JPH0453478Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a ball screw in which a cover member is disposed at the end of a nut to transport and circulate balls.

[Conventional technology]

Conventionally, this type of ball screw was developed in 1988.
As shown in Publication No. 67662, a nut is provided with a through hole in the axial direction that serves as a return passage for returning and circulating the balls into the nut which is externally fitted onto the screw shaft via a plurality of balls, and the through hole is open. A conveyance passage is provided in the lid member connected to the end so that the spiral passage formed between the screw shaft and the nut and in which the ball rotates communicates with the through hole to obtain rotational circulation of the ball. .

[Problem that the invention attempts to solve]

However, since the joint surface of the lid member is provided with grooves and holes to form a conveyance path, it is difficult to accurately and reliably connect the grooves and holes that form the conveyance path, the through hole provided in the nut, and the spiral path. The nut and the lid member are provided with large concave and convex portions on their joint surfaces in order to meet the requirements of the ball screw, which complicates the structure of the ball screw and makes it difficult to manufacture, resulting in an increase in cost.

This invention solves these problems,
The object of the present invention is to provide a ball screw in which the ball is conveyed on the nut side, the structure of the joint between the nut and the lid member is simplified, and good rotational circulation of the balls is obtained. .

[Means for solving problems]

For this reason, the present invention has a screw shaft with a spiral ball groove on the outer peripheral surface, and a spiral ball groove on the inner peripheral surface that can be fitted externally to the screw shaft and corresponds to the ball groove of the screw shaft. comprising a nut and a plurality of balls rotatably filled into a spiral passage formed by both ball grooves formed by externally fitting the nut onto a screw shaft;
The nut is provided with a through hole that serves as a return path for returning and circulating the balls rotating in the spiral path, which penetrates the inside in the axial direction and opens at the end surface where the ball groove on the inner peripheral surface unwinds. , a guide groove that communicates between the ball groove on the inner circumferential surface and the through hole and allows the ball to rotate is provided recessed from the end surface, and the open end that communicates with the guide groove of the through hole has a diameter larger than that of the through hole on the open side. The guide groove is provided in a straight line that connects tangentially to the ball groove on the inner peripheral surface of the nut, and a plate-shaped cover member is connected to the end of the nut to form the guide groove. A conveying piece is provided on the surface of the lid member that connects with the nut to protrude into the guide groove to enable ball conveyance between the ball groove of the screw shaft and the guide groove. A protrusion is formed in a progressively reduced shape toward the tip side corresponding to the bore and is fitted into the counterbore. The notch is provided in a substantially semicircular shape so that the lid member can be positioned without inhibiting rotation.

[Effect]

In the structure of the present invention, the ball rotating in the spiral passage formed between the screw shaft and the nut is conveyed from the ball groove of the screw shaft to the guide groove at the end of the nut by the conveying piece of the lid member, and is transferred to the through hole. The balls in the through hole are conveyed from the guide groove to the ball groove of the screw shaft by the conveying piece of the lid member and recirculated. With this action, the ball groove forming the ball circulation passage, the guide groove, and the through hole are easily aligned and can be easily installed due to the ball conveyance action on the nut side, eliminating the need for firm positioning of the cover member relative to the nut. The protrusion provided on the lid member, which is inserted into the counterbore provided on the nut to position the lid member, can be small in shape, and the structure of the joint between the nut and the lid member can be simplified and a good ball shape can be achieved. Rotational circulation can be obtained.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Figures 1 to 7, 1 is a screw shaft;
Two spiral ball grooves 2 of the same lead are provided on the outer peripheral surface. Numeral 3 is a nut that can be fitted onto the screw shaft 1, and has a spiral ball groove 4 on its inner peripheral surface corresponding to the ball groove 2 of the screw shaft 1. A spiral passage is formed. Reference numerals 5 and 6 denote through holes that are disposed inside the nut 3 so as to face the shaft core and penetrate in the axial direction. It forms a return passage for returning and circulating a plurality of filled balls 7 rotatably into the spiral passage formed therebetween. 8,9,10,1
Reference numeral 1 denotes a guide groove that forms a ball conveyance path between the spiral path and the return path, and the ball 7 rotates by communicating between the two ball grooves 4 on the inner peripheral surface of the nut 3 and the through holes 5 and 6 at both ends of the nut 3. It is movably provided recessed from the end face, and is provided in a linear shape that connects to the ball groove 4 in a tangential direction. 12, 13, 14, and 15 are counterbore portions provided at the opening ends of the through holes 5 and 6 that communicate with the guide grooves 8, 9, 10, and 11, and are made to have a larger diameter than the through holes 5 and 6 and sequentially move toward the opening side. It is formed into an enlarged shape. Reference numerals 16 and 17 are cover members, and a plurality of tightening bolts 1 are attached to both ends of the nut 3.
8, 19 and guide grooves 8, 9, 1
0 and 11 form a conveyance path for the ball 7. The lid members 16 and 17 are capable of being screwed together with the screw shaft 1, and have two protruding helical seal portions 20 and 21 formed on their inner circumferential surfaces in correspondence with the ball grooves 2 of the screw shaft 1. The guide groove 8 of the nut 3 is connected to the helical seal portions 20 and 21 on the joint surface.
9, 10, 11, and protruding conveyor pieces 22, 23 are provided to enable ball conveyance between the ball groove 2 of the screw shaft 1 and the guide grooves 8, 9, 10, 11, respectively. 24, 25, 26, ... are the lid members 16,
17 is a protrusion for positioning that protrudes from the joint surface with the nut 3, and is formed in the end face of the nut 3 in a sequentially reduced shape toward the tip side facing the opening counterbore parts 12, 13, 14, and 15. The shape is approximately semicircular so that the cover members 6 and 7 can be positioned without blocking the rotation of the ball 7 between the through holes 5 and 6 and the guide grooves 8, 9, 10, and 11 by fitting into the counterbore. A notch is provided in the.

