CN111173913A

CN111173913A - Torque converter, drive train and motor vehicle comprising same, and method for manufacturing same

Info

Publication number: CN111173913A
Application number: CN201811346144.7A
Authority: CN
Inventors: 孙艳霞; 胡勋; 应学军
Original assignee: Faroeco Torque Converter Nanjing Co Ltd
Current assignee: Faroeco Torque Converter Nanjing Co Ltd
Priority date: 2018-11-13
Filing date: 2018-11-13
Publication date: 2020-05-19

Abstract

The invention discloses a torque converter for a motor vehicle, comprising: a pump impeller and a turbine driven by the pump impeller; and a cover attached to the pump wheel and driven by a driving part of an engine side, wherein the cover has a cover connection block through which the cover is fixed to the driving part and rotates together with the driving part, wherein the cover connection block has at least an end section configured to contact the cover and having a circular cross section. The invention also proposes a powertrain for a motor vehicle and a motor vehicle comprising the above-mentioned torque converter, and a method for manufacturing the above-mentioned torque converter.

Description

Torque converter, drive train and motor vehicle comprising same, and method for manufacturing same

Technical Field

The present invention relates to a torque converter for a motor vehicle, and more particularly, to a torque converter having a cylindrical cover connection block, and a power train and a motor vehicle including the same, and a method of manufacturing the torque converter.

Background

Typically, torque converters are present in automatically shifting motor vehicles. The torque converter is installed between an engine and a transmission, and functions to transmit torque, convert torque, shift speed, and engage and disengage using fluid (usually oil) as a working medium. Torque converters generally include: a pump impeller and a turbine driven by the pump impeller; and a cover attached to the pump impeller and driven by a driving member on an engine side. The cover has a cover connection block through which the cover is fixed to and rotates together with the drive member, thereby transmitting torque from the drive member on the engine side to the torque converter.

In prior designs, the cover connection block on the cover of the torque converter typically has a complex shape, typically in the shape of a stepped block, mostly a casting, and is typically welded to the cover using reactive gas shielded arc welding. The cover is connected by a casting with a complex shape, so the manufacturing cost is high and the construction period is long. Further, since welding is performed by reactive gas shielded arc welding, the requirement for the joining process conditions is high, and an additional welding material is required, which is expensive. Therefore, there is a need for a torque converter in which a cover attachment block on a cover is simple in shape and easy to manufacture, and a method of attaching the cover attachment block to the cover is inexpensive and easy to operate, while securing the strength of the attachment.

Disclosure of Invention

The object of the present invention is to provide a torque converter for a motor vehicle comprising: a pump impeller and a turbine driven by the pump impeller; and a cover attached to the pump wheel and driven by a driving part of an engine side, wherein the cover has a cover connection block through which the cover is fixed to the driving part and rotates together with the driving part, wherein the cover connection block has at least an end section configured to contact the cover and having a circular cross section.

Since the cover connection block has a cylindrical end section, the cover connection block can be fixed to the cover by friction welding, so that an operationally simple and inexpensive connection is achieved. Compared with active gas shielded arc welding, friction welding is cheaper and has simple process; compared with a press fit assembly process, the friction welding operation is simpler.

The torque converter according to the invention may have one or more of the following features, alone or in combination.

According to one embodiment of the invention, the cap connection block is fixed to the cap by friction welding.

According to one embodiment of the present invention, the cap connection block has an overall shape of a cylinder. Thus, the shape is simple and easy to process, and the connection can be performed by using a simple and cheap friction welding process.

According to one embodiment of the invention, the cap connector block has an inner recess at a root of the cap connector block.

According to one embodiment of the invention, the cap connection block has a threaded hole and the cap has a cap recess coaxial with the threaded hole and having a diameter slightly smaller than the diameter of the internal recess in the cap connection block and slightly larger than the nominal diameter of the threaded hole.

The presence of the inner concave portion of the cap connection block and the cap concave portion of the cap makes friction welding easier to perform, and unnecessary material can be filled into the concave portion at the time of friction welding without affecting the thread of the threaded hole of the cap connection block, thereby not affecting the connection of the cap connection block and the drive member on the engine side.

According to one embodiment of the invention, 3, 4 or 6 cap connection blocks are angularly evenly arranged on the cap.

According to one embodiment of the invention, the cap connection block is made of SCM420H or 20 CrMo.

According to one embodiment of the invention, the cap connection block is made of seamless steel tubing. Therefore, the material is cheap and the processing is simple.

