JP2013167319A - Linear motion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motion device that achieves space-saving in a longitudinal direction (in an axial direction).SOLUTION: A linear motion device 1 includes:a screw axes 10A, B where a first rolling channel 11 and a second rolling channel 12 having different winding directions are spirally provided on their outer circumferential surface; a first nut 21 that makes the screw axes move in their axial direction; a second nut 22 provided with a table 60 and relatively moving in the axial direction of the screw axes; a plurality of support members 30 for supporting the screw axes; and a plurality of motors 41, 42 coupled so as to transmit a rotational force to the first nut 21 and the second nut 22, respectively via a transmission member 50.

Description

  The present invention relates to a linear motion device using a ball screw.

Conventionally, in a linear motion device (drive device) using a ball screw, as a structure for improving the feed rate, “a structure for increasing the rotational speed of a screw shaft or a nut” or “a screw provided on a screw shaft or a nut” The structure which enlarges the lead | read | reed of a groove | channel "is mentioned.
Therefore, Patent Document 1 proposes a drive device that can obtain a necessary acceleration / deceleration effect by arranging a pair of nuts corresponding to screw shafts in which two types of screw grooves with different lead or screw winding directions are formed. Has been.

  Further, as another structure for achieving the same object, there is a structure in which two screw shafts having different screw configurations are supported by a support member as shown in FIGS. Specifically, in the linear motion device 100 shown in FIGS. 3A and 3B, a screw shaft 111 and a screw shaft 112 having different winding directions are screwed with a nut 121 and a nut 122, respectively. 130 is provided, and the nut 121 is fixed via a fixing member 140. A motor 150 is connected to one end 111 a of the screw shaft 111. Both ends 111a and 111b of the screw shaft 111 are rotatably supported by movable support members 161 and 160. Further, both ends 112a and 112b of the screw shaft 112 are rotatably supported by movable support members 162 and 160. The support member 160 rotatably supports the screw shafts 111 and 112 with the other end portion 111 b of the screw shaft 111 facing one end portion 112 a of the screw shaft 112.

  By adopting such a structure, the linear motion device 100 can shorten the support span, increase the speed at which the resonance phenomenon of the ball screw occurs, and improve the feed speed even when it is long. Further, not only the screw winding direction of the screw shafts 111 and 112 constituting the linear motion device 100 but also the leads can have different speed-up effects by having different forms.

Japanese Patent Laid-Open No. 2001-21019

However, in the configuration of the linear motion device shown in FIGS. 3A and 3B, since the screw shaft moves in the axial direction while rotating, it is necessary to take a long space in the longitudinal direction (axial direction) of the linear motion device. There was a problem that there was.
Accordingly, the present invention has been made paying attention to the above-described problems, and an object thereof is to provide a linear motion device that realizes space saving in the longitudinal direction (axial direction).

The linear motion device according to claim 1 of the present invention for solving the above-described problem is a screw shaft in which a first rolling groove and a second rolling groove having different winding directions are spirally provided on an outer peripheral surface;
A rolling element in which movement of the screw shaft in the axial direction is restricted, and a rolling groove corresponding to the first rolling groove is provided on the inner peripheral surface, and is formed by the rolling groove and the first rolling groove. A first nut that moves the screw shaft in the axial direction via a plurality of rolling elements disposed in a rolling path;
A table is provided, a rolling groove corresponding to the second rolling groove is formed on the inner peripheral surface, and a plurality of rolling grooves arranged in the rolling element rolling path formed by the rolling groove and the second rolling groove are provided. A second nut that moves relative to the axial direction of the screw shaft via the rolling elements of
A plurality of support members for supporting the screw shaft;
And a plurality of motors coupled to transmit the rotational force to each of the first nut and the second nut via the transmission member.

The linear motion device according to claim 2 of the present invention is the linear motion device according to claim 1, wherein the motor is provided so as to be arranged between the first nut and the second nut. It is said.
The linear motion device according to claim 3 of the present invention is the linear motion device according to claim 1 or 2, wherein the screw shaft is a first screw shaft in which a rolling groove is spirally formed on an outer peripheral surface. And a second screw shaft having a rolling groove spirally formed on the outer peripheral surface in a winding direction different from that of the first screw shaft.

