Braking device for a movable door leaf and door closer having such a braking device

Abstract

A braking device for a movable door leaf comprises an electric braking motor to damp movement of the door leaf; a motor shaft coupleable with an axis of rotation of the door leaf; and a control unit to control the electric braking motor. A generator provides power to the control unit. A continuously variable transmission unit between the axis of rotation of the door leaf and either the motor shaft of the electric braking motor or the separate generator is controlled by a mechanical control such that the motor shaft of the electric braking motor and/or the separate generator, can be driven at a rotational speed independent of the rotational speed of the rotational axle of the door leaf. Also included is a door closer, having a rotatable door closer axis, coupleable with a door leaf, cooperating with a mechanical energy storage device, and a correspondingly designed braking device.

Claims

1. A braking device (18) for a movable door leaf (12), having an electric braking motor (24), operated as a generator, for generative damping of the movement of the door leaf 12), a motor shaft (26) of which is coupleable with an axis of rotation of the door leaf (12) by means of a transmission arrangement (28), and a control unit for controlling and/or regulating the electric brake motor (24), wherein, between the axis of rotation of the door leaf (12) and the motor shaft (26) of the electric braking motor (24) and/or between the axis of rotation of the door leaf (12) and a separate generator, serving as a power supply of the control unit, there is provided a continuously variable transmission unit (30), which is controlled and/or regulated by means of a preferably purely mechanical control such that the motor shaft (26) of the electric braking motor (24) and/or the separate generator can be driven at a rotational speed which is at least substantially independent of the rotational speed (ωm) of the rotational axle of the door leaf (12).

2. The braking device according to claim 1, wherein the motor shaft (26) of the electric braking motor (24) and the separate generator are drivable by means of the same continuously variable transmission (30) or by means of separate continuously variable transmission.

3. The braking device according to claim 1, wherein the continuously variable transmission unit (30) comprises a circumferential belt (36), extending between a drive shaft (32) and an output shaft (34) of the continuously variable transmission (39), the belt being guided by means of two bevel gears (38), fixedly rotatably connected to the drive shaft (32), and/or two bevel gears, fixedly rotatably connected to the to the output shaft (34), wherein, for the mechanical control of the ratio of the continuously variable transmission unit (30), with the belt (36) maintained tensioned, the axial distance between the two bevel gears (38) of at least one bevel gear pair (38′), fixedly rotatably connected to the drive shaft (32) or the output shaft (34), respectively, and thus the radial distance (R.sub.2) of the belt portion, looping around the respective bevel gear pair (38′), from the drive shaft (32) or the output shaft (34), respectively, is continuously variable.

4. The braking device according to claim 3, wherein the belt (36) is held under tension by a spring-loaded belt tensioning pulley (44).

5. The braking device according to claim 3, wherein at least one mass (m.sub.1, m.sub.2) is provided, which is put in rotation along with the drive or output shaft (32 or 34), which is radially displaceable by the centrifugal force acting on it and which is connected to at least one bevel gear (38), axially displaceable relative to the drive or output shaft (32 or 34) of the continuously variable transmission unit (30) and spring-loaded into an initial position, of a bevel gear pair (38′) with axially continuously variable distance, such that the axially displaceable bevel gear (38) is movable out of its initial position against the spring force by means of the centrifugal force acting on the mass (m.sub.1, m.sub.2) in order to vary the axial distance between the two bevel gears (38) of the bevel gear pair (38′).

6. The braking device according to claim 5, wherein a respective bevel gear (38), axially displaceable relative to the drive or output shaft (32 or 34) of the continuously variable transmission (30), is coupled with a respective mass (m.sub.1, m.sub.2) by means of a cable (52).

7. The braking device according to claim 6, wherein the cable (52) is guided between a respective bevel gear (38), axially displaceable relative to the drive or output shaft (32 or 34) of the continuously variable transmission (30), and a respective mass (m.sub.1, m.sub.2) associated therewith by means of at least one deflection roller (50).

8. The braking device according to claim 7, wherein the deflection roller (50) has a variable radius over its circumference.

9. The braking device according to claim 5, wherein a respective bevel gear (38), axially displaceable relative to the drive or output shaft (32 or 34) of the continuously variable transmission (30), of at least one bevel gear pair (38′) with axially continuously variable distance is coupled with a respective mass (m.sub.1, m.sub.2) by means of a lever arrangement (56).

