JP4004002B2 - Rotary damper - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a rotary damper that quickly attenuates a relative vibration by giving a damping resistance to the relative vibration generated between two objects, for example, in a suspension device for vehicle body suspension in a vehicle and other vibrating bodies. .
[0002]
[Prior art]
Conventionally, this type of rotary damper is composed of a casing having a fan-shaped oil chamber partitioned by a separate block and a rotor having a vane, and the rotor is rotatably inserted into the central portion of the casing from the outside. is doing.
[0003]
The rotor divides a fan-shaped oil chamber in the casing by vanes into a pair of oil chambers that repeatedly expand and contract alternately, and these oil chambers have a predetermined attenuation with respect to the flow of oil toward each other's oil chamber. Each communicates through a passage that provides resistance.
[0004]
In this way, a predetermined damping resistance is given to the oil flow between the oil chambers that repeatedly expands and contracts in accordance with the relative rotational movement of the casing and the rotor, and the vibration generated between the two objects is quickly damped. Is widely used.
[0005]
[Problems to be solved by the invention]
In this case, when the oil chamber that repeats expansion and contraction alternately by the separate block provided in the casing and the vane of the rotor is partitioned, the seal between the two oil chambers is provided with the seal provided from the tip surface of the vane to both sides. There are two different types, a seal type that seals and a sealless type that has a passage that provides damping resistance through the vane without sealing the tip and both sides of the vane.
[0006]
However, the former seal type rotary damper has a relationship in which a seal is provided from the tip end surface of the vane to both side surfaces, and the seal is not endless, and ends at the base end portion of both side surfaces of the vane. It becomes a letter-shaped seal.
[0007]
For this reason, it is very difficult to ensure the sealing performance of the seal that ends at the base end portion of the vane, and it is difficult to maintain the processing accuracy and assembly accuracy of the portion strictly, and the damping characteristics tend to vary.
[0008]
In the latter sealless type rotary damper, instead of installing a seal on the vane, a passage is provided to provide damping resistance through the vane, and the damping resistance of the oil flowing through the passage is set to the vane tip surface and both sides. A predetermined damping resistance is provided by adding a flow resistance of oil leaking from the gap between the surfaces.
[0009]
As a result, since the size of the gap immediately affects the flow resistance of the oil passing through it, it requires a high degree of machining accuracy and assembly accuracy to manage the gap. As with the previous seal type rotary damper, It is difficult to secure the assembling property, and the attenuation characteristics are likely to vary.
[0010]
In this way, if there is any error in processing and assembly in any type of rotary damper, they immediately affect the performance as a rotary damper, resulting in performance degradation. There has been a problem that these processes and assembly require a great deal of work.
[0011]
Therefore, an object of the present invention is to provide a novel rotary damper capable of maintaining a stable damping characteristic while easily ensuring a high degree of machining and assembly accuracy.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the means of the present invention is a hollow moving shaft that is attached to a cap at one end of a casing via a seal and is provided with a rotation stopping mechanism between the cap and capable of relative displacement in the axial direction. was arranged to partition the interior of the casing inner circumferential surface in sliding contact piston body for sealing the casing against the relevant mobile shaft Rukoto provided a piston body having an outer peripheral surface to the two oil chambers, and the respectively communicated through the passage and the damping valve giving another of the oil toward the other side of the oil chamber flows against a predetermined damping resistor each oil chamber, rotatable to regulate the movement in the axial direction from the outside to the cap to the input rod screwed through a ball screw in the mobile shaft with inserting the input rod, a further sealing cap to the distal end of the moving shaft It is characterized in that the mounting shaft side cap with.
[0013]
That is, with the configuration described above, when a relative rotational movement is applied between the casing and the input rod, the piston body reciprocates through the rotation stopping mechanism together with the moving shaft through the ball screw.
[0014]
As the piston body reciprocates, oil flows through the passage between the oil chambers in the casing divided into two by the piston body, and these passages prevent relative rotation between the casing and the input rod. A damping resistance is added.
[0015]
From this, it is possible to seal between the oil chambers in the casing divided into two by providing an endless seal on the outer peripheral surface of the piston body, thereby significantly improving both workability and assembly. It will be.
[0016]
In the above, the relative rotational movement from the outside is transmitted to the input rod through, for example, a bell crank, etc., but at this time, it is decelerated by the ball screw and transmitted to the moving shaft having the piston body. The stroke of the piston body can be made small with respect to the movement of the vibration generating body, and the basic length can be remarkably shortened as compared with the conventional cylindrical shock absorber.
