Seal member

Abstract

To facilitate a mount work of a screw shaft on an intermediate part in an axial direction in a seal member used in a screw device.SOLUTION: In a ball screw device 10 having a screw shaft 20 and a nut 30, a seal member 40 is a seal member disposed in an approximately annular space A between the screw shaft 20 and the nut 30, includes an annular core material 50, and a pile material 60 covering at least an inner peripheral surface 51 and an axial end surface 52 of the core material 50, and has a slit part 46 made by discontinuing the seal member in a circumferential direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a sealing member technology. [Background technology]

[0002] A screw device is known as a mechanical element that converts the rotational motion of a motor or the like into linear motion. The screw device includes a screw shaft having a helical groove on the outer circumference and a nut having a helical groove on the inner circumference. A ball screw device, which is an example of the screw device, further includes a plurality of balls that roll between the screw shaft and the nut. If foreign matter enters the inside of the screw device, the screw device may be deteriorated, such as a decrease in the feed accuracy of the screw device or an increase in the torque required for rotation. For this reason, the screw device includes a seal member for suppressing the intrusion of foreign matter between the screw shaft and the nut. Such a seal member deteriorates with use and therefore requires periodic replacement. Conventionally, a seal member having a two-part structure for easy replacement has been disclosed (see Patent Document 1).

[0003] The seal member can be attached to the axial middle of the screw shaft by combining the two seal members while the screw shaft is disposed between them (diametrically inward). The seal member can be removed from the screw shaft by separating the seal member into two members while the seal member is located at the axial middle of the screw shaft. For this reason, in a screw device using the seal member, it is possible to replace the seal member without extensive disassembly to expose the axial end of the screw shaft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 08-145143 Summary of the Invention [Problem to be solved by the invention]

[0005] In the operation of mounting the seal member on the screw shaft, the worker needs to hold one of the two divided seal members with one hand and hold the other with the other hand to mount the seal member on the screw shaft. In other words, the worker needs to use both hands to mount the seal member on the screw shaft. For this reason, when there is only a narrow space around the screw shaft that is small enough to fit only one hand, it is difficult to mount the seal member on the axial middle part of the screw shaft.

[0006] An object of the present disclosure is to facilitate the attachment operation of a sealing member used in a screw device to an axial middle portion of a screw shaft. [Means for solving the problem]

[0007] The sealing member disclosed herein is a sealing member that is arranged in an approximately annular space between a screw shaft and a nut in a screw device having the screw shaft and a nut, and includes a circular core material and a sheet-like pile material that covers at least the inner surface and the axial end face of the core material, and has a slit portion that is discontinuous midway in the circumferential direction. Effect of the Invention

[0008] According to the present disclosure, it is possible to facilitate the attachment operation of a seal member used in a screw device to an axially intermediate portion of a screw shaft. [Brief description of the drawings]

[0009] [Figure 1] FIG. 4 is an enlarged perspective view showing an arrangement of a seal member in the screw device. [Diagram 2] FIG. 4 is an enlarged perspective view showing a fixing state of a seal member in a screw device. [Diagram 3] 4 is a cross-sectional view showing the arrangement of a seal member in a screw device. FIG. [Figure 4] FIG. 2 is a perspective view showing a sealing member according to the first embodiment. [Diagram 5] FIG. 2 is a cross-sectional view showing the seal member according to the first embodiment. [Figure 6] FIG. 2 is a perspective view showing a core material constituting the sealing member according to the first embodiment. [Figure 7A] FIG. 4 is a side view showing the shape of a groove in the core material. [Figure 7B] FIG. 13 is a side view showing an embodiment of a groove having a restricting portion. [Figure 7C] 13 is a side view showing another embodiment of a groove having a restricting portion. FIG. [Figure 8] FIG. 11 is a side view showing a sealing member according to a second embodiment (with a slit portion closed). [Figure 9] FIG. 11 is a side view showing the sealing member according to the second embodiment (with the slit portion open). [Figure 10] FIG. 11 is a side view showing a core material constituting a sealing member according to a second embodiment. [Figure 11] FIG. 11 is a perspective view showing a state in which an auxiliary seal member is attached in the seal member according to the second embodiment. [Figure 12] FIG. 11 is a perspective view showing a sealing member according to a third embodiment. [Figure 13] FIG. 11 is a perspective view showing a sealing member (divided state) according to a third embodiment. [Figure 14] FIG. 11 is a perspective view showing a core material constituting a sealing member according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Overview of the embodiment of the present disclosure> Below, an overview of the embodiments of the present disclosure will be listed and described. (1) The sealing member disclosed herein is a sealing member disposed in a substantially annular space between a screw shaft and a nut in a screw device having the screw shaft and a nut, the sealing member including a circular core material and a pile material covering at least an inner surface and an axial end face of the core material, and having a slit portion that is discontinuous midway in the circumferential direction.

[0011] The seal member having the above configuration allows a user to hold the seal member with one hand and open the slit portion. Therefore, the seal member having the above configuration can be attached to the middle portion of the screw shaft with one hand. The seal member having the above configuration makes it easy to attach the seal member used in the screw device to the middle portion of the screw shaft in the axial direction.

