JPH09324822A - Tripod type constant velocity joint - Google Patents

Abstract

(57) [Abstract] [Purpose] During transmission of rotational force with a joint angle, the axial force applied to the rotating shaft to which the tripod 5 is fixed via the trunnion 8 is reduced to suppress the occurrence of vibration. . [Structure] During transmission of a rotational force, the outer peripheral surface of the roller 9 performs a swinging motion while being in contact with the guide surface 11 on the anchor side. The radius of curvature R ₂ of the central rolling surface portion 12 with which the outer peripheral surface of the roller 9 abuts at the central portion in the width direction of the guide surface 11.
Is made sufficiently larger than the radius of curvature R ₀ of the outer peripheral surface of the roller 9. Further, the rollers 9 are provided on both sides of the central rolling surface portion 12.
The radius of curvature R ₀ equal to or slightly larger curvature than the radius of curvature R ₀ to the radius R ₁ of the outer peripheral surface, the guide surface portion 1 having R ₁
3 and 13 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The tripod type constant velocity joint according to the present invention is incorporated in a drive system of an automobile, for example, and is used for transmitting a rotational force between rotating shafts existing in a non-linear manner.

[0002]

2. Description of the Related Art A tripod type constant velocity joint has been widely used as a kind of constant velocity joint incorporated in a drive system of an automobile. For example, JP-A-63-18603
6 and 62-233522, FIGS.
A tripod type constant velocity joint 1 as shown in FIG. The constant velocity joint 1 includes a hollow cylindrical housing 3 fixed to an end portion of a first rotating shaft 2 such as a drive shaft,
It is composed of a tripod 5 fixed to the end of the second rotary shaft 4 such as a wheel-side rotary shaft. Concave portions 6, 6 are provided at three positions on the inner peripheral surface of the housing 3 at equal intervals in the circumferential direction.
Each is formed from the inner peripheral surface toward the outside in the diametrical direction of the housing 3.

On the other hand, the tripod 5 fixed to the end of the second rotating shaft 4 is composed of a boss 7 for fixing the end of the second rotating shaft 4 and an outer peripheral surface of the boss 7. It is composed of trunnions 8 formed at three positions at equal intervals in the circumferential direction. Around each of these trunnions 8, 8 each formed in a cylindrical shape, rollers 9, 9 are respectively supported via needle bearings 10 so as to be rotatable and slightly displaceable in the axial direction. . The constant velocity joint 1 is formed by fitting these rollers 9 into the recesses 6 on the inner peripheral surface of the housing 3.
The pair of guide surfaces 11, 11 forming the recesses 6, 6 are cylindrical concave surfaces.
The outer peripheral surfaces of the rollers 9 and 9 are spherical convex surfaces. The radius of curvature of each guide surface is slightly larger than the radius of curvature of the outer peripheral surface of each roller. Therefore, the rollers 9, 9 are rotatably and swingably supported between the guide surfaces 11, 11 provided in pairs for each of the recesses 6, 6.

When the constant velocity joint 1 constructed as described above is used, for example, when the first rotary shaft 2 rotates, this rotational force is transferred from the housing 3 to the rollers 9, 9, and the needle bearing 1.
0, trunnion 8, 8 to the boss 7 of the tripod 5. Then, the second rotating shaft 4 having the boss 7 fixed to the end is rotated. Further, when the central axis of the first rotary shaft 2 and the central axis of the second rotary shaft 4 do not match (when there is a joint angle in the constant velocity joint 1), both rotary shafts 2 and 4 are With the rotation, each of the above trunnions 8,
8 is displaced with respect to the guide surfaces 11, 11 of the recesses 6, 6 in a direction of swinging about the tripod 5 as shown in FIGS. At this time, each of the trunnions 8 and 8
The rollers 9, 9 supported around the
While rolling on the guide surface of each of the trunnions 8,
8 is displaced in the axial direction. As is well known, due to these movements, constant velocity between the first and second rotary shafts 2 and 4 is ensured.

