Parking brake system and vehicle comprising such a parking brake system

Abstract

The parking brake system comprises at least one park lock device (20) including a dog clutch part (30), rotatable with a wheel (6) around a rotation axis (A30), with respect to a chassis (4) of a vehicle, and a slider dog (40), mounted on the chassis and slidable (A2) along an axis (A50) parallel to the rotation axis. The park lock device (20) is bi-stable and non-reversible. The dog clutch part (30) is equipped with teeth (362. The slider dog (40) comprises a first component (42), equipped with teeth (462) that complement those (362) of the dog clutch, and a second component (44), fixed in rotation, around the rotation axis (A30), with respect to the chassis (4). The first component (42) of the slider dog (40) as a degree of freedom in rotation, around the rotation axis (A30), with respect to the second component (44).

Description

PARKING BRAKE SYSTEM AND VEHICLE COMPRISING SUCH A PARKING BRAKE SYSTEMTECHNICAL FIELD

[0001] The disclosure relates generally to parking brakes. In particular aspects, the disclosure relates to a parking brake system for a vehicle and to a vehicle including, amongst others, such a parking brake system. The disclosure can be applied to heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle.BACKGROUND

[0002] In the field of automotive vehicles, friction brake technology is widely used to immobilize a vehicle on the ground. The friction brake technology makes use of electropneumatic systems using air under pressure as working fluid. An electro-pneumatic system includes spring brake cylinders. When the spring brake cylinders are pressurized with compressed air, a spring is compressed and does not apply load on brake pads, so that the park brake is released. When the spring brake cylinders are vented, a spring pushes the brake pads that apply load on a brake disc and the vehicle is immobilized due to friction. Such an electro-pneumatic parking brake system is bulky and requires some space to be installed, as well as high pneumatic energy to release the park brake. The friction brake technology also makes use of an electro mechanic brake, which requires energy to apply the parking brake effort, to reach enough friction for immobilization, before locking it. This implies that the vehicle shall always carry a battery for the electric energy required to apply the park brake at standstill.SUMMARY

[0003] According to a first aspect of the disclosure, a parking brake system for a vehicle includes a chassis and at least one wheel rotatable with respect to the chassis, whereas the parking brake system comprises at least one park lock device including a dog clutch part, rotatable with the wheel around a rotation axis, with respect to the chassis, and a slider dog,mounted on the chassis and slidable along an axis parallel to the rotation axis. The park lock device is bi-stable and non-reversible. The dog clutch part is equipped with teeth. The slider dog comprises a first component, equipped with teeth that complement those of the dog clutch, and a second component, fixed in rotation, around the rotation axis, with respect to the chassis. The first component of the slider dog as a degree of freedom in rotation, around the rotation axis, with respect to the second component.

[0004] The first aspect of the disclosure may seek to improve the efficiency of the parking brake system. A technical benefit may include the compactness of the parking brake function, since the park lock device is smaller and requires less brake power / energy than a pneumatic system, to apply and / or release the parking brakes. This saves hardware, space and energy. Another technical benefit may include a low risk of unintentional deactivation of the parking brake system, due to the fact that the park lock device is bi-stable. In addition, since the park lock device is non-reversible, there is no risk of a torque exerted on the wheel being transferred to any component of the vehicle other than the dog clutch part and the slider dog. Moreover, the degree of freedom between the first and second components of the slider dog facilitates engagement between the teeth of the dog clutch part and the teeth of the first component of the slider dog.

[0005] In the meaning of the present disclosure, a non-reversible device transmits movement from its input side to its output side and prevents a transmission of movement from its output side to its input side.

[0006] Optionally in some examples, including in at least one preferred example, the first component of the slider dog is urged, by at least one elastic member, toward at least one predetermined position with respect to the second component of the slider dog. A technical benefit may include that the first component remains by default in its predetermined position and does not risk oscillating nor making noise when the vehicle is moving.

[0007] Optionally in some examples, including in at least one preferred example, the elastic member is a coil spring or a leaf spring. A technical benefit may include a simple, reliable and robust construction of the elastic return function.

[0008] Optionally in some examples, including in at least one preferred example, the elastic member is a block of elastomer. A technical benefit may include another simple, reliable and robust construction of the elastic return function.

[0009] Optionally in some examples, including in at least one preferred example, the parking brake system includes several elastic members regularly distributed around the rotation axis.A technical benefit may include that the elastic effort exerted by the elastic members is balanced around the rotation axis.

