Camshaft adjuster and separating sleeve for a camshaft adjuster

Abstract

A camshaft adjuster has a stator, a rotor rotatable relative to the stator with a hub for receiving a camshaft. First supply ducts and second supply ducts penetrate the hub radially, and a separating sleeve inserted with an end section into the hub and forms an outer axial supply space and an inner supply space which is separate from the former, wherein the outer axial supply space is connected in flow terms to the first supply ducts and the inner axial supply space is connected in flow terms to the second supply ducts. On the outer shell, the separating sleeve includes a number of axial grooves at least partially forming the outer axial supply space connected to the first supply ducts. The separating sleeve includes a number of radial apertures which connect the inner supply space to a second supply line.

Claims

1. A camshaft adjuster comprising: a stator, a rotor rotatable relative to the stator around a rotation axis and having a hub for accommodating a camshaft, first supply channels and second supply channels, separated therefrom, radially penetrating the hub, and a separating sleeve, inserted into the hub with at least one end section, which forms an outer axial supply space and an inner axial supply space, separated therefrom, in the hub, the outer axial supply space being fluidically connected to the first supply channels in an axial plane, and the inner axial supply space being fluidically connected to the second supply channels in the axial plane, the separating sleeve including a cylindrical base body including an outer shell defining an outer circumferential surface of the separating sleeve and a number of axial grooves penetrating partially radially into the cylindrical base body away from the outer shell, the axial grooves at least partially forming the outer axial supply space and which are each fluidically connected to the first supply channels, and that the separating sleeve includes a number of radial apertures fluidically connecting the inner axial supply space to a second supply line.

2. The camshaft adjuster as recited in claim 1 wherein the radial apertures are each situated between the axial grooves in the circumferential direction.

3. The camshaft adjuster as recited in claim 1 wherein the axial grooves each extend to one groove end, and the groove ends and the radial apertures are situated in an axial plane on the end section of the separating sleeve inserted into the hub.

4. The camshaft adjuster as recited in claim 1 wherein the axial grooves empty into a common annular groove on the end of the separating sleeve facing away from the end section.

5. The camshaft adjuster as recited in claim 1 wherein the separating sleeve is angle-oriented, in the hub with the aid of complementary tabs.

6. The camshaft adjuster as recited in claim 1 wherein the axial grooves extend between a first axial end and a second axial end of the outer supply space such the axial grooves are configured to fluidically connect to bores radially outside of the first axial end and to fluidically connect to the first supply channels at the second axial end.

7. The camshaft adjuster as recited in claim 1 wherein the radial apertures are circumferentially aligned with the second axial end in the axial plane.

8. The camshaft adjuster as recited in claim 1 wherein the radial apertures feed directly into the second supply line.

9. The camshaft adjuster as recited in claim 1 wherein the separating sleeve includes a first end received in the hub and a second end protruding outside of the hub, the first end of the separating sleeve including a radially extending cylindrical wall axially abutting a portion of the hub.

10. The camshaft adjuster as recited in claim 9 further comprising a central screw received inside of the separating sleeve axially abutting the portion of the hub from an opposite side as the separating sleeve.

11. The camshaft adjuster as recited in claim 1 wherein the separating sleeve includes a first end received in the hub and a second end protruding outside of the hub, the outer axial supply space including an annular groove at the second end and axial grooves extending from the annular groove to the first supply channels.

12. A camshaft adjuster comprising: a stator, a rotor rotatable relative to the stator around a rotation axis and having a hub for accommodating a camshaft, first supply channels and second supply channels, separated therefrom, radially penetrating the hub, and a separating sleeve, inserted into the hub with at least one end section, which forms an outer axial supply space and an inner axial supply space, separated therefrom, in the hub, the outer axial supply space being fluidically connected to the first supply channels, and the inner axial supply space being fluidically connected to the second supply channels, the separating sleeve including a cylindrical base body including an outer shell defining an outer circumferential surface of the separating sleeve and a number of axial grooves penetrating partially radially into the cylindrical base body away from the outer shell, the axial grooves at least partially forming the outer axial supply space and which are each fluidically connected to the first supply channels, and that the separating sleeve includes a number of radial apertures fluidically connecting the inner axial supply space to a second supply line, the separating sleeve including a first end received in the hub and a second end protruding outside of the hub, the outer axial supply space including an annular groove at the second end and the axial grooves extending from the annular groove to the first supply channels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the present invention are explained in greater detail below on the basis of a drawing.

