JP2014126113A - Ball screw device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball screw device for which a dustproof member can be easily attached to a nut.SOLUTION: In a ball screw device (1) which has a recessed part (6) formed at an inner peripheral end of a nut (4) that a screw shaft (2) passes through and includes a dustproof member (5) at the recessed part (6), the dustproof member (5) is formed of a cylindrical elastic member to which the screw shaft (2) is inserted and has at least one projection (8) projected in an outer diameter direction from an outer peripheral surface of the dustproof member (5), and the recessed part (6) is in such a groove shape in which the dustproof member (5) can be fitted and is provided with an engaged part (7) with which the projection (8) is engaged.

Description

  The present invention relates to a ball screw device used in, for example, a steering device, a heavy object moving device, a processing machine, a precision positioning device, and the like.

  2. Description of the Related Art Conventionally, a ball screw device including a dustproof member for preventing foreign matter such as dust, dust, and dust from entering a nut is known. As such a ball screw device, there is also known a configuration in which the dustproof member is attached to the nut by fixing the dustproof member with a set screw inserted from the outer peripheral side of the nut (for example, Patent Document 1). See).

A ball screw device used as a mechanical element that converts rotational motion into linear motion generally has a screw shaft and a cylindrical nut provided on the outer periphery of the screw shaft. A plurality of balls are incorporated between the formed spiral ball rolling groove and the spiral ball rolling groove formed on the inner peripheral surface of the nut.
In such a ball screw device, if a foreign matter such as dust adhering to the surface of the screw shaft enters the inside of the nut, the smooth rolling motion of the ball is hindered. Often attached to the end face of

  An example of a ball screw device provided with such a dustproof member is described in Patent Document 2. In this ball screw device, as shown in FIG. 25, large-diameter step portions 2053 for attaching a seal are formed at both ends of a nut 2052 screwed onto a screw shaft 2050 via a ball 2051. In addition, radial screw holes 2054 that open to the inner peripheral surface of the large-diameter stepped portion 2053 are formed in both end portions of the nut 2052. That is, one or two radial screw holes 2054 that penetrate from the outer peripheral surface 2052a of the nut 2052 and the flange peripheral surface (not shown) to the respective large diameter step portions 2053 are formed. After the seal 2055 is fitted to the large-diameter step portion 2053, the set screw 2056 is fastened to the screw hole 2054, thereby fixing the seal 2055 in the circumferential direction and the axial direction.

A ball screw device used as a mechanical element that converts rotational motion into linear motion generally has a screw shaft and a cylindrical nut provided on the outer periphery of the screw shaft. A plurality of balls are incorporated between the formed spiral ball rolling groove and the spiral ball rolling groove formed on the inner peripheral surface of the nut.
In such a ball screw device, if a foreign matter such as dust adhering to the surface of the screw shaft enters the inside of the nut, the smooth rolling motion of the ball is hindered. Often attached to the end face of

  Here, since the ball screw device described in Patent Document 2 described above is provided with the screw hole 2054 in the nut 2052, the labor required for the processing may reduce the yield. In particular, when forming the screw hole 2054, when the thickness of the nut 2052 is large, it is necessary to process not only the tapped hole processed with the female screw groove but also the drill hole. Variations occurred and there was room for improvement.

Therefore, the present inventors formed an engagement groove in the circumferential direction having a predetermined distance from the axial end on the inner circumferential surface of the nut, and formed a cylindrical shape on the outer circumferential surface. The engagement piece is elastically deformed and engaged with the engagement groove to invent a ball screw device including a dustproof member that seals a gap between the screw shaft and the nut.
In the ball screw device having such a configuration, since one or more grooves are provided in the axial direction on the outer peripheral surface of the dustproof member, when the dustproof member is extracted, the through hole of the dustproof member is The threaded shaft is penetrated, and the inner wall of the groove is pressed toward the central axis by the protrusion of the jig to release the engagement of the engagement piece with the engagement groove.

JP-A-5-302656 Japanese Patent Laid-Open No. 2003-130171, FIG.

  However, the conventional ball screw device as described above has a problem that it takes much time to attach the dust-proof member to the nut. Specifically, for example, as shown in FIG. 24, the ball screw device 1011 is assembled (FIG. 24A), and a drill hole is formed in the dust-proof member 1015 with a drill inserted from the outer peripheral side of the nut 1014 (FIG. b)), the ball screw device 1011 is disassembled (FIG. 24 (c)), and air is blown onto the disassembled screw shaft 1012, nut 1014, and dustproof member 1015 to remove the cutting chips of the drill (FIG. 24 (d)). Then, the ball screw device 1011 is assembled again, the dust-proof member 1015 is fixed with the set screw 1016 (FIG. 24 (e)), and the set screw 1016 is removed from the dust-proof member 1015 by measuring the insertion depth of the set screw 1016 with a caliper. It was necessary to perform a cumbersome work of confirming that it was inserted into the hole (FIG. 24 (f)).

  In addition, since the ball screw device described in Patent Document 2 is provided with the screw hole 2054 in the nut 2052, the labor required for the processing may reduce the yield. In particular, when forming the screw hole 2054, when the thickness of the nut 2052 is large, it is necessary to process not only the tapped hole processed with the female screw groove but also the drill hole. Variations occurred and there was room for improvement.

  Furthermore, as shown in FIG. 26, when the dust-proof member provided in the ball screw device in which the flange portion is provided on the screw shaft 2010 is extracted, the presence of this flange portion causes the groove portion of the dust-proof member on the flange portion side. The protrusion of the jig cannot be reached. As a result, the dustproof member may not be extracted using the jig, and there is room for examination.

Accordingly, the present invention has been made paying attention to the above-mentioned problems, and an object thereof is to provide a ball screw device in which a dustproof member can be easily attached to a nut.
Another object of the present invention is to provide a ball screw device capable of easily attaching and detaching a dustproof member regardless of the thickness of the nut.
Another object of the present invention is to provide a dustproof member extraction jig capable of easily extracting a dustproof member provided at an axial end of a ball screw device having a screw shaft provided with a flange portion. Is to provide.

A ball screw device according to an embodiment of the present invention for solving the above-described problem has a recess formed in an inner peripheral end of a nut through which a screw shaft passes, and includes a dustproof member in the recess.
The dust-proof member is made of a cylindrical elastic member through which the screw shaft is inserted, and has at least one protrusion protruding in the outer diameter direction from the outer peripheral surface of the dust-proof member,
The recessed portion has a groove shape into which the dust-proof member can be fitted, and a locked portion to which the protrusion is locked is provided.

That is, a ball screw device according to an embodiment includes a screw shaft, a nut provided on an outer periphery of the screw shaft, a spiral ball rolling groove formed on an outer peripheral surface of the screw shaft, and an inner periphery of the nut. A plurality of balls provided between the spiral ball rolling grooves formed on the surface,
On the inner peripheral surface (the recessed portion) of the nut, an engagement groove (the locked portion) is formed in the circumferential direction with a predetermined distance from the axial end portion,
A dust-proof member that has a cylindrical shape and is elastically deformed and engaged with the engagement groove by the engagement piece formed on the outer peripheral surface thereof to seal the gap between the screw shaft and the nut is attached to the nut. It is done.

