Actuator with position sensor

Abstract

An actuator (4) comprising: a body (8) at least partially containing a lever (12) operatively connected to motor means (16) and to actuating means (20) of a parking brake, said motor means (16) being configured to move the lever (12) along an operating stroke (24) at least from a first position (A) to a second position (B); an antenna (28) directly and integrally associated with the control rod (12), the antenna (28) being arranged inside the body (8); a position sensor (32) arranged on the printed circuit (36), housed inside the body (8) and facing the lever (12) and the antenna (28), the position sensor (32) being configured to detect the presence and position of the antenna (28).

Description

Technical Field

[0001] The invention relates to an actuator, for example a linear actuator, provided with a position sensor, in particular for use in a parking brake module in a motor vehicle. Background Art

[0002] In general, a parking brake module of a motor vehicle comprises at least one actuator, usually of the linear type and equipped with a rod, with an associated kinematic mechanism, capable of placing the gearbox in the “park” position and then unlocking it.

[0003] The parking configuration must comply with the vehicle's safety requirements, in particular it must comply with the vehicle's on-board diagnostics system (OBD); in other words, the vehicle's electronics must always be able to detect a possible malfunction of the parking function.

[0004] Prior art solutions involve indirect measurement or estimation of the parking module configuration; in other words, the known solutions involve the use of sensors on the operating kinematic mechanism of the linear actuator, for example on a gear or pinion of such a kinematic mechanism. The on-board electronics can therefore only estimate the position of the actuator and detect possible anomalies by checking the angular position of the kinematic mechanism.

[0005] However, this indirect check is not completely reliable and, in certain circumstances, may result in erroneous or untimely reporting of a possible fault, for example if the fault occurs downstream of the motion mechanism monitored by the sensor.

[0006] Furthermore, prior art solutions tend to be mechanically complex and thus result in relatively high production costs.

[0007] In short, prior art solutions are expensive and not always reliable because they are not compliant with the vehicle's on-board diagnostics system (OBD compliant). Summary of the invention

[0008] Therefore, it is necessary to address the above-mentioned shortcomings and limitations of the prior art.

[0009] The actuator according to claim 1 meets this need. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other features and advantages of the invention will become more readily apparent from the following description of preferred embodiments provided by way of non-limiting examples, in which:

[0011] Figure 1 shows a perspective view of an actuator in an assembled configuration according to one embodiment of the present invention;

[0012] Figure 2 Shows Figure 1 A perspective view of the actuator in an exploded configuration;

[0013] Figure 3 Shows Figure 1 A cross-sectional view of the actuator in an assembled configuration;

[0014] Figure 4 Shows Figure 1 A perspective view of an antenna and a position sensor of an actuator;

[0015] Figure 5 Shows from Figure 4 Viewed from the side of arrow V Figure 4 A side view of the antenna and position sensor in FIG.

[0016] Figure 6 , 7 , 8, 9 show side or plan views of the actuator of the relevant sensor in different operating positions;

[0017] Fig.10 A perspective view showing an antenna and a position sensor of an actuator according to another embodiment of the present invention;

[0018] Fig.11 Shows Fig.10 A side partial cross-sectional view of the antenna and position sensor in FIG.

[0019] Fig.12 Shows from Fig.11 Viewed from the side of arrow XII Fig.11 A side view of the antenna in FIG.

[0020] Fig.13 A perspective view showing an antenna and a position sensor of an actuator according to another embodiment of the present invention;

[0021] Fig.14 Shows Fig.13 A side partial cross-sectional view of the antenna and position sensor in FIG.

[0022] Fig.15 Shows from Fig.14 Viewed from the XV side of the arrow Fig.14 A side view of the antenna in FIG.

[0023] Elements or parts of elements common to the embodiments described below will be denoted by the same reference numerals. DETAILED DESCRIPTION

[0024] With reference to the above drawings, reference numeral 4 denotes an actuator applied to a parking brake module on a vehicle according to the present invention as a whole.

[0025] The actuator 4 comprises a body 8 at least partially containing a control lever 12 operatively connected to a motor arrangement 16 and to an actuating arrangement 20 of a parking brake (not shown).

[0026] Preferably, but not exclusively, the actuating device 20 is operatively connected to a parking brake of a motor vehicle. However, for the purposes of the present invention, the above applications are illustrative and not exhaustive.

[0027] The body 8 defines a containment volume 22 that is enclosed by a cover 26. For purposes of the present invention, the body 8 and cover 26 may have any shape and size; furthermore, they may be made of a variety of materials, including metals and plastic materials and combinations thereof.

