buffer

Abstract

The present invention provides a dust cover capable of accommodating relative rotation between the first and second fixed parts. [Solution] A large-diameter portion 51 is formed at an axial intermediate position P0 between a first fixing portion 31 fixed to the cylinder 2 and a second fixing portion 41 fixed to the outer shell 21 (outer cylinder). The dust cover 30 is configured such that when the first fixing portion 31 and the second fixing portion 41 rotate relative to each other from 0 to 90 degrees, the inner diameter of the large-diameter portion 51 is greater than or equal to the inner diameter of the second fixing portion 41 (the larger of the inner diameter of the first fixing portion 31 or the inner diameter of the second fixing portion 41). As a result, during the process of the first fixing portion 31 and the second fixing portion 41 rotating relative to each other from 0 to 90 degrees, the inner diameter of the large-diameter portion 51 does not become smaller than the inner diameter of the second fixing portion 41, thereby preventing damage due to twisting.

Description

Technical Field

[0001] The present invention relates to a shock absorber.

Background Art

[0002] Patent Document 1 discloses a shock absorber 1 (hereinafter referred to as "conventional shock absorber") including a rod-side fixing portion 32 (second fixing portion) fixed to a rod cover 25 by a band 34, a counter-rod-side fixing portion 33 (first fixing portion) fixed to an outer cylinder 3 by a band 35, and a diameter-expanded portion 36 (large-diameter portion) provided between the fixing portions 32-33.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional shock absorber, both axial ends are attached between a vehicle body and a bogie of a railway vehicle via mounting rings to which pins are attached. Further, in a conventional shock absorber, one end portion (first fixing portion) of a dust cover is fixed to a cylinder by a band, and the other end portion (second fixing portion) of the dust cover is fixed to an outer cylinder (outer shell) by a band. In a conventional shock absorber, when the cylinder and the outer cylinder rotate relative to each other, that is, when the first fixing portion and the second fixing portion of the dust cover rotate relative to each other, the dust cover may be twisted and damaged.

[0005] An object of the present invention is to provide a shock absorber including a dust cover capable of accepting relative rotation between a first fixing portion and a second fixing portion.

Means for Solving the Problems

[0006] The shock absorber of the present invention is a shock absorber for damping vibrations between two members, the shock absorber comprising a cylinder, a piston rod having a rod portion protruding from the cylinder and a head portion protruding radially from the rod portion, and a cylindrical dust cover having one end fixed to the cylinder and the other end fixed to the head portion, wherein the dust cover has a first fixed portion fixed to the cylinder, a second fixed portion fixed to the head portion, and a large-diameter portion whose outer diameter at the axial center position between the first fixed portion and the second fixed portion is larger than that of the first fixed portion or the second fixed portion, the large-diameter portion being formed such that its diameter is larger than that of the first fixed portion or the second fixed portion when the relative rotation between the cylinder and the piston rod is at least from 0 degrees to 90 degrees. The shock absorber of the present invention is a shock absorber for damping vibrations between two members, the shock absorber comprising: a cylinder; a piston rod having a rod portion protruding from the cylinder and a head portion protruding radially from the rod portion; an outer cylinder provided on the head portion and extending toward the cylinder so as to cover the rod portion; and a cylindrical dust cover, one end of which is fixed to the cylinder and the other end of which is fixed to the outer cylinder, wherein the dust cover has a first fixed portion fixed to the cylinder, a second fixed portion fixed to the outer cylinder, and a large-diameter portion whose outer diameter at the axial center position between the first fixed portion and the second fixed portion is larger than that of the first fixed portion or the second fixed portion, the large-diameter portion being formed such that its diameter is larger than that of the first fixed portion or the second fixed portion when the relative rotation between the cylinder and the piston rod is at least from 0 degrees to 90 degrees. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a shock absorber equipped with a dust cover capable of accepting relative rotation between the first fixed part and the second fixed part. [Brief explanation of the drawing]