According to one embodiment of the invention, the weld at the outer surface of the cap connection block is machined. The slag on the surface of the cover connecting block is removed by machining, so that the appearance is good and stress concentration is avoided.

According to one embodiment of the invention, after said machining, said cap connection block has an external recess at the root of said cap connection block.

The invention also provides a power train for a motor vehicle and the motor vehicle comprising the torque converter.

The present invention also proposes a method for manufacturing a torque converter comprising: a pump impeller and a turbine driven by the pump impeller; a cover attached to the pump impeller and driven by an engine-side driving member, wherein the method includes: providing a cap connecting block having at least an end section configured to contact the cap and having a circular cross-section; the cap connecting block is fixed to the cap by friction welding so that the cap can be fixed to and rotated with the driving member through the cap connecting block.

The torque converter manufactured by the above method is simple and inexpensive to operate because the end section of the cover connection block on the cover of the torque converter is cylindrical and can be connected by friction welding. Compared with active gas shielded arc welding, the friction welding process is simple, and extra welding materials are not needed, so that the friction welding process is cheaper; compared with a press fit assembly process, the friction welding operation is simpler.

The method of manufacturing a torque converter according to the invention may have one or more of the following features, alone or in combination.

According to one embodiment of the present invention, the cap connection block has an overall shape of a cylinder. So that the shape is simple and easy to process.

According to one embodiment of the invention, the method comprises machining a weld at an outer surface of the cap connection block after friction welding. The slag on the surface of the cover connecting block is removed by machining, so that the appearance is good and stress concentration is avoided.

According to one embodiment of the invention, the method further comprises forming an indent at the root of the cap connection block prior to friction welding.

According to an embodiment of the invention, the method further comprises forming an outer recess at a root of the cap connection block after machining.

According to an embodiment of the invention, the method further comprises: prior to friction welding, forming a threaded bore in the cap connection block and forming a cap recess on the cap coaxial with the threaded bore and having a diameter slightly less than the diameter of the internal recess in the cap connection block and slightly greater than the nominal diameter of the threaded bore.

Forming the inner concave portion of the cap link block and the cap concave portion of the cap makes friction welding easier to perform, and excessive material can be filled into the concave portion at the time of friction welding without affecting the thread of the threaded hole of the cap link block, thereby not affecting the connection of the cap link block and the driving member on the engine side.

According to one embodiment of the invention, in the method, 3, 4 or 6 cap connection blocks are angularly fixed evenly to the cap.

According to one embodiment of the invention, in the method, the cap connection block is made of SCM420H or 20 CrMo.

According to one embodiment of the invention, in the method, the cap connection block is made of seamless steel tubing. Therefore, the material is cheap and the processing is simple.

The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the present teachings when taken in connection with the accompanying drawings.

Drawings

FIG. 1 is a perspective view of a torque converter according to the present invention.

FIG. 2 is a perspective view of a cover of a torque converter according to the present invention.

FIG. 3 is a partial cross-sectional view of a cover of a torque converter according to the present invention.

Fig. 4 is a perspective view of a cover connection block of a cover of a torque converter according to the present invention.

FIG. 5 is a finite element simulation model diagram of a portion of a cover and a portion of a drive component of a torque converter according to the present invention.

FIG. 6 is a cross-sectional simulated model view of a cover of a torque converter according to the present invention.

Fig. 7 is a graph of a simulation result of stress distribution of a cover of a torque converter according to the present invention at an oil pressure of 1000Nm driving torque of 0.4 Mpa.

Fig. 8 is a graph of a simulation result of stress distribution of a cover of a torque converter according to the present invention at an oil pressure of 1000Nm drag torque of 0.4 Mpa.

In the various figures, equivalent elements are denoted by the same reference numerals.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view of a torque converter 1 according to the present invention. The torque converter 1 includes: a pump impeller 2 and a turbine wheel (not shown) driven by the pump impeller 2; and a cover 3 attached to the pump impeller 2 and driven by an engine-side driving member (not shown). Wherein the cover 3 has a cover connection block 4, by which the cover 3 is fixed to the driving part and rotates together with the driving part. According to the orientation shown in fig. 1, the engine is located on the right side of the torque converter 1, and the cover connection block 4 faces the drive member on the engine side and is configured to be connected with the drive member.

Fig. 2 is a perspective view of the cover 3 of the torque converter 1 according to the present invention. Fig. 3 is a partial sectional view of the cover 3 of the torque converter 1 according to the present invention. Fig. 4 is a perspective view of a cover connection block 4 of the cover 3 of the torque converter 1 according to the present invention.

