CN213478988U - Rotary damper - Google Patents

Abstract

A rotary damper comprising: a housing comprising a radially inner wall, a radially outer wall and an end wall delimiting a chamber containing a viscous brake fluid, and a rotor rotatably connected to the housing and mounted on the housing on the opposite side with respect to the end wall so as to close the chamber, the rotor comprising a braking portion in the shape of an annular collar extending axially inside the chamber and interposed between the radially inner and outer walls of the housing, characterized in that a plurality of grooves extending axially along the braking portion of the rotor are formed on the braking portion, the plurality of grooves comprising a first groove and a second groove, wherein each of the first grooves has a respective through opening extending radially through the braking portion, and wherein the second groove is free of through openings. The rotary damper of the present disclosure avoids deterioration of braking performance by avoiding the formation of parallel fluid layers.

Description

Rotary damper

Technical Field

The utility model relates to a rotary damper, this type of rotary damper includes:

-a housing comprising a radially inner wall, a radially outer wall and an end wall delimiting a chamber containing a viscous brake fluid; and

-a rotor rotatably connected to the housing and mounted on the housing on the opposite side with respect to the end wall so as to close the chamber, the rotor comprising a braking portion having the shape of an annular collar extending axially inside the chamber and interposed between a radially inner wall and a radially outer wall of the housing.

Background

A device of this type is known, for example, from german utility model DE 29604260U 1, which describes a tilting handle provided with a hand grip hinged to a mounting wall of the vehicle. The hand grip is rotatable against the action of the resilient means from the rest position to the operating position when abutting the mounting wall. After being released by the user, the hand grip automatically returns from the operating position to the rest position. The return movement to the rest position is made softer by a braking device of the type defined above acting on the axis of rotation of the handle.

It has been found that the braking performance of this type of damper may show a lack of uniformity over time. It has in fact been noted that in the condition of repeated use, the braking torque tends to decrease from an initial value to a given stable value. The length of the rest interval between successive uses seems to influence this reduced strength.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide a rotary damper of compact size which allows to overcome the above mentioned problems.

This object is achieved by a rotary damper as defined according to the invention of the above-mentioned type, wherein a plurality of grooves are formed on the braking portion of the rotor, which grooves extend axially along the braking portion of the rotor, said plurality of grooves comprising a first groove and a second groove, wherein a through-opening extending radially through the braking portion is formed in each of said first grooves, and wherein said second groove is free of through-openings.

In such a damper, the grooves and the through openings formed on the braking portion of the rotor cause turbulence in the fluid between the braking portion of the rotor and the wall of the housing. In conventional dampers, the deterioration of the braking performance appears to be actually linked to the formation of parallel fluid layers between the braking portion of the rotor and the wall of the housing, which results in a significant reduction in the viscous friction experienced by the braking portion of the rotor. Deterioration of braking performance is avoided by avoiding the formation of such parallel fluid layers.

The present disclosure provides a rotary damper, the rotary damper comprising: a housing including a radially inner wall, a radially outer wall, and an end wall defining a chamber containing a viscous brake fluid; and a rotor rotatably connected to the housing and mounted on the housing on an opposite side with respect to the end wall so as to close the chamber, the rotor comprising a braking portion having the shape of an annular collar, the braking portion extending axially inside the chamber and being interposed between a radially inner wall and a radially outer wall of the housing, wherein a plurality of grooves extending axially along the braking portion of the rotor are formed on the braking portion, the plurality of grooves comprising a first groove and a second groove, wherein each of the first grooves has a respective through opening extending radially through the braking portion, and wherein the second groove is free of through openings.

The brake portion is a first brake portion, and the rotor includes a second brake portion having the shape of an annular collar, the second brake portion extending axially inside the chamber and interposed between the radially inner wall of the housing and the first brake portion.

The second brake portion has a plurality of through openings formed therein that extend radially therethrough, each through opening of the second brake portion facing a respective one of the through openings of the first brake portion.

The housing further comprises a radial intermediate wall interposed between the first and second braking portions of the rotor.

A plurality of slots extending axially along the intermediate radial wall of the housing are formed in the intermediate radial wall of the housing.

A plurality of third grooves extending axially along the radially inner wall of the housing are formed on the radially inner wall of the housing, each of the third grooves of the radially inner wall facing a corresponding one of the slots of the radially intermediate wall of the housing.

The housing is made in one piece and comprises a rim which is rolled up on the rotor to axially retain the rotor.

The viscous brake fluid is a polyester oil.

The rotary damper of the present disclosure avoids deterioration of braking performance by avoiding the formation of parallel fluid layers.

