JP2008286358A - Manufacturing method of rotation/linear motion converting mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of appropriately assembling a rotation/linear motion converting mechanism which provides high lead setting accuracy. <P>SOLUTION: The rotation/linear motion converting mechanism comprises a ring shaft having a ring shaft body 21 and a rear ring gear 24, a sun shaft having a sun shaft body 31 and a rear sun gear 34, and a planetary shaft having a planetary shaft body 41 and a rear planetary gear 44. A third assembly 53 formed of the respective shaft bodies 21, 31, 41 is assembled. The rear sun gear 34 is mounted on an assembly tool 6 so as not to rotate, and the rear ring gear 24 and the rear planetary gear 44 are mounted so as to mesh with the rear sun gear 34. The rear ring gear 24, the rear sun gear 34, and the rear planetary gear 44 are moved together with the assembly tool 6 by inserting an insertion part 62 in a surround part of the third assembly 53 to assemble on the third assembly 53. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a rotational linear motion conversion mechanism that converts rotational motion into linear motion.

As a rotation linear motion conversion mechanism, for example, one described in Patent Document 1 is known.
This rotational linear motion conversion mechanism is configured by a combination of an annular shaft having a space extending in the axial direction therein, a solar shaft disposed inside the annular shaft, and a plurality of planetary shafts disposed around the solar shaft. Has been. Further, the female screw of the annular shaft, the male screw of the sun shaft, and the male screw of the planetary shaft are engaged with each other. In the rotational linear motion conversion mechanism having such a structure, when the annular shaft is rotated, the solar shaft linearly moves by the planetary shaft moving around the solar axis through the force transmitted from the annular shaft. It becomes like this. That is, it is possible to convert the rotational motion of the annular shaft into the linear motion of the solar shaft.
JP-A-10-196757

  By the way, the lead of the rotational linear motion conversion mechanism (the stroke amount of the solar axis per one rotation of the annular shaft) is determined by the number of threads of each screw provided on the annular shaft, the solar axis, and the planetary shaft, It is determined by the reduction ratio of the motion conversion mechanism.

  The reduction ratio is determined by the effective diameter ratio of each screw. The effective diameter of each screw varies due to the processing accuracy of the screw, or changes due to wear on the contact surface between the screws to be screwed. To do. Therefore, it is difficult to obtain a stable and constant reduction ratio in the rotational linear motion conversion mechanism.

  The rotational linear motion conversion mechanism is a structure in which the positional relationship between the rotation center of the annular shaft, the rotation center of the sun shaft, and the revolution center of the planetary shaft is determined by the engagement of each screw. It can be said that the center of revolution of the planetary shaft is easily displaced from the center of rotation of the annular shaft. And if the center of rotation of the sun axis or the center of revolution of the planetary axis deviates from the center of rotation of the annular axis, the position of the contact surface of each screw changes accordingly, and the effective diameter of each screw also changes. In this case, it is difficult to obtain a stable and constant reduction ratio.

  In such a rotational linear motion conversion mechanism that cannot obtain a stable and constant reduction ratio, it is difficult to secure a lead as designed, and this leads to an unnecessary reduction in the setting accuracy of the lead.

  Therefore, in order to obtain a stable and constant reduction ratio, the center of rotation of the annular shaft is separate from the screw mechanism for linearly moving the solar shaft (the female screw of the annular shaft, the male screw of the solar shaft, the male screw of the planetary shaft). It is conceivable to provide a guide mechanism for guiding the relative movement of the annular axis, the sun axis and the planetary axis in a state where the rotation center of the sun axis and the revolution center of the planetary axis coincide with each other.

  In such a rotational linear motion conversion mechanism, high lead setting accuracy can be obtained without depending on the effective diameter of each screw. However, even in the case of the rotational linear motion conversion mechanism, if the guide mechanism is not correctly assembled, a desired reduction ratio cannot be obtained, and the lead setting accuracy is also lowered.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a manufacturing method capable of properly assembling a rotational linear motion conversion mechanism having a structure capable of obtaining high lead setting accuracy.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 is an annular shaft in which a space is provided, a solar shaft disposed in the annular shaft, and a plurality of shafts disposed around the solar shaft in the annular shaft. A planetary shaft, a female screw provided on the annular shaft as a circular screw, a gear provided on the annular shaft as a circular gear, a male screw provided on the solar shaft as a solar screw, When the gear provided on the shaft is a sun gear, the male screw provided on the planetary shaft is a planetary screw, and the gear provided on the planetary shaft is a planetary gear, the annular screw, the sun screw and the planetary screw mesh with each other. The annular gear, the sun gear and the planetary gear mesh with each other, and the planetary shaft through the planetary motion associated with the rotational motion of one of the annular shaft and the sun shaft. The other of the axis and the sun axis Satisfying the condition that movement is obtained, and the annular shaft includes an annular shaft body provided with the annular screw and an annular gear portion formed with the annular gear, The sun shaft includes a sun shaft main body provided with the sun screw and a sun gear portion formed with the sun gear, and the planetary shaft is formed by the planet shaft main body provided with the planet screw and the planet gear. A rotating linear motion conversion mechanism comprising a planetary gear portion formed, and a manufacturing method for manufacturing the rotating linear motion conversion mechanism, the assembly comprising a combination of the sun shaft, the annular shaft main body, and the planetary shaft main body Assembling the coaxial assembly as a shaft assembly, and a set having a plurality of insertion portions that can be inserted into a portion surrounded by the sun shaft, the planetary shaft, and the annular shaft inside the shaft assembly. The sun tooth is attached to the attachment jig. A gear mounting step of mounting the portion in a non-rotatable state through engagement with the assembly jig, and moving the sun gear portion together with the assembly jig through insertion of the insertion portion into the enclosed portion. And assembling the planetary gear part to the planetary shaft body while meshing the sun gear, the planetary gear, and the annular gear, The gist is to include a second assembling step of assembling the annular gear portion to the annular shaft main body.

  In the rotational linear motion conversion mechanism, the reduction ratio is determined by the meshing of the annular gear, the sun gear, and the planetary gear. For this reason, the reduction ratio of the rotary linear motion conversion mechanism is kept constant in a stable state without being affected by the effective diameters of the annular screw, solar screw, and planetary screw, and the setting of the lead of the rotary linear motion conversion mechanism is set. High accuracy is also maintained.

  And according to the said manufacturing method, in manufacture of such a rotation linear motion conversion mechanism, by inserting the insertion part of an assembly jig in the said enclosed part (enclosure part) inside a shaft assembly, an annular shaft main body The attitude of the solar axis main body and each planetary axis main body is a reference attitude (the central axis of each planetary axis main body is parallel to the central axis of the annular axis main body or the solar axis main body, To a position in which the rotation center of the solar shaft body, the rotation center of the sun shaft body and the revolution center of each planetary shaft body coincide with each other). Then, the sun gear part is assembled to the sun shaft body in a state where relative rotation is restricted, and further, the planetary gear part is assembled to the planetary shaft body and the ring gear part is attached to the ring shaft body. Assembling can be performed with the gears engaged. Therefore, it is possible to properly assemble the guide mechanism including the sun gear, the planetary gear, and the annular gear, and thus to properly assemble the rotating linear motion conversion mechanism.

  According to a second aspect of the present invention, in the method for manufacturing the rotational linear motion conversion mechanism according to the first aspect, the gear mounting step is performed while meshing the sun gear, the planetary gear, and the annular gear. A step of attaching to a jig, wherein the first and second assembling steps are moved together with the assembling jig to move the sun gear part to the sun shaft body and the planetary gear part to the planetary shaft. The gist of the present invention is the step of assembling the annular gear portion to the main body and the annular shaft main body.

  According to the above manufacturing method, the annular gear part, the sun gear part, and the planetary gear part can be assembled through one step of inserting the insertion part of the assembly jig into the surrounding part inside the shaft assembly. it can.

  According to a third aspect of the present invention, in the method for manufacturing the rotational linear motion conversion mechanism according to the first or second aspect, the sun gear portion is formed in an annular shape and is formed in the sun shaft main body. A jig that is press-fitted and fixed to the cylindrical assembly part and attaches a cylindrical press-fitting jig whose diameter is reduced toward the tip prior to the first assembly step. The gist further includes an attaching step, and the first assembling step includes inserting the press-fitting jig into the sun gear portion.

  When the sun gear part is press-fitted and fixed to the sun shaft body, the rotation torque is adjusted so that the sun gear part and the sun shaft body do not rotate relative to each other when the rotation torque is input to the sun shaft body or the sun gear part. It is necessary to fix the sun gear portion and the sun shaft main body with sufficient strength.

