Transmission and method for producing a transmission

Abstract

The invention relates to a transmission (1) having: a plurality of gears (2), each of which has a synchronizer ring (5); at least one synchronization element (6); and a movable sliding sleeve (4) for connecting the synchronization element (6) to the synchronizer ring (5), wherein there is a smaller pressure angle (α1) between toothing (10) of the sliding sleeve (4) and toothing (11) of the synchronization element (6) than between the toothing (10) of the sliding sleeve (4) and toothing (12) of the synchronizer ring (5).

Description

[0001] Gearbox and method for producing a gearbox

[0002] The invention relates to a transmission according to the preamble of claim 1, a vehicle according to the preamble of claim 6 and a method for producing a transmission according to the preamble of claim 8.

[0003] Transmissions require multiple gear ratios. Different gear ratios are selected by connecting different gears with shift elements. Sliding sleeves connect a synchronizer body, which is connected to a shaft, such as a drive shaft, with a synchronizer ring, which is connected to a gear. Sliding sleeves sometimes move inadvertently out of the engaged position.

[0004] EP 1 460 314 A2 describes a differential device with a limited-slip differential mechanism comprising a differential case, a pair of side gears housed in the differential case and connected to drive shafts, and pinions meshing with the pair of side gears. One of the tooth surfaces of each tooth of the side gears and pinions has a large pressure angle, and the other surface has a small pressure angle, so that the engagement reaction forces are greater in drive mode than in idle mode, resulting in different limit forces.

[0005] DE 10 2012 205 425 A1 describes a sliding sleeve in a synchronized vehicle transmission with at least one clutch body connected in a rotationally fixed manner to a loose wheel, at least one synchronizer ring and a synchronizer body connected in a rotationally fixed manner to a shaft, wherein the sliding sleeve has an internal toothing provided with end-side tapered portions, which is axially displaceable on a complementary external toothing of the synchronizer body until it engages, first, with an external toothing of the synchronizer ring and further until it engages with an external toothing of the clutch body, in order to positively couple the clutch body to the synchronizer body, wherein the internal toothing of the sliding sleeve has circumferentially evenly spaced tooth groups with teeth of different widths, wherein the external toothing of the synchronizer body is formed only where the internal toothing of the sliding sleeve has the tooth groups with the narrow teeth,The synchronizer body is toothless in the areas of the tooth groups of the sliding sleeve with wider teeth, and the wider teeth of the internal toothing of the sliding sleeve are provided with backings. To achieve improved lubrication between the internal toothing of the sliding sleeve and the external toothing of the synchronizer body, depressions forming oil pockets are provided on the axially parallel side surfaces of the narrow teeth of the sliding sleeve. These depressions on the narrow teeth are created by backing milling during the backing milling of the backings on the wide teeth without increasing the cycle time.

[0006] The invention is based on the object of providing a novel solution to prevent unintentional disengagement of a sliding sleeve from an engaged position.

[0007] The object is achieved according to the invention by a transmission having the features of claim 1, by a vehicle having the features of claim 6 and by a method for producing a transmission having the features of claim 8.

[0008] Advantageous embodiments of the invention are the subject of the subclaims.

[0009] A transmission is proposed, comprising a plurality of gear wheels with a respective synchronization ring, as well as at least one synchronization body and a displaceable sliding sleeve for connecting the synchronization body to the synchronization ring.

[0010] According to the invention, a smaller pressure angle is provided between a toothing of the sliding sleeve and a toothing of the synchronization body than between the toothing of the sliding sleeve and the toothing of the synchronization ring. For example, the toothing of the sliding sleeve can have a region with the smaller pressure angle and a region with the larger pressure angle at different positions.

[0011] In one embodiment, the smaller pressure angle is 20° and the larger pressure angle is 30°. The pressure angles can be determined based on the component strength and manufacturing capabilities.

[0012] The smaller pressure angle leads to a reduced centering function, which means that the sliding sleeve is better held in its switching position.

[0013] There is play between the teeth of the sliding sleeve and the teeth of the synchronization ring. Otherwise, the sliding sleeve cannot be slid onto the synchronization ring. There is also play in the teeth of the sliding sleeve and the synchronizer hub, otherwise, sliding is also impossible.

[0014] For example, the teeth of the sliding sleeve can have a backing in the area designed to engage with the teeth of the synchronization ring. In particular, a backing is present in the synchronization ring as well as in the toothing areas in contact with the sliding sleeve.

[0015] According to one aspect of the present invention, a vehicle, for example a commercial vehicle, a bus or a passenger car, with a transmission is proposed, wherein the transmission is designed as described above.

[0016] According to one aspect of the present invention, a method for producing a transmission is proposed, comprising a plurality of gears with a respective synchronization ring, as well as at least one synchronization body and a displaceable sliding sleeve for connecting the synchronization body to the synchronization ring.

[0017] According to the present invention, the geometries of existing components are modified, thus avoiding the costs associated with additional parts, as well as wear and damage to such additional parts. According to the invention, a smaller pressure angle is created between a toothing of the sliding sleeve and a toothing of the synchronization body than between the toothing of the sliding sleeve and a toothing of the synchronization ring. The toothing of the sliding sleeve therefore has two different pressure angles at different positions.

[0018] In addition, a gear play is created between the teeth of the sliding sleeve and the teeth of the synchronization ring.

[0019] Embodiments of the invention are explained in more detail below with reference to drawings.

[0020] Showing:

[0021] Fig. 1 is a schematic view of a gearbox with a sliding sleeve, a synchronization body, gears and synchronization rings,

[0022] Fig. 2 is a schematic view of the synchronization rings, the synchronization body and the sliding sleeve seen from the rotation axis of the sliding sleeve, and

[0023] Fig. 3 is a schematic view of the gearing of the sliding sleeve.

