JP6540262B2 - Bump stopper - Google Patents

Description

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

  The suspension of the car is provided with a bump stopper to absorb an impact when the car body is sunk. The bump stopper is attached to the shock absorber so as to absorb an impact by being compressed.

  A bump stopper according to a conventional example will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic cross-sectional view showing the state of the bump stopper 600 according to the prior art at the time of compression. In FIG. 6, the left side shows the state in which the bump stopper 600 is not compressed, and the state in which the amount of compression increases toward the right side is a schematic sectional view (a cross section cut along a plane including the central axis) Figure). The shock absorber is a hydraulic damper type shock absorber comprising a piston rod 200 and a cylinder 300. When the vehicle body is sunk, the piston rod 200 moves toward the inside of the cylinder 300 together with the support member 400 and the bump stopper 600. Then, the tip end of the bump stopper 600 collides with the end face of the cylinder 300 and the bump stopper 600 is compressed to absorb the impact.

  The bump stopper 600 has an outer peripheral surface formed in a bellows shape so that a deformed state at the time of compression is stabilized, and a plurality of peaks and valleys are formed on the outer peripheral surface. Hereinafter, for convenience, the first peak portion 611, the first valley portion 621, the second peak portion 612, the second valley portion 622, and the third peak portion 613 are referred to in order from the tip side. Further, on the inner circumferential surface, an annular recess is provided on the inner side of the first peak 611 and the second peak 612, respectively. Hereinafter, for convenience, the first annular recess 631 and the second annular recess 632 will be referred to.

  The bump stopper 600 is made of foamed polyurethane and is obtained by molding such as injection molding. Then, at the time of molding, when the molding material is filled in the cavity of the mold, the molding material is filled from the rear end side toward the front end side. Therefore, in consideration of the material flowability at the time of filling, the plurality of peaks and valleys are configured such that the diameter decreases toward the tip end. Accordingly, in the portion where the valley portion is provided, the thickness of the portion of the first valley portion 621 is thin, and the thickness of the portion of the second valley portion 622 is large.

  Therefore, when the bump stopper 600 is compressed, the portion of the first valley portion 621 is first deformed so as to be compressed (see the middle diagram in FIG. 6), and then the portion of the second valley portion 622 is compressed. (See the figure on the right of the figure). Here, with reference to FIG. 7, the relationship between the amount of compression of the bump stopper 600 and the spring constant (spring constant when the entire bump stopper is considered as a spring) will be described. FIG. 7 is a graph schematically showing the relationship between the amount of compression and the spring constant in the bump stopper 600 according to the conventional example.

  When the bump stopper 600 is impacted and begins to compress, the spring constant increases. Then, when the first valley portion 621 starts to be deformed, the spring constant decreases. A in the graph corresponds to the timing at which the first valley portion 621 starts to be deformed. And if the 1st peak part 611 and the 2nd peak part 612 contact, spring constant will increase again. B in the graph corresponds to the timing when the first peak 611 and the second peak 612 are in close contact. Thereafter, when the second valley portion 622 starts to deform, the spring constant decreases again. C in the graph corresponds to the timing at which the second valley portion 622 starts to be deformed. Then, when the second peak portion 612 and the third peak portion 613 are in close contact with each other, the spring constant increases again. D in the graph corresponds to the timing at which the second peak 612 and the third peak 613 are in close contact.

  As described above, in the bump stopper 600 according to the conventional example, since the portions of the plurality of valleys are deformed so as to be compressed sequentially, a phenomenon occurs in which the above-mentioned spring constant is switched stepwise. That is, with an increase in the amount of compression of the bump stopper 600, the load required to compress the bump stopper 600 does not smoothly increase. From the viewpoint of shock absorption, in the process of compressing the bump stopper 600, the compressive load on the bump stopper 600 does not change smoothly. Therefore, it causes an adverse effect on the steering stability of the vehicle.

JP, 2013-170670, A

  An object of the present invention is to provide a bump stopper which can smooth change in spring constant with respect to increase in compression amount.

