JP2014156929A - Ball screw device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball screw device which easily and properly performs centering of a nut and a fixing member.SOLUTION: A ball screw device includes: a screw shaft 10; a nut 20 through which the screw shaft 10 penetrates, the nut 20 which threadedly engages with the screw shaft 10 through a rolling element B and is installed so as to move in an axial direction of the screw shaft 10; and a fixing member 40. The fixing member 40 is attached to an end surface 20a of the nut 20. A dust-proofing member 60 which prevents foreign objects from intruding into the nut 20 is attached to the fixing member 40. A fitting part 20b which fits into an outer peripheral surface 42a of a flange part 42 of the fixing member 40 is formed on the end surface 20a of the nut 20.

Description

  The present invention relates to a ball screw device.

In the ball screw device, a screw shaft in which a spiral screw groove is formed is inserted into a nut, and the relative movement between the nut and the screw shaft is smoothed by a plurality of balls rolling and circulating in the screw groove.
In such a ball screw device, if foreign matter such as dust or cutting powder enters the ball screw device during operation, it may promote wear on the thread groove surface or cause indentation to cause abnormal vibration or In addition to generating noise and degrading the original accuracy and performance of the ball screw, there are cases where it sometimes breaks.

Therefore, in order to prevent foreign matter from entering the ball screw device, a felt wiper seal or labyrinth seal has been conventionally provided at the nut end, or the entire screw shaft is covered with various covers such as bellows. In general, a method of using them or a method of using them together is used (see, for example, Patent Document 1).
Hereinafter, with reference to FIGS. 5 and 6, a ball screw device of this type in which a labyrinth seal is provided by a fixing member will be described. 5A and 5B are diagrams showing a configuration of a conventional ball screw device, where FIG. 5A is a front view, FIG. 5B is a cross-sectional view taken along line 5b-5b, and FIG. 5C is taken along line 5b-5b of the fixing member. It is sectional drawing. 6A and 6B are diagrams showing another configuration of the conventional ball screw device, where FIG. 6A is a front view, FIG. 6B is a cross-sectional view taken along line 6b-6b, and FIG. It is sectional drawing which follows a 6b line.

  As shown in FIGS. 5 and 6, the conventional ball screw device 100 includes a rod-shaped screw shaft 110 extending in the axial direction, a cylindrical nut 120 through which the screw shaft 110 passes, and an end 120 a of the nut 120. It has the circulation member 130 provided and the fixing member 140 attached to the circulation member 130. The fixed member 140 is attached with a dustproof member 160 that prevents dust from entering the fixed member 140 (in the rolling path). Specifically, the dust-proof member 160 is fixed to the fixing member 140 by the pressing plate 161 by a fixing screw 172 that is screwed into a screw hole provided on the opening side of the fixing member 140 (outside in the axial direction, that is, the left side in FIGS. A labyrinth seal portion is formed between the attachment and dust-proof member 160 and the screw shaft 110. As shown in FIGS. 6B and 6C, the fixing member 140 may accommodate an oil-containing member 150 that supplies lubricating oil to the outer peripheral surface of the screw shaft 110. In any case, the fixing member 140 is attached to the nut 120 by a fixing screw 171.

JP 2008-45632 A

However, in the conventional ball screw device 100 configured as described above, the end surface 120a of the nut 120 and the contact surface 140a of the fixing member 140 are flat, and the contact surface between the circulation member 130 and the fixing member 140 (the nut 120). The surface constituting the end surface 120a is also a flat surface.
Therefore, in the conventional ball screw device 100, when the fixing member 140 is assembled to the end surface 120a of the nut 120, it is necessary to strictly align the nut 120 and the fixing member 140.

Specifically, as shown in FIGS. 7A and 7B, if the core of the fixing member 140 and the core of the nut 120 are assembled and assembled, the dustproof member 160 is attached in the subsequent mounting of the dustproof member 160. Appropriately, that is, the dust-proof member 160 and the screw shaft 110 can be attached concentrically. On the other hand, as shown in FIGS. 7C and 7D, when the core of the fixing member 140 and the core of the nut 120 are assembled in a shifted state, the dustproof member 160 may not be properly assembled. That is, the dust-proof member 160 and the screw shaft 110 are in a misaligned state, and the inner periphery of the dust-proof member 160 and the screw shaft are in a so-called one-sided contact (a state where one side is in contact and the other side is excessively spaced). May cause problems. If the clearance of the labyrinth seal portion is excessive, foreign matter can easily enter the ball screw device 100. Further, when the dust-proof member 160 and the screw shaft 110 come into contact with each other, it causes an increase in operating torque.
Therefore, the present invention has been made paying attention to the above-mentioned problems, and the purpose thereof is to easily and properly fix the nut and the fixing member together, and to make the dustproof member easy. And it is providing the ball screw apparatus which can be attached appropriately.

