JP2013217478A - Inner member of constant velocity universal joint, and method for producing same - Google Patents
Inner member of constant velocity universal joint, and method for producing same Download PDFInfo
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- JP2013217478A JP2013217478A JP2012090183A JP2012090183A JP2013217478A JP 2013217478 A JP2013217478 A JP 2013217478A JP 2012090183 A JP2012090183 A JP 2012090183A JP 2012090183 A JP2012090183 A JP 2012090183A JP 2013217478 A JP2013217478 A JP 2013217478A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
- F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
- F16D3/20—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members
- F16D3/202—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members one coupling part having radially projecting pins, e.g. tripod joints
- F16D3/205—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members one coupling part having radially projecting pins, e.g. tripod joints the pins extending radially outwardly from the coupling part
- F16D3/2055—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members one coupling part having radially projecting pins, e.g. tripod joints the pins extending radially outwardly from the coupling part having three pins, i.e. true tripod joints
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
- F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
- F16D3/20—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members
- F16D3/22—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts
- F16D3/223—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts the rolling members being guided in grooves in both coupling parts
- F16D2003/22313—Details of the inner part of the core or means for attachment of the core on the shaft
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2250/00—Manufacturing; Assembly
- F16D2250/0038—Surface treatment
- F16D2250/0053—Hardening
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2300/00—Special features for couplings or clutches
- F16D2300/10—Surface characteristics; Details related to material surfaces
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2300/00—Special features for couplings or clutches
- F16D2300/12—Mounting or assembling
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Heat Treatment Of Articles (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
この発明は、等速自在継手の内方部材およびその製造方法に関し、特に、自動車、航空機、船舶や各種産業機械などの動力伝達部に使用される等速自在継手の内方部材およびその製造方法に関する。 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner member of a constant velocity universal joint and a manufacturing method thereof, and more particularly to an inner member of a constant velocity universal joint used in a power transmission part of an automobile, an aircraft, a ship, various industrial machines, and the like. About.
例えば、自動車のエンジンから車輪に回転力を等速で伝達するドライブシャフトやプロペラシャフト等に組込まれる等速自在継手には、固定式等速自在継手と摺動式等速自在継手の二種がある。これらの等速自在継手は、駆動側と従動側の二軸を連結して、その二軸が作動角をとっても等速で回転を伝達し得る構造を備えている。 For example, there are two types of constant velocity universal joints built into drive shafts and propeller shafts that transmit rotational force from an automobile engine to wheels at a constant speed: fixed constant velocity universal joints and sliding constant velocity universal joints. is there. These constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected and rotation can be transmitted at a constant speed even if the two shafts have an operating angle.
自動車のエンジンから駆動車輪に動力を伝達するドライブシャフトは、デフと車輪との相対的な位置関係の変化による角度変位と軸方向変位に対応する必要があるため、一般的にデフ側(インボード側)に角度変位と軸方向変位に対応できる摺動式等速自在継手を、駆動車輪側(アウトボード側)に大きな作動角が取れる固定式等速自在継手をそれぞれ装着し、両等速自在継手をシャフトで連結した構造を有する。この等速自在継手の内方部材とシャフトの連結構造として、スプライン結合(セレーション結合も含む。以下、本明細書および特許請求の範囲において同じとする。)が使用されている。 The drive shaft that transmits power from the engine of the automobile to the drive wheel must cope with the angular displacement and axial displacement caused by the change in the relative positional relationship between the differential and the wheel. Side) is equipped with a sliding type constant velocity universal joint that can handle angular displacement and axial displacement, and a fixed constant velocity universal joint with a large operating angle on the drive wheel side (outboard side). It has a structure in which joints are connected by a shaft. As a connection structure between the inner member of the constant velocity universal joint and the shaft, spline coupling (including serration coupling; hereinafter the same applies in the present specification and claims) is used.
例えば、摺動式等速自在継手の一種にトリポード型等速自在継手がある。トリポード型等速自在継手61は、図14に示すように、外側継手部材62、内方部材としてのトリポード部材63、転動体65および球面ローラ64を主な構成とする。外側継手部材62の内周部に3本のトラック溝66が軸方向に形成され、各トラック溝66の両側にそれぞれローラ案内面67が軸方向に形成されている。トリポード部材63は、そのボス部63aより3本の脚軸63bが放射状に形成されている。脚軸63bに多数の転動体65を介して球面ローラ64が嵌合され、転動体の両端にワッシャ69、70を介在させ、ワッシャ69は止め輪68により位置決めされている。脚軸63bの外周面は転動体65の内側軌道面を形成し、球面ローラ64の内周面は転動体65の外側軌道面を形成している。上記の構成により、転動体65の列が脚軸63b上で案内されると共に、球面ローラ64は、転動体65上で回転自在で、かつ脚軸63bの軸線方向に移動可能となっている。球面ローラ64は、外側継手部材62のローラ案内面67に回転自在に収容されている。このような構造により、外側継手部材62とトリポード部材63との間の相対的な軸方向変位や角度変位が吸収され、回転が等速で伝達される。トリポード部材63のボス部63aの内周面72にスプライン73が形成され、このスプライン73とシャフト71のスプライン74が嵌合され、トルク伝達可能に連結される。 For example, a tripod type constant velocity universal joint is one type of sliding type constant velocity universal joint. As shown in FIG. 14, the tripod constant velocity universal joint 61 mainly includes an outer joint member 62, a tripod member 63 as an inward member, a rolling element 65, and a spherical roller 64. Three track grooves 66 are formed in the axial direction on the inner peripheral portion of the outer joint member 62, and roller guide surfaces 67 are formed in the axial direction on both sides of each track groove 66. The tripod member 63 has three leg shafts 63b formed radially from the boss portion 63a. A spherical roller 64 is fitted to the leg shaft 63b via a large number of rolling elements 65, and washers 69, 70 are interposed at both ends of the rolling elements, and the washer 69 is positioned by a retaining ring 68. The outer peripheral surface of the leg shaft 63 b forms the inner raceway surface of the rolling element 65, and the inner peripheral surface of the spherical roller 64 forms the outer raceway surface of the rolling element 65. With the above configuration, the row of rolling elements 65 is guided on the leg shaft 63b, and the spherical roller 64 is rotatable on the rolling element 65 and is movable in the axial direction of the leg shaft 63b. The spherical roller 64 is rotatably accommodated on the roller guide surface 67 of the outer joint member 62. With such a structure, relative axial displacement and angular displacement between the outer joint member 62 and the tripod member 63 are absorbed, and rotation is transmitted at a constant speed. A spline 73 is formed on the inner peripheral surface 72 of the boss portion 63a of the tripod member 63, and the spline 73 and the spline 74 of the shaft 71 are fitted and connected so as to transmit torque.
一方、固定式等速自在継手の一種にツェッパ型等速自在継手がある。ツェッパ型等速自在継手91は、図17および図18に示すように、外側継手部材92、内方部材としての内側継手部材93、ボール94および保持器95を主な構成とする。外側継手部材92の球状内周面98には複数のトラック溝96が円周方向等間隔に、かつ軸方向に沿って形成されている。内側継手部材93の球状外周面99には、外側継手部材92のトラック溝96と対向するトラック溝97が円周方向等間隔に、かつ軸方向に沿って形成されている。外側継手部材92のトラック溝96と内側継手部材93のトラック溝97との間にトルクを伝達する複数のボール94が介在されている。外側継手部材92の球状内周面98と内側継手部材93の球状外周面99の間に、ボール94を保持する保持器95が配置されている。外側継手部材92の球状内周面98と内側継手部材93の球状外周面99の曲率中心は、いずれも、継手の中心Oに形成されている。また、保持器95の球状外周面100および球状内周面101の曲率中心も継手の中心Oに形成されている。これに対して、外側継手部材92のトラック溝96の曲率中心Aと、内側継手部材93のトラック溝97の曲率中心Bとは、継手の中心Oに対して軸方向に等距離オフセットされている。これにより、継手が作動角をとった場合、外側継手部材92と内側継手部材93の二軸間で回転が等速で伝達されることになる。内側継手部材93の内周面105にスプライン106が形成され、このスプライン106とシャフト102のスプライン107が嵌合され、トルク伝達可能に連結されている。 On the other hand, there is a Rzeppa type constant velocity universal joint as one type of fixed type constant velocity universal joints. As shown in FIGS. 17 and 18, the Rzeppa constant velocity universal joint 91 mainly includes an outer joint member 92, an inner joint member 93 as an inner member, a ball 94, and a cage 95. A plurality of track grooves 96 are formed in the spherical inner peripheral surface 98 of the outer joint member 92 at equal intervals in the circumferential direction and along the axial direction. On the spherical outer peripheral surface 99 of the inner joint member 93, track grooves 97 facing the track grooves 96 of the outer joint member 92 are formed at equal intervals in the circumferential direction and along the axial direction. A plurality of balls 94 for transmitting torque are interposed between the track grooves 96 of the outer joint member 92 and the track grooves 97 of the inner joint member 93. A cage 95 that holds the ball 94 is disposed between the spherical inner peripheral surface 98 of the outer joint member 92 and the spherical outer peripheral surface 99 of the inner joint member 93. The centers of curvature of the spherical inner peripheral surface 98 of the outer joint member 92 and the spherical outer peripheral surface 99 of the inner joint member 93 are both formed at the center O of the joint. Further, the centers of curvature of the spherical outer peripheral surface 100 and the spherical inner peripheral surface 101 of the cage 95 are also formed at the center O of the joint. On the other hand, the center of curvature A of the track groove 96 of the outer joint member 92 and the center of curvature B of the track groove 97 of the inner joint member 93 are offset by an equal distance in the axial direction with respect to the center O of the joint. . Thereby, when the joint takes an operating angle, rotation is transmitted at a constant speed between the two shafts of the outer joint member 92 and the inner joint member 93. A spline 106 is formed on the inner peripheral surface 105 of the inner joint member 93, and the spline 106 and the spline 107 of the shaft 102 are fitted and connected so that torque can be transmitted.
上記の等速自在継手61、91の内方部材としてのトリポード部材63や内側継手部材93は、周方向の肉厚が変化する形状であるので、スプラインの熱処理変形に対する対策技術が公開されている(特許文献1)。 Since the tripod member 63 and the inner joint member 93 as the inner members of the constant velocity universal joints 61 and 91 have a shape in which the thickness in the circumferential direction changes, a countermeasure technique for heat treatment deformation of the spline is disclosed. (Patent Document 1).
