Superposition gear

Abstract

The invention relates to a superposition gear (1), in particular for a grinding unit, having a mechanical power branch comprising a gear input (1a) which can be coupled to a drive machine (1c), a gear output (1b) which can be coupled to an output machine, in particular the grinding unit, and at least one epicyclic gearing stage (3, 4, 5), via which the gear input (1a) is brought into a transmitted rotary connection with the gear output (1b) or can at least be brought into a transmitted rotary connection therewith, wherein a gear (5a) of the epicyclic gearing stage (3, 4, 5) is fixed by one or more hydraulic overload clutches (2), and the hydraulic overload clutch or each of the plurality of hydraulic overload clutches (2) has a hydraulic machine (2a), the drive shaft (2c) of which is in direct or indirect engagement with the gear (3a), and a pressure limiting valve (2b) which fluidically connects a pressure side of the hydraulic machine (2a) to a suction side of the hydraulic machine (2a).

Description

[0001] Superposition gear

[0002] Description

[0003] The present invention relates to a superposition gear.

[0004] Background of the invention

[0005] In a shredder, especially a mobile one, recycling or composting materials to be shredded are continuously fed into a machine room and "shredded" by shredder or crushing rollers. The shredder rollers are driven, for example, by an electric motor via a multi-stage epicyclic gear system. The latter reduces the speed of the electric motor and increases the torque. The epicyclic gear system has a constant gear ratio. Thus, with a constantly rotating electric motor, the crushing rollers move at the same speed and in the same direction. Other grinders operate in a similar way.

[0006] To protect the drive machine from damage in the event of a transmission output blockage and the resulting overload, a safety clutch, such as a slip clutch or a hydrodynamic clutch, can be used. Such a clutch disconnects the transmission input from the transmission output in the event of an overload, particularly when the torque to be transmitted exceeds a permissible limit. This also allows the drive machine to continue rotating without the transmission output and the connected machine having to rotate.

[0007] Disclosure of the invention According to the invention, a superposition gear with the features of patent claim 1 is proposed. Advantageous embodiments are the subject of the subclaims and the following description.

[0008] The invention is based on a superposition gear unit with a mechanical power branch, comprising a gear input that can be coupled to a drive machine, a gear output that can be coupled to a driven machine or driven machine, and a planetary gear stage via which the gear input is in a geared rotary connection with the gear output or can at least be brought into such a connection. The driven machine is a machine with a rotating input shaft, in particular a grinder such as a shredder or chopper.

[0009] A blockage of the gearbox output, which can occur, for example, when objects become jammed in a shredder, can lead to the drive motor, for example an electric motor, becoming overloaded because it continues to try to rotate the drive train due to the inertia of the drive components. To enable further rotation of the gearbox input in the event of an overload, a gear, in particular a ring gear, of the epicyclic gear stage is held in place by one or more hydraulic overload clutches, which open in the event of an overload. The epicyclic gear stage is, in particular, a planetary gear stage with a sun gear, one or more planet gears and a ring gear. For example, in what is known as two-shaft operation, the ring gear can be held in place and rotation of the sun gear can be translated into rotation of a planet gear carrier (web).

[0010] One or each of the several hydraulic overload clutches comprises a hydraulic machine, e.g., a hydraulic pump, whose drive shaft is in direct or indirect engagement with the fixed gear of the epicyclic gear stage, and a pressure relief valve that fluidly connects a pressure side of the hydraulic machine to a suction side of the hydraulic machine. The trigger pressure of the pressure relief valve thus determines the torque that can be supported by the hydraulic machine.

[0011] By using a pressure relief valve that connects the pressure side and the suction side of the hydraulic machine, if the pressure in the hydraulic machine increases excessively due to the buildup of torque in the epicyclic gear system, the hydraulic fluid can be pumped from the pressure side to the suction side by opening the pressure relief valve when a predetermined pressure is reached or exceeded. This allows the fixed gear of the epicyclic gear system to rotate, thus allowing the drive component (gearbox input) to rotate while the gearbox output is stationary, for example, due to a blockage of the shredder machine, until the drive component comes to a standstill. The advantage of such a hydraulic overload clutch over conventional slip clutches is its wear-free design and adjustment precision.Furthermore, the proposed hydraulic overload clutch has the advantage of higher efficiency compared to conventional hydrodynamic clutches, as no slippage is required. Furthermore, the design of such a hydraulic overload clutch is less complex, which can reduce manufacturing costs and simplify maintenance and repair.

