GB2532882A

GB2532882A - Tool and method for preventing a gear from turning

Info

Publication number: GB2532882A
Application number: GB1522643.4A
Authority: GB
Inventors: Dicea Mark; Kolniak Christopher; Kowalske Phillip; Prieskorn Timothy; Vencelov Jeffrey
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2015-12-22
Filing date: 2015-12-22
Publication date: 2016-06-01
Also published as: GB201522643D0; GB2532882A8

Abstract

A tool 24 has a holding section 26 which is configured to mesh with at least one element 34 of a gear 16, the element being spaced apart from teeth 52 of the gear 16. The gear 16 is arranged within a gearbox housing 12, in particular a gearbox housing of a differential for a truck. The tool 24 further has a protruding section 28 which is configured to be in abutment with a portion of the gearbox housing 12 in order to prevent a movement of the tool 24 in a turning direction of the gear 16. The tool 24 is configured to secure a gear 16 to a pinion shaft 18. The holding section may be formed as a ring with one or more recesses 32 on an inner face 30 of the ring, wherein the recesses are configured to accommodate a stud 34 projecting from the centre portion 36 of the gear. A method of using such a tool is also provided.

Description

Tool and method for preventing a gear from turning The invention relates to a tool for preventing a gear from turning, while a pinion nut is loosened or tightened. The pinion nut is configured to secure the gear to a pinion shaft, wherein the gear is arranged within a gearbox housing. The invention further relates to a method for preventing a gear from turning by means of such a tool.

Fig. 1 shows a section of a gearbox 10 which is part of a transmission for a vehicle, in particular of an axle transmission for a truck such as a differential for the truck. The gearbox 10 comprises a gearbox housing 12. Within the gearbox housing 12 are arranged a first helical gear 14 which meshes with a second helical gear 16. The two helical gears 14, 16 drive a pinion shaft 18, on which a pinion 20 is arranged in a torque-proof manner. The second helical gear 16 is secured to the pinion shaft 18 by means of a pinion nut 22.

When trying to remove the pinion nut 22 from the pinion shaft 18, it is necessary to prevent the helical gear 16 from turning. Until now this is typically done by a technician who jams a screwdriver between the helical gear 16 and the gearbox housing 12. The screwdriver thus prevents the gears 14, 16 from turning when the technician loosens (or tightens) the pinion nut 22. However, this method can result in damage to the helical gears 14, 16.

It is therefore the object of the present invention to provide an improved tool and an improved method of the initially mentioned kind.

This object is solved by a tool having the features of claim 1 and by a method having the features of claim 7. Advantageous configurations with convenient further developments of the invention are specified in the dependent claims.

The tool according to the invention has a holding section which is configured to mesh with at least one element of the gear. The at least one element is spaced apart from teeth of the gear. The tool further has a protruding section which is configured to be in abutment with a portion of the gearbox housing in order to prevent a movement of the tool in a turning direction of the gear. This tool makes it possible to refrain from utilizing a screwdriver or the like to block the helical gear, if the pinion nut shall be torqued on the pinion shaft or taken off the pinion shaft. Therefore damaging the gear can be prevented.

As the tool is placed on and secured to the gear by means of the holding section, it is not necessary for the technician to hold the tool once it is arranged on the gear. Therefore, the technician can use both hands to loosen and remove the pinion nut or for tightening the pinion nut upon reassembly. As the protruding section of the tool abuts against the portion of the gearbox housing, the gear is prevented from turning and the pinion nut can easily be loosened or tightened. The tool therefore makes is much easier for the technician or service mechanic to service the pinion without damage to the gear. Thus, an improved tool is provided.

Preferably, the holding section is formed as a ring with at least one recess in an inner face of the ring. Herein the recess is configured to accommodate a stud projecting from a center portion of the gear in a radial direction. The ring can in particular have four recesses which accommodate four studs when the tool is arranged on the gear. This allows the tool to be particularly well secured to the gear.

The protruding section can in particular be formed as a plate like portion of the tool, which extends beyond the teeth of the gear, when the tool is arranged on the gear. Such a configuration allows particularly well to block the protruding section against the gearbox housing, when the tool is arranged on the gear.

Preferably, a length of the protruding section is larger than a radius of the holding section. This enables the technician to easily insert the tool in the gearbox housing in order to secure the tool at its holding section to the gear. At the same time the technician can easily bring the protruding section in abutment with the portion of the gearbox housing in order to prevent the movement of the tool in the turning direction of the gear.

