WO2001076041A1

WO2001076041A1 - Combined starter, alternator and damping unit

Info

Publication number: WO2001076041A1
Application number: PCT/GB2001/001491
Authority: WO
Inventors: Anthony John Curtis
Original assignee: Ap Tmf Limited
Priority date: 2000-04-04
Filing date: 2001-04-02
Publication date: 2001-10-11
Also published as: GB0008169D0; GB2365832B; GB0128255D0; GB2365832A; AU4436301A

Abstract

Various Electro-magnetic combined Starter, Alternator and Damping units (10) (ESADS) are disclosed in which a rotor element (14) of the unit is driven from an associated engine via a torsional vibration damper (15) located radially within the rotor element (14) may be supported at two axially spaced locations (21, 17a) and the rotor may drive an associated transmission via a clutch (34) which is also located radially within the rotor. A torsional vibration damper is also disclosed which includes two groups of circumferentially acting springs (23A, 23B) which initially operate in series and at higher rotation angles operate in parallel.

Description

COMBINED STARTER, ALTERNATOR AND DAMPING UNIT

This invention relates to Electro-magnetic combined Starter, Alternator and Damping units, hereinafter referred to as being "ESAD units of the kind specified", comprising an engine driven inner rotor element and an outer stator element which, under the control of an electronic controller, can function as a starter motor for an associated engine, an alternator for generating electrical power and an electrical damper for damping torsional vibrations emanating from the associated engine. Such an ESAD unit can also be used to provide a temporary boost to the torque provided by the engine to facilitate, for example, overtaking or hill starting in vehicular applications.

It is an object of the present invention to provide an improved form of ESAD unit of the kind specified.

Thus, according to a first aspect of the present invention there is provided an ESAD unit of the kind specified in which the inner rotor element is driven from the associated engine via a torsional vibration damper located radially within the rotor element.

Such an arrangement provides a compact unit in which the torsional vibrations emanating from the associated engine are at least partially attenuated by the damper located within the rotor element.

The torsional vibration damper may comprise an input member for connection with the associated engine and an output member connected with the rotor element, the input and output members rotating relative to each other in response to torsional vibrations emitted by the engine and one or more of the following damping means operating between the input and output members to resist such relative rotation:- i) single or multi- stage circumferentially acting compression springs; <^{• "}

ii) relatively rotatable friction members biased into frictional contact;

iii) bob weight linkages (see for example the applicant's patent application No. WO96/38681 ) connecting the input and output members which provide a speed dependent damping effect;

iv) viscous dampers, and

v) Elastomeric blocks loaded in compression.

In accordance with a second aspect of the invention in an ESAD unit of the kind specified the rotor is driven from the associated engine via a torsional vibration damper located radially within the rotor element and the rotor is supported at two locations spaced axially of the rotor, one rotor support being from a non-rotatable housing of the unit and the other rotor support being via the torsional vibration damper from a crankshaft of the associated engine and/or from an input shaft of an associated transmission.

The invention also provides an ESAD unit of the kind specified in which the rotor is driven from a crankshaft of the associated engine via a torsional vibration damper located radially within the rotor element and the rotor drives an input shaft of an associated transmission via a clutch also located radially within the rotor element.

In such an arrangement the clutch may be of the pull or push type and may be actuated by, for example, an hydraulic concentric slave cylinder which surrounds the input shaft and is supported from a housing of the ESAD unit or by an hydraulic cylinder which is located outside the housing of the ESAD unit. The clutch may be of the single of multi-plate type and may use organic or cerametallic friction material. Typically in such an arrangement the output of the torsional vibration damper is connected with the rotor element and an input member of the clutch is also connected with the rotor element and supports a clutch reaction member, a clutch driven plate being clamped against the reaction member by a pressure plate under the action of a belleville spring which reacts back to the rotor element, the pressure plate being non-rotatably located relative to the reaction member.

Conveniently the reaction of the belleville spring and the non-rotatable location of the pressure plate relative to the reaction plate can be done via the input member of the clutch. For example, torque straps connected at one end to the pressure plate can be connected at their other end to the clutch input member.

An annular clutch support plate may be mounted adjacent its outer periphery on the rotor (e.g. via the clutch input member) and may be mounted at the inner periphery from the ESAD housing via one of the rotor support bearings. This bearing may be carried on a concentric slave cylinder supported from the housing.

