JP2000074172A - Molding nut, manufacture of molding nut, and linear guide device using molding nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding nut which can be fabricated through a manufacturing process easy and of simple configuration and can be pressed uniformly to the whole peripheral circumferential surface of a screw shaft. SOLUTION: This molding nut 2 to be fitted on a screw shaft 1 is formed through a die shaping process from a resilient material and is furnished with a slot 3 over the whole length in the axial direction so that the nut 2 is split in the circumferential direction. When fitted on the screw shaft 1, the nut 2 will have the same effective diameter substantially as the effective diameter of the screw shaft 1, and the nut 2 is equipped with an elasticity directed toward the center in the radial direction of the screw shaft 1. The slot 3 is either formed by making molded threads using a die and core followed by machining, or putting a core and a slotting core in a die followed by injection molding. The nut 2 is used in a linear guide device and equipped with a stable accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded nut, a method of manufacturing the molded nut, and a linear feeder using the molded nut. The production is particularly easy, and the molded nut and the molded nut are screwed. The gap error in the axial direction with the screw shaft can be absorbed, and even if used for a long time, the gap between the molded nut and the screw shaft can be kept constant, resulting in a partial gap or contact with the screw shaft. TECHNICAL FIELD The present invention relates to a molded nut, a method for manufacturing a molded nut, and a linear guide device using the molded nut, which can provide stable contact torque (torque) without giving undesired contact resistance (preload).

[0002]

2. Description of the Related Art Generally, as a feed screw device, a slide screw device in which a screw shaft and a nut are in sliding contact, and a ball screw device in which a ball is interposed between a screw shaft and a nut are known. The sliding screw device has an advantage that its structure is simple, and it is easy to reduce the size, weight, and cost, and it is used for a device that does not require a high degree of feed accuracy.

[0003] However, in such a sliding screw device, since the screw shaft and the nut are in contact with each other by sliding, abrasion occurs between the screw shaft and the nut due to wear.
An axial clearance may be generated between the screw shaft and the nut, and there is a problem that the clearance is increased by repeated use and positioning accuracy is deteriorated.

[0004] Therefore, in order to prevent the generation of an axial clearance due to the wear and stabilize the torque required for rotation of the nut, a nut provided with a flange portion and a cylindrical portion and screwed with a screw shaft has the following features. A nut has been proposed in which a flexible material is used, a slit is formed in the cylindrical portion of the nut along the axial direction, and a member having a spring property is mounted on the outer periphery of the nut. No. 7558).

[0005] In the sliding screw device according to this example, as shown in FIG. 12, a nut 102 screwed to a screw shaft 101 is entirely made of a flexible material such as synthetic resin or natural rubber. A flange portion 103 having a passage along a mounting bolt is provided at a central portion, and a nut cylindrical portion 104 is provided on both sides of the flange portion.
Are formed integrally, and a female screw portion 108 screwed to the screw shaft is formed over the entire length thereof.

[0006] The nut cylindrical portion 104 is provided with a slit 105 that penetrates in the radial direction and extends in the axial direction. In this example, four slits 105 are provided at equal intervals on the circumference, and the nut cylindrical portion 104 has four portions 104 a to 104 cantilevered by the flange portion 103.
104d.

[0007] The nut 102 has flexibility in itself and is further softened in the radial direction due to the formation of the slit 105. On the outer periphery of each cylindrical portion 104 on both sides of the flange portion 103, an annular concave groove 106 is formed at an intermediate position in the axial direction, and the concave groove 106 is used to bend the nut last week inward in the radial direction. A garter spring 107 as a member having a spring property in the circumferential direction is mounted.

When the nut 102 is screwed onto the screw shaft 101 by the garter spring 107, the screw shaft 1
The external thread of No. 01 is always screwed tightly, and even if the nut or the thread groove of the external thread is worn by use, the amount of wear is absorbed by the bending of the nut 102, and there is no backlash for a long time, and the initial engagement accuracy is maintained. It will be.

[0009]

However, in the above-mentioned conventional nut 102, a garter spring 107 must be attached as a member having spring properties around the nut cylindrical portion 104 of the nut 102. There is a problem in that the structure is complicated, and an assembling and assembling process is required, which increases the cost.