  The strength limit for rotational torque is the press-fitting allowance (specifically, the difference between the diameter of the inner peripheral surface of the sun gear portion and the outer peripheral surface of the assembly portion) required for press-fitting the sun gear portion into the sun shaft body. It can be increased by increasing the size. However, when the press-fitting allowance becomes excessively large, the sun gear portion is unnecessarily deformed, leading to a decrease in lead setting accuracy of the rotary linear motion conversion mechanism.

  On the other hand, the press-fitting length (specifically, the length in the center line direction at the contact portion between the inner peripheral surface of the sun gear portion and the outer peripheral surface of the assembly portion) required for press-fitting the sun gear portion into the sun shaft main body is determined. The intensity limit can also be increased by increasing the length. However, when the space where the sun gear portion can be arranged is small, the press-fitting length cannot be made sufficiently long.

  Normally, when an annular member is press-fitted and fixed to a cylindrical member, the end of each member is formed in a so-called tapered shape so as to guide the press-fitting. This taper shape is one factor that limits the press-fitting length.

  In this respect, according to the above manufacturing method, the press-fitting jig can guide the press-fitting of the sun gear portion into the sun shaft main body, so the end portion of the inner peripheral surface of the sun gear portion and the outer peripheral surface of the sun shaft main body It is not necessary to form the end portion (specifically, the tip of the assembly portion) in a tapered shape. Therefore, the press-fitting allowance can be lengthened by that amount, and the strength limit can be increased.

  According to a fourth aspect of the present invention, in the manufacturing method of the rotational linear motion converting mechanism according to the third aspect, a cutting blade having a shape protruding outward is formed on the outer peripheral surface as the press-fitting jig. The gist is to use the thing.

  According to the above manufacturing method, when the press-fitting jig passes through the inside of the sun gear portion, a groove can be formed on the inner peripheral surface of the sun gear portion by the cutting blade, whereby the inner peripheral surface of the sun gear portion. The coefficient of friction can be increased to increase the strength limit.

  Invention of Claim 5 is a process of inserting the said press-fitting jig | tool into the said assembly jig in the said 1st assembly process in the manufacturing method of the rotation linear motion conversion mechanism of Claim 4. The gist of the present invention is to use an assembly jig in which a groove extending in the direction of the center line of the press-fitting jig is formed on the inner surface of the portion into which the press-fitting jig is inserted.

  According to the above manufacturing method, when the sun gear part is assembled at the correct position, when the press fitting jig passes through the inside of the assembling jig, the cutting blade of the press fitting jig has the structure of the assembling jig. If the sun gear part rotates around the center line with respect to the press-fitting jig and the assembly position may shift due to some reason, the press-fitting jig The cutting blade can be configured to abut against the assembly jig. Therefore, the sun gear part can be assembled while confirming that it is assembled at the correct position, and the guide mechanism can be assembled properly.

  According to a sixth aspect of the present invention, in the method for manufacturing a rotational linear motion conversion mechanism according to the fourth or fifth aspect, the press-fitting jig includes a distal end portion having a large outer peripheral surface gradient and a proximal end portion having a smaller gradient surface. The gist of the present invention is that the cutting edge is formed on the base end portion.

  When the protrusion is formed in a cylindrical shape that is reduced in diameter toward the tip, the protrusion is formed in the portion where the gradient is smaller than the portion where the gradient on the outer peripheral surface is large for the convenience of processing. Is easy. In this regard, according to the above manufacturing method, since the cutting edge can be formed in a portion having a small gradient, the press-fitting jig having the cutting edge can be formed relatively easily. Moreover, when the sun gear portion is press-fitted into the sun shaft main body, the sun gear portion can be accurately guided to the sun shaft main body by the tip portion having a large gradient.

  Invention of Claim 7 is a manufacturing method of the rotation linear motion conversion mechanism as described in any one of Claims 4-6. WHEREIN: In the said jig | tool attachment process, the said press-fit jig | tool is the said solar shaft main body. The gist is that it is attached to the assembling part in a non-rotatable state through engagement with the assembling part.

A method of manufacturing a rotating linear motion conversion mechanism.
When the groove is formed on the inner peripheral surface of the sun gear portion by the cutting blade of the press fitting jig, when the groove that extends in a spiral shape is formed by rotating the press fitting jig around the center line of the sun shaft body, When the sun gear portion is press-fitted into the sun shaft main body, there is a possibility that a force for rotating the sun gear portion around the center line by the groove acts. This is not preferable because it causes a deviation in the assembly position of the sun gear portion.

  According to the above manufacturing method, the press-fitting jig can be structured not to rotate around the center line of the sun shaft body, and a groove extending in the center line direction of the sun shaft body is formed on the inner peripheral surface of the sun gear portion. Therefore, it is possible to accurately suppress the displacement of the assembly position of the sun gear portion.

  The invention according to claim 8 is the manufacturing method of the rotational linear motion conversion mechanism according to any one of claims 1 to 7, wherein the rotational linear motion conversion mechanism is a first annular gear as the annular gear. And the second annular gear is provided, the first annular gear is provided at one end of the annular shaft, and the second annular gear is provided at the other end, A first annular gear is provided on the annular shaft main body, the second annular gear is formed on the annular gear portion, and a first sun gear and a second sun gear are used as the sun gear. A first planetary gear as a planetary gear, and a first planetary gear as the planetary gear, the first sun gear being provided in the sun shaft main body and the second sun gear being formed in the sun gear portion. A gear and a second planetary gear are provided; The first planetary gear is provided at one end of the planetary shaft, the second planetary gear is provided at the other end, and the first planetary gear is provided at the planetary shaft main body and the first planetary gear. Two planetary gears are formed in the planetary gear portion, the first annular gear and the first sun gear are meshed with the first planetary gear, the second annular gear and the first The gist of the present invention is to satisfy the condition that the two sun gears and the second planetary gears are engaged with each other.

  According to the manufacturing method described above, it is possible to appropriately assemble a rotary linear motion conversion mechanism including two sets of guide mechanisms configured by an annular gear, a sun gear, and a planetary gear.

  An embodiment embodying a method for manufacturing a rotating linear motion conversion mechanism according to the present invention will be described. Below, it demonstrates in order of the structure of the rotation linear motion conversion mechanism assembled through the manufacturing method of this embodiment, the operation | movement aspect of the conversion mechanism, and the manufacturing method of the conversion mechanism.

<Structure of rotating linear motion conversion mechanism>
With reference to FIG.1 and FIG.2, the structure of the rotation linear motion conversion mechanism 1 is demonstrated.
As shown in FIGS. 1 and 2, the rotary linear motion conversion mechanism 1 includes a ring shaft 2 having a space therein, a sun shaft 3 disposed inside the ring shaft 2, and a sun shaft 3 in the ring shaft 2. It is configured by a combination with a plurality of planetary shafts 4 arranged around the shaft 3. A front collar 11 and a rear collar 12 are provided as elements for supporting the sun shaft 3. The planetary shafts 4 are arranged at equal intervals around the sun shaft 3. In the present embodiment, the rotational linear motion conversion mechanism 1 having a structure including nine planetary shafts 4 is assumed. However, the number of planetary shafts 4 can be changed as appropriate.

  In the rotational linear motion conversion mechanism 1, one of the components of the ring shaft 2 and each planetary shaft 4 is engaged by meshing between the screws and gears provided on the ring shaft 2 and the screws and gears provided on each planetary shaft 4. Force is transmitted to the other component. Further, due to the engagement of the screw and gear provided on the sun shaft 3 and the screw and gear provided on each planetary shaft 4, a force is applied from one component of the sun shaft 3 and each planetary shaft 4 to the other component. Communicated.

  The rotating linear motion conversion mechanism 1 operates as follows based on the combination of these components. That is, when one component of the ring shaft 2 and the sun shaft 3 rotates, each planetary shaft 4 performs a planetary motion around the sun shaft 3 through the force transmitted from the component. Thereby, the component moves in the axial direction with respect to each planetary shaft 4 through the force transmitted from each planetary shaft 4 to the other component of the ring shaft 2 and the sun shaft 3.

  Thus, the rotational linear motion conversion mechanism 1 is configured as a motion conversion mechanism that converts one rotational motion of the ring shaft 2 and the sun shaft 3 into the other linear motion of the ring shaft 2 and the sun shaft 3. In the present embodiment, with respect to the axial direction of the sun shaft 3, the direction in which the sun shaft 3 is pushed out from the ring shaft 2 is the front direction FR, and the direction in which the sun shaft 3 is pulled into the ring shaft 2 is the back direction RR. Yes. Further, when an arbitrary position of the rotational linear motion conversion mechanism 1 is used as a reference, a range on the front direction FR side from the reference position is a front side, and a range on the back direction RR side from the reference position is a back side. Yes.