Further, the ball screw device is provided with at least one groove portion in an axial direction on an outer peripheral surface of the dust-proof member, and the inner wall of the groove portion is pressed in the direction of the central axis by a protrusion of a jig, thereby engaging the engagement portion. The engagement of the engagement piece may be released from the groove.
In the ball screw device, the groove portions may be provided at equal intervals in the circumferential direction.
In the ball screw device, a plurality of convex portions that are in contact with the inner peripheral surface of the nut may be provided annularly and in pieces on the outer peripheral surface of the dust-proof member.
In the ball screw device, an end surface of the dust-proof member facing the nut may be protruded in the insertion direction from the protrusion.

In order to solve the above problems, a dustproof member extraction jig according to an embodiment of the present invention,
A screw shaft;
A nut provided on the outer periphery of the screw shaft, having a predetermined distance from an end in the axial direction and having an engagement groove formed on the inner peripheral surface in the circumferential direction;
A plurality of balls provided between a spiral ball rolling groove formed on the outer peripheral surface of the screw shaft and a spiral ball rolling groove formed on the inner peripheral surface of the nut;
An engagement piece that is elastically deformed and engaged with the engagement groove is formed on the outer peripheral surface and attached to the nut, and at least one groove portion along the axial direction is provided on the outer peripheral surface to form a cylindrical dust-proof structure. And having a member
It has an arcuate cross-sectional shape with a notch larger than the diameter of the screw shaft, and the engagement piece is disengaged from the engagement groove by pressing the inner wall of the groove portion toward the central axis. A first member provided at an end so that the plurality of protrusions project in the axial direction and an arc-shaped cross-sectional shape, and the first member is detachably attached to the first member in the circumferential direction to form the cylindrical shape. 2 members.

Further, the dustproof member extraction jig has one or more protrusions for releasing the engagement of the engagement piece from the engagement groove by pressing the inner wall of the groove portion toward the central axis on the second member. You may provide in an edge part so that it may protrude in an axial direction.
Moreover, the said dust-proof member extraction jig | tool may be provided with the said protrusion in the circumferential direction at equal intervals.

According to the ball screw device of an embodiment of the present invention, it is possible to provide a ball screw device in which a dustproof member can be easily attached to a nut.
In addition, according to the ball screw device of another embodiment of the present invention, it is possible to provide a ball screw device that can easily attach and detach the dust-proof member regardless of the thickness of the nut.
In addition, according to the ball screw device of an embodiment of the present invention, it is possible to easily extract the dust-proof member provided at the end portion in the axial direction of the ball screw device including the screw shaft provided with the flange portion. A dustproof member extraction jig that can be provided can be provided.

It is a fragmentary sectional view which shows the structure of the ball screw apparatus which concerns on 1st, 2nd embodiment. It is a figure which shows the structure of the dust-proof member in 1st Embodiment, (a) is a rear view, (b) is sectional drawing, (c) is a top view, (d) is a front view. It is a figure which shows a mode that a dust-proof member is attached to a nut in 1st Embodiment. It is a figure which shows the modification (dust-proof member provided with one seal part and two latching | locking parts) of the dust-proof member in 1st Embodiment, (a) is a rear view, (b) is sectional drawing, (c). Is a top view, and (d) is a front view. It is a figure which shows the modification (dustproof member provided with one seal part and three latching | locking parts) in the dustproof member in 1st Embodiment, (a) is a rear view, (b) is X- of (a). X sectional drawing, (c) is a top view, (d) is a front view. It is a figure which shows the modification (dust-proof member provided with one seal part and four latching | locking parts) in the dust-proof member in 1st Embodiment, (a) is a rear view, (b) is sectional drawing, (c) Is a top view, and (d) is a front view. It is a figure which shows the modification (dustproof member provided with one seal part and six latching | locking parts) in the dustproof member in 1st Embodiment, (a) is a rear view, (b) is sectional drawing, (c). Is a top view, and (d) is a front view. It is a figure which shows the structure of the dust-proof member in 1st, 2nd embodiment, (a) is sectional drawing of the dust-proof member in 1st Embodiment, (b) is the elements on larger scale of (a), (c) is 1st. Sectional drawing of the dustproof member in 2 embodiment, (d) is the elements on larger scale of (c). It is a figure which shows a mode that a dust-proof member is attached to a nut in 2nd Embodiment. It is sectional drawing which follows the axial direction which shows the structure in 3rd Embodiment of a ball screw apparatus. It is a figure which shows the structure of the dust-proof member in 3rd Embodiment of a ball screw apparatus, (a) is a front view, (b) is a top view, (c) is a left view, (d) is a rear view. . It is a figure which shows the attachment procedure of the dustproof member in 3rd Embodiment of a ball screw apparatus, (a) is sectional drawing in alignment with the axial direction before attaching a dustproof member to a nut, (b) is a dustproof member as a nut. It is sectional drawing which follows the axial direction after mounting | wearing. It is a figure which shows the jig | tool used in the case of removal of the dust-proof member in 3rd Embodiment of a ball screw apparatus, (a) is a perspective view, (b), (c) is the elements on larger scale of (a). is there. It is a figure which shows the removal procedure of the dustproof member in 3rd Embodiment of a ball screw apparatus, (a) is sectional drawing in alignment with the axial direction in the state with which the dustproof member was mounted | worn to the nut, (b) is a jig | tool insertion Sectional drawing along the previous axial direction, (c) is a sectional view along the axial direction when the jig is inserted, and (d) is a sectional view along the axial direction when the dustproof member is removed from the nut. It is a figure which shows the structure in embodiment with a dust-proof member extraction jig | tool, (a) is a perspective view, (b) is a perspective view when decomposed | disassembled into a 1st member and a 2nd member, (c), (d (A) is a partially enlarged view of (a), and (e) is a perspective view showing a configuration of a dustproof member extraction jig of another example. It is sectional drawing which follows the axial direction which shows the structure of the ball screw apparatus provided with the screw shaft which has a flange part. It is a figure which shows the structure of a dustproof member, (a) is a front view, (b) is a top view, (c) is a left view, (d) is a rear view. It is a figure which shows the procedure which attaches a dustproof member to a ball screw apparatus, (a) is sectional drawing in alignment with the axial direction before attaching a dustproof member to a nut, (b) is an axial direction after attaching a dustproof member to a nut FIG. It is a figure which shows the removal procedure of the dustproof member installed in the opposite side to the flange part of the screw shaft in embodiment with a dustproof member extraction jig | tool, (a) is the axial direction of the state in which the dustproof member was attached to the nut (B) is a cross-sectional view along the axial direction before inserting the jig, (c) is a cross-sectional view along the axial direction when the jig is inserted, and (d) is a drawing of the dustproof member from the nut. It is sectional drawing which follows an axial direction at the time. It is a figure which shows the removal procedure of the dustproof member installed in the flange part side of the screw shaft in embodiment with a dustproof member extraction jig | tool, (a) arrange | positions a 1st member with respect to the dustproof member with which the nut was mounted | worn. A sectional view along the axial direction in the state where it is made, (b) is a sectional view along the axial direction in which a dustproof member extraction jig comprising the first member and the second member is arranged on the screw shaft, (c) is a dustproof member extraction Sectional drawing which follows an axial direction when a jig | tool is inserted in a nut, (d) is sectional drawing which follows an axial direction when a dustproof member is extracted from a nut. It is a figure which shows the structure of the dustproof member and dustproof member extraction jig | tool in 5th Embodiment of a ball screw apparatus, (a) is a front view of a dustproof member, (b) is a top view of a dustproof member, (c) is The left view of a dustproof member, (d) is a rear view of a dustproof member, (e) is a perspective view of a dustproof member extraction jig, (f) is an important section enlarged view of (e). It is a figure which shows the structure of the dustproof member in 6th Embodiment of a ball screw apparatus, (a) is a rear view of a dustproof member, (b) is a top view of a dustproof member, (c) is a left view of a dustproof member. (D) is sectional drawing in alignment with the axial direction at the time of incorporating a dust-proof member in a ball screw apparatus, (e) is a principal part enlarged view of (d). It is a figure which shows the structure of the dustproof member in 7th Embodiment of a ball screw apparatus, (a) is a left view of a dustproof member, (b) is a rear view of a dustproof member, (c) is a ballscrew. Sectional drawing in alignment with the axial direction at the time of incorporating in an apparatus, (d) is sectional drawing in alignment with the axial direction at the time of incorporating a dustproof member in a ball screw apparatus conventionally. It is a figure which shows an example of a mode that a dust-proof member is attached to a nut in the conventional ball screw apparatus. It is sectional drawing which follows the axial direction which shows the structure of the conventional ball screw apparatus. It is sectional drawing which follows the axial direction which shows the structure of the ball screw apparatus provided with the conventional screw shaft which has a flange part.

