Manual torque-limiting actuation system

Abstract

The invention relates to an actuation system (1) comprising an end housing (5) having an internal through channel (7), an activation nut (9) having a threaded internal channel (15) and an elongated rod (16) comprising a threaded external surface (18), the rod (16) having a first end and a second end to which an actuation cable (4) is fixed, and rotation of the activation nut (9) causes translational movement of the rod (16) along the internal through channel (7). According to the invention, the rod (16) has a section (19) whose external surface is smooth without any thread, said section (19) being placed along the rod (16) in such a way that a clearly identified position of said rod (16) is reached when said section (19) has entirely reached the internal threaded channel (15) of the activation nut (9). Figure for abstract: Figure 3

Description

Title of the invention: Manual actuation system with torque limitation

[0001] The present invention relates to a manual actuation system with torque limitation. Such an actuation system is preferably placed in a vehicle, and can for example activate or deactivate a parking function of said vehicle.

[0002] For the avoidance of doubt, the actuator housing and the end housing refer to the same object.

[0003] The principle of such a system is based on the sliding of a hollow rod inside an internal channel of an end housing, said sliding being achieved by means of an activation nut secured to said end housing and through which the rod passes. The activation nut has a threaded internal channel and is rotatably mounted on the end housing. An external surface of the hollow rod is threaded, so that a clockwise rotation of the activation nut causes a translation of the hollow rod in the internal channel, and a counterclockwise rotation of said activation nut causes a translation in the opposite direction of said hollow rod in said internal channel.The hollow rod has a first end and a second end considered along a longitudinal axis of said rod, and has a longitudinal axis which is parallel to the longitudinal axis of the internal channel of the end housing in which it is housed. By rotating the activation nut, the hollow rod can thus pass: . -a first position for which the first end emerges slightly from the activation nut towards the outside of the end box, and the second end is positioned at a great depth in the internal channel of said end box, - to a second position for which the first end emerges more significantly from the activation nut than in the first position, towards the outside of the end housing, and the second end is positioned at a shallower depth in the internal channel of the end housing than in the first position.

[0004] A transmission cable is secured to the second end of the hollow rod, and moves with the same amplitude as that of the hollow rod when the nut is rotated and causes a translational movement of said hollow rod in the internal channel of the end housing. More precisely, a first end of the cable is secured to the second end of the hollow rod, and a second end of the cable is secured to an actuating part.When the cable moves under the effect of the displacement of the hollow rod in the internal channel of the end box, it moves the actuating part with the same amplitude of displacement which will then exert . a particular function within the vehicle.

[0005] However, a disadvantage of this type of actuation system is that when the activation nut is rotated by a user in a direction allowing the hollow rod to reach the second position, nothing prevents this user from continuing to rotate the activation nut once said hollow rod has reached the second position. Generally, the manipulation of the activation nut is carried out by means of a tool which may for example be pliers, and it is easy to see what the level of damage to the actuation system could be when excessive rotation of the activation nut using this tool.

[0006] An actuation system according to the invention operates on the same principle as that described above, but which overcomes the main drawback mentioned above.

[0007] The subject of the invention is an actuation system comprising an end housing having an internal through channel, an activation nut comprising a threaded internal channel and an elongated rod comprising a threaded external surface, the activation nut being placed at a first end of the internal through channel of the end housing so that the axis of revolution of the activation nut and the axis of revolution of the internal through channel coincide, the elongated rod passing through the activation nut and extending into the internal channel of the end housing, the rod having a first end and a second end to which an actuation cable is fixed, and rotation of the activation nut causes translational movement of the rod along the internal through channel allowing said rod to pass: -from a first position for which the first end emerges slightly from the activation nut towards the outside of the end box, and the second end is positioned at a significant depth in the internal channel of said end box, -to a second position for which the first end emerges from the activation nut more significantly than in the first position, towards the outside of the end box, and the second end is positioned at a shallower depth in the internal channel of the end box than in the first position.

[0008] According to the invention, the rod has a section whose external surface is smooth without any thread, said section being placed along the rod in such a way that the second position of said rod is reached when said section has entirely reached the internal threaded channel of the activation nut.

