JP2017053399A - Manufacturing method of constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive manufacturing method of a velocity constant universal joint as a triball joint capable of being applied to a field where a peg-top type joint was a mainstream in terms of function and cost.SOLUTION: Provided is a manufacturing method of a constant velocity universal joint including: an outer ring having an annular space whose one end is opened; a torque tube constituting a tip tapering part in the annular space of the outer ring; and a ball assembled into a pocket of the torque tube. The outer ring is molded by sintering or casting. The torque tube is molded by narrowing a steel pipe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a constant velocity universal joint.

  As a constant velocity universal joint, there is a so-called triball joint shown in Patent Documents 1 to 3, and the like. As shown in FIGS. 16 and 17, the triball joint is composed of an outer ring 3 integrated with the central shaft 1 and a torque tube 7 formed with three ball holes (pockets). It is designed to convey the transmission power through.

  That is, as shown in FIGS. 16 and 17, the outer ring 3 has three track grooves 5 and 6 extending in the axial direction on at least one of the outer wall surface and the inner wall surface of the annular space 2 at intervals of 120 ° in the circumferential direction. Formed after. An end portion of the torque tube 7 is incorporated in the annular space 2 of the outer ring 3, and a pocket 8 is formed at a position corresponding to each of the track grooves 5 and 6. In order to prevent interference between the torque tube 7 and the tapered portion 9, the tapered portion 9 and the tapered portion 26 are formed. A ball 10 is held in the pocket 8.

  Further, a stop ring 11 is disposed on the inner surface of the outer wall surface on the opening side of the outer ring 3 to prevent the ball from coming off, and the opening of the outer ring 3 is sealed with a boot 12. That is, the boot 12 includes a large diameter portion 12a, a small diameter portion 12b, and a bellows portion 12c that connects the large diameter portion 12a and the small diameter portion 12b. The large diameter portion 12 a is externally fitted to the opening end portion of the outer ring 3 and tightened with the boot band 13, and the small diameter portion 12 b is externally fitted to a predetermined position of the torque tube 7 and tightened with the boot band 13.

  For this reason, it can be said that such a triball joint is a constant velocity universal joint that is excellent in grease sealing performance as compared to the coma joint as shown in FIG.

  By the way, as shown in FIG. 18, the top type joint connects a pair of drive yokes 15 and 16 via a top 17 or the like. The drive yokes 15 and 16 are provided with leg portions 18 and 19 having a pair of opposed facing support portions 18a, 18a, 19a and 19a, respectively. The frame 17 has a cubic shape and is interposed between the support portions 18a, 18a, 19a, and 19a. The top 17 is supported by the support portions 18a, 18a, 19a, and 19a via pins 20 and 21.

JP 2006-38204 A JP 2006-118703 A JP 2010-43665 A

  The outer ring 3 such as a tri-ball joint shown in FIGS. 17 and 18 is formed by machining the center axis by the center cutting and the track groove is formed by drilling / milling. Further, the torque tube 7 is all machined such as an outer diameter surface and an inner diameter surface.

  For this reason, in the triball joint, the smaller the size, the harder it is to process, and the higher the cost, and it has been difficult to provide the triball joint at a low cost that can compete with the top type joint shown in FIG. In other words, the operating angle is 10 degrees or less, and it is ideal for relatively simple use points (for example, applications that do not require excessive quality such as operation of only a change in angle phase with low load, such as a door opening / closing system of a nuclear facility, and a musical instrument pedal). It was difficult to provide a small triball joint at a low cost.

  Therefore, the present invention provides a low-cost manufacturing method for a constant velocity universal joint that is a triball joint that can be employed in a field where a koma-type joint has been mainstream in terms of function and cost.