[0010] In addition, each of the portions 104a to 104d of the nut cylindrical portion 104 in which the slit 105 is formed is strongly pressed against the screw shaft 101 by a garter spring 107 in the vicinity of the center in the circumferential direction between the slit 105. Is done. On the other hand, each part 104a-
The circumferential end of 104d is pressed by the screw shaft more weakly than the central portion, and the amount of wear is uneven in the circumferential direction of the cylindrical portion 104.

Further, in the nut 102, each portion of the cylindrical portion 104 divided by the slit 105 is supported by the flange portion 103 in a cantilever manner, and the garter spring 1
Since it is in a state of being urged inward in the diameter direction at 07,
There is a problem that the pressing force against the screw shaft is not uniform depending on the distance from the flange portion 103, and the pressing force is reduced when the nut 102 is worn.

For this reason, as described above, in places where the pressing force is large, abrasion proceeds more easily than in other places, and looseness occurs between the screw shaft 101 and the nut 102,
Galling may occur due to wear powder.

Therefore, the present invention has a simple structure, can be manufactured in an easy manufacturing process, is uniformly pressed on the entire circumference of the screw shaft, and is in a state before the nut is worn even if the nut is worn. An object of the present invention is to provide a molded nut, a method of manufacturing the molded nut, and a linear guide device using the molded nut, which can reduce the change in the pressing force as compared with the above.

[0014]

According to the present invention, the following means are employed to solve the above-mentioned problems.

According to the first aspect of the present invention, there is provided a molded nut 2 screwed to a screw shaft 1 and molded from an elastic material. The molded nut 2 extends over the entire length in the axial direction. A split portion 3 that divides 2 in the circumferential direction is formed at one place, and the molded nut has an effective diameter substantially the same as the effective diameter of the screw shaft when screwed into the screw shaft; The molded nut 2 has elasticity in which the molded nut 2 is directed to the center in the radial direction of the screw shaft 1.

According to a second aspect of the present invention, there is provided a method for manufacturing a molded nut according to the first aspect, comprising the following steps. A mold clamping step of disposing a core 20 having a male screw 21 formed in a mold 10 including a movable mold 12 and a fixed mold 11; An injection step of pouring the molten material into the mold 10; A mold opening step of opening the mold 10 and removing the annular molded body 6. Core removing step of removing the core 20 while rotating the core 20. A cutting step of cutting and forming the split portion 3 having a constant width over the entire length of the molded body 8 in the axial direction.

According to a third aspect of the present invention, there is provided a method for manufacturing a molded nut according to the first aspect, comprising the following steps. A core 30 having a male screw 21 formed in a mold 10 including a movable mold 12 and a fixed mold 11;
Core 4 with constant width over the entire length
A mold clamping step of placing 0. An injection step of pouring the molten material into the mold 10; A mold opening step of opening the mold 10 and removing the molded body. A split core removal process for removing the split core 40. A core removing step of removing the core 30 while rotating it.

According to a fourth aspect of the present invention, there is provided a linear guide device provided with the molded nut according to the first aspect, wherein a table is mounted on a guide rail 51 having a U-shaped cross section via a rolling element 53. The rolling element 53 is movably supported so as to be sandwiched by the inner surface of the rail 51, and the rolling element 53 is rotatably interposed between rolling element rolling surfaces 54 provided between the table side and the guide rail inner surface facing each other. The table 52 is provided with the molded nut 2 according to claim 1, into which the feed screw shaft 1 is screwed.

[Operation] In the molded nut 2 according to the first aspect of the present invention, a split portion 3 for dividing the molded nut 2 in the circumferential direction is formed in one place over the entire length in the axial direction,
The molded nut has an effective diameter substantially the same as the effective diameter of the screw shaft when screwed onto the screw shaft 1, and turns the molded nut 2 toward the center in the radial direction of the screw shaft 1. Since the flank of the screw shaft 1 is made to have elasticity, the flank surface of the screw shaft 1 can be uniformly contacted in the axial direction and the circumferential direction, and uneven wear does not occur.

That is, the formed nut 2 has a split portion 3 formed over its entire length in the axial direction, and the formed nut 2 itself has elasticity directed toward the center in the radial direction of the screw shaft 1. 2 contacts the screw shaft 1 at any position along its axis with a uniform and uniform pressing force.

