METHOD FOR PRODUCING A SYNCHRONIZER RING AND ASSOCIATED SYNCHRONIZER RING

Abstract

A method produces a synchronizer ring for a synchronizing device in which blocking teeth extending radially outwards or radially inwards are produced by a forging method. The blocking teeth each have a flank portion and two oblique top flanks merging into a common top ridge. A depression is formed on the rear side of a blocking tooth opposite the top ridge.

Claims

1. A method for producing a synchronizer ring for a synchronizing device, which comprises the steps of: producing blocking teeth extending radially outwards or inwards by a forging method, the blocking teeth each having a flank portion and two oblique top flanks merging into a common top ridge; and forming a depression on a rear side of a blocking tooth opposite the common top ridge.

2. The method according to claim 1, which further comprises stamping an at least approximately hemi-spherical or spherical cup-shaped depression as the depression in the blocking tooth.

3. The method according to claim 1, which further comprises stamping the depression as a drop-shaped depression in the blocking tooth and the drop-shaped depression is spherically shaped at a first end and pointed in shape at a second end, wherein the pointed in shape end is oriented radially inwards.

4. The method according to claim 1, which further comprises stamping the depression as a drop-shaped depression in the blocking tooth, the drop-shaped depression is spherically shaped at a first end and pointed in shape at a second end, wherein the pointed in shape end is oriented radially outwards.

5. The method according to claim 1, which further comprises stamping the depression in the blocking tooth, an axial extent of the depression increases radially towards an end of the blocking tooth.

6. The method according to claim 1, which further comprises stamping the depression in the blocking tooth and the depression is configured as a groove extending in a radial direction.

7. The method according to claim 6, wherein a depth of the groove increases radially towards an end of the blocking tooth.

8. The method according to claim 1, which further comprises producing the synchronizer ring from a metal sheet having a thickness in a range of 1.5 mm to 3.0 mm.

9. The method according to claim 1, which further comprises producing the synchronizer ring from a metal sheet having a thickness in a range of 1.6 mm to 1.9 mm.

10. A synchronizer ring for a synchronizing device, comprising: blocking teeth produced by a forging method and extend radially outwards or inwards and each of said blocking teeth having a flank portion and two oblique top flanks merging into a common top ridge; and a blocking tooth of said blocking teeth having a rear side with a depression formed therein opposite at least one of said oblique top flanks.

11. The synchronizer ring according to claim 10, wherein said depression is selected from the group consisting of: a depression configured at least generally as a hemisphere or spherical cup; a drop-shaped depression being spherically shaped at a first end and pointed in shape at a second end, wherein said pointed in shape end is oriented either radially inwards or radially outwards; a depression having an axial extent which increases radially outwards; and a depression configured as a groove extending in a radial direction, wherein a depth of said groove increases radially towards an end of said blocking tooth.

12. The synchronizer ring according to claim 10, wherein said depression has a maximum depth of 0.3 mm to 1.2 mm.

13. The synchronizer ring according to claim 10, wherein said depression has a maximum depth of about 0.6 mm.

14. The synchronizer ring according to claim 10, wherein the synchronizer ring is produced from metal sheet having a thickness in a range of 1.5 mm to 3.0 mm.

15. The synchronizer ring according to claim 14, wherein the range of the thickness is 1.6 mm to 1.9 mm.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0028] FIG. 1 is a diagrammatic, perspective view of a section of a synchronizer ring produced by the method according to the invention;

[0029] FIG. 2 is an enlarged, perspective view of a blocking tooth of the synchronizer ring in FIG. 1;

[0030] FIG. 3 is a plan view of a section of the synchronizer ring in FIG. 1;

[0031] FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

[0032] FIG. 5 is a sectional view similar to FIG. 4 with a depression of different design;

[0033] FIG. 6 is a sectional view of another illustrative embodiment of the depression;

[0034] FIG. 7 is another illustrative embodiment of the depression;

[0035] FIG. 8 is another illustrative embodiment of the depression; and

[0036] FIG. 9 is another illustrative embodiment of the depression.

DETAILED DESCRIPTION OF THE INVENTION

[0037] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a section of a synchronizer ring 1 which is produced by a forging method, in the course of which blocking teeth 2 extending radially outwards or radially inwards are formed. The synchronizer ring 1 has a plurality of index tabs 3, which are distributed over the circumference, and recesses 4. A collar 6 extending in the radial direction adjoins an annular surface 5 extending in the axial direction. The collar 6 has the blocking teeth 2 spaced apart from each other in the circumferential direction. In the enlarged view in FIG. 2, it can be seen that the blocking tooth 2 has a flank portion 7, adjoining which are two oblique top flanks 8, 9, which slope relative to one another and merge into a top ridge 10. The top ridge 10 is a flat surface (depending on the width; a flat surface if there is sufficient width), which is preferably situated in the plane defined by the collar 6.

