Constant velocity joints and drive shafts comprising constant velocity joints

Abstract

The constant velocity joint includes: an outer race forming multiple outer ball tracks; an inner race forming multiple inner ball tracks corresponding to the outer ball tracks; a ball cage forming multiple windows; and multiple torque-transmitting balls respectively housed in the windows. The outer and inner races are configured to achieve a hinged function that results in relative angular displacement with respect to each other. The inner race is fastened to a connecting shaft of the drive shaft via a ball spline connection structure. The ball spline connection structure includes an outer spline groove, an inner spline groove, a sleeve member, and multiple spline balls housed in sleeve windows formed in the sleeve member. The outer race has a spherical inner circumference with a first diameter, and the diagonal length of the inner race is less than the first diameter.

Description

Technical Field

[0001] This disclosure relates to a constant velocity joint for transmitting driving force in a vehicle and a drive shaft including the constant velocity joint. Background Technology

[0002] As a power transmission component, the constant velocity joint forms part of the drivetrain system, which transmits the driving force generated by the vehicle's power source (such as an internal combustion engine or electric motor) to the wheels. It is well known that constant velocity joints can be designed to transmit rotational driving force while accommodating changes in angular displacement and axial length that occur during vehicle operation.

[0003] Typically, a constant velocity joint (CV joint) is part of a drive shaft or half-shaft. The drive shaft includes a connecting shaft and a pair of CV joints, each attached to either end of the connecting shaft. Of these CV joints, the one located on the inside in the lateral direction of the vehicle is usually called the inner joint, and the one located on the outside is usually called the outer joint. This type of drive shaft is designed to provide angular motion and axial displacement capabilities at the CV joints. A common method to achieve axial displacement in a drive shaft is to configure one of the CV joints (e.g., typically the inner joint) as a structure capable of axial displacement, such as a tripod CV joint. However, the tripod CV joint is structurally and costly compared to the so-called Rzeppa joint.

[0004] Another method for achieving axial displacement in a driveshaft is to apply a ball spline structure to the interconnecting shaft, as disclosed in Korean Patent Registration No. 10-2179859, thereby allowing the interconnecting shaft to have axial displacement capability. Additionally, vehicles may experience lateral vibrations during rapid acceleration, a phenomenon caused by resonance between the axial force generated by the driveshaft (Generated Axial Force, GAF) and the output from the engine or electric motor. Minimizing this phenomenon is one of the key challenges in vehicle design, and methods introduced to address this issue involve using advanced tripod constant velocity joints designed to minimize GAF. However, in tall vehicles, the improvement provided by advanced tripod constant velocity joints is limited. Driveshafts with interconnecting shafts featuring ball spline structures offer a good alternative for reducing this phenomenon and also provide the advantage of allowing for greater height in vehicle design. Furthermore, ball spline structures offer the benefit of providing excellent NVH (noise, vibration, and harshness) performance. However, interconnecting shafts with ball spline structures require a diameter up to 60% larger than that of conventional hollow or solid interconnecting shafts, thus requiring more installation space and posing challenges in vehicle design. Furthermore, connecting shafts with ball spline structures are heavier than conventional shafts, which negatively impacts vehicle fuel or energy efficiency and complicates manufacturing processes, leading to higher production costs. Therefore, a solution is needed that leverages the advantages of ball spline structures while overcoming the aforementioned drawbacks.

[0005] <Prior art documents>

[0006] - Korean Patent Registration No. 10-2179859

[0007] The details described in the background section are provided to enhance understanding of the background and may include information that is not part of the prior art known in the field to which this technology belongs. Summary of the Invention

[0008] The purpose of this invention is to provide a constant velocity joint and a drive shaft including the constant velocity joint, which not only adopts the advantages of a ball spline structure, but also reduces the diameter and weight of the interconnecting shaft, while having a simplified manufacturing process and lower production cost.

[0009] The technical objectives of this invention are not limited to those described above. Other technical objectives not explicitly stated will be understood by those skilled in the art from the following description.

[0010] In an embodiment of the invention, a constant velocity joint configured to be coupled to an interconnecting shaft of a drive shaft includes: an outer race forming a plurality of outer ball tracks; an inner race forming a plurality of inner ball tracks corresponding to the plurality of outer ball tracks; a ball retainer inserted between the outer race and the inner race and forming a plurality of windows; and a plurality of torque-transmitting balls, which are respectively disposed in the windows and in spaces formed by pairs of outer and inner ball tracks. The inner race is coupled to the interconnecting shaft via a ball spline connection structure to achieve length displacement by relative axial displacement along the axial direction of the interconnecting shaft. The ball spline connection structure includes: an outer spline groove provided on the inner race; an inner spline groove provided on the interconnecting shaft corresponding to the outer spline groove; a sleeve member inserted between the inner race and the interconnecting shaft; and a plurality of splined balls disposed in the spaces formed by pairs of outer and inner spline grooves, wherein the splined balls are disposed in sleeve windows formed on the sleeve member. The outer race includes an inner circumferential surface with a spherical surface shape having a first diameter, and the diagonal length of the inner race is less than the first diameter.

