Sealing member and shock absorber

Abstract

The dust-proof member (10) of the sealing member (S) has: a first inner peripheral surface (11) which is reduced in diameter toward the base end side; a second inner peripheral surface (12) that expands in diameter toward the base end side; a dust lip (14) formed at a connection portion between the first inner peripheral surface (11) and the second inner peripheral surface (12); and a rigidity reduction part which is provided closer to the base end side than the dustproof lip part (14), the rigidity reduction part (R) being located closer to the tip end side of the dustproof material (10) than an end surface (40a) on the dustproof lip part (14) side of the core body (40), and the end surface (40a) on the dustproof lip part (14) side of the core body (40) in the axial direction being located closer to the base end side than the middle of the dustproof lip part (14).

Description

Technical Field

[0001] This invention relates to sealing components and buffers. Background Technology

[0002] In fluid pressure devices such as buffers, a sealing component is known to seal the gap between a cylinder and a rod (Japanese Utility Model Publication JPH5-38433U). In the sealing component described in JPH5-38433U, a base portion (reinforcing ring) made of a metal material is held in the cylinder, and a dustproof lip made of an elastomer such as rubber is provided in the base portion (reinforcing ring) in a manner that allows it to slide in contact with the rod. Summary of the Invention

[0003] In the sealing component described in JPH5-38433U, the opening on the top side of the inner circumferential surface of the dustproof lip has a generally boundary shape. When this type of sealing component is installed on a shock absorber, dust adhering to the outer circumferential surface of the rod when the rod retracts can be effectively removed, thus providing good dust resistance to prevent dust intrusion.

[0004] However, in the shape of the sealing component described in JPH5-38433U, the surface pressure at the dust lip rises sharply from the top side. Specifically, the opening on the top side (with the top side of the sealing component of the rod) becomes a boundary shape. Therefore, when the rod contracts, the oil film adhering to the outer circumferential surface of the rod is scraped off, and oil leakage is likely to occur.

[0005] Therefore, to prevent oil leakage, it is possible to reduce the surface pressure gradient at the dustproof lip, specifically by reducing the angle of the top surface of the dustproof lip. However, even with this reduction in the angle of the top surface of the dustproof lip, the high rigidity of the dustproof component makes it impossible to maintain the reduced surface pressure gradient. Consequently, the desired surface pressure gradient cannot be achieved, and leakage cannot be prevented.

[0006] The present invention addresses the aforementioned problems by providing a sealing component capable of achieving a desired surface pressure gradient and suppressing leakage.

[0007] According to one aspect of the present invention, a sealing member disposed in a fluid pressure device and sealing between a cylinder and a rod comprises: a core; a dustproof member having a base end fixed to the core and extending toward the rod, and slidingly contacting the outer peripheral surface of the rod, the dustproof member having: a first inner peripheral surface that is narrower toward the base end; a second inner peripheral surface formed on the base end side compared to the first inner peripheral surface and wider toward the base end; a dustproof lip formed at the connection portion of the first inner peripheral surface and the second inner peripheral surface; and a rigidity reduction portion disposed on the base end side compared to the dustproof lip, the rigidity reduction portion being located on the top end side of the dustproof member compared to the end face of the dustproof lip side of the core, and the end face of the dustproof lip side of the core located axially being closer to the base end side than the middle of the dustproof lip. Attached Figure Description

[0008] Figure 1 A partial cross-sectional view of a buffer for which the sealing component according to embodiments of the present invention can be applied.

[0009] Figure 2 This is an enlarged cross-sectional view of the sealing component according to an embodiment of the present invention.

[0010] Figure 3 This is an enlarged cross-sectional view of the dustproof component of the sealing member according to an embodiment of the present invention.

[0011] Figure 4 This is an enlarged cross-sectional view of the dustproof component of the sealing element involved in the comparative example.