[0012] (2) The sealing member according to the embodiment of (1) further includes a fixing member for fixing the pile material to an axial end face of the core material, the core material having a pinhole formed in the axial end face, the fixing member having a needle-shaped portion to be inserted into the pinhole, and the needle-shaped portion being inserted into the pinhole while piercing the pile material. The sealing member of the above configuration can reliably fix the pile material to the core material by the fixing member. The sealing member of the above configuration can suppress peeling of the pile material from the core material with respect to the sealing member that can facilitate the installation work to the axial middle part of the screw shaft, thereby ensuring the sealing property of the sealing member.

[0013] (3) In the sealing member according to the embodiment (2), it is preferable that the slit portion has a first end face and a second end face that face each other in the circumferential direction, and the pile material further covers the first end face and the second end face. In the sealing member having such a configuration, the pile material can seal any gaps that may exist in the slit portion. This ensures the sealing performance of the sealing member having the slit portion.

[0014] (4) In the sealing member according to the embodiment (2) or (3), it is preferable that the sealing member further has a notch formed at a position facing the slit in the radial direction. The sealing member having such a configuration has the notch, which allows the slit to be opened wider. Therefore, the sealing member having the above configuration makes it easier to insert the screw shaft from the slit to the radial inside of the sealing member.

[0015] (5) It is preferable that the sealing member according to the embodiment (4) further includes an auxiliary sealing member that fills the cutout portion. The sealing member having such a configuration can seal the cutout portion with the auxiliary sealing member. This ensures the sealing performance of the sealing member having the cutout portion. (6) In the sealing member according to the embodiment (4) or (5), it is preferable that the pile material covering the inner peripheral surface of the core material is continuous in the circumferential direction at the cutout portion. With this configuration, the sealing member having the cutout portion can be configured as a single member that is not separated. Therefore, the sealing member having the above configuration can be easily attached to the middle portion of the screw shaft.

[0016] (7) In the sealing member according to any one of the embodiments (1) to (6), it is preferable that the core material has a groove portion formed on the outer circumferential surface over the entire circumferential area. With a sealing member having such a configuration, it is not necessary to form a hole portion for inserting a set screw every time the sealing member is replaced. Furthermore, with a sealing member having such a configuration, a set screw can be inserted into the groove portion regardless of the circumferential phase. Therefore, it is possible to improve the workability of the replacement work for a sealing member used in a screw device.

[0017] (8) In the seal member according to any one of the embodiments (1) to (7), the core preferably has a restricting portion at the bottom of the groove portion that restricts relative displacement between the core and a member that abuts against the bottom. With a seal member having such a configuration, the restricting portion can suppress phase shift in the circumferential direction of the seal member attached to the nut after attachment. This ensures stable sealing performance for the seal member.

[0018] <Details of the embodiment of the present disclosure> Hereinafter, the details of the embodiments of the present disclosure will be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any combination.

[0019] [Overall configuration of the screw device] FIG. 1 is an enlarged perspective view showing the arrangement of a seal member in a screw device. FIG. 2 is an enlarged perspective view showing the fixing state of a seal member in the screw device. FIG. 3 is a cross-sectional view showing the arrangement of a seal member in the screw device. In addition, an xyz orthogonal coordinate system is attached to FIG. 1 to FIG. 3 for the purpose of explaining the screw device. In the following explanation, the x-axis direction is referred to as the "axial direction", the positive side of the x-axis direction is referred to as the "one axial side", and the negative side of the x-axis direction is referred to as the "other axial side". In addition, the yz plane is a plane perpendicular to the axial direction.

[0020] 1 to 3 show a ball screw device 10, which is one embodiment of a screw device. The ball screw device 10 is an example of a screw device to which the seal member of the present disclosure is applied. As shown in FIGS. 1 to 3, the ball screw device 10 includes a screw shaft 20, a nut 30, and a seal member 40.

[0021] The ball screw device 10 is a device that converts the rotation of one of the screw shaft 20 and the nut 30 into the axial displacement of the other of the screw shaft 20 and the nut 30. One of the screw shaft 20 and the nut 30 is connected to a rotating mechanism (not shown) such as a motor and a pulley, and is rotated around a center line C by the rotating mechanism. As a result, the other of the screw shaft 20 and the nut 30 moves linearly in the axial direction. That is, the screw shaft 20 and the nut 30 rotate relatively around the center line C. Note that, in the present embodiment, the ball screw device 10 in which the nut 30 includes a ball 32a (see FIG. 3) is illustrated for explanation, but the screw device to which the seal member of the present disclosure is applied does not have to be a ball screw device, and may be a screw device that does not include a ball.

[0022] As shown in Figs. 1 to 3, the screw shaft 20 is an axial member whose axis is a center line C, and is provided so as to be rotatable around the center line C. A screw thread 21 is formed helically on an outer peripheral surface 20a of the screw shaft 20. A screw groove 22 is formed helically between two screw threads 21 adjacent to each other in the axial direction. The center line C is parallel to the x-axis direction (axial direction). In the following description, the direction perpendicular to the center line C is referred to as the "radial direction", and the direction around the center line C is referred to as the "circumferential direction".

[0023] 3, the nut 30 supports the screw shaft 20. The nut 30 includes a housing 31 and a nut portion 32.

