JPH07103250A - Tripod type uniform speed universal joint - Google Patents

Abstract

PURPOSE:To smooth the motion of a roller inside a track groove so as to suppress friction, vibration, heat generation, and noise even when an operating angle is taken against the track groove accepting a leg shaft and a guiding roller on the outer circumference of the leg shaft in a tripod type uniform speed universal joint. CONSTITUTION:In a track groove 12, which is arranged inside an outer ring 10 provided with the second shaft 11, an angle beta, which the center line of the track groove 12 makes with the shaft center X, and an angle alpha, which a leg shaft 19 arranged in a tripod member 14 installed in the inside makes with the shaft center X, satisfy such a formula as tanbeta=2tanalpha.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tripod type constant velocity universal joint used in automobiles and the like.

[0002]

2. Description of the Related Art Tripod type constant velocity universal joints are often used in front-wheel drive type automobiles because of their advantages of ensuring a large working angle and plunging distance. As one having a principle structure of such a tripod type constant velocity universal joint, for example, one shown in FIG. 6 is known. The illustration shows three cylindrical track grooves 2 in the axial direction on the inner surface of the outer ring 1.
Forming a radial leg shaft 4 on the tripod member 3 disposed inside the outer ring 1, and fitting the spherical roller 5 on the outer side of each leg shaft 4 so as to be rotatable and axially slidable. The spherical rollers 5 are engaged with the roller guide surfaces 6 on both sides of the track groove 2. Figure 7 is an illustration of the orbital plane,
FIG. 8 is a schematic perspective view of the mechanism.

Further, in addition to the examples of the above-mentioned general structure, they are disclosed in, for example, US Pat. Nos. 5,135,438, JP-B-2-32492, and JP-B-5-9534. There is something.

The basic structure of the universal joint according to the above-mentioned US Patent is the same as that of the above-mentioned general publicly known example, but in particular, the leg shaft has a slight angle from the plane perpendicular to the axial center of the first shaft fixing it. Mounted in a plane inclined in the positive or negative direction respectively, and mounted on the leg shaft along a straight line that intersects at a second slight angle with a straight line that intersects at right angles with the center line of this diagonally mounted leg shaft. The difference is that a track groove is provided so that the spherical roller can roll freely.

In the above-mentioned Japanese Patent Publication, three track grooves in the axial direction are formed on the inner surface of the outer ring, and three cylindrical leg shafts are provided on the tripod member arranged inside the outer ring. A constant velocity universal joint in which a roller rotatably fitted to the outside of each leg shaft is arranged between the roller guide surfaces on both sides of the track groove to transmit the rotational movement between the outer ring and the tripod member. In particular, the roller guide surface of the track groove is a plane parallel to the plane including the axis of the outer ring and the track groove center, the roller is cylindrical, and the axis of the outer diameter surface is between the cylindrical roller and the leg shaft. On the other hand, a tilted ring whose inner diameter surface is tilted is rotatably incorporated.

Further, in the utility model publication, three track grooves in the axial direction are formed on the inner surface of the outer ring, and the three tripod members arranged inside the outer ring are provided with three cylindrical leg shafts. A constant velocity universal joint in which a spherical roller rotatably fitted to the outside of each leg shaft is arranged between the roller guide surfaces on both sides of the track groove to transmit the rotational movement between the outer ring and the tripod member. In particular, the axis of the leg shaft is inclined with respect to the vertical plane that intersects the axis of the tripod member.

[0007]

By the way, in the case of the first known example described above, considering the case where the rotational force is transmitted in a state where the outer ring 1 and the tripod member 3 make an operating angle, each spherical roller 5 is considered. The roller guide surface 6 of the cylindrical track groove 2 and the roller guide surface 6 of the cylindrical track groove 2 cross each other obliquely as shown in FIGS. 6 and 7, and the spherical roller 5 cannot be caused to perform a correct rolling motion. That is, the spherical roller 5 tries to roll in the direction shown by the arrow (a) in FIG. 6, while the track groove 2 is cylindrical and parallel to the axis of the outer ring 1, so the spherical roller 5 Will move while being restrained by the track groove 2. As a result, a slip occurs between the roller guide surface 6 of the track groove 2 and the spherical roller 5 to generate heat, and this slip induces a thrust force in the axial direction, which causes vibration.