Furthermore, the split portion 3 is formed only at one place, and when the molded nut 2 is screwed onto the screw shaft 1, the effective diameter is substantially the same as the effective diameter of the screw shaft. Therefore, any position other than the split portion 3 contacts the screw shaft 1 along the circumferential direction of the molded nut 2 with a uniform pressing force without fluctuation.

Further, according to the method for manufacturing a molded nut according to the second aspect of the present invention, a material in which the mold 10 and the core 20 are clamped and melted is injection-molded, and the molded body is molded. 1
When the core 20 is removed from the molded body while rotating and removing the core, the molded body is cooled from the outer periphery, the inner periphery, and both side surfaces, and the annular molded body contracts in the direction of decreasing the diameter. However, although the compact shrinks, the shape of the compact becomes stable after a certain period of time (24 to 48 hours).

In the state where the molded body is contracted, in the circumferential direction, each part of the molded body has an internal stress remaining in a direction in which the radius of curvature of the molded body is reduced and used, and these internal stresses are reduced in the circumferential direction. As a whole, the molded body remains annular and does not deform.

In this state, when a split portion having a predetermined width is cut, the entire length of the molded body in the circumferential direction is shortened.
Due to the above-mentioned internal stress, the molded body is reduced in diameter, becomes annular in a state where both sides of the split portion are in contact with each other, and is in a state of being circumferentially suspended, thereby completing a molded nut. The diameter of the core 20 is used to solidify the molding material so that the effective diameter of the female screw formed on the completed molded nut 2 is slightly smaller than the effective diameter of the screw shaft to be screwed. It is set in consideration of the accompanying shrinkage. The cutting width of the split portion 3 is also set such that the effective diameter of the female screw formed on the molded body after cutting is slightly smaller than the effective diameter of the screw shaft 1 to be screwed.

The diameter of the core and the size of the cutting width of the split portion vary depending on the dimensions of the molded nut to be manufactured and the characteristics of the material.

The completed molded nut 2 is as described in claim 1, and when screwed into the screw shaft 1, the effective diameter is substantially the same as the effective diameter of the screw shaft.
Further, the molded nut 2 is configured to have elasticity that is directed toward the center in the radial direction of the screw shaft 1.

Further, according to the method for manufacturing a molded nut according to the third aspect of the present invention, the material melted into the mold 10, the core 30, and the split forming die 40 is injected. After molding, the molded body is removed from the mold 10, the core for forming a split portion 40 is further removed from the molded body, and the core 30 is further removed while rotating, so that the molded body contracts in a direction to reduce the diameter.

When the diameter of the split portion 3 is reduced by the width of the split portion 3 so that both surfaces of the split portion 3 are in contact with each other, a molded nut having a predetermined shape is completed.

The diameter of the core 20 is reduced so that the effective diameter of the female screw formed on the completed molded nut 2 is slightly smaller than the effective diameter of the screw shaft 1 to be screwed. It is set in consideration of the amount of shrinkage due to solidification of the material. The width of the split-section forming core 40 is also set such that the effective diameter of the female screw formed in the molded body is slightly smaller than the effective diameter of the screw shaft 1 to be screwed.

The diameter of the core 20 and the size of the split forming core 40 are determined by the dimensions of the molded nut to be manufactured.
Since it changes depending on the characteristics of the material, an appropriate one is selected by an experiment.

Then, the completed molded nut 2 is as described in claim 1, and when screwed into the screw shaft 1, the effective diameter becomes substantially the same as the effective diameter of the screw shaft.
Further, the molded nut 2 is configured to have elasticity that is directed toward the center in the radial direction of the screw shaft 1.

Further, according to the linear guide device 50 according to the fourth aspect of the present invention, the molded nut 2 according to the first aspect is used as a nut provided on the table 52 and screwed to the feed screw shaft 1. The effective diameter of the molded nut 2 is substantially the same as the effective diameter of the feed screw shaft 1;
In addition, the molded nut 2 has elasticity that is directed toward the center in the radial direction of the screw shaft 1. Therefore, since the flank surface of the feed screw shaft 1 can be uniformly contacted in the axial direction and the circumferential direction, uneven wear does not occur, and even if worn, the nut is always pressed uniformly in the radial direction. No clearance occurs in the axial direction, and a stable feed state can be always maintained.