[0008] [Figure 1]This is a front view of a buffer according to the first embodiment, showing the outer shell and dust cover in cross-section. [Figure 2] This is an explanatory diagram of the first embodiment, and is a schematic front view showing the dust cover. [Figure 3] This is an explanatory diagram of the first embodiment, and is a schematic cross-sectional view showing the fixing portion of the dust cover. [Figure 4] This figure shows a modified example of the first embodiment, in which the axial intermediate position P0 of the dust cover is located closer to the head portion than the open end position P1 of the outer shell. [Figure 5] This figure shows a modified example of the first embodiment, in which the axial intermediate position P0 of the dust cover is located on the opposite side from the head portion side from the open end position P1 of the outer shell. [Figure 6] This is an explanatory diagram of a second embodiment, showing the outer shell and dust cover in cross-section. [Figure 7] This is an explanatory diagram of a second embodiment, showing a state in which the axial intermediate portion of the dust cover is engaged between the head portion 13 of the piston rod 11 and the cylinder 2 in a conventional shock absorber. [Figure 8] This figure shows modified examples of the first and second embodiments, and is a schematic front view showing the dust cover. [Modes for carrying out the invention]

[0009] (First Embodiment) A first embodiment of the present invention will be described with reference to the attached figures. The following describes the buffer 1, which is to be attached between the body and bogie of a railway vehicle (not shown) via mounting rings 5 ​​and 6 to which pins 3 and 4 are attached. Note that the buffer body of the buffer 1 shown in Figure 1 is the same as a conventional buffer, except for the dust cover 30. Therefore, the buffer body will be described in general terms.

[0010] As shown in Figure 1, the shock absorber 1 comprises a cylinder 2, a piston rod 11, an outer shell 21 (outer cylinder), and a dust cover 30. The piston rod 11 has a rod portion 12 that protrudes from the cylinder 2, and a disc-shaped head portion 13 provided at one end of the rod portion 12 (the "upper side" in Figure 1) that protrudes radially outward from the piston rod 11. The outer shell 21 has one end portion 22 (the "upper side" in Figure 1) fixed to the outer circumference of the head portion 13 of the piston rod 11. In other words, the outer shell 21 is joined to the head portion 13 with the head portion 13 of the piston rod 11 inserted inside the end portion 22.

[0011] The dust cover 30 is formed into a cylindrical shape by sewing together a pair of opposite sides of a rectangular fabric material that has been treated to be dustproof and waterproof. As shown in Figure 1 or Figure 2, the dust cover 30 has a cylindrical first fixing part 31 formed at one end in the axial direction (the "up and down direction" in Figures 1 and 2) (the "lower side" in Figures 1 and 2) and fixed (bound) to the outer circumference of the cylinder 2 by a band 32, and a cylindrical second fixing part 41 formed at the other end in the axial direction (the "upper side" in Figures 1 and 2) and fixed (bound) to the outer circumference of the outer shell 21 by a band 42.

[0012] As shown in Figure 2 or Figure 3, the first fixing portion 31 has a plurality of (eight in the first embodiment) folded portions 33 formed by folding the fabric material in the circumferential direction (clockwise or counterclockwise direction in Figure 3). The width, spacing, and folding direction of the plurality of folded portions 33 do not have to be constant, as long as the first fixing portion 31 is reduced in diameter so that the inner diameter of the first fixing portion 31 becomes the outer diameter of the cylinder 2. Also, it is sufficient that at least one folded portion 33 is formed on the first fixing portion 31.

[0013] The second fixing part 41 has a plurality of overlapping parts 43 formed by folding the fabric material in the circumferential direction. The plurality of overlapping parts 43 do not have to have a constant width, interval, and folding direction as long as the second fixing part 41 is reduced in diameter so that the inner diameter of the second fixing part 41 becomes the outer diameter of the outer shell 21 (outer cylinder). Note that at least one overlapping part 43 may be formed in the second fixing part 41.

