WO2020051873A1

WO2020051873A1 - Pilot assembly, processing method of pilot assembly and hydraulic torque converter

Info

Publication number: WO2020051873A1
Application number: PCT/CN2018/105704
Authority: WO
Inventors: Joshua David Cerreta
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2018-09-14
Filing date: 2018-09-14
Publication date: 2020-03-19
Also published as: CN112424505A

Abstract

A pilot assembly, a processing method of the pilot assembly and a hydraulic torque converter. The pilot assembly is used for a hydraulic torque converter, and comprises a cover(111) and a sleeve(2). The cover includes a protrusion(1111) and the sleeve can be attached on the outer periphery of the protrusion. The protrusion includes a pilot boss of a first size, and in an assembled condition that the sleeve is attached on the protrusion, the sleeve forms a pilot boss of a second size. The pilot assembly is of low cost, capable of applying to multiple types of hydraulic torque converters, and adapted to modular production.

Description

PILOT ASSEMBLY, PROCESSING METHOD OF PILOT ASSEMBLY AND HYDRAULIC TORQUE CONVERTER

TECHNICAL FIELD

The present disclosure relates to the technical field of transmission, more specifically to a pilot for a transmission, and in particular to a pilot for a hydraulic torque converter.

BACKGROUND

Figure 1 is a partial cross sectional view of a known hydraulic torque converter connected to an engine. A pilot boss 102 is welded to one end face of a hydraulic torque converter cover 101 via weld 103. The pilot boss 102 helps align between a connection on the cover 101 and a crankshaft of the engine.

The method of producing the pilot boss 102 and securing it to the cover 101 via welding mainly comprises: forging a pilot blank, machining the pilot blank to specific size to form the pilot boss 102, welding the pilot boss 102 to the cover 101, and machining the pilot boss 102 to compensate for the distortion caused by the welding process. Welding provides a precondition for modularity of the pilot, in other words, pilot bosses 102 with different sizes can be welded to the cover 101 according to different installation environments. However, forging the pilot blank and the multiple machining operations are still not cost effective.

Another method to form the pilot is to stamp the pilot in one piece with the cover. Stamping is a cost effective option to form pilots of the same size. However, since one set of stamping die only fits pilots of the same size, stamping is not good for modularity of pilots with different sizes.

U.S. Patent No. 7997072B2 discloses a method that first stamping a hydraulic torque converter cover, then welding a pilot boss to the cover. U.S. Patent No. 7841174B2 discloses a method that press fitting a pilot boss to a hydraulic torque converter cover with a protrusion. In these two methods, although modularity of pilots with different sizes is considered, the hydraulic torque converter cover is treated as a part to secure the pilot boss, which means that, for pilots of different sizes, the same number of pilot bosses with different sizes is needed as well. For example, for N types of pilots of different sizes, N types of pilot bosses are needed. Thus, there is a need for a low cost and simplified method to provide pilots with different sizes.

SUMMARY

The object of the present disclosure is to overcome or at least alleviate the above-mentioned shortcomings in the prior art, and to provide a pilot assembly of low cost, capable of applying to multiple types of hydraulic torque converters, and adapted to modular production.

According to a first aspect of the present disclosure, there is provided a pilot assembly, which is used for a hydraulic torque converter, and comprises a cover and a sleeve, wherein the cover includes a protrusion and the sleeve can be attached on the outer periphery of the protrusion,

wherein the protrusion includes a pilot boss of a first size, and

in an assembled condition that the sleeve is attached on the protrusion, the sleeve forms a pilot boss of a second size.

In at least one embodiment, the inner diameter of the sleeve is smaller than the outer diameter of the protrusion.

In at least one embodiment, the sleeve is mounted on the protrusion by a press force applied thereon in an axial direction.

In at least one embodiment, the axial length of the sleeve is greater than the wall thickness of the sleeve in a radial direction.

In at least one embodiment, the cover is an integrally formed part.

In at least one embodiment, the cover is a metal stamped part.

