JPH094691A - Nut, nut with housing and manufacture therefor - Google Patents

Abstract

PURPOSE: To form a dislocation in a prescribed phase at both thread parts of a central part by integrally-forming a first thin-wall and thick-wall part and a second thin-wall part of roughly cylindrical shape continuously out of a material with which a cavity is filled, and pulling out a threaded part of a movable core while rotating when solidification of filling material has reached a prescribed one. CONSTITUTION: On right and left of a cylindrical thick-wall part 6 in a roughly middle part of a nut 1 in the axial direction, a first and second thin-wall parts 2, 3 of roughly cylindrical shape are formed integrally with each other respectively. Inner surfaces of the first and second thin-wall parts 2, 3 are formed with a first and second female thread parts 4, 5 respectively, which are of an identical type and are positioned on an identical axial line, however, whose phases are dislocated from each other. A nut 1 is formed by die casting or the like, and a formed part is shrunk with cooling. A large amount of mold shrinkage occurs at the thick-wall part 6, and a small amount of mold shrinkage occurs at thin-wall parts 2, 3. An axial shrinkage is generated by use of a difference in the mold shrinkage amount, thus generating a phase dislocation between both thread parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nut for a precision screw transmission, a nut with a housing, and a method for manufacturing the same, which mutually convert linear motion and rotary motion.

[0002]

2. Description of the Related Art FIG. 8 shows a table feed mechanism using a conventional screw transmission, in which a screw shaft 11 is rotatably supported by a support side support unit 50 and a fixed side support unit 51, and a flange is attached to the screw shaft 11. Attached first nut 12 and second
The nut 13 is screwed. 1st nut with flange 12
And the second nut 13 is a housing (nut bracket,
The table mounting base 14) is inserted from both ends of the central stepped hole 15 and fixed to the housing 14 with bolts. Screw shaft 11
In order to accurately perform mutual conversion between the rotational momentum of the and the linear momentum of the housing 14, the axial clearance between the screw and the nut is reduced. There are various means to reduce the axial clearance between the screw and nut,
One of the means is shown in FIGS. 8 (a) and 8 (b). Second nut
The four mounting holes formed in the flange of 13 are round holes, while the four mounting holes formed in the flange of the first nut 12 are elongated holes 16 extending along the circumference. Therefore, after fixing the second nut 13 with a bolt, the first nut 12 is rotated clockwise or counterclockwise to move the second nut 13 and the first nut 12 together.
By shifting the phase with the nut 12, the axial clearance is eliminated, and while maintaining this state, the bolt inserted in the elongated hole 16 of the flange of the first nut 12 is tightened. In order to eliminate the axial clearance, for example, the left flank (slope) of the thread of the second nut 13 on the left side is pressed against the right flank of the thread of the screw shaft 11, and the first nut 12 on the right side The right flank surface of the thread is in a state of being pressed against the left flank surface of the thread of the screw shaft 11. In this case, the tensile force is applied to the first nut 12 and the second nut 13, but the same function can be achieved even if a compressive force is applied to the first nut 12 and the second nut 13.

In this way, the screw shaft 11, the first nut 12, the second
By combining with the nut 13, it is possible to reduce the axial clearance of the screw transmission. However, when the conventional first nut 12 and second nut 13 are used, the number of parts and the number of processed parts are large, and these parts are assembled so that the first nut 12 and the second nut 13 have a predetermined phase shift. It is considerably complicated to give the clearance, and the clearance adjustment is troublesome.

[0004]

The problem to be solved by the present invention is as follows.
To provide a nut made of die-cast metal or a synthetic resin material and having a predetermined phase shift in the threaded portions on both sides of the central portion, and a method for manufacturing the same. A nut and a method for manufacturing the same.

[0005]

According to the present invention, in a nut (1), a substantially cylindrical first thin portion (2), a thick portion (6) and a second thin portion (3) are adjacent to each other. The first female threaded portion (4) is formed integrally, and the first female threaded portion (4) and the second female threaded portion (5) are formed on the inner surfaces of the first thinned portion (2) and the second thinned portion (3), respectively. And the second female screw part (5) are located on the same axis with the same screw, there is a phase shift between the first female screw part (4) and the second female screw part (5), and the thick part Cutout on inner surface of (6)
(7) is formed, and the first female screw part (4) and the second female screw part (5) are formed.
The screw shaft (11) screwed to the above can be inserted into the cutout portion. The cutout portion (7) is provided so that the screw shaft can be screwed into the first female screw portion (4) and the second female screw portion (5), and the screw shaft resists the cutout portion (7). There is no limitation on the shape of the excision part (7) as long as it passes without being caught. The thick portion at the center of the nut is made thicker than the first thin portion and the second thin portion on both sides of the nut, and the first female screw portion and the second female screw portion are out of phase due to contraction after molding. In addition, a part or all of the threaded portion on the inner surface of the central thickened portion is cut off to reduce the axial clearance when the screw shaft is screwed, and the flange for connecting the housing has the central thickened portion. Can be arranged in the.

A first method for manufacturing a nut according to the present invention is a method for manufacturing a nut having the above-mentioned structure, which comprises (a) opening a mold and inserting a core having a threaded portion formed on the outer periphery thereof into the mold. Arranged,
Next, the first step of closing the mold, (b) the second step of filling and molding the molten material of die cast metal or synthetic resin into the cavity of the mold, (c) opening the mold, the core is at the center A third step of taking out a certain molded product from the mold, (d) a fourth step of holding the molded product and extracting it from the molded product while rotating the core.
(e) Due to the cooling of the molded product, the thick part of the center part shrinks more greatly than the thin parts on both sides, and the phase of the internal thread of one thin part deviates from the phase of the internal thread of the other thin part. Step (f) A sixth step of partially or completely cutting off the female screw portion on the inner surface of the thick portion. A second method for manufacturing a nut according to the present invention is a method for manufacturing a nut having the above-described structure, including (a) a first step of closing a mold, and (b) a molten material of die-cast metal or synthetic resin of a mold. The second step of filling and molding in the cavity, (c) the third step of extracting the movable core from the mold and the molded product while rotating the movable core, (d) opening the mold and removing the molded product from the mold Fourth step of taking out, (e) By cooling the molded product, the thick part in the center part shrinks more greatly than the thin parts on both sides, and the phase of the internal thread of one thin part of the internal thread of the other thin part It consists of a fifth step of shifting the phase, and (f) a sixth step of partially or completely cutting off the female screw portion on the inner surface of the thick portion.

