JPH0235224A - Universal joint - Google Patents

Abstract

PURPOSE:To provide a sufficient twisting strength while decrease in rotational play is achieved by constructing the fitting part of each resin ball having a yoke and a repulsive means with such a profile as to give wedge effect. CONSTITUTION:A universal joint consists of an input shaft yoke 11, an output shaft yoke 12, a pair of hemispherical resin balls 13, and a compression coil spring 14. The coil spring 14 is accommodated in a recess 13b of each resin ball 13 in such a condition as a certain amount compressed. At the time of assembly each resin ball 13 is repulsed by a specified pushing force and put in pressure contact with circular arc ends 11a, 12a of yokes 11, 12, and the side wall of a circular arc groove 13a of each resin ball 13, in which the circular arc ends 11a, 12a are fitted, is partially deformed elastically by means of wedge effect so that no rotational play due to dispersion in manufacture of the yokes 11, 12 will be generated in the fitting parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a universal joint used, for example, in a tilting connection shirt I portion of a tilt steering device in an automobile, and in particular, one end is connected to an input/output shaft, respectively. and an input/output shaft yoke whose other end is formed into an arc shape, and a cross-shaped arc groove on the outer periphery into which the input shaft yoke and the output shaft yoke are fitted facing each other, and the top part is used for assembly. A pair of cut-off hemispherical resin balls are assembled so that the hemispherical resin balls form a substantially spherical body between the two yokes, and the rotational torque applied to the input shaft is transferred between the two hemispherical resin balls. The present invention relates to a universal joint in which transmission is transmitted to an output shaft through a universal joint.

[Prior art]

This type of universal joint has conventionally been used, for example, in Japanese Utility Model Publication No. 591224
This is proposed in Publication No. 30. However, in this type of universal joint, the input shaft yoke and the output shaft yoke are generally forged products, and the variations between products are large, making it impossible to finish the resin balls with high precision. Therefore, the gaps necessary for good adhesive bonding and smooth operation may not be formed at the fitting parts of each yoke and each resin ball, resulting in poor assembly and operability, or larger gaps than necessary may be formed, resulting in large Rotational play may occur. For this reason, conventionally,
The gap noted in 2 is set to a value (relatively large value) required for good assembly and smooth operation, and the rotational play caused by this is interposed between both resin balls and is placed between each yoke at each tip. A means for absorbing this is adopted by means of O-shaped springs that directly press against each other and urge both yokes in opposite rotational directions.

It is also possible to achieve the optimal clearance value by finishing both yokes with high precision, but in order to do so, both yokes must be polished or both yokes must be manufactured by ultra-precision forging. Otherwise, the manufacturing cost 1- will be greatly increased.

[Problems to be Solved by the Invention] By the way, the above-mentioned O-shaped spring can be glued into the groove formed on the mating surface of each resin pole, that is, the groove that extends to the bottom of the adjacent arcuate groove. However, the torsional strength of the thinned portion due to such grooves is reduced, and there is a risk that a sharp crank may occur in this portion.

In addition, since the above-mentioned 0-shaped springs are in direct pressure contact with each yoke at each tip, the sliding between both yokes and both resin balls caused by the intersection angle of the input shaft and output shaft when transmitting rotation l and torque. There is a risk that the movement will be hindered, and there is also a risk that each yoke will wear unevenly, which may increase rotational play. Therefore, the operability and durability of the universal joint are impaired.

The present invention has been made to address the above-mentioned problems, and provides an inexpensive universal joint that provides sufficient torsional strength while reducing rotational play, and that can operate at the same temperature for a long period of time. It is intended to.

[Means to solve the problem]

In order to achieve the above object, in the universal joint of the present invention, the cross-sectional shape at the fitting portion of each yoke and each resin ball is made into a shape that can be simulated, and the mating surfaces of both the resin poles are A separating means for separating the resin balls was provided. In addition, to ensure smooth operation over a long period of time from assembly to long-term use, the depth of the arcuate groove of each resin ball has been gradually deepened from the mating surface side to the top side. .

[Action/effect of the invention]

In the universal joint according to the present invention, the separating means separates both resin balls and brings them into pressure contact with the arcuate ends of each yoke.

Therefore, the side walls of the arcuate grooves of each resin ball into which the arcuate ends of each yoke fit are partially elastically deformed due to the wedge action.
Rotational play that may occur at the fitting portion due to manufacturing variations between the two yokes is eliminated. Therefore, this effect can be obtained almost unchanged even when the resin balls are worn out due to sliding between both yokes and both resin balls. in this way,
In the universal joint, rotational play can be eliminated by using an inexpensive yoke manufactured by ordinary forging.