[0028] The motor device 16 is configured to move the control rod 12 along the operating stroke 24 at least from the first position A to the second position B. Figure 8 ). The motor device 16 is preferably an electric motor, such as a DC motor.

[0029] It is worth noting that, for the purpose of the present invention, the operating stroke 24 is not necessarily a straight line, but may also be a curve, may include a broken line, or may even be an alternation of curved segments and straight segments.

[0030] For example, the control rod 12 is operatively connected to the motor assembly 16 via a kinematic mechanism, which may include a nut-screw type coupling, gears, idler gears, and the like.

[0031] Typically, the control rod 12 has a translational or rotational-translational movement, the latter being obtainable, for example, by a nut-screw type connection.

[0032] The actuator 4 comprises an antenna 28 directly and integrally associated with the control rod 12, said antenna being arranged inside the body 8, i.e. inside the accommodation volume 22. The antenna 28 can therefore directly provide position information (i.e. operating state information) of the control rod 12, rather than position information of the parts of the kinematic mechanism or of the motor device 16 itself configured to move the control rod 12. In other words, it is possible to obtain direct feedback on the position of the control rod 12 engaged with the actuation device 20, and therefore on the operating state of this control rod 12: this feedback explicitly provides the operating state of the actuation device 20 located downstream in the actuation chain starting from the motor device 16.

[0033] It is therefore possible to obtain absolutely reliable feedback on the operating state of the actuating device 20, instead of obtaining feedback on the operating state of the intermediate kinematic mechanism as in the solutions of the prior art. It is therefore obvious that the feedback obtainable from this configuration is essential for the operating diagnosis of the equipment arranged downstream of the actuating device 20.

[0034] The actuator 4 also comprises a position sensor 32, arranged for example on a printed circuit or PCB support 36, housed inside the body 8, i.e. in the housing compartment 22, and facing the control rod 12 and the antenna 28. The position sensor 32 is of active type and is powered by power supply means (not shown), typically DC power supply means.

[0035] The position sensor 32 is configured to detect the presence and position of the antenna 28 which, as shown, is directly and integrally associated with the control stick 12 .

[0036] According to a possible embodiment, the position sensor 32 is arranged on a PCB support 36 , for example parallel to the control rod 12 .

[0037] The size and location of the position sensor 32 are designed to cover and detect the position of the antenna 28 along the operating stroke 24, such as Figure 8 As shown, for example, it shows the antenna 28 at a first end-of-travel position A and a second end-of-travel position B, respectively.

[0038] Preferably, the antenna 28 is arranged inside the body 8, i.e. inside the accommodation volume 22, between the motor device 16 and the position sensor 32. Thus, the antenna 28 can always and immediately detect not only the position of the antenna 28 associated with the respective control lever 12, but also the presence of the antenna 28 associated with the respective control lever 12.

[0039] The system is therefore completely reliable and is able to detect immediately any anomaly downstream of the kinematic mechanism and therefore directly affecting the actuating device 20 whose operation and / or operating state must be monitored.

[0040] The anomaly refers both to the antenna 28 being disengaged from the corresponding control rod 12 (an event that will be immediately detected by the position sensor 32 which no longer senses the presence of the antenna 28 itself), and to an abnormal position of the antenna and the resulting improper operating configuration of the actuator 20.

[0041] Preferably, the antenna 28 is fixed to an inner end 52 of the control rod 12 , contained inside the body 8 , ie in the containment volume 22 , said inner end 52 being opposite and integral with an outer end 56 engaging said actuating means 20 .

[0042] According to a possible embodiment, the antenna 28 is fixed to the control rod 12 by interference (press fit) and / or gluing.

[0043] Preferably, the antenna 28 is keyed to a portion of the control rod 12 provided with an external thread 60; the thread thus allows the axial position of the antenna 28 relative to the control rod 12 to be adjusted by simply screwing the antenna 28 onto the threaded portion.

[0044] The external thread 60 also forms an axial undercut, i.e. it fixes the axial position of the antenna 28 relative to the control rod 12. For this purpose, a special stop can also be used to prevent a relative axial translation between the antenna 28 and the control rod, which would otherwise cause the position sensor 28 to erroneously read the position or operating state of the actuator 20.

[0045] As mentioned above, the control rod 12 may have any geometry and any relative actuation movement.

[0046] Preferably, but not exclusively, the control rod 12 has a main extension axis XX and is movable in an axial direction parallel to said main extension axis XX.