According to the present invention, in the nut (38) with a housing, a through hole composed of a first medium diameter hole, a large diameter hole and a second medium diameter hole is formed in the housing, and the first medium diameter hole, the large diameter hole and the The first thin portion, the thick portion, and the second thin portion are integrally fixed adjacent to each other in the second medium-diameter hole, and the thick portion substantially at the center of the nut has the first thin portion and the second thin portion on both sides thereof. It is configured to be thicker than the thin portion, and contracts after molding so that the first thin portion
The internal threaded portion and the second female threaded portion of the second thin portion are out of phase, part or all of the threaded portion on the inner surface of the central thickened portion is cut off, and the axial clearance is reduced when the screw shaft is screwed. It is configured. A table fixing plane parallel to the axis of the screw shaft may be formed on the upper part of the housing, and the fastening means may be formed on the plane.
Further, the distance between the flat surface of the upper end of the housing and the axis of the screw shaft can be set to a predetermined height.

A first method for manufacturing a nut with a housing according to the present invention is a method for manufacturing a nut with a housing having the above-mentioned structure, which comprises (a) opening a mold, inserting the housing into the mold, The first step, in which the core having the threaded portion is inserted into the through hole of the housing and disposed in the mold, and then the mold is closed, (b) a molten material of die-cast metal or synthetic resin is applied to the mold. The second step of filling and molding in the cavity,
(c) Open the mold and take out the molded product with the housing with the core in the center from the mold, (d) Hold the housing and pull out from the molded product inside the housing while rotating the core. 4th step, (e) By cooling the molded product with housing, the thick part in the center part shrinks more greatly than the thin parts on both sides, and the phase of the female screw of one thin part of the other thin part It includes a fifth step of shifting the phase of the internal thread, and (f) a sixth step of partially or completely cutting off the internal thread part of the inner surface of the thick part. A second method for manufacturing a nut with a housing according to the present invention is a method for manufacturing a nut with a housing having the above-described configuration, which comprises (a) opening a mold and inserting a movable core into a through hole of the housing to open the housing. The first step is to insert the movable core, which is inserted into the mold and has the threaded portion formed on the outer periphery, into the mold, and then close the mold. (B) Die casting metal or synthetic resin molten material The second step of filling and molding in the cavity of the mold, (c) the third step of extracting the movable core from the molded product with the housing and the mold while rotating the movable core, (d) opening the mold and housing The fourth step of taking out the molded product with the mark from the mold, (e) By cooling the molded product with the housing, the thick part in the center part shrinks more than the thin parts on both sides, and the female screw of one thin part The phase of the female thread of the other thin part deviates from the phase Step (f) A sixth step of partially or completely cutting off the female screw portion on the inner surface of the thick portion. In addition, in the first and second manufacturing methods of the nut and the first and second manufacturing methods of the nut with housing, the purpose of partially or wholly cutting the female screw portion is that the screw shaft has the first female screw portion and the second female screw. This is because it can be screwed into the portion, and the shape of the portion to be cut off is not limited.

[0009]

According to the nut manufacturing method of the present invention, the substantially cylindrical first thin wall portion, the thick wall portion and the second thin wall portion are continuously and integrally formed by the material filled in the cavity, and the filling material When the solidification reaches a predetermined value, the threaded portion of the movable core is pulled out while being rotated, whereby female threads are formed on the inner surfaces of the first thin portion, the thick portion and the second thin portion. Since the axial molding shrinkage amount of the thick portion is larger than the axial molding shrinkage amount of the thin portion, when the molded product is cooled, the first thin portion and the second thin portion are attracted to each other, and The female screw portion of the first thin portion and the female screw portion of the second thin portion are out of phase, and after cooling, the screw portion on the inner peripheral surface of the thick portion of the molded product is partially or wholly cut off. When the nut thus obtained is screwed into the screw shaft, a screw feeder having no axial clearance is obtained. According to the method for manufacturing a nut with a housing of the present invention, the housing is used as an insert, the molten material of metal or synthetic resin is filled in the cavity, and the screw shaft is rotated when the solidification of the filled material reaches a predetermined value. While pulling out. A nut with a housing in which the above-mentioned nut is provided inside the housing is completed.

[0010]

FIG. 1 shows a nut 1 made of die-cast metal or synthetic resin, which is an embodiment of the nut of the present invention. The nut 1 has a cylindrical thick portion 6 at a substantially central portion in the axial direction.
A first cylindrical thin portion 2 and a second thin portion 3 each having a substantially cylindrical shape are integrally formed on the left and right sides of, respectively. First thin portion 2 and second
A first female screw portion 4 and a second female screw portion 5 are respectively formed on the inner surface of the thin portion 3, and the first female screw portion 4 and the second female screw portion 5 are located on the same axis with the same screw. Out of phase. The nut 1 is used for screw transmission,
A rotation stopping portion is arranged on the outer periphery of the thick portion 6. FIG.
In (a), the key groove 17 is a rotation preventing portion, and the key is fitted into the key groove 17. Further, in FIG. 1B, the insertion holes 19 formed in the flange portions 18 on both sides of the thick portion 6 are holes for inserting bolts, and the bolts are inserted into the insertion holes 19 so that the nut 1 is inserted into the housing. Etc. (similar to the housing 14 shown in FIG. 8 (a)).

The nut 1 is manufactured by injection molding, transfer molding, compression molding, etc. in die casting, plastic molding as described later, and the molded product undergoes molding shrinkage as it cools. 6 is large, and the first thin portion 2 and the second thin portion 3 are small. By utilizing this difference in the molding shrinkage amount, the first thin portion 2 and the second thin portion 3
The axial contraction is caused between the first and second internal thread portions 4 and the second internal thread portion 5, and a phase shift is caused. The nut 1 can be a nut for a screw transmission device.

There are two methods of manufacturing the nut of the present invention. The first manufacturing method is to dispose the fixed core parallel to the mold opening direction in the mold, and then pull out the core after taking out the molded product. Is a method characterized by. In addition, the second manufacturing method,
A method is characterized in that a movable core is arranged in a mold, the movable core is pulled out before taking out a molded product, and then the mold is opened to take out the molded product. The molding used in the first and second manufacturing methods includes injection molding, die casting, compression molding, transfer molding and the like.

