Hydraulic coupling device

Abstract

The hydraulic coupling device comprises an inner sleeve 12 having a conical outer surface 12b, an outer sleeve 14 having a conical inner surface 14a mounted on the conical outer surface 12b of the inner sleeve, and a nut 16 screwed onto the inner sleeve 12. The device further comprises a cylinder 18, which is manufactured separately from and attached to the outer sleeve 14, the nut 16 engaging at least partially in the cylinder 18. The inner sleeve 12, the cylinder 18, the nut 16, and the outer sleeve 14 together define a chamber 22. The cylinder 18 has a front face 18d bearing axially against a front face 14c of the outer sleeve. At least one of the front faces 14c, 18d of the cylinder and the outer sleeve is provided with a coating 23 having a coefficient of friction greater than that of said front face. Reference: Figure 1.

Description

Title of the invention: Hydraulic coupling device Technical field of the invention

[0001] The present invention relates to the field of hydraulic coupling devices, in particular used to create a simple connection between two shafts. Prior art

[0002] Conventionally, a hydraulic coupling device comprises a thin inner sleeve and a thick outer sleeve. The outer surface of the inner sleeve is slightly tapered, and the bore of the outer sleeve has a corresponding taper. The bore of the inner sleeve is slightly larger than the diameter of the shafts to be connected, so as to allow the inner sleeve to pass easily over them.

[0003] The hydraulic coupling device further comprises a piston or nut screwed onto the inner sleeve and, together with the inner and outer sleeves, defining a hydraulic chamber intended to be filled with oil or a similar fluid. A sealing gasket is placed on the nut to prevent oil from escaping from the chamber between the nut and the inner and outer sleeves.

[0004] The coupling device is mounted by fitting the outer sleeve onto the taper of the inner sleeve using oil pumped into the hydraulic chamber. This compresses the inner sleeve onto the shafts, creating a tight fit. When the outer sleeve reaches the correct fitting position, the injection pressure is released and the oil connection is plugged.

[0005] The fitting operation results in radial expansion of the outer sleeve. This affects the initial radial clearance between the outer diameter of the nut and the outer sleeve. There is also a risk of tilting of the sealing gasket on the nut, which could lead to oil leakage.

[0006] Furthermore, the outer surface of the outer sleeve may be provided with a radial flange for attaching a brake disc, creating a braking function or using a drive unit. The outer surface of the radial flange may also be provided with teeth or another mechanical component.

[0007] The final machining of such external components must be done with the hydraulic coupling device in the mounted position by means of a false shaft.

[0008] One object of the present invention is to remedy these drawbacks. Summary of the invention

[0009] The invention relates to a hydraulic coupling device comprising an inner sleeve having a conical outer surface, an outer sleeve provided with a conical inner surface mounted on the conical outer surface of the inner sleeve, and a nut screwed onto the inner sleeve.

[0010] According to a general feature, the device further comprises a cylinder which is manufactured separately from the outer sleeve and attached to it, the nut engaging at least partially in the cylinder. The inner sleeve, the cylinder, the nut, and the outer sleeve together define a chamber.

[0011] According to another general characteristic, the cylinder is provided with a front face that comes into axial contact against a front face of the outer sleeve.

[0012] In a first embodiment, at least one of these front faces is provided with a coating having a coefficient of friction greater than that of said front face.

[0013] In a second embodiment, at least one of the front faces of the cylinder and outer sleeve includes at least one protrusion engaging in a complementary recess formed on the other front face.

[0014] In a third embodiment, at least one of the front faces of the cylinder and outer sleeve is provided with a coating having a coefficient of friction greater than that of said front face, and at least one of these front faces includes at least one protrusion engaging in a complementary recess provided on the other front face.

[0015] Thanks to this design, the cylinder is less affected by the radial expansion of the outer sleeve during the fitting operation.

[0016] Furthermore, thanks to the coating and / or the permanent mechanical clutch between the cylinder and the outer sleeve, the connection between these two parts offers a torque transmission capacity equivalent to, or close to, that of the conventional hydraulic coupling device.

[0017] If necessary, the final machining of the cylinder can be done before mounting the hydraulic coupling device and therefore without requiring a false shaft.

[0018] By way of example, the coefficient of friction of said coating may be at least equal to 0.3 and preferably at least equal to 0.45.

[0019] Thanks to this design, it is also possible to use different materials for the cylinder and the outer sleeve, for example, materials with different material properties. Alternatively, the cylinder and the outer sleeve can be formed from the same material but have different mechanical properties. For example, the mechanical properties can vary depending on the dimensions and the heat treatment.

