Clutch arrangement for torque transmission between two shafts

Abstract

The invention relates to a clutch arrangement for torque transmission between two shafts (3, 4), characterised in that for torque transmission, two freewheel clutches (1, 2) with mutually opposite torque transmission directions (A, B) are each arranged in the force flow between the shafts (3, 4) and the torque transmission in the respective torque transmission direction (A, B) is limited to a predefined maximally transmittable torque (Mmax).

Description

[0001] Coupling arrangement for torque transmission between two shafts

[0002] The invention relates to a coupling arrangement for transmitting torque between two shafts.

[0003] From EP 1 106 854 B1 an overload clutch between a drive shaft and an output shaft is known, wherein a drive gear is provided with respect to the drive side and an overload protection part having integrated spring elements is arranged axially downstream of the drive gear and interacts with a toothed element firmly connected to the output shaft.

[0004] The invention is therefore based on the object of proposing a clutch arrangement of the aforementioned type which is structurally simple, cost-effective and space-saving and avoids overloading during torque transmission.

[0005] The problem is solved by the features of claim 1. Further advantageous and claimed embodiments emerge from the respective subclaims, the description, and the drawings.

[0006] Thus, a clutch arrangement for torque transmission between two shafts is proposed, wherein for torque transmission two freewheel clutches with opposing torque transmission directions are arranged in the power flow between the shafts and in the respective torque transmission direction the torque transmission is limited to a predetermined maximum transmittable torque.

[0007] The arrangement with two counter-rotating one-way clutches allows for a structurally simple yet space-saving design for torque transmission between the shafts in both directions of rotation. Overloading can be reliably avoided in both directions of rotation by limiting the maximum transmittable torque by the respective one-way clutch. Furthermore, the one-way clutches are easy to manufacture cost-effectively from mass-produced components. The proposed clutch arrangement can be used, for example, in transmission applications to reliably absorb short-term torque peaks, such as those that occur in vehicles when moving over uneven ground, and to prevent damage to the one-way clutches and the transmission. At the same time, trouble-free operation is enabled.

[0008] To limit the maximum transmittable torque, each overrunning clutch can preferably be switched to slipping mode upon reaching the maximum transmittable torque in the respective torque transmission direction. This allows the torque transmission to be reliably limited in a particularly simple manner in the proposed clutch arrangement.

[0009] In a preferred particularly space-saving arrangement, the overrunning clutches are arranged coaxially one behind the other and each coaxially to the shafts between the inner diameter of a first shaft, which is designed at least in sections as a hollow shaft, and the outer diameter of a second shaft.

[0010] An embodiment of the invention which is further simplified in structure, saves further installation space and is lightweight, provides that the overrunning clutches are each connected to the inner diameter of a hollow shaft section of the first shaft in a rotationally fixed manner by the outer diameter of an outer ring and are movably arranged in a clamping gap formed coaxially between the respective outer ring and the outer diameter of the second shaft.

[0011] Alternatively, in a further particularly advantageous manner, the freewheel clutches can each be connected to the outer diameter of the second shaft in a rotationally fixed manner by the inner diameter of an inner ring and can be movably arranged in a clamping gap formed coaxially between the respective inner ring and the inner diameter of the hollow shaft section of the first shaft.

[0012] Preferably, the clamping bodies are movably guided on clamping ramps formed in the respective clamping gap and, in the event of an overload, can be moved from a working area for force transmission in the torque transmission direction into an overload area on the clamping ramps. The overload area is designed such that the clamping bodies slide on the respective clamping ramp and the force transmission is limited to a maximum transmittable torque.

[0013] The overrunning clutches are preferably of identical design. Alternatively, they can also be designed differently, for example, with regard to the design of the clamping ramps, in order to be able to set different limits on the transmittable torque, particularly in different directions of rotation.

[0014] In another particularly preferred embodiment of the invention, clamping rollers are provided as clamping bodies. Consequently, a linear contact can be achieved at the clamping contact between the clamping ramps and the clamping bodies, and between these and the second shaft, thereby reducing the load on the clamping contact during operation. Alternatively, the use of balls as clamping bodies is also conceivable.

[0015] In an advantageous development of the invention, the outer rings of the overrunning clutches are each designed as a sheet metal sleeve. This allows them to be manufactured particularly lightweight and, at the same time, particularly easily and cost-effectively using sheet metal processing methods, particularly by punching and deep drawing. Preferably, the clamping ramps on the inner diameter of the respective outer ring are manufactured using a non-cutting deep drawing process. This allows the outer rings to be manufactured in a single step with the clamping ramps.

