JP2006017136A - Constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant velocity joint capable of easily and precisely machining an inner member and facilitating an assembling operation and reducing manufacturing costs by improving productivity. <P>SOLUTION: A ring-shaped member 50 is mounted on a columnar portion 45 of a trunnion 44, and a roller member 48 retaining a needle bearing 46 on its inner periphery is mounted on the columnar portion 45. The needle bearing 46 is retained between a flange 60 formed on an end of the roller member 48 and the ring-shaped member 50 mounted on the trunnion 44 in a state having a designated gap. <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.

  FIG. 11 shows a partial cross section of the constant velocity joint 2 according to the prior art (see Patent Document 1). The constant velocity joint 2 includes a cylindrical outer member 4 connected to one transmission shaft, and an inner member 6 inserted into the outer member 4 and connected to the other transmission shaft. Three guide grooves 8 extending along the axial direction are formed on the inner peripheral surface of the outer member 4. On the other hand, the inner member 6 has three trunnions 10 that bulge toward the respective guide grooves 8, and a roller member 14 is attached to each trunnion 10 via a plurality of needle bearings 12. The roller member 14 is rotatably engaged with the guide groove 8 of the outer member 4.

  In this prior art, in order to hold the needle bearing 12 against the roller member 14 so as not to drop off, a groove portion 16 is formed around the inner peripheral portion of the roller member 14, and the needle bearing 12 is press-fitted into the groove portion 16. Yes.

  When mounting the needle bearing 12 in the groove 16, for example, the needle bearing 12 is arranged in the groove 16 with one needle bearing 12 left, and then the remaining one is press-fitted using the Keystone effect. In this case, in order to hold the plurality of needle bearings 12 in a suitable state in the groove portion 16, the needle bearing 12 and the groove portion 16 are extremely high so that the tolerance between the groove portion 16 and the needle bearing 12 is as small as possible. It is necessary to process to accuracy.

  Moreover, when forming the groove part 16 in the inner peripheral part of the roller member 14, since there are flange parts 17a and 17b on both sides of the groove part 16, the machining tool is inserted into the groove part 16 to perform cutting, and is generated by machining. In order to reliably discharge the cutting waste to the outside, extremely difficult work is forced.

  In Patent Document 1, instead of forming the groove portion 16 in the inner peripheral portion of the roller member 14, a round hole without the flange portions 17a and 17b is formed, and then two washers are engaged with the inner peripheral portion. A technique for replacing the flange portions 17a and 17b is also disclosed. In this case, processing of the round hole itself is easy, but the washer must be engaged with the inner peripheral portion of the roller member 14, and processing of the engagement groove for that purpose is required. Further, it is necessary to engage the washer with the engaging groove.

  In order to solve these problems, the present applicant has proposed a constant velocity joint 18 having a structure shown in FIG. 12 (see Patent Document 2). In the constant velocity joint 18, the enlarged diameter portion 22 is formed at the proximal end portion of the trunnion 10 formed in the inner member 6, while the inner peripheral portion of the roller member 14 is on the end side in the bulging direction of the trunnion 10. Only the flange portion 17a is formed.

  In this case, the processing of the inner peripheral portion of the roller member 14 and the cutting waste discharging processing during processing become extremely easy. Further, the needle bearing 12 mounted between the trunnion 10 and the roller member 14 is held between the flange portion 17a of the roller member 14 and a step portion 24 formed in the enlarged diameter portion 22 of the inner member 6. .

Japanese Patent Laid-Open No. 10-184717 JP-A-11-210776

  Incidentally, in the constant velocity joint 18 shown in FIG. 12, it is necessary to provide the enlarged diameter portion 22 at the proximal end portion of the trunnion 10. The enlarged diameter portion 22 is required to have high dimensional accuracy because it is necessary to appropriately regulate the amount of movement of the needle bearing 12 along the trunnion 10. In addition, the processed shape of the enlarged diameter portion 22 is greatly restricted so that stress does not concentrate between the cylindrical portion of the trunnion 10 and the stepped portion 24 of the enlarged diameter portion 22.

  The present invention has been made in view of the above-described problems, and can easily and accurately process the inner member, facilitate assembly work, improve productivity, and reduce manufacturing costs. It is an object of the present invention to provide a constant velocity joint that can be used.

