SE542739C2

SE542739C2 - A pad for a gear shift fork

Info

Publication number: SE542739C2
Application number: SE1851387A
Authority: SE
Inventors: Mats Åberg
Original assignee: Scania Cv Ab
Priority date: 2018-11-09
Filing date: 2018-11-09
Publication date: 2020-07-07
Also published as: WO2020096508A1; SE1851387A1

Abstract

A pad for a gear shift fork has a pad member (7) of plastic having a flat surface (8) configured to be applied on a shift sleeve in a gear box and a metal member (6) joined to the pad member and providing means (11, 1 2) for securing the pad to a gear shift fork. The metal member has a plate-like base portion (3) carrying the pad member (7) and extending with large flat surfaces (9) thereof in parallel or substantially in parallel with the flat surface (8) of the pad member. Securing means (11, 12) is provided by at least one base portion section (13, 14) extending beyond borders (15, 16) of the pad member (7).

Description

A pad for a gear shift fork TECHNICAL FIELD OF THE INVENTION AND BACKGROUND ART The present invention relates to a pad for a gear shift fork comprising • a pad member of plastic having a flat surface configured to be applied on a shift sleeve in a gear box, and · a metal member joined to the pad member and providing means for securing the pad to a gear shift fork.

Gear shift forks having such pads are especially used for gear shifting in gear boxes in motor vehicles, and the pad members thereon have in the past been made of a metal material, such as bronze. However, it has been realized that the use of plastic as the material for the pad would have the advantages of reduction of costs and a better environmental performance, since bronze in this application contains lead. Attempts have been bade to introduce plastic pads for gear shift forks, but it has not been succeeded to achieve sufficient strength in the connection between the pads and a gear shift fork.

This has led to attempts to make only the pad member of plastic and to provide means of metal for securing the pad to a gear shift fork and joining these means with the plastic pad member as defined in the introduction. US 2010/0132498 A1 discloses a pad for a gear shift fork of this type. The plastic pad member of that pad is carried by a metal member forming a skeleton of the pad with a considerable volume. This considerable volume of the metal member results in difficulties to manufacture the pad member and join it to the metal member by injection moulding of the plastic, since the metal member will “steal” a lot of heat from the flowing plastic.

SUMMARY OF THE INVENTION The object of the present invention is to provide a pad for a gear shift fork of the type defined in the introduction being improved in at least some aspect with respect to such pads already known.

This object is according to the invention obtained by providing such a pad with the features listed in the characterizing part of appended patent claim 1.

Thus, the metal member has a plate-like base portion carrying the pad member and extending with large flat surfaces thereof in parallel with or substantially in parallel with the flat surface of the pad member, and the securing means is provided by at least one base portion section extending beyond borders of the pad member. By using a plate-like base portion to carry the pad member and also provide the securing means for securing the pad to a gear shift fork the pad will receive a simpler design and the metal member may be given a considerably reduced volume with respect to the metallic member of the known pad discussed above, so that it may be produced to a lower cost and in the case of using injection moulding for this production this may be easily carried out with an excellent result.

According to an embodiment of the invention the base portion of the metal member is made of a thin sheet. It has been found sufficient to use a thin sheet, such as a steel sheet, as said base portion for joining to the pad member and providing means for securing the pad to a gear shift fork or as the entire or substantially the entire metal member of the pad as in another embodiment of the invention. This will result in a pad with a reliable function to a low cost.

According to another embodiment of the invention the metal member has thin sheet sections bent from the thin sheet base portion to extend into the pad member in the direction towards said flat surface of the pad member for joining the metal member to the pad member. Such thin sheet sections will result in an efficient joining of the metal member carrying the pad member to the pad member by use of small amounts of metal material for obtaining this.

According to another embodiment of the invention said bent sections extend from the base portion by making an angle of 90° or substantially 90° with respect thereto, which results in a reliable securing of the pad member to the metal member.

According to another embodiment of the invention the bent sections have a series of spaced apart projections, which according to another embodiment of the invention are gradually broadened as seen in the direction of the extension thereof towards the flat surface of the pad member. A strong and reliable connection of the pad member to the metal member is so achieved.

According to another embodiment of the invention the thin sheet of the metal member has a thickness of 0.1-1 mm, 0.1-0. 6 mm or 0.3-0. 5 mm. Such thin sheet material resulting in superior properties when injection moulding the plastic of the pad member will still be strong enough for providing strong means for securing the pad to a gear shift fork.

According to another embodiment of the invention said securing means comprises at least one female member being a part of said metal member and configured to secure the pad to a gear shift fork by engagement with a male member or a male member being a part of said metal member and configured to secure the pad to a gear shift fork by engagement with a female member. These are preferred ways of obtaining securing of a pad according to the invention to a gear shift fork.

According to another embodiment of the invention the metal member has female securing means in the form of one or more through-holes in the base portion. In such a case a male member in the form of for instance a screw or a bolt may be introduced through said at least one through-hole and tightened for securing the pad to a gear shift fork.

According to another embodiment of the invention the pad member has been formed by injection moulding of plastic around the metal member. A joining of the pad member to the metal member may by this be easily obtained.

According to another embodiment of the invention the pad member is formed by a fibre reinforced plastic, such as fibre reinforced Polyetheretherketon, for instance Victrex PEEK 450CA30, or fibre reinforced Polyphenylensulfide, for instance Celanese Fortron 1140 L4. These are suitable plastics for the pad member, which has to withstand high temperatures, such as at least 120°C, and have certain wear properties.

The invention also relates to a gear shift fork, a gear box for a motor vehicle and a method for producing a pad for a gear shift fork according to the appended claims directed thereto.

Further advantages as well as advantageous features of the invention will appear from the description following below.