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

That is, the bump stopper of the present invention is
The bump stopper is configured such that the outer peripheral surface is formed in a bellows shape, and the plurality of peaks and valleys in the bellows shape are configured such that the diameter decreases toward the tip end side,
Inner peripheral surface side, the plurality of respective annular recess on the inner side of the valley is formed Rutotomoni,
In the annular recess respectively formed inside the plurality of valleys, the inner diameter of the portion having the largest diameter among the annular recesses is set to be smaller as the annular recess on the tip end side .

  According to the present invention, since the plurality of peak portions and valley portions in the bellows shape on the outer peripheral surface side are configured to decrease in diameter toward the tip end, the rigidity is inherently lower toward the tip end, When the bump stopper compresses, the valley portion is deformed so as to be compressed in order from the front end side to the rear end side. However, in the present invention, an annular recess is formed on the inner circumferential surface side and inside the plurality of valleys. Therefore, the uneven rigidity of the portion where the respective valleys are provided is reduced. This makes it possible to approximate (preferably simultaneously) the timing of compression in each valley, and to suppress the change in the spring constant (spring constant when the entire bump stopper is considered as a spring) with respect to the amount of compression of the bump stopper. Can.

And in the annular recess respectively formed inside the plurality of valleys, the inner diameter of the portion having the largest diameter among the annular recesses is set to be smaller as the annular recess on the tip end side, so the rigidity in each valley is Can be suitably reduced.

  The thickness between the valley on the outer peripheral surface side and the annular recess on the inner peripheral surface side inside the valley may be set to 5 mm or more.

  Thereby, molding defects can be suppressed.

  In a cross section obtained by cutting the bump stopper at a plane including the central axis of the bump stopper, the annular recess formed on the inner side of the plurality of valleys is such that both sides of the recess open from the bottom of the recess toward the inner circumferential surface It is preferable that the opening angle be set to 90.degree. Or more.

  As a result, after molding, it is possible to enhance the releasability at the time of taking out the bump stopper which is a molded article from the mold.

  As described above, according to the present invention, it is possible to make the change of the spring constant smooth with respect to the increase of the compression amount.

FIG. 1 is a schematic cross-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 of the bump stopper according to the embodiment of the present invention at the time of compression. FIG. 3 is a schematic cross-sectional view of a bump stopper according to a comparative example of the present invention. FIG. 4 is a schematic cross-sectional view showing the bump stopper according to the comparative example of the present invention at the time of compression. FIG. 5 is a graph showing the change of the spring constant with respect to the amount of compression in the bump stopper according to the example of the present invention and the comparative example. FIG. 6 is a schematic cross-sectional view showing the state of the bump stopper according to the prior art at the time of compression. FIG. 7 is a graph schematically showing the relationship between the amount of compression and the spring constant in the bump stopper according to the conventional example.

  Hereinafter, with reference to the drawings, modes for carrying out the present invention will be exemplarily described in detail based on examples. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified. .

(Example)
A bump stopper according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In this embodiment, the case where a bump stopper is attached to a shock absorber provided on a suspension of a vehicle will be described as an example.

<Example of application 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 attached to a suspension of a vehicle. In FIG. 2, the left side shows the state in which the bump stopper is not compressed, and the right side shows the state in which the amount of compression of the bump stopper has reached a predetermined amount. In each of the drawings, a schematic cross-sectional view (a cross-sectional view of a part of a cross-section cut along a plane including the central axis) is shown.

  The suspension is provided with a shock absorber to suppress the vibration of the vehicle body. This shock absorber is a hydraulic damper type shock absorber comprising a piston rod 200 and a cylinder 300. When the vehicle body sinks, the piston rod 200 moves toward the inside of the cylinder 300. That is, the shock absorber is contracted and the hydraulic resistance can absorb the impact.

Further, a support member 400 is fixed to the piston rod 200, and the bump stopper 100 is attached between the support member 400 and the end surface of the cylinder 300. The bump stopper 100 is an annular member made of foamed polyurethane, and is attached to the shock absorber such that the piston rod 200 is inserted on the inner peripheral side thereof. The bump stopper 100 is disposed such that the end surface 160 on the rear end side abuts on the support member 400. The bump stopper 100 may or may not be fixed to the support member 400.