  The method for manufacturing a constant velocity universal joint according to the present invention has an annular space with one end opened, and three track grooves extending in the axial direction on at least one of an outer wall surface and an inner wall surface of the annular space are 120 ° in the circumferential direction. An outer ring formed at an interval of the outer ring, an end portion is incorporated in the annular space of the outer ring, a pocket is formed at a position corresponding to each of the track grooves, and a tapered tip tapered portion is formed at the distal end portion. A method for manufacturing a constant velocity universal joint comprising a torque tube and a ball that is incorporated in a pocket of the torque tube and is rollable along the track groove, wherein the outer ring is sintered or cast. The torque tube is formed by drawing, and the torque tube is formed by steel pipe drawing. The torque tube is formed with a tip tapered portion and a drawing process at the center in order to prevent interference at the time of giving an angle.

  According to the method for manufacturing a constant velocity universal joint of the present invention, the outer ring is formed by sintering or casting, so that the centering of the center axis of the outer ring, which has been conventionally performed, can be eliminated. In addition, since the torque tube is formed by steel pipe drawing, it is possible to abolish the conventional machining process.

  The sintering process may be metal powder injection molding. Metal powder injection molding (hereinafter sometimes referred to as MIM processing) is a mixture of metal powder and a binder (plastic resin, etc.), injection molding into a mold, and a binder in a degreasing process. Is a molding method that produces high-density metal products by removing high temperature and sintering at high temperature. This is a metal processing technology that combines the advantages of metal powder metallurgy, which can be applied to difficult materials, and the advantages of plastic injection molding with a high degree of freedom.

  As the casting process, there is a lost wax manufacturing method. The lost wax manufacturing method is a casting method using wax (wax). The wax is press-fitted into the shape of a part manufactured with a mold, a prototype is manufactured, coated with a refractory material (ceramics, etc.), and then heated to braze. (Wax) is removed to create a cavity, and using this as a mold, the molten metal is poured and cast.

  The outer ring includes a cup portion that forms the annular space, and a connecting shaft having a fitting hole into which the driving shaft or the driven shaft is fitted, and after forming by sintering or casting, the inner diameter surface of the opening of the cup portion It is preferable to form a circumferential concave groove into which the stopper ring is fitted, and to form a screw hole in the direction perpendicular to the axis of the connecting shaft on the connecting shaft.

  The torque tube includes a pocket in which a ball is incorporated and a driven shaft or a rectangular tube portion connected to the drive shaft, and the tip portion is a tapered tip tapered portion. It is preferable to form a pocket in which the screw is incorporated and to form a screw hole in the direction perpendicular to the axis of the rectangular tube portion in the rectangular tube portion.

  Further, it is preferable that the torque tube is formed with a throttle portion between the tip tapered portion and the rectangular tube portion, and a leakage preventing member for preventing leakage of grease is disposed inside the joint at the throttle portion.

  In the present invention, since the boring of the center shaft of the outer ring and the machining of the outer diameter surface and the inner diameter surface of the torque tube can be abolished, a small triball joint type constant velocity universal joint that has been difficult to manufacture in the past. Can be manufactured at low cost. In particular, a method for manufacturing a constant velocity universal joint which is a triball joint that can be employed in a field where a koma-type joint has been mainstream in terms of function and cost can be provided at a low cost.

It is sectional drawing of the constant velocity universal joint manufactured with the manufacturing method of the constant velocity universal joint which concerns on this invention. It is sectional drawing of the outer ring | wheel of the constant velocity universal joint shown in FIG. It is the sectional view on the AA line of FIG. FIG. 3 is a sectional view taken along line B-B in FIG. 2. It is sectional drawing of the torque tube of the constant velocity universal joint shown in FIG. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is sectional drawing of the outer ring | wheel structure body in which the circumferential direction ditch | groove and the screw hole are not formed. It is the EE sectional view taken on the line of FIG. It is the FF sectional view taken on the line of FIG. It is a longitudinal cross-sectional view of the raw material before drawing. It is a cross-sectional view of the raw material before drawing. It is a longitudinal cross-sectional view of the torque tube structure after drawing. It is the GG sectional view taken on the line of FIG. It is the HH sectional view taken on the line of FIG. It is a longitudinal cross-sectional view of the conventional triball joint. It is a cross-sectional view of the triball joint shown in FIG. It is a perspective view of a top type joint.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2 show a constant velocity universal joint (triball joint) manufactured by the manufacturing method according to the present invention. The constant velocity universal joint includes an outer ring 31 in which track grooves 40 and 41 are formed, a track groove, and the like. A torque tube 34 forming a pocket 32 at a position corresponding to each of 40 and 41, and a ball 35 incorporated in the pocket 32 of the torque tube 34 and capable of rolling along the track grooves 40 and 41. It is a thing.

