Motor unit and a wheeled vehicle and a machine tool equipped with such a motor unit

Abstract

The invention relates to a motor unit (1) comprising an electric motor (2) and a support (3), said motor (2) comprising a tool-holder shaft (4) with a rotor (7) for rotating said shaft (4), a stator (8) and a frame (9), said motor unit (1) having selectively activatable first and second configurations and an activation device (10) for the passage from one configuration to another, the motor (2) and the support (3) being, independently of a rotational movement of the rotor (7), mounted so as to be fixed axially in the first configuration, the tool-holder shaft (4), at its end (6) opposite its tool-holder end (5), partially projecting from the frame (9) and having, at its projecting portion, a screw thread (11). The tool-holder shaft (4) is mounted so as to be fixed axially with respect to the rotor (7) and to the stator (8). In the second configuration, the motor (2) and the support (3) are, depending on the rotational movement of the rotor (7), mounted so as to be movable axially relative to one another in a direction parallel to the shaft (4) in order to vary the position of the tool-holder end (5) of the shaft (4) relative to the support (3), each axial relative position between the tool-holder end (5) of the shaft (4) and the support (3) being a stable position.

Description

Description Title of the invention: MOTOR GROUP AS WELL AS A ROLLING MACHINE AND A MACHINE TOOL EQUIPPED WITH SUCH A MOTOR GROUP

[0001] The present invention relates to a power unit, as well as a rolling machine and a machine tool equipped with such a power unit.

[0002] It relates in particular to a motor group comprising an electric motor and a support, said motor comprising a so-called tool-holder shaft with a tool-holder end, a rotor for driving said shaft in rotation, a stator, and a casing surrounding the stator and the rotor, said motor group having a first and a second selectively activatable configuration, and an activation device for switching from one configuration to another, the motor and the support being, independently of a rotational movement of the rotor, mounted, in the first configuration, axially fixed in a direction parallel to the shaft.

[0003] A device for driving a tool-holder motor shaft in rotation having two configurations and allowing said shaft to be axially fixed relative to a support in a first configuration is known as illustrated in document WO 2022 / 069841. In the second configuration, the shaft and the stator are mounted to be axially movable relative to each other depending on the rotational movement of the rotor. Such a device has the advantage of being able to generate an axial displacement of the shaft under the effect of a rotational drive of the rotor in the second configuration, this rotor also making it possible to conventionally drive the shaft in rotation without axial displacement in the first configuration. This results in simplicity compared to devices which require two motors, one for driving the shaft in rotation, the other for driving the shaft in axial displacement.However, the solution as described in patent application WO 2022 / 069841 is not perfect in terms of mechanical strength. In particular, depending on the design chosen, the tool holder shaft may have a significant overhang relative to the rolling members that carry it. In addition, this shaft sometimes has to be made. in several pieces, which leads to inaccuracy in the settings and again to a risk of breakage.

[0004] An aim of the invention is to propose a motor unit whose design makes it possible to overcome the drawbacks of the state of the art.

[0005] For this purpose, the invention relates to a motor group comprising an electric motor and a support, said motor comprising a so-called tool-holder shaft with a tool-holder end, a rotor for driving said shaft in rotation, a stator, and a casing surrounding the stator and the rotor, said motor group having a first and a second selectively activatable configuration, and an activation device for switching from one configuration to another, the motor and the support being, independently of a rotational movement of the rotor, mounted, in the first configuration, axially fixed in a direction parallel to the shaft, characterized in that the tool-holder shaft is mounted axially fixed relative to the rotor and the stator, in that the tool-holder shaft, at its end opposite its tool-holder end, partially projects from the casing, and has, at its projecting portion, a thread, in that in the second configuration,the motor and the support are, depending on the rotational movement of the rotor, mounted axially movable relative to each other in a direction parallel to the shaft to vary the position of the tool-holder end of the shaft relative to the support, each axial relative position between the tool-holder end of the shaft and the support being a stable position. It should be noted that a stable position within the meaning of the invention means a position that can be maintained after stopping the motor in the state in which the motor unit is not supplied with electricity. Conversely, an unstable position is a position that cannot be maintained in the state in which the motor unit is not supplied with electricity. In the second configuration, the rotational drive of the rotor allows a relative axial displacement of the motor and the support, the direction of the relative axial displacement being a function of the direction of rotation of the rotor. Thus,the rotation of the rotor in a first direction of rotation causes a relative axial displacement of the motor and the support in a first direction while the rotation of the rotor in a second direction of rotation causes a relative axial displacement of the motor and the support in a second direction opposite to said first direction. In the first configuration, conversely, the motor and the support are, independently of a rotational movement of the rotor, i.e. in the driven state of the rotor and in the non-driven state of the rotor, arranged axially fixed relative to each other. Thus, the rotor is a multi-purpose rotor which, in addition to its role of driving the shaft in rotation, can control a relative axial displacement of the motor and consequently of the shaft relative to the support. The direction of rotation, the operating time and the angular range of displacement of the rotor therefore control the relative axial displacement of the motor and the support in the second configuration. The above results in a simplicity of the motor unit since the rotor forms the control motor element in all configurations without having to have an additional motor element.It is thus possible, for example, in the case of an application of such a motor unit to a mowing machine, to control the adjustment of the cutting height and the rotational drive of the cutting blade from a single rotor without harming the mechanical strength of the motor unit. Indeed, the tool-carrying shaft remains, regardless of the configuration of the motor unit, axially fixed relative to the rotor. Thus, in the second configuration, the motor and the support are, depending on the rotational movement of the rotor, mounted axially movable to vary the position of the tool-carrying end of the shaft relative to the support in the direction of moving towards or away from the support without varying the position of this tool-carrying end of the shaft relative to the rotor or the stator.

