JP6340797B2 - Bump stopper - Google Patents

Description

  The present invention relates to a bump stopper, and more particularly, to a bump stopper that can be stably deformed during compression by eliminating a drop in the spring constant with respect to an increase in compression amount.

  The bump stopper is provided on the movable component, and when the movable component is bent to near the limit of the movable range, the bump stopper collides with the counterpart component and is compressed to absorb the impact. For example, in an example applied to an automobile suspension, the bump stopper is mounted on a piston rod of a shock absorber, and when the piston rod contracts near the limit toward the inside of the cylinder, it collides with the end face of the cylinder and is compressed. To absorb the shock.

  Such a bump stopper is generally formed into a cylindrical shape by an elastic material, and is smoothly deformed when compressed by receiving an impact, and in order to stabilize the deformed state, a plurality of peaks and valleys are formed on the outer peripheral surface. (Patent document 1).

  Here, a bump stopper according to this conventional example will be described with reference to FIGS. FIG. 8 is a side view of a bump stopper according to a conventional example. FIG. 9 is a cross-sectional view showing a state when the bump stopper according to the conventional example is compressed. FIG. 10 is a graph showing the relationship between the compression amount and the load in the bump stopper according to the conventional example. FIG. 11 is a graph showing the relationship between the spring constant and the compression amount in the bump stopper according to the conventional example. FIG. 9 shows a state in which the compression amount increases in the order of (a), (b), and (c).

  As shown in FIG. 8, on the outer peripheral surface of the bump stopper 100, a first peak 111, a second peak 112, a third peak 113, and a first peak are sequentially formed from the front end side (the lower side in FIG. 8). A trough 121, a second trough 122, and a third trough 123 are formed. Each peak 111, 112, 113 is formed as an independent annular peak, while each valley 121, 122, 123 is also formed as an independent annular valley.

  The diameters of the peak portions 111 to 113 and the valley portions 121 to 122 are set so as to increase from the front end side to the rear end side in consideration of material fluidity during molding. That is, if the diameter of the first peak 111 is D11, the diameter of the second peak 112 is D12, and the diameter of the third peak 113 is D13, the peak diameter is D11 <D12 <D13, and the first valley When the diameter of 121 is D21, the diameter of the second valley 122 is D22, and the diameter of the third valley 123 is D23, the valley dimension is D21 <D22 <D23. For this reason, the thickness of the site | part of the 1st trough part 121 is the thinnest, and the thickness of the site | part of the 3rd trough part 123 is the thickest. Along with this, when compared with each valley, the rigidity of the site of the first valley 121 is the lowest, the rigidity of the site of the third valley 123 is the highest, and the stiffness is from the front end side to the rear end side. It is changing in stages.

  Therefore, when the bump stopper 100 is compressed by applying a load from the axial direction (vertical direction in FIGS. 8 and 9) to the bump stopper 100 from the unloaded state, first, the portion of the first valley 121 is deformed so as to be compressed ( Next, the second trough portion 122 is deformed so as to be compressed (see FIG. 9B). And finally, it deform | transforms so that the site | part of the 3rd trough part 123 may compress (refer FIG.9 (c)). As described above, the bump stopper 100 according to the conventional example is deformed so that the plurality of valleys are sequentially compressed.

  Here, the relationship between the amount of compression and the load (load necessary for compression) will be described with reference to the graph of FIG.

  In the process of deforming the first trough 121 from the no-load state so as to be compressed, the second trough 122 and the third trough 123 are not deformed yet, but they work so as to stretch, and the bump stopper Since the spring constant in the compression direction of the entire 100 is constant or gradually increases, the load increases substantially linearly as the compression amount increases (L10 in the graph). Next, when the portion of the second valley portion 122 starts to deform, the spring constant decreases, and the rate of increase in load with respect to increase in compression amount decreases (L11 in the graph). After that, while the second trough 122 is deformed, the third trough 123 works to be stretched without deformation, the spring constant increases again, and the rate of increase in load with respect to the increase in compression amount increases. (L12 in the graph). And if the 3rd trough part 123 begins to deform | transform, a spring constant will become low again and the ratio of the increase in load with respect to the increase in compression amount will fall (L13 in a graph).

  As described above, the bump stopper 100 according to the conventional example is deformed so as to be compressed stepwise from the tip side at a plurality of valley portions formed in an annular shape on the outer peripheral surface when a load is applied. As shown in the graph of FIG. 10, the load does not increase smoothly as the amount of compression increases. In such a deformed state, as shown in the graph showing the relationship between the compression amount and the spring constant shown in FIG. 11, portions X1 and X2 in which the spring constant greatly decreases with the increase in the compression amount are generated. Change is not constant.

