CN112012863A

CN112012863A - Flywheel mechanism for starter and starter for internal combustion engine

Info

Publication number: CN112012863A
Application number: CN202010478933.7A
Authority: CN
Inventors: 苏祖慰; 李剑
Original assignee: SEG Automotive Germany GmbH
Current assignee: SEG Automotive Germany GmbH
Priority date: 2019-05-29
Filing date: 2020-05-29
Publication date: 2020-12-01
Also published as: DE102019114455A1

Abstract

The invention relates to a freewheel mechanism for a starter of an internal combustion engine and to a starter having such a freewheel mechanism, comprising an inner ring (210), an outer ring (220) and a clamping roller (230) arranged between the inner ring (210) and the outer ring (220) in a wedge-shaped gap (222) with a narrowed end, wherein a helical spring (240) is provided for the clamping roller (230), which helical spring is supported on the outer ring (220) or the inner ring and by means of which a force can be exerted on the clamping roller (230) in the direction of the narrowed end of the wedge-shaped gap (222), wherein at least one recess (251, 252) is formed in the ring (220) supporting the helical spring, into which recess a turn (241) of the helical spring (240) is at least partially inserted, wherein the turn 251 of the helical spring and the at least one recess (251, 220) are formed, 252) The coil spring is configured such that the turns (241) of the coil spring are fixed on at least one spatial axis.

Description

Flywheel mechanism for starter and starter for internal combustion engine

Technical Field

The invention relates to a flywheel arrangement for a starter of an internal combustion engine and to a starter for an internal combustion engine having such a flywheel arrangement.

Background

Flywheels or flywheel mechanisms, also known as overrunning clutches, may be used in starters for internal combustion engines. In this way, it is possible to drive a shaft with a starter pinion by means of an electric motor of the starter motor, which can be engaged, for example, by means of a coupling mechanism into a ring gear of the internal combustion engine. However, once the internal combustion engine itself is running, the shaft can be brought without problems via the flywheel to a higher rotational speed than the electric motor (possibly taking into account the gear ratio) with the starter pinion still engaged, or the electric motor can not be accelerated unnecessarily to a too high rotational speed.

For such freewheel mechanisms, clamping rollers can now be provided, which are pressed into the associated wedge gaps by means of suitable helical springs, so that by clamping them, a torque transmission can be produced between the outer ring and the inner ring of the freewheel mechanism, provided that the ring not driven by the starter (either the inner ring or the outer ring) does not rotate faster than the driven ring. So-called self-locking then exists. As soon as the ring which is not driven by the starter exceeds the other ring which is driven by the starter in its rotational speed, the clamping roller is released against the spring force of the helical spring.

Disclosure of Invention

According to the present invention, a flywheel mechanism for a starter and a starter are proposed having the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims and the subsequent description.

The invention is based on a freewheel mechanism for a starter of an internal combustion engine, having an inner ring, an outer ring and at least one clamping roller arranged in a wedge gap between the inner ring and the outer ring. For the clamping roller, a helical spring is provided which is supported on the outer or inner ring and by means of which a force can be applied to the clamping roller toward the narrowed end of the wedge gap. Support on the outer ring is usual, but-in the case of corresponding constructions-support on the inner ring is also possible. A helical spring is understood here to mean, in particular, a spring with a coiled spring wire. In particular, a compression spring is referred to here. The inner ring is also commonly referred to as the roller collar and the outer ring is referred to as the follower.

Furthermore, the clamping roller and the helical spring, with reference to the inner ring and the outer ring, can preferably be arranged in the axial direction between two limiting members, which are also commonly referred to as follower bases (and are then in particular also integrally formed with the outer ring) and a retaining disk, wherein the clamping roller between the two limiting members, with reference to the inner ring and the outer ring, can have play in the axial direction. This play ensures that the clamping roller can be guided in the guide without interference and that a normal self-locking can be achieved as described above.

It goes without saying that such a freewheel mechanism can also, and usually also, have a plurality of such clamping rollers, which then each have an associated helical spring and an associated wedge gap. The clamping rollers can then preferably also be distributed uniformly along the circumference of the inner ring or the outer ring in order to achieve a uniform locking.