  With the above configuration, as the vehicle body sinks and the shock absorber contracts, as the piston rod 200 moves to the inside of the cylinder 300, the bump stopper 100 also moves to the cylinder 300 side. Then, when the shock absorber is contracted, the tip 150 of the bump stopper collides with the end face of the cylinder 300. As a result, the bump stopper 100 is compressed, so that the 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. FIG. 1 is a schematic cross-sectional view of a bump stopper 100 according to an embodiment of the present invention. In FIG. 1, a cross-sectional view in which the bump stopper 100 is cut along a plane including the central axis of the bump stopper 100 is shown. Further, a partially enlarged cross-sectional view is also shown for the circled portion in the drawing. The bump stopper 100 has a rotationally symmetrical shape.

  In the bump stopper 100 according to the present embodiment, the outer peripheral surface is formed in a bellows shape so that a deformed state when compressed is stabilized, and a plurality of (annular) peak portions and (an annular ) A valley is formed. Hereinafter, for the sake of convenience, the first peak 111, the first valley 121, the second peak 112, the second peak 122, the third peak 113, the third peak 123, and the fourth peak 114 in order from the tip side. It is called. The tip end side is a side that collides with the end face of the cylinder 300 as described above.

  In the bump stopper 100 according to the present embodiment, the plurality of peak portions and valley portions in the bellows shape are configured such that the diameter decreases toward the tip end side. This is because the bump stopper 100 is made of foamed polyurethane, and the viscosity of the material is relatively high when the molding material is supplied into the mold. That is, the bump stopper 100 is molded (for example, molded by injection molding) after the cavity in the mold is filled with the molding material. In the material filling step at the time of molding, the molding material is filled from the rear end side (of the bump stopper 100) to the front end side. That is, the molding die is installed so that the tip side of the bump stopper 100 obtained by molding is downward, and the molding material dropped by gravity is filled in the cavity from the rear end side toward the tip side. It will be. Therefore, in consideration of the flowability of the molding material at the time of filling, the diameter of the valley on the rear end side (that is, the upper side in the mold) is enlarged so that the flow of the molding material is not impeded in the cavity. There is.

  Further, on the inner peripheral surface side of the bump stopper 100 according to the present embodiment, an annular recess is formed on the inside of several peak portions on the tip end side among the plurality of peak portions. More specifically, annular recesses are formed in the first peak portion 111, the second peak portion 112, and the third peak portion 113, respectively. Hereinafter, for convenience, the inner annular recess of the first peak 111 is referred to as a first annular recess 131, and the inner annular recess of the second peak 112 is referred to as a second annular recess 132. The annular recess is referred to as a third annular recess 133.

  In addition, on the inner circumferential surface side of the bump stopper 100 according to the present embodiment, an annular recess is formed inside the plurality of valleys (the first valley 121, the second valley 122, and the third valley 123). It is done. Hereinafter, for convenience, the inner annular recess of the first valley 121 is referred to as a fourth annular recess 141, the inner annular recess of the second valley 122 is referred to as a fifth annular recess 142, and the inner recess of the third valley 123 is referred to. The annular recess is referred to as a sixth annular recess 143.

Here, the annular recess (the fourth annular recess 141, the fifth annular recess 142, and the sixth) respectively formed inside the plurality of valleys (the first valley 121, the second valley 122, and the third valley 123). Annular recess 1
In 43), the inner diameter of the portion having the largest diameter among the annular recesses is set to be smaller as the annular recess on the tip end side. That is, the inner diameter of the largest diameter portion of the fourth annular recess 141 is D1, the inner diameter of the largest diameter portion of the fifth annular recess 142 is D2, and the largest diameter portion of the sixth annular recess 143 The inner diameter of is D3 (see FIG. 1). At this time, D1 <D2 <D3 is satisfied.