[0011] The outer race may include a coupling side and an opening side, and the outer race may also include a recessed space formed to accommodate at least a portion of the end of the interconnect shaft when the interconnect shaft is displaced toward the coupling side.

[0012] Splined balls can be arranged in a row, and when the joint is in a non-hinged state, the row of splined balls is positioned to overlap with the torque transmission balls along the axial direction of the interconnecting shaft.

[0013] According to an embodiment of the present invention, a drive shaft configured to transmit rotary driving force includes: an interconnecting shaft; and a constant velocity joint connected to the interconnecting shaft. The constant velocity joint includes: an outer race forming a plurality of outer ball tracks; an inner race forming a plurality of inner ball tracks corresponding to the plurality of outer ball tracks; a ball retainer inserted between the outer and inner races and forming a plurality of windows; and a plurality of torque-transmitting balls, respectively disposed in the windows within the spaces formed by the pairs of outer and inner ball tracks. The outer and inner races are configured to achieve an angular hinge function allowing relative angular displacement between them, wherein the inner race is connected to the interconnecting shaft via a ball spline connection structure to achieve a length displacement function through relative axial displacement along the axial direction of the interconnecting shaft. The ball spline connection structure includes: an outer spline groove disposed on an inner race; an inner spline groove disposed on an interconnecting shaft corresponding to the outer spline groove; a sleeve member inserted between the inner race and the interconnecting shaft; and a plurality of splined balls disposed in a space formed by the pair of the outer and inner spline grooves, wherein the splined balls are received within sleeve windows formed on the sleeve member. The outer race includes an inner circumferential surface with a spherical surface shape having a first diameter, and the diagonal length of the inner race is less than the first diameter.

[0014] Splined balls can be arranged in a row, and when the joint is in a non-hinged state, the row of splined balls is positioned to overlap with the torque transmission balls along the axial direction of the interconnecting shaft.

[0015] The ball cage may include a first inclined surface disposed on an inner circumferential surface at one end thereof. The inner race may include a second inclined surface disposed on one end thereof. During the assembly of the torque-transmitting balls, the first and second inclined surfaces may be configured to contact each other when the ball cage and the inner race are at an angle relative to the outer race.

[0016] The outer race may include a coupling side and an opening side, and the outer race may also include a recessed space formed to accommodate at least a portion of the end of the interconnect shaft when the interconnect shaft is relatively displaced toward the coupling side.

[0017] The inner circumferential surface of the ball cage may include recessed openings. The distance between opposing recessed openings may be greater than the outer diameter of the inner race, and the width of the recessed openings may be greater than the width of the protrusions between the inner ball tracks of the inner race.

[0018] The diameter of the torque transmission ball (D) TB ) and the ball center diameter (BCD) of the torque transmission balls TB The ratio of (=D) TB / BCD TBThe value can range from 0.243 to 0.279. The diameter of the spline ball (D) SB ) and the center diameter of the splined ball (BCD) SB The ratio of DSB to BCD (= DSB / BCD) SB The range is from 0.116 to 0.185. The center diameter (BCD) of the spline ball is... SB ) and the ball center diameter (BCD) of the torque transmission balls TB The ratio of BCD SB / BCD TB It can be in the range of 0.464 to 0.507.

[0019] According to an embodiment of the present invention, a drive shaft configured to transmit rotational driving force includes: an interconnecting shaft; and a constant velocity joint connected to the interconnecting shaft. The constant velocity joint includes: an outer race forming a plurality of outer ball tracks; an inner race forming a plurality of inner ball tracks corresponding to the plurality of outer ball tracks; a ball retainer inserted between the outer race and the inner race and forming a plurality of windows; and a plurality of torque-transmitting balls, each disposed in a space formed by pairs of outer and inner ball tracks, respectively housed within a window. The inner race is connected to the interconnecting shaft via a ball spline connection structure to achieve length displacement functionality. The ball spline connection structure includes: an outer spline groove on the inner race; an inner spline groove on the interconnecting shaft corresponding to the outer spline groove; a sleeve member inserted between the inner race and the interconnecting shaft; and a plurality of splined balls disposed in a space formed by pairs of outer and inner spline grooves, wherein the splined balls are housed within sleeve windows formed on the sleeve member. The sleeve window is formed to extend longitudinally in a direction parallel to the axial direction of the interconnect shaft, and a plurality of spline balls are arranged adjacent to each other in contact, thereby forming a row within the sleeve window. The outer race includes a coupling side and an opening side. The outer race also includes a recessed space formed to receive at least a portion of the end of the interconnect shaft when the interconnect shaft is relatively displaced toward the coupling side.

[0020] According to the present invention, the inner race and the interconnecting shaft are connected by a ball spline connection structure to provide axial length displacement, which can reduce the diameter and weight of the interconnecting shaft. Furthermore, this allows for a simplified manufacturing process and reduced production costs.

[0021] Furthermore, various effects that can be obtained or anticipated due to the embodiments of the present invention are explicitly or implicitly disclosed in the detailed description of the embodiments of the present invention. Attached Figure Description

[0022] The accompanying drawings provided below are intended to aid in understanding the invention and, together with the detailed description, to provide embodiments of the invention. However, the technical features of the invention are not limited to the specific drawings, and the features disclosed in each drawing can be combined to form new embodiments. The embodiments described in this specification can be better understood by referring to the following description taken in conjunction with the accompanying drawings, wherein similar reference numerals indicate the same or functionally similar elements.