  As shown in FIGS. 2 to 4, the outer ring 31 includes a cup portion 31 a having a cylindrical portion 36 and a rolling shaft 31 b having a fitting hole (hexagonal hole) 37. A central shaft 38 is provided in the cup portion 31a, whereby an annular space 39 having one end opened is formed. Track grooves 40 and 41 are formed at intervals of 120 ° along the circumferential direction on the outer wall surface and the inner wall surface of the annular space 39. Further, a circumferential concave groove 42 is formed on the opening side of the inner diameter surface of the cup portion 31a, and a stopper ring 43 (see FIG. 1) for preventing the ball from falling is fitted into the circumferential concave groove 42. The connecting shaft 31 b is provided with a screw hole (tap hole) 44 along a direction orthogonal to the insertion hole 37.

  As shown in FIGS. 5 to 7, the torque tube 34 includes a pocket 32 in which the ball 35 is incorporated, and a square tube portion (hexagonal tube portion) 46 connected to the driven shaft or the drive shaft, and the tip. The portion is a tip tapered portion 33 having a tapered shape (a shape in which the outer diameter surface is reduced in diameter toward the tip). Three pockets 32 are formed at a 120 ° pitch along the circumferential direction, and a narrowed portion 45 is formed between the tip tapered portion 33 and the rectangular tube portion 46. The hexagonal cylinder portion 46 is provided with a screw hole (tap hole) 47 along a direction orthogonal to the axis.

  Further, as shown in FIG. 1, a leakage preventing member 48 for preventing the grease from flowing out inside the joint is housed inside the throttle portion 45. The leakage prevention member 48 is made of an elastic material such as CR rubber (chloroprene rubber), for example.

  As shown in FIG. 1, the opening of the outer ring 31 is sealed with a boot 50. That is, the boot 50 includes a large-diameter portion 50a, a small-diameter portion 50b, and a deformable portion 50c that connects the large-diameter portion 50a and the small-diameter portion 50b. The large diameter portion 50 a is externally fitted to the opening end of the outer ring 3, and the small diameter portion 50 b is externally fitted to the throttle portion 45 of the torque tube 34. In this case, adhesion (sealability) is ensured by tightening the large diameter portion 50a and the small diameter portion 50b without using a boot band. An inner flange portion 50d that bulges toward the inner diameter side is provided between the large diameter portion 50a and the deformable portion 50c, and the inner flange portion 50d is in contact with the opening end surface 52 of the outer ring 31. A flange 36a is formed on the outer periphery of the opening of the outer ring 3, and the boot 50 is positioned in the axial direction by sandwiching the flange 36a between the large diameter portion 50a and the inner flange 50d.

  Next, a method for manufacturing the outer ring 31 will be described. First, as shown in FIGS. 8 to 10, the outer ring constituting body 55 in which the circumferential concave groove 42 into which the stopper ring 43 is fitted and the screw hole (tap hole) 44 is not formed is formed. In this case, it shape | molds by a sintering process or a casting process. Sintering is a processing technique in which a material powder is heated and integrated at a temperature lower than the melting point while applying pressure.

  In this case, first, the metal powder as the main raw material of the sintered product is mixed using a mixer. In addition, as a metal powder, the raw material which can be made into powder, such as iron, copper, aluminum, titanium, nickel, can be used. Next, the metal powder is filled into a mold and compression molded. Thereafter, the compressed molded product is baked and hardened in a sintering furnace, and then set again in a mold and pressure is applied to increase the dimensional accuracy of the sintered product. Thereby, as shown in FIGS. 8 to 10, the outer ring constituting body 55 can be formed.