  The linear motion device according to claim 4 of the present invention is the linear motion device according to any one of claims 1 to 3, wherein the screw shaft has a hollow hole extending substantially over its entire length. A long middle shaft is inserted concentrically with a slight gap in the radial direction in the hollow hole, and both ends of the middle shaft are held by the screw shaft by holding means, and the gap is a radius of the screw shaft. The center shaft is adapted to collide with the inner surface of the hollow hole during vibration in a direction.

  ADVANTAGE OF THE INVENTION According to this invention, the linear motion apparatus which implement | achieves space saving of a longitudinal direction (axial direction) can be provided.

It is a figure which shows the structure in 1st Embodiment of the linear motion apparatus which concerns on this invention, (a), (c) is a top view, (b) is a front view. It is a figure which shows the structure in 2nd Embodiment of the linear motion apparatus which concerns on this invention, (a) is a top view of a linear motion apparatus, (b) is a top view of a screw shaft. It is a figure which shows the structure of the conventional linear motion apparatus, (a) is a top view, (b) is a front view.

Embodiments of a linear motion device according to the present invention will be described below with reference to the drawings.
(First embodiment)
1A and 1B are diagrams showing a configuration of a linear motion device according to a first embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is a front view.
As shown in FIGS. 1A and 1B, the linear motion device 1 includes a base portion 2, a rail 3, a slider 4, a screw shaft 10, a first nut 21, and a second nut 22. A nut 20, a support member 30, a motor 40, and a transmission member 50.

<Screw shaft>
As for the screw shaft 10, the 1st rolling groove 11 and the 2nd rolling groove 12 from which a winding direction differs are provided in the outer peripheral surface spirally.
<First nut>
The first nut 21 is provided with a rolling groove (not shown) corresponding to the first rolling groove 11 on the inner peripheral surface thereof. And it moves relatively in the axial direction of the screw shaft 10 via a plurality of rolling elements (not shown) disposed in the rolling element rolling path formed by this rolling groove and the first rolling groove 11. Thus, the first nut 21 is provided for the screw shaft 10.
Here, the 1st nut 21 is being fixed to the base part 2 via the bracket 25 so that the movement about an axial direction (axial direction of the screw shaft 10) is restrict | limited. Therefore, as described above, the screw shaft 10 installed to move relative to the first nut 21 can move in the axial direction of the screw shaft 10 with respect to the first nut 21 fixed to the base portion 2. It is said.
Further, as shown in FIG. 1, a cylindrical pulley portion 21 a around which a transmission member 50 (described later) is bridged is formed at the end of the first nut 21 with a diameter smaller than that of the outer peripheral surface of the first nut 21. It may be provided concentrically with the 1 nut 21.

<Second nut>
As for the 2nd nut 22, the rolling groove corresponding to the 2nd rolling groove 12 is formed in the internal peripheral surface. And it moves relatively in the axial direction of the screw shaft 10 via a plurality of rolling elements (not shown) disposed in the rolling element rolling path formed by this rolling groove and the second rolling groove 12. Thus, the first nut 22 is provided for the screw shaft 10.
Here, the second nut 22 is provided with a table 60. The table 60 is connected to a pair of sliders 4, 4 that are movably straddled in the extending direction with respect to a pair of rails 3, 3 laid in parallel on the base portion 2. That is, a table 60 is provided on the opposite side of the second nut 22 from the base portion 2, and the table 60 is connected to the sliders 4 and 4 so that an object placed on the table 60 does not fall. The table 60 is directly connected to the sliders 4 and 4, and is synchronized with the second nut 22 that moves in the axial direction along with the rotation of the second nut 22 itself. The second nut is movable in the axial direction. 22 is indirectly connected.
Further, as shown in FIG. 1, a cylindrical pulley portion 22 a around which a transmission member 50 (described later) is bridged is formed at the end of the second nut 22 with a smaller diameter than the outer peripheral surface of the second nut 22. It may be provided concentrically with the two nuts 22.

