JP2007120724A - Connecting structure of hose fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure of a non-skiving type hose fitting allowing the fitting to be connected at small number of processes without needing to shave off a cover rubber layer in connecting the hose fitting, and ensuring high durability after connection. <P>SOLUTION: In this connection structure of the hose fitting 22, the hose fitting 22 having an insert fitting 26 comprising a nipple 24, and a sleeve fitting 28 comprising a plurality of annular protrusions 40 is fixed and connected to the end of a rubber hose 10 for high pressure by caulking the sleeve fitting 28 in a diameter reducing direction. In this case, the sleeve fitting 28 is provided with a cover presser 46 for pressing the cover rubber layer 20 radially inward in a caulked state, and an annular groove 52 is formed on the outer peripheral surface of the nipple 24 of the insert fitting 26 and in a position radially opposed to the cover presser 46. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a connection structure between a high-pressure rubber hose and a hose fitting.

Conventionally, as a high-pressure rubber hose (for example, the maximum operating pressure is 34.5 MPa), a laminated structure of an inner rubber layer, a wire reinforcing layer, a cover rubber layer, and a lower thread layer provided on the outer peripheral surface of the inner rubber layer is formed. A rubber hose (hereinafter simply referred to as a hose) is used.
As a connection structure of the hose fitting to the high pressure hose, conventionally, a hose fitting having an insert fitting having a nipple portion and a sleeve fitting is used, and the hose end cover rubber layer is buffed and scraped off. Insert the nipple part of the insert fitting into the inside of the end, and in this state, crimp the sleeve fitting in the direction of diameter reduction from the outer periphery of the wire reinforcement layer. The connection structure of the hose metal fitting which fixes the hose metal fitting in a state where it is sandwiched from the outside has been widely used.

This connection structure is a so-called skive connection structure, and a specific example thereof is shown in FIG.
In the figure, 200 is a high pressure hose, 202 is an inner rubber layer, 204 is a lower yarn layer applied to the outer peripheral surface, 206 is a wire reinforcing layer, and 208 is a cover rubber layer.
A hose fitting 210 includes an insert fitting 214 having a nipple portion 212 and a sleeve fitting 216.

In the connection structure of the hose fitting 210, as shown in FIG. 7, the cover rubber layer 208 at the end of the hose 200 is scraped to expose the wire reinforcing layer 206, and the nipple portion 212 of the insert fitting 214 is connected to the hose 200. The sleeve fitting 216 and the insert fitting 214 are fixed and connected to the end of the hose 200 by being inserted into the end portion and caulked in the diameter reducing direction from the outer peripheral side of the wire reinforcing layer 206 where the sleeve fitting 216 is exposed. .
However, in the case of the connection structure of the hose fitting 210, the cover rubber layer 208 has to be scraped for the fixed connection of the hose fitting 210, which requires a lot of man-hours for the connection of the hose fitting 210 and increases the cost. There's a problem.

On the other hand, in recent years, a non-skive connection structure that can connect the hose fitting 210 without removing the cover rubber layer 208 has been adopted.
FIG. 8A shows a specific example.
In the figure, the sleeve fitting 218 is provided with a plurality of annular protrusions 220 and an annular groove 222 between them on the inner peripheral side.

In the connection structure of the hose fitting 210 shown in FIG. 8A, the cover rubber layer 208 at the end of the hose 200 is left as it is without being scraped, and the sleeve fitting 218 is reduced in diameter from the outer peripheral side of the cover rubber layer 208. It is caulked in the direction, and this is fixed in a state where the end portion of the hose 200 is sandwiched together with the nipple portion 212.
At this time, the annular protrusion 220 of the sleeve metal fitting 218 penetrates the cover rubber layer 208 and reaches the wire reinforcing layer 206, and enters the wire reinforcing layer 206, thereby fixing the end portion of the hose 200.

As shown in the partially enlarged view of FIG. 8B, the sleeve metal fitting 218 is caulked in its inner peripheral surface, more specifically, the groove bottom surface of the annular groove 222 and the rear end on the rear side of the final annular protrusion 220. The inner peripheral surface of the portion 224 does not press the cover rubber layer 208 inward in the radial direction, and is substantially flush with the outer peripheral surface of the cover rubber layer 208.
In the case of the connection structure of the non-skive hose fitting 210, the cover rubber layer 208 at the end of the hose 200 does not have to be scraped in advance when the fitting is connected, and the required man-hours for fitting the fitting are reduced, thereby reducing the cost. be able to.