[0010] Optionally in some examples, including in at least one preferred example, each elastic member is interposed, radially with respect to the rotation axis, between the first component of the slider dog and the second component of the slider dog. A technical benefit may include a protection of the elastic member(s) against the environment and against pollution, together with a precise definition of the effort exerted by each elastic member.

[0011] Optionally in some examples, including in at least one preferred example, each elastic member is housed in a cavity defined, in a direction radial to the rotation axis, between an outer radial surface of the first component of the slider dog and an inner radial surface of the second component of the slider dog and, in a direction ortho-radial to the rotation axis, between an outer spline of the first element of the slider dog and an inner spline of the second element of the slider dog. A technical benefit may include that each elastic member is mechanically protected and interacts directly with the splines of the first and second components of the slider dog.

[0012] Optionally in some examples, including in at least one preferred example, the first component of the slider dog is housed within a cavity of the second component of the slider dog. A technical benefit may include a compact construction of the slider dog.

[0013] Optionally in some examples, including in at least one preferred example, wherein edges of the teeth of the first component of the slider dog are configured to engage with edges of the teeth of the dog clutch. A technical benefit may include a facilitated engagement sequence between the teeth of the dog clutch part and the teeth of the slider dog.

[0014] Optionally in some examples, including in at least one preferred example, an edge of a tooth of the dog clutch and / or an edge of a tooth of the first component of the slider dog is chamfered or rounded. A technical benefit may include a further facilitated engagement sequence between the teeth of the dog clutch part and the teeth of the slider dog.

[0015] Optionally in some examples, including in at least one preferred example, an edge of a tooth of the dog clutch and an edge of a tooth of the first component of the slider dog include respective parallel inclined surfaces oriented, with respect to the rotation axis, in opposite directions and wherein the inclined surfaces can slide one against the other. A technical benefit may include a direct cooperation between the teeth of the dog clutch part and the teeth of the slider dog, upon engagement of these teeth.

[0016] Optionally in some examples, including in at least one preferred example, an angular amplitude of a rotational movement of the first component of the slider dog, around the rotation axis, with respect to the second component of the slider dog is at least as large as an angular pitch of the teeth of the dog clutch part. A technical benefit may include that the teeth of the dog clutch part and the teeth of the slider dog are permanently in a position do engage.

[0017] Optionally in some examples, including in at least one preferred example, the angular amplitude is between 5° and 30°, preferably between 10° and 20A technical benefit may include an efficient and compact construction of the slider dog.

[0018] Optionally in some examples, including in at least one preferred example, a lead screw assembly slides the slider dog along the direction parallel to the rotation axis. A technical benefit may include a compact, simple and reliable way of making the park lock device bi-stable and / or non-reversible.

[0019] Optionally in some examples, including in at least one preferred example, a bi-stable solenoid slides the slider dog along the direction parallel to the rotation axis. A technical benefit may include another compact, simple and reliable way of making the park lock device bi-stable and / or non-reversible.

[0020] Optionally in some examples, including in at least one preferred example, a bi-stable magnetic clutch slides the slider dog along the direction parallel to the rotation axis. A technical benefit may include another compact, simple and reliable way of making the park lock device bi-stable and / or non-reversible.

[0021] According to a second aspect of the disclosure, the invention relates to a vehicle including a chassis, at least one wheel rotatable with respect to the chassis and a parking brake system as previously described. The second aspect of the disclosure may seek to provide a vehicle capable of being efficiently parked. A technical benefit may include the compactness of the parking brake function. Another technical benefit may include a low risk of unintentional deactivation of the parking brake system. In addition, since the park lock device is non-reversible, there is no risk of a torque exerted on the wheel being transferred to any component of the vehicle other than the dog clutch part and the slider dog. Moreover, the degree of freedom between the first and second components of the slider dog facilitates engagement between the teeth of the dog clutch part and the teeth of the first component of the slider dog.

[0022] Optionally in some examples, including in at least one preferred example, the dog clutch is fast in rotation, around the rotation axis, with the wheel, wherein the rotation axis issuperimposed with a rotation axis of the wheel and the park lock device is configured to selectively lock one wheel. A technical benefit may include a direct interaction between the park lock device and the wheel.

[0023] Optionally in some examples, including in at least one preferred example, the dog clutch part is integral with a central shaft of the wheel and / or with a service brake disc. A technical benefit may include a simple and reliable construction of the dog clutch part.

[0024] Optionally in some examples, including in at least one preferred example, the dog clutch is fast in rotation with an entry shaft of a differential of the vehicle, wherein the rotation axis is superimposed with a rotation axis of the entry shaft and the park lock device is configured to selectively lock at least two wheels driven by the differential. A technical benefit may include a possibility to brake two wheels with a single park lock device.

