CN114074248A

CN114074248A - Method for producing a sliding sleeve for a synchronization unit, sliding sleeve and synchronization unit

Info

Publication number: CN114074248A
Application number: CN202011170324.1A
Authority: CN
Inventors: 罗伯特·诺兹; 斯特凡·努塞尔; 彼得·埃希特勒; 托马斯·韦茨勒
Original assignee: Hoerbiger Antriebstechnik Holding GmbH
Current assignee: Hoerbiger Antriebstechnik Holding GmbH
Priority date: 2020-08-12
Filing date: 2020-10-28
Publication date: 2022-02-22
Also published as: DE102020121239A1

Abstract

The invention relates to a method for producing a sliding sleeve (12) for a synchronization unit. A sliding sleeve body (16) having an engagement contour (19) for a shift fork is produced by means of cutting or powder metallurgy. At least one section of the surface (21a, 21b, 21c) of the joining contour (19) bounding the joining contour (19) and/or at least one section of the sliding sleeve body (16) directly adjoining the surface of the joining contour (19) is then plastically deformed. Furthermore, a sliding sleeve (12) for a synchronization unit is proposed, which has a sliding sleeve body (16) on which an engagement contour (19) for a shift fork is provided. Furthermore, a synchronization unit having such a sliding sleeve (12) is proposed.

Description

Method for producing a sliding sleeve for a synchronization unit, sliding sleeve and synchronization unit

Technical Field

The invention relates to a method for producing a sliding sleeve for a synchronization unit, wherein a sliding sleeve body is produced by means of cutting or powder metallurgy, wherein the sliding sleeve body has an engagement contour for a shift fork.

Background

Furthermore, the invention is directed to a sliding sleeve for a synchronization unit, having a sliding sleeve body on which an engagement contour for a shift fork is provided. The engagement contour is designed to interact with a section of the shift fork.

The invention also relates to a synchronization unit having such a sliding sleeve and a shift fork, wherein the shift fork engages on an engagement contour.

In this context, the shift fork is used to move the sliding sleeve during the synchronization process.

Such synchronization units and sliding sleeves are known from the prior art. The same applies to the mentioned method for producing a sliding sleeve.

In general, the manufacture of sliding sleeves comprises a roughing step, which can be performed by means of cutting or powder metallurgy. In particular, the sliding sleeve body blank forged here is subjected to a cutting roughing step. The result of the roughing step is a sliding sleeve body with an engagement profile for the shift fork. The sliding sleeve is optionally hardened. Furthermore, the sliding sleeve body must undergo a finishing step in order to achieve the desired dimensional accuracy and a preset roughness at least on the faces abutting the engagement profile. Finishing is usually performed by grinding or hard turning. This achieves a reliable and low-wear interaction of the shift fork with the engagement contour.

Disclosure of Invention

The object of the invention is to further improve the production of the sliding sleeve. In particular, a simple and cost-effective method for producing the sliding sleeve should be provided. The improvement addressed here, however, is not carried out during operation with regard to the cost of the reliability of the sliding sleeve or the cost of the synchronization unit equipped with the sliding sleeve. Likewise, an improved production method results in less wear and tear during operation of the sliding sleeve or of the synchronization unit provided with the sliding sleeve.

The object is achieved by a method for producing a sliding sleeve for a synchronization unit, having the following steps:

a) producing a sliding sleeve body by means of cutting or powder metallurgy, wherein the sliding sleeve body has an engagement contour for a shift fork, and then

b) At least one section of the surface of the engagement contour bounding the engagement contour and/or at least one section of the sliding sleeve body directly adjoining the surface of the engagement contour is plastically deformed.