[0047] According to a possible implementation scheme ( Figures 1 to 9 ), the antenna 28 is symmetrical about the main extension axis XX.

[0048] According to a preferred embodiment, the antenna 28 is arranged coaxially with the control rod 12. Coaxial arrangement means that at least one portion 27 for fixing the antenna 28 to the control rod 12 is coaxial with the control rod 12 itself.

[0049] Preferably, the antenna 28 is a ring at least partially made of metal and coaxial with the control rod 12. Preferably, the antenna 28 is a single ring, manufactured in one piece, coaxially keyed to the control rod 12.

[0050] Preferably, the antenna 28 is directly associated with the control rod 12 ring.

[0051] The ring (e.g. The control rod 12 preferably comprises a plurality of radial teeth 64 which are separated from each other by grooves 68 and which are preferably provided with an end edge 72 in the shape of an arc; the radial teeth 64 thus engage with the external thread 60 of the control rod 12 and are screwed thereon.

[0052] As shown in the figure, the ring can be axisymmetric with respect to the main extension axis XX of the control rod 12 ( Figures 1 to 9 ). In this axisymmetric configuration, the angular orientation of the rings is not important.

[0053] It is also possible to provide an asymmetric loop as antenna 28, e.g. Figures 10 to 15In such an embodiment, the asymmetric ring has a precise angular orientation relative to the control rod 12. This orientation is obtained, for example, by a form coupling between the control rod and the fixed portion 27 of the ring. For example, this form coupling comprises a flat piece 29 made on the control rod 12, which is coupled to a flat seat 30 obtained on the ring.

[0054] According to a possible embodiment, the antenna 28 comprises a cylindrical support 44 to which a metal portion 48 is applied in the form of a metal foil, folded and applied, for example, by gluing. The metal foil 48 can also be applied as a metal coating, which can be obtained in various ways, including by PVD and / or CVD. In general, the metal portion can have any shape and thickness and can be applied to the control rod by gluing, interlocking, undercutting, welding, CVD, PVD, etc.

[0055] In general, said antenna 28 preferably has a cylindrical shape around said main extension axis XX, with a radius R greater than the distance or gap G from the position sensor 32 .

[0056] The cylindrical shape is particularly useful when the operating travel 24 of the control lever 12 and of the antenna 28 connected thereto is of the rotational-translational type. In fact, due to the axial symmetry of the antenna 28, the risk of the position sensor 32 taking unreliable readings based on the actual rotation angle of the antenna 28 during the operating travel 24 is avoided.

[0057] Preferably, the antenna 28 has an axial thickness T parallel to the main extension axis XX which is greater than or equal to the gap G from the position sensor 32 . Such a dimensioning always ensures that the position sensor 32 detects the antenna 28 correctly.

[0058] It can be understood from the above description that the present invention can overcome the shortcomings existing in the prior art.

[0059] In particular, the linear actuator according to the invention is particularly reliable since it directly measures the position of the end part which engages with the parking mechanism.

[0060] There is therefore no indirect estimation of the actuator configuration as in prior art solutions, but rather a direct measurement of the position of the final component of the kinematic mechanism engaging or disengaging the parking function.

[0061] Furthermore, any disengagement of the antenna from the associated control lever is immediately detected by a position sensor located near the antenna.

[0062] The actuator is also particularly simple and cost-effective to manufacture and assemble.

[0063] In fact, the antenna can be made using a very simple metal "Grifax" ring which is cost effective and easily available in the market.

[0064] The assembly step is also particularly simple and cost-effective, since the "Grifax" ring or generally the cylindrical antenna can be keyed immediately to the control rod. The antenna is thus self-supporting, since, by virtue of its geometry, it is automatically supported by the control rod; in fact, since the antenna is mounted coaxially to the control rod, it forms a radial undercut with respect to the control rod itself, thereby preventing it from detaching. As described above, in the event of a break or detachment, the antenna is separated from the control rod and the position sensor immediately detects the movement of the antenna away from the control rod.

[0065] Thus, unlike prior art solutions, the solution according to the invention is fully "OBD compliant".

[0066] Furthermore, the use of a ring mounted directly on the control rod and screwed on also makes it possible to change the axial position of the antenna relative to the control rod and thus to change the axial position of the antenna relative to different positions of the position sensor. In other words, the end-of-travel position can be changed by simply changing the axial position of the antenna relative to the control rod without having to manufacture a dedicated component.

[0067] Those skilled in the art may make several modifications and variations to the above solutions.

