JP2000002282A - Rotary damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary damper which can generate stable attenuation force by adopting highly viscous fluid as an operation oil, even it is a small- sized vane type rotary damper, permits high pressure operation and improve freedom of tuning of generated attenuation characteristics. SOLUTION: In a rotary damper, fluid chambers a1 and a2 are communicated with each other through a throttle passage, which chambers are partitioned by partition walls 23a, 23b and vanes 4a, 4b. In such a rotary damper, the throttle passage communicating the chambers a1 and a2 with each other is made up of clearances 3a, 3b formed between a tubular housing 2 and the vanes 4a, 4b. Variable throttle means 5a, 5b are arranged for throttling the throttle passage made up of the clearances 3a, 3b according to pressure difference P generated between the fluid chambers al and a2 due to the relative rotation of a circular housing 2 and a rotary shaft 1, the chambers being partitioned by the partition walls 23a, 23b and the vanes 4a, 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane type rotary damper which is provided, for example, on a rotation bearing of a lower arm or an upper arm of a vehicle to attenuate the rotation of the arm.

[0002]

2. Description of the Related Art Conventionally, as a vane type rotary damper, for example, a "rotary shock absorber" described in JP-A-5-33822 is known. This conventional rotary shock absorber (rotary damper)
Is a cylindrical housing filled with viscous oil (hydraulic oil), a rotating shaft inserted into the housing along its axis and rotatably supported, and a space between the rotating shaft and the inner wall of the housing. A rotor (vane) that partitions the inside of the housing into a plurality of chambers by the partition wall fixed to the rotation shaft and the partition wall, and a throttle passage communicating between the rotor or the chamber partitioned by the housing. And a check valve.

[0003]

However, the conventional vane type rotary damper is set to have a larger lever ratio than the reciprocating type damper, so that the same damping force is generated at the wheel tip. Requires a high damping force according to the increase in the lever ratio.
In other words, the need for a compact and high damping force means that the pressure inside the damper chamber increases and the movement flow rate of the hydraulic oil in the damper decreases, so that a high airtightness is required to generate a stable high damping force. Nature is required.
However, in the vane type rotary damper,
Due to the longer length of the movable seal between the housing and the vane, if low-viscosity oil is used as the working fluid,
The amount of leakage from the movable seal portion is large, and it is difficult to obtain a high damping force. Therefore, in general, it is conceivable to increase the viscosity of the hydraulic oil in order to suppress the leakage of the hydraulic oil from the movable seal portion. However, simply increasing the viscosity of the hydraulic oil causes the following problems. Occurs. In other words, when high-viscosity hydraulic oil flows through the throttle pipe,
The speed distribution is as shown in FIG. 10, and in a portion where there is a speed difference, a resistance force is generated when the hydraulic oil is relatively sheared, so that a differential pressure ΔP (damping force) is generated. However, in actuality, as shown in the kinematic viscosity characteristics versus the shear rate in FIG. 11, the apparent viscosity decreases as the shear rate increases, resulting in a velocity distribution as shown in FIG. Further, in a current damper using a hydraulic oil such as a mineral oil having a low viscosity, the Reynolds number (Re number) is large. As shown in FIG. 14B, since the pressure difference takes a substantially constant value, the differential pressure ΔP becomes ΔP∝Q ² when the flow path cross-sectional area (A) is constant, and the flow rate Q (relative rotation speed) in FIG. (Damping force) as shown in the characteristic diagram (dotted line), a damping force having a square characteristic with respect to the relative rotation speed is obtained, whereby the damping force rapidly increases in a high rotation speed region. It was possible to raise.

