Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
  • F16H61/24—Providing feel, e.g. to enable selection
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
  • F16H61/24—Providing feel, e.g. to enable selection
  • F16H2061/246—Additional mass or weight on shift linkage for improving feel

Definitions

• the present invention relates to a device for increased gear shifting comfort in a manual gear shift in a gearbox, which device is disposed in a motor vehicle.
• the motions of the gear shift lever are transmitted via a rod or wire system to the control housing of the gearbox.
• the control housing is usually disposed on the top side of the gearbox.
• a control shaft which is mounted such that it is rotatable and axially displaceable.
• the rod or wire system of the gear shift lever is usually coupled to one shaft end of the control shaft so as to convert the motions of the lever into rotary motions and into displacing motions of the control shaft in the axial direction thereof.
• the control shaft is then further coupled to gear shift forks inside the gearbox, which gear shift forks, in a known manner, displace coupling sleeves for the engagement and disengagement of different gears.
• FIG. 1 shows in diagrammatic representation a side view of a gearbox 5 according to the prior art, having a front part 7 coupled to a vehicle engine (not shown) , a rear part 6 coupled via a transmission (not shown) to the drive wheels (not shown) of the vehicle, a control housing 4 and a damping mass 1 fixedly disposed on a control shaft 2.
• the weight and radius of the damping mass 1 is tailored such that a predetermined moment of inertia is obtained for increased gear shifting comfort.
• the control shaft 2 When a gear is engaged, the control shaft 2 is rotated a bit clockwise or counterclockwise (depending on the selected gear) from a neutral position (see motion arrow 3 in figure 1) .
• the control shaft 2 can also be displaced a bit along its own geometrical axis (axial direction) and then rotated again for the selection of further gears .
• a gear shift lever with rod or wire system is not shown in figure 1.
• the gearbox 5 in figure 1 is in its neutral position and the damping mass 1 is then in its lowermost position.
• the neutral position of the damping mass is obtained by positioning the damping mass straight up in relation to the control shaft.
• the damping mass does not therefore hang downward from the control shaft.
• the invention according to the present application produces greatest benefits, however, where a damping mass is used which has its neutral position in a position hanging downward from the control shaft, as shown in figure 1.
• the control shaft When a gear is engaged, the control shaft is rotated until reaching a stop (not shown) built into the gearbox. The stop also stops the motion of the damping mass, which can produce large and sudden torques over the control shaft.
• the control shaft When driving over bumps or the like, the control shaft experiences increased load, since the damping mass 1 is arranged with an overhang. The damping mass 1 can also cause it and the control shaft 2 to start vibrating, which risks fatiguing the control shaft. In the worst case, the various torques which are described above can lead to breakage of the control shaft.
• damping mass in a manually operated vehicle gearbox is shown, for example, by US 2003/0131679.
• Patent claims 1 and 8 describe preferred embodiments and refinements of the device according to the invention.
• the device according to the invention is a damping mass for increased gear shifting comfort, fixedly disposed on a control shaft of a motor vehicle gearbox.
• the control shaft is coupled to at least one gear shift fork disposed in the gearbox and to a gear shift lever for manual selection of a gear in the gearbox.
• the invention is characterized in that, in the damping mass, a cavity extends substantially along a predetermined radius at a distance from the geometrical center of the control shaft, and in that a body having a certain predetermined weight is designed to move relative to the damping mass, preferably along said radius in the cavity.
• the cavity around the body is filled with a fluid having a predetermined viscosity.
• the cavity is configured as a closed, preferably cylindrical chamber, which chamber extends and is curved along said radius .
• the body is preferably cylindrical, having the same curvature as the chamber, but with a substantially shorter extent along the radius than the chamber, so that space is obtained for the motion of the body.
• the body is arranged in the chamber with a predetermined clearance between the shell surface of the body and the walls of the chamber, so that the motion of the body relative to the motion of the damping mass along said radius can be predetermined.
• the speed of motion of the body relative to the damping mass depends primarily on the viscosity of the fluid, the clearance between the walls of the chamber and the shell surface of the body, as well as the weight of the body.
