Seal member

Abstract

Provided is a seal member which is capable of offering, over a long time, a maximum contact surface pressure and a contact surface pressure gradient that are necessary and sufficient for scrubbing off foreign matter and foreign liquid. A seal member is provided with: a body (51); and an elastic lip part (52) which extends obliquely from the body (51) toward an opposing surface (12) and is in slide-contact with the opposing surface (12) with interference therebetween. A surface (53) of the lip part (52) facing the opposing surface (12) has a texture structure in which a plurality of ribs (55) extending in a direction orthogonal to a seal contour direction, which is a direction separating a gap closed by the seal member (50) into the inner side and the outer side, are arranged consecutively in the seal contour direction. In a free state of the seal member (50), the top portions of the plurality of ribs (55) are positioned within the range of the interference D.

Description

Sealing member

[0001] The present invention relates to a sealing member used for a linear motion device.

[0002] For example, in a reciprocating lip seal having a clamping allowance used in a linear guide, by setting a necessary and sufficient surface pressure gradient and a maximum surface pressure at the contact portion between the lip tip and the rail as viewed from the moving direction of the slider, a minimum oil film thickness that prevents foreign matter from entering is obtained, and the performance of scraping foreign matter (scraping performance) is obtained.

[0003] On the other hand, a linear guide may be used in a harsh foreign matter environment. For example, a cutting coolant may wash away the lubricant for the linear guide, wood processing powder may absorb the lubricant for the linear guide, or minute foreign matter may be sandwiched between the lip and the rail, and the formation of an oil film with an appropriate thickness may be inhibited due to an increase in the local surface pressure gradient.

[0004] In such a foreign matter environment, the lip seal for a linear guide may not be able to maintain fluid film lubrication temporarily or permanently on the sliding surface with the rail, and may be in a mixed lubrication or boundary lubrication condition, resulting in early progress of lip wear. Specifically, in a conventional lip seal, there is a problem that the pressing force decreases due to a decrease in the clamping allowance due to wear, resulting in a decrease in the maximum contact surface pressure of the lip, and a decrease in the foreign matter intrusion prevention effect of the lip seal. In addition, as the maximum contact surface pressure decreases, the surface pressure gradient when viewed from the moving direction of the slider of the contact surface pressure distribution of the lip seal decreases, and there is a risk that the oil film thickness generated between the lip seal surface and the contact surface of the rail becomes thick and foreign matter of the same size as the oil film thickness passes through.

[0005] For example, Patent Document 1 discloses a sealing member that closes the gap between a moving member and a track axis. The sealing member has multiple grooves formed on the sealing surface facing the track axis, extending in a direction perpendicular to the direction of movement of the moving member. The sealing surface is divided into minute protrusions (ribs) that contact the track axis, which allows for smooth operation of the moving member and provides a sufficient sealing effect. Patent Document 2 describes how setting a small inclination angle on the atmospheric contact surface of the sealing lip provides a flat portion on the atmospheric contact surface, suppressing the peak of contact pressure and improving wear resistance. It also describes how a multi-stage rib structure is provided on the flat portion, and the height of each rib is gradually increased from the sealed fluid side to the atmospheric side of the rib structure to improve lubricity and stabilize the contact state.

[0006] Furthermore, Patent Document 3 discloses a lip-type seal in which notches are formed on the sliding surface of a plate-shaped lip or on the inclined sliding surface of an inner circumferential lip to reduce stress concentration, improve the safety factor against fracture, and suppress the decrease in sealing performance due to reduced creep.

[0007] Japanese Patent Publication No. 2010-84811 Japanese Patent Publication No. 2003-322260 Japanese Patent No. 4877460

[0008] Incidentally, in Patent Documents 1 and 2, sufficient sealing effect is achieved between the track axis and the moving member by increasing the number of ribs that contact the rail perpendicular to the slider's direction of travel. However, excessive scraping of lubricant by the multi-stage ribs leads to an increase in the seal friction coefficient, accelerating seal wear, which may result in insufficient seal and linear guide lifespan. Furthermore, in Patent Document 3, a spring is required for the sliding contact of the seal lip, resulting in a configuration with a large number of parts. Moreover, Patent Documents 1 to 3 do not mention how to maintain sealing performance when the lip is worn.

[0009] The present invention has been made in view of the aforementioned problems, and its purpose is to provide a sealing member that can obtain a maximum contact pressure and a contact pressure gradient necessary and sufficient for sweeping away foreign matter and foreign liquids over a long period of time.

[0010] Accordingly, the above object of the present invention is achieved by the following configuration [1] relating to the sealing member. [1] A sealing member attached to a moving member so as to close a gap between a fixed member and a moving member that moves relative to the fixed member, and sliding in contact with an opposing surface provided on the fixed member, comprising: a main body portion and an elastic lip portion extending diagonally from the main body portion toward the opposing surface and sliding in contact with the opposing surface with an overlap, wherein the surface of the lip portion facing the opposing surface has a texture structure in which a plurality of ribs are continuously arranged in a direction perpendicular to the seal contour direction, which is the direction in which the gap that the sealing member closes is divided into the inside and the outside, and the tops of the plurality of ribs are located within the overlap range in the free state of the sealing member.

