WO2021065354A1

WO2021065354A1 - Extension and contraction mechanism and method for manufacturing extension and contraction mechanism

Info

Publication number: WO2021065354A1
Application number: PCT/JP2020/033670
Authority: WO
Inventors: 道夫大橋
Original assignee: 三井金属アクト株式会社
Priority date: 2019-10-01
Filing date: 2020-09-04
Publication date: 2021-04-08
Also published as: JP2021055803A; CN217620681U

Abstract

Provided is an extension and contraction mechanism that enables cost reduction with a convenient mechanism. An extension and contraction mechanism (10) is provided with: a shaft (32) and a back-and-forth pipe (22) disposed coaxially with respect to a reference axis line (J); a motor (28) that rotates the shaft (32); a base-end pipe (20) that holds the back-and-forth pipe (22) non-rotatably and movably back and forth along the reference axis line (J); a plurality of rollers (46) disposed in an inner cavity of the back-and-forth pipe (22); and a roller holder (44) that rotates integrally with the shaft (32) and holds a plurality of rollers (88) rotatably. Each of the plurality of rollers (46) is brought into contact with an outer peripheral face of the shaft (32), and is held by the roller holder (44) such that a central axis thereof forms an inclined angle θ with respect to the reference axis line (J). At least one of an outer peripheral face of the roller (46) and the outer peripheral face of the shaft (32) is an elastic body, and at least one thereof has been subjected to a non-slip treatment.

Description

Telescopic mechanism and telescopic mechanism manufacturing method

The present invention relates to an expansion / contraction mechanism and a method for manufacturing an expansion / contraction mechanism.

The telescopic mechanism is used in vehicle tailgate drive devices and robots. The tailgate drive of the vehicle automatically opens and closes the tailgate by expanding and contracting. The telescopic mechanism used as a tailgate drive includes a base end side cover tube oscillatingly connected to the body and a housing tube oscillatingly connected to the tailgate, one on the other. On the other hand, by advancing and retreating, the tailgate is opened and closed by expanding and contracting as a whole. A motor and a spindle are used for advancing and retreating the cover tube and the housing tube (see, for example, Patent Document 1 and Patent Document 2).

The rotation of the motor is decelerated by the reduction mechanism and transmitted to the lead screw directly or via an intermediate member. A nut that cannot rotate and can move forward and backward in the axial direction is screwed onto the lead screw. The nut advances and retreats due to the rotation of the lead screw to drive the pipe connected to the nut in the axial direction. In the tailgate drive device, an excessive axial external force may be applied when the tailgate is operated by a person, so that a clutch mechanism for cutting the external force may be provided.

Japanese Patent No. 4430044 Japanese Patent No. 6009094

With the expansion and contraction mechanism as described above, there is a concern that the resistance between the nut and the screw will increase due to the deviation of the meshing angle between the lead screw and the nut and the linearity of the lead screw, and the expected propulsive force cannot be obtained. High-precision parts and precise assembly are required, resulting in high costs.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an expansion / contraction mechanism and a method for manufacturing an expansion / contraction mechanism that can realize a low cost with a simple mechanism.

In order to solve the above-mentioned problems and achieve the object, the expansion / contraction mechanism according to the present invention rotates one of the shaft and the advancing / retreating pipe provided coaxially with the reference axis and the shaft and the advancing / retreating pipe. The drive source to be driven, the base body that holds the other non-rotatably and freely advancing and retreating along the reference axis, a plurality of rollers provided in the lumen portion of the advancing and retreating pipe, and the advancing and retreating pipe are integrally rotated. A roller holder for rotatably holding the plurality of rollers is provided, and the plurality of rollers are in contact with the outer peripheral surface of the shaft, respectively, and the rollers have an inclination angle with respect to the reference axis. It is characterized in that it is held by a holder.

At least one of the outer peripheral surface of the roller and the outer peripheral surface of the shaft may be an elastic body.

A non-slip treatment may be applied to at least one surface of the outer peripheral surface of the roller and the outer peripheral surface of the shaft.

The roller holder may include a pressing means for elastically pressing a plurality of the rollers against the outer peripheral surface of the shaft.

The roller may have a shape in which the axial length is larger than the maximum diameter, the central portion is the maximum diameter portion, and the diameter is small toward both sides along the axial direction.

The plurality of rollers may be arranged in parallel at equal intervals along the circumferential direction centered on the reference axis, and adjacent rollers may be provided so as to overlap each other in the direction along the reference axis.

One end may be provided with a base end end portion that is swingably connected to the tailgate of the vehicle, and the other end may be provided with a tip end portion that is swingably connected to the main body of the vehicle.

The inner diameter of the shaft may change along the reference axis.

A spring may be provided that elastically biases the shaft and the advancing / retreating pipe in a direction in which the shaft and the advancing / retreating pipe are separated from each other along the reference axis.

A support cylinder for supporting the spring from the inner surface may be provided between the advancing / retreating pipe and the spring.

Further, the expansion / contraction mechanism manufacturing method according to the present invention is a expansion / contraction mechanism manufacturing method for manufacturing the expansion / contraction mechanism, and is a step of fixing a power transmission unit having a plurality of the rollers mounted on the roller holder to the shaft. A step of providing a proximal spring receiving portion for supporting the proximal end portion of the spring on the proximal end side of the advancing / retreating pipe, and the power of the proximal end side of the advancing / retreating pipe provided with the proximal spring receiving portion. A step of covering the transmission unit, a step of inserting the spring into the inside from the tip side of the advancing / retreating pipe, and a tip spring receiver that supports the tip of the spring with respect to the tip of the advancing / retreating pipe into which the spring is inserted. It is characterized by having a step of fixing the portion.

In the expansion / contraction mechanism and the expansion / contraction mechanism manufacturing method according to the present invention, it is sufficient that a plurality of rollers having an inclination angle with respect to the reference axis are in contact with each other so as to generate an appropriate frictional force with respect to the outer peripheral surface of the shaft, and the accuracy is high. It is a simple mechanism that does not need to have the above configuration. That is, dimensional errors such as the shape of the roller, the inclination angle, and the inner diameter of the advancing / retreating pipe are allowed to some extent, and the assembly accuracy is also allowed to some extent, so that low cost can be realized.

