JPH0247769Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a universal joint, and particularly to a universal joint suitable for connecting an input shaft and an output shaft of a vehicle steering mechanism or the like.

[Prior art]

Universal joints are used in vehicle steering mechanisms and the like because they can smoothly transmit rotational torque from an input shaft to an output shaft.

Conventional universal joints of this type include an input/output shaft yoke whose one end is connected to the input shaft or the output shaft, and the other end is formed into a U-shape, as shown in a and b in Fig. 1. 10 and a sphere 14 formed around the outer periphery with two trapezoidal grooves 12 that are orthogonal at two points on the outer periphery and into which an input shaft yoke and an output shaft yoke can be fitted facing each other. A system has been proposed in which the rotational torque of the shaft is transmitted to the output shaft via the sphere 14.

The sphere 14 shown in FIG. 1b is shown in FIGS.
It is obtained by placing two hemispheres back to back as shown in FIG. It is shaped like a cross. A universal joint is formed by fitting the U-shaped head 18 of the input/output shaft yoke 10 into this trapezoidal groove 12. Note that a in FIG. 2 is a front view of the sphere 14;
Figure b is a cross-sectional view of the sphere 14 shown in figure a taken along the line A-A, and figure c is a rear view of the sphere 14 shown in figure a.

As described above, this type of universal joint is used as a universal joint by forming a trapezoidal groove 12 in the sphere 14 and fitting the U-shaped head 18 of the input/output shaft yoke 10 into this trapezoidal groove 12. .

Furthermore, in recent years, as parts have become lighter, it has been proposed that the sphere 14 be made of resin.

However, if the sphere is simply made of resin, holes will be formed in the thick parts during molding of the sphere, resulting in a decrease in strength. Therefore, it has been proposed to use glass fiber as a reinforcing material and to form a sphere by mixing glass fiber with resin. However, with this configuration, the glass fibers come into contact with the yoke, causing wear on the surface of the yoke, and the movement between the yoke and the sphere may lack smoothness. Compared to the yoke structure,
There is a problem in that the vibration reduction effect due to the viscoelastic properties of the resin is also inferior.

An object of the present invention is to provide a universal joint that can prevent a decrease in strength due to defects caused by molding that are observed in conventional resin ball joints.

[Means to solve the problem]

In order to achieve the above object, the present invention has one end connected to an input/output shaft, and the other end connected to an input/output shaft, respectively.
It includes an input/output shaft yoke consisting of a head shaped like a letter, and a pair of resin hemispheres having grooves formed on their outer peripheral surfaces that can fit into the substantially U-shaped head of the input/output shaft yoke. , the back sides of each hemisphere are fitted together to form a sphere, and each approximately U-shaped head of the input/output shaft yoke faces each other in the groove of each hemisphere, and one head is opposed to the other head. In a universal joint formed by fitting with the two hemispheres rotated approximately 90 degrees, from this hemisphere, from the back side of the hemisphere to approximately the center of the thick part between the grooves of each hemisphere, It consists of a universal joint with a highly hard core material inserted.

[Effect]

An input shaft and an output shaft are connected to the input shaft yoke and the output shaft yoke, respectively, and when rotational torque is transmitted from the input shaft to the input shaft yoke, the input shaft yoke rotates according to this rotational torque. As a result, the rotational torque accompanying the rotation of the input shaft yoke is transmitted to the output shaft via the sphere and the output shaft yoke. At this time, twisting of the sphere due to rotation of the input shaft yoke and the output shaft yoke is suppressed by the core material of each hemisphere, and rotational torque from the input shaft to the output shaft is smoothly transmitted. In addition, a core material is inserted into each hemisphere, and the wall thickness of each hemisphere is approximately uniform, which prevents defects from occurring during molding of each hemisphere. This prevents a decrease in strength.

[Embodiments of the invention] Hereinafter, preferred embodiments of the invention will be described based on the drawings.

FIG. 3 shows the configuration of an embodiment suitable for use in a tilt type or manual type steering mechanism.

In FIG. 3, the input shaft yoke 30 and the output shaft yoke 31 are composed of a connecting portion 32 connected to the input shaft or the output shaft, and a head portion 34 formed in a U-shape. Fits into the input/output shaft yokes 30, 31,
The sphere 36 for transmitting rotational torque from the input shaft to the output shaft has two grooves 38 orthogonal to each other at two points on the outer periphery, into which the input shaft yoke 30 and the output shaft yoke 31 can be fitted facing each other. It is formed around the outer periphery.

Here, since the present invention aims to improve torsional strength, in this embodiment,
The fitting portions 40 of the input/output shaft yokes 30, 31 with the spheres 36 are formed in an arc shape, and the grooves 38 of the spheres 36 are also formed in an arc shape. Note that the groove width of the groove 38 is formed to be slightly narrower than that of the conventional trapezoidal groove 12.

