JP2019049317A - Ball spline mechanism - Google Patents

Abstract

To provide a ball screw mechanism capable of being effectively lubricated.SOLUTION: A ball spline mechanism includes a nut 20 movable along a screw shaft 10 and provided with an oil guide hole 23 penetrated to an inner surface 21 from an outer surface 22, a linear bearing unit 30 disposed between the shaft 10 and the nut 20, a bearing ring 40 disposed while surrounding the nut 20 and provided with an oil injection hole 43 penetrated from an outer face 42 to an inner face 41, and an oil flow channel formation member 50 having a fixed position portion 51 disposed between the bearing ring 40 and the nut 20, and an oil lead-in passage 521 corresponded to the oil injection hole 43, and provided with an oil storage chamber 513 opened toward an outer face 22 and communicated to the oil lead-in passage 521, on the fixed position portion 51, and an oil injection passage communicated from the outer face 42 to the inner surface 21, is formed by the oil injection hole 43, the oil lead-in passage 521, the oil storage chamber 513 and the oil guide hole 23.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power transmission mechanism of a processing machine, and more particularly to a ball screw mechanism.

  Patent document 1 is mentioned as an example of the conventional ball screw. The ball screw comprises a screw shaft ("screw shaft 1" in Patent Document 1, the same reference numerals in parentheses being the same in the following), a ball nut (ball nut 2) surrounding the outer periphery of the screw shaft, a screw shaft and a ball nut A first ball unit (balls 3) disposed between the two, an outer ring (bearing outer race 18) surrounding the outer periphery of the ball nut, and a pair of second balls each disposed between the ball nut and the outer ring And units (rolling elements 16). The outer ring is provided with a first oil supply hole 40 along the radial direction. The ball nut is formed to extend from the outer peripheral surface to the inner peripheral surface (inner peripheral surface 2b), the outer peripheral surface (outer peripheral surface 2c), and the outer peripheral surface in the circumferential direction of the recess and is in communication with the first oiling hole A second oiling, which is formed in a plurality at equal angles in the circumferential direction with the oil reservoir groove (annular oil supplying groove 42), communicates with the oil reservoir groove and penetrates the ball nut from the outer peripheral surface to the inner peripheral surface. It has a hole (second oil supplying hole 43).

  When oiling between the screw shaft and the ball nut, oil is injected from the first oiling hole. However, the injected oil does not flow into the space between the screw shaft and the ball nut via the second oil supply hole after filling the oil storage groove. For this reason, excessive injection of oil is likely to occur, and the amount of oil actually reaching the space between the screw shaft and the ball nut is small with respect to the amount of injected oil, resulting in the problem that the utilization efficiency of oil is poor. Due to this problem, the above-mentioned conventional ball screw has difficulty in lubricating the first and second ball units.

  Moreover, patent document 2 is also mentioned as an example of the conventional ball screw. Also in this ball screw, a screw shaft (symbol 1 in Patent Document 2, the same reference numeral in parentheses is the same in the following), a nut (2) inserted into the screw shaft, and a screw shaft and a nut disposed between the screw shaft and the nut 1 rolling unit (6), an outer ring (4, 5) which is provided with a lubrication hole (43) and is arranged to surround the outer periphery of the nut, and two arranged between the nut and the outer ring And a second rolling unit (7). In the nut, two protrusions (8) are formed on the outer peripheral surface, oil holes (B1, B2) are provided between the protrusions, and each second rolling unit (7) is provided with an oil hole (B1, B2). It is arranged to be separated by these projections from B2).

  In this conventional ball screw, the oil adheres to the second rolling unit because the projections for separating the respective oil holes and the respective second rolling units are formed on the outer peripheral surface of the nut as described above. It is prevented that it passes too much.

U.S. Pat. No. 5,809,838 Taiwan Patent No. I444542

  However, in the conventional ball screw described above, the control of the amount of oil attached to the second rolling unit becomes difficult due to the presence of the projection, and the amount actually attached becomes too small to exhibit sufficient lubricating effect. It tends to happen.

  Therefore, an object of the present invention is to provide a ball screw mechanism that can be lubricated so as to give each ball in a ball screw a lubricating effect more effective than before.

