SYNCHRONIZING DEVICE AS WELL AS A GEAR CHANGING TRANSMISSION FOR A VEHICLE

Abstract

Synchronizing device (1) of a gear changing transmission for a motor vehicle. The synchronizing device (1) of a gear changing transmission for a motor vehicle including an inner synchronizer ring (2), a middle synchronizer ring (3) and an outer synchronizer ring (4). The middle synchronizer ring (3) includes a first conical middle ring body (301) with a first inner surface of the middle ring (3011) and a first outer surface of the middle ring (3012), which each bound the first middle ring body (301) in a radial direction extending to the axial ring axis (8), wherein the first inner surface of the middle ring (3011) extends at a first inner angle (.sub.3011) of the middle ring and the first outer surface of the middle ring (3012) at a first outer angle (.sub.3012) of the inner ring to the ring axis (8). In order to further increase the synchronizing moment to be transmitted the first inner angle (.sub.3011) of the middle ring and the first outer angle (.sub.3012) of the middle ring are different according to the invention.

Claims

1. Synchronizing device (1) for a gear changing transmission of a motor vehicle, comprising an inner synchronizer ring (2), a middle synchronizer ring (3) and an outer synchronizer ring (4), wherein in an operating mode the outer synchronizer ring (4) and the inner synchronizer ring (2) are connected essentially torque proof with a first shifting element (6), and in the operating mode the middle synchronizer ring (3) is connected essentially torque proof with a second shifting element (7), and whereby the middle synchronizer ring (3) comprises a first conical middle ring body (301) with a first inner surface of the middle ring (3011) and a first outer surface of the middle ring (3012), which each bound the first middle ring body (301) in a radial direction extending to an axial ring axis (8), wherein the first inner surface of the middle ring (3011) extending at a first inner angle (.sub.3011) of the middle ring and the first outer surface of the middle ring (3012) at a first outer angle (.sub.3012) of the middle ring to the ring axis (8), and in the operating mode the first inner surface of the middle ring (3011) is interacting with the inner synchronizer ring (2) and the first outer surface of the middle ring (3012) is directly or indirectly interacting with the outer synchronizer ring (4), characterized in that the first inner angle (.sub.3011) of the middle ring and the first outer angle (.sub.3012) of the middle ring are different.

2. Synchronizing device according to claim 1, wherein the first inner angle (.sub.3011) of the middle ring is smaller than the first outer angle (.sub.3012) of the middle ring.

3. Synchronizing device according to claim 1, wherein the middle synchronizer ring (3) is made of the first conical middle ring body (301) and a second conical middle ring body (302), the second middle ring body (302) comprising a second inner surface of the middle ring (3021) and a second outer surface of the middle ring (3022), which each bound the second middle ring body (302) in a radial direction extending to the axial ring axis (8), wherein the second inner surface of the middle ring (3021) extending at a second inner angle (.sub.3021) of the middle ring and the second outer surface of the middle ring (3022) at a second outer angle (.sub.3022) of the middle ring to the ring axis (8), wherein the second inner angle (.sub.3021) of the middle ring corresponds to the first outer angle (.sub.3012) of the middle ring, and in the operating mode the second inner surface of the middle ring (3021) is form-locking connected, at least partially, to the first outer surface of the middle ring (3012) and the second outer surface of the middle ring (3022) interacts with the outer synchronizer ring (4).