(2) FIG. 1 shows a schematic representation of an internal combustion engine, including camshaft adjusters;

(3) FIG. 2 shows a radial sectional view of one camshaft adjuster from FIG. 1;

(4) FIG. 3 shows an axial sectional view of one camshaft adjuster from FIG. 1;

(5) FIG. 4 shows a perspective view of a separating sleeve from FIGS. 2 and 3;

(6) FIG. 5 shows a side view of the separating sleeve from FIG. 4; and

(7) FIG. 6 shows an axial sectional view of the separating sleeve from FIG. 5.

DETAILED DESCRIPTION

(8) Reference is hereby made to FIG. 1, which shows a schematic representation of an internal combustion engine 2, including camshaft adjusters 4.

(9) In a manner which is known per se, internal combustion engine 2 includes a combustion chamber 6, which may be opened and closed with the aid of valves 8. The valves are activated by cams 10 on corresponding camshafts 12. A reciprocating piston 14, which drives a crankshaft 16, is furthermore accommodated in combustion chamber 6. The rotation of crankshaft 16 is transmitted on its axial end to camshaft adjusters 4 via driving means 18. In the present example, the driving means may be a chain or a belt.

(10) Camshaft adjusters 4 are each mounted axially on one of camshafts 12, are driven by driving means 18 and, in turn, drive camshafts 12. Camshaft adjusters 4 may change the phase angle of camshafts 12 with respect to crankshaft 16.

(11) Reference is hereby made to FIGS. 2 and 3, which show a radial and an axial sectional view of an example of one of camshaft adjusters 4 from FIG. 1.

(12) Camshaft adjuster 4 is mounted on camshaft 12, which, in the present embodiment, has a first radial bore 20 and a second radial bore 22. The two radial bores 20, 22 may be connected to a pressure connection, which is not illustrated, and to a tank connection of an oil supply, which is not illustrated, via a particular annular groove, for example with the aid of a 4/3-way valve and a rotary transmitter.

(13) A receiving bore 24, into which a separating sleeve 26 is inserted, is provided axially in camshaft 12. A step 28 of receiving bore 24 is provided between first radial bore 20 and second radial bore 22, separating sleeve 26 abutting one end of this step 28. Hydraulic fluid is supplied to or removed from an outer axial supply space 27, which is essentially formed by axial grooves 70 (e.g., see FIG. 5) of separating sleeve 26, via first radial bore 20, while, via second radial bore 22, hydraulic fluid is internally conducted to or discharged from an inner axial supply chamber 29 via receiving bore 24.

(14) Separating sleeve 26 projects with an end section 31 out of receiving bore 24 of camshaft 12. Camshaft adjuster 4 is axially mounted on separating sleeve 26 and camshaft 12. Camshaft adjuster 4 has a stator 30 and a rotor 32, which is rotatably accommodated in stator 30. Rotation axis 33 of rotor 32 is indicated. Stator 30 has an outer ring 34, on which teeth 36 are provided, with which driving means 18 may engage for the purpose of rotatably fixedly connecting stator 30 to crankshaft 16. Separating elements 38, in which through-bores 40 are provided, which guide fixing screws 42, project from outer ring 34 radially to the inside. Fixing screws 42 axially fix covers 44 upstream and downstream from stator 30, whereby the inner chamber in outer ring 34 of stator 30 is closed. Covers 44 each have a through-opening in a central location, through which the camshaft is guided in the case of a camshaft-side cover 44, and through which a central screw 46, which is described below, may be guided in the case of cover 44 facing away from the camshaft. The through-opening of cover 44 facing away from the camshaft is closed by a cover disk 48.

(15) Rotor 32 is rotatably fixedly connected to camshaft 12 via central screw 46. Central screw 46 penetrates receiving bore 24 of camshaft 12. Inner axial supply space 29 is thus designed as an annular chamber between separating sleeve 26 and central screw 46. Rotor 32 has a hub 50, in which camshaft 12 and end section 31 of separating sleeve 26 are accommodated. Radial vanes 52 project from hub 50 and end between separating elements 38 on stator 30. In this way, pressure chambers 54, 56 are provided, which are delimited by hub 50 of rotor 32 and outer ring 34 of stator 30 and, in the circumferential direction of camshaft adjuster 4, by a separating element 38 on stator 30 and a vane 52 on rotor 32. In a direction of rotation of camshaft adjuster 4 which is not illustrated, pressure chambers 54, 56 upstream from a vane 52 of rotor 32 are referred to as advance chambers, while downstream from a vane 52 of rotor 32, they are referred to as retard chambers.

