WO2014188889A1

WO2014188889A1 - Bump stop

Info

Publication number: WO2014188889A1
Application number: PCT/JP2014/062497
Authority: WO
Inventors: 一輝田中
Original assignee: Nok株式会社
Priority date: 2013-05-22
Filing date: 2014-05-09
Publication date: 2014-11-27
Also published as: JP2016136027A

Abstract

Provided is a bump stop capable of smoothing the increase in load as the amount of compression increases. A bump stop (100), the outer circumferential surface of which is configured in a bellows shape and the multiple peak sections (first peak section (111), second peak section (112), third peak section (113)) and valley sections (first valley section (121), second valley section (122), third valley section (123)) in the bellows shape are configured so that the respective diameters decrease towards the tip, the bump stop being characterized in that when the diameter of a peak section is X and the diameter of the adjacent valley section on the base end side of said peak section is Y, Y÷X is set so as to decrease from the tip end toward the base end.

Description

Bump stopper

The present invention relates to a bump stopper for absorbing an impact.

Bump stoppers are provided on automobile suspensions to absorb shocks when the car body sinks. The bump stopper is attached to the shock absorber so as to absorb the impact by being compressed.

A conventional bump stopper will be described with reference to FIGS. FIG. 5 is a schematic cross-sectional view showing a state when the bump stopper according to the conventional example is compressed. FIG. 5A shows a state where the bump stopper is not compressed, and FIGS. 5B, 5C, and 5D are schematic sectional views showing the state in which the amount of compression increases in this order. Show. FIG. 5 shows a half cross-sectional view of a cross section obtained by cutting the bump stopper along a plane including the central axis thereof.

The bump stopper 500 has an outer peripheral surface configured in a bellows shape so that the deformation state when compressed is stabilized, and a plurality of peaks and valleys are formed on the outer periphery. Hereinafter, for the sake of convenience, the first peak portion 511, the first valley portion 521, the second peak portion 512, the second valley portion 522, the third peak portion 513, and the third valley portion 523 are referred to in order from the tip side.

The bump stopper 500 is made of polyurethane foam, and can be obtained by mold molding such as injection molding. During molding, when the molding material is filled into the mold cavity, the molding material is filled from the rear end side toward the front end side. Therefore, in consideration of material fluidity at the time of filling, the plurality of crests and troughs are configured such that the diameter becomes smaller toward the tip side. That is, if the diameter of the first peak 511 is D11, the diameter of the second peak 512 is D12, and the diameter of the third peak 513 is D13, then D11 <D12 <D13 is satisfied. Further, when the diameter of the first valley portion 521 is D21, the diameter of the second valley portion 522 is D22, and the diameter of the third valley portion 523 is D23, D21 <D22 <D23 is satisfied. Therefore, in the valley, the thickness of the site of the first valley 521 is the thinnest, and the thickness of the site of the third valley 523 is the thickest. Along with this, when compared at each valley, the rigidity of the site of the first valley 521 is the lowest, and the rigidity of the site of the third valley 523 is the highest.

Therefore, when the bump stopper 500 is compressed, first, the first valley portion 521 is deformed so as to be compressed (see FIG. 5B), and then the second valley portion 522 is compressed. Deformation (see (c) of the figure). And finally, it deform | transforms so that the site | part of the 3rd trough part 523 may compress (refer the figure (d)). As described above, the bump stopper 500 according to the conventional example is deformed so that the plurality of valley portions are sequentially compressed.

Here, the relationship between the compression amount of the bump stopper 500 and the load (load necessary for compression) will be described with reference to FIG. FIG. 6 is a graph schematically showing the relationship between the compression amount and the load in the bump stopper 500.

In the process of deforming so that the portion of the first valley portion 521 is compressed, the spring constant in the compression direction of the entire bump stopper 500 is constant or gradually increases, so that the load is substantially linear as the compression amount increases. (L11 in the graph). And when the site | part of the 2nd trough part 522 begins to compress, the said spring constant becomes low. Therefore, the ratio of the load increase with respect to the increase in the compression amount decreases (L12 in the graph). Thereafter, until the portion of the third valley portion 523 is compressed, the spring constant increases again, and the rate of increase in the load with respect to the increase in the compression amount increases (L13 in the graph). And when the site | part of the 3rd trough part 523 begins to compress, the said spring constant will become low and the ratio of the increase in load with respect to the increase in compression amount will fall (L14 in a graph).

