JP2008309173A - Ball screw sealing device and ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball screw sealing device having improved installing efficiency of the sealing device while preventing damage to a seal member and the degradation of sealing performance due to the one-sided contact of a lip portion or the like, and to provide a ball screw. <P>SOLUTION: The sealing device 10 comprises an annular seal member 12 provided at the end of a nut 3 and having the lip portion 14 for slide-contacting the outer peripheral face of a screw shaft 2, and an annular face plate 16 for fixing the seal member 12 to the end of the nut 3. The face plate 16 is mounted at the end of the nut 3 to cover the seal member 12 at the axial outside for holding the seal member 12 between itself and the end of the nut 3 while making the face opposite to the end of the nut 3 directly abut on the nut 3, to constrain the movement of the seal member 12 in the axial, peripheral and radial directions at the same time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ball screw sealing device and a ball screw including the same.

  The ball screw includes a screw shaft having a helical thread groove on the outer peripheral surface, a nut having a spiral screw groove facing the screw groove of the screw shaft on the inner peripheral surface, and the screw shaft and the screw grooves of the nuts. And a plurality of rolling elements interposed between them so that the nut or the screw shaft is moved in the axial direction by rotating the screw shaft or the nut. Generally, this type of ball screw includes a ring-shaped seal member having a lip portion that is in sliding contact with the outer peripheral surface of the screw shaft, and a fixing device that fixes the seal member to the nut end portion. The seal member of this type is formed so that the shape of the lip portion approximates the cross section of the screw shaft, and the phase of the thread groove and the phase of the seal member are complementarily fitted together. This prevents the intrusion of foreign matter into the ball screw and the leakage of the lubricant from the ball screw to the outside.

  Here, in the conventional ball screw sealing device, as a fixing method of the seal member, if the thickness of the seal member in the axial direction exceeds, for example, one lead of the screw shaft, After adjusting the position in the circumferential direction of the seal (hereinafter also referred to as “phase”) as in the technique described in Patent Document 1, a tap hole that leads from the outer diameter portion of the nut to the outer diameter portion of the seal member is formed. A method is used in which the seal member is screwed to the end of the nut using the tapped holes.

In addition, if the axial thickness of the seal member is thin, for example, one lead or less of the screw shaft, an annular fixing member (hereinafter also referred to as a face plate) as in the technique described in Patent Document 2, for example. ), A method of fastening the seal member together with the face plate by inserting a bolt or the like from the axial direction into the fixing hole provided in the face plate and the fixing hole provided in the seal member, and the phase of the seal member There is an example in which the fixing hole provided in the seal member is a long hole.
Japanese Utility Model Publication No. 02-091253 Japanese Utility Model Publication No. 02-071156 Japanese Patent Laid-Open No. 01-172676 JP 2000-179640 A

  However, in the technique described in Patent Document 1, a tap hole that communicates in the radial direction is provided from the outer diameter portion of the nut to the outer diameter portion of the seal member, and the seal member is screwed to the nut end portion. Adjust the position (phase) in the circumferential direction where the lip part of the seal member and the outer peripheral surface of the screw shaft are in sliding contact with each other, and then attach a bolt hole for screwing to the outer diameter part of the seal member Must be processed. Therefore, there is a problem that the cost is increased due to an increase in the process of the current machining, and the cutting powder during the current machining adheres to the screw shaft.

  Furthermore, normally, when the ball screw is used in a horizontal position, the outer peripheral surface of the seal member becomes an open portion existing at the lowest part of the nut, and particularly in oil lubrication, oil leakage on the outer peripheral surface of the seal member should be prevented. It is possible to increase the amount of residual oil in the nut, but the sealing member mounting method disclosed in Patent Document 1 cannot prevent leakage of oil or grease from the outer peripheral surface of the sealing member, This can cause deterioration of the lubrication state.

  In the technique described in Patent Document 2, the fixing hole provided in the seal member and the fixing hole provided in the face plate are fastened together with a seal seat surface formed on the nut by a bolt for fixing the seal. Therefore, in managing the position (phase) in the circumferential direction in which the lip portion of the seal member is in sliding contact with the outer peripheral surface of the screw shaft, the circumferential direction of the tap hole for the bolt processed in the seal seat surface And the relative phase between the axial position of the seal seat and the phase of the thread groove must be strictly managed.

