JP2021038826A - Boot - Google Patents

Abstract

To suppress the deformation of a film part caused by a pressing force of grease while suppressing the lowering of the following performance of the film part with respect to the movement of an application object.SOLUTION: A boot 1 comprises a pair of annular attachment parts 10, 20, and a film part 30 extending between a pair of the attachment parts 10, 20. The film part 30 has an inner face 31 being a portion having flexibility, and being a face facing a joint, and an outer face 32 being a face back-facing the inner face 31, and a plurality of ribs 33. The ribs 33 are portions formed at least at either of the inner face 31 and the outer face 32, and protruding from the face. The plurality of ribs 33 form at least two annular rows 34, and the plurality of ribs 33 are aligned with intervals in the rows 34. In a pair of the adjacent rows 34, the plurality of ribs 33 in one of a pair of the rows 34, and the plurality of ribs 33 in the other of a pair of the rows are formed while being displaced from each other in a peripheral direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to boots, and more particularly to boots used in joints.

Joints that join two members such as universal joints used for automobile propeller shafts are made of boots to prevent foreign matter such as muddy water and dust from entering from the outside and to prevent the outflow of grease inside. It is covered and housed inside the boots. When the joint rotates at high speed, the grease applied to the joint may be radially blown off by centrifugal force, and the grease blown off from the joint hits the film part of the boot and pushes the film part. Due to the pressing force of the grease on the film portion, the film portion is deformed to the outer peripheral side, and this deformation may damage the film portion. For this reason, conventionally, a boot structure that can suppress the deformation of the film portion even when the pressing force of grease is applied has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 7-224857

On the other hand, boots are required to follow the movement of the shaft in order to seal the space covering the joint. The conventional structure for suppressing the deformation of the film portion due to the pressing force of the grease as described above is a structure that makes the film portion less likely to be deformed, and is a structure that seeks an action contrary to the followability of the film portion. For this reason, conventionally, there has been a demand for a boot structure capable of suppressing deformation of the film portion due to pressing force of grease while maintaining the followability of the film portion.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to suppress deformation of the film portion due to pressing force of grease while suppressing reduction of followability of the film portion to the movement of an application target. The purpose is to provide boots that can be planned.

In order to achieve the above object, the boot according to the present invention is a boot used for a joint that joins two members so as to be movable relative to each other, and is between a pair of annular mounting portions and the pair of mounting portions. The film portion has an inner surface which is a surface facing the joint, an outer surface which is a surface facing the inner surface, and a plurality of ribs. It is a portion provided on at least one of the inner surface and the outer surface and projects from the surface, and the plurality of ribs form at least two annular rows, and in each of the rows, the plurality of ribs. The ribs are arranged at intervals in the circumferential direction, and in the pair of adjacent rows, the plurality of ribs in one of the pair of rows and the plurality of ribs in the other of the pair of rows are arranged in the circumferential direction. It is characterized in that it is formed so as to be offset from each other.

In the boot according to one aspect of the present invention, in the adjacent pair of rows, the rib in one of the pair of rows is aligned with the portion of the other of the pair of rows in which the rib is not formed. They are arranged so that they overlap in the direction.

In the boot according to one aspect of the present invention, in the adjacent pair of rows, the plurality of ribs in one of the pair of rows includes a portion of the other of the pair of rows in which the plurality of ribs are not formed. They are arranged so that they overlap each other in the direction in which the rows are lined up.

In the boot according to one aspect of the present invention, in each of the rows, the plurality of ribs are arranged at equal intervals in the circumferential direction.

In the boot according to one aspect of the present invention, the spacing between the pair of adjacent rows is not the same.

According to the boot according to the present invention, it is possible to suppress the deformation of the film portion due to the pressing force of the grease while suppressing the reduction of the followability of the film portion to the movement of the object to be applied.