[0020] The cylinder may project radially outwards from the outer surface of the outer sleeve, for example if the cylinder includes external components, such as a flange or teeth. Alternatively, it would be possible to provide that the cylinder is either radially offset inwards relative to the outer surface of the outer sleeve, or is at the same level as this outer surface.

[0021] In one embodiment, the nut comprises a main part and a nose having a reduced diameter and projecting axially towards the outer sleeve.

[0022] Preferably, the device includes a first sealing gasket interposed radially between the inner sleeve and the nose of the nut, and a second sealing gasket interposed radially between the cylinder and the nose.

[0023] Alternatively, it would be possible to have a single sealing gasket placed on the nut and having an inner edge in contact with the inner sleeve and an outer edge in contact with the cylinder. In this case, the nut may not have a nose. This sealing gasket could be attached to a front face of the nut aligned axially with the outer sleeve.

[0024] The device may further include at least one sealing gasket placed axially between the outer sleeve and the cylinder.

[0025] Advantageously, the chamber is defined radially between the conical outer surface of the inner sleeve and the bore of the cylinder. The chamber can be defined axially between the nut and the outer sleeve.

[0026] Preferably, the outer sleeve, or the cylinder, or the nut, may be provided with at least one injection channel formed in its thickness and opening into the chamber.

[0027] Brief description of the figures

[0028] The present invention and its advantages will be better understood upon reading the detailed description of particular embodiments given by way of non-limiting examples and illustrated by the accompanying drawing in which:

[0029] Figure 1 shows a partial cross-section of a hydraulic coupling device according to a first embodiment of the invention, and

[0030] [Fig.2] represents a partial cross-section of a hydraulic coupling device according to a second embodiment of the invention. Detailed description of the invention

[0031] The hydraulic coupling device 10 illustrated in [Fig.1] comprises an annular inner sleeve 12, an annular outer sleeve 14 mounted on the inner sleeve and an annular piston or nut 16 screwed onto the inner sleeve.

[0032] As will be described later, the device 10 further comprises an annular cylinder 18 which is manufactured separately from the outer sleeve 14 and which is attached to it.

[0033] The inner sleeve 12 comprises a cylindrical inner surface or a bore 12a and a conical outer surface 12b which is radially opposite the bore 12a. The inner sleeve also has an axial end with an external thread 12c extending radially outwards. In the illustrated example, the external thread 12c is radially offset inwards relative to the conical outer surface 12b.

[0034] The outer sleeve 14 comprises a conical inner surface 14a conforming to the conical outer surface 12b of the inner sleeve and mounted on this conical outer surface. The outer sleeve 14 also comprises an outer surface 14b which is radially opposite the conical inner surface 14a. The outer sleeve 14 further comprises two opposing first and second front faces 14c, 14d which axially delimit the conical inner surface 14a and the outer surface 14b.

[0035] As mentioned above, the cylinder 18 is manufactured separately from the outer sleeve 14. The cylinder 18 radially surrounds the inner sleeve 12. The cylinder 18 radially surrounds the conical outer surface 12b of the inner sleeve left free by the outer sleeve 14. The cylinder 18 also partially radially surrounds the nut 16. The cylinder 18 projects radially from the front face 14c of the outer sleeve. The cylinder 18 projects radially from the outer surface 14b of the outer sleeve. The nut 16 is partially engaged in the cylinder 18. Alternatively, the nut 16 can be fully engaged in the cylinder 18. A slight radial clearance is provided between the nut 16 and the cylinder 18.

[0036] The cylinder 18 is mounted axially against the front face 14c of the outer sleeve. The cylinder 18 is secured to the outer sleeve 14. In the illustrated example, the device 10 includes a plurality of fastening screws 20 for securing the cylinder 18 to the outer sleeve 14. The screws 20 are spaced circumferentially, preferably at regular intervals. The screws 20 extend axially through the cylinder 18. Each screw 20 engages within a tapped hole (not shown) provided from the front face 14c of the outer sleeve.

[0037] The cylinder 18 comprises an inner cylindrical surface or bore 18a and an outer surface 18b which is radially opposite the bore 18a. The outer surface 18b is radially offset outwards relative to the outer surface 14b of the outer sleeve.

[0038] The cylinder 18 also includes two opposing first and second front surfaces 18c, 18d which axially delimit the bore 18a and the outer surface 18b. The front face 18d comes into axial contact with the front face 14c of the outer sleeve.

[0039] As will be described later, a high-friction coating 23 is applied to the front face 18d of the cylinder. The coating 23 has a coefficient of friction greater than that of the 18d front face.