For such freewheel mechanisms, it is necessary to arrange the helical springs appropriately so that they do not jam in the freewheel mechanism in as many positions as possible, for example between the clamping roller and the inner or outer ring or between the clamping roller and one of the limiting members. For this purpose, separate spring holders can be provided, which have a fixed position within the freewheel mechanism and on which the helical springs are fixed or plugged. A simple helical spring can then be used here, but with the additional use of a spring retainer, additional components are required. This can lead to difficulties in manufacturing and increased error-prone.

According to the invention, it is now provided that in the ring supporting the helical spring, i.e. the outer ring or the inner ring, at least one recess, in particular in the form of a groove, is formed, into which the turns of the helical spring are at least partially inserted, wherein the turns of the helical spring and the at least one recess are formed in such a way that the turns of the helical spring (which are at least partially inserted into the recess) are fixed relative to at least one spatial axis. The turns are fixed relative to the spatial axis, which is to be understood here as follows: the turns are fixed or immovable in two opposite directions along the axis. This is in particular the end turn of the helical spring facing away from the clamping roller, i.e. the end turn abutting against the inner or outer ring.

As said at least one axis, an axis is considered which is specified by the axial direction with reference to the inner and outer rings (or the rings supporting the springs), in particular in the plane of extension of the turns, and/or an axis perpendicular to the aforementioned axis in the plane of extension of the turns, and/or an axis perpendicular to the plane of extension (which axis then substantially corresponds to the axis on which the spring force of the helical spring is substantially exerted). Although a certain fixation and improvement can already be achieved with only one of these axes, a more improved fixation will be achieved with two or all three of these axes. In addition to the recesses in the ring, one or two of the mentioned limiting elements can also be used for fixing the turns, against which the relevant turns of the helical spring rest, whereby in particular a fixing is achieved with respect to an axis which is defined by the axial direction with reference to the ring supporting the spring.

In contrast to separate components, such as the spring holders mentioned above, no additional components are now required, but the helical spring can be held securely in place and possible jamming can be avoided. In particular, the helical spring or a certain turn thereof and the at least one recess or groove are configured or shaped and in particular also coordinated with one another, so that the fixing is achieved merely by arranging the relevant turn of the helical spring in the at least one recess or groove. The turns of the helical spring are fixed here in particular by form-fitting and/or force-fitting.

Depending on the desired design, it may be sufficient here to change the ring supporting the coil spring relative to the usual freewheel mechanism, with or without the relevant turns of the coil spring being held.

However, it is particularly advantageous if, in addition to the recess, the relevant turns of the helical spring are also designed or formed accordingly, in particular because an optimum coordination with one another can be achieved in this way.

In this connection, it is also preferred that the maximum dimension of the turns of the helical spring abutting against the at least one holding region in the axial direction and/or in a direction perpendicular thereto in the plane of extension is greater than the respective maximum dimension of at least one other turn, in particular all other turns, of the helical spring. In this case, it is particularly preferred that the winding is designed such that it rests against a corresponding limit of the ring, so that a form fit or force fit can be produced particularly easily.

Advantageously, the at least one recess extends along an axis defined by the axial direction with reference to the inner ring and the outer ring and/or radially outside and/or radially inside the spring receiving chamber in the ring. The spring receiving chamber is in particular a chamber in the ring supporting the spring inside the freewheel mechanism, inside which the helical spring is arranged.

It is also preferred that a further helical spring is provided for the clamping roller, which further helical spring is supported on the ring and by means of which an additional force can be exerted on the clamping roller in the direction of the narrowed end of the wedge-shaped gap, wherein the helical spring and the further helical spring are made from one wire.

With conventional freewheel mechanisms, if two separate (and in itself homogeneous) coil springs are used due to the length of the clamping roller, these can be held in position with a common spring holder, whereas the use of two coil springs made of one wire will achieve the possibility of fixing and holding both in position at the same time, in particular because at least one recess and in particular the relevant wire turn are also configured accordingly. It is then also particularly advantageous if the end turn of the (first) coil spring facing away from the clamping roller is likewise designed as an end turn of the other coil spring facing away from the clamping roller. In other words, a large common end turn can thus be formed, for example, by means of the middle section of the wire, from which end turn the two helical springs then extend further. Preferably, two coil springs are arranged one behind the other in the axial direction with reference to a ring supporting the coil springs. Reference is also made to the drawings and the related description.