However, this non-skive type hose fitting connection structure has a problem that it is inferior in terms of durability compared to the above-mentioned skive type hose fitting connection structure.
In the connection structure of the conventional skive hose fitting 210 shown in FIG. 7, the cover rubber layer 208 does not exist between the sleeve fitting 216 and the wire reinforcing layer 206, and the sleeve fitting 216 directly connects the wire reinforcing layer 206. Although it is pressed inward in the radial direction and has a large contact area (pressing area) with respect to the wire reinforcing layer 206, the wire reinforcing layer 206 is firmly held, but the non-skive hose fitting 210 shown in FIG. In the case of this connection structure, the cover rubber layer 208 exists between the inner peripheral surface of the sleeve fitting 218 and the wire reinforcement layer 206, and the contact area between the annular projection 220 of the sleeve fitting 218 and the wire reinforcement layer 206 is small. Therefore, when the hose 200 is used, when the internal pressure suddenly and repeatedly acts and the hose 200 pulsates, the elasticity of the cover rubber layer 208 is increased. There partially large strain hose 200 is repeatedly significantly deformed by the fixing portion near by the hose fitting 210 with a shape, it is liable to occur stress concentration. Refer to FIG.
And it is thought that durability falls in the connection structure of the non-skive type hose metal fitting 210 shown to FIG. 8 (A).

Therefore, the present inventor has devised a configuration in which the rear end portion of the sleeve fitting 218 is configured as a cover presser 226 that presses the cover rubber layer 208 inward in the radial direction as shown in FIG. Disclosed in Japanese Patent Application (Patent Document 1).
Here, the cover retainer 226 has its inner peripheral surface, that is, the pressing surface 228 positioned radially inward from the groove bottom surface of the annular groove 222 between the annular protrusions 220 and 220, and the sleeve fitting 218 is caulked. The cover rubber layer 208 is pressed in a compressed state in the radial direction.
By providing such a cover presser 226 in the sleeve metal fitting 218, a certain effect can be obtained in improving the durability.

However, the durability of some varieties is still insufficient and a solution has been sought.
Specifically, when the hose diameter, that is, the diameter of the sleeve fitting 218 is small, when the caulking ratio is caulked in the reduced diameter direction at the same caulking rate as that of the large diameter sleeve fitting 218, the axial expansion due to plastic deformation causes the sleeve having a large diameter. The inner rubber layer 202 and the lower yarn layer 204 that is applied to the outer peripheral surface of the inner rubber layer 202 and integrated with the inner rubber layer 202 are greatly pulled in the axial direction by caulking the sleeve metal fitting 218. , It will be in a state of elongation.

When the hose 200 pulsates in such a state, the lower yarn layer 204 cannot endure and breaks.
The lower yarn layer 204 also functions as a reinforcing material layer for the inner rubber layer 202. When the lower yarn layer 204 breaks, the inner rubber layer 202 breaks early without being able to withstand high pressure. End up.
And it became clear by this inventor's various tests that this is the cause of reducing the durability of the hose 200.

  On the other hand, when the caulking rate of the sleeve metal fitting 218 is reduced, the fixing force between the hose metal fitting 210 and the hose 200 becomes weak, which causes a problem that the metal fitting is detached.

JP 2003-287178 A

  The present invention is based on the circumstances as described above, and it is not necessary to scrape the cover rubber layer when connecting the hose metal fittings. It was made for the purpose of providing the connection structure of hose metal fittings.

  Thus, the present invention provides a high-pressure rubber hose having a laminated structure of an inner rubber layer, a wire reinforcing layer, a cover rubber layer, and a lower yarn layer provided on the outer peripheral surface of the inner rubber layer. A hose fitting having an insert fitting provided with a nipple portion, and a plurality of annular protrusions provided at intervals in the axial direction and a sleeve fitting provided with an annular groove between the annular protrusions on the inner peripheral side, By caulking the sleeve fitting in the diameter reducing direction, the annular projection penetrates the cover rubber layer and bites into the wire reinforcing layer, and the sleeve hose and the insert fitting are fixed so that the end of the rubber hose is sandwiched from both inside and outside. In the connection structure of the hose fitting to be connected, the diameter of the cover rubber layer is caulked in the further rear part of the annular projection at the rear end in the direction away from the hose front end in the axial direction. A cover presser for pressing inward is provided on the sleeve metal fitting, and is pressed by the cover presser on the outer peripheral surface of the nipple portion of the insert metal fitting and at a position facing the cover presser in the radial direction. Further, an annular groove for inserting the inner rubber layer at the end of the rubber hose is provided, and a portion sandwiched between the cover retainer and the nipple portion at the end of the rubber hose by the cover retainer and the annular groove is formed in a radial direction and an axial direction. It is characterized in that it is made to act as a restraint.