  From the viewpoint of absorbing the impact, this means that in the process in which the bump stopper 100 is compressed, the change in the compression load on the bump stopper 100 becomes non-uniform and does not change smoothly. For this reason, when this bump stopper 100 is applied to a shock absorber for an automobile suspension, it affects the steering performance and riding comfort of the vehicle. doing.

  In addition, if all the diameters of the troughs are reduced and formed so as to have the same diameter, it is possible to suppress deformation of the plurality of trough parts so as to be compressed in stages, but 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 2013-170670 A

  Accordingly, an object of the present invention is to provide a bump stopper that can be smoothly compressed when a load is applied by eliminating a drop in the spring constant with respect to an increase in the amount of compression.

  Other problems of the present invention will become apparent from the following description.

1. In the bump stopper that has a shaft hole that penetrates between the front end and the rear end, has a trough on the outer peripheral surface, and absorbs shock by being compressed,
The valley is formed in a spiral shape ,
The thickness between the inner peripheral surface of the shaft hole and the trough is formed so as to gradually increase from one end of the trough along the other end,
A bump stopper, characterized by being configured so that the rigidity increases smoothly and continuously from the front end side toward the rear end side .

  2. 2. The bump stopper according to claim 1, wherein a plurality of the valley portions are formed on the outer peripheral surface.

  3. 3. The bump stopper according to claim 1 or 2, wherein an axial hole is provided along the axial direction of the central portion, and a spiral valley is formed on the inner peripheral surface of the axial hole.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the spring constant with respect to the increase in compression amount can be eliminated, and the bump stopper which can be compressed smoothly when a load is added can be provided.

The side view which shows 1st Embodiment of the bump stopper which concerns on this invention Sectional drawing which shows the mode at the time of the compression in the bump stopper which concerns on this invention The graph which shows the relationship between the spring constant and compression amount in the bump stopper which concerns on this invention Explanatory drawing which shows the example which applied the bump stopper based on this invention to the shock absorber of the suspension of a motor vehicle Sectional drawing which shows 2nd Embodiment of the bump stopper which concerns on this invention Schematic diagram showing a state where the bump stopper having two valleys formed on the outer peripheral surface is viewed from the tip side. The figure explaining the mode of a deformation | transformation at the initial stage of compression of the bump stopper in which only one trough was formed Side view of bump stopper according to conventional example Sectional drawing which shows the mode at the time of the compression in the bump stopper which concerns on a prior art example Graph showing the relationship between the compression amount and load in the bump stopper according to the conventional example The graph which shows the relationship between the spring constant and compression amount in the bump stopper which concerns on a prior art example

  Hereinafter, embodiments of the present invention will be described in detail.

(First embodiment)
FIG. 1 is a side view showing a first embodiment of a bump stopper according to the present invention.

  The bump stopper 1A is made of an elastic material such as urethane foam and is formed in a cylindrical shape whose outer diameter (outer diameter of the peak portion 3 described later) gradually decreases toward the lower end 11 in FIG. On the outer peripheral surface, a trough portion 2 (first trough portion) that stabilizes a deformed state when a thin portion is partially formed and compressed is formed.

  Unlike the conventional valleys 121 to 123 formed in an annular shape as shown in FIG. 8, the valley 2 in the present invention is formed in a spiral on the outer peripheral surface of the bump stopper 1A. That is, the trough portion 2 is formed by one spiral groove that turns the outer peripheral surface in the circumferential direction from the front end 11 side to the rear end 12 side of the bump stopper 1A. As a result, the outer peripheral surface of the bump stopper 1 </ b> A has only one spiral trough 2, and the outer peripheral surface is swung in the circumferential direction in the same manner as the trough 2 between the pitches of the troughs 2. Only one spiral peak 3 (first peak) is formed.

  The valley portion 2 has the same width and the same depth over the entire length except for both end portions 21 and 22, and the pitch is also formed to be the same pitch over the entire length. The end portion 21 of the trough portion 2 arranged on the front end 11 side of the bump stopper 1A starts at a predetermined distance from the front end 11 and the end portion 22 of the trough portion 2 arranged on the rear end 12 side of the bump stopper 1A. Is formed so as to reach the rear end 12. Thereby, the crest 3 forms an annular portion 31 at the tip 11 of the bump stopper 1A.