In the constant velocity universal joints disclosed in the publications other than the above-mentioned first known example, heat generation, vibration or noise due to the above-mentioned slippage occurs, so that the respective problems are solved by the above-mentioned constitution. Some have been made, but are still insufficient to solve all the above problems.

Further, although the publications other than the first known example are, in principle, constant velocity universal joints that transmit constant-velocity rotations, the working angle (bending angle) of the first shaft and the second shaft is particularly large. There is also a problem in that the constant velocity cannot always be ensured at all rotational phase angles when taken.

In view of the problems involved in the above-mentioned conventional tripod type constant velocity universal joint, the present invention forms the angle between the track groove for receiving the leg shaft and the guide roller on the outer periphery thereof and the respective reference lines. Even when the working angle is set by setting a predetermined angular relationship, constant velocity is ensured, and the movement of the guide roller in the track groove is smoothed so that friction, vibration, heat generation and noise can be effectively suppressed. It is an object to provide a universal joint.

[0011]

As a means for solving the above problems, the present invention has three track grooves in the axial direction formed on the inner surface of an outer ring, and a tripod member arranged inside the outer ring has three legs. A tripod type in which a shaft is provided in a projecting manner and rollers rotatably fitted to the outside of each leg shaft are arranged between the roller guide surfaces on both sides of the track groove to transmit the rotational movement between the outer ring and the tripod member. In a constant velocity universal joint, the leg shaft is inclined at a first inclination angle with respect to a plane perpendicular to the axis of the tripod member, and a guide groove for the outer ring is provided in a predetermined angle direction with the inclined leg shaft, and the center of the guide groove is formed. The tangent value of the second inclination angle formed by the axis and the axial direction of the tripod member is twice the tangent value of the first inclination angle.

[0012]

In the constant velocity universal joint of the present invention configured as described above, the relationship of tan β = 2 tan α is established, where α is the first inclination angle and β is the second inclination angle. In this case, as shown in FIG. 3, if α is positive, β is positive, and if α is negative, β is negative.

When a certain angular relationship is established between the angle formed by the leg shaft and the angle formed by the central axis of the guide groove, when the roller fitted to the leg shaft moves in the guide groove, the roller guide is formed. The frictional force acting on the surface is minimized, heat generation, vibration, and noise are effectively suppressed, and the rotational force is transmitted extremely smoothly.

The reason why the above relationship is established between the inclination angles α and β is as follows.

The conditions which the guide groove of the outer ring of the tripod type universal joint in which the axis of the tripod member is inclined as shown in FIG. 4 should be determined as follows. Set the coordinate thread of the universal joint and the symbol to be used as follows. The origin of the coordinates is the intersection of the three leg axes of the tripod member. The y-axis is the direction of the shaft when the bending angle is 0 °. The x-axis is horizontal and the z-axis is vertical (see FIG. 5A). The bending of the universal joint shall rotate the shaft in the zy plane, ie around the x-axis. Therefore, the central axis of the outer ring is
It will always be kept parallel to the y-axis. Rotation of the universal joint begins and one of the three axes of the tripod member is yz
Put it on the part of z> 0 on the plane and measure from there.

Α: Inclination angle of shaft of tripod member β: Inclination angle of guide groove of outer ring θ: Rotation angle of universal joint φ: Bending angle of universal joint γ: P. of center line of guide groove of outer ring C. R (s.t): x, z coordinates of the center of the outer ring I: origin l. m. n: Center line of outer race guide groove P. R. Q: Intersection of the axis of the tripod member and l, m, n The conditions of the guide groove are advanced in the following procedure.

(1) Formulas of three axes of the tripod member at a rotation angle of 0 ° and a bending angle of 0 ° are obtained.

(2) Formulas for the three center lines of the guide groove of the outer ring when the rotation angle is 0 ° and the bending angle is 0 ° are obtained.

(3) Formulas for the three axes of the tripod member when the rotation angle is θ ° and the bending angle is φ ° are calculated.

(4) The formulas of the three center lines of the guide groove of the outer ring when the rotation angle is θ ° and the bending angle is φ ° are obtained (actually, the θ rotation is performed and the s and z axes are set in the x axis direction). Translated in the direction t).