[0024] The housing 31 is a substantially cylindrical member, and has a through hole 31a penetrating in the axial direction, and a seal case portion 31b that expands the diameter of the through hole 31a at one end in the axial direction. The seal case portion 31b is an annular recess formed coaxially with the through hole 31a, and accommodates the seal member 40. The seal case portion 31b has a step portion 31d at the other end in the axial direction. The seal member 40 accommodated in the seal case portion 31b has an outer peripheral surface 43 in contact with the inner peripheral surface 31f, and an end face 42 on the other axial side in contact with the step portion 31d.

[0025] The nut portion 32 is a portion that functions as a nut that screws onto the screw shaft 20 (the thread 21 and the thread groove 22), and is formed on the other axial side of the housing 31. The case portion 32b is a substantially cylindrical portion that protrudes radially inward from the inner peripheral surface of the through hole 31a. The nut portion 32 includes a plurality of balls 32a and a case portion 32b that houses the plurality of balls 32a. A screw groove 32c that holds the balls 32a between the screw groove 22 and the inner peripheral surface of the case portion 32b is formed in a spiral shape. A passage 32d that communicates between one end of the screw groove 32c in the axial direction and the other end of the screw groove 32c in the axial direction is formed inside the case portion 32b. The balls 32a circulate in a series of closed paths formed by the screw groove 32c and the passage 32d.

[0026] The housing 31 further has a flange portion 33. The flange portion 33 is a portion extending radially outward from one axial end of the housing 31. The flange portion 33 is used as a portion for fixing the nut 30 to a device (not shown). The seal case portion 31b is located radially inward of the flange portion 33.

[0027] The housing 31 further has a through hole 34. The through hole 34 is a hole for passing a set screw 35, and penetrates radially from the radial outside of the flange portion 33 to the seal case portion 31b. The through hole 34 has a female thread (not shown) for screwing in the set screw 35. The set screw 35 is a member for fixing the seal member 40 housed in the seal case portion 31b to the nut 30 (housing 31).

[0028] As shown in FIGS. 1 to 3, in the ball screw device 10, a space A having a substantially annular shape is formed between the screw shaft 20 and an inner circumferential surface 31f of the seal case portion 31b.

[0029] The seal member 40 is a sealing material that seals the space A, and has an annular shape. The seal member 40 prevents foreign matter from entering the inside of the nut 30 through the space A.

[0030] As shown in FIG. 2 and FIG. 3, the seal member 40 is fixed to the housing 31 by the set screw 35 in a state where it is accommodated in the seal case portion 31b (space A). The set screw 35 is screwed into the through hole 34. The screwing position of the set screw 35 in the through hole 34 is adjusted to a position where the tip of the set screw 35 protrudes into the space A. The tip of the set screw 35 is inserted into a groove portion (groove portion 45 described later) provided on the outer circumferential surface of the seal member 40 (outer circumferential surface 43 described later). The set screw 35 is inserted into the groove portion, so that the axial displacement of the seal member 40 is restricted. The set screw 35 comes into contact with the bottom portion of the groove portion (bottom portion 55a described later), so that the circumferential displacement of the seal member 40 is restricted.

[0031] [About sealing materials] FIG. 4 is a perspective view showing a seal member according to the first embodiment. FIG. 5 is a cross-sectional view showing a seal member according to the first embodiment. FIG. 6 is a perspective view showing a core material constituting the seal member according to the first embodiment. FIGS. 4 and 5 show a seal member 40 which is an embodiment of the seal member of the present disclosure. The seal member 40 shown in FIGS. 4 and 5 is a first embodiment of the seal member 40. In the following description, the seal member 40 according to the first embodiment is also referred to as a first seal member 40X. In the following description, when simply referring to the seal member 40, a common configuration between the first seal member 40X and seal members according to other embodiments described later (a second seal member 40Y and a third seal member 40Z described later) will be described.

[0032] As shown in Figures 4 and 5, the seal member 40 of the present disclosure has an annular shape and includes a through hole 40a that penetrates in the axial direction. The seal member 40 includes an inner circumferential surface 41 on the radially inner side, end faces 42 on both axial sides, and an outer circumferential surface 43 on the radially outer side. The seal member 40 further includes a labyrinth seal portion 44 that protrudes radially inward from a part of the inner circumferential surface 41. The labyrinth seal portion 44 has a threaded shape that can be threadably engaged with the screw groove 22 (see Figures 1 to 3). The labyrinth seal portion 44 is integrated with the screw groove 22 to form a labyrinth seal.

[0033] The seal member 40 further has a groove portion 45. The groove portion 45 is a portion in which the axial center of the outer circumferential surface 43 is recessed radially inward, and is provided over the entire circumferential area (continuous in the circumferential direction). The groove portion 45 is a portion into which the tip of the set screw 35 (see Figs. 2 and 3) is inserted. The seal member 40 having such a configuration allows the set screw 35 to be inserted into the groove portion 45 regardless of the phase around the axis. Therefore, after the seal member 40 is inserted into the seal case portion 31b of the nut 30, it is not necessary to machine a hole for inserting the set screw 35 into the seal member 40 each time.

[0034] The seal member 40 further includes a slit portion 46. The slit portion 46 is a portion where the annular seal member 40 is discontinuous midway in the circumferential direction. The slit portion 46 includes a first end face 46a and a second end face 46b that face each other in the circumferential direction. The slit portion 46 serves as an opening for inserting the screw shaft 20 into the radial inside (through hole 40a) of the seal member 40. The slit portion 46 is formed by deforming the seal member 40 and separating the first end face 46a and the second end face 46b.

