Dust cover and shock absorber

Abstract

Provided are a dust cover suppressing the shifting of a band, and a shock absorber provided with the dust cover. A second end part, to which the other end side in the axial direction of a cylindrical part is connected, and a third end part, to which one end side in the axial direction of the cylindrical part is connected, are formed on one end-side fixing part of the dust cover. The band is wound between the second end part and the third end part protruding radially outward, so that the band can be prevented from shifting in the axial direction and the one end-side fixing part of the dust cover can be prevented from coming off from a band fastening part of a flange part.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a shock absorber 1 in which a rod-side fixing portion 32 of a dust cover 41 is fixed to an outer periphery 26 of a rod cover 25 by a band 34.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in the above-described shock absorber, when the rod cover is omitted, it is necessary to cover the piston rod with the dust cover. In this case, the rod-side fixing portion (one-end-side fixing portion) of the dust cover is fixed to a flange portion fixed to the distal end portion (one-end-side end portion) of the piston rod using a band. However, since the width (axial length) of the radially outer band fastening portion of the flange portion for fastening the band is narrow, there is a risk that the band will shift in the axial direction.

[0005] An object of the present invention is to provide a dust cover that suppresses band displacement, and a shock absorber including the dust cover.

Means for Solving the Problems

[0006] The dust cover of the present invention is characterized by comprising: a bellows section having peaks and valleys; a first wall section connected to a first end formed at one axial end of the bellows section and extending radially inward; a cylindrical section connected to a second end formed at the radially outer end of the first wall section and having a recess formed in which at least a portion in the axial direction is recessed radially inward; a second wall section connected to a third end formed at one axial end of the cylindrical section and extending radially inward; and an inclined section connected to a fourth end formed at the radially inner end of the second wall section and extending inclined radially inward. The buffer of the present invention is characterized in that the dust cover has a bellows section having peaks and valleys, a first wall section connected to a first end formed at one axial end of the bellows section and extending radially from the inside to the outside, and contacting a first contact surface at the other axial end of the flange section, a cylindrical section connected to a second end formed at the radially outer end of the first wall section and having a recess formed in which at least a portion in the axial direction is recessed radially inward in its natural state, and contacting the radially outer side of the flange section, a third end formed at one axial end of the cylindrical section and extending radially from the outside to the inside, and contacting a second contact surface at one axial end of the flange section, and a fourth end formed at the radially inner end of the second wall section and being formed to extend inclined from the inside to the outside, and the band is provided on the radially outer side of the cylindrical section.

[0007] According to one embodiment of the present invention, a dust cover that prevents band displacement and a buffer equipped with the dust cover can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of the buffer according to the axial plane of this embodiment. [Figure 2]This is an explanatory diagram of this embodiment, showing an enlarged cross-sectional view in the axial plane, illustrating the fixing portion at one end of the dust cover and the radially outer end of the flange portion in their natural state before band fastening. [Figure 3] This is an enlarged view of section A in Figure 1. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described with reference to the attached diagram. Here, we illustrate a twin-tube, horizontally mounted uniflow hydraulic shock absorber 1 (hereinafter referred to as "shock absorber 1") installed as a yaw damper between the car bodies of a railway vehicle. For convenience, the left side in Figure 1 is referred to as the axial end, the right side in Figure 1 as the axial end, the upper side in Figure 2 as the radially outer side, and the lower side in Figure 2 as the radially inner side.

[0010] As shown in Figure 1, the shock absorber 1 has a cylinder 2 in which an inner cylinder 3 and an outer cylinder 4 are arranged coaxially. The shock absorber 1 has an annular reservoir 5 formed between the inner cylinder 3 and the outer cylinder 4 of the cylinder 2. The shock absorber 1 has a closing member 6 that closes the axial end of the inner cylinder 3 and the outer cylinder 4. The closing member 6 functions as a rod guide that guides the piston rod 10. The shock absorber 1 has a closing member 7 that closes the axial end of the inner cylinder 3 and the outer cylinder 4. The closing member 7 has a closing portion 8 that closes the axial end of the inner cylinder 3 and a closing portion 9 that closes the axial end of the outer cylinder 4.

[0011] A piston 13 is inserted inside the inner cylinder 3, dividing the interior of the inner cylinder 3 into a first chamber 11 at one axial end and a second chamber 12 at the other axial end. The other axial end of the piston rod 10 is fixed to the piston 13. The axial end of the piston rod 10 is inserted through the closure member 6 and extends to the outside of the cylinder 2. The buffer 1 is provided in the closure member 7 and has a passage 18 that connects the second chamber 12 and the reservoir 5. The passage 18 is provided with a check valve 19 that allows the flow of working fluid only from the reservoir 5 to the second chamber 12.

