JP2018100743A - Tripod-type constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the rotation torque of a roller unit, and to improve an NVH characteristic.SOLUTION: A tripod-type constant velocity universal joint is composed of: an outside joint member in which three track grooves extending to an axial direction are formed at an internal peripheral face, and roller guide faces mutually opposing inside walls of the track grooves are formed; a tripod member having three leg shafts extending to a radial direction; and a roller unit 30 which is rotatably supported to the leg shafts of the tripod members, rollingly inserted into the track grooves of the outside joint members, and guided along the roller guide faces. The roller unit 30 comprises: an outer roller 31 contacting with the roller guide faces; an inner roller 32 externally fit to the leg shafts at the inside of the outer roller 31; a plurality of needle rollers 33 interposed between the outer roller 31 and the inner roller 32; and a come-off prevention snap ring 36 fit to an annular recessed groove 34 of an internal peripheral face of the outer roller. Implanting parts 60a, 60b on which fiber are implanted are formed at outer surfaces 36a, 36b of the snap ring 36.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a tripod type constant velocity universal joint that is used in a power transmission system of an automobile or various industrial machines, and is particularly incorporated in a drive shaft or propeller shaft for an automobile.

  There are two types of constant velocity universal joints incorporated in drive shafts and propeller shafts that transmit rotational force from the engine of an automobile to wheels at a constant speed: fixed constant velocity universal joints and sliding constant velocity universal joints. Both of these constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected so that rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle.

  The drive shaft needs to cope with angular displacement and axial displacement due to a change in the relative positional relationship between the engine and the wheels. Therefore, the drive shaft is generally equipped with a sliding type constant velocity universal joint on the engine side (inboard side) and a fixed type constant velocity universal joint on the wheel side (outboard side). It has a structure in which universal joints are connected by a shaft.

  One of the sliding type constant velocity universal joints assembled to the drive shaft is a tripod type constant velocity universal joint using a roller as a torque transmission member (see, for example, Patent Document 1).

  This tripod type constant velocity universal joint is composed of an outer joint member, a tripod member, and a roller unit, and the inner part composed of the tripod member and the roller unit is accommodated in the outer joint member so as to be slidable in the axial direction. The structure is provided.

  In the outer joint member, three track grooves extending in the axial direction are formed on the inner peripheral surface thereof, and roller guide surfaces facing each other are formed on the inner side wall of each track groove. The tripod member has three leg shafts protruding in the radial direction. The roller unit is rotatably supported by the leg shaft of the tripod member, and is rotatably inserted into the track groove of the outer joint member and guided along the roller guide surface.

  The roller unit includes an outer roller that contacts the roller guide surface, an inner roller that is externally fitted to the leg shaft inside the outer roller, a needle roller that is interposed between the outer roller and the inner roller, and an annular concave groove on the outer peripheral surface of the outer roller. The inner ring and the retaining ring that prevents the needle roller from coming off are fitted.

  In this tripod type constant velocity universal joint, a lubricant such as grease is sealed in the inner space of the outer joint member, so that the sliding part inside the joint during operation of the joint, that is, the outer joint member, the tripod member, and the roller unit. The lubricity at the sliding part is ensured.

  The tripod type constant velocity universal joint extends in the axial direction from the opening of the outer joint member and the tripod member in order to prevent leakage of the lubricant enclosed in the joint and to prevent foreign matter from entering from the outside of the joint. A structure in which a boot made of resin or rubber is mounted between the shaft and the shaft.

  In the tripod type constant velocity universal joint configured as described above, the leg shaft of the tripod member and the roller guide surface of the outer joint member are engaged with each other in the rotational direction of the two shafts via the roller unit, so that the driven side is driven. Rotational torque is transmitted at a constant speed. Further, the roller unit rolls on the roller guide surface while rotating with respect to the leg shaft, thereby allowing relative axial displacement and angular displacement between the outer joint member and the tripod member.

Japanese Patent No. 4118547

  By the way, in the tripod type constant velocity universal joint disclosed in Patent Document 1, the outer roller, the needle roller and the inner roller roll relatively smoothly in the roller unit when the joint is operated. Noise Vibration Harshness) characteristics are secured.