It is sectional drawing of the sealing device in the cross section along the axis for showing the schematic structure of the sealing device which concerns on embodiment of this invention. It is a perspective view of the boot shown in FIG. It is a figure which shows typically the positional relationship of the rib in a pair of rows which are adjacent to each other of a plurality of rows. It is a figure for showing the boot in the use state attached to the propeller shaft of the automobile which is an example of an application object, and is the sectional view along the axis which shows the vicinity of the universal joint of a propeller shaft enlarged. It is a figure which shows the deformation example of a rib, FIG. 5A is a figure which shows one deformation example of a rib, and FIG. 5B is a figure which shows the other deformation example of a rib.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view taken along the axis x for showing a schematic configuration of the boot 1 according to the embodiment of the present invention, and FIG. 2 is a perspective view of the boot 1. The boot 1 according to the embodiment of the present invention is used for a joint that joins two members so as to be movable relative to each other, and is used for sealing the space covering the joint, and is used for sealing muddy water or dust from the outside. To prevent the ingress of foreign matter such as, etc., and to prevent the outflow of grease inside. The boot 1 is used, for example, as a universal joint of an automobile propeller shaft as described later.

The boot 1 includes a pair of annular mounting portions 10, 20 and a film portion 30 extending between the pair of mounting portions 10, 20. The film portion 30 is a flexible portion and has an inner surface 31 which is a surface facing the joint, an outer surface 32 which is a surface facing the inner surface 31, and a plurality of ribs 33. The rib 33 is a portion provided on at least one of the inner surface 31 and the outer surface 32 and projecting from this surface. The plurality of ribs 33 form at least two annular rows 34, and in each of the rows 34, the plurality of ribs 33 are arranged at intervals in the circumferential direction. In the pair of adjacent rows 34, the plurality of ribs 33 on one side of the pair of rows 34 and the plurality of ribs 33 on the other side of the pair of rows 34 are formed so as to be offset from each other in the circumferential direction. Hereinafter, the structure of the boot 1 will be specifically described.

As shown in FIGS. 1 and 2, the boot 1 extends along the axis x and extends around the axis x. The boot 1 is made of an elastic material such as rubber. In this description, for convenience of explanation, the side in the direction of the arrow a (see FIG. 1) in the axis x direction is the inside, and the side in the direction of the axis x in the direction of the arrow b (see FIG. 1) is the outside. The inside is the side facing the sealed space, the side facing the space covering the joint, and the outside is the atmosphere side. Further, in the direction perpendicular to the axis x (hereinafter, also referred to as “diameter direction”), the side away from the axis x (direction of arrow c in FIG. 1) is the outer peripheral side, and the direction approaching the axis x (FIG. 1). The side in the direction of arrow d) is the inner peripheral side.

As shown in FIGS. 1 and 2, the boot 1 has an inner mounting portion 10 and an outer mounting portion 20 as a pair of mounting portions. The inner mounting portion 10 is formed so as to be mountable on one of the two members to which the joint is joined, and the outer mounting portion 10 is formed so as to be mountable on the other of the two members to which the joint is joined. Specifically, the inner mounting portion 10 is provided inside the outer mounting portion 20, has a tubular shape centered on or substantially centered on the axis x, and is larger than the outer mounting portion 20. It is a part that forms a space of diameter on the inner circumference side. The outer mounting portion 20 has a tubular shape centered on or substantially centered on the axis x, and is a portion forming a space having a diameter smaller than that of the inner mounting portion 10 on the inner peripheral side. The inner mounting portion 10 is formed so as to be connected to one of the two members to which the joint is joined on the entire circumference. The outer mounting portion 20 is formed so as to be in contact with the other of the two members to which the joint is joined all around. Specifically, the inner mounting portion 10 is formed so that the end portion of the tubular adapter can be mounted, as will be described later.

The film portion 30 extends between the inner end 11 which is the inner end of the inner mounting portion 10 and the inner end 21 which is the inner end of the outer mounting portion 20 and extends along the axis x as shown in FIG. It has a curved portion 30a which is a portion curved or bent so as to project inward in a cross section along the cross section (hereinafter, also simply referred to as a cross section). The inner surface 31 of the film portion 30 is a surface facing inward, and faces a space covering the joint in the state of use of the boot 1 described later. The outer surface 32 of the film portion 30 is a surface facing the outside, and faces the atmosphere outside the space sealed by the boot 1 in the state of use of the boot 1, which will be described later. In the film portion 30, the inner surface 31 and the outer surface 32 face each other, and the distance between the inner surface 31 and the outer surface 32 is the extending direction of the film portion 30 between the inner mounting portion 10 and the outer mounting portion 20. Is constant or substantially constant.

