WO2020213278A1

WO2020213278A1 - Structure of vent and boot

Info

Publication number: WO2020213278A1
Application number: PCT/JP2020/009115
Authority: WO
Inventors: 卓麻廣田
Original assignee: Nok株式会社
Priority date: 2019-04-19
Filing date: 2020-03-04
Publication date: 2020-10-22
Also published as: JP2022120204A

Abstract

The present invention provides: a structure of a vent capable of preventing the entry of foreign matter such as water and dust from the outside and preventing grease and the like from flowing out, without hindering the release of gas to the outside; and a boot.　Provided is a structure of a vent 115 of an elastic boot main body 110, the structure of the vent 115 being provided on a surface of the inner peripheral surface side of a first fixing portion 111 fixed to an outer peripheral surface of a first shaft member 200 and being capable of releasing gas inside a boot 100 to the outside. The structure of the vent 115 is characterized in that a surface of the vent 115 is provided with a plurality of protrusions having different sizes.

Description

Vent structure and boots

The present invention relates to a vent structure and boots applied to boots provided in constant velocity universal joints.

In boots provided with constant velocity universal joints, the air pressure inside the boots may become abnormally high. For example, in the case of a constant velocity universal joint applied to a propeller shaft, since it rotates at a high speed (for example, 4000 rpm or more), the temperature inside the boot rises and the atmospheric pressure rises. Therefore, if the boot is sealed with a large amount of air in the boot when it is attached, the air pressure inside the boot may become abnormally high when the temperature becomes high. As a result, the boots may expand and the boots may not perform their original functions. Therefore, a technique is known in which the gas in the boot is released to the outside by providing a vent in the joint or the boot.

When a vent is provided in a joint, the cost is generally high due to a large number of parts, and there is a problem that foreign matter such as water or dust easily enters from the outside. Further, even when the boot is provided with a vent, there is a problem that foreign matter such as water or dust easily invades from the outside and grease leaks to the outside. As a countermeasure, if the vent is made smaller, it becomes difficult for the gas to escape.

Japanese Unexamined Patent Publication No. 2004-156689 Japanese Unexamined Patent Publication No. 2006-349010

An object of the present invention is to provide a vent structure and boots capable of suppressing the invasion of foreign substances such as water and dust from the outside and suppressing the outflow of grease and the like without hindering the release of gas to the outside. It is in.

The present invention has adopted the following means to solve the above problems.

That is, the structure of the vent of the present invention is
Among the annular members made of elastic bodies, the structure of the vent is provided on the inner peripheral surface side of one end portion fixed to the outer peripheral surface of the shaft member and can release the gas inside the annular member to the outside. hand,
The surface of the vent is characterized by being provided with a plurality of protrusions having different sizes.

According to the present invention, since a plurality of protrusions having different sizes are provided on the surface of the vent, foreign matter such as water and dust can be suppressed from the outside, and the outflow of grease and the like can be suppressed. A gas passage can be secured.

The plurality of protrusions have small protrusions that shift from a state of being in close contact with the outer peripheral surface of the shaft member to a state of being separated from the state of being in close contact with the outer peripheral surface of the shaft member when the air pressure inside the annular member is increased, and even if the air pressure inside the annular member is increased. It is preferable that a large protrusion that maintains a state of being in close contact with the outer peripheral surface of the shaft member is included.

As a result, when the air pressure inside the annular member becomes high, the small protrusions are separated from the outer peripheral surface of the shaft member, so that the gas passage can be more reliably secured. On the other hand, the large protrusions are maintained in close contact with the outer peripheral surface of the shaft member even when the air pressure inside the annular member rises, so that foreign matter such as water and dust can be more reliably suppressed from the outside and grease. The outflow of such substances can be suppressed more reliably.

The boots of the present invention
In boots that are provided in a constant velocity universal joint that transmits rotation between two shaft members at a constant velocity, suppress foreign matter from entering the joint mechanism, and prevent grease from flowing out from the joint mechanism.
One end side is fixed to one of the two shaft members, and the one shaft member can follow and deform when it swings relative to the other shaft member of the two shaft members. An annular and elastic boot body,
An adapter whose one end side is fixed to the other end side of the boot body and whose other end side is fixed to the outer race provided on the other shaft member side.
With
The boot body is characterized in that the structure of the vent is provided on the inner peripheral surface side surface of one end portion fixed to the one shaft member.