[0012] The buffer 1 is provided on the piston 13 and has a check valve 14 that allows the flow of working fluid only from the second chamber 12 to the first chamber 11. The buffer 1 is provided on the blocking member 6 and has a passage 15 that connects the first chamber 11 and the reservoir 5. The buffer 1 is provided in the passage 15 and has a valve mechanism 16 that adjusts the flow of working fluid from the first chamber 11 to the reservoir 5. Working fluid is sealed in the first chamber 11 and the second chamber 12 as the working fluid. In addition, working fluid and gas are sealed in the reservoir 5 as the working fluid.

[0013] The buffer 1 has a mounting eye 21 that is fixed to the closing section 9 and connected to one side of the railway vehicle. A pin 23 is attached to the mounting eye 21 via a bush 22. On the other hand, the buffer 1 has a flange portion 31 that is fixed to the tip (one end) of the piston rod 10. The buffer 1 has a mounting eye 25 that is fixed to the flange portion 31 and the piston rod 10 and connected to the other side of the railway vehicle. A pin 27 is attached to the mounting eye 25 via a bush 26.

[0014] The shock absorber 1 has a dust cover 41 that covers the piston rod 10 protruding from the closing member 6. The dust cover 41 has a bellows section 42 in which peaks 43 and valleys 44 alternately continue in the axial direction, a one-end fixing section 51 connected to one end of the bellows section 42, and a other-end fixing section 45 connected to the other axial end of the bellows section 42. The one-end fixing section 51 is fixed by a band 52 to a band fastening section 33 (outer cylindrical surface) formed on the radially outer end 32 (thin-walled section) of the flange section 31. On the other hand, the other-end fixing section 45 is fixed by a band 46 to the outer peripheral surface 17 of one end of the outer cylinder 4. The dust cover 41 is a resin molded product.

[0015] As shown in Figure 2, the one-end fixing portion 51 has a first end portion 53 formed at the axial end (valley portion 44) of the bellows portion 42. The one-end fixing portion 51 has a first wall portion 54 connected to the first end portion 53 and formed to extend radially outward from the first end portion 53 (radially inward). The first wall portion 54 contacts the first contact surface 34 of the flange portion 31 when the one-end fixing portion 51 is fastened to the flange portion 31 by the band 52 (hereinafter referred to as the "mounted state") (see Figure 3). The first contact surface 34 is formed on the end face on the other axial end side of the radially outward end portion 32 of the flange portion 31.

[0016] The one-end fixing portion 51 has a second end portion 55 formed at the radially outer end of the first wall portion 54. The first wall portion 54 is inclined such that when the dust cover 41 is in its natural state (a state in which no external force is acting, hereinafter referred to as "natural state"), the first end portion 53 is located axially to the other end (the "right side" in Figure 2) than the second end portion 55. The radial length of the first wall portion 54 is shorter than the radial length of the bellows portion 42 from the peak portion 43 to the valley portion 44.

[0017] The one-end fixing portion 51 is connected to the second end portion 55 and has a cylindrical portion 56 formed to extend from the second end portion 55 (the other axial end) toward the one-end side in the axial direction. In its natural state (see Figure 2), the cylindrical portion 56 has a recess 57 in which the axial center is recessed radially inward. On the other hand, when the cylindrical portion 56 is in the mounted state, it abuts against the band fastening portion 33 of the flange portion 31. In Figure 2, the cylindrical portion 56 is formed to be concave along its entire length, but the recess 57 can be formed by recessing only the axial center radially inward.

[0018] The one-end-side fixing portion 51 has a third end portion 58 formed at an end on one end side of the tubular portion 57. The third end portion 58 and the second end portion 55 are formed to protrude radially outward relative to the tubular portion 56. In other words, the second end portion 55 and the third end portion 58 have an outer diameter larger than that of the tubular portion 56. The one-end-side fixing portion 51 has a second wall portion 59 connected to the third end portion 58 and formed to extend radially inward from the third end portion 58 (radially outer side). In other words, the one-end-side fixing portion 51 has a first wall portion 54 extending radially inward from the end (the second end portion 55) on the other end side of the tubular portion 56, and a second wall portion 59 extending radially inward from the end (the third end portion 58) on one end side of the tubular portion 56.