The plastic deformation ensures a high dimensional accuracy of the deformed face section. Furthermore, the segments are flattened, i.e. the roughness of the segments is reduced. Due to this effect, the engagement profile can interact with the shift fork via a relatively high load-bearing ratio. Thus, a greater share of the engagement contour takes part in the force transmission between the shift fork and the sliding sleeve than in the known synchronization units. A sliding sleeve is obtained overall which can be operated with low wear. Furthermore, the efficiency of the associated synchronization unit is increased due to the high dimensional accuracy and smoothness of the sections of the faces bounding the engagement contour. At the same time, the method according to the invention can be carried out particularly simply and at low cost, in particular in comparison with known finishing methods, such as grinding or hard turning.

Plastic deformation is especially cold press forming.

The mentioned method relates precisely to the finishing of the sliding sleeve body, which is manufactured by means of cutting or powder metallurgy. Accordingly, the cutting method or the powder metallurgy method can be regarded as rough machining. In this case, powder metallurgy is in particular a sintering process, wherein the joining profile is also produced during sintering. Alternatively, the joining contour can be introduced by a cutting method after sintering or in the green body. The sliding sleeve body produced by means of a cutting process can be machined from a forged or cast blank. It is therefore not particularly relevant how the sliding sleeve body blank is produced.

The cutting method may be a turning method. In the intermediate product thus obtained, the surfaces bounding the joining contour do not yet have the required final dimensional accuracy and roughness. This is only achieved by the finishing, which is carried out by plastic deformation in the method according to the invention.

The plastic deformation of at least one section of the surface bounding the joining contour is preferably carried out without material removal. No chips are produced during the course of the method. Thus, no method steps or measures are required, which involve the removal of chips from the workpiece or from the production machine. For this reason, a simple and cost-effective method sequence is also obtained.

Preferably, the plastic deformation is performed by finishing. Finishing is understood here to mean a deformation process in which the edge layer of the workpiece is deformed and plasticized by means of a finishing tool. The finishing tool is for example a roller or a ball. Here, a compressive stress is generated at the contact point between the finishing tool and the workpiece, which compressive stress causes plastic deformation when the yield limit of the material being worked is exceeded. In this case, the existing roughness peaks are pressed down approximately perpendicular to the surface, so that the roughness valleys associated with the resulting material flow are substantially raised from below. The surface is thus smoothed by the flow of the entire material layer close to the surface. The finishing can be carried out particularly quickly and economically at R_zA roughness depth in the range of < 10 μm.

The oil feed structure can be shaped into the finished section during and by finishing. This is particularly effected without chipping. A separate method step for introducing the oil supply structure can thereby be dispensed with. The production of the sliding sleeve is thereby particularly efficient and cost-effective.

Alternatively or additionally, the finished section is cold work hardened during finishing. Thus, the finished section is hardened with respect to its initial state. No separate method step is required for this purpose. This is particularly suitable in comparison with known methods for producing sliding sleeves, in which the sliding sleeve body is hardened between the roughing step and the finishing step in the context of a separate method step.

Preferably, the engagement profile is formed by a shift fork slot. In particular the entire bottom and/or the entire side wall of the shift rail is plastically deformed. The shift rail as a whole thus has a high dimensional accuracy and a low surface roughness. The shift fork pocket is suitable for a reliable interaction with a conventional shift fork.

Alternatively, the engagement contour is formed by a shift fork web. In particular, the entire cover surface of the shift fork web, the entire side wall of the shift fork web and/or the surface of the sliding sleeve body directly adjoining the shift fork web is then plastically deformed. As a result, the shift fork web as a whole has a high dimensional accuracy and a low surface roughness. The shift fork web is also suitable for a reliable interaction with a conventional shift fork.