As can be seen from fig. 1 to 4, the cap connector block 4 optionally has a cylindrical shape. The cover link block 4 of the torque converter according to the present invention is simple in shape and easy to manufacture, compared to the cover link block of the conventional torque converter. As shown more clearly in fig. 3 and 4, the cover attachment block 4 has a threaded hole 43, and the circumferential wall of the threaded hole 43 has threads 44 for engagement with an engine-side drive member to transmit torque from the drive member to the torque converter 1.

Since the cap connection block 4 has a cylindrical shape and the screw hole 43 is a through hole, the cap connection block 4 may be made of a seamless steel pipe. In this way, the cap connecting block 4 can be made by simply cutting a seamless steel pipe, and is inexpensive in material and simple in processing.

It should be noted that the cap joint block 4 having a cylindrical shape is only one embodiment of the present disclosure, and the cap joint block 4 may have other shapes. In particular, the cap connection block 4 has at least an end section configured to contact the cap 3 and having a circular cross section. That is, as long as the end section for the contact cover 3 is cylindrical, the other end opposite to the end section for the contact cover 3 may have any shape, for example, the other end may be rectangular, oval, irregular, or the like, and the size of the other end is also not limited, and may be greater than or less than or equal to the size of the end section for the contact cover 3.

Preferably, as shown in fig. 1 to 4, the overall shape of the cap connection block 4 is cylindrical.

Since the end section of the cover connection block 4 of the torque converter 1 according to the present invention is cylindrical, it can be fixed to the cover 3 by friction welding. The friction welding is performed by using heat generated by friction of a contact surface of a workpiece as a heat source to cause plastic deformation of the workpiece under the action of pressure. In order to generate friction, the work piece to be welded needs to be rotated at high speed. In the present invention, the end section of the cap connecting piece 4 is designed cylindrically, that is, the end section of the cap connecting piece 4 is symmetrical with respect to its axis center, so that friction welding can be used thereto. Preferably, the cap attaching block 4 is cylindrical as a whole, and then it is symmetrical as a whole with respect to the center of its axis, making it easier to perform friction welding. The friction welding is low in cost because brazing filler metal is not needed in the friction welding, the process is simple and the like. Compared with active gas shielded arc welding, friction welding is cheaper and has simple process; compared with a press fit assembly process, the friction welding operation is simpler.

According to a preferred embodiment of the invention, the cap connection block 4 is made of SCM420H or 20 CrMo. And because the cover 3 of the torque converter 1 is made of SAPH 440. The connection between the cap connection block 4 and the cap 3 is adapted to use friction welding. Friction welding has been used in the impeller 2 of the torque converter, the casing of the impeller 2 is made of SAPH440, and the hub connected to the impeller 2 is made of SCM420H or 20CrMo, and the hub is fixed to the casing of the impeller 2 using friction welding. Since the material of the cover link block 4 is the same as that of the hub and the material of the cover 3 of the torque converter 1 is the same as that of the housing of the pump impeller 2, it can be confirmed that the connection between the cover link block 4 and the cover 3 can use friction welding in terms of material.

According to a preferred embodiment of the invention, as shown in fig. 3, the cap connector block 4 has an internal recess 41 at the root of the cap connector block 4. In this way, excessive material or slag at the time of friction welding can be filled into the inner concave portion 41 without affecting the threads 44 of the threaded hole 43 of the head connector block 4, and thus without affecting the connection of the head connector block 4 and the engine-side drive member.

According to a preferred embodiment of the present invention, as shown in fig. 3, the cap 3 has a cap recess 31, the cap recess 31 is coaxial with the threaded hole 43, and the diameter of the cap recess 31 is slightly smaller than the diameter of the inner recess 41 of the cap connector block 4 and slightly larger than the nominal diameter of the threaded hole 44. The reason why the diameter of the cap recess 31 is set larger than that of the screw hole 43 here is that excess material or slag can be filled into the cap recess 31 at the time of friction welding, so that friction welding is easier to perform and no interference with the engine drive component is ensured. The reason for setting the diameter of the cap recess 31 to be "slightly" larger than the diameter of the threaded hole 44 and slightly smaller than the diameter of the inner recess of the cap attaching block is to ensure firm engagement between the cap 3 and the cap attaching block 4. If the diameter of the cap recess 31 is much larger than the diameter of the screw hole 44, the contact area between the cap 3 and the cap connection block 4 is small, and it is difficult to secure firm engagement.

