[0001] This patent application relates to tubular motor reducer for the handling of winding
roller shutters or sunblinds comprising a mechanic device incorporated in the epicyclic
reduction gear used to prevent motion reversibility. The device allows the motor reducer
to drag the winding element into rotation in both directions and prevents it from
moving backwards and dragging the motor shaft into rotation.
[0002] The tubular motor reducer according to the present invention comprises a multi-step
epicyclic reduction gear housed in a fixed tubular element whose internal wall features
a crown gear on which the crown wheels of the various steps of the epicyclic reduction
gear engage. The epicyclic reduction gear is dragged into rotation by an electric
motor located outside the tubular element and positioned so that its shaft is coaxially
aligned with the tubular element, from whose front end the pin for the power takeoff
projects.
[0003] The adapter designed to drag the winding shaft of the roller shutter or sunblind
into rotation is splined on the pin.
[0004] Since the motion transmission from the electric motor to the power takeoff pin is
not irreversible, this type of tubular motor reducers is always provided with a safety
braking system, used to permanently maintain the winding element in upraised position,
thus avoiding the risk of accidentally starting the unwanted dangerous down travel
of the winding element in an uncontrolled way because of its own weight.
[0005] The most frequently used stop device consists in electromagnetic brakes or, altematively,
mechanical brakes. The mechanical brakes have the advantage of saving the electric
power necessary to activate the electromagnetic brakes and having overheating temperatures
lower than the temperatures normally reached by electromagnetic brakes in case of
prolonged use.
[0006] Instead of the above-mentioned braking systems, some tubular motor reducers for roller
shutters or sunblinds feature mechanical devices to make the motion transmission from
the electric motor to the power takeoff pin irreversible, so that the power takeoff
pin can only be dragged into rotation by the motor reducer, but not by the winding
element, whose weight actually generates a twisting moment that discharges on the
power takeoff pin.
[0007] The motion irreversibility devices comprise a pair of disks placed side by side that
feature two opposed pairs of front teeth that are mutually fixed and engaged so that
the first disk can drag the second one with the same transmission mode as in front
coupling joints.
[0008] The first disk - that is the disk directly dragged into rotation by the electric
motor - is splined at the end of the motor shaft that goes through a cylindrical collar
on which a cylindrical elicoidal spring is extemally inserted, whose ends are radially
bent out and engage from opposed direction one of the front teeth located on the first
disk.
[0009] When the first disk is dragged by the electric motor into rotation, the above-mentioned
spring is dragged into rotation in the same direction around its centering collar
and guide because of the interference between the two bent ends and the disk tooth
located between them.
[0010] It must be said that the thrust caused by the tooth on the bent end of the spring
determines a stress on the spring itself that tends to enlarge the spring tums, thus
practically annulling the friction between the tuming spring and its fixed centering
collar.
[0011] So, in this case, the spring represents no obstacle to the rotation of the first
disk.
[0012] Vice versa, the spring prevents the motion to be transmitted from the second to the
first disk, since the opposed pair of front teeth of the second disk engages with
the two bent ends of the spring from the outside. In this way the thrust caused by
both teeth on the bent end of the spring determines a stress on the spring itself
that tends to tighten the spring tums, thus stopping the spring around the centering
collar and block of the second disk.
[0013] In view of the above, it must be said that in the current models of tubular motor
reducers these mechanical irreversibility devices are always located between the electric
motor and the epicyclic reduction gear. This position causes considerable noise of
the motor reducer group since the vibrations from the electric motor are amplified
first by the irreversibility device and then by the epicyclic reduction gear.
[0014] Another inconvenience is represented by the position of the irreversibility device
between motor and reduction gear, resulting in a considerable loss of the motor rated
torque.
[0015] The purpose of the present invention is to eliminate both these inconveniences that
are typical of a tubular motor reducer for the handling of winding roller shutters
and sunblinds.
[0016] This objective has been reached by the present invention thanks to a different position
of the irreversibility mechanical device that is assembled inside the epicyclic reduction
gear, more exactly after the first step of the epicyclic reduction gear.
[0017] In this way the vibrations transmitted by the motor at the first step of the epicyclic
reduction gear are reduced by the irreversibility device itself, thus reducing the
noise with respect to the known tubular motor reducers.
[0018] It must also be noted that this position increases the overall yield of the transmission
system with an insignificant torque loss.
[0019] For clearer explication purposes, the description of the tubular motor reducer continues
with reference to the enclosed drawings whereby:
- Fig. 1 is an exploded lateral view of the various components of the tubular motor
reducer according to the present invention;
- Fig. 2 is an exploded axonometric view of the irreversibility mechanical device positioned
after the first step of a three-step epicyclic reduction gear;
- Fig. 3 is a cross-section of the three-step epicyclic reduction gear with an axial
plane incorporating the irreversibility device positioned between the first and the
second step.