The sphere 36 shown in Fig. 3b is obtained by placing two resin hemispheres shown in Fig. 4 a, b, and c back to back. When joining these two hemispheres, a spring is fitted into the recess 42 on the back of one hemisphere, and the backs of the other hemisphere are brought together to form the sphere 3 shown in FIG.
You can get 6.

Further, in this embodiment, a concave protrusion 44 is formed on the back surface of the sphere 36, and this concave protrusion 44
A glass-filled molded insert 46 made of a material different from that of the sphere 36 is inserted during or after injection molding. By inserting the nest 46 into the thick part between the grooves 38 of the sphere 36 from the back side of the hemisphere to almost the center of the thick part, it is possible to prevent internal defects from occurring during injection molding. .

When fitting the input/output shaft yokes 30 and 31 into the sphere 36, as shown in FIG. Fold 90 degrees 2
If the input shaft yoke is placed in the position shown by the dotted chain line, the input shaft yoke will not come out of the groove 38. Next, as shown in FIG. 6, the output shaft yoke 31 connected to the output shaft is
Insert into the side of the sphere 36 without the groove 38, and connect the input shaft 48.
By tilting it 90 degrees in the opposite direction to the position shown by the two-dot chain line, it will not come out of the groove 38. FIG. 7 shows a state in which the input shaft 30 and the output shaft 31 are attached to the sphere 36.

Further, in this embodiment, a structure as shown in FIG. 8 is adopted in order to prevent the occurrence of play in the fitting portion. FIG. 8 shows the C of the sphere 36 in FIG.
- A cross-sectional view taken along line C, showing the recess 42.
A spring 50 is inserted therein. The open end of the spring 50 as shown in FIG. 10 applies a predetermined biasing force to the fitted input shaft yoke 30 and output shaft yoke 31 to prevent rattling.

Here, static torsional strength tests were conducted on the conventional product and the universal joint according to the present invention at a joint angle of 15 degrees, and the test results shown in a, b, and c in Figure 9 were obtained. .

In Fig. 9, a shows the test results for the conventional product, b shows the test results when no nest is inserted into the universal joint of the present invention, and c shows the test result of the universal joint of the present invention in which the nest is inserted into the sphere. These are the test results.

From the test results shown in Figure 9, the torsional strength of the universal joint c according to the present invention was improved by more than 45% compared to the conventional joint shown in a, and the torsional strength was improved by more than 17% than that shown in b. This was confirmed. As described above, the universal joint of this embodiment can improve the torsional strength compared to the conventional joint, and therefore can also improve the plastic deformation and breaking strength compared to the conventional joint.

[Effect of idea]

As explained above, according to the present invention, since a core material is inserted into each resin hemisphere, it is possible to prevent a decrease in strength due to defects in the molding of each hemisphere, and to prevent twisting. This can contribute to improving strength.

[Brief explanation of the drawing]

a, b in FIG. 1 are perspective views of a conventional universal joint, a, b, c in FIG. Figures 3a and 3b are perspective views showing one embodiment of the present invention;
Figures a, b, and c are front views of the sphere shown in Figure 3, and B
- A cross-sectional view and a rear view taken along line B, FIG. 5 is an explanatory diagram of assembly when an input shaft yoke is attached to a sphere according to the present invention, and FIG. 6 is an illustration of an output shaft yoke attached to a sphere according to the present invention. Figure 7 is a front view of the universal joint according to the present invention, Figure 8 is a sectional view of the connecting surface of the sphere according to the present invention, and Figures a, b, and c in Figure 9 are the conventional universal joint. FIG. 10 is a side view of the spring. 30... Input shaft yoke, 31... Output shaft yoke, 36... Sphere, 38... Arc-shaped groove, 44...
Concave protrusion, 46... nest, 50... spring.

Claims (1)

[Claims for Utility Model Registration] An input/output shaft yoke consisting of a head whose one end is connected to an input/output shaft and whose other end is approximately U-shaped, and the input/output shaft yoke is approximately U-shaped. It is equipped with a pair of resin hemispheres with grooves formed on the outer circumferential surface that can be fitted into the head, and the back sides of each hemisphere are fitted together to form a sphere, and the input/output shaft yoke is connected to the groove of each hemisphere. In a universal joint in which substantially U-shaped heads face each other and are fitted with one head rotated by approximately 90 degrees, the grooves of each hemisphere are fitted. A universal joint characterized in that a core material having a higher hardness than that of the hemisphere is inserted from the back side of the hemisphere within the thick part to approximately the center of the thick part.