DE102016201548B4 - Freewheel and starter with the freewheel - Google Patents

Abstract

Freewheel (1) for a starting device with an inner part (2), an outer ring (3) and between the inner part (2) and the outer ring (3) limited displaceable arranged locking members, wherein the locking members clamping blocks (4) having a curved inner profile (6) and a curved outer profile (9), wherein the clamping blocks (4) in a region between the curved inner profile (6) and the curved outer profile (9) are tapered, characterized in that either the inner part (2) a curved inner raceway (5) and the outer ring (3) having a curvature (7) provided curved outer raceway (8) or the inner part (2) with a curvature (7) provided curved inner raceway (5) and the outer ring (3) has a curved Outer raceway (8).

Description

The invention relates to a freewheel. Furthermore, the invention relates to a starting device comprising the freewheel.

Freewheels have long been known from the prior art. In the DE 10 2005 034 039 A1 is a roller freewheel and in the DE 2836114 A1 is described a sprag freewheel. Also known is a freewheel variant of the DE 10 2010 052 921 A1 with a clamping contour on the inner and outer raceway.

The power density of roller or sprag freewheels is determined by the maximum service life of the contact between clamping element and raceway, cf. Hertzian contact. The end of the service life is usually material fatigue in the raceway or on the clamping elements themselves.

In conventional roller and sprag freewheels, the radii of curvature between the clamping element and track are usually very different or even in opposite directions. This creates an approximately linear contact that has to endure a high pressure.

In the DE 10 2010 052 921 A1 a variant is described in which approaches by recesses on the inner and outer race, the curvature of the track to the roller radius.

It is therefore the technical task to overcome the disadvantages of the prior art and to achieve a higher power density. Associated with this is the possibility to reduce the installation space and to transfer more torque with less material input.

The object is achieved in particular by a freewheel for a starting device with an inner part, an outer ring and between the inner part and the outer ring limited displaceable arranged locking members, characterized in that the locking members are clamping blocks, which have a curved inner profile and a curved outer profile.

By providing the clamping blocks a reduction of the pressure between the clamping element and the raceway can be achieved.

Preferably, a curve has a shape that follows a curve, a circular arc or a circle. Preferably, at least one curve, a circular arc or a circle defines the curvature. Particularly preferably, the curvature has a shape that is composed of at least two curves with different geometries and / or circular arcs with different radii.

According to the invention, the clamping blocks are tapered in a region between the curved inner profile and the curved outer profile.

By providing a taper clamping is easily executable.

Preferably, the clamping blocks have a bi-concave shape. As a result, the change from an idle to a torque transmission of the freewheel in a simple manner executable.

The high capacity density of the freewheel allows in particular a narrow construction. This results in the use of new manufacturing technologies, preferably a punching of the outer ring, which can result in a reduction of production costs.

According to the invention, either the inner part has a curved inner raceway and the outer ring has a curvilinear curved outer raceway or the inner part has a curved inner raceway provided with bulges and the outer ring has a curved outer raceway.

Preferably, either the inner part or the outer ring is cylindrical. Preferably, either the inner part or the outer ring has a radius which defines a cylindrical raceway.

By using a cylindrical inner race or a cylindrical outer race, a clamping of the freewheel in any position and without free travel is possible.

Preferably, a contour of the clamping blocks and the outer race can be designed flexibly. Thus, the construction can be tuned such that at massive excess of a "usual" torque of the clamping angle increases in the contact points. With increasing clamping angle increases the slip of the freewheel. Thus, the transmittable torque is limited to a maximum torque. The robust design of the outer ring and the clamping blocks prevents damage to the freewheel.

In a further embodiment according to the invention, a curvature of the inner raceway approximates to a curvature of the inner profile, wherein a curvature of the outer raceway is approximated to a curvature of the outer raceway.

The curvature of the clamping blocks is close to the curvature of the inner race and the curvature of the outer race. When loaded, this results in ideally large contact areas at the contact points. This significantly reduces the pressure.

Preferably, a curvature of the inner race is smaller than a curvature of the inner profile. Preferably, a curvature of the outer race is smaller than a curvature of the outer race.

In a further embodiment according to the invention, a curvature of the inner race corresponds to a curvature of the inner profile, wherein a curvature of the outer race corresponds to a curvature of the outer profile.

This allows an alternative embodiment of the freewheel.

In a further embodiment according to the invention, for clamping the clamping blocks, the inner profile forms a first contact surface with the inner raceway, and the outer profile forms a second contact surface with the outer raceway.

This is a clamp in a simple manner executable.

In a further embodiment of the invention springs for generating a restoring force are provided, which are arranged with a first end to the spring holders of the outer ring and with a second end to the clamping blocks.

Preferably, the clamping blocks in geometry and mass, the position of the springs, and the spring forces are coordinated so that a lifting of the clamping blocks of the inner raceway can be done from a certain speed. As a result, the freewheel can be operated lossless in idle mode.

Furthermore, the object is achieved in particular by a starting device for an internal combustion engine having a freewheel.