図15に、トリポード部材を拡大して示す。従来、トリポード部材63は、図16に示すように、バー材切断工程S1、球状化焼なまし工程S2、ボンデ処理工程S3、冷間鍛造工程S4、旋削加工工程S5、ブローチ加工工程S6、熱処理工程S7、研削加工工程S8を経て製作される。トリポード部材63は、強度や耐摩耗性及び耐はく離性を要求されることから、上記の製作工程のように浸炭焼入焼戻しなどの熱処理を施して硬度を高めるようにしている。ところが、図15に示すように、トリポード部材63は、ボス部63aから脚軸63bが放射状に突出した形状であるので、周方向での肉厚の変化が大きい。 FIG. 15 shows an enlarged tripod member. Conventionally, as shown in FIG. 16, the tripod member 63 includes a bar material cutting step S1, a spheroidizing annealing step S2, a bondering step S3, a cold forging step S4, a turning step S5, a broaching step S6, and a heat treatment. It is manufactured through step S7 and grinding step S8. Since the tripod member 63 is required to have strength, wear resistance, and peel resistance, the heat treatment such as carburizing, quenching, and tempering is performed to increase the hardness as in the above manufacturing process. However, as shown in FIG. 15, the tripod member 63 has a shape in which the leg shaft 63b protrudes radially from the boss portion 63a, so that the change in the thickness in the circumferential direction is large.
このような肉厚の変化が大きい部品を浸炭焼入焼戻しした場合、冷却速度が部位により異なるため熱処理変形が大きくなる。また、焼入れでの変態により膨張が生じ、この膨張は部品の体積に比例する。そのため、肉厚の厚い部位は大きく膨張し、逆に肉厚の薄い部位は小さな膨張となり、その結果、トリポード部材63のスプライン73のピッチ円Pは、熱処理前の真円形状から、図15に示すように、肉厚の厚い脚軸形成部位Dにおいてピッチ円Pの直径が大きく、肉厚の薄い円筒状部位Cではピッチ円Pの直径が小さくなり、数十μm程度の直径差を有する略三角形状に変形する。図15では、理解しやすいように直径差を誇張して図示している。 When such a part having a large change in thickness is carburized, quenched, and tempered, the heat treatment deformation becomes large because the cooling rate differs depending on the part. In addition, expansion occurs due to transformation during quenching, and this expansion is proportional to the volume of the part. Therefore, the thick part expands greatly, and conversely the thin part becomes small expansion. As a result, the pitch circle P of the spline 73 of the tripod member 63 changes from a perfect circular shape before heat treatment to FIG. As shown in the figure, the diameter of the pitch circle P is large in the thick leg shaft forming portion D, and the diameter of the pitch circle P is small in the thin cylindrical portion C, which has a diameter difference of about several tens of μm. Deforms into a triangular shape. In FIG. 15, the diameter difference is exaggerated for easy understanding.
上記のような熱処理変形が生じるため、トリポード部材63のスプライン73にシャフト71のスプライン74を嵌合結合してトルクを伝達する場合、肉厚の薄い円筒状部位Cのスプライン73に大きな負荷がかかり、脚軸形成部位Dのスプライン73には小さな負荷となって、スプライン73の各歯に作用する応力が不均一になる。これにより、トリポード部材63の疲労強度の低下や疲労強度の大きなバラツキを招く場合がある。また、このようなトリポード部材63の熱処理変形によるスプライン負荷の不均一により、嵌合するシャフトの強度を低下させる場合がある。このような状況にあるが、トリポード部材63のスプライン73の熱処理変形は、容易に、また経済的に研削仕上げすることが難しいこともあって、熱処理後仕上げ加工されずに使用されることが多い。 Due to the heat treatment deformation as described above, when torque is transmitted by fitting and connecting the spline 74 of the shaft 71 to the spline 73 of the tripod member 63, a large load is applied to the spline 73 of the thin cylindrical portion C. A small load is applied to the spline 73 of the leg shaft forming portion D, and the stress acting on each tooth of the spline 73 becomes non-uniform. Thereby, the fall of the fatigue strength of the tripod member 63 and the big variation in fatigue strength may be caused. In addition, due to the non-uniform spline load due to the heat treatment deformation of the tripod member 63, the strength of the shaft to be fitted may be reduced. Under such circumstances, the heat treatment deformation of the spline 73 of the tripod member 63 is often used without finishing after heat treatment because it is difficult to grind easily and economically. .
図19に、ツェッパ型等速自在継手の内側継手部材を拡大して示す。内側継手部材93についても、前述したトリポード部材63とほぼ同様の工程を経て製作される。内側継手部材93は、トラック溝形成部位Eと球状外周面形成部位Fからなり、肉厚が周方向で変化する。この内側継手部材93の肉厚の変化量は、トリポード部材63ほど大きくはないが、内側継手部材93の内周面105に形成されたスプライン106のピッチ円Pは多角形状の熱処理変形が生じ、前述したトリポード部材63と同様の問題がある。図19でも、多角形状の熱処理変形を理解しやすいように誇張して図示している。 FIG. 19 shows an enlarged inner joint member of a Rzeppa constant velocity universal joint. The inner joint member 93 is also manufactured through substantially the same process as the tripod member 63 described above. The inner joint member 93 includes a track groove forming portion E and a spherical outer peripheral surface forming portion F, and the thickness changes in the circumferential direction. The amount of change in the thickness of the inner joint member 93 is not as great as that of the tripod member 63, but the pitch circle P of the spline 106 formed on the inner peripheral surface 105 of the inner joint member 93 undergoes heat treatment deformation in a polygonal shape, There is a problem similar to that of the tripod member 63 described above. In FIG. 19, the polygonal heat treatment deformation is exaggerated for easy understanding.
上記の問題に対して、特許文献1に記載の技術は、内側継手部材のセレーションの熱処理前形状を、その熱処理による変形量を予め考慮して、薄肉部の内径寸法を厚肉部の内径寸法よりも大きくするものである。しかし、この技術では、不可避的に発生する熱処理変形のバラツキを解消することができない。したがって、スプラインの各歯に作用する応力を均一するには限界がある。また、トリポード部材の破壊の起点となるスプラインの歯底(大径)の表面に浸炭異常層が形成されるので、強度面での改善も必要であることが分かった。 In order to solve the above problem, the technique described in Patent Document 1 considers the shape before serration of the inner joint member, the deformation amount due to the heat treatment in advance, and the inner diameter dimension of the thin part is changed to the inner diameter dimension of the thick part. It is something that makes it bigger. However, this technique cannot eliminate variations in heat treatment deformation that inevitably occur. Therefore, there is a limit to uniform the stress acting on each tooth of the spline. Further, it was found that since an abnormal carburization layer is formed on the surface of the spline bottom (large diameter) that becomes the starting point of the tripod member destruction, improvement in strength is also necessary.
また、特許文献1には、内側継手部材の熱処理後に、セレーションを形成することも記載されている。しかし、この場合には、超硬工具鋼に特殊なコーティングを施したハードブローチやワイヤカットなどの仕上げ加工が必要となり、このため、新たな設備の導入や加工時間が長いことにより、大幅なコストの増加を招くため問題がある。 Patent Document 1 also describes that serrations are formed after heat treatment of the inner joint member. However, in this case, finishing work such as hard broaching and wire cutting with special coating on carbide tool steel is required, which leads to significant costs due to the introduction of new equipment and long processing time. This causes problems.
上記のような問題に鑑み、本発明は、加工時間の増加やコスト増加を抑制しつつ、スプラインの各歯に作用する応力を均一にし、高強度な等速自在継手の内方部材を提供することを目的とする。 In view of the problems as described above, the present invention provides an inner member of a constant velocity universal joint having high strength by making the stress acting on each tooth of the spline uniform while suppressing increase in processing time and cost. For the purpose.
本発明者らは、上記の目的を達成するために種々検討した結果、内方部材のスプライン形成部を一般的なブローチ加工が可能な硬度とし、浸炭焼入焼戻し後のブローチ加工により、真円度が高く、かつ浸炭異常層を除去したスプラインを形成するという新たな着想を行い、本発明に至った。 As a result of various studies to achieve the above object, the present inventors have made the spline forming portion of the inner member a hardness capable of general broaching, and broaching after carburizing, quenching and tempering, A new idea of forming a spline having a high degree of removal and a carburized abnormal layer was achieved, and the present invention was achieved.
前述の目的を達成するための技術的手段として、本発明は、外周にトルク伝達要素を支承する軌道面が形成され、内周にスプライン部が形成された等速自在継手の内方部材であって、この内方部材が鋼材からなり局部的に浸炭を抑制した浸炭焼入焼戻しが施されており、前記スプライン部を不完全焼入部とし、かつ、少なくともスプライン大径の表面を浸炭異常層のない金属組織とすると共に、前記スプライン部を除いた表面にスプライン部より炭素濃度の高い焼入部を形成したことを特徴とする。 As technical means for achieving the above-mentioned object, the present invention is an inner member of a constant velocity universal joint in which a raceway surface for supporting a torque transmitting element is formed on the outer periphery and a spline portion is formed on the inner periphery. The inner member is made of steel and is subjected to carburizing, quenching and tempering that suppresses carburizing locally, the spline portion is an incompletely quenched portion, and at least the surface of the spline large diameter is a carburizing abnormal layer. A hard metal part having a higher carbon concentration than the spline part is formed on the surface excluding the spline part.
上記の構成により、等速自在継手の内方部材のスプライン形成部を一般的なブローチ加工が可能な硬度とし浸炭焼入焼戻し後にブローチ加工することにより、真円度の高いピッチ円を有するスプラインが形成され、かつ、歯底部の浸炭異常層が除去されているので、高強度でかつ強度のバラツキの小さな内方部材を実現することができる。同時に、当該内方部材に嵌合されるシャフトの強度を向上させることができる。 With the above configuration, the spline forming portion of the inner member of the constant velocity universal joint has a hardness capable of general broaching and broached after carburizing, quenching and tempering, so that a spline having a highly round pitch circle is obtained. Since it is formed and the carburizing abnormal layer of the tooth bottom is removed, an inner member having high strength and small variation in strength can be realized. At the same time, the strength of the shaft fitted to the inner member can be improved.
ここで、一般的なブローチとは、通常の高速度工具鋼(SKH55やSKH51)や、これに相当する鋼材(モリブデン系高速度工具鋼)を熱処理しHRC63以上に焼入焼戻し後、仕上げ加工したブローチを意味する。 Here, a general broach is a normal high-speed tool steel (SKH55 or SKH51) or a corresponding steel material (molybdenum-based high-speed tool steel), which is quenched and tempered to HRC63 or higher and then finished. Means brooches.