The Reynolds number (Re number) is expressed by the following equation. Re = (v · d) / ν where v is the average flow velocity, d is the diameter of the throttle tube, and ν is the kinematic viscosity. The average flow velocity v is expressed by the following equation. v = (Q ² · 4) / (π · d ² ) However, when a highly viscous hydraulic oil is used, the Reynolds number (Re number) becomes small. Therefore, the flow coefficient (Re number) with respect to the Reynolds number (Re number) in FIG. Cd) As shown in the area A in the value characteristic diagram, the average flow velocity v, that is, the flow rate (v = Q
/ A), the flow coefficient (Cd) value sharply changes greatly, and the differential pressure ΔP becomes ΔP∝Q ² / Cd ² when the flow path cross-sectional area (A) is constant. As shown in the characteristic diagram (solid line) of the differential pressure ΔP (damping force) with respect to the flow rate Q (relative rotation speed) in FIG. 14, the characteristics become almost linear, and the square rotation characteristic damping force is obtained with respect to the relative rotation speed. Disappears. Therefore, there is a problem that the damping force cannot be significantly increased in the high relative rotation speed range. That is, when using a low-viscosity oil in which the differential pressure ΔP characteristic with respect to the flow rate Q has a downward convex square characteristic, 3 /
It was possible to tune the degree of the curve of the damping force characteristic relatively freely by combining it with the valve characteristic that generates a squared characteristic. However, when a high-viscosity oil is used, as shown by the solid line in FIG. Differential pressure ΔP against flow rate Q
Is substantially linear, and as described above, the effect of the change in the kinematic viscosity characteristic on the shear rate in the high-viscosity oil (ie, as shown in FIG. 11, the apparent viscosity decreases as the shear rate increases). 15), it is extremely difficult to significantly increase the damping force in the high rotation speed range, as shown by the solid line in FIG.
Therefore, when a large input suddenly enters from the road surface as in the past, tuning is performed so that the generated damping force in the high operating speed region is sharply increased to generate characteristics that reduce excessive input to the vehicle body. Is difficult. As described in detail above, the use of high-viscosity oil drastically reduces the leakage of hydraulic oil from gaps, thereby enabling stable damping force to be generated even in a small damper with a small flow rate. Although the pressure can be increased and the pressure can be increased, there is a problem that the degree of freedom in tuning the generated damping force characteristic is reduced.

The present invention has been made in view of the above-mentioned conventional problems. By using a high-viscosity fluid as a hydraulic oil, stable damping can be achieved even in a small vane type rotary damper having a small flow rate. It is an object of the present invention to provide a rotary damper that can generate a force, can increase the pressure, and can increase the degree of freedom in tuning the generated damping force characteristic.

[0006]

According to a first aspect of the present invention, there is provided a rotary damper comprising a housing and a rotary shaft rotatably supported by a shaft of the housing. A pressure chamber filled with a viscous fluid is formed therebetween, and the pressure chamber is defined as at least two fluid chambers by a partition formed on the housing side and a vane provided on a rotating shaft side. In a rotary damper in which at least two fluid chambers defined by a vane are connected by a throttle channel, a throttle channel communicating between the two fluid chambers is formed between the housing and the vane. And / or at least two fluid chambers defined by the partition and the vane by relative rotation between the housing and the rotary shaft. Variable throttle means for narrowing a throttle channel formed by a gap formed between the housing and the vane and / or a gap formed between the rotating shaft and the partition according to a differential pressure generated therebetween. Means. According to a second aspect of the present invention, in the rotary damper according to the first aspect, the variable throttling means is provided in the vane and / or the partition wall, and the pressurized fluid chamber according to a differential pressure generated between the two fluid chambers. Receiving the fluid pressure, the valve operates in a direction in which a throttle channel formed by a gap formed between the housing and the vane and / or a gap formed between the rotation shaft and the partition wall is throttled. Vane,
And a biasing member for biasing the variable vanes in a direction to widen the throttle flow path. According to a third aspect of the present invention, in the rotary damper according to the second aspect, the urging member is formed of a leaf spring. According to a fourth aspect of the present invention, in the rotary damper according to the second or third aspect, the variable throttle means are separately provided in correspondence with a relative rotation direction between the housing and a rotation shaft. The urging means have different urging forces. According to a fifth aspect of the present invention, in the rotary damper according to the second to fourth aspects, the variable vanes in the variable throttle means are configured to receive the fluid pressure of the pressurized fluid chamber through the throttle.