[0025] The disclosed aspects, examples (including any preferred examples), and / or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Examples are described in more detail below with reference to the appended drawings.

[0027] FIG. 1 is an exemplary view of two vehicle according to an example;

[0028] FIG. 2 shows, on several inserts A) to D), some schematic representations of a park lock device, which belongs to a park brake system of one of the vehicles of figure 1;

[0029] FIG. 3 shows different views of a wheel hub including a dog clutch part;

[0030] FIG. 4 shows different views of a slider dog; and

[0031] FIG. 5 shows, in perspective and on several inserts A) to F), different partial views of the interaction between the dog clutch part of figure 3 and the slider dog of figure 4.DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0032] Figure 1 shows on insert A) a vehicle 2 according to an example, which includes a chassis 4, two front wheels 6A and two rear wheels 6B. In the present text, 6 denotes one of the wheels of the vehicle 2, which can be a front wheel 6A or a rear wheel 6B.

[0033] A motor assembly 8 is mounted on the chassis 4. It is connected, by a drive shaft 10, to a differential 12, which drives the two rear wheels 6B of the vehicle 2.

[0034] In the non-limiting example of the figures, the vehicle 2 is a truck.

[0035] Arrow Al shows the forward direction of movement of the vehicle 2 on figure 1.

[0036] The vehicle 2 includes a parking brake system 16, which has the function of keeping the vehicle 2 stationary on the ground when the parking brake system 16 is applied.

[0037] In the example of insert A) of figure 1, the parking brake system 16 includes four park lock devices 20.

[0038] The number of park lock devices 20 is not limitative. It can be between 1 and the number of wheels 6 of the vehicle 2.

[0039] One such park lock device 20 is represented on figures 2 to 5.

[0040] The park lock device 20 includes a dog clutch part 30.

[0041] Advantageously, the dog clutch part 30 is made in one piece of metal and includes a service brake disc 32, a wheel shaft 34 and a toothed portion 36 provided with outer peripheral teeth 362.

[0042] Alternatively, the toothed portion 36 is integral with the disc brake 32 only, or with the wheel shaft 34 only. According to another alternative, the toothed portion 36 is a structural part on its own, assembled with parts 32 and / or 34.

[0043] A30 denotes a longitudinal axis of a dog clutch part 30 which is superimposed with a rotation axis A6 of the wheel 6 to which the dog clutch part 30 is attached. Axis A30 is a rotation axis of the dog clutch part 30.

[0044] Each tooth 362 extends radially outwardly, with respect to the rotation axis A30, from a cylindrical base surface 364 centered on the rotation axis A30.

[0045] Opposite to the disc brake 32, each tooth 362 has a chamfered edge 366, with a front surface 368 inclined, with respect to the rotation axis A30, in a first direction.

[0046] Advantageously, all inclined surfaces 368 of all teeth 362 have the same orientation with respect to the rotation axis A30.

[0047] In a non-represented variant, the edge 366 of each tooth 362 is rounded.

[0048] a denotes an angular pitch, around the rotation axis A30, of the teeth 362.

[0049] The park lock device 20 also includes a slider dog 40, centered on a longitudinal axis A40 superimposed with the rotation axes A30 and A6 in mounted configuration of the park lock device 20.

[0050] The slider dog 40 is mounted within a slide 50 fast with the frame 4 of the vehicle 2. The slide 50 extends along a longitudinal axis A50 superimposed with the longitudinal axis A40 in mounted configuration of the slider dog 40 within the slide 50.

[0051] Preferably, as in the example of the figures, the longitudinal axis A50 is superimposed with the rotation axis A30, when the park lock device 20 is in mounted configuration.

[0052] According to a non-represented variant, the longitudinal axis A50 is not superimposed with the longitudinal axis A40, nor the rotation axis A30, but parallel and offset with regard to these axes.

[0053] Advantageously, the slide 50 is rigidly and permanently mounted on the chassis 4, e.g. by welding.

[0054] Alternatively, the slide 50 can be rigidly mounted on the chassis 4 in a reversible way, e.g. via screws.

[0055] The slide 50 defines a cavity C52, centered on the longitudinal axis A50, for the reception of the slider dog 40. In the example of the figures, this cavity C52 is a through opening. Alternatively, this cavity C52 might be a blind hole, with an end wall provided with an opening for the passage of a drive member of the slider dog 40.

[0056] The cavity C52 is provided with inner splines 54, parallel to the longitudinal axis A50.

[0057] On the other hand, the slider dog 40 includes a first component 42 and a second component 44.

