Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/352—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using bevel or epicyclic gear
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/352—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using bevel or epicyclic gear
  • F01L2001/3521—Harmonic drive of flexspline type

Definitions

• the present invention relates to the field of setting the laws of valve lift, specific to the internal combustion engine. It relates more particularly to a camshaft incorporating a phase shift device for a variable distribution motor.
• the timing of the intake and exhaust valve lift laws is usually a compromise between different objectives. For example, a search for maximum performance will involve a compromise between low-end torque and maximum high-end power. On the other hand, a compromise between idle stability, emission of low-load pollutants and high-end power can be considered.
• the invention relates more particularly to the field of electrical devices for adjusting the angle of rotation of a camshaft.
• the present invention relates, in its most general sense, to an adjustment device for the continuous phase shift of the rotation angle of a camshaft controlling the gas exchange valves.
• an internal combustion engine with respect to a driving element, in particular a chain or belt comprising an electric brushless adjusting motor with a fixed stator relative to an outer ring, the motor being coupled to a three-input gearbox / Outputs comprising the outer ring, an input member and an output disk, the outer ring is driven by said drive member, said output disk being integral with the camshaft.
• the device comprises a single internal shaft to the stator of the electric motor, said electric motor comprising a rotor integral with the single shaft such that said single shaft supports the rotor of the electric motor and the input element of the gearbox.
• said reducer is a trochoidal type reducer
• the single axial shaft supports the eccentric or eccentric allowing a trochoidal type reduction.
• said outer ring has on its inner surface a tubular toothed path meshing with one or more toothed wheels mounted on said eccentrics having holes of circular section distributed over the annular zone of said toothed wheel, the trochoidal reducer comprising a set of pins having a section smaller than that of said bores, said pins being secured to said output disk, and passing through said bores to ensure the transmission of movement between said eccentric gear wheel and said output disk.
• said reducer is an epicyclic reduction gear
• the single axial shaft carries the inner sun gear
• said outer ring has on its inner surface a tubular toothed path meshed with one or more satellites, the satellites being movable in rotation around pins integral with said output disk to ensure the transmission of movement between the satellites and said output disk.
• said single shaft has a through bore.
• said output disc is secured to the camshaft by a screw having a complementary thread of the internal thread of the camshaft, and bearing against a radial shoulder of said output disc.
• said electric motor is included in an outer casing having a housing receiving a guide element of said single shaft.
• the stator of said electric motor is overmolded and secured to said outer casing.
• said electric motor advantageously comprises a printed circuit supporting the electronic control and supply components of the electric coils carried by the stator.
• the latter advantageously comprises at least one position sensor delivering a signal that is a function of the angular position of said output disk.
• the device also preferably comprises at least one position sensor delivering a signal that is a function of the angular position of said outer ring.
• said electric motor may have an outer outer surface envelope complementary to a housing provided on the engine cylinder head.
• said outer casing may also have fixing elements for attachment to the cylinder head of the combustion engine.
• FIGS. 1a and 1b show a longitudinal sectional view of a device according to the following invention a first embodiment and using respectively a trochoidal type reducer and an epicyclic type reducer,
• FIG. 2 represents an isolated view of an exemplary gear wheel belonging to the trochoidal gearbox possible for the invention
• FIG. 3 represents an isolated view of an example of an output assembly of a trochoidal type gearbox possible for the invention
• FIG. 4 represents an exploded view of an exemplary embodiment of a trochoidal type gearbox possible for the invention
• FIG. 5 represents an exploded view of an exemplary embodiment of the invention by subassembly
• FIG. 6 represents a longitudinal sectional view of a device according to the invention according to a second embodiment
• FIG. 7 represents an exploded view of the second embodiment of the invention by subassembly
• FIG. 8 represents an isolated view of an embodiment of an output assembly highlighting the interest of the pin-holder used for measuring the phase shift
• FIG. 9 represents a view of an adjusting device according to the invention, mounted on the cylinder head of an internal combustion engine,
• FIG. 10 represents a view in longitudinal section of a device according to the invention according to a third embodiment
• Figure 11 shows a longitudinal sectional view of a device according to the invention according to a fourth embodiment.
• Figure la shows a sectional view of a device according to an embodiment of the invention, coupled to a camshaft (1).
• the device consists of an electric motor (2) associated with a gearbox (3), here trochoidal type.
• the gearbox (3) comprises an outer ring (4) driven by the chain or timing belt of the internal combustion engine (not shown).
• This outer ring (4) has a typical outer diameter of 100 to 150 millimeters and has outer teeth adapted to the drive by said distribution chain.
• This outer ring (4) is free to rotate relative to the camshaft (1).
• An eccentric toothed wheel (6) has a lower section than the inner section of the outer ring (4), the number of teeth of the toothed wheel (6) being smaller than the number of teeth of the toothed track (5) on the inner surface the outer ring (4), identical module.
• the difference between the number of teeth of the toothed wheel (6) and the number of teeth of the toothed path (5) on the inner surface of the outer ring (4) is advantageously one tooth in order to maximize the reduction ratio of the trochoidal reducer (3).
• This toothed wheel (6) is guided by a bearing (7) mounted on the single shaft (8) at an eccentric (9) whose axis of revolution is eccentric with respect to the central axis of the single tree (8).