In other words, the processing error of the axial position of the seal seat surface is Δx (mm), the lead of the ball screw is L (mm), and the error between the ideal screw groove phase and the seal member phase is Δα ( deg), these relationships are expressed by the following equation 1.
Δα = Δx / L * 360 (Formula 1)
Therefore, for example, in the case of a ball screw having a lead of 5 mm, when the axial position of the seal seat surface has a processing error of 0.1 mm in the axial direction with respect to the normal position, a relative of 7.2 (deg) A phase shift will occur. However, in general, managing the axial position of the seal member with a high accuracy of 0.1 mm or more with respect to the phase of the thread groove is difficult because the seal member is soft and the accuracy of the contact is poor. It is difficult to manage. For this reason, as disclosed in Patent Document 3, for example, in a method in which an arc-shaped hole formed in a seal member and a hole provided in a face plate are fastened together with a fixing bolt, the seal member is not processed due to a processing error of a nut. It is difficult to absorb the error between the phase and the phase of the thread groove, which causes a deterioration in the sealing performance due to the contact of the lip portion of the sealing member.

  On the other hand, for example, in the technique described in Patent Literature 4, although the hole formed in the seal member is made into a long hole so that the phase of the seal member can be adjusted, the back and front of the seal member can be freely arranged on both ends of the nut. In order to attach, in practice, there is a problem that a large number of long holes in the seal member must be provided. Further, if the nut length and the nut outer diameter are slightly different, it is difficult to use the seal member in common, resulting in an increase in cost.

  Therefore, the present invention has been made paying attention to such problems, and improves the assembly efficiency of the seal device and prevents damage to the seal member and deterioration of the sealability due to contact with the lip portion. An object of the present invention is to provide a ball screw sealing device and a ball screw.

  In order to solve the above-mentioned problems, a first invention of the present invention is a screw shaft having a helical thread groove on an outer peripheral surface, and an inner peripheral surface having a helical thread groove facing the screw groove of the screw shaft. And a plurality of rolling elements interposed between the threaded shaft and the thread grooves of the nut so as to be freely rollable, and provided at the end of the nut. An annular sealing member that is in sliding contact with the outer peripheral surface of the shaft, and an annular fixing member for fixing the sealing member to the nut end, wherein the fixing member is The nut end is attached to the nut end so as to cover the seal member from the outside in the axial direction, and the outer peripheral portion of the annular surface facing the nut end is brought into direct contact with the surface on the nut side. The inner peripheral part of the annular surface facing the part and the nut By sandwiching the seal member between the parts, the axial direction of the seal member, it is characterized in that is adapted to restrain movement of the circumferential and radial directions simultaneously. In order to hold the seal member between the fixing member itself and the nut end portion and restrain the seal member, for example, a certain fixed state is maintained by utilizing elastic deformation of a part or the whole of the seal member. can do.

  According to the ball screw sealing device according to the first aspect of the invention, the fixing member is attached to the nut end so as to cover the seal member from the outside in the axial direction, and the surface facing the nut end is directly applied to the nut. The seal member is clamped between itself and the end of the nut while being in contact with the seal member, so that the seal member is restrained in the circumferential direction of the seal member such as a fixing hole. The seal member can be fixed without providing a shape that limits the position of the seal member. Therefore, when the seal member is fixed to the nut, the circumferential position of the seal member can be arbitrarily determined. Therefore, the assembly efficiency of the sealing device is significantly improved. The phase of the seal member can be adjusted in accordance with the phase of the thread groove. For this reason, damage to the seal member and deterioration of the sealing performance due to one-piece contact or the like are prevented.

  Here, in the ball screw sealing device according to the first aspect of the present invention, it is preferable that a portion of the fixing member sandwiching the sealing member between the nut end portion is an uneven surface. With such a configuration, when the sealing member is clamped between the fixing member itself and the nut end, when the sealing member is restrained, a part or the whole of the sealing member is formed on the uneven surface of the fixing member. Elastic deformation can be used more effectively. Therefore, a more reliable fixed state can be maintained.

  The sealing member applied to the ball screw sealing device according to the first invention may be a thick member exceeding one lead of the screw shaft or a thin member having one lead or less. The shape of the ball screw sealing device according to the first invention is not limited as long as it can be incorporated in the nut and can be clamped in the axial direction by a fixing member. It is preferable that the shape is approximate to the cross section of the screw shaft and the thickness in the axial direction is less than or equal to one lead of the screw shaft. With such a configuration, even if the seal member is slightly elastically deformed in the thickness direction by the amount of tightening due to being clamped from the axial direction by the fixing member, the shape of the lip portion is in the cross section of the screw shaft. By approximating and applying to a thin seal whose axial thickness is less than one lead of the screw shaft, the degree of change in shape in the axial direction becomes relatively small, The effect of preventing the sealing member from being damaged or the sealing performance from being deteriorated due to the above or the like is more effectively exhibited.