That is, as described above, the molded nut 2 comes into contact with the screw shaft 1 with a uniform pressing force at any position along its axis, and the molded nut 2 is screwed into the screw shaft 1. When they are combined, they contact the screw shaft 1 along the circumferential direction of the molded nut 2 at any position other than the split portion 3 with a uniform pressing force without fluctuation.

Further, even if the molded nut 2 is worn, the molded nut 2 is constantly pressed in the center direction with an equal force, so that the molded nut 2 is always tightened in the center direction and is in contact with the male screw of the screw shaft 1. The gap in the axial direction is as small as possible, so that the play when moving the table 52 from one direction to the opposite direction can be reduced, and the movement accuracy of the table can be increased.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a molded nut, a method of manufacturing the molded nut, and a linear guide device using the molded nut according to the present invention will be described.

FIG. 1 shows an embodiment of a molded nut 2 according to the present invention. In this example, the molded nut 2 is die-cast with an elastic material, for example, a synthetic resin such as acetal / copolymer or polyimide, or a die-casting alloy such as zinc / aluminum.

In the present embodiment, the molded nut 2 is a nut cylindrical portion 4 having a female screw portion 5 screwed to the screw shaft 1.
And a flange 6 for attaching the molded nut 2 to a product is formed integrally with one end edge of the nut cylindrical portion 4 so as to extend outward. Reference numeral 7 denotes a plane portion for positioning the molded nut 2 formed on the flange portion 4.

The molded nut 2 is formed with a single linear split portion 3 that divides the molded nut 2 in the radial direction including the axis along the entire axial length including the nut cylindrical portion 4 and the flange portion. Have been. The split portion 3 can be formed by cutting an annular die-cast molded body, or can be formed by providing a die-casting mold with a core for forming a split portion.

When the molded nut is screwed onto the screw shaft, the formed nut has an effective diameter substantially equal to the effective diameter of the screw shaft 1 and the formed nut 2 has a radius equal to the radius of the screw shaft 1. It has elasticity that is oriented toward the center in the direction.

Therefore, according to the molded nut 2 according to the present embodiment, the split portion 3 is formed over the entire length in the axial direction, and the molded nut 2 itself has elasticity toward the center in the radial direction of the screw shaft 1. With such an arrangement, the molded nut 2 comes into contact with the screw shaft 1 with a uniform pressing force at any position along its axis without requiring any other member such as a spring.

Furthermore, the split portion 3 is formed only in one line, and when the molded nut 2 is screwed onto the screw shaft 1, the effective diameter becomes substantially the same as the effective diameter of the screw shaft 1. Along the circumferential direction of the molding nut 2, the screw shaft 1 is in contact with the screw shaft 1 at any position other than the split portion 3 with a uniform pressing force. For this reason, according to the molded nut 3 according to the present example, it is possible to uniformly contact the flank surface of the screw shaft 1 in the axial direction and the circumferential direction without adopting a complicated configuration such as combining other members, The occurrence of uneven wear can be prevented.

[First Example of Manufacturing Method of Molded Nut] FIG.
FIG. 5 to FIG. 5 show a first embodiment of a method for manufacturing a molded nut according to the present invention. The method for manufacturing a molded nut according to the present example is to produce an annular molded body using a die-casting mold, and then to cut and form a split portion 3 on the molded body to produce a molded nut 2.

In this example, as shown in FIG. 2, the movable mold 11 and the fixed mold 12 divided by a parting line 17 are provided.
Use a mold consisting of Actually, the movable mold 11 and the fixed mold 12 are arranged in a die casting apparatus in which these molds 11 and 12 are arranged. The mold 10 has a cavity 13 for forming the nut cylinder 4 and the flange 6,
14 and holes 15 and 16 for mounting the core.
In this example, the parting line 17 is aligned with the edge of the flange 6 on the nut cylinder forming side.

The core 2 to be assembled in the mold 10
0 is a male screw 21 for forming a female screw as shown in FIG.
Projecting portions 22 and 2 projecting from both sides of the male screw 21 and inserted into the core mounting holes 15 and 16 of the mold.
3 is provided.

The diameter of the male screw of the core 20 needs to be set in consideration of the contraction of the molded body and the contraction of the diameter due to the formation of the split portion 3 to be formed later. The setting of the diameter differs depending on the size of the molded nut 3 to be manufactured and the type of material, and is determined based on an appropriate value obtained in advance through experiments. still,
Reference numeral 24 designates a two-sided engaging member provided to face the projecting portion 23 so as to sandwich its diameter in order to engage a tool such as a wrench for rotating the core 20 when removing the core 20 from the molded body. Shows the joint face.