10. The braking device according to claim 1, wherein a respective mass (m.sub.1, m.sub.2) is radially displaceable guided by a guide tube (48), which is rotatably fixedly connected to the drive or output shaft (32 or 34) of the continuously variable transmission unit (30).

11. The braking device according to claim 1, wherein a respective bevel gear (38), axially displaceable relative to the drive or output shaft (32 or 34) of the continuously variable transmission (30), of at least one bevel gear pair (38′) with axially continuously variable distance is designed as a ring gear with a conical jacket (58), which is spring-loaded into an initial position, in which it abuts with its open side against a wall (60) that is rotationally fixedly as well as axially fixedly connected with the drive or output shaft (32 or 34), or has a minimum distance from this wall (60), and a respective mass, arranged between the ring gear (38) and the wall (60), is displaceably guided along the wall (60) by the spring-loaded ring gear (38), abuts against the inside of the conical jacket (58) of the ring gear (38), on the one hand, and abuts against the wall (60), on the other hand.

12. The braking device according to claim 1, wherein the bevel gear surfaces of the two bevel gears (38) of a respective bevel gear pair (38′) with axially continuously variable distance has a course deviating from a linear course, preferably an at least substantially square course.

13. The braking device according to claim 1, wherein the belt (36) is guided by means of a bevel gear pair (38′) with axially continuously variable distance, rotatably fixedly connected to the drive shaft (32) or the output shaft (34) of the continuously variable transmission unit (30), on the one hand, and by means of a cylindrical belt pulley (44), rotatably fixedly connected to the output shaft (32) or the drive shaft (34) of the continuously variable transmission unit (30), on the other hand.

14. The braking device according to claim 1, wherein the belt (36) is guided by means of a first bevel gear pair (38′), rotatably fixedly connected to the drive shaft (32) of the continuously variable transmission unit (30), on the one hand, and by means of another bevel gear pair (38′), rotatably fixedly connected to the output shaft (34) of the continuously variable transmission unit (30), on the other hand, and at least one of the two bevel gear pairs (38′) is provided as bevel gear pair with axially continuously variable distance.

15. The braking device according to claim 1, wherein both bevel gears (38) of at least one bevel gear pair (38′) are each axially displaceable relative to the drive or output shaft (32 or 34) of the continuously variable transmission (30), spring-loaded into an initial position, and, in order to vary the axial distance between the two bevel gears (38), are displaceable from an initial position against the spring force by means of a centrifugal force, applied by a mass (m.sub.1, m.sub.2), put into rotation along with the drive or output shaft (32 or 34).

16. The braking device according to claim 1, wherein the gear assembly (28), provided between the axis of rotation of the door leaf (12) and the braking motor (24), also comprises a transmission unit (62) with fixed ratio, arranged between the axis of rotation of the door leaf (12) and the continuously variable transmission unit (30).

17. The braking device according to claim 1, wherein, the gear assembly (28), provided between the axis of rotation of the door leaf (12) and the braking motor (24), also comprises a transmission unit (64) with fixed ratio, arranged between the continuously variable transmission unit (30) and the braking motor (24).

18. A door closer (10) having a rotatable door closer axis (14), coupleable with a door leaf, cooperating with a mechanical energy storage device (12), and a braking device (16), wherein the braking device (18) is designed in accordance to claim 1.

19. The door closer according to claim 18, wherein the braking device (18) is coupleable with the axis of rotation of the door leaf (12) by means of the door closer axle (16).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic block diagram of an exemplary embodiment of a door closer according to the invention with an exemplary embodiment of a braking device according to the invention,

(2) FIG. 2 shows a schematic plan view of an exemplary embodiment of a continuously variable transmission unit of the braking device according to the invention,

(3) FIG. 3 shows a schematic side view of the continuously variable transmission unit according to FIG. 2,

(4) FIG. 4 shows a schematic representation of the mechanical control of the ratio of the continuously variable transmission unit according to FIG. 2,

(5) FIG. 5 shows a schematic frontal view of the bevel gear of the bevel gear pair of the continuously variable transmission unit of FIG. 2, axially displaceable relative to the drive shaft, with masses, associated with the axially displaceable bevel gear, in a respective guide tube,

(6) FIG. 6 shows a diagram showing the dependence of the radial distance of the belt portion, looping around the bevel gear pair of the continuously variable transmission unit according to FIG. 2, from the axle of the drive shaft on the displacement of the axially displaceable bevel gear,

(7) FIG. 7a shows a schematic representation of the minimum axial distance between the two bevel gears of the continuously variable transmission unit according to FIG. 2 and of the corresponding maximum radial distance of the belt portion, looping around the bevel gear pair, from the axle of the drive shaft at a minimum radial displacement of the associated masses.