[0040] The nut 16 also includes a cylindrical inner surface or bore 16a and a cylindrical outer surface 16b which is radially opposite the bore 16a. The nut 16 further includes two opposing first and second front faces 16c, 16d which axially delimit the bore 16a and the outer surface 16b.

[0041] As mentioned above, a slight radial clearance is provided between the nut 16 and the cylinder 18. This radial clearance is provided between the outer surface 16b of the nut and the bore 18a of the cylinder. The bore 16a of the nut is provided with an internal thread 16e which engages with the external thread 12c of the inner sleeve.

[0042] The nut 16, the outer sleeve 14, the inner sleeve 12, and the cylinder 18 together define an annular hydraulic chamber 22. The chamber 22 is axially defined by the nut 16 and the outer sleeve 14. More precisely, the chamber 22 is axially defined by the front face 16d of the nut and the front face 14c of the outer sleeve. The chamber 22 is radially defined by the inner sleeve 12 and the cylinder 18. More precisely, the chamber 22 is radially defined by the bore 18a of the cylinder and the conical outer surface 12b of the inner sleeve.

[0043] The chamber 22 is intended to be filled with oil or a similar liquid. For this purpose, an injection channel 24 is provided in the thickness of the outer sleeve 14. One end of the injection channel 24 opens into the chamber 22. The injection channel 24 opens onto the front face 14c of the outer sleeve. An injection hole 26 is provided on the outer surface 14b of the outer sleeve and is connected to a second end of the injection channel 24, which is opposite the first end. Alternatively, the injection channel 24 and the injection hole 26 may be provided on the nut 16 or on the piston 18.

[0044] The outer sleeve 14 is also provided with additional injection channels (not shown) to allow the formation of an oil film between the outer and inner conical surfaces 12b, 14a of the inner and outer sleeves.

[0045] In the illustrated example, the nut 16 comprises a main portion 28 and a nose 30 having a reduced outer diameter and projecting axially towards the outer sleeve 14. In the illustrated example, the main portion 28 and the nose 30 are manufactured as a single unit. Alternatively, the nose 30 can be manufactured separately from the main portion 28. The main portion 28 of the nut defines the bore 16a, the outer surface 16b, and the front face 16c. The nose 30 defines the front face 16d.

[0046] The device 10 further comprises a first annular sealing gasket 32 ​​radially interposed between the outer surface 12b of the inner sleeve and the nose 30 of the nut, and a second sealing gasket 34 radially interposed between the bore 18a of the cylinder and the nose. The sealing gasket 32 ​​makes radial contact with the nut 30 and the outer surface 12b of the inner sleeve. The sealing gasket 32 ​​can The sealing ring 34 comes into contact with a cylindrical or conical portion of the outer surface 12b. It is in radial contact with the nut 30 and the bore 18a of the cylinder. The sealing rings 32 and 34 do not protrude beyond the front face 16d of the nut. In the example shown, the sealing rings 32 and 34 have a circular cross-section. Alternatively, the sealing rings 32 and 34 may have other shapes.

[0047] The device 10 further includes an additional sealing gasket 36 placed radially between the outer sleeve 14 and the cylinder 18. The sealing gasket 36 is placed axially between the front face 14c of the outer sleeve and the front face 18d of the cylinder.

[0048] The sealing gaskets 32 to 36 are placed in order to prevent oil from escaping from chamber 22 respectively between the nut 16 and the inner sleeve 12, the nut and the cylinder 18, and between the cylinder and the outer sleeve 14.

[0049] As mentioned above, the coating 23 is applied to the front face 18d of the cylinder. The coating 23 has a higher coefficient of friction than the front face 18d. The coating 23 can be sprayed onto the front face 18d. In the illustrated example, the coating 23 partially covers the front face 18d. The coating 23 covers only the portion of this front face that is in axial contact with the front face 14c of the outer sleeve. The coating 23 is in axial contact with the front face 14c. Alternatively, the coating 23 can cover the entire front face 18d of the cylinder.

[0050] The coefficient of friction of the coating 23 is at least 0.3 and preferably at least 0.45. By way of example, the coefficient of friction may be between 0.3 and 0.6. The hardness of the coating 23 may be at least 700 HV. By way of example, the surface roughness of the coating 23 is between 3 micrometers and 4 micrometers. The thickness of the coating 23 is between 0.02 mm and 0.04 mm. In one embodiment, the coating 23 may be a tungsten carbide coating. Alternatively, other coatings that increase friction may be used. The coating may be applied using plasma spraying technology.

