阅读说明：本技术 减振装置 (Vibration damping device ) 是由 肖荣亭 于 2020-12-15 设计创作，主要内容包括：本发明涉及减振装置。公开了一种减振装置,包括保持架、法兰、摩擦件和减振弹簧。法兰设置成相对于保持架能够沿周向在预定范围内转动；摩擦件设置成与保持架和法兰摩擦接合,其中摩擦件和法兰被分别施加轴向力,以使得保持架与摩擦件之间的摩擦力大于法兰与摩擦件之间的摩擦力,其中法兰包括弧形通孔,第一摩擦件包括伸出部,伸出部插入到弧形通孔中。在减振弹簧处于未压缩的初始状态下,伸出部的第一周向端部与弧形通孔的第一周向端部之间的圆弧对应的第一圆心角大于伸出部的第二周向端部与弧形通孔的第二周向端部之间的圆弧对应的第二圆心角,第一圆心角大于驱动侧最大旋转角度,第二圆心角小于滑行侧最大旋转角度。(The present invention relates to a vibration damping device. A damping device is disclosed, comprising a cage, a flange, a friction member and a damping spring. The flange is arranged to be rotatable in a circumferential direction within a predetermined range relative to the holder; the friction member is disposed in frictional engagement with the holder and the flange, wherein the friction member and the flange are respectively applied with an axial force such that a frictional force between the holder and the friction member is greater than a frictional force between the flange and the friction member, wherein the flange includes an arc-shaped through hole, and the first friction member includes a protruding portion inserted into the arc-shaped through hole. When the damping spring is in an uncompressed initial state, a first central angle corresponding to an arc between a first circumferential end of the extension portion and a first circumferential end of the arc through hole is larger than a second central angle corresponding to an arc between a second circumferential end of the extension portion and a second circumferential end of the arc through hole, the first central angle is larger than a maximum rotation angle of the driving side, and the second central angle is smaller than a maximum rotation angle of the sliding side.)

1. A vibration damping device comprising:

a holder;

a flange (30) provided so as to be rotatable in a circumferential direction within a predetermined range with respect to the holder;

a first friction member (50) disposed to be frictionally engaged with the cage and the flange (30), respectively, wherein the cage, the first friction member (50) and the flange (30) are arranged with a rotation axis, wherein the first friction member (50) and the flange (30) are respectively applied with an axial force such that a frictional force between the cage and the first friction member (50) is greater than a frictional force between the flange (30) and the first friction member (50) when the cage and the flange (30) relatively rotate, wherein the flange (30) includes an arc-shaped through hole (33) and the first friction member (50) includes a protruding portion (52), the protruding portion (52) of the first friction member (50) being inserted into the arc-shaped through hole (33) of the flange (30); and

at least one damping spring (40) mounted in a spring mounting formed by the cage, the flange (30) and the first friction member (50),

wherein the damping device is configured such that, in an initial state in which the damping spring (40) is uncompressed, a first central angle corresponding to an arc between a first circumferential end of the protrusion (52) and a corresponding first circumferential end of the arcuate through hole (33) is greater than a second central angle corresponding to an arc between a second circumferential end of the protrusion (52) and a corresponding second circumferential end of the arcuate through hole (33), the first central angle being greater than a driving-side maximum rotation angle of the damping device, and the second central angle being less than a sliding-side maximum rotation angle of the damping device.

2. The vibration damping device according to claim 1, wherein the cage comprises a first side plate (10) and a second side plate (20) which are connected to each other in a rotationally fixed manner, and the flange (30) is arranged between the first side plate (10) and the second side plate (20) in an axial direction of the vibration damping device, and

wherein the first friction member (50) further comprises a friction disc (51), the friction disc (51) being disposed between the first side plate (10) and the flange (30) in the axial direction, the friction disc (51) comprising a first surface and a second surface, the first surface of the friction disc (51) being in frictional engagement with the first side plate (10), the second surface of the friction disc (51) being in frictional engagement with the flange (30), and the protrusion (52) protruding from the second surface of the friction disc (51).