具体的には、上記のスプライン大径の表面硬さをHv230以上でHv390以下とすることが好ましい。さらに好ましくはHv260以上でHv340以下とする。表面硬さがHv390を越えると、ブローチの寿命が著しく低下すると共にトラニオンの強度も低下する。一方、表面硬さがHv230未満では、スプラインの強度の低下を招き、また、浸炭作業面では、浸炭の拡散を完全に防止する必要が生じ、大掛かりな治工具が必要となり、生産性の低下とコストの増加を招き、好ましくない。表面硬さの測定部位は、スプライン軸方向中央の円周方向断面の大径表面から0.2mmである。 Specifically, the surface hardness of the large spline diameter is preferably Hv230 or more and Hv390 or less. More preferably, it is set to Hv260 or more and Hv340 or less. When the surface hardness exceeds Hv390, the life of the broach is remarkably reduced and the strength of the trunnion is also reduced. On the other hand, if the surface hardness is less than Hv230, the spline strength is reduced, and on the carburizing work surface, it is necessary to completely prevent the carburization from spreading, which requires a large jig and tool, resulting in a decrease in productivity. This increases the cost and is not preferable. The surface hardness measurement site is 0.2 mm from the large-diameter surface of the circumferential section at the center of the spline axis direction.
上記の内方部材をクロム鋼とすることが好ましい。クロム鋼の方が、クロムモリブデン鋼より内周部の硬度が低下するためブローチの寿命が向上する。また、モリブデンを添加しない低コストのクロム鋼でも高強度になることが判明した。 The inner member is preferably chrome steel. Chrome steel has a lower inner peripheral hardness than chromium molybdenum steel, so the life of the broach is improved. It was also found that low-strength chromium steel with no molybdenum added has high strength.
上記の内方部材がトリポード部材であることを特徴とする。トリポード部材は、ボス部から3本の脚軸が放射状に突出した形状であるので、周方向での肉厚の変化が大きく、熱処理変形が大きい。したがって、トリポード部材に適用するとより効果が大きい。 The inner member is a tripod member. Since the tripod member has a shape in which the three leg shafts protrude radially from the boss portion, the change in the thickness in the circumferential direction is large, and the heat treatment deformation is large. Therefore, it is more effective when applied to a tripod member.
また、製造方法として、外周にトルク伝達要素を支承する軌道面が形成され、内周にスプライン部が形成された等速自在継手の内方部材の製造方法であって、前記内方部材を鋼材とし局部的に浸炭を抑制した浸炭焼入焼戻しを施すことにより、前記スプライン部を形成する部分を不完全焼入部とすると共に、当該部分を除いた表面に焼入部を形成し、この熱処理後に前記スプライン孔部を形成する部分をブローチ加工することを特徴とする。 Further, as a manufacturing method, there is a manufacturing method of an inner member of a constant velocity universal joint in which a raceway surface for supporting a torque transmitting element is formed on an outer periphery and a spline portion is formed on an inner periphery, the inner member being a steel material By performing carburizing quenching and tempering that locally suppresses carburizing, the portion forming the spline portion is an incompletely quenched portion, and a quenched portion is formed on the surface excluding the portion. A part that forms the spline hole is broached.
上記の構成により、等速自在継手の内方部材のスプライン形成部を一般的なブローチ加工が可能な硬度とし浸炭焼入焼戻し後にブローチ加工することにより、ブローチの寿命向上が図れると共に、新たな設備の導入や長い加工時間によるコストの増加や生産性の低下を抑制することができる。また、本製造方法に基づく内方部材は、真円度の高いピッチ円を有するスプラインが形成され、かつ、歯底部の浸炭異常層が除去されているので、高強度でかつ強度のバラツキの小さな内方部材を得ることができる。 With the above configuration, the spline forming part of the inner member of the constant velocity universal joint has a hardness that allows general broaching, and broaching after carburizing, quenching and tempering can improve the life of the broach and provide new equipment. The increase in cost and the decrease in productivity due to the introduction of the material and the long processing time can be suppressed. Further, the inner member based on this manufacturing method is formed with a spline having a pitch circle with a high roundness, and the carburizing abnormal layer at the bottom of the tooth is removed, so that it has high strength and small variation in strength. An inward member can be obtained.
本発明によれば、等速自在継手の内方部材のスプライン孔部が真円度の高いピッチ円に形成され、かつ、歯底部の浸炭異常層が除去されることにより、高強度でかつ強度のバラツキの小さな内方部材を実現することができる。また、本発明の製造方法によれば、ブローチの寿命向上が図れると共に、新たな設備の導入や長い加工時間によるコストの増加や生産性の低下を抑制することができる。 According to the present invention, the spline hole portion of the inner member of the constant velocity universal joint is formed in a pitch circle having a high roundness, and the carburizing abnormal layer in the tooth bottom portion is removed, thereby providing high strength and strength. It is possible to realize an inner member with a small variation. Further, according to the manufacturing method of the present invention, it is possible to improve the life of the broach, and to suppress an increase in cost and a decrease in productivity due to the introduction of new equipment and a long processing time.
以下に本発明の実施の形態を図面に基づいて説明する。 Embodiments of the present invention will be described below with reference to the drawings.
本発明の第1の実施形態に係る等速自在継手の内方部材を図1および図2に示す。この等速自在継手は摺動式トリポード型等速自在継手である。トリポード型等速自在継手1は、外側継手部材2、内方部材としてのトリポード部材3、トルク伝達要素としての転動体5および球面ローラ4を主な構成とする。外側継手部材2の内周部に3本のトラック溝6が軸方向に形成され、各トラック溝6の両側にそれぞれローラ案内面7が軸方向に形成されている。トリポード部材3は、そのボス部3aより3本の脚軸3bが放射状に形成されている。脚軸3bに多数の転動体5を介して球面ローラ4が嵌合され、転動体の両端にワッシャ9、10を介在させ、ワッシャ9は止め輪8により位置決めされている。脚軸3bの外径面は転動体5の内側軌道面を形成し、球面ローラ4の内径面は転動体5の外側軌道面を形成している。転動体5の列が脚軸3b上で案内されると共に、球面ローラ4は、転動体5上で回転自在で、かつ脚軸3bの軸線方向に移動可能となっている。また、球面ローラ4は、外側継手部材2のローラ案内面7に回転自在に収容されている。このような構造により、外側継手部材2とトリポード部材3との間の相対的な軸方向変位や角度変位が吸収され、回転が等速で伝達される。 An inward member of the constant velocity universal joint according to the first embodiment of the present invention is shown in FIGS. This constant velocity universal joint is a sliding tripod type constant velocity universal joint. The tripod type constant velocity universal joint 1 includes an outer joint member 2, a tripod member 3 as an inner member, rolling elements 5 and a spherical roller 4 as torque transmission elements. Three track grooves 6 are formed in the axial direction on the inner periphery of the outer joint member 2, and roller guide surfaces 7 are formed in the axial direction on both sides of each track groove 6. The tripod member 3 has three leg shafts 3b formed radially from its boss 3a. The spherical roller 4 is fitted to the leg shaft 3 b via a large number of rolling elements 5, and washers 9 and 10 are interposed at both ends of the rolling elements, and the washer 9 is positioned by a retaining ring 8. The outer diameter surface of the leg shaft 3 b forms the inner raceway surface of the rolling element 5, and the inner diameter surface of the spherical roller 4 forms the outer raceway surface of the rolling element 5. The row of rolling elements 5 is guided on the leg shaft 3b, and the spherical roller 4 is rotatable on the rolling element 5 and is movable in the axial direction of the leg shaft 3b. The spherical roller 4 is rotatably accommodated on the roller guide surface 7 of the outer joint member 2. With such a structure, relative axial displacement and angular displacement between the outer joint member 2 and the tripod member 3 are absorbed, and rotation is transmitted at a constant speed.
トリポード部材3のボス部3aの内周面12にスプライン13が形成され、このスプライン13とシャフト11のスプライン14が嵌合され、トルク伝達可能に連結されている。 A spline 13 is formed on the inner peripheral surface 12 of the boss 3a of the tripod member 3, and the spline 13 and the spline 14 of the shaft 11 are fitted and connected so as to be able to transmit torque.
図2にトリポード部材3の正面図を拡大して示す。トリポード部材3は、ボス部3aから3本の脚軸3bが放射状に突出し、転動体5の内側軌道面となる脚軸3bの外径面15は、例えば、研削加工により仕上げられている。ボス部3aの内周面12にスプライン13が形成されている。図示のように、本実施形態のトラニオン部材3のスプライン13は、熱処理変形がなく、肉厚の厚い脚軸形成部位Dと肉厚の薄い円筒状部位Cの全周にわたって真円度の高いピッチ円Pで形成されている。したがって、このスプライン13にシャフト11のスプライン14を嵌合してトルクを伝達するとき、各スプライン13、14の各歯に作用する応力は可及的に均一になる。このトラニオン部材3は、後述する局部的に浸炭を抑制した浸炭焼入焼戻しが施されており、スプライン13が形成された部位13sは不完全焼入部で形成され、このスプライン13が形成された部位13sを除いた表面は焼入部となっている。以下、スプライン13が形成された部位13sをスプライン形成部13sと略称する。本実施形態のトラニオン部材3のスプライン13において、熱処理変形がなく、真円度の高いピッチ円Pで形成される理由は、スプライン形成部13sを、一般的なブローチ加工が可能な硬度を有する不完全焼入部としているので、浸炭焼入焼戻し後に、ブローチ加工によりスプライン13を形成することができるからである。すなわち、前述した従来技術のようなスプラインの熱処理変形の問題は生じない。 FIG. 2 is an enlarged front view of the tripod member 3. In the tripod member 3, three leg shafts 3b project radially from the boss portion 3a, and the outer diameter surface 15 of the leg shaft 3b serving as the inner raceway surface of the rolling element 5 is finished by, for example, grinding. Splines 13 are formed on the inner peripheral surface 12 of the boss 3a. As shown in the figure, the spline 13 of the trunnion member 3 of the present embodiment is not deformed by heat treatment, and has a high roundness pitch over the entire circumference of the thick leg shaft forming portion D and the thin thick cylindrical portion C. It is formed by a circle P. Therefore, when the spline 14 of the shaft 11 is fitted to the spline 13 and torque is transmitted, the stress acting on the teeth of the splines 13 and 14 becomes as uniform as possible. The trunnion member 3 is subjected to carburizing, quenching, and tempering that suppresses carburizing locally, which will be described later, and the portion 13s where the spline 13 is formed is formed as an incompletely quenched portion, and the portion where the spline 13 is formed. The surface excluding 13s is a hardened part. Hereinafter, the portion 13s where the spline 13 is formed is abbreviated as a spline forming portion 13s. The spline 13 of the trunnion member 3 of the present embodiment is not deformed by heat treatment and is formed with a pitch circle P having a high roundness because the spline forming portion 13s has a hardness that allows general broaching. This is because the complete quenching portion can be used to form the spline 13 by broaching after carburizing quenching and tempering. That is, there is no problem of heat treatment deformation of the spline as in the prior art described above.