As means for achieving the above object, the present invention provides the following ball screw mechanism.
That is, a screw shaft extending along a predetermined axis, the outer peripheral surface, and a plurality of pairs of first ball rolling grooves each formed to be recessed from the outer peripheral surface and extending parallel to the axis With a screw shaft,
A nut provided to surround the screw shaft and movable along the screw shaft, the nut having an inner surface facing the outer circumferential surface of the screw shaft and an outer surface opposite to the inner surface. Further, a plurality of oil guide holes penetrating from the outer surface to the inner surface, and a plurality of pairs of second ball rotations formed so as to be respectively recessed from the inner surface and facing the first ball rolling groove A moving groove, at least one third ball rolling groove formed to be recessed from the outer surface and extending to surround the axis, and formed to be recessed from the outer surface, and the third ball rolling A nut provided with at least one communicating groove in communication with the groove;
A linear bearing unit disposed between the outer circumferential surface of the screw shaft and the inner surface of the nut for guiding the movement of the nut along the screw shaft, the first ball holder; The first ball rolling groove and the second ball rolling groove, which have a plurality of sets of first balls respectively held by one ball holder, and the first balls of each set correspond to each other A linear bearing unit fitted with the
A bearing ring arranged to surround the nut and rotatable about the axis, the bearing ring having an inner surface facing the outer surface of the nut and an outer surface opposite to the inner surface, and the outer surface And an oil injection hole penetrating from the inner surface to the inner surface, and at least one fourth ball rolling groove recessed from the inner surface so as to surround the axis in correspondence with the third ball rolling groove. With the bearing ring provided,
The positioning portion disposed between the inner surface of the bearing ring and the outer surface of the nut, and the oil introduction passage corresponding to the oil injection hole, and the positioning portion includes the outer surface of the nut An oil flow path forming member provided with an oil storage chamber which is open toward the end and in communication with the oil introduction path;
A circumferential bearing unit disposed between the inner surface of the bearing ring and the outer surface of the nut for enabling rotation of the bearing ring relative to the nut about the axis, the second bearing unit comprising: A ball holder and a plurality of second balls respectively held by the second ball holder, wherein each of the second balls includes the third ball rolling groove and the fourth ball rotation A circumferential bearing unit fitted in the moving groove,
Forming an oil injection path communicating the outer surface of the bearing ring to the inner surface of the nut by the oil injection hole, the oil introduction passage, the oil storage chamber, and any one of the oil guide holes; To provide a ball screw mechanism.

  According to the above-mentioned means, the oil which communicates from the outer surface of the bearing ring to the inner surface of the nut by the oil injection hole, the oil introduction passage, the oil storage chamber, and any one oil guide hole Since the injection path is formed, if the oil injection hole is lubricated, the oil can reach the linear bearing unit, that is, the internal members can be directly lubricated from the outside, and the oil Since the oil is temporarily stored in the oil storage chamber and then flows into the oil guide hole 23, excessive lubrication can be prevented.

It is an assembly perspective view showing one embodiment of a ball screw mechanism concerning the present invention. It is an exploded perspective view showing the above-mentioned embodiment. It is sectional drawing along the III-III line of FIG. It is sectional drawing along the IV-IV line of FIG.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  1 to 4 show an embodiment of a ball screw mechanism according to the present invention. Among these, FIG. 1 is a perspective view showing the assembled state of the ball screw mechanism, FIG. 2 is a perspective view showing the disassembled state, and FIG. 3 shows a cross section taken along line III-III in FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG.

  As shown (mainly in FIG. 2), the ball screw mechanism comprises a screw shaft 10, a nut 20, a linear bearing unit 30, a bearing ring 40, an oil passage forming member 50, and a circumferential bearing unit 60. Each configuration will be described in detail below.

  The screw shaft 10 extends along a predetermined axis L, and is formed on the outer circumferential surface 11 so as to be recessed from the outer circumferential surface 11 and extends parallel to the axis L. A plurality of 12 is provided. In the present embodiment, as shown in FIG. 4, a pair of first ball rolling grooves 12 provided close to each other is provided at an angular interval of 120 degrees around the axis L. Therefore, three pairs (a total of six) of first ball rolling grooves 12 are provided.

  The nut 20 is provided so as to be movable relative to the screw shaft 10 in a direction parallel to the axis L such that the screw shaft 10 is passed therethrough. Further, the nut 20 has an inner surface 21 facing the outer peripheral surface 11 of the screw shaft 10 and surrounding the outer peripheral surface 11, and an outer surface 22 opposite to the inner surface 21.

  Furthermore, the nut 20 is formed so as to be recessed respectively from the inner surface 21 with a plurality of oil guide holes 23 penetrating from the outer surface 22 to the inner surface 21 respectively, and the first ball rolling groove of each pair of screw shafts 10 A plurality of pairs of second ball rolling grooves 24 extending in parallel with the axis L to correspond to 12 and two first balls formed so as to be recessed from the outer surface 22 and extending in the circumferential direction around the axis L A ball rolling groove 25 is provided, and at least one communication groove 26 is formed so as to be recessed from the outer surface 22 and extends so as to be substantially parallel to the axis L.

  As shown in FIG. 2, in the present embodiment, the two third ball rolling grooves 25 are provided to be spaced apart from each other in the direction parallel to the axis L, and these third ball rolling Each oil guide hole 23 is provided between the moving grooves 25. Further, there are a plurality of communication grooves 26 which do not overlap with the oil guide holes 23, and the two third ball rolling grooves 25 are communicated with each other.

  As shown in FIG. 4, the plurality of oil guide holes 23 are arranged side by side with each other in a pair, and in the present embodiment, three sets of oil guide holes 23 are axial lines It is arranged at an angular interval of 120 degrees around L.

