Camshaft phaser

Abstract

A camshaft phaser for the adjusting valve timing of a combustion engine includes a stator and a rotor that can rotate relative to the stator. The rotor is connected to one end of the camshaft via an adapter as well as via a sprocket which is fixedly mounted to the stator. The sprocket is slideably mounted about the camshaft with a first guiding section and is slideably mounted about the adapter with a second guiding section.

Claims

1. A camshaft phaser for adjusting a valve timing of a combustion engine, the camshaft phaser comprising: a stator; a rotor rotatable relative to the stator, wherein the rotor is connected via an adapter to an end of a camshaft, a chain sprocket connected to the stator, the chain sprocket having a cylindrical inner guiding surface; wherein the guiding surface of the chain sprocket is mounted about a first guiding section of the camshaft and about a second guiding section of the adapter; wherein a contact surface between the rotor and the adapter, as well as a contact surface between the adapter and the camshaft, are equipped with surface features configured to enhance friction.

2. The camshaft phaser according to claim 1, wherein a passage opening for the centering of the camshaft and of the adapter is within the chain sprocket.

3. The camshaft phaser according to claim 1 wherein a ledge is formed on the adapter and configured to center the adapter with the rotor.

4. The camshaft phaser of claim 1 wherein the adapter and the chain sprocket are produced in one respective sintering process.

5. The camshaft phaser of claim 1, wherein an elevation or a depression is formed at the adapter for a form-fitting connection with the rotor or with the camshaft.

6. The camshaft phaser of claim 1, wherein a recess is formed at the adapter for receiving a pin configured to inhibit twisting or supply oil through the adapter.

7. The camshaft phaser of claim 6, wherein the recess is a passage opening.

8. A camshaft phaser assembly comprising: a stator, a rotor and a chain sprocket connected to one end of a camshaft of a combustion engine, the chain sprocket having a cylindrical inner surface defining a guiding surface; an adapter arranged between the rotor and the camshaft; wherein the guiding surface of the chain sprocket is mounted on the camshaft with a first guiding section, and mounted on the adapter with a second guiding section; wherein the adapter is connected to the camshaft; and a compound structure including at least the adapter and the camshaft inserted into and centered with respect to a passage opening of the chain sprocket wherein a recess is formed at the adapter, and the recess receives a pin.

9. A camshaft phaser for adjusting valve timing of an internal combustion engine, the camshaft phaser comprising: a stator; a rotor rotatable relative to the stator; a sprocket fixedly mounted to the stator, the sprocket having a cylindrical inner surface configured to contact an outer surface of a camshaft in a slideable manner to enable relative rotation between the sprocket and camshaft, and an outer surface defining a recess configured to receive a chain or belt; and an adapter axially aligned with the rotor and configured to transfer rotational movement between the rotor to the camshaft, the adapter located radially inward of the sprocket and having an outer surface contacting the inner surface of the sprocket in a slideable manner to enable relative rotation between the adapter and the sprocket; wherein a recess is formed at the adapter, and the recess receives a pin.

10. The camshaft phaser of claim 9, wherein the adapter has an end surface that engages a corresponding end surface of the camshaft such that the adapter and camshaft are coupled in an end-to-end relationship.

11. The camshaft phaser of claim 9, wherein the rotor, the adapter, and the camshaft are axially aligned and define a common through hole.

12. The camshaft phaser of claim 9, wherein the rotor, the adapter, and the camshaft define a common through hole that is located within a center hole of the sprocket.

13. The camshaft phaser of claim 9, wherein the adapter is disposed axially between the rotor and the camshaft.

14. The camshaft phaser of claim 9, wherein the adapter defines a ledge on an end surface that faces the rotor, and the rotor defines a corresponding groove that receives the ledge to center the rotor with respect to the adapter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a hydraulic camshaft phaser in accordance with the vane principle, in which the chain sprocket is mounted on the camshaft with a first guiding section and on the adapter with a second guiding section, and

(2) FIG. 2A illustrates a front end view of the rotor; FIG. 2B illustrates a side view of the adaptor; and FIG. 2C illustrates an end view of the camshaft, according to an embodiment.

DETAILED DESCRIPTION

(3) FIG. 1 depicts a hydraulic camshaft phaser 1 for adjusting the opening and closing times of the intake or exhaust valves of a combustion engine. The camshaft phaser 1 comprises a stator 2 and a rotor 3, whereby the rotor 3 is mounted in the stator 2 in such a way that it rotates with the stator 2 around a common rotation axis. Rotor 3 is connected via an adapter 4 to one end 6 of a camshaft 5 of the combustion engine. On its end that is facing away from the camshaft 5, stator 2 is closed by a cover 20, whereby the cover 20 is connected to a chain sprocket 7 of the camshaft phaser by means of openings in stator 2. To accomplish this, bore holes 22 with a thread 23 are arranged in the chain sprocket 7, so that the cover 20 can be attached to the chain sprocket 7 by means of screws 21, which can be inserted into the openings in stator 2 and tightened in these threads 23. A passage opening 10 is arranged at the chain sprocket 7, which forms a guiding surface for the chain sprocket 7. At the end 6 of the camshaft 5, a first guiding section 8 is formed, which can engage with the guiding surface of the chain sprocket 7. A second guiding section 9 is formed at adapter 4, which can also engage with the guiding surface on the chain sprocket 7. Between the first guiding section 8 at the end of camshaft 5 and the second guiding section 9 at adapter 4, a free punch 25 is provided on the adapter 4 in order to accommodate a locking for the chain sprocket 7. Alternatively, adapter 4 can also be arranged with a constant diameter on its outer diameter.