  The second invention of the present invention is a screw shaft having a spiral thread groove on the outer peripheral surface, a nut having a spiral thread groove facing the screw groove of the screw shaft on the inner peripheral surface, A plurality of rolling elements interposed between the screw groove of the screw shaft and the screw groove of the nut so as to freely roll, and a lip portion which is provided at the end of the nut and slidably contacts the outer peripheral surface of the screw shaft. An annular sealing member and a sealing device having an annular fixing member for fixing the sealing member to the nut end, and the ball screw according to the first invention as the sealing device It is characterized in that a sealing device is mounted.

  According to the ball screw according to the second invention, since the ball screw sealing device according to the first invention is mounted as the sealing device, for example, in the circumferential direction of the sealing member such as a fixing hole. The seal member can be fixed without providing a shape that defines the position, and the position of the seal member in the circumferential direction is also determined by adjusting the position of the seal member in the circumferential direction according to the position of the thread groove. it can. Therefore, it is possible to improve the assembly efficiency of the seal device and prevent damage to the seal member and deterioration of the sealing performance due to the lip portion per piece.

  As described above, according to the present invention, there is provided a ball screw seal device and a ball screw that can improve the assembly efficiency of the seal device and can prevent damage to the seal member and deterioration of the sealing performance due to contact of the lip portion. Can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is a perspective view showing an embodiment of a ball screw according to the present invention.
As shown in FIG. 1, the ball screw 1 includes a screw shaft 2 having a helical thread groove 2a on the outer peripheral surface, and a spiral screw groove 3a facing the screw groove 2a of the screw shaft 2 on the inner peripheral surface. And a plurality of balls 4 interposed in a spiral ball rolling path 6 formed by both screw grooves 2a and 3a so as to be freely rollable.

  The ball screw 1 has a nut 3 formed with a flat surface 8 having a part of its outer peripheral surface cut in parallel and flat in the axial direction, and is bent in a substantially U shape on the flat surface 8. The return tube 7 is fixed by a tube presser (not shown). The nut 3 is provided with a pair of through holes 9 that open to the flat surface 8 and communicate with the thread groove 3a of the nut 3. Both ends of the return tube 7 are connected to the through holes 9 on the flat surface 8 side. Has been inserted from.

  The ball 4 rolling in the ball rolling path 6 is circulated through the return tube 7. That is, the loaded balls 4 move in the ball rolling path 6 and turn around the screw shaft 2 a plurality of times before the end points of the ball rolling path 6 (return tube 7 and ball rolling path 6 and At one of the ends (opening portion) of the return tube 7. The scooped up ball 4 passes through the return tube 7 and is returned to the starting point of the ball rolling path 6 from the other end (opening) of the return tube 7. Thereby, when the nut 3 and the screw shaft 2 screwed to the screw shaft 2 through the ball 4 are relatively rotated, the screw shaft 2 and the nut 3 are axially moved through the rolling of the ball 4. Since the ball 4 that moves relative to each other and rolls in the ball rolling path 6 is infinitely circulated by the return tube 7 that connects the starting point and the end point of the ball rolling path 6, the screw shaft 2 And the nut 3 can continuously move relative to each other.

  Here, at both ends of the nut 3 of the ball screw 1, seal devices 10 are mounted as shown in FIG. FIG. 2 is a view for explaining a sealing device attached to both ends of the nut. FIG. 2 (a) is a cross section including the axis of the nut 3. In FIG. The illustration of the ball 4 and the like is omitted. FIG. 2B is an enlarged view of a portion A in FIG.

Hereinafter, this sealing device will be described in more detail with reference to FIGS. 2 and 3 as appropriate. 3A and 3B are explanatory views of a fixing member constituting the sealing device. FIG. 3A is a front view thereof, FIG. 3B is a side view thereof, and FIG. 3C is an enlarged view of a portion B in FIG. FIG.
As shown in FIG. 2, the nut 3 of the ball screw 1 is fitted with sealing devices 10 at both ends thereof. The sealing device 10 includes a sealing member 12, a face plate 16, and a plurality of fixing bolts 20 for fixing the face plate 16 to the end of the nut 3. In addition, about the sealing device 10 of the left side of the figure, each component is shown in a disassembled state, and the sealing device 10 on the right side of the figure shows an assembled state.

