TW202108915A - Contact seal suitable for unthreaded shaft, and ball screw - Google Patents

Abstract

A seal member which can improve sealability even when applied to a unthreaded shaft, and a ball screw are provided. In this ball screw 1, in which a male-type member 2 and a female-type member 3 are fitted together in the axial direction, a seal member 16, which is an annular member endless in the circumferential direction, comprises: a sliding layer 14 that is formed from a fabric impregnated with rubber and that comprises a hole 14a which enables communication with the inner peripheral surface of the female-type member 3 and a fitting surface 14b which has a protrusion 14c formed thereon capable of fitting with the male grooves 7 on the male-type member 2 when the male-type member 2 has been inserted into the hole 14a; and a holding layer 15 laminated on the surface of the sliding layer 14 opposite of the fitting surface 14b, wherein the direction of the fabric that exhibits stretchability coincides with the circumferential direction of the hole 14a.

Description

Adapt to the contact seal of the finished shaft and the ball screw

The invention relates to a contact seal and a ball screw adapted to a finished shaft used in various industrial machinery.

In the past, a ball screw cap (also called a "female member") was fitted into the outer periphery of a ball screw shaft with a male groove (also called a "male member") as a sealing material. The ring-shaped contact seal of the fitting surface of the protrusion fitted to the outer peripheral surface of the ball screw shaft (for example, Patent Document 1). The fitting surface of the sealing material of Patent Document 1 discloses that by forming a sliding layer composed of fibers impregnated with rubber, the sliding resistance when the ball screw shaft is fitted into the sealing material can be reduced.

The ball screw shaft system does not have male grooves formed at both ends, but it is still the so-called "finished" situation of the round rod. In the "finished" ball screw shaft (also known as the "finished shaft"), it is impossible to insert ordinary ring-shaped sealing materials. In contrast, a sealing material is disclosed in which a cut portion is formed at one position in the circumferential direction of the ring, and the cut portion is opened to insert a ball screw shaft (for example, Patent Document 2). The sealing material of Patent Document 2 discloses that since the cut portion becomes V-shaped or arc-shaped in the axial direction, deviation in the axial direction is difficult to occur. [Prior Patent Document] [Patent Literature]

[Patent Document 1] JP 2014-5865 A [Patent Document 2] JP 2013-100920 A

[The problem to be solved by the invention]

However, in the case of Patent Document 2, it is unavoidable that foreign matter enters from the cut portion of the sealing material inserted into the ball screw shaft, and there is a problem that the sealing performance is reduced. In addition, in the case of Patent Document 1, since the sealing material extends in the radial direction, it is possible to insert the finished shaft, but because it extends in the radial direction, plastic deformation occurs in the direction in which the inner diameter of the mating surface becomes larger. A gap is generated between the fitting surface and the male groove, and good sealing performance cannot be obtained.

The purpose of the present invention is to provide a sealing material and a ball screw that can improve sealing performance even when applied to a finished shaft. [Means to solve the problem]

The sealing material of the present invention is a sealing material used for a ball screw in which a male member and a female member are fitted in the axial direction. The member has an inner peripheral surface of a plurality of female grooves where the ball can roll opposite to the male groove, and forms a circulation path in which the ball can circulate. The sealing material has: a hole that can be connected to the female groove. The inner peripheral surface of the component is connected; the sliding layer has a mating surface formed with a convex part that can fit the male groove of the male component when the male component is inserted into the hole, and is made of impregnated rubber The cloth is constituted; and the holding layer is laminated on the surface of the sliding layer opposite to the fitting surface; the direction indicating the stretchability of the cloth is consistent with the circumferential direction of the hole.