  The front collar 11 is configured as an element having a plain bearing 11A for supporting the sun shaft 3 and an O-ring 11B for sealing the opening on the front side of the ring shaft 2. The front collar 11 is fixed to an opening on the front side of the ring shaft 2. The back collar 12 is configured as an element having a plain bearing 12 </ b> A for supporting the sun shaft 3 and an O-ring 12 </ b> B for sealing the opening on the back side of the ring shaft 2. The back collar 12 is fixed to the opening on the back side of the ring shaft 2. The front collar 11 is provided with a plurality of oil holes 11H for supplying lubricating oil to the inside of the ring shaft 2 (where the screws and gears of the ring shaft 2, the sun shaft 3 and each planetary shaft 4 are meshed). ing.

  When the force which inclines the centerline of the sunshaft 3 with respect to the centerline of the ring shaft 2 and each planetary shaft 4 is applied to the sunshaft 3 in each of the slide bearings 11A and 12A, the screw of the sunshaft 3 is caused by this force. In addition, it is provided as an element for regulating the inclination of the sun shaft 3 before the gear and the screw and gear of each planetary shaft 4 interfere with each other. That is, when the tilting force is applied to the sun shaft 3, the sun shaft 3 and the slide bearings 11A and 12A come into contact with each other before the screws and gears of the sun shaft 3 interfere with the screws and gears of the planetary shafts 4. Thus, the transmission of such force to the inside of the rotary linear motion conversion mechanism 1 is suppressed.

  In the rotary linear motion conversion mechanism 1, the sun shaft 3 is supported through the front collar 11 and the rear collar 12 as described above, while each planetary shaft 4 is supported by both the front collar 11 and the rear collar 12. Not. That is, the radial position of the sun shaft 3 is constrained by the engagement of the screw and gear and the front collar 11 and the rear collar 12, while the radial position of each planetary shaft 4 is only by the engagement of the screw and gear. It is restrained.

[1] “About the structure of the ring shaft”
The structure of the ring shaft 2 will be described with reference to FIGS. 3 and 4. 3A shows the planar structure of the ring shaft 2, and FIG. 3B shows the side structure of the ring shaft 2. 4A shows a cross-sectional structure of the ring shaft 2 along the center line, and FIG. 4B shows a cross-sectional structure in a state where a part of the ring shaft 2 is disassembled.

  As shown in FIGS. 3 and 4, the ring shaft 2 is configured as an element in which an internal thread (ring screw 22), a front ring gear 23, and a rear ring gear 24 are provided on a ring shaft main body 21 that is a main body thereof. Yes. Further, spur gears having the same shape are provided as the front ring gear 23 and the rear ring gear 24. That is, the specifications (reference pitch circle diameter, number of teeth, etc.) of the front ring gear 23 and the rear ring gear 24 are set to be equal to each other.

  The ring shaft main body 21 includes a main body screw portion 21A in which an annular screw 22 is formed, a main body gear portion 21B in which a front ring gear 23 is assembled, and a main body gear portion 21C in which a rear ring gear 24 is assembled. It is configured. A flange 25 is formed on the outer peripheral surface of the ring shaft main body 21 so as to protrude over the entire circumference in the circumferential direction.

  The front ring gear 23 is formed separately from the ring shaft main body 21, and is assembled to the end portion on the front side of the ring shaft main body 21. Further, the front ring gear 23 is configured such that its center line is aligned with the center line of the ring shaft body 21 when assembled to the ring shaft body 21. In the present embodiment, the front ring gear 23 is fixed to the ring shaft main body 21 by press-fitting as to how the front ring gear 23 is assembled to the ring shaft main body 21.

  The rear ring gear 24 is formed separately from the ring shaft main body 21 and is assembled to the end portion on the rear side of the ring shaft main body 21. Further, the rear ring gear 24 is configured such that its center line is aligned with the center line of the ring shaft body 21 when assembled to the ring shaft body 21. In the present embodiment, the back ring gear 24 is fixed to the ring shaft main body 21 by press-fitting as to how the back ring gear 24 is assembled to the ring shaft main body 21.

[2] “Sunshaft structure”
The structure of the sun shaft 3 will be described with reference to FIG. 5A shows a planar structure of the sun shaft 3, and FIG. 5B shows a planar structure in which a part of the sun shaft 3 is disassembled.

  As shown in FIG. 5, the sun shaft 3 is configured as an element in which a male shaft (sun screw 32), a front sun gear 33, and a rear sun gear 34 are provided on a sun shaft main body 31. As the front sun gear 33 and the back sun gear 34, a spur toothed external gear having the same shape is provided at a position sandwiching the sun screw 32 therebetween. The specifications (reference pitch circle diameter, number of teeth, etc.) of the front sun gear 33 and the back sun gear 34 are set to be equal to each other.

  The sun shaft 3 is configured by a combination of a sun shaft main body 31 and a rear sun gear 34. In the present embodiment, the back sun gear 34 is fixed to the sun shaft main body 31 by press-fitting as to how the back sun gear 34 is assembled to the sun shaft main body 31. The rear sun gear 34 can be fixed to the sun shaft main body 31 by a method other than press fitting. In the sun shaft 3, the center line (axis line) of the sun shaft main body 31 corresponds to the center line of the sun shaft 3.

  The sun shaft main body 31 includes a main body screw portion 31A in which a sun screw 32 is formed on the outer peripheral surface, a main body gear portion 31B in which a front sun gear 33 is formed, and a main body gear portion 31C in which the rear sun gear 34 is assembled. It is configured. A recess 35 is formed on the outer peripheral surface of the main body gear portion 31C at the end on the side where the rear sun gear 34 starts to be fitted when the rear sun gear 34 is assembled.

  The rear sun gear 34 is formed separately from the sun shaft main body 31. The rear sun gear 34 is configured such that its center line is aligned with the center line of the sun shaft body 31 when assembled to the sun shaft body 31.

[3] “Planetary shaft structure”
The structure of the planetary shaft 4 will be described with reference to FIG. 6A shows a planar structure of the planetary shaft 4, and FIG. 6B shows a sectional structure of the planetary shaft 4 along the center line.

  As shown in FIG. 6, the planetary shaft 4 is configured as an element in which a planetary shaft main body 41 as a main body is provided with a male screw (planetary screw 42), a front planetary gear 43, and a rear planetary gear 44. As the front planetary gear 43 and the back planetary gear 44, spur gears having the same shape are provided. That is, the specifications (reference pitch circle diameter, number of teeth, etc.) of the front planetary gear 43 and the back planetary gear 44 are set to be equal to each other.

  The planetary shaft main body 41 includes a main body screw portion 41A having a planetary screw 42 formed on the outer peripheral surface, a main body gear portion 41B having a front planetary gear 43 formed thereon, and a main body gear portion 41C to which the rear planetary gear 44 is assembled. It is configured to include.

The front planetary gear 43 is formed integrally with the front end portion of the planetary shaft main body 41.
The rear planetary gear 44 is formed separately from the planetary shaft main body 41, and is provided at an end portion on the rear side of the planetary shaft main body 41. Specifically, the rear planetary gear 44 is assembled to the planetary shaft main body 41 by inserting the main body gear portion 41C of the planetary shaft main body 41 into the bearing hole 44H. The back planetary gear 44 is assembled to the planetary shaft main body 41 in a state where one end surface is in contact with the planetary shaft main body 41. Further, the back planetary gear 44 is configured such that its center line is aligned with the center line of the planetary shaft body 41 in a state where it is assembled to the planetary shaft body 41. With respect to the manner of assembling the back planetary gear 44 with respect to the planetary shaft main body 41, in this embodiment, a clearance fit is adopted so that the back planetary gear 44 can rotate with respect to the planetary shaft main body 41. In addition, as an assembling mode for obtaining relative rotation between the planetary shaft main body 41 and the rear planetary gear 44, an assembling mode other than clearance fit can be employed.

[4] “Relationship between components”
With reference to FIGS. 7-10, the relationship of each component in the rotation linear motion conversion mechanism 1 is demonstrated. FIG. 7 shows a cross-sectional structure of the rotary linear motion conversion mechanism 1 along the center line of the sun shaft 3. 8 shows a sectional structure of the rotational linear motion conversion mechanism 1 along the DA-DA line in FIG. 7, FIG. 9 shows a sectional structure of the rotational linear motion conversion mechanism 1 along the DB-DB line in FIG. These respectively show the cross-sectional structures of the rotary linear motion conversion mechanism 1 along the DC-DC line of FIG.

