JP2006162023A - Constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize dimensional setting corresponding to a miniaturization while maintaining various characteristics such as strength, durability and load capacity. <P>SOLUTION: In a constant velocity joint, the ratio (Dp/D) between the dimension (Dp) of an outer/inner PCD and the diameter (D) of an inner serration inner diameter 39 formed in the inner wall surface of the hole of an inner ring 34 is set within a range of 1.9≤(Dp/D)≤2.2. The ratio (Db/Dp) between the diameter (Db) of a ball 28 and the dimension (Dp) of the outer/inner PCD is set within a range of 0.2≤(Db/Dp)≤0.5. The ratio (Do/Dp) between the outer diameter (Do) of an outer cup 16 and the dimension (Dp) of the outer/inner PCD is set within a range of 1.4≤(Do/Dp)≤1.8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, a constant velocity joint that connects one transmission shaft and the other transmission shaft in a driving force transmission unit of an automobile.

  Conventionally, in a driving force transmission unit of an automobile, a constant velocity joint that connects one transmission shaft and the other transmission shaft and transmits a rotational force to each axle is used.

  As a constant velocity joint according to this type of prior art, for example, Non-Patent Document 1 discloses an outer race arranged on a joint shaft (driving shaft and driven shaft) with an offset by an equal distance on both sides of the joint center. A Rzeppa type constant velocity joint having a ball groove center and an inner race ball groove center is disclosed. In this Rzeppa type constant velocity joint, the six balls held by the cage are bisected between the constant velocity surface or the joint shaft by the relative movement of the ball groove of the outer race and the ball groove of the inner race. By being positioned on the surface, the driving contact is always maintained on the constant velocity surface, and constant velocity performance is ensured.

  By the way, in recent years, the need for weight reduction of a constant velocity joint has increased, and further downsizing of the constant velocity joint has been demanded. In this case, the strength, durability, load capacity, etc. of the constant velocity joint are set according to the basic dimensions of each element constituting the constant velocity joint, and various characteristics such as the strength, durability, load capacity, etc. of the constant velocity joint are set. It is required to set dimensions corresponding to miniaturization while maintaining each of them.

  In addition, as a technical idea related to the basic setting of this type of constant velocity joint, Patent Document 1 discloses a fixed type constant velocity universal joint including an outer joint member, an inner joint member, eight torque transmission balls, and a cage. Ratio Rw (= W / PCR) of the axial width (W) of the inner joint member and the length (PCR) of the line segment connecting the center of the guide groove of the inner joint member and the center of the torque transmitting ball Is set to 0.69 ≦ Rw ≦ 0.84.

Further, Patent Document 2, the outer race, inner race, in the fixed type constant velocity joint comprising six torque transmission balls and the cage, the diameter of the drive shaft is d, the torque transmitting balls diameter D _B and six set the pitch circle diameter of the torque transmitting balls when the D _P, which is the ratio of the diameter D _B of the torque transmission pawl to the diameter d of the drive shaft D _B / d to 0.65 to 0.72, the torque transmitting balls It is disclosed that D _P / D _B , which is a ratio of pitch circle diameter D _P to diameter D _B , is set to 3.4 to 3.8.

Charles E. Cooney, Jr., “UNIVERSAL JOINT AND DRIVESHAFT DESIGN MANUAL ADVANCES IN ENGINEERING SERIS NO.7” (USA), 2nd edition, THE SOCIETY OF AUTOMOTIVE ENGINEERS, INC. 1991 Year, p. 145-149 JP 2001-330051 A Japanese Patent Laid-Open No. 2003-97590

  However, the technical idea disclosed in Patent Document 1 has a problem that the number of parts increases and the manufacturing cost increases, and when actually implemented, it is difficult in terms of production technology.

  Further, in the technical idea disclosed in Patent Document 2, it is a dimension setting for improving the strength of a cage (cage) that holds a torque transmission ball, and does not contribute to downsizing of a constant velocity joint. There is no problem.