[0023] Figure 1 A drive shaft having a constant velocity joint according to an embodiment of the present invention is shown.

[0024] Figure 2 This is a perspective view of an equal velocity joint according to an embodiment of the present invention.

[0025] Figure 3 This is a front view of an equal velocity joint according to an embodiment of the present invention.

[0026] Figure 4 It is along Figure 3 The cross-sectional view taken from line AA.

[0027] Figure 5 It is along Figure 3 The cross-sectional view of line BB.

[0028] Figure 6 This is a partial cross-sectional view of an equal velocity joint according to an embodiment of the present invention.

[0029] Figure 7 This is a partial cross-sectional view showing the inner race in a constant velocity joint according to an embodiment of the present invention, which is in a hinged state relative to the outer race.

[0030] Figure 8 This is a cross-sectional view of the outer race of the constant velocity joint according to an embodiment of the present invention.

[0031] Figure 9 This is a cross-sectional view of the outer race of the constant velocity joint according to an embodiment of the present invention.

[0032] Figure 10 This is a side view of the inner seat ring according to an embodiment of the present invention.

[0033] Figure 11 It is along Figure 10 The cross-sectional view taken from line CC.

[0034] Figure 12 It is along Figure 10 The cross-sectional view of line DD.

[0035] Figure 13 This is a perspective view of the ball retainer of the constant velocity joint according to an embodiment of the present invention.

[0036] Figure 14 This is a cross-sectional view of the ball cage of the constant velocity joint according to an embodiment of the present invention.

[0037] Figure 15 This is a diagram showing an intermediate state during the process of inserting the inner race into the ball cage of the constant velocity joint according to an embodiment of the present invention.

[0038] Figure 16 This is a diagram showing the inner race inserted into the ball cage of the constant velocity joint according to an embodiment of the present invention.

[0039] Figure 17 This is a diagram illustrating the process of assembling torque transmission balls in a constant velocity joint according to an embodiment of the present invention, wherein the inner race and the ball cage are assembled within the outer race.

[0040] Figure 18 This is a perspective view of the sleeve of the constant velocity joint according to an embodiment of the present invention.

[0041] Figure 19 This is a perspective view showing a sleeve with balls assembled in a constant velocity joint according to an embodiment of the present invention.

[0042] Figure 20 This is a cross-sectional view showing the ball spline connection structure of the inner race of a constant velocity joint applied according to an embodiment of the present invention.

[0043] Figure 21 This shows that the connecting shaft has been removed from... Figure 6 The diagram shows the state of relative movement of the inner race in the direction of movement.

[0044] Figure 22 This shows that the connecting shaft has been removed from... Figure 6 The diagram shows the state of relative movement of the inner race in the moving direction.

[0045] Figure 23 This is a cross-sectional view showing a hinged state according to an embodiment of the invention, wherein the connecting shaft in the drive shaft moves to its maximum extent relative to the inner race in the insertion direction.

[0046] The accompanying drawings mentioned above are not necessarily drawn to scale and should be understood as simplified representations of various features illustrating the basic principles of the invention. For example, certain design features of the invention (including specific dimensions, orientations, positions, and shapes) will be determined in part by the specific intended application and environment of use. Detailed Implementation

[0047] The following detailed description of embodiments of the present invention is provided with reference to the accompanying drawings, enabling those skilled in the art to readily implement the invention. However, the invention can be implemented in various different forms and is not limited to the described embodiments.

[0048] The terminology used in this specification is intended for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular form is also intended to include the plural form unless the context clearly indicates otherwise. The terms “comprising” and / or “including” as used herein indicate the presence of stated features, elements, steps, operations, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, elements, steps, operations, components, and / or groups thereof. As used herein, the term “and / or” includes any and all combinations of one or more associated listed items. The term “connection” refers to the physical relationship between two components, indicating that the components are directly connected to each other or indirectly connected through one or more intermediate components.

[0049] When describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are used only to distinguish one component from another and do not limit the nature, order, or sequence of the components. When a component is described as "connected," "linked," or "attached" to another component, it may be directly connected, linked, or attached to that component, but it should also be understood that the other component may be "connected," "linked," or "attached" between them.

[0050] Figure 1 A drive shaft 10 with a constant velocity joint 13, according to an embodiment of the present invention, is shown. (Reference) Figure 1 The drive shaft 10 includes an interconnecting shaft 11 and a pair of constant velocity joints 13 and 14 respectively connected to both ends of the interconnecting shaft 11. The interconnecting shaft 11 can be formed as a solid shaft or a hollow shaft, depending on the requirements.