  In the present embodiment, as described above, two third ball rolling grooves 25 are provided, and each communication groove 26 is provided so as to connect between the two third ball rolling grooves 25. Not limited to this, at least one third ball rolling groove 25 may be provided. The communication groove 26 is a groove provided for transmitting oil to the third ball rolling groove 25. For example, when only one third ball rolling groove 25 is provided, the communication groove 26 is one third ball It may be provided in communication with the rolling groove 25.

  The linear bearing unit 30 is disposed between the outer circumferential surface 11 of the screw shaft 10 and the inner surface 21 of the nut 20, and the above-described nut 20 slides linearly with respect to the screw shaft 10 in a direction parallel to the axis L. Guide to help you The linear bearing unit 30 has a first ball holder 31 and a plurality of sets of first balls 32 held by the first ball holder 31. The first balls 32 of each set are aligned and fit in the corresponding first ball rolling grooves 12 and second ball rolling grooves 24 as shown in FIG.

  The bearing ring 40 is disposed to rotatably surround the nut 20 in the circumferential direction around the axis L, and has an inner surface 41 opposite to the outer surface 22 of the nut 20 and an outer surface 42 opposite to the inner surface 41. Further, the bearing ring 40 has an oil injection hole 43 penetrating from the outer surface 42 to the inner surface 41, and two fourth ball rolling grooves 45 formed to be depressed from the inner surface 41 and to surround the axis L, respectively. Is provided. Each fourth ball rolling groove 45 is opposed to each third ball rolling groove 25 as shown in FIG.

  The oil passage forming member 50 is disposed between the two third ball rolling grooves 25 between the inner surface 41 of the bearing ring 40 and the outer surface 22 of the nut 20, and has a cross section along the circumferential direction Has a U-shaped (see FIG. 4) localization part 51 and a tubular part 52 connected to the localization part 51.

  The localization portion 51 is in contact with the outer surface 22 of the outer surface 512 which is formed as an arc-shaped convex surface so as to abut on the inner surface 41 of the bearing ring 40 and the outer surface 22 of the nut 20. It has an inner side surface 511 formed in an arc-shaped concave surface, and is positioned between the inner surface 41 and the outer surface 22. Further, on the inner side surface 511 of the oriented portion 51, an oil storage chamber 513 which is formed so as to be recessed from the inner side surface 511 and opens toward the outer surface 22 of the nut 20 is provided.

  The tubular portion 52 is inserted into the oil injection hole 43 of the bearing ring 40 and defines an oil introduction passage 521 communicating with the oil storage chamber 513. As shown in FIG. 4, the oil injection hole 43, the oil introduction passage 521, the oil storage chamber 513, and any one oil guide hole 23 extend from the outer surface 42 of the bearing ring 40 to the inner surface 21 of the nut 20. A communicating oil injection path is formed.

  As shown in FIG. 4, the length of the oil storage chamber 513 in the circumferential direction centering on the axis L is equal to or greater than the maximum interval in the circumferential direction of the two oil guide holes 23 of each set. It is formed as.

  When the bearing ring 40 rotates relative to the nut 20, the oil flow path forming member 50 also rotates relative to the nut 20 in conjunction with the bearing ring 40, and the inner side surface 511 of the orienting portion 51 is the outer surface of the nut 20 Slide 22 Then, when the oil flow path forming member 50 rotates and comes over the opening of the oil guide hole 23 in the outer surface 22 of the nut 20, the oil storage chamber 513 and the oil guide hole 23 communicate with each other. That is, the above-described oil injection path is formed.

  In addition, in order to soften the friction when the oil flow path forming member 50 slides with respect to the nut 20, the localization portion 51 is preferably made of a material having a low coefficient of friction or a porous material. As an example, it can be made of plastic or felt having a coefficient of friction of 0.2 to 0.3.

  The circumferential bearing unit 60 is disposed between the inner surface 41 of the bearing ring 40 and the outer surface 22 of the nut 20 to allow circumferential rotation of the bearing ring 40 about the axis L relative to the nut 20. There is. The circumferential bearing unit 60 has a second ball holder 61 and a plurality of second balls 62 respectively held by the second ball holder 61. The plurality of second balls 62 are respectively fitted to the third ball rolling groove 25 of the nut 20 and the fourth ball rolling groove 45 of the bearing ring 40.

  By providing the above configuration, the ball screw mechanism allows the user to apply oil or grease (hereinafter referred to as oil or the like) to the outer surface 42 of the bearing ring 40, as indicated by arrows in FIG. When injected into the exposed oil injection hole 43, the oil flows into the oil storage chamber 513 via the oil injection hole 43 and the oil introduction passage 521.

  And, as described above, when the oil flow path forming member 50 comes over the opening of the oil guide hole 23 in the process of the oil flow path forming member 50 rotating with the bearing ring 40 The two oil guide holes 23 communicate with each other to form the above-mentioned oil injection path. As a result, oil or the like in the oil storage chamber 513 flows to the oil guide hole 23, reaches the linear bearing unit 30 between the screw shaft 10 and the nut 20, and the linear bearing unit 30 is lubricated. Therefore, the linear movement of the nut 20 with respect to the screw shaft 10 becomes smooth.

