JP4042511B2 - Ball screw device assembly method and assembly device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembling method and an assembling apparatus for a ball screw device used for a feeding mechanism of various devices.
[0002]
[Prior art]
In the ball screw device, a screw shaft having a spiral thread groove on the outer peripheral surface and extending in the axial direction is loosely fitted with a nut having a spiral thread groove corresponding to the screw groove of the screw shaft on the inner peripheral surface. The screw groove of the nut and the screw groove of the screw shaft are opposed to each other to form a spiral load passage therebetween. A large number of balls as rolling elements are slidably loaded in the load passage, and a circulating part such as a circulation tube for infinite circulation of the balls rolling in the load passage is assembled to the nut. It has been. Then, the rotation of the screw shaft (or nut) causes the nut (or screw shaft) to move in the axial direction through the rolling of the ball.
[0003]
By the way, as a method of assembling such a ball screw device, for example, a predetermined number of balls are inserted into a nut from a ball insertion hole formed in the nut in a state in which the nut is loosely fitted to a screw shaft in which an axis is horizontally arranged. It is known that a ball is introduced into a load passage formed between a nut and a screw shaft, and then the ball insertion hole is closed by a circulation part such as a circulation tube holding a predetermined number of balls (for example, a patent) Reference 1 and Patent Document 2).
[0004]
However, in this method, the work of closing the ball insertion hole with a circulating part holding a predetermined number of balls is performed manually, so that the predetermined number of balls may not be incorporated into the nut due to the jumping out of the balls from the circulating part. There is a problem in terms of work efficiency.
Therefore, as a method for solving such a problem, for example, the following method of assembling a ball screw device has been proposed (see, for example, Patent Document 3).
[0005]
In this method, a nut with a circulating part assembled in advance is loosely fitted to a temporary shaft whose axis is arranged vertically, and the phase of the ball outlet of the ball introduction path drilled in the temporary shaft is the highest in the thread groove of the nut. After a predetermined number of balls are passed through the ball introduction path at the same time, the balls are introduced between the thread groove of the nut and the temporary shaft, and then the ball in the ball introduction path that has not been fully inserted is pushed into the ball. Then, the nut is pushed between the thread groove of the nut and the temporary shaft, and after the completion of the ball insertion, the temporary shaft and the screw shaft are engaged, and the nut and the screw shaft are fitted simultaneously with the removal of the temporary shaft.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 62-22737 [Patent Document 2]
Japanese Utility Model Publication No. 6-50108 [Patent Document 3]
Japanese Patent No. 2530401 [0007]
[Problems to be solved by the invention]
However, in the method of assembling the ball screw device described in Patent Document 3, since the ball in the ball introduction path that could not fit between the thread groove of the nut and the temporary shaft is pushed by the ball push rod, The smaller the thread groove of the nut, the more likely that the ball will be clogged, making it difficult to smoothly introduce the ball into the nut.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in order to eliminate such inconveniences, and an object thereof is to provide a ball screw device assembling method and an assembling device capable of smoothly incorporating a predetermined number of balls into a nut.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the ball screw device assembly method according to claim 1 is a ball in which a circulating part is pre-assembled on a temporary shaft having a tapered step portion between a small diameter shaft portion and a large diameter shaft portion. The nut of the screw device is loosely fitted, and in this state, a predetermined number of balls inserted from the ball passage of the ball insertion jig by inserting a ball insertion jig from the small diameter shaft portion side between the temporary shaft and the nut. The ball is introduced between the screw groove of the nut and the temporary shaft via a guide portion formed between the ball insertion jig and the tapered step portion by rotating the temporary shaft, The temporary shaft is moved relative to the nut and the ball insertion jig toward the small-diameter shaft portion, and the ball positioned on the guide portion is moved over the taper step portion to form a thread groove of the nut. Between the temporary shaft and the Characterized by fitting a screw shaft of a ball screw device and.
[0010]
The method of assembling the ball screw device according to claim 2 is the method according to claim 1, wherein the nut is eccentric with respect to the temporary shaft when the ball is introduced between the screw groove of the nut and the temporary shaft. It is characterized by that.
