Synchronizer ring for a synchronization unit of a manual transmission and method for the production thereof

Abstract

A synchronizer ring for a synchronization unit of a manual transmission is produced from a sheet metal material and has a conical friction surface on the inner side thereof and has a device for radial centering of the synchronizer ring on the outer side thereof. The device for radial centering includes a plurality of separate arc-shaped centering collar portions spaced apart from one another in the circumferential direction.

Claims

1. A synchronizer ring for a synchronization unit of a manual transmission, the synchronizer ring comprising: sheet metal material having an inner side with a conical friction surface and an outer side, said sheet metal material having a radial collar; and means for radial centering of the synchronizer ring disposed on said outer side of said sheet metal material, said means for radial centering having a plurality of separate arc-shaped centering collar portions spaced apart from one another in a circumferential direction of said sheet metal material, said arc-shaped centering collar portions extending from said radial collar in a direction of an axially opposite end and, from there, back in a direction of said radial collar.

2. The synchronizer ring according to claim 1, wherein said arc-shaped centering collar portions are produced from said sheet metal material by forming.

3. The synchronizer ring according to claim 1, wherein said arc-shaped centering collar portions have outer surfaces lying on said outer side of said sheet metal material and said outer side being a cylindrical surface, a diameter of which corresponds to a centering diameter.

4. The synchronizer ring according to claim 3, wherein said arc-shaped centering collar portions are symmetrical with respect to a plane extending through a longitudinal axis of said sheet metal material.

5. The synchronizer ring according to claim 1, wherein said arc-shaped centering collar portions include three to six said arc-shaped centering collar portions distributed over a circumference of said sheet metal material.

6. A method for producing a synchronizer ring for a synchronization unit of a manual transmission, which comprises the steps of: providing a sheet metal material having an inner side with a conical friction surface and an outer side with means for radial centering of the synchronizer ring, the sheet metal material further having a radial collar; and producing a plurality of separate arc-shaped centering collar portions spaced apart from one another in a circumferential direction as the means for radial centering, the arc-shaped centering collar portions extending from the radial collar in a direction of an axially opposite end and, from there, back in a direction of the radial collar.

7. The method according to claim 6, which further comprises forming a material flow on the outer side of the sheet metal material into a ring and this is brought about in axial and radial directions by means of a forming tool in order to produce the arc-shaped centering collar portions.

8. The method according to claim 7, which further comprises providing a stamping punch as the forming tool.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a diagrammatic, perspective view of a first illustrative embodiment of a synchronizer ring according to the invention;

(2) FIG. 2 is an enlarged, perspective view of a detail of the synchronizer ring shown in FIG. 1;

(3) FIG. 3 is a plan view of the synchronizer ring shown in FIG. 1;

(4) FIG. 4 is a plan view of a detail of the synchronizer ring shown in FIG. 1 in the region of a centering collar portion;

(5) FIG. 5 is a sectional view taken along the line V-V shown in FIG. 4;

(6) FIG. 6 is a sectional view taken along the line VI-VI shown in FIG. 4;

(7) FIG. 7 is a sectional view taken along the line VII-VII shown in FIG. 4; and

(8) FIG. 8 is a perspective and sectional view of a detail of the synchronizer ring according to the invention according to a second illustrative embodiment.

DETAILED DESCRIPTION OF THE INVENTION

(9) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a perspective view of a synchronizer ring 1 for a synchronization unit of a manual transmission. FIG. 2 shows a detail of the synchronizer ring 1 in an enlarged view. The synchronizer ring 1 is produced from a sheet metal material. For the sake of simplicity, certain functional elements are not illustrated in FIG. 1. These are blocking teeth, which extend radially outwards, and indexing or centering tabs, which extend in the axial direction on the outer side of the synchronizer ring 1, and coupling tabs or coupling elements, which extend radially inwards.

(10) The synchronizer ring 1 has a conical friction surface 2 on the inner side thereof. Means for radial centering are provided on the outer side thereof. In this illustrative embodiment, the means contain a plurality of separate arc-shaped centering collar portions 3 spaced apart from one another in the circumferential direction. Just one single centering collar portion 3 is illustrated in FIG. 1.

(11) FIG. 3 is a plan view of the synchronizer ring 1, in which it can be seen that the ring has a total of three arc-shaped centering collar portions 3, 4, 5 spaced apart in the circumferential direction (tangential direction). The centering collar portions 3, 4, 5 are distributed at equal distances in the circumferential direction.