Next, the operation of this configuration will be explained.

In the assembled state shown in FIGS. 1 and 2, when the screw shaft 1 is now rotated in the left direction of the arrow F, a plurality of fillers are filled into the two spiral passages formed between the screw shaft 1 and the nut 3. The ball 7 rotates in the ball groove 2 of the screw shaft 1 to convey the conveying pieces 22 and 23 of the lid member 16.
are conveyed to the guide grooves 8, 9 and circulated to one of the through holes 5, 6 (the left end in FIG. Through the ball groove 2 of the screw shaft 1
circulates. Further, when the screw shaft 1 is rotated in the direction opposite to the arrow F, the plurality of balls 7 filled into the spiral passage are rotated in the opposite direction to that described above, and the conveying piece of the lid member 17 moves the balls 7 into the ball groove of the screw shaft 1. From guide groove 10,1
1 and circulated to the through holes 5 and 6, and further circulated from the through holes 5 and 6 to the ball groove 2 by the guide grooves 8 and 9 and the conveying pieces 22 and 23 of the lid member 16. The nut 3 moves in the left-right axial direction along the lead of the spiral ball groove 2 in accordance with the rotational direction of the screw shaft 1.

In this operation, the conveying action of the ball 7 is obtained by the guide grooves 8, 9, 10, 11 provided at the end of the nut 3. 10, 11 and through hole 5,
The counterbore portions 12, 13, 14, 15 can be easily installed by accurately matching the holes 6, and eliminate the need for firm positioning of the cover members 16, 17 with respect to the nut 3.
The projections 24, 25, 26, .
rotational circulation can be obtained. Further, since the guide grooves 8, 9, 10, and 11 are provided in a linear shape that connects to the ball groove 4 in the tangential direction, the guide grooves 8, 9, 10, and
The balls 7 that rotate and circulate through the guide grooves 8, 9, 10, and 11 are not easily pressed against the side walls of the guide grooves 8, 9, 10, and 11, and the balls 7 can rotate and circulate smoothly. Furthermore, since the cover members 16 and 17 are not provided with guide grooves in which the balls 7 rotate and circulate, they can be made into a thin plate shape that is not affected by the acting force caused by the rotation and circulation of the balls 7, and the entire ball screw can be made small and It can be made lighter. Furthermore, the projections 24, 25, 26,
... into the counterbore portions 12, 13, 14, 15 provided at the open ends of the through holes 5, 6 to form the lid member 16,
17, the protrusions 24, 2
5, 26, ... are inserted into the counterbore portions 12, 13,
14 and 15 can be provided using the through holes 5 and 6, and the problem of the present invention can be achieved even if the counterbore is provided separately from the through holes, but compared to this, the structure is simpler. can be achieved. Furthermore, the counterbore portions 12, 13, 14, 15 are sequentially enlarged toward the opening side, and the protrusion portions 24, 2
5, 26, ... as counterbore parts 12, 13, 14, 1
Since the protrusions 24, 25, 26, . , 17 can be easily positioned.