  Further, the thickness between the valley on the outer peripheral surface side and the annular recess on the inner peripheral surface side inside the valley is set to 5 mm or more. That is, the thickness T between the first valley 121 and the fourth annular recess 141 (see the enlarged sectional view in FIG. 1), the thickness between the second valley 122 and the fifth annular recess 142, and The thickness between the third valley portion 123 and the sixth annular recess 143 is set to 5 mm or more. As a result, molding defects when molding the bump stopper 100 can be suppressed.

  Furthermore, in the present embodiment, a plurality of valleys (the first valley 121, the second valley 122, and the third valley 123) in the cross section obtained by cutting the bump stopper 100 along a plane including the central axis of the bump stopper 100. The annular recess (the fourth annular recess 141, the fifth annular recess 142, and the sixth annular recess 143) respectively formed on the inner side of the recess is formed so that both sides of the recess open from the bottom of the recess toward the inner peripheral surface side. ing. The opening angle α is set to be 90 ° or more (see the enlarged cross-sectional view in FIG. 1). Thereby, after molding, the releasability at the time of taking out bump stopper 100 which is a cast from a metallic mold can be improved.

<Excellent points of the bump stopper according to the present embodiment>
According to the bump stopper 100 according to the present embodiment, since the plurality of peak portions and valley portions in the bellows shape on the outer peripheral surface side are configured to decrease in diameter toward the tip end side, the tip end side is intrinsically The rigidity is lower, and when the bump stopper 100 is compressed, the valley portion is deformed so as to be compressed in order from the front end side to the rear end side.

  However, on the inner peripheral surface side of the bump stopper 100 according to the present embodiment, annular concave portions (fourth to fourth ones) are provided inside the plurality of valleys (the first valley 121, the second valley 122, and the third valley 123). An annular recess 141, a fifth annular recess 142 and a sixth annular recess 143) are formed. Therefore, the uneven rigidity of the portion where the respective valleys are provided is reduced. That is, as in the conventional example, in the case where the annular recess is not formed inside the plurality of valleys, the thickness of the portion where the valleys are provided is thinner toward the tip end and the rigidity is lower. . On the other hand, an annular recess (the fourth annular recess 141, the fifth annular recess 142, and the sixth annular recess 143) is formed on the inner peripheral surface side of the bump stopper 100 on the inner side of each valley. It is possible to adjust the rigidity of the portion where each valley is provided, and it is possible to reduce the uneven rigidity of each portion. This makes it possible to approximate (preferably simultaneously) the timing of compression in each valley, and to suppress the change in the spring constant (spring constant when the entire bump stopper is considered as a spring) with respect to the amount of compression of the bump stopper. Can. The respective valleys are provided by adjusting the depths of the plurality of valleys (the first valley 121, the second valley 122, and the third valley 123) on the outer peripheral surface side of the bump stopper 100. It is also conceivable to adjust the rigidity of the part. However, as the depth of the valleys is increased, gas may enter at the time of molding to cause molding defects, or the releasability may be deteriorated. Therefore, there is a limit to adjusting the depth of the valley.

  Here, in the present embodiment, annular concave portions (fourth annular concave portions 141 and fifth portions) formed on the inner side of the plurality of valley portions (the first valley portion 121, the second valley portion 122, and the third valley portion 123). In the annular recess 142 and the sixth annular recess 143), the inner diameter of the portion having the largest diameter among the annular recesses is set to be smaller as the annular recess on the distal end side. That is, in FIG. 1, it is set to satisfy D1 <D2 <D3. Thereby, the rigidity in each valley can be adjusted, and the unevenness in the rigidity in each valley can be suitably reduced.

  As described above, since the compression timing of each valley portion can be made close (or nearly simultaneously), the spring constant of the entire bump stopper 100 in the compression direction is in the process of compressing the bump stopper 100. Stepwise switching can be suppressed (or eliminated). Therefore, in the bump stopper 100 according to the present embodiment, the load (load required for compression) smoothly increases with an increase in the amount of compression. This means that the compressive load on the bump stopper 100 changes smoothly in the process of compression of the bump stopper 100 from the viewpoint of shock absorption. Therefore, it is possible to suppress that the steering performance of the vehicle is adversely affected.