A width of the protruding section can be larger than half a length of the protruding section. Such a configuration provides for a particularly high robustness of the protruding section of the tool.

Finally, it has proven advantageous if the tool has a uniform thickness throughout the holding section and the protruding section. The tool can in particular be made from a plate, for example a metal plate such as a steel plate by machining of the plate. For example the holding section formed as the ring can be machined by drilling a hole into the plate of a given length and width. In a further step smaller holes can be drilled at a border of this hole. Using a file or a die grinder, these smaller holes can then be brought into the desired shape for accommodating the studs of the gear.

In the method according to the invention for preventing a gear from turning by means of a tool, a pinion nut is loosened or tightened. The pinion nut is configured to secure the gear to the pinion shaft. The gear is arranged within a gearbox housing. Herein, the tool is arranged within the gearbox housing such that a holding section of the tool is in engagement with at least one element of the gear, wherein the at least one element is spaced apart from teeth of the gear. The tool is arranged within the gearbox housing such that a protruding section of the tool is in abutment with a portion of the gearbox housing. Herein, the protruding section prevents a movement of the tool in a turning direction of the gear. This method is improved, as it makes is easier for a service mechanic or technician to service the pinion without damage to the gear.

Preferably, a portion of the protruding section passes through an opening in a wall of the gearbox housing, which surrounds the gear. This allows for a particularly good biasing of the tool against the inside of the gearbox housing or axle housing.

The advantages and preferred embodiments described with respect to the tool according to the invention also apply to the method according to the invention and vice versa.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the invention. Thus, implementations are also to be considered as encompassed and disclosed by the invention, which are not explicitly shown in the figures or explained, but arise from and can be generated by separated feature combinations from the explained implementations. Therefore also embodiments and feature combinations shall be considered as disclosed, which do not have all the features of an originally drafted independent claim.

Further advantages, features and details of the invention are apparent from the claims, the following description of preferred embodiments as well as based on the drawings. Therein show: Fig. 1 a part of a gearbox with two helical gears arranged within a gearbox housing; Fig. 2 a perspective view of the gearbox housing according to Fig. 1, wherein a tool for preventing one of the gears from turning is inserted into the gearbox housing; Fig. 3 the tool according to Fig. 2 in a top view; Fig. 4 a section view along a line IV-IV in Fig. 3; Fig. 5 the step of inserting the tool into the gearbox housing such that an end portion of a protruding section of the tool passes through an opening in a wall of the gearbox housing; and Fig. 6 the tool in its working position within the gearbox housing, in which the tool, which is arranged on the gear, prevents the gear from turning.

For an explanation of the components of the gearbox 10 shown in Fig. 1 reference is made to the introductory part of the present description.

In Fig. 2 a tool 24 in the form of a specially designed wrench is shown, which is configured to hold the helical gear 16, i.e. to prevent the helical gear 16 from turning, for example when the pinion nut 22 shall be loosened. The tool 24 has a holding section 26 which is formed as a ring and a protruding section 28 which extends in a radial direction from the ring portion. In an inner face 30 of the ring forming the holding section 26 four recesses 32 are provided. The inner shape of each of these four recesses 32 corresponds to the outer dimensions of four studs 34 which project in a radial direction from a center portion 36 of the gear 16. In the gearbox 10 shown in Fig. 2 the studs 34 have a rectangular outline. The recesses 32 have a corresponding rectangular shape.

As can be seen from Fig. 3, a length 38 of the protruding section 28 can be slightly larger than a radius 40 of the ring forming the holding section 26. A total length 42 of the tool 24 can be about 20 cm, whereas a width 44 of the protruding section 28 can be about 5 cm. The plate like tool 24 can have a thickness 46 in the range of about 6 mm to about 15 mm (see Fig. 4). The tool 24 can in particular be made from steel.

Fig. 5 shows how the tool 24 is inserted into the gearbox housing 12. Herein, an end portion 50 (see Fig. 2 and Fig. 6) of the protruding section 26 passes through an opening provided in a wall 48 of the gearbox housing 12. This wall 48 circumferentially surrounds the helical gear 16. The opening is provided in a section of the wall 48, which separates a chamber of the gearbox housing 12, in which the second helical gear 16 is arranged, from another chamber of the gearbox housing 12, in which the first helical gear 14 is arranged.