[0012] In one embodiment, at least one hydraulic machine of the one or more hydraulic overload clutches has a speed sensor that determines the speed of the at least one hydraulic machine. Since the fixed wheel of the epicyclic gear train is supported by the hydraulic machine, it can be easily determined by determining the speed of the hydraulic machine that an overload is present if the speed signal indicates rotation at a speed that is above a predetermined limit (e.g., zero) because the hydraulic machine is spinning. In this case, a signal can be output to the drive component to stop it, whereby the drive component can be protected from further damage if an overload occurs.

[0013] In one embodiment, the superposition gear has several, in particular two or three, hydraulic overload clutches. Each of the hydraulic machines of the plurality of overload clutches is assigned its own pressure relief valve, which connects the pressure side of the hydraulic machine with the suction side of the same hydraulic machine. The axes of rotation and / or the engagements of each of the plurality of drive shafts are arranged, in particular, evenly distributed along a circumference of the fixed wheel. With two hydraulic machines, they are arranged, in particular, diametrically, and with three hydraulic machines, in particular, at a circumferential angular distance of 120°. By using several hydraulic machines and pressure relief valves, the fixed wheel can be loaded more symmetrically with respect to the transverse forces resulting from the engagements, which enables a simplified, less complex, and more cost-effective bearing of the fixed wheel.Furthermore, it is possible to make the hydraulic machines and pressure relief valves smaller, as opposed to using just one hydraulic machine, since the load is distributed across several hydraulic machines, which further saves costs and reduces the size of the superposition gear.

[0014] In a further embodiment, the axis of rotation of one or each of the multiple drive shafts is arranged within a diameter of the fixed gear. This allows the installation space to be reduced in the radial direction, particularly in contrast to arrangements in superposition gears, in which an external toothing of the fixed gear engages or meshes with an external toothing of a pinion of the drive shaft of the hydraulic machine via another externally toothed intermediate gear, which results in a large installation space in the radial direction.

[0015] In one embodiment, one or each of the drive shafts is in direct or indirect engagement with the fixed wheel on an inner circumference. For this purpose, one or each of the drive shafts of the hydraulic machines has, in particular, external gearing, with the engagement being formed by the external gearing and an internal gearing of the fixed wheel. The external gearing of the drive shaft can be implemented, in particular, by a pinion connected in a rotationally fixed manner to the drive shaft. This allows the hydraulic machines to be arranged within the diameter of the fixed wheel in a simple and cost-effective manner, which reduces the required installation space.

[0016] In one embodiment, one or at least one of the hydraulic machines has an adjustable displacement volume. This allows the torque that can be supported by the hydraulic machine(s) to be flexibly varied.

[0017] In one embodiment, the displacement volume can be adjusted to zero, which corresponds to releasing the held gear even without overload. This also allows the direction of rotation of the drive shafts to be reversed. In this way, without complicated switching and clutch devices, the transmission output shaft can rotate in the opposite direction, and jamming or entanglement can be resolved. In one embodiment, the mechanical power branch has several, for example, two or three, epicyclic gear stages. By using several epicyclic gears, the transmission ratio, in particular the reduction ratio, of the superposition gear can be increased.

[0018] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0019] The invention is illustrated schematically in the drawing using exemplary embodiments and is described in detail below with reference to the drawing.

[0020] Character description

[0021] Figure 1 shows a transmission diagram of an embodiment of the superposition gear with a hydraulic overload clutch; and

[0022] Figure 2 shows a gear diagram of an embodiment of the superposition gear with two hydraulic overload clutches.

[0023] Detailed description of the drawing

[0024] Figure 1 shows a transmission diagram of an embodiment of a superposition gearbox 1 with a hydraulic overload clutch 2, which includes a hydraulic machine 2a. The superposition gearbox 1 serves to transmit power from a drive machine 1c, which is in particular an electric motor, to one or more output machines (not shown), for example, grinding mills such as shredders. For this purpose, the superposition gearbox 1 has a transmission input 1a, to which the drive machine 1c is coupled, and a transmission output 1b, to which an input shaft of the output machine can be coupled, in particular via an annular flange (not shown).To transmit the torque from the drive motor 1c to the transmission output 1b, the superposition gearbox 1 comprises two power branches, a mechanical power branch in the form of an epicyclic gear with a first epicyclic gear stage 3, a second epicyclic gear stage 4 and a third epicyclic gear stage 5, and a hydraulic power branch with the hydraulic overload clutch 2.

