state in which the front end of the lip is directed toward the shaft, there is a case in which the lip is turned inward or is curled inside of the seal. This case makes it impossible to prevent the leakage of the content to the outside and prevent the invasion of the foreign objects through the seal.
For this reason, an apparatus has been proposed for sliding a seal with a lip onto a shaft without inverting or curling the lip in such a way that a pipe-like member is inserted in the seal in advance and, in this state, the seal is slid onto the shaft and there after the pipe-like member is pulled away from the seal (see Japanese Utility Model Application Early Laid-Open Publication No. Hei 4-76331, for example). Also, a seal with a lip has been proposed which is provided with a spring for pressing the seal so as not to curl the lip when sliding the seal onto a shaft (see Japanese Utility Model Application Early Laid-Open Publication No. Hei 6-30565, for example).
There is also a method for detecting whether a lip of a seal has been curled. For example, in Japanese Registered Utility Model No. 3007446, a method is proposed which includes the steps of forming a notch in the circumferential edge of a seal with a lip and making an air-leakage test in order to easily detect whether the lip of the seal has been curled.
In the aforementioned apparatus disclosed by Japanese Utility Model Application Early Laid-Open Publication No. Hei 4-76331, a mechanism for inserting the pipe-like member into the seal is also required in addition to a mechanism for sliding the seal onto the shaft. Therefore, disadvantageously, the apparatus requires a larger space, and an inserting operation must be carried out twice. As a result, the structure of the apparatus becomes complicated. In the aforementioned seal disclosed by Japanese Utility Model Application Early Laid-Open Publication No. Hei 6-30565, the seal is provided with an annular portion to which a garter sprint is attached to prevent the lip from curling. This makes the structure of the seal unique and complicated.
In the aforementioned method disclosed by Japanese Registered Utility Model No. 3007446, a device for supplying air is inevitably required to make the air-leakage test. As a result, large-sized assembly equipment is required, and thus equipment costs are raised.
Further, the prior art methods and apparatus mentioned above are each proposed from only the viewpoint of sliding the seal onto the shaft so that the lip is not turned inward or is not curled. In other words, the methods and apparatus pay no attention to uncurling the lip which has been curled.
SUMMARY OF THE INVENTION
It is a first object of this invention to provide a method for precisely sliding a seal onto a shaft without using a large apparatus space for the seal sliding, a peculiar structure of the seal, and an air-leaking test or the like, and an apparatus for sliding the seal by the seal-sliding method.
It is a second object of this invention to provide a method for easily returning a curled seal lip into the initial state in the case where a lip is curled when a seal is slid, and an apparatus for sliding the seal by the curled-seal-lip-returning method.
In order to achieve the first object, the seal-sliding method according to this invention comprises the step of sliding a seal while the shaft is rotated around the axial line of a shaft when the seal with a lip is slid onto the shaft (according to an aspect of this invention). Further, the apparatus for realizing the step of the seal-sliding method according to this invention, that is, the seal-sliding apparatus for sliding the seal with the lip onto the shaft, comprises a holding means for holding releasably the seal in the direction of the axial line of the shaft, and a shaft-rotating means for rotating the shaft, wherein the seal is slid onto the shaft while the shaft is rotated around the axial line by the shaft-rotating means (according to another aspect of this invention).
According to one of the two aspects mentioned above of this invention, since the shaft and the lip make friction in a rotational direction with each other when the shaft is rotated, the frictional resistance of the seal-sliding direction becomes lower, so that the lip can be prevented from being curled by the frictional force of the seal-sliding direction.
Further, in order to attain the first object, the seal-sliding method according to this invention comprises the step of sliding a seal while the seal is rotated around the axial line of a shaft when the seal with a lip is slid onto the shaft (according to another aspect of this invention). Further, the apparatus for realizing the step of the seal-sliding method according to this invention, that is, the seal-sliding apparatus for sliding the seal with the lip onto the shaft, comprises a holding means for holding releasably the seal in the direction of the axial line of the shaft, and a seal-rotating means for rotating the seal which is held by the holding means, wherein the seal is slid onto the shaft while the seal is rotated around the axial line of the shaft by the seal-rotating means (according to another aspect of this invention).
According to one of the two aspects mentioned above of this invention, since the shaft and the lip make friction in a rotational direction with each other when the seal is rotated, the same function as the function obtained when the shaft is rotated can be obtained. Further, the construction according to one of these two aspects is more effective in the case where the shaft cannot be rotated.
Further, in order to attain the first object, the seal-sliding method according to this invention comprises the step of sliding a seal while a shaft and the seal are rotated together around the axial line of the shaft when the seal with a lip is slid onto the shaft (according to another aspect of this invention). Further, the apparatus for realizing the step of the seal-sliding method according to this invention, that is, the seal-sliding apparatus for sliding the seal with the lip onto the shaft, comprises a holding means for holding releasably the seal in the direction of the axial line of the shaft, a seal-rotating means for rotating the seal which is held by the holding means, and a shaft-rotating means for rotating the shaft, wherein the seal is rotated by the seal-rotating means and the seal is slid onto the shaft while the shaft is rotated by the shaft-rotating means (according to another aspect of this invention).
According to one of the two aspects mentioned above of this invention, since the shaft and the lip make friction in a rotational direction with each other when the seal and the shaft are rotated. The same function as the function obtained when either the shaft or the seal is rotated can be obtained.
Further, in order to attain the first object, the seal-sliding method according to this invention comprises the steps of making a first operation in which a seal with a lip is at first slid onto a shaft, then making a second operation in which the seal is slid back to a position where the seal cannot be slid away from the shaft after th
Hiramatsu Motoi
Nakajima Mitsuru
Blount Steve
Hughes S. Thomas
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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