[0051] Constant velocity joints 13 and 14 can be fixed constant velocity joints without axial displacement function, or insertion-type constant velocity joints with axial displacement function. For example, constant velocity joints 13 and 14 can be fixed joints without axial displacement function or allowing limited axial displacement due to clearance, such as Rzeppa type constant velocity joints. One of constant velocity joints 13 and 14 can be used as an inner joint, and the other can be used as an outer joint. For example, in this embodiment of the invention, the constant velocity joint indicated by reference numeral 13 can be used as an inner joint, and the constant velocity joint indicated by reference numeral 14 can be used as an outer joint. Figure 1 In the middle, the constant velocity joint 13 is shown in a partial cross-sectional view.

[0052] Constant velocity joints 13 and 14 may be equipped with protective covers 15 and 16 for grease sealing, respectively. The two ends of the protective cover 15 may be secured to the constant velocity joint 13 and the interconnecting shaft 11 by means of fastening devices such as annular clamps. Similarly, the two ends of the protective cover 16 may be secured to the constant velocity joint 14 and the interconnecting shaft 11 by means of fastening devices such as annular clamps.

[0053] Figure 2 This is a perspective view of an equal velocity joint according to an embodiment of the present invention. Figure 3 This is a front view of the constant velocity connector according to the same embodiment. Figure 8 This is a cross-sectional view of the outer race of a constant velocity joint according to an embodiment of the present invention. (Reference) Figure 2 , Figure 3 and Figure 8 The constant velocity joint 13 includes an outer race 21, an inner race 22, a ball cage 23, and torque transmission balls 24. The outer race 21 may have a generally U-shaped configuration with an opening on one side and is designed to receive power from a power source.

[0054] The outer race 21 may have a closed connecting side and an open side formed on the opposite end of the connecting side, the connecting side being connected to a power source. Figure 8 In the middle, the right part corresponds to the connecting side, and the left part corresponds to the opening side. The inner race 22 and the ball cage 23 are inserted into the internal space of the outer race 21 through the opening side.

[0055] The inner race 22 is positioned within the internal space of the outer race 21. The inner race 22 is connected to the interconnecting shaft 11 in a manner that allows rotational power to be transmitted to the interconnecting shaft 11. The power transmission between the inner race 22 and the interconnecting shaft 11 is achieved through a ball spline connection structure 40, which will be described later.

[0056] like Figure 8 and Figure 9 As shown, the outer race 21 forms outer ball tracks 25 and 26 on its inner circumferential surface, and as... Figure 10 and Figure 11 As shown, the inner race 22 has inner ball tracks 27 and 28 formed on its outer circumferential surface. Outer ball tracks 25 and 26 and inner ball tracks 27 and 28 are formed at corresponding positions, and torque-transmitting balls 24 are positioned in the space formed by the corresponding pairs of outer ball tracks 25 and inner ball tracks 27, and outer ball tracks 26 and inner ball tracks 28. Rotational power can be transmitted between the outer race 21 and the inner race 22 via these torque-transmitting balls 24. For example, a constant velocity joint may include eight torque-transmitting balls 24, which are preferably arranged at equal intervals along the circumferential direction.

[0057] refer to Figure 8 and Figure 9The inner circumferential surface 51 of the outer ring 21 is formed with an inner diameter of D. O The spherical surface, the outer ball tracks 25 and 26 can be formed as recesses extending radially outward from the inner circumference towards the surface 51. Meanwhile, as... Figures 10 to 12 As shown, the inner race 22 forms a through hole 31 extending in the axial direction, and the outer circumferential surface 52 of the inner race 22 is formed with an outer diameter of D. I The spherical surface. The inner ball tracks 27 and 28 can be formed as recesses extending radially inward from the outer periphery toward the surface 52.

[0058] Figure 13 This is a perspective view of the ball cage of the constant velocity joint according to an embodiment of the present invention. Figure 14 This is a cross-sectional view of a ball cage. (Reference) Figure 3 , Figure 13 and Figure 14 The ball cage 23 can be inserted between the inner circumferential surface of the outer race 21 and the outer circumferential surface of the inner race 22, and it may include a plurality of windows 29 for receiving torque-transmitting balls 24. For example, the outer circumferential surface 53 and the inner circumferential surface 54 of the ball cage 23 may each be formed as a spherical surface.

[0059] Figure 4 It is along Figure 3 A cross-sectional view taken from line AA. Figure 5 It is along Figure 3 The cross-sectional view taken from line BB. (Reference) Figure 4 and Figure 5 The pair of outer ball tracks 25 and inner ball tracks 27 forms an opening angle α oriented towards the opening side, while the pair of outer ball tracks 26 and inner ball tracks 28 forms an opening angle β oriented towards the connecting side. The pairs of outer ball tracks 25 and inner ball tracks 27 with an opening angle α towards the opening side and the pairs of outer ball tracks 26 and inner ball tracks 28 with an opening angle β towards the connecting side can be arranged alternately in the circumferential direction. In this respect, the concept of opening angle is well known in the art to which this invention pertains and can refer to the angle formed between the center trajectory of a ball moving along the outer ball track and the center trajectory of a ball moving along the inner ball track. As described herein, a constant velocity joint having opening angles oriented in opposite directions in the non-hinged state is called a reverse ball track joint. This design minimizes the deviation of the ball cage 23 when torque is applied, allowing the ball cage 23 to self-center and reduce internal friction. This reduction in friction minimizes the loss of output torque relative to input torque in the constant velocity joint, which can contribute to improving the fuel efficiency or electrical efficiency of the vehicle.