The clutch driven plate may conveniently be connected with the transmission input shaft via a splined sleeve. This sleeve may support the output member of the torsional vibration damper.

The central portion of the driven plate of the dutch may include circumferentially acting damping springs and/or friction damping to further attenuate torsional vibrations.

The clutch may also be located axially outside the rotor element, for example, the clutch may have a reaction member located axially alongside one end of the rotor element and supported therefrom.

In accordance with a further aspect of the invention the housing of the ESAD unit may be in several parts, for example, an annular portion which is supported from the engine and which carries the stator element outside the rotor element and a disclike end cover which closes-off the annular portion and may support a clutch actuator.

The annular portion of the housing may include internal passageways for the passage of coolant therethrough.

The invention also provides a method of assembling an ESAD unit of the kind specified in which the rotor element is driven from a crankshaft of the associated engine via a torsional vibration damper located radially within the rotor element and the rotor element drives an input shaft of an associated transmission via a clutch also located radially within the rotor element, the method comprising:-

securing a first sub-assembly comprising the rotor, torsional vibration damper and clutch input and reaction member onto the engine crankshaft;

securing to the associated engine a second sub-assembly comprising an ESAD housing carrying the stator element, clutch actuator, and the remainder of the clutch (including a pressure plate) supported therefrom, and

interconnecting, via apertures in the housing, the clutch reaction member and pressure plate for co-rotation.

The invention also provides a torsional vibration damper comprising an input member for connection with an associated engine and an output member for connection with a drive-line, and a damping means acting between the input and output members to resist relative rotation of the members, the damping means comprising groups (e.g. pairs) of circumferentially acting compression springs which are arranged to operate in series to resist the relative rotation of the input and output members during an initial angle of relative rotation of the members and then, during a subsequent angle of relative rotation, act in parallel to resist further relative rotation.

Such a series/parallel spring damper produces a damping characteristic with a relatively low stiffness and large relative rotation during the initial angle of rotation when the groups of springs act in series and a step increase in stiffness and much reduced relative rotation when the groups of springs act in parallel.

Such a torsional vibration damper may be used with an ESAD unit in any of the above aspects of the invention or may be used without the presence of an ESAD unit simply as a drive-line damper. Additional damping means selected from one or more of items i) to v) itemised above may also act to resist the relative rotation of the input and output members.

The above form of series/parallel spring damper may also be incorporated into a twin mass flywheel (used with or without an ESAD unit) with the input and output members constituting the input and output masses of the flywheel. Again one or more damping means selected from items i) to v) above may also be connected between the input and output masses of the flywheel.

The present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a radial half section through an ESAD unit embodying the present invention;

Figure 2 shows an alternative form of torsional vibration damper for use with the present invention;

Figure 3 shows yet a further form or torsional vibration damper for use with the present invention;

Figure 4 shows an alternative form of ESAD housing for use with the present invention;

Figure 5 shows a further form of ESAD housing including coolant passageways for use with the present invention;

Figure 6 shows an alternative form of concentric slave clutch actuator for use with the present invention;

Figure 7 shows a push-type concentric slave clutch actuator for use with the present invention;

Figures 8 and 9 show alternative clutch arrangements in which torque straps are not used;

Figure 10 shows a modified clutch arrangement in which the driven plate includes compression type damping springs and a friction device;

Figure 11 shows an alternative form of torsional vibration damper of the series/parallel type;

Figure 12 shows diagrammatical ly the relative circumferential positioning of the springs in the damper shown in figure 11 ;

Figures 13A to 13D show the sequence of operation of the series/parallel damper of figures 11 and 12;

Figures 14 and 15 show external clutch actuators for use with pull and push-type clutches used in an ESAD unit in accordance with the present invention; Figure 16 shows a further form of ESAD unit similar to that shown in figure 1 , and

Figure 17 shows diagrammatically a further form of the damper shown in figure 11.

Referring to Figure 1 of the drawings this shows an ESAD unit 10 having a housing 11 which is secured by studs X at circumferentially spaced locations around its outer periphery to an engine block 12 of an associated engine. Supported from the inside of the housing 11 is an outer stator element 13 of the ESAD unit within which a rotor element 14 is supported at one end via a torsional vibration damper 15 from a flywheel 16 of the associated engine and at the other end from the housing 11 via a bearing 17 supported from the housing via a concentric slave clutch actuator 18.