In the case of the constant velocity joint 1 configured and operating as described above, when the first and second rotary shafts 2 and 4 are rotated in the state where the joint angle exists, the rollers 9 and 9 described above are rotated.
Moves along the guide surfaces 11, 11 while changing the direction of the housing 3 in the axial direction, and is displaced in the axial direction of the trunnions 8, 8. That is, when the trunnions 8, 8 swing about the boss portion 7 in the presence of the joint angle, the rollers 9, 9 are moved to the above-mentioned positions as shown by the arrow α in FIG. The housing 3 tends to be displaced not only in the axial direction but also in the diametrical direction. However, each of the guide surfaces 11 and 11 is a cylindrical concave surface, and each of the rollers 9 and
Since the outer peripheral surface of 9 is a spherical convex surface, these rollers 9, 9
Seldom displaces in the diameter direction of the housing 3.

Therefore, when the tripod type constant velocity joint having the conventional structure shown in FIGS. 5 and 6 is operated with a joint angle, each of the rollers 9 has a guide surface 11 as shown in FIG. With respect to the guide surface 11, the guide surface 11 is displaced in the longitudinal direction. As a result, each of the rollers 9
Tends to be displaced in the axial direction of the trunnion 8 with respect to the trunnion 8 supporting the roller 9.
Along with this displacement, a force extending in the axial direction is applied to the second rotating shaft 4 via the trunnion 8 and the boss portion. When this force is increased, an unpleasant vibration called judder is generated along with the operation of the tripod, which gives an occupant an uncomfortable feeling. That is, the greater the force, the more likely the vibration is to occur, and the greater the vibration generated.

The positional relationship between the contact points due to the axial force applied to each trunnion 8 during operation of the conventional tripod type constant velocity joint shown in FIGS. 5 and 6 will be described with reference to FIG. In FIG. 8, R ₀ is the radius of curvature of the spherical surface forming the outer peripheral surface of the roller 9, R ₁ is the radius of curvature of the cross section of the guide surface,
(R ₁ −R ₀ ) is the difference between these two radii of curvature. This difference (R ₁ −R ₀ ) is small in the actual case, and is shown in FIG.
Is exaggerated for clarity. Further, R is a contact point where the outer peripheral surface of the roller 9 and the guide surface 11 contact each other when the roller 9 is in the neutral position. Further, γ _S is the outer peripheral surface of the roller 9 and the guide surface 11
Represents the contact angle with. The contact angle γ _S is the contact point S at which the outer peripheral surface of the roller 9 contacts the guide surface 11 and the guide surface 11 when the roller 9 is in the neutral state.
Is a crossing angle between a straight line a connecting the center point O _{S of the} curvature of the cross section and a straight line b connecting the contact point R in the neutral state and the center point O _S. Further, Δ is the displacement amount of the center point of the curvature of the roller 9 and the outer peripheral surface of the roller 9. That is, when the contact angle is γ _S , the center point of the curvature of the outer peripheral surface of the roller 9 is from O ₁ to O existing at the neutral position.
₁ ". Move to the geometrically clearly shown, both of these center points O _1, O _1" Both, centered on the center point O _S curvature of the cross section of the guide surface, the radius (R ₁ - R ₀ ). The points O _S , O ₁ ″, and S are on the same straight line B, and the points O _S , O ₁ , and R are on the same straight line B. The displacement Δ is the axis of the trunnion 8. The distance between these center points O ₁ and O ₁ ″ in the direction is about 0.02 mm in the case of an actual tripod type constant velocity joint incorporated in an automobile. Further, θ ₀ is the intersection angle between the joint angles {= the first and second rotation axes 2 and 4 (see FIGS. 5 to 6). See FIG. 3 to illustrate the invention. }, And θ is an operating angle that is an angle (see FIG. 3) in which the trunnion is inclined from the neutral position.