As described above, according to the present invention, it is possible to suppress the invasion of foreign substances such as water and dust from the outside and the outflow of grease and the like without hindering the release of gas to the outside.

FIG. 1 is a schematic cross-sectional view of the boot according to the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a constant velocity universal joint to which the boot according to the first embodiment of the present invention is applied. FIG. 3 is a partially enlarged perspective view of the boot according to the first embodiment of the present invention. FIG. 4 is a perspective view of the vent according to the first embodiment of the present invention. FIG. 5 is an explanatory view of the mechanism of the vent according to the first embodiment of the present invention. FIG. 6 is a perspective view of a vent according to a second embodiment of the present invention.

Hereinafter, a mode for carrying out the present invention will be described in detail exemplarily based on examples with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to those, unless otherwise specified. .. The structure of the vent according to the present invention can be applied to various annular members made of elastic bodies such as a boot body of a boot provided in a constant velocity universal joint and a dust cover provided in a ball joint. In the following description, a case where the structure of the vent according to the present invention is applied to the boot body of the boot provided in the constant velocity universal joint will be described as an example.

(Example 1)
The vents and boots according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a schematic cross-sectional view of the boot according to the first embodiment of the present invention. Note that FIG. 1 shows a cross-sectional view of the boot cut along a surface including the central axis of the boot. FIG. 2 is a schematic cross-sectional view of a constant velocity universal joint to which the boot according to the first embodiment of the present invention is applied. FIG. 2 also shows a cross-sectional view of the boot or the like cut along the surface including the central axis of the boot. FIG. 3 is a partially enlarged perspective view of the boot according to the first embodiment of the present invention, and is an enlarged perspective view of the vicinity where the vent is provided. FIG. 4 is a perspective view of the vent according to the first embodiment of the present invention. FIG. 5 is an explanatory view of the mechanism of the vent according to the first embodiment of the present invention.

<Constant velocity universal joint>
In particular, the constant velocity universal joint according to the present embodiment will be described with reference to FIG. The constant velocity universal joint 10 includes two shaft members and a joint mechanism 320 that transmits rotation between the two shaft members at a constant velocity. Hereinafter, one of the two shaft members will be referred to as a first shaft member 200, and the other shaft member will be referred to as a second shaft member 300. The second shaft member 300 includes an outer race 310, and a joint mechanism 320 is provided inside the outer race 310. In FIG. 2, the joint mechanism 320 is simply shown. As the joint mechanism 320, various known techniques such as a mechanism provided with a spherical roller and a needle-shaped roller and a mechanism provided with a plurality of steel balls between the inner race and the inner race and the outer race 310 can be applied. Further, the first shaft member 200 and the second shaft member 300 are configured to be relatively reciprocating and swinging within a certain range.

The constant velocity universal joint 10 is provided with boots 100 that suppress the intrusion of foreign matter (water or dust) into the joint mechanism 320 and prevent the grease from flowing out from the joint mechanism 320.

<Boots>
In particular, the boot 100 according to this embodiment will be described in more detail with reference to FIGS. 1 and 2. The boot 100 is composed of a boot body 110 made of an elastic body such as rubber and an adapter 120 made of metal. One end of the boot body 110 is fixed to the first shaft member 200. The boot body 110 is composed of an annular member that can follow and deform when the first shaft member 200 swings relative to the second shaft member 300. Further, the boot body 110 is provided with a first fixing portion 111 as one end portion which is provided on one end side and is fixed to the outer peripheral surface of the first shaft member 200, and a curvature provided for easy follow-up deformation. It includes a portion 112 and a second fixing portion 113 provided on the other end side and fixed to the adapter 120. An annular groove 114 is provided on the outer peripheral surface side of the first fixing portion 111. By tightening the band 130 in the annular groove 114, the first fixing portion 111 is securely fixed by the first shaft member 200. A vent 115 capable of discharging the gas inside the boot 100 to the outside is provided on the surface of the first fixing portion 111 on the inner peripheral surface side.

