JP2008281205A - Seal for ball screw, and ball screw using this seal for ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal for ball screw which can simultaneously satisfy 2 capabilities in which lubricant inside ball screw can be secured, and foreign substance can be prevented from being entered inside ball screw nut from outside. <P>SOLUTION: The ball screw is characterized in that in an axial direction of ball screw nut 13, at least one of foreign substance removing member 16 located outside, and a sealing member 17 located more inside than the foreign substance removing member 16 located outside are provided, in that in an inner periphery of the foreign substance removing member 16, a projection 28a profiled in spiral interfit to a ball rolling surface 12a of a ball screw shaft 12 is arranged, and in that at a location from an end surface 28c facing outside in an axial direction of the ball screw nut 13 of the foreign substance removing member 16 to a halfway of the foreign substance removing member 16, an aperture 32 for removing the foreign substance which discharges the foreign substance after being combed up to the outside of the ball screw nut 13 is arranged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ball screw seal that is attached to both ends of a ball screw nut and seals the inside of the ball screw nut, and a ball screw using the ball screw seal.

  Conventionally, as this kind of ball screw seal, as shown in FIG. 14, a ball screw seal (see Japanese Patent Laid-Open No. 2000-230619) in which a synthetic resin thin plate is formed in a ring shape and the inner peripheral edge thereof is sharpened. Are known. In the ball screw seal 1, foreign matters such as dust enter from the outside into the gap between the screw shaft 2 and the ball screw nut 3 because the inner peripheral edge of the seal 1 is in contact with the outer peripheral surface of the screw shaft 2 and the screw groove. Is preventing.

  As another ball screw seal, as shown in FIG. 15, a plurality of thin seal plates 4 of the same material are stacked, and the ends of the stacked seal plates are contacted with the screw shaft. It is known (see Japanese Utility Model Publication No. 5-4330). In this ball screw seal, the inner peripheral edge of the thin seal plate 4... Is in contact with the outer peripheral surface of the screw shaft 7 and the screw groove, so that a gap between the ball screw shaft 7 and the ball screw nut 6 is obtained. This prevents foreign matter such as dust from entering.

Japanese Patent Laid-Open No. 2000-230619 No. 5-4330

  However, in the conventional ball screw seal described in Japanese Patent Application Laid-Open No. 2000-230619, foreign matter such as dust can be prevented from entering the ball screw nut 3 from the outside, but the outer periphery of the screw shaft It is inevitable that the lubricant adhering to the surface and the thread groove passes through the ball screw seal and leaches out from the inside of the ball screw nut 3, and as a result, the lubricant inside the ball screw nut 3 cannot be retained. Problems arise.

  Further, in the ball screw seal described in Japanese Utility Model Publication No. 5-4330, since a plurality of thin plate-like seal plates 4 are stacked, it is possible for foreign matter to enter the ball screw nut 6. However, it is inevitable that the lubricant adhering to the outer peripheral surface of the screw shaft and the thread groove passes through the ball screw seal and leaches out from the inside of the ball screw nut 3. 3 The problem that the internal lubricant cannot be retained occurs.

  Accordingly, the present invention provides a ball screw seal that can prevent the entry of foreign matter from the outside to the inside of the ball screw nut and can simultaneously satisfy the two functions of holding the lubricant inside the ball screw nut, and the ball. It is an object of the present invention to provide a ball screw using a screw seal.

  The present invention will be described below. In addition, in order to make an understanding of this invention easy, the reference number of an accompanying drawing is attached in parenthesis writing, However, This invention is not limited to the form of illustration.

  The inventor has laminated a foreign matter removing member for preventing foreign matter from entering from the outside to the inside of the ball screw nut and a sealing member for holding the lubricant inside the ball screw nut. By bringing the circumference into contact with the screw shaft, two functions of removing foreign substances and retaining the lubricant were obtained simultaneously.