Assembling apparatus of the ball screw device according to claim 3, the nut of the ball screw device previously circulating member was only assembling has a tapered step portion between the small-diameter shaft portion and the large diameter shaft portion is loosely fitted A temporary shaft, a driving means for rotating the temporary shaft, a ball passage that is fitted from the small-diameter shaft portion side between the temporary shaft and the nut and into which a predetermined number of balls are inserted, and the ball A ball insertion jig having a guide surface for forming a guide portion between the taper step portion and a guide portion for introducing a ball coming out of the passage between the screw groove of the nut and the temporary shaft; A moving means for moving the nut and the ball insertion jig relative to the small diameter shaft portion is provided.
[0011]
A ball screw device assembling apparatus according to claim 4 is the ball stopper according to claim 3, wherein the ball that has come out of the ball passage is prevented from interfering with the ball introduced into the thread groove of the nut prior to the ball. the provided to partition between the ball insertion jig of the ball outlet portion and the guide portion of the circulating member to the ball outlet of the passage Rutotomoni, the ball coming from the ball passage and the tapered stepped portion A protrusion for guiding the guide portion between the guide surface and the guide surface is provided at the tip of the ball stopper .
The invention according to claim 5 is characterized in that, in claim 3 or 4, an elastic body is applied, embedded, shrink-fitted or adhered to the outer peripheral surface of the temporary shaft having the tapered step portion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view for explaining a ball screw device assembling apparatus as an example of an embodiment of the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 (a) is for explaining a ball insertion jig. FIG. 3 (b) is a view as seen from the right side of FIG. 3 (a), FIG. 3 (c) is a view as seen from the upper side of FIG. 3 (a), and FIG. FIG. 5 is a descriptive cross-sectional view of the nut and the ball insertion jig as viewed from the side, and FIG. 5A is an explanatory view of the nut and the ball insertion jig as viewed from above. FIG. 5B is a cross-sectional view taken along the line AA of FIG. 5A, and FIG. 6A is an explanatory view for explaining the operation of the assembly device of the ball screw device. FIG. 6B is a sectional view taken along the line BB in FIG. 6A, and FIG. 7 is a diagram for explaining the floating mechanism. Figure 8 is a diagram for explaining another embodiment of the present invention.
[0013]
As shown in FIGS. 1 and 2, the ball screw device assembling apparatus includes a temporary shaft 3 on which a nut 1 of a ball screw device in which a circulation tube (circulation part) 25 is assembled in advance is loosely fitted, and a nut 1. A floating mechanism 70 that clamps and holds, a temporary shaft support portion 9 that rotatably supports the left end side of the temporary shaft 3, and a ball fitted between the temporary shaft 3 and the nut 1 from the left end side of the nut 1. An insertion jig 4, a ball distribution supply feeder (not shown) for cutting out a predetermined number of balls from the ball storage portion and supplying the balls to the ball insertion jig 4 via the ball chute 10, and the right end of the temporary shaft 3 The screw shaft right end support portion 8 that rotatably supports the right end portion of the screw shaft 2 of the ball screw device engaged on the side, and the left end portion of the temporary shaft 3 are coupled via the coupling 34 to the temporary shaft 3 and the screw. Driving mode that applies rotational force to the shaft 2 Data and a (driving means) 11.
[0014]
The temporary shaft support portion 9, the floating mechanism 70, and the screw shaft right end support portion 8 are attached to the slider 32 of the linear guide device, and are supported so as to be movable and positioned in the axial direction. Of course, a dovetail groove or a V clamp may be used instead of the linear guide device.
In addition, a transparent member (not shown) such as an acrylic plate is used on one side of the ball chute 10 so that a predetermined number of balls are supplied by distributing and cutting out the balls, You can check if there is a problem.
[0015]
As shown in FIG. 4, the temporary shaft 3 has a small-diameter shaft portion 3a on the left end side and a large-diameter shaft portion 3b on the right end side, and has a tapered step portion 21 between both shafts. The large-diameter shaft portion 3b has a cylindrical shape, and the screw shaft 2 is inserted from the right end side opening. The screw shaft 2 is center-supported by a temporary shaft center support member 7 provided in the large-diameter shaft portion 3b. Has been. The large-diameter shaft portion 3b has a diameter capable of holding the ball on the BCD (ball center diameter) of the thread groove 22 of the nut 1.