  Specifically, the seal member 12 is an annular resin member, and on its inner peripheral surface, a lip portion 14 slidably contacting the screw groove 2a on the outer peripheral surface of the screw shaft 2 is complementary to the screw groove 2a. It is formed with a shape. The seal member 12 is of a thick type having a thickness exceeding the lead of the screw groove 2a1 of the screw shaft 2. Further, the sealing member 12 is not formed with a fixing hole as in the technique described in Patent Document 2, for example.

  On the other hand, the face plate 16 is a fixing member for fixing the seal member 12 to the end of the nut 3 and is formed in an annular shape by pressing from a steel plate. The diameter of the inner peripheral surface 16n of the annular face plate 16 is substantially the same as the diameter of the valley portion of the lip portion 14 of the seal member 12, and the diameter of the outer peripheral surface 16g The size is larger than the outer diameter 12g of the seal member 12 (see FIG. 2A) by an amount necessary for mounting the fixing bolt 20. As shown in FIG. 3, the face plate 16 is provided with four circular mounting holes 16a penetrating in the front and back directions on the outer peripheral portion of the annular surface. Each mounting hole 16a has an inner diameter capable of mounting the plurality of fixing bolts 20, and is formed slightly closer to the outer diameter side than the center in the radial direction of the face plate 16. The mounting holes 16a are formed at positions spaced apart at equal intervals in the circumferential direction of the face plate 16 (that is, equally spaced at 90 ° in this example).

  Further, the face plate 16 is formed with two adjustment holes 16t in the inner peripheral portion of the annular surface in two directions penetrating in the front and back directions. Each of the adjustment long holes 16t is formed at a position closer to the inner side in the radial direction than the mounting hole 16a opposed in the radial direction of the face plate 16 (in the same drawing (a), a position on the line XX). In addition, the direction of the long axis of the long hole is formed along the substantially circumferential direction of the face plate 16. Further, each adjustment slot 16t is formed by pressing as shown in the enlarged view of FIG. 10C, so that the side 16d by pressing and the opposite side 16k on the front and back surfaces are formed. However, the surface of the burr side 16k is attached to the end of the nut 3 as a pressing surface 16m facing the seal member 12.

  Further, as shown in FIG. 2, seal mounting step portions 32 each including an annular concave step portion are provided on both ends of the nut 3 coaxially with the nut 3. The inner diameter of the seal mounting step 32 is slightly larger than the outer diameter 12g of the seal member 12, and is provided so as to face the inner peripheral portion of the annular surface of the face plate 16. Yes. Further, the step depth 32d of the seal mounting step 32 is slightly shallower in the axial direction than the thickness 12t of the seal member 12 (symbol Δβ shown in FIG. 4B). Thus, when the seal member 12 is inserted into the end of the nut 3 from the outside in the axial direction with respect to the seal mounting step 32, the seal member 12 is fitted into a state protruding in the axial direction by the tightening allowance Δβ. It has become.

  Further, a face plate mounting step portion 36 formed of an annular concave step portion is provided coaxially with the nut 3 at a position outside the seal mounting step portion 32 in the axial direction at the end of the nut 3. The inner diameter 36n of the face plate mounting step 36 is slightly larger than the outer diameter 16g of the face plate 16, and is provided to face the outer peripheral portion of the annular surface of the face plate 16. . The bottom surface of the face plate mounting step 36 is a face plate seating surface 38 to which the face plate 16 is attached. The face plate seating surface 38 is located at a position facing the four mounting holes 16 a of the face plate 16. The tapped holes 40 that are screwed into the fixing bolt 20 are provided at four locations. Further, the depth 36d of the step of the face plate mounting step 36 is such that the face plate 16 is fitted into the face plate mounting step 36 and a plurality of fixing bolts 20 are attached (the right side sealing device 10 shown in FIG. The head of the fixing bolt 20 is formed to a depth that does not protrude from the end face 3t of the nut 3.