[0007]

In the rotary damper according to the first aspect of the present invention,
Due to the above-described configuration, when the housing and the rotation shaft are relatively rotated, the flow of the fluid between at least two fluid chambers defined by the partition wall and the vane is reduced when the fluid flows through the throttle passage. As a result, a predetermined damping force is generated.
When a high-viscosity fluid is used as the viscous fluid, if the cross-sectional area of the throttle channel is constant, the differential pressure (damping force) characteristics with respect to the flow rate (relative rotation speed) become linear characteristics. In addition, due to the influence of the change in the kinematic viscosity characteristic on the shear rate in the high-viscosity fluid, the damping force cannot be significantly increased in the high-speed relative rotation range. However, in the vehicle damper according to the present invention, the relative pressure between the at least two fluid chambers defined by the partition and the vane due to the relative rotation of the housing and the rotation shaft may cause the pressure difference to be increased. The high-speed relative rotation is achieved by operating the variable throttle means in the direction of narrowing the throttle channel formed by the gap formed between the housing and the vane and / or the gap formed between the rotating shaft and the partition. It is possible to freely increase the degree of rise of the damping force in the moving range. Therefore,
For example, when used as a rotary damper for a vehicle, an excessive input to the vehicle body can be reduced by rapidly increasing a damping force in response to a sudden excessive input from a road surface. Further, by changing the throttle characteristic with respect to the differential pressure in the variable throttle means, it is possible to freely tune the generated damping force characteristic with respect to the damper operating speed.
Therefore, by using a high-viscosity fluid as the viscous fluid, it is possible to generate a stable damping force even in a small damper having a small flow rate, and it is possible to increase the pressure and to tune the characteristic of the generated damping force. The degree of freedom is increased. According to a second aspect of the present invention, in the rotary damper according to the first aspect, the variable throttling means is provided in the vane and / or the partition wall, and the pressurized fluid chamber according to a differential pressure generated between the two fluid chambers. Receiving the fluid pressure, the throttle passage formed by the gap formed between the housing and the vane and / or the gap formed between the rotary shaft and the partition wall is provided with an urging member. The variable vane operates in the direction of narrowing down against the force, thereby reducing the total cross-sectional area of the narrowing flow path according to the relative rotation speed without using an electric actuator or the like. Can be changed. Further, the variable vane constituting the variable throttle means is urged by the urging member in a direction in which the throttling flow path is widened, whereby the initial positioning of the variable vane is performed and the urging force setting of the urging member is performed. Thereby, the operating point of the variable vane can be set freely. According to the third aspect of the present invention, in the rotary damper according to the second aspect, since the biasing member is formed of a leaf spring, the rotary damper can be housed compactly even in a limited space such as a partition wall or a vane. . According to a fourth aspect of the present invention, in the rotary damper according to the second or third aspect, the variable throttle means are separately provided in correspondence with a relative rotation direction between the housing and a rotation shaft. Since the urging forces of the urging means are different from each other, the amount of restriction of the restricting flow path by the variable vane is different depending on the relative rotation direction, whereby different damping force characteristics are obtained depending on the relative rotation direction. According to a fifth aspect of the present invention, in the rotary damper according to the second to fourth aspects, the variable vane in the variable throttle means receives the fluid pressure of the pressurized-side fluid chamber through the throttle. When the relative rotation frequency between the housing and the vane is small, the differential pressure is transmitted to the variable vane via the throttle, thereby operating the variable vane. And / or a throttle channel formed by a gap formed between the rotary shaft and the partition wall, is operated in a direction to narrow the throttle channel against the urging force of the urging means, and the relative rotation speed is increased. However, when the relative rotation frequency is high, the relative rotation direction is switched before the differential pressure is transmitted to the variable vanes, so that the variable vanes are activated. Instead of Flow path is maintained in a state which is not narrowed. Therefore, the damping force characteristic can be changed in response to the relative rotation frequency.