In at least one embodiment, the sleeve is an optional sleeve from a plurality of alternative sleeves of different outer diameters.

According to a second aspect of the present disclosure, there is provided a processing method of the pilot assembly, comprising:

providing the cover, wherein the cover is obtained by stamping a metal blank;

providing the sleeve, wherein the inner diameter of the sleeve is smaller than the outer diameter of the protrusion, and the outer diameter of the sleeve is greater than the outer diameter of the protrusion; and

giving a press force to the sleeve in an axial direction, thereby mounting the sleeve on the protrusion in the form of interference fit.

In at least one embodiment, the processing method further comprises machining the sleeve to a certain size to form a pilot boss of a specific size.

According to a third aspect of the present disclosure, there is provided a hydraulic torque converter, comprising the pilot assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a known hydraulic torque converter connected to an engine.

FIG. 2 is a half cross sectional view of a hydraulic torque converter with a pilot assembly according to an embodiment of the present disclosure.

DESCRIPTION OF REFERENCE SIGNS

101, 111: cover

102: pilot boss

103: weld

1111: protrusion

2: sleeve

A: axial direction

D: radial direction

DETAILED DESCRIPTION

Exemplary embodiments of the present disclosure will be described below with reference to the drawings. It should be understood that these specific descriptions are only intended to teach those skilled in the art how to practice the present disclosure, and are not intended to be exhaustive of all possible ways of carrying out the present disclosure or to limit the scope of the present disclosure.

FIG. 2 shows a half cross sectional view of a hydraulic torque converter with a pilot assembly according to an embodiment of the present disclosure. Unless defined otherwise, the adjective “axial” is with respect to a direction parallel to arrow A, the adjective “radial” is with respect to a direction parallel to arrow D.

The hydraulic torque converter has a cover 111 which is a metal stamped part. In the center of the cover 111, a protrusion 1111 extends axially outward in the axial direction A of the hydraulic torque converter. By extending axially outward, it means protrusion 1111 extends toward the engine side in a mounted state. Protrusion 1111 is generally cylindrical in shape. Protrusion 1111 is used to be affixed to a sleeve 2 which will be introduced later. Protrusion 1111 can also work as a pilot with a first size, e.g., the stamping protrusion 1111 has a proper shape which fits to connect to one type of engine crankshaft, thereby working as a pilot. The stamping procedure to make the protrusion 1111 results a low cost of the cover 111 with the protrusion 1111.

To provide pilots which can fit different types of hydraulic torque converters, in this embodiment, the sleeve 2 is introduced. Preferably, the inner diameter of the sleeve 2 is a little bit smaller than the outer diameter of the protrusion 1111, by giving the sleeve 2 a press force axially inward along the axial direction A of the hydraulic torque converter, the sleeve 2 can be affixed to the protrusion 1111 in the form of interference fit. The assembled sleeve 2 and cover 111 can be called as an assembled pilot assembly. Furthermore, since the protrusion 1111 can act as the pilot of the smallest size, the cover 111 itself including the protrusion 1111 can also be called as a pilot assembly. The outer diameter of the sleeve 2 is greater than the outer diameter of the protrusion 1111, thereby the assembled sleeve 2 works as a pilot with a second size, which is different from the pilot with the first size and can be connected to another type of engine crankshaft.

As described above, by alternatively using a sleeve 2, the hydraulic torque converter can fit to two different types of engine crankshafts. Furthermore, two methods will be introduced to ensure a hydraulic torque converter to fit more types of different engine crankshafts.

The first method includes machining the sleeve 2 which has been assembled to the protrusion 1111 to a proper size, so as to form a pilot of a certain size.

The second method includes providing a series of sleeves 2 of different diameters, then according to the assembling requirement in the production line, choosing a sleeve 2 with a proper size and pressing it to the protrusion 1111, so as to form a pilot of a certain size.

Thus, by providing N-1 types of sleeves 2 with different outer diameters, plus the protrusion 1111 which can act as the pilot with the smallest size, the present disclosure provides a series of pilot assemblies for a production line which requires N types of pilots.