The object is also achieved by a sliding sleeve for a synchronization unit, having a sliding sleeve body on which an engagement contour for a shift fork is provided, which engagement contour is designed to interact with a section of the shift fork, wherein the sliding sleeve body has an edge layer on at least one section of the engagement contour bounding a surface of the engagement contour and/or on at least one section of the sliding sleeve body directly adjoining the surface of the engagement contour, which edge layer is plastically deformed relative to the rest of the sliding sleeve body. Regardless of the method of rough machining used to manufacture the sliding sleeve body. Preferably, however, the sliding sleeve body is produced by means of cutting or powder metallurgy, in particular by turning or sintering. The edge layer is produced during a finishing step following the rough machining. In particular, no material removal takes place here. Such an edge layer is relatively dimensionally accurate and smooth. Therefore, the edge layer has only a small roughness. The interaction between the engagement contour and the shift fork cooperating with said engagement contour can thereby be achieved without wear or with low wear. This also results in a high overall efficiency of the synchronization unit provided with the sliding sleeve.

The edge layer may be cold-hardened. Thereby, the edge layer has a greater hardness than the rest of the sliding sleeve body. This further increases the wear resistance of the sliding sleeve body in the region of the engagement contour.

Preferably, the edge layer is a finishing layer. Thus, the edge layer is manufactured by finishing. The effects and advantages already explained in connection with the method according to the invention result here.

Advantageously, the joining profile is uncoated. In other words, the joining profile has no coating. The joining contour is thus of relatively simple design and can be produced simply and inexpensively.

The edge layer may have an oil supply structure. Thereby, a sufficient amount of oil can always be provided in the area of the engagement profile. In this way, wear in the region of the engagement contour and/or on the shift fork engaged on the engagement contour is also avoided. Preferably, the oil feed structure is introduced into the edge layer simultaneously by means of deformation of the edge layer.

The oil supply structure may include at least one oil pocket and/or at least one oil passage. The oil channel extends, for example, radially, axially or circumferentially with respect to the axis of rotation of the sliding sleeve. In this fuel supply configuration, a low-wear or wear-free interaction between the engagement contour and the shift fork cooperating with the engagement contour can be achieved.

According to one embodiment, the engaging profile has a substantially rectangular cross-section. This engagement profile can cooperate with a standard shift fork.

The engaging profile may have an undercut in cross-section. A particularly reliable interaction between the shift fork and the engagement contour results here. In particular, an undesired slipping out of the shift fork from the engagement contour can be effectively avoided.

Preferably, the engagement contour completely surrounds the circumference and/or is formed by a shift fork groove or by a shift fork web. The engagement contour running completely around the circumference is structurally simple. For this reason, the joining profile can be produced relatively simply and inexpensively. The shift fork groove and the shift fork web are engagement contours which have proven themselves to be reliable and which can reliably interact with a conventional shift fork.

Furthermore, the object is achieved by a synchronization unit having a sliding sleeve according to the invention and a shift fork, wherein the shift fork engages on an engagement contour. The synchronization unit operates with relatively low or no wear, since the sliding sleeve and the shift fork interact with each other with low or no wear. Furthermore, such a synchronization unit has a relatively high efficiency. Said relatively high efficiency advantageously affects the efficiency of a transmission equipped with such a synchronization unit.

Furthermore, the features, effects and advantages mentioned in connection with the method according to the invention and the sliding sleeve according to the invention also apply to the synchronization unit and vice versa.

Drawings

The invention is elucidated below on the basis of different embodiments shown in the drawings. The figures show:

fig. 1 schematically shows a side view of a synchronization unit according to the invention with a sliding sleeve according to a first mode according to the invention, which is manufactured by means of a method according to the invention;

fig. 2 shows the synchronization unit according to the invention in fig. 1 viewed in direction II;

fig. 3 shows a section III-III through the sliding sleeve of the synchronization unit in fig. 2;

fig. 4 shows a representation corresponding to fig. 3, in which the shift gate of the sliding sleeve is formed according to a variant;

fig. 5 shows a section of a sliding sleeve according to a first embodiment of the invention during the course of the method according to the invention for producing a sliding sleeve;

fig. 6 shows a further section of the sliding sleeve according to the invention from fig. 5 during the course of the method according to the invention for producing the sliding sleeve;