[0035] As shown in Figs. 4 to 6, the sealing member 40 of the present disclosure is configured to include a core material 50 and a pile material 60. The core material 50 forms the skeleton of the sealing member 40. The core material 50 is covered by the pile material 60. The sealing member 40 is configured by integrating the core material 50 and the pile material 60. In each of the drawings used in this description (Figs. 4, 8, 9, 11 to 13), the pile material 60 is shown as a dotted area.

[0036] [About the core material] Fig. 7A is a side view showing the shape of the groove in the core material. Fig. 6 shows a core material 50 according to a first embodiment. In the following description, the core material 50 according to the first embodiment is also referred to as a first core material 50X. In the following description, when simply referring to a core material 50, a configuration common to the first core material 50X and core materials according to other embodiments (second core material 50Y and third core material 50Z) described later will be described.

[0037] As shown in Fig. 6, the core material 50 has an annular shape and has a through hole 50a penetrating in the axial direction, an inner peripheral surface 51, an axial end face 52, and an outer peripheral surface 53. The core material 50 of this embodiment is, for example, a one-piece molded product made of rubber or resin. The core material 50 may be made of metal. The core material 50 further has a labyrinth seal portion 54 protruding radially inward from the inner peripheral surface 51. The labyrinth seal portion 54 has a convex shape equivalent to a screw thread, and is configured to be screwable onto a screw shaft 20 (see Figs. 1 to 3) having a screw thread 21 and a screw groove 22.

[0038] As shown in Fig. 6 and Fig. 7A, the core material 50 further has a groove portion 55 formed on the outer circumferential surface 53. The groove portion 55 is continuous in the circumferential direction. It is preferable that the groove portion 55 has a shape in which the groove width on the radially outer side is wider than the groove width on the radially inner side. In this case, the set screw 35 inserted from the radially outer side can easily enter the groove portion 55, and the gap between the set screw 35 that has entered the groove portion 55 can be kept small. The shape of the groove portion 55 is not limited to the stepped shape shown in this embodiment, and may be, for example, a V-shaped groove.

[0039] As shown in FIG. 5, the inner circumferential surface 51 is covered with the pile material 60 to form the inner circumferential surface 41 of the seal member 40. The end surface 52 is covered with the pile material 60 to form the end surface 42 of the seal member 40. The outer circumferential surface 53 is covered with the pile material 60 to form the outer circumferential surface 43 of the seal member 40. The labyrinth seal portion 54 is covered with the pile material 60 to form the labyrinth seal portion 44 of the seal member 40. By attaching the pile material 60 so as to follow the unevenness of the labyrinth seal portion 54, the seal member 40 can ensure excellent sealing properties by the labyrinth seal portion 44. The groove portion 55 is formed as the groove portion 45 of the seal member 40.

[0040] As shown in FIG. 6, the core material 50 further has a slit portion 56. The slit portion 56 is a portion where the annular core material 50 is discontinuous midway in the circumferential direction. The slit portion 56 includes a first end face 56a and a second end face 56b that face each other in the circumferential direction. The first end face 56a is covered by a pile material 60 to form the first end face 46a of the slit portion 46 (see FIG. 4). The second end face 56b is covered by the pile material 60 to form the second end face 46b of the slit portion 46 (see FIG. 4).

[0041] As shown in Fig. 6, the core material 50 further has a pinhole 58 formed in the end surface 52. As shown in Fig. 5, the pinhole 58 is a hole into which a needle-like fixing member 70 (needle-shaped portion 71) described later is inserted. Note that the pinhole 58 may be omitted when the pile material 60 is fixed to the sealing member 40 only by adhesive. Also, the pinhole 58 does not have to be formed in advance in the end surface 52, and may be formed by piercing the fixing member 70 (needle-shaped portion 71) into the end surface 52.

[0042] [About pile material] The pile material 60 (see Figs. 4 and 5) constituting the sealing member 40 of the present disclosure is a fiber material mainly made of polyester. The pile material 60 is a pile knitted fabric including cut pile protruding from the surface. The pile material 60 may be a fiber material made of PFA (perfluoroalkoxyalkane) or PTFE (polytetrafluoroethylene).

[0043] The adhesive used to fix the pile material 60 to the core material 50 is, for example, a hot melt adhesive, more specifically, a rubber-based or polyester-based hot melt adhesive. By using a hot melt adhesive, for example, swelling can be suppressed when a liquid such as a coolant liquid penetrates into the seal member 40 during use of the ball screw device 10, and peeling of the pile material due to swelling of the adhesive can be suppressed. If there is a low possibility of swelling during use of the ball screw device 10, a solvent-based adhesive that exerts its adhesive function by drying an organic solvent may be used as the adhesive, or a water-based adhesive containing vinyl acetate resin as a component may be used, or a double-sided tape may be used. In addition, if a fixing member 70 is used to fix the pile material 60 to the core material 50, the use of an adhesive may be omitted.