Embodiments of a ball screw device according to the present invention will be described below with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the ball screw device 1 according to the first embodiment includes a screw shaft 2 and nuts 4 screwed onto the screw shaft 2 via a plurality of balls 3. The screw shaft 2 is made of an elongated cylindrical metal member. On the outer peripheral surface of the screw shaft 2, a thread groove 2a having a substantially arc-shaped cross section is formed in a spiral shape.

The nut 4 is made of a substantially cylindrical metal member in which a circular through hole larger than the outer diameter of the screw shaft 2 is formed. A thread groove 4 a having a substantially arc-shaped cross section is formed in a spiral shape on the inner peripheral surface of the nut 4 so as to correspond to the thread groove 2 a of the screw shaft 2.
The screw shaft 2 is inserted through the through-hole of the nut 4, and the screw grooves 2a and 4a face each other to form a ball rolling path. A plurality of balls 3 made of metal are loaded in the rolling path, whereby the screw shaft 2 and the nut 4 are screwed together.

  With such a configuration, by rotating any one of the screw shaft 2 and the nut 4, the plurality of balls 3 can roll in the rolling path and the other can be linearly moved in the axial direction. The nut 4 is provided with a circulation part (not shown) that forms a circulation path for circulating the ball 3 that has rolled to reach the end point of the rolling path to the starting point of the rolling path. Therefore, the plurality of balls 3 can circulate in the rolling path through the circulation path.

In the present embodiment, the screw shaft 2 has two thread grooves 2a with a phase shifted by 180 degrees. Therefore, two sets of the thread groove 4a of the nut 4, the plurality of balls 3, and the circulation parts (not shown) are also provided so as to correspond to this.
In the ball screw device 1 according to the present embodiment, as shown in FIG. 1, in order to prevent foreign matter such as dust, dust, and dust from entering the nut 4 at both end portions on the axial direction side of the nut 4, A dustproof member 5 that closes the gap between the both ends and the screw shaft 2 is provided.

  The dustproof member 5 is made of a substantially cylindrical resin member in which a circular through-hole is formed. The through hole of the dustproof member 5 is designed to have a diameter slightly larger than the outer diameter of the screw shaft 2 so that the dustproof member 5 does not contact the screw shaft 2 when the dustproof member 5 is attached to the nut 4. ing. Moreover, the diameter of the outer peripheral surface of the dust-proof member 5 is designed so that the dust-proof member 5 can be fitted into a later-described recess 6 of the nut 4.

As shown in FIG. 2, the dust-proof member 5 is formed with a rectangular columnar cutout portion 13 so as to open the outer peripheral surface side and the front surface side, and the notch portion 13 is made of resin. Part 7 is provided.
The locking portion 7 is for preventing the dustproof member 5 attached to the nut 4 from being detached from the nut 4, and is formed integrally with the dustproof member 5. Such a locking portion 7 includes a claw 8 that protrudes in the outer diameter direction at a front side position on the outer peripheral surface of the dust-proof member 5, and an arm portion 9 that supports the claw 8.

  As shown in FIG. 2 (b), the claw 8 is inclined toward the central axis O side from the back side (left side in FIG. 2 (b)) of the dustproof member 5 toward the front side (right side in FIG. 2 (b)). The inclined surface 8a is formed. The distance between the front end of the inclined surface 8a and the central axis O is smaller than the radius of the inner peripheral surface of the recess 6. Thereby, when attaching the dust-proof member 5 to the nut 4, it becomes possible to insert the nail | claw 8 into the recessed part 6 smoothly.

The arm portion 9 is provided so as to extend in the axial direction from the bottom surface of the notch portion 13 as shown in FIG. 2B, and the claw 8 having the above-described configuration is provided at the tip thereof. Specifically, the arm portion 9 in the present embodiment is provided with a U-shaped deep groove so as to surround the claw 8 formed on the outer peripheral surface of the dust-proof member 5 as seen from the front side as shown in FIG. It is formed by that. Since a predetermined gap is secured around the arm portion 9 in this way, the arm portion 9 and the claw 8 are easily elastically deformed in the radial direction. Therefore, when attaching the dustproof member 5 to the nut 4, the claw 8 can be more smoothly inserted into the recessed portion 6.
In the present embodiment, the locking portions 7 having the above-described configuration are provided at two symmetrical positions with respect to the center axis O of the dust-proof member 5 as shown in FIG.

As shown in FIG. 2 (b), a resin-made seal portion 11 is integrally formed at the back side end portion on the inner peripheral surface of the dust-proof member 5 in a thin plate shape extending in the inner diameter direction. The seal portion 11 is for closing the gap between the dustproof member 5 and the screw groove 2a of the screw shaft 2. In this embodiment, the seal portion 11 has a crescent shape as viewed from the front side as shown in FIG. Yes. Specifically, the seal portion 11 is designed to have a size such that the seal portion 11 does not contact the screw groove 2 a of the screw shaft 2 when the dustproof member 5 is attached to the nut 4.
As described above, in the present embodiment, since the two screw grooves 2a are formed in the screw shaft 2, the seal portion 11 also corresponds to the center of the dust-proof member 5 as shown in FIG. It is provided at two locations that are symmetrical with respect to the axis O.