  According to a second aspect of the present invention, in the first aspect of the present invention, the cover retainer is characterized in that the inner circumferential pressing surface is positioned radially inward from the groove bottom surface of the annular groove.

Effects and effects of the invention

As described above, according to the present invention, in the connection structure of the non-skive hose fitting, the cover retainer for pressing the cover rubber layer radially inward is provided on the sleeve fitting and further on the rear portion of the annular protrusion at the rear end. An annular groove is provided on the outer peripheral surface of the nipple portion of the insert fitting at a position facing the cover presser in the radial direction.
Here, the cover presser can be provided continuously to the annular protrusion at the final position, or can be provided at the rear part thereof at a small distance.

In the present invention, this cover presser presses the cover rubber layer surface in the direction of reducing the diameter with a press rate of 30% or more of the wall thickness of the cover rubber layer.
Here, the pressing rate is a pressing rate at the start end of the cover presser on the annular projection side.

In the present invention, a part of the inner rubber layer enters the inside of the annular groove of the nipple portion with elastic deformation due to the pressing action inward in the radial direction by the cover presser, and physically in the axial direction with respect to the annular groove. Is engaged.
And by this physical engagement, the inner rubber layer is subjected to a restraining action in the axial direction, and is applied to the inner rubber layer and its outer peripheral surface along with the axial extension of the sleeve fitting when the sleeve fitting is caulked. The lower yarn layer is restrained from extending in the axial direction, and at the time of hose pulsation, the inner rubber layer, specifically, the inner rubber layer of the portion sandwiched between the nipple portion of the insert fitting and the sleeve fitting pulsates in the axial direction. Is suppressed.

Furthermore, the pulsation of the end portion of the hose, specifically, the portion sandwiched in the radial direction between the cover presser and the nipple portion, is also suppressed in the radial direction by the pressing action of the cover presser inward in the radial direction.
Thus, by suppressing the pulsations in the axial direction and the radial direction, generation of large strains and stress concentration are suppressed, thereby effectively improving the durable life of the hose.

The cover presser not only simply restrains the hose end portion in the radial direction but also forcibly pushes a part of the inner rubber layer into the annular groove of the nipple portion.
As a result, the physical engagement force in the axial direction between the inner rubber layer and the annular groove becomes larger, and as a result, the axial pulsation of the inner rubber layer is more effectively suppressed.

Part of the inner rubber layer that has entered the annular groove has the function of suppressing the axial pulsation of the inner rubber layer by the axial physical engagement force with the annular groove, and the same part as the hose itself pulsates. It also has the function of absorbing or blocking the vibration that has propagated to the hose, which is considered to contribute to the improvement of the durability of the hose.
Here, it is desirable that the annular groove has a groove depth of 0.2 to 1.0 mm and a groove width of 1.0 to 6.0 mm.

  In the present invention, the cover presser can have its inner peripheral pressing surface positioned radially inward from the groove bottom surface of the annular groove (Claim 2).

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, reference numeral 10 denotes a high pressure hose having a laminated structure of an inner rubber layer 12, a lower yarn layer 14, an intermediate rubber layer 16, a wire reinforcing layer 18 and a cover rubber layer 20 applied to the outer peripheral surface thereof. Yes.
Here, the inner rubber layer 12 is made of NBR, and the cover rubber layer 20 is made of SBR.
Here, the lower yarn layer 14 is formed by braiding a lower yarn (PET yarn) with a blade, and NBR is used as an intermediate rubber layer 16 on the outer side.
The wire reinforcing layer 18 is formed by spirally winding a wire into a plurality of layers.

In this embodiment, the hose 10 has an inner diameter of φ12.7 mm and an outer diameter of φ22.9 mm.
Further, the cover rubber layer 20 has a thickness of 1.2 mm, and the inner rubber layer 12 has a thickness of 1.35 mm.