4. Synchronizing device according to claim 1, wherein the inner synchronizer ring (2) is made of a first conical inner ring body (201) and a second conical inner ring body (202), wherein the first inner ring body (201) comprises a first inner surface of the inner ring (2011) and a first outer surface of the inner ring (2012), which bound the first inner ring body (201) in a radial direction extending to the axial ring axis (8), wherein the first inner surface of the inner ring (2011) extending at a first inner angle (.sub.2011) of the inner ring and the first outer surface of the inner ring (2012) at a first outer angle (.sub.2012) of the inner ring to the ring axis (8), and the second inner ring body (202) comprising a second inner surface of the inner ring (2021) and a second outer surface of the inner ring (2022), which each bound the second inner ring body (202) in a radial direction extending to the axial ring axis (8), wherein the second inner surface of the inner ring (2021) extending at a second inner angle (.sub.2021) of the inner ring and the second outer surface of the inner ring (2022) at a second outer angle (.sub.2022) of the inner ring to the ring axis (8), wherein the second inner angle (.sub.2021) of the inner ring corresponds to the first outer angle (.sub.2012) of the inner ring, and in the operating mode the first inner surface of the inner ring (2011) interacts with the second shifting element (7), and the second inner surface of the inner ring (2021) is form-locking connected to the first outer surface of the inner ring (2012) and the second outer surface of the inner ring (2022) interacts with the first inner surface of the middle ring (3011).

5. Synchronizing device according to claim 1, the synchronizing device (1) comprising an intermediate synchronizer ring (9) with a conical intermediate ring body (901), the intermediate ring body (901) comprising an inner surface of the intermediate ring (9011) and an outer surface of the intermediate ring (9012), which each bound the intermediate ring body (901) in a radial direction extending to the axial ring axis (8), wherein the inner surface of the intermediate ring (9011) extending at an inner angle (.sub.9011) of the intermediate ring and the outer surface of the intermediate ring (9012) at an outer angle (.sub.9012) of the intermediate ring to the ring axis (8), wherein in the operating mode the intermediate synchronizer ring (9) is arranged between the outer synchronizer ring (4) and the middle synchronizer ring (3) and is connected torque proof to the inner synchronizer ring (2) and the outer synchronizer ring (4), wherein the inner angle (.sub.9011) of the intermediate ring corresponds to the first outer angle (.sub.3012) of the middle ring and the outer angle (.sub.9012) of the intermediate ring to an inner angle (.sub.4011) of the outer ring, so that in the operating mode the inner surface of the intermediate ring (9011) interacts with the first outer surface of the middle ring (3012), and the outer surface of the intermediate ring (9012) is form-locking connected, at least partially, to the outer synchronizer ring (4).

6. Synchronizing device according to claim 1, wherein the first inner angle (.sub.2011) of the inner ring and/or the first outer angle (.sub.2012) of the inner ring and/or the second outer angle (.sub.2022) of the inner ring and/or the first inner angle (.sub.3011) of the middle ring and/or the first outer angle (.sub.3012) of the middle ring and/or the second outer angle (.sub.3022) of the middle ring and/or the inner angle (.sub.9011) of the intermediate ring and/or the outer angle (.sub.9012) of the intermediate ring is 3-5.

7. Synchronizing device according to claim 1, wherein the first inner ring body (201) and/or the second inner ring body (202) and/or the first middle ring body (301) and/or the second middle ring body (302) and/or the intermediate ring body (901) has a cutoff in a circumferential direction extending vertical to the axial ring axis (8).

8. Synchronizing device according to claim 7, wherein the cutoff is open or closed in the non-operating mode.

9. Synchronizing device according to claim 1, wherein the first inner ring body (201) and/or the second inner ring body (202) and/or the first middle ring body (301) and/or the second middle ring body (302) and/or the intermediate ring body (901) having at least one limit stop for fixing in direction to the ring axis (8).

10. Synchronizing device according to claim 1, wherein a friction layer, especially a friction layer in the form of a carbon friction layer, is provided at the first inner surface of the inner ring (2011) and/or at the first outer surface of the inner ring (2012) and/or at the second inner surface of the inner ring (2021) and/or at the second outer surface of the inner ring (2022) and/or at the first inner surface of the middle ring (3011) and/or at the first outer surface of the middle ring (3012) and/or at the second inner surface of the middle ring (3021) and/or at the second outer surface of the middle ring (3022) and/or at the inner surface of the intermediate ring (9011) and/or at the outer surface of the intermediate ring (9012).