As described above, the bump stopper 500 according to the conventional example is deformed so that the plurality of valley portions are sequentially compressed. For this reason, a phenomenon occurs in which the spring constant is switched stepwise, and the load does not increase smoothly as the compression amount increases, as shown in the graph of FIG. From the viewpoint of absorbing shock, this means that the compression load on the bump stopper 500 does not change smoothly during the process of compressing the bump stopper 500. Therefore, this is a cause of adversely affecting the steering performance of the vehicle.

FIG. 7 is a graph showing test results of changes in the spring constant with respect to the compression amount in the bump stopper 500 according to the conventional example. As can be seen from this graph, a phenomenon occurs in which the spring constant is switched in stages. The region L21 in FIG. 7 corresponds to L11 in the graph of FIG. 6, the region L22 in FIG. 7 corresponds to L12 in the graph of FIG. 6, and the region L23 in FIG. 6 corresponds to L13 in the graph of FIG. 6, and a region L24 in FIG. 7 corresponds to L14 in the graph of FIG.

In addition, if all the diameters of a trough part are made small, it can suppress that it deform | transforms so that the site | part of a some trough part may compress in order. However, in this case, the thickness of the valley portion becomes thin, and the portion through which the molding material passes in the molding die becomes narrow. For this reason, the molding material is not sufficiently filled and causes molding defects, and thus such measures cannot be taken.

JP 2006-38022 A JP 2003-184938 A

An object of the present invention is to provide a bump stopper capable of smoothing an increase in load with respect to an increase in compression amount.

The present invention employs the following means in order to solve the above problems.

That is, the bump stopper of the present invention is
The outer peripheral surface is configured in a bellows shape, and the plurality of peaks and valleys in the bellows shape are each configured as a bump stopper configured such that the diameter becomes smaller toward the tip side.
When the diameter of the peak is X and the diameter of the valley adjacent to the rear end of the peak is Y, Y ÷ X is set so as to decrease from the front end toward the rear end. It is characterized by being.

According to the present invention, each of the plurality of peaks and valleys in the bellows shape is configured to have a smaller diameter toward the tip side. When compressing, it deform | transforms so that a trough may compress in order toward the rear end side from the front end side. However, in the present invention, when the diameter of the peak portion is X and the diameter of the valley portion adjacent to the rear end side of the peak portion is Y, Y ÷ X increases from the front end side toward the rear end side. It is set to be smaller. Therefore, the nonuniformity of rigidity in each valley is reduced. Thereby, the compression timing in each valley part can be brought close (preferably simultaneously), and the change of the spring constant with respect to the compression amount of the bump stopper can be suppressed. Therefore, an increase in load with respect to an increase in the compression amount of the bump stopper can be smoothed.

Here, in the bellows shape on the outer peripheral surface, in order from the front end side to the rear end side, the first peak portion, the first valley portion adjacent to the first peak portion, and the second peak portion adjacent to the first valley portion. , Having a second valley adjacent to the second peak, a third peak adjacent to the second peak, and a third valley adjacent to the third peak,
The diameter of the first crest is X1, the diameter of the second crest is X2, the diameter of the third crest is X3, the diameter of the first trough is Y1, the diameter of the second trough is Y2, the diameter of the third trough When the diameter is Y3,
0.90 <Y1 ÷ X1 <0.95
0.75 <Y2 ÷ X2 <0.80
0.70 <Y3 ÷ X3 <0.75
It is good to satisfy all of the above.

As described above, according to the present invention, it is possible to smoothly increase the load with respect to the increase in the compression amount of the bump stopper.

FIG. 1 is a partially broken sectional view of a bump stopper according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a state when the bump stopper according to the embodiment of the present invention is compressed. FIG. 3 is a graph schematically showing the relationship between the compression amount and the load in the bump stopper according to the embodiment of the present invention. FIG. 4 is a graph showing test results of changes in the spring constant with respect to the compression amount in the bump stopper according to the embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a state when the bump stopper according to the conventional example is compressed. FIG. 6 is a graph schematically showing the relationship between the compression amount and the load in the bump stopper according to the conventional example. FIG. 7 is a graph showing test results of changes in the spring constant with respect to the compression amount in the bump stopper according to the conventional example.

DETAILED DESCRIPTION Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(Example)
A bump stopper according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, a case where a bump stopper is attached to a shock absorber provided on a suspension of an automobile will be described as an example.

