JPH04249631A - Rotary damper - Google Patents

Abstract

PURPOSE:To change the damping force characteristic in all the operation speed region according to the operation direction. CONSTITUTION:A vane 4 is installed on a swing shaft 1 which is concentrically arranged on the inside of a cylindrical casing 2, and the oil chambers which are dividedly formed on both the sides of the vane in the casing are allowed to communicate through the sliding gap between the vane and the casing and the orifices 11A and 11B formed in series on the vane and check valves 10A and 10B.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a rotary damper for damping rocking motion.

0002

[Prior art] For example, a rotary damper is
As shown in No. 2152, a vane whose base end is fixed to a swing shaft is housed inside a cylindrical casing so that the vane can swing freely with the tip slidingly touching the inner circumference of the casing. A plurality of oil chambers defined inside the oil chamber are communicated with each other via a damping valve.

When the vane swings together with the swing shaft, the oil chamber defined in the vane expands and contracts, and the hydraulic oil in the contracting oil chamber is transferred to the expanding oil chamber through the sliding gap between the vane and the casing.
Alternatively, the fluid flows through a damping valve, and the flow resistance at that time generates a damping force to damp the vibration.

0004

However, with this structure, the damping force characteristics cannot be changed depending on the swinging direction of the damper. In such cases, the damping force generated on the rebound side and the compression side would be the same, making it impossible to obtain desirable damping performance.

[0005] Regarding this, in the previously filed Japanese Patent Application No. 2-43356, the present applicant installed relief valves with different relief pressures in passages communicating between expanding and contracting oil chambers, and changed the direction of flow of hydraulic oil. We are proposing a rotary damper in which each relief valve operates according to the situation.

However, in this case as well, in low-speed operating conditions where the pressure in the contracting oil chamber is less than the set relief pressure, the hydraulic oil flows exclusively through the sliding gap between the vane and the casing, so that the expansion side and The compression side damping force characteristics were still the same.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a rotary damper in which damping force characteristics vary over the entire operating speed range depending on the operating direction.

[0008]

[Means for Accomplishing the Problems] The present invention has a vane attached to a swing shaft concentrically arranged inside a cylindrical casing, and an oil chamber defined on both sides of the vane inside the casing. It communicates with the sliding gap between the vane and the casing, as well as with an orifice provided in series with the vane and a check valve.

[0009]

[Operation] During operation in one direction, hydraulic oil flows through the orifice and the sliding gap, and in the opposite direction, hydraulic oil flows only through the sliding gap. Therefore, different damping forces are generated depending on the direction of operation, and the difference in damping force extends over the entire range of operating speeds.

0010

Embodiments FIGS. 1 to 7 show embodiments of the present invention.

In FIG. 1, reference numeral 1 denotes a hollow swing shaft supported concentrically inside a casing 2;
The vane 4 shown above in FIG. 3 is integrally constructed.

The vanes 4 extend radially at intervals of 180° from the swing axis 1 and are integrally fixed to a plate-shaped vane main body 5 whose tips are close to the inner periphery of the casing 2 and to both ends of the vane main body 5. It consists of a pair of disc-shaped side plates 6A and 6B whose outer periphery is in sliding contact with the inner periphery of the casing 2.

A pair of stoppers 7 as shown in FIG. 5 are provided on the inner periphery of the casing 2 to restrict the swinging of the vane 4 within a certain range.
A and 7B are stuck together, and this causes 4 to be attached to the inside of casing 2.
Three oil chambers 8A, 8B, 9A, and 9B are defined.

[0014] An oil chamber 8A is provided in one vane main body 5.
A plate-shaped check valve 1 as shown in FIG.
0A and orifice 11A are arranged in series. The check valve 10A only allows hydraulic oil to flow from the oil chamber 8A to the oil chamber 9A.

Similarly, the other vane body 5 has a check valve 10B and an orifice 1 that communicate the oil chambers 8B and 9B.
1B is provided.

The side plate 6B has oil chambers 8A, 8B,
Port 1 as shown in Figure 2 facing 9A and 9B respectively
2A, 12B, 13A, and 13B are provided. port 1
The ports 2A and 12B and the ports 13A and 13B communicate with each other via annular grooves formed in the side plate 6B, respectively.