With reference to FIG. 2, the first method of manufacturing the nut will be described separately for each step. The mold is manufactured in the first preparation step. Inside the first mold 20 and the second mold 21, there are two chamfered first support holes 26 for hanging a spanner, a first medium diameter cylindrical portion 52, a large diameter cylindrical portion 54, and a second medium diameter. The diameter cylindrical portion 53 and the second support hole 27 are continuously formed. First mold 20 and second
The core 22 arranged inside the mold 21 is a substantially cylindrical threaded portion.
23 and a first core support part 24 and a second core support part 25 having a double chamfer for integrally forming a spanner on the upper and lower sides thereof. The first core support part 24 and the second core support part 25 has a smaller diameter than the threaded portion 23. The first core support portion 24 and the second core support portion 25 of the core 22 are the first support holes 26 of the first mold 20 and the second core 21 of the second mold 21.
The first mold 20 and the second mold 21 are fitted and supported by the support holes 27.
A cavity 30 is formed by the core 22. The cavity 30 is a first medium diameter cylindrical portion whose outer surface is continuous from above.
52, the large-diameter cylindrical portion 54 and the second medium-diameter cylindrical portion 53, the upper and lower surfaces have annular flat surfaces, and the inner surface is formed by the screw portion 23. For example, the molten material injected from the injection molding machine is configured to fill the cavity 30 after passing through a nozzle touch portion, a sprue, a runner, and a gate (not shown).

According to the first step, the first die 20 and the second die
21 is opened, and the first core support portion 24 and the second core support portion of the core 22 are opened.
25 into the first support hole 26 and the second support hole 27,
The first die 20 and the second die 21 are closed, and the screw part 23 is provided on the outer peripheral portion.
A core 22 formed with is formed. The shape of the cavity 30 is substantially cylindrical and has a threaded portion 23 on the inner periphery, and the outer periphery has a shape in which a first medium diameter cylindrical portion 52, a large diameter cylindrical portion 54 and a second medium diameter cylindrical portion 53 are continuous. The upper side of the cavity 30 is the first
It is closed by a mold 20, and the lower side is closed by a second mold 21.

In the second step, the cavity is filled with the molten material and the nut is molded. For example, a molten material of die cast metal or synthetic resin injected from an injection molding machine passes through a gate or the like to fill the cavity 30, and the molten material is solidified to form a nut. In the third step, when the solidification of the filled material reaches a predetermined level (when the solidification has progressed to a certain degree and the molded product is taken out, there is no fear of deformation of the molded product), the first mold 20 and the 2 Open the mold 21 and insert the molded product with the core 22 in the center to the first mold 20 and the second mold.
Remove from mold 21.

In the fourth step, when the solidification progresses further and there is no fear of deformation of the molded product even if the molded product is held and the core 22 is pulled out, the molded product is held with a vise or the like and a spanner is applied. A wrench or the like having a double chamfered fitting hole is fitted to the first core support portion 24 or the second core support portion 25 of the core 22. While rotating the core 22 with a wrench, etc.,
Pull out 22. A female screw having substantially the same shape as the screw portion 23 is formed inside the molded product, and a semi-finished product including a substantially cylindrical thick portion and thin portions on both sides thereof is completed.

In the fifth step (cooling step, including the third step and the fourth step in terms of time), the semi-finished molded product undergoes molding shrinkage during cooling in the mold or after taking out, and the shrinkage occurs. The amount is larger in the thick part than in the thin part. For example, when the diameter of the support gate is 2 mm, the mold temperature is 80 degrees Celsius, and the resin temperature is 200 degrees Celsius, the 4 mm thick portion has a shrinkage ratio of 2.3 / 1000 in the axial and radial directions of 2 mm, which is thin. The shrinkage ratio of the part is 1.3 / 1000. Therefore, the thin portions on both sides of the thick portion are pulled in the axial direction due to the contraction of the thick portion, and the phase of the female screw of one thin portion is deviated from the phase of the female screw of the other thin portion.

In the sixth step, the female screw portion on the inner surface of the thick portion is partially or wholly cut to form a substantially annular cut portion 7, and the first female screw portion 4 and the second female screw portion 5 are formed. The screw shaft 11 to be screwed can be inserted into the excision portion 7, and the nut 1 (finished product) as shown in FIG. 1A is manufactured. The reason for cutting off the inner surface of the thick part is that the pitch of the internal thread of the thick part is smaller than the pitch of the internal thread of the thin part due to the contraction of the thick part, and the diameter of the internal thread of the thick part is thin. Since it is smaller than the diameter of the female screw of the thick portion, the screw shaft 11 screwed with the female screw of the thin portion cannot be screwed with the female screw of the thick portion. Therefore, the inner diameter of the thick portion is increased so that the screw shaft 11 is screwed into the first female screw portion 4 and the second female screw portion 5, but the screw shaft 11 does not come into contact with the thick female screw thread and the like. The inner surface of the thick portion is partially or completely cut off so as not to interfere with the above. The nut 1 shown in FIG. 1 (b) is also manufactured in the same manner as above.

The second method of manufacturing the nut will be described separately for each step with reference to FIG. The mold used in the second manufacturing method is configured so that it can be pulled out while rotating the movable core, and a part of the mold shown in FIG. 2 is modified. I will explain mainly. In the first mold 20 of FIG. 3, a withdrawal hole 29 having a diameter through which the screw portion 23 of the movable core 22 'can pass is formed from the upper end of the first intermediate diameter cylindrical portion 52 toward the upper side, and the withdrawal hole is formed. The top of 29 is the first
The upper surface of the mold 20 is opened. An insertion hole 57 that is substantially perpendicular to the axis of the extraction hole 29 is formed above the extraction hole 29, and the insertion hole 57 communicates with the cylinder tube 58. A piston 35 is slidably fitted in the cylinder tube 58, and a locking member 34 (piston rod) connected to the piston 35 is slidably inserted in an insertion hole 57. A pull-out member 31 with a spline is movably fitted in the pull-out hole 29.
When the locking hole 33 is located on the same axis as the insertion hole 57, the locking member 34 can be fitted and locked in the locking hole 33.
A first support hole 26 'is formed at the lower end of the pull-out member 31, the first support portion 24' of the movable core 22 'is fitted with the first support hole 26', and the first support portion 24 ' The extraction member 31 is connected by a pin. In addition, the second core support portion 25 'has the first support hole 27'.
It is supported rotatably. Spline of extraction member 31
32 is slidably fitted to a boss member 59, and the boss member 59 is rotatably supported via a ball bearing. A gear 60 is formed on the outer periphery of the boss member 59, and the gear 60 has a pinion.
61 meshes with each other, and the rotational force of the motor is transmitted to the boss member 59 via the pinion 61 and the gear 60. Other points are the same as those in FIG.