As shown in FIGS. 7 to 10, in the rotary linear motion conversion mechanism 1, the operation of each component is allowed or restricted as follows.
(A) About the ring shaft 2, relative rotation with the ring shaft main body 21, the front ring gear 23, and the back ring gear 24 is made impossible. Further, relative rotation between the ring shaft main body 21 and the front collar 11 and the rear collar 12 is disabled.
(B) For the planetary shaft 4, relative rotation between the planetary shaft main body 41 and the rear planetary gear 44 is allowed.

  In the rotary linear motion conversion mechanism 1, the force is transmitted between these components through the engagement of the screws and gears of the ring shaft 2, the sun shaft 3, and the planetary shafts 4 as follows.

  In the ring shaft 2 and each planetary shaft 4, the ring screw 22 of the ring shaft main body 21 and the planetary screw 42 of each planetary shaft main body 41 are engaged with each other. Further, the front ring gear 23 of the ring shaft main body 21 and the front planetary gear 43 of each planetary shaft main body 41 are engaged with each other. Further, the rear ring gear 24 of the ring shaft main body 21 and the rear planetary gear 44 of each planetary shaft main body 41 are engaged with each other. Thereby, when a rotational motion is input to one of the ring shaft 2 and each planetary shaft 4, the ring screw 22 and the planetary screw 42 mesh, the front ring gear 23 and the front planetary gear 43 mesh, and the back ring A force is transmitted to the other of the ring shaft 2 and each planetary shaft 4 through the meshing of the gear 24 and the rear planetary gear 44.

  In the sun shaft 3 and each planetary shaft 4, the sun screw 32 of the sun shaft main body 31 and the planetary screw 42 of each planetary shaft main body 41 are engaged with each other. Further, the front sun gear 33 of the sun shaft main body 31 and the front planetary gear 43 of each planetary shaft main body 41 are engaged with each other. Further, the rear sun gear 34 of the sun shaft main body 31 and the rear planetary gear 44 of each planetary shaft main body 41 are engaged with each other. Thus, when rotational motion is input to one of the sun shaft 3 and each planetary shaft 4, the sun screw 32 and the planetary screw 42 are engaged, the front sun gear 33 and the front planetary gear 43 are engaged, and the rear sun gear 34. A force is transmitted to the other of the sun shaft 3 and each planetary shaft 4 through meshing with the rear planetary gear 44.

  As described above, the rotational linear motion conversion mechanism 1 includes the ring ring 22 of the ring shaft 2, the sun screw 32 of the sun shaft 3, and the planetary screw 42 of each planetary shaft 4, the front ring gear 23, A speed reduction mechanism constituted by the front sun gear 33 and each front planetary gear 43 and a speed reduction mechanism constituted by the rear ring gear 24, the rear sun gear 34 and each rear planetary gear 44 are provided.

<About the operation mode of the rotating linear motion conversion mechanism>
In the rotational linear motion conversion mechanism 1, an operation method (motion conversion method) for converting rotational motion into linear motion is determined based on the setting mode of the number of teeth of each gear and the number of threads of each screw. That is, as a motion conversion method, either a sun axis displacement method in which the sun shaft 3 is linearly moved by the rotational motion of the ring shaft 2 or an annular shaft displacement method in which the ring shaft 2 is linearly moved by the rotational motion of the sun shaft 3 is selected. Can be selected. Hereinafter, the operation | movement aspect of the rotation linear motion conversion mechanism 1 in each motion conversion system is demonstrated.

  (A) When the solar axis displacement method is adopted as the motion conversion method, conversion from rotational motion to linear motion is performed as follows. That is, when rotational motion is input to the ring shaft 2, the front ring gear 23 and the front planetary gear 43 are engaged, the rear ring gear 24 and the rear planetary gear 44 are engaged, and the annular screw 22 and each planetary gear. By transmitting a force from the ring shaft 2 to each planetary shaft 4 through meshing with the screw 42, each planetary shaft 4 revolves around the sun shaft 3 while rotating. Then, in accordance with the planetary motion of the planetary shaft 4, the front planetary gears 43 and the front sun gear 33 are engaged, the rear planetary gears 44 and the rear sun gear 34 are engaged, and the planetary screws 42 and the sun screws 32 are engaged. Through transmission of force from each planetary shaft 4 to the sun shaft 3, the sun shaft 3 is displaced in the axial direction.

  (B) In the case where the annular shaft displacement method is adopted as the motion conversion method, conversion from rotational motion to linear motion is performed as follows. That is, when rotational motion is input to the sunshaft 3, the front sun gear 33 and each front planetary gear 43 are engaged, the rear sun gear 34 and each rear planetary gear 44 are engaged, and the sun screw 32 and each planetary screw 42. When the force is transmitted from the sun shaft 3 to the planetary shafts 4 through the meshing, the planetary shafts 4 revolve around the sun shaft 3 while rotating. In accordance with the planetary motion of the planetary shaft 4, the front planetary gears 43 and the front ring gear 23 are engaged, the rear planetary gears 44 and the rear ring gear 24 are engaged, and the planetary screws 42 and the annular screws 22. When the force is transmitted from each planetary shaft 4 to the ring shaft 2 through the meshing with the ring shaft 2, the ring shaft 2 is displaced in the axial direction.

  On the other hand, in the rotational linear motion conversion mechanism 1, the front ring gear 23 of the ring shaft 2 meshes with the front planetary gear 43 of each planetary shaft 4, and the front planetary gear 43 meshes with the front sun gear 33 of the sun shaft 3. It is like that. In the rotary linear motion conversion mechanism 1, the rear ring gear 24 of the ring shaft 2 meshes with the rear planetary gear 44 of each planetary shaft 4, and the rear planetary gear 44 meshes with the rear sun gear 34 of the sun shaft 3. It has become.

  Therefore, the reduction ratio of the rotational linear motion conversion mechanism 1 is determined by the engagement of the front ring gear 23, the front sun gear 33, and the front planetary gear 43, and the engagement of the rear ring gear 24, the rear sun gear 34, and the rear planetary gear 44. The Therefore, the effective diameters of the ring screw 22 of the ring shaft 2, the sun screw 32 of the sun shaft 3, and the planetary screw 42 of the planetary shaft 4 vary due to the processing accuracy of the screws, or contact surfaces of the screws to be screwed together. Even if it changes due to wear or the like, the reduction ratio of the rotary linear motion conversion mechanism 1 is maintained at a stable and constant value without being affected by the effective diameter of such a screw. The setting accuracy of the lead of the motion conversion mechanism 1 is also maintained high.

<About the manufacturing method of the rotation linear motion conversion mechanism>
With reference to FIGS. 11-27, the manufacturing method of the rotation linear motion conversion mechanism 1 is demonstrated.
In the present embodiment, a rotating linear motion conversion mechanism is manufactured including the following steps A to H.

  [Step A (FIG. 11)] The ring shaft main body 21, the sun shaft main body 31, each planetary shaft main body 41, the front ring gear 23, the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 are cleaned.

  [Step B (FIG. 12)] After step A, each planetary shaft body 41 is assembled to the sun shaft body 31. As a result, the assembly constituted by the sun shaft main body 31 and each planetary shaft main body 41 is assembled as the first assembly 51.

  [Step C (FIG. 13)] After step B, the ring shaft main body 21 is assembled to the first assembly 51. As a result, the assembly composed of the first assembly 51 and the ring shaft main body 21 is assembled as the second assembly 52.

  [Step D (FIG. 14)] After step C, the front ring gear 23 is attached to the second assembly 52. As a result, the assembly constituted by the second assembly 52 and the front ring gear 23 is assembled as the third assembly 53. Specifically, the front ring gear 23 is assembled at a predetermined position of the ring shaft main body 21 by being press-fitted in a state where it is meshed with each front planetary gear 43. In the present embodiment, the process B, the process C, and the process D correspond to the assembly process, and the third assembly 53 corresponds to the shaft assembly.

  [Step E (FIGS. 15 to 18)] The rear ring gear 24, the rear sun gear 34, and the rear planetary gear 44 used for assembling the rear ring gear 24 and the rear planetary gear 44 to the third assembly 53 are mounted on the rear surfaces thereof. The ring gear 24, the back sun gear 34, and each back planetary gear 44 are attached.