As shown in FIGS. 5 and 6, when the tripod type constant velocity joint is operated with a joint angle of θ ₀ , the roller 9 moves toward the anchor side (when the rotational force is transmitted, the roller 9 is As shown in FIG. 3 for explaining the present invention, the guide surface 11 (on which the outer peripheral surface of each roller is pressed) tends to perform an arc motion about the center point O _{J of the} tripod. Accordingly, the oblique angle, which is the deviation between the direction in which the roller 9 is about to roll and the direction of the cylindrical concave guide surface 11, changes every moment as the operating angle θ changes, and the operating angle θ becomes large. The greater the angle of intersection, the greater. However, since the guide surface 11 is formed into a cylindrical concave surface, the roller 9 cannot perform an arc motion centering on the center point O _{J of the} tripod. That is, the roller 9 is only displaced by Δ in the axial direction of the trunnion 8 due to the gap (play) between the pair of guide surfaces 11 and 11 and the outer peripheral surface of the roller 9. With the displacement of Δ, the contact point between the outer peripheral surface of the roller 9 and the guide surface 11 moves from the contact point R, which is the neutral position, to the contact point S, and the outer peripheral surface of the roller 9 The contact angle with the guide surface 11 is γ _S. As is clear from FIG. 8 described above, the contact angle γ _S becomes considerably large even when the displacement amount Δ is small.

[0009] In addition, at the time of operation of the tripod type constant velocity joint, such a contact angle γ _S and lead displacement △ in the contact angle γ _S, determined in the following manner. Roller 9
Is the above trunnion 8 and needle bearing 10 (see FIG. 6)
The trunnion 8 is supported rotatably via the shaft and is displaceable in the axial direction of the trunnion 8. However, since a large radial load is applied to the needle bearing at the time of transmitting the rotational force by the tripod type constant velocity joint, the rolling surfaces of the plurality of needles constituting the needle bearing, the outer peripheral surface of the trunnion 8 and the roller. A certain large frictional force acts on the inner peripheral surface of the groove 9. Therefore, in order to displace the roller 9 in the axial direction of the trunnion 8, it is necessary to overcome this frictional force. On the other hand, the force for displacing the roller 9 in the axial direction of the trunnion 8 is that the outer peripheral surface of the roller 9 riding on the guide surface 11 tends to slide down to the central portion in the width direction of the guide surface 11. Caused by. Therefore, the contact angle γ _S and the displacement Δ are maintained in a state where the frictional force and the force of the outer peripheral surface of the roller 9 attempting to slide down to the central portion in the width direction of the guide surface 11 are balanced.

By the contact angle γ _S and the oblique angle determined in this way, the angle at which the roller 9 tries to rise toward the end portion in the width direction at the contact position is raised. Let β be the angle. The larger the rising angle β, the larger the force applied from the roller 9 to the second rotary shaft 4 via the trunnion 8 in the axial direction of the second rotary shaft 4. The rising angle β is represented by the following equation (1). beta = sin ^{-1 [sin {tan -1 (tanθ / cosγ} S)} · sinγ S ] - (1) based on the equation (1), parsley for the conventional structure shown in FIGS. 5-8 Rise angle β, operating angle θ = 16 °, γ _S
= 15 °, β≈4.224 °.
This value cannot be said to be small in terms of suppressing the vibration generated during the operation of the tripod type constant velocity joint.

As a technique for suppressing the vibration caused by the above-mentioned causes, Japanese Patent Laid-Open No. 61-116126 discloses that
Compared with the radius of curvature of the spherical surface that constitutes the outer peripheral surface of each roller,
A technique is disclosed in which the radius of curvature of the cross section of the guide surface with which the outer peripheral surface of each of these rollers abuts is made sufficiently large. However, in the case of the technique described in this publication, when the rollers are displaced in the axial direction of the trunnion, the outer peripheral surfaces of the rollers are not only the guide surface on the anchor side but also the anti-anchor side (rotational side). When the force is transmitted, the outer peripheral surface of each roller also contacts the guide surface on the side where it is not pressed. In this way, when the outer peripheral surface of each of the rollers comes into contact with the guide surfaces of both the anchor side and the opposite anchor side (two-point contact), the resistance against the rotation of these rollers increases, and in the extreme case, Each of these rollers locks (makes it unable to rotate) within the housing.