The second method of manufacturing the nut will be described separately for each step. Note that the same parts as those in the first manufacturing method of the nut will be denoted by the reference numerals in FIG. 2, and the description thereof will be simplified or omitted. By the first step, the first mold 20 and the second mold 21 are closed. By moving the piston 35, the locking member 34 is locked in the locking hole 33 of the extracting member 31, and the movable core 2
Keep 2'in place. The shape of the cavity 30 is
This is the same as in the first nut manufacturing method. In the second step, the cavity is filled with the molten material and the nut is molded. In the third step, when the solidification of the filled material reaches a predetermined level and there is no risk of deformation of the molded product even if the movable core is pulled out, the first mold 20 and the second mold 21 are held, and the motor To rotate. The rotating force of the motor is pinion 61, gear 6
It is transmitted to the movable core 22 'via 0, the boss member 59, the spline 32, the drawing member 31, the first supporting hole 26', and the first supporting portion 24 '. Since the screw part 23 of the movable core 22 'meshes with the female screw of the molded product, when the movable core 22' rotates, the movable core 22 'rotates.
22 ′ moves upward while rotating, and the movable core 22 ′ is extracted from the molded product, the first mold 20 and the second mold 21. First
Inside the moldings left in the mold 20 and the second mold 21,
A female screw having substantially the same shape as the threaded portion 23 is formed, and a semi-finished product formed of a substantially cylindrical thick portion and thin portions on both sides thereof is completed.

In the fourth step, when the solidification of the molded product progresses further and there is no fear of deformation of the molded product even if the molded product is taken out, the first mold 20 and the second mold 21 are opened, The semi-finished product is removed from the first mold 20 and the second mold 21. In the fifth step (cooling step, including the third step and the fourth step in terms of time), the semi-finished molded product undergoes mold shrinkage during cooling in the mold or after taking out, and the shrinkage amount is meat. The thick part is larger than the thin part. Therefore, the thin portions on both sides of the thick portion are pulled in the axial direction due to the contraction of the thick portion, and the phase of the female screw of one thin portion is deviated from the phase of the female screw of the other thin portion.

In the sixth step, the female screw portion on the inner surface of the thick portion is partially or wholly cut to form a substantially annular cut portion 7, and the first female screw portion 4 and the second female screw portion 5 are formed. The screw shaft 11 to be screwed can be inserted into the excision portion 7, and the nut 1 (finished product) as shown in FIG. 1A is manufactured. The other points are the same as in the first manufacturing method. The nut 1 shown in FIG. 1 (b) is also manufactured in the same manner as above.

FIG. 4 shows a state in which the nut 1 and the screw shaft 11 of the embodiment of the nut of the present invention are screwed together. First thin portion 2
Since the first female screw portion 4 and the second female screw portion 5 of the second thin portion 3 are out of phase with each other, the first female screw portion 4 in FIG.
The flank surface (slope) on the right side of the screw thread of the screw shaft 11 and the flank on the left side of the screw thread of the screw shaft 11 are in pressure contact, and the flank surface on the left side of the screw thread of the second female thread portion 5 and the right side of the screw thread of the screw shaft 11 Frank and pressure contact. In this way, the threads of the nut 1 and the threads of the screw shaft 11 are pressed against each other on the flank surfaces on both sides, so that there is no axial clearance.

FIG. 5 shows a nut with housing 38 of an embodiment of the nut with housing of the present invention. The nut 38 with a housing is obtained by fixing the nut 1 made of die cast metal or synthetic resin to the housing (nut bracket, holder block, table mount) 14 made of die cast metal. First medium diameter hole 40, large diameter hole in housing 14
A through hole 36 composed of 41 and the second medium diameter hole 42 is formed adjacent to each other on the same axis. First medium diameter hole 40, large diameter hole 41 and second
A first thin portion 2, a thick portion 6 and a second thin portion 3 made of, for example, a synthetic resin are integrally fixed adjacent to each other in the medium-diameter hole 42, respectively, and the first thin portion 2 and the second thin portion 3 are A first female screw portion 4 and a second female screw portion 5 are formed on the inner surface, respectively.
The first female screw part 4 and the second female screw part 5 are located on the same axis with the same screw, and there is a phase shift between the first female screw part 4 and the second female screw part 5. A substantially annular cutting portion 7 is formed on the inner surface of the thick portion 6, and the first female screw portion 4 and the second female screw portion 5 are formed.
A screw shaft screwed with and can be inserted into the excision portion 7.
A first annular portion 44 and a second annular portion 45 are continuously formed on both sides of the first thin portion 2 and the second thin portion 3, and the first annular portion 44 and the second annular portion 45 are formed by a strip-shaped portion 46 into the housing 14. Are integrally connected via the upper part of the. The strip portion 46 is shown in FIG.
Although it is also disposed in a groove portion 47 described later shown in (b), the strip-shaped portion 46
Is thinner than the height of the groove 47.

The nut 38 with a housing is used in a screw transmission, and when the screw shaft 11 is screwed, the relationship between the screw shaft 11 and the first female screw portion 4 and the second female screw portion 5 is that of the nut 1 shown in FIG. As in the case, there is no axial clearance. Although not clearly shown in FIG. 5, a screwing hole or the like for mounting a movable body (table or the like) is formed on the upper surface of the housing 14. Further, in practice, the first thin portion 2, the thick portion 6 and the second thin portion 3
The through hole 36, the first thin portion 2, the thick portion 6 and the second thin portion 3 are fixed in a state where the molding shrinkage occurs. In particular, the first
Since the thin wall portion 2 and the second thin wall portion 3 are attracted by the thick wall portion 6, the first thin wall portion 2 and the second thin wall portion 3 do not exist in a slight portion at both ends of the through hole 36.