また、ブローチ加工により浸炭異常層が除去されるので、トリポード部材3の破壊の起点となるスプライン13の歯底(大径)の表面が浸炭異常層のない金属組織となる。したがって、トリポード部材3の疲労強度が向上し、同時に、トリポード部材3に嵌合されるシャフト11の強度を向上させることができる。 Moreover, since the carburizing abnormal layer is removed by broaching, the surface of the tooth bottom (large diameter) of the spline 13 that becomes the starting point of the breakage of the tripod member 3 has a metal structure having no carburizing abnormal layer. Therefore, the fatigue strength of the tripod member 3 is improved, and at the same time, the strength of the shaft 11 fitted to the tripod member 3 can be improved.
次に、前述したトリポード部材3を得るための本発明の製造方法についての実施形態について図3〜7に基づいて説明する。図3にトリポード部材3の製造工程の概要を示す。トリポード部材3は、図示のようにバー材切断工程S1、球状化焼なまし工程S2、ボンデ処理工程S3、冷間鍛造工程S4、旋削加工工程S5、熱処理工程S6、ブローチ加工工程S7、研削加工工程S8を経て製作される。本実施形態の製造工程は、従来の製造工程(図16参照)を比較すると、熱処理工程S6の内容と製造工程の順序として熱処理後にスプラインのブローチ加工工程S7を施すところが異なる。 Next, an embodiment of the manufacturing method of the present invention for obtaining the tripod member 3 will be described with reference to FIGS. FIG. 3 shows an outline of the manufacturing process of the tripod member 3. The tripod member 3 includes a bar cutting process S1, a spheroidizing annealing process S2, a bonding process S3, a cold forging process S4, a turning process S5, a heat treatment process S6, a broaching process S7, and a grinding process as shown in the figure. It is manufactured through step S8. The manufacturing process of this embodiment differs from the conventional manufacturing process (see FIG. 16) in that the spline broaching process S7 is performed after the heat treatment as the content of the heat treatment process S6 and the order of the manufacturing process.
各工程の概要を説明する。各工程は、代表的な例を示すものであって、必要に応じて適宜変更や追加を行うことができる。 The outline of each process will be described. Each process shows a typical example, and can be changed or added as necessary.
[バー材切断工程S1]
鍛造重量に基づいて所定長さで切断し、ビレットを製作する。
[Bar material cutting step S1]
A billet is manufactured by cutting at a predetermined length based on the forging weight.
[球状化焼なまし工程S2]
冷間鍛造において通常行われるもので、球状化焼なましを施すことにより、冷間鍛造の際の材料流動性(変形能)を向上させる。球状化焼なましの処理時間を短縮するために、ビレットを据え込み加工し、加工ひずみを与える場合がある。
[Spheroidizing annealing step S2]
It is normally performed in cold forging, and improves the material fluidity (deformability) during cold forging by applying spheroidizing annealing. In order to shorten the processing time of spheroidizing annealing, a billet may be upset and processing distortion may be applied.
[ボンデ処理工程S3]
鍛造金型の寿命向上や鍛造性を向上するために、ビレットに潤滑性を高めるボンデ処理を施す。
[Bonde treatment process S3]
In order to improve the life of the forging die and forgeability, the billet is subjected to a bondage treatment that enhances lubricity.
[冷間鍛造工程S4]
鍛造金型のキャビティ内にビレットを投入し、ビレットを塑性加工により金型に充足させる。これにより、ボス部とボス部内周面並びに脚軸が形成されたトリポード部材の冷間鍛造品が得られる。
[Cold forging process S4]
The billet is put into the cavity of the forging die, and the billet is filled into the die by plastic working. Thereby, the cold forging goods of the tripod member in which the boss | hub part, the boss | hub part inner peripheral surface, and the leg axis | shaft were formed are obtained.
[旋削加工工程S5]
冷間鍛造品から脚軸の外径面、止め輪溝、根元部、端面、内周面および面取り部を機械加工する。
[Turning process S5]
The outer diameter surface of the leg shaft, the retaining ring groove, the root portion, the end surface, the inner peripheral surface and the chamfered portion are machined from the cold forged product.
[熱処理工程S5]
等速自在継手の内方部材は、強度を要求されることから、浸炭焼入焼戻しを施して硬度を高める。本実施形態では、局部的に浸炭を抑制した浸炭焼入焼戻しにより、スプライン形成部を一般的なブローチ加工が可能な硬度を有する不完全焼入部とし、このスプライン形成部を除いた表面は焼入部を形成させる。
[Heat treatment step S5]
Since the inner member of the constant velocity universal joint is required to have strength, the hardness is increased by carburizing, quenching and tempering. In the present embodiment, by carburizing quenching and tempering that locally suppresses carburization, the spline forming portion is an incompletely quenched portion having a hardness capable of general broaching, and the surface excluding the spline forming portion is a quenched portion. To form.
[ブローチ加工工程S7]
熱処理完了品の内周面にブローチ加工してスプラインを形成する。
[Broach processing step S7]
A spline is formed by broaching the inner peripheral surface of the heat-treated product.
[研削加工工程S8]
転動体の軌道面となる脚軸の外径面を研削加工で仕上げる。
[Grinding process S8]
The outer diameter surface of the leg shaft that becomes the raceway surface of the rolling element is finished by grinding.
本製造工程の内、バー材切断工程S1〜旋削加工工程S5および研削加工工程S8は、従来と同じである。 Among the manufacturing steps, the bar material cutting step S1 to the turning step S5 and the grinding step S8 are the same as the conventional ones.
本実施形態では、図4に示すスプライン加工前のトリポード部材3の旋削完了品3’を熱処理工程S6に投入する。旋削完了品3’は、具体的には、旋削加工工程S5において、冷間鍛造品(図示省略)から脚軸3b’の外径面15、止め輪溝16、根元部17、端面18、内周面12および面取り部19が旋削加工されている。 In the present embodiment, the turning completed product 3 ′ of the tripod member 3 before spline processing shown in FIG. 4 is put into the heat treatment step S 6. Specifically, in the turning process S5, the turning completed product 3 ′ is obtained from the cold forging product (not shown) to the outer diameter surface 15, the retaining ring groove 16, the root portion 17, the end surface 18, the inner surface of the leg shaft 3b ′. The peripheral surface 12 and the chamfered portion 19 are turned.
次に、熱処理工程S6を図5および図6に基づいて説明する。熱処理として浸炭処理を施す。トリポード部材3の内周のスプライン形成部13sの硬度を局部的に低下させて、一般的なブローチ加工が可能な硬度を有する不完全焼入部を得るために、スプライン形成部13sへの浸炭を抑制する。局部的に浸炭を抑制するには、例えば、浸炭炉に処理品(旋削完了品3’)を投入する際に、処理品の内周の径に近い径の浸炭抑制棒に串刺しにし、炭素の侵入を抑制することにより得ることができる。 Next, heat treatment process S6 is demonstrated based on FIG. 5 and FIG. Carburizing is performed as a heat treatment. In order to locally reduce the hardness of the spline forming portion 13s on the inner periphery of the tripod member 3 and obtain an incompletely hardened portion having a hardness capable of general broaching, the carburization to the spline forming portion 13s is suppressed. To do. In order to suppress carburizing locally, for example, when a processed product (turned product 3 ′) is put into a carburizing furnace, a carburizing suppression rod having a diameter close to the inner diameter of the processed product is skewered, and carbon It can be obtained by suppressing intrusion.
局部的に浸炭を抑制した浸炭焼入焼戻しの具体例を図5に基づいて説明する。図示のように、トリポード部材3の旋削完了品3’を二点鎖線で示す部分を含めて多数(例えば、十数個)積み重ねて浸炭抑制棒20に串刺し状態にし、この浸炭抑制棒20を多数(例えば、十数本)のセットにし、二点鎖線で図示した平網21に固定し、この平網21を適宜段数(例えば、3段)重ねて、その状態で浸炭焼入焼戻しする。浸炭抑制棒20は、耐熱性のステンレス鋼製が好ましく、浸炭抑制棒20は、旋削完了品3’の串刺し作業性も考慮して、内周面の径より若干小さい外径に設定する。図5では、旋削完了品3’の内周面と浸炭抑制棒20の外径面との嵌合すきまを省略して図示している。 A specific example of carburizing and quenching and tempering in which carburization is locally suppressed will be described with reference to FIG. As shown in the drawing, a large number (for example, ten or more) of the completed turning products 3 ′ of the tripod member 3 including a portion indicated by a two-dot chain line are stacked and skewed into the carburization suppression rod 20. A set of (for example, a dozen) is fixed to a flat net 21 illustrated by a two-dot chain line, and this flat net 21 is appropriately stacked in a number of stages (for example, three stages) and carburized, quenched, and tempered in that state. The carburization suppression rod 20 is preferably made of heat-resistant stainless steel, and the carburization suppression rod 20 is set to an outer diameter slightly smaller than the diameter of the inner peripheral surface in consideration of skewering workability of the turned product 3 '. In FIG. 5, the fitting clearance between the inner peripheral surface of the turning completed product 3 ′ and the outer diameter surface of the carburization suppressing rod 20 is omitted.
浸炭処理の条件は、浸炭・拡散が950℃で180〜200分で、浸炭・拡散の後、840℃で20〜30分の加熱保持し、その後、100〜120℃の油に焼入れし、焼戻しは150〜180℃で120分の条件が好ましい。当然、処理品のサイズ等が異なれば、適宜処理条件を変える。 Carburizing conditions are carburizing / diffusion at 950 ° C. for 180-200 minutes, carburizing / diffusion, heating and holding at 840 ° C. for 20-30 minutes, and then quenching and tempering in oil at 100-120 ° C. Is preferably 120 to 180 ° C. for 120 minutes. Of course, if the size of the processed product is different, the processing conditions are appropriately changed.
上記の状態で浸炭焼入焼戻しすると、旋削完了品3’の内周面12は、その径に近い外径の浸炭抑制棒20が嵌合されているので、炭素の侵入を抑制することができる。ただし、旋削完了品3’のボス部3a’の両端面18は、内周面12の軸方向中央部スプライン部より炭素が侵入しやすいため硬度が増加する。 When carburizing, quenching and tempering in the above-described state, the carburization suppressing rod 20 having an outer diameter close to the diameter of the inner peripheral surface 12 of the turning-finished product 3 ′ is fitted, so that carbon intrusion can be suppressed. . However, since both ends 18 of the boss 3a 'of the turning completed product 3' are more likely to intrude carbon than the axially central spline of the inner peripheral surface 12, the hardness increases.