The adapter 120 is composed of an annular member having a tubular body portion whose one end side is fixed to the second fixing portion 113 on the other end side of the boot body 110 and whose other end side is fitted and fixed to the outer race 310. There is. The adapter 120 is made of, for example, metal. And more specifically, the adapter 120 has a stepped cylindrical portion. The cylindrical portion has a cylindrical portion 121 having a small diameter and a cylindrical body portion 122 having a diameter larger than that of the cylindrical portion 121 and fitted and fixed to the outer race 310. Further, the adapter 120 includes a crimping fixing portion 123 in which one end side of the cylindrical portion 121 is crimped and fixed to the second fixing portion 113 of the boot body 110. Further, at the tip on the other end side of the adapter 120, an engaging protrusion 124 that engages with the recess 311 formed on the outer peripheral surface of the outer race 310 is also provided.

<Ventilation port>
In particular, the vent 115 according to this embodiment will be described with reference to FIGS. 3 to 5. As described above, the vent 115 is provided on the surface of the first fixing portion 111 on the inner peripheral surface side. The vent 115 according to the present embodiment is provided on a part of the inner peripheral surface of the first fixed portion 111 in a region that is in close contact with the outer peripheral surface of the first shaft member 200 over almost the entire circumference. There is. More specifically, the vent 115 is formed by a groove extending in the axial direction and communicating the inside and the outside of the boot body 110. The vents 115 may be provided at only one place, or may be provided at a plurality of vents 115 at intervals in the circumferential direction. The inner peripheral surface of the first fixed portion 111 is in close contact with the outer peripheral surface of the first shaft member 200 over the entire circumference except for a part in the region where the vent 115 is provided.

Then, on the surface of the vent 115 according to this embodiment, a plurality of protrusions having different sizes are provided. More specifically, when the air pressure inside the boot 100 becomes high, the small protrusion 115b shifts from the state of being in close contact with the outer peripheral surface of the first shaft member 200 to the state of being separated from the state, and even if the air pressure inside the boot 100 becomes high. A plurality of large protrusions 115a that maintain a state of being in close contact with the outer peripheral surface of the first shaft member 200 are provided. Both the large protrusion 115a and the small protrusion 115b have a hemispherical shape.

FIG. 5 shows the behavior of the inner peripheral surface of the vent 115 when the air pressure inside the boot 100 changes from a normal state (upper figure) to a high state (lower figure). When the atmospheric pressure is in a normal state, both the large protrusion 115a and the small protrusion 115b are in close contact with the outer peripheral surface of the first shaft member 200. On the other hand, when the air pressure inside the boot 100 becomes high, the boot body 110 expands and expands radially outward. As a result, the small protrusion 115b is separated from the outer peripheral surface of the first shaft member 200. On the other hand, the large protrusion 115a maintains a state of being in close contact with the outer peripheral surface of the first shaft member 200.

<Superior points of the vent structure according to this embodiment>
According to the structure of the vent 115 according to the present embodiment, since a plurality of protrusions having different sizes are provided on the surface of the vent 115, it is possible to suppress the intrusion of foreign matter such as water and dust from the outside, and also. It is possible to secure a gas passage while suppressing the outflow of grease and the like. As a result, air can be released to the outside when the boot 100 is assembled to the first shaft member 200 or the like.

Further, in this embodiment, when the air pressure inside the boot 100 becomes high, the small protrusion 115b that shifts from the state of being in close contact with the outer peripheral surface of the first shaft member 200 to the state of being separated from the state, and the air pressure inside the boot 100 become high. However, a plurality of large protrusions 115a that maintain a state of being in close contact with the outer peripheral surface of the first shaft member 200 are provided.

As a result, when the air pressure inside the boot 100 becomes high, the small protrusion 115b is separated from the outer peripheral surface of the first shaft member 200, so that the gas passage can be more reliably secured. Further, since the large protrusion 115a is maintained in close contact with the outer peripheral surface of the first shaft member 200 even when the air pressure inside the boot 100 becomes high, the invasion of foreign matter such as water and dust from the outside is more reliably suppressed. However, the outflow of grease and the like can be suppressed more reliably.

As described above, according to the structure of the vent 115 according to the present embodiment, the invasion of foreign substances such as water and dust is suppressed from the outside without hindering the release of gas to the outside, and the outflow of grease and the like is prevented. It can be suppressed. Along with this, the boot body 110 is suppressed from being abnormally expanded, so that the original function of the boot 100 can be stably exhibited.