In addition, in the universal joint according to the present invention, the rotational play caused by manufacturing variations in both yokes is prevented by the action of the separation means provided on the mating surfaces of each resin ball, which is close to the connection center and does not have much effect on torsional strength. Since it is designed to disappear, it is possible to reduce rotational play and ensure sufficient torsional strength, and it is also possible to ensure smooth sliding between both yokes and both resin balls for a long period of time.

Furthermore, in the universal joint according to the present invention, when the depth of the arc groove of each resin ball is increased sequentially from the mating surface side to the top side, the wall thickness of the portion of the resin ball responsible for torque transmission (the mating surface side portion) By ensuring sufficient torsional strength, it is possible to prevent abnormal pressure contact (interference) between the bottom surface of the arcuate groove on the top side of the resin ball and the yoke when the resin ball is pressed against the yoke by the separation means. , Smooth operability can be ensured for a long period of time after assembly.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 shows a tilt steering device B for an automobile that employs a universal joint A according to the present invention, and as shown in FIGS. ．． Output shaft yoke 12° Pair of hemispherical resin balls 1
3 and a compression coil spring 14.

The input shaft yoke 11 is integrally connected (formed) to a steering upper shaft 22 to which a steering wheel 21 is assembled, and is formed by normal forging together with the shirt 1-22.

On the other hand, the output shaft yoke 12 is fitted and welded to the upper end of the steering shaft 123, and is formed by ordinary forging like the input shaft yoke 11.

Thus, the connecting end portions 11a, 1 of each yoke 11.12
2a, as shown in FIGS. 3 and 4, is formed in an arc shape centered on the connection center 01, and its cross-sectional shape has an approximately 40 degree opening as shown in FIG. It has a trapezoidal shape with an angle θ1, and the width at the reference circle SφA is 1.
．． 1, and the diameter of the inner circumference from the connection center 01 is R1 (see FIGS. 3 and 4). Note that the yoke 12 is formed with a U-shaped notch 12b for assembly.

Each resin ball 13 has a bending elastic modulus of approximately 25,500 to 26,500 k in order to obtain a predetermined torsional strength and desired elastic deformation.
g/- material, for example, polyacetal resin, a copolymer made of polyplastic EL sold under the trade name Duracon M25, and are formed in the same shape, and on the outer periphery are the arc-shaped ends za of both yokes 11 and 12, A cross-shaped arcuate groove 13a is formed in which the grooves 12a are fitted facing each other, and the top portion is cut off for the assembly. Note that both yokes 11. , 12 arcuate ends 1
A pair of notches 13a1 are provided for assembling the arcuate grooves 13a of the resin ball 13 with the grooves 1a, 12;i so as to eliminate rotational play.

Therefore, the arcuate groove 133 of each resin ball 13 has a trapezoidal shape with an opening angle θ2 of approximately 39 degrees, as shown in FIGS. 6 and 7, and is aligned with the reference circle SφA. The width of the yoke is L2 (the arc-shaped end 11a of each yoke 11゜12).
, 12a (slightly larger than Ill I-1 of 12a), and as shown in FIG. The groove has an arcuate shape (slightly smaller than the inner circumferential diameter R1 of the arcuate end Lla, 12a), and the depth h of the groove gradually increases from the mating surface side to the top side. Further, a circular recess 13b for accommodating the compression coil spring 14 is formed in the center of the mating surface of each resin ball 13, as shown in FIGS. 7 to 9.

The compression coil spring 14 is compressed by a predetermined amount and accommodated in the recess 13b of each resin ball 13, and when assembled, each resin ball 13 is compressed with a predetermined pressing force (approximately 6
0 to 80 kg/cn+) and separate each yoke 11.
The arcuate groove 1 of each resin ball 13 is brought into pressure contact with the arcuate end portion 11a12a of the resin ball 12, and into which the arcuate end portions 11a and 12a fit.
The side wall of yoke 3a is partially elastically deformed by a wedge action to prevent rotational play from occurring in the fitting portion due to manufacturing variations in both yokes 11 and 12. Note that this spring 14
The above pressing force of the arcuate end 11 of each yoke 11.12
a, 12a, the material of each resin ball 13, the shape of the arcuate groove 13a, etc., and if it is less than the upper limit of the optimum range, the distance between each yoke 11, 12 and each resin ball 13 If the sliding resistance increases rapidly and becomes below the lower limit of the optimal range, the rotational play between each yoke 11, 12 and each resin ball 13 will increase rapidly, so the optimal range is set taking these into consideration. .

By the way, the above-mentioned universal joint A is constructed by (1) combining a pair of resin balls 13 and a spring 14, and connecting the yoke 12 so that the top of each resin ball 13 coincides with the tip of the arcuate end 12a of the yoke 12; It fits into the arcuate end 12a. ■The pair of resin balls 13 and spring 14 fitted with the arc-shaped end 12a of the yoke 12 are rotated approximately 90 degrees, and the top of one resin ball 13 and the notch 1 of the yoke 12 are rotated approximately 90 degrees.
Match 2b. ■Top of resin ball 13 and twist 12
The resin ball 13 and the arcuate end 11a of the yoke 11 are fitted together by aligning the tip of the arcuate end 11a of the yoke 11 with the space formed between the notches 12b. It can be assembled in the following steps.