11. Synchronizing device according to claim 1, wherein an adhesion reducing surface structure is provided at the first inner surface of the inner ring (2011) and/or at the first outer surface of the inner ring (2012) and/or at the second inner surface of the inner ring (2021) and/or at the second outer surface of the inner ring (2022) and/or at the first inner surface of the middle ring (3011) and/or at the first outer surface of the middle ring (3012) and/or at the second inner surface of the middle ring (3021) and/or at the second outer surface of the middle ring (3022) and/or at the inner surface of the intermediate ring (9011) and/or at the outer surface of the intermediate ring (9012).

12. Gear changing transmission for a motor vehicle with a synchronizing device (1) according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention is explained in more detail below with reference to the schematic drawing. It is shown:

[0029] FIG. 1 a cross-section of a synchronizing device known from the state of the art;

[0030] FIG. 2a a cross-section of a first embodiment of a synchronizing device according to the invention having two functional friction surfaces;

[0031] FIG. 2b a cross-section of a second embodiment of a synchronizing device according to the invention having two functional friction surfaces;

[0032] FIG. 2c a cross-section of a third embodiment of a synchronizing device according to the invention having two functional friction surfaces;

[0033] FIG. 2d a cross-section of a fourth embodiment of a synchronizing device according to the invention having two functional friction surfaces;

[0034] FIG. 3a a cross-section of a first embodiment of a synchronizing device according to the invention having three functional friction surfaces;

[0035] FIG. 3b a cross-section of a second embodiment of a synchronizing device according to the invention having three functional friction surfaces;

[0036] FIG. 3c a cross-section of a third embodiment of a synchronizing device according to the invention having three functional friction surfaces;

[0037] FIG. 3d a cross-section of a fourth embodiment of a synchronizing device according to the invention having three functional friction surfaces;

[0038] FIG. 3e a cross-section of a fifth embodiment of a synchronizing device according to the invention having three functional friction surfaces;

[0039] FIG. 3f a cross-section of a sixth embodiment of a synchronizing device according to the invention having three functional friction surfaces;

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In the following it is referred to FIG. 1 to explain a synchronizing device known from the state of the art. In order to distinguish the state of the art from the present invention the reference signs referring to features of a synchronizing device known from the state of the art have an inverted comma, while features of embodiments according to the invention have reference sign without an inverted comma.

[0041] FIG. 1 shows a cross-section of a synchronizing device 1 known from the state of the art comprising an inner synchronizer ring 2, a middle synchronizer ring 3 and an outer synchronizer ring 4. In a manner known per se the synchronizing device 1 also has a sliding sleeve 5 with a synchronizer body 6 and a gear wheel 7. The outer synchronizer ring 4 and the inner synchronizer ring 2 are connected essentially torque proof with the synchronizer body 6 and the middle synchronizer ring 3 is connected essentially torque proof with the gear wheel 7. The components mentioned above are coaxially arranged to a ring axis 8 in such a way, the inner synchronizer ring 2 and the outer synchronizer ring 4 being displaceable together along the ring axis 8 in direction to the gear wheel 7 by the sliding sleeve 5 during the synchronizing process, so that the inner synchronizer ring 2 and the outer synchronizer ring 4 can be engaged with the gear wheel 7.

[0042] The middle synchronizer ring 3 also comprises a first conical middle ring body 301 having a first inner surface of the middle ring 3011 and a first outer surface of the middle ring 3012, which each bound the first middle ring body 301 in a radial direction extending to the radial ring axis 8. The first inner surface of the middle ring 3011 extends at a first inner angle .sub.3011 of the middle ring and the first outer surface of the middle ring 3012 extends at a first outer angle .sub.3012 of the middle ring to the ring axis 8, wherein the first inner angle .sub.3011 of the middle ring and the first outer angle .sub.3012 of the middle ring are the same size, i.e. the first inner surface of the middle ring 3011 and the first outer surface of the middle ring 3012 are parallel to each other.