<Supporting member>
A plurality of support members 30 are installed in the vicinity of both end portions 10 a and 10 b of the screw shaft 10 so as to support the screw shaft 10. The support member 30 is, for example, a bearing.
<Motor>
The motor 40 includes a first motor 41 attached to the first nut 21 via the transmission member 50 and a second motor 42 attached to the second nut 22 via the transmission member 50. The first motor 41 and the second motor 42 are preferably provided so as to be aligned with the screw shaft 10 between both end portions 10a and 10b of the screw shaft 10, respectively. As a specific installation form of the first motor 41 and the second motor 42, the rotation shafts 41 a and 42 a of the first motor 41 and the second motor 42 are respectively connected to the first nut 21 and the first motor via the transmission members 50 and 50. The two nuts 22 are connected to the outer peripheral surfaces of the two nuts 22 or the pulley portions 21a and 22a so as to transmit the rotational force. At this time, the first motor 41 has a direction in which the rotating shaft 41a of the first motor 41 protrudes and an outer end of the first nut 21 (an end opposite to the end facing the second nut 22). It is installed so that the direction is almost the same. Similarly, the second motor 42 has a direction in which the rotating shaft 42a of the second motor 42 protrudes and an end portion on the outer side of the second nut 22 (an end portion opposite to the end portion facing the first nut 21). It is installed so that the direction is almost the same. Further, the first motor 41 and the second motor 42 are installed such that the tip portions of the respective rotary shafts 41 a and 42 a are aligned with the outer end portions of the first nut 21 and the second nut 22.

  Here, the first motor 41 and the second motor 42 are also sliders 4, 4 laid across the pair of rails 3, 3 laid in parallel on the base portion 2 so as to be movable in the extending direction. It is connected to the. As described above, the first motor 41 and the second motor 42 are connected to the sliders 4 and 4, so that the first motor 41 and the second motor 42 can smoothly move in the axial direction of the screw shaft 10.

<Transmission member>
The transmission member 50 is a member that transmits the rotational force generated by the rotation shafts 41 a and 42 a of the first motor 41 and the second motor 42 as rotational force that rotates the first nut 21 and the second nut 22. As the transmission member 50, for example, a belt or the like spanning between the rotation shafts 41 a and 42 a and the outer peripheral surfaces of the first nut 21 and the second nut 22 or the pulley portions 21 a and 22 a is employed. In this way, the first motor 41 and the second motor 42 are connected to the first nut 21 and the second nut 22 via the transmission member 50 so as to be folded back with respect to the first nut 21 and the second nut 22. Has been.

  As a driving method of the linear motion device 1 configured as described above, the screw shaft 10 is moved by rotating the first nut 21 fixed to the base portion 2. At this time, since the screw shaft 10 relatively moves in the axial direction by the rotation of the first nut 21, it moves in the axial direction without rotating. Further, the speed of the table 60 is increased by rotating the second nut 22 screwed into the screw shaft 10 moving in the axial direction.

  As described above, in the linear motion device 1 of the present embodiment, the first motor 41 and the second motor 42 connected to the first nut 21 and the second nut 22 via the transmission member 50 are replaced with the first motor 41. The second motor 42 is provided so as to be lined up inward. Therefore, since the motor 40 is not provided on the extension of the screw shaft 10 in the axial direction, space saving in the longitudinal direction (axial direction) can be realized. Further, by providing the first motor 41 and the second motor 42 so as to be arranged between the first nut 21 and the second nut 22, further space saving in the longitudinal direction (axial direction) can be realized.

  Here, in the present embodiment, the first rolling groove 11 and the second rolling groove 12 having different winding directions are provided on the outer peripheral surface of the screw shaft 10 in a spiral shape. The screw shafts may be connected by a shaft coupling (shaft coupling) or the like. Specifically, as shown in FIG. 1C, the first screw shaft 10A in which the rolling groove 11 is formed in a spiral shape on the outer peripheral surface, and the outer peripheral surface in a winding direction different from the first screw shaft 10A. It is good also as the screw shaft 10 formed by connecting with the shaft coupling (shaft coupling) 13 etc. the 2nd screw shaft 10B in which the rolling groove 12 was formed helically. By setting it as such a structure, the yield in the manufacturing process of the screw shaft 10 can be improved.