[0011] According to the sealing member of the present invention, boundary lubrication occurs, and even if the maximum contact pressure and the gradient of the contact pressure decrease as lip wear progresses and sealing performance deteriorates, the adjacent unworn rib slides against the opposing surface, thereby maintaining a maximum contact pressure and a gradient of the contact pressure that is necessary and sufficient to sweep away foreign matter and foreign liquids over a long period of time.

[0012] Figure 1(a) is a front view of a linear guide including a sealing member according to one embodiment of the present invention, Figure 1(b) is a top view thereof, and Figure 1(c) is a side view thereof. Figure 2(a) is a front view of a side seal, and Figure 2(b) is a side view thereof. Figure 3(a) is a cross-sectional view of the sealing member, and Figure 3(b) is an enlarged view of part III of (a). Figure 4(a) is a top view of the underseal, Figure 4(b) is a front view thereof, Figure 4(c) is an enlarged cross-sectional view of the underseal along the line IV-IV in Figure 4(a), and Figure 4(d) is an enlarged cross-sectional view of the underseal along the line IV'-IV' in Figure 4(a). Figure 5 is an enlarged view showing the state from the free state of the sealing member, where the tops of the multiple ribs are located within the interference fit range, to the state in which the lip portion has an interference fit and slides against the opposing surface. Figure 6(a) is an enlarged view of the sealing member in its initial state before the first rib wears down, with the first rib sliding against the opposing surface. Figure 6(b) is an enlarged view of the sealing member after the first rib has worn down and the second rib is sliding against the opposing surface. Figure 6(c) is an enlarged view of the sealing member after the second rib has worn down and the third rib is sliding against the opposing surface. Figure 7(a) is an enlarged view of the sealing member after the third rib has worn down and the fourth rib is sliding against the opposing surface. Figure 7(b) is an enlarged view of the sealing member after all ribs have worn down and are in full contact with the opposing surface. Figure 8 is an enlarged view of the main part of the lip portion of the sealing member of the first modified example. Figure 9 is an enlarged view of the main part of the lip portion of the sealing member of the second modified example. Figure 10 is an enlarged view of the main part of the lip portion of the sealing member of the third modified example. Figure 11 is an enlarged view of the main part of the lip portion of the sealing member of the fourth modified example. Figure 12 is an enlarged view of the main part of the lip portion of the sealing member of the fifth modified example. Figure 13 is an enlarged view of the main part of the lip portion of the sealing member of the sixth modified example. Figure 14(a) is a cross-sectional view showing a sealing member of the seventh modified example, and Figure 14(b) is an enlarged view of its main part. Figure 15(a) is an enlarged view of the main part of a sealing member of the eighth modified example, and Figure 15(b) is an enlarged view of a sealing member in which the first and second ribs are in sliding contact with opposing surfaces. Figure 16 is an enlarged view of a sealing member in which the first and second ribs of the sealing member of Figure 15 have worn away and the third and fourth ribs are in sliding contact with opposing surfaces. Figure 17 is an enlarged cross-sectional view of the main part at the axial end of a slider according to a modified example of the slider of the above embodiment. Figure 18 is an enlarged cross-sectional view of the main part at the axial end of a slider according to another modified example of the slider of the above embodiment.Figure 19 is an enlarged cross-sectional view of a key part at the axial end of a slider, relating to yet another modification of the slider of the above embodiment. Figure 20(a) is a front view of a side seal of a linear guide using balls as rolling elements, Figure 20(b) is a cross-sectional view thereof, and Figure 20(c) is an enlarged view of part XX of (a) showing the seal member. Figure 21(a) is a cross-sectional view of a linear ball bearing incorporating the seal member, Figure 21(b) is a side view thereof, and Figure 21(c) is an enlarged view of part XXI of (a) showing the seal member.

[0013] Hereinafter, each embodiment of the sealing member according to the present invention will be described in detail with reference to the drawings. In the following description, the case in which the sealing member according to one embodiment of the present invention is applied to the side seal and under seal of a linear guide will be described as an example. In this specification, "textured structure" means a structure having irregularities.

[0014] As shown in Figure 1, the linear guide 1 comprises a guide rail 10 extending in one direction and a slider 20 with a C-shaped cross-section that straddles the guide rail 10 so as to be axially movable relative to it. In this embodiment, the axial direction refers to the longitudinal direction of the guide rail and is referred to as the X direction, and the left-right direction refers to the width direction of the slider 20 attached to the guide rail 10 and is referred to as the Y direction. Furthermore, the up-down direction is the direction perpendicular to the axial and left-right directions and is referred to as the Z direction.

[0015] The guide rail 10 is made of metal, and on its left and right sides, rail-side track surfaces 11 are formed in two vertical lines, both vertically and horizontally, along the axial direction of the guide rail 10. The top surface and left and right sides of the guide rail 10 are opposing surfaces 12, which are the surfaces that the sealing member 50, described later, slides against.

[0016] The slider 20 comprises a slider body 22 having sleeves on both the left and right sides of the guide rail 10, and a pair of end caps 30, 30 attached to both ends of the slider body 22 in the direction of movement. The end caps 30 are, for example, injection-molded products of synthetic resin material and are formed in a C-shape in cross-section, similar to the slider body 22. A set of return guides (not shown) are incorporated inside each of the end caps 30, 30.