A ball screw device according to a first aspect of the present invention for solving the above-described problems includes a screw shaft and a screw shaft that passes through the screw shaft and is screwed into the screw shaft via a rolling element. A nut installed movably in the direction;
A ball screw device having a dust-proof member for preventing intrusion of foreign matter into the nut and a fixing member attached to an end of the nut,
The end face of the nut is characterized in that a marking brazing part that fits to the outer peripheral surface of the flange part of the fixing member is formed.
The ball screw device according to claim 2 of the present invention is the ball screw device according to claim 1, wherein the fixing member houses at least an oil-impregnated member for supplying a lubricant to the surface of the screw shaft. It is a feature.
Furthermore, the ball screw device according to claim 3 of the present invention is the ball screw device according to claim 1, wherein the fixing member accommodates a solid lubricating composite member that supplies at least a solid lubricant to the surface of the screw shaft. It is characterized by that.
In particular, according to the configuration of claim 3, it can be used in an environment where oil lubrication is not possible, such as vacuum and high temperature, or in a clean room that dislikes oil.
Furthermore, a ball screw device according to a fourth aspect of the present invention provides:
The composition of the solid lubricant composite member of the fixing member is such that molybdenum disulfide (MoS2) 60 mass% to 80 mass%, at least one of copper (Cu) and nickel (Ni) is 0.1 mass% to 1.8 mass%. %, Graphite 2-7 mass%, tungsten (W) 2-20 mass%, iron (Fe) is contained in the balance, The ball screw device according to claim 3.
The use of the solid lubricant having the specific composition according to claim 4 improves the lubricating performance.
Furthermore, the ball screw device according to claim 5 of the present invention is
5. The ball screw device according to claim 3, wherein a solid lubricant film is provided on a surface of the rolling element.
By applying a solid lubricating film to the rolling element surface in advance, it is possible to maintain a lubricating performance over a long period of time, and to improve the lubricating state at the initial stage of use.

  ADVANTAGE OF THE INVENTION According to this invention, the ball screw apparatus which can perform center alignment with a nut and a fixing member easily and appropriately, and can also perform center alignment with a screw shaft and a dust-proof member easily and appropriately can be provided.

It is a figure which shows the structure in 1st Embodiment of the ball screw apparatus which concerns on this invention, (a) is a front view, (b) is sectional drawing which follows the 1b-1b line. It is a figure which shows the structure of the fixing member in 1st Embodiment of the ball screw apparatus which concerns on this invention, (a) is a front view, (b) is sectional drawing which follows the 2b-2b line of (a). It is a figure which shows the structure in 2nd Embodiment of the ball screw apparatus which concerns on this invention, (a) is a front view, (b) is sectional drawing which follows the 3b-3b line. It is a figure which shows the structure of the fixing member in 2nd Embodiment of the ball screw apparatus which concerns on this invention, (a) is a front view, (b) is sectional drawing which follows the 4b-4b line of (a). It is a figure which shows the structure of the conventional ball screw apparatus, (a) is a front view, (b) is sectional drawing which follows the 5b-5b line, (c) is sectional drawing which follows the 5b-5b line of a fixing member. . It is a figure which shows the structure of the conventional ball screw apparatus, (a) is a front view, (b) is sectional drawing which follows the 6b-6b line, (c) is sectional drawing which follows the 6b-6b line of a fixing member. . It is a figure which shows the problem in the conventional ball screw apparatus, (a) is a front view of the ball screw apparatus appropriately aligned, (b) is 7b-7b of the ball screw apparatus properly aligned. (C) is a front view of a ball screw device that is improperly aligned, and (d) is a cross-sectional view along a line 7d-7d of the ball screw device that is improperly aligned. is there.

Embodiments of a ball screw device according to the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a view showing a configuration of a ball screw device according to a first embodiment of the present invention, in which (a) is a front view and (b) is a cross-sectional view taken along line 1b-1b. Moreover, FIG. 2 is a figure which shows the structure of the fixing member in 1st Embodiment of the ball screw apparatus based on this invention, (a) is a front view, (b) is the 2b-2b line | wire of (a). It is sectional drawing which follows.