[0043] The inner synchronizer ring 2 comprises a first conical inner ring body 201 having a first inner surface of the inner ring 2011 and a first outer surface of the inner ring 2012, which each bound the first inner ring body 201 in the radial direction extending to the radial ring axis 8. The first inner surface of the inner ring 2011 extends at a first inner angle .sub.2011 of the inner ring and the first outer surface of the inner ring 2012 extends at a first outer angle .sub.2012 of the inner ring to the ring axis 8, wherein the first inner angle .sub.2011 of the inner ring is 0 and the first outer angle of the inner ring .sub.2012 is the same size as the first inner angle .sub.3011 of the middle ring.

[0044] The outer synchronizer ring 4 comprises an outer ring body 401 having an inner surface of the outer ring 4011, extending at an inner angle .sub.4011 of the outer ring to the ring axis 8, the inner angle .sub.4011 of the outer ring being the same size as the first outer angle .sub.3012 of the middle ring.

[0045] Thus, the inner and the outer synchronizer ring 2, 4 are designed and arranged, that the first inner surface of the middle ring 3011 is in friction contact with the first outer surface of the inner ring 2012 and the first outer surface of the middle ring 3012 is directly in friction contact with the inner surface of the outer ring 4011 during a synchronization process when displacing the inner and the outer synchronizer ring 2, 4 in direction to the gear wheel 7 to be synchronized. For this purpose, the surfaces being in friction contact have a friction layer 10, namely the first outer surface of the inner ring 2012 and the first inner surface of the middle ring 3011 or the first outer surface of the middle ring 3012 and the inner surface of the outer ring 4011, respectively. In order to ensure a secure transmission of the synchronizing device from the operating mode to the non-operating mode the first inner angle .sub.3011 of the middle ring and the first outer angle .sub.3012 of the middle ring are large angles. I.e. the synchronizing device according to the state of the art is a configuration of a synchronizing device with two friction/loosening surfaces.

[0046] FIG. 2a shows a cross-section of a first embodiment of a synchronizing device according to the invention 1 having two functional friction surfaces.

[0047] The synchronizing device 1 comprises an inner synchronizer ring 2, a middle synchronizer ring 3 and an outer synchronizer ring 4. The synchronizing device 1 also has a sliding sleeve 5 with a synchronizing body 6 and a gear wheel 7 as already described above with reference to FIG. 1. The outer synchronizer ring 4 and the inner synchronizer ring 2 are connected essentially torque proof with the synchronizing body 6 and the middle synchronizer ring 3 is connected essentially torque proof with the gear wheel 7. The components mentioned above are coaxially arranged to a ring axis 8 in such a way, the inner synchronizer ring 2 and the outer synchronizer ring 4 being displaceable together along the ring axis 8 in direction to the gear wheel 7 by the sliding sleeve 5 during the synchronizing process, so that the inner synchronizer ring 2 and the outer synchronizer ring 4 can be engaged with the gear wheel 7.

[0048] The middle synchronizer ring 3 comprises a first conical middle ring body 301 having a first inner surface of the middle ring 3011 and a first outer surface of the middle ring 3012, which each bound the first middle ring body 301 in a radial direction extending to the radial ring axis 8. The first inner surface of the middle ring 3011 extends at a first inner angle .sub.3011 of the middle ring and the first outer surface of the middle ring 3012 extends at a first outer angle .sub.3012 of the middle ring to the ring axis 8, wherein in contrast to the synchronizing device 1 from the state of the art (FIG. 1) the first inner angle .sub.3011 of the middle ring and the first outer angle .sub.3012 of the middle ring are different, i.e. the first inner surface of the middle ring 3011 and the first outer surface of the middle ring 3012 are not parallel. In this embodiment the first inner angle .sub.3011 of the middle ring is 3 and the first outer angle .sub.3012 of the middle ring is 7.