Next, a mounting method of the sealing device 10 having the above-described configuration will be described with reference to FIG. 4 as appropriate. FIG. 4 is a diagram (a) to (c) for explaining a method of mounting the sealing device according to the embodiment of the present invention, and each drawing shows one end of the nut in a cross section including its axis. Yes.
When the sealing device 10 is mounted on the end of the nut 3 of the ball screw 1, first, the screw shaft 2, the ball 4 and the return tube 7 are assembled into the nut 3 so that the ball screw 1 can be operated. . Next, the lip portion 14 of the seal member 12 is inserted from the shaft end so that the phase of the lip portion 14 of the seal member 12 is aligned with the screw groove 2a of the screw shaft 2 so as to follow the screw groove 2a of the screw shaft 2. The seal member 12 is moved to the end face of the nut 3 while rotating along the screw groove 2a on the shaft 2 (see FIG. 4A). At this time, the seal member 12 protrudes from the face plate seating surface 38 of the nut 3 by a fastening allowance Δβ (see FIG. 2B).

Next, the end of the nut 3 is moved to a position where the surface of the seal member 12 on the nut 3 side comes into contact with and closely contacts the seal seat surface 34 which is the bottom surface of the seal mounting step 32 formed at the end of the nut 3. The seal member 12 is inserted, and the circumferential position (phase) of the seal member 12 is provisionally determined at this position (see FIG. 4B).
Next, the face plate 16 is inserted into the screw shaft 2 at the end of the nut 3 so as to cover the seal member 12 from the outside in the axial direction. At this time, the direction of insertion of the face plate 16 is such that the portion sandwiching the seal member 12 between the end portions of the nut 3 faces the pressing surface 16m facing the seal member 12 on the burr side 16k by pressing. Attach to the end of the nut 3.

  Next, the surface 16m of the face plate 16 that faces the end of the nut 3 is placed on the outer face of the annular face 16m with respect to the face plate seating surface 38 of the face plate mounting step 36 formed on the nut 3. The seal member 12 is sandwiched between the inner peripheral portion of the annular surface 16m and the end portion (face plate seat surface 38) of the nut 3 while making direct contact (see FIG. 4C). Then, the fixing bolts 20 are respectively inserted into the four mounting holes 16 a formed in the outer peripheral portion of the surface 16 m of the face plate 16, and the four fixing bolts 20 are respectively connected to the tap holes 40 of the face plate seat surface 38 of the nut 3. The face plate 16 and the seal member 12 are temporarily fixed.

  Next, the screw shaft 2 is rotated, and the contact between the screw groove 2a and the lip portion 14 of the seal member 12 is confirmed. Then, at the time of confirming the hit, it is confirmed whether there is a piece hit or entanglement, and if there is a piece hit or entanglement, the adjustment long hole 16t of the face plate 16 is used to seal from the adjustment long hole 16t. The position of the member 12 in the circumferential direction is finely adjusted with an adjusting jig or the like so as to be an ideal position with respect to the screw shaft 2, thereby eliminating the contact with one piece or the entanglement.

  Finally, the face plate 16 is finally tightened to the face plate seating surface 38 of the nut 3 with a predetermined torque by using the four fixing bolts 20, whereby the seal member 12 sandwiched between the face plate 16 and the nut 3 is tightened. By tightening and compressing by a plurality of fixing bolts 20 by Δβ, movement of the seal member 12 is prevented by frictional force by elastic deformation of the tightening allowance Δβ, and the seal member 12 is moved in the axial direction, the circumferential direction, and the radial direction Are restrained at the same time. The tightening allowance Δβ is preferably about 0.05 mm to 0.2 mm.

Next, functions and effects of the sealing device 10 and the ball screw 1 will be described.
As described above, the ball screw 1 includes the sealing device 10 at both ends of the nut 3. According to the sealing device 10, the face plate 16 seals the end of the nut 3 from the outside in the axial direction. The inner surface of the annular surface 16m is mounted so as to cover the member 12 and the surface 16m facing the end of the nut 3 is brought into direct contact with the nut 3 at the outer periphery of the annular surface 16m. The seal member 12 is sandwiched between the end portion and the end of the nut 3, and the movement of the seal member 12 in the axial direction, the circumferential direction, and the radial direction is constrained at the same time. The seal member 12 can be fixed without providing a shape that limits the position (phase) in the circumferential direction of the fixing hole or the like. Therefore, when the seal member 12 is fixed to the nut 3, the circumferential position of the seal member 12 can be arbitrarily determined. Therefore, the assembly efficiency of the sealing device 10 is significantly improved. The phase of the seal member 12 in the circumferential direction can be adjusted in accordance with the position of the thread groove 2a. Therefore, it is possible to prevent the seal member 12 from being damaged and the sealing performance from being deteriorated due to a single contact.