  Here, the rotary linear motion conversion mechanism 1 (see FIG. 7) is manufactured such that the ring shaft main body 21, the sun shaft main body 31, and each planetary shaft main body 41 are in the reference posture. The reference posture is a posture in which the rotation center of the ring shaft main body 21, the rotation center of the sun shaft main body 31, and the revolution center of each planetary shaft main body 41 coincide with each other, and the center line of each planetary shaft main body 41 is the ring shaft. The posture is parallel to the center line of the main body 21 and the sun shaft main body 31.

  It has been confirmed by the present inventor that the planetary shaft 4 is inclined with respect to the reference posture between the ring shaft 2 and the sun shaft 3 during the manufacturing process of the rotational linear motion conversion mechanism 1. When the planetary shaft 4 is inclined as described above, the engagement of the screws (ring screw 21, sun screw 31, planetary screw 42) of each component (ring shaft 2, sun shaft 3, planetary shaft 4) is established. Due to the non-uniformity, local thread wear is promoted, leading to a reduction in life. Further, since the friction between the components increases, the conversion efficiency from the rotational motion to the linear motion (specifically, the operation speed with respect to the input) is also reduced.

  The reason why the planetary shaft 4 is inclined as described above can be considered as follows. In the rotational linear motion conversion mechanism 1, the meshing portion of the ring screw 22 of the ring shaft 2 and the planetary screw 42 of each planetary shaft 4, and the meshing of the sun screw 32 of the sunshaft 3 and the planetary screw 42 of each planetary shaft 4 are engaged. A backlash is formed in the portion. Therefore, when a force is applied to the planetary shaft 4 in combination with each component in the manufacturing process of the rotating linear motion conversion mechanism 1, the planetary shaft 4 is moved in a direction to fill the backlash, thereby causing the planetary shaft to move. The rotary linear motion conversion mechanism 1 may be assembled with the 4 tilted.

  In the present embodiment, in order to prevent the rotation linear motion conversion mechanism 1 from being assembled in this manner, the back ring gear 24, the back sun gear 34, and the back planetary gears 44 are attached using the assembly jig 6. The third assembly 53 is assembled. Step E is a step of attaching the back ring gear 24, the back sun gear 34, and each back planetary gear 44 to the assembly jig 6. In the present embodiment, this step E corresponds to a gear attachment step.

FIG. 15 shows a planar structure of the assembling jig 6, and FIG. 16 shows a side structure of the assembling jig 6.
As shown in FIGS. 15 and 16, the assembling jig 6 includes a base 61 formed in a cylindrical shape, and a plurality of (a book) having a shape protruding from one end (right side in FIG. 15) in the axial direction of the base 61. In the embodiment, nine insertion portions 62 are provided. The base portion 61 and each insertion portion 62 are integrally formed, and each insertion portion 62 has a shape that passes through the same circumference and extends in parallel with each other.

  Each insertion portion 62 corresponds to a portion surrounded by the ring shaft main body 21, the sun shaft main body 31, the planetary shaft main body 41, and the front ring gear 23 in the third assembly 53 (see FIG. 14). More specifically, the ring shaft main body 21, the sun shaft main body 31, and the planetary shaft main body 41 are formed in a shape corresponding to the enclosed portion when the posture is the reference posture. Specifically, each insertion portion 62 has a shape that can be inserted into the surrounding portion without moving the shaft main bodies 21, 31, 41 when the postures of the shaft main bodies 21, 31, 41 are the reference postures. It is formed. Further, each insertion portion 62 presses the screw or gear tip of each shaft body 21, 31, 41 so that the same posture becomes the reference posture when the posture of each shaft body 21, 31, 41 is not the reference posture. Thus, it is formed into a shape that can be inserted while being moved.

  Further, each insertion portion 62 is set such that the diameter of an imaginary line connecting the inner peripheral surfaces thereof is substantially equal to (in detail, slightly larger) the diameter of the tip circle of the rear sun gear 34. In step E, the rear sun gear 34 is attached to a portion (attachment portion 63) closest to the base 61 of the portion surrounded by each insertion portion 62. Further, a convex portion 64 extending in the axial direction of the base portion 61 is formed at a portion corresponding to the mounting portion 63 on one inner surface of each insertion portion 62. The convex portion 64 is formed in a shape that engages with the rear sun gear 34 when the rear sun gear 34 is attached to the attachment portion 63. By providing the convex portion 64 having such a shape, the relative position between the rear sun gear 34 and each insertion portion 62 is uniquely determined, and the assembly position of the rear sun gear 34 with respect to the third assembly 53 is uniquely determined. Yes.

  On the other hand, a hole 65 extending in the axial direction of the base portion 61 is formed in a portion between the insertion portions 62 in the base portion 61. The hole 65 is formed in a shape corresponding to the shape of the back planetary gear 44. In step E, the rear planetary gears 44 are attached to the holes 65, respectively.

  Further, the outer diameter of the base portion 61 is set larger than the diameter of the imaginary line connecting the outer peripheral surfaces of the insertion portions 62. As a result, a step portion 66 having a shape in which the portion on the base 61 side is larger than the portion on the side of each insertion portion 62 is formed at the boundary portion between the base 61 and each insertion portion 62 in the assembly jig 6. . In step E, the rear ring gear 24 is attached to the step portion 66. The outer diameter of the base portion 61 is set slightly smaller than the inner diameter of the portion (main body gear portion 21C) where the rear ring gear 24 is assembled in the ring shaft main body 21 (see FIG. 4).

Furthermore, a plurality of (eight in the present embodiment) grooves 67 extending in the axial direction are formed on the inner peripheral surface of the cylindrical base 61 at equal angular intervals.
17 shows a planar structure of the assembling jig 6 with the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 attached thereto, and FIG. 18 shows a side structure of the assembling jig 6. ing.

  17 and 18, when the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 are attached to the assembling jig 6, the rear ring gear 24, the rear sun gear 34, and the respective The mounting portion 63, each hole 65, and a step portion 66 (see FIGS. 15 and 16) are formed so that the back planetary gear 44 is in mesh with each other.

  [Step F (FIGS. 19 and 20)] When press-fitting the rear sun gear 34 into the sun shaft main body 31, a jig (press fitting jig 7) used to guide the rear sun gear 34 is used as the sun shaft main body 31 (details). Is attached to the main body gear portion 31C (see FIG. 5). In the present embodiment, this process F corresponds to a jig mounting process.

Hereinafter, a specific structure of the press-fitting jig 7 will be described.
FIG. 19 shows a planar structure of the press-fitting jig 7, and FIG. 20 shows a side structure of the press-fitting jig 7.
As shown in FIGS. 19 and 20, the press-fitting jig 7 is formed in a substantially cylindrical shape. In step F, the press-fitting jig 7 is attached so that the center line of the sunshaft main body 31 and the center line of the press-fitting jig 7 coincide.

  Inside the press-fitting jig 7, a hole having a circular cross section (insertion hole 71) extending from one end face in the center line direction is formed. One end of the sunshaft body 31 is inserted into the insertion hole 71 when the press-fitting jig 7 is attached to the sunshaft body 31.

  The press-fitting jig 7 is formed in a shape in which the radius of the outer peripheral surface becomes smaller from the end (base end) on the side where the insertion hole 71 is opened toward the end (tip) on the opposite side. Further, the shape of the press-fitting jig 7 is such that no step is generated at the contact portion between the press-fitting jig 7 and the main body gear part 31C when the press-fitting jig 7 is attached to the main body gear part 31C (see FIG. 5). The shape is set.

  A convex portion 72 extending in the axial direction is formed on the end surface of the press-fitting jig 7 on the proximal end side. The convex portion 72 engages with the concave portion 35 (see FIG. 5) formed in the main body gear portion 31C of the sun shaft main body 31 when the press-fitting jig 7 is attached to the sun shaft main body 31. In this process F, the press-fitting jig 7 cannot rotate to the sun shaft main body 31 (specifically, the main body gear part 31C) through the engagement between the convex part 72 of the press-fitting jig 7 and the concave part 35 of the sun shaft main body 31. Can be installed in a safe condition.

  A plurality of (eight in this embodiment) cutting blades 73 are formed on the outer peripheral surface of the press-fitting jig 7 so as to protrude outward at equal angular intervals. The cutting blades 73 are provided such that the blade stripes extend in the center line direction and the tooth tips are directed toward the distal end side. In detail, the press-fitting jig 7 is composed of a tip side portion (tip portion 74) having a large gradient of the outer peripheral surface and a base side portion (base end portion 75) having a very small gradient. The cutting edge 73 is formed on the proximal end portion 75 of the press-fitting jig 7.