FIG. 1 is a perspective view showing a telescopic mechanism according to the first embodiment and a vehicle equipped with the telescopic mechanism. 2A and 2B are expansion and contraction mechanisms according to the first embodiment, FIG. 2A is a perspective view showing a stretched state, and FIG. 2B is a perspective view showing a contracted state. FIG. 3 is a partial cross-sectional perspective view of the connection portion between the base end pipe and the tip end pipe. FIG. 4 is a cross-sectional side view of the expansion / contraction mechanism according to the first embodiment. 5A and 5B are perspective views of an internal mechanism in the expansion / contraction mechanism according to the first embodiment, FIG. 5A is a perspective view showing a stretched state, and FIG. 5B is a perspective view showing a contracted state. FIG. 6 is a perspective view of the power transmission unit and its periphery in the internal mechanism of the expansion / contraction mechanism according to the first embodiment. 7 is an enlarged perspective view of the periphery of the power transmission unit in the internal mechanism shown in FIG. 6. FIG. FIG. 8 is an enlarged side view of the periphery of the power transmission unit in the internal mechanism shown in FIG. FIG. 9 is a partially exploded perspective view of the power transmission unit according to the first embodiment. FIG. 10 is a cross-sectional side view of the power transmission unit and its periphery in the internal mechanism of the expansion / contraction mechanism according to the first embodiment. 11A and 11B are views of the six rollers and the advancing / retreating pipe in the power transmission unit according to the first embodiment as viewed from the direction of the reference axis, FIG. 11A is a diagram showing the first example thereof, and FIG. 11B is a diagram showing the first example thereof. It is a figure which shows the 2nd example. FIG. 12 is a partially exploded perspective view of the power transmission unit according to the modified example. FIG. 13 is a flowchart of a method of manufacturing the expansion / contraction mechanism according to the first embodiment. FIG. 14 is a schematic side sectional view showing the expansion / contraction mechanism according to the second embodiment. FIG. 15 is a cross-sectional side view of the expansion / contraction mechanism according to the second embodiment. FIG. 16 is an exploded perspective view of the expansion / contraction mechanism according to the second embodiment. FIG. 17 is a perspective view showing a tip end portion of the expansion / contraction mechanism according to the second embodiment. 18A and 18B are perspective views of an internal mechanism in the expansion / contraction mechanism according to the second embodiment, FIG. 18A is a perspective view showing a stretched state, and FIG. 18B is a perspective view showing a contracted state. FIG. 19 is an exploded perspective view showing the power transmission unit and its related members in the second embodiment. FIG. 20 is a cross-sectional view of the power transmission unit and its related members in the second embodiment as viewed from the direction of the reference axis. FIG. 21 is a side view of the shaft, the roller holder, and the rollers according to the second embodiment. FIG. 22 is a side sectional view showing the power transmission unit and its related members in the second embodiment. FIG. 23-1 is a schematic cross-sectional side view of the expansion / contraction mechanism according to the third embodiment. FIG. 23-2 is a schematic cross-sectional side view of the expansion / contraction mechanism according to the fourth embodiment. FIG. 23-3 is a schematic cross-sectional side view of the expansion / contraction mechanism according to the fifth embodiment.

Hereinafter, embodiments of the expansion / contraction mechanism and the expansion / contraction mechanism manufacturing method according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

FIG. 1 is a perspective view showing an expansion / contraction mechanism 10 according to an embodiment of the present invention and a vehicle 12 equipped with the expansion / contraction mechanism 10. As shown in FIG. 1, the expansion / contraction mechanism 10 is for automatically opening and closing the tailgate 14 of the vehicle 12. A total of two telescopic mechanisms 10 are provided, one on each side of the tailgate 14. The tailgate 14 can be opened and closed with respect to the main body of the vehicle 12 by the hinge 14a. The two telescopic mechanisms 10 have the same structure and operate synchronously, and open the tailgate 14 by extending (the state shown in FIG. 1) and close the tailgate 14 by contracting. That is, the pair of expansion / contraction mechanisms 10 are tailgate drive devices in the vehicle 12. The expansion / contraction mechanism 10 expands / contracts under the action of the control unit based on, for example, a user's button operation. The door of the vehicle that the telescopic mechanism 10 opens and closes may be a ton rank lid, a bonnet, or the like, in addition to the tailgate 14. The number of telescopic mechanisms 10 for opening and closing the tailgate 14 may be one or three or more. The expansion / contraction mechanism 10 is not limited to the application in the vehicle 12, and can be used in various applications such as a robot arm.

The telescopic mechanism 10 has a long shape, and each has a base end end portion 16 that is swingably connected to the tailgate 14 of the vehicle 12 at one end, and swingable to the main body of the vehicle 12 at the other end. The tip end portion (tip spring receiving portion) 18 to be connected is provided. The base end end portion 16 and the tip end end portion 18 are provided with shaft holes so as to be able to swing with respect to the mating member. The expansion / contraction mechanism 10 may be provided in the vehicle 12 in the opposite direction. In addition, in this application, "base end" and "tip" are names which are distinguished for convenience of explanation.

As the expansion / contraction mechanism 10 shown in FIG. 1, specifically, the expansion / contraction mechanisms 10A to 10D according to the first to fourth embodiments described below can be applied. Hereinafter, they will be described in order.

(First Embodiment)
2A and 2B are perspective views of the expansion / contraction mechanism 10A according to the first embodiment, FIG. 2A is a perspective view showing a stretched state, and FIG. 2B is a perspective view showing a contracted state. As shown in FIG. 2A, in appearance, the expansion / contraction mechanism 10A has the base end pipe (base body) 20 and the advancing / retreating pipe 22 arranged coaxially, and the base end side of the base end pipe 20 is the base end end. It is closed by the portion 16, and the tip end side of the advancing / retreating pipe 22 is closed by the tip end portion 18. The base end end portion 16 is fixed to the base end pipe 20, and the tip end end portion 18 is fixed to the advancing / retreating pipe 22. The advancing / retreating pipe 22 has a slightly larger diameter than the base end pipe 20. In the extended state of the telescopic mechanism 10A, the vicinity of the base end portion of the advancing / retreating pipe 22 covers the vicinity of the vicinity of the tip end portion of the base end pipe 20. As shown in FIG. 2B, when the expansion / contraction mechanism 10A is contracted, most of the base end pipe 20 is inserted into the advancing / retreating pipe 22. The length ratio of the expansion / contraction mechanism 10A is about 1.5 times between the expanded state and the contracted state. The advancing / retreating pipe 22 has a series structure in which the first pipe 24 on the proximal end side and the second pipe 26 on the distal end side are connected by a joint 27.

