This application claims the benefit of foreign application of TAIWAN Patent Application Serial Number 103122377, filed on Jun. 27, 2014, which are herein incorporated by reference in its integrity.
The invention is relevant to a bearing assembly, especially a sealed bearing assembly.
To allow the bearing assembly being operated safely and consistently under the required conditions, the bearing assembly requires sealing to prevent leakage of the lubricant within the assembly, and to prevent external dust, moisture, foreign substances, liquids, gases and other substances from entering into the bearing assembly. The assembly of elements for such purpose is the sealed bearing assembly.
With the advancement of technology, the sealed bearing assembly requirements are rising. However, the traditional bearing assembly can not maintain the sealing effect when the shaft moves with respect to the shell in a linear direction.
To sum up, the sealed bearing assembly, which can maintain the sealing when the shaft moves with respect to the shell in linear direction under stringent conditions, is required.
The invention aims to resolve the above-mentioned problems.
One embodiment of the invention provides a sealed bearing assembly including a shell; a shaft being movable linearly relative to the shell; a sealing ring fixed to the shaft, and the sealing ring is cylindrical, an axis of the sealing ring is identical to the axis of the shaft; an inner magnetic ring being provided in the sealing ring and being surrounding the shaft; an external magnetic ring being housed inside the shell and being surrounding the inner magnetic ring; and a ferrofluid being attracted by a magnetic force of the external magnetic ring to be distributed on a surface of the shell toward the shaft.
The ferrofluid is composed of magnetic particles, the surfactant molecules, and liquid carrier. Magnetic particles are nanoscale ferromagnetic molecules coated with surfactant molecules, and evenly dispersed in the liquid carrier, like a mass of flowing ferromagnetic material. When affected by magnetic field, the ferrofluid is distributed along the magnetic field lines and forms various shapes. To block a gap, the ferrofluid can be used together with the magnetic field to form the barrier to block both sides of the barrier.
The present invention uses the feature the ferrofluid can be attracted and moved by the magnetic force to achieve the sealing effect not only when the shaft rotates in a rotational direction but also when the shaft moves in a straight line.
Based on the experimental results, the sealed bearing assembly of the present invention is able to maintain a good sealing effect in the following conditions: 1*E-7 torr vacuum, 2 atm pressure difference, 0˜80° C. temperature range, 20 mm shaft diameter, 300 mm linear displacement stroke, 25 mm/sec linear displacement speed, and 200 RPM rotation speed.
The primitive objectives and advantages of the present invention will become apparent upon reading the following description and upon reference to the accompanying drawings in which:
In order to fully understand the manner in which the above-recited details and other advantages and objects according to the invention are obtained, a more detailed description of the invention will be rendered by reference to the best-contemplated mode and specific embodiments thereof. The following description of the invention is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense; it is intended to illustrate various embodiments of the invention. As such, the specific modifications discussed are not to be construed as limitations on the scope of the invention. It will be apparent to one skilled in the art that various equivalents, changes, and modifications may be made without departing from the scope of the invention, and it is understood that such equivalent embodiments are to be included herein. The terminology used in the description presented below is intended to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific embodiments of the invention. Certain terms may even be emphasized below; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this detailed description section. Where the context permits, singular or plural terms may also include the plural or singular term, respectively. Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of items in the list.
Preferred embodiments and aspects of the invention will be described to explain the scope, structures and procedures of the invention. In addition to the preferred embodiments of the specification, the present invention can be widely applied in other embodiments.
That is, when the shaft 102 in the linear movement direction 132 shown in
To sum up, based on the property that ferrofluid 302 can be attracted and moved by the magnetic force, the structure of the invention can achieve the sealing effect while the shaft 102 and the sealing ring 110 can not only rotate in the rotational movement direction 134 as shown in
Alternatively, the ring-shaped permanent magnets 112a-112e of the external magnetic ring 112 are arranged with same magnetic poles placed adjacently, as shown in
Alternatively, each two of the ring-shaped permanent magnets 112a-112e of the external magnetic ring 112 are separated by one of the permeable rings 118a-118d, which surround the inner magnetic ring 108, shown in
Alternatively, the external magnetic ring 112 can be a permanent magnet or an electrical magnet. That is, the external magnetic ring 112 may be an electromagnetic coil controlled by the current to produce the electromagnetic induction, and the magnetic force. Similarly, the inner magnetic ring 108 can be a permanent magnet or an electrical magnet. That is, the inner magnetic ring 108 may be an electromagnetic coil controlled by the current to produce the electromagnetic induction, and the magnetic force.
The foregoing description, for purposes of explanation, was set forth in specific details of the preferred embodiments to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practice the invention. Therefore, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description only and should not be construed in any way to limit the scope of the invention. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following Claims and their equivalents define the scope of the invention.
The above-described embodiments of the present invention are intended to be illustrative only. Numerous alternative embodiments may be devised by those skilled in the art without departing from the scope of the following claims.
Number | Date | Country | Kind |
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103122377 | Jun 2014 | TW | national |