  After forming the outer ring constituting body 55 in this way, as shown in FIGS. 2 to 4, as shown in FIGS. 2 to 4, a cutting process for forming a circumferential groove 42 and a screw hole (tap hole) 44 in which the stopper ring 43 is fitted is performed. Do. If necessary, heat treatment such as carburizing and tempering or rust prevention treatment (for example, manganese phosphate coating treatment) is performed.

  Further, the outer ring 31 may be formed by a kind of metal powder injection molding of sintering. Metal powder injection molding (hereinafter sometimes referred to as MIM processing) is a mixture of metal powder and a binder (plastic resin, etc.), injection molding into a mold, and a binder in a degreasing process. Is a molding method that produces high-density metal products by removing high temperature and sintering at high temperature. This is a metal processing technology that combines the advantages of metal powder metallurgy, which can be applied to difficult materials, and the advantages of plastic injection molding with a high degree of freedom.

  The outer ring 31 may be formed by a casting process instead of the above-described sintering process. As the casting process, there is a lost wax manufacturing method. The lost wax manufacturing method is a casting method using wax (wax). The wax is press-fitted into the shape of a part manufactured with a mold, a prototype is manufactured, coated with a refractory material (ceramics, etc.), and then heated to braze. (Wax) is removed to create a cavity, and using this as a mold, the molten metal is poured and cast.

  Next, a method for manufacturing the torque tube 34 will be described. First, as shown in FIGS. 11 and 12, a steel pipe material 60 having an axial length, an outer diameter dimension, and an inner diameter dimension of predetermined dimensions is prepared. By subjecting the steel pipe material 60 to a drawing process, as shown in FIGS. 13 to 15, a tip tapered portion 33, a drawn portion 45, and a screw hole (tapped hole) 47 in which the pocket 32 is not formed are formed. A torque tube constituting body 61 having a hexagonal cylinder portion 46 not formed is formed.

  After the torque tube constituting body 61 is formed, a cutting process for forming a screw hole (tap hole) 47 in the pocket 32 and the hexagonal cylinder portion 46 is performed. Also in this case, heat treatment such as carburizing quenching and tempering and rust prevention treatment (for example, manganese phosphate coating treatment) are performed as necessary. In addition, phosphate treatment such as manganese phosphate coating treatment or zinc phosphate coating treatment, black dyeing treatment, chromate treatment or the like can be adopted as the rust prevention treatment for the outer ring 31 and the torque tube 34.

  A constant velocity universal joint can be assembled using the molded outer ring 31 and torque tube 34 as shown in FIG. That is, the torque tube 34 in which the ball 35 is incorporated in the pocket 32 is incorporated so that the tip tapered portion 33 is fitted into the annular space 39 of the outer ring 31. At this time, the ball 35 is fitted in the track grooves 40 and 41, and the torque tube 34 is provided with a leak preventing member 48.

  Thereafter, a stopper ring 43 for preventing the ball from slipping is fitted into the circumferential groove 42 of the outer ring 31 and the boot 50 is attached. In this case, when the tip tapered portion 33 is fitted into the annular space 39 of the outer ring 31, the small diameter portion 50 b of the boot 50 is attached to the throttle portion 45 of the torque tube 34, and the stopper ring 43 is fitted, The large-diameter portion 50a of 50 is fitted and fixed to the opening of the outer ring 31 with a margin. Thereby, this constant velocity universal joint can be assembled.

  In the present invention, since the boring of the central shaft 38 of the outer ring 31 and the machining of the outer and inner diameter surfaces of the torque tube 34 can be eliminated, a small triball joint type constant velocity, which has been difficult to manufacture in the past. A universal joint can be manufactured at low cost. In particular, a method for manufacturing a constant velocity universal joint that is a triball joint that can be employed in a field where a koma-type joint has been mainstream in terms of function and cost can be provided at low cost.

