JP2880379B2 - Molds for forming continuously variable speed pulleys - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for forming a continuously variable speed pulley.

[0002]

2. Description of the Related Art A pair of pulley half-shells having opposing surfaces formed as shallow conical surfaces are attached so as to be spaced apart from each other, and the transmission radius is changed by changing the suspension radius of a V-belt stretched between them. In a continuously variable transmission in which the rotation speed and the rotation torque to be changed are variable, generally, a configuration is adopted in which one movable pulley half-shell is mounted on a spline shaft so as to be non-rotatable and slidable in the axial direction. Has been adopted.

For this reason, in this kind of movable pulley half-shell, a large number of grooves corresponding to the ridges of the spline shaft must be formed in the shaft hole, and smooth sliding is ensured. For this reason, when forming the groove, precise processing such as broaching and grinding is required, and there is a problem that the manufacturing cost is significantly increased.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem.
It is an object of the present invention to provide a new mold for forming a new continuously variable speed pulley that can be easily formed and operates smoothly.

[0005]

That is, the present invention provides a mold for forming a half-shell of a movable pulley for continuously variable transmission in order to achieve the above object. At the center of the mold, a columnar punch provided with several ridges for forming ball grooves extending in the axial direction on the peripheral surface is erected, and opposed to the lower mold, a shallow movable pulley half shell is provided. An upper die forming a conical facing surface is arranged so as to be capable of being separated and joined.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows an example of a continuously variable speed pulley formed by a molding die according to the present invention. The pulley for continuously variable transmission shown in this figure is constituted by a fixed pulley half-shell 1 and a movable pulley half-shell 4, and the fixed pulley half-shell 1 is integrally fixed to a shaft 12 with screws 3; The movable pulley half-shell 4 is slidably mounted on the shaft 12, and by changing the distance between the two shafts, the movable pulley half-shell 4 frictionally contacts the shallow conical surfaces 2, 6 formed on these opposing surfaces. The rotation speed and the rotation torque to be transmitted can be changed by changing the winding radius of the suspended V-belt 17.

The movable pulley half-shell 4 constituting the continuously variable transmission pulley includes a pulley portion 5 and a boss portion 7.
And a shaft hole 8 formed in the center portion.
, Extending from the boss portion 7 directly below the pulley portion 5
The ball grooves 9 # are formed in parallel with the axis at an interval of 120 °, and the ball grooves 9 # are formed between the ball grooves 9 # and the ball grooves 13 # on the shaft 12 formed so as to face each other. Is mounted so as to be non-rotatable and slidable in the axial direction via a ball 14 interposed therebetween. Reference numeral 15 in the drawing indicates a spring that constantly biases the movable pulley half-shell 4 in the direction of the fixed pulley half-shell 1.

FIG. 3 shows a mold according to an embodiment of the present invention for forming the movable pulley half-shell 4 described above.

In the figure, reference numeral 20 denotes a punch standing upright on a backing plate 22. This punch 20 has a cylindrical shape so as to form a shaft hole 8 in the shaft center of the movable pulley half-shell body 4. A boss 7 is formed on the surface of the shaft hole 8.
The protrusions 21 # for recessing the three ball grooves 9 # are formed in the axial direction so as to extend 120 degrees from the pulley portion 5 to the pulley portion 5.

On the other hand, reference numerals 25 and 30 in the figure denote a lower die and an upper die which are arranged to face each other to form the outer portion of the movable pulley half-shell 4, and the lower die supported by the cushion rod 26. 25 has a cavity for forming the back surface of the pulley portion 5 of the movable pulley half-shell 4 and the boss 7, and the boss forming recess 27 of the lower die 25 has an outer surface corresponding to the ball groove 9. Three concave grooves 28 for forming the ridge 10 are formed in the axial direction, and a surface 31 forming the conical surface 6 of the movable pulley half-shell 4 is provided on the opposing surface of the upper die 30. Are formed.

In the embodiment constructed as described above, the pulley portion 5 and the boss portion 7 are subjected to a hot forging step in advance.
When the movable pulley half-shell 4 roughly formed with the shaft hole 8 is subjected to an annealing step to remove the thermal strain, and then sent to the cold forging department, the movable pulley half-shell 4 becomes as described above. Molding corresponding to the mold is performed between the mold 1 and the lower mold 4, and three ball grooves 9 に are formed on the inner peripheral surface of the shaft hole 8 so as to improve the molding accuracy of the mold like other parts. Densely molded with appropriate accuracy.

Therefore, the movable pulley half-shell 4 formed in this manner is fitted to the shaft 12 so as to face the fixed pulley half-shell 1, and the movable pulley half-shell 4
When the ball 14 is closely fitted between the ball grooves 9 and 13 formed on the inner peripheral surface of the shaft hole and the outer peripheral surface of the shaft 13, the movable pulley half-shell 4 does not rattle in the rotation direction. In addition, the pulley is configured as a continuously variable pulley that can slide smoothly in the axial direction.

In the embodiment described above, three ball grooves 9 are provided in the shaft hole 8. However, in order to further reduce the load acting on the pulley and the play in the rotation direction, The number of these ball grooves 9 can be further increased.

[0014]

As described above, according to the present invention, when forming a movable pulley half-shell body of a continuously variable transmission, a circle having a ridge for forming a ball groove formed on a peripheral surface at the center of a mold. A pillar-shaped punch is erected, and the outer shape of the pulley is formed based on this punch. At the same time, a ball groove is formed in the shaft hole of the movable pulley half-shell body, so that the formation of a grooved shaft hole is extremely easy. Not only can it be obtained, but also depending on the accuracy of the ridge formed on the outer peripheral surface of the punch, the ball groove can be accurately and densely formed without the necessity of subsequent precision finishing.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a continuously variable speed pulley formed by a molding die according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a cross-sectional view showing an embodiment of the present invention for a movable pulley half-shell molding die.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fixed pulley half-shell 4 movable pulley half-shell 5 pulley 7 boss 9 ball groove 12 shaft 13 ball groove 14 ball 20 punch 21 ridge for forming ball groove 25 lower die 30 upper die

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 55 / 36,55 / 56,9 / 12 B21K 1/42

Claims (1)

(57) [Claims] 1. A mold for molding a movable pulley half-shell for continuously variable transmission opposed to a fixed pulley half-shell, wherein a back surface of a pulley portion of the movable pulley half-shell and a boss are formed. At the center of the lower mold, a columnar punch provided with several ball groove forming protrusions extending in the axial direction on the peripheral surface is erected, and the movable pulley half-shell body is opposed to the lower mold. A molding die for a continuously variable transmission pulley, wherein an upper die forming a conical facing surface having a shallow width is disposed so as to be capable of being separated and joined.