[0017] Furthermore, a pair of side seals 40, 40 are positioned on the end face of the slider 20 (end cap 30) in the direction of movement. In addition, an underseal 35 is fixed to the lower surface of the sleeve portion of the slider 20.

[0018] Multiple rolling elements (rollers), not shown, are rotatably filled inside the slider 20, in the rolling element path formed between the slider 20 and the rail-side track surface 11 of the guide rail 10, and in the direction change path (not shown) formed between the end cap 30 and the return guide. The rolling of these rolling elements allows the slider 20 to move relative to the guide rail 10 in the axial direction. These multiple rolling elements then circulate indefinitely, rolling within the rolling element path and the direction change path as the guide rail 10 and the slider 20 move relative to each other.

[0019] The side seal 40 and under seal 35 fill the gap between the guide rail 10 and the slider 20, preventing foreign matter such as dirt, dust, and debris from entering the inside of the slider 20.

[0020] As shown in Figure 2, the side seal 40 is formed in a C-shape in plan view, similar to the cross-sectional shape of the slider body 22, and includes a sealing member 50 that slides against the guide rail 10, and a sealing case 41 and a sealing cover 42 that sandwich the sealing member 50.

[0021] The sealing member 50 is assembled by inserting the fitting projection 41a of the sealing case 41 into the fitting recess 50a of the sealing member 50, and then covering the side of the sealing case 41 with the sealing cover 42.

[0022] As shown in Figure 3, the sealing member 50 is made of an elastomer such as polyester elastomer, or an elastic material such as fluororubber or nitrile rubber. The sealing member 50 has a shape (C-shape) that conforms to the shape of both sides and the top surface which are the opposing surfaces 12 of the guide rail 10, and includes a main body portion 51 which is attached to the sealing case 41 and has a fitting recess 50a, and a lip portion 52 which extends diagonally from the inner end of the main body portion 51 toward the opposing surface 12 in the direction of movement of the slider 20 and slides in contact with the opposing surface 12 with an overlap.

[0023] The tip of the surface 53 on the opposing side of the lip portion 52 has a textured structure in which a plurality of ribs 55 (four in this embodiment) (first rib 55a to fourth rib 55d from the root side of the lip portion 52) are arranged in the direction of movement of the slider 20 (X direction), extending in a direction perpendicular to the direction of movement of the slider 20 (i.e., the Y direction when the opposing surface 12 is the top surface, and the Z direction when the opposing surface 12 is the side surface). In other words, the textured structure is composed of a plurality of ribs 55 that are arranged in a continuous line in the direction perpendicular to the seal contour direction (i.e., the Y direction when the opposing surface 12 is the top surface, and the Z direction when the opposing surface 12 is the side surface), in the direction of the seal contour direction (X direction), which is the direction that separates the gap sealed by the seal member 50 into the inside and the outside.

[0024] Each rib 55 has a substantially V-shaped cross-section with a pair of inclined surfaces that extend inclined toward both sides of the slider 20's direction of movement from its innermost top when viewed from a direction perpendicular to the slider 20's direction of movement. Furthermore, as shown in Figure 5, the top of each rib 55 is located within the range of the overlap D in the free state before the sealing member 50 is assembled to the slider 20 and then to the guide rail 10, that is, between the extension line 12A of the opposing surface 12 and a virtual surface 54 that is parallel to the opposing surface 12 and passes through the top of the rib 55, which is the innermost part in the Z direction.

[0025] In particular, in this embodiment, the first to third ribs 55a to 55c have substantially equal V-shaped cross-sections, and the fourth rib 55d has the same slope as the first to third ribs 55a to 55c on the slope behind the top of the substantially V-shaped cross-section (the slope on the right in Figure 3), while the slope in front of the top (the slope on the left in Figure 3) is formed by the tip surface 58 of the lip portion 52. Furthermore, the slope behind the top of the first rib 55a is formed in a straight line that is continuous with the surface 53 on the opposite side of the lip portion 52.

[0026] Furthermore, in this embodiment, the first ribs 55a to the fourth ribs 55d are formed such that the virtual surface 54 is parallel to the opposing surface 12 in the free state before the sealing member 50 described above is assembled to the slider 20 and then to the guide rail 10. In this case, the tops of the first ribs 55a to the fourth ribs 55d are located on the planar virtual surface 54.

[0027] Furthermore, the rib 55 optimizes the maximum contact pressure by optimizing the shape of its top surface, such as by creating a curved shape.

[0028] Furthermore, between adjacent ribs 55a to 55d, a relief groove 56 with a depth n is formed in a roughly U-shape by a bottom surface and a pair of parallel wall surfaces connecting the bottom surface and the slope of the rib. The relief groove 56 prevents full-surface contact when the rib 55 wears down, and the lubricant contained within the relief groove 56 prevents an abnormal increase in friction. It is desirable that the depth n of the relief groove 56 be 1 / 2 or less of the height H of the rib 55.

[0029] As shown in Figure 4, the underseal 35 fixed to the lower surface of the left and right sleeves of the slider 20 has a sealing member 50B that slides against the guide rail 10 and a sealing cover 37 (see Figure 1) for attaching the sealing member 50B to the sleeves of the slider body 22.