  The present invention has been made in consideration of the above problems, and a constant velocity joint capable of setting dimensions corresponding to miniaturization while maintaining various characteristics such as strength, durability, and load capacity. The purpose is to provide.

In order to achieve the above object, the present invention provides an outer body connected to one of two intersecting shafts, having a plurality of first guide grooves having an inner diameter surface and extending in the axial direction, and having one end opened. Members,
An inner ring connected to the other of the two shafts, extending in the axial direction and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the outer PCD and the inner PCD are the same. The ratio (Dp / D) between the dimension (Dp) and the diameter (D) of the inner diameter inner diameter portion formed on the inner wall surface of the hole of the inner ring is 1.9 ≦ (Dp / D) ≦ 2.2 It is set within the range of.

  According to the present invention, when the dimensional ratio (Dp / D) between the outer inner PCD (Dp) and the diameter (D) of the inner diameter portion of the inner serration is less than 1.9, the inner ring is thinned. However, if the dimensional ratio (Dp / D) exceeds 2.2, the constant velocity joint cannot be reduced in size.

  In the present invention, the ratio (Db / Dp) between the diameter (Db) of the ball and the dimension (Dp) of the outer inner PCD in which the outer PCD and the inner PCD are the same is 0.2 ≦ ( Db / Dp) is preferably set within the range of 0.5.

  In this case, if the dimensional ratio (Db / Dp) is less than 0.2, there is a problem that the ball diameter becomes too small and the durability is lowered, while the dimensional ratio (Db / Dp) is 0. If it exceeds 5, the ball becomes large, the thickness of the outer member becomes relatively thin, and the strength decreases.

  Further, according to the present invention, a ratio (Do / Dp) between an outer diameter (Do) of the outer member and a dimension (Dp) of the outer inner PCD in which the outer PCD and the inner PCD are the same is 1.4. It is preferable to set within the range of ≦ (Do / Dp) ≦ 1.8.

  In this case, if the dimensional ratio (Do / Dp) is less than 1.4, there is a problem that the thickness of the outer member is reduced and the strength is lowered, while the dimensional ratio (Do / Dp) is 1. If it exceeds 8, the outer diameter of the outer member will become large, and miniaturization cannot be achieved.

  Outer inner PCD dimension (Dp), inner diameter inner diameter portion (D) formed on the inner wall surface of the inner ring hole, ball diameter (Db), outer member outer diameter (Do) Etc. are set within a predetermined range, and dimensions corresponding to downsizing can be set while maintaining various characteristics such as strength, durability, and load capacity.

  Preferred embodiments of the constant velocity joint according to the present invention will be described below and described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 indicates a constant velocity joint according to an embodiment of the present invention. The constant velocity joint 10 is integrally connected to one end portion of the first shaft 12 and has an opening 14. It is basically composed of a cylindrical outer cup (outer member) 16 and an inner member 22 fixed to one end of the second shaft 18 and housed in the hole of the outer cup 16.

  As shown in FIGS. 1 and 3, the inner wall of the outer cup 16 has a spherical inner surface 24, and the inner surface 24 extends along the axial direction and around the axis. Six first guide grooves 26a to 26f are formed at intervals of 60 degrees.

  As shown in FIG. 2, the first guide groove 26 a (26 b to 26 f) formed in the outer cup 16 and having a longitudinal section along the axial direction having a curved shape has a point H as the center of curvature. In this case, the point H is formed along the axial direction of the outer cup 16 from the spherical center K of the inner diameter surface 24 (intersection where the imaginary plane (ball center plane) connecting the center point O of the ball 28 and the joint shaft 27 intersects). It is arranged at a position offset by a distance T1 on the opening 14 side.

  The inner member 22 includes an inner ring 34 in which a plurality of second guide grooves 32 a to 32 f corresponding to the first guide grooves 26 a to 26 f are formed along the circumferential direction of the outer diameter surface 35, and an inner wall surface of the outer cup 16. The first guide grooves 26a to 26f formed in the inner ring 34 and the second guide grooves 32a to 32f formed in the outer diameter surface 35 of the inner ring 34 are disposed so as to be able to roll, and perform a rotational torque transmission function. Six balls 28 and six holding windows 36 for holding the balls 28 are formed along the circumferential direction, and have a retainer 38 interposed between the outer cup 16 and the inner ring 34.