  Here, the roller unit in the aforementioned tripod type constant velocity universal joint has a structure in which the inner roller and the needle roller are prevented from coming off from the outer roller by a retaining ring fitted in an annular groove on the inner peripheral surface of the outer roller. Yes.

  Since such a structure is adopted, the retaining ring is relatively slipped between the contact parts including the outer roller, the inner roller, and the needle roller, so that the rotational torque of the roller unit tends to increase. Due to the increase in the rotational torque, the NVH characteristics may be degraded.

  Accordingly, the present invention has been proposed in view of the above-described improvements, and its object is to provide a tripod type constant velocity universal joint that can reduce the rotational torque of the roller unit and improve the NVH characteristics. There is to do.

  The tripod type constant velocity universal joint according to the present invention is an outer joint member in which three track grooves extending in the axial direction are formed on the inner peripheral surface and roller guide surfaces facing each other are formed on the inner side wall of each track groove. And a tripod member having three leg shafts projecting in the radial direction, and rotatably supported by the leg shaft of the tripod member and rotatably inserted in the track groove of the outer joint member along the roller guide surface The basic structure which consists of a roller unit guided in this way is provided.

  The roller unit in the tripod type constant velocity universal joint includes an outer roller that contacts the roller guide surface, an inner roller that is fitted on the leg shaft inside the outer roller, and a plurality of needle rollers that are interposed between the outer roller and the inner roller. And a retaining ring that is fitted into an annular groove on the inner peripheral surface of the outer roller and prevents the inner roller and the needle roller from coming off.

  As technical means for achieving the above-mentioned object, the tripod type constant velocity universal joint according to the present invention is characterized in that a flocked portion in which fibers are implanted is formed on the outer surface of a retaining ring.

  In the present invention, since the flocked portion is formed on the outer surface of the retaining ring of the roller unit, the lubricant from inside and outside the roller unit is held by the flocked portion when the joint is operated. From this, it is possible to reduce the rotational torque of the roller unit resulting from the sliding of the retaining ring relatively between the contact parts including the outer roller, the needle roller, and the inner roller.

  The flocked portion in the present invention preferably has a structure formed on the outer surface in the radial direction of a retaining ring that is fitted into an annular groove on the inner peripheral surface of the outer roller with a snug fit.

  In this way, in the case of a structure in which the retaining ring is fitted into the annular concave groove on the inner peripheral surface of the outer roller by an interference fit, the rotational torque of the roller unit can be reduced by forming a flocked portion on the radially outer surface of the retaining ring. It becomes easy.

  The flocked portion in the present invention preferably has a structure formed on a radially outer surface and a circumferential outer surface of a retaining ring fitted by a clearance fit in an annular groove on the inner circumferential surface of the outer roller.

  In this way, in the case of a structure in which the retaining ring is fitted to the annular concave groove on the inner peripheral surface of the outer roller with a clearance fit, if the flocking portion is formed on the radial outer surface and the circumferential outer surface of the retaining ring, the roller unit It becomes easy to reduce rotational torque.

  The flocked portion in the present invention preferably has a structure in which short fibers are implanted in a state perpendicular to the outer surface of the retaining ring. This structure can be realized by electrostatic flocking.

  If such a structure is adopted, a large amount of short fibers can be densely implanted in a short time on the outer surface of the retaining ring.

  The flocked portion in the present invention preferably has a structure in which short fibers are implanted in a state inclined at a constant angle with respect to the outer surface of the retaining ring. This structure can be realized by electrostatic spraying.

  If such a structure is employ | adopted, a large area can be covered with a small amount of short fiber by reducing the flocking density compared with the electrostatic flocking which is not sprayed. As a result, the amount of lubricant retained on the flocks increases, and the rotational torque can be reduced more effectively.

  According to the present invention, by forming the flocked portion on the outer surface of the retaining ring of the roller unit, the lubricant from inside and outside the roller unit is held by the flocked portion when the joint is operated. From this, it is possible to reduce the rotational torque of the roller unit resulting from the sliding of the retaining ring relatively between the contact parts including the outer roller, the needle roller, and the inner roller. By reducing the rotational torque, the NVH characteristics can be improved.