3. Damping device according to claim 2, wherein the friction disc (51) comprises a window (53) for mounting the damping spring (40), the length of the window (53) being larger than the length of the damping spring (40) in an initial state of non-compression.

4. The vibration damping device according to claim 3, further comprising a first elastic member (80) and a second elastic member (90), the first elastic member (80) being for applying an axial force to the first friction member (50), the second elastic member (90) being for applying an axial force to the flange (30).

5. The vibration damping device according to claim 4, wherein the first elastic member (80) is disposed between the second side plate (20) and the protruding portion (52) in the axial direction, and the second elastic member (90) is disposed between the second side plate (20) and the flange (30) in the axial direction.

6. The vibration damping device according to claim 5, further comprising a second friction member (60), the second friction member (60) being arranged in the axial direction between the protrusion (52) of the first friction member (50) and the second side plate (20) and being torsionally connected with the second side plate (20), the first resilient member (80) being arranged to apply an axial force to the second friction member (60) such that the second friction member (60) frictionally engages the first friction member (50).

7. The vibration damping device according to claim 6, further comprising a third friction member (70), the third friction member (70) being arranged between the flange (30) and the second side plate (20) in the axial direction and being torsionally connected with the second side plate (20), the second resilient member (90) being arranged to apply an axial force to the third friction member (70) such that the third friction member (70) frictionally engages the flange (30).

8. The vibration damping device according to any one of claims 1 to 7, wherein the flange (30) includes a plurality of the arc-shaped through holes (33), the first friction member (50) includes a plurality of the protruding portions (52), and the plurality of the arc-shaped through holes (33) are provided in one-to-one correspondence with the plurality of protruding portions (52).

9. The vibration damping device according to any one of claims 4 to 7, wherein the first elastic member (80) and the second elastic member (90) are each a diaphragm spring.

10. A vehicle comprising a vibration damping device according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of vibration reduction. More particularly, the present invention relates to a vibration damping device for a motor vehicle.

Background

A vibration damping device for a motor vehicle is generally installed between a crankshaft of an engine and an input shaft of a transmission for transmitting torque of the crankshaft of the engine to the input shaft of the transmission with effective damping of torsional vibration of the crankshaft of the engine, thereby reducing the influence of torsional vibration of the crankshaft of the engine on the transmission. In prior art damping devices comprising a hub flange, the hub flange is axially constrained by annular friction members and diaphragm springs. Such a damping device has the same hysteresis effect in the driving state and in the coasting state of the engine, and therefore a two-stage hysteresis cannot be achieved by a single hub flange. However, a damper device for a hybrid-dedicated transmission is expected to have a smaller hysteresis in a driving state and a larger hysteresis in a coasting state under some conditions.

For this reason, a damper device capable of having different hysteresis effects in a driving state and a coasting state is required.

Disclosure of Invention

It is an object of the present invention to provide a vibration damping device having different hysteresis effects in a driving state and a coasting state. It is another object of the present invention to provide a vibration damping device capable of generating two-stage damping in a coasting state. Another object of the present invention is to provide a damping device having a better torsional damping effect, particularly in a coasting situation.

One aspect of the present invention provides a vibration damping device including: a holder; a flange provided to be rotatable in a circumferential direction within a predetermined range with respect to the holder; a first friction member disposed to be frictionally engaged with the holder and the flange, respectively, wherein the holder, the first friction member and the flange are arranged with a rotation axis, wherein the first friction member and the flange are respectively applied with an axial force such that a frictional force between the holder and the first friction member is greater than a frictional force between the flange and the first friction member when the holder and the flange relatively rotate, wherein the flange includes an arc-shaped through hole and the first friction member includes a protruding portion which is inserted into the arc-shaped through hole of the flange; and at least one damper spring installed in a spring installation part formed by the retainer, the flange and the first friction member, wherein the damper device is configured such that, in an initial state in which the damper spring is uncompressed, a first central angle corresponding to an arc between a first circumferential end of the protrusion and a corresponding first circumferential end of the arc through hole is greater than a second central angle corresponding to an arc between a second circumferential end of the protrusion and a corresponding second circumferential end of the arc through hole, the first central angle is greater than a driving-side maximum rotation angle of the damper device, and the second central angle is less than a sliding-side maximum rotation angle of the damper device.