[0006] According to one embodiment of the invention, the activation device comprises at least one first threaded part housed at least partially inside the support with the threading of this first part permanently engaged with the thread of the shaft. This design allows, in the driven state in rotation of the shaft and in the immobilized state in rotation of the first part, by cooperation of the thread of the shaft with the threading of the first part immobilized in rotation, an axial displacement of the shaft.

[0007] According to one embodiment of the invention, the activation device comprises at least one second part integral in rotation with the shaft and mounted axially movable on the shaft between a position separated from and a position close to the first part in which the rotational movement of the second part is capable of being transmitted to the first part by contact of said first and second parts between them and a two-position actuator, one corresponding, called the first position, to the first configuration, the other, called the second position, to the second configuration of the motor group, said actuator being in its second position corresponding to the second configuration active on both the first and second parts to ensure in parallel the immobilization in rotation of the first part and the maintenance of the second part in a position separated from the first part. The first position of the actuator, corresponding to the first configuration of the motor group, is a position in which the second part is in a position close to the first part to transmit its rotational movement to the first part, and the first part is free to rotate with the shaft which carries it.

[0008] According to one embodiment of the invention, the motor group comprises an actuator relay interposed between the actuator and the second part, and the actuator is, in its second position corresponding to the second configuration, active on the second part via said relay in the form of a pivoting lever.

[0009] According to one embodiment of the invention, the second part is equipped with a return member in a position close to the first part and the actuator is equipped with an element for returning the actuator to the first position corresponding to the first configuration of the motor group in which the second part is in a position close to the first part to transmit its rotational movement to the first part and the first part is free to rotate with the shaft which carries it.

[0010] According to one embodiment of the invention, the first part is, in the state housed at least partially inside the support, arranged at least partially between the second part and a rolling member housed inside the support for a sandwiching of the first part between the second part and the rolling member in a position close to the second part of the first part so that any axial displacement of the first part is prevented. This arrangement makes it possible to prevent any axial displacement of the first part at least in the first configuration of the motor unit.

[0011] According to one embodiment of the invention, the first part and the second part are respectively provided with dog elements for dog coupling in the close position of the first and second parts. This dog coupling allows the transmission of the rotational movement of the second part integral in rotation with the tool holder shaft to the first part in a simple and safe manner.

[0012] According to one embodiment of the invention, the first part comprises, preferably made in a single piece, a nut, a skirt extending in the axial extension of the nut and radial arms arranged around the skirt / nut assembly.

[0013] According to one embodiment of the invention, the dog elements of the first part are arranged inside the skirt.

[0014] According to one embodiment of the invention, the second part is at least in the form of a cylindrical body provided at each of its ends with a centrally hollowed flange so that it can be threaded onto the shaft, the flange closest to the first part being provided with the dog elements of said second part.

[0015] According to one embodiment of the invention, the actuator is formed by the movable part of an electromagnetic system, such as a solenoid, the first and second positions of the actuator corresponding to one, to the position occupied by the movable part in the state not supplied with electricity of the electromagnetic system, the other, to the position occupied by the movable part in the state supplied with electricity of the electromagnetic system.

[0016] According to one embodiment of the invention, the support is a hollow body, the motor and the support are mounted in a sliding manner with a fitting area and, in the second configuration, the motor and the support are, depending on the rotational movement of the rotor, mounted, by sliding fitting, axially movable relative to each other, in a direction parallel to the shaft, in the sense of an increase or reduction of the fitting area, to vary the position of the tool-holder end of the shaft relative to the support.