In order to achieve the above object, the present invention provides a cylindrical outer member that is provided with a plurality of guide grooves that are spaced apart from each other and extend along the axial direction, and that is provided on an inner peripheral surface and connected to one transmission shaft. In the constant velocity joint having an inner member that is inserted into the inner space where the outer member opens and is connected to the other transmission shaft,
The inner member is
A plurality of trunnions bulging toward the guide groove;
A ring-shaped roller member that contacts the guide groove and is externally fitted to the trunnion;
A plurality of rolling elements interposed between the trunnion and the roller member so as to freely roll;
With
On the inner peripheral part of the roller member, a flange part is formed which is formed on the end side in the bulging direction of the trunnion and projects radially inward, and circulates along the inner peripheral part.
An annular member is attached to the base end side of the trunnion,
The rolling element is held between the flange portion and the annular member.

  In this case, since the flange portion is formed only on the end portion side of the trunnion in the bulging direction of the roller member, a processing tool is inserted from the direction in which the flange portion of the roller member is not formed. Can be processed easily and with high accuracy. Moreover, a rolling element can be inserted and attached to the processed roller member from the end side where the flange portion is not formed.

  Note that when the rolling elements are mounted on the inner peripheral portion of the roller member, it is not necessary to perform press-fitting processing using the keystone effect, so that high manufacturing accuracy is not required for the rolling elements, and therefore the diameter of the rolling elements is reduced. Thus, the diameter of the trunnion can be enlarged and / or the roller member can be thickened to improve the strength or downsize the constant velocity joint.

  When the roller member is assembled to the trunnion, the annular member is attached to the trunnion, and then the roller member having a plurality of rolling elements attached to the inner peripheral portion is inserted into the trunnion. In this case, the rolling element is held between the flange portion of the roller member and the annular member. In addition, workability | operativity at the time of attaching a roller member to a trunnion can be improved by hold | maintaining a rolling element to the inner peripheral part of a roller member beforehand using grease or wax.

  Since the annular member holding the rolling element is configured separately from the trunnion, the degree of freedom of the trunnion processing shape is improved. Further, by selecting the thickness of the annular member, the amount of movement of the rolling element relative to the trunnion can be adjusted easily and with high accuracy.

  The annular member can be attached to the trunnion in a stable state by chamfering the portion that contacts the proximal end portion of the trunnion, thereby improving the durability of the annular member and the trunnion.

  Further, by setting the ratio of the radius of curvature of the outer peripheral surface from the cylindrical portion of the trunnion to which the roller member is fitted to the base end portion to the diameter of the cylindrical portion, in a range of 0.05 or more and 0.35 or less. In a state where a good layout is ensured, the stress concentrated on the base end portion can be reduced and the durability of the trunnion can be improved.

  According to the present invention, the inner peripheral portion of the roller member to which the rolling element is mounted can be processed extremely easily and with high accuracy. In addition, an inner member having a sufficient strength and a high degree of freedom in designing the shape of the base end portion of the trunnion can be easily manufactured. Further, the inner member can be assembled simply by inserting the roller member into the trunnion on which the annular member is mounted after the rolling element is mounted on the inner peripheral portion of the roller member. Therefore, the productivity of the constant velocity joint can be improved and the manufacturing cost can be reduced.

  A preferred embodiment of the constant velocity joint according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of a main part of a constant velocity joint 30 according to the present embodiment. The constant velocity joint 30 is integrally connected to one end portion of one transmission shaft (not shown) and has a cylindrical outer member 32 having an opening, and is connected to one end portion of the other transmission shaft 33 and is connected to one end portion of the outer member 32. It is basically composed of an inner member 34 inserted into the inner space.

  In the inner space of the outer member 32, three guide grooves 36 are formed extending in the axial direction and spaced by 120 degrees around the axis. The guide groove 36 includes a ceiling portion 38 formed in a curved shape having a gentle cross section, and sliding portions 40a and 40b formed in a circular arc shape facing each other on both sides of the ceiling portion 38.

  A ring-shaped spider 42 constituting the inner member 34 is fitted on the transmission shaft 33. Three trunnions 44 bulging toward the guide groove 36 are integrally formed on the outer peripheral surface of the spider 42. The cylindrical portion 45 of the trunnion 44 and the outer peripheral surface of the spider 42 are smoothly connected by the base end portion 47.