<Application example of bump stopper>
In particular, with reference to FIG. 2, an application example of the bump stopper according to the embodiment of the present invention will be described. FIG. 2 is a schematic cross-sectional view showing the vicinity of a bump stopper in an automobile suspension. 2A shows a state in which the bump stopper is not compressed, and FIGS. 2B and 2C show a state in which the compression amount is increased in this order in schematic sectional views. . FIG. 2 shows a partial cross-sectional view of a cross section obtained by cutting the bump stopper along a plane including the central axis.

The suspension is provided with a shock absorber 200 for suppressing vibration of the vehicle body. The shock absorber 200 is a hydraulic damper type shock absorber including a piston rod 210 and a cylinder 220. When the vehicle body sinks, the piston rod 210 moves toward the inside of the cylinder 220. That is, the shock absorber 200 contracts, and the shock can be absorbed by the hydraulic resistance.

Further, a support member 230 is fixed to the piston rod 210, and the bump stopper 100 is attached between the support member 230 and the end surface 221 of the cylinder 220. The bump stopper 100 is an annular member made of polyurethane foam, and is attached to the shock absorber 200 so that the piston rod 210 is inserted into the inner peripheral side thereof. The bump stopper 100 is disposed such that the end surface 140 on the rear end side contacts the support member 230. The bump stopper 100 may or may not be fixed to the support member 230.

With the above configuration, when the vehicle body sinks and the shock absorber 200 contracts, the bump stopper 100 moves toward the cylinder 220 as the piston rod 210 moves into the cylinder 220. When the shock absorber 200 is contracted, the tip 130 of the bump stopper collides with the end surface 221 of the cylinder 220. Thereby, since the bump stopper 100 is compressed, an impact can be absorbed.

<Bump stopper>
In particular, with reference to FIG. 1, the bump stopper 100 according to the present embodiment will be described in more detail. The bump stopper 100 according to the present embodiment has an outer peripheral surface configured in a bellows shape so that a deformation state when compressed is stabilized, and a plurality of (annular) peaks and (annular) are formed on the outer periphery. A valley is formed. In the bump stopper 100 according to the present embodiment, both the inner peripheral surface and the outer peripheral surface have a bellows shape. Hereinafter, for the sake of convenience, the first peak 111, the first valley 121, the second peak 112, the second valley 122, and the third peak 113 are sequentially arranged from the front end side with respect to the plurality of peaks and valleys on the outer peripheral side. , Referred to as the third valley portion 123. 1st peak 111 and 1st valley 121, 1st valley 121 and 2nd peak 112, 2nd peak 112 and 2nd valley 122, 2nd valley 122 and 3rd peak 113, 3rd The mountain portion 113 and the third valley portion 123 are adjacent to each other. The tip side is the side that collides with the end surface 221 of the cylinder 220 as described above.

In the bump stopper 100 according to the present embodiment, the plurality of crests and troughs in the bellows shape are configured such that the diameter becomes smaller toward the tip side. This is because the bump stopper 100 is made of foamed polyurethane, and the viscosity of the molding material supplied into the mold is relatively high. That is, the bump stopper 100 is molded (for example, molding by injection molding) after filling the cavity in the mold with the molding material. In the material filling process at the time of molding, the molding material is filled from the rear end side (of the bump stopper 100) toward the front end side. That is, the molding die is installed so that the front end side of the bump stopper 100 obtained by molding is downward, and the molding material falling by gravity is filled into the cavity from the rear end side toward the front end side. It will be. Therefore, in consideration of the fluidity of the molding material at the time of filling, the diameter of the valley portion on the rear end side (that is, the upper side in the mold) is increased so that the flow of the molding material is not hindered in the cavity. Yes.

In the bump stopper 100 according to the present embodiment, when the diameter of the peak is X and the diameter of the valley adjacent to the rear end of the peak is Y, Y ÷ X is from the tip side. It is set so as to become smaller toward the rear end side.

Hereinafter, a more specific example will be described. As shown in FIG. 1, the diameter of the first peak 111 is X1, the diameter of the second peak 112 is X2, the diameter of the third peak 113 is X3, the diameter of the first valley 121 is Y1, and the second valley. The diameter of the portion 122 is Y2, and the diameter of the third valley portion 123 is Y3.

At this time,
0.90 <Y1 ÷ X1 <0.95 (Formula 1)
0.75 <Y2 ÷ X2 <0.80 (Formula 2)
0.70 <Y3 ÷ X3 <0.75 (Formula 3)
It is comprised so that all of these may be satisfy | filled.