Reference numeral 22 denotes a hose fitting having an insert fitting 26 having a nipple portion 24 inserted into the end of the hose 10 and a sleeve fitting 28.
Reference numeral 30 denotes a cap nut for screwing the insert fitting 26 to the counterpart device side.

The nipple portion 24 has an uneven shape with a substantially sawtooth cross-sectional shape, and a plurality of shallow annular recesses 32 are formed at predetermined intervals in the axial direction.
The insert fitting 26 has a large-diameter hexagonal tool hook 34, and an annular locking groove 36 is provided at an adjacent position.

In the insert metal fitting 26, the inner diameter _{D 1} of the nipple portion 24 Fai9.5Mm, the outer diameter _{D 2} is Fai13.0Mm (see FIG. 2 (B)).
The other sleeve fitting 28 is provided with an inward annular locking protrusion 38 at the front end in the axial direction (left end in the figure), and this annular locking protrusion 38 fits into the annular locking groove 36 in the insert fitting 26. And locked.

FIG. 2A shows the sleeve metal fitting 28 in a shape before caulking. As shown in the figure, the sleeve metal fitting 28 has a plurality of annular projections 40 on the inner peripheral side at predetermined intervals in the axial direction. In addition, a plurality of annular grooves 42 are provided between the annular protrusions 40 and 40.
An annular groove 44 is also formed between the annular projection 40 on the most front end side and the annular locking projection 38.
Here, the front surface (left side surface in the figure) of each annular protrusion 40 forms a tapered surface with an angle θ ₁ (here, θ ₁ = 75 °), and the rear surface (right side surface in the figure) has an angle θ ₂ (here, and a tapered surface of θ ₂ = 70 °).

Each annular protrusion 40 has a square shape at the front end and the rear end of the inner periphery. Here, as for each annular groove 42, all groove bottom faces are located in the same position in radial direction.
Each annular protrusion 40 has the same protruding height inward in the radial direction.
Note The sleeve component 28, in the caulking shape before the inner diameter _{D 3} shown in FIG. 2 (A) (ii) Fai29mm, the outer diameter _{D 4} is a Fai31.8Mm.
The sleeve component 28, the axial length _{L 2} is a 40 mm (see FIG. 2 (A) (b)).
One of the insert fitting 26 Note the length dimension L ₁ of the annular locking groove 36 to axially rear end (right end in the drawing) there is a 50 mm (see FIG. 2 (B)).

  The sleeve fitting 28 is also provided with a cover rubber layer of the hose 10 in a state of being squeezed onto the annular protrusion 40 at the final position, more specifically, at the rear of the annular protrusion 40 at the final position in the axial direction away from the front end of the hose 10. A cover presser 46 is provided to press 20 inward in the radial direction. Here, the cover presser 46 is provided continuously to the annular protrusion 40 at the final position.

The inner peripheral surface of the cover presser 46 is a pressing surface 48 that presses the cover rubber layer 20 radially inward.
Here, the pressing surface 48 is positioned radially inward from the groove bottom surface of the annular groove 42.
Specifically, the radial dimension difference a between the left end of the pressing surface 48 in the drawing, that is, the root of the annular protrusion 40 and the groove bottom surface of the annular groove 42 is 0.95 mm on one side.

As shown in FIG. 1B, the pressing surface 48 is a tapered surface having an angle θ ₃ (here, θ ₃ = 5 °).
Further, the rear end of the pressing surface 48 is an arc-shaped curved surface 50 having a radius of 1 mm.
On the other hand, an annular groove 52 is formed in the nipple portion 24 of the insert fitting 26 at a position facing the cover presser 46 in the radial direction.
In this embodiment, the annular groove 52 has a groove depth b shown in FIG. 1B of 0.3 mm and a groove width c of 2 mm.

  In this embodiment, the annular groove 52 has a rectangular cross section, but may have a trapezoidal cross section as shown in FIG.

  In this embodiment, as shown in FIG. 4, the nipple portion 24 of the insert fitting 26 is inserted into the end portion of the hose 10, and the cover rubber layer 20 at the end portion of the hose 10 is left as it is without being scraped off. The hose fitting 22 is fixed and connected to the hose 10 by caulking the sleeve fitting 28 in the diameter-reducing direction from the outer peripheral side of the cover rubber layer 20.