  A central portion of the bump stopper 1A has a shaft hole 4 penetrating through the front end 11 and the rear end 12 along the axial direction (vertical direction in FIG. 1). The shaft hole 4 is a portion through which the cylinder rod is inserted when the bump stopper 1A is attached to, for example, a cylinder rod of a shock absorber.

  In the present embodiment, the shaft hole 4 includes a straight pipe portion 41 extending with the same diameter from the rear end 12 to the front end 11 side of the bump stopper 1A, and an inner peripheral surface of the annular portion 31 following the straight pipe portion 41. And a large-diameter portion 42 having a partially formed large inner diameter. Since the valley portion 2 has the same width and the same depth over the entire length, the thickness between the inner peripheral surface of the straight pipe portion 41 of the shaft hole 4 and the spiral valley portion 2 is the same as that of the valley portion 2. It is formed so as to gradually increase from one end 21 along the other end 22. Accordingly, the rigidity in the valley 2 of the bump stopper 1A is configured to increase smoothly and continuously from the front end 11 side to the rear end 12 side of the bump stopper 1A. The tip 11 side of the bump stopper 1A is partially thin at the large diameter portion 42 of the shaft hole 4.

  Next, with reference to FIG. 2 and FIG. 3, the action when the bump stopper 1A receives and compresses the load in the axial direction will be described. FIG. 2 is a cross-sectional view showing a state of the bump stopper according to the present invention during compression, and shows a half of the cross section cut along a plane passing through the central axis of the bump stopper. FIG. 3 is a graph showing the relationship between the spring constant and the compression amount in the bump stopper according to the present invention. FIG. 2 shows a state in which the compression amount increases in the order of (a), (b), and (c).

  When the bump stopper 1A is compressed by applying a load in the axial direction from an unloaded state, first, the annular portion 31 of the tip 11 of the bump stopper 1A formed in a thin shape is deformed so as to be compressed (see FIG. 2A). ).

  In this process, the part where the valley part 2 is formed is not yet deformed and works so that the rear end 12 side of the annular part 31 is stretched, and the spiral valley part 2 has a constant width W over the entire length. Keep it. For this reason, as the amount of compression increases, the spring constant of the bump stopper 1A is constant or gradually increases (L1 in FIG. 3).

  Next, when a further load is applied, the portion of the bump stopper 1A where the valley 2 is formed begins to deform so as to be compressed (see FIG. 2B). Here, as described above, the bump stopper 1 </ b> A has the rigidity smoothly along the valley portion 2 as it goes from the front end 11 side to the rear end 12 side of the bump stopper 1 </ b> A by the valley portion 2 formed in a spiral shape. Since it is configured to increase continuously, the deformation of the valley 2 is started from the front end 11 side of the bump stopper 1A and gradually proceeds toward the rear end 12 gradually. As a result, the width of the valley 2 gradually decreases from the rear end 12 side to the front end 11 side of the bump stopper 1A (W1 <W2 <W3), and the width continuously changes. And finally, it deform | transforms so that the whole trough part 2 may be compressed (refer FIG.2 (c)).

  At this time, the change from the start of the deformation of the valley 2 to the compression of the entire valley 2 is not stepwise as in the prior art, but is continuous along the spiral valley 2, so that compression As the amount increases, the spring constant of the bump stopper 1A increases smoothly with a substantially constant slope (L2 in FIG. 3). For this reason, the spring constant does not partially drop as the amount of compression increases, and the entire bump stopper 1A can be deformed so as to be compressed smoothly.

  From the viewpoint of absorbing shock, this is because the change in the compressive load applied to the bump stopper 1A does not become non-uniform as in the prior art in the process of compressing the bump stopper 1A, and changes more smoothly. It will be. Therefore, according to the bump stopper 1A, it is possible to eliminate the drop of the spring constant with respect to the increase in the compression amount, and it is possible to perform the compression smoothly when a load is applied.

  Moreover, according to such a bump stopper 1A, since the valley portion 2 has a spiral shape, when the molding material is filled into the molding die, the molding material spirals along the valley portion 2 (or peak portion 3). Therefore, the portion through which the molding material passes is narrowed at the troughs and is not sufficiently filled as in the prior art, so that molding defects are not caused. Further, since the air rises along the valleys 2 when the molding material is filled, the incidence of non-conforming products containing air is also reduced.