• Figure 2 shows in diagrammatic representation a side view of the damping mass according to the invention when the gearbox is in its neutral position.
• Figure 3 shows in diagrammatic representation a side view of the damping mass according to the invention when the gearbox is in a position in which a gear is engaged.
• FIG. 2 shows the damping mass 25 according to the invention when the gearbox (not shown) is in its neutral position, i.e. the damping mass 25 is in its lowermost position.
• the damping mass 25 is fixed on a control shaft 24, for example, as in the shown illustrative embodiment, by a part 20, formed as a hollow cylinder, which is fixedly disposed on the control shaft 24.
• the damping mass 25 and the control shaft 24 are rotatable 22 from the shown neutral position into gear positions, situated in the counterclockwise and/or clockwise direction, around the geometrical center 29 of the control shaft.
• the damping mass 25 extends in the radial direction out from the geometrical center 29 of the control shaft by virtue of the part 21, which connects the hollow cylinder 20 to a part 27 which forms walls and end faces 32 and 33 for a cavity 28 in which a body 23 is movably disposed.
• the parts 20, 21 and 27 are preferably cast in one piece in a relatively light (low density) material, for example aluminum.
• the cavity 28 has the form of a closed cylindrical chamber, which chamber 28 has an extent along a predetermined radius from the geometrical center 29 of the control shaft.
• the body 23, too, is in the form of a cylinder, but which, according to the illustrated embodiment, has only around 2/3 of the extent along the predetermined radius which the chamber 28 has.
• the body 23 is preferably homogenous and made in a relatively heavy material (high density) , for example steel/cast iron. By virtue of the gravitational force and the configuration of the body 23 and of the chamber 28, the body 23 slides down into its lowermost position, as is shown by figure 2.
• the fluid 30 is preferably a liquid with low temperature sensitivity, for example a silicone oil.
• the body 23 is disposed in the chamber 28 with a certain predetermined clearance 26, which, together with the viscosity of the fluid 30, substantially determines how easily and at what speed the body 23 can move along the predetermined radius and relative to the part 27.
• Figure 3 shows the same embodiment according to the invention as in figure 2, but in a situation in which the gearbox (not shown) has a gear engaged, i.e. the damping mass 25 has in figure 3 rotated a bit counterclockwise 31 from its lowermost position (the neutral position) .
• Figure 3 shows what happens a short while after the gear position has been adopted. As shown in figure 3, the body 23 slides down into its lowermost position, which means that the torque over the control shaft 24, which tends to disengage the gear, is heavily reduced.
• the viscosity of the fluid 30 and the clearance 26 are tailored such that sufficient inertia for the ease at which the body 23 can move relative to the part 27 is obtained, in connection with the rotation of the damping mass 25 from the neutral position into a gear position (or vice versa) .
• the torque effect from the total weight of the damping mass 25, i.e. inclusive of the weight of the body 23 and of the fluid 30, can thereby be maintained at the point of gear shift, for good gear shifting comfort, whereas the torque effect from the body 23 is heavily reduced directly after the damping mass 25 has changed position (been rotated) and the body 23 has managed to slide down into its lowermost position according to figure 3.
• the end faces 32, 33 of the chamber 28 can be mutually connected by a duct with predetermined flow area, which flow area largely determines the motion and speed of the body 23 relative to the damping mass 25.
• the chamber 28 and the body 23 can have a form other than cylindrical, for example spherical, of square cross section or of oval cross section.
• the body might also be imagined to consist of a plurality of bodies, for example two balls.
• Another possibility is that the chamber and the body do not need to be curved exactly along a certain radius, but that a certain deviation from the radius is possible.
• the invention works best if a certain radius is utilized for the curvature of the chamber and the body around the geometrical center of the control shaft.
• the fluid may also be constituted by a gas, for example air.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Fluid-Damping Devices (AREA)
• Axle Suspensions And Sidecars For Cycles (AREA)

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• 2004
  • 2004-09-07 SE SE0402150A patent/SE527630C2/sv not_active IP Right Cessation
• 2005
  • 2005-08-30 WO PCT/SE2005/001252 patent/WO2006041347A1/en not_active Ceased
  • 2005-08-30 EP EP05776364A patent/EP1792108A1/de not_active Withdrawn

Non-Patent Citations (1)

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