The ball screw system of the present invention includes: a male member formed on the outer peripheral surface with a plurality of male grooves through which the ball can roll; a female member having a plurality of female grooves on which the ball can roll opposite to the male groove. The inner peripheral surface, and forms the circulation path through which the balls can circulate; and the sealing material is arranged at one end or/and the other end of the female member in the axial direction; the male member and the female member are on the axis To be fitted, the ball screw system: The sealing material is an endless annular member in the circumferential direction, and has: a hole that can communicate with the inner peripheral surface of the female member; a sliding layer is formed on the When the male member is inserted into the hole, the mating surface of the convex part that can be fitted into the male groove of the male member is composed of cloth impregnated with rubber; and the holding layer is laminated on the sliding The surface of the layer opposite to the fitting surface; the direction indicating the stretchability of the cloth coincides with the circumferential direction of the hole. [Effects of Invention]

According to the present invention, since the sealing material is arranged such that the direction of the stretchability of the cloth coincides with the circumferential direction of the hole, after being inserted into the male member, it will be elastically deformed inwardly in the diameter direction, and the original shape will be restored. shape. That is, there is no gap between the fitting surface of the sealing material and the male member, and since the intrusion of foreign matter can be prevented, the sealing performance can also be improved when it is applied to a finished shaft.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. (Overall composition) As shown in FIG. 1A and FIG. 1B, the ball screw 1 includes a male member 2 and a female member 3. The male member 2 has: a screw shaft 21, a finished shaft composed of a rod-shaped metal member, and a plurality of spiral male grooves 7 formed on the outer peripheral surface; and a shaft end 22, which is not formed in The outer peripheral surface of the male groove 7 provided at both ends of the screw shaft portion 21 is formed. The shaft end 22 is in the shape of a round rod in which the male groove 7 is not formed, and is formed with the same outer diameter as the peak diameter of the peak between the male groove 7 and the male groove 7.

The female member 3 is made of metal and has a cylindrical cylindrical portion 8 and a plate-shaped plate portion 9 formed at one end of the cylindrical portion 8. The cylindrical portion 8 and the plate-shaped portion 9 are integrally formed. The plate-shaped portion 9 has an inner circumferential surface 11 communicating with the inner circumferential surface 10 of the cylindrical portion 8. A plurality of female grooves 12 are formed on the inner peripheral surfaces 10 and 11 of the cylindrical portion 8 and the plate-shaped portion 9 respectively. Each female groove 12 is formed in a spiral shape like the male groove 7 and is formed at a position facing the male groove 7 of the male member 2.

Inside the cylindrical portion 8, a circulation path 13 in which a plurality of balls B can circulate is formed. Between the male groove 7 and the female groove 12, a track P that can communicate with the circulation path 13 is formed. In this track P, a plurality of balls B are filled.

The ball screw 1 of this embodiment constitutes an infinite circulation path, and the ball B circulates repeatedly. The infinite circulation path is when the male member 2 and the female member 3 rotate relative to each other, the ball B advances while rolling in the track P. And go back to the original position through the circulation path 13. By the circulation of the balls B, the male member 2 and the female member 3 move relatively in the direction of the central axis A and can be fitted with each other. In addition, the male groove 7 of the present embodiment has a so-called four-thread structure in which the number of the male grooves is four, and the four circulation paths 13 are formed in accordance with the number.

At both ends of the female member 3 in the direction of the central axis A, a cover member 4 and a contact seal (hereinafter referred to as "sealing material") 16 for the adapted shaft covered by the cover member 4 are arranged. In addition, in FIG. 1B, the cover member 4 and the sealing material 16 which are composed of a pair and do not need to be specifically described differently are for simplification of the drawing, and only one cover member 4 and the sealing material 16 (the sealing material on the left side of the paper) 16) The codes of each part are added, and the other cover member 4 and the sealing material 16 (the cover member 4 and the sealing material 16 on the right side of the paper) may be omitted as appropriate, and this is notified in advance.

As shown in FIG. 2, the sealing material 16 is an endless ring-shaped member in the circumferential direction (the arrow C direction in FIG. 2 ), and includes a sliding layer 14 and a holding layer 15. The sealing material 16 is formed integrally in the circumferential direction, and is different from that in which the ends in the circumferential direction are bonded to each other with an adhesive or the like. The sliding layer 14 is a cylindrical layer surrounding the hole 14a. The hole 14a communicates with the inner peripheral surfaces 10, 11 of the female member 3 (FIG. 1B).