1 is a longitudinal sectional view showing an overall configuration of a tripod type constant velocity universal joint in an embodiment of the present invention. It is sectional drawing which follows the PP line | wire of FIG. It is a cross-sectional view which shows the leg shaft and roller unit of FIG. It is a partial expanded sectional view which shows the structural example of the roller unit of FIG. It is a partial expanded sectional view which shows the other structural example of the roller unit of FIG. It is a block diagram for demonstrating the outline point of electrostatic flocking. (A) is an expanded sectional view of the flocked part formed by electrostatic flocking, (B) is an expanded sectional view of the flocked part formed by electrostatic spraying flocking.

  Embodiments of a tripod type constant velocity universal joint according to the present invention will be described below in detail with reference to the drawings. In the following embodiments, a double roller type tripod type constant velocity universal joint (hereinafter simply referred to as a constant velocity universal joint) capable of reducing vibration during operation will be exemplified.

  1 to 3 show a basic configuration of a constant velocity universal joint, FIG. 1 is a longitudinal sectional view with respect to the axis of the joint, and FIG. 2 is a sectional view taken along the line P-P in FIG. 1 (however, only one roller unit 30 is shown). 3 is a cross-sectional view of the leg shaft 22 and the roller unit 30 of FIG. Before describing the characteristic configuration of this embodiment, the overall configuration of the constant velocity universal joint will be described.

  In the constant velocity universal joint of this embodiment, the outer joint member 10, the tripod member 20, and the roller unit 30 are the main parts, and the inner part composed of the tripod member 20 and the roller unit 30 is pivoted to the outer joint member 10. It has a structure that is slidable in the direction.

  The outer joint member 10 has a cup shape having an opening 11 at one end, and a shaft 12 is integrally provided at the center of the bottom. Three linear track grooves 13 extending in the axial direction are formed on the inner peripheral surface of the outer joint member 10 at equal intervals in the circumferential direction. Each track groove 13 has a pair of roller guide surfaces 14 facing each other on both inner walls thereof. The roller guide surface 14 has an arc-shaped cross section and extends linearly in the axial direction of the outer joint member 10.

  The tripod member 20 has three leg shafts 22 integrally formed radially at equal intervals in the circumferential direction (120 ° intervals) on the outer peripheral surface of a cylindrical boss 21. The tip of the leg shaft 22 extends in the radial direction to the vicinity of the bottom of the track groove 13. The shaft end of the shaft 40 is connected to the shaft hole of the boss 21 by spline fitting. The shaft 40 is prevented from coming off from the tripod member 20 by an annular retaining ring 41.

  The roller unit 30 includes an outer roller 31 that contacts the roller guide surface 14, an inner roller 32 that is externally fitted to the leg shaft 22 inside the outer roller 31, and a plurality of needle rollers 33 that are interposed between the outer roller 31 and the inner roller 32. And. The roller unit 30 is rotatably supported by the leg shaft 22 of the tripod member 20, and is rotatably inserted into the track groove 13 of the outer joint member 10 and guided along the roller guide surface 14.

  The inner roller 32 and the needle roller 33 are formed on the inner side in the radial direction of the inner peripheral surface of the outer roller 31 and the retaining ring 36 fitted in the annular groove 34 formed on the outer side in the radial direction of the inner peripheral surface of the outer roller 31. The outer roller 31 is prevented from coming off by a retaining ring 37 fitted in the annular groove 35.

  The outer peripheral surface of the outer roller 30 has an arcuate longitudinal section, and may contact the roller guide surface 14 at two locations by angular contact or contact at one location by circular contact. On the other hand, the inner peripheral surface of the inner roller 32 has a convex arc shape. A plurality of needle rollers 33 are disposed between the outer roller 31 and the inner roller 32 in a so-called single row full roller state without a cage.

  The leg shaft 22 has a straight shape perpendicular to the joint axis in the longitudinal section, contacts the inner peripheral surface of the inner roller 32 in the direction perpendicular to the joint axis in the transverse section, and the inner roller 32 in the joint axial direction. A gap n is formed between the inner peripheral surface and the inner peripheral surface.

  In this constant velocity universal joint, the leg shaft 22 of the tripod member 20 and the roller guide surface 14 of the outer joint member 10 are engaged with each other in the biaxial rotation direction via the roller unit 30, so that the drive side is moved to the driven side. Rotational torque is transmitted at a constant speed.