(5) Three relational expressions relating to s and t are obtained.

(6) A condition for not making s and t indefinite is obtained.

As for the formula of the straight line IP, referring to FIG. 5 (b), if x = 0 z = (1 / tan α) · y (1) tan α = g, then x = 0 y-gz = 0 (2 ) The straight line IR is obtained by rotating the straight line IP by 2π / 3 around the y axis (see (a) of FIG. 5). Coordinate transformation x = (1/2) · (−x ′ + √3z ′) z = (1/2) * (-√3x'-z ') (3) is substituted for (2). The symbol √3 will be used hereinafter to mean the route of the numeral 3. When taking primes and arranging them, x−√3z = 0 √3gx + 2y + gz = 0 (4) Similarly, the straight line IQ is −2π / about the straight line IP around the y axis.
Since it is rotated three times, the coordinate conversion x = (1/2) · (−x′−√3z ′) z = (1/2) · (√3x′−z ′) (5) is converted into (2) It is obtained by substituting into Since it is an inversion of the sign before √3 in the formula (4), x + √3 = 0−√3gx + 2y + gz = 0 (6) The formula of the straight line l is as shown in (c) of FIG. z =-(tan β) y + r (7) If tan β = h, x = 0 hy + z = r (8) Since the straight line m is obtained by rotating 1 around the y axis by 2π / 3, x−√3z = 0-√3x + 2hy-z = 2r (9) Since the straight line n is obtained by rotating l by -2π / 3 around the y-axis, x + √3z = 0 √3x + 2hy-z = 2r (10) (3) Free Angle θ when the joint shaft is broken
In order to obtain an expression representing the straight line IP in an arbitrary rotated state, the straight line IP is rotated by θ around the y axis and φ around the x axis. Coordinate conversion to equation (2)

[0024]

[Equation 1]

Perform sin θ = a, cos θ = b, s
If we put inφ = c and cosφ = d, the above transformation is x = bx ′ −acy ′ + adz ′ y = dy ′ + cz ′ (11) z = −ax ′ −bcy ′ + bdz ′ For x, y and z, Since there is a relation of the equation (2), when substituting it and taking a prime, the relation of the following equation is obtained.

Bx-acy + adz = 0 agx + (d + bcg) y + (c-bdg) z = 0 (12) When the same conversion is performed on the straight line IR, (√3a + b) x + (-ac + √3bc) y + (ad −√3bd) z = 0 (-ag + √3bg) x + (-√3acg + 2d-bcg) y + (√3adg + 2c + bdg) z = 0 (13) If the same conversion is performed on the straight line IQ, If the sign is reversed, (-√3a + b) x + (-ac-√3bc) y + (ad + √3bd) z = 0 (-ag-√3bg) x + (√3acg + 2d-bcg) y + (-√3adg + 2c + bdg) z = 0 (14) (4) Rotate the straight line l by θ around the y-axis and move s in the x-axis direction.
Translates t in the z-axis direction. If the coordinate transformation x = b (x'-s) + a (z'-t) z = -a (x'-s) + b (z'-t) (15) is applied to the equation (7), bx + az = bs + at- ax + hy + bz = −as + bt + r (16) When the same conversion is performed on the straight line m, (√3a + b) x + (a−√3b) z = (√3a + b) s + (a−√3b) t (a−√) 3b) x + 2hy + (-√3a-b) z = (a-√3b) s + (-√3a-b) t + 2r (17) When the same conversion is applied to the straight line n, (-√3a + b) x + (a + √3b) z = (-√3a + b) s + (a + √3b) t (a + √3b) x + 2hy + (√3a-b) z = (a + √3b) s + (√3a-b) t + 2r (18) ( 5) Since the straight lines IP, IR, IQ and l, m, n have been obtained in the above, the coordinates of the points P, Q, R are obtained from them.

The coordinates of the point P are obtained from the three expressions of the first expressions of the points (12) and (16).

[0028]

[Equation 2]

Equation (19) must naturally satisfy the second equation of equation (16). Then, substituting (19) into the second equation of equation (16) and rearranging, we obtain (-b ² ch + bdgh + bd + cg) s + (a-abch + adgh) t = (abd + acg-ab) r (20). By this, one relational expression of s same as above t was obtained.

