JP2012097807A - Ball screw nut removing and returning jig, and nut removing and returning method using jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent misalignment between the helical groove of a screw shaft and that of a nut from occurring when the nut is returned from a temporary shaft to the screw shaft, in a method for removing and returning the nut of a ball screw.SOLUTION: A jig used consists of: a guide member 1; a clamp 2; a plate member 31 for joining them; a nut 32; and bolt 33. The guide member 1 has a protrusion 12 arranged in the helical groove 41 of the screw shaft 4, and formed at the front end of its male screw part 11. The clamp 2 retains the outer periphery of the nut 5. One end of the plate member 31 is fixed to the clamp 2 with the bolt 33, the male screw part 11 is threaded in a female screw 31 of the other end, and the nut 32 is threaded in the male screw part 11. The protrusion 12 advances and retreats in the radial direction of the screw shaft 4 by the rotation of the male screw part 11. The screw shaft 4 is rotated relatively to the nut 5, and thereby after the nut is made into a (b) condition from an (a) condition, the nut is returned to the (a) condition. In that case, the helical groove 41 of the screw shaft 4 is guided by the protrusion 12.

Description

  The present invention relates to a jig used in a nut attaching / detaching method including a step of transferring a nut of a ball screw from a screw shaft to a temporary shaft and a step of returning the nut from the temporary shaft to the screw shaft.

The ball screw has a nut formed with a spiral groove on the inner peripheral surface, a screw shaft formed with a spiral groove on the outer peripheral surface, and a raceway (rolling path) formed by the spiral groove of the nut and the spiral groove of the screw shaft. And a ball return path that returns the ball from the end point of the track to the start point, and the nut moves relative to the screw shaft by rolling the ball in the track. .
Seals are attached to both ends of the ball screw nut in the axial direction to close the gap with the screw shaft. Further, when the circulation tube is used as the ball return path, the leg of the circulation tube is inserted into the hole provided in the nut, and the tongue formed at the tip of the leg is disposed in the spiral groove of the screw shaft. .

  Conventionally, for maintenance such as grease supply, a nut of a ball screw is transferred from a screw shaft to a temporary shaft while maintaining the assembled state of the ball disposed inside. Specifically, the nut and the ball are moved from the screw shaft to the temporary shaft by connecting the temporary shaft to the end of the screw shaft and rotating the screw shaft relative to the nut. After the maintenance is completed, the nut and the ball are returned from the temporary shaft to the screw shaft by rotating the screw shaft in the opposite direction.

  As a conventional example of such a ball screw nut attaching / detaching method, for example, there is a method described in Patent Document 1 below. In the method of Patent Document 1, in order to accurately align the screw shaft and the temporary shaft, the temporary shaft is formed at a shaft portion substantially equal to the valley diameter of the spiral groove of the screw shaft and at one end of the shaft portion. And a centering protrusion that fits into a center hole provided at an axial end of the screw shaft.

Japanese Utility Model Publication 4-17030

In the above-described ball screw nut attaching / detaching method, when the nut is returned from the temporary shaft to the screw shaft, if the spiral groove of the screw shaft and the spiral groove of the nut are misaligned, the lip portion of the contact seal or the tongue portion of the circulation tube May interfere with the screw shaft and cause damage. Japanese Patent Application Laid-Open No. H10-228707 does not describe prevention of the shift of the spiral groove.
An object of the present invention is to provide a nut attaching method including a step of moving a nut of a ball screw from a screw shaft to a temporary shaft and a step of returning from the temporary shaft to the screw shaft. This is to prevent a shift between the spiral groove of the nut and the spiral groove of the nut.

  In order to solve the above-mentioned problems, the present invention fixes a temporary shaft to one end of a screw shaft of a ball screw, and rotates the screw shaft relative to the nut to arrange the nut inside. The nut is placed inside by removing the nut and moving the screw shaft from the screw shaft to the temporary shaft while rotating the ball shaft relative to the nut. And a nut return step for holding the assembled state of the ball and returning it from the temporary shaft to the screw shaft, and a jig for use in a nut mounting method of the ball screw, which is disposed in the spiral groove of the screw shaft, A ball screw nut attaching / detaching jig is provided that includes a guide portion that guides a spiral groove of a screw shaft during relative rotation with respect to the nut, and a fixing portion with respect to the nut.