  As shown in the cross-sectional view of FIG. 2, an annular member 50 having an outer diameter d2 is attached to the cylindrical portion 45 of the trunnion 44. The inner diameter d1 is set slightly larger than the diameter D of the cylindrical portion 45. Instead of the annular member 50, as shown in FIG. 3, an annular member 54 in which a chamfered portion 52 is formed at a portion that contacts the base end portion 47 of the trunnion 44 may be attached. When the annular member 54 is attached, the chamfered portion 52 abuts on the base end portion 47 of the trunnion 44, so that the annular member 54 is held in the trunnion 44 in a stable state.

  A ring-shaped roller member 48 is fitted onto the cylindrical portion 45 of the trunnion 44 via a plurality of needle bearings (rolling elements) 46. As shown in FIG. 4, the needle bearing 46 is held between the outer peripheral portion of the cylindrical portion 45 and the inner peripheral portion of the roller member 48 via grease or wax.

  As shown in FIG. 1, the outer peripheral surface of the roller member 48 has an arcuate surface portion 56 formed corresponding to the cross-sectional shape of the sliding portions 40 a and 40 b, and a ceiling portion 38 of the guide groove 36 from the arcuate surface portion 56. A first annular inclined surface portion 58a continuous to the side, and a second annular inclined surface portion 58b continuous from the arcuate surface portion 56 to the spider 42 side.

  On the inner peripheral portion of the roller member 48, a flange portion 60 is provided on the end surface of the guide groove 36 on the ceiling portion 38 side so as to protrude radially inward. A flange portion is not provided on the end surface of the inner peripheral portion of the roller member 48 on the spider 42 side. Therefore, the inner peripheral portion of the roller member 48 can be processed easily and with high accuracy by inserting a processing tool. In addition, it is very easy to discharge cutting waste generated during processing.

  The inner diameter of the roller member 48 is set slightly larger than the outer diameter d2 of the annular member 50 or the annular member 54 attached to the trunnion 44. Of the inner peripheral portion of the roller member 48, the proximal end portion of the flange portion 60 can be formed with a circumferential groove 62 for reducing the sliding resistance against the needle bearing 46 and releasing grease or wax. .

  As shown in FIG. 5, the gap from the flange portion 60 of the roller member 48 to one end face of the needle bearing 46 is A, and the gap from the other end face of the needle bearing 46 to the annular member 50 or the annular member 54 is B. The gap between the end surface of the roller member 48 on the spider 42 side and the spider 42 is Y, and the gap is set so that the smaller one of the gaps X = A + B, Y is within the regulation range of the movement amount of the roller member 48 relative to the trunnion 44. X and Y are set.

  The constant velocity joint 30 of the present embodiment is basically configured as described above. Next, an assembling method and operational effects thereof will be described.

  When the constant velocity joint 30 is assembled, the annular member 50 is attached to each cylindrical portion 45 of the trunnion 44. The annular member 50 has an inner diameter d1 that is set slightly larger than the diameter D of the cylindrical portion 45, and is held by the base end portion 47 of the cylindrical portion 45 as shown in FIG.

  On the other hand, a plurality of needle bearings 46 are attached to the inner peripheral portion of the roller member 48 via grease or wax. In this case, since the flange portion 60 is formed only on one side on the inner peripheral portion of the roller member 48, it is extremely easy to insert the needle bearing 46 from the end surface of the roller member 48 toward the flange portion 60 side. The roller member 48 can be mounted.

  Next, the roller member 48 to which the needle bearing 46 is attached is attached to each cylindrical portion 45 of the trunnion 44, and the inner member 34 is completed. In this case, the needle bearing 46 is held between the flange portion 60 of the roller member 48 and the annular member 50 attached to the cylindrical portion 45 of the trunnion 44.

  The inner member 34 configured as described above is inserted into the inner space of the outer member 32, and each roller member 48 is engaged with the guide groove 36, thereby completing the assembly of the constant velocity joint 30 shown in FIG. To do.