[0009] The originality of an actuation system according to the invention is that, once the rod has reached the second position, the entire smooth section is found in the nut so that there is no longer any interaction between said activation nut and said rod except for simple contact. In other words, once the smooth section of the rod is placed inside the activation nut, rotating said activation nut has no effect on the rod and therefore no longer causes any movement of said rod. In this way, a user wishing to make the rod reach the second position does not risk forcing the activation nut once said rod has reached said position, since at that moment, the activation nut will start to rotate freely. This user will therefore not be able to force the activation nut and cause damage to said actuation system. Preferably, the rod is placed in the internal channel of the end housing so that the longitudinal axes of said rod and said channel are parallel.The operating principle of an actuation system according to the invention is to cause a translational movement of the rod in the internal channel of the end housing by means of a rotation of the activation nut in order to move the actuation cable with the same amplitude as that of the rod. By moving under the effect of the rod which translates, the cable will move or activate an actuation part fixed to the end of said cable, in order to fulfill a particular function. The end housing constitutes a control box from which the actuation system is triggered. Advantageously, the activation nut must be turned clockwise to move the rod from the first position to the second position, and counterclockwise to move said rod from the second position to the first position.Advantageously, the rod and the internal channel of the end housing are two rectilinear elements.

[0010] According to a possible characteristic of the invention, the length of the smooth section of the rod is greater than or equal to the length of the internal threaded channel of the activation nut. Indeed, if the length of this smooth section were less than that of the activation nut, a part of the external surface of the rod which is threaded, would be in interaction with the internal threaded channel of said activation nut, this configuration falling outside the scope of the present invention.

[0011] According to a possible characteristic of the invention, the rod, the smooth section and the internal threaded channel of the activation nut are cylindrical in shape, the external diameter of the smooth section of the rod being smaller than the diameter of the internal threaded channel of the activation nut so that a clearance is created between them when the smooth section has completely reached said internal threaded channel. In this way, when the smooth section of the rod is completely inserted into the activation nut, a clearance is created which is perfectly detectable by the user, indicating that the second position of the rod has been reached.

[0012] According to a possible characteristic of the invention, the rod is hollow and the second end of said rod has a first tube of reduced size connecting an internal space of said rod to an external space thereof, a first end of the actuating cable having an enlarged head which is wider than said first tubing, said actuating cable being fixed to the second end of the rod by means of an insertion of the enlarged head of said cable into the internal space of said rod and a passage of said cable into said first tubing. The fixing of the first end of the cable to the second end of the rod is carried out by means of an insertion of an enlarged head of said cable into an internal space of said rod, without the possibility of said cable being able to be easily removed, since the enlarged head has dimensions which are greater than those of the first tubing. Advantageously, the external space of the rod is constituted by the internal channel of the end housing.

[0013] According to a possible characteristic of the invention, a second end of the internal channel of the end housing has a second tube having the same diameter as that of the first tube and being in perfect continuity with said first tube, the cable emerging from the end housing by passing through said second tube. For this configuration, the enlarged head of the cable is inserted into the internal space of the rod, said cable passing through the first and second tubes before extending towards the outside of the end housing.

[0014] According to a possible characteristic of the invention, a second end of the cable which is external to the end housing, is associated with a pre-stressed return element, so that the enlarged head of said cable remains in abutment against an internal wall delimiting the second end of the hollow rod. This pre-stressed return element, which can for example be a spring, tends to maintain the enlarged head of the cable in the second end of the rod, and when said rod passes from the first position to the second position, the movement of the latter is carried out at the cost of a certain effort to overcome the return force of said spring.Similarly, when the rod has reached the second position corresponding to an insertion of the smooth segment into the activation nut, a rotation of the rotation nut to allow the rod to reach the first position is carried out naturally under the effect of the tensile force of said spring which will allow the threaded external surface of said rod to be inserted into the thread of the internal channel of the end housing.

[0015] According to a possible characteristic of the invention, the second end of the cable is connected to an actuating part which is set in motion by the cable which moves together with the rod in the end housing.

[0016] According to a possible characteristic of the invention, the first end of the rod has an enlarged washer which is in contact with the activation nut when the rod is in the first position. This washer acts as a stop, allowing the rod moving to reach the first position, to stop its travel as soon as said washer is in contact with said activation nut.