[0058] Each component 42 and 44 extends along a respective longitudinal axis A42, respectively A44. In mounted configuration of the slider dog 40, both longitudinal axes A42 and A44 are superimposed with the longitudinal axis A40.

[0059] The first component 42 defines a cavity C420 for the partial reception of the dog clutch part 30, more precisely for the reception of the toothed portion 36.

[0060] As shown on figure 4, the first component 42 is mounted within a cavity C440 of the second component 44.

[0061] The first component 42 is provided with a toothed portion 46, which includes several teeth 462 extending radially towards the longitudinal axis A40, from a base surface 464, which forms a radial inner surface of the first component 42.

[0062] The teeth 462 are complementary to the teeth 362. In other words, they can come in meshing engagement.

[0063] Advantageously the number of teeth 462 equals the number of teeth 362.

[0064] Each tooth 462 has a chamfered edge 466 with an inclined surface 468 oriented, with respect to the longitudinal axis A40, thus with respect to the rotation axis A30 in mounted configuration of the park lock device 20, in a direction opposite to the inclined surface 368 of the chamfered edge 366 of a tooth 362. In other words, when they face each other, the inclined surface 368 of a tooth 362 and the inclined surface 468 of a tooth 462 are parallel, so that they can slide one against the other.

[0065] Advantageously, all inclined surfaces 468 of all teeth 462 have the same orientation with respect to the longitudinal axis A40.

[0066] In the case where, the edge 366 of each tooth 362 is rounded, the edge 466 of each tooth 462 is rounded.

[0067] P denotes the angular pitch between two adjacent teeth 462, around the longitudinal axis A40.

[0068] Advantageously, the angular pitches a and P are equal.

[0069] The first component 42 is equipped with outer splines 422 regularly distributed around the longitudinal axis A40.

[0070] The second component 44 is provided with inner splines 442 regularly distributed around the longitudinal axis A40 and with outer splines 444 also regularly distributed around the longitudinal axis A40.

[0071] The number of outer splines 422 is advantageously equal to the number of inner splines 442.

[0072] The dimensions and angular pitch of the outer splines 444 are chosen to allow the second component 44 to slide within the cavity 52 with the splines 444 in engagement with the splines 54 of the slide 50.

[0073] Preferably, the second component 44 can slide within the cavity 52, along the longitudinal axis A50, without any possibility of rotation around this axis.

[0074] On the other hand, the distribution of the outer splines 422 of the first component 42 and of the inner splines 442 of the second component 44 is such that, when the first component is received within the cavity C440, the first component 42 can rotate around the longitudinal axis A40 with respect to the second component 44, with a limited angular amplitude y, defined by the cooperation of the splines 422 and 442.

[0075] In other words, the longitudinal axis A40 is a rotation axis for the first component 42 with the cavity C440 of the second component 44.

[0076] Thus, there exist a degree of freedom in rotation of the first component 42 with respect to the second component 44, around the longitudinal axes A40 and A50, thus with respect to the rotation axis A30 of the dog clutch, when the slider dog 40 is mounted within the slide 50 and when the dog clutch part 30 is received within the inner cavity C420 of the first component 42.

[0077] With this respect, as visible on figure 4, the respective bottom walls 421 and 441 of the cavities C420 and C440 are provided with a through opening 423, respectively 443, for the passage of the wheel shaft 34, when the toothed portions 36 and 46 are aligned, along the axes A6, A30 and A40.

[0078] Advantageously, an elastic member 48 is installed between each outer spline 422 and an adjacent inner spline 442. Thus, the elastic member are regularly distributed around the rotation axis A30, which implies that the combined effort exerted by the set of elastic members 48 is balanced around this axis.

[0079] In the example of the figures, each elastic member 48 is a coil spring.

[0080] Only a few coil springs 48 are represented on figures 4 and 5, for the sake of simplicity. However, the number of coil springs 48 can be chosen by the designer of the park lock device 20 between one and the number of outer splines 422, which is the case in the example if the figures.

[0081] The or each coil spring 48 is configured to urge, that to elastically push, the first component 42, in rotation around the longitudinal axis A40, thus around the rotation axis A30, towards a first predetermined position, where each outer spline 422 is in abutment against an inner spline 442 by its side opposite to the coil spring 48. Thus, by default, the first component 42 received within the cavity C440 is urged in the first predetermined position, where it stays, in particular when the toothed portions 36 and 46 are not in engagement. This avoids that the first component oscillates and possibly generates noise when the vehicle 2 is moving and / or when the parking brake system 16 is not actuated.