There are two methods of manufacturing the nut with housing of the present invention. In the first manufacturing method, the housing and the core parallel to the mold opening direction are arranged in the mold, and the molded product with the housing is taken out. It is a method characterized by pulling out the core later. The second manufacturing method is to dispose the housing and the movable core in the mold, pull out the movable core before taking out the molded product with the housing, and then open the mold to take out the molded product. This is a characteristic method. The molding used in the first and second manufacturing methods includes injection molding, die casting, compression molding, transfer molding and the like.

The first method of manufacturing a nut with a housing will be described step by step with reference to FIG. Fig. 6 (a)
Is a basic structure of a mold device used in the first method of manufacturing a nut with a housing of the present invention, and FIG. 6 (b) shows a housing 14 to be inserted, respectively, in a portion common to the mold device shown in FIG. 2 use the same symbols as those in FIG. 2, and the description thereof is omitted in principle. The mold is manufactured in the first preparation step. Inside the first mold 20 and the second mold 21, a non-circular (eg elliptical) first support hole 26, a hole portion 56 corresponding to the outer shape of the nut 38 with a housing, and a second support hole 27 are continuous. Formed. The core 22, the first support hole 26, and the second support hole 27 arranged inside the first mold 20 and the second mold 21 are the core 22, the first support hole 26, and the core 22 used in the nut manufacturing method. It is similar to the second support hole 27. A housing 14 made of die-cast metal such as iron or aluminum is arranged on the inner surfaces of the first mold 20 and the second mold 21, and the first medium diameter hole 40, the large diameter hole 41 and the second medium diameter are provided in the housing 14. A through hole 36 composed of a hole 42 is formed adjacently on the same axis. The core 22 is inserted into the through hole 36 of the housing 14, and the first core support portion 24 and the second core support portion 25 of the core 22 are fitted and supported in the first support hole 26 and the second support hole 27. To be done. Holes 56 of the first mold 20 and the second mold 21, housing
A cavity 30 is formed by 14 and the core 22. The cavity 30 is configured by the space between the through hole 36 of the housing 14 and the screw portion 23, and the upper and lower surfaces / groove portion 47 of the housing 14 and the hole portion 56 of the first mold 20 and the second mold 21. .

According to the first step, the first die 20 and the second die
21 is opened, the housing 14 is inserted into the first mold 20 and the second mold 21, and the core 22 is provided with the screw part 23 on the outer peripheral part.
Is inserted into the through hole 36 of the housing 14, and the first core support portion 24 and the second core support portion 25 of the core 22 are fitted into the first support hole 26 and the second support hole 27, respectively. Next, the first mold 20 and the second mold 21 are closed. In the second step, the cavity is filled with the molten material to form the nut with housing. For example, a molten material of die-cast metal or synthetic resin injected from an injection molding machine is filled in the cavity 30 through a gate or the like,
The molten material is solidified to form the nut with housing. In the third step, when the solidification of the filled material reaches a predetermined level (when the solidification has progressed to a certain extent and the molded product with the housing is taken out, there is no fear of deformation of the molded product), the first mold 20 and the second mold 21 are opened, the core
First mold is a molded product with a housing 22 in the center.
And the second mold 21.

In the fourth step, when the solidification progresses further and there is no risk of deformation of the molded product even if the molded product with the housing is held and the core 22 is pulled out, the housing 14 is held with a vise. A spanner or the like having a non-circular (for example, elliptical) fitting hole is fitted to the first core support portion 24 or the second core support portion 25 of the core 22. While rotating the core 22 with a spanner or the like, the core 22 is removed from the molding in the through hole 36 of the housing 14.
If you pull out, the semi-finished product is completed. In this semi-finished product, a female screw having substantially the same shape as the threaded portion 23 is formed inside the molded product in the through hole 36, a nut having a substantially cylindrical thick portion and thin portions on both sides thereof, and a nut First on both sides
The ring-shaped portion 44 and the second ring-shaped portion 45 are continuously formed, and the first ring-shaped portion 44 and the second ring-shaped portion 45 are housed by the strip-shaped portion 46.
They are integrally connected via 14 upper parts.

In the fifth step (cooling step, including the third step and the fourth step in terms of time), the molded product with the housing of the semi-finished product undergoes molding shrinkage during cooling in the mold or after taking out. The amount of shrinkage in the thick part is larger than that in the thin part. Therefore, the thin portions on both sides of the thick portion are pulled in the axial direction due to the contraction of the thick portion, and the phase of the female screw of one thin portion is deviated from the phase of the female screw of the other thin portion.

In the sixth step, the female screw portion on the inner surface of the thick portion is partially or wholly cut to form a substantially annular cut portion 7, and the first female screw portion 4 and the second female screw portion 5 are formed. The screw shaft 11 to be screwed can be inserted into the cutout portion 7, and the nut 38 with housing (completed product) as shown in FIG. 5 is manufactured.
The reason for cutting the inner surface of the thick part and the extent of cutting are
This is similar to the case of the first nut manufacturing method.

The mold used in the second method of manufacturing the nut with housing is not shown in the drawing, but is shown in FIG. 6 (a), for example.
In the above, the screw part 23 is extended downward, a hole through which the screw part 23 passes is formed in the lower center part of the second mold 21, and the movable core can be pulled out while rotating. . The hole or other place in the lower central portion of the second mold 21 is a female screw with which the screw portion 23 can be screwed, and the screw portion 23 of the movable core is screwed with the female screw. The other structure is shown in FIG.
It is similar to that shown in (a).

The second method of manufacturing the nut with housing will be described separately for each step. It should be noted that the same parts as those in the first manufacturing method of the nut with housing will be denoted by the reference numerals in FIG. 6 (a), and the description thereof will be simplified or omitted. By the first step, the first mold 20 and the second mold 21 are opened, the movable core is inserted into the through hole 36 of the housing 14, and the housing 14 is inserted into the first mold 20 and the second mold 21. The first core supporting portion 24 and the second core supporting portion 25 of the movable core are inserted into the first supporting hole 26 and the second supporting hole 27, respectively. Next, the first mold 20 and the second mold 21 are closed. The shape of the cavity 30 is the same as that in the first manufacturing method of the nut with housing.

In the second step, the cavity is filled with the molten material to form the nut with housing. In the third step, the first mold 20 and the second mold 21 are held when solidification of the filled material has reached a predetermined level and there is no fear of deformation of the molded product with the housing even if the movable core is pulled out. Then, while rotating the movable core, the movable core is extracted from the molded product with the housing, the first mold 20 and the second mold 21. First
Inside the molded product with a housing left in the mold 20 and the second mold 21, female threads of substantially the same shape as the screw part 23 are formed, and a substantially cylindrical thick part and thin parts on both sides thereof are formed. A semi-finished product consisting of is completed. The structure of the molded product of the semi-finished product is the same as that of the first manufacturing method of the nut with housing.