[0017] According to a possible characteristic of the invention, the end box comprises fixing means intended for fixing said end box to an external structural element. Indeed, the end box being intended to remain fixed, it has fixing means allowing it to be fixed to a wide range of structural elements which are external to said end box.

[0018] According to a possible characteristic of the invention, said actuation system serves to control the parking function of the vehicle, so that in the first position, the rod activates the parking function of the vehicle and in the second position it deactivates this function.

[0019] An actuation system according to the invention has the advantage of having safe, reliable and repetitive operation, by means of a simple and clever structural modification of the rod, said modification being easily machinable. As a result, this structural modification is inexpensive. It also has the advantage of being a little lighter, because the structural modification consists of locally refining the rod, which corresponds to a removal of material. Finally, it has a constant size compared to existing actuation systems.

[0020] A detailed description of a preferred embodiment of an actuation system according to the invention is given below, with reference to the following figures:

[0021] [Fig.l] [Fig.l] is a perspective view of an actuation system according to the invention in its environment in a vehicle,

[0022] [Fig.2] [Fig.2] is a sectional view of an end box of a system actuating device according to the invention, in the first position,

[0023] [Fig.3] [Fig.3] is a sectional view of an end box of a system actuating device according to the invention, in the second position,

[0024] [Fig.4] [Fig.4] is a perspective view of an end box of a system actuating device according to the invention, in the first position,

[0025] [Fig.5] [Fig.5] is a perspective view of an end box of a system actuating device according to the invention, in the second position,

[0026] [Fig.6] [Fig.6] is a side view of an actuating part of a system actuating device according to the invention, in two different positions.

[0027] Referring to [Fig.l], an actuation system 1 according to the invention can, for example, be placed in a motor vehicle to activate a parking function of said vehicle. Such an actuation system 1 comprises an upstream part 2 for controlling said system 1, and a downstream part 3 for performing a function which will have been previously controlled by the upstream part 2, in this case the parking function of the vehicle, said two parts being connected to each other by means of an actuation cable 4.

[0028] The present invention relates to an improvement made to the upstream part 2 of the 1. actuation system

[0029] Referring to Figures 2 and 3, the upstream part 2 of this actuation system 1 comprises an actuation housing 5 comprising an elongated cylindrical body 6, provided with an internal through channel 7, extending along a longitudinal axis of said body 6. This internal channel 7 is cylindrical and has: - a first end 8 on which an activation nut 9 is rotatably mounted, and -a second end 10 ending in a circular wall 11 extending perpendicular to the axis of revolution of the internal channel 7, said circular wall 11 being crossed in its center by a second through tube 12, of reduced diameter compared to the diameter of the circular wall 11. This second tube 12 of reduced diameter has an axis of revolution which is coincident with that of the internal channel 7 of the elongated cylindrical body 6.

[0030] The activation nut 9 has a cylindrical body 13 and an enlarged cylindrical head 14 extending said cylindrical body 13 while being centered thereon. The external diameter of the enlarged head 14 of the activation nut 9 is greater than the external diameter of the body 13. The activation nut 9 has a threaded internal channel 15, passing through both the enlarged head 14 and the body 13, the two ends of this threaded internal channel 15, considered along the axis of revolution of said activation nut 9, are open and each open onto the outside of said activation nut 9. The activation nut 9 is mounted on the first end 10 of the internal channel 7 of the elongated cylindrical body 6, so that: - the cylindrical body 13 of said activation nut 9 is placed inside said internal channel 7, and -the enlarged head 14 of this activation nut 9 comes to bear against an annular wall of the cylindrical body 6 of the actuating housing 5, surrounding the first end 8 of the internal channel.