If the distance between the pair of guide surfaces opposed to each other is made sufficiently larger than the outer diameter of each roller, it is possible to prevent each roller from contacting the guide surfaces at two points, and to prevent the locking of the lock. Occurrence can be prevented. However, if the difference between the outer diameter of each roller and the distance between the pair of guide surfaces is increased in this way, the play (backlash) in the rotational direction of the tripod type constant velocity joint increases. Then, for example, when shifting from an acceleration state to a deceleration state by engine braking, or vice versa, the tapping sound generated inside the tripod type constant velocity joint becomes large, causing a problem such as giving an occupant discomfort. To do.

[0013]

SUMMARY OF THE INVENTION In view of the above situation, the present invention generates an unpleasant vibration when operating with a large joint angle without increasing the backlash. The present invention was made in order to provide a tripod type constant velocity joint that does not have the above.

[0014]

The tripod type constant velocity joint of the present invention is, like the above-described conventional tripod type constant velocity joint, fixed at the end of the first rotary shaft and having an opening at one end in the axial direction. The hollow cylindrical housing, the three recesses formed on the inner peripheral surface of the housing at equal intervals in the circumferential direction, and the inner surface of each of the recesses facing each other. In the axial direction, a pair of cylindrical guide surfaces, one pair for each recess, and three trunnions that enter the above three recesses are circumferentially formed on the outer peripheral surface. The tripods, which are fixed at equal intervals and are fixed to the end of the second rotating shaft, are rotatably supported on the outer peripheral surfaces of the trunnions, respectively, and are supported so as to be slightly displaced in the axial direction of the trunnions. Also, each outer peripheral surface is a spherical convex surface. Comprising three and a roller.

Particularly, in the tripod type constant velocity joint of the present invention, at least the guide surface on the anchor side has a central rolling surface portion and a pair of guide surface portions. The central rolling surface portion is provided in the central portion in the width direction of each guide surface and has a radius of curvature sufficiently larger than the radius of curvature of the outer peripheral surface of each roller. The pair of guide surface portions are provided on both side portions in the width direction of each guide surface, and each has a curvature radius equal to or slightly larger than the radius of curvature of the outer peripheral surface of each roller. And
Both widthwise end edges of the central rolling surface portion and end edges of the respective guide surface portions are smoothly continuous.

[0016]

The tripod-type constant velocity joint of the present invention constructed as described above is provided between a housing fixed to the end of the first rotating shaft and a tripod fixed to the end of the second rotating shaft. The operation itself when transmitting the rotational force is the same as that of the above-described conventional or prior art tripod type constant velocity joint.

Particularly, in the tripod type constant velocity joint of the present invention, the radius of curvature of the central rolling portion provided in the central portion in the width direction of the guide surface is made sufficiently larger than the radius of curvature of the outer peripheral surface of the roller. The degree to which the roller rises on the guide surface due to the transmission of the rotational force is suppressed (the rise angle becomes smaller). As a result, via the trunnion supporting the roller, the force applied in the axial direction to the second rotating shaft to which the tripod is fixed is reduced to reduce the vibration generated during the operation of the tripod type constant velocity joint. Can be suppressed.

Further, in the case of the tripod type constant velocity joint of the present invention, a curvature equal to or slightly larger than the radius of curvature of the outer peripheral surface of each roller is provided on both sides in the width direction of the central rolling portion. Since the guide surface portions having the radius are provided, these guide surface portions restrict the axial displacement of the roller with respect to the trunnion. Therefore, this roller is prevented from being excessively displaced in the axial direction of the trunnion. As a result, it is possible to prevent the outer peripheral surface of the roller from coming into contact with the guide surface on the side opposite to the anchor side without increasing the distance between the guide surfaces provided for each recess, and to prevent backlash. Occurrence can be suppressed.

[0019]

1 to 3 show a first embodiment of the present invention. The feature of the present invention is that the friction acting between the guide surface 11 provided on the housing 3 constituting the tripod type constant velocity joint and the outer peripheral surface of the roller 9 is transmitted when the rotational force is transmitted in the state where the joint angle is added. The point is that the shape of the guide surface 11 is devised in order to reduce the force and the force applied in the axial direction of the trunnion. Since the structure and operation of the other parts are the same as the conventional structure shown in FIGS. 5 to 6, the illustration and description of the equivalent parts will be omitted or simplified, and the characteristic parts of the present invention will be described below. I will explain mainly. The roller 9 is supported by a needle bearing 10 around the trunnion 8 so as to be rotatable and slightly displaceable in the axial direction. The needle bearing 10
The plurality of needles 14, 14 constituting the
5 and the retaining ring 16 prevent the roller 9 from coming out.