The torsional vibration damper 15 comprises an input member 19 which is non- rotatably secured to the flywheel 16 and an output member 20 which is supported via a plain bearing 21 from a pilot boss 22a formed on crankshaft 22 to which flywheel 16 is secured. The input and output members of the damper 15 are connected for the transmission of torque from the crankshaft to the rotor element 14 via circumferentially spaced compression springs 23 which are housed in windows 24 and 25 in input member 19 and output member 20 respectively. Thus input member 19 can rotate circumferentially relative to output member 20, resulting in compression of springs 23, to damp torsional vibrations emanating from the engine to attenuate the transmission of these vibrations to the rotor element 14.

Additionally, and optionally, a friction damping device 26 acts between the input member 19 and output member 20. This device comprises an axially acting belleville spring 27 a pressure ring 28 a first friction member 29 which rotates with output member 20 and a second friction member 30 which is bonded onto or otherwise rotationally connected with input member 19.

Output member 20 of torsional vibration damper 15 is provided with an annular flange 31 which is secured to rotor element 14. At the other end of rotor element 14 a clutch 34 is connected within the rotor via an annular clutch input member 32. This clutch input member in turn carries a clutch reaction member 33 against which a clutch driven plate 34a is clamped by a clutch pressure plate 35. Pressure plate 35 is in turn supported via torque straps 36 from rotor 14 via flange 37 formed on clutch input member 32. Also supported from flange 37 is an annular diaphragm spring support member 38 against which the outer periphery of diaphragm spring 39 reacts.

The support of rotor element 14 from bearing 17 is via a disc-shaped member 17a which is also secured to flange 37. As will be described later, the disc-shaped support member 12 the torque straps 36 and the diaphragm spring support member 38 are all secured to the flange 37 by studs 40 which are accessible via openings 41 in the cover 11.

Driven plate 34a is supported from a gearbox input shaft 42 via a sleeve 43 and diaphragm spring 35 is operated by concentric slave cylinder 18 against the action of bias spring 17b.

Concentric slave cylinder 18 comprises a first housing portion 44 which includes a hydraulic inlet 45 and which is secured to housing 11 via a spring clip 46. Supported from housing portion 44 is an inner sleeve-like housing portion 47 and an outer housing portion 48 between which an annular piston 49 is axially slideable. Piston 49 forms with housing members 48 and 47 a pressure chamber 50 which communicates with the inlet 45 via an axial drilling 51 in housing portion 47. Piston 49 is connected with belleville spring 39 by a clutch release bearing 52 and a diaphragm finger operating ring 53 against which spring 17b also reacts.

Thus clutch 34 is released by pressurising chamber 50 via inlet 45 to pull diaphragm spring 39 away from pressure plate 35 in a conventional manner.

As will be appreciated the above ESAD unit is particularly compact since both the torsional vibration damper 15 and the drive clutch 34 are both hdused radially within the rotor element 14. Also, the rotor element is well supported at axially spaced locations at one end via the torsional vibration damper 15 and at the other end from the housing 11 of the ESAD unit via bearing 17, disc 17a and clutch input member 32.

A further benefit of the above construction is that it is relatively easily assembled by securing a first sub-assembly comprising the rotor14, torsional vibration damper 15 and clutch input and reaction members 32 and 33 to the engine crankshaft using studs (not shown). A second sub-assembly comprising the housing 11 , stator 13, clutch actuator 18 and the remainder of the clutch including the pressure plate 34a is then secured in position using the studs X. The studs 40 are then inserted through the openings 41 of the housing to secure the disc-shaped support member 17a diaphragm support member 38, and torque straps 36 to the flange 37 on the clutch input member.

As will be appreciated, the concentric slave cylinder actuator 18 may have its various housing members formed either from metal or plastics material.

Figure 2 shows a similar ESAD unit to that shown in figure 1 with the exception that the output member 20 of the torsional vibration damper 15 is supported from the sleeve 43 which mounts the driven plate 34a on the gearbox input shaft 42 via bearing flange 21.