図6に浸炭焼入焼戻し後のトリポード部材3’の状態を示す。図6(a)はトリポード部材3’の部分的な縦断面を示し、図6(b)は、図6(a)のG部の金属組織を示す。図6(a)に示すように、トリポード部材3の熱処理完了品3’の内周のスプライン形成部13sを除いた表面、すなわち、クロスハッチングを施した表面にスプライン部より炭素濃度の高い焼入部Hが形成されている。焼入部Hは、脚軸3b’の外径面15、止め輪溝16、根元部17、ボス部3a’の外表面および端面18に形成され、焼入部Hは面取り部19の手前で留まっている。浸炭は拡散現象のため、焼入部Hと面取り部19の境部では、炭素濃度は連続的に変化するものである(急激に変化するものではない)。焼入部Hの表面硬さは、Hv660〜750程度である。表面硬さの測定部位は、ボス部については軸方向中央部で表面から0.2mmであり、脚軸部ついては軌道面の表面から0.2mmである。一方、トリポード部材3の熱処理完了品3’の内周のスプライン形成部13sは、炭素の侵入が抑制され、冷却速度も遅くなるため不完全焼入部Jが形成されている。この不完全焼入部Jは、スプライン形成部13sの内周面12から半径方向にはスプラインの大径(図7参照)を越えて形成されている。 FIG. 6 shows the state of the tripod member 3 ′ after carburizing, quenching and tempering. FIG. 6A shows a partial longitudinal section of the tripod member 3 ′, and FIG. 6B shows the metal structure of the G part in FIG. 6A. As shown in FIG. 6 (a), the surface of the tripod member 3 excluding the spline forming portion 13s on the inner periphery of the heat-treated product 3 ′, that is, a hardened portion having a carbon concentration higher than that of the spline portion on the surface subjected to cross hatching. H is formed. The hardened portion H is formed on the outer diameter surface 15 of the leg shaft 3b ′, the retaining ring groove 16, the root portion 17, the outer surface of the boss portion 3a ′ and the end surface 18, and the hardened portion H stays in front of the chamfered portion 19. Yes. Since the carburization is a diffusion phenomenon, the carbon concentration changes continuously (not abruptly) at the boundary between the quenching portion H and the chamfered portion 19. The surface hardness of the quenching part H is about Hv660-750. The measurement site of the surface hardness is 0.2 mm from the surface at the center in the axial direction for the boss, and 0.2 mm from the surface of the raceway for the leg shaft. On the other hand, in the spline forming portion 13 s on the inner periphery of the heat treated product 3 ′ of the tripod member 3, the intrusion of carbon is suppressed and the cooling rate is also slowed, so that an incompletely quenched portion J is formed. The incompletely hardened portion J is formed beyond the large diameter of the spline (see FIG. 7) in the radial direction from the inner peripheral surface 12 of the spline forming portion 13s.
内周のスプライン形成部13sの金属組織を図6(b)に示す。内周面12から厚さIの部分が浸炭異常層である。浸炭異常層の厚さIは、浸炭時間が長くなるほど厚くなるが、本実施形態のトリポード部材では10〜25μm程度である。SCM420材、SCr420材などの浸炭用鋼を浸炭焼入焼戻しした場合、表層部に浸炭異常層という軟質の組織が形成される。浸炭異常層とは、鋼中の鉄よりも酸化されやすい珪素(Si)、マンガン(Mn)、クロム(Cr)などの合金元素が浸炭中、オーステナイト粒界で優先酸化した粒界酸化物と、この粒界酸化物生成により固溶合金元素が低下して焼入れ中に生じる不完全焼入層とからなり、これを本明細書および特許請求の範囲において浸炭異常層という。 FIG. 6B shows the metal structure of the inner peripheral spline forming portion 13s. A portion of thickness I from the inner peripheral surface 12 is a carburizing abnormal layer. The thickness I of the carburizing abnormal layer becomes thicker as the carburizing time becomes longer, but is about 10 to 25 μm in the tripod member of the present embodiment. When carburizing steel such as SCM420 material or SCr420 material is carburized, quenched, and tempered, a soft structure called a carburized abnormal layer is formed in the surface layer portion. The carburized abnormal layer is a grain boundary oxide in which alloy elements such as silicon (Si), manganese (Mn), and chromium (Cr), which are more easily oxidized than iron in steel, are preferentially oxidized at the austenite grain boundary during carburizing, This grain boundary oxide formation causes a solid solution alloy element to decrease and an incompletely hardened layer generated during quenching, which is referred to as an abnormal carburizing layer in the present specification and claims.
図7にブローチ加工工程S7を経たトリポード部材3を示す。内周のスプライン形成部13sは、不完全焼入部Jが形成されており、一般的なブローチ加工が適用可能な硬度になっている。具体的には、スプライン13の大径の表面硬さをHv230以上でHv390以下とすることが好ましい。さらに好ましくはHv260以上でHv340以下としている。スプライン13の大径の表面硬さがHv390を越えると、ブローチの寿命が著しく低下すると共にブローチの強度も低下する。一方、表面硬さがHv230未満では、スプライン13の強度の低下を招き、また、浸炭作業面では、浸炭の拡散を完全に防止する必要が生じるので、大掛かりな治工具が必要となり、生産性の低下とコストの増加を招く。表面硬さの測定部位は、スプライン軸方向中央の円周方向断面の大径表面から0.2mmである。スプライン形成部13sをブローチ加工が可能な硬度とし浸炭後にブローチ加工することにより、真円度の高いピッチ円P(図2参照)を有するスプラインを形成することができる。これにより、シャフト11のスプライン14(図1参照)と嵌合してトルクを伝達するとき、スプライン13、14各歯の応力が均一になり、その結果、スプライン13、14への作用応力を低下させることができる。 FIG. 7 shows the tripod member 3 that has undergone the broaching step S7. The inner peripheral spline forming portion 13s has an incompletely hardened portion J, and has a hardness applicable to general broaching. Specifically, the surface hardness of the large diameter of the spline 13 is preferably Hv 230 or more and Hv 390 or less. More preferably, it is set to Hv260 or more and Hv340 or less. When the surface hardness of the large diameter of the spline 13 exceeds Hv390, the life of the broach is remarkably reduced and the strength of the broach is also reduced. On the other hand, when the surface hardness is less than Hv230, the strength of the spline 13 is reduced, and on the carburizing work surface, it is necessary to completely prevent the diffusion of carburizing. Decreasing and increasing costs. The surface hardness measurement site is 0.2 mm from the large-diameter surface of the circumferential section at the center of the spline axis direction. Splines having pitch circles P (see FIG. 2) with high roundness can be formed by setting the spline forming portion 13s to a hardness capable of broaching and performing broaching after carburizing. As a result, when the torque is transmitted by being engaged with the spline 14 (see FIG. 1) of the shaft 11, the stress of each tooth of the spline 13, 14 becomes uniform, and as a result, the acting stress on the spline 13, 14 is reduced. Can be made.
また、前述したように、浸炭異常層の厚さIは10〜25μm程度であるので、スプライン13のブローチ加工により、トリポード部材3の破壊の起点となるスプライン13の歯底(大径)の表面の浸炭異常層は除去され、少なくともスプライン大径の表面は浸炭異常層のない金属組織となっている。したがって、高強度でかつ強度のバラツキの小さなトリポード部材3を実現することができる。同時に、当該トリポード部材3に嵌合されるシャフト11の強度を向上させることができる。なお、ブローチ加工の際、トリポード部材3の内周面12は切削しないので、内周面12には浸炭異常層は残存するが、トルク負荷時の破壊の起点となる部位ではないので、問題は生じない。 Further, as described above, since the thickness I of the carburizing abnormal layer is about 10 to 25 μm, the surface of the tooth bottom (large diameter) of the spline 13 that becomes the starting point of the breakage of the tripod member 3 by broaching the spline 13. The carburized abnormal layer is removed, and at least the surface of the large spline diameter has a metal structure having no carburized abnormal layer. Therefore, the tripod member 3 having high strength and small strength variation can be realized. At the same time, the strength of the shaft 11 fitted to the tripod member 3 can be improved. In addition, since the inner peripheral surface 12 of the tripod member 3 is not cut during broaching, a carburizing abnormal layer remains on the inner peripheral surface 12, but it is not a starting point of breakage at the time of torque load. Does not occur.
次に、第2の実施形態のトリポード型等速自在継手のトリポード部材を図8に基づいて説明する。図8(a)は、トリポード部材の部分的な縦断面図であり、図8(b)はトリポード部材の正面図である。このトリポード部材3は、ダブルローラタイプのトリポード型等速自在継手に組込まれるものである。第1の実施形態と同様の機能を有する箇所には同一の符号を付して重複説明を省略する。 Next, the tripod member of the tripod type constant velocity universal joint according to the second embodiment will be described with reference to FIG. Fig.8 (a) is a partial longitudinal cross-sectional view of a tripod member, FIG.8 (b) is a front view of a tripod member. The tripod member 3 is incorporated into a double roller type tripod type constant velocity universal joint. Parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
本実施形態のトリポード部材3には、図8(a)に二点鎖線で示すようにダブルローラタイプのローラカセット22が装着される。トルク伝達要素としてのローラカセット22は、外側ローラ4、内側リング23および転動体5から構成され、外側ローラ4にワッシャ24を装着して一体ユニットとしている。トリポード部材3の脚軸3bの横断面が略楕円形状に形成されており、この脚軸3bにローラカセット22の内側リング23が首振り自在に装着されている。本実施形態では、脚軸3bの外径面15は、トルク伝達要素としての内側リング23の内径面と嵌合し転がり運動を含んだ支承形態となっており、この外径面15を本明細書および特許請求の範囲において軌道面という。外側ローラ4は、外側継手部材のローラ案内面(図示省略)に回転自在に収容される。このダブルローラタイプのトリポード型等速自在継手は、外側ローラ4が外側継手部材のローラ案内面に平行に案内されるので、軸方向の誘起スラストやスライド抵抗を低減し低振動を実現する。 A double roller type roller cassette 22 is attached to the tripod member 3 of the present embodiment as shown by a two-dot chain line in FIG. The roller cassette 22 as a torque transmission element is composed of an outer roller 4, an inner ring 23 and a rolling element 5, and a washer 24 is attached to the outer roller 4 to form an integrated unit. The cross section of the leg shaft 3b of the tripod member 3 is formed in a substantially elliptical shape, and the inner ring 23 of the roller cassette 22 is swingably mounted on the leg shaft 3b. In the present embodiment, the outer diameter surface 15 of the leg shaft 3b is fitted to the inner diameter surface of the inner ring 23 as a torque transmission element and includes a rolling motion. In the description and claims, it is called the raceway surface. The outer roller 4 is rotatably accommodated on a roller guide surface (not shown) of the outer joint member. In the double roller type tripod type constant velocity universal joint, since the outer roller 4 is guided in parallel with the roller guide surface of the outer joint member, axial induced thrust and slide resistance are reduced, and low vibration is realized.