According to an embodiment of the invention, the holder comprises a first side plate and a second side plate which are connected to each other in a rotationally fixed manner, and the flange is arranged between the first side plate and the second side plate in the axial direction of the vibration damping device, and wherein the first friction member further comprises a friction disc which is arranged between the first side plate and the flange in the axial direction, the friction disc comprising a first surface and a second surface, the first surface of the friction disc being in frictional engagement with the first side plate, the second surface of the friction disc being in frictional engagement with the flange, and the protrusion protruding from the second surface of the friction disc.

According to an embodiment of the invention, the friction disc comprises a window for mounting the damper spring, the length of the window being greater than the length of the damper spring in the initial state in which it is uncompressed.

According to an embodiment of the present invention, the vibration damping device further includes a first elastic member for applying an axial force to the first friction member and a second elastic member for applying an axial force to the flange, the axial force applied to the first friction member by the first elastic member being greater than the axial force applied to the flange by the second elastic member.

According to an embodiment of the present invention, the first elastic member is disposed between the second side plate and the protruding portion in the axial direction, and the second elastic member is disposed between the second side plate and the flange in the axial direction.

According to an embodiment of the invention, the damping device further comprises a second friction member arranged axially between the extension of the first friction member and the second side plate and connected torsionally fast with the second side plate, the first resilient member being arranged to apply an axial force to the second friction member such that the second friction member frictionally engages the first friction member.

According to an embodiment of the invention, the damping device further comprises a third friction element arranged axially between the flange and the second side plate and connected with the second side plate in a torsionally fixed manner, the second resilient element being arranged to apply an axial force to the third friction element such that the third friction element frictionally engages the flange.

According to the embodiment of the invention, the flange comprises a plurality of arc-shaped through holes, the first friction piece comprises a plurality of protruding parts, and the plurality of arc-shaped through holes and the plurality of protruding parts are arranged in a one-to-one correspondence mode.

According to an embodiment of the invention, the first elastic member and the second elastic member are both diaphragm springs.

Another aspect of the invention provides a vehicle including a vibration damping device according to an embodiment of the invention.

In the vibration damping device according to the embodiment of the invention, the protruding portion of the first friction member is arranged to be offset from the arc center position thereof in the arc through hole of the flange such that the protruding portion forms different central angles with respect to both ends of the arc through hole. The first central angle is larger than the maximum rotation angle of the driving side of the vibration damper, so that the vibration damper can be ensured to be subjected to constant damping action in a driving working state. The second central angle is smaller than the maximum rotation angle of the sliding side of the vibration damper, and different damping effects can be generated when the relative rotation angle between the retainer and the flange of the vibration damper is in different ranges in the sliding working state. Specifically, when the relative rotation angle is smaller than the second central angle in the sliding working state, the vibration damping device is subjected to the same damping action as that in the driving working state; when the relative rotation angle is smaller than the second central angle, the vibration damping device is subjected to a larger damping action. Thus, the vibration damping device according to the embodiment of the invention provides different damping actions in the driving operation state and the sliding operation state, and can provide two-stage damping actions in the sliding operation state, thereby improving the damping effect on torsional vibration.

Drawings

FIG. 1 is an exploded view of a vibration damping device according to certain embodiments of the present invention.

FIG. 2 is a side cross-sectional view of a vibration damping device according to certain embodiments of the present invention.

Fig. 3 is a partially enlarged view of a portion a in fig. 2.

Fig. 4 is a front view of a vibration damping device according to some embodiments of the present invention, in which a partial structure is omitted to show the internal configuration thereof, and only a half structure of the vibration damping device is shown.

Fig. 5 is a rear view of a vibration damping device according to some embodiments of the present invention, in which a partial structure is omitted in order to show the internal configuration thereof, and only a half structure of the vibration damping device is shown.