BRIEF DESCRIPTION OF THE DRAWINGS With reference to the appended drawings, below follows a specific description of an embodiment of the invention cited as an example.

In the drawings: Fig 1 is a view of a blank of thin sheet to be used for creating a metal member to be joined to a pad member in a pad according to an embodiment of the invention, Fig 2 is a perspective view from above of a pad according to an embodiment of the invention, Fig 3 is a view in the direction of the arrow III in Fig 2 of the pad shown in Fig 2, and Fig 4 is a schematic view of a gear shift fork provided with a pad according to the present invention.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION A pad 1 for a gear shift fork according to an embodiment of the invention will now be described while making reference to Figs 1 -3. Fig 1 shows a blank of thin sheet used to form a metal member of the pad. The blank 2 has a thickness of 0.3-0. 5 mm and a platelike rectangular base portion used to carry the pad member of the pad with a length of approximately 50 mm. The thin sheet blank 2 has sections 4 to be bent from the thin sheet base portion 3 to extend from this base portion by making an angle of 90° or substantially 90° with respect thereto and have a series of spaced apart projections 5 which are gradually broadened as seen in the direction of extension thereof away from the base portion 3.

When manufacturing the pad according to the invention a metal member 6 thereof is formed out of the blank 2 shown in Fig 1 by bending the sections 4 as shown in Figs 2 and 3. A pad member 7 of plastic is then formed by injection moulding of a plastic onto the metal member 6, which will then carry the pad member and be joined thereto primarily by the sections 4 bent from the base portion 3. It is shown how the pad member 7 has a flat surface 8 configured to be applied on a shift sleeve in a gear box. The base portion 3 of the metal member 6 carrying the pad member 7 extends with large flat surfaces 9, 10 thereof in parallel or substantially in parallel with the flat surface 8 of the pad member Means for securing the pad to a gear shift fork are provided by through-holes 11, 12 in base portion sections 13, 14 extending beyond borders 15, 16 of the pad member 7.

Fig 4 illustrates very schematically how two pads 1 according to the invention are secured to a gear shift fork 17 configured to be applied on a shift sleeve in a gear box 18 of a motor vehicle 19. The pads are secured to the gear shift fork by bolts 20 introduced through the through-holes 11, 12 in the sections 13, 14 of the plate-like base portion of the metal member 6 and then into inner threads in the fork and then tightened.

The invention is of course in no way restricted to the embodiment described above, since many possibilities for modifications thereof are likely to be obvious to one skilled in the art without having to deviate from the scope of the invention defined in the appended claims.

The entire plate-like base portion extends in the longitudinal direction rectilinearly at least from one end of the pad member to an opposite end thereof.

The pad may have another number than two securing means provided by said at least one base portion section extending beyond borders of the pad member, such as only one or more than two, and such securing means may be of another type than through-holes, such as pins of metal projecting from said section to enter into engagement with corresponding members on a gear shift fork.

Claims

1. A pad (1) for a gear shift fork (17) comprising • a pad member (7) of plastic having a flat surface (8) configured to be applied on a shift sleeve in a gear box, and • a metal member (6) joined to the pad member (7) and providing means (11, 12) for securing the pad (1) to the gear shift fork (17), characterized in that the metal member (6) has a plate-like base portion (3) carrying the pad member (7) and extending with flat surfaces (9, 10) thereof in parallel with or substantially in parallel with said flat surface (8) of the pad member (7), and that said securing means (11, 12) is provided by at least one base portion section (13, 14) extending beyond borders (15, 16) of the pad member (7).

2. A pad according to claim 1, characterized in that the base portion (3) of the metal member (6) is made of a sheet.

3. A pad according to claim 2, characterized in that the entire or substantially the entire metal member (6) is made of a sheet.

4. A pad according to claim 3, characterized in that the metal member (6) has sheet sections (4) bent from the sheet base portion (3) to extend into the pad member (7) in the direction towards said flat surface (8) of the pad member for joining the metal member (6) to the pad member (7).

5. A pad according to claim 4, characterized in that said bent sections (4) extend from the base portion (3) by making an angle of 90° or substantially 90° with respect thereto.

6. A pad according to claim 4 or 5, characterized in that said bent sections (4) have a series of spaced apart projections (5).

7. A pad according to claim 6, characterized in that said projections (5) are gradually broadened as seen in the direction of the extension thereof towards said flat surface (8) of the pad member (7).

8. A pad according to any of claims 2-7, characterized in that said sheet has a thickness of 0.1-1 mm, 0.1-0. 6 mm or 0.3-0. 5 mm.

9. A pad according to any of the preceding claims, characterized in that said securing means comprises at least one female member (11, 12) being a part of said metal member (6) and configured to secure the pad (1) to a gear shift fork (17) by engagement with a male member (20) or a male member being a part of said metal member and configured to secure the pad (1) to a gear shift fork by engagement with a female member.

10. A pad according to claim 9, characterized in that the metal member (6) has female securing means in the form of one or more through-holes (11, 12) in the base portion (3).

11. A pad according to any of the preceding claims, characterized in that the pad member (7) has been formed by injection moulding of plastic around the metal member (6).

12. A pad according to any of the preceding claims, characterized in that the pad member (7) is formed by a fibre reinforced plastic, such as fibre reinforced Polyetheretherketon, for instance Victrex PEEK 450CA30, or fibre reinforced Polyphenylensulfide, for instance Celanese Fortron 1 140 L4.

13. A gear shift fork, characterized in that it has two pads (1) according to any of the preceding claims.

14. A gear box for a motor vehicle, characterized in that it is provided with at least one gear shift fork (17) having two pads (1) according to any of claims 1 -12.

15. A method for producing a pad for a gear shift fork according to any of claims 1-12, characterized by injection moulding of a plastic around a thin sheet metal member (6) having a platelike base portion (3).