[0020] With reference to the above mentioned figures, the tubular motor reducer according
to the present invention comprises an electric motor (1) able to rotate both clock
and counterclockwise located in extemal coaxial position with respect to a sleeve
(2) from which the pin (2a) for the power takeoff of the winding shaft of the roller
shutter or sunblind projects.
[0021] The motion transmission from the motor (1) to the power takeoff pin (2a) occurs through
an epicyclic reduction gear made up of three successive steps (3a, 3b and 3c) partly
housed inside the sleeve (2), whose internal surface features a crown gear (2b) that
engages with the crown wheels of the epicyclic reduction gear.
[0022] The tubular motor reducer also includes an irreversibility mechanical device made
up of a first disk (4) provided with an opposed pair of front teeth (4a), a second
disk (5) also provided with an opposed pair of front teeth (5a) and a cylindrical
helical spring (6) whose ends (6a) are drawn closer and radially bent out.
[0023] The two disks (4 and 5) are placed side by side so that the teeth of one disk engage
with the teeth of the other disk, with the same type of matching as in front coupling
joints. The two engaged pairs of front teeth contain the spring (6) between whose
bent ends (6a) one of the teeth (4a) of the first disk (4) is located, while the two
teeth (5a) of the second disk (5) are located outside and on opposite sides with respect
to the two bent ends (6a) of the spring (6).
[0024] The tubular motor reducer according to the present invention is characterized by
the fact that the pair of disks (4 and 5) with the spring (6) is incorporated into
the epicyclic reduction gear and more exactly inserted after the first reduction step
(3a).
[0025] At this purpose the tubular motor reducer according to the present invention includes
a secondary sleeve (7) used to contain the first step (3a) of the epicyclic reduction
gear that engages on the opening of the sleeve (2) inside which both the two disks
(4 and 5) with spring (6) and the second and third step of the reduction gear are
housed.
[0026] The internal wall of the secondary sleeve (7) also features a crown gear (7a) with
which the crown wheels of the first step (3a) engage, while the front of the sleeve
(7) features the centering collar (7b) of the spring (6).
[0027] The first disk (4) is splined at the end of the shaft (8) coming out of the first
step (3a), with the shaft that goes through and comes out of the collar (7b). The
second disk (5) features a central pinion (5b) that is used to transmit the motion
to the crown wheels of the second step (3b).
[0028] The second disk (5) features a central centering hole on the shaft (8) and is in
neutral with respect to the shaft, since the transmission from the shaft (8) to the
disk (5) occurs through the disk (4), whose front teeth (4a) drag the front teeth
(5a) of the disk (5) into rotation by means of the bent ends (6a) of the spring (6),
located between the teeth (4a and 5a) and on which the teeth (4a) directly discharge
their thrust.
[0029] Finally it must be said that the extemal surface of the collar (7b) features some
axial grooves (7c) used to contain the necessary quantity of grease to guarantee a
continuous effective lubrication of the sliding surface of the spring (6) that - as
mentioned before - rotates around the collar (7b).
[0030] The continuous automatic lubrication contributes to an even higher noise reduction
in the operation of the motor reducer according to the present invention.
1. Tubular motor reducer for the handling of roller shutters or sunblinds comprising:
- an electric motor (1) able to rotate both clock and counterclockwise located in
extemal coaxial position with respect to a sleeve (2) from which the pin (2a) for
the power takeoff projects and whose intemal surface features a crown gear (2b);
- a epicyclic reduction gear made up of one or more steps, housed in the sleeve (2),
whose crown wheels engage with the crown gear (2b);
- an irreversibility mechanical device made up of a first disk (4) provided with an
opposed pair of front teeth (4a), a second disk (5) also provided with an opposed
pair of front teeth (5a) and a cylindrical helical spring (6) whose ends (6a) are
drawn closer and radially bent out;
characterized by the fact that the pair of disks (4 and 5) with the spring (6) is
located in the epicyclic reduction gear and more exactly inserted after the first
reduction step (3a).
2. Motor reducer according to claim 1, comprising:
- a secondary sleeve (7) used to contain the first step (3a) of the epicyclic reduction
gear that engages on the opening of the sleeve (2) inside which both the pair of disks
(4 and 5) with spring (6) and the next reduction steps after the first step; being
provided that the intemal wall of the secondary sleeve (7) features a crown gear (7a)
on which the crown wheels of the first step (3a) engage, while the front of the sleeve
(7) features the centering collar (7b) of the spring (6);
- a first disk (4) that is splined at the end of the shaft (8) coming out of the first
step (3a), with the shaft that goes through and comes out of the collar (7a);
- a second disk (5) provided with a central pinion (5b) that transmits the motion
to the crown wheels of the second step (3b); being provided that the second disk (5)
features a central centering hole on the shaft (8) and is in neutral with respect
to the shaft.
3. Motor reducer according to the previous claims, characterized by the fact that the
external surface of the collar (7b) features some axial grooves (7c) used to contain
the necessary quantity of grease to guarantee a continuous effective lubrication of
the sliding surface of the spring (6).