  In general, when the protrusion is formed in a cylindrical shape whose diameter is reduced toward the tip, a processing method is often employed in which the protrusion is formed by cutting the outer peripheral surface of the base material. When such a processing method is employed, for the convenience of the processing, it is easier to form the protruding portion in the portion having the smaller gradient compared to the portion having the larger gradient on the outer peripheral surface. In this respect, in the present embodiment, since the cutting edge 73 is formed in the base end portion 75 where the gradient of the outer peripheral surface is extremely small, the press-fitting jig 7 can be formed relatively easily. In addition, when the rear sun gear 34 is press-fitted into the main body gear portion 31C of the sun shaft main body 31, the rear sun gear 34 is accurately guided to the main body gear portion 31C by a portion having a large outer peripheral surface gradient (tip portion 74). You can also

  [Step G (FIGS. 21 to 23)] The rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 are assembled to the third assembly 53. In the present embodiment, this process G corresponds to a first assembly process and a second assembly process.

FIG. 21 shows a state where the rear ring gear 24, the rear sun gear 34, and the rear planetary gears 44 are being assembled, and FIG. 22 shows a state where the gears 24, 34, and 44 are assembled.
In step G, first, as shown in FIG. 21, the insertion portions 62 are inserted into the surrounding portions inside the third assembly 53, whereby the rear ring gear 24, the rear sun gear 34, and the rear planetary gears 44 are assembled and repaired. Move the tool 6 together. As a result, as shown in FIG. 22, the back ring gear 24, the back sun gear 34, and each back planetary gear 44 are assembled to the third assembly 53. Specifically, the rear ring gear 24 is press-fitted into the main body gear portion 21C of the ring shaft main body 21, the rear sun gear 34 is press-fitted into the main body gear portion 31C of the sun shaft main body 31, and each rear planetary gear 44 is the main body of the planetary shaft main body 41. It is assembled to the gear part 41C.

  In this step G, each insertion portion 62 of the assembly jig 6 is inserted into the surrounding portion of the third assembly 53, so that the attitude of the ring shaft main body 21, the sun shaft main body 31, and each planetary shaft main body 41 is changed. The reference posture is corrected. Further, since the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 are assembled to the third assembly 53, the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 are assembled. The gear mechanism (the guide mechanism) constituted by can be assembled properly.

  Further, since the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 are attached to the assembly jig 6 (step E), the insertion portion 62 of the assembly jig 6 is provided. Each of 24, 34, and 44 can be assembled to the third assembly 53 through one process (process G) of inserting into the surrounding portion of the third assembly 53.

  Then, after assembling the assembly including the third assembly 53, the back ring gear 24, the back sun gear 34, and the back planetary gears 44 as the fourth assembly 54, as shown in FIG. The assembly jig 6 and the press-fitting jig 7 are removed from the fourth assembly 54.

  In step G, in the process of moving the assembly jig 6 described above, the press-fitting jig 7 (FIG. 21) is inserted into the back sun gear 34 and passes through the inside. At that time, the cutting blade 73 projecting from the outer peripheral surface of the press-fitting jig 7 extends in the moving direction (specifically, in the direction of the center line of the sun shaft main body 31) to the inner peripheral surface of the rear sun gear 34. A groove is formed.

  Here, in the rotational linear motion conversion mechanism 1 according to the present embodiment, when the phase difference between the front sun gear 33 and the rear sun gear 34 becomes large and each planetary shaft 4 is tilted, as described above, The error between the design value and the actual value becomes large, and further, as shown in FIG. 24, the conversion efficiency becomes low.

  Therefore, when the back sun gear 34 is press-fitted and fixed to the sun shaft main body 31, the back sun gear 34 and the sun shaft main body 31 do not rotate relative to each other when rotational torque is input to the back sun gear 34 or the sun shaft main body 31. It is necessary to fix the back sun gear 34 and the sun shaft body 31 with such strength that can withstand such rotational torque. According to the present embodiment, the groove formed on the inner peripheral surface of the back sun gear 34 by the cutting edge 73 of the press-fitting jig 7 increases the friction coefficient of the inner peripheral surface as compared with the case where the groove is not formed. And the strength limit for the rotational torque can be increased.

  FIG. 25 shows the press-fitting length required for press-fitting the rear sun gear 34 into the sun shaft main body 31 (specifically, in the center line direction at the contact portion between the inner peripheral surface of the rear sun gear 34 and the outer peripheral surface of the main body gear portion 31C. The relationship between the length) and the strength limit is shown. In FIG. 25, the line L1 indicates the above relationship when a groove is formed on the inner peripheral surface of the back sun gear 34, and the line L2 indicates the above relationship when the groove is not formed. As apparent from FIG. 25, the above-mentioned strength limit is increased by forming a groove on the inner peripheral surface of the rear sun gear 34.

  The above-mentioned strength limit is a press-fitting allowance for press-fitting the rear sun gear 34 into the sun shaft body 31 (specifically, the difference between the diameter of the inner peripheral surface of the rear sun gear 34 and the diameter of the outer peripheral surface of the main body gear portion 31C). ) Can also be increased. However, as shown in FIG. 26, as the press-fitting allowance increases, the deformation amount of the rear sun gear 34 increases. Therefore, if the press-fitting allowance increases excessively, the rear sun gear 34 deforms unnecessarily and leads to the rotation linear motion conversion mechanism 1. The setting accuracy will be reduced.

  On the other hand, as shown in FIG. 25, the strength limit can be increased by increasing the press-fitting length. However, in the rotary linear motion conversion mechanism 1 according to the present embodiment, the space where the rear sun gear 34 can be arranged is limited, and it is difficult to sufficiently increase the press-fitting length.

  Normally, when an annular member is press-fitted and fixed to a cylindrical member, the end of each member is formed in a so-called tapered shape so as to guide the press-fitting. This taper shape is one factor that limits the press-fitting length.

  In the present embodiment, the press-fitting jig 7 (FIG. 21) guides the press-fitting of the back sun gear 34 into the sun shaft main body 31, so that the end of the inner peripheral surface of the back sun gear 34 and the sun shaft main body 31 It is not necessary to form the end of the outer peripheral surface (specifically, the tip of the main body gear portion 31C) in a tapered shape. Actually, the end portion of the inner peripheral surface of the back sun gear 34 and the end portion of the outer peripheral surface of the sun shaft main body 31 are not formed in a tapered shape. Therefore, in the rotary linear motion conversion mechanism 1, the press-fitting allowance can be increased by the amount of the portion not formed in the taper shape as compared with the end portions formed in the taper shape. The strength limit can be increased.

  By the way, when a groove is formed on the inner peripheral surface of the back sun gear 34 by the cutting edge 73 of the press-fitting jig 7, the press-fitting jig 7 rotates around the center line of the sun shaft main body 31 and extends in a spiral shape. When the rear sun gear 34 is press-fitted into the sun shaft main body 31, a force for rotating the rear sun gear 34 may be applied by the groove. This is not preferable because it causes a shift in the position where the rear sun gear 34 is assembled.

  In this regard, in the present embodiment, the press-fitting jig 7 does not rotate around the center line of the sun shaft main body 31 through the engagement between the convex portion 72 of the press-fitting jig 7 and the concave portion 35 of the sun shaft main body 31. Therefore, the extending direction of the groove formed on the inner peripheral surface of the back sun gear 34 can be the center line direction of the sun shaft main body 31. For this reason, it is possible to accurately prevent the assembly position of the rear sun gear 34 from shifting as described above.

  On the other hand, in the process G, the press-fitting jig 7 is inserted into the assembling jig 6 in the process of moving the assembling jig 6 described above. At that time, when the rear sun gear 34 is assembled at a correct position, the cutting edge 73 of the press-fitting jig 7 is formed in the groove 67 (see FIGS. 15 and 16) formed on the inner peripheral surface of the assembling jig 6. It passes through the inside.

  Here, when the assembling jig 6 rotates around the center line for some reason while the press-fitting jig 7 is passing through the inside of the rear sun gear 34, the cutting blade 73 of the press-fitting jig 7 is subjected to assembling. It comes to hit the tool 6. As a result, the assembling jig 6 cannot be moved, and the rear ring gear 24, the rear sun gear 34, and the rear planetary gears 44 are prevented from being assembled at wrong positions. Further, when a force that rotates the assembling jig 6 around the center line is applied while the press-fitting jig 7 is passing through the inside of the assembling jig 6, the groove 67 of the assembling jig 6. And the assembling jig 6 are prevented from rotating around the central axis through contact with the cutting edge 73 of the press-fitting jig 7. Therefore, even in such a case, it is avoided that the back ring gear 24, the back sun gear 34, and each back planetary gear 44 are assembled at wrong positions.