As shown in FIG. 1, recessed portions 6 for attaching the dustproof member 5 are formed at both end portions on the axial direction side of the nut 4.
The recessed portion 6 has a groove shape that is concentric with the through-hole of the nut 4 and is recessed from the surface of both end portions of the nut 4 so as to be larger in diameter than the through-hole in order to store and hold the dust-proof member 5. An inner groove portion 12 is provided at the bottom portion of the recess portion 6 as a portion to be locked to receive the claw 8 of the locking portion 7 in the dust-proof member 5 and to which the claw 8 is locked. The inner groove portion 12 is a groove that extends in the outer diameter direction at the bottom portion of the recess portion 6 and is formed over the entire circumference of the recess portion 6.

Under such a configuration, the dust-proof member 5 in this embodiment can be attached to the nut 4 by a simple attachment method as shown in FIG.
First, an operator prepares a nut 4 into which a screw shaft 2 is inserted via a plurality of balls 3. Then, the operator inserts the screw shaft 2 into the through hole of the dustproof member 5 with the front surface of the dustproof member 5 facing the nut 4 as shown in FIG.
Next, the operator pushes the dust-proof member 5 into the recess 6 of the nut 4 as shown in FIG. At this time, the engaging portion 7 of the dust-proof member 5 is elastically deformed in the inner diameter direction by the inclined surface 8 a of the claw 8 abutting against the corner portion of the recessed portion 6 and enters the recessed portion 6.

  Then, the operator further pushes the dust-proof member 5 into the recessed portion 6 as shown in FIG. Thereby, the outer peripheral surface of the dust-proof member 5 is fitted to the inner peripheral surface of the recessed portion 6, and the claw 8 of the locking portion 7 enters the inner groove portion 12. At this time, the locking portion 7 is elastically deformed in the outer diameter direction to return to the original shape, and the claw 8 is locked to the inner groove portion 12. Thereby, it can prevent that the dustproof member 5 comes off from the dent part 6. FIG. Finally, the operator adjusts the rotational direction position of the dust-proof member 5 so that the seal portion 11 of the dust-proof member 5 enters the screw groove 2a of the screw shaft 2 appropriately.

  Thus, the attachment of the dust-proof member 5 to the nut 4 is completed, and the gap between both ends of the nut 4 and the screw shaft 2 is closed with the dust-proof member 5, thereby preventing foreign matter from entering the nut 4. Note that the dust-proof member 5 in the present embodiment can also prevent the lubricant supplied into the nut 4 from being exposed to the outside of the nut 4.

  As described above, in the ball screw device 1 according to this embodiment, an operator can easily attach the dust-proof member 5 to the nut 4. In particular, it is not necessary to perform any of the complicated operations shown in FIGS. 24 (b) to 24 (f) as compared with the conventional ball screw device described above. In addition, the number of parts can be reduced because the set screw is unnecessary. Therefore, the manufacturing cost can be reduced.

  The ball screw device 1 according to the present embodiment is a so-called double ball screw device in which two screw grooves 2a are formed on the screw shaft 2 as described above. However, the present invention is not limited to this, and the configuration of the dustproof member 5 and the recessed portion 6 of the nut 4 in the present embodiment can be applied to a multi-row ball screw device other than two or a single-row ball screw device. When the configuration is applied to, for example, a single ball screw device, the seal portion 11 of the dustproof member 5 may be provided only at one place as shown in FIG.

  In the ball screw device 1 according to the present embodiment, the dust-proof member 5 includes two locking portions 7 as described above. However, the number of the locking portions 7 is not limited to this, and may be one or three or more. For example, as shown in FIG. 5, the structure having three locking portions 7 so as to divide the outer periphery of the dust-proof member 5 into three equal parts, and as shown in FIG. It is good also as a structure which has the latching | locking part 7, or has the six latching | locking parts 7 so that the outer periphery of the dust-proof member 5 may be divided into 6 equally as shown in FIG. As shown in FIGS. 5 to 7, the number of the locking portions 7 of the dust-proof member 5 is three or more, so that the dust-proof member 5 can be better prevented from coming off from the recessed portion 6. 5 to 7 all show a dustproof member for a single ball screw device.

(Second Embodiment)
About the ball screw apparatus 1 which concerns on 2nd Embodiment shown in FIG. 1, description is abbreviate | omitted about the structure similar to the said 1st Embodiment, and a different structure is demonstrated in detail.
As shown in FIGS. 8C and 8D, the dust-proof member 5 in the present embodiment has a shape in which the locking portion 7 is curved toward the outer diameter direction. Specifically, in the dust-proof member 5 in the first embodiment, as shown in FIGS. 8A and 8B, the arm portion 9 is parallel to the axial direction and the arm portion viewed from the axial direction. The distance A between the outermost surface 9 and the central axis O is the same as the radius B of the outer peripheral surface of the dust-proof member 5. On the other hand, in the dustproof member 5 in the present embodiment, the distance C between the outermost surface of the arm portion 9 and the central axis O viewed from the axial direction is larger than the radius B of the outer peripheral surface of the dustproof member 5.

The dustproof member 5 having such a configuration can be easily attached to the nut 4 by a method similar to the attachment method described in the first embodiment (see FIG. 9).
In particular, in this embodiment, as shown in FIG. 9C, when the dust-proof member 5 is fitted in the recessed portion 6 and the claw 18 of the locking portion 7 enters the inner groove portion 12, the locking portion 7 is outside. The claw 8 is locked to the inner groove portion 12 by elastic deformation in the radial direction. However, as described above, the locking portion 7 curved in the outer diameter direction does not return to the original shape, and the arm portion 9 remains stretched in the outer diameter direction, that is, the outer peripheral surface of the arm portion 9 is recessed. The state of being pressed against the inner peripheral surface is maintained. With this configuration, even if a rotational force is applied to the dust-proof member 5 attached to the nut 4, a large frictional force is generated between the outer peripheral surface of the arm portion 9 and the inner peripheral surface of the recessed portion 6. Therefore, it is possible to prevent the dustproof member 5 from rotating in the recessed portion 6.

  As described above, the ball screw device 1 according to the present embodiment can achieve the same effects as those of the first embodiment. Here, when the dust-proof member 5 attached to the nut 4 rotates, the position of the seal portion 11 of the dust-proof member 5 that has appropriately entered the screw groove 2a of the screw shaft 2 is shifted. For this reason, the malfunction that the seal part 11 contacts the screw shaft 2 and the rotational torque of the screw shaft 2 becomes extremely large occurs. On the other hand, since the ball screw device 1 according to the present embodiment can prevent the dust-proof member 5 from rotating as described above, the occurrence of the above-described problem can be prevented.

In addition, the structure of the dustproof member 5 and the recessed part 6 of the nut 4 in this embodiment is applicable also to the multi-row ball screw apparatus other than a 2-row, or a 1-row ball screw apparatus similarly to the said 1st Embodiment. Is possible.
Moreover, the number of the latching | locking parts 7 of the dustproof member 5 in this embodiment is not restricted to two like the said 1st Embodiment. By making the number of the locking portions 7 of the dustproof member 5 three or more, it is possible to better prevent the dustproof member 5 from coming off the recessed portion 6. In addition to this, since the frictional force generated between the arm portion 9 of the locking portion 7 and the recessed portion 6 becomes larger, the rotation of the dustproof member 5 can be prevented more favorably.