fig. 7 shows schematically a side view of a synchronization unit according to the invention with a sliding sleeve according to a second embodiment according to the invention, which is manufactured by means of a method according to the invention;

fig. 8 shows the synchronization unit according to the invention in fig. 7 viewed in the direction VIII;

fig. 9 shows a section IX-IX through the sliding sleeve of the synchronization unit in fig. 8;

fig. 10 shows a representation corresponding to fig. 9, in which the shift fork webs of the sliding sleeve are formed according to a variant;

fig. 11 shows a section of a sliding sleeve according to a second embodiment of the invention during the course of a method according to the invention for producing a sliding sleeve;

fig. 12 shows a further section of the sliding sleeve of fig. 11 according to the invention during the course of the method according to the invention for producing a sliding sleeve; and

fig. 13 shows schematically a detail view of a face of an engagement profile of a sliding sleeve according to the invention, which can be constructed according to a first embodiment or according to a second embodiment.

Detailed Description

Fig. 1 and 2 show a synchronization unit 10, which comprises a sliding sleeve 12 and a shift fork 14 according to a first embodiment.

The remaining components of the synchronization unit 10 are not shown for reasons of better overview.

The sliding sleeve 12 has a sliding sleeve body 16 which is rotatable about a sliding sleeve axis 18.

Furthermore, an engagement contour 19, which is completely circumferential on the circumference and which is formed in the first embodiment by a shift fork 20, is provided on the outer circumference of the sliding sleeve body 16.

The shift fork 14, more precisely the section of the shift fork 14 provided for this purpose, engages into the shift fork pocket 20.

The shift rail 20 according to the first variant of the first embodiment is shown in detail in fig. 3.

Here, the shift rail 20 has a rectangular cross section.

The shift rail 20 is delimited by a total of three surfaces 21a, 21b, 21 c.

The surface 21a is formed as a bottom 22.

The faces 21b, 21c are side walls 24, 26. Both of which extend substantially perpendicularly outwardly from the base 22.

The bottom 22 and the two side walls 24, 26 are also provided with edge layers 28, 30, 32, respectively, which are plastically deformed relative to the rest of the sliding sleeve body 16.

In the embodiment shown, all of the edge layers 28, 30, 32 are designed as finishing layers.

Furthermore, all of the edge layers 28, 30, 32 are cold-hardened. The edge layer thus has a greater hardness than the rest of the sliding sleeve body 16.

The coating is not provided on the faces 21a, 21b, 21c delimiting the shift rail 20. The shift gate 20 is therefore formed without a coating.

Fig. 4 shows a sliding sleeve 12 with a shift gate 20 according to a second variant of the first embodiment.

The sliding sleeve differs from the variant according to fig. 3 only in that the side wall 24 has undercuts 34 which act in the radial direction.

Furthermore, the embodiment of fig. 3 is also suitable for the shift rail 20 according to fig. 4.

In the shift rail 20 according to fig. 3 and in the shift rail according to fig. 4, the bottom 22 is provided with an oil supply 36 (see fig. 13). The oil supply structure is characterized by a specifically produced recess.

The oil feed 36 has a first oil passage 38 that extends substantially along the sliding sleeve axis 18.

Furthermore, a total of three

further oil channels

40, 42, 44 are provided, which each extend substantially in the circumferential direction with respect to the sliding sleeve axis 18.

The sliding sleeve 12 can be manufactured as follows.

The sliding sleeve body 16 is first produced in the region of rough machining by means of a cutting method, for example turning, or a powder metallurgy method, for example sintering. Here too, a shift rail 20 is formed.

In this way, the surfaces 21a, 21b, 21c and thus the side walls 24, 26 and the base 22 of the shift fork 20 are plastically deformed by means of a finishing process. The material of the sliding sleeve body 16 present there is plasticized and caused to flow, so that roughness peaks and roughness valleys are flattened on the surfaces 21a, 21b, 21 c.

