JPH08247298A - Boot of hydraulic cylinder - Google Patents

Abstract

PURPOSE: To prevent the effusion of grease from mistaking the leakage of working oil from a hydraulic cylinder. CONSTITUTION: An annular skirt part 16 extending alog the outer periphery of a cylinder body 19 in an end of a boot 14 side formed with an annular projection 15 is spaced by a gap 19 from the cylinder body 12, and the annular projection 15 is formed with a gap 17 for reserving grease and a stopper part for blocking the annular projection 15 from the axial movement to an attaching groove 13. Thus, when the annular projection 15 is attached to the attaching groove 13, even the effusion of grease is prevented from being viewed from the outside by the skirt part 16 and the grease after the attachment can be prevented from the effusion to the outer peripheral part 12c of the cylinder body 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boot for a hydraulic cylinder which is attached to an opening end of a cylinder body of the hydraulic cylinder and prevents foreign matter from entering from the outside.

[0002]

2. Description of the Related Art For example, Japanese Utility Model Laid-Open No. 63-1
Japanese Patent No. 18461 discloses a boot of a hydraulic cylinder in which a mounting groove formed on the outer circumference of an opening end portion of a hydraulic cylinder body is mounted with an annular projection formed on the inner circumference at one end thereof.

Generally, when the annular protrusion of the boot is mounted in the mounting groove of the cylinder body, grease is applied to the annular protrusion or the mounting groove to facilitate the mounting. That is, the grease makes the lubrication between the outer periphery of the cylinder body and the annular protrusion of the boot good, and facilitates the mounting of the annular protrusion in the mounting groove.

However, after mounting the annular projection of the boot in the mounting groove, there was a problem that this grease squeezed out to the outer peripheral portion of the cylinder body and was mistakenly recognized as leaking hydraulic fluid of the hydraulic cylinder. Further, there is a problem that foreign matter such as dust is liable to adhere to the leaked grease, which causes rust in the cylinder body and deteriorates the boot sealing function.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a boot for a hydraulic cylinder that prevents the protrusion of grease from the outer periphery of the cylinder body from being mistaken for a leak of hydraulic fluid of the hydraulic cylinder. The purpose is to

[0006]

[Means for Solving the Problems] The above object is to form a mounting groove on the outer periphery of the opening end of the cylinder body of the hydraulic cylinder, and to mount the annular projection formed on the inner periphery of the mounting groove. In the boot of the hydraulic cylinder, the boot of the hydraulic cylinder is formed by forming an annular skirt portion extending along the outer circumference of the cylinder body at the end portion on the side where the annular protrusion is formed.

[0007]

[Operation] When mounting the annular protrusion formed on the inner circumference of the boot in the mounting groove formed on the outer circumference of the opening end of the cylinder body,
Even if the grease sticks out to the outer circumference of the cylinder body, it is covered with the annular skirt extending along the outer circumference of the cylinder body and is not visible to the outside. Further, by forming a gap between the skirt portion and the cylinder body, the grease is prevented from seeping out due to the capillary phenomenon. Further, by forming a gap between the side wall of the mounting groove and the annular protrusion, a grease reservoir is formed to prevent the grease from seeping out to the outside, and the gap prevents the annular protrusion from moving. By forming the stopper portion, the grease is prevented from exuding due to the movement of the annular protrusion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a hydraulic cylinder 11 to which a boot 14 according to the present invention is mounted. An annular groove formed on the inner circumference of one end of the boot 14 in a mounting groove 13 formed on the outer circumference of the opening end of the cylinder body 12. The protrusion 15 is attached. The inner circumference of the other end of the boot 14 is fixed to the input member 21, and the boot 14 expands and contracts as the input member 21 moves in the axial direction. One end of the input member 21 is engaged with the recess 20a of the piston 20, and the piston 20 is provided with cup seals 23 and 24 on its outer circumference so as to be slidable with respect to the inner hole 22 of the cylinder body 12. Is fitted to. In FIG. 1, the piston 20 is pushed to the right in the figure until the head portion 20b of the piston 20 abuts the inner wall bottom wall portion 12b of the cylinder body 12 against the spring force of the spring 25. The boot is shown in its most retracted state. In addition, although not shown, it is assumed that the hydraulic cylinder 11 is connected to a connection line for introducing hydraulic oil.

An annular skirt portion 16 extending along the outer periphery of the cylinder body is formed at the end of the boot 14 on the side where the annular protrusion is formed. The inner peripheral surface of this skirt portion 16 and the outer peripheral surface of the cylinder body are formed. A predetermined gap 19 is formed between and. As will be described later, this gap 19 is filled with grease by the capillary phenomenon due to the outer peripheral portion 12c of the cylinder body 12.
It is formed to the minimum without exuding. Further, as shown in FIGS. 2 and 3, on the skirt portion 16 side of the annular projection 15, there are six stopper portions 18 at equal intervals.
It is formed integrally with the annular protrusion 15, and further, a space 17 is formed between the annular protrusion 15 and the side wall 13 a of the mounting groove 13. The void 17 is a grease reservoir as described later, and prevents the grease from seeping out to the outer periphery of the cylinder body 12.