  Next, a specific application example of the bump stopper 1A will be described. FIG. 4 is an explanatory view showing an example in which the bump stopper 1A configured as described above is applied to a shock absorber 200 of an automobile suspension, and the bump stopper 1A is shown in cross section in the drawing.

  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 is absorbed by the hydraulic resistance.

  A support member 230 is fixed to the piston rod 210, and a bump stopper 1 </ b> A is attached between the support member 230 and the end surface 221 of the cylinder 220. The bump stopper 1 </ b> A has a cylinder rod 210 inserted through the shaft hole 4. The end surface of the rear end 12 of the bump stopper 1 </ b> A is disposed so as to contact the support member 230, and the end surface of the front end 11 is slightly separated from the end surface 221 of the cylinder 220. Note that the bump stopper 1 </ b> A 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, as the piston rod 210 moves into the cylinder 220, the bump stopper 1A also moves toward the cylinder 220 toward the A direction in the figure. When the shock absorber 200 further shrinks, the tip 11 of the bump stopper 1A collides with the end surface 221 of the cylinder 220. Thereby, since the bump stopper 1A is compressed, the impact can be absorbed.

  At the time of absorbing the impact, as described above, the change in the spring constant of the bump stopper 1A does not drop. As a result, in the process of compressing the bump stopper 1A, the compressive load of the bump stopper 1A changes more smoothly than in the past. Therefore, the change in the steering performance of the vehicle can be increased and stabilized more smoothly than before. And good steering performance can be realized.

  In addition, some shock absorbers have a structure in which a compression load corresponding to the contraction of the cylinder rod 210 is always applied to the bump stopper because the end surface of the bump stopper at the end is always in contact with the end surface 221 of the cylinder 220. It has been. When applying a conventional bump stopper in which a drop in the spring constant occurs with respect to an increase in the compression amount to such a shock absorber, the change in compression load becomes uneven during the process of compressing the bump stopper, Although there was a problem of adversely affecting the riding comfort, by applying this bump stopper 1A, the compressive load of the bump stopper 1A changes more smoothly than before, so that the riding comfort of the vehicle is better than before. To be able to.

(Second Embodiment)
FIG. 5 is a sectional view showing a second embodiment of the bump stopper according to the present invention. Since the site | part of the same code | symbol as FIG. 1 is a site | part of the same structure, those description uses the description in 1st Embodiment, and abbreviate | omits here.

  This bump stopper 1B is different from the first embodiment in that a valley 5 (second valley) is also formed on the inner peripheral surface of the shaft hole 4.

  The valley 5 is formed on the inner peripheral surface of the shaft hole 4 corresponding to the pitch P of the valley 2 formed on the outer peripheral surface of the bump stopper 1B, more specifically, directly on the inner peripheral surface of the shaft hole 4. Similar to the valley 2, the tube 41 is formed in a spiral shape. That is, the trough 5 is formed by a single spiral groove that turns the inner peripheral surface of the shaft hole 4 in the circumferential direction from the front end 11 side to the rear end 12 side of the bump stopper 1B. As a result, only one spiral valley 5 is formed on the inner circumferential surface of the bump stopper 1B, and the inner circumferential surface is swung in the circumferential direction in the same manner as the valley 5 between the pitch of the valleys 5. Thus, only one peak portion 6 (second peak portion) having a spiral shape is formed.

  The valley portion 5 is also formed to have the same width and the same depth over the entire length, except for both ends, similarly to the valley portion 2, and the pitch is also formed to be the same pitch over the entire length. Has been. Here, the spiral turning directions of the valley portion 2 on the outer peripheral surface and the valley portion 5 on the inner peripheral surface are formed to be the same direction. For this reason, in this bump stopper 1B, a partial thin portion is continuously formed between the pitches of the valley portions 2 on the outer peripheral surface between the crest portion 3 on the outer peripheral surface and the inner peripheral surface of the shaft hole 4. ing. This thin portion is formed so that the thickness gradually increases continuously along the valley portion 5 from the front end 11 side to the rear end 12 side of the bump stopper 1B.

  Therefore, also in this bump stopper 1B, the rigidity in the valley portion 2 is the same as that in the first embodiment in that it increases continuously from the front end 11 side to the rear end 12 side of the bump stopper 1B. When a load is applied in the axial direction, as in the first embodiment, the spring constant of the bump stopper 1B increases smoothly with a substantially constant inclination, and the spring constant increases with the amount of compression as in the prior art. In addition to the effect that the entire bump stopper 1B can be deformed so as to be compressed more smoothly, the inner peripheral surface of the shaft hole 4 has a spiral shape. Since the valley portion 5 is formed, the deformation at the time of compression can be made smoother.