  Hereinafter, with respect to the bump stopper 100 according to the present embodiment and the bump stopper 500 according to the comparative example (conventional example), the result of analysis of the change of the spring constant with respect to the compression amount by FEM analysis will be described.

  FIG. 3 is a schematic cross-sectional view of a bump stopper 500 according to a comparative example of the present invention. The bump stopper 500 according to the comparative example is the same as the bump stopper 100 according to the present embodiment except that the fourth annular recess 141, the fifth annular recess 142 and the sixth annular recess 143 are not provided. This differs from the bump stopper 100 according to the embodiment. The other configuration is the same as the configuration of the bump stopper 100 according to the present embodiment, so the same configuration is denoted by the same reference numeral.

  FIG. 4 is a schematic cross-sectional view showing a state of the bump stopper 500 according to the comparative example of the present invention during compression. In FIG. 4, the left side shows the state in which the bump stopper is not compressed, and the right side shows the state in which the amount of compression of the bump stopper has reached a predetermined amount. In each of the drawings, a schematic cross-sectional view (a cross-sectional view of a part of a cross-section cut along a plane including the central axis) is shown.

  FIG. 5 is a graph showing the change of the spring constant with respect to the amount of compression in the bump stopper 100 according to the embodiment of the present invention and the bump stopper 500 according to the comparative example. The graph shown by the solid line L1 is a graph showing the change of the spring constant to the compression amount in the bump stopper 100 according to the present embodiment, and the graph shown by the dotted line L2 is the change of the spring constant to the compression amount in the bump stopper 500 according to the comparative example. FIG.

  In the case of the bump stopper 500 according to the present embodiment, the variation amount Y2 from when the spring constant starts to decrease to when the bump constant starts to decrease is 8.49 N / mm in the case of the bump stopper 500 according to the comparative example. The change amount Y1 from when the spring constant starts to decrease to when the spring constant starts to decrease was 4.24 N / mm. As described above, it is understood that the change of the spring constant can be suppressed by adopting the bump stopper 100 according to the present embodiment. In the case of the bump stopper 500 according to the comparative example, the amount of compression was 13 mm when the spring constant began to decrease and then started to increase. The drawings on the right side of FIGS. 2 and 4 show a state in which the amount of compression of the bump stoppers 100 and 500 is 13 mm.

(Others)
In the above embodiment, the configuration in the case where three valleys are provided on the outer periphery of the bump stopper 100 is shown, but in the present invention, a bump stopper having two valleys and four or more valleys are provided. The present invention is also applicable to the bump stoppers. Even in this case, as described above, from the viewpoint of molding, the diameter (the outer diameter of the valley bottom portion) decreases as the valley portion on the tip end side decreases.

DESCRIPTION OF SYMBOLS 100 bump stopper 111 1st peak part 112 2nd peak part 113 3rd peak part 114 4th peak part 121 1st valley part 122 2nd valley part 123 3rd valley part 131 1st annular recessed part 132 2nd annular recessed part 133 3 annular recess 141 fourth annular recess 142 fifth annular recess 143 sixth annular recess 150 tip 160 end surface 200 piston rod 300 cylinder 400 support member

Claims (3)

The bump stopper is configured such that the outer peripheral surface is formed in a bellows shape, and the plurality of peaks and valleys in the bellows shape are configured such that the diameter decreases toward the tip end side,
Inner peripheral surface side, the plurality of respective annular recess on the inner side of the valley is formed Rutotomoni,
A bump stopper characterized in that the inner diameter of a portion having the largest diameter among the annular recesses is set to be smaller as the annular recess on the tip end side in the annular recesses respectively formed inside the plurality of valleys . 2. The bump stopper according to claim 1, wherein a thickness between a valley on the outer peripheral surface side and an annular recess on the inner peripheral surface side inside the valley is set to 5 mm or more. In a cross section obtained by cutting the bump stopper at a plane including the central axis of the bump stopper, the annular recess formed on the inner side of the plurality of valleys is such that both sides of the recess open from the bottom of the recess toward the inner circumferential surface The bump stopper according to claim 1 or 2 , wherein the opening angle is set to 90 ° or more.

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