[0012] Figure 5(A) is a diagram showing the distribution of surface pressure in a dustproof component with the sealing member according to the embodiment of the present invention installed in the buffer 100. Figure 5(B) is a diagram showing the distribution of surface pressure in a dustproof component with the sealing member according to the comparative example installed in the buffer 100. Detailed Implementation

[0013] Hereinafter, the sealing component S according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] Figure 1 This is a partial cross-sectional view of a damper 100, which is a fluid pressure device in which a sealing component S can be applied. The damper 100 is, for example, disposed between the body and axle of a vehicle (not shown) and generates damping force to suppress vibration of the body.

[0015] The buffer 100 includes a cylinder 1, a rod 2 that is freely inserted into the cylinder 1, and a piston 3 connected to the rod 2. The piston 3 is housed in the cylinder 1 in a freely sliding manner, dividing the cylinder 1 into a pressure-side chamber 1a and an extension-side chamber 1b. A working fluid, which serves as the working fluid, is sealed into the pressure-side chamber 1a and the extension-side chamber 1b.

[0016] On the piston 3, a pressure-side passage 3a and an extension-side passage 3b are formed, connecting the pressure-side chamber 1a and the extension-side chamber 1b. The pressure-side passage 3a and the extension-side passage 3b are opened and closed respectively by a pressure-side attenuation valve 4a and an extension-side attenuation valve 4b provided on the piston 3 as attenuation force generating parts.

[0017] Rod 2 extends from cylinder 1 through extension chamber 1b. Rod 2 enters cylinder 1 to retract buffer 100, and rod 2 exits cylinder 1 to extend buffer 100.

[0018] When the buffer 100 contracts, the piston 3 moves in the direction of shrinking the pressure-side chamber 1a and expanding the extension-side chamber 1b. The pressure-side attenuation valve 4a opens due to the pressure difference between the pressure-side chamber 1a and the extension-side chamber 1b, opening the pressure-side passage 3a. Working fluid flows from the pressure-side chamber 1a into the extension-side chamber 1b through the pressure-side passage 3a. At this time, the flow of the working fluid is resisted by the pressure-side attenuation valve 4a, and the buffer 100 exerts its attenuation force.

[0019] When the buffer 100 extends, the piston 3 moves in the direction of shrinking the extension chamber 1b and expanding the pressure chamber 1a. The extension attenuation valve 4b opens due to the pressure difference between the extension chamber 1b and the pressure chamber 1a, opening the extension passage 3b. Working fluid flows from the extension chamber 1b into the pressure chamber 1a through the extension passage 3b. At this time, the flow of the working fluid is resisted by the extension attenuation valve 4b, and the buffer 100 exerts its attenuation force.

[0020] In this way, the pressure-side attenuation valve 4a and the extension-side attenuation valve 4b, along with the movement of rod 2, exert resistance on the flow of the working fluid, thereby generating attenuation force.

[0021] The volume change in cylinder 1 caused by the movement of rod 2 is compensated by the air chamber 1c formed by the free piston 5 within cylinder 1.

[0022] A rod guide 6 is provided on the inner circumference of cylinder 1, separated by a bushing 6a, to support rod 2 so that it can slide freely. The rod guide 6 is supported by a retaining ring 6b provided on the inner circumference of cylinder 1.

[0023] The open end 1d of cylinder 1 is bent radially inward by riveting. A sealing member S is provided between the open end 1d and the rod guide 6 to close the gap between cylinder 1 and rod 2. That is, the sealing member S and the rod guide 6 are clamped and fixed to cylinder 1 by the open end 1d of cylinder 1 and the retaining ring 6b.

[0024] like Figure 2As shown, the sealing component S includes: an annular dust seal 10, which is disposed on the top end of the rod 2 and slides in contact with the outer peripheral surface of the rod 2; an oil seal 30, which is disposed on the opposite side of the dust seal 10 in the axial direction of the rod 2; a cylindrical connecting portion 20, which connects the dust seal 10 and the oil seal 30; and a core 40, which is disposed on the radially outer side of the connecting portion 20 and is used to fix the base end of the dust seal 10 and the base end of the oil seal 30.

[0025] The dustproof component 10 scrapes off foreign objects adhering to the outer peripheral surface of the rod 2 when the buffer 100 retracts. That is, the dustproof component 10 prevents foreign objects from entering the cylinder 1. In addition, the dustproof component 10 in this embodiment does not use force-applying components such as a garter spring, but only relies on its own elasticity to seal between itself and the rod 2.