The subject of the invention is also a starter for an internal combustion engine with a flywheel mechanism according to the invention. In this case, the starter particularly preferably has an electric motor, by means of which an outer ring of the flywheel arrangement can be driven, and a starter pinion, which is connected or coupled to the inner ring. The starter pinion can in particular also be integrally connected or formed with the inner ring.

To avoid repetition, reference is made to the above description of the freewheel mechanism with regard to the advantages and preferred design of the starter, which applies accordingly here.

Other advantages and designs of the invention will become apparent from the description and drawings.

Drawings

The invention is illustrated schematically in the drawings by means of embodiments and will be described below with reference to the drawings.

Fig. 1 schematically shows a starter according to the invention in a preferred embodiment;

FIG. 2 schematically illustrates a cross-sectional view of a freewheel mechanism according to the present invention in a preferred embodiment;

FIG. 3 shows an enlarged portion of FIG. 2;

FIG. 4 schematically illustrates a perspective view of a portion of a freewheel mechanism according to the present invention in a preferred embodiment;

fig. 5 shows the helical spring of the freewheel mechanism according to the invention in a preferred embodiment in different views.

Detailed Description

Fig. 1 schematically shows a starter 100 according to the invention in a preferred embodiment. Which is used to drive or activate or rotate the internal combustion engine 300.

Starter 100 has an electric motor 130, the drive shaft 115 of which is coupled in a torque-transmitting manner via a planetary gear 140, not shown in detail, to a shaft 135. In a preferred embodiment, flywheel mechanism 200 according to the present invention is coupled to drive shaft 115 in a torque transmitting manner. In particular, the outer ring 220 of the freewheel mechanism 200, also referred to as follower, is coupled with the drive shaft 115, for example via a steep thread not shown here.

The freewheel mechanism 200, in particular the inner ring 210 of the freewheel mechanism 200, also referred to as roller collar, also has an external toothing in the form of a starter pinion 110 at the end facing away from the motor. Between the inner ring 210 and the outer ring 220 of the freewheel mechanism 200, there are arranged pinch rollers 230, which will be described in more detail with reference to the following figures.

Here, axial limiting

elements

215 and 225 are provided for the clamping roller 230. The limiting member 225 is here formed by the outer ring 220 itself, in particular a part thereof, although the limiting member 215 may be designed as a retaining disc, or generally as a disc mounted on the outer ring 220.

The freewheel mechanism 200 can be moved away from the motor 130 (and thus to the left in the figure) on the drive shaft 115 by means of a relay or magnetic switch 120 and a link 125, which is only schematically shown. In this way, the starter pinion 110 may mesh with the ring gear 310 of the internal combustion engine 300 in order to rotate the internal combustion engine 300.

A cross-sectional view of a freewheel mechanism 200 according to the present invention in a preferred embodiment is schematically illustrated in fig. 2. The cross-sectional view is perpendicular to the axis of rotation of the drive shaft 115.

In the example shown, seven clamping rollers 230 are provided between the inner ring 210 and the outer ring 220, which are arranged at a distance from one another in the circumferential direction, in particular at equal distances. It goes without saying that other numbers of pinch rollers may be provided.

Each of these pinch rollers 230 is seated in an associated wedge-shaped gap 222 formed by a special profile of the inner side of the outer ring and the outer side of the inner ring. In addition, for each clamping roller 230, an associated helical spring 240 is provided in the spring receiving chamber 223, which spring bears on the one hand against the clamping roller 230, respectively, and on the other hand against a rear wall of the spring receiving chamber 223, which rear wall is formed in the outer ring 220, respectively, or against a support region 221, on which the helical spring bears. Accordingly, the clamping rollers 230 are respectively forced toward the narrowed ends of the wedge slits 222 by means of the coil springs 240.