  Further, the roller unit 30 rolls on the roller guide surface 14 while rotating with respect to the leg shaft 22, thereby allowing relative axial displacement and angular displacement between the outer joint member 10 and the tripod member 20. Is done.

  At this time, a gap n is formed between the leg shaft 22 and the inner roller 32 in the axial direction of the joint, and the leg shaft 22 is tiltable with respect to the roller unit 30 that rolls on the roller guide surface 14. Therefore, even if the joint takes an operating angle, the roller unit 30 does not tilt with respect to the roller guide surface 14.

  In this way, the roller unit 30 and the roller guide surface 14 are prevented from being obliquely crossed with the inclination of the leg shaft 22, thereby reducing induced thrust and slide resistance.

  In this constant velocity universal joint, a lubricant such as grease (not shown) is sealed in the inner space of the outer joint member 10, so that the sliding part inside the joint, that is, the outer joint member 10, The lubricity at the sliding part in the tripod member 20 and the roller unit 30 is ensured.

  Further, in order to prevent leakage of the lubricant sealed inside the joint and to prevent foreign matter from entering from the outside of the joint, it is provided between the opening 11 of the outer joint member 10 and the shaft 40 extending in the axial direction from the tripod member 20. A bellows-like boot 50 made of resin or rubber is attached. The boot 50 closes the opening 11 of the outer joint member 10.

  The overall configuration of the constant velocity universal joint in this embodiment is as described above. The characteristic configuration of the constant velocity universal joint in this embodiment will be described in detail below.

  As shown in FIG. 4, the flocked portions 60a and 60b (shaded portions in the figure) in which a large number of fibers are implanted on the outer surface 36a and the inner surface 36b, which are the radially outer surfaces of the retaining ring 36 of the roller unit 30. ). Although the needle roller 33 and the inner roller 32 slide relative to the retaining ring 36, the flocked portions 60a and 60b are interposed between the sliding surfaces.

  Thus, by forming the hair transplant portions 60a and 60b on the outer surface 36a and the inner surface 36b of the retaining ring 36, the lubricant from inside and outside the roller unit 30 adheres to and is held on the hair transplant portions 60a and 60b.

  Since the lubricant is held by the flocked portions 60a and 60b, the sliding resistance generated between the sliding surfaces of the needle roller 33 and the inner roller 32 with respect to the retaining ring 36 is reduced. Due to the reduction of the slip resistance, the rotational torque of the roller unit 30 is reduced as compared with the case where the flocked portions 60a and 60b are not provided. By reducing the rotational torque, the NVH characteristics can be improved.

  In the embodiment shown in FIG. 4, a structure in which the retaining ring 36 is fitted into the annular groove 34 on the inner peripheral surface of the outer roller 31 by an interference fit is illustrated. When the retaining ring 36 has a tight fitting structure as in this embodiment, as described above, the flocked portions 60a and 60b are formed on the outer surface 36a and the inner surface 36b of the retaining ring 36.

  On the other hand, the embodiment shown in FIG. 5 illustrates a structure in which the retaining ring 36 is fitted into the annular groove 34 on the inner peripheral surface of the outer roller 31 by a clearance fit. When the retaining ring 36 has a clearance fitting structure as in this embodiment, the flocked portions 60a and 60b are formed on the outer surface 36a and the inner surface 36b of the retaining ring 36, and the outer circumferential surface 36c that is the circumferential outer surface is formed. However, it is effective to form a flocked portion 60c (shaded portion in the figure) in which a large number of fibers are implanted.

  In this case, the retaining ring 36 rotates together with the outer roller 31, but the flocked portion 60 c is interposed between the annular concave groove 34 of the outer roller 31 and the outer peripheral surface 36 c of the retaining ring 36. As described above, the needle roller 33 and the inner roller 32 slide relative to the retaining ring 36, and the flocked portions 60a and 60b are interposed between the sliding surfaces.

  Thus, by forming the flocked portions 60a to 60c on the outer surface 36a and inner surface 36b and the outer peripheral surface 36c of the retaining ring 36, the lubricant from inside and outside the roller unit 30 adheres to the flocked portions 60a to 60c and is held. Is done.