  Further, when the oil flow path forming member 50 is not positioned above the opening of the oil guide hole 23 in the process of the oil flow path forming member 50 rotating with the bearing ring 40, the oil storage chamber 513 is any oil guide hole 23. Since it does not communicate, ie, the above-mentioned oil injection path is interrupted, oil etc. do not flow into the oil guide hole 23. Thus, oil and the like are prevented from flowing excessively to the linear bearing unit 30.

  Thus, in the present invention, oil and the like are injected from the outside of the outer bearing ring 40 by forming the above-described oil injection path, and the inner linear bearing unit 30 is lubricated. It becomes possible. Furthermore, when the bearing ring 40 rotates, the oil storage chamber 513 of the oil flow path forming member 50 and the oil guide hole 23 of the nut 20 become communicated or disconnected by the rotation of the oil flow path forming member 50. Lubrication is prevented, and appropriate lubrication of the linear bearing unit 30 is possible.

  If the localization portion 51 of the oil flow path forming member 50 is made of a material having a low coefficient of friction or a porous material as in the present embodiment, the localization portion 51 when the oil flow path forming member 50 rotates. Abrasion between the inner surface 511 of the second embodiment and the outer surface 22 of the nut 20 can be reduced, and the above-mentioned oil injection passage is sealed.

  Further, as described above, since the two third ball rolling grooves 25 communicate with each other on the outer surface 22 of the nut 20 through the plurality of communication grooves 26, oil or the like is injected from the oil injection hole 43 After flowing into the oil storage chamber 513, when the oil flow path forming member 50 comes on any one communication groove 26 in the process of rotating with the bearing ring 40, oil etc. circulates through the communication groove 26. As it flows into both sides of the direction bearing unit 60, the plurality of second balls 62 can be lubricated.

  As described above, according to the ball screw mechanism according to the present invention, it is possible to lubricate the linear bearing unit 30 and the circumferential bearing unit 60 effectively with a simple structure as in the above embodiment. It becomes possible.

  As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the summary.

10 screw shaft 11 outer peripheral surface 12 first ball rolling groove 20 nut 21 inner surface 22 outer surface 23 oil guide hole 24 second ball rolling groove 25 third ball rolling groove 26 communication groove 30 linear bearing unit 31 First ball holder 32 first ball 40 bearing ring 41 inner surface 42 outer surface 43 oil injection hole 45 fourth ball rolling groove 50 oil flow path forming member 51 localization portion 511 inner side surface 512 outer side surface 513 oil storage chamber 52 tubular Part 521 Oil introduction path 60 circumferential bearing unit 61 second ball holder 62 second ball

The present invention relates to a power transmission mechanism of a processing machine, and more particularly to a ball spline mechanism.

  Patent document 1 is mentioned as an example of the conventional ball screw. The ball screw comprises a screw shaft ("screw shaft 1" in Patent Document 1, the same reference numerals in parentheses being the same in the following), a ball nut (ball nut 2) surrounding the outer periphery of the screw shaft, a screw shaft and a ball nut A first ball unit (balls 3) disposed between the two, an outer ring (bearing outer race 18) surrounding the outer periphery of the ball nut, and a pair of second balls each disposed between the ball nut and the outer ring And units (rolling elements 16). The outer ring is provided with a first oil supply hole 40 along the radial direction. The ball nut is formed to extend from the outer peripheral surface to the inner peripheral surface (inner peripheral surface 2b), the outer peripheral surface (outer peripheral surface 2c), and the outer peripheral surface in the circumferential direction of the recess and is in communication with the first oiling hole A second oiling, which is formed in a plurality at equal angles in the circumferential direction with the oil reservoir groove (annular oil supplying groove 42), communicates with the oil reservoir groove and penetrates the ball nut from the outer peripheral surface to the inner peripheral surface. It has a hole (second oil supplying hole 43).

  When oiling between the screw shaft and the ball nut, oil is injected from the first oiling hole. However, the injected oil does not flow into the space between the screw shaft and the ball nut via the second oil supply hole after filling the oil storage groove. For this reason, excessive injection of oil is likely to occur, and the amount of oil actually reaching the space between the screw shaft and the ball nut is small with respect to the amount of injected oil, resulting in the problem that the utilization efficiency of oil is poor. Due to this problem, the above-mentioned conventional ball screw has difficulty in lubricating the first and second ball units.

  Moreover, patent document 2 is also mentioned as an example of the conventional ball screw. Also in this ball screw, a screw shaft (symbol 1 in Patent Document 2, the same reference numeral in parentheses is the same in the following), a nut (2) inserted into the screw shaft, and a screw shaft and a nut disposed between the screw shaft and the nut 1 rolling unit (6), an outer ring (4, 5) which is provided with a lubrication hole (43) and is arranged to surround the outer periphery of the nut, and two arranged between the nut and the outer ring And a second rolling unit (7). In the nut, two protrusions (8) are formed on the outer peripheral surface, oil holes (B1, B2) are provided between the protrusions, and each second rolling unit (7) is provided with an oil hole (B1, B2). It is arranged to be separated by these projections from B2).