[0060] According to an embodiment of the invention, the constant velocity joint 13 can be configured to allow relative angular displacement between the outer race 21 and the inner race 22, i.e., to perform an angular hinge function. For example, the outer race 21, the inner race 22, and the ball cage 23 can be configured as an Rzepa joint, which allows relative angular displacement between the outer race 21 and the inner race 22. Figure 6 The diagram shows either an aligned state or a non-hinged state in which the outer race 21 and the inner race 22 are aligned. In contrast, Figure 7 The hinged state of the inner race 22 relative to the outer race 21 is shown. Figure 7 The hinge angle A1 shown represents the angle formed between the axial direction X1 of the constant velocity joint 13 and the axial direction X of the drive shaft 10 (especially the interconnecting shaft 11).

[0061] According to an embodiment of the invention, the constant velocity joint 13 is configured such that the angular hinge function and the axial displacement function occur separately. As described above, the angular hinge function can be achieved by the shape of the inner circumferential surface of the outer race 21, the outer circumferential surface of the inner race 22, and the ball cage 23. On the other hand, the axial displacement function, which allows for length variation along the axial direction X of the drive shaft 10, is achieved by the ball spline connection structure between the inner race 22 and the interconnecting shaft 11.

[0062] In embodiments of the present invention, axial displacement is achieved through a ball spline connection structure between the inner race 22 and the interconnecting shaft 11. Therefore, it is not necessary to configure the interconnecting shaft as a tubular shaft as in conventional designs, and the outer diameter of the interconnecting shaft can be significantly reduced to near the outer diameter of a solid shaft without axial displacement. In this respect, the interconnecting shaft 11 can be used as a solid shaft. The reduction in the outer diameter of the interconnecting shaft enhances the design flexibility of the vehicle's interior space. Furthermore, achieving axial displacement through the ball spline connection structure between the inner race 22 and the interconnecting shaft 11 reduces the overall weight and significantly lowers manufacturing costs compared to conventional tubular shafts with axial displacement capabilities. Moreover, the application of the ball spline connection structure significantly reduces the axial force (GAF) generated in the vehicle, thereby providing superior NVH (noise, vibration, and harshness) performance compared to conventional constant velocity joints.

[0063] refer to Figure 13 and Figure 14 The ball cage 23 includes an opening 61 for assembling the inner race 22. (As shown) Figure 14 As shown, opening 61 extends from one side of window 29 to one end of ball retainer 23, and forms a recess at the edge region of the inner circumferential surface 54 of ball retainer 23. The opposing opening 61 forms an inlet diameter D. C The inlet diameter D C The outer diameter D is greater than the inner race 22. I(D) C >D I In addition, the width W of opening 61 C The width W is formed to be greater than the protrusion 56 on the inner seat ring 22. I ,like Figure 11 As shown (W) C >W I Due to this structure and size, such as Figure 15 and Figure 16 As shown, the inner race 22 can be assembled into the ball cage 23 through the opening 61.

[0064] Figure 17 This diagram illustrates the process of assembling torque-transmitting balls 24 in a constant velocity joint according to an embodiment of the present invention, wherein the inner race 22 and the ball cage 23 are already assembled within the outer race 21. To assemble the torque-transmitting balls 24 together with the inner race 22 and the ball cage 23 already in the outer race 21, the inner race 22 and the ball cage 23 must be tilted relative to the outer race 21 to a sufficient degree. To achieve this, the end of the inner race 22 needs to be fitted into the interior space of the outer race 21 in a hinged state. To achieve this, the diagonal length L of the inner race 22... I The inner diameter D of the inner circumferential surface 51 of the outer race 21 is designed to be smaller than that of the outer race 21. O (L) I <D O This configuration allows the inner race 22 to be fully hinged within the interior space of the outer race 21, enabling the torque transmission balls 24 to move along... Figure 17 The ball cage 23 can be easily assembled into the window 29 in the direction indicated by the arrow.

[0065] To allow the inner race 22 and the ball cage 23 to hinge at a large angle during the assembly of the torque transmission balls 24, an inclined surface 63 is formed on the inner circumferential surface 54 of the ball cage 23, and a corresponding inclined surface 64 is formed on the outer surface of the inner race 22. The inclined surface 63 of the ball cage 23 is inclined to widen radially outward from the spherical inner circumferential surface 54 of the ball cage 23, while the inclined surface 64 of the inner race 22 is inclined to widen radially inward. Figure 17 As shown within the dashed circle, the two inclined surfaces 63 and 64 are configured to contact each other when the inner race 22 and the ball cage 23 are hinged to their maximum angle. This configuration allows the inner race 22 and the ball cage 23 to hinge at a greater angle relative to the outer race 21. Therefore, during the assembly of the torque-transmitting balls 24, the window 29 of the ball cage 23 can be more exposed to the outside of the outer race 21, thus facilitating the assembly of the torque-transmitting balls 23.