[0016] In an alternative embodiment, the clamping ramps on the outer diameter of a respective inner ring of the overrunning clutches can preferably be formed in sheet metal.

[0017] It is also advantageous if the outer rings of the one-way clutches are each designed with a radially inwardly projecting rim at their axial ends to provide axial guidance for the clamping bodies. The respective rim can be easily manufactured from sheet metal by deep drawing or collar drawing. A further development of the invention provides for the second shaft to be offset radially inward at the end with a stub shaft and to engage, in a radially mounted manner, in a second hollow shaft section that is offset radially inward on the first shaft. In a structurally simple and cost-effective manner, radially mounted support for the shafts can thus be achieved in a very compact, space-saving arrangement. This means that the one-way clutches can be arranged without radial load, reliably preventing damage caused by impacts during operation.

[0018] Preferably, a rolling bearing is provided as the radial bearing between the shaft stub and the second hollow shaft section. However, a plain bearing is also conceivable, particularly by means of a finely ground transition or clearance fit between the shaft stub and the second hollow shaft section.

[0019] Preferably, the rolling bearing is connected to a bearing outer ring with the outer diameter in a rotationally fixed manner to the inner diameter of the second hollow shaft section.

[0020] The rolling bearing is preferably designed as a needle bearing, which has a low radial height and a high load capacity. Preferably, needle rollers are guided in a rolling manner on the inner diameter of the bearing outer ring and on the outer diameter of the shaft stub.

[0021] Further claimed features of the invention will become apparent from the following description and the drawings, which further explain the present invention. They show:

[0022] Figure 1 shows a coupling arrangement according to the invention for transmitting torque between two shafts in a cross section,

[0023] Figure 2 is a side view, partially sectioned along the section line A - A, of a first freewheel clutch of the clutch arrangement,

[0024] Figure 3 is an enlarged detail of Figure 2, Figure 4 is a partially sectioned side view of a second freewheel clutch of the clutch arrangement along the section line B - B,

[0025] Figure 5 shows an enlarged section of Figure 4,

[0026] The figures show various views of a coupling arrangement according to the invention for transmitting torque between two shafts by way of example.

[0027] The clutch arrangement shown in Figure 1 comprises two separate, preferably identically constructed, overrunning clutches 1, 2, which are arranged coaxially one behind the other in the power flow between two parallel shafts 3, 4. The overrunning clutches 1, 2 are provided with opposing

[0028] Torque transmission direction A, B, as shown in Figures 3 and 5 and can only transmit torque in one of the respective directions of rotation A, B, in the other direction of rotation A, B they run idle. The opposing arrangement of the one-way clutches 1, 2 ensures that torque can be transmitted in both directions of rotation A, B of the shafts 3, 4 and that only one one-way clutch 1, 2 is engaged at a time, while the other is load-free.

[0029] The shafts 3, 4 are arranged coaxially one behind the other. A first shaft 3, with a first hollow shaft section 8 widened at its end, encompasses the free end of the second shaft 4. The first shaft 3 forms, for example, an input shaft, and the second shaft 4 an output shaft.

[0030] The one-way clutches 1, 2 are each arranged radially between the inner diameter of the first hollow shaft section 8 of the first shaft 3 and the outer diameter of the second shaft 4. A first one-way clutch 1 is connected to the outer diameter of an outer ring 6, 7 in a rotationally fixed manner to the inner diameter of the first hollow shaft section 8. The one-way clutches 1, 2 are preferably pressed into the outer ring 6, 7 directly behind one another. They are arranged coaxially to the second shaft 4, enclosing the latter at its outer diameter. The axis of rotation 5 of the shafts 3, 4 simultaneously forms the respective center axis of the one-way clutches 1, 2.

[0031] Clamping bodies 10 designed as clamping rollers are arranged in a radial clamping gap 9 formed coaxially between the inner diameter of the respective outer ring 6, 7 and the outer diameter of the second shaft 4 (Figures 2 to 5). These are each guided in a rolling manner on clamping ramps 11 formed in the respective clamping gap 9 and on the outer diameter of the second shaft 4. Thus, a clamping body 10 is guided on each clamping ramp 11. The clamping ramps 11 are each formed on the inner diameter of the outer ring 6, 7.