In the first embodiment, the entire bottom 22 and the entire sidewalls 24, 26 are finished.

The finished section is also cold-hardened during finishing in the form of the edge layers 28, 30, 32.

Furthermore, an oil feed structure 36 is introduced into the bottom 22 during and by finishing (see also fig. 13).

The deformation of the side wall 24 is exemplarily shown in fig. 5.

The finishing takes place here by means of a finishing roller 46, which is fixed on an associated carrying structure 48.

The finishing of the bottom 22 is shown in fig. 6 for one section of the bottom. Here too, a finishing roller 46 is used, which is fixed on an associated carrying structure 48.

It goes without saying that, with the aid of the method shown, only sections of the surfaces 21a, 21b, 21c can be finished, so that the edge layers 28, 30, 32 with the associated properties are obtained only in these sections.

Fig. 7 and 8 show a synchronization unit 10, which comprises a sliding sleeve 12 according to a second embodiment and a shift fork 14. Here, only the differences from the first embodiment will be discussed below. Identical or mutually corresponding components are provided with the same reference numerals.

The parts of the synchronization unit 10 that project beyond the sliding sleeve 12 and the shift fork 14 are not shown again for reasons of better overview.

The circumferentially completely circumferential engagement contour 19 on the outer circumference of the sliding sleeve body 16 is now formed by the shift fork web 50.

The shift fork web interacts with the shift fork 14 via a groove provided on the shift fork 14. In other words, at least one section of the shift fork 14 surrounds the shift fork web 50.

A shift fork web 50 according to a first variant of the second embodiment is shown in detail in fig. 9.

Here, the shift fork web 50 has a rectangular cross section.

The rectangular cross-section is bounded by a total of three

faces

52a, 52b, 52 c.

Here, the surface 52a is configured as a covering surface 54.

Faces

52b, 52c are sidewalls 56, 58. Both of which extend substantially perpendicularly radially inwardly from the cover surface 54.

Axially on both sides, directly adjacent to the shift fork web 50, a

surface

60a, 60b of the sliding sleeve body 16 is provided.

The covering surface 54 and the two

side walls

56, 58 are each provided with an

edge layer

62, 64, 66 which is plastically deformed relative to the rest of the sliding sleeve body 16.

A section of the face 60a is also provided with an edge layer 68a which is plastically deformed relative to the rest of the sliding sleeve body. The same applies to a section of the face 60b which is provided with an edge layer 68 b.

In the embodiment shown, all of the edge layers 62, 64, 66, 68a, 68b are designed as finishing layers.

Furthermore, all edge layers 62, 64, 66, 68a, 68b are cold-work hardened. The edge layer thus has a greater hardness than the rest of the sliding sleeve body 16.

The coating is not provided on the

surfaces

52a, 52b, 52c delimiting the shift fork web 50. Likewise, fewer coatings are provided on the

faces

60a, 60 b.

The sliding sleeve 12 and in particular the shift fork web 50 are therefore designed without a coating.

Fig. 10 shows a sliding sleeve 12 with a shift fork web 50 according to a second variant of the first embodiment.

The sliding sleeve differs from the variant according to fig. 9 only in that the side wall 56 has an undercut 34 which acts in the radial direction.

Furthermore, the embodiment of fig. 9 is also suitable for the shift fork web 50 according to fig. 10.

In the shift fork web 50 according to fig. 9 and in the shift fork web 50 according to fig. 10, the

side walls

56, 58 and the sections of the adjoining

faces

60a, 60b are provided with an oil supply 36 (see fig. 13). The explanation of the oil supply structure 36 is also applicable to the second embodiment in the same manner as in the first embodiment.

The sliding sleeve 12 according to the second embodiment can be manufactured similarly to the sliding sleeve according to the first embodiment. Only the shift fork webs 50 are produced instead of the shift fork grooves and are finished by means of a finishing process (see fig. 11 and 12). Accordingly, the foregoing description applies in a similar manner.