[0030] The sealing member 50B for the underseal comprises a main body portion 51 extending along the longitudinal direction of the slider body 22 and a lip portion 52 extending along one end of the main body portion 51 in the Y direction. As shown in Figure 4(c), the lip portion 52 extends diagonally downward from one end of the main body portion 51 in the Y direction and slides against the opposing surface 12 with an overlap. The shape of the surface 53 on the opposing surface side of the lip portion 52 is the same as the shape of the lip portion 52 of the side seal 40. That is, the sealing member 50B of this embodiment also has a textured structure in which the lip portion 52 has a plurality of ribs 55, and its function is the same as that of the sealing member 50.

[0031] Furthermore, as shown in Figure 4(d), both longitudinal ends of the sealing member 50B for the underseal are located in approximately the same position as the X-direction position of each side seal 40, and auxiliary sealing portions 60 for filling the gap formed at the joint between the underseal 35 and the side seal 40 are integrally provided at both longitudinal ends of the sealing member 50B. Note that the auxiliary sealing portions for filling the gap formed at the joint between the underseal and the side seal may be integrally provided at the left and right ends (lower ends) of the side seals.

[0032] Next, the operation of the sealing member 50 of the side seal 40 will be explained. As shown in Figure 5, the sealing member 50 is assembled from the chamfered end face side of the guide rail 10. In the free state, a virtual surface 54 is defined as a surface parallel to the opposing surface 12 that passes through the top of the innermost rib 55 (55a to 55d). If the distance from the end face corner of the chamfered portion 13 to the virtual surface 54 is X, the angle between the tip surface 58 of the sealing member 50 and the virtual surface 54 is L°, and the chamfer angle is R°, then it is desirable that X > 0 and R < L in order to smoothly assemble the sealing member 50 to the guide rail 10 (opposing surface 12). The distance between the opposing surface 12 and the virtual surface 54 is the overlap D. In this invention, the virtual surface 54 that provides the overlap D is provided as a surface that passes over the top of the innermost rib 55 (lower side in Figure 5) in the Z-axis direction among the at least one rib 55 that contacts the opposing surface 12 in the initial state before the rib 55 wears down, and is provided as a surface that follows the seal contour direction, which is the direction that divides the gap sealed by the seal member 50 into the inside A and the outside B.

[0033] As shown in Figure 6(a), when the sealing member 50 having an overlap D with respect to the opposing surface 12 is assembled to the guide rail 10, the lip portion 52 is pressed against the opposing surface 12 and deforms mainly in a direction inclined towards the root side (clockwise in the figure). Then, the first rib 55a, which is the closest to the root among the multiple ribs 55, comes into contact with the opposing surface 12, while the second ribs 55b to the fourth ribs 55d, which are further forward than the first rib 55a, move away from the opposing surface 12, creating a gap between them and the opposing surface 12. This is the initial state before the first to fourth ribs 55a to 55d wear down.

[0034] In this initial state, only the first rib 55a is in contact with the opposing surface 12, while the remaining second ribs 55b to fourth ribs 55d are spaced apart from the opposing surface 12. Therefore, in the absence of foreign matter, it can be used in the same way as a typical ribless lip seal. In this state, the first rib 55a can secure a sufficient maximum contact pressure and contact pressure gradient, thereby achieving high sealing performance.

[0035] As the linear guide 1 is used, the first rib 55a that slides against the opposing surface 12 wears down, and as the rib wear progresses, the contact area increases, the maximum contact pressure and the gradient of the contact pressure decrease, and the sealing performance deteriorates.

[0036] However, as shown in Figure 6(b), the elastic force of the lip portion 52 causes the lip portion 52 to lower by the amount of wear, and the next second rib 55b adjacent to the first rib 55a comes into contact with the opposing surface 12. When the second rib 55b comes into contact with the opposing surface 12, the first rib 55a also comes into contact with the opposing surface 12, but at a predetermined overlap D, the contact area of ​​the second rib 55b is smaller than the contact area of ​​the first rib 55a, so the surface pressure of the second rib 55b is higher than the surface pressure of the first rib 55a. As a result, the maximum surface pressure necessary to scrape off foreign matter is restored, and good sealing performance is achieved. From the initial contact of the second rib 55b until it wears down to a certain extent (until the contact area with the first rib 55a due to the overlap D is equal), it exhibits a higher contact surface pressure and contact surface pressure gradient than the worn first rib 55a, so even if the first rib 55a is worn down, high sealing performance can still be obtained.

[0037] Furthermore, as the second rib 55b wears down due to the left-right movement of the slider 20, the next third rib 55c comes into contact with the opposing surface 12 (see Figure 6(c)). Also, when the third rib 55c makes contact, the first rib 55a and the second rib 55b also come into contact with the opposing surface 12, but at a predetermined overlap D, the relationship is (surface pressure of the third rib 55c > surface pressure of the second rib 55b > surface pressure of the first rib 55a). As a result, the maximum surface pressure necessary to scrape off foreign matter is restored, and good sealing performance is achieved. From the initial contact of the third rib 55c until it wears down to a certain extent (until the contact area with the first and second ribs 55a and 55b is equivalent due to the overlap D), it exhibits a higher contact surface pressure and contact surface pressure gradient than the worn first and second ribs 55a and 55b, so even if the first and second ribs 55a and 55b wear down, high sealing performance can still be obtained.