  When the screw shaft 10 is formed by connecting the first screw shaft 10A and the second screw shaft 10B having different forms as described above, the end of the first screw shaft 10A and the end of the second screw shaft 10B It is preferable that a support member for connecting the first screw shaft 10A and the second screw shaft 10B is further provided. By doing in this way, the space | interval which supports the screw shaft 10 by a support member becomes short, and the intensity | strength in the connection part of the screw shaft 10 can be improved more.

(Second Embodiment)
FIGS. 2A and 2B are diagrams showing the configuration of the linear motion device according to the second embodiment of the present invention, wherein FIG. 2A is a plan view of the linear motion device, and FIG. 2B is a plan view of the screw shaft. The present embodiment is different from the first embodiment described above only in the configuration of the screw shaft. Therefore, the description of the same configuration as that of the first embodiment described above will be omitted, and the difference will be described. Will be described. In FIG. 2, the base portion 2, the rail 3, and the slider 4 are omitted.

  As shown in FIG. 2A, in the linear motion device 1 of the present embodiment, the screw shaft 10 has a hollow hole 14 that extends over almost the entire length, and a slight gap in the radial direction is formed in the hollow hole 14. The long middle shaft 15 is inserted concentrically. And both ends of the middle shaft 15 are held by the screw shaft 10 by holding means. Further, the gap is formed so that the middle shaft 15 collides with the inner surface of the hollow hole 14 when the screw shaft 10 vibrates in the radial direction.

  Specifically, as shown in FIG. 2 (b), the screw shaft 10 used in the linear motion device 1 of the present embodiment has a hollow hole 14 that extends over almost the entire length. The middle shaft 15 is arranged with a slight gap in the radial direction. Small diameter portions are formed at both ends of the intermediate shaft 15, and male screw grooves 15 a for holding the intermediate shaft 15 are provided in the small diameter portion.

  The middle shaft fixing member 16 that is a holding means is a stepped member and has a fitting portion that fits into the hollow hole 14 of the screw shaft 10 at one end. A female thread groove 16 a that is screwed into the male thread groove 15 a of the middle shaft 15 is provided on the shaft end surface on the fitting portion side of the middle shaft fixing member 16. The outer diameter portion on the screw groove side of the middle shaft fixing member 16 is fitted with the inner diameter portion of the hollow hole 14 of one screw shaft, and is fixed by a bolt 17. The female screw groove 16 a of the middle shaft fixing member 16 is screwed with one male screw groove 15 a of the middle shaft 15 inserted through the hollow hole 14 of the screw shaft 10. The female screw groove 16a of the middle shaft fixing member 16 is screwed into the other male screw groove 15a of the middle shaft 15, and the fitting portion of the middle shaft fixing member 16 is fitted to the inner diameter portion of the hollow hole 14 of the other screw shaft 10. The bolt 17 is fixed so that the axial direction of the screw shaft 10 cannot be moved and cannot be rotated. At this time, the screwing between the male screw grooves 15a, 15a at both ends of the middle shaft 15 and the female screw grooves 16a, 16a of the middle shaft fixing members 16, 16 is tightened with an appropriate tightening force applied to the middle shaft 15, and the bolt 17 The middle shaft fixing members 16, 16 are fixed to the screw shaft 10. A small-diameter drill hole in the axial direction and a small-diameter drill hole communicating from the bottom of the drill hole to the outer surface of the central-axis fixing member are provided at the bottoms of the screw holes of the middle shaft fixing members 16 and 16. When the middle shaft fixing members 16 and 16 are screwed into the middle shaft 15 by the drill holes and the middle shaft fixing members 16 and 16 are fitted into the hollow hole 14 of the screw shaft 10, the air in the hollow hole 14 is compressed and fitted. An air vent hole 16b is provided to allow the threaded portion of the central shaft fixing members 16, 16 to communicate with the outside so as not to be difficult to fit together. Further, the air vent hole 16b prevents the internal pressure in the hollow hole 14 from rising due to the temperature rise due to the high speed operation of the driving device 1 of the present embodiment.