In the fourth step, when the solidification of the molded product progresses further and the molded product with the housing is taken out and there is no fear of deformation of the molded product, the first mold 20 and the second mold 21 are removed. Open and remove the semi-finished molded product with the housing from the first mold 20 and the second mold 21. In the fifth step (cooling step. In terms of time, including the third step and the fourth step), the molded product with a semi-finished product housing undergoes molding shrinkage during cooling in the mold or after taking out, and the shrinkage occurs. The amount is larger in the thick part than in the thin part. Therefore, the thin portions on both sides of the thick portion are pulled in the axial direction due to the contraction of the thick portion, and the phase of the female screw of one thin portion is deviated from the phase of the female screw of the other thin portion.

In the sixth step, the female screw portion on the inner surface of the thick portion is partially or wholly cut to form a substantially annular cut portion 7, and the first female screw portion 4 and the second female screw portion 5 are formed. The screw shaft 11 to be screwed can be inserted into the cutout portion 7, and the nut 38 with housing (completed product) as shown in FIG. 5 is manufactured.

An example of using the nut with housing of the present invention will be described with reference to FIG. The motor bracket is connected adjacent to the base, the support side support unit 50 is connected to the left end of the base, and the fixed side support unit 51 is connected to the right end of the base. Screw shaft 11 by support side support unit 50 and fixed side support unit 51
Is rotatably supported, the drive motor is connected to the right end of the motor bracket, and the rotational force of the drive motor is transmitted to the screw shaft 11 via the coupling. Figure 5 on the screw shaft 11
A nut 38 with a housing having the structure shown in FIG. 4 is screwed, and the housing 14 is connected to the nut 38 with a housing by insert molding. Similar to the description in FIG. 4, since there is no axial clearance between the nut of the housing-equipped nut 38 and the screw shaft 11, the rotational momentum of the screw shaft 11 and the housing
Mutual conversion with the linear momentum of 14 is performed accurately. Then, the housing 14 is inserted into the nut 38 with the housing by insert molding, and the through hole 36 of the housing 14 is inserted.
Since the nut is formed by the threaded portion 23 of the core 22, the length between the upper surface of the housing 14 and the center of the first female threaded portion 4 and the second female threaded portion 5 of the nut 38 with the housing is made constant. be able to. Therefore, the length (height) H between the center line of the screw shaft 11 and the upper surface of the housing 14 can be made constant.

As shown in FIG. 7 (b), six mounting bolt holes 48 are formed on the upper surface of the housing 14, and a table or the like is fixed on the upper surface of the housing 14 so that an XY table shaft,
It can be used for a carrier machine, a screw tightener, a welding machine, a winding machine, a robot XYZ axis, various insertion devices, a work transfer device, a lift device, an automatic cutting machine, a robot handling device, an automatic assembly machine, and the like. In this case, since the height from the bottom surface of the base to the screw shaft 11 is constant and the height H is also constant, the height from the bottom surface of the base to the upper surface of the housing 14 is constant. The following are the characteristics of the nut with housing of the present invention when it is applied to the above applications. It is a table device that does not require the accuracy of using a ball screw, and reduces the axial clearance to some extent,
It is suitable for those that require the nut movement to correspond to the forward / reverse rotation of the screw shaft. Since the cost of the nut with housing is low, the cost of the entire device using the nut with housing can be reduced. Since the height of the table mounting surface is set to a predetermined height during molding, the table device can be completed simply by mounting the table guide device on the nut with housing in parallel with the screw shaft and attaching the table plate to the nut with housing. .

[0039]

According to the nut of the present invention, as described in claims 1 and 2, a first female screw portion and a second female screw portion are formed on the inner surfaces of the first thin portion and the second thin portion, respectively. There is a phase shift between the female screw portion and the second female screw portion, a cutout portion is formed on the inner surface of the thick portion, and the whole is integrally formed. Therefore, even though the nut structure is extremely simple, lightweight and inexpensive, it is possible to sufficiently exert the important function of reducing the clearance in the screw direction when the screw shaft is screwed.

The method of manufacturing a nut according to the present invention is defined by claims 3 to.
It is as described in 6 (a) to (f). That is, the female thread of the nut is formed by extracting the core while rotating it, and a phase shift is generated between the first female thread section and the second female thread section when the molten material of the die-cast metal or the synthetic resin cools down. It can be obtained by forming and shrinking the thick portion of the portion larger than the thin portions on both sides, and the cut portion is formed by partially or completely cutting the internal thread portion of the inner surface of the thick portion. As described above, in the molding process, the nut of the present invention can be manufactured in a short time by the extremely few steps of extracting the core while rotating it and cutting the inner surface of the thick portion. The nut manufactured by the manufacturing method of the present invention has uniform performance, and when the screw shaft is screwed, the axial clearance can be reduced, and the unit price of the nut can be considerably reduced by mass production.

According to a seventh aspect of the present invention, there is provided a nut with a housing, wherein the first nut is provided in the through hole of the housing.
The thin portion, the thick portion, and the second thin portion are fixed, and the first female screw portion and the second female screw portion are formed on the inner surfaces of the first thin portion and the second thin portion, respectively, and the first female screw portion and the second female screw portion are formed. There is a phase shift between and, a cut portion is formed on the inner surface of the thick portion, and the whole is integrally configured. Therefore, despite the fact that the nut with housing has a small number of parts, its structure is extremely simple, and it is lightweight and inexpensive, the important function of reducing the axial clearance when the screw shaft is screwed is sufficient. Can be demonstrated. Moreover, the nut with a housing of the present invention can be used to make a table feed device (straight guide device), and the table feed device can exhibit the following advantages. Since there is no axial clearance between the nut of the nut with housing and the screw shaft, mutual conversion between the rotational momentum of the screw shaft and the linear momentum of the housing is accurately performed. The housing is inserted into the nut with the housing by insert molding, and the nut is formed in the through hole of the housing by the threaded portion of the core. Therefore, the upper surface of the housing and the center of the first female screw portion and the second female screw portion of the nut with the housing The length between and can be constant.
Therefore, the length (height) H between the center line of the screw shaft and the upper surface of the housing can be made constant. A mounting bolt hole may be formed on the upper surface of the housing, and a table or the like may be fixed on the upper surface of the housing to provide various feeding devices. In this case, since the height from the bottom surface of the base to the screw shaft is constant and the height H is also constant, the height from the bottom surface of the base to the upper surface of the housing is constant. Since the cost of the nut with housing is low, the price of the table feeding device using the nut with housing can be reduced.