(8) FIG. 7b shows a schematic representation of the maximum axial distance between the two bevel gears of the continuously variable transmission unit according to FIG. 2 and of the corresponding minimum radial distance of the belt portion, looping around the bevel gear pair, from the axle of the drive shaft at a maximum radial displacement of the associated masses,

(9) FIG. 8 shows a diagram in which the speed of output shaft as a function of the speed of the drive shaft in a conventional transmission is compared with an exemplary embodiment with a mechanically controlled continuously variable transmission unit according to the invention of the brake device according to the invention,

(10) FIG. 9a shows a schematic representation of a bevel gear with a bevel gear surface, having a linear course,

(11) FIG. 9b shows a schematic representation of an exemplary embodiment of a bevel gear according to the invention with a bevel gear surface, having a quadratic course, deviating from a linear course,

(12) FIG. 10 shows a schematic representation of an exemplary embodiment of the continuously variable transmission unit of the braking device according to the invention, in which the belt is guided with axially continuously variable distance on both, the drive side and the output side, by means of a bevel gear pair each, and both bevel gears of the two bevel gear pairs are each axially displaceable relative to the drive or output shaft and are spring-loaded in an initial position,

(13) FIG. 11a shows schematic diagram of an exemplary cylindrical deflection roller of the braking device according to the invention,

(14) FIG. 11b shows a schematic representation of a modified exemplary deflection roller of the braking device according to the invention, having a variable radius over its circumference,

(15) FIG. 12a shows a schematic representation of an exemplary coupling of a respective axially displaceable bevel gear of the braking device according to the invention with a respective mass by means of a cable, guided around a deflection roller,

(16) FIG. 12b shows a schematic representation of an alternative exemplary coupling of a respective axially displaceable bevel gear of the braking device according to the invention with a respective mass by means of a lever arrangement, and

(17) FIG. 13 shows a schematic representation of a bevel gear, axially adjustable relative to the drive or output axle, of a further exemplary embodiment of the continuously variable drive unit of the braking device according to the invention, in which the bevel gear is designed as a ring gear and the associated masses are radially displaceable along a wall, that is rotationally fixedly as well as axially fixedly connected to the drive or output axle, respectively.

DETAILED DESCRIPTION

(18) FIG. 1 shows, in the form of a schematic block diagram, an exemplary embodiment of a door closer 10 according to the invention, having a rotatable door closer axle 16, which is coupleable to a door leaf 12 and interacts with a mechanical energy storage device 14, such as a spring unit, and an exemplary embodiment of a brake device 18 according to the invention.

(19) In the present embodiment, the braking device 18 is coupleable with the door leaf 12 and its axis of rotation by means of the door closer axle 16 and a slide lever, a linkage 20, or the like. Between the door closer axle 16 and the mechanical energy storage device 14, a door closer transmission unit 22, comprising a cam or the like, may be provided.

(20) The braking device 18 comprises an electric braking motor 24 operated as a generator, for generative damping of the movement of the door leaf 12, the motor shaft 26 of which is coupleable to the door leaf 12 or its axis of rotation by means of a gear assembly 28. At the same time, the braking motor 24 may be designed as a generator for supplying power to a control unit provided for controlling the braking motor 24 and be provided, for example, with a generator winding. Alternatively, a separate generator may be provided, which can then be driven, in particular, by means of the same transmission arrangement 28 as the braking motor 24.

(21) The transmission assembly 28 comprises a continuously variable transmission unit 30, which is controlled and/or regulated by a purely mechanical control in such a manner that the motor shaft 26, and optionally a separate generator, can be driven with a speed ω.sub.m that is at least substantially independent of the rotational speed of the axis of rotation of the door leaf 12 or the rotational speed of door closers axle 16.