  That is, the invention of claim 1 is a ball screw seal (15) mounted on both ends of the ball screw nut (13), and the hole (16a) corresponding to the cross-sectional shape perpendicular to the axis of the ball screw shaft (12). A foreign matter removing member (16) for preventing foreign matter from entering from the outside to the inside of the ball screw nut (13), and a hole (17a corresponding to the cross-sectional shape perpendicular to the axis of the ball screw shaft (12). ) And a sealing member (17) for holding the lubricant inside the ball screw nut (13), and the foreign matter removing member (16) and the sealing member (17) are overlapped with each other. , Each inner circumference is in contact with the ball rolling surface (12a) and the outer circumferential face (12b) of the ball screw shaft (12), and at least one located outside in the axial direction of the ball screw nut (13). Horn An object removing member (16) and a sealing member (17) positioned on the inner side of the foreign matter removing member (16) located on the outer side, and the ball screw is disposed on an inner periphery of the foreign matter removing member (16). A spiral protrusion (28a) that fits on the ball rolling surface (12a) of the shaft (12) is provided, and the end surface of the foreign matter removing member (16) that faces outward in the axial direction of the ball screw nut (13) A foreign matter removing opening (32...) For scraping the foreign matter and discharging it to the outside of the ball screw nut (13) is provided from (28c) to the middle of the foreign matter removing member (16). The above-mentioned problem is solved by the ball screw seal (15).

  According to the present invention, the edge formed by the foreign matter removing opening functions as a scraper, and the foreign matter adhering to the outer peripheral surface of the ball screw shaft and the ball rolling surface is lifted and discharged to the outside of the ball screw. Can be removed more reliably. Also, this edge may scrape out the lubricant inside the ball screw nut, but the lubricant inside the ball screw nut is held by the sealing member, so keep the lubricant scraped off at the edge to a minimum. Can do.

  According to a second aspect of the present invention, in the ball screw seal according to the first aspect, the sealing member (17) is made of a soft material, and the foreign matter removing member (16) is a hard material harder than the soft material. It is characterized by comprising.

  Here, the foreign substance removing member and the sealing member may be manufactured from the same material or different materials as long as they have different hardnesses.

  According to the present invention, the foreign material removing member made of a hard material can easily have a function of preventing foreign materials from entering from the outside to the inside of the ball screw nut. On the other hand, since the sealing member made of a soft material softly adheres to the outer peripheral surface of the screw shaft and the surface of the ball rolling surface, the adhesion between the sealing member and the outer peripheral surface of the screw shaft and the ball rolling surface can be improved. For this reason, the function of the sealing member holding the lubricant can be improved.

  Further, the invention of claim 3 is characterized in that in the ball screw seal of claim 1, the sealing member (17) can absorb the lubricant.

  According to this invention, since the sealing member absorbs the lubricant adhering to the outer peripheral surface of the screw shaft and the outer peripheral surface of the ball rolling surface, the function of the sealing member to retain the lubricant inside the ball screw nut is improved. be able to.

  Furthermore, the invention of claim 4 is the ball screw seal according to any one of claims 1 to 3, wherein each of the foreign matter removing member (16) and the sealing member (17) is shifted by a predetermined angle in the circumferential direction. It has a positioning part (18 ...) so that it may be piled up in a state.

  The cross section perpendicular to the axis of the ball screw shaft is an irregular circular shape. This irregular circular shape is the same shape even if its position is different in the axial direction of the screw shaft, but the phase is shifted in the circumferential direction. For this reason, it is necessary to consider the phase when laminating the foreign matter removing member and the sealing member. According to the present invention, since the foreign substance removing member and the sealing member have the positioning portions so as to be overlapped with each other while being shifted by a predetermined angle in the circumferential direction, the foreign substance removing member and the sealing member can be easily stacked.