[0068] The scope of protection of the present invention is defined by the following claims. Reference numerals list 4: Actuator 8: Main body 12: Control rod 16: Motor device 20: Actuator 22: Accommodation volume 24: Operational Stroke 26: Cover 27: Fixed position 28: Antenna 29: Flat pieces 30: Flat support 32: Position sensor 36: Printed circuit or PCB bracket 44: Cylindrical support 48: Metal part 52: Inner end 56: Outer end 60: External thread 64: Radial teeth 68: Groove 72: End edge A: First position B: Second position A: Radius G: Gap T: Axial thickness XX: Main extension axis

Claims

1. An actuator (4), wherein include: - a body (8) at least partially containing a control lever (12) operatively connected to a motor device (16) and to an actuating device (20) of a parking brake, the motor device (16) being configured to move the control lever (12) along an operating stroke (24) at least from a first position (A) to a second position (B), - an antenna (28) directly and integrally associated with the control rod (12), the antenna (28) being arranged inside the body (8), - a position sensor (32) arranged on a printed circuit (36), housed inside the body (8) and facing the control rod (12) and the antenna (28), the position sensor (32) being configured to detect the presence and position of the antenna (28).

2. The actuator (4) according to claim 1, in, The control rod (12) has a main extension axis (XX) and is movable in an axial direction parallel to the main extension axis (XX).

3. The actuator (4) according to claim 2, in, The antenna (28) is axisymmetric about the main extension axis (XX).

4. An actuator (4) according to any one of claims 1 to 3, in, The antenna (28) is arranged coaxially with the control rod (12).

5. Actuator (4) according to any one of claims 1 to 4, in, The antenna (28) is a ring at least partially made of metal and coaxial with the control rod (12).

6. Actuator (4) according to any one of claims 1 to 5, in, The antenna (28) is fixed to the control rod (12) by interference (press fit) and / or bonding.

7. An actuator (4) according to any one of claims 1 to 6, in, The antenna (28) is keyed and screwed onto a portion of the control rod (12) provided with an external thread (60).

8. Actuator (4) according to any one of claims 1 to 7, in, The antenna (28) is a ring directly associated with the control rod (12), for example ring.

9. The actuator (4) according to claim 8, in, The ring comprises a plurality of radial teeth (64) separated from one another by grooves (68) and provided with an end edge (72) in the shape of an arc of a circle in order to be screwed onto the external thread (60) of the control rod (12).

10. Actuator (4) according to claim 8 or 9, in, The ring is axisymmetrical about the main extension axis (XX) of the control rod (12).

11. Actuator (4) according to claim 8 or 9, in, The ring is axisymmetric and provides a specific angular orientation between the ring and the control rod (12), which is obtained by a form coupling between a flat piece (29) made on the control rod (12) and a flat seat (30) obtained on the ring to which it is coupled.

12. Actuator (4) according to any one of claims 1 to 11, in, The antenna (28) comprises a cylindrical support (44) on which a metal portion (48) is applied.

13. Actuator (4) according to claim 12, in, The metal part includes a metal foil (48) and / or a metal coating applied by metal layer, bonding, interlocking, undercutting, welding, CVD, PVD, etc.

14. Actuator (4) according to any one of claims 1 to 13, in, The position sensor (32) is arranged on a printed circuit (36) parallel to the control rod (12).

15. Actuator (4) according to any one of claims 1 to 14, in, The antenna (28) has a cylindrical shape around the main extension axis (XX), with a radius (R) greater than the distance or gap (G) from the position sensor (32).

16. Actuator (4) according to any one of claims 1 to 15, in, The position sensor (32) is sized and positioned to cover and detect the position of the antenna (28) along the operating stroke (24).

17. Actuator (4) according to any one of claims 1 to 16, in, The control rod (12) has rotational and translational motion.

18. Actuator (4) according to any one of claims 1 to 17, in, The antenna (28) is arranged inside the body (8) between the motor device (16) and the position sensor (32).

19. Actuator (4) according to any one of claims 1 to 18, in, The antenna (28) is fixed to an inner end (52) of the control rod (12) and contained inside the body (8), the inner end (52) being opposite and integral with an outer end (56) engaged with the actuating device (20).

20. Actuator (4) according to any one of claims 1 to 19, in, The antenna (28) has an axial thickness (T) parallel to the main extension axis (XX) that is greater than or equal to a gap (G) from the position sensor (32).

21. A parking brake comprising an actuator (4) according to any one of claims 1 to 20.

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