  Moreover, the latching | locking part 7 of the dustproof member 5 in this embodiment is carrying out the shape curved toward the outer-diameter direction as mentioned above. However, the shape of the locking portion 7 is not limited to this, and may be any shape as long as the distance between the outermost surface of the arm portion 9 and the central axis O viewed from the axial direction is larger than the radius of the outer peripheral surface of the dust-proof member 5. For example, the rotation of the dust-proof member can be prevented in the same manner as in the present embodiment by making the arm part 9 thick in the outer diameter direction.

Further, in the ball screw device 1 according to the present embodiment, when the dust-proof member 5 is attached to the nut 4 as described above, the seal portion 11 of the dust-proof member 5 does not contact the screw groove 2a of the screw shaft 2 so-called non-contact. It is a ball screw device provided with a dustproof member of the type. However, the present invention is not limited to this, and the configuration of the dust-proof member 5 and the recessed portion 6 of the nut 4 in the present embodiment is also applied to a ball screw device including a so-called contact-type dust-proof member in which the seal portion 11 contacts the screw groove 2a. It is possible.
As mentioned above, according to each said embodiment, the ball screw apparatus which can attach a dust-proof member easily with respect to a nut is realizable.

(Third embodiment)
Hereinafter, a third embodiment of the ball screw device will be described with reference to the drawings.
FIG. 10 is a cross-sectional view along the axial direction showing the configuration of the ball screw device according to the third embodiment. FIG. 11 is a diagram showing the configuration of the dust-proof member in the third embodiment of the ball screw device, where (a) is a front view, (b) is a plan view, (c) is a left side view, and (d). ) Is a rear view.
As shown in FIG. 10, the ball screw device 101 of this embodiment includes a screw shaft 110, a nut 120, and a plurality of balls 130.
The screw shaft 110 has a spiral ball rolling groove 111 on the outer peripheral surface, and a spiral ball rolling groove 121 is formed on the inner peripheral surface of the nut 120 provided on the outer periphery of the screw shaft 110. It is formed with the same lead as the moving groove 111.

  The ball rolling grooves 111 and 121 are opposed to each other, and a plurality of balls 130 provided between the ball rolling grooves 111 and 121 are rolled when the screw shaft 110 rotates relative to the nut 120. It rolls between the grooves 111 and 121. Then, the ball 130 rolled between the ball rolling grooves 111 and 121 passes through a ball return tube (not shown) assembled to the nut 120, for example, and is returned to the original position. Between these ball rolling grooves 111 and 121 and the ball return tube form a rolling path.

[Engagement groove]
Further, a circular engagement groove 122 is provided in the circumferential direction at a predetermined distance from an end portion in the axial direction on the inner peripheral surface of the nut 120. Here, the inner peripheral surface of the nut 120 corresponds to the recessed portion 6 in the first embodiment described above. Further, the engagement groove 122 of the present embodiment corresponds to the recessed portion 6 in the first embodiment described above, particularly the inner groove portion 12. One engagement groove 122 is preferably provided from each end of the nut 120, and a plurality of engagement grooves 122 are provided as necessary. Here, the predetermined distance is set based on an axial dimension of a dustproof member 140 described later.

<Dustproof material>
As shown in FIGS. 11A to 11D, the dustproof member 140 has a cylindrical shape. On the outer peripheral surface 140a of the dustproof member 140, a plurality of engagement pieces 141 (four in this embodiment) are provided at equal intervals. These engagement pieces 141 have elasticity and can be engaged with the engagement grooves 122. Note that the engagement piece 141 is preferably formed integrally with an elastic material together with the dustproof member 140. In addition, the radial thickness on the end surface side of the dust-proof member 140 where the engagement piece 141 is not provided is larger than the radial thickness of the engagement piece 141. This is because when the engagement piece 141 is elastically deformed, the bending moment on the end surface side of the dust-proof member 140 where the engagement piece 141 is not provided is larger than the bending moment in the engagement piece 141. This is because the second moment of section is increased.
Further, the dust-proof member 140 has a groove 142 in which an outer peripheral surface 140a is cut out along the axial direction on the end surface opposite to the end surface on which the engagement piece 141 is provided, corresponding to each engagement piece 141. Are provided (four in this embodiment).

<Attaching the dustproof member>
Next, a procedure for attaching the dustproof member 140 will be described with reference to FIG.
12A and 12B are diagrams showing a procedure for attaching the dust-proof member in the present embodiment. FIG. 12A is a cross-sectional view taken along the axial direction before the dust-proof member is attached to the nut, and FIG. 12B is a diagram showing the dust-proof member attached to the nut. It is sectional drawing which follows a later axial direction.
As shown in FIGS. 12A and 12B, the dust-proof member 140 is fitted into the nut 120 while the outer peripheral surface 140 a and the inner peripheral surface 120 a of the nut 120 are brought into contact with each other. At this time, the plurality of engagement pieces 141 are engaged with the engagement grooves 122 while being elastically deformed, whereby the dustproof member 140 is fixed to the nut 120. Thus, the dust-proof member 140 attached to the nut 120 seals the gap between the screw shaft 110 and the nut 120.

<Removal of dustproof member>
Next, a procedure for removing the dustproof member will be described with reference to FIGS.
FIG. 13 is a view showing a jig used in removing the dust-proof member in the present embodiment, wherein (a) is a perspective view, and (b) and (c) are partial enlarged views of (a). FIG. 14 is a diagram showing a procedure for removing the dust-proof member in the present embodiment, where (a) is a cross-sectional view along the axial direction of the dust-proof member mounted on the nut, and (b) is a jig insertion. Sectional drawing along the previous axial direction, (c) is a sectional view along the axial direction when the jig is inserted, and (d) is a sectional view along the axial direction when the dustproof member is removed from the nut.

  As shown in FIGS. 13A to 13C, a cylindrical jig 145 is used when removing the dustproof member 140 in the present embodiment. In the jig 145, the diameter of the outer peripheral surface 145a is made equal to the outer diameter of the dust-proof member 140 (the diameter of the outer peripheral surface 140a). In addition, a plurality of protrusions 146 are provided on one end surface of the jig 145 so as to protrude in the axial direction corresponding to the position where the groove 142 of the dust-proof member 140 is formed. As shown in FIGS. 13B and 13C, the tip portions of these protrusions 146 are curved from the inner surface (the surface on the central axis side of the jig 145) to the outer surface.

  When removing the dust-proof member 140 from the nut 120 using such a jig 145, first, the positions of the plurality of grooves 142 with respect to the dust-proof member 140 (see FIG. 14A) attached to the nut 120. Are aligned with the positions of the plurality of protrusions 146 (see FIG. 14B).

  Next, a plurality of protrusions 146 are inserted between the plurality of grooves 142 and the inner peripheral surface 120 a of the nut 120. At this time, as each projection 146 presses the inner wall 142a of each groove 142 in the direction of the central axis of the jig 145, each engagement piece 141 also has a central axis O (see FIG. a) and (d) (see FIG. 14 (c)). Here, as described above, since the curved surface is formed at the tip of each protrusion 146, when the protrusion 146 presses the inner wall 142a of the groove 142 in the direction of the central axis, the engagement groove 122 engages. The engagement of the combined piece 141 is easily released.