[0017] According to one embodiment of the invention, the motor casing is equipped with guide members for sliding interlocking mounting with the support, said guide members made in one piece with the casing being in the form of rails capable of cooperating with slides provided in the support. Again, this construction results in simplicity of the motor unit without harming its mechanical strength.

[0018] According to one embodiment of the invention, the group comprises at least one end-of-travel sensor for the relative axial movement of the motor and the support with a part fixedly mounted on the motor and a part secured to the support, said parts interfering with each other in the extreme position of approach of the tool-holder end of the support shaft.

[0019] According to one embodiment of the invention, the tool-holder shaft surrounded by the rotor and the stator is equipped with at least one rolling member for holding the shaft inside the motor housing and the distance between the rolling member(s) and the tool-holder end of the tool-holder shaft is kept constant regardless of the configuration of the motor group. The distance between the rolling member(s) and the tool-holder end of the tool-holder shaft is therefore kept constant in the first and second configurations of the motor group.

[0020] According to one embodiment of the invention, the tool capable of being carried by the tool holder shaft is a cutting blade.

[0021] The invention also relates to a rolling machine, preferably for mowing, comprising a motor unit, characterized in that the motor unit is of the aforementioned type.

[0022] The invention also relates to a machine tool comprising a motor group, characterized in that the motor group is of the aforementioned type. Brief description of the drawings

[0023] The invention will be clearly understood upon reading the following description of exemplary embodiments, with reference to the appended drawings in which:

[0024] [Fig. 1] represents a perspective view of a rolling machine, in particular a mowing robot, equipped with a motor unit according to the invention;

[0025] [Fig. 2] represents in the form of two sectional views of the motor group and two partial perspective views each associated with a sectional view, the passage of the actuator of the activation device from a first position corresponding to the first configuration of the motor group to a second position corresponding to the second configuration of the motor group;

[0026] [Fig. 3] represents in the form of two sectional views of the motor group and two detailed views each associated with a sectional view, the axial movement of the motor relative to the support for the passage from a position spaced from the tool-holder end of the shaft relative to the support to a position close to the tool-holder end of the shaft relative to the support;

[0027] [Fig. 4] represents a partial perspective view, in exploded position of the elements, of the tool holder shaft and the associated activation device;

[0028] [Fig. 5] shows in the form of two front views, the motor group during the passage from a position spaced from the tool-carrying end of the shaft relative to the support to a position close to the tool-carrying end of the shaft relative to the support;

[0029] [Fig. 6] represents a perspective view of the support and the carcass ready to be assembled by a sliding interlocking assembly;

[0030] [Fig. 7] represents a perspective view of the support and the carcass in the assembled state with sliding interlocking;

[0031] [Fig. 8] represents a perspective view of the first room taken from inside said first room;

[0032] [Fig. 9] represents a perspective view of a machine tool equipped with a motor unit according to the invention.

[0033] As mentioned above, the invention relates to a motor group 1 intended to be installed, for example, on a rolling machine 30, as illustrated in FIG. 1 which represents a mowing robot or on a machine tool 31, as illustrated in FIG. 9.

[0034] Such a motor group 1 comprises an electric motor 2 and a support 3. The motor 2 comprises a shaft 4 called the tool-holder shaft 4. This shaft 4 is intended to be equipped at one end, called the tool-holder end 5, with a tool of work. This work tool may be a cutting tool or a drilling tool or other. Figures 1 and 9 illustrate a work tool in the form of a rotating cutting blade.

[0035] The electric motor 2 further comprises a stator 8 and a rotor 7 for driving the shaft 4 in rotation in two directions of rotation. The rotor 7 is hollowed out centrally to delimit a through passage of the shaft 4 which forms the motor shaft of the electric motor 2. The rotor 7 is generally formed by a stack of laminations and by magnets arranged close to the periphery of the rotor in order to be attracted by a rotating magnetic field generated at the stator 8. The stator 8 is itself formed of laminations interacting with a winding to form an electromagnetic part. A carcass 9 at least partially envelops the electromagnetic part of the stator 8 and the rotor 7 in a manner known per se. The enclosure of this carcass 9 has at least one through opening from which the shaft 4 projects.This carcass 9, which envelops the rotor 7, the stator 8 and at least part of the shaft 4, can also delimit one or more cavities housing components, such as rolling members represented at 26 in figure 2. The or each rolling member 26 surrounds the shaft 4 and ensures that the shaft 4 is held inside the carcass 9.