[0044] Conventional sealing members such as nonwoven fabric seals, wiper-type resin seals, and brush seals have surface or line contact between the sealing member and the screw shaft. On the other hand, the sealing member 40 of this embodiment uses pile material 60, so that the contact between the pile material 60 (the tip of the cut pile) and the screw shaft 20 becomes point contact, and the resistance that the sealing member 40 gives to the screw shaft 20 can be reduced. In addition, the sealing member 40 of this embodiment uses pile material 60, so that the sealing performance against foreign matter, dust, etc. can be ensured, and the retention of grease used in the nut 30 can be improved.

[0045] In the sealing member 40 of the present disclosure, at least the inner peripheral surface 51 and the end surfaces 52 of the core material 50 are covered by the pile material 60. Note that in the sealing member 40 of the present disclosure, the pile material 60 may further cover the outer peripheral surface 53 of the core material 50. In this case, the pile material 60 may cover the range of the outer peripheral surface 53 excluding the groove portion 55, or may cover the entire range of the outer peripheral surface 53 including the groove portion 55.

[0046] [About fixing parts] As shown in FIG. 4 and FIG. 5, the sealing member 40 of the present disclosure further includes a fixing member 70. The fixing member 70 shown in this embodiment is a staple (a substantially U-shaped nail) and has two needle-shaped portions 71 which are needle-shaped protrusions. The needle-shaped portions 71 are inserted into the pinholes 58 of the core material 50. In the sealing member 40, the pile material 60 is attached to the inner circumferential surface 51 and the end surface 52 of the core material 50 by the adhesive, and is fastened to the end surface 52 of the core material 50 by the fixing member 70. In the sealing member 40 of this embodiment, the core material 50 and the pile material 60 are integrated using the fixing member 70 and an adhesive. In the sealing member 40 of this embodiment, the pile material 60 is fastened to the core material 50 by the fixing member 70. For this reason, even if the sealing member 40 is used in an environment where moisture is present and there is a concern that the adhesive will swell and cause a decrease in adhesive strength, the pile material 60 can be reliably prevented from peeling off from the core material 50. The fixing member 70 does not have to be in the form of a staple (a substantially U-shaped nail) and may be, for example, a substantially I-shaped pin (nail). Furthermore, when the sealing member 40 of the present disclosure is used in an environment where there is no risk of the adhesive strength of the adhesive being reduced, the fixing member 70 may be omitted.

[0047] [Regarding the shape of the groove] FIG. 7B is a side view showing a form of a groove having a regulating portion. FIG. 7C is a side view showing another form of a groove having a regulating portion. As shown in FIG. 7B and FIG. 7C, the core material 50 constituting the seal member 40 of the present disclosure preferably has a regulating portion 59 at the bottom 55a of the groove 55. The regulating portion 59 is a portion that regulates the relative displacement between the groove 55 and the set screw 35 that is inserted into the groove 55 and contacts the bottom 55a. The seal member 40 of the present disclosure can reliably regulate the relative displacement of the bottom 55a with respect to the set screw 35 by providing the regulating portion 59. In the ball screw device 10 of the present embodiment, the regulating portion 59 regulates the relative displacement of the seal member 40 with respect to the set screw 35. The seal member 40 having the regulating portion 59 can ensure stable sealing in the space A by reliably regulating the displacement (rotation) in the circumferential direction.

[0048] The restricting portion 59 shown in FIG. 7B is configured by a roughened surface portion 59a formed on the bottom portion 55a of the groove portion 55. The roughened surface portion 59a is a portion having a larger friction coefficient than the portions of the core material 50 other than the restricting portion 59. The roughened surface portion 59a illustrated in this embodiment is a portion in which a flat knurled shape is formed on the bottom portion 55a. The shape of the roughened surface portion 59a is not limited thereto, and may be a portion in which a twill knurled shape is formed on the bottom portion 55a, a portion in which the bottom portion 55a is embossed, or the like. The roughened surface portion 59a may be formed by attaching a separate band-shaped member having a roughened surface to the bottom portion 55a.

[0049] The restricting portion 59 provided in the seal member 40 of the present disclosure may be configured by a plurality of recesses 59b formed in the bottom portion 55a of the groove portion 55, as shown in Fig. 7C. The recesses 59b have a shape into which the tip of the set screw 35 can be inserted. Wall portions exist between the recesses 59b adjacent in the circumferential direction, and the wall portions can be engaged with the set screws 35, thereby restricting the rotation of the seal member 40 in the circumferential direction.

[0050] [Regarding the first embodiment of the sealing member] The first seal member 40X shown in Fig. 4 and Fig. 5 is configured to include a first core material 50X shown in Fig. 6. The first core material 50X is characterized by a configuration having one slit portion 56. As shown in Fig. 4 and Fig. 5, the first seal member 40X configured to include the first core material 50X has one slit portion 46. The slit portion 46 is a portion where the circumferential direction of the annular first seal member 40X is discontinuous. The slit portion 46 includes a first end face 46a and a second end face 46b that face each other in the circumferential direction.

[0051] When the first seal member 40X is deformed to separate the first end face 46a and the second end face 46b in the circumferential direction and / or the axial direction, the slit portion 46 forms an opening through which the screw shaft 20 (see Figs. 1 to 3) can be inserted into the through hole 40a from the radial outside. The first seal member 40X having the slit portion 46 serving as the opening can be attached to the middle part of the screw shaft 20 in the axial direction when it is attached to the screw shaft 20. In other words, the first seal member 40X can be attached to the screw shaft 20 not only from the end part of the screw shaft 20 in the axial direction. In addition, the first seal member 40X can be removed from the middle part of the screw shaft 20. Therefore, the ball screw device 10 using the first seal member 40X does not need to be disassembled extensively to expose the end part of the screw shaft 20 when replacing the first seal member 40X. Furthermore, when the first seal member 40X having such a configuration is used, the user can easily, with one hand, attach the first seal member 40X to the intermediate portion of the screw shaft 20. Therefore, the ball screw device 10 employing the first seal member 40X can efficiently perform the replacement work of the first seal member 40X.