  In this conventional ball screw, the oil adheres to the second rolling unit because the projections for separating the respective oil holes and the respective second rolling units are formed on the outer peripheral surface of the nut as described above. It is prevented that it passes too much.

U.S. Pat. No. 5,809,838 Taiwan Patent No. I444542

  However, in the conventional ball screw described above, the control of the amount of oil attached to the second rolling unit becomes difficult due to the presence of the projection, and the amount actually attached becomes too small to exhibit sufficient lubricating effect. It tends to happen.

Therefore, an object of the present invention is to provide a ball spline mechanism that can be lubricated so as to provide a more effective lubricating effect to each ball in the ball spline than before.

As means for achieving the above object, the present invention provides the following ball spline mechanism.
That is, a spline shaft extending along a predetermined axis, the outer peripheral surface, and a plurality of pairs of first ball rolling grooves each formed to be recessed from the outer peripheral surface and extending parallel to the axis. With a spline shaft,
A nut can be moved along the spline shaft is provided so as to surround said spline shaft, said outer circumferential surface opposed to the inner surface of said spline shaft, and an opposite face in which the outer surface of the inner surface Further, a plurality of oil guide holes penetrating from the outer surface to the inner surface, and a plurality of pairs of second ball rotations formed so as to be respectively recessed from the inner surface and facing the first ball rolling groove A moving groove, at least one third ball rolling groove formed to be recessed from the outer surface and extending to surround the axis, and formed to be recessed from the outer surface, and the third ball rolling A nut provided with at least one communicating groove in communication with the groove;
A linear bearing unit disposed between the outer peripheral surface of the spline shaft and the inner surface of the nut for guiding the movement of the nut along the spline shaft, the first ball holder; The first ball rolling groove and the second ball rolling groove, which have a plurality of sets of first balls respectively held by one ball holder, and the first balls of each set correspond to each other A linear bearing unit fitted with the
A bearing ring arranged to surround the nut and rotatable about the axis, the bearing ring having an inner surface facing the outer surface of the nut and an outer surface opposite to the inner surface, and the outer surface And an oil injection hole penetrating from the inner surface to the inner surface, and at least one fourth ball rolling groove recessed from the inner surface so as to surround the axis in correspondence with the third ball rolling groove. With the bearing ring provided,
The positioning portion disposed between the inner surface of the bearing ring and the outer surface of the nut, and the oil introduction passage corresponding to the oil injection hole, and the positioning portion includes the outer surface of the nut An oil flow path forming member provided with an oil storage chamber which is open toward the end and in communication with the oil introduction path;
A circumferential bearing unit disposed between the inner surface of the bearing ring and the outer surface of the nut for enabling rotation of the bearing ring relative to the nut about the axis, the second bearing unit comprising: A ball holder and a plurality of second balls respectively held by the second ball holder, wherein each of the second balls includes the third ball rolling groove and the fourth ball rotation A circumferential bearing unit fitted in the moving groove,
Forming an oil injection path communicating the outer surface of the bearing ring to the inner surface of the nut by the oil injection hole, the oil introduction passage, the oil storage chamber, and any one of the oil guide holes; To provide a ball spline mechanism.

  According to the above-mentioned means, the oil which communicates from the outer surface of the bearing ring to the inner surface of the nut by the oil injection hole, the oil introduction passage, the oil storage chamber, and any one oil guide hole Since the injection path is formed, if the oil injection hole is lubricated, the oil can reach the linear bearing unit, that is, the internal members can be directly lubricated from the outside, and the oil Since the oil is temporarily stored in the oil storage chamber and then flows into the oil guide hole 23, excessive lubrication can be prevented.

It is an assembly perspective view showing one embodiment of a ball spline mechanism concerning the present invention. It is an exploded perspective view showing the above-mentioned embodiment. It is sectional drawing along the III-III line of FIG. It is sectional drawing along the IV-IV line of FIG.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

One embodiment of a ball spline mechanism according to the present invention is shown in FIGS. Among these, FIG. 1 is a perspective view showing the assembled state of the ball spline mechanism, FIG. 2 is a perspective view showing the disassembled state, and FIG. 3 shows a cross section taken along line III-III in FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG.

As shown (see mainly FIG. 2), the ball spline mechanism comprises a spline shaft 10, a nut 20, a linear bearing unit 30, a bearing ring 40, an oil flow path forming member 50, and a circumferential bearing unit 60. Each configuration will be described in detail below.

The spline shaft 10 extends along a predetermined axis L, and is formed on the outer peripheral surface 11 so as to be recessed from the outer peripheral surface 11 and extends parallel to the axis L. A plurality of 12 is provided. In the present embodiment, as shown in FIG. 4, a pair of first ball rolling grooves 12 provided close to each other is provided at an angular interval of 120 degrees around the axis L. Therefore, three pairs (a total of six) of first ball rolling grooves 12 are provided.