[0049] The inner synchronizer ring 2 comprises a first conical inner ring body 201 having a first inner surface of the inner ring 2011 and a first outer surface of the inner ring 2012, which each bound the first inner ring body 201 in the radial direction extending to the axial ring axis 8. The first inner surface of the inner ring 2011 extends at a first inner angle .sub.2011 of the inner ring and the first outer surface of the inner ring 2012 extends at a first outer angle .sub.2012 of the inner ring to the ring axis 8, wherein the first inner angle .sub.2011 of the inner ring is 0 and the first outer angle of the inner ring .sub.2012 is the same size as the first inner angle of the middle ring .sub.3011.

[0050] The outer synchronizer ring 4 comprises an outer ring body 401 having an inner surface of the outer ring 4011, extending at an inner angle .sub.4011 of the outer ring to the ring axis 8, the inner angle .sub.4011 of the outer ring being the same size as the first outer angle .sub.3012 of the middle ring.

[0051] Thus, the inner and the outer synchronizer ring 2, 4 are designed and arranged, that the first inner surface of the middle ring 3011 is in friction contact with the first outer surface of the inner ring 2012 and the first outer surface of the middle ring 3012 is directly in friction contact with the inner surface of the outer ring 4011 during a synchronization process when displacing the inner and the outer synchronizer ring 2, 4 in direction to the gear wheel 7 to be synchronized. For this purpose, the surfaces being in friction contact have a friction layer 10, namely the first outer surface of the inner ring 2012 and the first inner surface of the middle ring 3011 or the first outer surface of the middle ring 3012 and the inner surface of the outer ring 4011, respectively.

[0052] This first embodiment of the synchronizing device 1 according to the invention is characterized in that it has a friction surface, i.e. a surface extending at a small angle to the axial ring axis 8 and serving only for transmitting the synchronizing moment, and it has one friction/loosening surface extending at a large angle to the axial ring axis 8 and serving for transmitting the synchronizing moment as well as for loosening. Thus, an increased synchronizing moment can be transmitted with the same shifting quality compares to the state of the art.

[0053] FIG. 2b shows a cross-section of a second embodiment of a synchronizing device 1 according to the invention having two functional friction surfaces. In contrast to the synchronizing device 1 from FIG. 2a the first inner angle .sub.3011 of the middle ring is large (7) and the first outer angle .sub.3012 of the middle ring is small (3). According to this the outer angle .sub.2012 of the inner ring is large and the inner angle .sub.4011 of the outer ring is small.

[0054] As the embodiment in FIG. 2a this embodiment also has a friction surface and a friction/loosening surface.

[0055] FIG. 2c shows a cross-section of a third embodiment of a synchronizing device 1 according to the invention having two functional friction surfaces. In contrast to the synchronizing device 1 from FIGS. 2a and 2b the synchronizing device 1 according to FIG. 2c has a two-piece middle synchronizer ring 3, i.e. the middle synchronizer ring 3 is made of a first conical middle ring body 301 and a second conical middle ring body 302. The second middle ring body 302 comprising a second inner surface of the middle ring 3021 and a second outer surface of the middle ring 3022 which each bound the second middle ring body 302 in the radial direction extending to the axial friction ring axis 8. The second inner surface of the middle ring 3021 extends at a second inner angle .sub.3021 of the middle ring and the second outer surface of the middle ring 3022 at a second outer angle .sub.3022 of the middle ring to the ring axis 8. Thereby the second inner angle .sub.3021 of the middle ring corresponds to the first outer angle .sub.3012 of the middle ring and the second outer angle .sub.3022 of the middle ring to the first inner angle .sub.3011 of the middle ring. In the operating mode the second inner surface of the middle ring 3021 is form-locking connected to the first outer surface of the middle ring 3012 and the second outer surface of the middle ring 3022 interacts with the outer synchronizer ring 4.