(Example 2)
FIG. 6 shows Example 2 of the present invention. In the first embodiment, the case where the protrusions provided on the surface of the vent are hemispherical is shown, but in this embodiment, the configuration when the shapes of the protrusions are different is shown. Since the configuration described in the first embodiment can be applied to the configurations other than the vents, the description thereof will be omitted.

FIG. 6 is a perspective view of the vent according to the second embodiment of the present invention. As described above, the configuration described in the first embodiment can be applied as it is to the configurations other than the vents. The vent 115X according to the present embodiment is also formed by a groove extending in the axial direction and communicating the inside and the outside of the boot body 110, as in the case of the first embodiment.

Then, on the surface of the vent 115X according to this embodiment, a plurality of protrusions having different sizes are provided. More specifically, when the air pressure inside the boot 100 becomes high, the small protrusion 115Xc shifts from the state of being in close contact with the outer peripheral surface of the first shaft member 200 to the state of being separated from the state, and even if the air pressure inside the boot 100 becomes high. A plurality of large protrusions 115Xa and a plurality of large protrusions 115Xb that maintain a state of being in close contact with the outer peripheral surface of the first shaft member 200 are provided.

In the case of this embodiment, a pair of substantially L-shaped large protrusions 115Xa provided on both sides of the vent 115X in the width direction and a substantially T-shaped large protrusion 115Xb provided between the pair of large protrusions 115Xa. , A plurality of sets of protrusion groups are arranged side by side with five protrusions consisting of a pair of small protrusions 115Xc provided between the large protrusion 115Xa and the large protrusion 115Xb as one set.

Even in the structure of the vent 115X according to the present embodiment configured as described above, the same effect as in the case of the first embodiment can be obtained.

(Other)
The shape of the protrusion according to the present invention is not limited to the shape shown in each of the above examples. Further, in the case of the above embodiment, the plurality of protrusions provided on the surface of the vent are provided so as to be aligned, but the plurality of protrusions in the present invention may not be aligned. That is, the plurality of protrusions may be randomly arranged.

Further, in the above embodiment, an example is shown in which two types of large protrusions and small protrusions are provided with the protrusion amount (height) of the protrusions. However, for a plurality of protrusions having different sizes in the present invention, the amount of protrusion may be three or more. Further, in the above embodiment, the small protrusions are configured to be in close contact with the outer peripheral surface of the first shaft member 200 when the atmospheric pressure is in a normal state. However, in the present invention, microprojections may be provided so as to maintain a state away from the outer peripheral surface of the first shaft member 200 regardless of the magnitude of atmospheric pressure.

10 Constant velocity universal joint 100 Boot 110 Boot body 111 1st fixed part 112 Curved part 113 2nd fixed part 114

Circular groove

115, 115X Vent 115a, 115Xa, 115Xb Large protrusion 115b, 115Xc Small protrusion 120 Adapter 121 Cylindrical part 122 Body Part 123 Clamping fixing part 124 Engagement protrusion 130 Band 200 1st shaft member 300 2nd shaft member 310 Outer race 311 Recessed 320 Joint mechanism

Claims

Among the annular members made of elastic bodies, the structure of the vent is provided on the inner peripheral surface side of one end portion fixed to the outer peripheral surface of the shaft member and can release the gas inside the annular member to the outside. hand,
The structure of the vent is characterized in that a plurality of protrusions having different sizes are provided on the surface of the vent.
The plurality of protrusions have small protrusions that shift from a state of being in close contact with the outer peripheral surface of the shaft member to a state of being separated from the state of being in close contact with the outer peripheral surface of the shaft member when the air pressure inside the annular member is increased, and even if the air pressure inside the annular member is increased. The structure of a vent according to claim 1, wherein a large protrusion that maintains a state of being in close contact with the outer peripheral surface of the shaft member is included.
In boots that are provided in a constant velocity universal joint that transmits rotation between two shaft members at a constant velocity, suppress foreign matter from entering the joint mechanism, and prevent grease from flowing out from the joint mechanism.
One end side is fixed to one of the two shaft members, and the one shaft member can follow and deform when it swings relative to the other shaft member of the two shaft members. An annular and elastic boot body,
An adapter whose one end side is fixed to the other end side of the boot body and whose other end side is fixed to the outer race provided on the other shaft member side.
With
A boot characterized in that the structure of the vent according to claim 1 or 2 is provided on the surface of the boot body on the inner peripheral surface side of one end portion fixed to the one shaft member.