Spring devices – Resilient shock or vibration absorber – Nonmetallic – resilient element
Reexamination Certificate
1999-12-08
2001-07-10
Butler, Douglas C. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Nonmetallic, resilient element
C267S140130, C267S219000
Reexamination Certificate
active
06257562
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a liquid filled vibration isolating device mainly used for supporting a vibration generating body such as an engine of an automobile.
The liquid filled vibration isolating device supports a vibration generating body such as an engine of an automobile while preventing the transmission of the vibration of the vibration generating body to a vehicle body or the like. It is known a type of liquid filled vibration isolating device which is constructed such that; a partitioner is provided for dividing a liquid chamber in a vibration isolating device body into a main liquid chamber and a sub liquid chamber; and an orifice which communicates the main liquid chamber with the sub liquid chamber is formed in the partitioner; and the vibration attenuating function is achieved by the effect of flowing of liquid in the liquid chambers through the orifice. Furthermore, recently, a double-orifice-type of liquid filled vibration isolating device is. known which has two orifices in the partitioner for attenuating the vibrations of different frequencies has been known.
For example, JP-A-09100866 (Japanese Patent Publication, unexamined, 9-100866(1997)), hereinafter referred to Prior art 1, proposes a vibration isolating device where an upper side of first partition member on a main liquid-chamber-side is covered with second partition member which adheres a sub diaphragm thereto by vulcanization, so as to define a third liquid chamber in an inner portion of the partition members; and a second orifice is formed to communicate with the third liquid chamber; whereby one orifice passage is for preventing low-frequency shake vibrations while another orifice passage in for preventing high-frequency idle vibration.
Furthermore, JP-A-09210117 (Japanese Patent Publication, unexamined, 9-210117(1997)), herein after referred to Prior art 2, proposes a vibration isolating device where a sheet of elastic member which is formed by vulcanization is clamped between a partition member and a restricting member defining a sealed air chamber, thus constituting two diaphragms of different modulus of elasticity from a sheet of elastic member; and between the partition member and these diaphragms, a liquid chamber which is communicated with an orifice formed in an outer peripheral portion of the partition member and a second liquid chamber which is communicated with a second orifice formed in an inner portion of the partition member are defined so that the vibration isolating device can cope with the vibration of wide frequency band such as the shake vibration and the idle vibration.
In such double-orifice liquid filled vibration isolating devices, particularly, the length and the cross sectional area of the orifice formed in the partitioner, and furthermore, the modulus of elasticity of both diaphragms become important parameters for achieving a given vibration attenuating function. The durability and the sealing ability to maintain this vibration attenuating function also become important. Furthermore, the easiness of assembling the partitioner to a vibration isolating device body must be taken into account.
From this viewpoint, the inventors have reviewed the reliability,.the easiness of mounting (shape and size of caulking portions), the functionality, and the easiness of assembling of products of the Prior arts 1 and 2. With respect to the Prior art 1, the vibration isolating device is constructed such that the lower partitioner member is fitted into the bowl-shaped upper partitioner member which opens downwardly; and orifices defined by these upper and lower partitioner members are respectively formed in the outer-peripheral side and the inner side of the lower partitioner member. Accordingly, there arises a problem with respect to the maintenance of the sealing ability of the orifices. Furthermore, the high accuracy of dimension of the upper and lower partitioner members is required.
On the other hand, with respect to the Prior art 2, two diaphragms which differ in the modulus of elasticity are formed of one elastic member so that, at the time of assembling, it is necessary to pay an attention to the shape of the caulking portion so as to prevent the dimensional variation or dimensional tolerance between the elastic member and the partition member from becoming large and hence, the caulking operation becomes difficult. Furthermore, in case the dimensional variation or dimensional tolerance becomes large, it gives an adverse effect to the cross sectional area of the orifices and the modulus of elasticity of the diaphragms thus living rise to problems which affects the functionality of the equipment.
BRIEF SUMMARY OF THE INVENTION
In view of the above, the inventors have vigorously made a research on a vibration isolating device, particularly on the structure of a partitioner thereof which can meet the reliability, the functionality, the easiness of mounting and the easiness of assembling of products, and have found that by adopting following constitution: a partitioner has basically a three member construction which consists of an upper partitioner member, a lower partitioner member and an elastic member; and the lower partitioner member has an outer peripheral portion thereof extended outwardly in a radial direction; and only such an extended portion is fixedly secured to a mounting metal fitting of a vibration isolating device body by caulking; and the upper side partitioning member has an upper-end outer peripheral portion, thereof pressed onto a liquid-chamber-side outer peripheral end portion of a vibration isolating base body. At the time of assembling the partitioner, by only pushing the upper partitioner member into the body along a thin film portion of the body until the upper partitioner member comes into contact with an outer peripheral portion of the vibration isolating base body in the condition that the body is held in a liquid vessel in an up-side-down posture, and subsequently placing the lower partitioner member on the upper partitioner member from above and fixedly securing the extended portion of the lower partitioner member to the mounting metal fitting by caulking, the reliability, the functionality and the easiness of mounting of the products can be assured and the products can be easily assembled.
In case a first orifice groove of a U-shaped cross section which has a peripheral side face portion opened is formed in the upper partitioner member and the upper partitioner member is pushed into the equipment body along the thin film portion of the equipment body, a first orifice can be readily formed at a space portion surrounded by the first orifice groove and the thin film portion and furthermore, the first orifice can have a desired cross sectional area.
Such an upper partitioner member may be obtained by subjecting a sheet of metal plate material to drawing or the like so as to form an orifice groove formed in an outer peripheral portion thereof. However, in view of obtaining a desired cross sectional area and shape, an integrally molded product is preferable. The upper partition member may be formed of either metal (aluminum, for example) or synthetic resin.
When the lower partitioner member is a flat-plate like member which closes the second orifice groove opened downwardly at the inner side of the upper partitioner member from downside is, following advantages is achieved: the assembling is facilitated; and an additional or separate step for press-fitting the partition member; and a special tool for expelling entrained residual air becomes unnecessary. Furthermore, since the partitioner is constructed such that it is pressed toward the vibration isolating base body by fixedly securing the lower partitioner member by caulking, the reliability of the product is assured even when the vibration isolating base body is deteriorated as time elapses.
In case the first orifice is made thin and long while the second orifice is made thick and short, the level difference or stepped portion may give arise between the lower surfaces of the first an
Hashimoto Tsutomu
Takashima Yukio
Butler Douglas C.
Jordan and Hamburg LLP
Kramer Devon
Toyo Tire & Rubber Co., Ltd.
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