The nut 20 is provided movably with respect to the spline shaft 10 in a direction parallel to the axis L so that the spline shaft 10 can be passed therethrough. Further, the nut 20 has an inner surface 21 facing the outer peripheral surface 11 of the spline shaft 10 and surrounding the outer peripheral surface 11, and an outer surface 22 opposite to the inner surface 21.

Furthermore, the nut 20 is formed so as to be recessed respectively from the inner surface 21 with a plurality of oil guide holes 23 penetrating from the outer surface 22 to the inner surface 21 respectively, and the first ball rolling groove of each pair of the spline shaft 10 A plurality of pairs of second ball rolling grooves 24 extending in parallel with the axis L to correspond to 12 and two first balls formed so as to be recessed from the outer surface 22 and extending in the circumferential direction around the axis L A ball rolling groove 25 is provided, and at least one communication groove 26 is formed so as to be recessed from the outer surface 22 and extends so as to be substantially parallel to the axis L.

  As shown in FIG. 2, in the present embodiment, the two third ball rolling grooves 25 are provided to be spaced apart from each other in the direction parallel to the axis L, and these third ball rolling Each oil guide hole 23 is provided between the moving grooves 25. Further, there are a plurality of communication grooves 26 which do not overlap with the oil guide holes 23, and the two third ball rolling grooves 25 are communicated with each other.

  As shown in FIG. 4, the plurality of oil guide holes 23 are arranged side by side with each other in a pair, and in the present embodiment, three sets of oil guide holes 23 are axial lines It is arranged at an angular interval of 120 degrees around L.

  In the present embodiment, as described above, two third ball rolling grooves 25 are provided, and each communication groove 26 is provided so as to connect between the two third ball rolling grooves 25. Not limited to this, at least one third ball rolling groove 25 may be provided. The communication groove 26 is a groove provided for transmitting oil to the third ball rolling groove 25. For example, when only one third ball rolling groove 25 is provided, the communication groove 26 is one third ball It may be provided in communication with the rolling groove 25.

The linear bearing unit 30 is disposed between the outer peripheral surface 11 of the spline shaft 10 and the inner surface 21 of the nut 20, and the aforementioned nut 20 slides linearly with respect to the spline shaft 10 in a direction parallel to the axis L Guide to help you The linear bearing unit 30 has a first ball holder 31 and a plurality of sets of first balls 32 held by the first ball holder 31. The first balls 32 of each set are aligned and fit in the corresponding first ball rolling grooves 12 and second ball rolling grooves 24 as shown in FIG.

  The bearing ring 40 is disposed to rotatably surround the nut 20 in the circumferential direction around the axis L, and has an inner surface 41 opposite to the outer surface 22 of the nut 20 and an outer surface 42 opposite to the inner surface 41. Further, the bearing ring 40 has an oil injection hole 43 penetrating from the outer surface 42 to the inner surface 41, and two fourth ball rolling grooves 45 formed to be depressed from the inner surface 41 and to surround the axis L, respectively. Is provided. Each fourth ball rolling groove 45 is opposed to each third ball rolling groove 25 as shown in FIG.

  The oil passage forming member 50 is disposed between the two third ball rolling grooves 25 between the inner surface 41 of the bearing ring 40 and the outer surface 22 of the nut 20, and has a cross section along the circumferential direction Has a U-shaped (see FIG. 4) localization part 51 and a tubular part 52 connected to the localization part 51.

  The localization portion 51 is in contact with the outer surface 22 of the outer surface 512 which is formed as an arc-shaped convex surface so as to abut on the inner surface 41 of the bearing ring 40 and the outer surface 22 of the nut 20. It has an inner side surface 511 formed in an arc-shaped concave surface, and is positioned between the inner surface 41 and the outer surface 22. Further, on the inner side surface 511 of the oriented portion 51, an oil storage chamber 513 which is formed so as to be recessed from the inner side surface 511 and opens toward the outer surface 22 of the nut 20 is provided.

  The tubular portion 52 is inserted into the oil injection hole 43 of the bearing ring 40 and defines an oil introduction passage 521 communicating with the oil storage chamber 513. As shown in FIG. 4, the oil injection hole 43, the oil introduction passage 521, the oil storage chamber 513, and any one oil guide hole 23 extend from the outer surface 42 of the bearing ring 40 to the inner surface 21 of the nut 20. A communicating oil injection path is formed.

  As shown in FIG. 4, the length of the oil storage chamber 513 in the circumferential direction centering on the axis L is equal to or greater than the maximum interval in the circumferential direction of the two oil guide holes 23 of each set. It is formed as.

  When the bearing ring 40 rotates relative to the nut 20, the oil flow path forming member 50 also rotates relative to the nut 20 in conjunction with the bearing ring 40, and the inner side surface 511 of the orienting portion 51 is the outer surface of the nut 20 Slide 22 Then, when the oil flow path forming member 50 rotates and comes over the opening of the oil guide hole 23 in the outer surface 22 of the nut 20, the oil storage chamber 513 and the oil guide hole 23 communicate with each other. That is, the above-described oil injection path is formed.