As shown in FIG. 3, the sliding layer 14 is formed continuously from one end to the other end of the sealing material 16 in the direction of the central axis A of the hole 14a, and has a fitting surface 14b provided at a position surrounding the hole 14a. On the fitting surface 14b, a convex portion 14c is formed. This convex portion 14c is a part that can be fitted into the male groove 7 of the male member 2 when the male member 2 is inserted into the hole 14a.

The sliding layer 14 has: a cloth, which is made of fibers (warp and weft) composed of more than one fiber including aramid fiber, nylon, urethane, cotton, silk, hemp, acetic acid, rayon, and fluorine, Then the thread is regularly shaped; and the rubber is impregnated on the cloth.

The cloth is a woven fabric composed of warp and weft, and uses plain weave, satin weave, and twill weave. The fabric is stretchable in one direction. When the surface of the cloth is regarded as the XY plane, the cloth system has stretchability only in the X direction, and the cloth system does not have stretchability in the Y direction orthogonal to the X direction. In order to have stretchability in the X direction, the weft yarn extending in the X direction may use, for example, a crimp yarn processed in a wool-like manner, and a twill weave or a satin weave is preferable. In this case, when the cloth is in the state of a fabric roll, the elongation in the X direction is 100% or more when the tensile load is 40N, and the elongation in the Y direction is preferably 10% or less. The sliding layer 14 is formed so that the direction indicating the stretchability of the cloth coincides with the circumferential direction of the hole 14a. That is, the X direction indicating the stretchability of the cloth in the sliding layer 14 coincides with the circumferential direction C (FIG. 2) of the hole 14a. The elongation of the cloth in this patent specification means the elongation of the cloth when a tensile load of 40N is applied to a cloth with a length in the X and Y directions of 15 mm.

The rubber system may be any one that can impregnate the cloth. As this rubber, for example, urethane rubber, nitrile rubber, silicon rubber, fluororubber, acrylic rubber, ethylene propylene rubber, butyl rubber, isoprene rubber, polyvinyl chloride rubber, and epoxy chloride can be used alone. Propyl alcohol rubber, hydrogenated nitrile rubber, chloroprene rubber, polybutadiene rubber, styrene butadiene rubber, natural rubber, etc., or those that have undergone various modifications of these rubbers. These rubber systems can be used alone, or a mixture of a plurality of rubbers can also be used. In addition, in addition to mixing a vulcanizing agent, rubber is a compounding agent that has been used conventionally as rubber compounding agents, such as vulcanizing accelerators, anti-aging agents, softeners, plasticizers, fillers, and coloring agents. In addition to these, in order to improve the lubricity of the sliding layer 14, solid lubricants such as graphite, silicone oil, fluorine powder, or molybdenum disulfide may be contained in the rubber.

The impregnation treatment of the cloth with the rubber mentioned above is suitable to use a method of impregnating a predetermined cloth after dissolving the rubber with a solvent or the like to make it into a liquid state. The cloth is impregnated with rubber, whereby the rubber material enters between the threads, and the threads are bonded together to be integrated, which can serve as the sliding layer 14. In addition, by impregnating the wires with rubber or the like, the abrasion resistance according to the friction between the wires is reduced, and furthermore, the abrasion resistance of the surface of the sliding layer 14 occurring between the sliding layer 14 and the male member 2 can be improved. Compared with those made of only fibers (short fibers or long fibers), the cloth is easy to handle because it is sheet-like, so it is easy to impregnate with rubber.

The holding layer 15 can be used alone, for example, urethane rubber, nitrile rubber, silicone rubber, fluororubber, acrylic rubber, ethylene propylene rubber, butyl rubber, isoprene rubber, polyvinyl chloride rubber, epichlorohydrin Alcohol rubber, hydrogenated nitrile rubber, chloroprene rubber, polybutadiene rubber, styrene butadiene rubber, natural rubber, etc., or those that have undergone various modifications of these rubbers. These rubber systems can be used alone, or a mixture of a plurality of rubbers can also be used. In addition, in addition to mixing a vulcanizing agent, rubber is a compounding agent that has been used conventionally as rubber compounding agents, such as vulcanizing accelerators, anti-aging agents, softeners, plasticizers, fillers, and coloring agents.