[Configuration of Ball Screw Device]
As shown in FIG. 1, the ball screw device 1 according to the present embodiment is provided at a rod-shaped screw shaft 10 extending in the axial direction, a cylindrical nut 20 through which the screw shaft 10 passes, and an end of the nut 20. The circulation member 30 and the fixing member 40 attached to the nut 20 are included. A dustproof member 60 for preventing dust from entering the rolling path is attached to one end surface 40a of the fixing member 40. Here, the fixing member 40 is preferably provided on both end faces of the nut 20. The ball screw device 1 according to the present embodiment is a so-called end deflector type ball screw device in which a circulation member 30 is provided inside the end surface of the nut 20.
The screw shaft 10 has a spiral rolling groove 11 in which a plurality of balls B roll on the outer peripheral surface thereof.

[nut]
On the other hand, the nut 20 is formed in a cylindrical shape with an inner diameter larger than the outer diameter of the screw shaft 10. A rolling groove 21 is formed on the inner peripheral surface of the nut 20 so as to face the rolling groove 11 formed on the outer peripheral surface of the screw shaft 10. A rolling path is formed by the rolling groove 11 of the screw shaft 10 and the rolling groove 21 of the nut 20.
Further, the nut 20 is formed with a through hole 22 penetrating in the axial direction. The through hole 22 forms a circulation path together with the circulation groove 31 formed in the circulation member 30 so as to communicate with the through hole 22 and the rolling path. Thus, in the ball screw device 1, the ball B rolls on the rolling path and circulates in the circulation path, so that the screw shaft 10 and the nut 20 that are screwed through the ball B are relative to each other in the axial direction. Will move.

[Lamp part]
Here, the end face of the nut 20 is formed with a marking wax part 20b that fits to the outer peripheral face 42a of the flange part 42 of the fixing member 40 attached to the end face. The marking wax portion 20 b has an annular shape that extends over the end surface of the nut 20 and the end surface of the circulation member 30. That is, the end surface of the circulation member 30 is also formed following the end surface of the nut 20 in the present embodiment.
That is, the marking wax portion formed by the end surface of the nut 20 and the end surface of the circulation member 30 is formed in a concave shape with the outer edge portion protruding in an annular shape in the direction in which the fixing member 30 is mounted.

[Fixing member]
As shown in FIGS. 2A and 2B, the fixing member 40 has a cylindrical main body 41 having an inner diameter larger than the outer diameter of the screw shaft 10 and an inner peripheral surface of the main body 41. It is comprised from the annular flange part 42 which continues at right angles from the edge part to radial inside (screw shaft 10 direction). In addition, when the fixing member 40 is made of metal, the main body 41 and the flange portion 42 are preferably integrally formed by press molding, and when the fixing member 40 is made of resin, it is integrally formed by injection molding.

Here, at least the outer peripheral surface of the flange portion 42 and at least the inner peripheral surface of the marking wax portion 20b of the nut 20 are formed so as to be coaxial (concentric) with the screw shaft 10.
Further, as shown in FIG. 2B, a pressing plate 51 (FIGS. 1A and 1B) is provided on an end surface 40a opposite to the end surface of the main body 41 of the fixing member 40 where the flange portion 42 is formed. 1 or more), one or more screw holes 43 for screwing the dustproof member rotation stop screw 72 for fixing the dustproof member 60 are formed. The flange portion 42 is formed with one or more screw holes 44 into which a fixing screw 71 for fixing the fixing member 40 to the circulation member 30 (or the nut 20) is screwed.
The fixing member 40 having such a configuration is fixed so that the end surface 40a is positioned outside the ball screw device 1 as shown in FIG. That is, the flange portion 42 is fitted to the marking wax portion 20 b formed at the end portion of the nut 20 and the end portion of the circulation member 30 and fixed by the fixing screw 71.

[Dust-proof material]
The dustproof member 60 is fixed to the fixing member 40 in contact with the outer peripheral surface of the screw shaft 10 (including the rolling groove 11) or with a predetermined interval. Specifically, it is fixed to one end surface 40 a of the fixing member 40 by the pressing plate 51 by a dustproof member rotation stopping screw 72 screwed into the screw hole 43. The shape of the outer periphery of the dustproof member 60 is preferably formed in accordance with the shape of the inner peripheral surface of the fixing member 40, and an annular shape is preferable.
Thus, the outer peripheral surface 42a of the flange portion 42 of the fixing member 40 is fitted to the marking wax portion 20b formed on the end surface of the nut 20, so that the nut 20 and the fixing member 40 can be easily centered. It can be done properly.
Moreover, the dustproof member 60 attached to the end surface 40a of the fixing member 40 is also normally attached, and the problem due to inadequate centering can be prevented beforehand.