[0056] In this embodiment the first inner angle .sub.3011 of the middle ring and the second outer angle .sub.3022 of the middle ring are small, whereas the first outer angle .sub.3012 of the middle ring and the second inner angle .sub.3021 of the middle ring are large.

[0057] Thus, the synchronizing device 1 according to FIG. 2c has two friction surfaces and one loosening surface.

[0058] FIG. 2d shows a cross-section of a fourth embodiment of a synchronizing device 1 according to the invention having two functional friction surfaces.

[0059] In contrast to the synchronizing device 1 according to FIG. 2c, in the synchronizing device 1 according to FIG. 2d the second middle ring body 302 is connected essentially torque proof with the gear wheel 7 via the first middle ring body 301. Thus, in contrast to the synchronizing device 1 according to FIG. 2c the second inner surface of the middle ring 3021 is form-locking connected, only partially, to the first outer surface of the middle ring 3012 in the operating mode.

[0060] As shown in the embodiment according to FIG. 2c, the first inner angle .sub.3011 of the middle ring and the second outer angle .sub.3022 of the middle ring are small, whereas the first outer angle .sub.3012 of the middle ring and the second inner angle .sub.3021 of the middle ring are large in this embodiment.

[0061] Thus, the synchronizing device 1 according to FIG. 2d has two friction surfaces and one loosening surface.

[0062] FIGS. 3a-3g show cross-sections of further synchronizing devices 1 according to the invention having three functional friction surfaces.

[0063] The gear wheel 7 has a conical gear wheel shoulder 701 in all these synchronizing devices 1, so that a synchronizing moment can be transmitted to the inner synchronizer ring 2 in the operating mode. There the gear wheel shoulder 701 has a gear wheel shoulder surface 7011 extending at a gear wheel shoulder angle .sub.7011 to the ring axis 8.

[0064] FIG. 3a shows a cross-section of a first embodiment of a synchronizing device 1 according to the invention with three functional friction surfaces.

[0065] As shown in the embodiment according to FIG. 2b, the synchronizing device 1 has a middle synchronizer ring 3, whose first inner angle .sub.3011 of the middle ring is large and whose first outer angle .sub.3012 of the middle ring is small.

[0066] In contrast to the embodiment according to FIG. 2b the inner angle .sub.2011 of the inner ring and the outer angle .sub.2012 of the inner ring are the same size, i.e. the inner surface of the inner ring 2011 and the outer surface of the inner ring 2012 are parallel to each other. That is why, in contrast to the embodiment according to FIG. 2b, the inner surface of the inner ring 2011 extends at a large inner angle .sub.2011 of the inner ring, i.e. the inner angle .sub.2011 of the inner ring is not 0. Thus, the inner angle .sub.2011 of the inner ring corresponds to the gear wheel shoulder angle .sub.7011, so that the inner surface of the inner ring 2011 interacts with the gear wheel shoulder surface 7011 in the operating mode.

[0067] The synchronizing device 1 according to FIG. 3a has one friction surface and two friction/loosening surfaces.

[0068] FIG. 3b shows a cross-section of a second embodiment of a synchronizing device 1 according to the invention with three functional friction surfaces.

[0069] As shown in the embodiment according to FIG. 2a, the synchronizing device 1 has a middle synchronizer ring 3, whose first inner angle .sub.3011 of the middle ring is small and whose first outer angle .sub.3012 of the middle ring is large.

[0070] In contrast to the embodiment according to FIG. 2a the inner surface of the inner ring 2011 extends at a large inner angle .sub.2011 of the inner ring, i.e. the inner angle .sub.2011 of the inner ring is not 0. Thus, the inner angle .sub.2011 of the inner ring corresponds to the gear wheel shoulder angle .sub.7011, so that the inner surface of the inner ring 2011 interacts with the gear wheel shoulder surface 7011 in the operating mode.

[0071] As the synchronizing device 1 according to FIG. 3a, the synchronizing device 1 according to FIG. 3b also has one friction surface and two friction/loosening surfaces.