[0017]
In the above-described means, a suspension spring is also interposed between the cap and the piston body so as to remove the looseness of the moving shaft and the ball screw, and the damping shaft and the spacer are applied to both surfaces of the moving shaft. A body may be fitted and the damping valve, the spacer, and the piston body may be sandwiched and fixed between the shaft-side cap and the step provided on the outer periphery of the moving shaft.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
In the following, an embodiment of the present invention will be described with reference to the attached drawings. Here, a case where the present invention is applied to a suspension device for vehicle body suspension will be described. However, the present invention is not limited to this. The present invention can be applied as a rotary damper to any relative vibration object as long as it provides damping resistance to the relative vibration generated between the objects.
[0019]
In FIG. 1, a rotary damper 1 according to an embodiment of the present invention has a cap 4 screwed to one end of a casing 2 with a seal 3 interposed therebetween, and a rotation stopping mechanism 5 provided between the cap 4 and the cap 4. A hollow moving shaft 6 is disposed so as to be relatively displaceable in the axial direction.
[0020]
The moving shaft 6 is fitted with a piston body 11 having the damping valves 7 and 8 and the spacers 9 and 10 addressed to both sides, and a seal 12 as a cap seal is attached to the tip of the moving shaft 6. It is fixed by being sandwiched between the step portion 14 of the moving shaft 6 by a cap 13 as a shaft-side cap screwed through.
[0021]
On the outer circumferential surface of the piston body 11, with each other to seal 15 is interposed as a piston body for sealing sliding contact with the inner wall surface of the casing 2, the seal 12 and to each other together provided in the seal 15 and the cap 13 Thus, the inside of the casing 2 is divided into two oil chambers 16 and 17 by the piston body 11.
[0022]
A free piston 19 having a seal 18 on the outer peripheral surface is inserted into the oil chamber 17 located on the distal end side of the moving shaft 6 of the two oil chambers 16 and 17, and a part of the oil chamber 17 is freed The piston 19 partitions the gas chamber 20.
[0023]
In order to allow these two oil chambers 16 and 17 to communicate with each other with a predetermined damping resistance, in the present embodiment, two sets of passages 21 and 22 penetrating the piston body 11 are provided. ing.
[0024]
The inlet side of one set of passages 21 communicates with the oil chamber 16 through a through hole 23 provided for the damping valve 8, the outlet side to the oil chamber 17 is closed with the damping valve 7, and the other passage 22 opens the inlet side to the oil chamber 17 as it is, and closes the outlet side to the oil chamber 16 with the damping valve 8.
[0025]
An input rod 26 having a flange 25 is inserted from the outside into the casing 2 through the cap 4 with a seal 24 interposed, and the input rod 26 hits bearings 27 on both sides of the flange 25, The flange 25 is sandwiched between the cap 4 by the holding member 28 screwed into the cap 4, so that the casing 2 is rotatably inserted while restricting the axial movement from the outside.
[0026]
The input rod 26 extends from the outside through the cap 4 to the inside of the hollow moving shaft 6 having the piston body 11 while being kept sealed by the seal 24, and is screwed into the moving shaft 6 via the ball screw 29. Match.
[0027]
The bell crank 30 attached to the portion protruding to the outside of the input rod 26 is for converting one of the vertical vibrations between the vehicle body and the wheel into a rotational motion and transmitting it to the input rod 26. The spring 31 interposed between the cap 4 and the piston body 11 is a suspension spring that also serves to play back the moving shaft 6 and the ball screw 29.
[0028]
Therefore, as long as the damping resistance is given to the relative vibration generated between the two bodies other than the vehicle body and the wheel in the vehicle, not limited to the above, for example, when the relative vibration is a rotational movement from the beginning, In some cases, any other means may be used to transmit the input rod 26 as a rotational movement, and the spring 31 can be omitted if it is not necessary.
[0029]
As described above, when the rotary damper 1 is mounted between the vehicle wheel and the vehicle body using the bell crank 30 of the input rod 26 and the eye 32 of the casing 2, the force pushing the piston body 11 by the spring 31 is rotated by the ball screw 29. It is converted into power and transmitted to the input rod 26.
[0030]
The rotational force transmitted to the input rod 26 acts as a support force for supporting the vehicle body through the bell crank 30, and thus acts as a suspension spring that also serves as a backlash for the moving shaft 6 and the ball screw 29. .
[0031]
In this state, when a vertical vibration is generated between the vehicle body and the wheels and a relative rotational motion is applied between the casing 2 and the bell crank 30 and the input rod 26, the piston 11 is moved together with the moving shaft 6 by the ball screw 29. A reciprocating motion is performed through the rotation stop mechanism 5.
[0032]
As the piston body 11 reciprocates, an oil flow that flows through the passages 21 and 22 formed in the piston body 11 is generated between the oil chambers 16 and 17 in the casing 2 divided into two.