  Since the lubricant is held by the flocked portion 60c, the friction torque due to the stirring resistance and shearing resistance of the lubricant accompanying the rotation of the retaining ring 36 is reduced as compared with the case where there is no flocked portion 60c. Further, since the lubricant is held by the flocked portions 60a and 60b, the sliding resistance generated between the sliding surfaces of the needle roller 33 and the inner roller 32 with respect to the retaining ring 36 is reduced. Due to the reduction of the slip resistance, the rotational torque of the roller unit 30 is reduced as compared with the case where the flocked portions 60a and 60b are not provided. The NVH characteristics can be improved by reducing the friction torque and the rotational torque.

  The flocked portions 60a to 60c are formed by implanting short fibers on the outer surface 36a and the inner surface 36b or the outer peripheral surface 36c of the retaining ring 36. As the flocking method, electrostatic flocking or electrostatic spraying flocking can be employed. These methods are preferable in that a large amount of fibers can be densely planted in a short time not only on the outer surface 36a and the inner surface 36b of the retaining ring 36 but also on a curved surface portion such as the outer peripheral surface 36c.

  Electrostatic flocking includes an adhesive application process, an electrostatic flocking process, a drying process, a finishing process, and the like. The electrostatic flocking process is shown in FIG. In electrostatic flocking, an adhesive layer 70 is formed by applying an adhesive on the outer surface (represented as a flat surface for convenience) of a retaining ring 36 that is a flocking object, and an electrostatic field is created by a high-voltage electrode 72, The short fibers 71 are raised on the adhesive layer 70 with a suction force, and then a drying process for drying the adhesive of the adhesive layer 70 is performed, and then a finishing process for removing hair is performed.

  In the electrostatic flocking process, short fibers 71 cut to a predetermined size (the surface of which an electrolyte or surfactant film is formed, that is, the electrodeposition treatment agent is coated) are placed in the vicinity of the high voltage electrode 72. To do. With this input, the short fiber 71 is attracted to the high voltage electrode 72 by Coulomb force. For this reason, the short fiber 71 is charged to the same potential as the electrode at the moment when it touches the high voltage electrode 72 and is repelled by Coulomb force. Since the repelled short fibers 71 are given a high potential, they fly toward the ground side. At this time, since the adhesive layer 70 is formed on the outer surface of the retaining ring 36 on the ground side, the short fibers 71 are pierced into the adhesive layer 70. In this way, the short fibers 71 are planted on the outer surface of the retaining ring 36, and the flocked portions 60 a to 60 c are formed on the outer surface of the retaining ring 36.

  FIG. 7A illustrates the flocked portions 60a to 60c formed by electrostatic flocking. Moreover, FIG.7 (B) illustrates the flocked part 60a-60c formed by electrostatic spraying flocking. In the figure, the outer surface 36a and the inner surface 36b of the outer surface of the retaining ring 36, which is the object to be implanted, are flat surfaces, whereas the outer peripheral surface 36c is a curved surface. Expressed as a surface.

  In electrostatic flocking, as shown in FIG. 7 (A), the short fibers 71 are planted in a state perpendicular to the outer surface of the retaining ring 36. On the other hand, as shown in FIG. 7B, the electrostatic spraying flocking is based on substantially the same principle as the electrostatic flocking without spraying. Unlike electrostatic flocking, the short fibers 71 are planted in an inclined state with respect to the outer surface of the retaining ring 36 by spraying the short fibers 71 on the adhesive application surface with air. The

  For this reason, according to electrostatic spraying flocking, a large area can be covered with a small amount of short fibers 71 by reducing the flocking density compared to electrostatic flocking that is not sprayed. In particular, the amount of lubricant retained on the flocks increases, and the rotational torque can be reduced more effectively.

  The short fiber 71 used for flocking is not particularly limited as long as it can be used as a short fiber for flocking. For example, (1) polyolefin resin such as polyethylene and polypropylene, polyamide resin such as nylon, aromatic polyamide resin, polyethylene Polyester resin such as terephthalate, polyethylene naphthalate, polyethylene succinate, polybutylene terephthalate, synthetic resin fiber such as acrylic resin, vinyl chloride, vinylon, (2) inorganic fiber such as carbon fiber, glass fiber, (3) rayon, acetate And natural fibers such as cotton, silk, hemp and wool.