FIG. 3 is a partial cross-sectional perspective view of the connection portion between the base end pipe 20 and the advancing / retreating pipe 22. As shown in FIG. 3, a shallow groove 20a is formed on the outer peripheral surface of the base end pipe 20 along the reference axis J. The groove 20a has a rectangular cross section. Four grooves 20a are provided at 90 ° intervals, and two of them are shown in FIG.

A protrusion 24a is formed at the base end of the first pipe 24 so as to slightly protrude inward and fit into the groove 20a. The protrusion 24a is formed in a rectangular cross section in accordance with the groove 20a, and is formed by, for example, pressing. Four protrusions 24a are provided at 90 ° intervals in accordance with the grooves 20a. Two of them are shown in FIG. The base end pipe 20 and the first pipe 24 are fitted to each other with almost no gap, and the groove 20a and the protrusion 24a are engaged with each other in the circumferential direction so that they cannot rotate relative to each other and can move back and forth relatively along the reference axis J. It has become.

FIG. 4 is a cross-sectional side view of the expansion / contraction mechanism 10A. As shown in FIG. 4, each element of the base end pipe 20 in the expansion / contraction mechanism 10A and the internal mechanism in the advancing / retreating pipe 22 is arranged coaxially along the reference axis J. Inside the base end pipe 20, a motor (drive source) 28, a speed reducer 30, a shaft 32, and a first bearing 34 are provided in this order from the base end side. The motor 28 is arranged on the most proximal side of the proximal pipe 20 and is substantially in contact with the proximal end portion 16. The motor 28 and the speed reducer 30 are fixed to the base end pipe 20 by a caulking portion 20b (see FIG. 2A). The speed reducer 30 is, for example, a planetary gear type. The rotation of the motor 28 is reduced by the speed reducer 30 and transmitted to the shaft 32. The first bearing 34 is provided at substantially the tip of the base end pipe 20, and pivotally supports the shaft 32. The first bearing 34 can prevent the shaft 32 from rotating. The shaft 32 may be pivotally supported by yet another bearing in the vicinity of the speed reducer 30. The outer peripheral surface of the shaft 32 is anti-slip processed (for example, shot peening).

The shaft 32 protrudes further toward the tip side than the base end pipe 20, and the power transmission unit 36 is fitted in the protruding portion. The power transmission unit 36 is arranged near the tip end in the first pipe 24 when the expansion / contraction mechanism 10A is extended, and is arranged near the base end in the first pipe 24 when the expansion / contraction mechanism 10A is contracted. The power transmission unit 36 will be described later. Inside the second pipe 26, a second bearing 38, a spring receiving seat (base end spring receiving portion) 40, and a spring 42 are arranged in order from the base end side.

5A and 5B are perspective views of the internal mechanism of the telescopic mechanism 10A, FIG. 5A is a perspective view showing a stretched state, and FIG. 5B is a perspective view showing a contracted state. Although the base end pipe 20 is omitted in FIG. 5, the advancing / retreating pipe 22 is shown by a virtual line. The base end portion of the spring 42 is supported by the spring receiving seat 40, and the tip end portion is supported by the tip end portion 18. As shown in FIG. 5A, the spring 42 has a natural length or a slightly compressed state when the expansion / contraction mechanism 10A is extended, and the expansion / contraction mechanism 10A contracts as shown in FIG. 5B. In the state, it is considerably compressed. The spring 42 is elastically biased in a direction in which the shaft 32 and the advancing / retreating pipe 22 are separated from each other along the reference axis J. Since the second bearing 38 is provided, the rotation of the power transmission unit 36 is not transmitted to the spring receiving seat 40 and the spring 42, and these do not rotate. The second bearing is a thrust bearing.

FIG. 6 is a perspective view of the power transmission unit 36 and its surroundings in the internal mechanism of the telescopic mechanism 10A. FIG. 7 is an enlarged perspective view of the periphery of the power transmission unit 36 in the internal mechanism shown in FIG. FIG. 8 is an enlarged side view of the periphery of the power transmission unit 36 in the internal mechanism shown in FIG.

The tip end side of the base end pipe 20 is fixed to the outer peripheral portion of the first bearing 34 by a caulking portion 22c. As a result, the inner ring and shaft 32 of the first bearing 34 are rotatable and cannot move forward or backward in the axial direction. The caulking portion 22c is provided in each groove 22a.

On the outer peripheral surface of the first bearing 34, an annular protrusion 34b having a low tip portion and a support protrusion 34c having a short axial direction are provided. When the advancing / retreating pipe 22 is displaced to the most distal end side, the annular protrusion 34b is regulated by contact with the protrusion 24a (see FIG. 3) to prevent the advancing / retreating pipe 22 from coming off. Four support protrusions 34c are provided at 90 ° intervals, and two of them are shown in FIG. The support protrusions 34c are provided at intermediate positions of the four grooves 22a in the circumferential direction. The annular protrusion 34b and the support protrusion 34c have the same height and are supported by abutting the first pipe 24 from the inner peripheral surface. The shaft 32 protrudes toward the tip end through the inner hole 34a of the first bearing 34, and the power transmission unit 36 is fitted in the protruding portion as described above.

FIG. 9 is a partially exploded perspective view of the power transmission unit 36. The power transmission unit 36 includes a roller holder 44, a plurality of rollers 46, and a roller shaft 48 corresponding to the rollers 46. The power transmission unit 36 is provided with six rollers 46, but in FIG. 9, three are shown by solid lines and one is shown by a virtual line for easy understanding. One of the three solid rollers 46 is shown in a disassembled state from the roller holder 44. Each of the six rollers 46 is pivotally supported by the roller shaft 48, but only four are shown in FIG. 9 for easy understanding, and one of them is shown in a state of being disassembled from the roller holder 44. The number of rollers 46 included in the roller holder 44 is not limited to six, and may be, for example, 3 to 12. A plurality of power transmission units 36 may be provided in parallel with respect to the shaft 32 in the axial direction.

The roller holder 44 cannot rotate to the advancing / retreating pipe 22 via the protrusion 27b of the joint 27. The roller holder 44 rotatably holds the six rollers 46. The roller holder 44 is composed of two

arm projecting disks

50 and 52 separated in the axial direction, and six rollers 46 are provided between them. The roller holder 44 may be composed of one component, and for example, the arm protruding disk 50 and the arm protruding disk 52 may be connected to each other by a tubular body at the outer peripheral portion thereof.