[0051] In this example, the coating 23 is applied to the front face 18d of the cylinder. Alternatively, the coating 23 can be applied to the front face 14c of the outer sleeve. The coating 23 can cover the entire front face 14c or can cover only the portion of this front face that is in axial contact with the front face 18d of the cylinder. In such an embodiment, the coating 23 is in axial contact with the front face 18d of the cylinder.

[0052] Alternatively, the coating can also be applied to both the front face 18d of the cylinder and the front face 14c of the outer sleeve. In this case, the re- the garments come into axial contact with each other.

[0053] The example shown in [Fig.2], where identical components bear identical references, differs from the previous example in that the front face 18d of the cylinder includes a plurality of protrusions 40 which project into recesses 42 of complementary shape provided on the front face 14c of the outer sleeve.

[0054] The protrusions 40 are spaced circumferentially, preferably at regular intervals. Each protrusion 40 extends axially. Each protrusion 40 engages in one of the recesses 42 of complementary shape. In the illustrated example, the protrusions 40 are formed as a single unit with the cylinder. The shape of each recess 42 formed on the front face 14c of the outer sleeve is complementary to that of the associated protrusion 40 of the cylinder. Each recess 42 extends axially inward from the front face 14c.

[0055] Each protrusion 40 formed on the cylinder is located inside the associated recess 42 formed on the outer sleeve. Each protrusion 40 fits completely into the associated recess 42. The protrusions 40 and the recesses 42 form a permanent mechanical clutch that couples the cylinder 18 and the outer sleeve 14 by an interference fit.

[0056] In the illustrated example, the protrusions 40 are formed on the front face 18d of the cylinder and the recesses 42 are formed on the front face 14c of the outer sleeve. Alternatively, an inverted arrangement is possible where the protrusions 40 are formed on the front face 14c of the outer sleeve and the recesses 42 are formed on the front face 18d of the cylinder. In another embodiment, protrusions may be formed on both the front face 18d and the front face 14c, and each protrudes into a recess formed on the front face 14c or on the front face 18d.

[0057] In another embodiment, it might be possible to provide protrusions on the front face 18d of the cylinder and / or on the front face 14c of the outer sleeve together with the coating as described above which covers at least one of these front faces.

Claims

Demands

1. A hydraulic coupling device comprising an inner sleeve (12) having a conical outer surface (12b), an outer sleeve (14) having a conical inner surface (14a) mounted on the conical outer surface (12b) of the inner sleeve, and a nut (16) screwed onto the inner sleeve (12), the device being characterized in that it further comprises a cylinder (18) which is manufactured separately from the outer sleeve (14) and which is attached to it, the cylinder (18) having a front face (18d) bearing axially against a front face (14c) of the outer sleeve, the nut (16) engaging at least partially in the cylinder (18), in that the inner sleeve (12), the cylinder (18), the nut (16) and the outer sleeve (14) together define a chamber (22), and in that at least one of the front faces (14c,18d) of the cylinder and outer sleeve is provided with a coating (23) having a coefficient of friction greater than that of said front face, and / or at least one of these front faces (14c, 18d) includes at least one protrusion (40) engaging in a complementary recess (42) formed on the other front face.

2. Device according to claim 1, wherein the coefficient of friction of said coating is at least equal to 0.3 and, preferably, at least equal to 0.

45.

3. Device according to claim 1 or 2, wherein the cylinder (18) is made of a material different from the material of the outer sleeve (14).

4. Device according to any one of the preceding claims, wherein the cylinder (18) projects radially outwards from the outer surface (14b) of the outer sleeve.

5. Device according to any one of the preceding claims, wherein the nut (16) comprises a main part (28) and a nose (30) having a reduced outside diameter and projecting axially towards the outer sleeve (14).

6. Device according to claim 5, further comprising a first sealing gasket (32) interposed radially between the inner sleeve (12) and the nose (30) of the nut, and a second sealing gasket (34) interposed radially between the cylinder (18) and the nose.

7. A device according to any one of the preceding claims, further comprising at least one sealing gasket (36) placed axially between the outer sleeve (14) and the cylinder (18).

8. Device according to any one of the preceding claims, wherein the chamber (22) is defined radially between the conical outer surface (12b) of the inner sleeve and the bore (18a) of the cylinder.

9. Device according to any one of the preceding claims, wherein the chamber (22) is defined axially between the nut (16) and the outer sleeve (14).

10. Device according to any one of the preceding claims, wherein the outer sleeve (14) is provided with at least one injection conduit (24) formed in its thickness and opening into the chamber (22).

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