  Further, the outer diameter 12g of the seal member 12 is smaller than the outer diameter of the nut 3 than the joint-type seal member exemplified in the above-described conventional example, and the incorporation into the nut is improved. As described above, the seal member 12 can be fixed without providing the seal member 12 with a shape that limits the position (phase) in the circumferential direction of the seal member 12 such as a fixing hole. When the nut is fixed to the nut 3, the circumferential position of the seal member 12 can be arbitrarily determined. For example, this is applicable to ball screws of other specifications having different axial lengths and outer diameters of the nut. The range of the specification which can mount | wear with the sealing apparatus 10 can be expanded. That is, common use is possible, versatility is improved, and costs can be reduced.

  According to the sealing device 10, as described in the mounting method described above, the screw shaft 2, the ball 4 and the return tube 7 are assembled in the nut 3 so that the ball screw 1 is operable, and then the sealing device is used. Since it is incorporated, the seal member 12 can be fixed by causing the lip portion 14 of the seal member 12 to follow the thread groove 2 a of the screw shaft 2. Therefore, it is possible to improve the assembly accuracy in the axial center, the direction orthogonal to the axis, and the phase direction.

Further, since the seal member 12 can be brought into close contact with the seal seat surface 34 of the nut 3 before being pressed and clamped by the face plate 16, the lip portion 14 of the seal member 12 is made to follow the screw groove 2a of the screw shaft 2. The state in which the ball screw 1 is used is the same as that of the ball screw 1 and the perpendicularity to the axis is good.
Furthermore, even if the face plate 16 is temporarily fixed to the face plate seating surface 38 of the nut 3 using the four fixing bolts 20, the seal member 12 itself does not have a shape that restricts movement in the circumferential direction thereof. It can rotate in the circumferential direction. Therefore, the fine adjustment work of the phase in the temporarily fixed state can be easily performed.

  Further, according to this sealing device 10, the face plate 16 has a pressing surface 16 m that faces the sealing member 12 at a portion of the sealing member 12 that sandwiches the sealing member 12 between the end portion of the nut 3. Is attached to the end of the nut 3, and the portion sandwiching the seal member 12 between the end of the nut 3 is an uneven surface, so that the face plate 16 and the end of the nut 3 When the sealing member 12 is clamped between them and the sealing member 12 is restrained, a more reliable fixed state can be maintained by utilizing the elastic deformation of the sealing member on the surface 16 k of the face plate 16.

  As described above, according to the sealing device 10 and the ball screw 1 of the ball screw 1, the position of the sealing member 12 in the circumferential direction can be arbitrarily determined when the sealing member 12 is fixed to the nut 3. Therefore, the assembling efficiency of the sealing device 10 is remarkably improved, and the sealing member 12 is not damaged or the sealing performance is not deteriorated due to the contact of the lip portion 14 or the like. Furthermore, since the sealing member 12 can be finally adjusted to the optimum position with respect to the position of the screw groove 2a of the screw shaft 2 by using the adjustment long hole 16t for fine phase adjustment, the lip portion 14 is allowed to come into contact with each other. It is possible to more reliably prevent the seal member 12 from being damaged and the sealing performance from being lowered.

The ball screw sealing device and the ball screw according to the present invention are not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the seal member 12 is described as an example of a thick type exceeding the thread groove 2a1 lead of the screw shaft 2. However, the present invention is not limited to this, and the seal member 12 can be built in the nut 3 such as a face plate. The shape is not limited as long as the fixing member can be clamped from the axial direction.

A specific modification is shown in FIG.
The first modification is different from the above embodiment in that the thickness of the seal member and the seal mounting step are formed shallow. That is, the seal member 12B in the first modification is a thin seal as shown in the figure, and the shape of the lip portion 14B approximates the cross section of the screw shaft 2 and the axial direction thereof. Is formed to be one lead or less of the screw shaft 2. Also, the seal mounting step 32B is formed shallow by a depth corresponding to the thickness of the seal member 12B formed thin, and the fastening allowance Δβ is ensured as in the above embodiment.

  With the configuration of the first modification, even if the seal member 12B is elastically deformed slightly in the thickness direction by the amount of the fastening allowance Δβ that is sandwiched from the axial direction by the face plate 16, the shape of the lip portion 14B Is a thin seal that approximates the cross section of the screw shaft 2 and whose axial thickness is less than or equal to one lead of the screw shaft 2, the degree of change in shape in the axial direction is the above embodiment. In contrast, the effect of preventing damage to the seal member 12B and deterioration of the sealing performance due to contact with each other is more effectively exhibited.