• the offset between these two axes is generally between 0.1 and 1 mm and depends on the modulus of the toothing of the trochoidal meshing.
• the eccentric toothed wheel (6) has a series of circular bores (10) distributed angularly on an annular track, as is appreciated in FIG. As seen in Figure 3, these holes (10) are traversed by pins (11) of circular section S g less than the section S p circular holes (10).
• the circular section S g has a diameter less than twice the eccentricity between the single shaft (8) and the eccentric (9) with respect to the diameter of the section S p .
• This pins (11) are perpendicular to the transverse surface of an output disk (12).
• This output disk (12) is coaxial with the single shaft (8) and is free to rotate with respect to this single shaft (8). It is guided, relative to this single shaft (8) by a bearing (13).
• the pins (11) are taken up at their end by a pin holder (20) advantageously to increase the torsional stiffness of the output assembly (21) of the reducer
• Said pin holder (20) can, in a particular embodiment, be advantageously guided on a cylindrical inner surface (27) of the outer ring
• the output disk (12) has a shoulder (14) for guiding the outer ring (4).
• This output disk (12) is also secured to the camshaft (1) by a screw (23) with which it is coupled via a radial expansion (15), close to the axis of rotation of the formed assembly.
• the invention is not limited to the trochoidal type reducer. Indeed, other reducers can be used, for example an epicyclic type reducer.
• Figure lb we see, as for the case of Figure la, a sectional view using such a reducer.
• the choice of a gearbox or other can be dictated according to the desired reduction ratio and depending on the final cost of the solution.
• the single shaft (8) carries a sun gear (34) which meshes with satellites (35), typically two or three in number, which also mesh with the toothed path.
• satellites (35) typically two or three in number, which also mesh with the toothed path.
• outer ring (4) outer ring (4).
• These satellites (35) are rotatable about pins (11) integrally connected to the output disk (12), the latter forming the carrier.
• the relative displacement regulated between the sun gear (34) and the outer ring (4) thus makes it possible to adjust the phase shift.
• the motor (2) comprises a rotor (16) integral with the single shaft (8). It has permanent magnets (17) alternately magnetized, typically radially or festooned.
• the single shaft (8) carries the input element of the gear reducer: for example the eccentric gear (6) in the case of the trochoidal gearbox, or the inner sun gear (34) in the gearbox. case of epicyclic reducer.
• the stator (18) of the electric motor (2) is constituted by a set of electric coils (24), forming a polyphase assembly, and a ferromagnetic part, generally laminated.
• the motor (2) further comprises an electronic control circuit (19) controlling the operation of the motor, with synchronous rotation with the timing chain, except during the phase shift control.
• the assembly formed by the stator (18), the rotor (16) and the electronic circuit (19) is positioned in an outer casing (29), which can be a casing or a skin overmoulding.
• the single shaft (8) can thus be guided relative to the outer casing (29) through a bearing (30) between the reduction assembly and the rotor (16).
• a seal (22), typically a lip seal, is positioned on the single shaft (8) in contact with the outer casing (29) of the motor.
• the assembly of the formed geared motor assembly is greatly simplified. Indeed, the assembly of the rotor (16) and the output disk (21), as well as all the elements of the gear (3) can be realized on the single shaft (8) and the electric motor (2) can be mounted on this single shaft (8), after positioning the seal (22) to allow assembly of the assembly on the cam shaft (1) via the radial expansion (15) which has a smaller diameter to the hollow inner diameter of the single shaft (8). By screwing this radial expansion (15) on the camshaft (1), the single shaft (8) can thus be fixed coaxially with the camshaft (1).
• An important advantage of the solution is therefore to be able to present a single shaft (8) completely hollow, allowing the easy screwing of the gear (3) after positioning the assembly.
• FIG. 5 allows to appreciate the subassemblies described and their order of assembly.
• the single input shaft (8) of the gearbox, carrying the magnet of the electric motor (2) is completely guided and carried by the gearbox ( 3).
• This embodiment makes it possible, in a first step, to place the gearbox (3) with the single shaft (8) carrying the rotor (16) directly on the camshaft (1), then in a second step to insert directly the stator (18) of the electric motor (2) on said input shaft (8).
• the assembly is facilitated and can be greatly simplified.
• the mechanical clearance between the magnet (17) of the electric motor (2) and the stator (18) must advantageously be increased in order to tolerate the probable misalignments between the single input shaft (8).
• Figure 7 shows the ease of assembly by first placing the gearbox (3) with the single shaft (8) on the camshaft (1), then the stator (18) of the electric motor (2). which is otherwise screwed onto the cylinder head of the engine (26) at a housing (25) by means of fasteners (33) here in the form of eyelets, to form an assembly as shown in FIG. 9 .
• the use of the gearbox (3) advantageously allows to integrate a position sensor.
• the pin holder (20), sliding on the cylindrical inner surface (27) of the outer ring (4) is connected to the output disc (12) to form the output assembly (21). .
• a sensor magnet integral with this output assembly for example in the form of a disk or a magnet ring (31).
• the positioning of a magnetic field measurement probe placed on the stator (18) side, facing the magnetic ring or disk (31) thus makes it possible to constitute an absolute phase shift position sensor, that is to say say allows the knowledge of the position of the camshaft (1).
• knowledge of the phase shift is thus possible.
• variable reluctance motor can also be considered in place of the magnet rotor motor.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=57136978

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (2)

Citations (3)

Family Cites Families (10)

• 2016
  • 2016-05-27 FR FR1654778A patent/FR3051835B1/fr not_active Expired - Fee Related
• 2017
  • 2017-05-24 EP EP17726279.7A patent/EP3464841A1/de not_active Withdrawn
  • 2017-05-24 US US16/302,945 patent/US20190301313A1/en not_active Abandoned
  • 2017-05-24 JP JP2018560766A patent/JP2019517635A/ja active Pending
  • 2017-05-24 WO PCT/EP2017/062636 patent/WO2017202971A1/fr not_active Ceased

Patent Citations (3)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events