[0033]
In this case, when the vehicle body sinks, the piston body 11 moves in the direction of compressing the oil chamber 16 while pushing and shrinking the suspension spring 31, and conversely, when the vehicle body is lifted, the piston body 11 extends the suspension spring 31. While moving the oil chamber 17 in the compressing direction.
[0034]
Thereby, in the former case, the oil in the oil chamber 16 flows from the through hole 23 of the damping valve 8 to the oil chamber 17 while pushing the damping valve 7 through the passage 21 of the piston body 11.
[0035]
Further, in the latter case, the oil in the oil chamber 17 flows from the passage 22 of the piston body 11 to the damping valve 8 and flows into the oil chamber 16, and in this way, a predetermined damping resistance is obtained by the damping valves 7 and 8. To quickly attenuate the vertical vibration between the vehicle body and the wheels.
[0036]
In this case, the volume change of the oil corresponding to the intrusion and withdrawal volume of the moving rod 6 with the piston body 11 into the oil chambers 16 and 17 in the casing 2 is caused by the expansion and contraction of the gas chamber 20. Compensated by 19 movements.
[0037]
In addition to the above, the gas chamber 20 functions to prevent the occurrence of cavitation by keeping the oil in the oil chambers 16 and 17 at a high pressure, and the oil pressure change due to expansion and contraction of the oil chambers 16 and 17 due to heat generation, Alternatively, it also serves to compensate for changes in oil pressure due to expansion and contraction of the oil itself.
[0038]
【The invention's effect】
As described above, according to the first aspect of the present invention, the cap is attached to one end of the casing via the seal, and the rotation shaft is provided between the cap and the hollow movable shaft that is relatively displaceable in the axial direction. was arranged to partition the interior of the casing inner circumferential surface in sliding contact piston body for sealing the casing against the relevant mobile shaft Rukoto provided a piston body having an outer peripheral surface to the two oil chambers, and the respectively communicated through the passage and the damping valve giving another of the oil toward the other side of the oil chamber flows against a predetermined damping resistor each oil chamber, rotatable to regulate the movement in the axial direction from the outside to the cap through a ball screw to the input rod in said moving shaft while inserting the input rod screwed further through the cap for sealing the front end of the moving shaft By fitted with shaft-side cap, you can achieve the following effects.
First, since the relative rotational motion to the input rod from the outside is decelerated by the ball screw and transmitted to the moving shaft having the piston body, the stroke of the piston body with respect to the movement of the vibration generating body. As a result, the basic length can be remarkably shortened as compared with the conventional cylindrical shock absorber.
Second, the sealing can become between the oil chamber in the casing is divided into two, thus, it is possible to maintain a stable damping characteristic as the rotary damper, significantly improve both processability and assembling property be able to.
[0040]
According to the second aspect of the present invention, since the suspension spring that also serves as the backlash of the moving shaft and the ball screw is interposed between the cap and the piston body , the overall configuration is further simplified and reduced in size. Can be configured.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view showing an embodiment of a rotary damper according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotary damper 2 Casing 3 Seal 4 Cap 5 Anti-rotation mechanism 6 Moving shaft 7, 8 Damping valve 11 Piston body 12 Seal (cap seal)
13 Cap (Shaft side cap)
14 Step 15 seal (Piston body seal)
16, 17 Oil chamber 18 Free piston seal 19 Free piston 20 Gas chamber 21, 22 Passage for damping resistance 23 Through hole 24 Input rod seal 25 鍔 26 Input rod 27 Bearing 29 Ball screw 31 Spring for suspension

Claims (2)

Replace the cap via the seal at one end of the casing, arranged subjected to rotation stopping mechanism to axially displaceable relative to the hollow movement shaft between the caps, the inner periphery of the casing against the corresponding mobile shaft the interior of the casing at Rukoto provided a piston body provided with a surface in sliding contact piston member for sealing the outer peripheral surface is divided into two oil chambers, and oil toward the oil chamber of the other party mutually each oil chamber flow against each communicated through the passage and the damping valve providing a predetermined attenuation resistor, the moving shaft and the input rod while inserting the rotatable input rod to regulate the movement in the axial direction from the outside to the cap that screwed through a ball screw, and further fitted with a shaft-side cap through a cap for sealing the front end of the moving shaft within A rotary damper for the butterflies. A suspension spring that doubles the movement shaft and ball screw is interposed between the cap and the piston body. The piston body is fitted to the movement shaft by placing the damping valve and spacer on both sides. The rotary damper according to claim 1, wherein the damping valve, the spacer, and the piston body are fixed by being sandwiched between a shaft-side cap and a step portion provided on the outer periphery of the moving shaft .

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