[0008]

Embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention.
2 is a cross-sectional view (cross-sectional view taken along line S1-S1 in FIG. 2) of the rotary damper, FIG. 2 is a cross-sectional view taken along line S2-S2 in FIG. 1, FIG. , FIG.
3 is a sectional view taken along lines S4-S4 and S5-S5 in FIG. 3, and FIG. 5 is a sectional view and a perspective view showing a state of attachment to a vehicle. The rotary damper of the first aspect includes a rotary shaft 1 connected and fixed to the vehicle body B side, and an annular housing 2 connected and fixed to the upper arm A on the vehicle body bearing side. In FIG. 5, reference numeral 41 denotes a pan rubber, 42 denotes a torque transmission arm, 43 denotes a rebound stopper, 44 denotes a lower arm,
5 indicates a spring, and 46 indicates a wheel.

First, as shown in FIGS. 1 and 2, the annular housing 2 is formed by disc-shaped left and right side walls 21 and 22 having axial holes 21a and 22a and outer peripheral sides of the side walls 21 and 22. And an outer peripheral cylindrical portion 23 to be connected. By mounting the shaft holes 21a and 22a of the left and right side walls 21 and 22 to the rotating shaft 1 via bearings 24 and 25, respectively, the annular housing 2 can be relatively rotated with respect to the rotating shaft 1. It is attached to the state.

The outer cylindrical portion 23 is formed to have a different inner diameter with a ridge 23c formed at the center of the inner surface. The outer cylindrical portion 23 is press-fitted and fixed to the inner surface of the ridge 23c. It is provided in the state where it was set. The projection 23c is assembled in a state of being sandwiched between the left and right side walls 21 and 22, and the left opening edge of the outer peripheral cylindrical portion 23 is welded to the outer peripheral surface of the left side wall 21 at the time of assembly. The right opening edge of the outer peripheral cylindrical portion 23 is fixed integrally by caulking to the outer peripheral surface side of the right side wall 22 at the time of assembling.
6, the space between the right side wall 22 and the right side wall 22 is hydraulically sealed.

The outer peripheral cylindrical portion 23 is formed in a substantially cylindrical shape as shown in a sectional view of FIG. 2, and a pair of upper and lower substantially fan-shaped rotary cylinder chambers (fluids) are formed by left and right partitions 23a and 23b. Chambers are formed, and each of the two rotary cylinder chambers is circumferentially provided with two fluid chambers a1 and 4b by a pair of left and right vanes 4a and 4b in which an annular shaft portion 4c is fitted and fixed to the outer periphery of the rotary shaft 1. The fluid chambers a1 and a2 are filled with a highly viscous fluid such as silicone oil as a working oil. And the annular shaft center 4c.
The outer peripheral surfaces of the upper and lower partitions slidably abut against the inner circular arc surfaces of the distal ends of the left and right partition walls 23a and 23b, respectively, so that a pair of upper and lower substantially fan-shaped rotary cylinder chambers are sealed hydraulically.

Between the inner peripheral surface of the outer cylindrical portion 23 of the annular housing 2 and the front end surface of each of the vanes 4a, 4b, there are formed gaps 3a, 3b constituting a predetermined throttle flow path. Three fluid chambers a1 via 3a and 3b
−a2 are in communication with each other.

In the first embodiment of the present invention, two fluid chambers a1 defined by the partition walls 23a and 23b and the vanes 4a and 4b by the relative rotation of the annular housing 2 and the rotation shaft 1. -A2 are formed by gaps 3a, 3b formed between the inner peripheral surface of the outer peripheral cylindrical portion 23 of the annular housing 2 and the distal end surfaces of the vanes 4a, 4b in accordance with the differential pressure ΔP generated between them. Variable throttle means 5a and 5b for narrowing the throttle flow path are respectively incorporated in the vanes 4a and 4b.