[0038] Similarly, as the third rib 55c wears down, the fourth rib 55d comes into contact with the opposing surface 12 (see Figure 7(a)), and as the fourth rib 55d wears down, the worn portions of the first rib 55a to the fourth rib 55d come into full contact with the opposing surface 12 (see Figure 7(b)). Therefore, high sealing performance can be obtained until the fourth rib 55d wears down to a certain extent.

[0039] As described above, in the sealing member of the present invention, when one rib 55 wears down, the next unworn rib 55 sequentially comes into contact with the opposing surface 12. This allows for the maintenance of a maximum contact pressure and a gradient of contact pressure necessary and sufficient to sweep away foreign matter and liquids over a long period of time, thereby extending the lifespan of the sealing member 50.

[0040] Furthermore, the maximum contact pressure when the rib 55 contacts the opposing surface 12, and the pressure gradient viewed from the direction of slider movement, are set to values ​​that are sufficient to scrape off foreign matter and liquids expected in the operating environment of the linear guide.

[0041] The shape of the sealing member may be modified as appropriate, as shown in the first to eighth modified examples below.

[0042] (Sealing member of the first modified example) The sealing member 50 may have a chamfered top of the fourth rib 55d, which is closer to the tip of the lip portion 52, as shown in the first modified example in Figure 8. That is, the top of the fourth rib 55d may be located away from the virtual plane 54 connecting the tops of the first to third ribs 55a to 55c in the free state. In other words, in the free state of the sealing member 50, the surface 53 of the lip portion 52 facing the opposing surface 12 has a textured structure in which multiple ribs 55 are arranged in a continuous line in the direction of the seal contour. Also, in the free state of the sealing member 50, the top of each rib 55 is located within the range of the overlap D. In this case as well, when the third rib 55c is worn down, the fourth rib 55d comes into contact with the opposing surface 12, and high sealing performance can be maintained over a long period of time, similar to the above embodiment.

[0043] (Sealing member of the second modification example) Further, as in the second modification example shown in FIG. 9, in the sealing member 50, when the angle of the front slope 55f of the V-shaped first to fourth ribs 55a to 55d with respect to the virtual surface 54 is T° and the angle of the rear slope 55g with respect to the virtual surface 54 is M°, T > M. As a result, the oil film thickness when moving leftward in the figure < the oil film thickness when moving rightward, preventing foreign matter from entering from the outside, while supplying the internal lubricant to the contact surface of the lip portion 52, and delaying the progress of wear.

[0044] (Sealing member of the third modification example) Further, as in the third modification example shown in FIG. 10, in the sealing member 50, the root side thickness W1 of the lip portion 52 > the tip side thickness W2, and the lip portion 52 is formed in a tapered shape that tapers. That is, when the angle of the surface 53 on the facing surface side of the lip portion 52 with respect to the virtual surface 54 is α° and the angle of the surface 57 on the non-facing surface side of the lip portion 52 with respect to the virtual surface 54 is γ°, it is preferable that α < γ. Furthermore, it is desirable that the angle γ satisfies α < γ < α + 10°. By forming the lip portion 52 in a tapered shape in this way, when the rib 55 wears, the lip portion 52 is easily deformed, and the lip portion 52 can easily follow the facing surface 12.

[0045] However, the distance Y between the intersection point when the surface 57 on the non-facing surface side of the lip portion 52 is extended to the tip of the lip portion 52 and the top of the rib 55 at the tip of the lip portion 52 is preferably Y > 0. Also, on the tip side of the lip portion 52, the surface 57 on the non-facing surface side may be formed to be parallel to the virtual surface 54.

[0046] (Sealing member of the fourth modification example) Also, in the sealing member 50 of the fourth modification example shown in FIG. 11, in the free state, the surface 53 of the lip portion 52 facing the facing surface 12 has two surfaces, a root side surface 53a and a tip side surface 53b, with different angles, between the root side of the lip portion 52 and the most root side rib (first rib) 55a. The angle of the root side surface 53a with respect to the virtual surface 54 is 15° to 30°, the angle of the tip side surface 53b with respect to the virtual surface 5 is 5° to 13°, and the boundary between the tip side surface 53b and the root side surface 53a is smoothly connected by a curve.

[0047] If the lip contact position at the stroke end changes, there is a risk of seal leakage and intrusion of minute external foreign matters at the stroke end. However, by adjusting the angle between the base side surface 53a and the tip side surface 53b, the contact area can be adjusted to optimize the contact surface pressure. Also, by smoothly connecting the tip side surface 53b and the base side surface 53a with a curve, even if the contact position fluctuates, lubricant can be surely supplied to the lip contact surface while minimizing the passage of foreign matters.

[0048] Further, the inclined surfaces 55f in front of the first to third ribs 55a to 55c are formed as continuous vertical surfaces from the wall surface perpendicular to the moving direction of the slider 20 of the relief groove 56, and the top shapes of the first to fourth ribs 55a to 55d are formed in an arc shape. Therefore, the first to third ribs 55a to 55c are formed in a substantially V-shaped cross section asymmetric in the X direction.

[0049] As a result, when each rib 55 comes into contact, a difference occurs between the surface pressure gradient on the outer side (left side) and the surface pressure gradient on the inner side (right side) of the contact surface of the lip portion 52. The surface pressure gradient is higher on the left side of the contact surface of the lip portion 52 and lower on the right side. Thereby, the oil film thickness formed when the lip portion 52 moves leftward becomes thinner, and the oil film thickness formed when the lip portion 52 moves rightward becomes thicker than the former. When moving leftward, it can prevent the intrusion of extremely fine foreign matters from the outside, and when moving rightward, by appropriately leaving the lubricant inside the slider on the rail surface, it can prevent the intrusion of foreign matters into the slider while preventing lip wear and extending the life of the linear guide.