[0082] Each coil spring 48 is accommodated in a respective cavity C48 defined, in a direction radial to the longitudinal axis A40, between an outer radial surface S42 of the first component 42 and an inner radial surface S44 of the second component 44. In a direction ortho-radial to the longitudinal axis A40, each cavity C48 is defined between an outer spline 422 of the first element 42 and an inner spline 442 of the second element 44.

[0083] In particular, each spring 48 is interposed, radially with respect to the rotation axis A30, between the first component 42 and the second component 44.

[0084] On figure 5, inserts A), C), D) and E) show partial perspective views of the park lock device 20, in different configurations, when the slider dog 40 is translated in the direction of an arrow A2, for engaging with the dog clutch part 30. Inserts B) and H) of figure 5 show partial local sections, in a direction parallel to axes A30, A40 and A50, of the dog clutch, respectively in the configuration of inserts A) and E).

[0085] As visible on insert B) and H) of figure 5, some recesses 422A and 442A are advantageously provided laterally, respectively on the outer splines 422 and inner splines 442, in order to accommodate the extremities of each spring 48. This avoids losing these springs when the first component 42 is in its first predetermined position and the cavities have a maximum dimension in a direction ortho-radial to the rotation axis A30, so that the springs are not highly compressed between the splines 422 and 442 in this direction.

[0086] According to a non-represented variant, a leaf spring can be used to form an elastic member, instead of the coil spring 48, with the same function.

[0087] Advantageously, the coil or leaf spring is made of metal, which guarantees its lifetime during the use of the vehicle.

[0088] According to a second non-represented variant, an elastic member in form of a block of elastomer can be used, instead of the coil spring 48, with the same function.

[0089] A drive mechanism 60 is used to translate the slider dog 40 along the longitudinal axis A50 of the slide 50, in the two directions of arrow A2 on insert A) of figure 2. The first direction, to the left of figure 2 and shown on figure 5, corresponds to an engagement sequence of the toothed portions 36 and 46. The second direction, to the right of figure 2, correspond to a disengagement of the toothed portions 36 and 46.

[0090] This drive mechanism 60 includes an electric motor 62 whose output shaft 622 is rotatably connected to a screw 64 received within a non-rotatable nut 66, so that a rotation of the output shaft 622 of the electric motor 62 is converted, by the lead screw assembly made of parts 64 and 66, into a translation of the nut 66 along the longitudinal axis A50, in one of the directions of double arrow A2. The nut 66 is connected to the slider dog and drives it in the two directions of arrow A2 on figure 2.

[0091] By a proper choice of the angle of the respective threads of the screw 64 and the nut 66, the drive mechanism 60 is non-reversible. In addition, the electric motor is, by nature, bi-stable, since it does not rotate its output shaft 622 when it is not supplied with electric power. The park lock device 20 is thus bi-stable and non-reversible.

[0092] In an alternative embodiment, partly represented on insert D) of figure 2, the drive mechanism 60 includes a bi-stable linear actuator 68, which can take the form of a bi-stable solenoid or a bi-stable magnetic clutch. Such a linear actuator is non-reversible. With this construction, the drive mechanism 60, thus the park lock device 20, is also bi-stable and non-reversible.

[0093] When the vehicle 2 is moving on the ground or has just come to a standstill, the park brake system 16 is not actuated and each park lock device 20 is in a disengaged configuration represented on insert A) of figure 2 and inserts A) and B) of figure 5. In this configuration, the dog clutch part 30 and the slider dog 40 are offset along the rotation axis A30, so that the toothed parts 36 and 46 do not mesh. The springs 48 keep the first component 42 in its first predetermined position, whereas the toothed portion 36 can take any orientation around the rotation axis A30, due to the rotation of the wheel 6 around its rotation axis A6.

[0094] When the driver actuates the park brake system 16, the drive mechanism 60 slides the slider dog 40 towards the dog clutch part 30. The two toothed portions 36 and 46 get closer to each other, as shown on insert B) of figure 5.

[0095] On figures 2 and 5, arrow A2 shows the translational movement of the slider dog 40 under the action of the drive mechanism 60, for the change between the configurations of inserts A) to F) of figure 2.

[0096] In the configuration of insert C) of figure 5, the chamfered edges 366 of the teeth 362 engage in an interspace between two adjacent teeth 462 and the chamfered edges 466 of the teeth 462 engage in an interspace between two adjacent teeth 362. This occurs up to a point where the inclined surfaces 368 and 468 of the chamfered edges 366 and 466 come in sliding contact with each other, which corresponds to the configuration of insert D) of figure 5.