Apart from the flexible sizes of the pilot assemblies in their radial direction, the pilot assemblies including the sleeves 2 have another advantage in a further aspect.

In a preferred embodiment, the axial length of the sleeve 2 is greater than its wall thickness in the radial direction D. The tubular shape of the sleeve 2 makes it easy to be produced, as to several sleeves 2 of the same size in the radial direction D (including the inner diameter and the outer diameter) , they can be cut from a long sleeve. Preferably, these several sleeves 2 with the same size in the radial direction D can have different axial lengths, thereby fitting different assembling requirements. Alternatively, the sleeves 2 can be machined again after assembling, thereby, making the pilot assembly including the sleeve 2 fitting different assembling requirements in the axial direction A.

In the present disclosure, a pilot of certain size means a pilot of certain outer diameter and certain length in the axial direction A.

The present disclosure has at least one of the following advantages:

(i) The metal stamping cover 111 including the protrusion 1111 is easy to produce and of low cost. In addition, the protrusion 1111 works as a pilot of a first size.

(ii) By assembling the sleeves 2 of different outer diameters to the protrusion 1111, the pilot assembly can meet different applying requirements.

(iii) The process of pressing the sleeve 2 to the outer periphery of the protrusion 1111 is easy and productive.

(iv) By using the tubular sleeve 2 rather than a specially designed, solid, cold-forged part in the prior art to make the pilot, material is saved, the production process is simple and the cost is efficient.

(v) The tubular sleeve 2 is good for mass production, and the long sleeve blank is easy to be cut into short sleeves of different lengths. Furthermore, the sleeves 2 can be machined again after assembling to meet the required length.

Although the embodiments of the present disclosure have been described above, it will be appreciated that the above descriptions are merely exemplary, but not exhaustive; and that the disclosed embodiments are not limiting. A number of variations and modifications may occur to one skilled in the art without departing from the scopes and spirits of the described embodiments. For example,

(i) The cover 111 is not limited to be a metal stamped part; it may be made of other materials or through other processes.

(ii) The sleeve 2 is not limited to be tubular shaped; it may have other possible shapes.

(iii) The connection between the sleeve 2 and the protrusion 1111 is not limited to interference fit; other connection structures or joint materials may also be used, e.g., screw connection or weld.

Claims

A pilot assembly, which is used for a hydraulic torque converter, comprising a cover and a sleeve, wherein the cover includes a protrusion and the sleeve can be attached on the outer periphery of the protrusion,

wherein the protrusion includes a pilot boss of a first size, and

in an assembled condition that the sleeve is attached on the protrusion, the sleeve forms a pilot boss of a second size.
The pilot assembly of claim 1, wherein the inner diameter of the sleeve is smaller than the outer diameter of the protrusion.
The pilot assembly of claim 2, wherein the sleeve is mounted on the protrusion by a press force applied thereon in an axial direction.
The pilot assembly of claim 1, wherein the axial length of the sleeve is greater than the wall thickness of the sleeve in a radial direction.
The pilot assembly of claim 1, wherein the cover is an integrally formed part.
The pilot assembly of claim 1, wherein the cover is a metal stamped part.
The pilot assembly of claim 1, wherein the sleeve is an optional sleeve from a plurality of alternative sleeves of different outer diameters.
A processing method of the pilot assembly of any one of claims 1 to 7, comprising:

providing the cover, wherein the cover is obtained by stamping a metal blank;

providing the sleeve, wherein the inner diameter of the sleeve is smaller than the outer diameter of the protrusion, and the outer diameter of the sleeve is greater than the outer diameter of the protrusion; and

giving a press force to the sleeve in an axial direction, thereby mounting the sleeve on the protrusion in the form of interference fit.
The processing method of the pilot assembly of claim 8 further comprising machining the sleeve to a certain size to form a pilot boss of a specific size.
A hydraulic torque converter, comprising the pilot assembly of any one of claims 1 to 7.