Then, the mold 10 is opened, the core 20 is inserted, the mold is closed, and as shown in FIG. 4, the mold 20 is assembled to the mold 10 by mold clamping (mold clamping step).

Next, a predetermined molten material is poured into the clamped mold from an injection port (not shown) (injection step).
As the material, the above-described synthetic resin or die-cast alloy is used as needed.

After the material has hardened, the mold 10 is opened and the annular molded body 8 is removed as shown in FIG. 4 (mold opening step). In the removed molded body 8, as shown in FIG.
The core 20 has been inserted.

Then, from the annular molded body 8 to the core 2
0 is removed while rotating (core removal process). This removal is performed by the two flat portions 7, 7 of the flange portion of the molded body 8.
The molded body 8 is fixed by sandwiching the space between them with a fixture such as a vise, and a tool such as a wrench is engaged with the two engagement surfaces provided on the core 20 to rotate the core 20. (A direction in FIG. 5).

The core 20 can be removed immediately after the movable mold 12 is separated from the fixed mold (the state shown in FIG. 4). Further, these core removing steps can be automated using a robot or the like.

Next, the molded body 8 from which the core 20 has been removed
Is cut with a constant width by a cutting tool such as a milling machine over the entire length in the axial direction to form a split portion 3 (cutting step). By this cutting, the molded body 8 is deformed so as to have a small radius of curvature over its entire circumference due to the stress remaining inside due to cooling, and is deformed inward in the diameter direction. Since the entire length of the molded body in the circumferential direction is shortened by the cut of the split part 3, the above-mentioned stress reduces the diameter of the molded body, and forms a circular shape with both surfaces of the split part in contact with each other. The nut is completed in the circumferential direction, and the molded nut is completed.

The diameter of the core 20 is set so that the effective diameter of the female screw formed on the completed molded nut 2 is slightly smaller than the effective diameter of the screw shaft to be screwed. Is set in consideration of the amount of shrinkage due to solidification of. With this set amount, the pressing force of the nut against the screw shaft can be set to a desired value. The cutting width of the split portion 3 is also set such that the effective diameter of the female screw formed on the molded body after cutting is slightly smaller than the effective diameter of the screw shaft 1 to be screwed.

The diameter of the core and the cutting width of the split portion vary depending on the size of the molded nut to be manufactured and the characteristics of the material. Therefore, appropriate values may be selected through experiments.

The completed molded nut 2 is the same as that described in the above section [Configuration of molded nut]. When screwed onto the screw shaft 1, the effective diameter is substantially the same as the effective diameter of the screw shaft. The molded nut 2 has an elasticity that is directed to the center in the radial direction of the screw shaft 1.

[Second Example of Manufacturing Method of Molded Nut] FIG.
FIG. 8 to FIG. 8 show a second embodiment of a method for manufacturing a molded nut according to the present invention. The method for manufacturing a molded nut according to the present example uses a die-cast molding including a core 30 and a split-section core 40, and manufactures a molded body in which the split portion 3 is formed only by the die-casting process. This is used as a molded nut 2.

In this embodiment, a mold 10 as shown in FIG. 2 is used as in the first embodiment. Since the details of this mold are the same as those in the first example, detailed description thereof will be omitted.

The core 3 to be assembled in the mold 10
As shown in FIGS. 6 (1) and 6 (2), reference numeral 0 denotes a male screw 31 for forming a female screw and protrudes on both sides of the male screw 31, and is inserted into the core mounting holes 15 and 16 of the mold. Protruding portions 32 and 33.

In this embodiment, the male screw 31 of the core 30 is provided with a groove 35 having a constant width in a straight line along the axis thereof, into which the split molding material 40 is fitted. I have.

The diameter of the external thread of the core 30 must be set in consideration of the deformation of the molded body due to the hardening and the contraction of the diameter by the split part 3 formed at the same time. The setting of the diameter differs depending on the size of the molded nut 3 to be manufactured and the type of material, and is determined based on an appropriate value obtained in advance through experiments. Reference numeral 34 denotes two surfaces provided opposite to each other with the diameter line of the protrusion 34 interposed therebetween for engaging a tool such as a wrench for rotating the core 30 when the core 30 is removed from the molded body. 3 shows an engagement surface.