[0019] The second wall portion 59 abuts against the second abutment surface 35 of the flange portion 31 in the mounted state (see FIG. 3). The second abutment portion 35 is formed on the end surface on one axial end side of the radially outer end 32 of the flange portion 31. The second abutment portion 35 is disposed on a plane perpendicular to the axis of the dust cover 41 (hereinafter referred to as "axis-perpendicular plane"). Here, the first abutment surface 34 is disposed on the axis-perpendicular plane. The flange portion 31 has a thick portion 38 in which the end surface 36 on one axial end side is inclined relative to the axis-perpendicular plane such that the wall thickness (axial length) decreases from the radially inner side toward the radially outer side. Thereby, an annular step portion 37 is formed between the second abutment surface 35 of the flange portion 31 and the end surface 36 on one axial end side.

[0020] The one-end-side fixing portion 51 has a fourth end portion 60 formed at the radially inner end of the second wall portion 59. In the natural state, the second wall portion 59 is inclined such that the fourth end portion 60 is positioned on one axial end side (the "left side" in FIG. 2) relative to the third end portion 58. In the natural state, the axial distance between the first end portion 53 and the fourth end portion 60 of the one-end-side fixing portion 51 is longer than the axial distance between the second end portion 55 and the third end portion 58. In other words, the one-end-side fixing portion 51 is formed such that the first wall portion 54 and the second wall portion 59 open toward the radially inner side in the natural state.

[0021] The one-end-side fixing portion 51 is connected to the fourth end portion 60, and has an inclined portion 61 formed to extend radially outward from the fourth end portion 60. The inclined portion 61 is inclined so as to move away from the second wall portion 59 from the radially inner side toward the radially outer side. The one-end-side fixing portion 51 has a notch portion 62 (slit) extending at a constant width radially inward from the radially outer end of the inclined portion 61 (the open end of the one-end-side fixing portion 51). Thereby, when the dust cover 41 is attached, the one-end-side fixing portion 51 can expand the diameter of the open end by opening the notch portion 62. A plurality of the notch portions 62 can be formed in the one-end-side fixing portion 51.

[0022] Next, the procedure for attaching the dust cover 41 to the shock absorber 1 main body will be described. First, the shock absorber 1 main body is inserted from the other end side where the mounting eye 21 is provided into the opening of the one-end-side fixing portion 51 of the dust cover 41. At this time, by opening the notch portion 62 to expand the diameter of the open end of the one-end-side fixing portion 51, the pin 23 mounted on the mounting eye 21 can be easily inserted into the dust cover 41.

[0023] Next, the shock absorber 1 main body is caused to protrude from the other-end-side fixing portion 45 of the dust cover 41. Thereby, the other-end-side fixing portion 45 of the dust cover 41 is fitted to the outer peripheral surface 17 of the outer cylinder 4. Next, the other-end-side fixing portion 45 of the dust cover 41 is axially positioned relative to the outer cylinder 4, and the band 46 wound around the outer periphery of the other-end-side fixing portion 45 of the dust cover 41 is tightened. Thereby, the other-end-side fixing portion 45 is pressurized radially inward and fastened to the end portion on one axial end side of the outer cylinder 4. The timing for tightening the band 46 may be appropriately selected, and for example, may be the time when the band 52 on the one axial end side is tightened.

[0024] Next, as shown in FIG. 2, the flange portion 31 of the shock absorber 1 main body is inserted into the opening of the one-end-side fixing portion 51 of the dust cover 41. In the present embodiment, the flange portion 31 can be easily inserted into the one-end-side fixing portion 51 by opening the notch portion 62 to expand the diameter of the open end of the one-end-side fixing portion 51.

[0025] Next, the fixing portion 51 at one end of the dust cover 41 is positioned axially (left-right direction in Figure 2) relative to the flange portion 31. In this embodiment, as shown in Figure 2, the cylindrical portion 56 of the fixing portion 51 and the band fastening portion 33 of the flange portion 31 are positioned opposite each other with their axial centers aligned. Also, in this embodiment, the radially outer end portion 32 of the flange portion 31 fits between the first wall portion 54 and the second wall portion 59 of the fixing portion 51, so the fixing portion 51 at one end can be easily positioned axially relative to the flange portion 31.

[0026] Next, the band 52 is wrapped around the outer circumference of the fixing portion 51 at one end of the dust cover 41. In this embodiment, the band 52 is wrapped between the second end 55 and the third end 58 that protrude radially outward from the cylindrical portion 56 of the fixing portion 51 at one end, so that the band 52 can be easily positioned axially with respect to the fixing portion 51 at one end of the dust cover 41 and the band fastening portion 33 of the buffer 1 body. Next, the band 52 wrapped around the outer circumference of the fixing portion 51 at one end of the dust cover 41 is tightened. As a result, the cylindrical portion 56 of the fixing portion 51 at one end is pressed radially inward and fastened to the band fastening portion 33 of the flange portion 31.