[0014] The dust cover 30 has a large-diameter part 51 formed such that the inner diameter at the axial intermediate position P0 between the first fixing part 31 and the second fixing part 41 is larger than the inner diameter of the second fixing part 41 (the larger of the inner diameter of the first fixing part 31 or the inner diameter of the second fixing part 41). The large-diameter part 51 is formed by bulging the axial intermediate position P0 of the dust cover 30 in the radial direction. The large-diameter part 51 is formed to have a larger diameter than both ends of the dust cover 30 by folding and reducing the diameter of both axial ends of the dust cover 30. In other words, the large-diameter part 51 forms the overlapping part 33 and the overlapping part 43 in the first fixing part 31 and the second fixing part 41, and is formed to have a larger diameter than the first fixing part 31 and the second fixing part 41 by reducing the diameter of the first fixing part 31 and the second fixing part 41.

[0015] Next, a method for determining the inner diameter of the axial intermediate position P0 of the large-diameter part 51 of the dust cover 30 (hereinafter referred to as the "inner diameter of the large-diameter part 51") will be described. Here, a method for determining the inner diameter of the large-diameter part 51 that can accept the relative rotation of the first fixing part 31 fixed to the cylinder 2 and the second fixing part 41 fixed to the outer shell 21 (outer cylinder) from 0 degrees to 90 degrees will be described.

[0016] Here, in order to allow the relative rotation of the first fixing part 31 and the second fixing part 41 of the dust cover 30 from 0 degrees to 90 degrees, the inner diameter of the large-diameter part 51 when the relative rotation of the first fixing part 31 and the second fixing part 41 is 90 degrees is equal to the inner diameter of the second fixing part 41 (the larger of the inner diameter of the first fixing part 31 or the inner diameter of the second fixing part 41), or larger than the inner diameter of the second fixing part 41.

[0017] For the sake of cost, when the inner diameter of the second fixing portion 41 is set to "1", the inner diameter of the large-diameter portion 51 when the relative rotation between the first fixing portion 31 and the second fixing portion 41 of the dust cover 30 is 360 degrees is set to "0". Here, assuming that the inner diameter of the large-diameter portion 51 decreases at a constant rate from 1 to 0 in the process of relatively rotating the first fixing portion 31 and the second fixing portion 41 from 0 degrees to 360 degrees, when the relative rotation between the first fixing portion 31 and the second fixing portion 41 is 90 degrees, the inner diameter of the large-diameter portion 51 is "1-(90 / 360)", that is, "3 / 4". Incidentally, when the relative rotation between the first fixing portion 31 and the second fixing portion 41 is 180 degrees, the inner diameter of the large-diameter portion 51 is "1 / 2", and when the relative rotation between the first fixing portion 31 and the second fixing portion 41 is 270 degrees, the inner diameter of the large-diameter portion 51 is "1 / 4".

[0018] Therefore, if the inner diameter of the large-diameter portion 51 when the relative rotation between the first fixing portion 31 and the second fixing portion 41 is 0 degrees is 1.33 (rounded down to the third decimal place of 4 / 3) or more, the inner diameter of the large-diameter portion 51 when the relative rotation between the first fixing portion 31 and the second fixing portion 41 is 90 degrees can be made 1 or more, that is, it can be maintained at or above the inner diameter of the second fixing portion 41. For example, when the outer diameter of the outer shell 21 (the inner diameter of the second fixing portion 41) is 100 mm, by setting the inner diameter of the large-diameter portion 51 of the dust cover 30 to 133 mm (100 mm × 1.33) or more, the dust cover 30 that can accept the relative rotation between the first fixing portion 31 and the second fixing portion 41 from 0 degrees to 90 degrees can be obtained.