The split cores 40 are shown in FIG.
As shown in (4), it is fitted into the groove of the core 30 and
Part 41 forming split part 3 in nut cylindrical part 4 of the molded body
And a portion 42 forming the split portion 3 in the flange portion 7 is a plate-shaped member integrally formed, and the shape contour is determined by the contour of the cavities 13 and 14 formed in the mold 10. The thickness (d in FIG. 6 (4)) is determined in advance by experiments or the like so that the molded nut 3 after molding is deformed to a predetermined diameter.

Then, the mold 10 is opened, the core 30 and the split core 40 are inserted, the mold is closed, and as shown in FIG. Mold 10
Perform mold clamping (mold clamping process).

Next, a predetermined molten material is poured into the closed mold from an injection port (not shown) (injection step).
As the material, the above-described synthetic resin or die-cast alloy is used as needed.

When the material has hardened, the mold 10 is opened, and the molded body 9 is removed (mold opening step). Molded body 9 removed
As shown in FIG. 8, the core 30 and the split core 4
0 has been inserted.

Next, the split core 40 is taken out, and this is performed by pulling out the split core 40 in the axial direction of the molded body 9. Thereafter, the core 30 is removed from the molded body 8 while rotating (core removal step). Further, these core removing steps can be automated using a robot or the like.

The molded body 9 from which the core 30 and the split core 40 are removed can be used as the molded nut 2 without any other processing because the fixed split 3 is formed. Here, the molded body 9 as the molded nut 2 is deformed inward in the diametrical direction over the entire circumference by the stress remaining inside due to cooling. That is, since the split part 3 is formed and the overall length of the molded body in the circumferential direction is shortened, the molded body is reduced in diameter by the above-mentioned internal stress, and becomes annular in a state where both surfaces of the split part are in contact with each other. It is in a state of being suspended in the circumferential direction, and has a female screw having a predetermined effective diameter.

That is, the effective diameter of the female screw formed on the completed molded nut 2 is set to be slightly smaller than the effective diameter of the screw shaft to be screwed in.
Is set in consideration of the amount of shrinkage due to solidification of the molding material. The thickness of the split core 40 for forming the split 3 is also set so that the effective diameter of the forming screw 3 is slightly smaller than the effective diameter of the screw shaft 1 to be screwed.

The diameter of the core 30 and the thickness of the split core 40 vary depending on the size of the molded nut to be manufactured and the characteristics of the material. I just need.

The completed molded nut 2 is the same as that described in the above section [Configuration of molded nut]. When screwed onto the screw shaft 1, the effective diameter is substantially the same as the effective diameter of the screw shaft. The molded nut 2 has an elasticity that is directed to the center in the radial direction of the screw shaft 1.

[Structure of Linear Guiding Device] FIGS. 9 to 13 show a linear guiding device 50 using the molded nut 2 according to the present invention.
1 shows an embodiment of the present invention. The linear guide device 50 according to the present example is configured such that the molded nut 2 described in the section [Configuration of the molded nut] is provided on the table 52 and screwed to the feed screw shaft 1 provided on the guide rail 51. Things.

That is, the table 52 is
And is transported by a feed screw shaft 1. The guide rail 51 has a U-shaped cross section.
Are supported so as to be sandwiched therebetween. As shown in FIGS. 11 to 14, the table 52 is provided with the above-described molded nut 2 at one end thereof, and the feed screw shaft 1 is screwed thereto. By screwing the forming nut 2 onto the feed screw shaft 1 in this manner, the feed screw shaft 1 is rotated, so that the table 52 is moved linearly along the guide rail 51.

Also, a single ball rolling surface 5 is provided on a surface facing the side surface of the table 52 and the inner surface of the guide rail 51.
The table 52 is configured to move smoothly by providing a number of balls 53, which are rolling elements, between the ball rolling surfaces 54, 55 so as to roll freely.

Here, the ball 53 is provided with a load passage 57 formed by the ball rolling surfaces 54 and 55 and a no-load passage penetrating in parallel with the load passage 57 along the axis of the table body 56. An endless track formed by end plates 60 and 61 disposed at both ends of the table main body 56 and connecting the load passage 57 and the no-load passage 59 to each other is configured. .