(12) The synchronizer ring 1 is produced from a sheet metal material. First of all, a ring is produced, which is formed by a stamping punch, which is moved in the axial direction. A material flow in the direction of the blocking teeth is thereby produced. The material flow takes place both in the axial direction and in the radial direction. The undulating shape of the centering collar portions 3, 4, 5 which is illustrated in the enlarged view in FIG. 2 can be achieved in this way with relatively few forming stages. Tests have shown that the centering collar portions 3, 4, 5 have the required strength, even under dynamic loads.

(13) It can be seen in FIG. 2 that the arc-shaped centering collar portion 3 extends from a collar 6, which extends radially outwards and which has the blocking teeth (not shown), in the direction of the axially opposite end 7 of the synchronizer ring 1. From there, the centering collar portion 3 extends back in the direction of the collar 6. It can be seen from FIG. 2 that the centering collar portion 3 is symmetrical with respect to a plane which extends through the longitudinal axis of an (imaginary) cylinder, wherein the centering collar portions lie on the cylindrical surface.

(14) FIG. 2 illustrates the resulting centering surface 8, which extends axially and tangentially. The centering surface is a component part of the abovementioned cylindrical surface. The radial centering of the synchronizer ring 1 is brought about by this centering surface 8. The centering surface 8 is curved in the tangential direction. In this illustrative embodiment, it has an irregular circumferential line. In contrast to a conventional centering tab produced by bending, the centering surface 8 has a larger area, and therefore contact forces are distributed in the axial direction and in the tangential direction. The large centering surface 8 with material attachment over a large cross section prevents premature failure of the material, especially under dynamic loading.

(15) FIG. 4 is a plan view of the synchronizer ring 1 in the region of the centering collar portion 3. FIG. 4 illustrates the axial end 7 of the synchronizer ring 1, the centering collar portion 3 and the collar 6.

(16) FIG. 5 is a sectioned view and shows a section along the line V-V in FIG. 4. It can be seen in FIG. 5 that the centering surface 8 has been produced by the forming process. The position of the centering surface 8 rises in the direction of view.

(17) FIG. 6 is a sectioned view similar to FIG. 5 and shows a section along the line VI-VI in FIG. 4. In comparison with FIG. 5, it can be seen that the centering surface 8 is wider in the axial direction.

(18) FIG. 7 is a similar illustration and shows a sectioned view along the line VII-VII in FIG. 4. At this position, the centering surface 8 is narrower in comparison with FIG. 6. The shape and size of the centering surface 8 can be influenced through the choice of a suitable pressing tool.

(19) FIG. 8 is a sectioned view of a detail of a second illustrative embodiment of a synchronizer ring. A synchronizer ring 9 has fundamentally the same structure as synchronizer ring 1. For the sake of simplicity, conventional component parts, such as the blocking teeth and coupling and indexing tabs, are not illustrated in the case of synchronizer ring 9 either.

(20) Like the first illustrative embodiment, synchronizer ring 9 has the radially extending collar 6, a conical friction surface 2 formed on the inner side thereof, and an axial end 7. A centering collar portion 10 having a centering surface 11 is produced by forming. In FIG. 8, it can be seen that the centering collar portion 10 has been produced by a material flow on the outer side 12 of the synchronizer ring 9.

(21) Starting from the collar 6, the arc-shaped centering surface 11 extends axially and in a tangentially oblique way in the direction of the axial end 7 of synchronizer ring 9. From a certain point, the slope decreases, and the centering collar portion 10 extends predominantly in a tangential direction. The section plane 13 shown in FIG. 8 is simultaneously the plane of symmetry of the centering collar portion 10 and of the centering surface 11. Thus, one half of the centering collar portion 10 is illustrated in FIG. 8.

(22) The synchronizer rings described in the illustrative embodiments have the advantage that the centering collar portions can be produced in a relatively simple manner with a small number of forming steps. The synchronizer rings have a sufficient strength under dynamic load in the region of the centering collar portions thereof. In comparison with conventional centering devices, the centering collar portions are widened both in the axial direction and in the radial direction. The centering collar portions described have no effect on other functional elements. In particular, the centering collar portions do not lead to a reduction of blocking teeth.

(23) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 1 synchronizer ring 2 friction surface 3 centering collar portion 4 centering collar portion 5 centering collar portion 6 collar 7 axial end 8 centering surface 9 synchronizer ring 10 centering collar portion 11 centering surface 12 outer side 13 section plane