(4) A first section 29 is designed on the chain sprocket 7, which is provided for the fastening of the chain sprocket 7 at stator 2. In addition to this, a ledge 17 is provided at the chain sprocket 7, which is arranged with a gear tooth system 18 in order to accommodate a chain, by means of which the camshaft phaser can be connected to a camshaft of the combustion engine. Between the first section 29 and the ledge 17, a recess 19 is provided in order to arrange for the necessary clearance for the chain. It is furthermore possible to implement specifications with regards to the position of the chain in relation to camshaft 5 via the width of the chain sprocket 7 in a constructive manner, without having to change further components.

(5) The adapter 4 is designed as a simple, mainly cylindrical body and features a ledge 11 at its end that is facing towards rotor 3, for the centering of the position of adapter 4 and of rotor 3 towards each other. The adapter 4 further comprises recesses 12 into which centering pins or other means can be inserted for an angular alignment, in order to ensure a position orientation with regards to rotor 3 towards adapter 4 and/or with regards adapter 4 towards camshaft 5. Alternatively or additionally, it is possible to provide recesses 12 at adapter 4, in particular passage bore holes for the oil supply between camshaft 5 and rotor 3. Hereby adapter 4 is positioned with a first contact surface 14 flat on rotor 3 of the camshaft phaser 1, and with a second contact surface 15 flat on the end 6 of camshaft 5.

(6) The connection of rotor 3 to camshaft 5 is carried out via adapter 4 by means of a central screw (not illustrated) or by means of another kind of fixation. The danger of a tilting of the adapter 4 in relation to camshaft 5 is to be reduced as much as possible in this way, in order to achieve the best possible rotation and to reduce the oil leakage at the axial bearing of the camshaft phaser 1. The free punch 25 furthermore provides the possibility to compensate slight errors in the coaxiality and in the rotation, so that the components of the camshaft phaser 1 can be designed in a comparatively simple and cost-effective manner. Adapter 4 is centered by the chain sprocket 7 towards the end 6 of camshaft 5, by means of which a geometrically simple and comparatively cost-effective adapter 4 is possible. There is furthermore the possibility to save construction space in radial direction, since such an adapter 4 requires less construction space than an adapter 4 which would be centered directly by camshaft 5.

(7) Adapter 4 of the suggested camshaft phaser 1 is hereby centered along with the end 6 of camshaft 5 by means of the guiding surface of the chain sprocket 7. It is hereby possible that adapter 4 and the chain sprocket 7 can be produced particularly cost-effective in one sintering process, whereby an additional, cost-intensive processing of additional centering surfaces can be omitted. As a result, the assembly of the camshaft phaser 1 is simplified as well, since it is no longer necessary to adjust a second centering surface and thus one working process can be eliminated. A compound structure 16 that is made from adapter 4 and camshaft 5 can thereby be inserted into the passage opening 10 of chain sprocket 7, whereby adapter 4 as well as camshaft 5 can be centered at their respective guiding sections 8, 9 by means of the guiding surface of the chain sprocket 7.

(8) By means of the elements such as e.g. centering pins, that can be inserted into the recesses 12, which are preferably designed as passage openings, it is possible to ensure the angular alignment between adapter 4 and rotor 3 as well as between adapter 4 and camshaft 5, since these elements prevent a twisting between the respective components.

(9) The contact surface 14 between rotor 3 and adapter 4 as well as the contact surface 15 between adapter 4 and the end 6 of camshaft 5 can be equipped with a friction-enhancing structure, in particular with a laser structure, or a corresponding heat treatment, in order to reduce deformation of the components after the assembly by means of a form-fitting connection or to transmit a higher torque at the same pretensioning force.

(10) FIGS. 2A-2C depicts rotor 3, adapter 4 as well as the end 6 of camshaft 5 of the camshaft phaser 1 according to this disclosure. Rotor 3 features a base body 30, from which the blades 24 protrude radially in relation to the rotation axis of rotor 3 into the direction of stator 2. Rotor 3 furthermore comprises openings 28 to accommodate elements, which are arranged in the recesses 12 of adapter 4, in order to prevent a twisting of adapter 4 in relation to rotor 3. The openings 28 in rotor 3 and the recesses 12 in adapter 4 can furthermore be used for the oil supply of the camshaft phaser 1. The rotor 2 further comprises a protection against twisting 13 in form of a recess 26 or of a ledge, by means of which a form-fitting connection can be accomplished towards a corresponding ledge or a corresponding recess at adapter 4. At its end that is facing towards adapter 4, camshaft 5 also comprises a protection against twisting 13 in form of a recess 27 or of a ledge, which can be engaged by means of a corresponding elevation or recess at adapter 4. Additionally or alternatively, it is also possible to provide openings 28 at the end 6 of camshaft 5, in order to accommodate the elements that are inserted into the recesses of adapter 12 and thus to produce a form-fitting connection between adapter 4 and the end 6 of camshaft 5.

LIST OF REFERENCE SIGNS

(11) 1 Camshaft Phaser 2 Stator 3 Rotor 4 Adapter 5 Camshaft 6 End of the Camshaft 7 Chain Sprocket 8 first Guiding Section 9 second Guiding Section 10 Passage Opening 11 Ledge 12 Recess 13 Protection against Twisting 14 first Contact Surface 15 second Contact Surface 16 Compound Structure 17 Ledge 18 Gear Tooth System 19 Recess 20 Cover 21 Screw 22 Bore Hole 23 Thread 24 Blade 25 Free Punch 26 Recess 27 Recess 28 Opening 29 first Section 30 Base Body