  The valley portion 5 is formed at a position corresponding to the pitch P of the valley portion 2 on the outer peripheral surface of the bump stopper 1B on the inner peripheral surface of the shaft hole 4, so as to be the same position as the pitch of the valley portion 2. It may be formed and has the same effect as described above.

(Other embodiments)
In the present invention, the spiral valley formed on the outer peripheral surface of the bump stopper is not limited to one as described above, but depends on the size of the bump stopper and the required load resistance performance. A plurality may be formed. FIG. 6 is a schematic view of a state in which the bump stopper 1 </ b> C having two valley portions 2 and 2 formed on the outer peripheral surface is viewed from the tip 11 side. Since the site | part of the same code | symbol as FIG. 1 is a site | part of the same structure, those description uses the description in 1st Embodiment, and abbreviate | omits here.

  When forming the several trough part 2, each trough part 2 is made into the same pitch, and the position of the axial direction of each edge part 21 and 21 is also made the same. In order to stabilize at the time of compressive deformation, such a plurality of troughs 2 are arranged with end portions 21 arranged on the tip 11 side of the bump stopper 1C at the same height position in the axial direction of the bump stopper 1C. In addition, it is preferable that the shaft holes 4 are arranged so as to be spaced apart at an equal angle. In FIG. 6, the end portions 21 and 21 of the two trough portions 2 and 2 are arranged to face each other with the shaft hole 4 therebetween and are spaced apart by 180 °. Thereby, the two trough parts 2 and 2 are formed in the outer peripheral surface of bump stopper 1C so that the other trough part 2 may be arrange | positioned between the pitches of one trough part 2. FIG.

  By forming a plurality of valleys 2 in this way, the following effects can be obtained. That is, when a load is applied in the axial direction, compression deformation is started from the end 21 of the valley 2, and therefore, in the case of the bump stoppers 1A and 1B having only one valley 2, as shown in FIG. In the initial stage of compression, the tip 11 side tends to be inclined. However, when a plurality of troughs 2 are formed as in the bump stopper 1C, the end portions 21 of the plurality of troughs 2 begin to compress and deform simultaneously at the initial stage of compression, so that the tip 11 side can be prevented from being inclined. The compression deformation state can be further stabilized as compared with the bump stoppers 1A and 1B having only one valley 2 on the outer peripheral surface.

  As described above, even when the plurality of valley portions 2 formed on the outer peripheral surface are formed, the valley portions 5 can be formed also on the inner peripheral surface of the shaft hole 4 as in the second embodiment. The valleys 5 on the inner peripheral surface can be formed in the same number and arrangement as the valleys 2 on the outer peripheral surface. Thereby, in addition to being able to make the deformation | transformation at the time of compression smoother as mentioned above, it can suppress that the front-end | tip 11 side inclines, and can stabilize a compression deformation state more.

  The bump stoppers 1 </ b> A to 1 </ b> C described above are formed so that the outer diameter of the crest 3 gradually decreases as going to the front end 11, but may be formed to have the same diameter from the front end 11 to the rear end 12. In this case, for example, the depth of the valley portion 2 formed on the outer peripheral surface is deepest on the tip end 11 side and gradually becomes shallower toward the rear end 12 side. Can be formed so as to increase smoothly and continuously from the front end 11 side to the rear end 12 side.

1A, 1B, 1C: Bump stopper 11: Front end 12: Rear end 2: Valley portion 21, 22: End portion 3: Peak portion 31: Circular portion 4: Shaft hole 41: Straight pipe portion 42: Large diameter portion 5: Valley Part 6: Yamabe

Claims (3)

In the bump stopper that has a shaft hole that penetrates between the front end and the rear end, has a trough on the outer peripheral surface, and absorbs shock by being compressed,
The valley is formed in a spiral shape ,
The thickness between the inner peripheral surface of the shaft hole and the trough is formed so as to gradually increase from one end of the trough along the other end,
A bump stopper, characterized by being configured so that the rigidity increases smoothly and continuously from the front end side toward the rear end side .   The bump stopper according to claim 1, wherein a plurality of the valley portions are formed on the outer peripheral surface.   The bump stopper according to claim 1, wherein a spiral trough is formed on an inner peripheral surface of the shaft hole.

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