At this time, as shown in FIG. 1, the annular locking projection 38 of the sleeve metal fitting 28 is fitted into the annular locking groove 36 of the insert metal fitting 26 to be locked, and the sleeve metal fitting 28 and the insert metal fitting 26 are axially moved. Fixed to.
At the same time, the annular protrusion 40 of the sleeve fitting 28 penetrates through the cover rubber layer 20 of the hose 10 to reach the wire reinforcing layer 18, and their respective leading end portions bite into the wire reinforcing layer 18. The part 24 and the sleeve fitting 28 are fixed to the end of the hose 10 so that the end of the hose 10 is sandwiched from both the inside and outside.

In the present embodiment, when the sleeve fitting 28 is caulked in the diameter reducing direction, the cover presser 46 presses the cover rubber layer 20 inward in the radial direction by the pressing surface 48 of the inner peripheral surface thereof, and the cover presser in the hose 10 is pressed. The inner portion of 46 is restrained in the radial direction.
At this time, a part of the inner rubber layer 12 enters the annular groove 52 on the outer peripheral surface of the nipple portion 24 with elastic deformation by the pressing action of the cover presser 46.
Then, a part of the inner rubber layer 12 that has entered the annular groove 52 is physically engaged with the annular groove 52 in the axial direction, and the inner rubber layer 12 restrains the nipple portion 24 in the axial direction. receive.

In this embodiment, the cover presser 46 is in a reduced diameter state, that is, in a caulking state, and the cover rubber layer 20 is held at a pressing rate of 30% or more of its wall thickness at the start end of the pressing surface 48, that is, the root position of the annular protrusion 40 at the final position. Hold down. As such, the shape of the cover retainer 46 is determined.
However, the cover retainer 46 is positioned so that the position directly above the annular groove 52 in FIG. 1 (B), that is, the position facing the annular groove 52 in the radial direction, is 30% or more at the reference position. The presser foot rate may be set to
However, in this embodiment, the entire pressing surface 48 presses the end of the hose 10 in the radial direction with a pressing rate of 30% or more.

  In the connection structure of the hose fitting 22 according to this embodiment, the inner rubber layer 12 is physically engaged by the inner rubber layer 12 and the annular groove 52 which enter the annular groove 52 of the nipple portion 24 with elastic deformation. Is restrained in the axial direction, and the inner rubber layer 12 and the lower yarn layer 14 applied to the outer peripheral surface thereof are axially moved along with the axial extension of the sleeve fitting 28 when the sleeve fitting 28 is caulked. When the hose 10 pulsates, the inner rubber layer 12, more specifically, the inner rubber layer 12 sandwiched between the nipple portion 24 of the insert fitting 26 and the sleeve fitting 28 pulsates in the axial direction. Is suppressed.

Further, the end portion of the hose 10, specifically, the portion sandwiched between the cover presser 46 and the nipple portion 24 in the radial direction is suppressed in the radial direction by the pressing of the cover presser 46 inward in the radial direction and the restraining action.
As a result, the occurrence of large strain and stress concentration are suppressed locally, thereby effectively improving the durable life of the hose 10.

  A part of the inner rubber layer 12 that has entered the annular groove 52 suppresses the axial pulsation of the inner rubber layer 12 by an axial physical engagement force with the annular groove 52, and the pulsation of the hose 10 itself. Accordingly, there is also a function of absorbing or blocking vibration that has propagated to the same portion, which contributes to improving the durability of the hose 10.

The hose fitting shown in FIG. 5 and FIG. 6 was connected to the hose 10 to perform a durability test.
Here No.1 hose fittings in FIG. 5 (b) is a dimension _{L 2} of the caulking previous sleeve component 28 is 35 mm, those dimensions _{L 1} is 42mm in the insert fitting 26.
The sleeve metal fitting 28 is provided with a cover presser 46. The cover presser 46 has a pressing surface 48 parallel to the axial direction, and a step a with respect to the bottom surface of the annular groove 42 is 0.25 mm.

No.2 hose fittings in FIG. 5 (b) is a dimension _{L 2} is 40mm in sleeve component 28 relative to the No.1 of the hose fitting, the dimension _{L 1} is 50mm insert fitting 26, both No. The configuration is basically the same as that of No. 1 except that the length is longer than that of No. 1.
In both No. 1 and No. 2, no annular groove is provided in the nipple portion 24 of the insert fitting 26.