  Here, the dustproof member 140 is installed on the nut 120 so as to engage with the ball rolling groove 111 in order to seal between the screw shaft 110 and the nut 120. Therefore, when the dust-proof member 140 is rotated counterclockwise by the jig 145, for example, the dust-proof member 140 rotates along the ball rolling groove 111 and is removed from the nut 120 (see FIG. 14D).

As described above, the ball screw device 101 according to the present embodiment can attach and remove the dustproof member 140 to and from the nut 120 by elastic deformation, so that the dustproof member can be easily attached and detached regardless of the thickness of the nut 120. Can be.
In the present embodiment, the number of locking pieces provided on the dustproof member is four, but may be five.

(Fourth embodiment)
Here, as a fourth embodiment of the present invention, an embodiment having a dustproof member extraction jig will be described with reference to the drawings. The dustproof member extraction jig of this embodiment is a dedicated tool used to extract the dustproof member installed in the ball screw device described above and below, for example, and is used in the same manner as the jig 145 of the third embodiment. It is what

<Dustproof material extraction jig>
FIG. 15 is a view showing a dustproof member extraction jig in the present embodiment, (a) is a perspective view, (b) is a perspective view when disassembled into a first member and a second member, (c), (D) is the elements on larger scale of (a), (e) is a perspective view which shows the structure of the dustproof member extraction jig | tool of another example. FIG. 16 is a cross-sectional view along the axial direction showing the configuration of a ball screw device including a screw shaft having a flange portion. Moreover, FIG. 17 is a figure which shows the structure of a dustproof member, (a) is a front view, (b) is a top view, (c) is a right view, (d) is a rear view. FIG. 18 is a diagram showing a procedure for attaching the dustproof member to the ball screw device, wherein (a) is a cross-sectional view along the axial direction before the dustproof member is attached to the nut, and (b) is a dustproof member used as the nut. It is sectional drawing which follows the axial direction after mounting | wearing. Moreover, FIG. 19 is a figure which shows the removal procedure of the dust-proof member of the side in which the flange part of the screw shaft in this embodiment is not formed, (a) is an axial direction of the state in which the dust-proof member was attached to the nut. (B) is a sectional view along the axial direction before the jig is inserted, (c) is a sectional view along the axial direction when the jig is inserted, and (d) is a dust-proof member extracted from the nut. It is sectional drawing in alignment with an axial direction. FIG. 20 is a view showing a procedure for removing the dust-proof member on the side where the flange portion of the screw shaft in this embodiment is formed. FIG. 20A shows the first member with respect to the dust-proof member attached to the nut. Sectional view along the axial direction of the arranged state, (b) is a sectional view along the axial direction of the state where the dustproof member extraction jig comprising the first member and the second member is arranged on the screw shaft, and (c) is the dustproof member. Sectional drawing in alignment with the axial direction when the extraction jig | tool is inserted in a nut, (d) is sectional drawing in alignment with the axial direction when a dustproof member is extracted from a nut.

As shown in FIGS. 15A to 15C, the dustproof member extraction jig 200 of the present embodiment has a cylindrical shape. And the diameter of the outer peripheral surface 200a of this dustproof member extraction jig | tool 200 is made equal to the outer diameter (diameter of the outer peripheral surface 140a) of the dustproof member 140 mentioned later.
As shown in FIG. 15B, the dustproof member extraction jig 200 includes a first member 210 and a second member 220 that are detachable from each other. The first member 210 has an arcuate cross-sectional shape having a notch. The circumferential dimension of the notch is set larger than the diameter of the screw shaft 110. In addition, concave and convex portions 211 and 212 are formed at opposite circumferential end portions constituting the notch portion of the first member 210, respectively.

  The second member 220 also has an arcuate cross-sectional shape. The second member 220 has concave and convex portions 221 and 222 formed at both ends in the circumferential direction, and can be connected to the first member 210 by fitting with the concave and convex portions 211 and 212 of the first member 210. Thus, the cylindrical dustproof member extraction jig 200 is formed by connecting the first member 210 and the second member 220.

  In addition, a plurality of protrusions 230 protruding in the axial direction are provided on the axial end surfaces of the first member 210 and the second member 220. A plurality of these protrusions 230 are provided at least on the end face of the first member 210, and may be provided on the end face of the second member 220, or may not be provided. The plurality of protrusions 230 are provided at equal intervals in the circumferential direction on the end surface of the cylindrical dustproof member extraction jig 200 formed by connecting the first member 210 and the second member 220. It is preferable to be provided on at least one of the first member 210 and the second member 220.

Further, as shown in FIGS. 15 (c) and 15 (d), the tips of these protrusions 230 form a curved surface from the inner surface (the surface on the central axis side of the dustproof member extraction jig 200) to the outer surface. Has been.
Furthermore, as shown in FIG. 15 (e), as another example of the dust-proof member extraction jig, four protrusions 230 may be provided at equal intervals in the circumferential direction. At this time, the groove portions 142 of the dustproof member 140 are arranged in four equal parts corresponding to the protrusions 230. In addition, the engagement pieces 141 are also arranged in a four-way arrangement corresponding to the groove parts 142 in the four-way distribution.

<Configuration of ball screw device>
FIG. 16 is a cross-sectional view along the axial direction showing the configuration of the ball screw device provided with the dustproof member extracted by the dustproof member extraction jig of the present embodiment. Moreover, FIG. 17 is a figure which shows the structure of the dustproof member extracted from a ball screw apparatus by the dustproof member extraction jig | tool of this embodiment, (a) is a front view, (b) is a top view, (c) is Left side view, (d) is a rear view.
As shown in FIG. 16, the ball screw device 101 includes a screw shaft 110, a nut 120, and a plurality of balls 130.
The screw shaft 110 has a spiral ball rolling groove 111 on the outer peripheral surface, and a spiral ball rolling groove 121 is formed on the inner peripheral surface of the nut 120 provided on the outer periphery of the screw shaft 110. It is formed with the same lead as the moving groove 111.

The ball rolling grooves 111 and 121 are opposed to each other, and a plurality of balls 130 provided between the ball rolling grooves 111 and 121 are rolled when the screw shaft 110 rotates relative to the nut 120. It rolls between the grooves 111 and 121. Then, the ball 130 rolled between the ball rolling grooves 111 and 121 passes through a ball return tube (not shown) assembled to the nut 120, for example, and is returned to the original position. Between these ball rolling grooves 111 and 121 and the ball return tube form a rolling path.
Here, the screw shaft 110 is provided with a flange portion 112.

[Engagement groove]
Further, a circular engagement groove 122 is provided in the circumferential direction at a predetermined distance from an end portion in the axial direction on the inner peripheral surface of the nut 120. One engagement groove 122 is preferably provided from each end of the nut 120, and a plurality of engagement grooves 122 are provided as necessary. Here, the predetermined distance is set based on an axial dimension of a dustproof member 140 described later.