Further, for example, in the above-described embodiment, the phase of the seal member 12 is finely adjusted in addition to the mounting hole 16 a provided for fixing the face plate 16 to the nut 3 in order to sandwich and hold the seal member 12. However, the present invention is not limited to this, and the face plate 16 may not be provided with the adjustment long hole 16t.
In the case where the adjustment plate 16t is not provided with the adjustment hole 16t, when the seal member 12 is phase-adjusted by the method of mounting the sealing device 10, the seal protrudes radially inward from the inner diameter of the face plate 16. By moving the lip portion 14 of the member 12 directly in the circumferential direction, the circumferential position of the seal member 12 is finely adjusted so as to be an ideal position with respect to the screw shaft 2, thereby eliminating one-sided contact and entrainment. can do. However, this fine adjustment method using the portion protruding radially inward from the inner diameter of the face plate 16 is inferior in terms of workability compared to the case where the adjustment long hole 16t is used, so that the assembly work can be performed more efficiently. When performing, it is preferable to provide the adjustment plate 16t for adjusting the phase of the seal member 12 in the face plate 16.

  Further, for example, in the above-described embodiment, the face plate 16 has a portion where the seal member 12 is sandwiched between the end portion of the nut 3, and the surface on the burr side 16 k by pressing is used as a pressing surface 16 m facing the seal member 12. 3 is used as an uneven surface by sandwiching the seal member 12 between the end of the nut 3 and the end of the nut 3. In order to hold the seal member 12 and restrain the seal member 12 in the above description, an example has been described in which a more secure fixing state is maintained by using elastic deformation of the seal member on the surface 16k of the return side of the face plate 16. If it is the structure which hold | maintains the sealing member 12 with the frictional force by the clamping by clamping the sealing member 12 between the face plate 16 and the edge part of the nut 3, it will not be limited, but the part which clamps the sealing member 12 The without certain aspects uneven, for example, it may be a flat surface. However, in order to hold the sealing member 12 more securely by using the elastic deformation of the sealing member, it is preferable that the portion sandwiching the sealing member 12 between the end portions of the nut 3 is an uneven surface.

Furthermore, when the part which clamps the sealing member 12 between the ends of the nut 3 is an uneven surface, various structures can be adopted as the uneven surface.
Here, the specific modification of a face plate is shown in FIGS.
The face plate 16C of the second modified example shown in FIG. 6 has a knurling process 16e on the portion of the pressing surface 16m facing the seal member 12 where the face plate 16C contacts the seal member 12. The point is different from the above embodiment. In this example, the adjustment long hole 16t for phase adjustment is not formed.

Further, in the face plate 16D of the third modification shown in FIG. 7, an annular groove 16p is formed by machining in a portion of the pressing surface 16m facing the seal member 12 where the face plate 16D contacts the seal member 12. The point which forms is different from the said embodiment. Also in this example, the adjustment long hole 16t for phase adjustment is not formed.
Furthermore, the face plate 16F of the fourth modified example shown in FIG. 8 has a circular shape so that the face plate 16F contacts the seal member 12 and protrudes toward the pressing surface 16m facing the seal member 12. A difference from the above embodiment is that a plurality of (8 in this example) the emboss 16r is processed at equal intervals in the circumferential direction. Also in this example, the adjustment long hole 16t for phase adjustment is not formed.

  Even in the configurations of the second to fourth modified examples, the knurling process 16e, the annular groove 16p, and the plurality of embosses 16r are respectively provided in the portions that sandwich the seal member 12 between the end portions of the nut 3. Since the concave and convex portions are applied to make the concave and convex portions bite into the sealing member 12, the frictional force between the sealing member 12 and the face plate 16 is increased, and the axial direction, the circumferential direction and the radial direction of the sealing member 12 are increased. The restraint can be further ensured.

  In addition, about the uneven | corrugated shape formed in the face plate 16, although it will be easy if it forms by the press work in the said embodiment, for example, it is preferable to form the uneven | corrugated shape so that it may be as sharp as possible. Still further, in the press working in the above-described embodiment, it is desirable that the edge portion (edge side) of the surface 16k on the return side 16k of the adjustment long hole 16t is extruded in the axial direction by about 0.1 mm to 0.3 mm. Further, the protruding amount of the tightening allowance Δβ of the seal member 12 at this time is not limited to the above-described 0.05 mm to 0.2 mm, and may be a protruding amount smaller than that.