[0036] The rotor 7 is a two-way rotor capable of rotating clockwise and counterclockwise. The electric motor 2, comprising the stator 4 and the rotor 7, may be a direct current or alternating current motor. This motor may be of the Brushless type. The support 3, more particularly visible in FIG. 6, is a hollow body intended to be fixed in a stationary manner to the rolling machine 30 or to the machine tool 31 which it equips. Generally, this support 3 is made of synthetic material. Here, it has the general shape of a bell provided with an external circumferential collar and a central recess inside which the end 6 of the shaft opposite the tool-holder end 5 of the shaft 4 can be housed. The collar assists in securing the bracket 3. The motor 2 and the bracket 3 are mounted in a sliding interlocking manner with an interlocking area 22 which corresponds to the area at which the motor 2 and the bracket 3 overlap.

[0037] For this sliding interlocking assembly, the casing 9 of the motor 2, which is a synthetic material part, is equipped with guide members 23. These guide members 23, made in one piece with the carcass 9, are in the form of rails capable of cooperating with slides 24 provided in the support 3.

[0038] In the example shown in Figure 6, the carcass 9 is in the form of a sleeve provided externally with a collar from which extend a plurality of fingers arranged parallel to the longitudinal axis of the sleeve. These fingers each form a rail constituting a member 23 for guiding the carcass 9. The assembly is carried out by simply inserting the members 23 for guiding the carcass 9 into the slides 24 of the support 3, as illustrated in Figure 7. These slides 24 have the form of longitudinal grooves formed in the body constituting the support 3.

[0039] It is noted that the part of the shaft 4, which extends at least partially inside the support 3, is a threaded part over at least part of the length of the shaft 4. This thread is shown at 11 in Figure 2. This thread is therefore arranged on the portion of the shaft 4 which projects from the carcass 9 in the direction of the support 3 in the mounted state with sliding interlocking of the support 3 and the motor 2. This portion of the shaft 4 which projects from the carcass 9 has as its driving end the end of the shaft 4 opposite the tool-holder end 5 of the shaft 4. In other words, the thread 11 is arranged on at least a portion of the part of the shaft 4 which projects from the carcass 9 and extends between the end of the shaft 4 opposite the tool-holder end 5 of the shaft 4 and the carcass 9.

[0040] As illustrated in the figures, the tool-carrying shaft 4 is mounted axially fixed, that is to say in a direction parallel to the longitudinal axis of the shaft 4 relative to the rotor 7 and the stator 8. As a result, the distance between the rolling member(s) 26 and the tool-carrying end 5 of the tool-carrying shaft 4 is kept constant regardless of the configuration of the motor group 1. This arrangement makes it possible to have appropriate mechanical strength of the shaft 4 at its tool-carrying end 5.

[0041] The motor group 1 has a first configuration and a second configuration. These first and second configurations are selectively activatable and the motor group 1 comprises an activation device 10 for switching from one configuration to another.

[0042] In the first configuration according to the left-hand views of Figure 2, the motor 2 and the support 3 are mounted axially fixed, one relative to the other, in a direction parallel to the shaft 4, in particular to its longitudinal axis, independently of a rotational movement of the rotor 7. In other words, whether the rotor 7 and consequently the shaft 4 rotate or not and whatever their direction of rotation, the motor 2 and the support 3 remain axially fixed relative to each other in this first configuration.

[0043] Conversely, in the second configuration, as illustrated in the right-hand views of Figure 2 or the views of Figure 3, the motor 2 and the support 3 are, depending on the rotational movement of the rotor 7, mounted axially movable relative to each other in a direction parallel to the shaft 4 to vary the position of the tool-holder end 5 of the shaft 4 relative to the support 3. Each axial relative position between the tool-holder end 5 of the shaft 4 and the support 3 is a stable position. Thus, in this second configuration, the motor 2 and the support 3 are, depending on the rotational movement of the rotor 7, mounted by sliding interlocking axially movable relative to each other in a direction parallel to the shaft 4 in the sense of an increase or reduction of the interlocking zone 22 to vary the position of the tool-holder end 5 of the shaft 4 relative to the support 3.This variation in the axial relative position between the tool-holder end 5 of the shaft 4 and the support 3 makes it possible to vary, in the case of an application conforming to the mowing robot of figure 1, the cutting height or, in the case of the machine tool of figure 9, the position of the cut.

[0044] To allow the transition from one configuration to another, the motor group 1 comprises an activation device 10, more particularly visible in figures 2 to 4. This activation device 10 comprises at least a first threaded part 12 housed at least partially inside the support 3 with the thread 121 of this first part 12 permanently engaged with the thread 11 of the shaft. 4.