As described above, the rib 33 is provided on at least one of the inner surface 31 and the outer surface 32, and is provided on the inner surface 31 as shown in FIGS. 1 and 2, for example. Each rib 33 projects from the inner surface 31 and extends in an arc shape or a substantially arc shape around the axis x. The ribs 33 are formed side by side at intervals g on each of the plurality of circumferences around the axis x, and a plurality of rows 34 formed by the ribs 33 are formed on the inner surface 31. In each row 34, the ribs 33 are arranged, for example, at regular intervals g.

As described above, in a pair of adjacent rows 34 of a plurality of rows 34 (see rows 34a, 34b of FIG. 1), a plurality of ribs 33 in one (34a) of the pair of rows and the other (34b) of the pair of rows. ) Are formed so as to be offset from each other in the circumferential direction. Specifically, in a pair of adjacent rows 34a and 34b of the plurality of rows 34, the plurality of ribs 33 in one of the pair of rows (row 34a) is the plurality of ribs 33 in the other (row 34b) of the pair of rows. Are arranged at positions where the plurality of intervals g, which are the portions where the rows 34 are not formed, overlap each other in the direction in which the rows 34 are lined up (axis x direction) (see FIG. 3). That is, all the ribs 33 in the row 34a correspond to all the spacing g in the row 34b in a one-to-one relationship, and each rib 33 in the row 34a corresponds to each corresponding spacing g in the row 34b in the axis x direction. It is arranged at a position where it overlaps with each other when viewed along the inner surface 31. It should be noted that the ribs 33 in the row 34a do not have to be arranged at positions where they overlap each other in the row 34b in a one-to-one relationship with the corresponding spacing g in the axis x direction along the inner surface 31. At least one rib 33 in the 34a may be arranged so as to overlap the corresponding spacing g in the row 34b when viewed along the inner surface 31 in the axis x direction.

In the plurality of columns 34, the intervals between the adjacent columns 34 are the same. That is, the distance (distance l) along the inner surface 31 in the axis x direction between the pair of adjacent rows 34 is constant among all the pair of adjacent rows 34. Further, the distance l along the inner surface 31 in the axis x direction between the pair of adjacent rows 34 does not have to be constant among all the pair of adjacent rows 34. For example, the row 34 located at the curved portion 30a and the row 34 located at the portion other than the curved portion 30a have different distances l along the inner surface 31 in the axis x direction between the pair of adjacent rows 34. May be good. Depending on the flexibility based on the shape of each portion of the film portion 30, the distance l along the inner surface 31 may be set in the axis x direction between the pair of adjacent rows 34, respectively. Thereby, each part of the film part 30 can have a desired flexibility.

As described above, a plurality of ribs 33 are arranged in the boot 1 so as to form a row 34, and each rib 33 suppresses deformation of the film portion 30 in the extending direction of the rib 33 (direction of the row 34). There is. Therefore, the film portion 30 of the boot 1 is less likely to be deformed in the circumferential direction, and the deformation of the film portion 30 in the radial direction is suppressed. Further, in the adjacent row 34, the ribs 34 are arranged so as to be displaced in the circumferential direction, and there is no portion in which the ribs 34 are not arranged in the circumferential direction of the film portion 30 (along the inner surface 32 in the axis x direction). Thereby, the radial expansion of the film portion 30 can be suppressed more effectively. Further, the ribs 33 are arranged at equal intervals in each row 34, whereby the radial expansion of the film portion 30 can be evenly prevented in the film portion 30.

On the other hand, the ribs 33 are formed in rows 34 arranged at intervals (distance 1) along the inner surface 31 of the film portion 30 in the axis x direction, and are formed between rows 34 of ribs 33 adjacent to each other. An interval (see interval S in FIG. 3) is formed. Due to this interval S, the film portion 30 of the boot 1 can easily expand and contract in the axis x direction. Further, in each row 34, the ribs 33 are arranged with an interval g. Due to this interval g, the film portion 30 is more easily deformed (bending deformation) so that the axis x is bent, as compared with the case where the ribs extending in an endless annular shape are arranged in the axial direction. As described above, in the boot 1, the deformation of the film portion 30 in the radial direction is suppressed, and the reduction of the elasticity of the film portion 30 in the axis x direction is suppressed, so that the film portion 30 is bent and deformed. The reduction in ease is suppressed.