[0026] The oil seal 30 is formed to protrude radially inward from the connecting portion 20 and in the contraction direction of the rod 2, and slides in contact with the outer peripheral surface of the rod 2. When the buffer 100 extends, the working fluid adhering to the outer periphery of the rod 2 is scraped off by the oil seal 30 and returned to the cylinder 1. That is, the oil seal 30 prevents the working fluid from leaking out of the cylinder 1.

[0027] An annular groove 31 is formed on the outer periphery of the oil seal 30, and an annular helical spring 32 is installed on the groove 31. The annular helical spring 32 ensures the sealing performance of the rod 2 in the oil seal 30.

[0028] The sealing component S also includes an outer peripheral sealing portion 50 that extends axially in an annular shape from the outer edge of the oil seal 30 along the inner circumference of the cylinder 1. The outer peripheral sealing portion 50 closes the gap between the outer circumference of the core 40 and the inner circumference of the cylinder 1, and prevents leakage of working fluid and intrusion of foreign matter in the gap.

[0029] The dustproof component 10, the connecting part 20, the oil seal 30, and the outer peripheral sealing part 50 are integrally formed of rubber material. As the rubber material, for example, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluororubber (FKM), and polyurethane rubber (AU, EU) can be used.

[0030] Furthermore, the core 40 is a ring-shaped plate made of metal material, and is integrated with the dustproof component 10, the connecting part 20, and the oil seal component 30 by vulcanization bonding. In this embodiment, a portion of the core 40 is exposed from the rubber material; however, the entire core 40 may also be embedded in the rubber material.

[0031] Next, refer to Figure 3 The specific shape of the dustproof component 10 is described.

[0032] The dustproof component 10 has: a cover portion 10A as a base end, which extends along the end face 40a on the extension direction side of the rod 2 of the core body 40; and an annular protrusion 10B (see reference). Figure 2 The protrusion 10B is formed in a manner that protrudes in the extension direction of the rod 2 at the outer edge of the covering portion 10A; the lip 10C is formed in a manner that protrudes radially inward from the covering portion 10A and in the extension direction of the rod 2, and slides in contact with the outer periphery of the rod 2; the recess 10D is formed between the protrusion 10B and the lip 10C.

[0033] The inner circumferential surface of the dustproof member 10 is composed of a first inner circumferential surface 11, a second inner circumferential surface 12, a third inner circumferential surface 13, and a fourth inner circumferential surface 16, which are sequentially arranged from the top end side. Specifically, the dustproof member 10 (lip 10C) has: a first inner circumferential surface 11, which narrows from the top end surface 10a toward the base end side; a second inner circumferential surface 12, which is formed on the base end (covered portion 10A) side of the first inner circumferential surface 11 and widens toward the base end side; a third inner circumferential surface 13, which is formed on the base end side of the second inner circumferential surface 12 and widens toward the base end side; a dustproof lip 14, which is formed at the connection portion of the first inner circumferential surface 11 and the second inner circumferential surface 12; a curved portion 15, which is formed at the connection portion of the second inner circumferential surface 12 and the third inner circumferential surface 13; and a support portion 17, which is formed at the connection portion of the third inner circumferential surface 13 and the fourth inner circumferential surface 16.

[0034] The fourth inner circumferential surface 16 is formed in a manner that is continuous with the cylindrical inner circumferential surface 20a of the connecting portion 20.

[0035] The first inner circumferential surface 11 is formed by a curved surface that bulges radially inward. Alternatively, the first inner circumferential surface 11 can also be formed as a plane (with a certain angle of inclination), or a combination of a plane and a curved surface can be formed.

[0036] The second inner circumferential surface 12 is formed as a plane that expands in diameter toward the base end at a certain inclination angle θ2. Alternatively, the second inner circumferential surface 12 can also be formed as a curved surface, or a combination of a plane and a curved surface can be formed.