[0024] Corresponding parts are provided with the same reference numerals in all figures.

[0025] Figure 1 is a schematic view of a transmission 1, comprising a plurality of gears 2, in particular idler gears, which run on a drive shaft 3. The drive shaft 3 can be driven by an electric motor 15. The gears 2 each have a synchronization ring 5. Furthermore, at least one synchronization body 6 is provided, which is arranged between two gears 2 on the drive shaft 3 and rotates together with the drive shaft 3. By means of a displaceable sliding sleeve 4, the synchronization body 6 can be selectively brought into engagement with one or the other synchronization ring 5 of one of the gears 2 or disengaged from both synchronization rings 5. The gears 2, designed as idler gears, mesh with a respective further gear 7, wherein the further gears 7 are arranged on a shaft 8 parallel to the drive shaft 3, to which shaft 8 an output 9 can be coupled.

[0026] To realize multiple gear ratios, the transmission 1 has different gears 2, which can be connected by shifting elements, in particular sliding sleeves 4. The sliding sleeve 4 connects the synchronization body 6 to a synchronization ring 5, which is connected to a gear 2.

[0027] The sliding sleeve 4 has a toothing 10 which engages with a toothing 11 of the synchronization body 6 and optionally with a toothing 12 of one or none of the synchronization rings 5.

[0028] According to the invention, a different, in particular smaller, pressure angle a1 is provided between the toothing 10 of the sliding sleeve 4 and the toothing 11 of the synchronization body 6 than a pressure angle a2 between the toothing 10 of the sliding sleeve 4 and the toothing 12 of the synchronization ring 5. The toothing 10 of the sliding sleeve 4 therefore has two different pressure angles a1, a2 at different positions. The pressure angle of an involute 19 toothing is a normatively defined term, e.g., in DIN 3960. Reference is made there to the reference profile associated with each involute. For example, the pressure angle a1 for engagement with the toothing 11 of the synchronization body can be 620°, and the pressure angle a2 for engagement with the toothing 12 of the synchronization rings 5 ​​can be 30°. For example, the pressure angle a1 , a2 can be a normal pressure angle of an involute gear.

[0029] Figure 2 is a schematic view of the synchronization rings 5, the synchronization body 6 and the sliding sleeve 4 with the toothing 10 of the sliding sleeve 4 and the toothing 12 of the synchronization rings 5 ​​seen from the rotation axis of the sliding sleeve 4.

[0030] Figure 3 is a schematic view of the toothing 10 of the sliding sleeve 4 with a central region 13 with a smaller pressure angle a1 for engagement with the toothing 11 of the synchronization body 6 and an outer region 14 with a larger pressure angle a2 for engagement with the toothing 12 of one of the synchronization rings 5. Additionally, gear play can be provided on the sliding sleeve 4 and on the synchronization ring 5. For this purpose, the toothing 10 of the sliding sleeve 4 can have a backing in the outer region 14 with the larger pressure angle a2, i.e., the teeth of the toothing 10 become narrower in width.

[0031] The smaller pressure angle a1 leads to a reduced self-centering function according to DIN5466, whereby the sliding sleeve 4 is better held in its switching position.

Claims

Patent claims 1. Gearbox (1), comprising a plurality of gear wheels (2) with a respective synchronization ring (5), as well as at least one synchronization body (6) and a displaceable sliding sleeve (4) for connecting the synchronization body (6) to the synchronization ring (5), characterized in that a smaller pressure angle (a1) is provided between a toothing (10) of the sliding sleeve (4) and a toothing (11) of the synchronization body (6) than between the toothing (10) of the sliding sleeve (4) and a toothing (12) of the synchronization ring (5).

2. Gearbox (1) according to claim 1, characterized in that the toothing (10) of the sliding sleeve (4) has a region (13) with the smaller pressure angle (a1) and a region (14) with the larger pressure angle (a2) at different positions.

3. Transmission (1) according to claim 1 or 2, characterized in that the smaller pressure angle (a1) is 20° and the larger pressure angle (a2) is 30°.

4. Transmission (1) according to one of the preceding claims, characterized in that a gear play is provided between the toothing (10) of the sliding sleeve (4) and the toothing (12) of the synchronization ring (5).

5. Transmission (1) according to claim 4, characterized in that the toothing (10) of the sliding sleeve (4) has a backing in the area (14) designed to engage with the toothing (12) of the synchronization ring (5).

6. Vehicle with a transmission (1), characterized in that the transmission (1) is designed according to claim 1 or 2.

7. Vehicle according to claim 3, characterized in that the vehicle is designed as a commercial vehicle.

8. Method for producing a transmission (1), comprising a plurality of gear wheels (2) with a respective synchronization ring (5), as well as at least one synchronization body (6) and a displaceable sliding sleeve (4) for connecting the synchronization body (6) to the synchronization ring (5), characterized in that a smaller pressure angle (a1) is formed between a toothing (10) of the sliding sleeve (4) and a toothing (11) of the synchronization body (6) than between the toothing (10) of the sliding sleeve (4) and a toothing (12) of the synchronization ring (5).

9. Method according to claim 8, characterized in that on the toothing (10) of the sliding sleeve (4) a region (13) with the smaller pressure angle (a1) and a region (14) with the larger pressure angle (a2) are formed at different positions.

10. Method according to claim 8 or 9, characterized in that a gear play is generated between the toothing (10) of the sliding sleeve (4) and the toothing (12) of the synchronization ring (5).

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