(Second Embodiment)
3A and 3B are diagrams showing a configuration of a ball screw device according to a second embodiment of the present invention, in which FIG. 3A is a front view and FIG. 3B is a cross-sectional view along the axial direction. FIGS. 4A and 4B are diagrams showing the configuration of the fixing member in the second embodiment of the ball screw device according to the present invention. FIG. 4A is a front view, and FIG. 4B is a line 4b-4b in FIG. It is sectional drawing which follows.

[Configuration of Ball Screw Device]
As shown in FIG. 3, the ball screw device 1 of the present embodiment is provided at a rod-shaped screw shaft 10 extending in the axial direction, a cylindrical nut 20 through which the screw shaft 10 passes, and an end of the nut 20. The circulation member 30 and the fixing member 40 attached to the nut 20 are included. The fixing member 40 incorporates and is fixed with an oil-containing member 50 that supplies lubricating oil to the outer peripheral surface 10 a of the screw shaft 10. A dustproof member 60 is attached to one end face of the fixing member 40 to prevent dust from entering the rolling path. Here, the fixing member 40 is preferably provided on both end faces of the nut 20. The ball screw device 1 according to this embodiment is a so-called end deflector type ball screw device in which a circulation member 30 is provided inside an end surface portion of a nut 20.
The screw shaft 10 has a spiral rolling groove 11 in which a plurality of balls B roll on the outer peripheral surface 10a.

[nut]
On the other hand, the nut 20 is formed in a cylindrical shape with an inner diameter larger than the outer diameter of the screw shaft 10. A rolling groove 21 is formed on the inner peripheral surface of the nut 20 so as to face the rolling groove 11 formed on the outer peripheral surface of the screw shaft 10. A rolling path is formed by the rolling groove 11 of the screw shaft 10 and the rolling groove 21 of the nut 20.
Further, the nut 20 is formed with a through hole 22 penetrating in the axial direction. The through hole 22 forms a circulation path together with the circulation groove 31 formed in the circulation member 30 so as to communicate with the through hole 22 and the rolling path. Thus, in the ball screw device 1, the ball B circulates in the rolling path and the circulation path, whereby the screw shaft 10 and the nut 20 that are screwed together via the ball B are relatively moved in the axial direction. Become.

[Lamp part]
Here, the end face of the nut 20 is formed with a marking wax part 20b that fits to the outer peripheral face 42a of the flange part 42 of the fixing member 40 attached to the end face. The marking wax portion 20 b has an annular shape that extends along the end surface of the nut 20 and the end surface of the circulation member 30 together with the recess 30 a provided on the end surface of the circulation member 30. That is, the end surface having the marking part 20b is formed by the nut 20 and the circulation member 30 in the present embodiment.

[Fixing member]
As shown in FIGS. 4A and 4B, the fixing member 40 includes a cylindrical main body 41 and a radially inward direction from the end along the inner peripheral surface of the main body 41 (in the direction of the screw shaft 10). ) And an annular flange portion 42 continuous at a right angle. Further, the oil-retaining members 80 and 80 having a ring shape are accommodated in the inner periphery thereof. The oil retaining members 80 and 80 are fixed to the fixing member 40 by a set screw 73. The flange part 42 of the fixing member 40 is formed so as to be fitted to the marking part 20b of the nut 20, and the outer peripheral surface 42a of the flange part 42 of the fixing member 40 is fitted to the marking part 20b. When the screw shaft 10 is used as a reference, the nut 20 and the fixing member 40 are formed so as to be coaxial with the screw shaft 10.

Further, as shown in FIG. 3B, a screw hole 43 into which a dustproof member rotation stop screw 72 for fixing the dustproof member 60 is fixed to the outer end surface of the fixing member 40 via a pressing plate 61. One or more are formed. The flange portion 42 is formed with one or more screw holes 44 into which a fixing screw 71 for fixing the fixing member 40 to the circulation member 30 (or the nut 20) is screwed.
As shown in FIG. 3B, the fixing member 40 having such a configuration has the flange portion 42 fitted to the marking portion 20 b formed by the end portion of the nut 20 and the end portion of the circulation member 30. And fixed with a fixing screw 71.