Similarly, in the arrangement shown in figure 3, the output member 20 of the torsinal vibration damper 15 is directly supported from the end of the gearbox input shaft via bearing flange 21 from an annular projection 22a on the crankshaft rather than from the sleeve 43 or the crankshaft 16.

Figure 4 shows an ESAD unit similar to that shown in figure 1 with the exception that the housing 11 is in two portions, an outer annular portion 11 A which carries the stator element 14 and a disc-like end cover portion 11B on which the clutch actuator 18 is mounted. These two portions of the housing are bolted together at 11C.

Such an arrangement greatly facilitates the assembly and servicing of the ESAD unit.

Figure 5 shows a further variant of the housing 11 of the ESAD unit in which the housing incorporates internal passageways 11 D for the passage of coolant. As will be appreciated, the two-piece housing construction shown in figure 4 could also include the coolant passageways 11 D of figure 4.

Figure 6 shows an alternative form of concentric slave cylinder 60 which is supported from a flange 11 E of the housing 11. In this form of actuator the piston member 61 is fixed to housing flange 11 E and the inner and outer body sleeves 62 and 63 are displaced axially relative to the fixed piston. Sleeve 62 operates diaphragm spring 39 via release bearing 52.

As will be appreciated all the above described concentric slave cylinder actuators are designed to operate so-called pull-type diaphragm spring arrangements.

Figure 7 shows a concentric slave cylinder 70 designed to operate a push-type diaphragm spring 39. The actuator 70 comprises a two-piece housing 71 supported from ESAD housing 11 and within which an annular piston 72 is slideable. Pressurisation of the working chamber 73 formed between housing 71 and piston 72 displaces piston 72 to the left as viewed in figure 7 thus pivoting diaphragm spring 39 on spring pivot 38a formed on spring support member 38 to disengage pressure plate 35 and hence allow retraction of the pressure plate by the torque straps 36.

Figure 8 shows a further pull-type clutch actuating arrangement in which torque straps 36 are eliminated and the driving torque transmitted to pressure plate 35 is reacted by splined portions 35a on the outer periphery of the pressure plate which engage co-operating formations 32a on the clutch input member 32. As is conventional in such an arrangement the diaphragm spring 39 is clipped to the pressure plate by clips 35b.

Figure 9 shows a further form of clutch in which the torque transmitted to the pressure plate 35 is reacted via the diaphragm spring 39 itself using splines 39a provided on the outer periphery of the diaphragm spring which engage corresponding formations 38b on the spring support member 38.

Figure 10 shows a further variant of the arrangement shown in figure 1 in which the driven plate 34a also includes its own circumferentially spaced damping compression springs 34b and its own circumferentially acting friction device 34c. This further contributes to the mechanical damping of torsional vibrations within the ESAD unit.

Figure 11 shows a further form of torsional vibration damper which includes two pairs of circumferentially acting springs 23A and 238 respectively (see figure 12). Between the input member 19 and the output member 20 is disposed a central member 9 which includes spring windows 8 which register with windows 24 and 25 in members 19 and 20.

This arrangement is shown diagrammatically in figures 13A to 13B in which only one spring from each pair 23A and 23B is shown for simplicity. Referring to figure 13A this shows the damper in its start or nil deflection position. On initial movement of the input member 19 (see figure 13B) spring 23A is compressed between one end 24i of one of the windows 24 and an end 8i of one of the windows 8 in central member 9. Spring 23A also moves central member 9 which in turn compresses spring 23B between one end 8ii of the other window 8 and an end 25i of one of the windows 25. Thus springs 23A and 23B are compressed in series and, if springs 23A and 23B are of the same rate, member 9 only moves half the distance that member 19 moves.

This series deflection of the springs 23A and 23B continues until (as shown in figure 13C) spring 23A contacts the end 25ii of the other window 25. At this point the end 24ii of the second window 24 also begins to compress the spring 23B against the end 25i of the first window 25. Thus any further relative rotation of the input and output members 19 and 20 compresses both springs 23A and 23B in parallel and member 9 is no longer used to transmit force between members 19 and 20. The parallel loading of springs 23A and 23B results in a step change in the spring rate. If both pairs of springs 23A and 23B are of the same rate and length then there will be a step change of four times in the spring rate opposing the relative rotation of the input and output members.