FIG. 6 is a perspective view of a first friction member according to certain embodiments of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention are described with reference to the drawings. The following detailed description and drawings are illustrative of the principles of the invention, which is not limited to the preferred embodiments described, but is defined by the claims. The invention will now be described in detail with reference to exemplary embodiments thereof, some of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which like reference numerals refer to the same or similar elements in different drawings unless otherwise indicated. The aspects described in the following exemplary embodiments do not represent all aspects of the present invention. Rather, these aspects are merely exemplary of the systems and methods according to the various aspects of the present invention as recited in the appended claims.

The invention provides a vibration damping device for a motor vehicle. Hereinafter, exemplary embodiments of the present invention are described with reference to the accompanying drawings. It is to be understood that only certain embodiments of the invention have been shown in the drawings and that the scope of the invention should be determined from the following claims.

FIG. 1 is an exploded view of a vibration damping device according to certain embodiments of the present invention. FIG. 2 is a side cross-sectional view of a vibration damping device according to certain embodiments of the present invention. Fig. 3 is a partially enlarged view of a portion a in fig. 2. Fig. 4 is a front view of a vibration damping device according to some embodiments of the present invention, in which a partial structure is omitted to show the internal configuration thereof, and only a half structure of the vibration damping device is shown. Fig. 5 is a rear view of a vibration damping device according to some embodiments of the present invention, in which a partial structure is omitted in order to show the internal configuration thereof, and only a half structure of the vibration damping device is shown. FIG. 6 is a perspective view of a first friction member according to certain embodiments of the present invention.

According to some embodiments of the present invention, the damping device includes a first side plate 10, a second side plate 20, a flange 30, a damping spring 40, and a first friction member 50.

In the exemplary embodiment, the cage of the vibration damping device includes a first side plate 10 and a second side plate 20. The first side plate 10 and the second side plate 20 are connected together torsionally fixed, for example by means of a connection 120. The flange 20 is rotatable within a predetermined range in the circumferential direction with respect to the holder (the first side plate 10 and the second side plate 20). The flange 20 is disposed between the first side plate 10 and the second side plate 20 in the axial direction of the vibration damping device. The input and output of the vibration damping device are respectively a cage and a flange, wherein the cage is used for being connected to one of a crankshaft of an engine and an input shaft of a gearbox in a torsion-proof manner, and the flange is used for being connected to the other of the crankshaft of the engine and the input shaft of the gearbox in the torsion-proof manner. In other embodiments, the cage may take other configurations.

In the exemplary embodiment, the damping device includes a plurality of damping springs 40. Each of the damper springs 40 is installed in a spring installation portion formed by the first side plate 10, the second side plate 20, the flange 30 and the first friction member 50. In an exemplary embodiment, the first side plate 10 includes spring mounting holes 11, the second side plate 20 includes spring mounting holes 21, the flange 30 includes spring mounting holes 31, and the first friction member 50 includes spring mounting windows 53. The corresponding spring mounting holes 11, 21, 31 and spring mounting window 53 constitute a spring mounting portion. In the exemplary embodiment, the damping device forms a plurality of spring mounts, the number of which is equal to the number of damping springs 40. Preferably, the plurality of spring mounting portions are evenly spaced along a circumferential direction of the vibration damping device. In some embodiments, the length of the spring mounting holes 11, 21, 31 is approximately the same as the initial length of the damper spring 40 when uncompressed. Preferably, the plurality of damper springs 40 are all cylindrical coil springs and have the same size. By mounting the damper springs 40 in the corresponding spring mounting portions, the damper springs 40 are compressed when the first side plate 10/second side plate 20 and the flange 30 rotate relatively, so that the damper springs 40 can function to damp torsional vibration when torque is transmitted between the first side plate 10/second side plate 20 and the flange 30 via the damper springs 40.

In the exemplary embodiment, flange 30 includes an arcuate through bore 32. The connector 120 connects the first side plate 10 and the second side plate 20 together through the arc-shaped through hole 32 in a torsion-proof manner, and is slidable in the arc-shaped through hole 32 in the circumferential direction. Thus, the connector 120 and the arc-shaped through hole 32 define the maximum rotation range of the first/second side plates 10/20 and the flange 30 in the circumferential direction.