  The inner ring 34 has an inner serration inner diameter portion 39 that is serrated and fitted to the serration portion formed at the end of the second shaft 18 on the inner wall surface of the hole portion, and is further attached to the annular groove of the second shaft 18. It is integrally fixed to the end of the second shaft 18 via a ring-shaped locking member 40. A plurality of second guide grooves 32 a to 32 f are formed on the outer diameter surface 35 of the inner ring 34 so as to correspond to the first guide grooves 26 a to 26 f of the outer cup 16 and are spaced apart at equal angles along the circumferential direction. The

  As shown in FIG. 2, the second guide grooves 32 a to 32 f formed in the inner ring 34 and having a longitudinal section along the axial direction formed in a curved shape have a point R as the center of curvature. In this case, the point R is a distance T2 along the axial direction from the spherical center K of the inner diameter surface 24 (intersection where the imaginary plane (ball center plane) connecting the center point O of the ball 28 and the joint shaft 27 is orthogonal). Arranged at the offset position.

  A point H that is the center of curvature of the first guide grooves 26a to 26f of the outer cup 16 and a point R that is the center of curvature of the second guide grooves 32a to 32f of the inner ring 34 are the spherical center K of the inner diameter surface 24 (ball center plane). And the joint shaft 27), which are respectively opposite to each other and offset at equal distances (T1 = T2) along the axial direction. The point H is located on the opening 14 side of the outer cup 16 with respect to the spherical surface center K of the inner diameter surface 24, and the point R is located on the back part 46 side of the outer cup 16. The radius of curvature of R is set so as to cross like a cross (see FIG. 2).

  The balls 28 are formed of, for example, steel balls and roll one by one along the circumferential direction between the first guide grooves 26 a to 26 f of the outer cup 16 and the second guide grooves 32 a to 32 f of the inner ring 34. Six are possible. The ball 28 transmits the rotational torque of the second shaft 18 to the first shaft 12 via the inner ring 34 and the outer cup 16, and along the first guide grooves 26a to 26f and the second guide grooves 32a to 32f. By rolling, relative displacement in the intersecting angular direction between the second shaft 18 (inner ring 30) and the first shaft 12 (outer cup 16) is enabled. The rotational torque is suitably transmitted from either direction between the first shaft 12 and the second shaft 18.

  As shown in FIGS. 4A and 4B, the pitch diameter of the first guide grooves 26a to 26f when the six balls 28 are in point contact with the first guide grooves 26a to 26f of the outer cup 16 is defined as an outer PCD. In this embodiment, when the pitch diameter of the second guide grooves 32a to 32f in the state where the six balls 28 are in point contact with the second guide grooves 32a to 32f of the inner ring 34 is the inner PCD, It is assumed that the outer PCD and the inner PCD are equal (outer PCD = inner PCD), and the difference between the outer PCD and the inner PCD is set to zero. Therefore, in the following description, both the outer PCD and the inner PCD are collectively referred to as an outer inner PCD.

  The constant velocity joint 10 according to the present embodiment is basically configured as described above. Next, the operation, action, and effect will be described.

  When the second shaft 18 rotates, the rotational torque is transmitted from the inner ring 34 to the outer cup 16 via each ball 28, and the first shaft 12 rotates in a predetermined direction while maintaining constant velocity with the second shaft 18. To do.

  At that time, when the crossing angle (operating angle) between the first shaft 12 and the second shaft 18 changes, the ball rolls between the first guide grooves 26a to 26f and the second guide grooves 32a to 32f. Under the action of 28, the retainer 38 tilts by a predetermined angle to allow the angular displacement.

  In this case, since the six balls 28 held by the holding window 36 of the retainer 38 are located on the uniform velocity surface or the bisected angle surface between the first shaft 2 and the second shaft 12, 18, the driving contact is made. The constant velocity is always maintained on the constant velocity surface. As described above, the angular displacement of the first shaft 12 and the second shaft 18 is preferably allowed while maintaining the constant velocity.