The variable throttle means 5a and 5b receive the fluid pressure in the pressurized fluid chamber in accordance with the pressure difference ΔP generated between the two fluid chambers a1 and a2, thereby forming the gap forming the throttle channel. The variable vane 50 is configured to operate in a direction of narrowing the variable vanes 3a and 3b, and an urging member 51 for urging the variable vane 50 in a direction of expanding the gaps 3a and 3b. That is, as shown in detail in FIGS. 3 to 5, each vane 4a, 4b forming a gap 3a, 3b between the inner peripheral surface of the outer cylindrical portion 23 and the vane 4a ,
Two grooves 6 penetrating in the width direction of the shaft 4b (axial direction of the rotating shaft 1) are formed side by side in the thickness direction of the vanes 4a and 4b, and the variable vanes 50 slide in the respective grooves 6 in the radial direction. It is housed freely. Each groove 6 has a step 6a at its bottom side.
Is formed to form a wide enlarged portion 6b in the thickness direction of each of the vanes 4a and 4b, while an enlarged pressure receiving portion 50a is formed at the base end of the variable vane 50 so as to slide on the inner surface of the enlarged portion 6b. In the enlarged portion 6b between the enlarged pressure receiving portion 50a and the stepped portion 6a, an urging member 51 constituted by a plurality of portal leaf springs is accommodated. And both each step 6a
A support member 7 having a fulcrum 7a projecting from the middle portion of the biasing member 51 is accommodated between the first and second biasing members 51, while the middle portion of the enlarged pressure receiving portion 50a is accommodated in the middle portion of the enlarged pressure receiving portion 50a. An escape groove 50b for accommodating the amount of bending of the urging member 51 is formed. The variable aperture means 5
The urging members 51 and 51 in a and 5b have different urging forces.

An enlarged portion 6 facing the enlarged pressure receiving portion 50a.
The bottom of b is connected to a fluid chamber a farther from each other by communicating pressure holes (restrictors) 4d and 4e formed in the vanes 4a and 4b.
1 and a2, and between the fluid chambers a1 and a2, which are closer to the support member 7 side end of the enlarged portion 6b, respectively, are communicated with the discharge communication holes 4f and 4g.

Next, the operation of the first embodiment of the invention will be described. (A) Damping Force Generation Action Since the rotary damper according to the first embodiment of the present invention is configured as described above, when the rotation shaft 1 and the annular housing 2 relatively rotate, for example, the rotation in FIG. When the shaft 1 rotates counterclockwise, the fluid chamber a of the two fluid chambers a1 and a2 defined by the vanes 4a and 4b, respectively,
Since the first side is pressurized and the fluid chamber a2 side is depressurized, the high-viscosity fluid on the fluid chamber a1 side flows through the gaps 3a and 3b to the other fluid chamber a2. A predetermined damping force is generated by the flow resistance when passing through the throttle channel formed by the gaps 3a and 3b.

Contrary to the above, when the rotating shaft 1 rotates clockwise in FIG. 2, the fluid chamber of the two fluid chambers a1 and a2 defined by the vanes 4a and 4b, respectively. a2 side is pressurized and the fluid chamber a1 side is depressurized,
When the high-viscosity fluid on the fluid chamber a2 side flows through the gaps 3a and 3b to the other fluid chamber a1, and when the high-viscosity fluid passes through the throttle channel formed by the gaps 3a and 3b, A predetermined damping force is generated by the flow resistance.

(B) Variation of damping force characteristics with respect to relative rotational speed a) Low rotational speed region When the annular housing 2 and the rotational shaft 1 rotate relative to each other, a predetermined difference between the two fluid chambers a1 and a2 is obtained. Pressure ΔP is generated,
The enlarged pressure receiving portion 50a of each variable vane 50 receives the hydraulic pressure on the pressurizing chamber side via the pressure receiving communication hole 4d or 4e, so that the variable vanes 50 are narrowed in the direction of narrowing the gaps 3a and 3b.
A force to press and slide is applied.

However, when the relative rotation speed between the annular housing 2 and the rotation shaft 1 is low, the two fluid chambers a1, a2
Is small, the variable vane 50 does not operate due to the urging force of the urging member 51, so that the gap 3a,
3b is kept open.

B) High rotation speed range As the relative rotation speed between the annular housing 2 and the rotation shaft 1 increases, the pressure difference ΔP between the two fluid chambers a1 and a2 increases. The gaps 3a, 3a against the urging force
The variable vane 50 is pressed and slid in the direction of narrowing the gap b, thereby acting in the direction of narrowing the gaps 3a and 3b.