[0050] (Fifth Modified Seal Member) In the fifth modified seal member 50 shown in Figure 12, the first rib 55a is formed to protrude downward from the surface 53 of the lip portion 52 in the free state. The roughly V-shaped first to fourth ribs 55a to 55d each have a first inclined surface 56a near the top with a small angle with respect to the virtual surface 54, and a second inclined surface 56b near the bottom of the relief groove 56 with a larger angle with respect to the virtual surface 54 than the first inclined surface 56a. Therefore, the relief groove 56 is formed such that its width in the X direction widens as it goes downward from the bottom surface by the second inclined surface 56b. Also, the second inclined surface 56b of the first rib 55a intersects with the surface 53 of the lip portion 52. Even in such a lip portion 52, by adjusting the shapes of the first to fourth ribs 55a to 55d, it is possible to obtain a sufficient maximum contact pressure and a gradient of contact pressure over a long period of time in the first to fourth ribs 55a to 55d.

[0051] (Sixth modified sealing member) In the sixth modified sealing member 50 shown in Figure 13, the top shape of each rib 55, which has a substantially V-shaped cross-section, is formed in an arc shape, and the surface 53 on the opposing side of the lip portion 52 is formed as a curved surface. By making the surface 53 on the opposing side a curved surface, when the rib 55 wears down, the lip portion 52 deforms continuously and smoothly, and the lip portion 52 reliably follows the opposing surface 12.

[0052] (Sealing member of the seventh modified example) In the sealing member 50 of the seventh modified example shown in Figure 14, in the free state, the tops are formed in a stepped manner such that the position in the Z direction in the figure is gradually upward from the first rib 55a to the fourth rib 55d. Therefore, in the free state, the second rib 55b to the fourth rib 55d gradually move away from the virtual surface 54 that passes over the top of the first rib 55a along the axial direction of the sealing member 50.

[0053] However, even in this case, the tops of the multiple ribs 55a to 55d are located within the overlap D range and are arranged continuously in the direction of the seal contour (in this embodiment, the axial direction of the seal member 50).

[0054] By configuring multiple ribs 55a to 55d in this manner, the rib that contacts the opposing surface 12 will wear down, and the distance traveled before the next rib 55 makes contact can be extended.

[0055] (Sealing member of the eighth modified example) The sealing member 50 of the eighth modified example shown in Figure 15 has a lip portion 52 that abuts with the opposing surface 12 with an overlap D, and in the initial state before the ribs 55 wear down, two first and second ribs 55a and 55b from the root side of the lip portion 52 abut the opposing surface 12, while the remaining third and fourth ribs 55c and 55d are spaced apart from the opposing surface 12, that is, it constitutes a double lip in which the two ribs 55a and 55b slide in contact.

[0056] Therefore, in the free state of the sealing member 50, the first and second ribs 55a and 55b, which are the two ribs from the root side of the lip portion 52, are positioned so that they contact the opposing surface 12, with the second rib 55b, which is closer to the tip, being closer to the opposing surface 12 than the first rib 55a, which is closer to the root side. Similarly, the third and fourth ribs 55c and 55d are positioned so that they contact the opposing surface 12, with the fourth rib 55d, which is closer to the tip, being closer to the opposing surface 12 than the third rib 55c, which is closer to the root side.

[0057] When the first and second ribs 55a and 55b wear down, the third and fourth ribs 55c and 55d come into contact with the opposing surface 12, as shown in Figure 16, and maintain the sealing performance.

[0058] With this configuration, even if damage or defects occur to one of the first and second ribs 55a, 55b (or the third and fourth ribs 55c, 55d) due to foreign matter, the other rib can maintain sealing performance, preventing damage to the linear guide until the rib wears out due to abrasion.

[0059] Thus, in the present invention, in the initial state before the ribs 55 wear down, multiple rows of ribs 55 from the root side of the lip portion 52 simultaneously contact the opposing surface 12. In the free state of the sealing member 50, the ribs 55 on the tip side are closer to the opposing surface 12 than the ribs 55 on the root side.

[0060] Furthermore, as shown in Figure 17, a lubricant unit 33 may be provided between the end cap 30 and the side seal 40, in which a solid lubricant (for example, a porous material such as rubber or synthetic resin impregnated with lubricant, or a fiber entanglement) 31 is housed in a lubricant case 32. The solid lubricant 31 is effective in improving the lubrication performance between the guide rail 10 and the slider 20.

[0061] Furthermore, as shown in Figure 18, two lubricant cases 32 containing sealing members 50 and solid lubricant may be arranged to the side of the end cap 30. The lip portions 52 of each sealing member 50 are arranged facing opposite directions. The sealing member 50 whose lip portion 52 extends in the direction of the slider body 22 (to the right in the figure) is for holding the lubricant. Alternatively, the lubricant cases 32 may be placed outside the sealing members 50 (to the left in the figure) for seal protection.