[0052] In the first seal member 40X, the first end face 46a and the second end face 46b are each covered with the pile material 60. Therefore, after the first seal member 40X is attached to the space A, the gap existing between the first end face 46a and the second end face 46b is sealed by the pile material 60. Therefore, the first seal member 40X can ensure sealing performance even when the slit portion 46, which may be a weak point in sealing performance, is provided.

[0053] [Second embodiment of the sealing member] FIG. 8 is a side view showing a seal member according to the second embodiment (with the slit portion closed). FIG. 9 is a side view showing a seal member according to the second embodiment (with the slit portion open). FIG. 10 is a side view showing a core material constituting the seal member according to the second embodiment. FIGS. 8 and 9 show a seal member 40 according to a second embodiment of the present disclosure. In the following description, the seal member 40 according to the second embodiment is also referred to as a second seal member 40Y. The second seal member 40Y differs from the first seal member 40X (see FIG. 4) in that it is provided with a cutout portion 47.

[0054] The second seal member 40Y shown in Fig. 8 and Fig. 9 includes a core material 50 according to the second embodiment shown in Fig. 10. The core material 50 according to the second embodiment shown in Fig. 10 is also referred to as a second core material 50Y. The second core material 50Y is different from the first core material 50X (see Fig. 6) in that it has one notch portion 57 at a position facing the slit portion 56 in the radial direction, and the other configuration is common to the first core material 50X. The notch portion 57 includes a first inclined surface 57a and a second inclined surface 57b. The first inclined surface 57a and the second inclined surface 57b are in contact with each other at a contact point 57c on the radial inside, and have a V-shaped shape when viewed from the axial direction. The notch portion 57 constitutes the notch portion 47 of the second seal member 40Y by covering the first inclined surface 57a and the second inclined surface 57b with the pile material 60 (see Fig. 8). It is preferable that the first inclined surface 57a and the second inclined surface 57b are connected at the contact point 57c, but they may be spaced apart.

[0055] The cutout portion 47 is provided at a position facing the slit portion 46 in the radial direction. The cutout portion 47 includes a first inclined surface 47a and a second inclined surface 47b. The first inclined surface 47a and the second inclined surface 47b are in contact with each other at a contact point 47c on the radially inner side, and have a V-shaped form when viewed from the axial direction. The first inclined surface 47a and the second inclined surface 47b are covered by a pile material 60. In the second seal member 40Y, the pile material 60 covering the inner circumferential surface 51 is continuous in the circumferential direction at the contact point 47c on the radially inner side. In other words, in the second seal member 40Y, the first inclined surface 47a and the second inclined surface 47b are connected by the pile material 60 at the contact point 47c on the radially inner side. Therefore, the second seal member 40Y is not separated into two members at the cutout portion 47. In other words, the second seal member 40Y is configured as one member. The second seal member 40Y having this configuration is not separated into two members, and is therefore easy to handle when performing one-handed operations.

[0056] As shown in FIG. 9, the second seal member 40Y can open the slit portion 46 to a position where the first inclined surface 47a and the second inclined surface 47b come into contact with each other, with the contact point 47c as a fulcrum. Therefore, the second seal member 40Y can open the slit portion 46 wider than the first seal member 40X (see FIG. 4) described above, and the slit portion 46 has a larger opening. The second seal member 40Y having such a configuration allows the screw shaft 20 (see FIGS. 1 to 3) to be easily inserted through the slit portion 46, making it easier to attach the second seal member 40Y to the middle portion of the screw shaft 20. When the second seal member 40Y having such a configuration is used, the user can more easily attach the second seal member 40Y to the middle portion of the screw shaft 20 with one hand.

[0057] [Auxiliary sealing materials] FIG. 11 is a perspective view showing the attached state of the auxiliary seal member in the seal member according to the second embodiment. The cutout portion 47 can be a weak point that reduces the sealing property of the second seal member 40Y. For this reason, as shown in FIG. 11, it is more preferable that the second seal member 40Y having the cutout portion 47 has an auxiliary seal member 48 that fills the cutout portion 47. The auxiliary seal member 48 has a wedge-shaped form that fills the cutout portion 47. It is preferable that the auxiliary seal member 48 is made of the same material as the material that constitutes the core material 50. The auxiliary seal member 48 may have a pile material 60 attached to its surface. A part of the auxiliary seal member 48 is fitted into the groove portion 55, which prevents the second seal member 40Y from being displaced in the axial direction. By configuring the second seal member 40Y to include the auxiliary seal member 48, it is possible to further facilitate the replacement work compared to the first seal member 40X, while ensuring the same sealing property as the first seal member 40X.