The holding layer 15 is a cylindrical layer laminated on the surface 14d of the sliding layer 14 on the side opposite to the side where the fitting surface 14b is formed (FIG. 3 ). The support ring can also be installed on the outer periphery of the holding layer 15. In this case, by applying internal pressure to the fitting surface 14b, the sealing performance can be improved. The support ring is a structure that applies internal pressure to the fitting surface 14b such as an O-ring, an endless belt spring, etc., and it is better to select a type that generates an appropriate amount of internal pressure according to a balance with sliding properties.

The sealing material 16 configured as described above preferably has a tightness of 0 or more on the fitting surface 14b in contact with the outer peripheral surface of the male member 2. In addition, "tightness" generally refers to the case where the shaft is larger than the diameter of the hole, which means the difference between the diameters of the two. In this patent specification, "tightness" is determined based on the inner diameter of the fitting surface 14b of the sealing material 16 after inserting the sealing material 16 into the shaft end 22 having a diameter 18% larger than the inner diameter of the fitting surface 14b The value obtained. When the outer peripheral surface of the male member 2, that is, the outer diameter of the shaft end 22 is regarded as D, and the inner diameter of the fitting surface 14b of the sealing material 16 is regarded as d1, the tightness (D-d1) is 0 or more. In addition, the upper limit of the tightness is preferably set so that the sliding resistance to the sealing material 16 of the male member 2 does not unexpectedly become too large.

The cover member 4 (FIG. 1B) is made of, for example, plastic or metal, and has: a cylindrical portion 4a, which is composed of a cylindrical member; a circular plate portion 4b, which is provided at one end of the cylindrical portion 4a; and a convex The edge part 4c is provided at the other end of the cylindrical part 4a. The cylindrical portion 4a, the circular plate portion 4b, and the flange portion 4c are integrally formed. The cylindrical portion 4a is in contact with the surface 15b of the holding layer 15 on the side opposite to the surface 15a on which the sliding layer 14 is formed. The disc portion 4b is formed to cover the surface 15d of the holding layer 15 on the side opposite to the surface 15c on which the female member 3 is formed, and has a through hole through which the male member 2 penetrates in the center. The flange portion 4c protrudes in the radial direction from the other end of the cylindrical portion 4a, and is formed to contact the female member 3. The cover member 4 is attached to both ends of the female member 3 in the direction of the central axis A, and the flange portion 4c is fixed to the end of the female member 3 in the direction of the central axis A using a locking member (not shown), thereby , The sealing material 16 can be installed.

The shape of the cover member 4 is not limited to this shape as long as it can be attached to the end of the female member 3 in the direction of the central axis A. For example, a recess can also be provided at the end of the female member 3 in the direction of the central axis A, and the sliding layer 14 and the holding layer 15 can be installed in this part to make a circular plate with a through hole through which the male member 2 penetrates. The cover member 4 is adhered to the side surface of the holding layer 15, and then a locking member (not shown) is used to install at least one of the two ends of the female member 3 in the direction of the central axis A.

In addition, the adhesive system for bonding the sealing material 16 to the cover member 4 includes, for example, an acrylic resin adhesive, an olefin adhesive, a urethane resin adhesive, and an ethylene-vinyl acetate resin adhesive. Adhesive, epoxy resin adhesive, chlorinated vinyl resin adhesive, chloroprene rubber adhesive, cyanoacrylic adhesive, silicon adhesive, styrene butadiene rubber Adhesives, nitrile adhesives, high temperature melting adhesives, phenol resin adhesives, melamine resin adhesives, urea resin adhesives, resorcinol adhesives, etc., and will The adhesive is set to a state of being heated and melted, and after it has been given fluidity, it is coated and cooled to harden and adhere, or the adhesive is hardened and adhered by heating Wait. The bonding surface is, for example, the contact surface 15b between the cylindrical portion 4a of the cover member 4 and the holding layer 15, or the contact surface 15d between the disc portion 4b and the holding layer 15, and the like.