[0016]
As shown in FIGS. 3 and 4, the ball insertion jig 4 has a cylindrical shape and is fitted between the temporary shaft 3 and the nut 1 from the small diameter shaft portion 3 a side of the temporary shaft 3. A ball passage 26 penetrating in the axial direction is formed in the ball insertion jig 4, and a predetermined number of balls are inserted into the ball passage 26 from the ball chute 10.
Then, by rotating the temporary shaft 3 and the screw shaft 2 by the drive motor 11 (clockwise direction when viewed from the left end side: see FIG. 6B), the ball inserted into the ball passage 26 is moved to the ball insertion jig 4. It is introduced between the thread groove 22 of the nut 1 and the temporary shaft 3 and into the circulation tube 25 through a guide portion 20 a formed between the guide surface 20 of the temporary shaft 3 and the tapered step portion 21 of the temporary shaft 3.
[0017]
Here, the ball outlet portion 23 of the ball passage 26 is positioned on the upper side in the circumferential direction of the screw groove 22 so that the ball can easily flow through the guide portion 20a to the screw groove 22 of the nut 1 by its own weight.
The guide surface 20 of the ball insertion jig 4 is inclined so as to guide the ball to the screw groove 22 of the nut 1, so that the ball inserted into the ball passage 26 has its own weight along the guide surface 20. It is regulated by the taper step portion 21 of the temporary shaft 3 while dropping and flows into the thread groove 22 of the nut 1.
[0018]
As shown in FIGS. 3 and 5, the ball outlet portion 23 of the ball insertion jig 4 is provided with a ball stopper 27 that partitions the outlet side of the circulation tube 25 and the guide portion 20a. 27 stops the preceding ball during the ball introduction operation at the outlet portion of the circulation tube 25, thereby preventing interference between the ball introduced from the ball outlet portion 23 into the screw groove 22 and the preceding ball.
[0019]
A protrusion 28 is provided at the tip of the ball stopper 27. The protrusion 28 has a function of changing the traveling direction of the ball flowing from the ball passage 26 and guiding the ball along the guide portion 20a while preventing the ball from directly contacting the groove shoulder of the screw groove 22 of the nut 1. ing. Of course, the ball contact portion of the protrusion 28 may be a curved surface having a cylindrical shape.
[0020]
As an example for easily introducing the ball, an air jet (not shown) is attached to the tip of the ball stopper 27 so that the ball is pushed out from the ball outlet 23 and then the ball is guided to the guide 20 by air. It is also possible to facilitate the flow into the screw groove 22 along the line.
Further, a ball damper pin (not shown) may be provided in the middle of the ball chute 10 to attenuate the ball speed. In this way, it is possible to prevent a large number of balls from being inserted at one time, thereby reducing the impact applied to the ball insertion jig 4, the groove shoulder of the screw groove 22, and the balls due to the falling of the ball by its own weight. Thus, scratches and the like can be prevented.
[0021]
As shown in FIG. 7, for example, ball plungers 17 a to 17 e are used for clamping the nut 1 by the floating mechanism 70. The ball plunger 17a can easily hold the nut 1 by pushing the upper end arc portion 30 of the nut 1 obliquely downward with a spring. Of course, a clamp mechanism such as air may be used to hold the nut 1.
[0022]
In the floating mechanism 70, a micrometer 18a is used so that the eccentric amount of the nut 1 with respect to the temporary shaft 3 can be finely adjusted. For example, as shown in FIG. 6, using a uniaxial slide 19, when the ball is introduced, the center of the nut 1 is pulled to the left with a spring (not shown) or the like with respect to the center of the temporary shaft 3. Is shifted with respect to the temporary shaft 3 to narrow the gap between the nut 1 and the right side of the temporary shaft 3. At this time, since the temporary shaft 3 rotates clockwise, the ball introduced from the ball insertion jig 4 is forcibly pushed into the screw groove 22.