  As a ball screw nut attaching / detaching method using the jig of the present invention, the jig is fixed to the nut by the fixing portion in a state where the guide portion is disposed in the spiral groove of the screw shaft. After setting the relationship between the helical groove of the screw shaft and the helical groove of the nut before removing, the nut removing step while guiding the helical groove of the screw shaft with the guide portion, without removing the jig, There is a method of performing the nut returning step while guiding the spiral groove of the screw shaft with the guide portion.

According to this method, in the nut removing step and the nut returning step, the screw shaft moves relative to the nut in the axial direction while the spiral groove is guided by the guide portion of the jig. The relationship between the spiral groove of the screw shaft before the nut is removed and the spiral groove of the nut is maintained. Therefore, according to the nut attaching / detaching jig of the present invention, when the nut is returned from the temporary shaft to the screw shaft by the nut attaching / detaching method, no deviation occurs between the spiral groove of the screw shaft and the spiral groove of the nut. Can be.
As an example of the nut attaching / detaching jig according to the present invention, the fixing portion includes a clamp that holds an outer peripheral portion of the nut. And a coupling member coupled along the axial direction of the shaft. According to this jig, the jig can be easily attached to and detached from the ball screw.

  By using the jig of the present invention, by performing a nut removing method that includes a nut removing step of moving the nut of the ball screw from the screw shaft to the temporary shaft, and a nut returning step of returning the nut from the temporary shaft to the screw shaft, It is possible to prevent a shift between the spiral groove of the screw shaft and the spiral groove of the nut in the nut returning process.

It is a figure explaining the nut attaching / detaching jig | tool equivalent to embodiment of this invention, Comprising: It is a front view which shows the state with which the nut attaching / detaching jig was attached to the ball screw. It is a figure explaining the jig | tool for nut attachment / detachment equivalent to embodiment of this invention, Comprising: It is AA sectional drawing of FIG. It is a figure explaining the nut attachment / detachment method using the nut attachment / detachment jig | tool equivalent to embodiment of this invention. It is a figure explaining the nut attaching / detaching jig partially different from FIGS. 1 and 2, and is a front view showing a state in which the nut attaching / detaching jig is attached to the ball screw. FIG. 5 is a view for explaining a nut attaching / detaching jig that is partially different in shape from FIGS. 1 and 2, and is a view taken in the direction of arrow B in FIG. It is a top view which shows another embodiment of the jig | tool for nut attachment / detachment of this invention. It is a partially broken front view which shows the state in which the jig | tool for nut attachment / detachment of FIG. 6 was attached to the nut of the ball screw.

Embodiments of the present invention will be described below.
As shown in FIGS. 1 and 2, the ball screw nut attaching / detaching jig of this embodiment includes a guide member 1 and a clamp 2, and a plate-like member 31, a nut 32, and a bolt 33 for connecting them. It is configured.
The guide member 1 includes a male screw portion 11 in which a male screw is formed on a round bar material having a predetermined length, and a protrusion 12 formed in a shaft shape having a diameter smaller than the valley diameter of the male screw portion 11 at the tip thereof. A hexagonal hole 13 is formed in the base end portion of 11. The tip of the protrusion 12 is formed into a spherical surface. The protrusion 12 has a dimension that fits into the spiral groove 41 of the screw shaft 4 of the ball screw with a slight gap.

  The clamp 2 includes a pair of holding members 21 that hold the outer peripheral portion of the nut 5 of the ball screw from both sides obtained by dividing the cross-sectional circle of the nut 5 into two parts, and a bolt 22 and a nut 23 that couple the holding members 21 together. . The holding member 21 includes a pair of inclined portions 21a that are brought into contact with the outer peripheral surface of the nut 5, a horizontal connecting portion 21b that horizontally connects both the inclined portions 21a, and a horizontal end portion 21c that extends horizontally to the outside of each inclined portion 21a. Are integrally formed.

  The inclined portion 21 a and the horizontal connecting portion 21 b of the holding member 21 are formed with an edge portion 21 d at one end along the axial direction of the nut 5 so as to be in contact with one axial end surface of the nut 5. A female screw hole 21 e that penetrates in the radial direction of the nut 5 is formed at the center of the horizontal connecting portion 21 b of the holding member 21. A through hole 21 f into which the shaft portion of the bolt 22 is inserted is formed in the horizontal end portion 21 c of the holding member 21.