The arm protruding disk 50 on the base end side includes a central disk 50a and six arms 50b protruding from the central disk 50a. A hole 50aa through which the shaft 32 passes is formed in the center of the central disk 50a. The arms 50b are L-shaped when viewed from the direction of the reference axis J, and are provided at equal intervals (60 °). The arm 50b includes a portion that protrudes in the radial direction from the central disk 50a and a portion that bends counterclockwise in FIG. 9 at the tip thereof, and a hole 50ba is formed in the vicinity of the tip end. The portion of the arm 50b that is bent counterclockwise is slightly tilted toward the tip side.

The arm protruding disk 52 on the tip side includes a central disk 52a and six arms 52b protruding from the central disk 52a. A hole 52aa through which the shaft 32 passes is formed in the center of the central disk 52a. That is, the rotation of the shaft 32 is not directly transmitted to the roller holder 44 including the

arm protruding disks

50 and 52.

The arms 52b are L-shaped when viewed from the direction of the reference axis J, and are provided at equal intervals (60 °). The arm 52b has a symmetrical shape with the arm 50b. That is, the arm 52b includes a portion that protrudes radially from the central disk 52a and a portion that bends clockwise at the tip thereof, and a hole 52ba is formed in the vicinity of the tip end. The portion of the arm 52b that is bent clockwise is slightly tilted toward the proximal end side.

The roller 46 is a cigar type having a larger diameter at the center than both ends. Specifically, the roller 46 has an axial length larger than the maximum diameter at the center, and the center has the maximum diameter and faces both sides along the axial direction. It has a small diameter. The diameter of each part of the roller 46 is set so as to come into contact with the inner peripheral surface of the first pipe 24 in an appropriate area according to the inclination angle θ (see FIG. 8) described later.

The axial length of the roller 46 is substantially equal to the distance between the held arm 50b and the arm 52b. A hole 46a is formed in the center of the roller 46. The roller 46 (and the roller 88 described later) is an elastic body and is made of a polymer material such as an elastomer or rubber. The roller 46 may have at least an elastic surface.

The roller shaft 48 is a member that is inserted into the hole 46a to rotatably support the roller 46, and press-fitting portions 48a having a slightly smaller diameter are formed at both ends. One of the press-fitting portions 48a is press-fitted into the hole 50ba of the arm 50b, and the other is press-fitted into the hole 52ba of the arm 52b.

Since the arm 50b of the arm protruding disk 50 is bent clockwise and the arm 52b of the arm protruding disk 52 is bent counterclockwise, a roller pivotally supported between the paired arm 50b and the arm 52b. As shown in FIG. 8, the central axis of 46 has an inclination angle θ with respect to the reference axis J. The six rollers 46 are arranged in parallel at equal intervals (60 °) along the circumferential direction centered on the reference axis J, and are well-balanced. Further, the rollers 46 are densely arranged so that adjacent ones overlap each other in the direction along the reference axis J, which is space efficient.

The joint 27 includes a central hole 27a through which the shaft 32 is inserted, a detent protrusion 27b that fits between a pair of adjacent arms 52b, a central disk 27c, a base end disk 27d, and a tip disk 27e. The shaft 32 passes through the central holes 27a and the holes 52aa and 50aa, and further projects toward the tip end side.

FIG. 10 is a cross-sectional side view of the power transmission unit 36 and its periphery in the internal mechanism of the telescopic mechanism 10A. As shown in FIG. 10, the first pipe 24 is fitted and fixed to the base end disk 27d of the joint 27, and the second pipe 26 is fitted and fixed to the tip disk 27e. These fixing means are, for example, caulking. The outer diameters of the base end disk 27d and the tip end disk 27e are substantially equal to the inner diameters of the first pipe 24 and the second pipe 26, and the outer diameter of the central disk 27c is approximately equal to the outer diameters of the first pipe 24 and the second pipe 26. .. The first pipe 24 and the second pipe 26 are in contact with the central disk 27c and have no gap.

FIG. 11A is a view of the six rollers 46 and the first pipe 24 in the power transmission unit 36 as viewed from the direction of the reference axis J. As shown in FIGS. 10 and 11A, the six rollers 46 in the power transmission unit 36 are in contact with the outer peripheral surface of the shaft 32, respectively. Each roller 46 is not in contact with the first pipe 24. Since the outer peripheral surface of the roller 46 is an elastic body and the outer peripheral surface of the shaft 32 is anti-slip processed, a moderately large frictional force is generated between the two.

FIG. 11B is a view seen from the direction of the reference axis J when the roller 46 in the power transmission unit 36 is replaced with the roller 46A according to the modified example. As shown in FIG. 11B, the roller 46A has a smaller diameter at the center than both ends, specifically, has an axial length larger than the maximum diameter at both ends, and has a minimum diameter at the center in the axial direction. It has a shape with a large diameter toward both sides along. When viewed from the direction of the reference axis J, the arc contour of the roller 46A is set so that the diameter is slightly larger than the outer peripheral circle of the shaft 32. As a result, the roller 46A has an appropriate contact area suitable for power transmission because the vicinity of the minimum diameter at the center and the vicinity thereof are in contact with the outer peripheral surface of the shaft 32. The roller 46 in the following description shall include the roller 46A.

In order to generate an appropriately large frictional force between the outer peripheral surface of the roller 46 and the outer peripheral surface of the shaft 32, at least one of them may be an elastic body. Similarly, it is preferable that at least one surface is anti-slip treated. Further, in order to increase the generated frictional force, it is preferable to provide a pressing means for elastically pressing the roller 46 against the outer peripheral surface of the shaft 32. As such a pressing means, for example, as shown in FIG. 12, it is preferable to provide the arm 50bA on the arm protruding disk 50 and the arm 52bA on the arm protruding disk 52. The arms 50bA and 52bA replace the

above arms

50b and 52b, and are provided with springs 50bb and 52bb at the connection portions with the central disks 50a and 52a. The springs 50bb and 52bb have elasticity in the radial direction due to the alternating circumferential grooves. According to the springs 50bb and 52bb as such pressing means, the roller 46 can be suitably pressed against the outer peripheral surface of the shaft 32.