(22) As can be seen from FIGS. 2 to 13, the continuously variable transmission unit 30 of the various exemplary embodiments of the brake device 18 according to the invention in each case comprises a belt 36, extending circumferentially between a drive shaft 32 and an output shaft 34 of the continuously variable transmission unit 30, guided by means of two bevel gears 38, rotatably fixedly connected with the drive shaft 32, and/or two bevel gears, rotatably fixedly connected with the output shaft 34. For the mechanical control of the ratio of the continuously variable transmission unit 30 here, with the belt 36 kept tensioned, the axial distance between the two bevel gears 38 of at least one bevel gear pair 38′, rotatably fixedly connected with the drive shaft 32 or the output shaft 34, and thus the radial distance R.sub.2 of the belt portion, looping around the respective bevel gear pair 38′, from of the axle of the drive shaft 32 or the output shaft 34 is continuously variable. As can be seen from FIG. 3, the belt 36 can in each case be kept tensioned by a belt tensioning pulley 44 being spring-loaded, for example, by a spring unit 42.

(23) FIG. 2 to 5 show an exemplary embodiment of a continuously variable transmission unit 30 of the braking device 18 according to the invention, in which the belt 36 is guided by means of a bevel gear pair 38′ with axially continuously variable distance, rotationally fixedly connected to the drive shaft 32 of the continuously variable transmission unit 30, on the one hand, and by means of a cylindrical belt pulley 54, rotationally fixedly connected to the output shaft 34 of the continuously variable transmission unit 30, on the other hand.

(24) In this case, only one of the two bevel gears 38 of the bevel gear pair 38′ with axially continuously variable distance relative to drive shaft 32 of the continuously variable transmission unit 30 is axially displaceable and spring-loaded into an initial position. To vary the axial distance between the two bevel gears, the axially displaceable bevel gear 38 is movable against the spring force out of its initial position by the centrifugal force acting on the at least two masses m.sub.1, m.sub.2, put into rotation along with the drive shaft 32. As can be seen in particular from FIG. 4, in the present case the right bevel gear 38, for example, of the bevel gear pair 38′ is axially displaceable relative to the drive axle 32 and moveable out of its initial position against the force of a spring unit 46 by the centrifugal force acting on the masses m.sub.1, m.sub.2.

(25) As can be seen in particular from FIGS. 4 and 5, the masses m.sub.1, m.sub.2 in the present case, associated with bevel gear 38, axially displaceable relative to the drive shaft 32, guided radially slidably, for example, in a radial guide tube 48. rotationally fixedly connected to the drive shaft 32 of the continuously variable transmission unit 30. The associated masses m.sub.1, m.sub.2 axially displaceable relative to the drive shaft 32 bevel gear 38, in the present case are each coupled with the bevel gear 38 by means of a cable 52 guided around a deflection roller 50.

(26) The mechanical control of the axial position of a respective bevel gear 38, axially displaceable relative to the drive shaft 32, is accordingly accomplished with the aid of centrifugal force, which acts on the masses m.sub.1, m.sub.2 acts and is proportional to the square of the rotational speed of these masses or the drive shaft 32. When the drive shaft 32 of the continuously variable transmission unit 30 rotates with the rotational speed ω.sub.2, the centrifugal force that acts on the each of the masses m.sub.1 and m.sub.2 at a relative radial displacement x of the masses with respect to their minimum deflection is
F.sub.Z1/2=m.sub.1/2ω.sub.2.sup.2x.

(27) The centrifugal force increases quadratically with increasing speed of rotation ω.sub.2 of the drive shaft 32 of the continuously variable transmission unit 30, that is, it is proportional to ω.sub.2.sup.2, and displaces the masses m.sub.1 and m.sub.2 radially outward. At the same time, due to the corresponding displacement of the respective bevel gear 38, spring unit 46 spring-loading this bevel gear is tensioned. In the representation according to FIG. 4, the right bevel gear 38 is now displaced to the right against the spring force until an equilibrium between the spring force 46 F.sub.F, generated by the spring unit, and the centrifugal force F.sub.Z, acting on the masses m.sub.1 and m.sub.2, is established. The following relationship holds for this equilibrium:
F.sub.F=c(x+x.sub.0)=F.sub.Z=mω.sub.2.sup.2(x+r.sub.0), m=m.sub.1+m.sub.2,

(28) where this relationship is true for 0≤x≤r.sub.1−r.sub.0 and m is the sum of the masses m.sub.1 and m.sub.2, c is the spring stiffness of the spring unit 46, cx.sub.0 is the spring bias of the spring unit 46, x is the radial displacement of a respective mass m.sub.1, m.sub.2 with respect to their initial position, r.sub.0 is the radial distance of a respective mass m.sub.1, m.sub.2, occupying its initial position, to the axle of the drive shaft 32, and r.sub.1 is the radial distance of the masses m.sub.1, m.sub.2 to the axle of the drive shaft 32 at their maximum displacement.