  Further, according to the present invention, a ball screw shaft (12) having a ball rolling groove (12a) on the outer periphery and a plurality of rolls capable of rolling along the ball rolling groove (12a). A ball (14), a ball screw nut (13) screwed onto the ball screw shaft (12) via the plurality of balls (14), and a ball screw nut (13). A ball screw having ball screw seals (15) mounted at both ends has a hole (16a) corresponding to a cross-sectional shape perpendicular to the axis of the ball screw shaft (12), and is external to the ball screw nut (13). A foreign matter removing member (16) for preventing foreign matter from entering the inside, and a hole (17a) corresponding to a cross-sectional shape perpendicular to the axis of the ball screw shaft (12), and the inside of the ball screw nut (13) Sealing member for retaining lubricant 17), and the foreign matter removing member (16) and the sealing member (17) are overlapped with each other, and the inner periphery thereof is the ball rolling surface (12a) and the outer peripheral surface (12b) of the ball screw shaft (12). ), The sealing member (17) is located on the inner side of the foreign matter removing member (16) located on the outer side in the axial direction of the ball screw nut (15), and the inside of the foreign matter removing member (16) A spiral protrusion (28a) that fits on the ball rolling surface (12a) of the ball screw shaft (12) is provided around the circumference, and the ball screw nut (13) of the foreign matter removing member (16) is provided. A foreign matter removal opening (32...) For scraping foreign matter and discharging it to the outside of the ball screw nut (13) from the end surface (28c) facing outward in the axial direction to the middle of the foreign matter removal member (16). Special features It can also be configured as a ball screw to be.

  As described above, in the present invention, the ball screw seal has a hole corresponding to the cross-sectional shape perpendicular to the axis of the ball screw shaft, and the foreign matter for preventing foreign matter from entering from the outside to the inside of the ball screw nut. A removal member and a sealing member that has a hole corresponding to the cross-sectional shape perpendicular to the axis of the ball screw shaft and holds the lubricant inside the ball screw nut. The foreign substance removing member and the sealing member are overlapped with each other, and the inner circumferences thereof are in contact with the ball rolling surface and the outer circumferential surface of the ball screw shaft. The foreign matter removing member is located outside in the axial direction of the ball screw nut, and the sealing member is located inside the foreign matter removing member located outside in the axial direction of the ball screw nut.

  According to the present invention, the foreign matter removing member located outside contacts the outer peripheral surface of the screw shaft and the ball rolling surface, so that foreign matter can be prevented from entering from the outside to the inside of the ball screw nut. Moreover, since the sealing member located inside the foreign material removing member contacts the outer peripheral surface of the screw shaft and the surface of the ball rolling groove, the lubricant inside the ball screw nut can be held. Accordingly, it is possible to obtain a ball screw seal that can simultaneously prevent the entry of foreign matter from the outside of the ball screw nut into the inside and simultaneously satisfy the two functions of holding the lubricant inside the ball screw nut inside the ball screw nut. .

  Further, according to the present invention, the edge formed by the foreign matter removing opening functions as a scraper, and the foreign matter adhering to the outer peripheral surface of the ball screw shaft and the ball rolling surface is lifted and discharged to the outside of the ball screw. Foreign substances can be removed more reliably. Also, this edge may scrape out the lubricant inside the ball screw nut, but the lubricant inside the ball screw nut is held by the sealing member, so keep the lubricant scraped off at the edge to a minimum. Can do.

  1 and 2 show a ball screw incorporating a ball screw seal according to a first embodiment of the present invention. The ball screw 11 has a ball screw shaft 12 (hereinafter simply referred to as a screw shaft) having a ball rolling groove 12a as a spiral ball rolling surface on the outer peripheral surface, and the ball rolling groove 12a on the inner peripheral surface. A ball screw nut 13 having a spiral ball rolling groove 13a (hereinafter simply referred to as a nut), and a plurality of balls arranged and accommodated between the ball rolling groove 13a of the nut 13 and the ball rolling groove 12a of the screw shaft 12 With. When the screw shaft 12 is rotated, the balls 14... Roll between the ball rolling groove 12 a of the screw shaft 12 and the ball rolling groove 13 a of the nut 13. The ball reaching one end of the ball rolling groove 13a is returned to the other end of the ball rolling groove 12a through a return tube (not shown) fixed to the nut 13.

  A pair of seal member mounting holes 13b and 13b are formed at both ends of the nut 13 in the axial direction. A ring-shaped ball screw seal 2 is mounted in each of the seal member mounting holes 13b and 13b, and is pressed against the wall surface 13c of the mounting hole 13b by a retaining ring 20.