Hose fittings No.3 shown in (c) of FIG. 6, the dimensions _{L 2} is 40mm in sleeve component 28, is in 50mm dimension _{L 1} of the insert metal fitting 26, No.2 hose shown in FIGS. 5 (b) It is the same as the metal fitting, and the structure of the cover presser 46 is the same as that of No.2.
However, in the No. 3 hose fitting, an annular groove 52 similar to that shown in FIG. 1 is provided in the nipple portion 24 of the insert fitting 26.

No.4 hose fitting of FIG. 6 (d), the dimensions _{L 2} is 40mm in sleeve component 28, is in 50mm dimension _{L 1} of the insert metal fitting 26, No.2, similar in this respect and hose fittings No.3 It is.

Similar to the No. 3 insert fitting 26, an annular groove 52 similar to that shown in FIG.
Further, in this No. 4 hose fitting, a cover retainer 46 having the same shape and size as shown in FIG.

  The durability test and durability evaluation conform to the JIS-B-8360 impact pressure test.

The results are shown in Table 1.
The tightening rate shown in this table indicates the degree of caulking. Specifically, when the sleeve fitting 28 is caulked to the hose 10, the inner rubber compressed in the radial direction by the annular protrusion 40 of the sleeve fitting 28. This is the compression ratio of the layer 12 and the intermediate rubber layer 16.

  As shown in the results of Table 1, the durability of No. 2 is higher than that of No. 1 at a fastening rate of 45%. This is because the length of the nipple portion 24 is increased.

Next, No. 3 is obtained by adding an annular groove 52 to the nipple portion 24 of the insert fitting 26, and as a result, the durability is remarkably enhanced.
On the other hand, No. 4 having a higher press rate by the cover presser 46 has dramatically increased durability under any tightening rate with respect to the sleeve fitting 28.

  From these results, by providing the annular groove 52 on the outer peripheral surface of the nipple portion 24 in the insert metal fitting 26, and providing the cover presser 46 on the sleeve metal fitting 28, and further increasing the presser rate by the cover presser 46, It can be seen that the durability is effectively increased.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, the present invention is particularly effective when applied to a connecting structure using a small-diameter hose fitting whose inner diameter is 25 mm or less, but a structure for fixing a hose fitting of various other sizes and shapes to the hose. The present invention can be applied in various forms without departing from the gist of the present invention.

The hose metal fitting connection structure of one Embodiment of this invention is shown in the metal fitting connection state. It is the figure which showed the hose metal fitting of FIG. 1 in the state before a connection. It is the figure which expanded and showed the principal part of FIG. It is the figure which showed the procedure of the connection of the connection structure in the embodiment. It is the figure which showed the metal fitting used for the Example. It is the figure which showed the metal fitting different from FIG. 5 used for the Example. It is the figure which showed the example of the connection structure of the conventional skive system. It is the figure which showed the example of the conventional connection structure of a non skive system.

Explanation of symbols

10 Hose (high pressure rubber hose)
12 Inner rubber layer 14 Lower yarn layer 18 Wire reinforcing layer 20 Cover rubber layer 22 Hose fitting 24 Nipple part 26 Insert fitting 28 Sleeve fitting 40 Annular protrusion 42, 52 Annular groove 46 Cover presser

Claims (2)

An insert fitting provided with a nipple portion for a high-pressure rubber hose having a laminated structure of an inner rubber layer, a wire reinforcing layer, a cover rubber layer, and a lower yarn layer provided on the outer peripheral surface of the inner rubber layer; A hose fitting having a plurality of annular projections spaced apart in the axial direction and a sleeve fitting having an annular groove between the annular projections on the inner peripheral side thereof, In the connection structure of the hose metal fitting, the annular protrusion penetrates the cover rubber layer and bites into the wire reinforcing layer, and the rubber hose end is fixed between the inner and outer sides by the sleeve metal fitting and the insert metal fitting.
The sleeve fitting is provided with a cover presser that presses the cover rubber layer radially inward in a crimped state at a further rear portion of the annular projection at the rearward position in the axial direction away from the hose front end. An annular groove is provided on the outer peripheral surface of the nipple portion of the metal fitting and at a position facing the cover presser in the radial direction so that the inner rubber layer at the end of the rubber hose pressed by the cover presser enters, Hose fitting connection structure characterized in that a portion of the rubber hose end portion sandwiched between the cover retainer and the nipple portion is restrained in the radial direction and the axial direction by the cover retainer and the annular groove .   The hose fitting connection structure according to claim 1, wherein the cover presser has an inner peripheral pressing surface positioned radially inward from a groove bottom surface of the annular groove.

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