[0062] Furthermore, although the linear guide shown in Figure 18 is a double seal having two sealing members 50, as shown in Figure 19, it may also be a single seal having a sealing member 50 with a lip portion 52 extending in the direction of the slider body 22 (to the right in the figure). In this case, when the second rib 55b comes into sliding contact with the first rib 55a due to wear of the first rib 55a, the foreign matter that is separated from the relief groove 56 is discharged to the outside (to the left in the figure), eliminating concerns about it entering the inside of the slider. In addition, in the double seal shown in Figure 18, the left sealing member 50 with a lip portion 52 extending outward (to the left in the figure) can remove large or sticky foreign matter, and the right sealing member 50 with a lip portion 52 extending in the direction of the slider body 22 (to the right in the figure) also has the effect of preventing foreign matter that is caught in the relief groove 56 from entering.

[0063] Furthermore, although the above embodiment shows the case in which the sealing member 50 of the present invention is used in a linear guide having rollers as rolling elements, it is also applicable to linear guides having balls as rolling elements. Figure 20 shows a side seal 40 applied to a linear guide having balls, in which case the main body portion 51 of the sealing member 50C has a shape that fits into the seal case 41, and a seal cover is not required. Also, the lip portion 52 of the sealing member 50C has a texture structure consisting of a plurality of ribs 55 that are provided at the tip of the surface 53 on the opposite side of the lip portion 52 and extend in a direction perpendicular to the direction of movement of the slider 20, and can operate in the same way as in the above embodiment.

[0064] Furthermore, the present invention is not limited to the embodiments described above, and can be modified, improved, etc., as appropriate. Although the above embodiments described a linear guide, the sealing member of the present invention can be applied as other reciprocating seals, such as linear ball bearings, reciprocating lip seals for ball screws, reciprocating lip seals for ball splines, and reciprocating lip seals for steering intermediate shafts.

[0065] For example, Figure 21 shows an example in which the sealing member of the present invention is applied to a linear ball bearing. The linear ball bearing 3 comprises a shaft (not shown), a nut 61, and a plurality of balls 62. The sealing member 50D is formed in an annular shape and is secured in a seal mounting recess 63 provided at the moving end of the nut 61.

[0066] The sealing member 50D of this embodiment also comprises a main body portion 51 having a core metal 59, a lip portion 52 extending diagonally from the main body portion 51 toward the opposing surface 12 in the direction of movement, and a plurality of ribs 55 provided at the tip of the surface 53 on the opposing surface side of the lip portion 52, extending in a direction perpendicular to the direction of movement of the nut 61, and is formed in a substantially circular disc shape. The virtual surface 54 of this embodiment is formed in a substantially cylindrical shape that follows the cross-sectional shape of a screw shaft cut perpendicular to the central axis. In this case as well, the configuration and operation of the sealing member 50D are basically the same as those of the sealing member 50 of the above embodiment.

[0067] Furthermore, the sealing member of the present invention is not limited to reciprocating seals, but can also be applied to rotating seals such as bearings.

[0068] Furthermore, in all of the above embodiments, the tops of the multiple ribs 55 and the relief grooves 56 between the multiple ribs 55 are located within the range of the overlap D when the sealing member 50 is in a free state. However, in the sealing member of the present invention, it is sufficient that at least the tops of the multiple ribs 55 are located within the range of the overlap D when the sealing member 50 is in a free state, and at least one relief groove 56 may be outside the range of the overlap D when the sealing member 50 is in a free state.

[0069] As described above, the following matters are disclosed in this specification: (1) A sealing member attached to a moving member so as to close a gap between a fixed member and a moving member that moves relative to the fixed member, and sliding in contact with an opposing surface provided on the fixed member, comprising: a main body portion and an elastic lip portion extending diagonally from the main body portion toward the opposing surface and sliding in contact with the opposing surface with an overlap, wherein the surface of the lip portion facing the opposing surface has a textured structure in which a plurality of ribs are arranged in a continuous line in a direction perpendicular to the seal contour direction, which is the direction in which the gap that the sealing member closes is divided into an interior and an exterior, and the tops of the plurality of ribs are located within the overlap range in the free state of the sealing member. With this configuration, multiple ribs whose tops are located within the overlap range are arranged continuously in the direction of the seal contour, resulting in boundary lubrication. Even if the maximum contact pressure and the gradient of the contact pressure decrease as lip wear progresses and sealing performance deteriorates, the adjacent unworn ribs slide against the opposing surface, ensuring that sufficient maximum contact pressure and a sufficient gradient of the contact pressure are maintained over a long period to sweep away foreign matter and liquids.

[0070] (2) The sealing member according to (1), wherein the lip portion abuts the opposing surface with an overlap, and in the initial state before the ribs wear, at least one rib from the root side of the lip portion abuts the opposing surface, and the remaining ribs are spaced apart from the opposing surface. With this configuration, in the initial state, at least one rib from the root side of the lip portion abuts the opposing surface, making it possible to obtain a maximum contact pressure and a gradient of contact pressure necessary and sufficient to sweep away foreign matter and foreign liquids. Furthermore, even if the maximum contact pressure and the gradient of contact pressure decrease and the sealing performance deteriorates as the rib wear of the lip portion progresses, the adjacent unworn rib abuts the opposing surface, making it possible to obtain a maximum contact pressure and a gradient of contact pressure necessary and sufficient to sweep away foreign matter and foreign liquids over a long period of time. Therefore, the lifespan of the sealing member can be extended.