[0066] The inner race 22 and the interconnecting shaft 11 are connected to each other via a ball spline connection structure 40, which transmits rotational power while allowing axial relative displacement. The ball spline connection structure 40 includes multiple external spline grooves 41, multiple internal spline grooves 42, a sleeve member 43, and multiple rows of splined balls 44. Here, when the joint is in a non-hinged state, the rows of splined balls 44 can be positioned to overlap with the torque-transmitting balls 24 along the axial direction of the constant velocity joint. Figure 11 As shown, an outer spline groove 41 is formed on the inner circumferential surface of the through-hole 31 defining the inner race 22, and an inner spline groove 42 is correspondingly formed on the outer circumferential surface of the interconnecting shaft 11. The outer spline groove 41 and the inner spline groove 42 form a pair to create space in which a row of splined balls 44 are inserted. The outer spline groove 41 and the inner spline groove 42 extend in a direction parallel to the axial direction X of the interconnecting shaft 11, and the splined balls 44 are designed to roll and / or slide within the space formed by the pair of outer spline grooves 41 and inner spline grooves 42. The rolling and / or sliding of the splined balls 44 contributes to the axial relative displacement between the inner race 22 and the interconnecting shaft 11, which in turn results in a change in the axial length of the drive shaft 10. The outer spline groove 41 and the inner spline groove 42 may have a cross-sectional shape such as an arch or a Gothic arch, allowing the splined balls 44 to contact the sides of the groove. This contact ensures that the inner race 22 and the interconnecting shaft 11 rotate together about the axial direction X.

[0067] Figure 18 This is a perspective view of the sleeve of the constant velocity joint according to an embodiment of the present invention. Figure 19 This is a perspective view showing a ball-bearing sleeve assembled in a constant velocity joint according to the same embodiment. (Reference) Figure 18 and Figure 19 The sleeve member 43 may have a hollow cylindrical shape with thin walls, allowing it to be inserted into the space between the outer circumferential surface of the interconnecting shaft 11 and the inner circumferential surface of the inner race 22. The sleeve member 43 is equipped with a plurality of sleeve windows 45, each accommodating a row of splined balls 44. The sleeve windows 45 may be arranged at equal intervals along the circumferential direction. Each sleeve window 45 extends in a direction parallel to the axial direction X of the interconnecting shaft 11. The radially outer portions of the splined balls 44 received in the sleeve windows 45 are received in the outer spline groove 41, while their radially inner portions are received in the inner spline groove 42.

[0068] refer to Figure 18 and Figure 19Multiple splined balls 44 arranged in a row are accommodated in each sleeve window 45, wherein adjacent splined balls 44 can contact each other. The sleeve window 45 can be formed as an elongated slot with a uniform width W. Because multiple splined balls 44 are arranged in a row within a single elongated sleeve window 45, the total length B of a row of splined balls is reduced. This reduction in length results in a shorter ball spline connection structure 40, thereby allowing for a more compact constant velocity joint. Figure 20 As shown, the reduced length B of the spline ball 44 minimizes the total length T of the inner race 22 while still satisfying the required axial displacements L1 and L2.

[0069] In this embodiment of the invention, since a plurality of splined balls 44 arranged in a row are housed together within a single elongated sleeve window 45, the splined balls 44 come into contact with each other as they slide and / or roll, resulting in reduced friction.

[0070] Figure 21 It shows that the interconnecting shaft has been removed from Figure 6 The state shown is relative to the state of the inner race moving in the outward direction. Figure 22 It shows that the interconnecting shaft has been removed from Figure 6 The state shown is the state of movement relative to the inner race in the insertion direction. Figure 6 In the ball spline connection structure 40, the center of a row of spline balls 44 is aligned with the center plane P of the joint. When the interconnecting shaft 11 moves from... Figure 6 The position of the middle part faces the opening side of the outer seat ring 21 (i.e., in the moving direction (in Figure 21 When it moves from center to left, it reaches Figure 21 The state shown. Conversely, when it is facing the connecting side of the outer seat ring 21 (i.e., in the insertion direction (in the direction shown)). Figure 22 When it moves from center to right, it reaches Figure 22 The state shown. Figure 21 This shows the state where the interconnecting axis has been moved to its maximum extent in the outward direction. Figure 22 This shows the state where the interconnect axis has been moved to its maximum extent in the insertion direction. Relative to... Figure 6 The position in the middle, the maximum movement distance L2 in the outward direction and the maximum movement distance L1 in the inward direction correspond to Figure 20 The corresponding displacement length is shown. Through this ball spline connection structure 40, a drive shaft with a limited total length displacement (=L1+L2) can be realized.

[0071] A specific structure was applied to limit the range of motion of the interconnecting shaft 11 during its movement out and in and to prevent displacement of the spline balls 44 and the sleeve member 43. (Reference) Figure 6 and Figure 21A first motion limiting part (i.e., a first retaining ring 47) and a second motion limiting part (i.e., a second retaining ring 48) are provided to limit the movement of the spline ball 44 during the removal of the interconnect shaft 11. The first retaining ring 47 is mounted on the inner circumferential surface at one end of the inner race 22 and is configured to support the outermost spline ball 44, thereby preventing the spline ball 44 from displacing from the inner race 22. On the other hand, the second retaining ring 48 is mounted on the outer circumferential surface at one end of the interconnect shaft 11 and is also configured to support the outermost spline ball 44, thereby preventing it from displacing from the interconnect shaft 11. When the interconnect shaft 11 moves to its maximum extent in the removal direction, as... Figure 21 As shown, the two ends of a row of splined balls 44 are supported by a first retaining ring 47 and a second retaining ring 48, respectively. This arrangement ensures that, on the one hand, the splined balls 44 and the sleeve member 43 are prevented from shifting from the inner race 22, and on the other hand, it restricts the outward movement of the interconnecting shaft 11.