[0032] The overrunning clutches 1, 2 each have a working or clamping area 13 for transmitting power and torque in the respective direction of rotation A, B and an overload area 14 on the clamping ramps 11. The working or clamping area 13 is delimited in the respective torque transmission direction A, B by an arcuate section 15 and the overload area 14 is delimited opposite to the respective torque transmission direction A, B by a kink 16. Opposite to the respective torque transmission direction A, B, the clamping ramps 11 rise slightly towards the overload area 14, so that the radial clamping gap 9 formed to the second shaft 4 tapers. The course of the clamping ramps 11 at the kink 16 in the contact or starting point of the clamping bodies 10 in the respective excess load area 14 is formed by a tangent to the outer diameter of the clamping bodies 10.

[0033] For each clamping body 4, a spring element 17 is arranged in the clamping gap, which acts as a compression spring and preloads each clamping body 10 against the respective torque transmission direction A, B of the overrunning clutches 1, 2.

[0034] If the respective one-way clutch 1, 2 is at a standstill or in idle operation, i.e. no torque is applied in the respective torque transmission direction A, B, the respective clamping bodies 10 are rolled into an initial position in the working or clamping area 13 of the clamping ramps 11 in the area of ​​the section 15. The clamping bodies 10 are clamped in the clamping gap 9, so that at the clamping contact of the clamping bodies 10 with the clamping ramps 11 under static friction conditions, a force can be frictionally transmitted from the outer ring 6, 7 of the respective one-way clutch 1, 2 via the clamping bodies 4 rolling on the outer diameter of the second shaft 4 to the second shaft 4 or vice versa from this to the outer ring 6, 7.

[0035] If a torque is applied in the respective torque transmission direction A, B, a normal force is generated at the clamping contact of the clamping bodies 10 with the clamping ramps 11, expanding the outer ring 6, 7. This causes the first shaft 3 to deflect accordingly at the first hollow shaft section 8. This causes the clamping gap 9 to widen, and the clamping bodies 10 move along the clamping ramps 11 toward the overload area 14.

[0036] If the overload on the respective one-way clutch 1, 2 is reached with a predetermined maximum transmittable torque Mmax, the clamping bodies 4 run up or onto the second kink 16 on the overload area 14 as shown in Figures 3 and 5. The clamping conditions at the clamping contact of the clamping bodies 10 change with the clamping ramps 11. The approach or clamping angle a at the clamping contact increases in such a way that tan a > p, where p is the static friction coefficient of the friction partners at the clamping contact. Under this clamping condition, the frictional clamping at the clamping contact is released, so that the clamping bodies 10 slip on the clamping ramps. Consequently, the torque build-up on the respective one-way clutch 1, 2 is stopped and the torque transmission is limited to the maximum transmittable torque Mmax.

[0037] The setting or clamping angle a at the clamping contact is formed between a force F to be transmitted and the normal N at the clamping contact as shown as an example in Figure 3.

[0038] The torque limitation allows a peak load to be automatically absorbed and continued operation below the overload level is possible without disrupting continued operation, in particular due to a drop in torque transmission to zero. The load limitation enables, in particular, a smaller design of the one-way clutches 1, 2. If the load on the respective one-way clutch 1, 2 is reduced again during operation, the respective clamping bodies 10 move back into the working or clamping area 13 on the respective clamping ramps 11 and torque transmission is resumed. In the working or clamping area 13, the clamping angle a at the clamping contact decreases again so that tan a < p and static frictional engagement is achieved at the clamping contact. As a result, a force can again be transmitted at the clamping contact.

[0039] During operation, by applying a torque to the first shaft 3, one of the overrunning clutches 1, 2 will absorb the torque in the respective torque transmission direction A, B. The torque is transmitted to the second shaft 3 via the respective outer ring 6, 7 and the clamping bodies 10. The other overrunning clutch 1, 2 is in idle and load-free mode. In a changed torque transmission direction A, B, the torque is transmitted via the latter, while the first-mentioned overrunning clutch 1, 2 is in idle and load-free mode.

[0040] In this way, torque transmission is enabled in both directions of rotation A and B by the opposing overrunning clutches 1, 2, while simultaneously achieving a corresponding torque limitation as described above. Torque transmission is also possible in the opposite direction, from the second shaft 4 via the overrunning clutches 1, 2 to the first shaft 3.

[0041] According to Figure 1, the outer rings 6, 7 of the overrunning clutches 1, 2 are each formed at the axial ends with a radially inwardly projecting annular peripheral rim 18, 19 on which the clamping bodies 4 are axially guided.