Fig. 6 shows the tool 24 in its working position, in which the tool 24 is secured to the helical gear 16. The wrench or tool 24 is placed on the helical gear 16 and secured to the helical gear 16 such that the studs 34 come to lie within the recesses 32. In other words the wrench fits over the studs 34 on the helical gear 16. The wrench or tool 24 thus holds the helical gear 16 in place or prevents the helical gear 16 from spinning or turning while the pinion nut 22 is removed from the pinion shaft 18. As the tool 24 prevents the helical gear 16 from turning, it is possible to torque the pinion nut 22 on or off without damaging the helical gear 16.

When a person such as a technician or service mechanic loosens the pinion nut 22, the protruding section 28 of the tool 24 is biased against the parts of the wall 48 which delimit the opening within the wall 48 through which the protruding section 28 extends.

As the tool 24 in the working position shown in Fig. 6 prevents the gear 16 from turning, the service mechanic or technician can use two hands to loosen and remove the pinion nut 22.

As can be further seen from Fig. 6, the protruding section 28 extends beyond teeth 52 of the helical gear 16, when the tool 24 is arranged on the helical gear 16 or secured to the helical gear 16 by the studs 34 of the gear 16. In other words the wrench or tool 24 uses the four lugs or studs 34 on the helical gear 16 to hold the helical gear 16 in place and prevent it from turning, while the pinion nut 22 is being torqued on or torqued off.

Therefore no hands are needed to hold the tool 24. This leaves both hands free for handling a torque wrench or the like which can be utilized to remove the pinion nut 22 or to tighten the pinion nut 22 upon reassembly after servicing of the pinion 20 and/or the pinion shaft 18 or other components of the gearbox 10.

List of reference signs gearbox 12 gearbox housing 14 gear 16 gear 18 pinion shaft pinion 22 pinion nut 24 tool 26 holding section 28 protruding section face 32 recess 34 stud 36 center portion 38 length radius 42 length 44 width 46 thickness 48 wall end portion 52 teeth

Claims

Claims 1. Tool for preventing a gear (16) from turning while a pinion nut (22) is loosened or tightened which is configured to secure the gear (16) to a pinion shaft (18), wherein the gear (16) is arranged within a gearbox housing (12), in particular a gearbox housing (12) of a differential for a truck, characterized in that the tool (24) has a holding section (26) which is configured to mesh with at least one element (34) of the gear (16), which is spaced apart from teeth (52) of the gear (16), and a protruding section (28) which is configured to be in abutment with a portion of the gearbox housing (12) in order to prevent a movement of the tool (24) in a turning direction of the gear (16).
2. Tool according to claim 1, characterized in that the holding section (26) is formed as a ring with at least one recess (32) in an inner face (30) of the ring, wherein the recess (32) is configured to accommodate a stud (34) projecting from a center portion (36) of the gear (16) in a radial direction.
3. Tool according to claim 1 or 2, characterized in that the protruding section (28) is formed as plate like portion of the tool (24), which extends beyond the teeth (52) of the gear (16), when the tool (24) is arranged on the gear (16).
4. Tool according to any one of claims 1 to 3, characterized in that a length (38) of the protruding section (28) is larger than a radius (40) of the holding section (26).
5. Tool according to any one of claims 1 to 4, characterized in that a width (44) of the protruding section (28) is larger than half a length (38) of the protruding section (28).
6. Tool according to any one of claims 1 to 5, characterized in that the tool (24) has a uniform thickness (46) throughout the holding section (26) and the protruding section (28).
7. Method for preventing a gear (16) from turning by means of a tool (24), while a pinion nut (22) is loosened or tightened which is configured to secure the gear (16) to a pinion shaft (18), wherein the gear (16) is arranged within a gearbox housing (12), in particular a gearbox housing (12) of a differential for a truck, characterized in that the tool (24) is arranged within the gearbox housing (12) such that a holding section (26) of the tool (24) is in engagement with at least one element (24) of the gear (16), which is spaced apart from teeth (52) of the gear (16), and such that a protruding section (28) of the tool (24) is in abutment with a portion of the gearbox housing (12), wherein the protruding section (28) prevents a movement of the tool (24) in a turning direction of the gear (16).
8. Method according to claim 7, characterized in that a portion (50) of the protruding section (28) passes through an opening in a wall (48) of the gearbox housing (12), which surrounds the gear (16).