本実施形態のトリポード部材3においても、スプライン形成部13sは不完全焼入部Jで形成され、少なくともスプライン13の大径の表面を浸炭異常層のない金属組織となっており、スプライン形成部13sを除いた表面はスプライン部より炭素濃度の高い焼入部(図示省略)となっている。そして、浸炭焼入焼戻し後のブローチ加工により、トラニオン部材3のスプライン13は熱処理変形がなく、真円度の高いピッチ円で形成され、このスプライン13にシャフトのスプラインを嵌合しトルクを伝達するとき、各スプラインの応力は可及的に均一になる。また、ブローチ加工により浸炭異常層が除去されるので、トリポード部材3の疲労強度が向上し、同時に、トリポード部材3に嵌合されるシャフトの強度を向上させることができる。その他、製造工程や、内周面12に形成されたスプライン13およびスプライン形成部13sの金属組織、寸法精度、強度特性などの詳細については、前述した第1の実施形態と同様であるので、重複説明を省略する。 Also in the tripod member 3 of the present embodiment, the spline forming portion 13s is formed by the incompletely quenched portion J, and at least the surface of the large diameter of the spline 13 has a metal structure having no carburizing abnormal layer. The removed surface is a hardened portion (not shown) having a higher carbon concentration than the spline portion. And by broaching after carburizing, quenching and tempering, the spline 13 of the trunnion member 3 is not deformed by heat treatment and is formed in a pitch circle having a high roundness, and the shaft spline is fitted to the spline 13 to transmit torque. Sometimes the stress in each spline is as uniform as possible. Moreover, since the carburizing abnormal layer is removed by broaching, the fatigue strength of the tripod member 3 can be improved, and at the same time, the strength of the shaft fitted to the tripod member 3 can be improved. In addition, the details of the manufacturing process and the metal structure, dimensional accuracy, strength characteristics, and the like of the spline 13 and spline forming portion 13s formed on the inner peripheral surface 12 are the same as those in the first embodiment described above, so Description is omitted.
本発明の第3の実施形態の等速自在継手の内方部材について図9〜11に基づいて説明する。図9および図10に示す等速自在継手は、固定式等速自在継手の一種であるツェッパ型等速自在継手である。この等速自在継手31は、外側継手部材32、内方部材としての内側継手部材33、トルク伝達要素としてのボール34およびケージ35を主な構成とする。外側継手部材32の球状内周面38には6本のトラック溝36が円周方向等間隔に、かつ軸方向に沿って形成されている。内側継手部材33の球状外周面39には、外側継手部材32のトラック溝36と対向するトラック溝37が円周方向等間隔に、かつ軸方向に沿って形成されている。外側継手部材32のトラック溝36と内側継手部材33のトラック溝37との間にトルクを伝達する6個のボール34が介在されている。トラック溝36、37がボール34の軌道面を形成する。外側継手部材32の球状内周面38と内側継手部材33の球状外周面39の間に、ボール34を保持するケージ35が配置されている。内側継手部材33の内周面45にはスプライン46が形成され、このスプライン46にシャフト42のスプライン47が嵌合され、止め輪44により軸方向に固定されている。外側継手部材32の外周と、内側継手部材33にスプライン連結されたシャフト42の外周とをブーツ43で覆い、継手内部には、潤滑剤としてグリースが封入されている。 An inward member of the constant velocity universal joint according to the third embodiment of the present invention will be described with reference to FIGS. The constant velocity universal joint shown in FIGS. 9 and 10 is a Rzeppa type constant velocity universal joint which is a kind of fixed type constant velocity universal joint. The constant velocity universal joint 31 mainly includes an outer joint member 32, an inner joint member 33 as an inward member, a ball 34 and a cage 35 as torque transmitting elements. Six track grooves 36 are formed on the spherical inner peripheral surface 38 of the outer joint member 32 at equal intervals in the circumferential direction and along the axial direction. On the spherical outer peripheral surface 39 of the inner joint member 33, track grooves 37 facing the track grooves 36 of the outer joint member 32 are formed at equal intervals in the circumferential direction and along the axial direction. Six balls 34 for transmitting torque are interposed between the track grooves 36 of the outer joint member 32 and the track grooves 37 of the inner joint member 33. The track grooves 36 and 37 form the track surface of the ball 34. A cage 35 for holding the ball 34 is disposed between the spherical inner peripheral surface 38 of the outer joint member 32 and the spherical outer peripheral surface 39 of the inner joint member 33. A spline 46 is formed on the inner peripheral surface 45 of the inner joint member 33, and a spline 47 of the shaft 42 is fitted into the spline 46 and is fixed in the axial direction by a retaining ring 44. The outer periphery of the outer joint member 32 and the outer periphery of the shaft 42 splined to the inner joint member 33 are covered with a boot 43, and grease is enclosed as a lubricant inside the joint.
図9に示すように、外側継手部材32の球状内周面38と内側継手部材33の球状外周面39の曲率中心は、いずれも、継手の中心Oに形成されている。また、保持器35の球状外周面40および球状内周面41の曲率中心も継手の中心Oに形成されている。これに対して、外側継手部材32のトラック溝36の曲率中心Aと、内側継手部材33のトラック溝37の曲率中心Bとは、継手の中心Oに対して軸方向に等距離オフセットされている。これにより、継手が作動角をとった場合、外側継手部材32と内側継手部材33の両軸線がなす角度を二等分する平面上にボール34が常に案内され、二軸間で等速に回転が伝達されることになる。 As shown in FIG. 9, the centers of curvature of the spherical inner peripheral surface 38 of the outer joint member 32 and the spherical outer peripheral surface 39 of the inner joint member 33 are both formed at the center O of the joint. Further, the centers of curvature of the spherical outer peripheral surface 40 and the spherical inner peripheral surface 41 of the cage 35 are also formed at the center O of the joint. On the other hand, the center of curvature A of the track groove 36 of the outer joint member 32 and the center of curvature B of the track groove 37 of the inner joint member 33 are offset by an equal distance in the axial direction with respect to the center O of the joint. . As a result, when the joint takes an operating angle, the ball 34 is always guided on a plane that bisects the angle formed by the two axes of the outer joint member 32 and the inner joint member 33, and rotates at a constant speed between the two axes. Will be transmitted.
図11に内側継手部材33を拡大した正面図を示す。内側継手部材33も、前述した第1の実施形態のトリポード部材とほぼ同様の工程を経て製作される。内側継手部材33は、トラック溝形成部位Eと球状外周面形成部位Fからなり、肉厚が周方向で変化する。この内側継手部材33においても、スプライン形成部46sは不完全焼入部で形成され、少なくともスプライン46の大径の表面は浸炭異常層のない金属組織となっており、スプライン形成部46sを除いた表面はスプライン部より炭素濃度の高い焼入部となっている。 FIG. 11 shows an enlarged front view of the inner joint member 33. The inner joint member 33 is also manufactured through substantially the same process as the tripod member of the first embodiment described above. The inner joint member 33 includes a track groove forming portion E and a spherical outer peripheral surface forming portion F, and the thickness changes in the circumferential direction. Also in this inner joint member 33, the spline forming portion 46s is formed by an incompletely hardened portion, and at least the large diameter surface of the spline 46 has a metal structure without a carburizing abnormal layer, and the surface excluding the spline forming portion 46s. Is a hardened part with a higher carbon concentration than the spline part.
内側継手部材33のスプライン46は、熱処理変形がなく、肉厚の厚い球状外周面形成部位Fと肉厚の薄いトラック溝形成部位Eの全周にわたって真円度の高いピッチ円Pで形成され、このスプライン46にシャフト42のスプライン47を嵌合しトルクを伝達するとき、各スプライン46、47の応力は可及的に均一になる。また、ブローチ加工により浸炭異常層が除去されるので、内側継手部材33の疲労強度が向上し、同時に、内側継手部材33に嵌合されるシャフト42の強度を向上させることができる。その他、製造工程や、内周面45に形成されたスプライン46およびスプライン形成部46sの金属組織、寸法精度、強度特性などの詳細については、前述した第1の実施形態と同様であるので、重複説明を省略する。 The spline 46 of the inner joint member 33 is not deformed by heat treatment, and is formed by a pitch circle P having a high roundness over the entire circumference of the thick spherical outer peripheral surface forming portion F and the thin track groove forming portion E. When the spline 47 of the shaft 42 is fitted to the spline 46 and torque is transmitted, the stress of each spline 46, 47 becomes as uniform as possible. Further, since the carburizing abnormal layer is removed by broaching, the fatigue strength of the inner joint member 33 is improved, and at the same time, the strength of the shaft 42 fitted to the inner joint member 33 can be improved. In addition, the details of the manufacturing process and the metal structure, dimensional accuracy, strength characteristics, and the like of the spline 46 and the spline forming portion 46s formed on the inner peripheral surface 45 are the same as those in the first embodiment described above, and thus overlap. Description is omitted.
本発明の第4の実施形態の等速自在継手の内方部材を図12に基づいて説明する。図12(a)は内方部材としての内側継手部材の縦断面図であり、図12(b)は、図12(a)の軸方向中央部での横断面図である。この内側継手部材33は、摺動式等速自在継手の一種であるダブルオフセット型等速自在継手の内側継手部材である。この内側継手部材33の球状外周面39には直線状のトラック溝37が円周方向等間隔に、かつ軸方向に沿って形成されている。トラック溝37がボールの軌道面を形成する。この内側継手部材33も、前述した第1の実施形態のトリポード部材とほぼ同様の工程を経て製作される。内側継手部材33は、トラック溝形成部位Eと球状外周面形成部位Fからなり、肉厚が周方向で変化する。 An inner member of the constant velocity universal joint according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 12A is a longitudinal sectional view of an inner joint member as an inward member, and FIG. 12B is a transverse sectional view at a central portion in the axial direction of FIG. The inner joint member 33 is an inner joint member of a double offset type constant velocity universal joint which is a kind of sliding type constant velocity universal joint. Linear track grooves 37 are formed on the spherical outer peripheral surface 39 of the inner joint member 33 at equal intervals in the circumferential direction and along the axial direction. The track groove 37 forms the raceway surface of the ball. The inner joint member 33 is also manufactured through substantially the same process as the tripod member of the first embodiment described above. The inner joint member 33 includes a track groove forming portion E and a spherical outer peripheral surface forming portion F, and the thickness changes in the circumferential direction.
