HYDRODYNAMIC FRICTION CLUTCH

Abstract

A hydrodynamic friction clutch may include a rotatably mounted shaft, a drive disc non-rotatably fixed on the shaft, and an output body rotatably fixed on the shaft. The drive disc may include a radially extending annular transmission region for receiving a viscous fluid and via which the drive disc may be couplable to the output body for transmitting a torque, and an annular segment-shaped storage chamber for receiving the viscous fluid. The transmission region may be fluidically connected to the storage chamber via an inlet path and a drainage path. In the inlet path, a closable valve opening for controlling the quantity of the viscous fluid in the transmission region may be provided. The inlet path may include an annular segment-shaped communication passage, which may fluidically connect the storage chamber to the valve opening. The drainage path may fluidically connect to the inlet path at the valve opening.

Claims

1. A hydrodynamic friction clutch, comprising: a rotatably mounted shaft; a drive disc non-rotatably fixed on the shaft; and an output body rotatably fixed on the shaft; wherein the drive disc includes a radially extending annular transmission region for receiving a viscous fluid and via which the drive disc is couplable to the output body for transmitting a torque; wherein the drive disc includes an annular segment-shaped storage chamber for receiving the viscous fluid; wherein the transmission region is fluidically connected to the storage chamber via an inlet path and via a drainage path; wherein, in the inlet path, a closable valve opening for controlling the quantity of the viscous fluid in the transmission region is provided; wherein the inlet path includes an annular segment-shaped communication passage, which fluidically connects the storage chamber to the valve opening; and wherein the drainage path fluidically connects to the inlet path at the valve opening.

2. The hydrodynamic friction clutch according to claim 1, wherein: in an engaged mode, the valve opening is open, wherein the viscous fluid is flowable from the transmission region through the drainage path to the valve opening and further through the inlet path back into the transmission region, and wherein the viscous fluid is flowable out of the storage chamber through the inlet path into the transmission region; and in a disengaged mode, the valve opening is closed, wherein the viscous fluid is flowable through the drainage path out of the transmission region into the communication passage and into the storage chamber and is not flowable out of the storage chamber.

3. The hydrodynamic friction clutch according to claim 1, wherein: the drainage path includes a resistance body in the drive disc, which is formed on the transmission region located radially outside; the drainage path includes a drainage bore in the drive disc, which fluidically connects the resistance body to an outlet opening in the drive disc; and the drainage path includes at least one radially orientated pumping passage in the drive disc, which fluidically connects the outlet opening and the valve opening.

4. The hydrodynamic friction clutch according to claim 3, wherein, in the drainage path, the viscous fluid is consecutively flowable through the resistance body, the drainage bore, the outlet opening, and the at least one pumping passage in an engaged mode and in a disengaged mode.

5. The hydrodynamic friction clutch according to claim 1, wherein: the drainage path includes a resistance body in the output body, which is arranged on the transmission region located radially outside; the drainage path includes a drainage bore in the output body, which fluidically connects the resistance body to another drainage bore in the output body; the drainage path includes an annular segment-shaped collection groove in the drive disc, into which the outlet opening leads; and the drainage path includes at least one passage path in the drive disc, which fluidically connects the collection groove and the valve opening.

6. The hydrodynamic friction clutch according to claim 5, wherein, in the drainage path, the viscous fluid, in an engaged mode and in a disengaged mode, is consecutively flowable through the resistance body, the drainage bore, the outlet opening, the collection groove, and the passage path.

7. The hydrodynamic friction clutch according to claim 1, wherein the inlet path includes an inlet bore which connects the valve opening to a zone of the transmission region located radially inside.

8. The hydrodynamic friction clutch according to claim 7, wherein: in an engaged mode in the inlet path, the viscous fluid is consecutively flowable through the storage chamber, the communication passage, the valve opening, and the inlet bore; and in a disengaged mode in the inlet path, the viscous fluid is not flowable through the inlet bore and the valve opening, and is consecutively flowable through the communication passage and the storage chamber.