<Dustproof material>
As shown in FIGS. 17A to 17D, the dustproof member 140 has a cylindrical shape. A plurality of engagement pieces 141 (five in this embodiment) are provided at equal intervals on the outer peripheral surface 140a of the dustproof member 140. These engagement pieces 141 have elasticity and can be engaged with the engagement grooves 122. Note that the engagement piece 141 is preferably formed integrally with an elastic material together with the dustproof member 140. In addition, the radial thickness on the end surface side of the dust-proof member 140 where the engagement piece 141 is not provided is larger than the radial thickness of the engagement piece 141. This is because when the engagement piece 141 is elastically deformed, the bending moment on the end surface side of the dust-proof member 140 where the engagement piece 141 is not provided is larger than the bending moment in the engagement piece 141. This is because the second moment of section is increased.

  Further, the dust-proof member 140 has a groove 142 in which an outer peripheral surface 140a is cut out along the axial direction on the end surface opposite to the end surface on which the engagement piece 141 is provided, corresponding to each engagement piece 141. Are provided (five in this embodiment). Accordingly, the same number of protrusions 230 as the number of the engaging pieces 141 and the grooves 142 are provided on the dustproof member extraction jig 200.

<Attaching the dustproof member>
Next, a procedure for attaching the dustproof member will be described with reference to FIG.
18A and 18B are diagrams illustrating a procedure for attaching the dust-proof member in the present embodiment. FIG. 18A is a cross-sectional view taken along the axial direction before the dust-proof member is attached to the nut, and FIG. 18B is a diagram showing the dust-proof member attached to the nut. It is sectional drawing which follows a later axial direction.
As shown in FIGS. 18A and 18B, the dust-proof member 140 is fitted into the nut 120 while the outer peripheral surface 140a and the inner peripheral surface 120a of the nut 120 are in contact with each other. At this time, the plurality of engagement pieces 141 are engaged with the engagement grooves 122 while being elastically deformed, whereby the dustproof member 140 is fixed to the nut 120. Note that the dust-proof member 140 installed on the opposite side of the nut 120 on the side facing the flange 112 is fitted to the screw shaft 110 before the nut 120 is attached to the screw shaft 110. That is, the dustproof member 140 is fitted on the screw shaft 110 so as to be positioned between the flange portion 112 and the end portion of the nut 120 facing the flange portion 112. In this state, the nut 120 is attached to the screw shaft 110, and then the dustproof member 140 is assembled to the nut 120. Thus, the dust-proof member 140 attached to the nut 120 seals the gap between the screw shaft 110 and the nut 120.

<Removal of dustproof member>
Next, a procedure for extracting the dustproof member will be described with reference to FIGS. 15, 19, and 20.
[Removal of dustproof material installed on the side that does not interfere with the flange]
When extracting the dust-proof member 140 from the nut 120 using the dust-proof member extraction jig 200, first, the positions of the plurality of groove portions 142 with respect to the dust-proof member 140 (see FIG. 19A) attached to the nut 120. Are aligned with the positions of the plurality of protrusions 230 (see FIG. 19B).

  Next, a plurality of protrusions 230 are inserted between the plurality of grooves 142 and the inner peripheral surface 120 a of the nut 120. At this time, as each projection 230 presses the inner wall 142a of each groove 142 in the direction of the central axis of the dustproof member extraction jig 200, each engagement piece 141 also has a central axis O ( 17 (a) and 17 (d)), and is disengaged from the engagement groove 122 to release the engagement state (see FIG. 19 (c)). Here, as described above, since the curved surface 230a is formed at the tip of each protrusion 230, when the protrusion 230 presses the inner wall 142a of the groove part 142 in the direction of the central axis, The engagement of the engagement piece 141 is easily released.

  Here, the dustproof member 140 is installed on the nut 120 so as to engage with the ball rolling groove 111 in order to seal between the screw shaft 110 and the nut 120. Therefore, when the dustproof member 140 is rotated counterclockwise by the dustproof member extraction jig 200, for example, the dustproof member 140 rotates along the ball rolling groove 111 and is removed from the nut 120 (see FIG. 19D). ).

[Removal of dustproof material installed on the side that interferes with the flange]
When extracting the dust-proof member 140 from the nut 120 using the dust-proof member extraction jig 200, first, as shown in FIG. 15B, the dust-proof member extraction jig 200 is connected to the first member 210, the second member 220, and the like. Divide into 20A, the first member 210 is disposed so that the inner peripheral surface of the first member 210 surrounds the outer peripheral surface 110a on the side where the flange portion 112 of the screw shaft 110 is provided.

  Thereafter, the second member 220 is fitted to the first member 210, the dustproof member extraction jig 200 is surrounded on the outer periphery of the screw shaft 110, and the screw shaft 110 penetrates the through hole of the dustproof member extraction jig 200. To. Then, the positions of the plurality of protrusions 230 of the dustproof member extraction jig 200 and the positions of the plurality of groove portions 142 of the dustproof member 140 attached to the nut 120 are matched (see FIG. 20B).

  Next, a plurality of protrusions 230 are inserted between the plurality of grooves 142 and the inner peripheral surface 120 a of the nut 120. At this time, as each projection 230 presses the inner wall 142a of each groove 142 in the direction of the central axis of the dustproof member extraction jig 200, each engagement piece 141 also has a central axis O ( 17 (a) and 17 (d)), and is disengaged from the engagement groove 122 to release the engagement state (see FIG. 20 (c)). Here, as described above, since the curved surface is formed at the tip of each protrusion 230, when the protrusion 230 presses the inner wall 142a of the groove 142 in the direction of the central axis, the engagement groove 122 engages. The engagement of the combined piece 141 is easily released.

  Here, the dustproof member 140 is installed on the nut 120 so as to engage with the ball rolling groove 111 in order to seal between the screw shaft 110 and the nut 120. Therefore, when the dustproof member 140 is rotated counterclockwise by the dustproof member extraction jig 200, for example, the dustproof member 140 rotates along the ball rolling groove 111 and is removed from the nut 120 (see FIG. 20D). ).

  As described above, since the dustproof member extraction jig of the present embodiment is configured by the first member and the second member that are detachable from each other, the ball having the screw shaft provided with the flange portion. The dust-proof member provided at the end portion in the axial direction of the screw device can be easily removed.

  In addition, the dustproof member extraction jig | tool of this embodiment is not limited to the said embodiment, A various deformation | transformation is possible unless it deviates from the meaning of this invention. For example, in the above-described embodiment, the number of protrusions of the dustproof member extraction jig is five, but may be four, or any number as long as the dustproof member can be properly extracted. At this time, the number of grooves provided in the dust-proof member and the installation location (installation interval) are determined according to the number of projections and the installation location (installation interval) of the dust-proof member extraction jig. The location (installation interval) is preferably determined in the same manner.

(Fifth embodiment)
Hereinafter, a fifth embodiment of the ball screw device will be described with reference to the drawings.
FIG. 21 is a diagram illustrating the configuration of a dustproof member and a dustproof member extraction jig in a fifth embodiment of the ball screw device, (a) is a front view of the dustproof member, (b) is a plan view of the dustproof member, (C) is a left side view of the dustproof member, (d) is a rear view of the dustproof member, (e) is a perspective view of the dustproof member extraction jig, and (f) is an enlarged view of the main part of (e). Note that the ball screw device of the present embodiment is different from the third embodiment described above only in the configuration of the dustproof member. Therefore, the same reference numerals are given to the members that overlap or correspond to those of the third embodiment. Therefore, the description is omitted.