In order to construct the tripod type constant velocity joint of the present invention, the guide surfaces 11 and 11 formed in pairs in the concave portions 6 formed at three positions on the inner peripheral surface of the housing 3 so as to face each other. , Each having one central rolling surface portion 12 and a pair of guide surface portions 13, 13. Of these, the central rolling surface portion 12 is the guide surface 11, 1
It is provided between the points P and Q in FIGS. 1 and 2, which is the central portion in the width direction 1 (the left-right direction in FIGS. 1-2 and the up-down direction in FIG. 3). The radius of curvature R ₂ of the central rolling surface portion 12 is sufficiently larger than the radius of curvature R ₀ of the outer peripheral surface of the roller 9 (R ₂ >>
R ₀ ). It should be noted that the central rolling surface portion 12 may be formed at least on the guide surface 11 on the anchor side when the vehicle is moving forward. However, in the tripod type constant velocity joint assembled to the left and right drive wheels, it is preferable that both guide surfaces 11, 11 have the same shape in order to share the parts of the housing 3.

The width dimension B ₀ of the central rolling surface portion 12 as described above.
In the case where the rotational force is transmitted in a state where the intersecting angle of the first and second rotating shafts 2 and 4 (see FIGS. 5 to 6) connected to each other via a tripod type constant velocity joint is maximized. The displacement amount of the locus of the trunnion 8 over the width direction of each of the guide surfaces 11, 11 is substantially matched. That is, when a tripod type constant velocity joint is operated with a joint angle, the locus drawn by one point on the trunnion 8 (corresponding to the PCD of the tripod 5) on the guide surface 11 is:
As shown by the thick solid line a in FIG. 3, the arc has a smaller radius of curvature than the arc centered on the center point O _{J of the} tripod (the locus shown by the thick solid line a is the trunnion stroke due to the eccentric movement of the tripod center). It is a combination of motion and rocking and swiveling motion). When the roller 9 is not displaced in the axial direction of the trunnion 8 relative to the trunnion 8 which makes such an arc motion, the contact position between the outer peripheral surface of the roller 9 and the anchor-side guide surface 11 is the same. The guide surface 11 is displaced in the width direction within the range indicated by B ₁ in the figure.

Further, the pair of guide surface portions 13, 13 are provided on both side portions in the width direction of the guide surfaces 11, 11. Then, the radius of curvature R of each of the guide surface portions 13, 13
_1, R ₁ are each the same or radius of curvature R ₀ of the outer peripheral surface of the roller 9, or is slightly increased (R ₁ ≧ R ₀₎ than the radius of curvature R _0. Then, both widthwise end edges of the central rolling surface portion 12 and the end edges of the respective guide surface portions 12, 12 are smoothly continuous at the points P, Q.

The center points O ₁ and O ₁ ′ of the radii of curvature of the guide surface portions 13 and 13 are substantially on the central axis of the trunnion 8 and the center point O _{S of the} radius of curvature of the outer peripheral surface of the roller 9.
Exists at a position sandwiching from both sides in the axial direction. On the other hand, the center point O _{2 of the} radius of curvature of the central rolling surface portion 12 is
At the center point O _S portion of the radius of curvature of the outer peripheral surface of the existing on an imaginary plane perpendicular to the central axis of the trunnion 8.

As described above, in the tripod type constant velocity joint of the present invention, the radius of curvature R ₂ of the central rolling portion 12 provided in the central portion of the guide surface 11 in the width direction is set to the radius of curvature R ₀ of the outer peripheral surface of the roller 9. Since the roller 9 is made sufficiently larger than the above, it is possible to prevent the roller 9 from rising from the central portion of the guide surface 11 toward the end portion in the width direction having a small inner diameter with the transmission of the rotational force (the rising angle is small. Become). As a result, the force applied to the trunnion 8 supporting the roller 9 in the axial direction can be reduced, and the vibration generated during the operation of the tripod type constant velocity joint can be suppressed.