  The ball screw seal 15 is configured by sandwiching a thin plate-like sealing member 17 from both sides with thin plate-like foreign matter removing members 16, 16. The foreign matter removing members 16 and 16 and the sealing member 17 have holes 16 a and 17 a corresponding to the cross-sectional shape perpendicular to the axis of the screw shaft 12. The shapes of the inner circumferences of the foreign matter removing members 16 and 16 and the sealing member 17 are similar to the cross section of the screw shaft 12 in the direction perpendicular to the axis, and have a slight tightening margin with respect to the shape of the screw shaft 12 perpendicular to the axis. The inner periphery of each of the foreign matter removing members 16 and 16 and the sealing member 17 is in contact with the ball rolling groove 12a and the outer peripheral surface 12b of the screw shaft 12.

  The sealing member 17 is made of a thin plate having a thickness of about 1 mm, and is manufactured by a so-called cutting process in which a sheet-like plate material is punched out by a press. The sealing member 17 is manufactured from a porous material having a high porosity such as a nonwoven fabric such as wool felt or a sintered PE (sintered polyethylene) so as to absorb the lubricating oil. The sealing member 17 is manufactured from a soft material that is softer than the foreign matter removing member 16 described later. The sealing member 17 is preferably made of a material having excellent wear resistance, chemical resistance, and heat resistance.

  The foreign matter removing members 16 and 16 are also made of a thin plate having a thickness of about 1 mm, and are manufactured by so-called cutting processing in which a sheet-like plate material is punched out by a press. The foreign matter removing members 16 and 16 are manufactured from a material such as synthetic resin or hard rubber such as PTFE (Teflon (registered trademark) + graphite), UPE (ultra high molecular weight polyethylene), PA (polyamide resin). The foreign matter removing members 16 and 16 are manufactured from a hard material harder than the sealing member 17. It is desirable that the foreign matter removing members 16 and 16 be made of a material having good sliding properties and excellent wear resistance, chemical resistance, and heat resistance.

  FIG. 3 shows the foreign matter removing members 16 and 16 and the sealing member 17 as seen from the axial direction of the screw shaft 12. The three foreign substance removing members 16 and 16 and the sealing member 17 all have the same planar shape, the outer periphery thereof is formed in a circular shape, and the inner periphery thereof is matched with the cross section perpendicular to the axis of the screw shaft 12. It is formed into an irregular circle. Between the inner periphery and the outer periphery of the foreign matter removing members 16 and 16 and the sealing member 17, holes as positioning portions 18... Are formed on the same circumference with a predetermined angle in the circumferential direction. The angle α between the holes is determined from the lead of the screw shaft 12 and the thickness of the foreign matter removing members 16 and 16 and the sealing member 17. Specifically, in the case of a single thread, the angle α between the adjacent positioning portions 18, 18 is obtained from α = (plate thickness / lead) × 360 °. For example, when the lead is 10 mm and the seal thickness is 1 mm, the predetermined angle α is 36 °.

  The sealing member 17 is overlapped with the outer foreign matter removing member 16 being rotated by 36 °, and the inner foreign matter removing member 16 is being overlapped with the central sealing member 17 being further rotated by 36 °. . The positioning portions 18 are not limited to holes and may be notches.

  The cross section perpendicular to the axis of the screw shaft 12 is an irregular circular shape that is not a perfect circle. This irregular circular shape is the same shape even if its position is different in the axial direction of the screw shaft 12, but the phase is shifted in the circumferential direction. For this reason, it is necessary to consider the phase of the screw shaft 12 when the foreign matter removing members 16 and 16 and the sealing member 17 are laminated. In this embodiment, since the foreign matter removing members 16 and 16 and the sealing member 17 have the positioning portions 18... So as to be overlapped with each other while being shifted by a predetermined angle in the circumferential direction, the foreign matter removing members 16 and 16 considering the phase. And the sealing member 17 can be easily stacked.