9. The hydrodynamic friction clutch according to claim 1, wherein: the annular segment-shaped storage chamber has an outer radius deviating in the circumferential direction, which from a middle outlet region continuously decreases towards lateral end regions; and the communication passage fluidically connects to the storage chamber in the outlet region.

10. The hydrodynamic friction clutch according to claim 9, wherein an annular segment-shaped ventilation passage connects at least at one of the end regions of the storage chamber.

11. The hydrodynamic friction clutch according to claim 1, wherein the annular segment-shaped communication passage extends in the circumferential direction by an arc angle between 160 and 200.

12. The hydrodynamic friction clutch according to claim 1, wherein at least one axial outer wall of the storage chamber is inclined towards the shaft from the outside to the inside.

13. The hydrodynamic friction clutch according to claim 5, wherein the collection groove is eccentric.

14. A hydrodynamic friction clutch, comprising: a rotatably mounted shaft; a drive disc non-rotatably fixed on the shaft; and an output body rotatably fixed on the shaft; wherein the drive disc includes a radially extending annular transmission region for receiving a viscous fluid and via which the drive disc is couplable to the output body for transmitting a torque; wherein the drive disc includes an annular segment-shaped storage chamber for receiving the viscous fluid; wherein the transmission region is fluidically connected to the storage chamber via an inlet path and via a drainage path; wherein, in the inlet path, a closable valve opening for controlling the quantity of the viscous fluid in the transmission region is provided; wherein the inlet path includes an annular segment-shaped communication passage, which fluidically connects the storage chamber to the valve opening; wherein the drainage path fluidically connects to the inlet path at the valve opening; wherein, in an engaged mode, the valve opening is open, wherein the viscous fluid is flowable from the transmission region through the drainage path to the valve opening and further through the inlet path back into the transmission region, and wherein the viscous fluid is flowable out of the storage chamber through the inlet path into the transmission region; and in a disengaged mode, the valve opening is closed, wherein the viscous fluid is flowable through the drainage path out of the transmission region into the communication passage and into the storage chamber and is not flowable out of the storage chamber.

15. The hydrodynamic friction clutch according to claim 14, wherein: the drainage path includes a resistance body in the drive disc, which is formed on the transmission region located radially outside; the drainage path includes a drainage bore in the drive disc, which fluidically connects the resistance body to an outlet opening in the drive disc; and the drainage path includes at least one radially orientated pumping passage in the drive disc, which fluidically connects the outlet opening and the valve opening.

16. The hydrodynamic friction clutch according to claim 15, wherein, in the drainage path, the viscous fluid is consecutively flowable through the resistance body, the drainage bore, the outlet opening, and the at least one pumping passage in the engaged mode and in the disengaged mode.

17. The hydrodynamic friction clutch according to claim 14, wherein: the drainage path includes a resistance body in the output body, which is arranged on the transmission region located radially outside; the drainage path includes a drainage bore in the output body, which fluidically connects the resistance body to another drainage bore in the output body; the drainage path includes an annular segment-shaped collection groove in the drive disc, into which the outlet opening leads; and the drainage path includes at least one passage path in the drive disc, which fluidically connects the collection groove and the valve opening.

18. The hydrodynamic friction clutch according to claim 17, wherein, in the drainage path, the viscous fluid, in the engaged mode and in the disengaged mode, is consecutively flowable through the resistance body, the drainage bore, the outlet opening, the collection groove, and the passage path.

19. The hydrodynamic friction clutch according to claim 14, wherein the inlet path includes an inlet bore which connects the valve opening to a zone of the transmission region located radially inside.