In the exemplary embodiment, first friction member 50 includes a friction disk 51 and an extension 52. A friction disc 51 is axially disposed between the first side plate 10 and the flange 20. One axial surface of the friction disk 51 is frictionally engaged with the first side plate 10, and the other axial surface of the friction disk 51 is frictionally engaged with the flange 20. The protrusions 52 protrude from the axial surface of the friction disc 51 that engages the flange 20. In the exemplary embodiment, first friction member 50 includes a plurality of protrusions 52. Preferably, the plurality of protrusions 52 are evenly spaced in the circumferential direction.

The flange 30 also includes an arcuate through bore 33. The protruding portion 52 of the first friction member 50 is adapted to be inserted into the through hole 33 of the flange 30. In the exemplary embodiment, flange 30 includes a plurality of arcuate through-holes 33. Preferably, the plurality of arc-shaped through holes 33 are evenly spaced in the circumferential direction.

According to the embodiment of the present invention, the first friction member 50 and the flange 30 are applied with different axial forces, respectively, so that the frictional force between the first side plate 10 and the first friction member 50 is greater than the frictional force between the flange 30 and the first friction member 50.

As mentioned above, the first friction member 50 also includes a spring mounting window 53. In an exemplary embodiment, the first friction member 50 includes a plurality of spring mounting windows 53. Preferably, the plurality of spring mounting windows 53 are evenly spaced circumferentially. In some embodiments, the damper spring 40 is a linear coil spring. In an exemplary embodiment, the length of the spring mounting window 53 is greater than the initial length of the damper spring 40 when uncompressed. In other embodiments, the damper spring 40 may also be an arcuate coil spring, and the spring mounting portion may also have a corresponding shape.

In the exemplary embodiment, the vibration damping device further includes a second friction member 60, a third friction member 70, a first elastic member 80, and a second elastic member 90. Note that the second friction member 60, the first elastic member 80, and the second elastic member 90 are omitted from fig. 1. Preferably, the first elastic member 80 and the second elastic member 90 are both diaphragm springs. In some embodiments, the first elastic member 80 and/or the second elastic member 90 may be annular. In the exemplary embodiment, first resilient member 80 is axially disposed between second side plate 20 and extension 52 of first friction member 50, and second resilient member 90 is axially disposed between second side plate 20 and flange 30. In some embodiments, the first resilient member 80 and/or the second resilient member 90 is torsionally connected to the second side plate 20.

The first resilient member 80 is adapted to apply an axial force to the first friction member 50 to frictionally engage the first friction member 50 with the first side plate 10, and the second resilient member 90 is adapted to apply an axial force to the flange 20 to frictionally engage the first friction member 50 with the flange 30. In the case where the axial force applied to the first friction member 50 by the first elastic member 80 is in the same direction as the axial force applied to the flange by the second elastic member 90, as shown in fig. 2 and 3, the axial force applied to the first friction member 50 by the first elastic member 80 may be selectively set to be greater than the axial force applied to the flange 30 by the second elastic member 90, so that the frictional force between the first side plate 10 and the first friction member 50 is greater than the frictional force between the flange 30 and the first friction member 50. Alternatively, the axial force applied by the first elastic element 80 to the first friction element 50 may also be set to be less than or equal to the axial force applied by the second elastic element 90 to the flange 30, which also enables the axial force between the first side plate 10 and the first friction element 50 to be greater than the axial force between the flange 30 and the first friction element 50, and also enables the friction force between the first side plate 10 and the first friction element 50 to be greater than the friction force between the flange 30 and the first friction element 50 when the friction coefficients of the two friction pairs are the same or different.

In the exemplary embodiment, the second friction member 60 is disposed axially between the extension 52 of the first friction member 50 and the second side plate 20. The second friction element 60 is connected to the second side plate 20 in a rotationally fixed manner. The first resilient member 80 abuts the second friction member 60 and applies an axial force to the second friction member 60 in the axial direction, so that the second friction member 60 applies an axial force to the first friction member 50 in the axial direction.