As shown in fig. 1 and 2, three cover connection blocks 4 are angularly uniformly provided on the cover 3. This is not essential, however, but it is also possible to arrange four or six cover connection blocks angularly uniformly on the cover 3, depending on the state of the interface with the drive element on the engine side.

The cylindrical diameter of the cover connection piece 4 or the diameter of the end section of the cover connection piece 4 is also not fixed, depending on the torque to be transmitted, the size of the torque converter 1 or the cover 3, etc.

According to a preferred embodiment of the invention, the weld at the outer surface of the lid connection block 4 is machined. That is, the weld bead, i.e., the slag, at the outer surface of the cap connection block 4 may be removed by machining or the like. Machining the weld at the outer surface of the cap connecting block 4 may avoid stress concentrations, since the presence of slag may cause instability or cause stress concentrations. Further, it is possible to give the cap attaching block 4 a good appearance.

According to a preferred embodiment of the present invention, as shown in fig. 3, the cap connection block 4 has an outer recess 42 at the root of the cap connection block 4. This is due to the machining after the friction welding.

The powertrain for a motor vehicle according to the invention comprises a torque converter 1 according to the invention.

The motor vehicle according to the invention comprises a torque converter 1 according to the invention.

The invention also proposes a method for manufacturing a torque converter 1 comprising: a pump impeller 2 and a turbine driven by the pump impeller 2; a cover 3 attached to the pump impeller 2 and driven by an engine-side driving member. The method according to the invention comprises the following steps: providing a cap connecting block 4, said cap connecting block 4 having at least an end section configured to contact said cap 3 and having a circular cross section; the cap connector block 4 is fixed to the cap 3 by friction welding so that the cap 3 can be fixed to and rotated with the driving member through the cap connector block 4.

The torque converter 1 manufactured by the method according to the present invention is simple and inexpensive to operate because the end section of the cover joint block 4 on the cover 3 of the torque converter 1 is cylindrical and can be connected by friction welding. Compared with active gas shielded arc welding, friction welding is cheaper and has simple process; compared with a press fit assembly process, the friction welding operation is simpler.

According to the preferred embodiment of the present invention, the cap connection block 4 has a cylindrical overall shape, as shown in fig. 1 to 4. So that the shape is simple and easy to process.

According to a preferred embodiment of the present invention, the method of manufacturing the torque converter 1 according to the present invention further includes forming an inner recess 41 at a root portion of the cover joint block 4 before friction welding. In this way, excessive material or slag at the time of friction welding can be filled into the inner concave portion 41 without affecting the threads 44 of the threaded hole 43 of the head connector block 4, and thus without affecting the connection of the head connector block 4 and the engine-side drive member.

According to a preferred embodiment of the present invention, the method of manufacturing the torque converter 1 according to the present invention further includes: before friction welding, a threaded hole 43 is formed in the cap connecting block 4 and a threaded hole 43 coaxial with the threaded hole 43 and having a diameter slightly smaller than the diameter of the inner recess 41 of the cap connecting block 4 and slightly larger than the nominal diameter of the threaded hole 44 is formed in the cap 3. Excess material or slag may be filled into the cap recess 31 at the time of friction welding, so that friction welding is more easily performed.

According to a preferred embodiment of the present invention, the method of manufacturing the torque converter 1 according to the present invention further includes machining a weld at an outer surface of the cover connection block after the friction welding. The weld at the outer surface of the cap connecting block 4 is processed to avoid stress concentration. Further, it is possible to give the cap attaching block 4 a good appearance.

According to a preferred embodiment of the present invention, the method of manufacturing the torque converter 1 according to the present invention further includes forming an outer recess 42 at a root portion of the cover connection piece 4 after machining. This is due to the machining after the friction welding.

According to a preferred embodiment of the invention, the method of manufacturing the torque converter 1 according to the invention may also comprise other features described above in relation to the torque converter 1 according to the invention, which will not be described in detail here.

In the following, it is further explained by a series of simulation results that the connection of the cylindrical cap connecting block 4 to the cap 3 by friction welding can have sufficient strength.

Fig. 5 is a finite element simulation model diagram of a part of the cover 3 of the torque converter 1 and a part of the driving part according to the present invention. Fig. 5 shows a 120-degree symmetrical model of the cover 3 and the drive part 5 of the torque converter 1 according to the invention, wherein the three cover connection pieces 4 fixed to the cover 3 are hidden. The three arrows on fig. 5 indicate that a total torque of 1000Nm is applied to the drive member 3. Further, an oil pressure of 400kPa is applied to the entire surface of the cover 3.