  As described above, in this embodiment, the back sun gear 34 is assembled at the correct position when the cutting edge 73 of the press-fitting jig 7 passes through the groove 67 (see FIGS. 15 and 16) of the assembling jig 6. This can be confirmed, and the assembly jig 6 can be moved while being guided to the correct position. Therefore, the assembly of the back ring gear 24, the back sun gear 34, and each back planetary gear 44 can be performed appropriately using the assembly jig 6 and the press-fitting jig 7.

  [Step H (FIG. 27)] After step G, the front collar 11 and the back collar 12 are attached to the fourth assembly 54, and the rotary linear motion conversion mechanism 1 is assembled. Specifically, the front collar 11 is attached to the main body gear portion 21B of the ring shaft main body 21 after the O-ring 11B is attached to the front collar 11, and the main body of the ring shaft main body 21 is attached after the O-ring 12B is attached to the rear collar 12. The rear collar 12 is attached to the gear portion 21C.

<Effects of the present embodiment>
As described above, according to the present embodiment, the effects described below can be obtained.

  (1) The rotational linear motion conversion mechanism 1 has a reduction ratio of meshing between the front ring gear 23, the front sun gear 33, and each front planetary gear 43, and the rear ring gear 24, the rear sun gear 34, and each rear planetary gear 44. It is determined by the meshing. Therefore, without being affected by the effective diameters of the annular screw 22, the sun screw 32, and the planetary screw 42, the reduction ratio of the rotary linear motion conversion mechanism 1 is maintained constant in a stable state, and the rotary linear motion conversion mechanism The setting accuracy of 1 lead is also maintained high.

  When manufacturing such a rotational linear motion conversion mechanism 1, each insertion portion 62 of the assembling jig 6 is inserted into the surrounding portion inside the third assembly 53, so that the ring shaft main body 21, the sun shaft main body 31, and each planetar are arranged. The posture of the reshaft main body 41 can be corrected to the reference posture. Then, the rear sun gear 34 is assembled to the sun shaft main body 31 in a state where relative rotation is restricted, and further, the rear ring gear 24 is assembled to the ring shaft main body 21 and the rear planetary shaft 41 is connected to the planetary shaft main body 41. The assembly of the gear 44 can be performed with the gears 24, 34, 44 engaged. Therefore, the guide mechanism constituted by the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44 can be properly assembled, and as a result, the rotary linear motion conversion mechanism 1 can be properly assembled.

  (2) The back ring gear 24, the back sun gear 34, and the back planetary gears 44 are attached to the assembling jig 6 while meshing with each other. Then, the back ring gear 24 is mounted on the ring shaft main body 21, the back sun gear 34 is mounted on the sun shaft main body 31, and the back planetary gear 44 is mounted on the planetary shaft main body 41 by moving together with the assembling jig 6. I made it. Therefore, the back ring gear 24, the back sun gear 34, and the back planetary gears 44 can be assembled through one process of inserting each insertion portion 62 of the assembly jig 6 into the surrounding portion of the third assembly 53. .

  (3) A cylindrical press-fitting jig 7 whose diameter is reduced toward the tip is attached to the main body gear portion 31C of the sun shaft main body 31, and the press-fitting jig 7 is inserted into the rear sun gear 34 while being inserted into the sun shaft main body 31. The rear sun gear 34 is press-fitted. Thus, the press-fitting jig 7 can guide the press-fitting of the back sun gear 34 to the sun shaft main body 31, and the end portion of the inner peripheral surface of the back sun gear 34 and the main body gear portion 31 </ b> C of the sun shaft main body 31. There is no need to form the tip of the outer peripheral surface in a tapered shape. Therefore, the press-fitting allowance for press-fitting the rear sun gear 34 into the sun shaft main body 31 can be lengthened, and the strength limit can be increased.

  (4) As the press-fitting jig 7, one having a cutting edge 73 having a shape protruding outwardly on the outer peripheral surface thereof is used. Therefore, when the press-fitting jig 7 passes through the inside of the rear sun gear 34, a groove can be formed on the inner peripheral surface of the rear sun gear 34 by the cutting blade 73, and thereby the friction coefficient of the inner peripheral surface of the rear sun gear 34. To increase the strength limit.

  (5) As the assembling jig 6, a groove 67 extending in the axial direction of the press-fitting jig 7 is formed on the inner surface of the portion into which the press-fitting jig 7 is inserted. As a result, when the rear sun gear 34 is assembled at the correct position, when the press-fitting jig 7 passes through the assembly jig 6, The blade 73 can be structured to pass through the inside of the groove 67 of the assembly jig 6. If the rear sun gear 34 rotates around the center line with respect to the press-fitting jig 7 due to some cause and the assembly position of the assembling jig 6 is likely to shift, the cutting jig 7 is cut off. A structure in which the blade 73 abuts against the assembly jig 6 can be employed. Therefore, it is possible to assemble the rear sun gear 34 while confirming that it is assembled at the correct position, and it is possible to properly assemble the rear ring gear 24, the rear sun gear 34, and the respective rear planetary gears 44.

  (6) The press-fitting jig 7 includes a distal end portion 74 having a large outer peripheral surface gradient and a proximal end portion 75 having a small gradient, and a cutting edge 73 is formed on the proximal end portion 75. Was used. Therefore, the press-fitting jig 7 having the cutting edge 73 can be formed relatively easily. In addition, when the rear sun gear 34 is press-fitted into the sun shaft main body 31, the rear sun gear 34 can be accurately guided to the sun shaft main body 31 by the tip portion 74 having a large gradient.

(7) The press-fitting jig 7 is attached to the main body gear portion 31C in a non-rotatable state through the engagement with the main body gear portion 31C of the sun shaft main body 31. Thus, the press-fitting jig 7 can be structured not to rotate around the center line of the sun shaft main body 31, and a groove extending in the center line direction of the sun shaft main body 31 is formed on the inner peripheral surface of the back sun gear 34. Therefore, it is possible to accurately prevent the assembly position of the rear sun gear 34 from shifting.
<Other embodiments>
The embodiment described above may be modified as follows.

  A configuration for making the press-fitting jig 7 and the sunshaft main body 31 in a relatively non-rotatable state, for example, forming a concave part in the press-fitting jig 7 and forming a convex part in the main body gear portion 31C of the sunshaft main body 31 Can be arbitrarily changed.

-Instead of the press-fitting jig 7 constituted by the distal end portion 74 and the base end portion 75 having different outer peripheral surface gradients, a press-fitting jig having a uniform outer peripheral surface gradient may be used.
-The groove 67 of the assembling jig 6 may be omitted. In this case, if the radius of the inner peripheral surface of the base 61 is increased so that the cutting edge 73 does not contact the inner peripheral surface of the base 61 of the assembling jig 6 when the press-fitting jig 7 passes. Good.

  If the shape of the assembling jig 6 is a shape that passes through the same circumference and includes a plurality of insertion portions that extend in parallel with each other and a base portion that is integrally formed with the insertion portions, for example, The base of the assembling jig can be arbitrarily changed, for example, the cross section is formed into a polygonal tube shape.

-The cutting edge 73 of the press-fitting jig 7 may be omitted.
Instead of providing the cutting edge 73 on the outer peripheral surface of the press-fitting jig 7, the outer peripheral surface of the press-fitting jig may be formed on a rough surface, for example, by attaching abrasive grains to the outer peripheral surface. Even with such a configuration, the inner peripheral surface of the back sun gear 34 can be roughened when the press-fitting jig passes through the back sun gear 34. Therefore, the friction coefficient of the inner peripheral surface of the rear sun gear 34 can be increased to increase the strength limit.

The back sun gear 34 may be press-fitted into the main body gear portion 31 </ b> C of the sun shaft main body 31 without using the press-fitting jig 7.
The front ring gear 23 and the rear ring gear 24 may be fixed by a method other than press-fitting, for example, using a method using adhesion.

  The rear ring gear 24 and the rear planetary gears 44 may be assembled after the rear sun gear 34 is assembled using the assembly jig 6.