(29) $\mathrm{For}$$m{\omega }_2^2\left(x+r_0\right)>c\left(x+x_0\right)$$\mathrm{or}$${\omega }_2>\sqrt{\frac{c\left(x+x_0\right)}{m\left(x+r_0\right)}}=\omega 20$

(30) the bevel gear 38, being axially displaceable relative to the drive shaft 32, is displaced by the path x to the right in the representation according to FIG. 4, wherein this path x is determined by the following relationship:

(31) $x=\frac{m{\omega }_2^2{r}_0-{\mathrm{cx}}_0}{c-m{\omega }_2^2}.$

(32) If α is the slope of the axially displaceable bevel gear 38, the maximum radial distance R.sub.20 of the belt portion, looping around the bevel gear 38, from the axle of the drive shaft 32 of the continuously variable transmission unit 30 decreases, as per the representation according to FIG. 6, to the radial distance R.sub.2, determined by the relationship
R.sub.2=R.sub.20−x tan x.

(33) Since the belt 36, on its left side in FIG. 2, runs on a bevel gear 38, axially fixedly connected to the drive shaft 32, with the same slope α, the radial distance R.sub.20 decreases only by half so that, the relationship holds for the resulting reduced radial distance R.sub.2 of belt portion, looping around the respective bevel gear pair 38′, from the axle of the drive shaft:
R.sub.2=R.sub.20−1/2x tan x

(34) With a radial displacement of the masses m.sub.1 and m.sub.2 radially outward by the path x=r.sub.1−r.sub.0, the masses m.sub.1 and m.sub.2 abut against the end of the guide tube 48. Until such abutment of the masses m.sub.1 and m.sub.2 against the end of the guide tube 48, it applies that, with increasing x, the radial distance R.sub.2 belt portion, looping around the respective bevel gear pair 38′, from the axle of the drive shaft 32 of the continuously variable transmission unit 30 decreases. The respective excess belt length is compensated by the spring-loaded belt tensioning pulley 44. The spring constant of this spring unit 42, spring-loading the belt tensioning pulley 44, is taken into consideration in the aforementioned spring stiffness c.

(35) For example, considering a concrete example with the following values,

(36) TABLE-US-00001 m.sub.1 + m.sub.2 = m 0.07 kg r0 0.005 m r1 0.011 m c 3000 N/m x0 0.0007 m R20 0.01 m R30 0.01 m α 65°

(37) according to FIG. 7a, for a minimum axial displacement of the respective bevel gear 38 of x=0 mm, a radial distance R.sub.2 belt portion, looping around the respective bevel gear pair 38′, from the axle of the drive shaft 32 of 10 mm and, according to FIG. 7b, at a maximum axial displacement of the respective bevel gear 38 by x=6 mm, there results a radial distance R.sub.2 of the belt portion, looping around the respective bevel gear pair 38′, from the axle of the drive shaft 32 of 3.6 mm. For the present example, the following radial distances R.sub.2 of the belt portion, looping around respective bevel gear pair 38′, from the drive shaft 32, thus result:
R.sub.2(x=0 mm)=10 mm
R.sub.2(x=6 mm)=3.6 mm.

(38) The resulting ratio SL of the continuously variable transmission unit 30 according to the invention can be taken from FIG. 8, in which the rotational speed n.sub.3 of the output shaft 34 is shown above the speed n.sub.2 of the drive shaft 32 of the continuously variable transmission unit 30.