[0027] As a result, as shown in Figure 3, the cylindrical portion 56 of the one-end fixing portion 51 is in close contact with the band fastening portion 33 (outer cylindrical surface) of the flange portion 31 at both axial ends, eliminating the recess 57 and making it flat along its entire axial length. Consequently, the first wall portion 54 of the one-end fixing portion 51 is pressed against the first contact surface 34 of the flange portion 31, and is inclined with respect to the plane perpendicular to the axis such that the second end portion 55 is located axially further towards the other end than the first end portion 53, or in other words, the first end portion 53 is positioned further towards the first contact surface 34 than the second end portion 55.

[0028] On the other hand, the second wall portion 59 of the one-end fixing portion 51 is pressed against the second contact surface 35 of the flange portion 31 and is inclined with respect to the plane perpendicular to the axis such that the third end portion 58 is located axially toward one end than the fourth end portion 60, in other words, the fourth end portion 60 is recessed toward the second contact surface 35 than the third end portion 58. In this way, the radially outer end portion 32 of the flange portion 31 is axially clamped by the pair of wall portions 54 and 59 due to the spring force generated by the material of the dust cover 41. Furthermore, in this embodiment, since the second wall portion 59 is inclined to recess toward the other end in the axial direction, the fourth end portion 60 of the one-end fixing portion 51 can be tightly fitted into the stepped portion 37 of the flange portion 31.

[0029] In conventional dust covers, the width of the band fastening portion on the flange is limited (short axial length), making it difficult to position the fixing portion on one end axially relative to the flange. Furthermore, conventional dust covers lack a structure to prevent the band from shifting, so there is a risk that the band may shift axially relative to the fixing portion on one end and detach from the flange.

[0030] In contrast, in this embodiment, the one-end fixing portion 51 is provided on the other axial end side of the cylindrical portion 56 and has a first wall portion 54 extending radially inward from the second end portion 55, and a second wall portion 59 provided on the one axial end side of the cylindrical portion 56 and extending radially inward from the third end portion 58. When the dust cover 41 is attached, the radially outer end portion 32 of the flange portion 31 fits between the first wall portion 54 and the second wall portion 59, so that the one-end fixing portion 51 of the dust cover 41 can be easily positioned axially with respect to the flange portion 31.

[0031] In this embodiment, a recess 57 is formed in the cylindrical portion 56 of the one-end fixing portion 51, which is recessed in the axial center when in its natural state. This makes it possible to increase the axial distance between the first wall portion 54 and the second wall portion 59 radially inward, and to easily accommodate the radially outer end 32 of the flange portion 31 between the first wall portion 54 and the second wall portion 59.

[0032] In this embodiment, when installed, the cylindrical portion 56 is in close contact with the band fastening portion 33 of the flange portion 31, and the cylindrical portion 56 becomes flat along its entire axial length. As a result, the first wall portion 54 is pressed against the first contact surface 34 of the flange portion 31, and the radially inward first end portion 53 is inclined to extend further toward the first contact surface 34 than the radially outward second end portion 55. On the other hand, the second wall portion 59 is pressed against the second contact surface 35 of the flange portion 31, and the fourth end portion 60 is inclined to extend further toward the second contact surface 35 than the third end portion 58.

[0033] In other words, the spring force generated by the material of the dust cover 41 allows the pair of wall portions 54 and 59 to axially clamp the radially outer end 32 of the flange portion 31, thereby improving the sealing performance of the dust cover 41. Furthermore, in this embodiment, the fourth end portion 60 is made to fit tightly into the stepped portion 37 formed on the flange portion 31, which further improves the sealing performance of the dust cover 41.

[0034] In this embodiment, a notch 62 is formed in the inclined portion 61 of the dust cover 41, which is the insertion opening of the shock absorber 1 body, extending radially inward from the open end (the radially outer end). By opening the notch 62 and expanding the diameter of the inclined portion 61 (the one-end side of the one-end fixing portion 51), the flange portion 31 can be easily inserted into the one-end fixing portion 51 of the dust cover 41, thereby improving ease of assembly.

[0035] In this embodiment, a second end 55 is formed on the fixing portion 51 at one end of the dust cover 41, to which the other axial end of the cylindrical portion 56 is connected and which protrudes radially outward, and a third end 58 is formed on which the one axial end of the cylindrical portion 56 is connected and which protrudes radially outward. A band 52 is wrapped around the second end 55 and the third end 58, so that the band 52 does not shift in the axial direction, and the fixing portion 51 at one end of the dust cover 41 does not come off the band fastening portion 33 of the flange portion 31.