The reference numeral 80 in FIG.
1 shows a housing which is attached to one end of the feed screw shaft 1 and holds a ball bearing 81 which supports one end of the feed screw shaft 1. The housing 80 extends from the feed screw shaft 1 and is connected to a motor (not shown). The driving shaft 82 protrudes. Reference numeral 83 denotes a housing that is attached to the other end of the guide rail 51 and holds a plain bearing 84 that supports the other end of the feed screw shaft 1.

In the linear guide device 50 according to the present embodiment, the molding nut 2 is attached to an attachment hole 90 formed in one end surface of the table body 56 as shown in FIG. Then, the end plate 60 is attached to the table body 56.
, The molding nut 2 is fixed to the table. The flange portion 6 of the molded nut 2 is fitted into the mounting hole portion 90, and a flange engaging hole 91 is formed to be in contact with the flat portion 7 of the flange portion 6 and to prevent the molded nut 2 from rotating. ing.

Therefore, according to the linear guide device of this embodiment,
The nut to be screwed onto the feed screw shaft has an effective diameter substantially the same as the effective diameter of the molded nut 2 and has a resiliency in which the molded nut 2 is oriented toward the center in the radial direction of the screw shaft 1. Since the flank 2 is used, the flank surface of the feed screw shaft 1 can be uniformly contacted in the axial direction and the circumferential direction. Uneven wear does not occur, and a stable feed state can be always maintained.

Further, since the female screw of the molded nut 2 is pressed in the center direction by an equal force, the axial gap between the molded nut 2 and the male screw of the screw shaft 1 is equal to that of the molded nut 2. Is reduced as much as possible, the play when moving the table from one direction to the opposite direction can be reduced, and the movement accuracy of the table can be increased.

[0077]

As described above, according to the molded nut, the method of manufacturing the molded nut, and the linear guide device using the molded nut according to the present invention, the following effects can be obtained.

In the molded nut according to the first aspect of the present invention, a split portion for dividing the molded nut in the circumferential direction is formed at one place over the entire length in the axial direction, and the molded nut is attached to the screw shaft. When the screw nut is screwed, the effective diameter is substantially the same as the effective diameter of the screw shaft, and the molded nut is configured to have elasticity directed toward the center in the radial direction of the screw shaft 1. The first flank surface can be uniformly contacted in the axial direction and the circumferential direction, and uneven wear does not occur. Further, in the feed screw device in which the formed nut is screwed to the feed screw shaft, even if the formed nut is worn, it is always pressed toward the center of the screw shaft. The gap in the axial direction is as small as possible, the play in the axial direction when moving the table from one direction to the opposite direction can be reduced, and the moving accuracy of the feed screw device is high. It can be. And since the molding nut is integrated, it is possible to stabilize the accuracy of the product just by controlling the dimensions of the mold, and also to change the dimensions of the core etc. The molded nut used for the linear guide device (guide) can be manufactured at low cost without particularly requiring the assembling of other members.

Further, according to the method of manufacturing a molded nut according to the second aspect of the present invention, a material in which a mold and a core are clamped and melted is injection-molded, and the molded body is removed from the mold. ,
Furthermore, the molded nut according to claim 1 can be manufactured by removing the core from the molded body while rotating the core, cooling and solidifying the core, and cutting a split portion having a predetermined width dimension. Therefore, it is possible to obtain a molded nut capable of obtaining high moving accuracy without uneven wear with a small number of man-hours of one die-casting molding and cutting, and to produce a molded nut with low cost and high performance. it can.

Further, according to the method for manufacturing a molded nut according to the third aspect of the present invention, a material in which a mold, a core, and a split core are clamped is melt-molded, and injection-molded. The molded nut according to claim 1 can be manufactured by a step of extracting the molded body from the mold, further removing the split core from the molded body, further removing the core while rotating the core, and curing. . Therefore, it is possible to easily obtain a molded nut capable of obtaining high moving accuracy without uneven wear by only one die casting, and to produce the molded nut with high production efficiency and low cost.