(39) For

(40) $n_2<740\frac{1}{\min },$
the force of the spring unit 46 spring-loading the axially adjustable bevel gear 38 in question in its initial position is greater than the centrifugal force so that x=0 is true. The continuously variable transmission unit 30, in this case, behaves like a conventional transmission with the ratio SL′ (cf. FIG. 8), for which the following applies:

(41) $n_3=\frac{R_{20}}{R_{30}}{n}_2,$

(42) with R.sub.20=radius of a respective bevel gear 38 R.sub.30=radius of the belt pulley 54

(43) For

(44) $740\frac{1}{\mathrm{mm}}\le n_2<2275\frac{1}{\mathrm{mm}},$
the centrifugal force greater than the force of the spring unit 46, spring-loading the axially displaceable bevel gear 38. The masses m.sub.1 and m.sub.2 move radially outward and reduce the radial distance R.sub.2 of the belt portion, looping around the bevel gear pair 38′ with axially variable distance, with respect to the radius R.sub.20 of a respective bevel gear 38, so that the following relationship holds for the rotational speed n.sub.3 of the output shaft 34 of the continuously variable transmission unit 30:

(45) $n_3=\frac{R_{20}-\frac{1}{2}x\tan \alpha }{R_{30}}{n}_2.$

(46) At a speed n.sub.2 of the drive shaft 32 of the continuously variable transmission unit 30 of

(47) $2275\frac{1}{\mathrm{mm}},$
the two masses m.sub.1 and m.sub.2 abut against the ends of the guide tube 48 so that x no longer changes. The continuously variable transmission unit 30 now behaves like a conventional transmission, but with a smaller reduction, which is determined by the following relationship:

(48) $n_3=\frac{R_{20}-\left(r_1-r_0\right)\tan \alpha }{R_{30}}{n}_2.$

(49) Overall, the continuously variable transmission unit 30 in the present embodiment thus reduces the dynamic response at the output by a factor of 3.

(50) Starting at a speed n.sub.2 of about

(51) $1000\frac{1}{\min }$
up to about

(52) 0$3000\frac{1}{\mathrm{mm}}$
at the input or the drive shaft 32, the speed n.sub.3 at the output or the output shaft 34 of the continuously variable transmission unit 30 is substantially constant, that is, at least substantially independent of the speed of the drive shaft 32 of the continuously variable transmission unit 30.

(53) An optimization of this continuously variable transmission unit 30 can be achieved, as shown in FIG. 9, for example, if the bevel gear surfaces of the two bevel gears 38 of a respective bevel gear pair 38′ with axially continuously variable distance deviate from a linear course (cf. FIG. 9a), preferably having an at least substantially quadratic course (cf. FIG. 9b). The correspondingly optimized transmission behaviour of the continuously variable transmission unit 30 is shown by the curve SL.sub.opt in FIG. 8.

(54) For example an embodiment of the continuously variable transmission unit 30 of the brake device 18 according to the invention is conceivable as well in which, in the embodiment of FIG. 4, the left bevel gear 38 of the bevel gear pair 38′ is also axially displaceable relative to the output shaft 32 of the continuously variable control unit 30 and is spring-loaded by a spring unit 46 in an initial position, wherein the axial displacement of the bevel gear 38 is again controlled purely mechanically by means of the centrifugal force acting on the masses m.sub.1, m.sub.2. The design in question thus corresponds to that for the other bevel gear 38 of the bevel gear pair 38′.

(55) Such an embodiment with two of the continuously variable transmission unit 30 relative to the drive shaft 32 brings along with it the two advantages, with respect to a variant with only one axially displaceable bevel gear, wherein the belt 36 does not move axially, while, in the first embodiment, the belt moves axially by the path x/2, and, in this second embodiment, the reduction is twice as big, wherein the rotational speed n.sub.3 of the output shaft 34 of the continuously variable transmission unit 30 is determined by the following relationship:

(56) $n_3=\frac{R_{20}-x\tan \alpha }{R_{30}}.$

(57) FIG. 10 shows a further exemplary embodiment of the continuously variable transmission unit 30 of the brake device 18 according to the invention, in which the belt 36 is guided, on both the drive side and the output side, by means of a bevel gear pair 38′ each, with axially continuously variable distance, and both bevel gears 38 of the two respective bevel gear pairs 38′ are axially displaceable relative to the drive or output shaft 32 or 34, respectively, of the continuously variable transmission unit 30 and spring-loaded, in an initial position, by a respective spring unit 46.