The boot 14 in this embodiment is constructed as described above, and its operation will be described below.

The boot 14 is mounted in the mounting groove 13 over the stepped portion 12a from the opening end side of the cylinder body 12 in a state where an appropriate amount of grease is applied to the annular projection 15 of the boot 14. At this time, by the time the annular protrusion 15 is mounted in the mounting groove 13, the grease applied to the annular protrusion 15 is in a state of being pushed out to the front of the mounting groove 13 (right side in the drawing). Here, in the above-described conventional boot shown in FIG. 5, there is a high possibility that the grease may go beyond the mounting groove as it is and protrude to the outer peripheral portion of the cylinder body. However, in this embodiment, since the annular skirt portion 16 is formed in the boot 14 with a proper gap 19 between the boot body 14 and the cylinder body 12, the protrusion of grease to the outer peripheral portion 12c of the cylinder body 12 is suppressed. . That is, the skirt portion 16 covers the movement of the grease beyond the side wall 13a of the mounting groove 13 so that the protruding grease is not visually recognized from the outside, and the gap between the skirt portion 16 and the cylinder body 12 is kept.
By forming 19 , the grease is prevented from seeping out to the outer peripheral portion 12c of the cylinder body 12 due to the capillary phenomenon.

Further, the width of the mounting groove 13 is formed with some margin from the width of the annular projection 15 in order to complete the mounting property of the annular projection 15, but the input member 2
When 1 moves in the axial direction, the boot 14 also expands and contracts, so that only the difference between the width of the mounting groove 13 and the width of the annular projection 15,
The annular protrusion 15 moves in the axial direction with respect to the mounting groove 13.
Therefore, the stopper portion 18 provided on the annular protrusion abuts on the side wall portion 13a of the mounting groove 13 to prevent the movement of the annular protrusion 15 and to move the annular protrusion 15 in the axial direction so that the grease of the cylinder main body 12 is prevented. The exudation to the outer peripheral portion 12c is prevented.

Further, the stopper portion 18 for the annular projection 15 is provided.
The space 17 formed along with the formation of the grease forms a grease reservoir, so that the grease is formed on the outer peripheral portion 1 of the cylinder body 12.
It is difficult to seep into 2c.

Due to the above-mentioned actions, the grease is kept on the outer peripheral portion 1 of the cylinder body 12 even when the boot 14 is attached to the cylinder body 12 and the hydraulic cylinder 11 is being operated.
2c can be prevented from leaking out, and the hydraulic fluid of the hydraulic cylinder 11 will not be mistakenly recognized as leaking.
Further, it is possible to prevent foreign matter from adhering to the outer peripheral portion 12c of the cylinder body 12 due to the exudation of grease and to prevent rust, and to prevent the function of the boot 14 from deteriorating.

The embodiment of the present invention has been described above.
Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the stopper portion 1
8 are formed on the annular projection 15 at six positions at equal intervals, but of course,
You may increase or decrease the number. Further, as shown in FIG. 4, the stopper portion 18 'may be formed in an annular shape. At this time, the space 17 ' formed between the side wall 13a of the mounting groove 13 and the annular projection 15' also has an annular shape, but it is clear that the same effect as that of the above-described embodiment can be obtained.

[0018]

As described above, according to the boot of the hydraulic cylinder of the present invention, there is no possibility that the grease leaks to the outer circumference of the cylinder body and is mistaken for the leakage of the hydraulic oil of the hydraulic cylinder. Further, it is possible to prevent the grease from seeping out to the outer circumference of the cylinder body, and it is possible to prevent foreign matter such as dust from adhering to the outer circumference of the cylinder body and rusting due to the seeping out of the grease.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an entire embodiment of the present invention.

FIG. 2 is a sectional view showing a boot of the hydraulic cylinder in the embodiment of the present invention.

3 is a view taken along the line [3]-[3] in FIG.

FIG. 4 is a sectional view of an essential part showing a modified example of the embodiment of the present invention.

[Explanation of symbols]

11 Hydraulic Cylinder 12 Cylinder Main Body 13 Mounting Groove 14 Boot 15 Annular Protrusion 16 Skirt 17 Gap 17 'Gap 18 Stopper 18' Stopper 19 Gap

Claims (4)

[Claims] 1. A boot for a hydraulic cylinder, wherein a mounting groove is formed on an outer periphery of an opening end portion of a cylinder body of the hydraulic cylinder, and an annular protrusion formed on an inner periphery at one end is mounted on the mounting groove. A boot of a hydraulic cylinder, wherein an annular skirt portion extending along the outer circumference of the cylinder body is formed at the end portion on the side where the ridge is formed. 2. The boot for a hydraulic cylinder according to claim 1, wherein a gap is formed between the skirt portion and the cylinder body. 3. A gap is formed between the side wall of the mounting groove and the annular protrusion, and a stopper portion for contacting the side wall of the mounting groove and preventing the movement of the annular protrusion due to the gap is formed on the annular protrusion. The boot for a hydraulic cylinder according to claim 1 or 2, wherein the boot is formed on a side surface. 4. The boot for a hydraulic cylinder according to claim 3, wherein the gap is a grease reservoir.