Further, according to the linear guide device of the fourth aspect of the present invention, the molded nut according to the first aspect is used for the nut provided on the table and screwed to the feed screw shaft. The effective diameter of the formed nut is substantially the same as the effective diameter of the feed screw shaft, and the formed nut is
Are provided with elasticity directed toward the center in the radial direction. Accordingly, the molded nut can be brought into uniform contact with the flank surface of the feed screw shaft in the axial direction and the circumferential direction, so that uneven wear does not occur. Since it is constantly pressed in the center direction, it is possible to always maintain a stable feeding state. Further, since the female screw of the molded nut 2 is pressed in the center direction with an equal force, the axial gap between the molded nut 2 and the male screw of the screw shaft 1 is as small as possible. Thus, the play at the time of moving the table from one direction to the opposite direction can be reduced, and the movement accuracy of the table can be increased.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an embodiment of a molded nut according to the present invention, wherein (1) is a side view, and (2) is a half sectional front view showing the molded nut together with a screw shaft drawn by a virtual line.

FIG. 2 is a longitudinal sectional view showing a mold used in a first example of the embodiment of the method for manufacturing a molded nut according to the present invention.

FIG. 3 is a cross-sectional view showing a state in which a mold and a core are clamped in the first example of the embodiment of the method for manufacturing a molded nut according to the present invention.

FIG. 4 is a cross-sectional view showing a state in which a mold and a core are opened in the first example of the embodiment of the method for manufacturing a molded nut according to the present invention.

FIG. 5 is a sectional view showing a molded nut together with a core in a first example of the method for manufacturing a molded nut according to the present invention.

FIG. 6 is a view showing a core used in a second example of the embodiment of the method for manufacturing a molded nut according to the present invention, and (1)
Is a front view of the core, (2) is a side view from the ii direction in (1), (3) is a front view of the split core, and (4) is (3).
It is a side view from the iv direction inside.

FIG. 7 is a view showing a state in which the mold and the core are clamped in the second example of the embodiment of the method for manufacturing a molded nut according to the present invention, wherein (1) is a longitudinal sectional view, 2) is a sectional view taken along line ii-ii in (1).

FIG. 8 is a sectional view showing a molded nut together with a core in a second example of the method for manufacturing a molded nut according to the present invention.

FIG. 9 is a perspective view showing an embodiment of the linear guide device according to the present invention.

10 is a view showing the linear guide device shown in FIG. 9,
(1) is a plan view, and (2) is a sectional view taken along line ii-ii in (1).

FIG. 11 shows the linear guide device shown in FIG. 9 in FIG.
FIG. 3 is a sectional view taken along line XIII-XIII.

FIG. 12 is a partial sectional view showing a conventional formed nut together with a screw shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw shaft 2 Molding nut 3 Split part 10 Die 11 Fixed type 12 Movable type 20 Core 30 Core 40 Split core 50 Linear guide device

Claims (4)

[Claims] 1. A molded nut screwed onto a screw shaft and molded from an elastic material, wherein the molded nut has a split portion that divides the molded nut in the circumferential direction over the entire length in the axial direction. The molded nut is formed in one place, and when screwed into the screw shaft, the molded nut has an effective diameter substantially the same as the effective diameter of the screw shaft, and the molded nut is moved in the radial direction of the screw shaft. Molded nut with elasticity facing the center. 2. The method for producing a molded nut according to claim 1, comprising the following steps. A mold clamping step in which a core having an external thread is arranged in a mold composed of a movable mold and a fixed mold. An injection process of pouring a molten material into a mold. A mold opening process of opening the mold and removing the annular molded body. Core removal process that removes the core while rotating It is a cutting process that cuts and forms a split part with a constant width over the entire length of the molded body in the axial direction. 3. The method for producing a molded nut according to claim 1, comprising the following steps. A mold clamping step in which a core having an external thread formed in a mold composed of a movable mold and a fixed mold, and a split core having a fixed width over the entire length are arranged between the mold and the core. An injection process of pouring a molten material into a mold. A mold opening process that opens the mold and removes the molded body. Split core removal process to remove the split core. A core removal process that removes the core while rotating it. 4. A table which is movably supported by a guide rail having a U-shaped cross section so that the table is sandwiched by inner surfaces of the guide rail via rolling elements, and wherein the rolling elements are opposed to the table side and the guide rail which face each other. 2. The linear guide device according to claim 1, wherein the feed nut shaft is screwed to the table so as to be rotatably interposed between the rolling element rolling surfaces provided between the side surfaces.