[0023]
Further, the groove clearance on the ball rising side is widened to prevent the ball from running ahead and to continuously push up the ball. Thereby, the effect of continuously pushing up the balls in the circulation tube 25 can also be expected.
In other words, the nut 1 and the temporary shaft 3 are eccentric, so that the ball can be continuously raised while the ball is continuously raised, and the ball can be continuously enclosed. If the gap is too wide, the ball may be caught and protrude out of the circulation path. Therefore, a micrometer 18b is installed on the opposite side of the micrometer 18a so that the eccentric amount of the nut 1 can be adjusted. . Of course, the uniaxial slide unit 19 may be constituted by a linear guide device or the like. Further, it is desirable that the heads of both the micrometers 18a and 18b have a rotation preventing mechanism in the thimble part. In FIG. 7, 18a 'is a stopper on the micrometer 18a side, and 18b' is a stopper on the micrometer 18b side.
[0024]
The screw shaft right end support portion 8 is given a leftward force by a compression spring (moving means) 15, and the leftward force causes the temporary shaft center support portion 7 in the large-diameter shaft portion 3b of the temporary shaft 3 and the right end of the screw shaft. The screw shaft 2 is held between the support portions 8.
The temporary shaft support portion 9 is provided with an air cylinder 12 for positioning, for example. A micrometer 13 and a stopper 14 are used to adjust the movement range of the air cylinder 12, and the positioning of the taper step portion 21 of the temporary shaft 3 with respect to the guide surface 20 of the ball insertion jig 4 can be finely adjusted. The leftward force on the temporary shaft support portion 9 at this time is due to the spring force of the compression spring 15 of the screw shaft right end support portion 8, and the rightward force is given by the air pressure of the air cylinder 12.
[0025]
On the left end side of the passage portion where the ball chute 10 and the ball insertion jig 4 are in contact, the ball push bar 5 supported by the push bar support base 6 is disposed. A drive cylinder is attached to the push bar support base 6 as a power source for moving the push push bar 5 in and out. When it is confirmed by the ball check sensor 24 of the ball chute 10 that there is no ball, the ball push rod 5 is advanced to push out all the balls in the ball passage 26 of the ball insertion jig 4 and the drive cylinder of the push rod support base 6. This sensor detects that all the balls in the ball passage 26 have been pushed out.
[0026]
The ball push bar 5 stops in a state where the ball in the ball passage 26 of the ball insertion jig 4 is pushed out.
This is because all the balls remaining on the guide portion 20 a between the guide surface 20 of the ball insertion jig 4 and the taper step portion 21 of the temporary shaft 3 without being introduced into the screw groove 22 of the nut 1 are screwed on the nut 1. In order to push the air cylinder 12 up into the groove 22, the air cylinder 12 is retracted and the temporary shaft 3 is moved toward the small-diameter shaft portion 3 a by a half pitch, for example, by the spring force of the compression spring 15. In order to function as a lid that prevents the ball from returning again to the ball exit portion of the ball passage 26 by stopping the ball pushing rod 5 while it is pushed out at this time. It is. Note that air pressure may be used only for the return of the ball push bar 5 in consideration of ball scratches, and a spring (not shown) may be used for pushing.
[0027]
In order to prevent the tongue of the circulation tube 25 from interfering with the ball stopper 27 of the ball insertion jig 4 when the ball remaining on the guide portion 20a is moved over the taper step portion 21, the circulation tube of the ball stopper 27 is prevented. The surface facing the 25 exit side is a flat surface 29.
Next, the operation of the ball screw device assembling apparatus will be described.
[0028]
First, in order to align the nut 1 of the ball screw device (in this embodiment, a notch on the outer surface of the nut is used), the nut 1 is clamped by the floating mechanism 70 in accordance with the rail guide 31.
Next, the nut positioning air cylinder 33 is protruded, and the floating mechanism 70 is slid to the left to position the nut 1 with respect to the ball insertion jig 4. Thereafter, the screw shaft right end holding portion 8 is moved to the right against the urging force of the compression spring 15 to hold the screw shaft 2 with center support between the screw shaft right end holding portion 8 and the temporary shaft center support portion 7. . At this time, the eccentric amount of the nut 1 with respect to the temporary shaft 3 is adjusted by the micrometers 18a and 18b and the stoppers 18a 'and 18b' of the floating mechanism 70.