For example, the radius of curvature R ₀ of the outer peripheral surface of the roller 9 is set to 17.5 mm, and the radius of curvature R ₂ of the central rolling portion 12 is set.
Is 26.25 mm, which is 1.5 times the radius of curvature R ₀ of the outer peripheral surface of the roller 9, and the width B ₀ of the central rolling portion 12 is 2 mm.
Then, the contact angle γ _S is γ _S = sin ⁻¹ (B ₀ / 2R
₂ ) ≈2.183 °. Substituting this value of γ _S into the equation (1) for obtaining the rising angle β, β ≈
It becomes 0.602 °. The operating angle θ was set to 16 ° as in the case of the conventional structure described above.

As described above, according to the tripod type constant velocity joint of the present invention, the second rotary shaft 4 (FIGS. 5 to 6) is passed through each trunnion 8 during operation of the tripod type constant velocity joint.
It is possible to keep the rising angle β small, which is tied to the force applied in the axial direction. Therefore, the force applied in the axial direction can be reduced to suppress the vibration generated during the operation of the tripod type constant velocity joint.

Further, in the case of the tripod type constant velocity joint of the present invention, the central rolling portion 12 is provided on both sides in the width direction,
Each of them has a radius of curvature R _{0 which} is the same as or slightly larger than the radius of curvature R ₀ of the outer peripheral surface of the roller 9.
_{Since the} pair of guide surface portions 13 and 13 having ₁ and R ₁ are provided, the guide surface portions 13 and 13 regulate the axial displacement of the roller 9 with respect to the trunnion 8. Therefore, the roller 9 is prevented from being excessively displaced in the axial direction of the trunnion 8. As a result, it is possible to prevent the outer peripheral surface of the roller 9 from coming into contact with the guide surface 11 on the side opposite to the anchor even if the space between the guide surfaces 11, 11 provided for each recess 6 is not increased. it can. Therefore, even if the backlash is suppressed to a small level, the above-mentioned JP-A-61-1 is used.
Unlike the invention described in Japanese Patent No. 16126, the roller 9 does not contact the inner surface of the recess 6 at two points.

That is, the position of the roller 9 with respect to the axial direction of the trunnion 8 is set with respect to the trunnion 8 by the centrifugal force applied to the roller 9 during operation of the tripod type constant velocity joint under low load or no load. May slide away from the normal position. In the case of the tripod type constant velocity joint of the present invention, even if the position of the roller 9 deviates from the normal position in this way, a force for returning the roller 9 to the normal position is provided during one rotation of the tripod type constant velocity joint. To work. That is, when the position of the roller 9 deviates from the regular position, the outer peripheral surface of the roller 9 comes into contact with one of the pair of guide surface portions 13, 13. The guide surface 13 causes the roller 9 to move,
It is pushed back to the normal position. Therefore, the position of the roller 9 does not remain displaced from the regular position. When the guide surface portion 13 pushes the roller 9 back to the normal position, the second rotary shaft 4 is passed from the roller 9 through the trunnion 8.
(FIGS. 5-6), a relatively large axial force is applied. However, since this force is not applied continuously, it does not result in vibration that causes resonance in other parts.

Next, FIG. 4 shows a second embodiment of the present invention.
An example is shown. In the case of this example, the radius of curvature of the central rolling surface 12 existing in the widthwise central portion of the guide surface 11 is infinite. Therefore, in the case of this example, the central rolling surface 12 is a flat surface. Since the central rolling surface 12 is made flat as described above, the contact angle γ _S obtained by the equation (1) is calculated.
Is 0 °. Therefore, the rising angle β is also 0 °.