Here, in general, the differential pressure ΔP between the two fluid chambers a1 and a2 when flowing through the gaps 3a and 3b (throttle channels).
[Kgf / cm ² ] is represented by the following equation (1). ΔP = {(12 · μ · L) / (b · h ³ )} · {Q − ((b · h) / 2) · U)} (1) where μ is the fluid viscosity [ kg · s / cm ² ], h is the height of the gap between the housing and the vane [cm], Q is the flow rate, and U is the moving speed of the vane (the relative rotation speed between the housing and the vane).
[Cm / s], b is the width of the vane [cm], L is the length of the gap [c
m].

As is apparent from the above equation (1), the gap 3
When the height h is reduced by narrowing down the apertures a and 3b, the differential pressure ΔP increases. As shown in FIG. 7, the damping force characteristic changes in a direction to increase according to the relative rotation speed. As a result, the damping force can be significantly increased in the high rotation speed range.

Therefore, for example, when used as a rotary damper for a vehicle, an excessive input to the vehicle body can be reduced by rapidly increasing a damping force in response to a sudden excessive input from a road surface. (C) Damping force characteristic variable action with respect to relative rotation frequency a) When relative rotation frequency is low frequency Variable vane 50 in variable throttle means 5a, 5b
Is configured to receive the fluid pressure of the pressurized fluid chamber through the pressure receiving communication holes 4d and 4e constituting the throttle, whereby the relative rotation frequency between the annular housing 2 and the rotation shaft 1 is small. At this time, since the differential pressure ΔP is transmitted to the variable vane 50 via the pressure receiving communication holes 4d and 4e, the variable vane 50 is operated, and thereby, as described above, is constituted by the gaps 3a and 3b. The throttle channel operates in the direction of narrowing down against the urging force of the urging member 51, thereby changing the damping force in a direction in which the damping force increases in accordance with the relative rotation speed.

A) When the relative rotation frequency is high However, when the relative rotation frequency is high, the variable vane 50 is passed through the pressure receiving communication holes 4d and 4e constituting the throttle.
Since the relative rotation direction is switched before the differential pressure ΔP is transmitted, the variable vane 50 does not operate.
Even if the differential pressure ΔP is large, the gaps 3a and 3b are maintained in a state where they are not narrowed.

Therefore, the damping force characteristic can be automatically varied in response to the relative rotation frequency. For example, when the damping force characteristic is used as a vehicle rotary damper, the vibration on the sprung in the sprung resonance frequency region is obtained. Can be suppressed by the hard damping force characteristic, and the transmission of the unsprung vibration to the sprung portion in the unsprung resonance frequency region can be suppressed by the soft damping force characteristic.

As described in detail above, in the rotary damper according to the first embodiment of the present invention, the relative throttle characteristic of the gaps 3a, 3b with respect to the differential pressure ΔP in the variable throttle means 5a, 5b is changed. Since the generated damping force characteristics with respect to the rotation speed (damper operating speed) can be tuned freely, by using a high viscous fluid as the viscous fluid, a stable damping force can be generated even with a small damper with a small flow rate. And the pressure can be increased, and the degree of freedom in tuning the generated damping force characteristics is increased.

In addition, since the total cross-sectional area of the gaps 3a and 3b constituting the throttle flow path can be changed in a direction to be reduced in accordance with the relative rotation speed without using an electric actuator or the like, It is possible to avoid an increase in cost and an increase in size.

Further, the provision of the biasing member 51 for biasing the throttle flow path formed by the gaps 3a and 3b in the direction in which it expands allows the initial positioning of the variable vane 50 and the attachment of the biasing member 51. Variable vane 50 by power setting
Can be set freely. Also,
Since the urging member 51 is constituted by a leaf spring, the partition wall 23 is formed.
a, 23b and the vanes 4a, 4b can be accommodated compactly even in a limited space, thereby making it possible to avoid an increase in size.

The variable throttle means 5a, 5b are separately provided corresponding to the relative rotation direction of the annular housing 2 and the rotary shaft 1, respectively.
Since the urging forces of the urging members 51 in are different from each other,
Variable vane 50 for differential pressure ΔP depending on relative rotation direction
, The aperture amounts of the gaps 3a and 3b can be made different,
As a result, different damping force characteristics can be obtained depending on the relative rotation direction.