As described above, the expansion / contraction mechanism 10A holds the shaft 32 and the advancing / retreating pipe 22 coaxially provided with respect to the reference axis J and the advancing / retreating pipe 22 so as to be non-rotatable and freely advancing / retreating along the reference axis J. A plurality of rollers 46 provided in the cavity of the advancing / retreating pipe 22 and a roller holder 44 that rotates integrally with the shaft 32 to rotatably hold the plurality of rollers 46 are provided. Each of the plurality of rollers 46 is in contact with the outer peripheral surface of the shaft 32, and is held by the roller holder 44 so that the central axis has an inclination angle θ (see FIG. 8) with respect to the reference axis J.

Since the roller 46 is in contact with the outer peripheral surface of the shaft 32 and the advancing / retreating pipe 22 is configured to be non-rotatable, the motor 28 as a drive source rotates the shaft 32 via the speed reducer 30. Each of the plurality of rollers 46 rotates about the reference axis J in a relative and revolving manner with respect to the shaft 32, and rotates around the roller shaft 48. Since each of the rollers 46 is arranged so as to have an inclination angle θ with respect to the reference axis J, the roller 46 rotates (revolves and rotates), so that the advance / retreat pipe 22 has an axial direction according to the inclination angle θ. The thrust of the above is applied, and the advancing / retreating pipe 22 advances / retreats along the reference axis J. The advancing / retreating direction of the advancing / retreating pipe 22 depends on the rotation direction of the motor 28. When the rotation of the motor 28 is stopped, the advance / retreat of the advance / retreat pipe 22 is stopped. Since a frictional force is generated between the shaft 32 and the roller 46, the position of the advancing / retreating pipe 22 is maintained even if there is no braking mechanism. That is, the power transmission unit 36 can apply a driving force and a holding force to the advancing / retreating pipe 22.

In the expansion / contraction mechanism 10A, by setting the inclination angle θ large, the expansion / contraction speed increases but the driving force decreases, and conversely, by setting the inclination angle θ small, the expansion / contraction speed decreases but the driving force increases. As described above, the inclination angle θ in the expansion / contraction mechanism 10A conceptually corresponds to the advance angle of the screw mechanism. The amount of advance / retreat of the expansion / contraction mechanism 10A may be adjusted by controlling the rotation of the motor 28 based on the signal of the position switch or the sensor.

Since the outer peripheral surface of the roller 46 is an elastic body and the outer peripheral surface of the shaft 32 is anti-slip processed, the frictional force between the two is large, and the rotation of the shaft 32 efficiently advances and retreats to the power transmission unit 36. It is transmitted to the pipe 22. On the other hand, even if some slip occurs between the outer peripheral surface of the roller 46 and the inner peripheral surface of the first pipe 24, the advancing / retreating operation of the expansion / contraction mechanism 10A is not affected.

It is the power transmission unit 36 that converts the rotation of the shaft 32 into thrust and transmits it to the advance / retreat pipe 22. The power transmission unit 36 may be in contact with a plurality of rollers 46 in the direction of the inclination angle θ so as to generate an appropriate frictional force with respect to the outer peripheral surface of the shaft 32, as if the lead screw and the nut are engaged. It is a simple mechanism that does not need to have a highly accurate configuration. That is, errors such as the shape of the roller 46, the inclination angle θ, the outer diameter of the shaft 32, and the linearity of the shaft 32 are allowed to some extent, and the assembly accuracy of the power transmission unit 36 and the expansion / contraction mechanism 10A as a whole also has some errors. Is acceptable and low cost can be realized.

Further, in the mechanism by meshing the lead screw and the nut according to the prior art, when the motor rotation is reversed, the metal surfaces collide with each other due to the influence of so-called backlash and a sound is generated. Since the roller 46 is always in contact with the outer peripheral surface of the shaft 32, no sound is generated even during reverse rotation, and it is not necessary to provide a special cushioning means or sound deadening means. Since there is no backlash, the advancing / retreating pipe 22 has no axial rattling with respect to the base end pipe 20.

When an excessive axial external force is applied to the expansion / contraction mechanism 10A (for example, when the tailgate 14 is manually opened or closed), the roller 46 comes into contact with the inner peripheral surface of the first pipe 24. The portion exceeds the limit of friction holding and slippage occurs between the two. Then, the external force is not transmitted to the power transmission unit 36, the shaft 32, and the motor 28 even if there is no special clutch mechanism. Therefore, the power transmission unit 36 is not deformed, the shaft 32 does not buckle, or the motor 28 does not generate a counter electromotive force.

Since the spring 42 elastically biases the shaft 32 and the advancing / retreating pipe 22 in the direction away from each other along the reference axis J, the spring 42 complements the force in the extending direction when the expansion / contraction mechanism 10A operates in the extending direction, and the tailgate. Even when 14 is considerably heavy, the door opening operation is possible. Further, in the case of a light load, the spring 42 may be omitted.

FIG. 13 is a flowchart of a manufacturing method of the expansion / contraction mechanism 10A. As shown in FIG. 13, in order to manufacture the telescopic mechanism 10, six rollers 46 are attached to the roller holder 44 in step S1 to assemble the power transmission unit 36. In step S2, the base end end portion 16, the motor 28, the speed reducer 30, the shaft 32, and the first bearing 34 are assembled with respect to the base end pipe 20. The base end pipe 20 is fixed by the groove 20a of the first bearing 34 and the caulking portion 20c. In step S3, the power transmission unit 36 is fitted into the shaft 32. The first pipe 24 and the second pipe 26 are connected by a joint 27 to form an advancing / retreating pipe 22. In step S4, the spring receiving seat 40 is provided on the first pipe 24 of the advancing / retreating pipe 22. In step S5, the power transmission unit 36 is covered with the base end side of the advancing / retreating pipe 22 provided with the spring receiving seat 40. Further, a protrusion 24a is formed on the advancing / retreating pipe 22 so as to enter the groove 20a of the base end pipe 20. In step S6, the spring 42 is inserted into the inside through the opening on the tip end side of the advancing / retreating pipe 22. The spring 42 is urged by a spring receiving seat 40 provided in advance inside the advancing / retreating pipe 22. In step S7, the tip end portion 18 is fixed to the tip of the advancing / retreating pipe 22 into which the spring 42 is inserted.

In such a method of manufacturing the expansion / contraction mechanism 10A, the advancing / retreating pipe 22 is attached to the base end pipe 20 and the power transmission unit 36, and then the spring 42 is inserted into the inside from the tip side of the advancing / retreating pipe 22. Easy and correct assembly.