[0031] An elongated rod 16 is placed in the internal channel 7 of the cylindrical body 6 of the actuating housing 5. This rod 16 is hollow and has over its entire length a cylindrical internal channel 17, of constant diameter. It is in the form of three distinct sections: -a first cylindrical section 18 having a constant external diameter, and one external surface of which is threaded. The dimensions of this first section 18 are compatible with the dimensions of the threaded internal channel 15 of the activation nut 9, so that said first section 18 can be screwed into said internal channel 15, - a second cylindrical section 19 having a smooth external surface, and an external diameter which is less than the external diameter of the first cylindrical section 18, -a third cylindrical section 20 comprising a flared bead 21 whose external diameter is greater than that of the first cylindrical section 18. This third cylindrical section 20 ends with a first tube 22 extending the internal channel 17 of the rod 16, the diameter of said first tube 22 being less than that of the internal channel 17 of said rod 16. The three sections 18, 19, 20 are in continuity with each other, the second section 19 being inserted between the first section 18 and the third section 20. The three sections 18, 19, 20 are coaxial, a free end of the first section 18 constituting a first end of the rod 16, and the flared bead 21 of the third cylindrical section 20 constituting a second end of said rod 16. The rod 16 also comprises a widened end washer 26, which is secured to the first end of said rod 16 and which protrudes radially from the latter.

[0032] The external diameter of the bead 21 of the third cylindrical section 20 is slightly smaller than the diameter of the internal channel 7 of the cylindrical body 6 of the end housing 5. In this way, the bead 21 can be inserted into the internal channel 7 of the cylindrical body 6 and then slide inside the latter while remaining in contact with the wall delimiting said internal channel 7.

[0033] The actuating cable 4 has a constant diameter and ends with an enlarged head 23. This actuating cable 4 is connected to the actuating housing 5, by means of an insertion of the enlarged head 23 into the internal channel 17 of the rod 16, said actuating cable passing through the first tube 22 of the rod 16 and into the second tube 12 of the cylindrical body 6 of the end housing 5, said two tubes 12, 22 being in perfect continuity with each other.

[0034] Referring to [Fig. 6], the downstream part 3 of an actuation system 1 according to the invention comprises an actuation part 24 which is fixed to one end of the actuation cable 4, a movement of said actuation cable 4 generating a movement of the actuation part 24 with the same amplitude. The movement of the actuation part 24 will cause a rotation of a driving part 25 which will then activate or deactivate the parking function of the vehicle depending on the direction of movement of the actuation cable 4. It should be noted that the actuation cable 4 is associated with a pre-stressed return element placed in a case 30 surrounding said actuation cable 4. This pre-stressed return element, which may for example be a spring, tends to exert a tensile force on the actuation cable 4, in a direction which opposes the direction of movement of the rod 16 passing from first position to second position.

[0035] Referring to Figures 2 and 4, the rod 16 which is placed in the internal channel 7 of the cylindrical body 6 of the end housing 5 can occupy a first position for which: -the first end of the rod 16 protrudes slightly from the activation nut 9, so that the rod 16 is very largely included in the internal channel 7 of the cylindrical body 6 of the end housing 5, -the first cylindrical section 18 of the rod 16 is screwed into the activation nut 9, -the first tube 22 of the rod 16 and the second tube 12 of the cylindrical body 6 of the end housing 5, are very close to each other, or even in contact with each other.

[0036] For this first position, the parking function is activated. To deactivate the parking function from this first position, the rod 16 must be placed in a second position, as illustrated in Figures 3 and 5.

[0037] To reach this second position from the first position, it is necessary to rotate the activation nut 9 around its axis of revolution, in a clockwise direction. In this way, said nut 9 pivots inside the internal channel 7 of the cylindrical body 6 of the actuating housing 5. This rotation of the activation nut 9 causes an upward translation of the rod 16, due to the presence of the first threaded section 18 of said rod 16 in said internal threaded channel 15 of the activation nut 9. This upward translation of the rod 16 causes a simultaneous displacement of the actuating wire 4 in the same direction and with the same amplitude, due to the insertion of the enlarged head 23 of said cable 4 into the internal channel 17 of the rod 16.This rotation of the activation nut 9 continues until the second section 19 of the rod 16 has completely reached said activation nut 9, as illustrated in [Fig. 3]. Since this second section 19 has a smooth external surface, continued rotation of the activation nut 9 in the same direction no longer has any effect on the movement of the rod 16, which is no longer engaged in said activation nut 9. The presence of this second smooth section 19 makes it possible to mark the second position of the rod 16 and to prevent a user from continuing to rotate the activation nut 9 by forcing it, which would risk damaging the actuation system 1. The actuation cable continued to move until the rod 16 reached the second position. When the rod 16 reached the second position, the parking function of the vehicle is deactivated. .