The coordinates of the point R are obtained from the three equations of equations (13) and (17).

To avoid complicated expressions, a-√3b
= A, √3a + b = B, (13) is Bx-Acy + Adz = 0-Agx + (2d-Bcg) y + (2c + Bdg) z = 0 (21) (17) is Bx-Az = Bs + AtAx + 2hy-Bz = As -Bt + 2r (22) From the first equation of (21) and (22)

[0032]

[Equation 3]

Substituting equation (23) into the second equation of (22) and rearranging, (-B ² ch-2Bdgh-2Bd + 4cg) s + (-ABch-2Adgh-2A) t = (ABd-2Acg-AB ) r (24) This is the second relational expression regarding s and t. Similarly,
In equations (14) and (18), if a + √3b = E and −√3a + b = F, then Fx −Ecy + Edz = 0−Egx + (2d−Fcg) y + (2c + Fdy) z = 0 (25) Fx + Ez = Fs + Et Ex + 2hy-Fz = Es -Ft + r, which are similar to the equations (21) and (22), respectively, the third relational expression of s and t obtained from the point Q is (-F ^{2 ch -2Fdhg -2Fd + 4cg) s} + (- a EFch-2Edhg -2E) t = ( EFd -2Ecg-EF) r (26).

(6) Since there are three relational expressions with respect to s and t, the necessary condition for preventing s and t from becoming indefinite is that the three expressions are first-order dependent. As a starting point for obtaining the condition, the sum of both sides of (24) and (26) is made.
Returning A, B, E and F, {-(3a ² + b ² ) ch -2bdgh-2bd + 4cg} s + (2abch-2adgh-2a) t = -2 (abd + acg -ab) r (27) is obtained. To be The right side of (27) is twice the size of the right side of (20),
Only the signs are reversed. Then (27) + 2 (20)
Is calculated as {-(3a ² + b ² ) ch -2bdgh-2bd + 4cg +2 (-b ² ch + bd
gh + bd + cg)} s + {2abch-2adgh-2a + 2 (a-abc
h + adgh)} t = 0, and eventually (-ch + 2cg) s = 0 is obtained. Therefore, h = 2g must be satisfied for the equations (20), (24), and (26) to be linearly dependent. From this, tanβ = 2tanα
Is obtained.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main sectional view showing a tripod type constant velocity joint of the embodiment. In the illustrated constant velocity joint, the outer ring 1
In the same manner as in the conventional case, the second shaft 11 is integrally provided at the closed end, and three track grooves 12 in the axial direction are formed on the inner peripheral surface at intervals of 120 ° around the central axis. There is. Each track groove 12 has two roller guide surfaces 13 on both sides, and the center line of the track groove is provided so as to be inclined at a predetermined small angle with respect to the center axis.

The tripod member 14 inserted into the outer ring 10 is engaged with the serration 16 formed at one end of the first shaft 15 and is held in a retaining state between the step portion 17 and the clip 18. To be done. The tripod member 14 has three columnar leg shafts 19, and each leg shaft 19 is obliquely provided at a first angle α with respect to a plane perpendicular to the central axis. A roller 20 having a spherical outer peripheral surface is rotatably fitted to each leg shaft 19 and is prevented from coming off by a clip 21. Reference numeral 19a is a pedestal base.

The roller guide surface 13 of the track groove 12 into which the spherical roller 20 is fitted is formed as a curved surface corresponding to the spherical roller 20. Further, if the second angle of the center line of the track groove is β with respect to the first angle α of the leg portion 19, α and β are determined so that the relationship of tan β = 2tan α is established.

FIG. 2 shows an example in which α and β are set in opposite directions to those in the case of FIG. Except for the above, the configuration is the same as in the case of FIG. The relationship between α and β is shown in FIG. 3 for easy understanding.