Fig. 6 is a cross-sectional simulated model diagram of the cover 3 of the torque converter 1 according to the present invention. Fig. 6 shows a cross-sectional model after friction welding with the cap joint block 4. Wherein, after the friction welding, the weld of the outer surface of the cap connection block 4 is processed, and the welding heat affected zone has a hardness of 30 HRC.

Fig. 7 is a graph of a simulation result of stress distribution of the cover 3 of the torque converter 1 according to the present invention at an oil pressure of 1000Nm driving torque of 0.4 Mpa. Fig. 7 shows that the maximum value of von mises stress at the first region 61 of the root of the cap connection block 4 is about 382Mpa with an applied drive torque of 1000 Nm.

Fig. 8 is a graph of the simulation result of the stress distribution of the cover 3 of the torque converter 1 according to the present invention at a hydraulic pressure of 1000Nm drag torque of 0.4 Mpa. Fig. 8 shows that the maximum value of von mises stress at the second region 62 of the root of the cap connection block 4 is about-212 Mpa with an applied drag torque of 1000 Nm.

According to the above results, the equivalent stress amplitude was 298Mpa, which is smaller than the material fatigue strength at the weld. Therefore, the friction welding has durability.

While the best modes for carrying out the many aspects of the present teachings have been described in detail, those familiar with the art to which these teachings relate will recognize various alternative aspects for practicing the present teachings that are within the scope of the appended claims.

Claims

1. A torque converter for a motor vehicle, comprising:

a pump impeller and a turbine driven by the pump impeller; and

a cover attached to the pump impeller and driven by a driving part on an engine side, wherein the cover has a cover connection block through which the cover is fixed to the driving part and rotates together with the driving part,

wherein the cap connecting block has at least an end section configured to contact the cap and having a circular cross-section.

2. The torque converter of claim 1, wherein the cover connection block is secured to the cover by friction welding.

3. The torque converter of claim 2, wherein the cover connection block has an overall shape of a cylinder.

4. The torque converter of claim 2, wherein the cover connector block has an internal recess at a root of the cover connector block.

5. The torque converter of claim 4, wherein the cover connection block has a threaded bore and the cover has a cover recess that is coaxial with the threaded bore and has a diameter that is slightly smaller than a diameter of an internal recess in the cover connection block and slightly larger than a nominal diameter of the threaded bore.

6. The torque converter of any of claims 1-5, wherein 3, 4, or 6 cover connection blocks are angularly evenly arranged on the cover.

7. The torque converter of any of claims 1-5, wherein the cover connection block is made from SCM420H or 20 CrMo.

8. The torque converter of any one of claims 1-5, wherein the cover connection block is made of seamless steel tubing.

9. The torque converter of any of claims 1-5, wherein a weld at an outer surface of the cover connection block is machined.

10. The torque converter of claim 9, wherein the cover connection block has an outer recess at a root of the cover connection block after the machining.

11. A powertrain for a motor vehicle comprising a torque converter according to any one of claims 1-10.

12. A motor vehicle comprising a torque converter according to any one of claims 1-10.

13. A method for manufacturing a torque converter, the torque converter comprising: a pump impeller and a turbine driven by the pump impeller; a cover attached to the pump impeller and driven by an engine-side driving member,

wherein, the method comprises the following steps:

providing a cap connecting block having at least an end section configured to contact the cap and having a circular cross-section;

the cap connecting block is fixed to the cap by friction welding so that the cap can be fixed to and rotated with the driving member through the cap connecting block.

14. The method of claim 13, wherein the cap connection block has an overall shape of a cylinder.

15. The method of claim 13, further comprising machining a weld at an outer surface of the cap connection block after friction welding.

16. The method of claim 15, further comprising forming an external recess at a root of the cap connection block after machining.

17. The method of any of claims 13-16, further comprising forming an indent at a root of the cap connection block prior to friction welding.

18. The method of claim 17, further comprising: prior to friction welding, forming a threaded bore in the cap connection block and forming a cap recess on the cap coaxial with the threaded bore and having a diameter slightly less than the diameter of the internal recess in the cap connection block and slightly greater than the nominal diameter of the threaded bore.

19. The method of any of claims 13-15, wherein 3, 4, or 6 cap connection blocks are angularly uniformly secured to the cap.

20. The method according to any of claims 13-15, wherein the lid connection block is made of SCM420H or 20 CrMo.

21. The method of any of claims 13-15, wherein the cap connection block is made of seamless steel tubing.