This results in that, when the outer ring 220 is rotated and driven in the direction indicated by the arrow (clockwise in the drawing), which is not shown in detail, the inner ring 210 also rotates with it, since the clamping rollers 230 are clamped between the inner ring 210 and the outer ring 220.

However, as soon as the inner ring 210, which is coupled to the starter pinion 110 and the ring gear 310 via the internal combustion engine, for example via a rotating internal combustion engine, reaches a higher rotational speed than the outer ring 220 driven by the electric motor 130, the clamping of the clamping rollers 230 is released, which in this case press against the helical springs 240.

Fig. 3 shows an enlarged section of fig. 2, in which the helical spring 240 and the support region 221 can be seen in detail. Here, it can be seen that the end turns 241 of the helical spring 240 facing away from the clamping roller 230 are supported on the support region 221 and are mounted in recesses or

grooves

251, 252 in the spring receiving chamber 223. These recesses or

grooves

251, 252 run in the axial direction (defined by the axes of the inner and outer rings) and radially outside and inside (with reference to the direction or axis R) the spring chamber 223, or along the edges between the "top cover" and the support region 221 on the one hand and the "bottom" and the support region 221 on the other hand.

In fig. 4 a perspective view of a part of the freewheel mechanism according to the invention is schematically shown in a preferred embodiment, whereby the outer ring or follower 220 can be seen together with a limiting member 225 constructed integrally therewith.

In particular, there is also a holding region 253 formed by the limiting element 225 and thus by a part of the outer ring 220, against which the turns 241 of a coil spring, for example, as shown in fig. 3, rest in partial sections when the coil spring is inserted accordingly.

Fig. 5 shows a helical spring of a freewheel mechanism according to the invention in a preferred embodiment in different views, wherein a further helical spring 240 'is additionally provided, wherein the helical spring 240 and the further helical spring 240' are made from one wire and have a common end turn 241.

Views (a) and (b) show the two helical springs 240, 240 'in different perspective views, while view (c) shows how the two helical springs 240, 240' abut against the pinch roller 230.

In view (a), the plane of extension E of the turns or end turns 241 is shown, as can be understood in particular within the scope of the invention. This extension plane E extends on the one hand along an axis a, such as also shown in fig. 4, defined by the axial direction with reference to the inner and outer rings, and on the other hand along an axis R' that substantially or at least coincides with the radial direction or with a greater component of the axis R as shown in fig. 2.

With respect to the last-mentioned axis it is to be noted that the plane of extension or axis R' in fact encloses an angle with the axis R, which angle is for example related to the specific design of the protuberance 121 (in particular the inclination of its plane) against which the end turns 241 rest.

Furthermore, an axis L is shown, perpendicular to the extension plane E, which axis substantially corresponds to the following direction: in this direction, the two coil springs 240, 240' may exert their spring force.

Also by Δ A in view (b)_AThe development distance or maximum dimension of end turns 241 along axis A in extension plane E is shown, Δ A'_AThe relative extension or maximum dimension of the remaining turns of one of the two coil springs is shown.

By using Δ A in addition_RThe development distance or maximum dimension of the end turns 241 in the extension plane E along an axis R 'perpendicular to the axis A, denoted by Delta A'_RThe relative extension or maximum dimension of the remaining turns of one of the two coil springs is shown.

It can be seen that the end turns 241 have a substantially rectangular shape, but with rounded corners, while the remaining turns are substantially round or oval.

With these dimensions of the end turns 241 with respect to the remaining turns, but also due to the generally rectangular special shape (or trend thereof) of the end turns 241 as a whole, a particularly simple and effective fixation in the recesses or

grooves

251, 252 is possible.

Here, reference is also made to fig. 4, in which recesses 251 and 252 can be clearly seen, into which the end turns 241 can be inserted with their sections extending along the axis a, in order to achieve a fixing both by form fit and force fit.

By means of the proposed fixing of the windings of one or both coil springs, a particularly simple production of the freewheel mechanism is possible, in particular with regard to the arrangement of the coil springs, while the coil springs are reliably positioned and held.