[0045] This activation device 10 comprises a second part 13 integral in rotation with the shaft 4 and mounted axially movable on the shaft 4 between a position separated from and a position close to the first part 12 in which the rotational movement of the second part 13 is capable of being transmitted to the first part 12 by contact of said first and second parts 12 and 13 with each other.

[0046] The activation device 10 also comprises an actuator 14 with two positions, one of which, called the first position, corresponds to the first configuration of the motor group 1, the other, called the second position, to the second configuration of the motor group 1. This actuator 14 is, in its second position corresponding to the second configuration, active, both on the first and second parts 12 and 13, to ensure in parallel, the immobilization in rotation of the first part 12 and the maintenance of the second part 13 in a position separated from the first part 12.

[0047] The actuator is formed by the moving part of an electromagnetic system 21. This electromagnetic system 21 is here a solenoid with a winding around a core made of ferromagnetic material. This core, which constitutes the moving part of the electromagnetic system 21, is here in the form of a rod loaded by a spring which forms a return element 17 of the actuator 14. The core, which forms the actuator 14, is mounted to slide inside the coil when the coil is supplied with electric current against the action of the return element 17. The actuator 14 is therefore able to occupy two distinct positions depending on whether the electromagnetic system 21 is supplied with electricity or not.

[0048] The first position of the actuator 14, occupied by the actuator 14 in the state not supplied with electricity by the electromagnetic system 21, is shown in the left views of FIG. 2 and corresponds to the first configuration of the motor group.

[0049] The second position of the actuator 14, occupied by the actuator 14 in the electrically powered state of the electromagnetic system 21 is shown in the right-hand views of figure 2 or in figure 3 and corresponds to the second configuration of the motor group 1.

[0050] The return element 17, which returns the actuator 14 to the first position, is a helical spring surrounding the actuator 14 and arranged between a shoulder of the actuator 14 and the coil of the electromagnetic system 21.

[0051] In the first configuration of the motor group, corresponding to the situation in which the actuator 14 is in the first position, the second part 13 is in a position close to the first part 12 to transmit its rotational movement to the first part 12 and the first part 12 is free to rotate with the shaft 4 which carries it, as illustrated in the left views of figure 2.

[0052] To enable this transmission of the rotational movement of the second part 13 which is integral in rotation with the shaft 4 to the first part 12, the first part 12 and the second part 13 are respectively provided with dog elements for coupling by dog ​​engagement in the close position of the first and second parts. The dog elements of the first part 12 are shown at 19 in the figures, while the dog elements of the second part 13 are shown at 20 in the figures.

[0053] A detail of the first part 12 is shown in Figure 8. In this example, the first part 12 comprises, made in a single piece, a nut 122, a skirt 123 extending in the axial extension of the nut 122 and radial arms 124 arranged around the skirt 123 / nut 122 assembly. These dog elements 19 of the first part 12 are arranged inside the skirt 123.

[0054] These dog clutch elements 19 are formed by an internal peripheral crenellation of the skirt. The first part 12 is, in the state housed at least partially inside the support 3, arranged at least partially between the second part 13 and a rolling member 18 housed inside the support 3 for a sandwiching of the first part 12 between the second part 13 and the rolling member 18 in the position close to the second part 13 of the first part 12 so that any axial displacement of the first part 12 is prevented in the position close to the second part of the first part 12.

[0055] The second part 13 is equipped with a return member 16 in a position close to the first part 12. This return member 16 is in the form of an elastically deformable member, such as a spring, interposed between the first and second parts. This return member 16 is, in the example of figures 2 and 3, housed inside the skirt of the first part between the edge free from the skirt and a shoulder of the second part 13 inserted at least partially into the skirt 123.

[0056] The second part 13 is at least in the form of a cylindrical body 131 provided at each of its ends with a flange 132 hollowed out centrally so that it can be threaded onto the shaft 4. The flange 132 of the second part 13 closest to the first part 12 is provided with the dog elements 20 of the second part 13. These dog elements 20 are particularly visible in Figure 4. These dog elements are formed by a crenellation provided on the external face of the flange 132 intended to be inserted inside the skirt 123 of the first part 12. Thus, the crenellations of the crenellation of the second part 13 come, in a position close to the first and second parts, to be inserted into the space left free between two crenellations of the crenellation of the first part 12 so that in the state driven in rotation of the second part 13, the first piece 12 rotates with the second piece 13.