The method of manufacturing the nut with housing of the present invention is as described in claims 8 and 9 (a) to (f). That is, a nut is formed in the through hole of the housing by insert molding, and the female screw of the nut is formed by pulling out while rotating the core, and there is a phase shift between the first female screw part and the second female screw part. When the molten material of die-cast metal or synthetic resin cools, the thick part of the central part undergoes molding shrinkage larger than the thin parts on both sides, and the internal thread part of the inner part of the thick part is partially or entirely The excision portion is formed by excising it selectively. As described above, in the molding process, the housing of the present invention can be assembled in a short time without the trouble of assembling by the extremely small number of steps of inserting the housing, extracting the core while rotating it, and cutting off the inner surface of the thick portion. Capable nuts can be manufactured. The nut with housing manufactured by the manufacturing method of the present invention has uniform performance, and when the screw shaft is screwed, the axial clearance can be reduced,
The unit price of nuts with housing can be reduced considerably by mass production.

[Brief description of drawings]

1 (a) and 1 (b) are cross-sectional views of an embodiment of a nut of the present invention.

FIG. 2 is a cross-sectional view showing a mold device used in the first manufacturing method of the nut of the present invention.

FIG. 3 is a cross-sectional view showing a mold device used in a second method for manufacturing a nut according to the present invention.

FIG. 4 is a cross-sectional view showing a state in which an embodiment of the nut of the present invention and a screw shaft are screwed together.

FIG. 5 is a sectional view of an embodiment of the nut with housing of the present invention.

FIG. 6 (a) is a cross-sectional view showing a mold device used in the first method of manufacturing a nut with a housing of the present invention,
FIG. 6B is an enlarged perspective view of the insert (housing).

7 (a) and 7 (b) are views showing an example of using the nut with housing of the present invention.

8 (a) and 8 (b) are views showing a conventional nut with a housing.

[Explanation of symbols]

 1 Nut 2 1st thin part 3 2nd thin part 4 1st female screw part 5 2nd female screw part 6 thick part 7 cutout part 14 housing 40 1st medium diameter hole 41 large diameter hole 42 2nd medium diameter hole

Claims (9)