[0038] To move the rod 16 from the second position to the first position, it is sufficient to turn the activation nut 9 counterclockwise. Indeed, despite the presence of the second smooth section 19 of the rod 16 in the activation nut 9, the actuating cable 4 which is associated with the prestressed return element, will exert a tensile force on the rod 16 which will immediately be able to interact with the activation nut 9 by lowering itself.

Claims

Claims

1. An actuation system (1) comprising an end housing (5) having an internal through channel (7), an activation nut (9) having a threaded internal channel (15) and an elongated rod (16) having a threaded external surface (18), the activation nut (9) being placed at a first end (8) of the internal through channel (7) of the end housing (5) such that the axis of revolution of the activation nut (9) and the axis of revolution of the internal through channel (7) coincide, the elongated rod (16) passing through the activation nut (9) and extending into the internal channel (7) of the end housing (5), the rod (16) having a first end and a second end to which an actuation cable (4) is attached,and a rotation of the activation nut (9) causes a translational movement of the rod (16) along the internal channel (7) passing through allowing said rod (16) to pass: - from a first position for which the first end emerges slightly from the activation nut (9) towards the outside of the end housing (5), and the second end is positioned at a significant depth in the internal channel (7) of said end housing (5), - to a second position for which the first end emerges more significantly from the activation nut (9) than in the first position, towards the outside of the end housing (5), and the second end is positioned at a shallower depth in the internal channel (7) of the end housing (9) than in the first position, characterized in that the rod (16) has a section (19) whose external surface is smooth without any thread,and in that said section (19) is placed along the rod (16) in such a way that the second position of said rod (16) is reached when said section (19) has fully reached the internal threaded channel (15) of the activation nut (9).,

2. Actuation system according to claim 1, characterized in that the length of the smooth section (19) of the rod (16) is greater than or equal to the length of the internal threaded channel (15) of the activation nut (9)

3. Actuation system according to any one of claims 1 or 2, characterized in that the rod (16), the smooth section (19) and the internal threaded channel (15) of the activation nut (9) are cylindrical in shape, and in that the external diameter of the smooth section (19) of the rod (16) is less than the diameter of the internal threaded channel (15) of the activation nut (9) so that a clearance is created between them when the smooth section (19) has completely reached said internal threaded channel (15).

4. Actuation system according to any one of claims 1 to 3, characterized in that the rod (16) is hollow and the second end of said rod (16) has a first tube (22) of reduced size connecting an internal space (17) of said rod (16) to an external space (7) thereof, and in that a first end of the actuating cable (4) has an enlarged head (23) which is wider than said first tube (22), said actuating cable (4) being fixed to the second end of the rod (16) by means of an insertion of the enlarged head (23) of said cable (4) into the internal space (17) of said rod (16) and a passage of said cable (4) into said first tube (22).

5. Actuation system according to claim 4, characterized in that a second end (10) of the internal channel (7) of the end housing (5) has a second tube (12) having the same diameter as that of the first tube (22) and being in perfect continuity with said first tube (22), and in that the cable (4) emerges from the end housing (5) passing through said second tube (12).

6. Actuation system according to any one of claims 4 or 5, characterized in that a second end of the actuating cable (4) which is external to the end housing (5), is associated with a prestressed return element, so that the enlarged head (23) of said cable (4) remains in abutment against an internal wall delimiting the second end of the hollow rod (16).

7. An actuation system according to claim 4, characterized in that the second end of the actuation cable (4) is connected to an actuation part (24) which is set in motion by the actuation cable (4) moving together with the rod (16) in the end housing (5).

8. An actuation system according to any one of claims 1 to 7, characterized in that the first end of the rod (16) has an enlarged washer (26) which is in contact with the activation nut (9) when the rod (16) is in the first position.

9. An actuation system according to any one of claims 1 to 8, characterized in that the end housing (5) comprises fixing means intended for fixing said end housing (5) to a

10. external structural element. Vehicle comprising an actuation system according to any one of claims 1 to 9, characterized in that said actuation system (1) serves to control the parking function of the vehicle, so that in the first position, the rod (16) activates the parking function of the vehicle and in the second position it deactivates this function.

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