In addition, as described above, a recess is provided at the end of the female member 3 in the direction of the central axis A, and the sealing material 16 is inserted in this part, and then from the outer circumference of the cylindrical portion 8 or the plate-like portion 9 of the female member 3 When a fixing screw (not shown) is driven into the holding layer 15 and fixed, the cover member 4 can be omitted. (Method of manufacturing sealing material)

An example of the manufacturing method of the sealing material 16 is demonstrated. First, a rod-shaped mold (not shown) having a screw shaft portion with a spiral male groove formed on the surface corresponding to the male member 2 is prepared. Rubber shrinks by vulcanization molding. In order to obtain the tightness of the vulcanized sealing material 16 of the mold system used in this embodiment, it is formed to have a predetermined size compared to the male member 2 to which the sealing material 16 is applied.

Next, a cloth impregnated with rubber or the like is wound around the outer peripheral surface of the mold so that the expansion and contraction direction coincides with the circumferential direction of the mold, thereby forming a precursor layer of the sliding layer 14. Then, the sheet-shaped rubber is wound on the outer peripheral surface of the precursor layer of the sliding layer 14 to form the precursor layer of the holding layer 15. Next, apply appropriate pressure to the outer peripheral surface of the precursor layer of the holding layer 15 to perform vulcanization molding, so that the sliding layer 14 and the precursor layers of the holding layer 15 become integrated, and the mating surface of the precursor layer of the sliding layer 14 is formed Convex 14c. Then, the respective precursor layers of the sliding layer 14 and the holding layer 15 are rotated in the circumferential direction of the mold and pulled out from the mold. Finally, the precursor layer integrated by the sliding layer 14 and the holding layer 15 is cut into a doughnut shape to obtain a sealing material 16 having a predetermined thickness. According to needs, an adhesive is used to adhere the cover member 4 to the sealing material 16. In the case where the cover member 4 is not required, the step of sticking the cover member 4 is unnecessary. (Function and effect)

The sealing material 16 is inserted into the male member 2 from the shaft end 22. At this time, when the inner diameter (hole inner diameter) of the convex portion 14c of the sealing material 16 is taken as d2, the sealing material 16 is forcibly enlarged to the outside in the diameter direction at least only the outer diameter D of the shaft end 22 and the seal The difference (D-d2) of the inner diameter d2 of the hole of the material 16. When reaching the screw shaft portion 21 through the shaft end portion 22, the sealing material 16 is elastically deformed inward in the diameter direction, and the convex portion 14 c enters the male groove 7. Since the sliding layer 14 is formed in such a manner that the direction of expansion and contraction of the cloth coincides with the circumferential direction of the hole 14a, the sealing material 16 is elastically deformed toward the inner side in the diameter direction to restore its original shape. In this case, the original shape is not limited to the case where the hole inner diameter d2 is exactly the same as before insertion. Insert a shaft with a diameter that is 18% larger than the inner diameter of the hole before insertion, and then remove it. After 1 day, the change in the inner diameter d2 of the hole is less than 1.0% (or less than 0.4mm) of the inner diameter of the hole before insertion Better. The sealing material 16 can be properly tightened when the change in the inner diameter d2 of the hole is less than 1.0% (or less than 0.4mm) of the inner diameter of the hole before insertion. After passing through the shaft end 22, the screw shaft 21 can be properly tightened. degree. That is, there is no gap between the fitting surface 14b of the sealing material 16 and the screw shaft portion 21, and since the intrusion of foreign matter can be prevented, the sealing performance can also be improved when it is applied to a finished shaft.

The sealing material 16 shrinks by vulcanization molding and becomes smaller than the mold used. However, in the case of this embodiment, in order to obtain a predetermined tightness of the sealing material 16 after vulcanization molding, a predetermined size is used Mold making. Therefore, since the sealing material 16 can obtain a predetermined tightness, the sliding resistance with the male member 2 can be reduced. In addition, because the mold is formed to shrink by only a larger amount than the male member 2, the cloth is easily deformed along the male groove 7. A cloth that does not stretch in the direction of the central axis A of the hole 14a can also be formed with The sealing material 16 in the shape of the male groove 7. Therefore, the sealing material 16 system can obtain good sealing performance, and can prevent the sliding resistance from increasing unexpectedly.