  Next, the setting of various dimensions for achieving downsizing of the constant velocity joint 10 will be described in detail below.

  A diameter (D) of the inner diameter inner diameter portion 39 is arbitrarily set, and a dimension of the outer inner PCD that is the minimum thickness of the inner ring 34 is set based on the diameter (D) of the inner diameter inner diameter portion 39. The diameter (D) of the inner diameter inner diameter portion 39 passes through the center of the hole of the inner ring 34, and the bottom of the valley portion of one inner diameter inner diameter portion 39 and the valley portion of the other inner diameter inner diameter portion 39. This means the dimension (maximum diameter) between the bottom and the bottom (see FIG. 5). A predetermined bond strength is ensured by the minimum thickness of the inner ring 34. As shown in FIG. 6, the value of the outer inner PCD is obtained from a characteristic straight line L related to the relationship between the diameter of the inner inner diameter portion 39 and the outer inner PCD.

  In this case, when the diameter of the inner serration inner diameter portion 39 is D and the outer inner PCD is Dp, the dimensional ratio (Dp / D) between the outer inner PCD (Dp) and the diameter (D) of the inner serration inner diameter portion 39. ) Is preferably set within a range of 1.9 ≦ (Dp / D) ≦ 2.2.

  If the dimensional ratio (Dp / D) is less than 1.9, there is a problem that the inner ring 34 becomes too thin and the strength is lowered. On the other hand, the dimensional ratio (Dp / D) is 2.2. This is because the constant velocity joint 10 cannot be reduced in size.

  Further, as shown in FIG. 7, the outer diameter of the outer cup 16 is set based on a characteristic line M related to the relationship between the outer diameter of the cup portion of the outer cup 16 and the outer inner PCD. In this case, when the outer diameter of the outer cup 16 is Do, the dimensional ratio (Do / Dp) between the outer diameter (Do) of the outer cup 16 and the outer inner PCD (Dp) is 1.4 ≦ (Do / Dp). It is preferable to set within the range of ≦ 1.8.

  If the dimensional ratio (Do / Dp) is less than 1.4, there is a problem that the thickness of the outer cup 16 is reduced and the strength is lowered, while the dimensional ratio (Do / Dp) exceeds 1.8. This is because the outer diameter of the outer cup 16 becomes large and the miniaturization cannot be achieved.

  Further, as shown in FIG. 8, the ring width of the inner ring 34 is based on a characteristic straight line N relating to the relationship between the ring width of the inner ring 34 along the axial direction of the second shaft 18 and the outer inner PCD. Set. In this case, when the ring width of the inner ring 34 is W, the dimensional ratio (W / Dp) between the ring width (W) of the inner ring 34 and the outer inner PCD (Dp) is 0.38 ≦ (W / Dp ) ≦ 0.42 is preferable.

  Furthermore, as shown in FIG. 9, the diameter of the ball 28 is set based on a characteristic straight line Q relating to the relationship between the diameter of the ball 28 and the outer inner PCD. In this case, when the diameter of the ball 28 is Db, the dimensional ratio (Db / Dp) between the diameter (Db) of the ball 28 and the outer inner PCD (Dp) is 0.2 ≦ (Db / Dp) ≦ 0.5. It is preferable to set within the range.

  If the dimensional ratio (Db / Dp) is less than 0.2, there is a problem that the diameter of the ball 28 becomes too small and the durability is lowered, while the dimensional ratio (Db / Dp) is 0.5. If it exceeds, the ball 28 becomes large, the thickness of the outer cup 16 becomes relatively thin, and the strength is lowered. The inner sphere diameter and outer sphere diameter of the retainer 38 that holds the ball 28 are arbitrarily set according to the layout.

  Thus, by setting each dimension, it is possible to set the dimension of the constant velocity joint 10 corresponding to downsizing while maintaining various characteristics such as strength, durability, and load capacity.