[0019] Here, in a conventional shock absorber, with the relative rotation between the cylinder and the outer shell (outer cylinder), the first fixing portion and the second fixing portion of the dust cover rotate relative to each other, and there is a risk that the dust cover will twist and break. <00,00099> In contrast, in the first embodiment, a large-diameter portion 51 is formed at the axial intermediate position P0 between the first fixing portion 31 fixed to the cylinder 2 and the second fixing portion 41 fixed to the outer shell 21 (outer cylinder), and when the first fixing portion 31 and the second fixing portion 41 rotate relative to each other from 0 degrees to 9 degrees, the dust cover 30 is configured such that the inner diameter of the large-diameter portion 51 is at or above the inner diameter of the second fixing portion 41 (the larger of the inner diameters of the first fixing portion 31 and the second fixing portion 41). The large-diameter portion 51 can be formed between the axial ends of the dust cover 30 by forming overlapping portions 33 and 43 on the first fixing portion 31 and the second fixing portion 41, and by reducing the diameter of the first fixing portion 31 and the second fixing portion 41. According to the first embodiment, in the process of the dust cover 30 rotating relative to the first fixing part 31 and the second fixing part 41 from 0 degrees to 90 degrees, the inner diameter of the large diameter part 51 does not become smaller than the inner diameter of the second fixing part 41, thereby preventing damage due to twisting.

[0021] In the first embodiment, as shown in Figure 1, the buffer 1 was configured such that the axial intermediate position P0 of the dust cover 30 is located at the open end position P1 of the outer shell 21 (outer cylinder). However, as shown in Figure 4, the buffer 1 may also be configured such that the axial intermediate position P0 of the dust cover 30 is located on the head portion 13 side (the "upper side" in Figure 4) of the open end position P1 of the outer shell 21 (outer cylinder). In this case, if the axial intermediate position P0 of the dust cover 30 is located at the open end position P1 of the outer shell 21, this can be addressed by setting a larger inner diameter for the large-diameter portion 51 of the dust cover 30. Furthermore, as shown in Figure 5, the buffer 1 may be configured such that the axial intermediate position P0 of the dust cover 30 is located on the opposite side from the head portion 13 (the "lower side" in Figure 5) from the open end position P1 of the outer shell 21 (outer cylinder). In this case, the inner diameter of the large-diameter portion 51 of the dust cover 30 can be set smaller compared to the case where the axial intermediate position P0 of the dust cover 30 is located at the open end position P1 of the outer shell 21.

[0022] (Second Embodiment) Next, a second embodiment will be described with reference to Figure 6 or Figure 7. Note that the same designations and reference numerals will be used for parts common to both the first embodiment and the second embodiment, and redundant explanations will be omitted. In the first embodiment, the second fixing portion 41 of the dust cover 30 was fixed to the outer shell 21 (outer cylinder) to constitute the buffer 1.

[0023] In contrast, in the second embodiment, the shock absorber 1 does not have an outer shell 21 (outer cylinder). In the second embodiment, as shown in Figure 6, the second fixing portion 41 of the dust cover 30 is fixed to the outer circumference of the head portion 13 of the piston rod 11 (the portion where the outer shell 21 was fixed in the first embodiment), and the dust cover 30 is configured such that when the first fixing portion 31 and the second fixing portion 41 rotate relative to each other from 0 to 90 degrees, the inner diameter of the large diameter portion 51 is greater than or equal to the inner diameter of the second fixing portion 41 (the larger of the inner diameter of the first fixing portion 31 or the inner diameter of the second fixing portion 41).

[0024] In the second embodiment, the same effects and advantages as those of the first embodiment described above can be achieved. Furthermore, as shown in Figure 7, in conventional shock absorbers that do not have an outer shell 21 (see Figure 1), if the piston rod 11 is retracted while the dust cover 30 is twisted, the axial intermediate portion 35 of the dust cover 30 will be reduced in diameter (moving inward in the radial direction), which could cause the dust cover 30 to get caught between the head portion 13 of the piston rod 11 and the cylinder 2, preventing the shock absorber from being retracted to its minimum length. However, in the second embodiment, the axial intermediate position P0 is bulged radially outward to form a large-diameter portion 51 between the first fixing portion 31 and the second fixing portion 41. As a result, the axial intermediate portion 35 of the dust cover 30 does not move inward in the radial direction, and the situation in which the dust cover 30 gets caught between the head portion 13 of the piston rod 11 and the cylinder 2 can be avoided.