Further, it is possible to automatically vary the damping force characteristic in response to the relative rotation frequency without using a complicated structure.

Next, another embodiment of the present invention will be described. In the description of the other embodiments of the invention, only the differences from the first embodiment of the invention will be described, and the same reference numerals will be given to the same components, and the description thereof will be omitted.

(Embodiment 2) A rotary damper according to Embodiment 2 of the present invention is shown in FIG. 8 in an enlarged sectional view of a main part thereof and in FIG. 9 (a sectional view taken along line S9-S9 in FIG. 8). In addition, one of the two variable aperture means 5a and 5b in the first embodiment of the present invention is omitted.

By mounting the damper on the vehicle such that the counterclockwise rotation side is the extension stroke side of the damper in the drawing in which the variable throttle means 5a operates, the attenuation of the extension stroke is smaller than that of the pressure stroke. The force characteristics are improved.

Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments of the present invention, and design changes within a scope not departing from the gist of the present invention. The present invention is also included in the present invention.

For example, in the embodiment of the present invention, the case is described as an example in which it is provided on a rotation bearing portion of an upper arm of a vehicle, but the relative movement between the vehicle and any other members other than the vehicle in the rotation direction is also described. The present invention can be applied in the case of attenuation.

Further, in the embodiment of the present invention, a gap constituting the throttle flow path is formed between the housing and the vane, and the variable throttle means is provided on the vane side. And a variable throttle means may be provided on the partition wall side.

[0037]

As described above, according to the rotary damper of the first aspect of the present invention, as described above,
A throttle passage communicating between the two fluid chambers is formed by a gap formed between the housing and the vane and / or a gap formed between the rotation shaft and the partition, and the housing and the rotation shaft A gap formed between the housing and the vane and / or a rotating shaft and the partition according to a differential pressure generated between at least two fluid chambers defined by the partition and the vane due to relative rotation with the partition And a variable throttle means for narrowing a throttle flow path formed by a gap formed between the vehicle and the vehicle, for example, when used as a rotary damper for a vehicle, a sudden excessive input from a road surface. By rapidly increasing the damping force, excessive input to the vehicle body can be reduced. Further, by changing the throttle characteristic with respect to the differential pressure in the variable throttle means, it is possible to freely tune the generated damping force characteristic with respect to the damper operating speed. Therefore, by using a high-viscosity fluid as the viscous fluid, it is possible to generate a stable damping force even in a small damper having a small flow rate, and it is possible to increase the pressure and to tune the characteristic of the generated damping force. This has the effect that the degree of freedom can be increased. According to a second aspect of the present invention, in the rotary damper according to the first aspect, the variable throttle means is provided in the vane and / or the partition.
The gap formed between the housing and the vane and / or the gap formed between the rotating shaft and the partition wall by receiving the fluid pressure of the pressurized fluid chamber according to the differential pressure generated between the two fluid chambers. The variable vane that operates in the direction of narrowing the throttle channel formed by the formed gap, and the urging member that urges the variable vane in the direction that widens the throttle channel are configured as electric means. The total amount of the cross-sectional area of the throttle channel can be changed in a direction to decrease according to the relative rotation speed without using a dynamic actuator or the like, and the variable vane constituting the variable throttle means is provided with an urging member. The variable vane is biased in the direction in which the throttle flow path is widened, whereby the initial positioning of the variable vane is performed, and the operating point of the variable vane can be freely set by setting the biasing force of the biasing member. So that it is. According to a third aspect of the present invention, in the rotary damper according to the second aspect, the urging member is configured by a plate spring, so that the urging member can be compactly accommodated even in a limited space such as a partition wall or a vane. Will be able to According to a fourth aspect of the present invention, in the rotary damper according to the second or third aspect, the variable throttle means is provided separately in correspondence with a relative rotation direction between the housing and a rotation shaft. Since the urging means have different urging forces, different damping force characteristics can be obtained depending on the relative rotation direction. According to a fifth aspect of the present invention, in the rotary damper according to the second to fourth aspects, the variable vane in the variable throttle means is configured to receive the fluid pressure of the pressurized fluid chamber via the throttle. Thus, the damping force characteristic can be changed in response to the relative rotation frequency.