The sealing material 16 is formed by using a cloth impregnated with rubber to form a sliding layer 14 that fits into the male groove 7 of the male member 2, which can prevent fine foreign matter from intruding between the male member 2 and the female member 3, and reduce the male The sliding resistance when the profiled member 2 and the female profiled member 3 move in the direction of the central axis A relatively. In addition, by providing the sliding layer 14 in which cloth is impregnated with rubber, the wear resistance of the surface of the sliding layer 14 generated between the sliding layer 14 and the male member 2 can be improved. Furthermore, by laminating the retaining layer 15 on the surface 14d on the opposite side of the sliding layer 14 and the fitting surface 14b where the hole 14a is formed, the sealing material 16 can be stably attached to both ends of the female member 3. By attaching the sealing material 16 configured as described above to the female member 3, the male member 2 and the female member 3 can move relatively smoothly.

In addition, the mold has a complicated shape with a spiral male groove 7, but in the case of this embodiment, by using a cloth whose shrinkage direction is only one direction for the sliding layer 14, it is easy to predict the position of shrinkage or the amount of shrinkage. Therefore, the required mold can be easily produced.

On the other hand, when the shrinking direction of the cloth is the longitudinal and transverse directions, because the male groove 7 is curved and spiral, the shrinking direction of the sliding layer 14 after vulcanization will not be the same, and it can be accurately predicted The size of each part of the sliding layer 14 after vulcanization molding is difficult. Therefore, it can be said that more than a certain amount of trial and error is required to make a mold. With cloth that shows stretchability in both the vertical and horizontal directions, even if it is theoretically possible to obtain a sealing material 16 that is elastically deformed in the diameter direction, it is actually not possible to use that kind of cloth to make a sealing material 16 with a predetermined tightness. easy. (Modification)

The present invention is not limited to this embodiment, and can be appropriately changed within the scope of the gist of the present invention. For example, in the case of this embodiment, the case where the sealing material 16 is attached to both ends of the female member 3 is described, but the present invention is not limited to this, and the sealing material 16 may be used in accordance with the environment of use. Mounted on either end of the female member 3 in the direction of the central axis A.

In the case of this embodiment, it is explained that the male groove 7 of the male member 2 has a so-called four-thread structure, but the present invention is not limited to this, and the number of male grooves 7 can be adapted to the use of the ball screw The situation, change appropriately.

In the case of this embodiment, the case where the cloth applied to the sliding layer 14 is a woven cloth is described, but the present invention is not limited to this. As long as the shrinkage direction is only one direction, canvas, velvet, or denim may be used, for example.

In addition, after the shaft end 22 without the male groove 7 is shipped from the factory, the machine tool manufacturer or the like to which the ball screw 1 is to be delivered may be appropriately machined and processed into a predetermined shape. (Evaluation test)

In fact, the sealing material is produced and evaluated. The twill weave cloth used in the sliding layer of the sealing material is formed by impregnating NBR rubber. When the tensile load is taken as 40N, the stretchability of the cloth is indicated by the elongation in the X direction of 100%. The elongation in the Y direction is 7.3%. The holding layer is composed of NBR rubber, and the hardness of the NBR rubber is 60 as measured by the durometer hardness test (type A) according to JIS K6253. The sealing material has an inner diameter of 27.2 mm, an outer diameter of 43.9 mm, and a thickness of 15 mm. The sliding layer was arranged so that the X direction coincided with the circumferential direction of the hole 14a, and 10 sealing materials were produced.

Using the cylindrical insertion jig shown in Figure 4, insert the sample into one end of an iron rod with a diameter of 31.95mm. The insertion jig system includes: a cylindrical first jig 24; a cylindrical second jig 25, which is inserted into the first jig 24 from the outside. The first jig 24 is a solid truncated conical member, the outer diameter of the bottom surface is slightly larger than the outer diameter of the round bar 30, and a plurality of (3 in the case of FIG. 4) are evenly arranged on the outer peripheral surface in the center A guide protrusion 27 extending convexly in the axis A direction. The diameter of the virtual circle centered on the central axis A between the tips of the guide protrusions 27 connected to the bottom surface of the first jig 24 is 34 mm. The second jig 25 has a through hole 28 which has an inner diameter slightly larger than the outer diameter of the first jig 24, and the inner peripheral surface of the through hole 28 is formed with a projection corresponding to the guide 27 position and size of the guide groove 29.