(16) Vanes 52 of rotor 32 have sealing elements 58 on their radial ends, which seal pressure chambers 54, 56 against each other. In a first vane 52 of rotor 32, a holding bore 60 is provided, in which a locking pin, which is not illustrated, may be resettably supported. The locking pin may lock a fixed position of rotor 32 with respect to stator 30, for the purpose, for example, of initially building up a certain operating pressure with the hydraulic fluid in camshaft adjuster 4 when internal combustion engine 2 starts up. A central bore 62 is provided in the center of rotor 32, through which central screw 46 is guided. Vane 52, including holding bore 60, has an enlarged design. To avoid an imbalance of camshaft adjuster 4, opposite vane 52 also has an enlarged design. Hub 50 is penetrated by fluidically separated, radial supply channels 64, 66 from central bore 62 into particular pressure chambers 54, 56. First supply channels 66 lead into pressure chambers 56, while second supply channels 64 lead into pressure chambers 54.

(17) First supply channels 66 each empty into axial grooves 70 (see FIG. 5) of separating sleeve 26 and thus into outer axial supply space 27. In contrast, second supply channels 64 empty into radial apertures 68 of separating sleeve 26, which lead to inner axial supply space 29.

(18) In the present embodiment, first and second supply bores 64, 66 empty into the same axial plane of camshaft adjuster 4. For the sake of clarity, only one of distances 72 between supply bores 64, 66 is provided with a reference numeral in FIG. 3. Axial grooves 70 thus extend to a groove end 73 on end section 31 of separating sleeve 26. Radial apertures 68 of separating sleeve 26 are each introduced between axial grooves 70. Apertures 68 and groove ends 73 are essentially situated in an axial plane.

(19) Since supply channels 64, 66 essentially empty into an axial plane, the rotor may be designed to have a small axial width. The separation of inner supply space 29 and outer supply space 27 takes place via the spacing of groove ends 73 to radial apertures 68. Wall width 72 therebetween is approximately half of the groove width. Groove ends 73 and apertures 68 are spaced a distance from receiving base of hub 50 by a circumferential axial wall on end section 31 of separating sleeve 26. A sealing element, which is not indicated in further detail, is furthermore inserted therein, which is penetrated by central screw 46.

(20) Reference is hereby made to FIGS. 4 through 6, which show a perspective view, a side view and an axial sectional view of separating sleeve 26.

(21) Separating sleeve 26 essentially includes a hollow cylindrical base body 69. A number of axial grooves 70 are introduced into the lateral surface of base body 69. They each end in a groove end 73 on end section 31 of separating sleeve 26 to be introduced into hub 50. Radial apertures 68 are introduced therein between groove ends 73 in a common axial plane. Axial grooves 70 empty into a common annular groove 74 on the other end of base body 69. This annular groove 74 is fluidically coupled with first radial bore 20 of camshaft 12 in the assembled state (see FIG. 2). However, this is illustrated only as an example. Axial grooves 70 may also be provided as a single groove in the circumferential direction of separating sleeve 26. It must only be ensured that hydraulic fluid flowing on the surface of separating sleeve 26 does not enter apertures 68.

(22) Wall width 72 between through-openings 68 and groove ends 73 is correspondingly provided by approximately half the width of the groove.

(23) As is directly apparent from FIG. 3, separating sleeve 26 will be inserted into central bore 62 of rotor 32 at a certain angle orientation. To ensure this angular position during installation without requiring adjustment effort, a tab 76 is provided on separating sleeve 26, which is insertable into an axial groove, which is not illustrated, on rotor 32.

LIST OF REFERENCE NUMERALS

(24) 2 Internal combustion engine 4 Camshaft adjuster 6 Combustion chamber 8 Valve 10 Cam 12 Camshaft 14 Reciprocating piston 16 Crankshaft 18 Driving means 20 First radial bore 22 Second radial bore 24 Receiving bore 26 Separating sleeve 27 Outer axial supply space 28 Step 29 Inner axial supply space 30 Stator 31 End section 32 Rotor 33 Rotation axis 34 Outer ring 36 Tooth 38 Separating element 40 Through-bore 42 Fixing screw 44 Cover 46 Central screw 48 Cover disk 50 Hub 52 Vane 54 Pressure chamber 56 Pressure chamber 58 Sealing element 60 Holding bore 62 Central bore 64 Second supply channel 66 First supply channel 68 Aperture 69 Base body 70 Axial groove 72 Wall width 73 Groove end 74 Annular groove 76 Tab