Thus, in order to suppress the axial force applied to the trunnion 8 during the operation of the tripod type constant velocity joint, it is preferable to increase the radius of curvature R ₂ of the central rolling surface 12. However, when the radius of curvature R ₂ of the central rolling surface 12 is increased, the central rolling surface 12 and the roller 9 are
When the large torque is transmitted, it becomes difficult to secure the durability of both surfaces of the outer peripheral surface of the outer peripheral surface. On the other hand, if the radius of curvature of the central rolling surface 12 is brought close to the radius of curvature R ₀ of the outer peripheral surface of the roller 9, durability can be ensured by increasing the contact area, but at the time of operation of the tripod type constant velocity joint. The axial force applied to the trunnion 8 increases, and vibration easily occurs. Therefore,
The radius of curvature R ₂ of the central rolling surface 12 is designed and controlled in consideration of the usage of the tripod type constant velocity joint such as the magnitude of torque to be transmitted. The radius of curvature R ₂ of the central rolling surface portion 12 is preferably 1.5 times or more the radius of curvature R ₀ of the outer peripheral surface of the roller 9.

[0031]

The tripod-type constant velocity joint of the present invention is constructed and operates as described above. Therefore, power loss due to friction generated inside is reduced, transmission efficiency is improved, and power transmission is improved. It can also contribute to the reduction of the vibration generated at the time. Also, the frictional heat generated during operation can be suppressed. Moreover, it is only necessary to partially change the shape of the housing, and other parts can use the same ones as before,
There will be no cost increase.

[Brief description of drawings]

FIG. 1 is a partially cut front view showing a first example of an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG. 1, showing a contact state between a guide surface and an outer peripheral surface of a roller, with some parts omitted.

FIG. 3 is a diagram showing a trajectory of a roller on a guide surface, viewed from above in FIG.

FIG. 4 is a view similar to FIG. 2, showing a second example of the embodiment of the present invention;

FIG. 5 is a schematic perspective view showing an example of a conventional tripod type constant velocity joint.

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a partial perspective view showing a relationship between a roller and a guide surface in a state where a joint angle is added.

FIG. 8 is a view similar to FIG. 2, showing a contact state between the guide surface and the outer peripheral surface of the roller in the conventional structure.

[Explanation of symbols]

 1 Constant Velocity Joint 2 First Rotating Shaft 3 Housing 4 Second Rotating Shaft 5 Tripod 6 Recess 7 Boss 8 Trunnion 9 Roller 10 Needle Bearing 11 Guide Surface 12 Central Rolling Surface 13 Guide Surface 14 Needle 15 Locking Ring 16 Retaining ring

Claims (3)

[Claims] 1. A hollow cylindrical housing fixed to an end of a first rotary shaft and having one end in the axial direction opened, and an inner peripheral surface of the housing formed at equal intervals in the circumferential direction. Three concave portions and a cylindrical concave guide surface formed in the inner surface of each of the concave portions, one pair for each concave portion in the axial direction of the housing.
The three trunnions that enter the three recesses are fixed to the outer peripheral surface at equal intervals along the circumferential direction, and the tripods fixed to the end of the second rotating shaft and the trunnions, respectively. In a tripod type constant velocity joint, which is rotatably supported by the outer peripheral surface of each of the trunnions and is capable of being slightly displaced in the axial direction of each trunnion, each roller having three spherical convex surfaces. And, at least the guide surface on the anchor side has a central rolling surface portion having a radius of curvature sufficiently larger than the radius of curvature of the outer peripheral surface of each of the rollers in the widthwise central portion, and each of the widthwise both sides of each of the rollers has a central rolling surface portion. A pair of guide surface portions each having a radius of curvature equal to or slightly larger than the radius of curvature of the outer peripheral surface are provided, and both widthwise end edges of the central rolling surface portion and end edges of the respective guide surface portions are provided. Smoothly Tripod type constant velocity joint, characterized in that is obtained by. 2. A roller extending in the width direction of a guide surface in the case of transmitting a rotational force in a state in which the width dimension of the central rolling surface portion is maximized at the intersecting angle of the first and second rotating shafts. The tripod type constant velocity joint according to claim 1, wherein the tripod type constant velocity joint is substantially matched with the displacement amount. 3. The central rolling surface portion has an infinite radius of curvature, and the central rolling surface portion is a flat surface.
The tripod type constant velocity joint described in.