In addition, the

surfaces

60a, 60b are machined by means of a finishing process in the sliding sleeve according to the second embodiment.

This results in the edge layers 62, 64, 66, 68a, 68 b.

Claims

1. Method for producing a sliding sleeve (12) for a synchronization unit (10), having the following steps:

a) producing a sliding sleeve body (16) by means of cutting or powder metallurgy, wherein the sliding sleeve body (16) has an engagement contour (19) for a shift fork (14), and then

b) At least one section of a surface (21a, 21b, 21c, 52a, 52b, 52c) of the engagement contour (19) that delimits the engagement contour (19) and/or at least one section of a surface (60a, 60b) of the sliding sleeve body (16) that directly adjoins the engagement contour (19) is plastically deformed.

2. The method of claim 1, wherein the plastic deformation is performed by finishing.

3. Method according to claim 1 or 2, characterized in that the oil feed structure (36) is shaped into the finished section during and by finishing.

4. The method of any of the preceding claims, wherein the finished section is cold work hardened during finishing.

5. Method according to one of the preceding claims, characterized in that the engagement contour (19) is formed by a shift rail (20), in particular wherein the entire bottom (22) and/or the entire side walls (24, 26) of the shift rail (20) are plastically deformed.

6. Method according to one of claims 1 to 4, characterized in that the engagement contour (19) is formed by a shift fork web (50), in particular wherein the entire cover surface (54) of the shift fork web (50), the entire side walls (56, 58) of the shift fork web (50) and/or a surface (60a, 60b) of the sliding sleeve body (16) directly adjoining the shift fork web (50) is plastically deformed.

7. A sliding sleeve (12) for a synchronization unit (10) has a sliding sleeve body (16), an engagement contour (19) for a shift fork (14) is provided on the sliding sleeve body, said engagement contour being designed to interact with a section of the shift fork (14), characterized in that the sliding sleeve body (16) has an edge layer (28, 30, 32, 62, 64, 66, 68a, 68b) on at least one section of a surface (21a, 21b, 21c, 52a, 52b, 52c) of the engagement contour (19) which delimits the engagement contour (19) and/or on at least one section of a surface (60a, 60b) of the sliding sleeve body (16) which directly adjoins the engagement contour (19), the edge layer is plastically deformed relative to the rest of the sliding sleeve body (16).

8. The sliding sleeve (12) of claim 7 wherein said edge layer (28, 30, 32, 62, 64, 66, 68a, 68b) is cold-hardened.

9. The sliding sleeve (12) according to claim 7 or 8, characterised in that the edge layer (28, 30, 32, 62, 64, 66, 68a, 68b) is a finishing layer.

10. The sliding sleeve (12) as claimed in one of claims 7 to 9, characterized in that the engagement contour (19) is uncoated.

11. The sliding sleeve (12) according to one of claims 7 to 10, wherein the edge layer (28, 30, 32, 62, 64, 66, 68a, 68b) has an oil supply structure (36), in particular wherein the oil supply structure (36) comprises at least one oil pocket and/or at least one oil channel (38, 40, 42, 44).

12. The sliding sleeve (12) as claimed in one of claims 7 to 11, characterised in that the engagement profile (19) has a substantially rectangular cross section.

13. The sliding sleeve (12) as claimed in one of claims 7 to 12, characterized in that the cross section of the engagement contour (19) has an undercut (34).

14. Sliding sleeve (12) according to one of claims 7 to 13, characterised in that the engagement contour (19) completely surrounds on the circumference and/or the engagement contour (19) is formed by a shift fork groove (20) or by a shift fork tab (50).

15. Synchronization unit (10) with a sliding sleeve (12) according to one of claims 7 to 14 and a shift fork (14), wherein the shift fork (14) engages on the engagement profile (19).