<Excellent points of the bump stopper according to this embodiment>
In particular, with reference to FIGS. 3 and 4, the excellent point of the bump stopper 100 according to the present embodiment will be described.

The bump stopper 100 according to the present embodiment is configured such that the diameters of the plurality of crests and troughs in the bellows shape on the outer peripheral surface become smaller toward the tip side. Therefore, the rigidity is inherently lower toward the front end side, and when the bump stopper 100 is compressed, the trough portion is deformed in order from the front end side toward the rear end side.

However, in the bump stopper 100 according to the present embodiment, when the diameter of the crest is X and the diameter of the valley adjacent to the rear end side of this crest is Y, Y ÷ X is from the front end side. It is set so as to become smaller toward the rear end side. Therefore, the nonuniformity of rigidity in each valley is reduced. Thereby, the timing of compression in each trough part can be approximated. By setting Y ÷ X, the compression timings in the valleys can be made substantially simultaneously.

FIG. 2B shows a state in which the first valley portion 121, the second valley portion 122 portion, and the third valley portion 123 portion have started to be compressed almost simultaneously, and FIG. The state when the amount of compression of each part becomes large is shown.

Thus, the compression timing of each valley part can be approached (or can be made substantially simultaneously). Thereby, it is possible to suppress (or eliminate) the spring constant in the compression direction of the entire bump stopper 100 from being switched in a stepwise manner in the process in which the bump stopper 100 is compressed. Therefore, as shown in the graph of FIG. 3, the bump stopper 100 according to the present embodiment has a characteristic that the load (the load necessary for the compression) increases smoothly as the compression amount increases. From the viewpoint of absorbing the impact, this means that the compressive load on the bump stopper 100 changes smoothly in the process in which the bump stopper 100 is compressed. Therefore, it is possible to suppress adverse effects on the steering performance of the vehicle.

As a more preferable example, as described above, it may be configured to satisfy all of the above (Formula 1), (Formula 2), and (Formula 3). As a result, the spring constant in the compression direction of the entire bump stopper 100 is switched step by step while maintaining the moldability (that is, without causing trouble when filling the molding die with the molding material). Can be suppressed. FIG. 4 is a graph showing a test result of changes in the spring constant with respect to the compression amount in the bump stopper 100 configured to satisfy all of the above (Expression 1), (Expression 2), and (Expression 3). As can be seen from this graph, it is possible to prevent the spring constant in the compression direction of the entire bump stopper 100 from being switched stepwise.

(Other)
In the above embodiment, a configuration in which three valleys are provided on the outer periphery of the bump stopper 100 is shown. However, in the present invention, a bump stopper provided with two valleys and four or more valleys are provided. The present invention can also be applied to the existing bump stopper. Even in this case, as described above, from the viewpoint of molding, the diameter (the outer diameter of the bottom of the valley) is configured to be smaller toward the tip of the valley.

DESCRIPTION OF SYMBOLS 100 Bump stopper 111 1st peak part 112 2nd peak part 113 3rd peak part 121 1st trough part 122 2nd trough part 123 3rd trough part 130 Tip 140 End surface 200 Shock absorber 210 Piston rod 220 Cylinder 221 End surface 230 Support member

Claims

The outer peripheral surface is configured in a bellows shape, and the plurality of peaks and valleys in the bellows shape are each configured as a bump stopper configured such that the diameter becomes smaller toward the tip side.
When the diameter of the peak is X and the diameter of the valley adjacent to the rear end of the peak is Y, Y ÷ X is set so as to decrease from the front end toward the rear end. A bump stopper characterized by having
In the bellows shape on the outer peripheral surface, in order from the front end side to the rear end side, the first peak, the first valley adjacent to the first peak, the second peak adjacent to the first valley, and the second A second valley adjacent to the peak, a third peak adjacent to the second valley, and a third valley adjacent to the third peak;
The diameter of the first crest is X1, the diameter of the second crest is X2, the diameter of the third crest is X3, the diameter of the first trough is Y1, the diameter of the second trough is Y2, the diameter of the third trough When the diameter is Y3,
0.90 <Y1 ÷ X1 <0.95
0.75 <Y2 ÷ X2 <0.80
0.70 <Y3 ÷ X3 <0.75
The bump stopper according to claim 1, wherein all of the above are satisfied.