The freewheel is suitable for use in the starter drive of an internal combustion engine, in particular a permanently eingespurter starter. By using the clamping blocks with different functional areas, the maximum torque to be transmitted can be limited. Thus, the freewheel is robust against unexpectedly high torque, as they can occur when unsuccessful starting the engine.

The invention will now be exemplified by figures. It shows:

1 a schematic view of the freewheel according to the invention,

2 a schematic plan view of the freewheel 1 .

3 a schematic view of a clamping block of the freewheel,

4 a schematic view of the freewheel in idle and

5 a schematic view of the freewheel with clamped clamp.

1 shows a schematic view of the freewheel according to the invention 1 and

2 shows the freewheel 1 in a schematic plan view.

The freewheel 1 is intended for a starting device for an internal combustion engine. The freewheel 1 has a cylindrical inner part 2 , an outer ring 3 and between the inner part 2 and the outer ring 3 three limited shiftable arranged on locking members. The three locking members are as clamping blocks 4 educated. The clamps 4 have a curved inner profile 6 and a curved outer profile 9 on.

The inner part 2 has a curved inner raceway 5 on. The outer ring 3 indicates according to the number of clamping blocks 4 three vaults 7 on. The vaults 7 form a curved outer raceway 8th of the outer ring 3 out. The inner part 2 has a cylindrical shape. By using a cylindrically shaped inner part 2 results in an inner raceway 5 with a curvature corresponding to the radius of the inner part 2 follows. The clamping of the freewheel takes place in any position and without free travel. The curvature of the inner raceway 5 is due to the curvature of the inner profile 6 approximated. Further, a curvature of the outer raceway 8th is due to the curvature of the outer profile 9 approximated.

For clamping the clamping blocks 4 forms the inner profile 6 with the inner raceway 5 a first contact surface and the outer profile 9 forms with the outer raceway 8th a second contact surface.

The freewheel 1 has three springs 11 on. The feathers 11 are set up, a restoring force for the clamping blocks 4 to create. The three springs 11 are with a first end to spring mounts 10 of the outer ring 3 and with a second end to the terminal blocks 4 arranged.

3 shows a schematic view of the clamping block of the freewheel 1 , As already mentioned above, the clamping blocks 4 a curved inner profile 6 and a curved outer profile 9 on. A cross section of the clamping blocks 4 is in a range between the curved inner profile 6 and the curved outer profile 9 tapered trained. The clamps 4 have a bi-concave shape.

4 shows a schematic view of the freewheel 1 idle (see arrow 12 ) and in 5 is a torque (see arrow 13 ) with a clamped clamp 4 shown.

With increasing clamping angle increases the slip of the freewheel 1 , Thus, the transmittable torque is limited to a maximum torque. The robust design of the outer ring 3 and the clamps 4 prevents damage to the freewheel 1 ,

By providing terminal blocks, the maximum torque to be transmitted is limited. Thus, the freewheel is robust against unexpectedly high torque, as they can occur when unsuccessful starting the engine.

LIST OF REFERENCE NUMBERS

1

freewheel

2

inner part

3

outer ring

4

Klemmstein

5

Inner raceway

6

internal profile

7

bulge

8th

Outer race

9

outer profile

10

spring retainer

11

feather

12

arrow

13

arrow

Claims (6)

Freewheel ( 1 ) for a starting device with an inner part ( 2 ), an outer ring ( 3 ) and between the inner part ( 2 ) and the outer ring ( 3 ) limited shiftable arranged locking members, wherein the locking members clamping blocks ( 4 ), which have a curved inner profile ( 6 ) and a curved outer profile ( 9 ), wherein the clamping blocks ( 4 ) in a region between the curved inner profile ( 6 ) and the curved outer profile ( 9 ) are tapered, characterized in that either the inner part ( 2 ) a curved inner raceway ( 5 ) and the outer ring ( 3 ) one with vaults ( 7 ) provided curved outer raceway ( 8th ) or the inner part ( 2 ) one with vaults ( 7 ) provided curved inner raceway ( 5 ) and the outer ring ( 3 ) a curved outer raceway ( 8th ) exhibit. Freewheel ( 1 ) according to claim 1, wherein a curvature of the inner raceway ( 5 ) to a curvature of the inner profile ( 6 ) and a curvature of the outer raceway ( 8th ) to a curvature of the outer profile ( 9 ) is approximated. Freewheel ( 1 ) according to claim 1, wherein a curvature of the inner raceway ( 5 ) a curvature of the inner profile ( 6 ) and a curvature of the outer raceway ( 8th ) a curvature of the outer profile ( 9 ) corresponds. Freewheel ( 1 ) according to one of claims 1 to 3, wherein for clamping the clamping blocks ( 4 ) the inner profile ( 6 ) with the inner raceway ( 5 ) forms a first contact surface and the outer profile ( 9 ) with the outer raceway ( 8th ) forms a second contact surface. Freewheel ( 1 ) according to one of the preceding claims, wherein springs ( 11 ) are provided for generating a restoring force, which with a first end to spring mounts ( 10 ) of the outer ring ( 3 ) and with a second end to the terminal blocks ( 4 ) are arranged. Starting device for an internal combustion engine having a freewheel ( 1 ) according to any one of the preceding claims.

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