[0097] From the configuration of insert D) of figure 5, the translational movement of the slider dog 40 in the direction of arrow A2 induces that the first component 42 rotates around the rotation axis A6 in the direction of arrow A3, against the action of the springs 48. This rotation goes on up to an angular position of the first component 42 where each chamfered edge 466 has bypassed the inclined surface 368 of the facing tooth 362, such that each tooth 462 can be fully engaged between two adjacent teeth 362 of the toothed portion 36, which corresponds to the configuration of inserts E) and F) on figure 5.

[0098] When the first component 42 rotates in the direction of arrow A3, between the configuration of inserts A) and B), on the one hand, and the configuration of inserts E) and F), on the other hand, each coil spring 48 is progressively compressed between two adjacent splines 422 and 442. Thus, the set of coil springs 48 keeps the first component 42 within a second predetermined position which is defined by a lateral surface contact between the teeth 362 and 462.

[0099] The sequence of movement represented on figure 5 brings the park lock device 20 from the configuration represented on insert B) of figure 2, where the spring 48 is slightly compressed, to the configuration represented on insert C) on this figure, where each spring 48 is intensively compressed.

[0100] y denotes the angular amplitude, that is the maximum angular span, of the rotational movement of the first component 42 with respect to the second component 44 around the rotation axis A30. This angular amplitude y is at least as large as the angular pitch a of the teeth 362 of the dog clutch part 30. This guarantees that it is always possible to insert the teeth 462 between the teeth 362, irrespective of the angular orientation of the toothed portion 36 in the configuration of inserts A) and B) of figures 2 and 5.

[0101] Advantageously, the angular amplitude y is chosen between 5° and 30°, preferably between 10° and 20°.

[0102] Advantageously, the rollback effect, that is the rolling distance that can be covered by the vehicle 2 once the park lock device 20 has been applied, is decreased by increasing the number of teeth 362 and / or 462, that is by decreasing the angular pitch a and / or p.

[0103] When it is necessary to deactivate the parking brake system, the drive mechanism is actuated to move the slider dog in a direction opposite to arrow A2 on figure 5, that is in the right direction of arrow A2 on figure 2, so that the toothed portion 46 is gradually removed from engagement with the toothed portion 36, by a translation along the longitudinal axis A40. At the end of this sequence, the two toothed portions are offset along the rotation axis A30 and the dog clutch part 30 can freely rotate around the rotation axis A30. Moreover, the elastic members 48 bring back the first component 42 into its first predetermined position.

[0104] The disclosure can be implemented with one park lock device 20 per wheel 6, as shown in insert A) of figure 1. In such a case, each park lock device 20 is configured to selectively lock one wheel 6 A, 6B.

[0105] Alternatively, and as shown on insert B) of figure 1, a park lock device 20 can be mounted with its dog clutch part 30 fast in rotation with the drive shaft 10, which forms anentry shaft for the differential 16. In such a case, the rotation axis A30 of the dog clutch part 30 of the park lock device 20 is superimposed with the rotation axis A10 of the entry shaft 10. Moreover, actuation of this park lock device 20 allows selectively locking in rotation the differential, thus the two rear wheels 6B of the vehicle 2 driven by the differential 12, in one operation.

[0106] If the differential 12 drives more than two wheels, e.g. four wheels, the park lock device can selectively lock in rotation more than two wheels.

[0107] According to a non-represented variant, the park lock devices 20 can be omitted at the level of the front wheels 6A of the vehicle 2.

[0108] The disclosure is represented on figure 1 with a vehicle having four wheels, two front wheels 6A and two rear wheels 6B, the rear wheels being driven by the motor assembly 8. Alternatively, all the wheels 6 of the vehicle 2 are driven by the motor assembly 8 and / or the number of wheels 6 can be different from four, e.g. equal to six or eight.

[0109] Example 1: A parking brake system 16 for a vehicle 2 including a chassis 4 and at least one wheel 6 rotatable with respect to the chassis, whereas the parking brake system comprises at least one park lock device 20 including a dog clutch part 30, rotatable with the wheel around a rotation axis A30, with respect to the chassis, and a slider dog 40, mounted on the chassis and slidable along an axis A50 parallel to the rotation axis; the park lock device 20 is bi-stable and non-reversible; the dog clutch part 30 is equipped with teeth 362; the slider dog 40 comprises a first component 42, equipped with teeth 462 that complement those of the dog clutch, and a second component 44, fixed in rotation, around the rotation axis A30, with respect to the chassis; the first component 42 of the slider dog 40 as a degree of freedom in rotation, around the rotation axis A30, with respect to the second component 44.