この内側継手部材33においても、スプライン形成部46sは不完全焼入部Jで形成され、少なくともスプライン46の大径の表面は浸炭異常層のない金属組織となっており、スプライン形成部46sを除いた表面はスプライン部より炭素濃度の高い焼入部(図示省略)となっている。そして、浸炭焼入焼戻し後のブローチ加工により、内側継手部材33のスプライン46は熱処理変形がなく、真円度の高いピッチ円で形成され、このスプライン46にシャフトのスプラインを嵌合しトルクを伝達するとき、各スプラインの応力は可及的に均一になる。また、ブローチ加工により浸炭異常層が除去されるので、内側継手部材33の疲労強度が向上し、同時に、内側継手部材33に嵌合されるシャフトの強度を向上させることができる。その他、製造工程や、内周面45に形成されたスプライン46およびスプライン形成部46sの金属組織、寸法精度、強度特性などの詳細については、前述した第1の実施形態と同様であるので、重複説明を省略する。 Also in this inner joint member 33, the spline forming portion 46s is formed by the incompletely quenched portion J, and at least the large-diameter surface of the spline 46 has a metal structure having no carburizing abnormal layer, and the spline forming portion 46s is excluded. The surface is a hardened portion (not shown) having a higher carbon concentration than the spline portion. Then, by broaching after carburizing, quenching and tempering, the spline 46 of the inner joint member 33 is not deformed by heat treatment and is formed in a highly circular pitch circle, and the shaft spline is fitted to the spline 46 to transmit torque. When doing so, the stress of each spline becomes as uniform as possible. Further, since the carburizing abnormal layer is removed by broaching, the fatigue strength of the inner joint member 33 is improved, and at the same time, the strength of the shaft fitted to the inner joint member 33 can be improved. In addition, the details of the manufacturing process and the metal structure, dimensional accuracy, strength characteristics, and the like of the spline 46 and the spline forming portion 46s formed on the inner peripheral surface 45 are the same as those in the first embodiment described above, and thus overlap. Description is omitted.
図13は、第3の実施形態の内側継手部材を組込んだ固定式のツェッパ型等速自在継手31と第1の実施形態のトリポード部材を組み込んだ摺動式のトリポード型等速自在継手1を適用した自動車のフロント用ドライブシャフト50を示す。ツェッパ型等速自在継手31の内側継手部材33は中空シャフト51の一端にスプライン連結され、他端にはトリポード型等速自在継手1のトリポード部材3がスプライン連結されている。ツェッパ型等速自在継手31の外周面と中空シャフト51の外周面との間、およびトリポード型等速自在継手1の外周面とシャフト51の外周面との間に、それぞれ蛇腹状ブーツ43、52がブーツバンド53a、53b、53c、53dにより締付け固定されている。継手内部には、潤滑剤としてのグリースが封入されている。 FIG. 13 shows a sliding type tripod type constant velocity universal joint 1 incorporating the fixed type Zepper type constant velocity universal joint 31 incorporating the inner joint member of the third embodiment and the tripod member of the first embodiment. The front drive shaft 50 of the motor vehicle to which is applied is shown. The inner joint member 33 of the Rzeppa constant velocity universal joint 31 is splined to one end of the hollow shaft 51, and the tripod member 3 of the tripod type constant velocity universal joint 1 is splined to the other end. Bellows-shaped boots 43, 52 between the outer peripheral surface of the Rzeppa constant velocity universal joint 31 and the outer peripheral surface of the hollow shaft 51 and between the outer peripheral surface of the tripod type constant velocity universal joint 1 and the outer peripheral surface of the shaft 51, respectively. Is fastened and fixed by boot bands 53a, 53b, 53c, 53d. Grease as a lubricant is sealed inside the joint.
内側継手部材33およびトリポード部材3のスプラインは熱処理変形がなく、真円度の高いピッチ円で形成されているので、前述したように嵌合する中空シャフトのスプラインとの間の応力は可及的に均一になる。また、ブローチ加工により浸炭異常層が除去されるので、内側継手部材33の疲労強度が向上し、同時に、内側継手部材33に嵌合される中空シャフト51の強度を向上させることができる。これにより、高強度の自動車用ドライブシャフト50を実現することができる。 Since the splines of the inner joint member 33 and the tripod member 3 are not deformed by heat treatment and are formed by pitch circles having a high roundness, the stress between the splines of the hollow shafts to be fitted is as much as possible. It becomes uniform. Further, since the carburizing abnormal layer is removed by broaching, the fatigue strength of the inner joint member 33 is improved, and at the same time, the strength of the hollow shaft 51 fitted to the inner joint member 33 can be improved. Thereby, the high-strength automobile drive shaft 50 can be realized.
さらに、前述した製造方法についての実施形態の変形例として、ブローチの寿命がより向上する加工工程を種々検討した結果、クロム鋼(SCr415)のバー材を切断、球状化焼なまし、ボンデ処理、冷間鍛造、荒旋削、熱処理、内周部仕上げ旋削、ブローチ加工、脚軸部研削という工程であることが分かった。 Furthermore, as a modification of the embodiment of the manufacturing method described above, as a result of various investigations of processing steps that further improve the life of the broach, the bar material of chrome steel (SCr415) is cut, spheroidized, annealed, It was found that the processes were cold forging, rough turning, heat treatment, inner peripheral finishing turning, broaching, and leg shaft grinding.
熱処理後の内周部仕上げ旋削は、ボス部の両端、すなわち、スプラインの軸方向の両端面と内周部仕上げ旋削する。これは、ボス部の両端面は、内周部の軸方向中央部より炭素が侵入しやすく、表面硬さが増加することに対処するためである。また、内周部は、浸炭焼入焼戻し後、真円度が悪化する。この変形を残した状態でブローチ加工するとブローチの歯の寿命が低下する。したがって、仕上げ旋削で硬化部の除去と内周部の真円度の向上により、ブローチの寿命がより向上することが分かった。本発明の製造方法についての実施形態は、図3に示す熱処理工程S6とブローチ加工工程S7との間に、上記のような内周面仕上げ旋削加工工程を追加したものも当然含むものである。 In the inner peripheral finishing turning after the heat treatment, both ends of the boss part, that is, both end faces in the axial direction of the spline and inner peripheral finishing turning are performed. This is because both end surfaces of the boss portion are more likely to intrude carbon than the axially central portion of the inner peripheral portion, and cope with the increase in surface hardness. Further, the roundness of the inner peripheral portion deteriorates after carburizing, quenching and tempering. If broaching is performed with this deformation left, the life of the broach teeth will be reduced. Therefore, it was found that the life of the broach is further improved by removing the hardened portion and improving the roundness of the inner peripheral portion by finishing turning. The embodiment of the manufacturing method of the present invention naturally includes a case where an inner peripheral surface finishing turning process as described above is added between the heat treatment step S6 and the broaching step S7 shown in FIG.
本発明の製造方法についての実施形態によれば、ブローチ加工は、通常の高速度工具鋼(SKH55やSKH51)や、これに相当する鋼材(モリブデン系高速度工具鋼)を熱処理しHRC63以上に焼入焼戻し後、仕上げ加工した一般的なブローチで加工することができる。 According to the embodiment of the manufacturing method of the present invention, broaching is performed by heat-treating ordinary high-speed tool steel (SKH55 or SKH51) or a corresponding steel material (molybdenum-based high-speed tool steel) to HRC63 or higher. After quenching and tempering, it can be processed with a finished general broach.
本発明の実施例および比較例を以下に説明する。第1の実施形態のトリポード部材3を実施例1は、クロムモリブデン鋼(SCM420)のバー材を、実施形態の製造工程である切断、球状化焼なまし、ボンデ処理、冷間鍛造、旋削、浸炭焼入焼戻し、ブローチ加工、脚軸の研削を行って製作した。スプラインはJIS B 1603の平底スプラインで、主要諸元は、ダイヤメトラルピッチ:32/64、圧力角:37.5°、歯数:30、大径:25.034mm、小径:23.19mm、ピッチ円直径(PCD):23.813mmとした。熱処理条件としては、トリポード部材の旋削完了品を浸炭抑制棒に積み重ねて串刺し状態にし、950℃で200分の浸炭・拡散の後、840℃で23分の加熱保持後、110℃の油に焼入れた。その後、160℃で120分の焼戻しを行った。 Examples of the present invention and comparative examples will be described below. Example 1 of the tripod member 3 of the first embodiment is a bar material of chrome molybdenum steel (SCM420), cutting, spheroidizing annealing, bonding process, cold forging, turning, which are the manufacturing steps of the embodiment, It was manufactured by carburizing, quenching and tempering, broaching, and grinding the leg shaft. The spline is a flat bottom spline of JIS B 1603. The main specifications are: Diametral pitch: 32/64, pressure angle: 37.5 °, number of teeth: 30, large diameter: 25.03 mm, small diameter: 23.19 mm, pitch Circular diameter (PCD): 23.813 mm. As heat treatment conditions, the finished product of tripod member is stacked on carburization suppression rods and skewered, carburized and diffused at 950 ° C for 200 minutes, held at 840 ° C for 23 minutes, and then quenched into oil at 110 ° C. It was. Thereafter, tempering was performed at 160 ° C. for 120 minutes.
実施例2は、クロム鋼(SCr420)のバー材を用いて、実施例1と同じ製造工程で製作した。平底スプラインの諸元および熱処理条件は、実施例1と同じである。 Example 2 was manufactured in the same manufacturing process as Example 1 using a bar material of chromium steel (SCr420). The specifications of the flat bottom spline and the heat treatment conditions are the same as in Example 1.
実施例3は、実施例2のJIS B 1603の平底スプラインを丸底スプラインに変更した点のみが異なる。 Example 3 is different only in that the flat bottom spline of JIS B 1603 of Example 2 is changed to a round bottom spline.
比較例1は、クロムモリブデン鋼(SCM420)のバー材を、従来の製造工程である切断、球状化焼なまし、ボンデ処理、冷間鍛造、旋削、ブローチ加工、浸炭焼入焼戻し、脚軸の研削を行って製作した。熱処理条件は、通常の浸炭焼入焼戻しで、実施例1と同じ温度条件および時間条件とした。スプライン歯の形状および諸元は、実施例1および実施例2と同じである。 In Comparative Example 1, a chromium-molybdenum steel (SCM420) bar material was cut, spheroidized, bonded, cold forged, turned, broached, carburized, quenched, and tempered, which are conventional manufacturing processes. Made by grinding. The heat treatment conditions were normal carburizing quenching and tempering, and the same temperature conditions and time conditions as in Example 1. The shape and specifications of the spline teeth are the same as those in the first and second embodiments.