[0058] [Regarding the third embodiment of the sealing member] FIG. 12 is a perspective view showing a seal member according to a third embodiment. FIG. 13 is a perspective view showing a seal member (divided state) according to a third embodiment. FIG. 14 is a perspective view showing a core material constituting the seal member according to the third embodiment. FIGS. 12 and 13 show a seal member 40 according to a third embodiment of the present disclosure. In the following description, the seal member 40 according to the third embodiment is also referred to as a third seal member 40Z. The third seal member 40Z is different from the first seal member 40X (see FIG. 4) and the second seal member 40Y (see FIG. 8) in that it has two slit portions 46 and is configured to be disassembled into two members, but has a common configuration with the first seal member 40X in other respects. The third seal member 40Z is configured to include a first member 401 and a second member 402.

[0059] The third seal member 40Z shown in Figures 12 and 13 includes a core material 50 according to the third embodiment shown in Figure 14. The core material 50 according to the third embodiment is also referred to as a third core material 50Z.

[0060] 14, the third core material 50Z includes a first slit portion 56X which is the first slit portion 56, and a second slit portion 56Y which is the second slit portion 56. The second slit portion 56Y is provided at a position facing the first slit portion 56X in the radial direction. The third core material 50Z is configured to be separable into two at the first slit portion 56X and the second slit portion 56Y.

[0061] The third core material 50Z, which can be separated into two members, is configured to include a first member 501 and a second member 502. The first member 501 becomes the first member 401 (see FIGS. 12 and 13) when the inner circumferential surface 51 and end faces 52 are covered with the pile material 60. The second member 502 becomes the second member 402 (see FIGS. 12 and 13) when the inner circumferential surface 51 and end faces 52 are covered with the pile material 60.

[0062] The first slit portion 56X includes a first end face 56a and a second end face 56b. The first end face 56a and the second end face 56b are covered with the pile material 60 to form the first slit portion 46X of the third seal member 40Z (see FIGS. 12 and 13). The second slit portion 56Y includes a third end face 56c and a fourth end face 56d. The third end face 56c and the fourth end face 56d are covered with the pile material 60 to form the second slit portion 46Y of the third seal member 40Z (see FIGS. 12 and 13).

[0063] The third seal member 40Z has each of its circumferential end faces 56a to 56d covered with the pile material 60, so that the pile material 60 is disposed in the gap between the first end face 46a and the second end face 46b and in the gap between the third end face 46c and the fourth end face 46d. Therefore, the third seal member 40Z has the first slit portion 46X (the gap between the first end face 46a and the second end face 46b) and the second slit portion 46Y (the gap between the third end face 46c and the fourth end face 46d) sealed by the pile material 60.

[0064] Since the third seal member 40Z has a plurality of slit portions 46 (first slit portion 46X and second slit portion 46Y), each slit portion 46 can be a weak point that reduces the sealing property of the seal member 40. The third seal member 40Z is configured such that the gap between the first end face 46a and the second end face 46b and the gap between the third end face 46c and the fourth end face 46d are sealed by the pile material 60 in each slit portion 46 (first slit portion 46X and second slit portion 46Y). The third seal member 40Z having such a configuration can ensure the same sealing property as the first seal member 40X, even though it is configured to be separable into two.

[0065] [About connecting parts] As shown in FIG. 13 and FIG. 14, the third seal member 40Z includes a connecting member 49 that connects the first member 401 and the second member 402. The connecting member 49 in this embodiment is a metal dowel. The connecting member 49 does not have to be made of metal, and may be made of, for example, resin. The first to fourth end faces 46a to 46d are each provided with a dowel hole (not shown) for inserting the connecting member 49. The third seal member 40Z connects the first member 401 and the second member 402 by inserting the connecting member 49 to a predetermined depth into each dowel hole in the first end face 46a and the second end face 46b, and inserting the connecting member 49 to a predetermined depth into each dowel hole in the third end face 46c and the fourth end face 46d. In this embodiment, a configuration in which a connecting member 49 is provided in both the first slit portion 46X and the second slit portion 46Y is exemplified, but the connecting member 49 may be provided in only one of the first slit portion 46X and the second slit portion 46Y.

[0066] Furthermore, if one of the multiple slit portions 46 (first slit portion 46X and second slit portion 46Y) of the third seal member 40Z is connected by the connecting member 49 while the other is left unconnected, the user can open the other slit portion 46 with one hand. This allows the user to attach the third seal member 40Z to the middle portion of the screw shaft 20 (see FIGS. 1 to 3) with one hand. Therefore, the ball screw device 10 employing the third seal member 40Z allows efficient replacement of the third seal member 40Z.

[0067] [Actions and Effects of the Present Embodiment] (1) The seal member 40 of this embodiment is a seal member disposed in a substantially annular space A between a screw shaft 20 and a nut 30 in a ball screw device 10 having the screw shaft 20 and a nut 30. The seal member 40 includes a circular core material 50 and a pile material 60 that covers at least an inner circumferential surface 51 and an axial end surface 52 of the core material 50. The seal member 40 has a slit portion 46 that is discontinuous midway in the circumferential direction.

[0068] The seal member 40 of this embodiment allows a user to hold the seal member 40 with one hand and open the slit portion 46. Therefore, the seal member 40 can be attached to the middle portion of the screw shaft 20 with one hand. The seal member 40 configured in this manner facilitates the attachment work of the seal member 40 used in the ball screw device 10 to the middle portion in the axial direction of the screw shaft 20. Therefore, the ball screw device 10 equipped with the seal member 40 of this embodiment improves the workability in replacing the seal member 40.