[0042] The outer rings 6, 7 are preferably each designed as a sleeve, which is preferably made from sheet metal by punching and deep-drawing without machining. The clamping ramps 11 are preferably made on the inner diameter of the respective outer ring by deep-drawing without machining. The rims 18, 19 can simply be produced as collars by deep-drawing or collar-drawing. The second shaft 4 has a shaft stub 20 that is offset radially inward at the coupling-side end and engages with this in a radially mounted second hollow shaft section 21 that is offset radially inward on the first shaft 3. A rolling bearing 22 with an outer bearing ring 23 is provided as the radial bearing, the outer diameter of which is connected in a rotationally fixed manner to the inner diameter of the second hollow shaft section 21.The rolling bearing 22 is preferably designed as a needle bearing with needle rollers 24, which are guided in a rolling manner on the inner diameter of the bearing outer ring 23 and on the outer diameter of the shaft stub 20. The rolling bearing 22 supports radial loads between the shafts, so that the overrunning clutches 1, 2 are arranged largely free of radial loads.

[0043] List of reference symbols

[0044] 1 Overrunning clutch 2 Overrunning clutch

[0045] 3 Wave

[0046] 4 Shaft 5 Rotation axis, central axis

[0047] 6 Outer ring 7 Outer ring

[0048] 8 first hollow shaft section 9 clamping gap

[0049] 10 Clamping body, clamping roller 11 Clamping ramp

[0050] 13 Working area for force transmission, clamping area 14 Overload area 15 Section 16 Bend 17 Spring element, compression spring 18 Board, collar

[0051] 19 Board, collar 20 Shaft stub 21 second hollow shaft section

[0052] 22 Rolling bearing, needle bearing 23 Bearing outer ring 24 Needle rollers A Torque transmission direction, direction of rotation B Torque transmission direction, direction of rotation a Clamping angle

[0053] F Force N Normal

Claims

Patent claims 1 . Coupling arrangement for torque transmission between two shafts (3, 4), characterized in that for torque transmission two freewheel clutches (1, 2) with mutually opposite Torque transmission direction (A, B) are each arranged in the power flow between the shafts (3, 4) and the torque transmission in the respective torque transmission direction (A, B) is limited to a predetermined maximum transmittable torque (Mmax).

2. Clutch arrangement according to claim 1, characterized in that in order to limit the maximum transmittable torque (Mmax), each freewheel clutch (1, 2) can be transferred into a slipping operation when the maximum transmittable torque (Mmax) is reached in the respective torque transmission direction (A, B).

3. Clutch arrangement according to one of claims 1 or 2, characterized in that the freewheel clutches (1, 2) are arranged coaxially one behind the other and each coaxially to the shafts (3, 4) between the inner diameter of a first shaft (3), which is designed at least in sections as a hollow shaft, and the outer diameter of a second shaft (4).

4. Clutch arrangement according to one of claims 1 to 3, characterized in that the freewheel clutches (1, 2) are each connected to the inner diameter of a hollow shaft section (8) of the first shaft (4) in a rotationally fixed manner by the outer diameter of an outer ring (6, 7) and are movably arranged in a clamping gap (9) formed coaxially between the respective outer ring (6, 7) and the outer diameter of the second shaft (4).

5. Coupling arrangement according to claim 4, characterized in that the clamping bodies (10) are movably guided on clamping ramps (11) formed in the respective clamping gap (9) and, in the event of overload, are each moved from a working area (13) for force transmission into an overload area (14) on the clamping ramps (11). are movable, wherein the overload area (14) is designed such that the clamping bodies (10) each slide on the respective clamping ramp (11) and the force transmission is limited to a maximum transmittable torque (Mmax).

6. Coupling arrangement according to one of claims 4 or 5, characterized in that clamping rollers are provided as clamping bodies (10).

7. Clutch arrangement according to one of claims 3 to 5, characterized in that the outer rings (6, 7) of the freewheel clutches (1, 2) are each designed as a sleeve made of sheet metal.

8. Clutch arrangement according to one of claims 4 to 6, characterized in that the outer rings (6, 7) of the freewheel clutches (1, 2) are each designed at the axial ends with a radially inwardly projecting rim (18, 19) for axially guiding the clamping bodies (10).

9. Coupling arrangement according to one of claims 1 to 8, characterized in that at the end of the second shaft (4) a shaft stub (20) is offset radially inwards and engages in a radially mounted second hollow shaft section (21) offset radially inwards on the first shaft (3).

10. Coupling arrangement according to claim 9, characterized in that a needle bearing (22) with a bearing outer ring (23) is provided for radial mounting, which is connected with the outer diameter in a rotationally fixed manner to the inner diameter of the second hollow shaft section (21), and needle rollers (24) are guided in a rolling manner on the one hand on the inner diameter of the bearing outer ring (23) and on the other hand on the outer diameter of the shaft stub (20).

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