The perspective view which shows the perspective structure of the rotation linear motion conversion mechanism with which the manufacturing method concerning one embodiment which actualized this invention is applied. The perspective view which shows the internal structure of the rotation linear motion conversion mechanism. (A) The top view which shows the planar structure about the ring shaft of the rotation linear motion conversion mechanism. (B) The side view which shows the side structure about the ring shaft. (A) Sectional drawing which shows the cross-sectional structure which follows the centerline about the ring shaft of the rotation linear motion conversion mechanism. (B) Sectional drawing which shows the cross-section of the state which decomposed | disassembled the part about the ring shaft. (A) The top view which shows the planar structure about the sun shaft of the rotation linear motion conversion mechanism. (B) Sectional drawing which shows the cross-sectional structure which follows the centerline about the sun shaft. (A) The top view which shows the planar structure about the planetary shaft of the rotation linear motion conversion mechanism. (B) Sectional drawing which shows the cross-sectional structure which follows the centerline about the planetary shaft. Sectional drawing which shows the cross-sectional structure which follows the centerline about the rotation linear motion conversion mechanism. Sectional drawing which shows the cross-sectional structure which follows the DA-DA line | wire of FIG. 7 about the rotation linear motion conversion mechanism. Sectional drawing which shows the cross-sectional structure which follows the DB-DB line | wire of FIG. 7 about the rotation linear motion conversion mechanism. Sectional drawing which shows the cross-sectional structure which follows the DC-DC line | wire of FIG. 7 about the rotation linear motion conversion mechanism. Process drawing which shows the operation | work aspect in the process A about the manufacturing method of the rotation linear motion conversion mechanism. Process drawing which shows the operation | work aspect in process B about the manufacturing method of the rotation linear motion conversion mechanism. Process drawing which shows the operation | work aspect in process C about the manufacturing method of the rotation linear motion conversion mechanism. Process drawing which shows the operation | work aspect in process D about the manufacturing method of the rotation linear motion conversion mechanism. The top view which shows the planar structure about an assembly jig | tool. The side view which shows the side structure about an assembly jig | tool. The top view which shows the planar structure about the assembly jig | tool of the state which attached each gear. The side view which shows the side structure about the assembly jig | tool of the state which attached each gear. The top view which shows the planar structure about a press-fit jig | tool. The side view which shows the side structure about a press-fit jig | tool. Process drawing which shows the operation | work aspect in the process G about the manufacturing method of a rotation linear motion conversion mechanism. Process drawing which shows the operation | work aspect in process G about the manufacturing method of a rotation linear motion conversion mechanism. Process drawing which shows the operation | work aspect in the process G about the manufacturing method of a rotation linear motion conversion mechanism. The graph which shows the relationship between the phase difference and conversion efficiency of each sun gear about a rotation linear motion conversion mechanism. The graph which shows the relationship between a press fit allowance and an intensity limit. The graph which shows the relationship between press-fit length and the amount of deformation of the back sun gear. Process drawing which shows the operation | work aspect in process H about the manufacturing method of a rotation linear motion conversion mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotary linear motion conversion mechanism, 11 ... Front collar, 11A ... Slide bearing, 11B ... O-ring, 11H ... Oil hole, 12 ... Back collar, 12A ... Slide bearing, 12B ... O-ring, 2 ... Ring shaft (ring) Shaft), 21 ... ring shaft main body (annular shaft main body), 21A ... main body screw part, 21B ... main body gear part, 21C ... main body gear part, 22 ... annular screw, 23 ... front ring gear, 24 ... rear ring gear (Annular gear), 25 ... flange, 3 ... sun shaft (sun shaft), 31 ... sun shaft main body (sun shaft main body), 31A ... main body screw portion, 31B ... main body gear portion, 31C ... main body gear portion (set) Appendices), 32 ... Sun screw, 33 ... Front sun gear, 34 ... Back sun gear (sun gear), 35 ... Recess, 4 ... Planetary shaft (planetary shaft), 41 ... Planetary shaft main body (planetary shaft main body) 41A ... Main body screw part, 41B ... Main body gear part, 41C ... Main body gear part, 42 ... Planetary screw, 43 ... Front planetary gear, 44 ... Rear planetary gear (planetary gear part), 44H ... Bearing hole, 51 ... First assembly 52 ... second assembly, 53 ... third assembly, 54 ... fourth assembly, 6 ... assembly jig, 61 ... base, 62 ... insertion portion, 63 ... mounting portion, 64 ... convex portion, 65 ... hole, 66 ... Step part, 67 ... Groove, 7 ... Press fit jig, 71 ... Insertion hole, 72 ... Convex part, 73 ... Cutting edge, 74 ... Front end part, 75 ... Base end part.

Claims (8)

An annular shaft provided with a space therein, a solar shaft disposed in the annular shaft, and a plurality of planetary shafts disposed around the solar shaft in the annular shaft,
The female screw provided on the annular shaft is an annular screw, the gear provided on the annular shaft is an annular gear, the male screw provided on the solar shaft is a solar screw, and the gear provided on the solar shaft is a sun gear. When the male screw provided on the planetary shaft is a planetary screw and the gear provided on the planetary shaft is a planetary gear, the annular screw, the sun screw, and the planetary screw are engaged with each other; and The other of the annular axis and the sun axis through the planetary movement of the planetary axis accompanying the rotational movement of one of the annular axis and the sun axis; Satisfying the condition that linear motion can be obtained,
The annular shaft includes an annular shaft main body provided with the annular screw and an annular gear portion formed with the annular gear, and the solar shaft is a solar shaft main body provided with the solar screw. And a sun gear portion on which the sun gear is formed, and the planetary shaft includes a planetary shaft body provided with the planetary screw and a planetary gear portion on which the planetary gear is formed. The conversion mechanism is a manufacturing method for manufacturing the conversion mechanism,
An assembly process for assembling a coaxial assembly as an assembly of shafts composed of a combination of the sun shaft, the annular shaft body, and the planetary shaft body;
The sun gear portion is attached to an assembling jig having a plurality of insertion portions that can be inserted into a portion surrounded by the sun shaft, the planetary shaft, and the annular shaft inside the shaft assembly. A gear mounting process for mounting in a non-rotatable state through engagement with a tool;
A first assembling step of moving the sun gear part together with the assembling jig through the insertion of the insertion part into the surrounded part and assembling the sun shaft body;
A second set in which the planetary gear portion is assembled to the planetary shaft body and the annular gear portion is assembled to the annular shaft body while meshing the sun gear, the planetary gear, and the annular gear. A method for manufacturing a rotating linear motion conversion mechanism, comprising: an attaching step. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 1,
The gear attachment step is a step of attaching the sun gear, the planetary gear, and the annular gear to an assembly jig while meshing with each other,
In the first and second assembling steps, the sun gear portion is moved to the sun shaft main body, the planetary gear portion is moved to the planetary shaft main body, and the annular gear is moved together with the assembling jig. This is a process of assembling the parts to the ring shaft main body, respectively. A method for producing a rotational linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 1 or 2,
The sun gear portion is formed in an annular shape, and is press-fitted and fixed to a columnar assembly portion formed in the sun shaft main body,
Prior to the first assembling step, the assembly further includes a jig attaching step for attaching a cylindrical press-fitting jig whose diameter is reduced toward the tip end,
In the first assembly step, the press-fitting jig is inserted into the sun gear portion. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 3,
A method for manufacturing a rotary linear motion conversion mechanism, wherein the press-fitting jig is formed with a cutting blade having a shape protruding outward on an outer peripheral surface thereof. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 4,
The first assembling step is a step of inserting the press-fitting jig into the assembling jig,
A method of manufacturing a rotary linear motion conversion mechanism, wherein a groove extending in the center line direction of the press-fitting jig is formed on the inner surface of the portion into which the press-fitting jig is inserted as the assembly jig. . In the manufacturing method of the rotation linear motion conversion mechanism according to claim 4 or 5,
The press-fitting jig is composed of a distal end portion having a large gradient on the outer peripheral surface and a proximal end portion having a small gradient, and the cutting blade is formed on the proximal end portion. Manufacturing method of rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism as described in any one of Claims 4-6,
In the jig attaching step, the press-fitting jig is attached to the assembling part in a non-rotatable state through engagement with the assembling part of the solar shaft main body. Production method. In the manufacturing method of the rotation linear motion conversion mechanism as described in any one of Claims 1-7,
The rotary linear motion conversion mechanism includes a first annular gear and a second annular gear as the annular gear, and the first annular gear is provided at one end of the annular shaft. The second annular gear is provided at the other end, the first annular gear is provided in the annular shaft main body, and the second annular gear is formed in the annular gear portion. And the first sun gear and the second sun gear as the sun gear are provided at positions sandwiching the sun screw, the first sun gear is provided on the sun shaft body, and the second sun gear is The first planetary gear and the second planetary gear are provided as the planetary gear; the first planetary gear is provided at one end of the planetary shaft; The second planetary gear is provided at the end The first planetary gear is provided on the planetary shaft body and the second planetary gear is formed on the planetary gear portion, the first annular gear, the first sun gear, and the first The first planetary gear satisfies the conditions of meshing with the second annular gear, the second sun gear, and the second planetary gear. A method for manufacturing a rotary linear motion conversion mechanism.

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