For example, in the above-described embodiment, the mounting holes 16a are formed in the face plate 16 at regular intervals in the circumferential direction of the face plate 16 (equal distribution at 90 ° in the example of the above-described embodiment). However, the present invention is not limited to this, and the plurality of mounting holes may not be equally arranged.
For example, in the face plate 16E of the fifth modified example shown in FIG. 9, the two mounting holes 16a on the left and right in the figure are shifted counterclockwise by θ (eg, θ = 15 °) with respect to the above embodiment. Is different in that it is provided.

  In the case of the configuration of the above-described embodiment, the mounting position of the face plate 16 has the advantage that it can be attached to the nut every 90 ° because the mounting holes 16a are arranged equally, but depending on the mounting position of the face plate 16 The position of the adjustment long hole 16t in the circumferential direction changes. In this respect, if the mounting holes 16a are unevenly distributed as in the fifth modification, the mounting position with respect to the nut is limited to two positions every 180 °, so the circumference of the adjustment long hole 16t with respect to the nut is limited. There is an advantage that the position in the direction can be always fixed.

It is a perspective view showing one embodiment of a ball screw concerning the present invention. It is a figure explaining the sealing device with which both ends of a nut are attached, the figure (a) shows the section containing the axis of a nut, and the figure (b) is the A section enlarged view in the figure (a). It is. It is explanatory drawing of the fixing member which comprises a sealing device, The figure (a) is the front view, (b) is a side view, (c) is the B section enlarged view in the figure (b). It is a figure (a)-(c) explaining the mounting method of the seal device concerning one embodiment of the present invention. It is a figure explaining the modification (1st modification) of the sealing device which concerns on this invention, The figure has shown the figure corresponding to FIG. It is a figure explaining the modification (2nd modification) of the sealing device which concerns on this invention, The figure has shown the figure corresponding to FIG. It is a figure explaining the modification (3rd modification) of the sealing device which concerns on this invention, The figure has shown the figure corresponding to FIG. It is a figure explaining the modification (4th modification) of the sealing device which concerns on this invention, The figure has shown the figure corresponding to FIG. It is a figure explaining the modification (5th modification) of the sealing device which concerns on this invention, The figure has shown the figure corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ball screw 2 Screw shaft 2a Screw groove 3 Nut 3a Screw groove 4 Ball 6 Ball rolling path 7 Return tube 8 Flat surface 9 Through-hole 10 Sealing device 12 Seal member 14 Lip part 16 Face plate (fixing member)
20 Fixing bolt 32 Seal mounting step 34 Seal seat surface 36 Face plate mounting step 38 Face plate seat surface 40 Tap hole

Claims (4)

A screw shaft having a helical thread groove on the outer peripheral surface, a nut having a helical thread groove on the inner peripheral surface opposite to the screw groove of the screw shaft, and a screw shaft and a screw groove between the nuts. A ring-shaped seal member having a lip portion that is provided on the nut end portion and slidably contacts the outer peripheral surface of the screw shaft; and a plurality of rolling elements that are movably interposed. An annular fixing member for fixing the sealing member to the nut end, and a sealing device comprising:
The fixing member is attached to the nut end portion so as to cover the seal member from the outside in the axial direction, and an outer peripheral portion of an annular surface facing the nut end portion is in direct contact with the surface on the nut side. The seal member is sandwiched between an inner peripheral portion of an annular surface facing the nut end portion and the nut end portion, and the seal member is moved in the axial direction, the circumferential direction, and the radial direction. The ball screw sealing device is characterized in that both are constrained simultaneously.   2. The ball screw sealing device according to claim 1, wherein a portion of the fixing member that sandwiches the seal member between the nut end portions is an uneven surface. 3.   The seal member has a shape in which the shape of the lip portion approximates the cross section of the screw shaft, and the thickness in the axial direction is less than one lead of the screw shaft. The ball screw sealing device according to claim 1 or 2. A screw shaft having a helical thread groove on the outer peripheral surface, a nut having a spiral thread groove facing the screw groove of the screw shaft on the inner peripheral surface, a screw groove of the screw shaft, and a screw groove of the nut A ring-shaped seal member having a plurality of rolling elements interposed between them, a lip portion provided at the end of the nut and in sliding contact with the outer peripheral surface of the screw shaft, and the seal member A ball screw provided with a sealing device having an annular fixing member to be fixed to an end,
A ball screw, wherein the ball screw sealing device according to claim 1 is mounted as the sealing device.

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