[0037] The third inner circumferential surface 13 is formed by a curved surface that is concave outward in the radial direction. Alternatively, the third inner circumferential surface 13 can also be formed as a plane (with a certain angle of inclination), or a combination of a plane and a curved surface can be formed.

[0038] The axial length L1 of the first inner circumferential surface 11 is formed to be approximately equal to the axial length L3 of the third inner circumferential surface 13, and the axial length L2 of the second inner circumferential surface 12 is formed to be longer than the axial length L1 of the first inner circumferential surface 11 and the axial length L3 of the third inner circumferential surface 13. Preferably, the first inner circumferential surface 11, the second inner circumferential surface 12, and the third inner circumferential surface 13 are formed in a ratio of length L1, length L2, and length L3 of 1:4:1.

[0039] The tilt angle θ1 of the top side of the dustproof lip 14 is set to approximately 1° to 10°. The tilt angle θ1 mentioned here refers to the angle between the dustproof lip 14 and the central axis of the rod 2 (see reference). Figure 1 as well as Figure 2 The angle between the parallel line ○1 and the first inner circumferential surface 11. Furthermore, the tilt angle θ2 on the base side of the dustproof lip 14 is set to approximately 10° to 20°. The tilt angle θ2 mentioned here refers to the angle between the line ○1 and the second inner circumferential surface 12 at the dustproof lip 14.

[0040] The tilt angle θ3 at the base end of the curved portion 15 is set to approximately 30° to 90°. The tilt angle θ3 mentioned here refers to the angle formed by line ○1 at the curved portion 15 and the third inner circumferential surface 13.

[0041] Furthermore, the tilt angle θ1 will be referred to as the tilt angle of the first inner circumferential surface 11, the tilt angle θ2 will be referred to as the tilt angle of the second inner circumferential surface 12, and the tilt angle θ3 will be referred to as the tilt angle of the third inner circumferential surface 13.

[0042] In the sealing component S of this embodiment, the radial thickness T1 in the regions of the first inner peripheral surface 11 and the second inner peripheral surface 12 of the dustproof component 10 is set to be more than half and less than the sum of the length L1 of the first inner peripheral surface 11 and the axial length L2 of the second inner peripheral surface 12.

[0043] The dustproof part 10 also has a rigidity reduction part R that is provided on the base end side compared to the dustproof lip 14.

[0044] The rigidity reduction portion R is located on the top side of the dustproof member 10, relative to the end face 40a on the dustproof lip 14 side of the core 40, and is located axially between the end face 40a on the dustproof lip 14 side of the core 40 and the dustproof lip 14 (refer to...). Figure 3 The midpoint M) is closer to the base side.

[0045] In this embodiment, the rigidity reduction portion R is formed by making the radial thickness T3 of the dustproof member 10 thinner than the radial thickness T2 in the bending portion 15 in the region where at least the third inner circumferential surface 13 is provided.

[0046] Next, the function and effect of the dustproof component 10 thus constructed will be explained with reference to a comparative example. Figure 4 This is an enlarged cross-sectional view of the dustproof member 110 of the sealing member S1 involved in the comparative example. In addition, FIG5(A) is a diagram showing the surface pressure distribution of the dustproof member 10 with the sealing member S involved in this embodiment installed in the buffer 100, and FIG5(B) is a diagram showing the surface pressure distribution of the dustproof member 110 with the sealing member S1 involved in the comparative example installed in the buffer 100.

[0047] Figure 4 The opening at the top end of the inner circumferential surface of the dustproof member 110 of the sealing member S1 (and the sealing member of the rod 2) forms a boundary shape. When this type of sealing member S1 is installed in the buffer 100, the distribution of surface pressure in the dustproof member 110 is shown in Figure 5(B). As can be seen from Figure 5(B), in the sealing member S1, the surface pressure increases sharply (the gradient becomes steeper) from the top end of the dustproof member 110 toward the base end.