First, insert the first jig 24 from the tip end into the upper end of the round bar 30. On the upper end side of the round bar 30, an edge portion (not shown) is formed. The first jig 24 is attached to the tip end in contact with the edge portion. The position stops. Next, the tip end of the sealing material 16 is directed toward the base end of the first jig 24, and the sealing material 16 is inserted into the first jig 24. Then, the tip end of the second jig 25 is brought into contact with the base end of the sealing material 16, and the base end of the second jig 25 is pushed toward the round bar 30. The pushed sealing material 16 is deformed to the outside in the diameter direction by the guide protrusion 27, and the hole 14a is enlarged in diameter, whereby the round rod 30 is inserted into the round bar 30 through the first jig 24. The second jig 25 is moved along the guide protrusion 27 by the guide groove 29, and the first jig 24 is inserted from the outside. The sealing material 16 inserted in the round rod 30 is removed from the round rod 30 immediately after insertion, and the inside diameter and outside diameter of the removed sealing material 16 are measured to confirm the difference between the inside diameter and outside diameter caused by the passage of time The amount of change.

For comparison, a sealing material (Comparative Example 1) in which a sliding layer was arranged such that the X direction parallel to the weft thread coincides with the direction of the central axis A of the hole 14a and a sealing material without a sliding layer (Comparative Example 2) were produced. In Comparative Examples 1 and 2, except for the above-mentioned differences, they were tested under the same conditions as the Examples to confirm the amount of change in the inner diameter and outer diameter caused by the passage of time.

Fig. 5A and Fig. 5B show the measurement results of the embodiment. In Fig. 5A, the horizontal axis is the elapsed time (days) after removal, and the vertical axis is the change in outer diameter (mm). In Fig. 5B, the horizontal axis is the elapsed time (days) after removal, and the vertical axis is the change in inner diameter (mm). From Fig. 5, after one day has passed, it can be confirmed that the amount of change in the outer diameter and inner diameter is 0.1 mm or less. In particular, the inner diameter is because the average value of the change is 0.03mm (0.1% of the hole inner diameter) after one day, and the change is almost 0 after 7 days, so it is reliably generated inward in the diameter direction. Elastic deformation, it can be said that the sealing material is almost restored to its original shape. From this fact, the sealing material of the embodiment shows that the direction of the stretchability of the cloth coincides with the circumferential direction of the aforementioned hole 14a, because it is forcibly expanded toward the outside in the diameter direction, and elasticity is surely generated toward the inside in the diameter direction. It is deformed to return to its original shape, so the tightness is within a predetermined range, and it is known that good sealing performance can be obtained.

Fig. 6A and Fig. 6B show the measurement results of the comparative example. In Fig. 6A, the horizontal axis is the elapsed time (minutes) after removal, and the vertical axis is the change in outer diameter (mm). In Fig. 6B, the horizontal axis is the elapsed time (minutes) after removal, and the vertical axis is the change in inner diameter (mm). The amount of change after 300 minutes has elapsed is 0.1 mm or more in Comparative Example 1 and 0.05 mm or less in Comparative Example 2. In addition, although not shown, it was confirmed that the amount of change in Comparative Example 1 was 0.1 mm or more even after 7 days. That is, in Comparative Example 1, in which the direction of stretchability of the cloth coincides with the axial direction of the hole, the amount of change in the outer diameter and inner diameter of the hole before insertion is large. On the other hand, since the sealing material that does not have a sliding layer but only a holding layer is made of rubber, it is restored to its original shape by elastic deformation. From this matter, the plastic deformation of the sealing material is caused by the cloth in the sliding layer, and it can be said that the plastic deformation of the cloth prevents the sealing material from returning to its original shape. In addition, since Comparative Example 2 has a sliding layer, the sliding resistance becomes high.