[Brief description of the drawings]

FIG. 1 is an overall sectional view (a sectional view taken along line S1-S1 in FIG. 2) showing a rotary damper according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line S2-S2 in FIG.

FIG. 3 is an enlarged sectional view of a main part of FIG. 2;

FIG. 4 is a sectional view taken along line S4-S4 in FIG. 3;

FIG. 5 is a sectional view taken along line S5-S5 in FIG. 3;

FIG. 6 is a sectional view and a perspective view showing a state in which the rotary damper according to the first embodiment of the present invention is mounted on a vehicle.

FIG. 7 is a graph showing a damping force characteristic with respect to a relative rotation speed.

FIG. 8 is an enlarged sectional view of a main part of a rotary damper according to a second embodiment of the present invention.

9 is a sectional view taken along line S9-S9 in FIG.

FIG. 10 is a velocity distribution diagram when the high-viscosity hydraulic oil flows in the throttle pipe.

FIG. 11 is a kinematic viscosity characteristic diagram with respect to a shear rate of a high-viscosity hydraulic oil.

FIG. 12 is an apparent velocity distribution diagram when a high-viscosity hydraulic oil flows in a throttle pipe.

FIG. 13 is a characteristic diagram of a flow coefficient with respect to a Reynolds number.

FIG. 14 is a differential pressure characteristic diagram with respect to a flow rate change.

FIG. 15 is a differential pressure characteristic diagram with respect to a flow rate change.

[Explanation of symbols]

 a1 chamber (fluid chamber) a2 chamber (fluid chamber) 1 rotating shaft 2 annular housing 3a gap (throttle channel) 3b gap (throttle channel) 4a vane 4b vane 4d pressure receiving communication hole (throttle) 4c pressure receiving communication hole (Aperture) 5a Variable aperture means 4b Variable aperture means 23a Partition wall 23b Partition wall 50 Variable vane 51 Urging member

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Junichi Emura 1370 Onna, Atsugi-shi, Kanagawa F-term in Unisia Gex Co., Ltd. (reference) 3D001 AA18 BA03 DA03 DA08 DA14 3J069 AA42 BB10 EE36

Claims (5)

[Claims] 1. A pressure chamber filled with a viscous fluid is formed between a housing and a rotation shaft rotatably supported on a shaft center portion of the housing, and a partition wall formed on the housing side. A rotary chamber in which the pressure chamber is defined as at least two fluid chambers by a vane provided on the rotating shaft side, and at least two fluid chambers defined by the partition wall and the vane are communicated with each other by a throttle channel. In the damper, a throttle passage communicating between the two fluid chambers is constituted by a gap formed between the housing and the vane and / or a gap formed between a rotating shaft and a partition. A gap formed between the housing and the vane according to a differential pressure generated between at least two fluid chambers defined by the partition and the vane due to relative rotation between the housing and a pivot shaft. / Or the rotary damper, characterized in that it comprises a variable throttle means Filter throttle channel formed by formed gap between the rotating shaft and the partition wall. 2. The variable throttling means is provided in the vane and / or the partition, and receives the fluid pressure in the pressurized fluid chamber according to a differential pressure generated between two fluid chambers. A variable vane that operates in a direction to narrow down a throttle channel formed by a gap formed between a housing and a vane and / or a gap formed between a rotation shaft and a partition; 2. The rotary damper according to claim 1, further comprising an urging member for urging the variable vane. 3. The rotary damper according to claim 2, wherein said biasing member is constituted by a leaf spring. 4. The variable throttle means are separately provided in correspondence with the relative rotation direction of the housing and the rotation shaft, and the biasing forces of the biasing means in both variable throttle means are different from each other. The rotary damper according to claim 2, wherein 5. A variable vane in said variable throttle means,
The rotary damper according to any one of claims 2 to 4, wherein the rotary damper is configured to receive the fluid pressure of the pressurized fluid chamber via a throttle.