[0048] Because in Figure 4 In the dustproof component 110 of the sealing component S1 shown, the opening on the top surface 110a side has a boundary shape. Therefore, when the rod 2 retracts, the oil film adhering to the outer peripheral surface of the rod 2 is scraped off, making oil leakage easy to occur. Therefore, in order to prevent oil leakage, it is advisable to reduce the gradient of the surface pressure at the dustproof component 110. Specifically, the top surface 110a of the dustproof component 110 is inclined in the retraction direction of the rod 2 as it moves radially inward.

[0049] However, when the top surface 110a of the dustproof member 110 is tilted in this way, the gradient of the surface pressure from the top of the dustproof member 110 toward the base end becomes smaller, but the peak value P1 of the surface pressure may decrease. Furthermore, when the peak value P1 of the surface pressure decreases, the maximum value of the pressing force of the dustproof member 110 against the rod 2 decreases, and therefore, the dust resistance that prevents dust adhering to the rod 2 from entering the cylinder 1 may deteriorate.

[0050] Furthermore, when the top surface 110a of the dustproof component 110 is tilted as described above, the peak value P1 of the surface pressure shifts to the left in Figure 5(B), and the distribution of the surface pressure becomes symmetrical. When the distribution of the surface pressure becomes symmetrical, a shaking phenomenon may occur where the contact portion of the dustproof component 110 that contacts the rod 2 deforms due to the reciprocating movement of the rod 2. This shaking phenomenon may cause the oil film thickness on the outer peripheral surface of the rod 2 to become unstable, and lead to a reduction in the lifespan of the dustproof component 110.

[0051] Therefore, in the sealing member S of this embodiment, a first inner circumferential surface 11, a second inner circumferential surface 12, and a third inner circumferential surface 13 as described above are provided. By providing a first inner circumferential surface 11 that tapers in diameter from the top surface 10a of the dustproof member 10 toward the base end, as shown in FIG. 5(A), the gradient of surface pressure from the top surface of the dustproof member 10 toward the base end can be reduced (gradualized) (refer to the portion shown by CL in FIG. 5(A)). In addition, in the sealing member S of this embodiment, a peak surface pressure P is generated near the dustproof lip 14.

[0052] Furthermore, in the sealing member S of this embodiment, the second inner circumferential surface 12 is formed with different inclination angles θ2 and θ3 of the third inner circumferential surface 13. In other words, the inner circumferential surface of the dustproof member 10 is formed such that it bends at the bend 15. By setting the inner circumferential surface of the dustproof member 10 to this shape, as shown in FIG5(A), the surface pressure distribution can be set to an asymmetrical shape centered on the peak value P. Therefore, the head-shaking phenomenon that occurs in the contact portion of the dustproof member 10 that contacts the rod 2, which accompanies the reciprocating movement of the rod 2, can be suppressed.

[0053] Furthermore, in the sealing member S of this embodiment, the third inner peripheral surface 13 is located radially outward compared to the extension surface 12a on the extension line of the second inner peripheral surface 12, and the connection portion (support portion 17) between the third inner peripheral surface 13 and the fourth inner peripheral surface 16 is located closer to the top end of the dustproof member 10 compared to the end face 40a on the dustproof member 10 side of the core 40. By setting the lip 10C of the dustproof member 10 in this shape, the thickness near the third inner peripheral surface 13 can be reduced. In other words, the sealing member S of this embodiment has a rigidity reduction portion R in the area where the third inner peripheral surface 13 is provided, formed by making the radial thickness T3 of the dustproof member 10 thinner than the thickness T2 in the bending portion 15. Furthermore, in the sealing member S of this embodiment, the rigidity reduction portion R is provided at a position separated from the core 40, which serves as a reinforcing member, and more specifically, it is provided closer to the base end side compared to the middle of the end face 40a on the dustproof lip 14 side of the core 40 in the axial direction. Therefore, in the sealing component S of this embodiment, with Figure 4 Compared to the shape of the comparative example dustproof member 110, the rigidity of the base end side of the lip 10C of the dustproof member 10 can be reduced. This increases the stress on the portion of the dustproof member 10 pressed against the rod 2 (near the dustproof lip 14), thus suppressing a decrease in the peak value P of the surface pressure.