[0036] The embodiments are not limited to the forms described above, and can be configured as follows, for example. In this embodiment, the second contact surface 35 of the flange portion 31, against which the second wall portion 59 of the dust cover 41 abuts, is arranged parallel to the plane perpendicular to the axis of the dust cover 41. In contrast, the second contact surface 35 can be formed to be inclined with respect to the plane perpendicular to the axis so as to extend from the radially outer side to the radially inner side toward the other end in the axial direction (towards the first contact surface 34). In this case, the fourth end portion 60 of the fixing portion 51 on one end can be tightly fitted into the stepped portion 37 formed on the flange portion 31, thereby further improving the sealing performance of the dust cover 41.

[0037] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0038] This application claims priority under Japanese Patent Application No. 2023-117626, filed on 19 July 2023. The entire disclosure of Japanese Patent Application No. 2023-117626, filed on 19 July 2023, including the specification, claims, drawings, and abstract, is incorporated into this application by reference. [Explanation of symbols]

[0039] 1 buffer, 41 dust cover, 42 bellows section, 43 peak section, 44 valley section, 53 first end, 54 first wall section, 55 second end, 56 cylindrical section, 57 recess, 58 third end, 59 second wall section, 60 fourth end, 61 inclined section

Claims

1. A dust cover used in a shock absorber, A bellows section having a mountain section and a valley section, A first wall portion is connected to a first end formed at one axial end of the bellows section and is formed to extend from the radially inward to the radially outward, A cylindrical portion is connected to a second end formed at the radially outer end of the first wall portion, and has a recess formed in which at least a portion in the axial direction is recessed radially inward, A second wall portion is formed to be connected to a third end formed at one end of the axial direction of the cylindrical portion, and extends from the radially outer side to the radially inner side, A fourth end is formed at the radially inner end of the second wall portion, and an inclined portion is formed to extend inclined from the radially inner to the radially outer, A dust cover characterized by having the following features.

2. A dust cover according to claim 1, A dust cover characterized in that the second end and the third end have an outer diameter larger than that of the cylindrical portion.

3. A dust cover according to claim 1 or 2, The first wall portion is inclined such that the first end is located axially toward the other end than the second end. The dust cover is characterized in that the second wall portion is inclined such that the fourth end portion is located axially toward one end portion than the third end portion.

4. A dust cover according to claim 1 or 2, The dust cover is characterized in that the inclined portion has a notch formed to extend radially inward from the radially outer end.

5. A cylinder in which the working fluid is sealed, A piston rod with one end protruding from the cylinder, A flange portion is provided at one end of the piston rod, which protrudes radially outward, A dust cover, one end of which is fixed to the flange portion and the other end of which is fixed to the cylinder, A band for securing the dust cover to the flange portion, A shock absorber equipped with, The dust cover has a bellows section having peaks and valleys, A first end is formed at the axial end of the bellows section, and is formed to extend from the radially inward to the radially outward, and a first wall portion is formed to abut against the first contact surface at the other axial end of the flange portion, A cylindrical portion is connected to a second end formed at the radially outer end of the first wall portion, and has a recess formed therein where at least a portion in the axial direction is recessed radially inward in its natural state, and abuts against the radially outer side of the flange portion, A third end is formed at the axial end of the cylindrical portion, and is formed to extend from the radially outer side to the radially inner side, and a second wall portion is formed to abut the second contact surface at the axial end of the flange portion, It has a fourth end formed at the radially inner end of the second wall portion, and an inclined portion formed to extend inclined from the radially inner to the radially outer, The buffer is characterized in that the band is provided on the radially outer side of the cylindrical portion.

6. A buffer according to claim 5, The buffer is characterized in that the first wall portion is inclined such that the first end is located closer to the first contact surface than the second end.

7. A buffer according to claim 5 or 6, The buffer is characterized in that the second wall portion is inclined such that the fourth end portion is located closer to the second contact surface than the third end portion.

8. A buffer according to claim 5 or 6, The shock absorber is characterized in that the second contact surface is inclined such that the radially inner side is located axially closer to the other end than the radially outer side.

9. A buffer according to claim 5 or 6, The flange portion has a thin-walled portion formed at the radially outer end, a thick-walled portion that is longer in the axial direction than the thin-walled portion, and an annular stepped portion formed between the thin-walled portion and the thick-walled portion. The dust cover is a buffer characterized in that the fourth end abuts against the stepped portion.

10. A buffer according to claim 5 or 6, The dust cover is a buffer characterized in that the second end and the third end have an outer diameter larger than that of the cylindrical portion.

11. A buffer according to claim 5 or 6, The dust cover is characterized by having a notch formed to extend radially inward from the radially outer end of the inclined portion.

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