In the universal joint A assembled in this way, the spring 14 separates both resin balls 13 and brings them into pressure contact with the arcuate ends 11a12a of each cork 11.12. Therefore, the side walls of the arcuate grooves 133 of each resin ball 13 into which the arcuate ends 11a and 12a of each yoke are fitted are partially elastically deformed due to the wedge action, and the yokes 1112 that may be formed in the fitting portion are partially elastically deformed. Rotational play due to manufacturing variations disappears.

Therefore, this effect can be obtained almost unchanged even if the resin ball 13 is worn out due to sliding between the yokes 11, 12 and the resin poles 13. in this way,
In the universal joint, inexpensive yokes 11 and 12 manufactured by ordinary forging can be used to eliminate rotational play.

Note that in this embodiment, the arcuate end portion 11 of each yoke
Since the opening angle θ1 of the arcuate grooves 13a and 12a of each resin ball 13 is approximately 40 degrees, and the opening angle θ2 of the arcuate groove 13a of each resin ball 13 is approximately 39 degrees, the wedge action described above can be effectively obtained, and the bending elasticity The rate is approximately 25,500 to 26,500 kg/
Since each resin ball 13 is formed of the cJ material, the above-mentioned elastic deformation due to the wedge action can be properly obtained, and the rotational backlash mentioned above can be reliably eliminated.

In addition, in the above-mentioned universal joint A, a recess 13b is provided in the center of the mating surface of each resin ball 13, which is close to the connection center 01 and does not have much effect on torsional strength, and the spring 14 provided in this recess 13b is Since the pressing force is used to eliminate the rotational play caused by manufacturing variations in the two yokes 11 and 12 as described above, it is possible to reduce the rotational play and ensure sufficient torsional strength, and the two yokes 11 and 12 are
1.12 and both resin balls 13 can be ensured for a long period of time.

Furthermore, in the above-mentioned universal joint, since the depth h of the arcuate groove 13a of each resin ball 13 is deepened sequentially from the mating surface side to the top side, the portion of the resin ball 13 responsible for torque transmission (the mating surface side portion ) with sufficient wall thickness to ensure sufficient torsional strength, the resin ball 1 is attached by the spring 14.
When pressing the yokes 11 and 12 of No. 3, the resin balls 1
It is possible to prevent abnormal pressure contact (interference) between the bottom surface of the top side circular groove 13a of No. 3 and the yoke 11.12, and smooth operability can be ensured for a long period of time after assembly.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a tilt-steering device for an automobile employing a universal joint according to the present invention, and FIG.
An enlarged view of the universal joint shown in the figure, Figure 3 is an exploded view of the same, Figure 4
The figure is a side view of the left yoke shown in Figure 3, Figure 5 is a cutaway end view of the arcuate end of each yoke, and Figure 6 is a side view of the left yoke shown in Figure 3.
Figure 7 is a front view of the single resin ball seen from the top side shown in Figures and Figure 3, Figure 7 is a rear view of the single resin ball seen from the mating surface side, and Figure 8 is along the line ■-■ in Figure 7. Cross section, No. 9
The figure is a sectional view taken along line IX-IX in FIG. 6. Explanation of symbols 11... Input shaft yoke, 1], a... Arc-shaped end, 12... Output shaft yoke, 12a... Arc-shaped end, 13... Resin ball, 13a...・Circular groove, h...
- Depth of circular arc groove, 13b... Recess, 14... Compression coil spring (separation means), A... Universal joint, 21
...shirt [-(input shaft), 23...shaft (output shaft). Applicant Toyota Motor Corporation-1 (Company

Claims (2)

[Claims] (1) An input/output shaft yoke whose one end is connected to the input/output shaft and whose other end is formed into a circular arc shape, and a cross-shaped circular arc on the outer periphery of which the input shaft yoke and the output shaft yoke are fitted facing each other. A pair of hemispherical resin balls with grooves and their tops cut off for assembly are assembled so that both hemispherical resin balls form a substantially spherical body between the two yokes. In the universal joint that transmits rotational torque applied to the shaft to the output shaft via the resin balls, the cross-sectional shape at the fitting portion of each yoke and each resin ball is shaped to provide a wedge effect, A universal joint characterized in that a separating means for separating both the resin balls is provided on a mating surface of the resin balls. (2) The universal joint according to claim (1), wherein the depth of the arcuate groove of each resin ball is gradually increased from the mating surface side to the top side.