The plate-like member 31 has a female screw hole 31 a corresponding to the male screw portion 11 of the guide member 1 and a through hole 31 b corresponding to the female screw hole 21 e formed in the holding member 21 of the clamp 2. One end of the plate-like member 31 is fixed to the outside of the horizontal connecting portion 21 b of one holding member 21 with a bolt 33. That is, the shaft portion of the bolt 33 passes through the through hole 31b of the plate-like member 31, and the tip thereof is screwed into the female screw hole 21e.
The male screw portion 11 of the guide member 1 is screwed into the female screw hole 31a at the other end of the plate member 31, and the nut 32 is screwed to the base end side thereof. Thereby, the guide member 1 is attached to the other end of the plate-like member 31 so that the position in the radial direction of the screw shaft 4 can be adjusted.

  The axial end 42 of the screw shaft 4 is formed in a cylindrical shape having a smaller diameter than the valley diameter of the spiral groove 41. Further, contact seals 53 are attached to the inside of both ends of the nut 5 in the axial direction, but in FIG. Are not shown by broken lines. The ball screw has a circulation tube 54 as a ball return path.

Next, a nut screw attaching / detaching method using the nut attaching / detaching jig of this embodiment will be described.
First, as shown in FIG. 3A, an axial direction of the screw shaft 4 is formed on one end of a temporary shaft 6 which is a long cylindrical body and has an outer diameter slightly smaller than the valley diameter of the spiral groove of the screw shaft 4. Insert the end 42. A disc-like stopper 7 for preventing the nut from falling off is attached to the other end of the temporary shaft 6. The outer diameter of the disk-like stopper 7 is larger than the outer diameter of the seal 53 attached to the nut 5.

  Next, the outer peripheral portion of the end portion of the nut 5 opposite to the flange 52 of the cylindrical portion 51 is held by the clamp 2. At that time, the protrusion 12 of the guide member 1 is arranged above the spiral groove 41 of the screw shaft 4. Next, the projection 12 of the guide member 1 is inserted into the spiral groove 41 of the screw shaft 4 by fitting a hexagon wrench into the hexagon hole 13 and rotating the male screw portion 11. Thereby, the relationship between the spiral groove 41 of the screw shaft 4 and the spiral groove of the nut 5 is set.

Next, a nut removing process is performed. That is, the screw shaft 4 is rotated with the nut 5 fixed. As a result, the screw shaft 4 moves relative to the nut 5 in the axial direction while the spiral groove 41 is guided by the protrusion 12 of the guide member 1, and the nut 5 moves from the screw shaft 4 together with the ball disposed inside. It moves off and moves to the temporary shaft 6. FIG. 3B shows this state.
Next, after performing the maintenance work in the state of FIG. 3B, a nut returning step is performed. That is, with the nut 5 fixed, the screw shaft 4 rotates to the opposite side to the nut removal step. As a result, the screw shaft 4 moves relative to the nut 5 in the axial direction while the spiral groove 41 is guided by the protrusion 12 of the guide member 1, and the nut 5 moves to the screw shaft 4 together with the ball disposed inside. Returning to the state shown in FIG.

Thus, in the nut removing process and the nut returning process, the screw shaft 4 moves relative to the nut 5 in the axial direction while the spiral groove 41 is guided by the protrusion 12 of the guide member 1. Later, the relationship between the spiral groove 41 of the screw shaft 4 and the spiral groove of the nut 5 before the nut 5 is removed is maintained.
Accordingly, when the nut is returned from the temporary shaft to the screw shaft by the nut attaching / detaching method, it is possible to prevent a deviation from occurring between the spiral groove of the screw shaft and the spiral groove of the nut.

In this method, the clamp 2 holds the outer peripheral portion of the nut 5 at the end opposite to the flange 52 of the cylindrical portion 51 of the nut 5, but a long bolt corresponding to the diameter of the flange 52. If 22 is used, the outer peripheral part of the flange 52 can also be held using this clamp 2. In that case, the guide member 1 is arranged on the left side of the clamp 2 in FIG.
That is, the clamp 2 constituting the nut attaching / detaching jig of this embodiment can be used for the nut 5 having a plurality of diameters by changing the length of the bolt 22. Further, by making the through hole 31b of the plate-like member 31 an elongated hole extending in the axial direction, the mounting position of the guide member 1 in the axial direction can be adjusted after the nut 2 is held by the clamp 2.

  In the nut attaching / detaching jig of this embodiment, the protrusion 12 of the guide member 1 corresponds to a guide portion of the nut attaching / detaching jig of the present invention. Further, the male screw portion 11 of the guide member 1, the nut 32, and the female screw hole 31a of the plate-like member 31 correspond to the advance / retreat member of the nut attaching / detaching jig of the present invention. Further, the plate-shaped member 31, the nut 32, and the bolt 33 correspond to the coupling member of the nut attaching / detaching jig of the present invention.