  In addition, in order to soften the friction when the oil flow path forming member 50 slides with respect to the nut 20, the localization portion 51 is preferably made of a material having a low coefficient of friction or a porous material. As an example, it can be made of plastic or felt having a coefficient of friction of 0.2 to 0.3.

  The circumferential bearing unit 60 is disposed between the inner surface 41 of the bearing ring 40 and the outer surface 22 of the nut 20 to allow circumferential rotation of the bearing ring 40 about the axis L relative to the nut 20. There is. The circumferential bearing unit 60 has a second ball holder 61 and a plurality of second balls 62 respectively held by the second ball holder 61. The plurality of second balls 62 are respectively fitted to the third ball rolling groove 25 of the nut 20 and the fourth ball rolling groove 45 of the bearing ring 40.

By providing the above configuration, the ball spline mechanism allows the user to apply oil or grease (hereinafter referred to as oil or the like) to the outer surface 42 of the bearing ring 40, as indicated by arrows in FIG. When injected into the exposed oil injection hole 43, the oil flows into the oil storage chamber 513 via the oil injection hole 43 and the oil introduction passage 521.

And, as described above, when the oil flow path forming member 50 comes over the opening of the oil guide hole 23 in the process of the oil flow path forming member 50 rotating with the bearing ring 40 The two oil guide holes 23 communicate with each other to form the above-mentioned oil injection path. As a result, oil or the like in the oil storage chamber 513 flows to the oil guide hole 23, reaches the linear bearing unit 30 between the spline shaft 10 and the nut 20, and the linear bearing unit 30 is lubricated. Therefore, the linear movement of the nut 20 with respect to the spline shaft 10 becomes smooth.

  Further, when the oil flow path forming member 50 is not positioned above the opening of the oil guide hole 23 in the process of the oil flow path forming member 50 rotating with the bearing ring 40, the oil storage chamber 513 is any oil guide hole 23. Since it does not communicate, ie, the above-mentioned oil injection path is interrupted, oil etc. do not flow into the oil guide hole 23. Thus, oil and the like are prevented from flowing excessively to the linear bearing unit 30.

  Thus, in the present invention, oil and the like are injected from the outside of the outer bearing ring 40 by forming the above-described oil injection path, and the inner linear bearing unit 30 is lubricated. It becomes possible. Furthermore, when the bearing ring 40 rotates, the oil storage chamber 513 of the oil flow path forming member 50 and the oil guide hole 23 of the nut 20 become communicated or disconnected by the rotation of the oil flow path forming member 50. Lubrication is prevented, and appropriate lubrication of the linear bearing unit 30 is possible.

  If the localization portion 51 of the oil flow path forming member 50 is made of a material having a low coefficient of friction or a porous material as in the present embodiment, the localization portion 51 when the oil flow path forming member 50 rotates. Abrasion between the inner surface 511 of the second embodiment and the outer surface 22 of the nut 20 can be reduced, and the above-mentioned oil injection passage is sealed.

  Further, as described above, since the two third ball rolling grooves 25 communicate with each other on the outer surface 22 of the nut 20 through the plurality of communication grooves 26, oil or the like is injected from the oil injection hole 43 After flowing into the oil storage chamber 513, when the oil flow path forming member 50 comes on any one communication groove 26 in the process of rotating with the bearing ring 40, oil etc. circulates through the communication groove 26. As it flows into both sides of the direction bearing unit 60, the plurality of second balls 62 can be lubricated.

As described above, according to the ball spline mechanism of the present invention, it is possible to lubricate the linear bearing unit 30 and the circumferential bearing unit 60 effectively with a simple structure as in the above embodiment. It becomes possible.

  As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the summary.

10 spline shaft 11 outer peripheral surface 12 first ball rolling groove 20 nut 21 inner surface 22 outer surface 23 oil guide hole 24 second ball rolling groove 25 third ball rolling groove 26 communication groove 30 linear bearing unit 31 First ball holder 32 first ball 40 bearing ring 41 inner surface 42 outer surface 43 oil injection hole 45 fourth ball rolling groove 50 oil flow path forming member 51 localization portion 511 inner side surface 512 outer side surface 513 oil storage chamber 52 tubular Part 521 Oil introduction path 60 circumferential bearing unit 61 second ball holder 62 second ball

Claims (10)