[0038] In the illustrative embodiment shown, the synchronizer ring 1 is produced by cold forging a steel sheet, which is initially bent into a round blank and punched and pressed in several steps. The top ridge 10 shown in FIG. 2 is unwanted or the aim is to produce a top ridge with the minimum possible width, giving rise to a sharp edge between the two top flanks 8, 9. In order to ensure that as great as possible die filling is achieved in the region of the top ridge during the forming process, a depression is stamped in a rear side 11 of the blocking tooth 2, the side opposite the top ridge 10.

[0039] FIG. 3 shows the synchronizer ring 1 with the blocking teeth 2, the mutually opposite top flanks 8, 9 and the top ridge 10 in a plan view.

[0040] FIG. 4 is a sectioned view along the line IV-IV in FIG. 3. In FIG. 4, it can be seen that a depression 12 is stamped in the rear side 11 of the blocking tooth 2, the side being opposite the top ridge 10. In the illustrative embodiment shown, the depression 12 is of at least approximately spherical cup-shaped design. The step of stamping the depressions 12 can be carried out before the step of stamping the top flanks 8, 9. However, it is also possible to produce the depression 12 and the top flanks 8, 9 simultaneously or even subsequently in a final stamping or forming step.

[0041] The stamped depression 12 brings about a material flow towards the top ridge 10 during the forming process, as a result of which the height of the top formed by the top flanks 8, 9 and the top ridge 10 reaches the required level.

[0042] In contrast, conventional synchronizer rings have a solid blocking tooth. Reducing the sheet metal thickness used to produce the synchronizer ring to below a certain value is not possible with a conventional method since otherwise the required height of the blocking teeth cannot be achieved.

[0043] According to the method described, the depression 12 formed in the rear side 11 of the blocking tooth 2 brings about improved die filling in the region of the top ridge 10, with the result that the ridge has a minimum width.

[0044] In the illustrative embodiment shown, the synchronizer ring 1 is produced from steel sheet with a thickness of 1.8 mm, whereas conventional synchronizer rings require a sheet metal thickness of 2.2 mm, for example. The advantage of the method described can also be regarded as the fact that the robustness of the forming process is increased by the stamped depressions, with the result that other influencing variables, such as lubricants, punching quality, temperature or frictional forces do not have a significant effect on the quality of the synchronizer ring produced.

[0045] FIG. 5 is a sectioned view similar to FIG. 4 and shows another illustrative embodiment of a synchronizer ring, which has a depression 13 on the rear side 11 of the blocking tooth 2. The depression 13 is of drop-shaped design and has a spherical end and an opposite, pointed end. The pointed end is oriented radially inwards. As shown in FIG. 5, depression 13 has the shape of half a drop.

[0046] FIG. 6 is a sectioned view similar to FIG. 5 and shows a depression 14 which has the same half-drop shape as the depression 13 in FIG. 5. However, the pointed end is oriented radially outwards, while the spherical end faces radially inwards. As in the illustrative embodiments above, the drop-shaped depression 14 causes a material flow towards the top ridge 10 during the forming process.

[0047] FIG. 7 is a sectioned view of another illustrative embodiment of a synchronizer ring 1. On the rear side 11 there is a depression 15, the depth of which increases radially outwards in the axial direction along a curved path. The depression 15 extends as far as the radially outer end of the blocking tooth 2.

[0048] FIG. 8 is a sectioned view of another illustrative embodiment of a blocking tooth 2, in the rear side 11 of which a depression 16 is stamped, which is configured as a groove extending in the radial direction. In FIG. 8, it can be seen that the depth of the groove increases radially outwards. In this illustrative embodiment, the groove-shaped depression 16 has an at least approximately hemi-spherical cross section. The depression 16 also causes the desired material flow towards the top ridge 10 during the forming process, thereby resulting in particularly good die filling.

[0049] FIG. 9 is a sectioned view of an illustrative embodiment similar to that in FIG. 8. As in the preceding illustrative embodiment, a depression 17 is configured as a groove, the depth of which is constant. The groove-shaped depression 17 preferably has a rectangular or triangular or semicircular cross section (in a plan view of the front end of the blocking tooth or in a radial direction of view).

[0050] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0051] 1 synchronizer ring [0052] 2 blocking tooth [0053] 3 index tabs [0054] 4 recess [0055] 5 annular surface [0056] 6 collar [0057] 7 flank portion [0058] 8, 9 top flank [0059] 10 top ridge [0060] 11 rear side [0061] 12 depression [0062] 13 depression [0063] 14 depression [0064] 15 depression [0065] 16 depression [0066] 17 depression