[Claims] 1. A substantially cylindrical first thin portion, thick portion, and second portion.
The thin portions are integrally formed adjacent to each other, and the first female screw portion and the second female screw portion are respectively formed on the inner surfaces of the first thin portion and the second thin portion, and the first female screw portion and the second female screw portion are the same. Are located on the same axis with a screw, and there is a phase shift between the first female screw portion and the second female screw portion, and a cut portion is formed on the inner surface of the thick portion, and the first female screw portion and the second female screw portion are formed. A nut capable of inserting a screw shaft that is screwed into the female screw portion into the cutout portion. 2. A nut having a thick wall portion at a substantially central portion is made thicker than a first thin wall portion and a second thin wall portion on both sides of the nut, and the first and second female screw portions are formed by contraction after molding. 2. The nut according to claim 1, wherein the phases are out of phase, a part or all of the threaded portion on the inner surface of the central thick portion is cut off, and the axial clearance is reduced when the screw shaft is screwed. 3. A substantially cylindrical first thin portion, thick portion and second portion.
The thin portions are integrally formed adjacent to each other, and the first female screw portion and the second female screw portion are respectively formed on the inner surfaces of the first thin portion and the second thin portion, and the first female screw portion and the second female screw portion are the same. Are located on the same axis with a screw, and there is a phase shift between the first female screw portion and the second female screw portion, and a cut portion is formed on the inner surface of the thick portion, and the first female screw portion and the second female screw portion are formed. In a method of manufacturing a nut in which a screw shaft screwed with an internal thread portion is insertable into the cutout portion, (a) a mold is opened, and a core having a threaded portion formed on the outer periphery is provided in the mold. Then, the first step of closing the mold, (b) the second step of filling and molding the molten material of die casting metal or synthetic resin into the cavity of the mold, (c) opening the mold, the core is in the center The third step of removing the molded product from the mold from the mold, (d) Holding the molded product and removing it from the molded product while rotating the core. 4 steps, (e) By cooling the molded product, the thick part in the center part shrinks more greatly than the thin parts on both sides, and the phase of the internal thread of one thin part is different from the phase of the internal thread of the other thin part. Fifth step of shifting, (f) A method of manufacturing a nut comprising a sixth step of partially or completely cutting off the female screw portion on the inner surface of the thick portion. 4. A substantially cylindrical first thin-walled portion, thick-walled portion and second
The thin portions are integrally formed adjacent to each other, and the first female screw portion and the second female screw portion are respectively formed on the inner surfaces of the first thin portion and the second thin portion, and the first female screw portion and the second female screw portion are the same. Are located on the same axis with a screw, and there is a phase shift between the first female screw portion and the second female screw portion, and a cut portion is formed on the inner surface of the thick portion, and the first female screw portion and the second female screw portion are formed. A method of manufacturing a nut, wherein a screw shaft screwed into an internal thread portion can be inserted into the cutout portion, (a) first step of closing a mold, (b)
Second step of filling and molding a die-cast metal or synthetic resin molten material into the cavity of the mold, (c) Third step of extracting the movable core from the mold and the molded product while rotating the movable core.
Step (d) Open the mold and take out the molded product from the mold Fourth
Process, (e) Cooling of the molded product causes the thick part in the center to shrink more than the thin parts on both sides, and the phase of the female screw of one thin part shifts the phase of the female screw of the other thin part Fifth step, (f) A method of manufacturing a nut, which comprises the sixth step of partially or completely cutting off the female screw portion on the inner surface of the thick portion. 5. A substantially cylindrical first thin portion, thick portion and second portion.
The thin portions are integrally formed adjacent to each other, and the first female screw portion and the second female screw portion are respectively formed on the inner surfaces of the first thin portion and the second thin portion, and the first female screw portion and the second female screw portion are the same. Are located on the same axis with a screw, and there is a phase shift between the first female screw portion and the second female screw portion, and a cut portion is formed on the inner surface of the thick portion, and the first female screw portion and the second female screw portion are formed. A threaded shaft screwed into the female threaded portion can be inserted into the cutout portion, and the thickened portion at the approximate center of the nut is made thicker than the first thinned portion and the second thinned portion on both sides thereof, and after molding The phase of the first female threaded portion and the second female threaded portion is shifted due to the contraction of, and part or all of the threaded portion on the inner surface of the central thick portion is cut off, and when the screw shaft is screwed, the axial clearance is reduced. (A) Open the mold and insert the core with the threaded part 1st step of arranging in the mold and then closing the mold, (b) 2nd step of filling and molding the molten material of die casting metal or synthetic resin into the cavity of the mold, (c) opening the mold , The third step of removing the molded product with the core in the center from the mold, (d) the fourth process of holding the molded product and removing it from the molded product while rotating the core, (e) by cooling the molded product The fifth step, in which the thick part of the central part undergoes molding shrinkage to a greater extent than the thin parts on both sides, and the phase of the female screw of the other thin part deviates from the phase of the female screw of the other thin part, (f) thick part A method for manufacturing a nut, which comprises the sixth step of partially or completely cutting off the female screw portion on the inner surface of the. 6. A substantially cylindrical first thin-walled portion, thick-walled portion and second
The thin portions are integrally formed adjacent to each other, and the first female screw portion and the second female screw portion are respectively formed on the inner surfaces of the first thin portion and the second thin portion, and the first female screw portion and the second female screw portion are the same. Are located on the same axis with a screw, and there is a phase shift between the first female screw portion and the second female screw portion, and a cut portion is formed on the inner surface of the thick portion, and the first female screw portion and the second female screw portion are formed. A threaded shaft screwed into the female threaded portion can be inserted into the cutout portion, and the thickened portion at the approximate center of the nut is made thicker than the first thinned portion and the second thinned portion on both sides thereof, and after molding The phase of the first female threaded portion and the second female threaded portion is shifted due to the contraction of, and part or all of the threaded portion on the inner surface of the central thick portion is cut off, and when the screw shaft is screwed, the axial clearance is reduced. In the method for manufacturing a nut, the first step of closing the die, (b)
Second step of filling and molding a die-cast metal or synthetic resin molten material into the cavity of the mold, (c) Third step of extracting the movable core from the mold and the molded product while rotating the movable core.
Process, (d) Open the mold and take out the molded product from the mold 4th
Process, (e) Cooling of the molded product causes the thick part in the center to shrink more than the thin parts on both sides, and the phase of the female screw of one thin part shifts the phase of the female screw of the other thin part Fifth step, (f) A method of manufacturing a nut, which comprises the sixth step of partially or completely cutting off the female screw portion on the inner surface of the thick portion. 7. A through hole formed of a first medium diameter hole, a large diameter hole, and a second medium diameter hole is formed in the housing, and the first medium diameter hole, the large diameter hole, and the second medium diameter hole each have a first hole. The thin portion, the thick portion, and the second thin portion are integrally fixed so as to be adjacent to each other, and the thick portion at substantially the center of the nut is made thicker than the first thin portion and the second thin portion on both sides thereof, and Due to contraction after molding, the first female screw portion of the first thin portion and the second female screw portion of the second thin portion are out of phase, and part or all of the screw portion on the inner surface of the central thick portion is cut off, A nut with a housing that reduces the axial clearance when the shaft is screwed. 8. A through hole including a first medium diameter hole, a large diameter hole, and a second medium diameter hole is formed in the housing, and the first medium diameter hole, the large diameter hole, and the second medium diameter hole each have a first hole. The thin portion, the thick portion, and the second thin portion are integrally fixed so as to be adjacent to each other, and the thick portion at substantially the center of the nut is made thicker than the first thin portion and the second thin portion on both sides thereof, and Due to contraction after molding, the first female screw portion of the first thin portion and the second female screw portion of the second thin portion are out of phase, and part or all of the screw portion on the inner surface of the central thick portion is cut off, In the method of manufacturing a nut with a housing that has a reduced axial clearance when the shaft is screwed, (a) open the mold, insert the housing into the mold, and insert the core with the threaded portion on the outer periphery into the housing. 1st step of inserting the through hole of the above into the mold and then closing the mold, (b) die casting metal Is the second step of filling and molding the molten material of synthetic resin into the cavity of the mold, (c) The third step of opening the mold and taking out the molded product with the housing with the core in the center from the mold, (d) The fourth step of holding the housing and extracting the molded product from the housing while rotating the core, (e) By cooling the molded product with the housing,
The 5th step (f) of the thick part where the thick part of the central part undergoes molding shrinkage more than the thin parts on both sides and the phase of the female screw of one thin part deviates from the phase of the female screw of the other thin part A method of manufacturing a nut with a housing, comprising the sixth step of partially or completely cutting off the internal thread portion of the inner surface. 9. A through hole including a first medium diameter hole, a large diameter hole, and a second medium diameter hole is formed in the housing, and the first medium diameter hole, the large diameter hole, and the second medium diameter hole each have a first hole. The thin portion, the thick portion, and the second thin portion are integrally fixed so as to be adjacent to each other, and the thick portion at substantially the center of the nut is made thicker than the first thin portion and the second thin portion on both sides thereof, and Due to contraction after molding, the first female screw portion of the first thin portion and the second female screw portion of the second thin portion are out of phase, and part or all of the screw portion on the inner surface of the central thick portion is cut off, In the method of manufacturing a nut with a housing that has a reduced axial clearance when the shaft is screwed, (a) open the mold, insert the movable core into the through hole of the housing, and insert the housing into the mold. First step of disposing a movable core having a threaded portion on the outer periphery in a mold and then closing the mold (b) The second step of filling and molding the molten material of die casting metal or synthetic resin into the cavity of the mold, (c) extracting the movable core from the molded product with the housing and the mold while rotating the movable core. The third step,
(d) Fourth step of opening the mold and taking out the molded product with housing from the mold, (e) Cooling of the molded product with housing causes the thick part in the center to shrink more than the thin parts on both sides. Then, the fifth step in which the phase of the internal thread of one thin part is out of phase with the phase of the internal thread of the other thin part, (f) The sixth step of partially or wholly cutting the internal thread part of the inner surface of the thick part Manufacturing method of nut with housing.