[Oil-impregnated member and solid lubricating composite member]
As shown in FIGS. 3B and 4B, the oil retaining member 80 is fixed to the fixing member 40 by an oil retaining member rotation stopping screw 73 that is screwed into a screw hole 45 formed in the main body 41 of the fixing member 40. It is installed inside. The oil-containing member 80 is made of, for example, a material formed in a ring shape that absorbs and holds lubricating oil, and supplies a lubricant to the surface of the screw shaft 10 to exhibit appropriate lubricity. Note that the oil-containing member 80 may be divided into two or more with a gap as shown in FIG.

  Further, by using a solid lubricating composite member in place of the oil-containing member 80, it can be used in an environment where oil lubrication such as vacuum or high temperature cannot be performed, or in a clean room that dislikes oil. Further, the composition of the solid lubricating composite member is molybdenum disulfide (MoS2) 60 mass% to 80 mass%, at least one of copper (Cu) and nickel (Ni) is 0.1 mass% to 1.8 mass%, graphite When 2 to 7% by mass, tungsten (W) 2 to 20% by mass, and the balance containing iron (Fe), the strength can withstand the fixation, and smooth sliding can be achieved.

  Furthermore, by applying a solid lubricating film to the surface of the ball B, which is a rolling element, the initial lubrication is provided and the durability of the ball screw device 1 is further improved by the lubricating effect of the solid lubricating film itself, thereby extending the life. It becomes possible to do. The material component of the solid lubricant film is desirably the same material component as that of the solid lubricant composite member, which can contribute to smoother sliding.

[Dust-proof material]
The dustproof member 60 is fixed to the fixing member 40 in contact with the outer peripheral surface 10a (including the rolling groove 11) of the screw shaft 10 or with a predetermined interval. Specifically, it is fixed to the outer end surface of the fixing member 40 via the pressing plate 51 by a dustproof member rotation stopping screw 72 screwed into the screw hole 43. The shape of the dustproof member 60 is preferably formed in accordance with the shape of the inner peripheral surface of the fixing member 40, and an annular shape is preferable.
As described above, the outer peripheral surface 42 a of the flange portion 42 of the fixing member 40 is fitted to the end brazing portion 20 b formed by the end surface of the nut 20 and the circulation member 30, whereby the core between the nut 20 and the fixing member 40 is formed. It can be easily and properly carried out.
In addition, the dustproof member 60 attached to the end surface of the fixing member 40 is also normally attached, and problems due to inadequate centering can be prevented.

As described above, according to the present invention, it is possible to provide a ball screw device that can easily and properly center the nut and the fixing member.
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.

DESCRIPTION OF SYMBOLS 1 Ball screw 10 Screw shaft 20 Nut 20a End part 21 Rolling groove 22 Through hole 30 Circulating member 40 Fixing member 40a End surface 41 Main body part 42 Flange part 42a Outer peripheral surface 43 Screw hole 44 Screw hole 45 Screw hole 60 Dustproof member 71 Fixing screw 72 Dust proof member anti-rotation screw B Ball (rolling element)

Claims (5)

A screw shaft, and a nut that penetrates the screw shaft and is screwed to the screw shaft via a rolling element and is movable in the axial direction of the screw shaft;
A ball screw device having a dust-proof member for preventing intrusion of foreign matter into the nut and a fixing member attached to an end face of the nut,
The ball screw device according to claim 1, wherein an end face of the nut is formed with a marking wax portion that fits to an outer peripheral surface of the flange portion of the fixing member.   The ball screw device according to claim 1, wherein the fixing member accommodates an oil-containing member that supplies a lubricant to a surface of the screw shaft.   The ball screw device according to claim 1, wherein the fixing member accommodates a solid lubrication composite member that supplies a solid lubricant to the surface of the screw shaft.   The composition of the solid lubricant composite member of the fixing member is such that molybdenum disulfide (MoS2) 60 mass% to 80 mass%, at least one of copper (Cu) and nickel (Ni) is 0.1 mass% to 1.8 mass%. %, Graphite 2-7 mass%, tungsten (W) 2-20 mass%, iron (Fe) is contained in the remainder, The ball screw apparatus of Claim 3 characterized by the above-mentioned.   The ball screw device according to claim 3 or 4, wherein a solid lubricating film is applied to the surface of the rolling element.

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