Next, the operation of the above embodiment will be described. When the operating angle between the second shaft 11 and the first shaft 15 is 0 degree,
The rotation between the two is transmitted via the roller guide surface 13 of the track groove 12 and the roller 20 engaged with the roller guide surface 13. In this case, if plunging occurs due to the relative movement of the two,
The roller 20 rotates, and the roller guide surface 1 of the track groove 12
Roll along 3 At this time, the outer peripheral surface of the roller 20 moves while making point contact with the roller guide surface 13, and the movement moves parallel to the center line of the track groove 12. The center line and the leg shaft 19 are maintained at a position close to a right angle even if there are inclinations of the angles α and β in the above relationship, the frictional force due to rolling is sufficiently suppressed, and the movement is extremely smooth. Almost no vibration or heat generation. Of course, the first shaft 15 and the second shaft 11 rotate at a constant speed.

Even when the operating angle φ is generated between the first shaft 15 and the second shaft 11, the leg shaft 19 rotates around the axis X, and at the time of rotation, the leg shaft 19 is positioned in the track groove 12 relative to the outer ring 10. Sliding motion occurs. The sliding motion reciprocates back and forth in the track groove 12 around the intersection of the center line of the leg shaft 19 and the center line of the track groove 12 in the figure, and the roller 20 rolls at that time.

The rolling of the roller 20 is the same as the rolling by plunging when the operating angle is 0, and this rolling is repeated, but as described above, the center line of the track groove 12 is as described above. Since the angles α and β are obliquely provided in a rational constant relationship, the frictional force is small, and the vibration, heat generation, and noise are small. This is an arbitrary working angle φ,
Even if the universal joint rotates at an arbitrary angle θ, the leg shaft 19
This is because the intersection of the center line of the track groove 12 and the center line of the track groove 12 always exists in a reasonable state, and a point contact point between the roller 20 and the roller guide surface 13 is generated corresponding to the movement of this intersection.

[0042]

As described in detail above, in the constant velocity universal joint of the present invention, tanβ = 2tanα between the first inclination angle α formed by the leg shaft and the second inclination angle β formed by the central axis of the guide groove. Since the relationship is established, the intersection of the central axis of the leg shaft and the guide groove always exists in the geometrical shape even when the working angle φ and the rotation angle θ are arbitrary, and the roller fitted to the leg shaft is Since the movement locus in the guide groove of the above satisfies the above relational expression, its movement is naturally much smoother than the conventional constant velocity universal joint that does not satisfy the above relational expression, and the frictional resistance due to rolling and There are advantages that various problems such as vibration, heat generation, and noise are suppressed to a minimum, and a constant velocity universal joint that is almost ideal is obtained, such as maintaining constant velocity even at a large operating angle.

[Brief description of drawings]

FIG. 1 is a main sectional view of a constant velocity universal joint according to a first embodiment.

FIG. 2 is a main sectional view of a constant velocity universal joint according to a second embodiment.

FIG. 3 is an explanatory diagram of inclination angles α and β.

FIG. 4 is an explanatory view of the inclination of the leg shaft of the constant velocity universal joint.

FIG. 5 is an explanatory diagram of a relationship between rectangular coordinates, leg axes IP, IR, IQ, and a center line 1 of a guide groove.

FIG. 6 is a main sectional view of a conventional constant velocity universal joint.

FIG. 7 is a schematic view of the rolling surface of the above.

[Fig. 8] Functional diagram of the above

[Explanation of symbols]

 10 Outer ring 11 Second shaft 12 Track groove (guide groove) 13 Roller guide surface 14 Tripod member 15 First shaft 16 Serration 17 Step portion 18 Clip 19 Leg shaft 20 Roller

Claims (1)

[Claims] 1. An outer ring is formed with three axial track grooves, and a tripod member arranged inside the outer ring is provided with three leg shafts so as to be rotatable outside each leg shaft. In a tripod type constant velocity universal joint in which the fitted rollers are arranged between the roller guide surfaces on both sides of the track groove to transmit the rotational movement between the outer ring and the tripod member, the leg shaft is the axis of the tripod member. To the surface perpendicular to the first inclination angle, and the guide groove of the outer ring is provided in a predetermined angle direction with the inclined leg shaft, and the second inclination angle formed by the central axis of the guide groove and the axial direction of the tripod member. The tangent value of is 2 of the tangent value of the first tilt angle
A tripod type constant velocity universal joint characterized by being doubled.