Drawings

Further features and advantages of the device according to the invention will become clearer from the following detailed description of embodiments of the invention, provided for purely illustrative and non-limiting purposes, with reference to the accompanying drawings, in which:

figure 1 is an exploded view of a rotary damper according to the invention;

figure 2 is a side view of the damper of figure 1;

figure 3 is a sectional view taken along the line III-III of figure 2;

figures 4 and 5 are cross-sectional views taken along the lines IV-IV and V-V of figure 3, respectively;

figure 6 is a side view of the rotor of the rotary damper;

figures 7 to 9 are cross-sectional views taken along the lines VII-VII, VIII-VIII and IX-IX, respectively, of figure 6;

figure 10 is a side view of the housing for the rotary damper; and

fig. 11 and 12 are sectional views taken along lines XI-XI, XII-XII in fig. 10, respectively.

Detailed Description

The drawings show a barrel-type rotational damper, generally designated 10.

The damper 10 comprises a housing 12 made of a plastic material on which a rotor 14 made of a plastic material is rotatably mounted about an axis. The housing 12 is substantially cylindrical and has a through central opening 15 which allows the damper to be mounted on the axis of rotation of the movable member according to the arrangement described in utility model DE 29604260U 1. There may be no central opening 15 depending on how the damper 10 is installed.

As can be seen in particular in fig. 11 and 12, the casing 12 is an element made in a single piece and defines an annular chamber 16 coaxial with the central opening 15, which contains a viscous fluid, for example a Polyester Oil (POE). It is possible to use another fluid in common in this section. The chamber 16 is laterally delimited by a radially inner wall 17 and a radially outer wall 18 and is closed at one end by an end wall 19. The housing 12 also comprises a radially intermediate wall 20 extending axially from the end wall 19 inside the chamber 16 and located between the radially inner wall 17 and the radially outer wall 18.

On the radially outer surface of the radially outer wall 18 there may be a first tab 18c configured to rotate the housing 12 integrally with one of the torque elements, the relative rotational movement of which must be slowed by the damper 10. The first tab 18c may be replaced by an alternative arrangement having the same function.

The end of the chamber 16 opposite the end wall 19 is open and the radially outer wall 18 has a rim 18a at that end. In assembly, once the rotor 14 has been positioned inside the housing 12, the edge 18a is folded inwardly, for example by heat or ultrasonic impact. In a position adjacent to the edge 18a, a shoulder 18b is formed on the inner surface of the radially outer wall 18.

With this arrangement, the housing 12 holds the rotor 14 axially so that the housing can enclose the chamber 16. In practice, the rotor 14 has a flange 14a formed on the radially outer surface thereof, intended to be axially engaged between the shoulder 18b and the folded edge 18a of the casing 12.

The hermetic sealing of the chamber 16 is ensured by a first O-ring 21 and a second O-ring 22. A first O-ring 21 is housed in a corresponding first seat 23 formed on the radially inner wall 17 of the casing 12 and is interposed between the radially inner wall 17 and the radially inner surface of the rotor 14, so as to provide a radial seal. A second O-ring 22 is housed in a corresponding second seat 24 formed on the radially outer surface of the rotor 14 and interposed between this radially outer surface and the radially outer wall 18 of the casing 12, so as to provide a radial seal.

A second tab 14b may be formed on the axially outer surface of the rotor 14 that is configured such that the rotor 14 rotates integrally with the other of the torque elements, the relative rotational movement of which must be slowed by the damper 10. In addition to the second tab 14b, there may be alternative means of the same function.

The alignment and centering of the rotor 14 relative to the chamber 16 of the housing 12 is ensured by a radially inner wall 17 and a radially outer wall 18 of the housing 12. In particular, a radially inner wall 17 of the casing 12 defines a rotation pin of the rotor 14. A through hole 25 is formed in the rotor 14 and is intended to coaxially receive one of the members to which the damper 10 is connected. The through hole 25 has a section 26 with an enlarged diameter and intended to receive the radially inner wall 17 of the housing 12 to function as a rotation pin.

The rotor 14 also comprises a first stop portion 27 having the shape of an annular collar, which extends axially inside the chamber 16 and is interposed between the radially inner wall 17 and the radially outer wall 18 of the casing 12. The rotor 14 may also comprise a second braking portion 28 having the shape of an annular collar, which extends axially inside the chamber 16 and is interposed between the radially inner wall 17 of the casing 12 and the first braking portion 27. The first and second braking portions 27, 28 are in one piece with the rotor 14.

As can be further seen in fig. 3 to 5, the radially intermediate wall 20 of the housing 12 is interposed between the first and second stop portions 27, 28. Accordingly, respective gaps, each filled with a viscous fluid therein, are defined between the radially inner wall 17 and the second brake portion 28, between the second brake portion 28 and the radially intermediate wall 20, between the radially intermediate wall 20 and the first brake portion 27, and between the first brake portion 27 and the radially outer wall 18.