For the sake of completeness only, it is also mentioned that the specific shape of the helical spring, in particular its cross section, and further in particular beyond the end turns 241, can also be designed in other ways. For example, oval, polygonal, in particular rectangular cross sections are conceivable, or other elongated cross sections are also conceivable. In particular, for an elongated cross section, instead of two coil springs only one coil spring may also be sufficient. However, even for two coil springs, the specific shape or cross section of the two coil springs does not necessarily have to be the same.

Claims

1. A freewheel mechanism (200) for a starter (100) of an internal combustion engine (300), having an inner ring (210), an outer ring (220) and clamping rollers (230) arranged between the inner ring (210) and the outer ring (220) in a wedge-shaped gap (222) with narrowed ends,

wherein a helical spring (240) is provided for the clamping roller (230), which helical spring is supported on the outer ring (220) or the inner ring and by means of which a force can be exerted on the clamping roller (230) towards the narrowed end of the wedge-shaped gap (222),

wherein in a ring (220) supporting the coil spring at least one recess (251, 252) is formed into which a turn (241) of the coil spring (240) is at least partially inserted, wherein the turn of the coil spring and the at least one recess (251, 252) are formed such that the turn (241) of the coil spring is fixed on at least one spatial axis (A, R', L).

2. The freewheel mechanism (200) according to claim 1, characterized in that, the turns (241) of the helical spring (240), which are at least partially inserted in at least one recess, and the at least one recess (251, 252) are configured so that the turns (241) of the helical spring are fixed in the plane of extension (E) of the turns on an axis that is defined by the axial direction (a) with reference to the inner ring (210) and the outer ring (220), and/or on an axis (R') that is perpendicular to the aforementioned axis, and/or on an axis (L) that is perpendicular to the plane of extension.

3. The freewheel mechanism (200) according to claim 1 or 2, characterized in that, the turns (241) of the helical spring and at least one recess are configured so that the turns (241) of the helical spring, which are at least partially inserted in the at least one recess, are fixed by form-fit and/or force-fit.

4. The freewheel mechanism (200) according to one of the preceding claims, characterized in that, it contains turns (241) of the helical spring inserted at least partially in the at least one recess, whose maximum dimension (Δ'_A、ΔA_R) Greater than a respective maximum dimension (Δ A ') of at least one other turn of the helical spring (240)'_A、ΔA'_R)。

5. The freewheel mechanism (200) according to any one of the previous claims characterized in that, the at least one recess (251, 252) stretches along the axis that is specified by the axial direction (a) with reference to the inner ring (210) and the outer ring (220), and/or stretches radially outside and/or radially inside a spring-housing cavity, and/or stretches along the edge of the spring-housing cavity.

6. The freewheel mechanism (200) according to any of the previous claims characterized in that, it contains at least one recess, which is configured in the form of a groove.

7. The freewheel mechanism (200) according to one of the preceding claims, characterized in that, the clamping roller (230) and the helical spring (240) are placed in the axial direction (A) between the two limiting members (215, 225) with reference to the inner ring (210) and the outer ring (220), wherein the turns (241) of the helical spring abut on the two limiting members (215, 225).

8. The freewheel mechanism (200) according to one of the preceding claims, characterized in that, the turns (241) of the helical spring that are at least partially inserted in the at least one recess are configured as the terminal turns of the helical spring (240) that face away from the clamping roller (230).

9. The freewheel mechanism (200) according to one of the preceding claims, characterized in that, for the clamping roller (230), another helical spring (240') is provided, which is supported on a ring (220), which supports the helical spring (240), and by means of which an additional force can be applied to the clamping roller (230) in the direction of the narrowed end of the wedge-shaped gap (222), wherein the helical spring (240) and the other helical spring (240') are made of one wire.

10. The freewheel mechanism (200) according to claim 8 and 9, characterized in that, the end turn (241) of the helical spring facing away from the clamping roller (230) is also designed as the end turn of another helical spring (240') facing away from the clamping roller (230).

11. A starter (100) for an internal combustion engine (300) with a freewheel mechanism (200) according to any one of the preceding claims.

12. The starter according to claim 11, with an electric motor (130) by means of which an outer ring (220) or an inner ring (210) of the flywheel mechanism (200) can be driven, and with a starter pinion (110) which is connected or coupled with the other ring, respectively.