[0072] refer to Figure 6 and Figure 22 A third motion limiting element, namely a third retaining ring 49, is provided to limit the movement of the splined balls 44 during the insertion of the interconnecting shaft 11. The third retaining ring 49 is mounted on the inner circumferential surface at opposite ends of the inner race 22 and is configured to support the outermost splined balls 44, thereby preventing the splined balls 44 from shifting from the inner race 22. When the interconnecting shaft 11 moves to its maximum extent in the insertion direction, as... Figure 22 As shown, one end of a row of splined balls 44 is supported by a third retaining ring 49. This arrangement ensures that the splined balls 44 and the sleeve member 43 are prevented from shifting from the inner race 22 during the insertion process.

[0073] like Figure 21 and Figure 22 As shown, the first retaining ring 47, the second retaining ring 48, and the third retaining ring 49 are configured to contact the splined ball 44 without contacting the sleeve member 43. This design prevents the sleeve member 43 from colliding with and being damaged by the retaining rings 47, 48, and 49. The aforementioned first retaining ring 47, second retaining ring 48, and third retaining ring 49 can be installed by insertion into a slot. In another embodiment, the retaining rings can be replaced by a riveted portion formed by a staking process.

[0074] Figure 23 This is a cross-sectional view showing the hinged state according to an embodiment of the invention, when the interconnecting shaft is moved to its maximum extent in the insertion direction relative to the inner race in the drive shaft. Figure 8 and Figure 23As shown, the outer race 21 includes a recessed space 67 to avoid interference with the interconnecting shaft 11 during hinged connection. The recessed space 67 is located between the ends of the outer ball grooves 25 and 26 and the connecting side of the outer race 21 to prevent interference with the ends of the interconnecting shaft 11 during its movement in the insertion direction during hinged connection. The recessed space 67 may have a generally annular shape and be radially outwardly recessed. Figure 23 As shown, due to the recessed space 67, interference between the end of the interconnecting shaft 11 and the outer race 21 can be avoided, thereby achieving a greater degree of hinge.

[0075] According to an embodiment of the present invention, in order to optimize the packaging, the diameter D of the torque transmission ball is adjusted. TB The diameter D of the spline ball SB The center diameter of the torque transmission ball bearings (BCD) TB The center diameter of the ball in the spline ball is BCD. SB The dimensions and ratios. Here, the ball center diameter BCD of the torque transmission balls. TB (BCD, Ball Center Diameter) refers to the diameter of the circle formed by the centers of multiple torque-transmitting balls 24 in a non-hinged state, such as... Figure 9 As shown. Similarly, the ball center diameter BCD of a spline ball is... SB This refers to the diameter of the circle formed by the centers of multiple splined balls 44. The diameter D of the torque transmission ball. TB The ball center diameter BCD of the torque transmission ball TB The ratio (=D) TB / BCD TB The value can range from 0.243 to 0.279. The diameter D of the spline ball... SB The center diameter of the ball in the spline ball is BCD SB The ratio (=D) SB / BCD SB The value can range from 0.116 to 0.185. Furthermore, the center diameter of the splined ball is BCD. SB The ball center diameter BCD of the torque transmission ball TB The ratio of BCD SB / BCD TB It can be in the range of 0.464 to 0.507.

[0076] These values ​​are derived from the allowable range of Hertzian contact stresses calculated theoretically for durability performance. Detailed specifications are shown in Table 1 below.

[0077] [Table 1]

[0078]

[0079] Embodiments of the present invention have been described above; however, the scope of the invention is not limited to these embodiments. The scope of the invention includes all modifications and variations that can be readily made by those skilled in the art and are considered equivalent to the embodiments of the invention.

Claims

1. A constant velocity joint configured to be coupled to an interconnecting shaft of a drive shaft, the constant velocity joint comprising: The outer race forms multiple outer ball tracks; The inner race forms multiple inner ball tracks corresponding to the multiple outer ball tracks; A ball retainer is inserted between the outer race and the inner race and forms a plurality of windows; as well as Multiple torque-transmitting balls are respectively arranged in the space formed by the pair of the outer ball track and the inner ball track, while being respectively housed in the window; The inner race is connected to the interconnecting shaft via a ball spline connection structure to achieve length displacement via relative axial displacement along the axial direction of the interconnecting shaft. The ball spline connection structure mentioned above includes: An external spline groove is provided on the inner race; An internal spline groove corresponding to the external spline groove is provided on the interconnecting shaft; A sleeve member inserted between the inner race and the interconnecting shaft; and A plurality of spline balls are disposed in the space formed by the pair of the outer spline groove and the inner spline groove, wherein the spline balls are accommodated within a sleeve window formed on the sleeve member. The outer race includes an inner circumferential surface with a spherical surface shape having a first diameter, and The diagonal length of the inner race is less than the first diameter.