[0071] (3) The sealing member according to (1), wherein the lip portion abuts the opposing surface with an overlap, and in the initial state before the ribs wear, the rib closest to the root of the lip portion abuts the opposing surface, and the remaining ribs are spaced apart from the opposing surface. With this configuration, in the initial state, the rib closest to the root abuts the opposing surface, so that a maximum contact pressure and a gradient of contact pressure necessary and sufficient to sweep away foreign matter and foreign liquid can be obtained. Furthermore, even if the maximum contact pressure and the gradient of contact pressure decrease and the sealing performance deteriorates as the rib wear of the lip portion progresses, the adjacent unworn rib abuts the opposing surface, so that a maximum contact pressure and a gradient of contact pressure necessary and sufficient to sweep away foreign matter and foreign liquid can be obtained for a long period of time. Therefore, the life of the sealing member can be extended.

[0072] (4) The sealing member according to any one of (1) to (3), wherein each of the plurality of ribs has a substantially V-shaped cross section with a pair of inclined surfaces extending from the top toward both sides in the direction of movement of the moving member. With this configuration, a maximum contact pressure and a gradient of contact pressure necessary and sufficient to sweep away foreign matter and foreign liquid can be obtained over a long period of time, and good sealing performance can be maintained over a long period of time.

[0073] (5) The surface of the lip portion facing the opposing surface comprises a root side surface between the root side of the lip portion and the rib at the very root, with an angle of 15° to 30° with respect to the opposing surface, and a tip side surface with an angle of 5° to 13° with respect to the opposing surface, and the tip side surface and the root side surface are smoothly connected by a curve, as described in (4). With this configuration, it is possible to supply lubricant when the contact portion fluctuates while minimizing the passage of foreign matter.

[0074] (6) A sealing member according to any one of (1) to (5), wherein relief grooves are formed between each of the plurality of ribs. With this configuration, an abnormal increase in wear can be prevented by the lubricant secured in the relief grooves.

[0075] (7) A sealing member according to any one of (1) to (6), applicable to linear guides, ball screws, splines, bearings, and intermediate shafts. This configuration effectively seals the gap between the moving member and the stationary member of the linear guide, ball screw, spline, and intermediate shaft.

[0076] (8) The sealing member described in (7), wherein the sealing member is used as an underseal of the linear guide, and auxiliary sealing portions are integrally provided at both longitudinal ends of the underseal to fill the gap formed at the joint between the underseal and the side seal. This makes it possible to fill the gap formed at the joint between the underseal and the side seal, thereby improving the sealing performance of the linear guide.

[0077] This application is based on the Japanese Patent Application No. 2025-27265 filed on February 21, 2025, the contents of which are incorporated by reference within this application.

[0078] D Tightening allowance 10 Guide rail (fixing member) 12 Opposing surface 20 Slider (moving member) 50, 50B, 50C, 50D Seal member 51 Main body 52 Lip 53 Opposing surface side 53a Base side 53b Tip side 54 Virtual surface (surface connecting the lowest points of each rib) 55, 55a, 55b, 55c, 55d Rib

Claims

1. A sealing member that is attached to a moving member so as to close the gap between the fixed member and the moving member that moves relative to the fixed member, and that slides against an opposing surface provided on the fixed member, comprising: a main body portion and an elastic lip portion that extends diagonally from the main body portion toward the opposing surface and slides against the opposing surface with an overlap, wherein the surface of the lip portion facing the opposing surface has a textured structure in which a plurality of ribs are continuously arranged in a direction perpendicular to the seal contour direction, which is the direction in which the gap that the sealing member closes is divided into an interior and an exterior, and the tops of the plurality of ribs are located within the overlap range when the sealing member is in a free state.

2. The sealing member according to claim 1, wherein the lip portion abuts the opposing surface with an overlap, and in the initial state before the ribs wear, at least one rib abuts the opposing surface from the root side of the lip portion, and the remaining ribs are spaced apart from the opposing surface.

3. The sealing member according to claim 2, wherein the lip portion abuts the opposing surface with an overlap, and in the initial state before the rib wears down, the rib closest to the root of the lip portion abuts the opposing surface, and the remaining rib is spaced apart from the opposing surface.

4. The sealing member according to claim 1, wherein each of the plurality of ribs has a substantially V-shaped cross-section with a pair of inclined surfaces extending from the top toward both sides in the direction of movement of the movable member.

5. The sealing member according to claim 4, wherein the surface of the lip portion facing the opposing surface comprises a root side surface having an angle of 15° to 30° with respect to the opposing surface and a tip side surface having an angle of 5° to 13° with respect to the opposing surface, between the root side of the lip portion and the rib at the most root side, and the tip side surface and the root side surface are smoothly connected by a curve.

6. The sealing member according to claim 1, wherein relief grooves are formed between each of the plurality of ribs.

7. A sealing member according to any one of claims 1 to 6, applicable to linear guides, ball screws, splines, bearings, and intermediate shafts.

8. The sealing member according to claim 7, wherein the sealing member is used as an underseal of the linear guide, and auxiliary sealing portions are integrally provided at both longitudinal ends of the underseal to fill the gap formed at the joint between the underseal and the side seal.

Images