  The thicknesses of the foreign matter removing members 16 and 16 and the sealing member 17 are made thin, and a plurality of the foreign material removing members 16 and 16 and the sealing member 17 are stacked so that the inner circumferences of the foreign matter removing members 16 and 16 and the sealing member 17 The outer peripheral surface 12b and the outer peripheral surface 12b of the ball rolling groove 12a can be contacted. In particular, when the screw shaft 12 is manufactured by rolling, as shown in FIG. 4, a groove-like seaming 12c is formed on the outer peripheral surface 12b of the screw shaft 12, and the foreign matter removing member is also formed on the seaming 12c. 16, 16 and the inner periphery of the sealing member 17 can be brought into close contact with each other.

  FIG. 5 shows how foreign matters are removed from the ball screw seal 15 and how the lubricant is retained. Thus, since the foreign material removal member 16 located on the outermost side contacts the outer peripheral surface 12b of the screw shaft 12 and the ball rolling groove 12a, the foreign material 30 is prevented from entering the nut from the outside. Further, since the sealing member 17 located on the inner side of the foreign matter removing member 16 softly adheres to the outer peripheral surface 12b of the screw shaft 12 and the surface of the ball rolling groove 12a and absorbs the adhered lubricant, Prevents leaching of lubricant. Therefore, it is possible to obtain the ball screw seal 15 that can simultaneously satisfy the two functions of preventing the foreign matter 30 from entering the nut from the outside and retaining the lubricant inside the nut. Thereby, the removal of the foreign material 30 and the retention of the internal oil are improved, and long-term maintenance-free is possible.

  6 and 7 show a ball screw incorporating the ball screw seal 15 according to the second embodiment of the present invention. The ball screw seal 15 includes a foreign matter removing member 16 located outside in the axial direction of the nut 13 and a sealing member 17 located inside in the axial direction of the nut. These two foreign matter removing members 16 and the sealing member 17 are superimposed on each other. The ball screw seal 22 is mounted in seal member mounting holes 13b and 13b formed at both ends of the nut 13 in the axial direction, and is pressed against the wall surfaces 13c and 13c of the mounting holes 13b and 13b by the retaining ring 20. .

  In this embodiment, since the soft sealing members 17 and 17 are sandwiched between the wall surfaces 13c and 13c formed in the mounting holes 13b and 13b of the nut 13 and the hard foreign matter removing members 16 and 16, they can be deformed. Absent. In addition, since the structure of the foreign material removal member 16, the sealing member 17, the screw shaft 12, and the nut 13 is the same as that of the said 1st Embodiment, it attaches | subjects the same code | symbol and abbreviate | omits the description.

  Even in the ball screw seal of this embodiment, the foreign matter removing member 16 located on the outside contacts the outer peripheral surface 12b of the screw shaft 12 and the ball rolling groove 12a, so that the foreign matter 30 moves from the outside to the inside of the nut. Prevent entry. Further, since the sealing member 17 located on the inner side of the foreign matter removing member 16 softly adheres to the outer peripheral surface 12b of the screw shaft 12 and the surface of the ball rolling groove 12a and absorbs the adhered lubricant, Prevents leaching of lubricant. Therefore, it is possible to obtain a ball screw seal that can simultaneously satisfy the two functions of preventing foreign matters from entering the nut from the outside and retaining the lubricant inside the nut.

  In the first embodiment and the second embodiment described above, the sealing member 17 is made of a soft material that is softer than the foreign matter removing member 16, and the sealing member 17 can absorb the lubricating oil. If the sealing member 17 is a soft material that is softer than the foreign matter removing member 16, the sealing member 17 may not be able to absorb the lubricating oil. In this case, the sealing member 17 is manufactured from non-porous synthetic resin or rubber.

  On the contrary, if the sealing member 11 can absorb the lubricating oil, the sealing member 11 may be manufactured from a hard material harder than the foreign matter removing member 16.