[0025] The mechanical power branch does not necessarily have to have three epicyclic gear stages 3, 4, and 5, but can have only the first epicyclic gear stage 3, two, or more than three epicyclic gear stages. By using additional epicyclic gear stages, the transmission ratio of the superposition gear 1 can be increased.

[0026] The epicyclic gear stages 3, 4, 5 each have a sun gear 3b, 4b, 5b. The sun gear 3b of the first epicyclic gear stage 3 is coupled to the transmission input 1a, while the sun gears 4b, 5b of the second and third epicyclic gear stages 4, 5 are coupled to output shafts 3e, 4e of the respective upstream epicyclic gear stages 3, 4. Planet gears 3c, 4c, 5c engage or mesh with the sun gears 3b, 4b, 5b radially on the outside. The number of planet gears 3c, 4c, 5c per gear stage allows a load to be distributed over a larger number of tooth meshes, thereby increasing the transmittable torque. The planet gears 3c, 4c, 5c of a planetary gear stage 3, 4, 5 are typically arranged evenly distributed in the circumferential direction around the respective sun gear 3b, 4b, 5b of the respective planetary gear stage 3, 4, 5.

[0027] Furthermore, each epicyclic gear stage 3, 4, 5 has a planet carrier 3d, 4d, 5d on which the planet gears 3b, 4b, 5b of the respective epicyclic gear stage 3, 4, 5 are mounted and which connects the planet gears 3b, 4b, 5b of the respective epicyclic gear stage 3, 4, 5. The planet carrier 3d, 4d, 5d also forms the output shaft 3e, 4e, 5e of the respective epicyclic gear stage 3, 4, 5, via which the power is transmitted to the next epicyclic gear stage 4, 5 or the transmission output 1b.

[0028] The planet gears 3c of the first epicyclic gear stage 3 further engage radially outwardly with a ring gear 3a, and the planet gears 4c, 5c of the second and third epicyclic gear stages 4, 5 each engage radially outwardly with a ring gear (not shown) or one of two tracks of a second ring gear 4a. The ring gear 3a is rotatably mounted via a bearing 3f. The second ring gear 4a is a fixed ring gear, which is supported, for example, on the housing. The ring gear 3a has a second track with which the hydraulic overload clutch 2 engages. Figure 1 shows, by way of example, precisely one hydraulic overload clutch 2 with a hydraulic machine 2a, which is in particular a hydraulic pump. The hydraulic machine 2a is designed, for example, as a hydraulic machine with an adjustable displacement volume.The hydraulic overload clutch 2 further comprises a pressure relief valve 2b, which fluidly connects a suction side of the hydraulic machine 2a with a pressure side of the hydraulic machine 2a. The drive shaft 2c of the hydraulic machine 2a engages with the second track of the ring gear 3a.

[0029] The hydraulic machine 2a is arranged such that the rotational axis of the drive shaft 2c of the hydraulic machine 2a is located within the diameter of the ring gear 3a. Such an arrangement allows the size of the superposition gear to be reduced in the radial direction. For the engagement of the drive shaft 2c of the hydraulic machine 2a with the ring gear 3a, the drive shaft 2c has, for example, a gear ring at its end, which can be designed in particular as a pinion, which engages with the teeth of the second track of the ring gear 3a.

[0030] The pressure relief valve 2b can be used to prevent an overload on the drive machine 1c if the machine connected to the transmission output 1b is blocked. If the transmission output 1b comes to a standstill due to the blockage of the driven machine coupled to the transmission output 1b, for example a shredder roller, but the drive machine 1c continues to generate power or continues to rotate due to the inertia of the components of the drive machine 1c and wants to generate rotation of the sun gear 3b, the planet gears 3c and the ring gear 3a via the transmission input 1a, pressure builds up in the hydrostatic power branch 2 because the stationary planet carrier 3d transmits the entire torque to the ring gear 3a and via the drive shaft 2c to the hydraulic machine 2a.If the pressure exceeds the maximum permissible pressure set in the pressure relief valve 2b, the pressure relief valve 2b opens and connects the pressure side of the hydraulic machine 2a with the suction side of the hydraulic machine 2a. This allows the hydraulic fluid to flow freely and the hydraulic machine 2a can rotate. As a result, the torque generated by the drive motor 1c is reduced via the hydraulic overload clutch 2, preventing the drive motor 1c from sustaining damage if the transmission output 1b is blocked. The speed of the ring gear 3a, and thus the ratio of the first epicyclic gear stage 3, can be variably adjusted using the maximum permissible pressure of the pressure relief valve 2b and / or the displacement volume of the hydraulic machine 2a.