[0057] The second part 13 is, for its mounting integral in rotation with the shaft 4 and axially free on the shaft 4, connected to the shaft 4 by a pin. This pin, visible in Figure 4, passes through the shaft 4 and is inserted into two longitudinal slots or openings of the second part 13. During its passage from the first to the second position, under the effect of an electrical supply from the electromagnetic system, the actuator 14 is configured to act on a relay 15 of the actuator 14. This relay 15 is here in the form of a pivoting lever visible in Figure 4. This pivoting lever itself acts during its pivoting on the second part 13 against the action of the member 16 for returning the second part 13 to the position close to the first part 12. This pivoting lever thus allows the passage of the second part 13 from the close position to the position separated from the first part 12 by pressing on one of the flanges 132 of the second part 13.

[0058] In parallel with its action on the relay 15, the actuator 14 is also configured to, during its passage from the first to the second position, act on the first part 12 to immobilize the first part 12 in rotation. For this purpose, the end of the rod constituting the actuator 14 is configured to, in the second position of the actuator 14, come to be positioned between the arms 124 radials of the first part 12, so that the first part 12 can no longer rotate, as illustrated in the right views of Figure 2.

[0059] The actuator 14 is therefore in its second position, corresponding to the second configuration of the motor group 1, active both on the first part 12 which it immobilizes in rotation and on the second part 13 by means of the relay 15 for maintaining the second part 13 in a position separated from the first part 12 so that the dog clutch elements 19 and 20 are in the disengaged state and the second part 13 no longer transmits its rotational movement to the first part 12.

[0060] It is understood that, in this second configuration, the rotational drive of the shaft 4 causes, by cooperation of the thread 11 of the shaft 4 with the tapping 121 of the first part 12 immobilized in rotation, an axial displacement of the shaft 4 and, consequently, of the rotor 7 and the stator 8 of the motor with which the shaft 4 is mounted axially fixed.

[0061] The axial displacement of the shaft 4 takes place in a direction depending on the direction of rotation of the shaft 4 so that the socket area 22 can vary in the direction of an increase, as illustrated in Figure 3, when moving from the left-hand views to the right-hand views of Figure 3, or in the direction of a reduction of the socket area 22 when the direction of rotation of the shaft 4 is reversed.

[0062] Finally, to complete the motor group 1, said motor group 1 comprises at least one end-of-travel sensor 25 for the relative axial displacement of the motor 2 and the support 3 with a part 251 fixedly mounted on the motor 2 and a part 252 secured to the support 3. The parts 251 and 252 interfere with each other in the extreme position of approach of the tool-holder end 5 of the shaft 4 of the support 3.

[0063] In the example shown in Figure 3, the part 251 fixedly mounted on the motor has the shape of a U with emission of a ray, for example a light ray, extending between the branches of the U. The part 252, mounted integrally with the support 3, is formed by a rod which intersects the radius of the part 251 mounted on the motor 2 in the position in which the support and the motor have the largest interlocking zone 22, as illustrated in the right-hand view of Figure 3. This cutting of the beam makes it possible to detect an end-of-stroke position for nesting the motor 2 inside the support 3. A signal can be sent to the control unit of the motor group 1. This control unit is in the form of an electronic and computer system which comprises, for example, a microprocessor and a working memory. According to a particular aspect, the control unit can be in the form of a programmable controller.

[0064] In other words, the described functions and steps can be implemented in the form of a computer program or via hardware components (e.g., programmable gate arrays). In particular, the functions and steps performed by the control unit or its modules can be implemented by computer instruction sets or modules implemented in a processor or controller or can be implemented by dedicated electronic components or FPGA or ASIC type components. It is also possible to combine computer parts and electronic parts.

[0065] Where it is specified that the unit or means or modules of said unit are configured to carry out a given operation, this means that the unit comprises computer instructions and the corresponding execution means which enable said operation to be carried out and / or that the unit comprises corresponding electronic components

[0066] This control unit can control the angular position of the rotor, the duration of rotation of the rotor, the rotational speed and the direction of rotation of the rotor. These elements influence in the second configuration the axial relative displacement path between the support 3 and the motor 2. The desired axial displacement path can be entered by the user in the control unit, for example via a human / machine interface or can be pre-stored. The value of the thread pitch of the shaft can also be stored to control the axial displacement.