  8 and 9 show a ball screw incorporating a ball screw seal according to a third embodiment of the present invention. The ball screw seal 31 includes a foreign matter removing member 28 positioned on the outer side in the axial direction of the nut 13 and a sealing member 17 positioned on the inner side in the axial direction of the nut 13. The members 17 are superposed on each other. In this embodiment, unlike the above-described embodiment, the foreign matter removing member 28 is formed with a thick wall, and a spiral projection 28a that fits into the ball rolling groove of the screw shaft is formed on the inner periphery thereof. The foreign matter removing member 28 is manufactured by injection molding or cutting a synthetic resin. Since the structure of the sealing member 17 and the structure of the screw shaft 12 and the nut 13 are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

  The foreign matter removing member 28 is provided with a plurality of foreign matter removing slits 32 serving as foreign matter removing openings from the end surface 28 c facing the axially outer side of the nut 13 toward the middle of the foreign matter removing member 28. The foreign matter removing slits 32... Scrape the foreign matter 30 adhering to the screw shaft 12 and discharge it to the outside of the nut 13.

  The foreign matter removing slits 32 extend in a substantially radial direction of the screw shaft 12 and are opened so as to penetrate from the inner periphery to the outer periphery of the foreign matter removing member 28. The foreign matter removing slits 32 are formed at equal intervals in the circumferential direction. One of the opposing surfaces forming the foreign matter removing slits 32... Functions as a foreign matter removing scraper surface having an edge for scraping the foreign matter. Further, the foreign matter removing slits 32 are inclined with respect to the screw shaft lead so that the lubricant scraped by the foreign matter removing scraper surface is moved to the outside of the nut 13.

  On the outer periphery of the foreign matter removing member 28, a groove 28d extending in the circumferential direction is formed. A spring 33 is wound around the groove 28d. By winding the spring 33 around the outer periphery of the foreign matter removing member 28, the foreign matter removing member 28 can be brought into close contact with the screw shaft to improve the sealing performance, and the edge of the foreign matter scraping scraper surface can be brought into tight contact with the screw shaft 12. It is possible to scrape foreign matter with certainty.

  FIG. 10 shows a state of removing foreign matter and retaining a lubricant in the ball screw seal according to the third embodiment. Even in the ball screw seal of this embodiment, the foreign matter removing member 28 located outside contacts the ball rolling groove 12a of the screw shaft 12, so that the foreign matter removing member 28 prevents the foreign matter 30 from entering the nut from the outside. To do. Further, the edge formed by the foreign matter removing opening functions as a scraper, and the foreign matter adhering to the outer peripheral surface 12b of the screw shaft 12 and the outer peripheral surface of the ball rolling groove 12a is lifted and discharged to the outside of the ball screw. Can be removed more reliably.

  Further, since the sealing member 17 positioned on the inner side of the foreign matter removing member 28 softly adheres to the outer peripheral surface 12b of the screw shaft 12 and the surface of the ball rolling groove 12a and absorbs the adhered lubricant, Prevents lubricant from leaching out. The edge formed by the foreign object removal opening may be scraped to the lubricant inside the ball screw nut, but since the lubricant inside the nut is sealed by the sealing member, the lubricant scraped off at the edge is minimized. Can be stopped.

  In the foreign matter removing member 28, the spiral protrusion 28 a preferentially contacts the ball rolling groove 12 a of the screw shaft 12, thereby improving the foreign matter removing performance. For this reason, the sealing performance of the outer peripheral surface 12b of the screw shaft 12 is weaker than that of the ball rolling groove 12a. In the present embodiment, the sealing member 17 is disposed inside the foreign matter removing member 28, and the sealing member 17 is in contact with the outer peripheral surface 12b of the screw shaft 12 and the ball rolling groove 12a, so that the sealing performance is further improved. The lubricant can be held more reliably.

  In addition, this invention is not restricted to the said embodiment, You may implement in various embodiment. For example, it is not limited to a ball screw, but includes a raceway member provided with rolling element rolling parts, and a moving member provided so as to be movable along the raceway member via a number of rolling elements, linear ball spline guide, linear It can be used for a linear motion guide device such as a guide. In this case, the moving member includes a load rolling element rolling part corresponding to the rolling element rolling part of the track member, and a rolling element escape passage provided in parallel with the load rolling element rolling part at a predetermined interval. And a pair of direction change paths for circulating the rolling elements by connecting the load rolling element rolling part and the rolling element escape passage. When used in a linear motion guide device, seal member mounting holes are formed at both ends in the moving direction of the moving member, and a seal member in which the above-described foreign matter removing member and sealing member are stacked is mounted in the seal member mounting hole. .