[0031] The hydraulic machine 2a can further comprise, in particular, a speed sensor that measures a speed of the hydraulic machine 2a. As previously explained, the pressure relief valve 2b opens in the event of an overload, and the hydraulic machine 2a rotates. If the speed of the hydraulic machine 2a measured by the speed sensor thus exceeds a predetermined speed value, here, for example, zero, the drive machine 1c is stopped because a blockage exists in the machine coupled to the transmission output 1c. This can prevent damage to the drive machine 1c and the superposition gear 1.

[0032] Figure 2 shows a transmission diagram of an embodiment of the superposition gear 1 with two hydraulic overload clutches 2. The same reference numerals denote the same components as in Figure 1. With regard to these components, a further explanation is omitted and explicit reference is made to the explanations for Figure 1.

[0033] In contrast to Figure 1, the superposition gear 1 has two hydraulic overload clutches 2, each with a hydraulic machine 2a. Each hydraulic machine 2a is assigned a pressure relief valve 2b that connects the suction and pressure sides of the hydraulic machine 2a. Furthermore, each hydraulic machine 2a meshes with the ring gear 3a via a drive shaft 2c. The hydraulic machines 2a can be hydraulic machines with a fixed or adjustable displacement volume.

[0034] The hydraulic machines 2a are arranged, in particular, evenly distributed on the ring gear 3a. The number of hydraulic overload clutches 2, and thus of hydraulic machines 2a, is not limited to two, but can also be three, four, or more. By using multiple hydraulic machines 2a, particularly evenly distributed along the circumference of the ring gear 3a, the ring gear 3a can be loaded more symmetrically with respect to the transverse forces resulting from the engagements, which enables a simplified, less complex, and more cost-effective bearing arrangement for the ring gear 3a.

[0035] Furthermore, one or both or all of the hydraulic machines 2a may have a speed sensor that fulfills the function already described above.

Claims

Claims 1. Superposition gear (1), in particular for a grinder, comprising: a mechanical power branch comprising a gear input (1a) which can be coupled to a drive machine (1c), a gear output (1b) which can be coupled to a driven machine, in particular to the grinder, and at least one epicyclic gear stage (3, 4, 5) via which the gear input (1a) is in a geared rotary connection with the gear output (1b) or can at least be brought into this connection, wherein a wheel (5a) of the epicyclic gear stage (3, 4, 5) is held by one or more hydraulic overload clutches (2), wherein one or each of the plurality of hydraulic overload clutches (2) has a hydraulic machine (2a) whose drive shaft (2c) is in direct or indirect engagement with the wheel (3a), and a pressure relief valve (2b) which fluidically connects a pressure side of the hydraulic machine (2a) to a suction side of the hydraulic machine (2a).

2. Superposition gear (1) according to claim 1, wherein at least one hydraulic machine (2a) of the one or more hydraulic overload clutches (2) has a speed sensor which determines the speed of the hydraulic machine (2a).

3. Superposition gear (1) according to one of the preceding claims, wherein the superposition gear (1) has several, in particular two or three, hydraulic overload clutches (2).

4. Superposition gear (1) according to the preceding claim, wherein the axes of rotation and / or the engagements of each of the plurality of drive shafts (2c) are arranged uniformly distributed along a circumference of the wheel (3a).

5. Superposition gear (1) according to one of the preceding claims, wherein the axis of rotation of the one or each of the plurality of drive shafts (2c) is arranged within a diameter of the wheel (3a).

6. Superposition gearing (1) according to one of the preceding claims, wherein the one or each of the drive shafts (2c) is in direct or indirect engagement with the wheel (3a) on an inner circumference thereof.

7. Superposition gearing (1) according to the preceding claim, wherein the one or each of the plurality of drive shafts (2c) has external teeth, and the engagement is formed by the external teeth and an internal toothing of the wheel (3a).

8. Superposition gear (1) according to one of the preceding claims, wherein the one or at least one of the hydraulic machines (2a) has an adjustable displacement volume.

9. Superposition gear (1) according to one of the preceding claims, wherein the mechanical power branch has several, in particular two or three, epicyclic gear stages (3, 4, 5).

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