(58) In the present embodiment, the two bevel gears 38 on the output side of the continuously variable transmission unit 30 have the same dimensions as those on the drive side. Their axial position is controlled by the two associated spring units 46, for example, provided as return springs, and by the belt tension. If the centrifugal force acting on the respective masses pulls apart the two bevel gears 38 on the drive side of the continuously variable transmission unit 30, then the two spring units or return springs 46 on the output side of the continuously variable transmission unit 30 push the bevel gears 38 together by the same axial path x. The previously provided belt tensioning pulley can be omitted here. The following applies for the reduction in the present case:

(59) $n_3=\frac{R_{20}-x\tan \alpha }{R_{30}+x\tan \alpha }{n}_2.$

(60) For further optimization of the ratio of the continuously variable transmission unit 30, a deflection roller 50 may be provided, for example, as shown in FIG. 11, having a radius that is variable over its circumference.

(61) As can be seen from FIG. 12, a lever assembly 56 may be provided, for example, instead of a cable 52, guided around a deflection roller 50, for coupling a respective axially displaceable bevel gear 38 of the continuously variable transmission 80 with a respective mass m.sub.1, m.sub.2.

(62) FIG. 13 shows a further exemplary embodiment of a bevel gear, which is axially displaceable relative to the drive or output axle 32 or 34 of the continuously variable transmission unit 30 and which has a displacement that is mechanically controlled by the centrifugal force.

(63) In this case, a respective bevel gear 38, axially displaceable relative to the drive or output shaft 32 or 34 of the continuously variable transmission 30 is embodied as a ring gear with a conical jacket 58, which is spring-loaded into an initial position by a spring unit 46, in which it abuts with its open side against a wall 60, which is both, rotationally fixedly and axially fixedly, connected with the drive or output shaft 32 or 34, or has a minimum distance from this wall 60. In addition, at least two masses m are arranged between the ring gear 38 and the wall 60 such that a respective mass m abuts against the inside of the conical jacket 58 of the ring gear 38, on the one hand, and abuts against the wall 60, on the other hand, by the spring-loaded ring gear 38 and is guided radially displaceably along the wall 60.

(64) When the speed ω.sub.2 of the drive shaft 32 of the continuously variable transmission unit 30 increases, the masses m move radially outward along the wall 60 and push the ring gear 38 away from the wall 60 against the force of the spring unit 46, or to the left in the representation according to FIG. 13.

(65) As can be seen from FIG. 1, the gear assembly 28 of the brake device 18 according to the invention may also comprise, for example, a transmission unit 62 with fixed ratio, arranged between the rotational axle of the door leaf 12 and the door closer axle 16 and the continuously variable transmission unit 30, and/or transmission unit 64 with fixed ratio, arranged between the continuously variable transmission unit 30 and the braking motor 24.

LIST OF REFERENCE SYMBOLS

(66) 10 Door closer 12 Door leaf 14 Mechanical energy storage device 16 Door closer axle 18 Braking device 20 Slide lever, linkage 22 Door closer transmission unit 24 Braking motor 26 Motor shaft 28 Transmission arrangement 30 Continuously variable transmission unit 32 Drive shaft 34 Output shaft 36 Belt 38 Bevel gear 38′ Bevel gear pair 42 Spring unit 44 Belt tensioning pulley 46 Spring unit 48 Guide tube 50 Deflection roller 52 Cable 54 Belt pulley 56 Lever arrangement 58 Jacket 60 Wall 62 Transmission unit with fixed ratio 64 Transmission unit with fixed ratio F.sub.F Spring force F.sub.Z Centrifugal force R.sub.2 Radial distance of the belt portion, looping around a respective bevel gear pair, from the axle of the drive or output shaft of the continuously variable transmission unit R.sub.20 Radius of a respective bevel gear or maximum radial distance of a belt portion, looping around a respective bevel gear bevel gear pair belt, from the axle of the drive shaft of the continuously variable transmission unit SL Ratio of the continuously variable transmission unit SL.sub.opt Optimized ratio of the continuously variable transmission unit m Mass m.sub.1 Mass m.sub.2 Mass ω.sub.1, n.sub.1 Rotating speed of the door closer axle ω.sub.2, n.sub.2 Rotating speed of the drive shaft of the continuously variable transmission unit ω.sub.3, n.sub.3 Rotating speed of the output shaft of the continuously variable transmission unit ω.sub.m Rotating speed of the motor shaft