Furthermore, a bearing 1 is provided on the inner circumference of the casing 2.
A disk-shaped member 16 that supports the swing shaft 1 in sliding contact with the side plate 6A is fixed to the outer periphery of the end of the swing shaft 1 in contact with the side plate 6B. A hollow portion 1A of the swing shaft 1 opens inside the casing 2 toward a cap 17 that seals the end of the casing 2.

The member 16 is provided with a check valve 14 communicating with ports 12A and 12B, and a check valve 15 communicating with ports 13A and 13B. These check valves 1
4 and 15 are connected to the hollow part 1A of the swing shaft 1 through holes formed in the member 16, the check valve 14 is connected from the hollow part 1A to the port 12A (12B), and the check valve 15 is connected from the hollow part 1A to the port. Only oil passage in the 13A (13B) direction is allowed.

On the other hand, an enlarged diameter portion 1B continuous to the side plate 6A is formed at the end of the swing shaft 1 on the side plate 6A side. The enlarged diameter portion 1B projects outward from the end of the casing 2 while allowing the bearing 18 attached to the outer periphery to freely rotate and slide on the inner periphery of the casing 2.

An accumulator 19 communicating with the hollow portion 1A is housed inside the enlarged diameter portion 1B.

Next, the operation will be explained.

As shown in FIG. 7, for example, this rotary damper is installed at the base end of a swing arm 21 that supports a rear wheel 20 of a two-wheeled vehicle on a vehicle body 22.

In this case, the rotary damper is installed so that the oil chambers 8A and 8B in FIG. 5 contract in response to the pressure side operation of the swing arm 21, that is, the vane 4 is swung counterclockwise.

[0024] As a result, the hydraulic oil in the oil chambers 8A and 8B, which shrinks in response to pressure side operation, is transferred to the vane main body 5 and the casing 2.
The oil flows into the expanding oil chambers 9A and 9B from the gap between them.

At the same time, the hydraulic oil in the oil chamber 8A flows through the orifice 11.
The hydraulic oil in the oil chamber 8B flows into the oil chamber 9B through the orifice 11B and the check valve 10B.

As a result, as shown in FIG. 6, the compression side damping force characteristic has a characteristic a due to the hydraulic oil flowing through the gap between the vane body 5 and the casing 2, and a characteristic b due to the hydraulic oil flowing through the orifices 11A and 11B. This becomes the synthesized characteristic c.

On the other hand, for the expansion side operation, the vane 4 swings in the opposite direction and contracts the oil chambers 9A and 9B, but since the check valves 10A and 10B are closed, the hydraulic oil flows into the vane body 5. It flows only through the gap between the casing 2 and the casing 2, and the
generates the same damping force as characteristic a.

Therefore, irrespective of the operating speed range, a larger damping force is always generated during the expansion side operation than during the compression side operation, and favorable damping characteristics can be obtained.

Incidentally, fluctuations in the hydraulic oil volume due to changes in oil temperature are absorbed by the hydraulic oil supplied from the accumulator 19 via the check valves 14 and 15.

[0030]

As described above, in the present invention, the oil chambers on both sides of the vane communicate with each other through the sliding gap of the vane, and the orifice and check valve are provided in series with the vane.
The generated damping force differs depending on the direction in which the vane swings, and the generated damping force also differs over the entire swing speed range. Therefore, if the present invention is applied to a shock absorbing mechanism for a two-wheeled vehicle or the like, the damping force on the rebound side and the compression side can be set arbitrarily, and preferred shock absorbing characteristics can be easily achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a rotary damper showing an embodiment of the present invention.

FIG. 2 is a view taken along the line A-A in FIG. 1;

FIG. 3 is a perspective view of a vane and a swing shaft.

FIG. 4 is a longitudinal sectional view of an orifice and a check valve.

FIG. 5 is a composite diagram of a schematic cross-sectional view of the rotary damper and a hydraulic circuit diagram.

FIG. 6 is a graph showing damping force characteristics of a rotary damper.

FIG. 7 is a schematic side view of the swing arm of the two-wheeled vehicle.

[Explanation of symbols]

1 Swing axis 2 Casing 4 Vane 5 Vane body part 6A, 6B Side plate 8A, 8B, 9A, 9B Oil chamber 10A, 10B Check valve 11A, 11B Orifice

Claims (1)

[Claims] Claim 1: A vane is attached to a swing shaft arranged concentrically inside a cylindrical casing, and a sliding gap between the vane and the casing is installed between the oil chambers defined on both sides of the vane inside the casing. , and a rotary damper characterized by communicating with an orifice provided in series with the vane and a check valve.