The above series/parallel damping spring arrangement produces a damping characteristic with a relatively low stiffness and large relative rotation during the initial angle of rotation when the springs 23A and 23B are acting in series and a step change in stiffness and a much reduced relative rotation when the springs 23A and 23B begin to act in parallel. Such a characteristic is particularly good in providing a greater level of control on the relative rotation of the members 19 and 20 when they begin to approach their maximum relative rotation positions. Pairs or sets of springs can be used which have different rates, and can be used in conjunction with suitable delays to alter the damping characteristics. Nested springs of different lengths can also alter the characteristics by introducing further delays and rate changes. The spring characteristics need not be the same in both directions of relative rotation so that the damper performs differently in the drive and overrun conditions.

Although the above series/parallel spring damper has been described above for use with an ESAD unit, it will be appreciated that such a damper could be used on its own or, with the addition of one of more damping means described above in items i) to v), between an engine and vehicle drive-line to damp torsional vibrations. It will also be appreciated that such a series/parallel spring damping arrangement could be used between the input and output masses of a twin mass flywheel either on its own or with the addition of one or more of the damping means described above in items i) to v).

Figure 14 shows an arrangement in which a pull-type clutch is operated by an external actuator 80 via a clutch operating lever 81 which is pivoted at 82 on an outer housing (not shown) attached to the associated engine. Lever 81 moves clutch release bearing 52 via a sleeve 83 which is supported from housing 11 via a plain bearing 84.

Figure 15 shows a corresponding push-type clutch actuation arrangement in which an external actuator 90 operates via a lever 91 which is pivoted at 92 and which moves the diaphragm spring 39 via a sleeve 93 supported from housing 11 via a plain bearing 94.

Figure 16 shows an arrangement basically similar to that shown in figure 1 and in which components of a similar function to figure 1 have therefore been similarly numbered. Flywheel 16 is provided with pockets 16a which receive damper springs 23. Damper 15 has two input members 19a and 19b which are rivetted to each other and to the flywheel 16 by rivets diagrammatically shown at 16b. The output member 20 of the damper is secured via flanges 20a and 20b to the rotor element 14 and is supported from a flange 16c on the flywheel via a plain L-shaped bearing 16d. On either side of output member 20 are friction washers 20c and 20d respectively. An L-shaped annular friction reaction member 20e is splined into right hand input member 19b and the belleville spring 27 operates between the member 19b and the reaction member 20e to complete the friction damping device 26. The flywheel 16 is bolted to the crankshaft 22 by bolts 6. The remainder of the installation is as described in relation to figure 1.

The above use of two axially spaced damper input members 19a and 19b which are rivetted together by rivets 16b can also be applied to the series/parallel damper shown in figure 11 as shown diagrammatically in figure 17.

Claims

1 ) An ESAD unit of the kind specified in which the inner rotor element is driven from the associated engine via a torsional vibration damper located radially within the rotor element.

2) An ESAD unit according to claim 1 in which the torsional vibration damper comprises an input member for connection with the associated engine and an output member connected with the rotor element, the input and output members rotating relative to each other in response to torsional vibrations emitted by the engine and one or more of the following damping means operating between the input and output members to resist such relative rotation: -

i) single or multi- stage circumferentially acting compression springs;

ii) relatively rotatable friction members biased into frictional contact;

iii) bob weight linkages connecting the input and output members which provide a speed dependent damping effect;

iv) viscous dampers, and

v) Elastomeric blocks loaded in compression.

3) An ESAD unit of the kind specified in which the rotor is driven from the associated engine via a torsional vibration damper located radially within the rotor element and the rotor is supported at two locations spaced axially of the rotor, one rotor support being from a non-rotatable housing of the unit and the other rotor support being via the torsional vibration damper from a crankshaft of the associated engine and/or from an input shaft of an associated transmission.

4) An ESAD unit of the kind specified in which the rotor is driven from a crankshaft of the associated engine via a torsional vibration damper located radially within the rotor element and the rotor drives an input shaft of an associated transmission via a clutch also located radially within the rotor element.

5) An ESAD unit according to claim 4 in which the torsional vibration damper comprises an input member for connection with the associated engine and an output member connected with the rotor element, the input and output members rotating relative to each other in response to torsional vibrations emitted by the engine and one or more of the following damping means operating between the input and output members to resist such relative rotation: -

i) single or multi- stage circumferentially acting compression springs;

ii) relatively rotatable friction members biased into frictional contact;

iv) viscous dampers, and

v) Elastomeric blocks loaded in compression.