  In the linear motion device 1 of the present embodiment configured as described above, when the screw shaft 10 receives vibration when the first nut 21 and the second nut 22 are rotationally driven, the screw shaft 10 is perpendicular to the axis. The middle shaft 15 tends to move in the same direction as the displacement of the screw shaft 10, but the vibration cycle of the screw shaft 10 and the vibration cycle of the middle shaft 15 are generally different, and the gap between the hollow hole 14 and the middle shaft 15 is Since it is slight, the middle shaft 15 collides with the screw shaft 10 and the vibration of the screw shaft 10 is prevented. In particular, the linear motion device according to the present embodiment is a mode in which a nut rotates, the screw shaft 10 does not rotate, and both ends of the screw shaft 10 are fixed. This is advantageous in terms of generating vibration of the screw shaft 10.

  As described above, according to the linear motion device 1 of the present embodiment, when the ball screw operates by a simple structure in which the hollow shaft 14 is provided in the screw shaft 10 and the middle shaft 15 is loosely fitted in the hollow hole 14. Vibration can be reduced. As a result, a linear motion device that can be used at a speed exceeding the critical speed can be realized, productivity can be improved, and a longer stroke of the table can be easily achieved. Further, even when speeding up is necessary, the shaft diameter of the screw shaft can be made smaller than that of the conventional screw shaft, and a cost merit that can reduce the cost of the linear motion device is also obtained.

As described above, the linear motion device 1 according to this embodiment includes the first motor 41 and the second motor 42 that are connected to the first nut 21 and the second nut 22 via the transmission member 50. The second motor 42 is provided so as to be lined up inward. Therefore, since the motor 40 is not provided on the extension of the screw shaft 10 in the axial direction, space saving in the longitudinal direction (axial direction) can be realized.
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, the linear motion device of the present embodiment is not limited to the above-described ball screw device, and linear motion devices such as ball splines and linear guides, and rolling elements such as balls and rollers are interposed between a screw shaft and a nut. It can also be applied to linear motion devices other than those described above.

DESCRIPTION OF SYMBOLS 1 Linear motion apparatus 2 Base part 3 Rail 4 Slider 10 Screw shaft 11 1st rolling groove 12 2nd rolling groove 14 Hollow hole 15 Center shaft 16 Center shaft fixing member 20 Nut 21 First nut 22 Second nut 30 Support member 40 Motor 41 1st motor 42 2nd motor 50 Transmission member 60 Table

Claims (4)

A screw shaft in which a first rolling groove and a second rolling groove having different winding directions are spirally provided on the outer peripheral surface;
A rolling element in which movement of the screw shaft in the axial direction is restricted, and a rolling groove corresponding to the first rolling groove is provided on the inner peripheral surface, and is formed by the rolling groove and the first rolling groove. A first nut that moves the screw shaft in the axial direction via a plurality of rolling elements disposed in a rolling path;
A table is provided, a rolling groove corresponding to the second rolling groove is formed on the inner peripheral surface, and a plurality of rolling grooves arranged in the rolling element rolling path formed by the rolling groove and the second rolling groove are provided. A second nut that moves relative to the axial direction of the screw shaft via the rolling elements of
A plurality of support members for supporting the screw shaft;
A linear motion device comprising: a plurality of motors coupled to transmit a rotational force to each of the first nut and the second nut via a transmission member.   The linear motion device according to claim 1, wherein the motor is provided so as to be arranged between the first nut and the second nut.   The screw shaft includes a first screw shaft in which a rolling groove is spirally formed on the outer peripheral surface, and a second screw shaft in which the rolling groove is spirally formed on the outer peripheral surface in a winding direction different from that of the first screw shaft. The linear motion device according to claim 1, wherein the linear motion device is connected to each other.   The screw shaft has a hollow hole extending over almost the entire length, and a long middle shaft is inserted concentrically with a small gap in the radial direction in the hollow hole of the screw shaft, and the middle shaft has both end portions thereof. The holding shaft is held by the screw shaft, and the gap is adapted to collide with the inner surface of the hollow hole when the screw shaft is vibrated in the radial direction. The linear motion device according to the above.

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