It is a longitudinal cross-sectional view along the axial direction of the constant velocity joint which concerns on embodiment of this invention. FIG. 2 is a partially enlarged longitudinal sectional view of the constant velocity joint shown in FIG. 1. It is a partial cross section side view seen from the axial direction (arrow X direction) of the constant velocity joint shown in FIG. FIG. 4A is a longitudinal sectional view showing the outer PCD which is the pitch circle diameter of the first guide groove formed in the outer cup, and FIG. 4B is a diagram showing the inner PCD which is the pitch circle diameter of the second guide groove formed in the inner ring. It is a longitudinal cross-sectional view shown. It is a partial expanded sectional view of the constant velocity joint which shows a shaft serration part diameter (D), outer inner PCD (Dp), outer cup outer diameter (Do), ball diameter (Db), etc. It is a characteristic view which shows the characteristic straight line L concerning the relationship between the diameter of an inner serration inner diameter part, and outer inner PCD. It is a characteristic view which shows the characteristic straight line M which concerns on the relationship between the outer inner PCD and the outer diameter of an outer cup. It is a characteristic view which shows the characteristic straight line N concerning the relationship between the outer inner PCD and the inner width of the inner ring. It is a characteristic view which shows the characteristic straight line Q which concerns on the relationship between outer inner PCD and a ball diameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Constant velocity joint 12 ... 1st axis | shaft 16 ... Outer cup 18 ... 2nd axis | shaft 24 ... Inner diameter surface 26a-26f ... 1st guide groove 28 ... Ball 32a-32f ... 2nd guide groove 34 ... Inner ring 35 ... Outer diameter surface 36 ... Holding window 38 ... Retainer 39 ... Inner serration inner diameter part

Claims (4)

An outer member connected to one of two intersecting shafts, having an inner diameter surface and extending in the axial direction, and having a plurality of first guide grooves open at one end;
An inner ring connected to the other of the two shafts, extending in the axial direction and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the outer PCD and the inner PCD are the same. The ratio (Dp / D) between the dimension (Dp) and the diameter (D) of the inner diameter inner diameter portion formed on the inner wall surface of the hole of the inner ring is 1.9 ≦ (Dp / D) ≦ 2.2 A constant velocity joint that is set within the range of An outer member connected to one of two intersecting shafts, having an inner diameter surface and extending in the axial direction, and having a plurality of first guide grooves open at one end;
An inner ring connected to the other of the two shafts, extending in the axial direction and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the ball diameter (Db), the outer PCD, and the inner PCD The constant velocity joint is characterized in that the ratio (Db / Dp) to the dimension (Dp) of the outer inner PCD having the same value is set within a range of 0.2 ≦ (Db / Dp) ≦ 0.5 . An outer member connected to one of two intersecting shafts, having an inner diameter surface and extending in the axial direction, and having a plurality of first guide grooves open at one end;
An inner ring connected to the other of the two shafts, extending in the axial direction and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the outer diameter (Do) of the outer member, the outer PCD and the inner PCD The ratio (Do / Dp) to the dimension (Dp) of the outer inner PCD having the same PCD is set within a range of 1.4 ≦ (Do / Dp) ≦ 1.8, etc. Fast joint. An outer member connected to one of two intersecting shafts, having an inner diameter surface and extending in the axial direction, and having a plurality of first guide grooves open at one end;
An inner ring connected to the other of the two shafts, extending in the axial direction and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the outer PCD and the inner PCD are the same. The ratio (Dp / D) between the dimension (Dp) and the diameter (D) of the inner diameter inner diameter portion formed on the inner wall surface of the hole of the inner ring is 1.9 ≦ (Dp / D) ≦ 2.2 Is set within the range of
The ratio (Db / Dp) between the diameter (Db) of the ball and the dimension (Dp) of the outer inner PCD is set within a range of 0.2 ≦ (Db / Dp) ≦ 0.5,
The ratio (Do / Dp) between the outer diameter (Do) of the outer member and the dimension (Dp) of the outer inner PCD is set within a range of 1.4 ≦ (Do / Dp) ≦ 1.8. Constant velocity joints characterized in that

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