[0110] Example 2: The parking brake system of example 1, wherein the first component 42 of the slider dog 40 is urged, by at least one elastic member 48, toward at least one predetermined position with respect to the second component 44 of the slider dog 40.

[0111] Example 3: The parking brake system of example 2, wherein the elastic member 48 is a coil spring or a leaf spring.

[0112] Example 4: The parking brake of example 2, wherein the elastic member 48 is a block of elastomer.

[0113] Example 5: The parking brake system of one of examples 2 to 4, wherein it includes several elastic members 48 regularly distributed around the rotation axis.

[0114] Example 6: The parking brake system of one of examples 2 to 5, wherein each elastic member 48 is interposed, radially with respect to the rotation axis A30, between the first component 42 of the slider dog 40 and the second component 44 of the slider dog.

[0115] Example 7: The parking brake system according to example 6, wherein each elastic member 48 is housed in a cavity C48 defined, in a direction radial to the rotation axis A30, between an outer radial surface S42 of the first component 42 of the slider dog 40 and an inner radial surface S44 of the second component 44 of the slider dog and, in a direction ortho-radial to the rotation axis, between an outer spline 422 of the first element 42 of the slider dog and an inner spline 442 of the second element 44 of the slider dog.

[0116] Example 8: The parking brake system according to any of the preceding examples, wherein the first component 42 of the slider dog 40 is housed within a cavity C440 of the second component 44 of the slider dog.

[0117] Example 9: The parking brake system according to any of the preceding examples, wherein edges 466 of the teeth 462 of the first component 42 of the slider dog 40 are configured to engage with edges 366 of the teeth 362 of the dog clutch 30.

[0118] Example 10: The parking brake system according to example 9, wherein an edge 366 of a tooth 362 of the dog clutch 30 and / or an edge 466 of a tooth 462 of the first component 42 of the slider dog 40 is chamfered or rounded.

[0119] Example 11: The parking brake according to example 10, wherein an edge 366 of a tooth 362 of the dog clutch 30 and an edge 466 of a tooth 462 of the first component 42 of the slider dog 40 include respective parallel inclined surfaces 368, 468 oriented, with respect to the rotation axis A30, in opposite directions and wherein the inclined surfaces 368, 468 can slide one against the other.

[0120] Example 12: The parking brake system according to any of the preceding examples, wherein an angular amplitude y of a rotational movement of the first component 42 of the slider dog 40, around the rotation axis A30, with respect to the second component 44 of the slider dog is at least as large as an angular pitch a of the teeth 362 of the dog clutch part 30.

[0121] Example 13: The parking brake system according to example 12, wherein the angular amplitude y is between 5° and 30°, preferably between 10° and 20°.

[0122] Example 14: The parking brake system according to any of the preceding examples, wherein a lead screw assembly 34, 66 slides the slider dog 40 along the direction A50 parallel to the rotation axis A30.

[0123] Example 15: The parking brake system according to any of the preceding examples, wherein a bi-stable solenoid 68 slides the slider dog along the direction A50 parallel to the rotation axis A30.

[0124] Example 16: The parking brake system according to any of the preceding examples, wherein a bi-stable magnetic clutch 68 slides the slider dog along the direction A50 parallel to the rotation axis A30.

[0125] Example 17: A vehicle 2 including a chassis 4, at least one wheel 6 rotatable with respect to the chassis and a parking brake system according to any of the preceding examples.

[0126] Example 18: The vehicle according to example 17, wherein the dog clutch 30 is fast in rotation, around the rotation axis A30, with the wheel 6, wherein the rotation axis A30 is superimposed with a rotation axis A6 of the wheel and the park lock device 20 is configured to selectively lock one wheel 6 A, 6B.

[0127] Example 19: The vehicle of example 18, wherein the dog clutch part 20 is integral with a central shaft 34 of the wheel 6 and / or with a service brake disc 32.

[0128] Example 20: The vehicle of example 17, wherein the dog clutch is fast in rotation with an entry shaft 10 of a differential 12 of the vehicle 2, wherein the rotation axis A30 is superimposed with a rotation axis A10 of the entry shaft and the park lock device is configured to selectively lock at least two wheels 6B driven by the differential 12.