  Here, as shown in FIG. 5, a predetermined gap A is provided between one end surface of the needle bearing 46 and the flange portion 60 of the roller member 48 and between the other end surface of the needle bearing 46 and the annular member 50. And B (gap X = A + B) are secured, and a predetermined gap Y is secured between the end surface of the roller member 48 on the side where the flange portion 60 is not formed and the spider 42 of the inner member 34. Yes. Therefore, when the transmission shaft 33 of the inner member 34 rotates while maintaining a predetermined angle with respect to the transmission shaft (not shown) of the outer member 32, the movement amount of the roller member 48 is restricted by the smaller gap X or Y. In this state, it is displaced in the direction along the axis of the trunnion 44.

  Further, since the annular member 50 is configured separately from the trunnion 44, for example, by selecting the thickness of the annular member 50, the gap X that regulates the amount of movement of the roller member 48 can be arbitrarily adjusted. it can. Further, since the annular member 50 can be configured so that the end face side surface of the needle bearing 46 is a flat surface, the radius of curvature r1 of the base end portion 47 of the trunnion 44 is set to a desired radius to ensure the strength of the trunnion 44. On the other hand, the gap B with the needle bearing 46 can be set with high accuracy.

  Instead of the annular member 50, as shown in FIG. 6, by attaching an annular member 54 having a chamfered portion 52 to the proximal end portion 47 of the trunnion 44, the annular member 54 is formed on the curved surface of the proximal end portion 47. The annular member 54 can be stably held by abutting the chamfered portion 52.

  Further, as shown in FIG. 7, an annular member 64 having an outer diameter d2 larger than the diameter of the inner peripheral portion of the roller member 48 is attached to the trunnion 44, whereby a gap between the end surface of the roller member 48 and the annular member 64 is obtained. The amount of movement of the roller member 48 can also be regulated by Z.

  Similarly, as shown in FIG. 8, an annular member 66 having an outer diameter d2 larger than the diameter of the inner peripheral portion of the roller member 48 and having a chamfered portion 65 formed on the base end portion 47 side is used as the trunnion 44. The movement amount of the roller member 48 can be regulated by the gap Z between the end surface of the roller member 48 and the annular member 66.

  In each of the embodiments described above, the gap between the needle bearing 46 and the annular members 50 and 54 or the gap between the roller member 48 and the annular members 64 and 66 is set as follows. Can do.

  FIG. 9 is a schematic side view of the state where the inner member 34 is inclined by an inclination angle θ around one axis of the trunnion 44, and FIG. 10 is a schematic front view of this state.

If the radius of rotation of the center of the roller member 48 relative to the central axis of the outer member 32 is R, the outer member 32 is guided from a plane including the axis of the trunnion 44 that is the rotational center of the inclination angle θ and the central axis of the outer member 32. The distance a to the center of each roller member 48 moved along the groove 36 is
a = R · cos 30 °. The distance c from the axis of the trunnion 44 that is the center of rotation to the center of the roller member 48 that has moved along the guide groove 36 of the outer member 32 is expressed as follows:
c = a / cosθ
It becomes. In this case, the roller member 48 moved along the guide groove 36 is directed toward the outer direction of the trunnion 44.
b = c−a
It moves by the movement amount b. Therefore, the roller member 48 attached to the trunnion 44 that is the rotation center of the inclination angle θ is in the inner direction of the trunnion 44.
δ = b · tan 30 ° = R / 2 · (1 / cos θ−1)
It moves by the movement amount δ.

From this result, the gap K between the needle bearing 46 and the annular members 50 and 54, or the gap K between the roller member 48 and the annular members 64 and 66, and the maximum inclination angle of the inner member 34 as θmax,
K> δ = R / 2 · (1 / cos θmax−1)
In order to secure the desired inclination angle θ and to optimize the length of the trunnion 44 and to set the inner member 34 to the minimum necessary size, a constant velocity joint can be obtained. 30 can be made small.

The amount of movement of the trunnion 44 of the roller member 48 in the outward direction is such that the positions of the two roller members 48 are fixed and the remaining one roller member 48 is moved along the guide groove 36 of the outer member 32. The amount of movement of one roller member 48 can be obtained. This amount of movement ε is
ε = 3R / 2 · (1 / cosθ-1)
It becomes. Therefore, in order to stably hold the roller member 48 on the trunnion 44, the distance M from the end of the needle bearing 46 to the end of the trunnion 44 in the bulging direction is
M> ε = 3R / 2 · (1 / cos θmax−1)
It is preferable to design so as to satisfy this relationship.