[0067] In practice, the operation of the motor group 1, as described above, is as follows. It is assumed that the actuator 14 of the activation device 10 is in the first position corresponding to the state not supplied with electricity to the electromagnetic system 21, as illustrated in the left views of the Figure 2. The motor group 1 is therefore in the first configuration. In this first configuration, the motor 2 and the support 3 are mounted axially fixed relative to each other, including in the state in which the rotor 7 and, consequently, the shaft 4 are driven in rotation. The actuator 14 is returned by the return element 17 to a position separated from the first part 12 which is thus free to rotate with the shaft 4. The second part 13 is returned by the return member 16 to a position close to the first part 12 and the clutch elements 19 and 20 are in the clutched state, so that the rotational movement of the shaft 4 can be transmitted by the second part 13 to the first part 12. The first and second parts as well as the shaft 4 thus form a rotating assembly with the shaft 4 which drives the working tool in rotation when it is present.When the electromagnetic system 21 is powered with electricity, the actuator 14 is brought into the second position, corresponding to the second configuration of the motor group in which the motor 2 and the support 3 are mounted axially movable relative to each other in a direction parallel to the shaft 4, in particular to its longitudinal axis to vary the position of the tool-holder end 5 of the shaft 4 relative to the support 3.

[0068] In this second position of the actuator 14, the latter acts via the relay 15 on the second part 13 to keep it separated from the first part 12 and on the first part 12 to prevent it from being driven in rotation, as illustrated in the right-hand views of FIG. 2. In this second position of the actuator 14, the rotational movement of the second part 13 is no longer transmitted to the first part 12 by the dog clutch elements 19 and 20 and the first part 12 being prevented from rotating, a rotational movement of the shaft 4 generates, by cooperation of the thread 11 of the shaft 4 and the tapping 121 of the first part 12, a relative axial displacement of the shaft 4 / rotor 7 / stator 8 assembly and of the support 3 which results in a variation in the dimension of the socket zone 22, as illustrated in FIG. 3 and FIG. 5.It should be noted, as illustrated in Figure 5, that the support 3 and the motor 2 can be connected to each other by a protective bellows 28 which protects at least a portion of the part of the motor 2 extending projecting from the support 3. As soon as the electromagnetic system 21 is no longer powered, the actuator 14 of the activation device 10 returns to the first position under the effect of its return element 17. and relieves the second part 13 of any pressure so that this second part 13 returns to a position close to the first and second parts under the effect of its return member 16. The motor group 1 is in the first configuration in which the rotation of the shaft 4 has no effect on the relative axial position of the motor 2 and the support 3.

[0069] The operation of such a motor group 1 is therefore extremely simple and a single motor allows both the rotational drive of the shaft 4 and the associated working tool and a relative axial displacement of the support 3 and the motor 2 and, consequently, of the shaft 4 without harming the mechanical strength of the motor group 1 with respect to the overhang of the tool-carrying end 5 of the shaft 4 relative to the casing 9 and the bearing members 26 supporting the shaft 4 in the motor 2. The shaft 4 can be in one piece. The length of the shaft 4 taken between the two ends of the shaft 4 remains unchanged when changing from one configuration to another.

Claims

Claims

1. Motor group (1) comprising an electric motor (2) and a support (3), said motor (2) comprising a shaft (4) called a tool holder with a tool holder end (5), a rotor (7) for driving said shaft (4) in rotation, a stator (8), and a casing (9) surrounding the stator (8) and the rotor (7), said motor group (1) having a first and a second selectively activatable configuration and an activation device (10) for switching from one configuration to another, the motor (2) and the support (3) being, independently of a rotational movement of the rotor (7), mounted, in the first configuration, axially fixed in a direction parallel to the shaft (4), characterized in that the tool holder shaft (4) is mounted axially fixed relative to the rotor (7) and to the stator (8), in that the tool holder shaft (4), at its end (6) opposite its tool holder end (5), partially protruding from the carcass (9), and presents,at its projecting portion, a thread (11), in that in the second configuration, the motor (2) and the support (3) are, depending on the rotational movement of the rotor (7), mounted axially movable relative to each other in a direction parallel to the shaft (4) to vary the position of the tool-holder end (5) of the shaft (4) relative to the support (3), each axial relative position between the tool-holder end (5) of the shaft (4) and the support (3) being a stable position.,

2. Motor group (1) according to claim 1, characterized in that the activation device (10) comprises at least one first threaded part (12) housed at least partially inside the support (3) with the thread (121) of this first part (12) permanently engaged with the thread (11) of the shaft (4).

3. Engine group (1) according to claim 2, characterized in that the activation device (10) comprises at least one second part (13) integral in rotation with the shaft (4) and mounted axially movable on the shaft (4) between a position separated from and a position brought closer to the first part (12) in which the rotational movement of the second part (13) is capable of being transmitted to the first part (12) by contact of said first and second parts (12, 13) with each other and an actuator (14) with two positions, one corresponding, called the first position, to the first configuration, the other, called the second position, to the second configuration of the motor group (1), said actuator (14) being, in its second position corresponding to the second configuration, active on both the first and second parts (12, 13) to ensure in parallel the immobilization in rotation of the first part (12) and the maintenance of the second part (13) in a position separated from the first part (12).