[0072] FIG. 3c shows a cross-section of a third embodiment of a synchronizing device 1 according to the invention having three functional friction surfaces.

[0073] As shown in the embodiment according to FIG. 3b, the synchronizing device 1 has a middle synchronizer ring 3, whose first inner angle .sub.3011 of the middle ring is small and whose first outer angle .sub.3012 of the middle ring is large.

[0074] In contrast to the synchronizing device 1 according to FIG. 3b, the synchronizing device 1 according to FIG. 3c has a two-piece inner synchronizer ring 2, i.e. the inner synchronizer ring 2 is made of a first conical inner ring body 201 and a second conical inner ring body 202.

[0075] The first inner ring body 201 has a first inner surface of the inner ring 2011 and a first outer surface of the inner ring 2012, which each bound the first inner ring body 201 in a radial direction extending to the axial ring axis 8, the first inner surface of the inner ring 2011 extending at a first inner angle .sub.2011 of the inner ring and the first outer surface of the inner ring 2012 at a first outer angle .sub.2012 of the inner ring to the ring axis 8. The second inner ring body 202 has a second inner surface of the inner ring 2021 and a second outer surface of the inner ring 2022, which each bound the second inner ring body 202 in a radial direction extending to the axial ring axis 8, the second inner surface of the inner ring 2021 extending at a second inner angle .sub.2021 of the inner ring and the second outer surface of the inner ring 2022 at a second outer angle .sub.2022 of the inner ring to the ring axis 8. Though the second inner angle .sub.2021 of the inner ring corresponds to the first outer angle .sub.2012 of the inner ring and the second outer angle .sub.2022 of the inner ring corresponds to the first inner angle .sub.2011 of the inner ring. The first inner surface of the inner ring 2011 interacts with the gear wheel 7 and the second inner surface of the inner ring 2021 is form-locking connected to the first outer surface of the inner ring 2012 in the operating mode. At the same time the second outer surface of the inner ring 2022 interacts with the first inner surface of the middle ring 3011.

[0076] Though the first inner angle .sub.2011 of the inner ring and the gear wheel shoulder angle .sub.7011 are small. At the same time the second outer angle .sub.2022 of the inner ring and the first inner angle .sub.3011 of the middle ring also are small angles.

[0077] Thus, the synchronizing device 1 according to FIG. 3c has two friction surfaces, one friction/loosening surface and one loosening surface.

[0078] FIG. 3d shows a cross-section of a fourth embodiment of a synchronizing device according to the invention having three functional friction surfaces.

[0079] As shown in the embodiment according to FIG. 2c, the middle synchronizer ring 3 has a second middle synchronizer body 302 additional to the first middle synchronizer body 301.

[0080] In contrast to the embodiment according to FIG. 2c, the inner surface of the inner ring 2011 extends at a large inner angle .sub.2011 of the inner ring, i.e. the inner angle .sub.2011 of the inner ring is not 0. The inner angle .sub.2011 of the inner ring corresponds to the gear wheel shoulder angle .sub.7011, so that the inner surface of the inner ring 2011 interacts with the gear wheel shoulder surface in the operating mode.

[0081] As the synchronizing device 1 according to FIG. 3c, the synchronizing device 1 according to FIG. 3d also has two friction surfaces, one friction/loosening surface and one loosening surface.

[0082] FIG. 3e shows a cross-section of a fifth embodiment of a synchronizing device 1 according to the invention having three functional friction surfaces.