6) An ESAD unit according to claims 4 or 5 in which the rotor is supported at two locations spaced axially of the rotor, one rotor support being from a non- rotatable housing of the unit and the other rotor support being via the torsional vibration damper from a crankshaft of the associated engine and/or from an input shaft of an associated transmission.

7) An ESAD unit according to any one of claims 4 to 6 in which the clutch is of the pull or push type and is actuated by an hydraulic concentric slave cylinder which surrounds the input shaft and is supported from a housing of the ESAD unit or by an hydraulic cylinder which is located outside the housing of the ESAD unit.

8) An ESAD unit according to claim 7 in which the clutch is of the single or multi-plate type and uses organic or cerametallic friction material.

9) An ESAD unit according to any one of claims 4 to 8 in which the output of the torsional vibration damper is connected with the rotor element and an input member of the clutch is also connected with the rotor element and supports a clutch reaction member, a clutch driven plate being clamped against the reaction member by a pressure plate under the action of a belleville spring which reacts back to the rotor element, the pressure plate being non-rotatably located relative to the reaction member.

10) An ESAD unit according to claim 9 in which the reaction of the belleville spring and the non-rotatable location of the pressure plate relative to the reaction plate is via the input member of the clutch.

11) An ESAD unit according to claim 10 in which clutch torque straps are each connected at one end to the pressure plate and are also connected at their other end to the clutch input member.

12) An ESAD unit according to any one of claims 4 to 11 in which an annular clutch support plate is mounted adjacent its outer periphery on the rotor and is mounted at its inner periphery from the ESAD housing via a rotor support bearf g.

13) An ESAD unit according to claim 12 in which the rotor support bearing is carried on a concentric slave cylinder supported from the housing.

14) An ESAD unit according to claim 9 in which the clutch driven plate is connected with the transmission input shaft via a splined sleeve.

15) An ESAD unit according to claim 14 in which the splined sleeve supports the output member of the torsional vibration damper.

16) An ESAD unit according to claims 14 or 15 in which the central portion of the driven plate of the clutch includes circumferentially acting damping springs and/or friction damping to further attenuate torsional vibrations.

17) An ESAD unit according to claim 1 or 2 in which the rotor drives an input shaft of an associated transmission via a clutch located axially outside the rotor element the clutch having a reaction member located axially alongside one end of the rotor element and supported therefrom.

18) An ESAD unit of the kind specified which includes an outer housing in several parts, an annular portion which is supported from the engine and which carries the stator element outside the rotor element and a disc-like end cover which closes-off the annular portion and supports a clutch actuator.

19) An ESAD unit according to claim 18 in which the annular portion of the housing includes internal passageways for the passage of coolant therethrough.

20) A method of assembling an ESAD unit of the kind specified in which the rotor element is driven from a crankshaft of the associated engine via a torsional vibration damper located radially within the rotor element and the rotor element drives an input shaft of an associated transmission via a clutch also located radially within the rotor element, the method comprising:-

21 ) A torsional vibration damper comprising an input member for connection with an associated engine and an output member for connection with a drive-line, and a damping means acting between the input and output members to resist relative rotation of the members, the damping means comprising groups of circumferentially acting compression springs which are arranged to operate in series to resist the relative rotation of the input and output members during an initial angle of relative rotation of the members and then, during a subsequent angle of relative rotation, act in parallel to resist further relative rotation.

22) A damper according to claim 21 in which additional damping means selected from one or more of items i) to v) of claim 2 may also act to resist the relative rotation of the input and output members.

23) A twin mass flywheel having relatively rotatable input and output masses with a damper according to claim 21 or 22 acting between the masses to resist relative rotation of said masses.

24) An ESAD unit of the kind specified in which the rotor is driven from the associated engine via a damper according to claim 21 or 22.

25) An ESAD unit of the kind specified constructed and arranged substantially as hereinbefore described with reference to and as shown in any one of the accompanying drawings.

26) A torsional vibration damper constructed and arranged substantially as hereinbefore described with reference to and as shown in figures 11 to 13 of the accompanying drawings.