In the exemplary embodiment, a third friction member 70 is disposed axially between flange 30 and second side plate 20. The third friction element 70 is connected to the second side plate 20 in a rotationally fixed manner. The second resilient member 90 abuts the third friction member 70 and applies an axial force to the third friction member 70 in the axial direction, so that the third friction member 70 applies an axial force to the flange 20 in the axial direction.

In an exemplary embodiment, the first friction member 50, the second friction member 60, and the third friction member 70 are all annular friction members. However, the present invention is not limited thereto. Other non-annular configurations for the friction members are also contemplated.

According to the embodiment of the present invention, as shown in fig. 4, in the initial state where the damper spring 40 is uncompressed, the protruding portion 52 of the first friction member 50 is offset from the arc center position of the arc through hole 33 in the arc through hole 33 of the flange 30. Specifically, as shown in fig. 4, the arc between the first circumferential end of the protruding portion 52 and the corresponding first circumferential end of the arc-shaped through hole 33 forms a first central angle D, and the arc between the second circumferential end of the protruding portion 52 and the corresponding second circumferential end of the arc-shaped through hole 33 forms a second central angle C. The first central angle D is greater than the second central angle C. The first central angle D is greater than the driving-side maximum rotation angle of the vibration damping device, and the second central angle C is less than the coasting-side maximum rotation angle of the vibration damping device. The driving-side maximum rotational angle of the vibration damping device means the maximum rotational angle between the first side plate 10/second side plate 20 (cage) and the flange 30 of the vibration damping device when the engine to which the vibration damping device is connected is in a driving operation state. The sliding-side maximum rotational angle of the damper device indicates the maximum rotational angle between the first side plate 10/second side plate 20 (cage) and the flange 30 of the damper device when the engine to which the damper device is connected is in the sliding operating state.

In an exemplary embodiment, as described above, the length of the spring mounting window 53 is greater than the initial length of the damper spring 40 when uncompressed, whereby relative rotation of the first friction member 50 and the damper spring 40 may occur. In the exemplary embodiment, as shown in fig. 5, when one end of the damper spring 40 is engaged with one end of the spring mounting window 53, an angle between a line connecting the other end of the damper spring 40 to the shaft center of the damper device and a line connecting the other end of the spring mounting window 53 to the shaft center is equal to the second central angle C.

In an exemplary embodiment, based on the structure described above, the vibration damping device may form four friction pairs as follows.

The coefficients of friction for the four friction pairs FP 1-FP 4 in the above table may be set to be the same or, alternatively, may be different depending on the actual hysteresis requirements. This is generally determined by the materials of the various components selected and the physical properties of the friction surfaces, and may be chosen arbitrarily according to the actual requirements.

Hereinafter, the operation principle of the vibration damping device according to the embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, a flange 30 is used for a rotationally fixed connection to the crankshaft of the engine and the first side plate 10/second side plate 20 (cage) is used for a rotationally fixed connection to the input shaft of the gearbox. However, it should be understood that the present invention is not limited thereto.

In the driving operation of the vibration damping device, it is assumed, for example, that the flange 30 is driven to rotate in the counterclockwise direction (fig. 4) with respect to the first side plate 10/the second side plate 20. Since the friction force between the first friction piece 50 and the first side plate 10/the second side plate 20 (the retainer) (the sum of the friction force received by the first friction piece 50 at the first friction pair FP1 and the friction force received at the second friction pair FP 2) is greater than the friction force between the first friction piece 50 and the flange 30 (the sum of the friction force received by the first friction piece 50 at the third friction pair FP3 and the friction force received at the fourth friction pair FP 4), the first friction piece 50 and the first side plate 10/the second side plate 20 do not rotate relative to each other, and rotate relative to the flange 30. At this point, the protrusion 52 moves in a clockwise direction (FIG. 4) in the arcuate through hole 33 and the friction pairs FP3 and FP4 damp this relative rotation. Since the first central angle D is designed to be larger than the driving-side maximum rotational angle of the vibration damping device, the first circumferential end portion of the protruding portion 52 does not come into contact with the corresponding first circumferential end portion of the arc through hole 33 in the driving operation state of the vibration damping device, and therefore, it is possible to ensure that the vibration damping device is subjected to a constant damping action in the driving operation state.