[0029]
Next, a predetermined number of balls cut out from the ball distribution / feeder are fed into the ball insertion jig 4 via the ball chute 10. The ball fed into the ball insertion jig 4 passes through the ball passage 26 of the ball insertion jig 4 and passes between the tapered step portion 21 of the temporary shaft 3 and the guide surface 20 of the ball insertion jig 4 from the ball outlet portion 23. It flows into the guide part 20a.
[0030]
Here, since the temporary shaft 3 is driven to rotate clockwise by the drive motor 11, the ball flowing into the guide portion 20 a falls along the guide surface 20 of the ball insertion jig 4 with its own weight, and the taper step of the temporary shaft 3. It is regulated by the portion 21 and smoothly introduced into the thread groove 22 of the nut 1.
Next, when it is confirmed by the ball confirmation sensor 24 of the ball chute 10 that there is no ball, the ball push-in rod 5 is advanced to push out all the balls in the ball passage 26 of the ball insertion jig 4, and the push-rod support base 6. It is detected that all the balls in the ball passage 26 have been pushed out by the sensor of the drive cylinder. The ball push-in bar 5 stops in a state where the push-in is completed and functions as a lid for the ball outlet 23.
[0031]
Next, the air cylinder 12 is retracted and the temporary shaft 3 is moved to the small diameter shaft portion 3a side by, for example, a half pitch by the spring force of the compression spring 15 so that the ball is inserted and not introduced into the thread groove 22 of the nut 1. All the balls remaining on the guide portion 20a between the guide surface 20 of the tool 4 and the taper step portion 21 of the temporary shaft 3 are moved over the taper step portion 21 and pushed up into the thread groove 22 of the nut 1 to The ball is held on the BCD of the thread groove 22 of the nut 1.
[0032]
Thereafter, when the nut positioning cylinder 33 is pulled back, the nut 1 is moved from the temporary shaft 3 to the screw shaft fitting position by the tension spring 16 attached to the floating mechanism 70, and a light tensile force is applied by the tension spring 16. Thus, the fitting of the nut 1 and the screw shaft 3 can be started by rotating the temporary shaft 3 and the screw shaft 2 counterclockwise by the drive motor 11 and matching the thread groove phases of the nut 1 and the screw shaft 2. It becomes possible.
[0033]
In addition, after the nut 1 is moved to the fitting position by the tension spring 16 in a state where the phases of the nut 1 and the screw shaft 2 are matched by a sensor or the like (not shown), the screw shaft 1 is rotated counterclockwise by the drive motor 11. The screw shaft 2 and the nut 1 can be fitted to each other. Further, using a clutch (not shown), when the screw shaft 2 and the nut 1 are in phase and fitting is started, the rotational force applied from the drive motor 11 is cut off, and the nut 1 is merely pulled by the tension spring 16. And the screw shaft 2 can be fitted.
[0034]
When the fitting between the nut 1 and the screw shaft 2 is completed, the ball screw device is assembled. Then, the ball screw device is moved to the right side against the urging force of the compression spring 15 together with the screw shaft right end support portion 8 to remove the ball screw device from the assembling device, thereby completing the assembling operation of the ball screw device. .
In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
[0035]
For example, in the above embodiment, the circulation tube is taken as an example of the circulation part, but the nut fixed on the top and bottom is rotated even when the phase of the circulation top changes for each circulation circuit like the top type. By clamping it as possible, it becomes possible to adjust the phase of the ball outlet 23 to the highest position of the circulating top, and assembly can be performed.
[0036]
Further, if the nut 1, the ball insertion jig 4, and the ball pusher bar 5 are all rotatable with respect to the temporary shaft 3, the ball is brought into the thread groove 22 of the nut 1 by the taper step portion 21 when the temporary shaft 3 is offset. The ball can be rolled into the screw groove 22 by its own weight without being pushed up, and the load on the ball can be reduced.