Viscous friction associated with movement of the first and second braking portions 27, 28 of the rotor 14 in the chamber 16 causes the damper 10 to provide a braking action during rotation of the rotor 14 relative to the housing 12.

First and second grooves 33', 33 "(see in particular fig. 8 and 9) extending axially along the first detent portion 27 and arranged evenly spaced apart in the circumferential direction are formed on the first detent portion 27 of the rotor 14, more precisely on the side thereof facing the radially outer wall 18 of the housing 12. In particular, the array of first grooves 33 'and the array of second grooves 33 "are arranged preferably alternately in a regular pattern (for example, every second groove 33" has one first groove 33', or, as in the example shown, every third second groove 33 ". At each of the first grooves 33', there is formed a through opening 36 extending radially through the first detent portion 27. The second groove 33 "has no through opening; in other words, the second grooves 33 "are not through-going along their entire length.

The first and second grooves 33', 33 "interrupt the annular profile of the first stop portion 27 and are therefore adapted to induce turbulence in the fluid inside the chamber 16. This prevents the formation of parallel fluid layers in the vicinity of the first braking portion 27, thus maintaining uniformity over time of the braking effectiveness of the damper.

Preferably, to further improve the braking performance of the damper, a plurality of through openings 38 are formed in the second brake portion 28 extending radially through the second portion 28. Each of the through openings 38 of the second detent portion 28 faces a respective one of the through openings 36 of the first detent portion 27. This arrangement allows the through openings 36 and 38 to be easily made during the manufacturing process of the rotor, for example by injection moulding.

Preferably, in order to further improve the braking performance of the damper, a plurality of through slots 39 are formed on the radial intermediate wall 20 of the housing 12 to extend axially along the radial intermediate wall 20 of the housing 12 (specifically, see fig. 11 and 12). This performance is further increased if a plurality of third grooves 40 extending axially along the radially inner wall 17 of the housing 20 are formed on the radially inner wall 17 of the housing 12. Each of the third recesses 40 of the radially inner wall 17 faces a respective one of the slots 39 of the radially intermediate wall 20 of the housing 12. This arrangement allows the slot 39 and the third recess 40 to be easily formed during manufacture of the housing, for example by injection moulding.

Claims (10)

1. A rotary damper (10) comprising:

-a housing (12) comprising a radially inner wall (17), a radially outer wall (18) and an end wall (19) delimiting a chamber (16) containing a viscous brake fluid, and

-a rotor (14) rotatably connected to the casing and mounted thereon on the opposite side with respect to the end wall (19) so as to close the chamber (16), the rotor comprising a braking portion (27) having the shape of an annular collar extending axially inside the chamber (16) and interposed between the radially inner wall (17) and the radially outer wall (18) of the casing (12),

characterized in that a plurality of grooves extending axially along the braking portion (27) of the rotor (14) are formed on the braking portion (27), said plurality of grooves comprising a first groove and a second groove, wherein each of the first grooves (33') has a respective through opening extending radially through the braking portion (27), and wherein the second groove is free of through openings.

2. The rotary damper according to claim 1, characterized in that the braking portion is a first braking portion (27), the rotor comprising a second braking portion (28) having the shape of an annular collar, which extends axially inside the chamber (16) and is interposed between a radially inner wall (17) of the casing (12) and the first braking portion (27).

3. A rotary damper according to claim 2, characterized in that a plurality of through openings extending radially through the second detent portion (28) are formed on the second detent portion (28), each through opening of the second detent portion (28) facing a respective one of the through openings of the first detent portion (27).

4. A rotary damper according to claim 2 or 3, characterized in that the housing further comprises a radial intermediate wall (20) interposed between the first and second braking portions (27, 28) of the rotor (14).

5. A rotary damper according to claim 4, characterized in that a plurality of slots (39) extending axially along the radial intermediate wall (20) of the housing (12) are formed on the radial intermediate wall (20) of the housing (12).

6. A rotary damper according to claim 5, characterized in that a plurality of third grooves (40) extending axially along the radially inner wall (17) of the housing (12) are formed on the radially inner wall (17) of the housing (12), each third groove (40) of the radially inner wall (17) facing a respective one of the slots (39) of the radially intermediate wall (20) of the housing (12).

7. The rotary damper according to claim 1, characterized in that the housing is made in one piece and comprises a rim (18a) which is rolled up on the rotor (14) to axially retain the rotor.

8. The rotary damper according to claim 6, characterized in that the housing is made in one piece and comprises a rim (18a) which is rolled up on the rotor (14) to axially retain the rotor.

9. The rotary damper of claim 1, wherein the viscous brake fluid is a polyester oil.

10. The rotary damper of claim 8, wherein the viscous brake fluid is a polyester oil.

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