[0025] The embodiments are not limited to the forms described above, and can be configured as follows, for example. In the embodiment described above, by folding and reducing the diameter of both axial ends of the dust cover 30, a large-diameter portion 51 with a larger diameter than both ends of the dust cover 30 is formed between the first fixing portion 31 and the second fixing portion 41. Alternatively, as shown in Figure 8, the dust cover 30 may be constructed by folding the fabric material of the large-diameter portion 51 between the first fixing portion 31 and the second fixing portion 41 in the circumferential direction to form a plurality of folded portions 37. In this case, when the first fixing part 31 and the second fixing part 41 rotate relative to each other from 0 to 90 degrees, the wrinkles created by the circumferential shift of the multiple folded parts 37 can absorb the axial tension acting on the first fixing part 31 and the second fixing part 41, thereby preventing damage to the dust cover 30. Furthermore, the width, spacing, and folding direction (clockwise or counterclockwise around the axis of the buffer 1) of the multiple folded sections 37 do not necessarily have to be constant. [Explanation of Symbols]

[0026] 1 Shock absorber, 2 Cylinder, 11 Piston rod, 12 Rod section, 13 Head section, 30 Dust cover, 31 First fixing section, 41 Second fixing section, 51 Large diameter section

Claims

1. A damper that reduces vibrations between two members, The aforementioned buffer is, Cylinder and A piston rod having a rod portion protruding from the cylinder and a head portion protruding radially from the rod portion, A cylindrical dust cover, one end of which is fixed to the cylinder and the other end of which is fixed to the head portion, Equipped with, The dust cover comprises a first fixing portion fixed to the cylinder, a second fixing portion fixed to the head portion, and a large-diameter portion whose outer diameter at the axial center position between the first and second fixing portions is larger than that of the first or second fixing portion. The large-diameter portion is a shock absorber formed such that its diameter is larger than the first fixed portion or the second fixed portion when the relative rotation between the cylinder and the piston rod is at least 0 to 90 degrees.

2. A buffer according to claim 1, The first and second fixing portions are shock absorbers whose diameter is reduced by folding the axial ends of the dust cover together, resulting in a smaller diameter than the larger diameter portion.

3. A buffer according to claim 1, The dust cover is a buffer formed such that the first fixing portion and the second fixing portion overlap in the circumferential direction.

4. A damper that reduces vibrations between two members, The aforementioned buffer is, Cylinder and A piston rod having a rod portion protruding from the cylinder and a head portion protruding radially from the rod portion, An outer cylinder provided on the head portion and extending toward the cylinder side so as to cover the rod portion, A cylindrical dust cover, one end of which is fixed to the cylinder and the other end of which is fixed to the outer cylinder, Equipped with, The dust cover comprises a first fixing portion fixed to the cylinder, a second fixing portion fixed to the outer cylinder, and a large-diameter portion whose outer diameter at the axial center position between the first and second fixing portions is larger than that of the first or second fixing portion. The large-diameter portion is a shock absorber formed such that its diameter is larger than the first fixed portion or the second fixed portion when the relative rotation between the cylinder and the piston rod is at least 0 to 90 degrees.

5. A buffer according to claim 4, The first and second fixing portions are shock absorbers whose diameter is reduced by folding the axial ends of the dust cover together, resulting in a smaller diameter than the larger diameter portion.

6. A buffer according to claim 4, The dust cover is a buffer formed such that the first fixing portion and the second fixing portion overlap in the circumferential direction.

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