2. The constant velocity joint according to claim 1, wherein the outer race includes a connecting side and an opening side. Furthermore, the outer race also includes a recessed space, which is formed to accommodate at least a portion of the end of the interconnecting shaft when the interconnecting shaft is displaced toward the connection side.

3. The constant velocity joint according to claim 1, wherein the splined balls are arranged in a row, and when the joint is in a non-hinged state, the row of splined balls is positioned to overlap with the torque transmission balls along the axial direction of the interconnecting shaft.

4. A drive shaft configured to transmit rotational driving force, the drive shaft comprising: Interconnecting shafts; as well as A constant velocity connector connected to the interconnecting shaft, The constant velocity joint includes: The outer race forms multiple outer ball tracks; The inner race forms multiple inner ball tracks corresponding to the multiple outer ball tracks; A ball cage, which is inserted between the outer race and the inner race and forms a plurality of windows; and Multiple torque-transmitting balls are respectively arranged in the space formed by the outer ball track and the inner ball track, each contained within the window. The outer race and the inner race are configured to enable an angular hinge function that allows for relative angular displacement between them. The inner race is connected to the interconnecting shaft via a ball spline connection structure to achieve length displacement via relative axial displacement along the axial direction of the interconnecting shaft. The ball spline connection structure mentioned above includes: An external spline groove is provided on the inner race; An internal spline groove corresponding to the external spline groove is provided on the interconnecting shaft; A sleeve member inserted between the inner race and the interconnecting shaft; and A plurality of spline balls are disposed in the space formed by the pair of the outer spline groove and the inner spline groove, wherein the spline balls are accommodated within a sleeve window formed on the sleeve member. The outer race includes an inner circumferential surface with a spherical surface shape having a first diameter, and The diagonal length of the inner race is less than the first diameter.

5. The drive shaft of claim 4, wherein the splined balls are arranged in a row, and when the joint is in a non-hinged state, the row of splined balls is positioned to overlap with the torque-transmitting balls along the axial direction of the interconnecting shaft.

6. The drive shaft of claim 4, wherein the ball cage includes a first inclined surface disposed on an inner circumferential surface at one end thereof. The inner race includes a second inclined surface disposed at one end thereof, and During the assembly of the torque transmission balls, when the ball cage and the inner race are at an angle relative to the outer race, the first inclined surface and the second inclined surface are configured to contact each other.

7. The drive shaft according to claim 4, wherein the outer race comprises a coupling side and an opening side, and The outer race further includes a recessed space formed to accommodate at least a portion of the end of the interconnect shaft when the interconnect shaft is displaced relative to the coupling side.

8. The drive shaft according to claim 4, wherein the inner circumferential surface of the ball cage includes a recessed opening. The distance between the opposing recessed openings is greater than the outer diameter of the inner ring, and The width of the recessed opening is greater than the width of the protrusion between the inner ball tracks of the inner race.

9. The drive shaft according to claim 4, wherein the diameter (D) of the torque transmission balls is... TB ) and the ball center diameter (BCD) of the torque transmission ball. TB The ratio of (=D) TB / BCD TB The value is in the range of 0.243 to 0.

279. The diameter (D) of the spline ball mentioned above SB ) and the ball center diameter (BCD) of the splined ball. SB The ratio of (=D) SB / BCD SB The value is in the range of 0.116 to 0.185, and The ball center diameter (BCD) of the spline ball is mentioned. SB ) and the ball center diameter (BCD) of the torque transmission ball. TB The ratio of BCD SB / BCD TB The value is in the range of 0.464 to 0.

507.

10. A drive shaft configured to transmit a rotational driving force, the drive shaft comprising: Interconnecting shafts; as well as A constant velocity connector connected to the interconnecting shaft, The constant velocity joint includes: The outer race forms multiple outer ball tracks; The inner race forms multiple inner ball tracks corresponding to the multiple outer ball tracks; A ball cage, which is inserted between the outer race and the inner race and forms a plurality of windows; and Multiple torque-transmitting balls are respectively arranged in the space formed by the pair of the outer ball track and the inner ball track, while being respectively housed in the window; The inner race is connected to the interconnecting shaft via a ball spline connection structure to achieve length displacement. The ball spline connection structure includes: An external spline groove is provided on the inner race; An internal spline groove corresponding to the external spline groove is provided on the interconnecting shaft; A sleeve member inserted between the inner race and the interconnecting shaft; and A plurality of spline balls are disposed in the space formed by the pair of the outer spline groove and the inner spline groove, wherein the spline balls are accommodated within a sleeve window formed on the sleeve member. The sleeve window is formed to extend longitudinally in a direction parallel to the axial direction of the interconnecting shaft, and The plurality of splined balls are arranged adjacent to each other in contact, thereby forming a row within the sleeve window. The outer race includes a connecting side and an opening side, and The outer race further includes a recessed space formed to accommodate at least a portion of the end of the interconnect shaft when the interconnect shaft is displaced relative to the coupling side.

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