From the above, by aligning the direction of the stretchability of the cloth in the sliding layer with the circumferential direction of the hole, the tightness of the hole can be elastically deformed to the inside of the diameter direction, and it can also be improved when it is applied to the finished shaft. Tightness.

1: Ball screw 2: Male component 3: Female component 7: Sun slot 10, 11: each inner peripheral surface 12: Yin groove 14: Sliding layer 14a: hole 14b: Mating surface 14c: Convex 15: Holding layer 16: Sealing material

Fig. 1 is a schematic diagram showing the ball screw of the present embodiment, Fig. 1A is a perspective view, and Fig. 1B is a cross-sectional view. [FIG. 2] It is a perspective view of the sealing material of this embodiment. Fig. 3 is a partial end view showing the sealing material and the male member of the present embodiment. [Figure 4] is a perspective view for the explanation of the evaluation test. [Fig. 5] is a graph showing the results of the evaluation test of the embodiment, Fig. 5A is the evaluation result of the outer diameter, and Fig. 5B is the evaluation result of the inner diameter. [Fig. 6] is a graph showing the results of the evaluation test of the comparative example, Fig. 6A is the evaluation result of the outer diameter, and Fig. 6B is the evaluation result of the inner diameter.

1: Ball screw

2: Male component

3: Female component

4: cover member

4a: cylindrical part

4b: Disc section

4c: Flange

7: Sun slot

8: Cylindrical part

9: Plate part

10, 11: each inner peripheral surface

12: Yin groove

14: Sliding layer

14a: hole

14b: Mating surface

14c: Convex

14d: noodles

15: Holding layer

15a, 15b, 15c, 15d: surface

16: Sealing material

21: Screw shaft

22: Shaft end

A: Central axis

P: Orbit

B: Ball

Claims (4)

A sealing material is a sealing material used by a ball screw in which a male member and a female member are fitted in the axial direction. The male member is formed with a plurality of male grooves on the outer peripheral surface where the ball can roll, and the female member is The inner peripheral surface of a plurality of female grooves in which the ball can roll is formed opposite to the male groove, and a circulation path in which the ball can circulate is formed, and the sealing material is: have: The hole can be communicated with the inner peripheral surface of the female member; The sliding layer has a fitting surface formed with a convex portion that can fit into the male groove of the male member when the male member is inserted into the hole, and is composed of a cloth impregnated with rubber; and The holding layer is laminated on the surface of the sliding layer opposite to the mating surface; The direction indicating the stretchability of the cloth coincides with the circumferential direction of the hole. For example, the sealing material of item 1 of the scope of patent application, inserting a round rod with an outer diameter 18% larger than the inner diameter of the hole, removing from the round rod and inserting a pair of the inner diameter after one day into the round rod The previous change in the inner diameter was less than 1.0% of the inner diameter before insertion. A ball screw includes: a male member forming a plurality of male grooves on the outer peripheral surface where the ball can roll; a female member having a plurality of female grooves formed opposite to the male groove in which the ball can roll The peripheral surface, and forms the circulation path through which the balls can circulate; and the sealing material is arranged at one end or/and the other end of the female member in the axial direction; the male member and the female member are in the axial direction Is fitted, the ball screw system: The sealing material is an endless ring-shaped member in the circumferential direction, and has: The hole can be communicated with the inner peripheral surface of the female member; The sliding layer has a fitting surface formed with a convex portion that can fit into the male groove of the male member when the male member is inserted into the hole, and is composed of a cloth impregnated with rubber; and The holding layer is laminated on the surface of the sliding layer opposite to the mating surface; The direction indicating the stretchability of the cloth coincides with the circumferential direction of the hole. For example, the ball screw of the third item of the scope of patent application, in which a round rod with an outer diameter 5mm larger than the inner diameter of the hole is inserted, and the pair of inner diameters after one day is removed from the round rod and before the inner diameter pair is inserted into the round rod The amount of change in the inner diameter is less than 1.0% of the inner diameter before insertion.

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