The expansion / contraction mechanism 10A includes a first portion including a base end pipe 20, a motor 28, a speed reducer 30, and a shaft 32 on the base end side, a power transmission unit 36 on the tip end side, an advancing / retreating pipe 22, a spring receiving seat 40, and a spring 42. Although it has a second part including the second part, a plurality of types having different lengths are prepared for the second part, and the first part is appropriately selectively selected according to the type of the vehicle 12 and the type of the tailgate 14. It may be attached.

(Second embodiment)
Next, the expansion / contraction mechanism 10B according to the second embodiment will be described. Hereinafter, in the description of the expansion / contraction mechanisms 10B to 10D according to the second to fourth embodiments, the same components as those of the expansion / contraction mechanism 10A are designated by the same reference numerals, and detailed description thereof will be omitted.

14A and 14B are perspective views of the expansion / contraction mechanism 10B according to the second embodiment, FIG. 14A is a perspective view showing a stretched state, and FIG. 14B is a perspective view showing a contracted state. As shown in FIG. 14A, the expansion / contraction mechanism 10B is substantially the same as the expansion / contraction mechanism 10A (see FIG. 2) in appearance, and the base end pipe 20 and the tip end pipe 70 are arranged coaxially. It is a configuration that is. The tip pipe 70 has a double structure in which the inner advancing / retreating pipe 72 (see FIG. 15) and the outer outer pipe 74 are fitted and fixed. The tip pipe 70 corresponds to the above-mentioned advancing / retreating pipe 22, but the function of advancing / retreating with respect to the shaft 32 corresponds to the advancing / retreating pipe 72, and the function of the housing corresponds to the outer pipe 74. A ring cover 76 is provided at the base end of the outer pipe 74.

FIG. 15 is a cross-sectional side view of the expansion / contraction mechanism 10B. FIG. 16 is an exploded perspective view of the telescopic mechanism 10B. In FIG. 16, some elements such as the outer pipe 74 are omitted.

As shown in FIGS. 15 and 16, each element of the base end pipe 20 in the telescopic mechanism 10B and the internal mechanism in the tip end pipe 70 is arranged coaxially along the reference axis J. Inside the base end pipe 20, a motor (drive source) 28, a speed reducer 30, a shaft 32, a bearing 78, and a spring receiving seat 40 are provided in this order from the base end side. The base end portion of the spring 42 is supported by the spring receiving seat 40, and the tip end portion is supported by the tip end portion 18. The bearing 78 and the spring receiving seat 40 are provided substantially adjacent to the speed reducer 30. The bearing 78 pivotally supports the end of the shaft 32.

The shaft 32 projects in the hollow portion of the spring 42 toward the tip side. The power transmission unit 80 is fitted in the shaft 32. The power transmission unit 80 will be described later. Inside the outer pipe 74, an advancing / retreating pipe 72, a spring guide (support cylinder) 82, and a spring 42 are provided coaxially from the center. The advancing / retreating pipe 72, the spring guide 82, and the spring 42 are fitted to each other with almost no gap (see FIG. 22).

The advancing / retreating pipe 72 is a member that advances / retreats with respect to the shaft 32, extends from the tip end portion 18 toward the base end side, and its length is, for example, about 70% of the outer pipe 74. The spring guide 82 is a member that supports the spring 42 from the inner surface, extends from the tip end portion 18 toward the base end side, and its length is longer than that of the advancing / retreating pipe 72, for example, 80% of the outer pipe 74. Degree. By being supported by the spring guide 82, the spring 42 does not bend inside the outer pipe 74 and is kept coaxial with the reference axis J. The spring guide 82 advances and retreats integrally with the advancing / retreating pipe 72. The base end portion 82a of the spring guide 82 has a tapered shape so as not to hit the spring 42. The spring guide 82 is provided with a plurality of through holes 82b (see FIG. 20) in the axial direction for weight reduction.

The shaft 32 protrudes further to the tip side than the base end pipe 20, and at least a part of the shaft 32 protrudes to the inside of the advancing / retreating pipe 72. The power transmission unit 80 is arranged in the lumen portion of the advancing / retreating pipe 72 in a state of being fitted to the shaft 32.

FIG. 17 is a perspective view showing the tip end portion of the expansion / contraction mechanism 10B. As shown in FIG. 17, the tip end portion 18 includes a swing shaft member 18a, a cap 18b, a joint 18c, and a member 18d. The joint 18c is a member fixed to the outer pipe 74 by the caulking portion 74a, and the tip portion of the advancing / retreating pipe 72 is inserted into the inner hole. The tip end portion of the advancing / retreating pipe 72 is fixed to the base end portion 18ab of the swing shaft member 18a by caulking or the like. A part of the periphery of the swing shaft member 18a forms a flat portion 18aa. A part of the inner peripheral portion of the joint 18c forms a flat portion 18ca. The flat portion 18aa and the flat portion 18ca are in contact with each other, and the so-called D-cut shape engagement has an anti-rotation effect. The cap 18b covers the outer peripheral portion of the joint 18c or the like.

The swing shaft member 18a is a portion that is swingably connected to the main body of the vehicle 12 (see FIG. 1) and does not rotate around the reference axis J. Therefore, the advancing / retreating pipe 72 also does not rotate around the reference axis J. Similarly, since the motor 28 and the proximal pipe 20 are connected to the tailgate 14 by the proximal end portion 16, they do not rotate around the reference axis J. Since the tailgate 14 is openably and closably connected to the main body of the vehicle 12 by a hinge 14a (see FIG. 1), the vehicle 12 and the tailgate 14 eventually form a link mechanism and the advancing / retreating pipe 72 with respect to the motor 28. Functions as a base body that is non-rotatable and can move forward and backward along the reference axis J. Further, although the outer pipe 74 is not provided with the protrusion 24a (see FIG. 3) in the first pipe 24 of the expansion / contraction mechanism 10A, the joint 18c is used to prevent the swing shaft member 18a from rotating, so that the reference axis It does not rotate around J.

18A and 18B are perspective views of the internal mechanism of the telescopic mechanism 10B, FIG. 18A is a perspective view showing a stretched state, and FIG. 18B is a perspective view showing a contracted state. Although the base end pipe 20 and the spring guide 82 are omitted in FIG. 18, the outer pipe 74 is shown by a virtual line. Further, in FIG. 18A, the spring 42 is omitted, and in FIG. 18B, the advancing / retreating pipe 72 is omitted.