[Effect of idea]

As described above, according to the present invention, there is a screw shaft having a spiral ball groove on the outer peripheral surface, and a spiral ball groove on the inner peripheral surface that can be fitted externally to the screw shaft and corresponding to the ball groove of the screw shaft. The nut is equipped with a plurality of balls rotatably filled into a spiral passage formed by both ball grooves formed by externally fitting the nut onto a screw shaft. A through hole that serves as a return passage for returning and circulating the rotating ball is provided in the interior in the axial direction and opened at the end surface from which the ball groove on the inner circumferential surface unwinds. A guide groove that communicates with the through hole and allows the ball to rotate is provided recessed from the end surface, and a seat is formed at the open end that communicates with the guide groove of the through hole with a diameter larger than that of the through hole and gradually expands toward the opening side. A hollow portion is provided, a guide groove is provided in a straight line that connects tangentially to the ball groove on the inner circumferential surface of the nut, and a plate-shaped cover member is bonded to the end of the nut to form a ball conveyance path with the guide groove. A conveying piece is provided on the joint surface of the lid member with the nut to protrude into the guide groove to enable ball conveyance between the ball groove of the screw shaft and the guide groove. The protrusion is formed into a progressively reduced shape and is fitted into the counterbore.The protrusion is fitted into the counterbore to close the lid without blocking the rotation of the ball between the through hole and the guide groove. By providing a substantially semicircular notch to ensure positioning of the member, the ball groove, guide groove, and through hole that form the ball circulation passage can be easily provided in exact alignment with the nut side. Good rotational circulation of the ball can be obtained.

In addition, since the guide groove is provided in a linear shape that connects tangentially to the ball groove on the inner circumferential surface of the nut, the balls rotating and circulating in the guide groove are less likely to be pressed against the side walls of the guide groove, allowing the balls to rotate smoothly. Can be circulated. Furthermore, since the lid member does not have a guide groove in which the balls rotate and circulate, it can be made into a thin plate shape that is not affected by the acting force caused by the rotation and circulation of the balls, making it possible to reduce the size and weight of the entire ball screw. Wear.
Furthermore, since the lid member is positioned by fitting the projection provided on the lid member into the counterbore provided at the open end of the through hole, the counterbore into which the projection is inserted utilizes the through hole. Although the problem of the present invention can be achieved even if the counterbore is provided separately from the through hole, the configuration can be simplified compared to this. Furthermore, the counterbore portion is formed in a sequentially enlarged shape toward the opening side, and the protrusion portion is formed in a sequentially contracted shape toward the distal end side corresponding to the counterbore portion, so that the protrusion portion is It has the effect that it can be easily fitted into the counterbore and the lid member can be easily positioned.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a ball screw, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. A sectional view of the ivy nut, FIG. 4 is a side view as seen from the left side of FIG. 3, FIG. 5 is a front view of the lid member, FIG. 6 is a side view as seen from the left side of FIG. 5, and FIG. The figure is a sectional view taken along the line - in FIG. 1... Screw shaft, 2, 4... Ball groove, 3... Nut, 5, 6... Through hole, 7... Ball, 8,
9, 10, 11... Guide groove, 16, 17... Lid member, 22, 23... Conveyance piece.

Claims (1)

[Scope of utility model registration request] A screw shaft with a spiral ball groove on the outer circumferential surface,
A nut that can be externally fitted onto a screw shaft and has a spiral ball groove on its inner peripheral surface that corresponds to the ball groove of the screw shaft, and a spiral formed by both ball grooves that are formed by externally fitting the nut onto the screw shaft. The nut is provided with a plurality of balls that are rotatably filled into the spiral passage, and the nut has a through hole that is axially penetrated inside to form a return passage for returning and circulating the balls rotating in the spiral passage. The ball groove on the inner circumferential surface is provided with an opening at the end surface from which it unwinds, and a guide groove is provided recessed from the end surface so that the ball can rotate by communicating the ball groove on the inner circumferential surface and the through hole. A counterbore is provided at the opening end communicating with the guide groove of the nut, which has a diameter larger than that of the through hole and gradually expands toward the opening side, and the guide groove is formed in a straight line that connects tangentially to the ball groove on the inner peripheral surface of the nut. A plate-shaped lid member is connected to the end of the nut to form a ball conveyance path with the guide groove, and a plate-shaped lid member is positioned in the guide groove on the joint surface of the lid member with the nut and is connected to the ball groove of the screw shaft. A conveying piece is provided to protrude to enable ball conveyance between the guide grooves, and a protrusion is provided to protrude and be formed in a progressively reduced shape toward the tip side corresponding to the counterbore to fit into the counterbore. A ball screw is provided with a substantially semicircular notch so that the cover member can be positioned without blocking the rotation of the ball between the through hole and the guide groove when inserted into the counterbore.