  Further, the ratio r1 / D between the radius of curvature r1 (see FIG. 5) of the curved surface from the cylindrical portion 45 to the base end portion 47 and the diameter D of the cylindrical portion 45 is adjusted, and the layout of the inner member 34 and the roller member 48 Table 1 shows the results of testing the strength of the trunnion 44 based on the relationship. In this case, the strength of the trunnion 44 can be ensured by setting 0.05 ≦ r1 / D, preferably 0.08 ≦ r1 / D. On the other hand, when 0.35 <r1 / D is set, the inner member 34 is increased in thickness, which causes a problem in terms of layout. Therefore, by setting 0.05 ≦ r1 / D ≦ 0.35, preferably 0.08 ≦ r1 / D ≦ 0.25, it is possible to secure a good layout and The stress concentration can be reduced and the strength of the trunnion 44 can be sufficiently secured.

It is principal part sectional drawing of the constant velocity joint which concerns on this embodiment. It is a partial cross section perspective view of the annular member which constitutes the constant velocity joint concerning this embodiment. It is a partial cross section perspective view of the annular member which consists of other structures of the constant velocity joint which concerns on this embodiment. It is sectional drawing of the assembly | attachment state of the trunnion, needle bearing, and roller member which comprise the constant velocity joint which concerns on this embodiment. It is a principal part expanded sectional view of the constant velocity joint which concerns on this embodiment. It is principal part sectional drawing of the constant velocity joint which concerns on other embodiment. It is principal part sectional drawing of the constant velocity joint which concerns on other embodiment. It is principal part sectional drawing of the constant velocity joint which concerns on other embodiment. It is a side surface schematic diagram of the constant velocity joint which concerns on this embodiment. It is a front schematic diagram of the constant velocity joint which concerns on this embodiment. It is a partial cross section figure of the constant velocity joint which concerns on a prior art. It is principal part sectional drawing of the constant velocity joint which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 ... Constant velocity joint 32 ... Outer member 34 ... Inner member 36 ... Guide groove 42 ... Spider 44 ... Trunnion 45 ... Cylindrical part 46 ... Needle bearing 47 ... Base end part 48 ... Roller member 50, 54, 64, 66 ... Ring member 60 ... Flange

Claims (5)

A plurality of guide grooves that are spaced apart by a predetermined distance and extend along the axial direction are provided on the inner peripheral surface, and are inserted into a cylindrical outer member that is connected to one of the transmission shafts, and an inner space where the outer member opens. And a constant velocity joint having an inner member connected to the other transmission shaft,
The inner member is
A plurality of trunnions bulging toward the guide groove;
A ring-shaped roller member that contacts the guide groove and is externally fitted to the trunnion;
A plurality of rolling elements interposed between the trunnion and the roller member so as to freely roll;
With
On the inner peripheral part of the roller member, a flange part is formed which is formed on the end side in the bulging direction of the trunnion and projects radially inward, and circulates along the inner peripheral part.
An annular member is attached to the base end side of the trunnion,
The constant velocity joint, wherein the rolling element is held between the flange portion and the annular member. The constant velocity joint according to claim 1,
The constant velocity joint according to claim 1, wherein the annular member is chamfered at a portion that contacts the proximal end portion of the trunnion. The constant velocity joint according to claim 1,
A constant velocity joint characterized in that a gap is set between the annular member and the rolling element to ensure a predetermined amount of movement of the roller member along the axial direction of the trunnion. The constant velocity joint according to claim 1,
The annular member is disposed in proximity to an end surface of the roller member that is separated from the flange portion, and the predetermined movement of the roller member along the axial direction of the trunnion is between the annular member and the end surface. A constant velocity joint characterized in that a gap for securing the amount is set. The constant velocity joint according to claim 1,
The ratio of the radius of curvature of the outer peripheral surface from the cylindrical portion of the trunnion to which the roller member is fitted to the base end portion to the diameter of the cylindrical portion is set in the range of 0.05 or more and 0.35 or less. Constant velocity joints characterized in that

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