In the sliding operation state of the vibration damping device, it is assumed, for example, that the first side plate 10/the second side plate 20 is driven to rotate in the counterclockwise direction (fig. 4) with respect to the flange 30. The damping device will be subjected to two different damping actions depending on the relative rotational angle of the flange 30 and the first side plate 10/the second side plate 20. When the relative rotation angle is smaller than the second central angle C, since the frictional force between the first friction member 50 and the first side plate 10/the second side plate 20 (the cage) (the sum of the frictional force received by the first friction member 50 at the first friction pair FP1 and the frictional force received at the second friction pair FP 2) is larger than the frictional force between the first friction member 50 and the flange 30 (the sum of the frictional force received by the first friction member 50 at the third friction pair FP3 and the frictional force received at the fourth friction pair FP 4), the first friction member 50 rotates together with the first side plate 10/the second side plate 20 and generates relative rotation with the flange 30. At this point, the protrusion 52 moves in the arc-shaped through hole 33 in the counterclockwise direction (fig. 4), and the friction pairs FP3 and FP4 damp the relative rotation. Since the relative rotational angle is smaller than the second central angle C, the second circumferential end portion of the projecting portion 52 does not contact the corresponding second circumferential end portion of the arc through hole 33, and therefore the damping action received by the vibration damping device in this state is the same as in the driving operation state.

When the relative rotation angle between the flange 30 and the first side plate 10/the second side plate 20 is greater than the second central angle C, the second circumferential end of the protruding portion 52 of the first friction member 50 will contact with the corresponding second circumferential end of the arc-shaped through hole 33 of the flange 30, so that the first friction member 50 and the flange 30 will not rotate relatively, but rotate relatively with the first side plate 10/the second side plate 20. At this point, the friction pairs FP1, FP2 and FP4 produce a damping effect on this relative rotation.

When the vibration damping device is in the sliding operating state and the relative rotation angle is greater than the second central angle C, the first friction member 50 can be driven by the vibration damping spring 40 to rotate relative to the flange 30. For example, assume that the first side plate 10/second side plate 20 are driven to rotate in a counterclockwise direction (fig. 4) relative to the flange 30. When the relative rotation angle is smaller than the second central angle C, the first friction member 50 rotates together with the first side plate 10/the second side plate 20 and generates relative rotation with the flange 30 as described above. At this time, the damper spring 40 does not exert a force on the first friction member 50 in the spring mounting window 53, and the friction pair FP3 and FP4 exert a damping effect on the relative rotation. When the relative rotation angle is larger than the second central angle C, one end of the damper spring 40 will contact the spring mounting window 53, so that the first friction member 50 and the flange 30 will not rotate relative to each other under the driving of the damper spring 40, and will rotate relative to the first side plate 10/the second side plate 20. At this point, the friction pairs FP1, FP2 and FP4 produce a damping effect on this relative rotation.

Therefore, when the relative rotation angle of the flange 30 and the first side plate 10/the second side plate 20 is smaller than the second central angle C in the sliding operation state of the vibration damping device, the friction pair FP3 and FP4 generate a damping effect on the relative rotation; when the second central angle C is larger, the friction pairs FP1, FP2 and FP4 generate damping effect on relative rotation. Since the sum of the frictional forces experienced by the first friction member 50 at the friction pairs FP3 and FP4 is smaller than the sum of the frictional forces experienced by the first friction member 50 at the friction pairs FP1, FP2 and FP4, the vibration damping device will experience a greater damping effect when the relative rotation angle is greater than the second central angle C in the sliding operation state. In this way, the vibration damping device according to the embodiment of the invention can produce a two-stage damping action in the sliding operation state.

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the construction and methods of the embodiments described above. On the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements and method steps of the disclosed invention are shown in various example combinations and configurations, other combinations, including more, less or all, of the elements or methods are also within the scope of the invention.