The protrusion 12 of the guide member 1 in FIGS. 1 and 2 has a spherical tip, but can be inserted into the spiral groove of the screw shaft to guide the spiral groove of the screw shaft when rotating relative to the nut of the screw shaft. If so, the shape may be a columnar shape, a quadrangular prism shape, or the like. In addition, examples of the material of the protrusion 12 include steel, plastic, and hard rubber. However, it is desirable to use plastic or hard rubber so that the spiral groove 41 of the screw shaft 4 is not damaged.
In addition, instead of the protrusion 12, a fitting portion 14 having an arc surface 14a that fits into the spiral groove 41 of the screw shaft 4 with a slight gap is formed at the tip of the male screw portion 11 as shown in FIGS. Alternatively, the guide member 10 may be used.

Furthermore, as shown in FIG. 6, the disk-shaped member 8 having the center hole 81 and the mounting hole 82 is also an embodiment of the nut attaching / detaching jig of the present invention. The center hole 81 of the disk-shaped member 8 corresponds to a guide part, and the attachment hole 82 corresponds to a fixed part.
As shown in FIG. 7, the disk-shaped member 8 is fixed to the bottom surface of the recess 55 provided at one end in the axial direction of the nut 5 through the mounting hole 82 with the screw shaft 4 passing through the center hole 81 with the bolt 9. The The center hole 81 has a shape capable of guiding the spiral groove 41 in the nut removing process and the nut returning process described above according to the cross-sectional shape of the screw shaft 4.

DESCRIPTION OF SYMBOLS 1 Guide member 10 Guide member 11 Male thread part (advance / retreat member)
12 Protrusion (guide part)
13 Hexagonal hole 14 Fitting part (guide part)
14a Arc surface 2 Clamp (fixed part)
21 Holding member 21a Inclined portion 21b Horizontal connecting portion 21c Horizontal end portion 21d Edge portion 21e Female screw hole 21f Through hole 22 Bolt 23 Nut 31 Plate member (joining member)
31a Female screw hole 31b Through hole 32 Nut (coupling member)
33 Bolt (joining member)
4 Ball Screw Screw Shaft 41 Screw Shaft Helical Groove 42 Axial End of Screw Shaft 5 Ball Screw Nut 53 Contact Seal 54 Circulation Tube 55 Recess 6 Temporary Shaft 7 Disc Stopper 81 Center Hole (Guide)
82 Mounting hole (fixed part)
8 Disc-shaped member 9 Bolt

Claims (3)

A temporary shaft is fixed to one end of the screw shaft of the ball screw, and the screw shaft is rotated relative to the nut so that the nut is temporarily mounted from the screw shaft while maintaining the assembled state of the ball disposed inside. Removing the nut to the shaft,
A nut return step of rotating the screw shaft relative to the nut to the opposite side of the nut removing step to return the nut to the screw shaft from the temporary shaft while maintaining the assembled state of the ball disposed inside; ,
A jig used in a nut screw attaching / detaching method having
A ball screw nut attaching and detaching feature characterized by having a guide portion that is disposed in the spiral groove of the screw shaft and guides the spiral groove of the screw shaft when the screw shaft rotates relative to the nut, and a fixing portion for the nut. Ingredients. The fixed portion is composed of a clamp that holds the outer peripheral portion of the nut,
The ball screw nut attaching / detaching jig according to claim 1, further comprising: an advance / retreat member that advances and retracts the guide portion in the radial direction of the screw shaft; and a coupling member that couples the advance / retreat member and the clamp along the axial direction of the screw shaft. . A temporary shaft is fixed to one end of the screw shaft of the ball screw, and the screw shaft is rotated relative to the nut so that the nut is temporarily mounted from the screw shaft while maintaining the assembled state of the ball disposed inside. Removing the nut to the shaft,
A nut return step of rotating the screw shaft relative to the nut to the opposite side of the nut removing step to return the nut to the screw shaft from the temporary shaft while maintaining the assembled state of the ball disposed inside; ,
A ball screw nut attaching / detaching method comprising:
Using the jig according to claim 1 or 2,
In the state where the guide portion is disposed in the spiral groove of the screw shaft, the jig is fixed to the nut by the fixing portion, whereby the relationship between the spiral groove of the screw shaft and the spiral groove of the nut before the nut is removed. After setting
The nut removing step is performed while guiding the spiral groove of the screw shaft with the guide portion,
A nut screw attaching / detaching method characterized by performing the nut returning step while guiding the spiral groove of the screw shaft with the guide portion without removing the jig.

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