The boot 1 is integrally formed of an elastic material, and the inner mounting portion 10, the outer mounting portion 20, and the film portion 30 are parts of the boot 1 integrally formed of the same elastic material.

Next, the operation of the boot 1 having the above configuration will be described. FIG. 4 is a diagram for showing the boot 1 in a used state attached to the propeller shaft 50 of an automobile, which is an example of an application target, and is along an axis x showing the vicinity of the universal joint 51 of the propeller shaft 50 in an enlarged manner. It is a cross-sectional view. The propeller shaft 50 is a known propeller shaft, and detailed description of its configuration will be omitted.

In the used state, as shown in FIG. 4, the boot 1 is attached to the shaft 52 as one of the two members to which the universal joint 51 as a joint is joined, and the shaft 53 as the other of the two members, and the universal joint 51 It is designed to form a closed space around it.

Specifically, the shaft 53 is inserted through the small-diameter outer mounting portion 20, the outer mounting portion 20 is fitted to the shaft 53, and the outer mounting portion 20 is in contact with the shaft 53 over the entire circumference. .. In this state, the boot band 54 is attached to the outer mounting portion 20 from the outer peripheral side, and the boot band 54 fixes the outer mounting portion 20 by pressing it against the shaft 53. The shaft 53 is connected to the universal joint 51 at the inner tip. The shaft 52 has a recess 52a at the outer end for accommodating the universal joint 51 on the inner peripheral side, and the shaft 52 is connected to the universal joint 51 by the recess 52a.

One end 55a of the tubular adapter 55 formed so as to be connectable to the tubular outer peripheral end 52b forming the recess 52a of the shaft 52 is attached to the large-diameter inner mounting portion 10, and the adapter The other end 55b of 55 is attached to the outer peripheral end 52b of the shaft 52. In this way, the inner mounting portion 10 is mounted on the shaft 52 via the adapter 55.

As described above, in the used state, the boot 1 is attached to the propeller shaft 50 to form a closed space around the universal joint 51. As a result, the boot 1 is intended to prevent foreign matter from entering the space from the outside, and to prevent the grease applied to the universal joint 51 from leaking to the outside from the space covering the universal joint 51. There is. As shown in FIG. 4, the inner surface 31 of the film portion 30 faces this space and faces the universal joint 51. On the other hand, the outer surface 32 of the film portion 30 faces the outside.

When the propeller shaft 50 rotates at a high speed in the operating state, the grease applied to the universal joint 51 is blown to the outer peripheral side by centrifugal force. The blown grease hits the inner surface 31 of the film portion 30 of the boot 1, and a pressing force for pushing the film portion 30 toward the outer peripheral side is applied to the inner surface 31 of the film portion 30. The pressing force by this grease tries to deform (expand) the film portion 30 toward the adapter 55 side, and tries to deform the film portion 30 in the radial direction. However, as described above, in the boot 1, the rib 33 makes it difficult for the film portion 30 to be deformed in the circumferential direction, and the expansion of the film portion 30 in the radial direction is suppressed. Therefore, even when the pressing force of the grease acts on the film portion 30, the film portion 30 is prevented from expanding in the radial direction, and the film portion 30 is prevented from being damaged by the pressing force of the grease. ing.

On the other hand, as described above, the film portion 30 of the boot 1 is easily expanded and contracted in the axis x direction due to the distance S (see FIG. 3) between the rows 34 of the ribs 33 adjacent to each other. Further, in each row 34, the ribs 33 are arranged with an interval g, and the film portion 30 is easily bent and deformed so that the axis x is bent due to the interval g. Therefore, the film portion 30 is suppressed from reducing the followability to the relative movement (swing or axial movement) between the shaft 52 and the shaft 53 as compared with the boot having no rib 33, or , Followability is not reduced. Further, the film portion 30 is suppressed in reducing the followability to the relative movement between the shaft 52 and the shaft 53, or the followability is not deteriorated, as compared with the boot having the endless annular rib. Therefore, even if the boot 1 has the rib 33, it can maintain high durability against the movement of the propeller shaft 50.

As described above, according to the boot 1 according to the embodiment of the present invention, the deformation of the film portion 30 due to the pressing force of the grease is suppressed while suppressing the decrease in the followability of the film portion 30 to the movements of the shafts 52 and 53. It can be suppressed. Thereby, the durability of the boot 1 can be improved, and the reduction of the sealing performance of the boot 1 can be suppressed.