[0129] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0130] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0131] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0132] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0133] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

AMENDED CLAIMSreceived by the International Bureau on 23 December 2025 (23.12.2025) What is claimed is:

1. A parking brake system (16) for a vehicle (2) including a chassis (4) and at least one wheel (6) rotatable with respect to the chassis, whereinthe parking brake system comprises at least one park lock device (20) including o a dog clutch part (30), rotatable with the wheel around a rotation axis (A30), with respect to the chassis, ando a slider dog (40), mounted on the chassis and slidable along an axis (A50) parallel to the rotation axis;the park lock device (20) is bi-stable and non-reversible;the dog clutch part (30) is equipped with teeth (362);the slider dog (40) comprises a first component (42), equipped with teeth (462) that complement those of the dog clutch, and a second component (44), fixed in rotation, around the rotation axis (A30), with respect to the chassis; the first component (42) of the slider dog (40) as a degree of freedom in rotation, around the rotation axis (A30), with respect to the second component (44).

2. The parking brake system of claim 1, wherein the first component (42) of the slider dog (40) is urged, by at least one elastic member (48), toward at least one predetermined position with respect to the second component (44) of the slider dog (40).

3. The parking brake system of claim 2, wherein the elastic member (48) is a coil spring or a leaf spring.

4. The parking brake system of claim 2, wherein the elastic member (48) is a block of elastomer.

5. The parking brake system of one of claims 2 to 4, wherein it includes several elastic members (48) regularly distributed around the rotation axis.

6. The parking brake system of one of claims 2 to 5, wherein each elastic member (48) is interposed, radially with respect to the rotation axis (A30), between the first component (42) of the slider dog (40) and the second component (44) of the slider dog.

7. The parking brake system of claim 6, wherein each elastic member (48) is housed in a cavity (C48) defined, in a direction radial to the rotation axis (A30), between an outerradial surface (S42) of the first component (42) of the slider dog (40) and an inner radial surface (S44) of the second component (44) of the slider dog and, in a direction ortho-radial to the rotation axis, between an outer spline (422) of the first element (42) of the slider dog and an inner spline (442) of the second element (44) of the slider dog.

8. The parking brake system of one of the preceding claims, wherein the first component (42) of the slider dog (40) is housed within a cavity (C440) of the second component (44) of the slider dog.

9. The parking brake system of one of the preceding claims, wherein edges (466) of the teeth (462) of the first component (42) of the slider dog (40) are configured to engage with edges (366) of the teeth (362) of the dog clutch (30).

10. The parking brake system of claim 9, wherein an edge (366) of a tooth (362) of the dog clutch (30) and / or an edge (466) of a tooth (462) of the first component (42) of the slider dog (40) is chamfered or rounded.

11. The parking brake system of claim 10, wherein an edge (366) of a tooth (362) of the dog clutch (30) and an edge (466) of a tooth (462) of the first component (42) of the slider dog (40) include respective parallel inclined surfaces (368, 468) oriented, with respect to the rotation axis (A30), in opposite directions and wherein the inclined surfaces (368, 468) can slide one against the other.

12. The parking brake system of one of the preceding claims, wherein an angular amplitude (y) of a rotational movement of the first component (42) of the slider dog (40), around the rotation axis (A30), with respect to the second component (44) of the slider dog is at least as large as an angular pitch (a) of the teeth (362) of the dog clutch part (30).

13. The parking brake system of claim 12, wherein the angular amplitude (y) is between 5° and 30°, preferably between 10° and 20°.

14. The parking brake system of one of the preceding claims, wherein a lead screw assembly (34, 66) slides the slider dog (40) along the direction (A50) parallel to the rotation axis (A30).

15. The parking brake system of one of the preceding claims, wherein a bi-stable solenoid (68) slides the slider dog along the direction (A50) parallel to the rotation axis (A30).

16. The parking brake system of one of the preceding claims, wherein a bi-stable magnetic clutch (68) slides the slider dog along the direction (A50) parallel to the rotation axis (A30).

17. A vehicle (2) including a chassis (4), at least one wheel (6) rotatable with respect to the chassis and a parking brake system according (16) to one of the preceding claims.

18. The vehicle of claim 17, wherein the dog clutch (30) is fixed in rotation, around the rotation axis (A30), with the wheel (6), wherein the rotation axis (A30) is superimposed with a rotation axis (A6) of the wheel and the park lock device (20) is configured to selectively lock one wheel (6A, 6B).

19. The vehicle of claim 18, wherein the dog clutch part (20) is integral with a central shaft (34) of the wheel (6) and / or with a service brake disc (32).

20. The vehicle of claim 17, wherein the dog clutch is fixed in rotation with an entry shaft (10) of a differential (12) of the vehicle (2), wherein the rotation axis (A30) is superimposed with a rotation axis (A10) of the entry shaft and the park lock device is configured to selectively lock at least two wheels (6B) driven by the differential (12).

Images