4. Engine group (1) according to claim 3, characterized in that the engine group (1) comprises a relay (15) of the actuator (14) interposed between the actuator (14) and the second part (13), and in that the actuator (14) is, in its second position corresponding to the second configuration, active on the second part (13) by means of said relay. (15) in the form of a pivoting lever.

5. Engine group (1) according to one of claims 3 or 4, characterized in that the second part (13) is equipped with a member (16) for returning it to a position close to the first part (12) and in that the actuator (14) is equipped with an element (17) for returning the actuator (14) to the first position corresponding to the first configuration of the engine group (1) in which the second part (13) is in a position close to the first part (12) to transmit its rotational movement to the first part (12) and the first part (12) is free to rotate with the shaft (4) which carries it.

6. Engine group (1) according to one of claims 3 to 5, characterized in that the first part (12) is, in the state housed at least partially inside the support (3), arranged at least partially between the second part (13) and a rolling member (18) housed inside the support (3) for sandwiching the first part (12) between the second part (13) and the rolling member (18) in a position close to the second part (13) of the first part (12) so that any axial displacement of the first part (12) is prevented.

7. Engine group (1) according to one of claims 3 to 6, characterized in that the first part (12) and the second part (13) are respectively provided with dog clutch elements (19; 20) for dog clutch coupling in the close position of the first and second parts (12; 13).

8. Engine group (1) according to one of claims 2 to 7, characterized in that the first part (12) comprises, preferably made in a single piece, a nut (122), a skirt (123) extending in the axial extension of the nut (122) and radial arms (124) arranged around the skirt (123) / nut (122) assembly.

9. Engine group (1) according to claim 8 taken in combination with claim 7, characterized in that the dog clutch elements (19) of the first part (12) are arranged inside the skirt (123).

10. Engine group (1) according to claim 7 or one of claims 8 or 9 taken in combination with claim 7, characterized in that the second part (13) is at least in the form of a cylindrical body (131) provided at each of its ends with a flange (132) hollowed out centrally so that it can be threaded onto the shaft (4), the flange (132) closest to the first part (12) being provided with the dog elements (20) of said second part (13).

11. Motor group (1) according to one of claims 3 to 10, characterized in that the actuator (14) is formed by the movable part of an electromagnetic system (21), such as a solenoid, the first and second positions of the actuator (14) corresponding one to the position occupied by the movable part in the state not supplied with electricity of the electromagnetic system (21), the other to the position occupied by the movable part in the state supplied with electricity of the electromagnetic system (21).

12. Motor group (1) according to one of claims 1 to 11, characterized in that the support (3) is a hollow body, in that the motor (2) and the support (3) are mounted in a sliding manner with a fitting area (22) and in that, in the second configuration, the motor (2) and the support (3) are, depending on the rotational movement of the rotor (7), mounted, by sliding fitting, axially movable relative to each other, in a direction parallel to the shaft (4), in the sense of an increase or reduction of the fitting area (22), to vary the position of the tool-carrying end (5) of the shaft (4) relative to the support (3).

13. Motor group (1) according to one of claims 1 to 12, characterized in that the casing (9) of the motor (2) is equipped with guide members (23) for sliding interlocking mounting with the support (3), said guide members (23), made in one piece with the casing (9), being in the form of rails capable of cooperating with slides (24) formed in the support (3).

14. Motor group (1) according to one of claims 1 to 13, characterized in that it comprises at least one end-of-travel sensor (25) for the relative axial displacement of the motor (2) and the support (3) with a part (251) fixedly mounted on the motor (2) and a part (252) integral with the support (3), said parts (251, 252) interfering with each other in the extreme position of approach of the tool-holder end (5) of the shaft (4) of the support (3).

15. Motor group (1) according to one of claims 1 to 14, characterized in that the tool-carrying shaft (4) surrounded by the rotor (7) and the stator (8) is equipped with at least one rolling member (26) for holding the shaft (4) inside the casing (9) of the motor (2) and in that the distance between the rolling member(s) (26) and the tool-carrying end (5) of the tool-carrying shaft (4) is kept constant whatever the configuration of the motor group (1).

16. Motor group (1) according to one of claims 1 to 15, characterized in that the tool capable of being carried by the tool-carrying shaft (4) is a cutting blade (27).

17. Rolling machine (30), preferably for mowing, comprising a motor group (1), characterized in that the motor group (1) conforms to one of claims 1 to 16.

18. Machine tool (31) comprising a motor group (1), characterized in that the motor group (1) is in accordance with one of claims 1 to 16.

Images