[0083] In contrast to the synchronizing devices 1 from FIGS. 3a-3d the synchronizing device 1 according to FIG. 3e has an additional intermediate synchronizer 9 ring with a conical intermediate ring body 901. The intermediate ring body 901 has an inner surface of the intermediate ring 9011 and an outer surface of the intermediate ring 9012, which each bound the intermediate ring body 901 in a radial direction extending to the axial friction ring axis 8. The inner surface of the intermediate ring 9011 extends at an inner angle .sub.9011 of the intermediate ring and the outer surface of the intermediate ring 9012 at an outer angle .sub.9012 of the intermediate ring to the ring axis 8. In this embodiment, the inner angle .sub.9011 of the intermediate ring is small and the outer angle .sub.9012 of the intermediate ring is large. The intermediate synchronizer ring 9 is arranged between the outer synchronizer ring 4 and the middle synchronizer ring 3 and is connected torque proof with the inner synchronizer ring 2 and the synchronizer ring 4 in the operating mode. The inner angle .sub.9011 of the intermediate ring corresponds to the first outer angle .sub.3012 of the middle ring and the outer angle .sub.9012 of the intermediate ring to the inner angle .sub.4011 of the outer ring. Thus, in the operating mode the inner surface of the intermediate ring 9011 interacts with the first outer surface of the middle ring 3012 and the outer surface of the intermediate ring 9012 is form-locking connected, at least partially, to the outer synchronizer ring.

[0084] The first inner surface of the inner ring 2011 extends at a small inner angle .sub.2011 of the inner ring. Though the inner angle .sub.2011 of the inner ring corresponds to the gear wheel shoulder angle .sub.7011, so that the inner surface of the inner ring 2011 and the gear wheel shoulder surface 7011 are interacting in the operating mode. At the same time the outer surface of the inner ring 2012 interacting with the first inner surface of the middle ring 3011 in the operating mode is drifting at a large outer angle .sub.2012 of the inner ring.

[0085] As the synchronizing device 1 according to FIG. 3c and FIG. 3d, the synchronizing device 1 according to FIG. 3e also has two friction surfaces, one friction/loosening surface and one loosening surface.

[0086] FIG. 3f shows a cross-section of a sixth embodiment of a synchronizing device 1 according to the invention having three functional friction surfaces.

[0087] As the synchronizing device 1 according to FIG. 2c, the synchronizing device 1 according to FIG. 3f also has a two-piece middle synchronizer ring 3, i.e. the middle synchronizer ring 3 is made of a first conical middle ring body 301 and a second conical middle ring body 302.

[0088] In contrast to the synchronizing device 1 according to FIG. 2c the inner synchronizer ring 2 also is designed two-piece. i.e. the inner synchronizer ring 2 comprising a first conical inner ring body 201 and a second conical inner ring body 202, as already described with the the synchronizing device 1 according to FIG. 3c.

[0089] The first inner surface of the inner ring 2011 extends at a small inner angle .sub.2011 of the inner ring. Though the first inner angle .sub.2011 of the inner ring corresponds to the gear wheel shoulder angle .sub.7011, so that the first inner surface of the inner ring 2011 and the gear wheel shoulder surface 7011 are interacting in the operating mode. The second outer surface of the inner ring 2022 interacting with the first inner surface of the middle ring 3011 in the operating mode also extends at a small outer angle .sub.2022 of the inner ring.

[0090] Thus, the synchronizing device 1 has three friction surfaces and two loosening surfaces.

[0091] In all embodiments mentioned above, a friction layer 10 can be provided one-sided and/or two-sided at the surfaces being in contact to each other in the operating mode. It is also possible providing an adhesion reducing surface structure at those surfaces, which do not serve as friction surfaces (loosening surfaces).

[0092] Furthermore, in all embodiments described above the first inner ring body 201 and/or the second inner ring body 202 and/or the first middle ring body 301 and/or the second middle ring body 302 and/or the intermediate ring body 901 may have a cutoff in a circumferential direction extending vertical to the axial ring axis 8, wherein the cutoff is open or closed in the non-operating mode.

[0093] Finally, in all embodiments described above the first inner ring body 201 and/or the second inner ring body 202 and/or the first middle ring body 301 and/or the second middle ring body 302 and/or the intermediate ring body 901 may have at least one limit stop for fixing in direction to the ring axis 8.