Further, in the above-described embodiment, the case where the ball screw device is assembled with the provisional shaft 3 disposed horizontally is taken as an example, but this assembling device can be assembled even if the entire inclination angle is freely set. . For example, if the entire device is inclined so that the ball insertion jig 4 is positioned higher than the nut 1 and the horizontal portion is eliminated from the ball insertion portion 26, the ball can be inserted by its own weight, so that the ball push-in 5 Becomes unnecessary, and the number of parts can be reduced. In this case, a shutter or the like may be provided separately as a role of the lid of the ball outlet 23 when the temporary shaft 3 is offset.
[0037]
Furthermore, in the above embodiment, when all the balls remaining on the guide portion 20a get over the taper step portion 21, the temporary shaft 3 is offset to the left side by the repulsive force of the compression spring 15. However, apart from this, A structure in which the drive unit including the temporary shaft 3 is fixed and the ball insertion jig 4 is moved by a half pitch toward the screw shaft 2 together with the nut 1 may be employed.
[0038]
In this case, the ball pusher bar 5 is also moved by a half pitch together with the ball insertion jig 4. By fixing the drive unit including the temporary shaft 3, the compression spring 15 only supports the screw shaft 2, and the structure of the entire apparatus can be simplified. This method eliminates the burden on the compression spring 15 when used together with the structure in which the inclination angle of the entire apparatus described above is freely set, and the ball taper stepped portion 21 can be overcome with a lighter force. Can be done.
[0039]
Furthermore, in the above embodiment, the temporary shaft 3 is rotated by the drive motor 11, but the same ball introduction operation can be performed by installing a drive motor on the right end side of the screw shaft 2 and applying a rotational force. Can do. Further, the right end portion of the screw shaft 2 may be applied with a rotational force using a rotating chuck instead of center support.
Furthermore, in the above embodiment, the assembly is performed with the temporary shaft 3 and the screw shaft 2 joined, but after the temporary shaft 3 is supported or chucked alone, the ball is introduced into the nut 1 and after the introduction. The nut 1 and the screw shaft 2 may be fitted. In addition, if the multi-point positioning is performed not by the cylinder but by a motor or the like for positioning each support portion, the assembly process can be easily automated.
[0040]
Further, as shown in FIG. 8A, the entire outer peripheral surface of the temporary shaft 3 having the tapered step portion 21 is coated with an elastic body 3c, or urethane rubber or the like is used as an example of the elastic body 3c. By shrink fitting or adhering to the entire outer peripheral surface, when the temporary shaft 3 is rotated to allow the ball to flow in, a frictional force is applied to the ball so that it is not slippery. You may make it improve introduction efficiency. The same effect can also be obtained by embedding an elastic seal member such as an O-ring in the circumferential direction or the axial direction with respect to the outer peripheral surface of the temporary shaft 3.
[0041]
Further, as shown in FIG. 8B, the ball can be efficiently introduced into the nut 1 also by coating or embedding the elastic body 3c spirally on the outer peripheral surface of the temporary shaft 3 having the tapered step portion 21. Can do. Of course, the pitch of the elastic body, each lead, the amount of protrusion, the width, the winding direction, etc. at this time may be arbitrary. Similarly, the temporary shaft center support member 7 and the temporary shaft center support portion of the screw shaft right end support portion 8 can be coated with an elastic body to suppress slippage between the screw shaft 2 and the temporary shaft 3.
[0042]
【The invention's effect】
As is apparent from the above description, according to the present invention, since a predetermined number of balls can be smoothly introduced into the nut in a state where the circulating component is assembled to the nut, it is possible to improve work efficiency. . Further, by decentering the nut with respect to the temporary shaft when the ball is introduced into the nut, it is possible to continuously enclose the ball while preventing the ball from running ahead in the circulation path. Furthermore, the efficiency of introducing the ball into the nut can be increased by applying, embedding, shrink fitting or adhering the elastic body to the outer peripheral surface of the temporary shaft having the tapered step portion.