Although the embodiment of the present invention has been described above, the present invention is not limited to the boot 1 according to the embodiment of the present invention, and all aspects included in the concept of the present invention and the scope of claims are included. Including. In addition, each configuration may be selectively combined as appropriate so as to achieve at least a part of the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment can be appropriately changed depending on the specific usage mode of the present invention.

For example, in each of the rows 34, the plurality of ribs 33 may not be arranged at equal intervals in the circumferential direction. Further, the cross-sectional shape of the film portion 30 is not limited to that shown in the drawing, and various forms can be used depending on the application target of the boot according to the present invention. Similarly, the shapes of the mounting portions 10 and 20 are not limited to those shown in the drawings, and various forms can be used depending on the application target of the boot according to the present invention. For example, the diameter of the inner mounting portion 10 and the diameter of the outer mounting portion 20 may be the same, and the diameter of the outer mounting portion 20 may be larger than the diameter of the inner mounting portion 10. Further, for example, the axis x is not a straight line as shown in the figure but a curved line, and the film portion 30 does not have to be rotationally symmetric.

Further, in the above example, the rib 33 is provided on the inner surface 31 of the film portion 30, but the rib 33 may be similarly provided on the outer surface 32 instead of the inner surface 31, and the rib 33 may be provided on the inner surface 31. In addition to this, the outer surface 32 may be similarly provided. Further, the rib 33 is not provided on the entire inner surface 31 or the outer surface 32, but may be provided in a part thereof.

Further, in the above example, the rib 33 has an arc shape extending in the circumferential direction, but the shape of the rib 33 is not limited to this, and various forms can be used. For example, as shown in FIG. 5A, the rib 33 may extend in a sinusoidal shape, and as shown in FIG. 5B, the rib 33 extends in a triangular wave shape. You may.

Further, as the application target of the boot 1 according to the embodiment of the present invention, a specific application target has been exemplified as described above, but the application target of the present invention is not limited to these, and other industrial machines and other industrial machines and the like. The present invention is applicable to all configurations that can utilize the effects of the present invention, such as general-purpose machines and vehicles.

1 ... Boots, 10 ... Mounting part (inner mounting part), 11 ... Inner end, 20 ... Mounting part (outer mounting part), 21 ... Inner end, 30 ... Membrane part, 30a ... Curved part, 31 ... Inner surface, 32 ... Outer surface, 33 ... ribs, 34, 34a, 34b ... rows, 50 ... propeller shafts, 51 ... universal joints, 52, 53 ... shafts, 52a ... recesses, 52b ... outer peripheral ends, 54 ... boot bands, 55 ... adapters, 55a , 55b ... end, g ... spacing, l ... distance, S ... spacing, x ... axis

Claims (5)

A boot used for a joint that joins two members so that they can move relative to each other.
A pair of annular mounting parts and
A film portion extending between the pair of mounting portions is provided.
The film portion has an inner surface which is a surface facing the joint, an outer surface which is a surface facing the inner surface, and a plurality of ribs.
The rib is a portion provided on at least one of the inner surface and the outer surface and projects from the surface.
The plurality of ribs form at least two annular rows.
In each of the rows, the plurality of ribs are spaced apart in the circumferential direction.
In the pair of adjacent rows, the plurality of ribs in one of the pair of rows and the plurality of ribs in the other of the pair of rows are formed so as to be offset from each other in the circumferential direction. boots. In the pair of adjacent rows, the ribs in one of the pair of rows are arranged so as to overlap the portion of the pair of rows in which the ribs are not formed in the direction in which the rows are lined up. The boot according to claim 1, wherein the boot is provided. In the pair of adjacent rows, the plurality of ribs in one of the pair of rows overlap each other in the direction in which the rows are arranged with the portion of the other of the pair of rows in which the plurality of ribs are not formed. The boot according to claim 1 or 2, wherein the boot is arranged in a position. The boot according to any one of claims 1 to 3, wherein in each of the rows, the plurality of ribs are arranged at equal intervals in the circumferential direction. The boot according to any one of claims 1 to 4, wherein the distance between the pair of adjacent rows is not the same.

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