The base end portion of the spring 42 is supported by the spring receiving seat 40, and the tip end portion is supported by the tip end portion 18. Although the spring 42 is omitted in FIG. 18A, it has a natural length or a slightly compressed state when the expansion / contraction mechanism 10B is extended, and as shown in FIG. 18B, the expansion / contraction mechanism 10B In the contracted state, it is considerably compressed. The spring 42 is elastically biased in a direction in which the shaft 32 and the advancing / retreating pipe 72 are separated from each other along the reference axis J.

FIG. 19 is an exploded perspective view showing the power transmission unit 80 and its related members. FIG. 20 is a cross-sectional view of the power transmission unit 80 and its related members as viewed from the direction of the reference axis J. As shown in FIGS. 19 and 20, the power transmission unit 80 includes a case 84, a roller holder 86, and a plurality of rollers 88. In this case, the number of rollers 88 is three. Although the roller 88 is a cylindrical body, it may have a shape like the roller 46 in FIG. 11 (a) or the roller 46A in FIG. 11 (b).

The roller holder 86 has a substantially cylindrical shape, and includes a central hole 86a through which the shaft 32 is inserted, three roller storage portions 86b, and flanges 86c provided at both ends in the axial direction. Each of the roller storage portions 86b is a portion in which the rollers 88 are fitted and stored. The inner surface of the roller storage portion 86b is a columnar recess whose inner surface is matched to the outer peripheral shape of the roller 88, and the roller 88 can roll inside the roller storage portion 86b. That is, the roller holder 86 rotatably holds the plurality of rollers 88. The inner surface of the roller housing portion 86b may be provided with a low friction material so that the roller 88 rotates smoothly.

The roller storage portion 86b is open to the central hole 86a, and the roller 88 slightly protrudes from this opening into the center hole 86a. The portion of the roller 88 protruding from the center hole 86a comes into contact with the outer peripheral surface of the shaft 32. The rollers 88 and the roller storage portions 86b are provided in the roller holder 86 at equal intervals (120 °) in the circumferential direction. The two flanges 86c have flat sides in the shape of a regular triangle.

FIG. 21 is a side view of the shaft 32, the roller holder 86, and the roller 88. As shown in FIG. 21, the roller storage portion 86b is formed so that the central axis of the stored roller 88 is tilted by an inclination angle θ with respect to the reference axis J. The inclination angle θ of the roller 88 has the same effect as the inclination angle θ of the roller 46 (see FIG. 8).

Returning to FIGS. 19 and 20, the case 84 is a member in which the roller holder 86 is stored. The case 84 has a substantially cylindrical shape, and includes three flat surfaces 84a formed on the inner peripheral portion and a hexagonal flange 84b provided on the tip portion. The three flat surfaces 84a abut on the flat side of the flange 86c of the roller holder 86 and serve as a detent around the roller holder 86. The case 84 is fixed to the hexagonal cylinder 90 at the base end of the advancing / retreating pipe 72.

The hexagonal cylinder 90 is a part where the case 84 is inserted and fixed, and the inner circumference and the outer circumference are hexagonal due to press working or the like. Each side of the hexagonal flange 84b of the case 84 abuts on the hexagonal surface of the inner circumference of the hexagonal cylinder 90 to prevent rotation.

FIG. 22 is a side sectional view showing the power transmission unit 80 and its related members. As shown in FIG. 22, the case 84 is also fixed in the axial direction by the hexagonal cylinder 90. Of these, the tip side is displacement-regulated by a diameter-reduced portion 92 formed at the tip of the hexagonal cylinder 90. The tip portion 32a of the shaft 32 projects toward the tip end side of the diameter reduction portion 92. The tip portion 32a is a male screw, and the flange nut 94 is screwed into the tip portion 32a. Displacement of the shaft 32 toward the proximal end side is restricted by the flange nut 94 coming into contact with the reduced diameter portion 92. The outer diameter of the flange nut 94 is slightly smaller than the inner diameter of the advancing / retreating pipe 72, and the flange nut 94 and the shaft 32 can be displaced toward the tip side along the reference axis J.

As described above, the expansion / contraction mechanism 10B is integrally provided with the shaft 32 and the advancing / retreating pipe 72 coaxially provided with respect to the reference axis J, the rollers 88 provided in the lumen portion of the advancing / retreating pipe 72, and the shaft 32. A roller holder 86 that rotates and holds a plurality of rollers 88 rotatably is provided. Each of the plurality of rollers 88 is in contact with the outer peripheral surface of the shaft 32, and is held by the roller holder 86 so that the central axis has an inclination angle θ with respect to the reference axis J. Further, since the advancing / retreating pipe 72 is connected to the tailgate 14 via the tip end portion 18, it cannot rotate, and the link mechanism based on the hinge 14a allows the advancing / retreating pipe 72 to freely advance / retreat along the reference axis J. In the expansion / contraction mechanism 10B, the motor 28 rotates the shaft 32 via the speed reducer 30 in such a configuration, so that the plurality of rollers 88 are revolving relative to the shaft 32 about the reference axis J, respectively. As it rotates, it rotates in the roller housing portion 86b. Since the rollers 88 are arranged so as to have an inclination angle θ with respect to the reference axis J, the roller 88 rotates (revolves and rotates), so that the advance / retreat pipe 22 has an axial direction according to the inclination angle θ. Is added, and it is possible to move forward and backward along the reference axis J.

FIG. 23-1 is a schematic cross-sectional side view of the expansion / contraction mechanism 10C according to the third embodiment. FIG. 23-2 is a schematic cross-sectional side view of the expansion / contraction mechanism 10D according to the fourth embodiment. FIG. 23-3 is a schematic cross-sectional side view of the expansion / contraction mechanism 10E according to the fifth embodiment.

(Third Embodiment)
As shown in FIG. 23-1, the expansion / contraction mechanism 10C according to the third embodiment is provided with a shaft 32A instead of the shaft 32 in the expansion / contraction mechanism 10A. The outer diameter of the shaft 32 is constant along the reference axis J, whereas the outer diameter of the shaft 32A changes along the reference axis J. In this case, the outer diameter D1 near the proximal end side is smaller than the outer diameter D2 near the distal end side, and the outer diameter D1 changes in a tapered shape along the reference axis J. As a result, when the telescopic mechanism 10C expands from the contracted state, the pressing force between the roller 46 and the outer peripheral surface of the shaft 32A becomes large, and the propulsive force converted from the rotation of the shaft 32 is more reliably advanced and retreated. It will be transmitted to 22. That is, since the outer diameter of the shaft 32A changes along the reference axis J, the transmission torque can be changed according to the amount of advance / retreat. Depending on the design conditions, D1> D2 may be set, or the outer diameter may increase or decrease along the reference axis J.