[0054] Therefore, the sealing member S according to this embodiment can maintain the peak value P of the surface pressure of the dustproof member 10 while suppressing leakage. In addition, the leaked working fluid is captured by the recess 10D, thereby preventing further expansion of the working fluid.

[0055] Furthermore, in the sealing component S, by setting the radial thickness T1 of the first inner circumferential surface 11 and the second inner circumferential surface 12 of the dustproof component 10 to be more than half and less than the sum of the axial lengths (lengths L1 and L2) of the first inner circumferential surface 11 and the second inner circumferential surface 12, it is possible to further reliably ensure the rigidity of the dustproof component 10 near the dustproof lip 14 where the peak surface pressure P is generated, and further reliably ensure the elasticity of the dustproof component 10.

[0056] Furthermore, in the sealing component S, it is more preferable that the axial length L1 of the first inner circumferential surface 11 is approximately equal to the axial length L3 of the third inner circumferential surface 13, and the axial length L2 of the second inner circumferential surface 12 is longer than the respective axial lengths L1 and L3 of the first inner circumferential surface 11 and the third inner circumferential surface 13, and the dustproof component 10 is formed in the ratio of lengths L1:L2:L3=1:4:1.

[0057] By shaping the dustproof component 10 in this way, it is possible to reliably make the distribution of surface pressure asymmetrical and to reliably ensure the dust resistance required for the dustproof component 10.

[0058] Furthermore, in the sealing component S, it is more preferable that the inclination angle θ2 of the second inner circumferential surface 12 is greater than the inclination angle θ1 of the first inner circumferential surface 11, and the inclination angle θ3 of the third inner circumferential surface 13 is greater than the inclination angle θ2 of the second inner circumferential surface 12, and the dustproof component 10 is formed with the inclination angle θ1 of the first inner circumferential surface 11 being 1° to 10° (range), the inclination angle θ2 of the second inner circumferential surface 12 being 10° to 20° (range), and the inclination angle θ3 of the third inner circumferential surface 13 being 60° to 90° (range).

[0059] By shaping the dustproof component 10 in this way, it is possible to reliably make the distribution of surface pressure asymmetrical and to reliably ensure the dust resistance required for the dustproof component 10.

[0060] Furthermore, in the sealing component S of this embodiment, the dustproof component 10 is constructed to seal the cylinder 1 and rod 2 solely using its own elasticity. This eliminates the need for components such as annular coil springs, reducing the number of parts required.

[0061] Furthermore, for example, when the stiffness-reducing portion R is positioned axially close to the core 40 (e.g., near the connecting portion 20), the core 40 prevents the stiffness-reducing portion R from functioning sufficiently. Specifically, the dustproof member 10 deforms starting from the support portion 17; however, when the support portion 17 is located radially inward of the core 40, the core suppresses the deformation of the lip 10C starting from the support portion 17, resulting in excessive stiffness. As a result, the desired surface pressure gradient cannot be maintained.

[0062] Conversely, when the rigidity reduction portion R is positioned on the top side of the dustproof member 10 relative to the midpoint M, the rigidity is insufficient, resulting in excessive deformation. Specifically, the support portion 17 is located near the dustproof lip 14, therefore, the rigidity is insufficient, and the lip 10C is prone to excessive deformation. As a result, the desired surface pressure gradient cannot be maintained. Furthermore, when the rigidity reduction portion R is positioned on the top side of the dustproof member 10 relative to the midpoint M, the area of ​​the sliding portion of the dustproof member 10 may also be restricted, thus reducing design freedom.

[0063] Therefore, as in this embodiment, by providing the rigidity reduction portion R at the top end of the dustproof member 10 compared to the end face 40a of the dustproof lip 14 side of the core 40, and at the base end side compared to the middle of the dustproof lip 14 side of the end face 40a of the dustproof lip 14 side of the core 40 in the axial direction, the desired surface pressure gradient can be maintained.

[0064] Furthermore, preferably, in the sealing member S, the position formed by extending the end face of the dustproof lip 14 side of the covered portion 10A in the axial direction is set within the range of the rigidity reduction portion R. More preferably, the position of the end face 10b of the dustproof lip 14 side of the covered portion 10A in the axial direction is equal to the position of the end (support portion 17) of the base end side of the third inner peripheral surface 13 in the axial direction. In this way, the desired surface pressure gradient can be maintained more reliably.