  11 and 12 are graphs showing the results of a foreign matter removability confirmation test of the ball screw seal of the present invention. FIG. 11 shows the amount of intrusion of casting powder as foreign matter, and FIG. 12 shows the amount of intrusion of coolant as foreign matter.

  As the ball screw seal of this test, the ball screw seal of the first embodiment in which the thin plate-like sealing member 17 is sandwiched between the thin plate-like foreign substance removing members 16 and 16 from both sides is used. PTFE (Teflon (registered trademark) + graphite) is always used as the material for the foreign matter removing members 16 and 16, and various materials shown in Table 1 are selected as the material for the sealing member 17.

  In the drawing, the brush seal is a conventionally known seal member in which a large number of synthetic resins and the like are planted on the inner peripheral surface of the ring. The brush seal is not combined with the foreign matter removing members 16 and 16. In the figure, sintered PE means sintered polyethylene, PTFE means Teflon (registered trademark) + graphite, and UPE means ultrahigh molecular weight polyethylene. The soft wiper in the figure means a polyester fiber hardened with urethane rubber and has a function of absorbing lubricating oil.

  As test conditions of the graph shown in FIG. 11, casting powder is sprinkled on a ball screw nut at a rate of 120 g / 24 h (120 g in 24 hours). The amount of infiltration on the horizontal axis indicates the amount of intrusion of casting powder into the ball screw nut with the ball screw nut traveling for 50 km.

  As a test condition of the graph shown in FIG. 12, the coolant is sprinkled on the ball screw nut at a rate of 0.6 cc / min (0.6 cc per minute). The coolant intrusion amount on the horizontal axis indicates the coolant intrusion amount into the ball screw nut when the ball screw nut travels 0.5 km.

  As shown in FIGS. 11 and 12, it can be seen that when wool felt is used as the material of the sealing member 17, the infiltration amount of the casting powder can be reduced and the infiltration amount of the coolant can also be reduced. On the other hand, when PTFE made of the same material as the foreign matter removing members 16 and 16 is used as the material of the sealing member 17, it is possible to reduce the intrusion amount of the casting powder, but it is difficult to reduce the intrusion amount of the coolant. I understand that.

  FIG. 13 is a graph showing the results of a lubricant sealability confirmation test of the ball screw seal of the present invention.

  As the ball screw seal of this test, as in the foreign matter removal performance confirmation test, the thin plate-like sealing member 17 is sandwiched between the thin plate-like foreign matter removal members 16 and 16 from both sides in the first embodiment. A ball screw seal is used. PTFE (Teflon (registered trademark) + graphite) is always used as the material for the foreign matter removing members 16, 16, and various materials shown in FIG. 13 are selected as the material for the sealing member 17.

  In FIG. 13, the brush seal, sintered PE, PTFE, UPE, and soft wiper are made of the same materials as those in the foreign matter removal performance confirmation test.

  The horizontal axis of the graph shown in FIG. 13 indicates the travel distance (km), and the vertical axis indicates the amount of lubricant leaked from the inside of the ball screw nut to the outside.

  As shown in FIG. 13, it can be seen that the use of wool felt or soft wiper, which is a softer material than the foreign matter removing members 16, 16, as the material of the sealing member 17 can reduce the amount of lubricant leakage. It can also be seen that if PTFE made of the same material as the foreign matter removing members 16 and 16 is used as the material of the sealing member 17, it is difficult to reduce the amount of lubricant leakage.