20. The hydrodynamic friction clutch according to claim 19, wherein: in the engaged mode in the inlet path, the viscous fluid is consecutively flowable through the storage chamber, the communication passage, the valve opening, and the inlet bore; and in the disengaged mode in the inlet path, the viscous fluid is not flowable through the inlet bore and the valve opening, and is consecutively flowable through the communication passage and the storage chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] There it shows in each case schematically

[0021] FIG. 1 a sectional view of a hydrodynamic friction clutch according to the invention in a first embodiment;

[0022] FIG. 2 a view of a drive disc in the hydrodynamic friction clutch in the first embodiment;

[0023] FIG. 3 a hydraulic diagram of the hydrodynamic friction clutch in the first embodiment in a engaged mode;

[0024] FIG. 4 a hydraulic diagram of the hydrodynamic friction clutch in the first embodiment in a disengaged mode;

[0025] FIG. 5 a sectional view of a hydrodynamic friction clutch according to the invention in a second embodiment;

[0026] FIGS. 6 and 7 views of a drive disc in the hydrodynamic friction clutch in the second embodiment;

[0027] FIG. 8 a sectional view of a drive disc in the hydrodynamic friction clutch in the second embodiment;

[0028] FIG. 9 a hydraulic diagram of the hydrodynamic friction clutch in the second embodiment in a engaged mode;

[0029] FIG. 10a hydraulic diagram of the hydrodynamic friction clutch in the second embodiment in a disengaged mode.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a sectional view of a hydrodynamic friction clutch 1 according to the invention in a first embodiment. The hydrodynamic friction clutch 1 comprises a rotatably mounted shaft 2, on which a drive disc 3 is non-rotatably fixed and a drive body 4in this exemplary embodiment a motor vehicle fan 5is rotatably fixed. In FIG. 2, a view of the drive disc 3 is shown. Here, the drive disc 3 has a radially extending annular transmission region 6 for receiving a viscous fluid, via which the drive disc 3 is couplable to the drive body 4 for transmitting a torque. Furthermore, the drive disc 3 comprises an annular segment-shaped storage chamber 7 for receiving the viscous fluid, wherein the transmission region 6 is fluidically connected to the storage chamber 7 via an inlet path 8 and a drainage path 9.

[0031] The drainage path 9 of the hydrodynamic friction clutch 1 in the first embodiment is arranged on the primary side or drive side and comprises a resistance body 10a, a drainage bore 11a, an outlet opening 12a and a radially orientated pumping passage 13. The resistance body 10a is formed in the drive disc 3 located radially outside on the transmission region 6 and is fluidically connected to the outlet opening 12a via the drainage bore 11a in the drive disc 3. The pumping passage 13 in the drive disc 3 fluidically connects the outlet opening 12a to the inlet path 8. The inlet path 8 comprises the storage chamber 7 and an annular segment-shaped communication passage 14, which fluidically connects the storage chamber 7 to a closable valve opening 15. The drainage path 9 also leads into the inlet path 8 at the valve opening 15. Furthermore, the inlet path 8 comprises an inlet bore 16 which connects the valve opening 15 to a zone of the transmission region 6 located radially inside.

[0032] The hydrodynamic friction clutch 1 can be operated in a engaged mode and in a disengaged mode, as is explained in more detail in the following by way of FIG. 3 and FIG. 4. In the engaged mode, the viscous fluid, because of the centrifugal force acting on the fluid, consecutively flows in the inlet path 8 through the storage chamber 7, the communication passage 14, the valve opening 15 and the inlet bore 16. The fluid flows out of the storage chamber 7 into the transmission region 6. At a high rotational speed of the drive disc 3 and with a large radius difference between the storage chamber 7 and the valve opening 15, the storage chamber 7 can be emptied particularly quickly. In the drainage path 9, the viscous fluid consecutively flows through the resistance body 10a, the drainage bore 11a, the outlet opening 12a and the pumping passage 13. In the process, the viscous fluid flows out of the transmission region (6) because of a remaining slip via the drainage path 9 to the opened valve opening 15 of the inlet path 8 and because of a minor throttling of the valve opening 15, back into the transmission region 6. By way of this, the fluid from the storage chamber 7 is almost completely conveyed into the transmission region 6.