[0065] The structure, function, and effects of the embodiments of the present invention are summarized and explained below.

[0066] The sealing component S includes: a core 40; a dustproof member 10, which has a base end fixed on the core 40 and extends toward the rod 2, and slides in contact with the outer peripheral surface of the rod 2. The dustproof member 10 has: a first inner peripheral surface 11, which is narrowed toward the base end; a second inner peripheral surface 12, which is formed on the base end side compared to the first inner peripheral surface 11 and is widened toward the base end; a dustproof lip 14, which is formed at the connection between the first inner peripheral surface 11 and the second inner peripheral surface 12; and a rigidity reduction portion R, which is provided on the base end side compared to the dustproof lip 14. The rigidity reduction portion R is located on the top end side of the dustproof member 10 compared to the end face 40a of the dustproof lip 14 side of the core 40, and is located on the base end side compared to the middle of the dustproof lip 14 side of the core 40 in the axial direction.

[0067] Since the dustproof lip 14 is formed at the connection between the first inner circumferential surface 11 and the second inner circumferential surface 12 in this structure, the surface pressure can be reduced by adjusting the angle between the first inner circumferential surface 11 and the second inner circumferential surface 12. Furthermore, in this structure, the rigidity reduction portion R is located closer to the top end of the dustproof member 10 than the end face 40a of the dustproof lip 14 side of the core 40, and the end face 40a of the dustproof lip 14 side of the core 40 located axially is closer to the base end than the middle of the dustproof lip 14. Therefore, the rigidity of the dustproof member 10 is neither excessively high nor excessively low, thus maintaining the desired surface pressure gradient. In this way, leakage can be suppressed while maintaining the peak surface pressure P of the dustproof member 10.

[0068] In the sealing component S, the dustproof component 10 has: a third inner peripheral surface 13, which is formed on the base end side compared to the second inner peripheral surface 12 and expands in diameter toward the base end side; a bend 15, which is formed at the connection between the second inner peripheral surface 12 and the third inner peripheral surface 13, and the rigidity reduction portion R is formed by making the radial thickness T3 of the dustproof component 10 thinner than the radial thickness T2 in the bend 15 in the region where at least the third inner peripheral surface 13 is provided.

[0069] In this structure, the rigidity reduction section R is formed simply by changing the thickness of the dustproof part 10, thus suppressing the increase in cost caused by forming the rigidity reduction section R.

[0070] In the sealing component S, the base end of the dustproof component 10 has a covering portion 10A extending along the end face of the dustproof lip 14 side of the core 40. The position of the axial end face 10b of the covering portion 10A on the dustproof lip 14 side is equal to the position of the axial end end (support portion 17) of the third inner peripheral surface 13 on the base end side. In addition, the position formed by extending the axial end face of the covering portion 10A on the dustproof lip 14 side is only required to be within the range of the rigidity reduction portion R.

[0071] In this structure, the rigidity of the dustproof component 10 is neither excessively high nor excessively low, thus maintaining the desired surface pressure gradient. This allows for the maintenance of the peak surface pressure P of the dustproof component 10 while suppressing leakage.

[0072] In the sealing component S, the tilt angle θ2 of the second inner circumferential surface 12 is greater than the tilt angle θ1 of the first inner circumferential surface 11, and the tilt angle θ3 of the third inner circumferential surface 13 is greater than the tilt angle θ2 of the second inner circumferential surface 12.

[0073] In this structure, the distribution of surface pressure can be reliably set to asymmetry, thus suppressing the head-shaking phenomenon that occurs in the contact portion of the dustproof member 10 that contacts the rod 2 (near the dustproof lip 14) as the rod 2 reciprocates. Furthermore, by setting the dustproof member 10 in this shape, the required dust resistance of the dustproof member 10 can be reliably ensured.