[0069] (2) The sealing member 40 of this embodiment further includes a fixing member 70 that fixes the pile material 60 to the axial end surface 52 of the core material 50. In the sealing member 40, the core material 50 has a pinhole 58 formed in the axial end surface 52. The fixing member 70 has a needle-shaped portion 71 that is inserted into the pinhole 58. The needle-shaped portion 71 is inserted into the pinhole 58 in a state in which it pierces the pile material 60. The sealing member 40 having such a configuration can reliably fix the pile material 60 to the core material 50. The sealing member 40 has a configuration that can facilitate the installation work to the axial intermediate portion of the screw shaft 20, while suppressing the peeling of the pile material 60 from the core material 50, thereby ensuring the sealing performance of the sealing member 40.

[0070] (3) In the first seal member 40X of this embodiment, the slit portion 46 has a first end face 46a and a second end face 46b that face each other in the circumferential direction. The pile material 60 further covers the first end face 46a and the second end face 46b. In the first seal member 40X of this embodiment, the pile material 60 can seal any gaps that may exist in the slit portion 46. This ensures the sealing performance of the seal member 40 having the slit portion 46.

[0071] (4) The second seal member 40Y of the present embodiment further has a notch portion 47 formed at a position facing the slit portion 46 in the radial direction. The second seal member 40Y of the present embodiment has the notch portion 47, which makes it possible to open the gap in the slit portion 46 more widely. This makes it easier to insert the screw shaft 20 from the gap in the slit portion 46 to the radial inside of the seal member 40.

[0072] (5) The second seal member 40Y of the present embodiment further includes an auxiliary seal member 48 that fills the cutout portion 47. According to the second seal member 40Y of the present embodiment, the cutout portion 47 can be sealed by the auxiliary seal member 48. This ensures the sealing performance of the seal member 40 having the cutout portion 47.

[0073] (6) In the second seal member 40Y of the present embodiment, the pile material 60 covering the inner circumferential surface 51 of the core material 50 is continuous in the circumferential direction at the cutout portion 47. According to the second seal member 40Y of the present embodiment, the seal member 40 having the cutout portion 47 can be configured as a single member that is not separated. Therefore, the second seal member 40Y can be more easily attached to the intermediate portion of the screw shaft 20.

[0074] (7) In the seal member 40 of this embodiment, the core material 50 has a groove portion 55 formed over the entire circumferential area on the outer circumferential surface 53. The seal member 40 of this embodiment does not require the formation of a hole for inserting the set screw 35 every time the seal member 40 is replaced. Furthermore, the seal member 40 having such a configuration allows the set screw 35 to be inserted into the groove portion 55 (groove portion 45) regardless of the circumferential phase. This improves the workability of the replacement work for the seal member 40 used in the ball screw device 10.

[0075] (8) In the seal member 40 of this embodiment, the core material 50 has a regulating portion 59 at the bottom 55a of the groove portion 55 that regulates relative displacement between the core material 50 and the set screw 35 abutting against the bottom 55a. According to the seal member 40 of this embodiment, the regulating portion 59 can suppress phase shift in the circumferential direction of the seal member 40 attached to the nut 30 after attachment. This ensures stable sealing performance for the seal member 40. [Explanation of symbols]

[0076] 10 Ball screw device (screw device) 20 Screw shaft 30 Nut 40 Sealing material 40X First seal member 40Y Second seal member 40Z 3rd seal member 45 Groove 46 Slit section 46a 1st end face 46b 2nd end face 47 Cutout 48 Auxiliary seal member 50 Core material 51 Inner surface 52 End face 53 Outer surface 55a bottom 58 Needle hole 59 Regulatory Department 60 Pile material 70 Fixing member 71 Needle A Space

Claims

1. A seal member disposed in a substantially annular space between a screw shaft and a nut in a screw device having a screw shaft and a nut, A circular core material; A pile material covering at least an inner peripheral surface and an axial end surface of the core material; Including, A seal member having a slit portion that is discontinuous midway in the circumferential direction.

2. The pile material may further include a fixing member that fixes the pile material to an axial end surface of the core material, The core material has a pinhole formed on an end surface in the axial direction, The fixing member has a needle-shaped portion to be inserted into the pinhole, The sealing member according to claim 1 , wherein the needle-shaped portion is inserted into the pin hole in a state where the needle-shaped portion pierces the pile material.

3. The slit portion has a first end surface and a second end surface opposed to each other in a circumferential direction, The sealing member according to claim 1 or 2, wherein the pile material further covers the first end surface and the second end surface.

4. The seal member according to claim 1 or 2, further comprising a notch portion formed at a position radially opposite to the slit portion.

5. The seal member according to claim 4 , further comprising an auxiliary seal member filling the notch portion.

6. The seal member according to claim 4 , wherein the pile material covering the inner peripheral surface of the core material is continuous in the circumferential direction at the cutout portion.

7. The seal member according to claim 1 or 2, wherein the core member has a groove portion formed on an outer circumferential surface thereof over an entire area in a circumferential direction.

8. The seal member according to claim 7 , wherein the core member has a restricting portion at a bottom of the groove portion, the restricting portion restricting relative displacement between the core member and a member in contact with the bottom portion.

Images