A screw shaft having a plurality of pairs of first ball rolling grooves extending in parallel to a predetermined axis formed on an outer peripheral surface;
A plurality of pairs of second ball rolling grooves, which are provided to surround the screw shaft and are opposed to the first ball rolling grooves, are formed on the inner surface, and the inner surface and the inner surface are opposite to each other. A nut formed with a plurality of oil guide holes penetrating between the outer surface of the
A linear bearing unit in which a plurality of first balls are fitted between the corresponding first ball rolling groove and the corresponding second ball rolling groove;
A bearing ring disposed to surround the nut and having an oil injection hole formed between opposite inner and outer surfaces;
It has an orientation portion disposed between the bearing ring and the nut, and an oil introduction passage corresponding to the oil injection hole, and the orientation portion opens toward the outer surface of the nut and the oil An oil flow path forming member provided with an oil storage chamber communicating with the introduction path;
The oil injection hole, the oil introduction passage, the oil storage chamber, and the oil guide hole form an oil injection path communicating the outer surface of the bearing ring to the inner surface of the nut. , Ball screw mechanism. The nut is provided with at least one third ball rolling groove formed in the outer surface so as to surround the axis.
The bearing ring is provided with at least one fourth ball rolling groove formed in the inner surface so as to surround the axis in correspondence with the third ball rolling groove;
A circumferential bearing unit disposed between the bearing ring and the nut, engaged with the third ball rolling groove and the fourth ball rolling groove, and rotating the bearing ring with respect to the nut Equipped
In the oil injection passage, the oil passage and the oil guide hole communicate with each other by the oil passage forming member rotating with the bearing ring by the circumferential bearing unit, and the oil passage The ball screw mechanism according to claim 1, wherein the forming member is switched between a second state where the forming member is not located above the opening of the oil guide hole. A screw shaft extending along a predetermined axis, the screw shaft having an outer peripheral surface and a plurality of pairs of first ball rolling grooves each formed to be recessed from the outer peripheral surface and extending parallel to the axis , Screw shaft,
A nut provided to surround the screw shaft and movable along the screw shaft, the nut having an inner surface facing the outer circumferential surface of the screw shaft and an outer surface opposite to the inner surface. Further, a plurality of oil guide holes penetrating from the outer surface to the inner surface, and a plurality of pairs of second ball rotations formed so as to be respectively recessed from the inner surface and facing the first ball rolling groove A moving groove, at least one third ball rolling groove formed to be recessed from the outer surface and extending to surround the axis, and formed to be recessed from the outer surface, and the third ball rolling A nut provided with at least one communicating groove in communication with the groove;
A linear bearing unit disposed between the outer circumferential surface of the screw shaft and the inner surface of the nut for guiding the movement of the nut along the screw shaft, the first ball holder; The first ball rolling groove and the second ball rolling groove, which have a plurality of sets of first balls respectively held by one ball holder, and the first balls of each set correspond to each other A linear bearing unit fitted with the
A bearing ring arranged to surround the nut and rotatable about the axis, the bearing ring having an inner surface facing the outer surface of the nut and an outer surface opposite to the inner surface, and the outer surface And an oil injection hole penetrating from the inner surface to the inner surface, and at least one fourth ball rolling groove recessed from the inner surface so as to surround the axis in correspondence with the third ball rolling groove. With the bearing ring provided,
The positioning portion disposed between the inner surface of the bearing ring and the outer surface of the nut, and the oil introduction passage corresponding to the oil injection hole, and the positioning portion includes the outer surface of the nut An oil flow path forming member provided with an oil storage chamber which is open toward the end and in communication with the oil introduction path;
A circumferential bearing unit disposed between the inner surface of the bearing ring and the outer surface of the nut for enabling rotation of the bearing ring relative to the nut about the axis, the second bearing unit comprising: A ball holder and a plurality of second balls respectively held by the second ball holder, wherein each of the second balls includes the third ball rolling groove and the fourth ball rotation A circumferential bearing unit fitted in the moving groove,
Forming an oil injection path communicating the outer surface of the bearing ring to the inner surface of the nut by the oil injection hole, the oil introduction passage, the oil storage chamber, and any one of the oil guide holes; Ball screw mechanism characterized by   The plurality of oil guide holes are arranged side by side in a row, and each pair of two oil guide holes are arranged in a pair, and the maximum interval in the circumferential direction around the axis of the two oil guide holes of each set is the oil reservoir The ball screw mechanism according to claim 3, wherein the length of the chamber in the circumferential direction is shorter than that of the chamber.   The nut is provided with two of the third ball rolling grooves spaced from each other in a direction parallel to the axis, and the communication groove extends between the two third ball rolling grooves. The ball screw mechanism according to claim 3, which is in communication.   The plurality of oil guide holes are arranged side by side with each other between two of the third ball rolling grooves so as to form one set, and each set is equally spaced around the axis. 6. The ball screw mechanism according to claim 5, which is arranged.   The oil flow path forming member further includes a tubular portion connected to the localization portion, the tubular portion is inserted into the oil injection hole, and the oil introduction path is defined by the tubular portion. The ball screw mechanism according to claim 3.   The localization portion of the oil flow path forming member is an outer surface formed in an arc-like convex surface so as to abut on the inner surface of the bearing ring, and an opposite surface of the outer surface and the outer surface of the nut The ball screw mechanism according to claim 3, further comprising: an inner side surface formed in an arc-shaped concave surface so as to abut on the surface, wherein the oil storage chamber is formed to be recessed from the inner side surface.   The ball screw mechanism according to claim 8, wherein the localization portion of the oil flow path forming member is made of a material having a low coefficient of friction.   The ball screw mechanism according to claim 8, wherein the localization portion of the oil flow path forming member is made of a porous material.

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