  The outer ring 31 can be formed by metal powder injection molding, a lost wax manufacturing method, or the like, and an outer ring utilizing the characteristics of these manufacturing methods can be configured. Further, in the outer ring 31, after forming by sintering or casting, formation of a circumferential concave groove 42 into which the stopper ring 43 is fitted, and a screw hole in a direction perpendicular to the axis of the connecting shaft 31b in the connecting shaft 31b 44 can be formed, so that it is excellent in workability and can stably provide a high-quality product.

  The torque tube 34 can be formed by steel pipe drawing, and the torque tube 34 can be configured by taking advantage of drawing characteristics. Further, in the torque tube 34, after the steel pipe drawing process, the pocket 32 into which the ball 35 is incorporated and the screw hole 47 in the direction perpendicular to the axis of the rectangular tube portion 46 are formed in the rectangular tube portion 46. Therefore, the torque tube 34 is excellent in processability and can stably provide a high-quality product.

  In the case where the leakage preventing member 48 is provided, it is possible to prevent the grease from flowing out from the inside of the joint, to prevent poor lubrication due to the lack of grease, and to prevent foreign matter from entering the inside of the joint via the torque tube 34. The torque tube is formed with a tip tapered portion 33 and a drawn portion 45 formed by drawing at the center in order to prevent interference at the time of giving an angle.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the boot 50 to be used may be a resin boot or a rubber boot. The large diameter portion and the small diameter portion may be tightened via the boot band. In addition, the application location (use location) is not limited to the door opening / closing system and instrument pedal part of a nuclear facility, but is a relatively simple use location with an operating angle of 10 degrees or less, and only changes the angle phase at low load. It can be used for applications that do not require excessive quality such as operation.

31 Outer ring 31a Cup part 31b Connecting shaft 32 Pocket 33 Tip taper part 34 Torque tube 35 Ball 37 Insertion hole (hexagonal hole)
39 Annular spaces 40, 41 Track grooves 42 Circumferential grooves 43 Stopper rings 45 Restrictions 46 Square tube (hexagon tube)
48 Leakage prevention member

Claims (6)

An outer ring having an annular space with one end open, and three track grooves extending in the axial direction on at least one of an outer wall surface and an inner wall surface of the annular space, and spaced apart by 120 ° in the circumferential direction; A torque tube in which an end portion is incorporated in the annular space of the outer ring, a pocket is formed at a position corresponding to each of the track grooves, and a tip portion is a tapered tip tapered portion, and a pocket of the torque tube A method for manufacturing a constant velocity universal joint including a ball incorporated in the track groove and capable of rolling along the track groove,
A method of manufacturing a constant velocity universal joint, wherein the outer ring is formed by sintering or casting, and the torque tube is formed by steel pipe drawing.   The method for manufacturing a constant velocity universal joint according to claim 1, wherein the sintering includes metal powder injection molding.   The method for manufacturing a constant velocity universal joint according to claim 1, wherein the casting includes a lost wax manufacturing method.   The outer ring includes a cup portion that forms the annular space, and a connecting shaft having a fitting hole into which the driving shaft or the driven shaft is fitted, and after forming by sintering or casting, the inner diameter surface of the opening of the cup portion 4. The method according to claim 1, further comprising: forming a circumferential concave groove into which the stopper ring is fitted, and forming a screw hole in the direction perpendicular to the axis of the connecting shaft on the connecting shaft. A method for producing the constant velocity universal joint according to claim 1.   The torque tube includes a pocket in which a ball is incorporated and a driven shaft or a rectangular tube portion connected to the drive shaft, and the tip portion is a tapered tip tapered portion. The formation of the pocket in which the is incorporated and the formation of a screw hole in the direction perpendicular to the axis of the rectangular tube portion in the rectangular tube portion. A method for manufacturing a constant velocity universal joint.   The torque tube is characterized in that a throttle portion is formed between the tip tapered portion and the rectangular tube portion, and a leakage prevention member for preventing grease leakage is disposed inside the joint in the throttle portion. 6. The method for manufacturing a constant velocity universal joint according to any one of items 5 to 6.

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