(Fourth Embodiment)
As shown in FIG. 23-2, in the expansion / contraction mechanism 10D according to the fourth embodiment, the motor 28 rotates the advancing / retreating pipe 22 not through the shaft 32 but through the rotating shaft 60, and the shaft 32 passes through the member 62. It is fixed to the base end pipe 20. A power transmission unit 36 is fitted at the tip of the shaft 32. A protrusion 64a of the base body 64 is fitted in the groove 20a of the base end pipe 20, and the base end pipe 20 is non-rotatable and can move forward and backward. The base body 64 fixes the motor 28 and the speed reducer 30.

In such an expansion / contraction mechanism 10D, the shaft 32 rotates relative to the power transmission unit 36 due to the rotation of the motor 28, power is transmitted to and from the power transmission unit 36 to generate thrust, and the base end. The pipe 20 can be moved forward and backward.

That is, as is clear from comparing the expansion / contraction mechanism 10D and the expansion / contraction mechanism 10A, the shaft 32 and the power transmission unit 36 are relatively relative to each other in order to advance / retreat the advancing / retreating pipe 22 with respect to the base end pipe 20. If it rotates, a propulsive force is generated, and it is sufficient that one is on the rotating side and the other is on the fixed side. Therefore, the motor 28 rotates one of the shaft 32 and the advancing / retreating pipe 22, and the base end pipe 20 or the base body 64 holds the other of the shaft 32 and the advancing / retreating pipe 22 non-rotatably and freely advancing / retreating along the reference axis J. You just have to do it.

(Fifth Embodiment)
As shown in FIG. 23-3, the expansion / contraction mechanism 10E according to the fifth embodiment includes the base end pipe 20 and the advancing / retreating pipe 22 in the above-mentioned expansion / contraction mechanism 10A, but the base end pipe 20 has a groove 20a. The advancing / retreating pipe 22 does not have a protrusion 24a that engages with the groove 20a. Such a telescopic mechanism 10E forms a triangular link mechanism together with the main body and the tailgate 14 of the vehicle 12 in the same manner as the telescopic mechanism 10B described above. After all, the vehicle 12 and the tailgate 14 function as a base body that holds the advancing / retreating pipe 22 with respect to the motor 28 so as to be non-rotatable and advancing / retreating along the reference axis J. Therefore, the advancing / retreating pipe 22 does not rotate around the reference axis J, and can advance / retreat with respect to the base end pipe 20 by receiving the power of the motor 28 from the power transmission unit 36.

The present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be freely changed without departing from the gist of the present invention.

10, 10A, 10B, 10C, 10D, 10E Telescopic mechanism 16 Base end end 18 Tip end (tip spring receiving part)
20 Base end pipe (base body)
22,72 Advance / retreat pipe 28 motor (drive source)
32, 32A Shaft 34 1st bearing 36,80 Power transmission unit 38 2nd bearing 40 Spring bearing (base end spring receiving part)
42

Spring

44,86

Roller holder

46,46A, 88 Roller 48 Roller shaft 50bb, 52bb Spring (pressing means)
64 Base body 82 Spring guide (support cylinder)
J reference axis θ tilt angle

Claims

Shafts and advancing / retreating pipes provided coaxially with the reference axis,
A drive source that rotates one of the shaft and the advancing / retreating pipe,
A base body that holds the other non-rotatably and can move forward and backward along the reference axis.
A plurality of rollers provided in the lumen of the advancing / retreating pipe and
A roller holder that rotates integrally with the advancing / retreating pipe and rotatably holds a plurality of the rollers.
With
The expansion / contraction mechanism, wherein each of the plurality of rollers is in contact with the outer peripheral surface of the shaft and is held by the roller holder so that the central axis has an inclination angle with respect to the reference axis.
The expansion / contraction mechanism according to claim 1, wherein at least one of the outer peripheral surface of the roller and the outer peripheral surface of the shaft is an elastic body.
The expansion / contraction mechanism according to claim 1 or 2, wherein at least one surface of the outer peripheral surface of the roller and the outer peripheral surface of the shaft is subjected to a non-slip treatment.
The expansion / contraction mechanism according to any one of claims 1 to 3, wherein the roller holder includes a pressing means for elastically pressing a plurality of the rollers against the outer peripheral surface of the shaft.
Any of claims 1 to 4, wherein the roller has an axial length larger than the maximum diameter, a central portion having a maximum diameter portion, and a shape having a small diameter toward both sides along the axial direction. The expansion and contraction mechanism according to item 1.
The plurality of rollers are arranged in parallel at equal intervals along the circumferential direction about the reference axis, and adjacent rollers are provided so as to overlap each other in the direction along the reference axis. The expansion / contraction mechanism according to any one of claims 1 to 5.
Equipped with a base end end that is swingably connected to the tailgate of the vehicle at one end
The expansion / contraction mechanism according to any one of claims 1 to 6, further comprising a tip end portion oscillatingly connected to the main body of the vehicle at the other end.
The expansion / contraction mechanism according to any one of claims 1 to 7, wherein the shaft has an inner diameter that changes along the reference axis.
The expansion / contraction mechanism according to any one of claims 1 to 8, further comprising a spring that elastically biases the shaft and the advance / retreat pipe in a direction in which they are separated from each other along the reference axis.
The expansion / contraction mechanism according to claim 9, wherein a support cylinder for supporting the spring from the inner surface is provided between the advancing / retreating pipe and the spring.
A method for manufacturing a telescopic mechanism according to claim 9 or 10, wherein the telescopic mechanism is manufactured.
A step of fixing a power transmission unit having a plurality of the rollers mounted on the roller holder to the shaft, and
A step of providing a base end spring receiving portion for supporting the base end portion of the spring on the base end side of the advancing / retreating pipe, and a step of providing the base end spring receiving portion.
A step of covering the power transmission unit with the base end side of the advancing / retreating pipe provided with the base end spring receiving portion, and
The process of inserting the spring into the inside from the tip side of the advancing / retreating pipe, and
A step of fixing a tip spring receiving portion that supports the tip portion of the spring to the tip of the advancing / retreating pipe into which the spring is inserted, and a step of fixing the tip spring receiving portion.
A method for manufacturing an expansion / contraction mechanism, which comprises.