  These may be used alone or in combination of two or more. Among the above-mentioned (1) to (3), since lubrication and dissolution with oil are difficult to occur and chemically stable, homogeneous fibers can be produced in large quantities, and can be obtained at low cost. It is preferable to use a synthetic resin fiber.

  The shape of the short fiber 71 is not particularly limited as long as it does not interfere with other members that adversely affect the retaining function of the retaining ring 36 at the locations where the flocked portions 60a to 60c are formed. As a specific shape, for example, those having a length of 0.5 to 2.0 mm and a thickness of 0.5 to 50 dtex are preferable, and the density of the short fibers 71 of the flocked portions 60a to 60c is as follows. The proportion of fibers is preferably 10 to 30%.

  As the shape of the short fiber 71, there are straight and bend (a shape where the tip is bent), and the cross-sectional shape is circular or polygonal. The bend shape can hold the lubricant more strongly than the straight shape. By using the short fibers 71 having a polygonal cross section, the surface area can be made larger than that of the short fibers 71 having a circular cross section, and the surface tension of the lubricant can be increased. It is preferable to select the shape of the short fiber 71 according to each characteristic.

  Examples of the adhesive layer 70 include an adhesive mainly composed of urethane resin, epoxy resin, acrylic resin, vinyl acetate resin, polyimide resin, silicone resin, and the like. For example, urethane resin solvent adhesive, epoxy resin solvent adhesive, vinyl acetate resin solvent adhesive, acrylic resin emulsion adhesive, acrylate-vinyl acetate copolymer emulsion adhesive, vinyl acetate emulsion adhesive , Urethane resin emulsion adhesive, epoxy resin emulsion adhesive, polyester emulsion adhesive, ethylene-vinyl acetate copolymer adhesive and the like. These may be used independently and 2 or more types may be used together.

  In the above embodiment, as shown in FIGS. 4 and 5, the retaining ring 36 fitted to the annular groove 34 formed on the radially outer side of the inner peripheral surface of the outer roller 31 has been described. However, the present invention is not limited to this, and the retaining ring 37 fitted in the annular concave groove 35 formed on the radially inner side of the inner peripheral surface of the outer roller 31 can also form a flocked portion in the same manner as the retaining ring 36. It is an effective means. About the structure and effect of the hair transplant part formed in the retaining ring 37, since it is the same as that of the case of the retaining ring 36, the duplication description is abbreviate | omitted.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 10 Outer joint member 13 Track groove 14 Roller guide surface 20 Tripod member 22 Leg shaft 30 Roller unit 31 Outer roller 32 Inner roller 33 Needle roller 34, 35 Annular groove 36, 37 Retaining ring 36a-36c Outer surface 60a-60c

Claims (5)

An outer joint member in which three track grooves extending in the axial direction are formed on the inner peripheral surface and roller guide surfaces facing each other are formed on the inner wall of each track groove, and three leg shafts projecting in the radial direction And a roller unit that is rotatably supported by the leg shaft and is rotatably inserted into the track groove and guided along the roller guide surface.
The roller unit includes an outer roller that contacts the roller guide surface, an inner roller that is externally fitted to the leg shaft inside the outer roller, a plurality of needle rollers that are interposed between the outer roller and the inner roller, and an outer peripheral surface of the outer roller A tripod type constant velocity universal joint, comprising: a retaining ring for retaining which is fitted in the annular concave groove; and a flocked portion in which fibers are implanted on the outer surface of the retaining ring.   2. The tripod type constant velocity universal joint according to claim 1, wherein the flocked portion is formed on a radially outer surface of a retaining ring fitted into the annular concave groove by an interference fit.   The tripod type constant velocity universal joint according to claim 1, wherein the flocked portion is formed on a radially outer surface and a circumferential outer surface of a retaining ring that is fitted in the annular concave groove by a clearance fit.   The tripod type constant velocity universal joint according to any one of claims 1 to 3, wherein a short fiber is planted in a state perpendicular to the outer surface of the retaining ring.   The tripod type constant velocity universal joint as described in any one of Claims 1-3 in which the short fiber is planted in the said hair transplant part in the state inclined with respect to the outer surface of the said retaining ring at a fixed angle.

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