[0074] The buffer 100 includes: a sealing component S; a cylinder into which the working fluid is sealed; a rod 2 that is inserted into the cylinder 1 in a manner that allows free movement in the axial direction; a pressure-side attenuation valve 4a and an extension-side attenuation valve 4b (attenuation force generating part), which are housed in the cylinder 1 and, with the movement of the rod 2, apply resistance to the flow of the working fluid to generate attenuation force.

[0075] The embodiments of the present invention have been described above. However, the above embodiments are merely some examples of the application of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0076] Although a working fluid was used as the working fluid in the above embodiments, incompressible fluids such as water or aqueous solutions can also be used instead of the working fluid.

[0077] Although the above embodiment describes a single-cylinder type buffer 100 as having a pressure-side chamber 1a, an extension-side chamber 1b, and an air chamber 1c formed inside the cylinder 1, the buffer 100 may also be a multi-cylinder type buffer with an outer tube provided around the outer periphery of the inner tube that serves as the cylinder, and a reservoir formed between the inner tube and the outer tube.

[0078] Furthermore, although the sealing component S used in the buffer 100 has been described in the above embodiment, the present invention can also be applied to sealing components used in fluid pressure equipment such as fluid pressure cylinders.

[0079] Although the above embodiment describes the sealing member S as an example with a dustproof member 10 and an oil seal 30, the sealing member S may also be a structure without the oil seal 30.

[0080] The rigidity-reducing portion R is not limited to the embodiments described herein, and various methods for reducing rigidity can be used. For example, the rigidity-reducing portion R can be formed by extending the second inner circumferential surface 12 to connect it to the connecting portion 20 or the fourth inner circumferential surface 16, and providing a groove in the extended portion of the second inner circumferential surface 12; or, the extended portion of the second inner circumferential surface 12 can be formed using other materials that are easily elastically deformable. Alternatively, the rigidity-reducing portion R can be formed by containing PTFE fibers in the sealing member S and adjusting their orientation.

[0081] This application claims priority based on Japanese Patent Application No. 2023-170266 filed with the Japan Patent Office on September 29, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A sealing component disposed in a fluid pressure device and used to seal between a cylinder and a rod, wherein, The sealing component includes: Core; A dustproof component, having a base end fixed to the core and extending toward the rod, and slidingly contacting the outer peripheral surface of the rod. The dustproof component has: The first inner circumferential surface is tapered toward the base end side; A second inner circumferential surface is formed on the base end side compared to the first inner circumferential surface, and its diameter is expanded toward the base end side; A dustproof lip is formed at the connection between the first inner circumferential surface and the second inner circumferential surface; A rigidity reduction portion is provided on the base end side compared to the dustproof lip portion. The rigidity reduction portion is located closer to the top end of the dustproof member than the end face of the dustproof lip side of the core, and the end face of the dustproof lip side of the core located axially is closer to the base end side than the middle of the dustproof lip.

2. The sealing component as claimed in claim 1, wherein, The dustproof component has: A third inner circumferential surface is formed on the base end side compared to the second inner circumferential surface, and its diameter is expanded toward the base end side; A curved portion is formed at the connection between the second inner circumferential surface and the third inner circumferential surface. The rigidity reduction portion is formed by making the radial thickness of the dustproof member thinner than the radial thickness in the bending portion in the region where at least the third inner circumferential surface is provided.

3. The sealing component as claimed in claim 1, wherein, The base end of the dustproof component has a covered portion extending along the end face of the dustproof lip side of the core. The position formed by extending the end face of the dustproof lip side in the axial direction of the covered part is within the range of the rigidity reduction part.

4. The sealing component as claimed in claim 2, wherein, The inclination angle of the second inner circumferential surface is greater than the inclination angle of the first inner circumferential surface. The inclination angle of the third inner circumferential surface is greater than the inclination angle of the second inner circumferential surface.

5. A buffer, wherein, have: The sealing component as claimed in claim 1; The cylinder is used to seal in the working fluid; The rod is inserted into the cylinder in a manner that allows it to move freely in the axial direction; The damping force generating unit, which is housed in the cylinder, applies resistance to the flow of the working fluid as the rod moves, thereby generating a damping force.

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