[0033] In the disengaged mode, the valve opening 15 is closed so that in the inlet path 8 the inlet bore 16 and the valve opening 15 are not flowed through. In the drainage path 9, the viscous fluid continues to consecutively flow through the resistance body 10a, the drainage bore 11a, the outlet opening 12a and the pumping passage 13. Since however the valve opening 15 is closed, the fluid after the pumping passage 13 flows in the inlet path 8 into the communication passage 14 and further into the storage chamber 7. Because of this, the fluid, in the drainage mode, can be conveyed almost completely out of the transmission space 6 into the storage chamber 7. In the hydrodynamic friction clutch 1, the storage chamber 7 and the transmission region 6 can be advantageously emptied completely and quickly in contrast with conventional hydrodynamic friction clutches, as a result of which the dynamic regulation of the hydrodynamic friction clutch 1 is improved and a quicker engagement and disengagement of the output body 4 can be achieved.

[0034] In addition, the annular segment-shaped storage chamber 7 has an outer radius that deviates in the circumferential direction, which from a middle outlet region 17 becomes continuously smaller towards lateral end regions 18. The communication passage 14 fluidically connects to the storage chamber 7 in the outlet region 17. When the drive disc 3 is rotated, the viscous fluid is thereby forced out of the end regions 18 to the outlet region 17 so that the emptying of the storage chamber 7 is supported in the engaged mode. In addition, an outer wall 20 of the storage chamber 7 is inclined towards the shaft 2 so that a drainage of the fluid to the communication passage 14 is supported. By way of the annular segment-shaped ventilation passages 19 linking up to the end regions 18, the pressure differential during the emptying of the storage chamber 7 can be additionally equalised.

[0035] Furthermore, the communication passage 14 which extends by 180 in the circumferential direction constitutes an obstacle for the viscous fluid with the non-driven hydrodynamic friction clutch 1 in the friction clutch 1 according to the invention, so that the viscous fluid cannot enter the transmission region 6 even with an unfavourable angle of rotation position of the drive disc 3.

[0036] In an unfavourable angle of rotation position of the storage chamber 7 according to FIG. 2, the outlet region 17 of the storage chamber 7 lies at the bottom and the fluid can flow out of the storage chamber 7 into the communication passage 14 under the effect of the gravitational force. Here, the valve opening 15 is twisted by 180 relative to the outlet region 17 thereby arranged at the top. Consequently the fluid cannot enter the valve opening 15 and remains in the communication passage 14. In an unfavourable angle of rotation position of the valve opening 15, the same is arranged at the bottom and the fluid can flow through the valve opening 15 into the transmission region 6. Since however the outlet region 17 of the connection space 7 lies twisted by 180 and consequently at the top, the fluid from the storage chamber 7 cannot reach the communication passage 14 and consequently not enter the valve opening 15. Because of this, the drive body 4, with the non-driven hydrodynamic friction clutch 1, remains securely decoupled from the drive disc 3 and an undesirable co-rotating of the output body 4 after a drive start of the hydrodynamic friction clutch 1 that has been disengaged for an extended period of time is advantageously prevented.

[0037] FIG. 3 and FIG. 4 show hydraulic diagrams of the hydrodynamic friction clutch 1 in the first embodiment in the engaged mode and in the disengaged mode. In the hydraulic diagram shown here, a rotating system was analogously transformed into a non-rotating system wherein the centrifugal force of the rotating system was figuratively replaced with the gravitational force. In FIG. 3, the hydrodynamic friction clutch 1 is in the engaged mode and the fluid is nearly completely conveyed out of the storage chamber 7 into the transmission region 6. In the process, the storage chamber 7, the communication channel 14, the valve opening 15 and the inlet bore 16 are consecutively flowed through in the inlet path 8. The drainage path 9 links up at the opened valve opening 15 with the inlet path 8, so that the fluid from the transmission region 6 flows back into the transmission region 6. The storage chamber 7, furthermore, is configured funnel-shaped through the deviating outer radius, so that the emptying of the storage chamber 7 is additionally supported. In FIG. 4, the hydrodynamic friction clutch 1 is in the disengaged mode and the fluid is nearly completely conveyed into the storage chamber 7. Here, the valve opening 15 is closed so that in the inlet path 8 the inlet bore 16 and the valve opening 15 are not flowed through. In the drainage path 9, the resistance body 10a, the drainage bore 11a, the outlet opening 12a and the pumping passage 13 continue to be consecutively flowed through. Since the valve opening 15 is closed, the fluid, after the pumping passage 13, flows in the inlet path 8 into the communication passage 14 and on into the storage chamber 7.