実施例と比較例の特性と疲労試験結果を表1に示す。ただし、疲労試験は、自動車規格(JASO C 304−89:自動車の駆動軸用等速ジョイント 1989年3月31日制定 社団法人 自動車技術会 発行)の3ページの表3中の等速ジョイントの呼び22.2のジョイントに作動角0°の状態で1504Nmの荷重を負荷して実施した。表1の表面硬さの測定部位は、歯面部については軸方向中央部で表面から0.2mmであり、脚軸部ついては軌道面の表面から0.2mmである。
疲労試験結果より、比較例1の破断回数L50(50%破壊確率寿命)を基準として、実施例1〜3は大幅に疲労寿命が向上している。モリブデン(Mo)を添加しない低コストのクロム鋼(SCr420)を用いた実施例2でも高強度になることが分かった。また、クロムモリブデン鋼(SCM420)を用いた実施例1よりクロム鋼(SCr420)を用いた実施例2の方が歯面部の硬さが低下するためブローチの寿命が向上することが分かった。 From the fatigue test results, the fatigue life of Examples 1 to 3 is greatly improved based on the number of breaks L 50 (50% probability of fracture life) of Comparative Example 1. It was also found that Example 2 using low-cost chromium steel (SCr420) to which no molybdenum (Mo) was added had high strength. Moreover, it turned out that the life of a broach is improved in Example 2 using chromium steel (SCr420) because the hardness of the tooth surface portion is lower than that in Example 1 using chromium molybdenum steel (SCM420).
実施例3の疲労試験結果より、スプライン歯の形状変更の効果として、平底スプラインよりも丸底スプラインの方が若干疲労強度で有利と考えられる。 From the fatigue test results of Example 3, it is considered that the round bottom spline is slightly more advantageous in fatigue strength than the flat bottom spline as an effect of changing the shape of the spline teeth.
次に、実施例1と比較例1を中空シャフトにスプライン嵌合させた組付け状態での疲労強度を評価するために疲労試験を実施した。中空シャフトは、SAE15B35材の鋼管を用いて、塑性加工と機械加工を行い、高周波焼入れにより硬化させ中空シャフトを製作した。中空シャフトのスプラインの主要諸元は、ダイヤメトラルピッチ:32/64、圧力角:37.5°、歯数:30、大径:24.613mm、小径:22.535mm、ピッチ円直径(PCD):23.813mmとした。スプライン形成部における中空シャフトの内径は10.8mmとした。 Next, a fatigue test was carried out in order to evaluate the fatigue strength in the assembled state in which Example 1 and Comparative Example 1 were spline fitted to the hollow shaft. The hollow shaft was manufactured by performing plastic working and machining using a steel pipe made of SAE15B35, and hardening it by induction hardening to produce a hollow shaft. The main specifications of the hollow shaft spline are: Diametral pitch: 32/64, Pressure angle: 37.5 °, Number of teeth: 30, Large diameter: 24.613 mm, Small diameter: 22.535 mm, Pitch circle diameter (PCD) : 23.813 mm. The inner diameter of the hollow shaft in the spline forming portion was 10.8 mm.
実施例1のトリポード部材と比較例1のトリポード部材を中空シャフトにスプライン嵌合させた中空シャフト組付け体AおよびBの疲労試験結果を表2に示す。疲労試験の荷重は、表1の場合と同じであるが、両振り捩り疲労試験を行った。
疲労試験の結果、比較例1のトリポード部材を組付けた中空シャフト組付け体Bの破断回数L50を基準として、実施例1のトリポード部材を組付けた中空シャフト組付け体Aの疲労強度は大幅に向上することが分かった。また、破断部位はいずれも中空シャフトのスプライン部であった。 Results of the fatigue test, based on the rupture times L 50 of the hollow shaft assembly body B with assembled tripod member of Comparative Example 1, the fatigue strength of the hollow shaft assembly body A is assembled the tripod member of Example 1 It turns out that it improves significantly. Moreover, all the fracture | rupture parts were the spline parts of the hollow shaft.
以上の各実施形態では、固定式等速自在継手としてツェッパ型等速自在継手、摺動式等速自在継手としてダブルオフセット型等速自在継手およびトリポード型等速自在継手の内方部材を示したが、これに限定されるものではない。上記の他に、固定式等速自在継手として、アンダーカットフリー型等速自在継手、カウンタートラック形式の等速自在継手や、摺動式等速自在継手として、クロスグルーブ型等速自在継手、保持器のないデルタ型等速自在継手の内方部材でも適宜実施することができる。また、ボールの個数は6個のものを示したが、これに限定されるものではなく、3〜5個、8個や10個以上でも実施することができる。 In each of the above embodiments, the inner member of the Rzeppa type constant velocity universal joint as the fixed type constant velocity universal joint and the double offset type constant velocity universal joint and the tripod type constant velocity universal joint as the sliding type constant velocity universal joint are shown. However, the present invention is not limited to this. In addition to the above, as a fixed type constant velocity universal joint, an undercut-free type constant velocity universal joint, a counter track type constant velocity universal joint, and as a sliding type constant velocity universal joint, a cross groove type constant velocity universal joint, holding The inner member of a delta type constant velocity universal joint without a vessel can be appropriately implemented. In addition, although the number of balls is six, the present invention is not limited to this, and the number of balls can be 3 to 5, 8, or 10 or more.
また、本発明は前述した実施形態に何ら限定されるものではなく、本発明の要旨を逸脱しない範囲内において、さらに種々の形態で実施し得ることは勿論のことであり、本発明の範囲は、特許請求の範囲によって示され、さらに特許請求の範囲に記載の均等の意味、および範囲内のすべての変更を含む。 The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the spirit of the present invention. All equivalents and equivalents of the claims, and all modifications within the scope of the claims are embraced by the claims.
1 トリポード型等速自在継手
2 外側継手部材
3 トリポード部材
4 球面ローラ(トルク伝達要素)
5 転動体(トルク伝達要素)
6 トラック溝
7 ローラ案内面
11 シャフト
12 内周面
13 スプライン
13s スプライン形成部
15 外径面(軌道面)
31 ツェッパ型等速自在継手
32 外側継手部材
33 内側継手部材
34 ボール(トルク伝達要素)
35 保持器
36 トラック溝(軌道面)
37 トラック溝(軌道面)
42 シャフト
A 曲率中心
B 曲率中心
C 円筒状部位
D 脚軸形成部位
E トラック溝形成部位
H 焼入部
J 不完全焼入部
O 継手の中心
DESCRIPTION OF SYMBOLS 1 Tripod type constant velocity universal joint 2 Outer joint member 3 Tripod member 4 Spherical roller (torque transmission element)
5 Rolling elements (torque transmission elements)
6 Track groove 7 Roller guide surface 11 Shaft 12 Inner peripheral surface 13 Spline 13s Spline forming portion 15 Outer diameter surface (track surface)
31 Rzeppa constant velocity universal joint 32 Outer joint member 33 Inner joint member 34 Ball (torque transmission element)
35 Cage 36 Track groove (track surface)
37 Track groove (track surface)
42 Shaft A Center of curvature B Center of curvature C Cylindrical part D Leg shaft forming part E Track groove forming part H Hardened part J Incompletely hardened part O Joint center
Claims (5)
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JP2012090183A JP5917249B2 (en) | 2012-04-11 | 2012-04-11 | Inner member of constant velocity universal joint and manufacturing method thereof |
PCT/JP2013/060287 WO2013154015A1 (en) | 2012-04-11 | 2013-04-04 | Inner member of constant velocity universal joint and method for producing same |
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JP5917249B2 JP5917249B2 (en) | 2016-05-11 |
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Cited By (3)
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WO2016076051A1 (en) * | 2014-11-11 | 2016-05-19 | Ntn株式会社 | Tripod-type constant velocity universal joint and manufacturing method for tripod member thereof |
JP2018200109A (en) * | 2018-08-24 | 2018-12-20 | Ntn株式会社 | Tripod-type constant velocity universal joint |
KR102201492B1 (en) * | 2019-07-12 | 2021-01-13 | 에코디엠랩 주식회사 | Linear piezoelectric motor |
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JP2007155100A (en) * | 2005-12-08 | 2007-06-21 | Ntn Corp | Outside joint member for constant velocity universal joint |
JP2008284999A (en) * | 2007-05-17 | 2008-11-27 | Ntn Corp | Wheel bearing device |
JP2009541682A (en) * | 2006-07-05 | 2009-11-26 | ノイマイアー テクフォア ホールディング ゲゼルシャフト ミット ベシュレンクテル ハフツング | Torque transmission device |
JP2011094700A (en) * | 2009-10-29 | 2011-05-12 | Ntn Corp | Hollow shaft and constant velocity universal joint |
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JP2003193138A (en) * | 2001-12-26 | 2003-07-09 | Toyota Motor Corp | Method for manufacturing steel part |
JP2007211926A (en) * | 2006-02-10 | 2007-08-23 | Ntn Corp | Inner member of constant velocity universal joint and its manufacturing method |
JP2009085327A (en) * | 2007-09-28 | 2009-04-23 | Ntn Corp | Sliding type constant velocity universal joint and its outer side joint member |
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2013
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Patent Citations (4)
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JP2007155100A (en) * | 2005-12-08 | 2007-06-21 | Ntn Corp | Outside joint member for constant velocity universal joint |
JP2009541682A (en) * | 2006-07-05 | 2009-11-26 | ノイマイアー テクフォア ホールディング ゲゼルシャフト ミット ベシュレンクテル ハフツング | Torque transmission device |
JP2008284999A (en) * | 2007-05-17 | 2008-11-27 | Ntn Corp | Wheel bearing device |
JP2011094700A (en) * | 2009-10-29 | 2011-05-12 | Ntn Corp | Hollow shaft and constant velocity universal joint |
Cited By (4)
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WO2016076051A1 (en) * | 2014-11-11 | 2016-05-19 | Ntn株式会社 | Tripod-type constant velocity universal joint and manufacturing method for tripod member thereof |
JP2016090028A (en) * | 2014-11-11 | 2016-05-23 | Ntn株式会社 | Tripod-type constant velocity universal joint and manufacturing method of tripod member of tripod-type constant velocity universal joint |
JP2018200109A (en) * | 2018-08-24 | 2018-12-20 | Ntn株式会社 | Tripod-type constant velocity universal joint |
KR102201492B1 (en) * | 2019-07-12 | 2021-01-13 | 에코디엠랩 주식회사 | Linear piezoelectric motor |
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WO2013154015A1 (en) | 2013-10-17 |
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