The exploded sectional view showing the ball screw incorporating the seal for ball screws in a 1st embodiment of the present invention. Sectional drawing which shows the ball screw of the assembled state. The top view of a foreign material removal member and a sealing member. The side view which shows a rolling screw. FIG. 3 is an enlarged view of a part III in FIG. 2 (a view showing the removal of foreign matter from the ball screw seal and the holding state of the lubricant). The exploded sectional view showing the ball screw incorporating the seal for ball screws in the 2nd embodiment of the present invention. Sectional drawing which shows the ball screw of the assembled state. The exploded sectional view showing the ball screw incorporating the seal for ball screws in the 3rd embodiment of the present invention. Sectional drawing which shows the ball screw of the assembled state. FIG. 10 is an enlarged view of a portion X in FIG. 9 (a view showing a state of removing foreign substances from the ball screw seal and holding a lubricant). The graph which shows the result of the foreign material removal property confirmation test of the seal | sticker for ball screws of this invention (The amount of intrusion of the casting powder as a foreign material is shown). The graph which shows the result of the foreign material removal property confirmation test of the seal | sticker for ball screws of this invention (The amount of coolant penetration | invasion as a foreign material is shown). The graph which shows the result of the lubricant sealability confirmation test of the seal for ball screws of the present invention. The figure which shows the conventional ball screw seal. The figure which shows the other example of the conventional seal | sticker for ball screws.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Ball screw shaft, 12a ... Ball rolling groove (ball rolling surface), 13 ... Ball screw nut, 15, 22, 31 ... Ball screw seal, 16, 28 ... Foreign matter removing member, 16a ... hole, 17 ... sealing member, 17a ... hole, 28a ... projection, 28c ... end surface, 32 ... slip for removing foreign matter (foreign matter removing opening)

Claims (5)

A ball screw seal mounted on both ends of a ball screw nut,
A foreign matter removing member having a hole corresponding to a cross-sectional shape perpendicular to the axis of the ball screw shaft, and preventing foreign matter from entering the inside of the ball screw nut;
A hole corresponding to the cross-sectional shape perpendicular to the axis of the ball screw shaft, and a sealing member for holding the lubricant inside the ball screw nut,
The foreign matter removing member and the sealing member are overlapped with each other, and the inner periphery thereof is in contact with the ball rolling surface and the outer peripheral surface of the ball screw shaft,
In the axial direction of the ball screw nut, comprising at least one foreign matter removing member located outside, and a sealing member located inside the foreign matter removing member located outside,
On the inner periphery of the foreign matter removing member, a spiral protrusion that is fitted to the ball rolling surface of the ball screw shaft is provided,
A foreign matter removing opening for scraping the foreign matter and discharging it to the outside of the ball screw nut is provided from an end surface of the foreign matter removing member facing the axially outer side of the ball screw nut to the middle of the foreign matter removing member. Ball screw seal.   The ball screw seal according to claim 1, wherein the sealing member is made of a soft material, and the foreign matter removing member is made of a hard material harder than the soft material.   The ball screw seal according to claim 1, wherein the sealing member is capable of absorbing a lubricant.   4. The ball screw seal according to claim 1, wherein each of the foreign matter removing member and the sealing member has a positioning portion so as to be overlapped with each other while being shifted by a predetermined angle in the circumferential direction. A ball screw shaft having a ball rolling groove on the outer periphery, a plurality of balls capable of rolling along the ball rolling groove, and a ball screw nut screwed to the ball screw shaft via the plurality of balls; In a ball screw comprising a ball screw seal attached to both ends of the ball screw nut,
A foreign matter removing member having a hole corresponding to a cross-sectional shape perpendicular to the axis of the ball screw shaft, and preventing foreign matter from entering the inside of the ball screw nut;
A hole corresponding to the cross-sectional shape perpendicular to the axis of the ball screw shaft, and a sealing member for holding the lubricant inside the ball screw nut,
The foreign matter removing member and the sealing member are overlapped with each other, and the inner periphery of each of them is in contact with the ball rolling surface and the outer peripheral surface of the ball screw shaft,
The sealing member is located on the inner side of the foreign matter removing member located on the outer side in the axial direction of the ball screw nut;
On the inner periphery of the foreign matter removing member, a spiral protrusion that is fitted to the ball rolling surface of the ball screw shaft is provided,
A foreign matter removing opening for scraping the foreign matter and discharging it to the outside of the ball screw nut is provided from an end surface of the foreign matter removing member facing the axially outer side of the ball screw nut to the middle of the foreign matter removing member. And ball screw.

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