[Brief description of the drawings]
FIG. 1 is a plan view for explaining an assembly device for a ball screw device as an example of an embodiment of the present invention;
FIG. 2 is a front view of FIG. 1;
3A is a diagram for explaining a ball insertion jig, FIG. 3B is a diagram viewed from the right side of FIG. 3A, and FIG. 3C is a diagram viewed from the upper side of FIG.
FIG. 4 is an explanatory view for explaining a main part of the assembly device of the ball screw device, and is an explanatory sectional view of a view of the nut and the ball insertion jig as viewed from the side.
5A is an explanatory sectional view of a view of a nut and a ball insertion jig as viewed from above, and FIG. 5B is a sectional view taken along line AA in FIG.
6A is an explanatory view for explaining the operation of the assembly device of the ball screw device, and is an explanatory cross-sectional view of the nut and the ball insertion jig as viewed from the side, and FIG. It is a BB line sectional view of).
FIG. 7 is an explanatory diagram for explaining a floating mechanism.
8A and 8B are diagrams for explaining another embodiment of the present invention, in which FIG. 8A is a diagram showing a state in which an elastic body is disposed on the entire outer peripheral surface of the temporary shaft, and FIG. 8B is an outer periphery of the temporary shaft. It is a figure which shows the state which has arrange | positioned the elastic body helically on the surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Nut 2 ... Screw shaft 3 ... Temporary shaft 3a ... Small diameter shaft part 3b ... Large diameter shaft part 3c ... Elastic body 4 ... Ball insertion jig 11 ... Drive motor (drive means)
12 ... Air cylinder (moving means)
15 ... Compression spring (moving means)
20a ... Guide part 21 ... Tapered step part 22 ... Nut side thread groove 23 ... Ball outlet part 25 ... Circulation tube (circulation part)
26 ... Ball passage 27 ... Ball stopper 28 ... Protrusions

Claims (5)

  A nut of a ball screw device in which a circulating part is assembled in advance to a temporary shaft having a tapered step portion between a small diameter shaft portion and a large diameter shaft portion is loosely fitted, and in this state, between the temporary shaft and the nut. The ball insertion jig and the taper step portion are inserted by inserting a ball insertion jig into the small-diameter shaft portion side and rotating the temporary shaft with a predetermined number of balls inserted from the ball passage of the ball insertion jig. Between the screw groove of the nut and the temporary shaft through a guide portion formed between the nut and the temporary shaft, and then the small diameter is relatively set with respect to the nut and the ball insertion jig. The ball positioned on the guide portion by moving to the shaft side is moved over the taper step portion and introduced between the screw groove of the nut and the temporary shaft, and then the screw shaft of the ball screw device is inserted into the nut. Ball screw device characterized by fitting Assembly method.   2. The method of assembling a ball screw device according to claim 1, wherein when the ball is introduced between the screw groove of the nut and the temporary shaft, the nut is eccentric with respect to the temporary shaft. A temporary shaft nut in advance circulating component only was ball screw unit assembling has a tapered step portion between the small-diameter shaft portion and the large diameter shaft portion is loosely fitted, drive means for rotating the tentative shaft And a ball passage that is fitted from the small-diameter shaft portion side between the temporary shaft and the nut and into which a predetermined number of balls are inserted, and the ball that has come out of the ball passage is inserted into the thread groove of the nut and the nut A ball insertion jig having a guide surface for forming a guide portion between the provisional shaft and the tapered step portion ; and the provisional shaft relative to the nut and the ball insertion jig. And a moving means for moving to the small-diameter shaft portion side. A ball stopper is provided on the ball outlet side of the ball passage of the ball insertion jig to prevent the ball coming out of the ball passage from interfering with the ball introduced into the thread groove of the nut prior to the ball. Rutotomoni provided outlet of the to partition between the guide portion, the tip of the ball stopper projections for guiding the guide portion between the ball out from the ball passage and the tapered stepped portion of the guide surface assembling apparatus of the ball screw device according to claim 3, characterized in that provided in the part.   The ball screw device assembling apparatus according to claim 3 or 4, wherein an elastic body is applied, embedded, shrink-fitted or bonded to an outer peripheral surface of the temporary shaft having the tapered step portion.

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