JPH05600Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention includes a sealed dust boot, more specifically, a cylinder and a rod that protrudes outward from within the cylinder and is supported by the cylinder in a reciprocating manner. This invention relates to a sealed dust boot that is used mainly in submerged parts that require complete waterproofness, such as in transmission control parts.

(Prior Art) In Figs. 4 and 5, which show a conventional sealed dust boot of this type applied to a transmission operating section, reference numeral 1 denotes a cylinder, and a rod 2 supported in the cylinder 1 for reciprocating motion protrudes outward from the cylinder 1. One end 5 of a dust boot 4 is attached to the peripheral edge 3 of the end of the cylinder 1, and the other end 6 of the dust boot 4 is attached to a prescribed location on the outer circumferential surface 7 of the rod. This attachment is firmly performed using a band 8 to maintain sealing performance. Reference numeral 9 denotes an expandable bellows portion which allows the dust boot 4 to expand and contract, and Fig. 4 shows the bellows portion as viewed from the left in Fig. 5 when compressed.
The figures show the respective states at the time of extension.

(Problem that the invention attempts to solve) However, in the above structure that maintains hermeticity,
The volume inside the dust boot 4 changes greatly as the dust boot 4 expands and contracts, and the volume inside the dust boot 4 decreases when compressed as shown in FIG.
will be subject to significant outward pressure. On the other hand, when the dust boot 4 is expanded as shown in FIG. 5, the volume inside the dust boot 4 increases, and as a result, the pressure inside the dust boot 4 decreases, and the dust boot 4 receives a large pressure from the outside. Therefore, there is a problem that the dust boot 4 is damaged early due to the action of these pressures, and there is also a problem that the dust boot 4 and the rod 2 interfere with each other, which adversely affects the operation of the rod 2. It was hot.

(Means for Solving the Problems) The present invention provides a transmission operation unit, etc. that includes a cylinder and a rod that protrudes outward in the axial direction from within the cylinder and is supported by the cylinder so as to be movable in a reciprocating manner.
A large-diameter cylindrical thick-walled part fixed to the end of the cylinder, a telescopic bellows part with a smaller diameter than the cylindrical thick-walled part fixed to the rod end and expandable and contractible in the axial direction, and a cylindrical thick-walled part. The volume absorbing part connects the elastic bellows part together, and the volume absorbing part extends from the large-diameter cylindrical thick-walled part toward the shaft core side, connects to the small-diameter elastic bellows part, and extends outward in the axial direction. This sealed dust boot is characterized by being formed into a thin wall that can protrude and recess freely in the axial direction.

(Embodiment) In FIGS. 1 to 3 showing an embodiment in which the present invention is applied to a transmission operating section, 1 is a cylinder, and a rod 2 supported by the cylinder 1 so as to be able to move back and forth is a cylinder. It protrudes outward from 1. One end 5 of the dust boot 4 is attached to the peripheral edge 3 of the cylinder 1, and the vicinity of the one end 5 forms a large-diameter cylindrical thick-walled part 11 that is thicker than other parts. The other end 6 of the cage dust boot 4 is attached to a predetermined location on the outer peripheral surface 7 of the rod. This installation requires band 8 to maintain a tight seal.
It is strongly implemented using Reference numeral 9 denotes a small-diameter telescopic bellows portion that makes the dust boot 4 expandable and retractable, and between the small-diameter telescopic bellows portion 9 and the large-diameter cylindrical thick-walled portion 11, a portion protrudes outward and inward. A thin volume absorbing portion 12, which can be recessed freely, is formed substantially perpendicular to the axial direction. The thick portion 11 has a thickness of, for example, approximately 5 mm, the volume absorbing portion 12 has a thickness of, for example, approximately 0.7 mm, and the other portions have a thickness of, for example, approximately 1 mm. Further, as the material of the dust boots 4, CR or EPDM, which is usually used for the dust boots 4, is adopted.

Next, the operation will be explained. In the free state where no force is acting on the dust boot 4, the volume absorbing portion 12 is flat as shown in FIG. In the contracted state shown in FIG. 2, the volume absorbing portion 12 protrudes outward to alleviate the volume reduction in the dust boot 4, and conversely, the rod 2 protrudes outward from the cylinder 1, causing the elastic bellows portion 9 to protrude outward. In the extended state shown in FIG. 3, the volume absorbing portion 12 is recessed inward to alleviate the increase in volume within the dust boot 4.

(Effect of the invention) The sealed dust boot 4 according to the invention has a large diameter cylindrical thick-walled part 1 fixed to the end of the cylinder 1.
1, an expandable bellows part 9 which has a smaller diameter and is fixed to the end of the rod and is expandable and retractable in the axial direction, and a thick cylindrical part 11.
and a volume absorbing part 12 that integrally connects the expandable and retractable bellows part 9, and the volume absorbing part 12 includes a large diameter cylindrical thick wall part 1.
The rod 2 is formed in a thin wall shape that extends from the rod 1 toward the shaft center and connects to the small-diameter expandable bellows portion 9, and can freely protrude outward in the axial direction and recess in the inward direction. When the inside of the dust boot 4 is about to be reduced by retracting into the cylinder 1, the volume absorbing portion 12 protrudes in the axial direction to prevent the change in volume.On the other hand, the rod 2 protrudes from the cylinder 1 and the dust boot 4 When the internal volume is about to increase, the volume absorbing portion 12 is recessed in the axial direction to prevent the volume from changing. Therefore dust boots 4
No large external pressure or internal pressure is applied to the dust boot 4, and problems such as early breakage of the dust boot 4 can be eliminated, and problems such as the interference of the rod 2 with the dust boot 4 can also be eliminated.

The volume absorption part 12 has two parts with different diameters,
That is, in order to connect the large-diameter cylindrical thick-walled part 11 and the small-diameter expandable bellows part 9, the shape is perpendicular to the axial direction or generally along it, so that the expandable bellows part 9
Unlike forming the volume absorbing portion 12 in the structure, the volume absorption can be easily increased, and the interference can be more effectively prevented.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, and Fig. 2 is a longitudinal side view showing the dust boot in a free state, Fig. 2 is a longitudinal side view showing the dust boot in the compressed state, and Fig. 3 shows the dust boot in the extended state. A vertical side view showing the state, FIG. 4 is a vertical side view showing the conventional example when compressed,
FIG. 5 is a longitudinal sectional side view showing the state of expansion. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Rod, 3... End periphery, 5... One end, 6... Other end, 12...
Volume absorber.

Claims (1)

[Scope of utility model registration request] A large-diameter cylindrical thick-walled part that is fixed to the end of the cylinder in a transmission operating section, etc. that includes a cylinder and a rod that protrudes outward in the axial direction from inside the cylinder and is supported in a reciprocating manner by the cylinder. , an expandable bellows part having a smaller diameter than the thick cylindrical part and fixed to the end of the rod and is expandable and contractible in the axial direction, and a volume absorbing part that integrally connects the thick cylindrical part and the expandable bellows part to absorb volume. The part is a thin-walled part that extends from a large-diameter thick cylindrical part toward the shaft center and connects to a small-diameter expandable bellows part, and can freely protrude outward in the axial direction and recess inward in the axial direction. A sealed dust boot characterized by being formed into.