[0038] FIG. 5 shows a sectional view of the hydrodynamic friction clutch 1 according to the invention in a second embodiment. FIG. 6 and FIG. 7 show views and FIG. 8 shows a sectional view of the drive disc 3 of the hydrodynamic friction clutch 1 in the second embodiment. Deviating from the hydrodynamic friction clutch 1 in FIG. 1 to FIG. 4, the drainage path 9 in this case is arranged partly on the secondary side or on the drive side. Here, the drainage path 9 comprises the resistance body 10b, the drainage bore 11b and the outlet opening 12b which are formed in the output body 4 on the secondary side. Furthermore, the drainage path 9 comprises an annular segment-shaped eccentric collection groove 21 and a passage path 22, which are formed in the drive disc 3 on the primary side. The outlet opening 12b leads into the collection groove 21 which is fluidically connected to the valve opening 15 by two passages 23 of the passage path 22. The hydrodynamic friction clutch 1 in the second embodiment otherwise corresponds to the hydrodynamic friction clutch 1 in the first embodiment.

[0039] The choice of the embodiment of the hydrodynamic friction clutch 1 depends on the maximum rotational speed of the driveshaft 3. In principle it should be noted that up to approximately 4,000 revolutions per minute the first embodiment and from approximately 4,000 revolutions per minute the second embodiment are advantageous. The reason for this distinction is the difference of the stagnation pressure in the drainage path 9, which at higher rotational speeds of the drive disc 3 can no longer overcome the difference of the pressure in the inlet path 8 generated by the centrifugal force. Since the rotational speed of the drive body 4and in particular of the motor vehicle fan 5does not usually exceed 4,000 revolutions per minute, the drainage path 9 at the maximum rotational speed of the drive disc 3 above approximately 4,000 revolutions per minute can be arranged on the secondary side.

[0040] FIG. 9 and FIG. 10 show hydraulic diagrams of the hydrodynamic friction clutch 1 in the second embodiment in the engaged mode and in the disengaged mode. In the hydraulic diagrams shown here, a rotating system was analogously transformed into a non-rotating system, wherein the centrifugal force of the rotating system was figuratively replaced with the gravitational force. In FIG. 9, the hydrodynamic friction clutch 1 is in the engaged mode and the fluid is conveyed out of the storage chamber 7 into the transmission region 6. Here, the storage chamber 7, the communication passage 14, the valve opening 15 and the inlet bore 16 are consecutively flowed through in the inlet path 8. The storage chamber 7 is additionally configured funnel-like through the deviating outer radius, which additionally supports the emptying of the storage chamber 7. In the drainage path 9, the fluid flows out of the transmission region 6 via the resistance body 10b, the drainage bore 11b and the outlet opening 12b initially into the collection groove 21. From the collection groove 21, the fluid is conveyed via the passage path 22 to the valve opening 15 so that the fluid from the transmission region 6 flows back into the transmission region 6. In FIG. 10, the hydrodynamic friction clutch 1 is in the disengaged mode and the fluid is conveyed out of the transmission region 6 into the storage chamber 7. Here, the valve opening 15 is closed so that in the inlet path 8 the inlet bore 16 and the valve opening 15 are not flowed through. In the drainage path 9, the resistance body 10b, the drainage bore 11b, the outlet opening 12b, the collection groove 21 and the passage path 22 are consecutively flowed through. Since the valve opening 15 is closed, the fluid, after the passage path 22 in the inlet path 8 flows into the communication passage 14 and on into the storage chamber 7.

[0041] In summary, the dynamic regulation in the hydrodynamic friction clutch 1 according to the invention can be improved and a quicker engagement and disengagement of the output body 4 achieved. Furthermore, the output body 4 can be decoupled from the drive disc 3 in the hydrodynamic friction clutch 1 according to the invention even with an unfavourable angle of rotation position of the drive disc 3, so that a co-rotating of the output body 4 after a drive start of the hydrodynamic friction clutch 1 which has been disengaged for an extended period of time can be advantageously prevented.