  As shown in FIG. 21, the ball screw device 101 of the present embodiment is provided such that the circumferential width of the groove 142 of the dust-proof member 140 is smaller than the circumferential width of the groove 142 in the third embodiment. . The circumferential width of the groove 142 is preferably substantially the same as the circumferential width of the engagement piece 141.

  By adopting such a configuration, the rigidity of the groove 142 can be improved even when the dustproof member 140 requires a certain level of strength. Further, by reducing the width of the groove 142 in this manner, the plurality of protrusions 230 provided on the end surface 201 of the dustproof member extraction jig 200 can be made rectangular as shown in FIG. Further, by making the protrusion 230 of the dustproof member extraction jig 200 rectangular, not only can the manufacturing cost of the dustproof member extraction jig 200 be reduced, but also the yield of the dustproof member extraction jig 200 is improved. Note that, similarly to the above-described embodiment of the dustproof member extraction jig, the distal end portion of the projection 230 having a rectangular shape may be a curved surface 230a (see FIG. 21F).

(Sixth embodiment)
Hereinafter, a sixth embodiment of the ball screw device will be described with reference to the drawings.
22A and 22B are diagrams showing the configuration of a dustproof member in a sixth embodiment of the ball screw device, wherein FIG. 22A is a rear view of the dustproof member, FIG. 22B is a plan view of the dustproof member, and FIG. 22C is a dustproof member. (D) is a sectional view along the axial direction when the dustproof member is incorporated in the ball screw device, and (e) is an enlarged view of the main part of (d). Note that the ball screw device of the present embodiment is also different from the third embodiment described above in terms of the structure of the dustproof member, and therefore, the same reference numerals are given to the members that overlap or correspond to the third embodiment. Therefore, the description is omitted.

As shown in FIG. 22, in the ball screw device 101 of the present embodiment, a plurality of convex portions 143 that are in contact with the inner peripheral surface 120 a of the nut 120 are provided annularly and in pieces on the outer peripheral surface 140 a of the dust-proof member 140. ing.
The plurality of convex portions 143 may be provided at equal intervals on the outer peripheral surface 140a of the dustproof member 140, or may be equally spaced with respect to the central axis O of the dustproof member 140, or may be unevenly spaced. It may be arranged.

The plurality of convex portions 143 are preferably provided with a tightening allowance of 0 to 0.10 mm with respect to the inner peripheral surface 120 a of the nut 120.
As described above, since the plurality of convex portions 143 are provided on the outer peripheral surface 140a of the dust-proof member 140, the dust-proof member 140 can be used even when heat treatment deformation remains or a nut having a relatively low dimensional accuracy grade. It has the effect of making it difficult to move in the circumferential direction.

(Seventh embodiment)
Hereinafter, a seventh embodiment of the ball screw device will be described with reference to the drawings.
FIGS. 23A and 23B are diagrams showing the configuration of the dust-proof member in the seventh embodiment of the ball screw device, wherein FIG. 23A is a left side view of the dust-proof member, FIG. 23B is a rear view of the dust-proof member, and FIG. Sectional drawing in alignment with the axial direction at the time of incorporating a member in a ball screw device, (d) is sectional drawing in alignment with the axial direction at the time of incorporating a dustproof member in a ball screw device in the past. Note that the ball screw device of the present embodiment also differs from the above-described sixth embodiment only in the configuration of the dust-proof member, and therefore, the same reference numerals are given to the members that overlap or correspond to those in the sixth embodiment. Therefore, the description is omitted.

  As shown in FIGS. 23A to 23D, in the ball screw device 101 of this embodiment, the end face 140b facing the insertion direction with respect to the nut 120 in the dustproof member 140 is inserted more than the engagement piece 141. It protrudes in the direction you want. That is, a gap (step) is formed between the end surface 140b and the end 141a of the engagement piece 141 in the insertion direction.

  With such a configuration, even when the dustproof member 140 is installed on the nut 120, the end surface 140 b comes into contact with the end surface 122 a facing the engagement piece 141 of the engagement groove 122 before the engagement piece 141. (See FIG. 23 (c)). Therefore, even when the dust-proof member 140 is vigorously inserted into the nut 120, the engagement piece 141 may be caught on the end surface 122a of the engagement groove 122 facing the engagement piece 141 as shown in FIG. Can be reduced.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed. For example, at least one of the above embodiments can be combined.

DESCRIPTION OF SYMBOLS 1 Ball screw apparatus 2 Screw shaft 3 Ball | bowl 4 Nut 5 Dust-proof member 6 Recessed part 7 Locking part 8 Claw 8a Inclined surface 9 Arm part 12 Inner groove part (locked part)
13 Notch O Central axis of screw shaft, nut, and dustproof member 101 Ball screw device 110 Screw shaft 111 Ball rolling groove 112 Flange 120 Nut 121 Ball rolling groove 122 Engaging groove 130 Ball 140 Dustproof member 141 Engagement Piece 142 Groove 145 Jig 200 Dustproof member extraction jig 210 First member 220 Second member

Claims (10)

In a ball screw device in which a recess is formed at the inner peripheral end of the nut through which the screw shaft passes, and a dustproof member is provided in the recess,
The dust-proof member is made of a cylindrical elastic member into which the screw shaft is inserted, and has at least one protrusion protruding in the outer diameter direction from the outer peripheral surface of the dust-proof member.
The ball screw device according to claim 1, wherein the recess has a groove shape into which the dust-proof member can be fitted, and a locked portion to which the protrusion is locked is provided.   2. The ball screw device according to claim 1, wherein an inclined surface inclined toward the central axis along the direction of the central axis of the dustproof member is formed on the protrusion.   3. The ball screw device according to claim 1, wherein the locked portion includes a groove formed in the recessed portion toward an outer diameter direction. 4. The dust-proof member has an arm portion made of an elastic member extending in the direction of the central axis,
The ball screw device according to claim 1, wherein the protrusion is provided on the arm portion. A cutout portion is formed on the outer peripheral surface of the dustproof member,
The ball screw device according to claim 4, wherein the arm portion is disposed in the notch portion.   The ball according to claim 4 or 5, wherein a distance between the outermost surface of the arm portion and the central axis viewed from the direction of the central axis is larger than a radius of the outer peripheral surface of the dustproof member. Screw device.   The ball screw device according to claim 6, wherein the arm portion has a shape curved toward an outer diameter direction.   One or more grooves are provided in the axial direction on the outer peripheral surface of the dustproof member, and the engagement of the protrusions from the recesses is released by pressing the inner wall of the grooves toward the central axis by the protrusions of the jig. The ball screw device according to claim 1, wherein the ball screw device is provided.   The ball screw device according to claim 8, wherein the groove portions are provided at equal intervals in the circumferential direction.   The ball screw according to any one of claims 1 to 9, wherein a plurality of convex portions that are in contact with the inner peripheral surface of the nut are annularly and fragmentally provided on the outer peripheral surface of the dustproof member. apparatus.

Images