Camshaft adjusters and camshaft adjuster units

Abstract

The invention relates to a camshaft adjuster (1) for adjusting the phase of a camshaft (2), comprising a driven element (3) designed to rotate relative to a drive element (4) of the camshaft adjuster (1), and a driven anchor (5) of shaft-shaped design intended to connect the driven element (3) to the camshaft (2) in a rotationally fixed manner, wherein the driven element (3) and the driven anchor (5) are connected to each other via a connecting portion (6), the connecting portion (6) having at least one first section (7) with a higher surface roughness and at least one second section (8) with a lower surface roughness, the first section and the second section adjoining each other in the circumferential direction. The invention also relates to a camshaft adjuster device comprising a camshaft adjuster (1) and a camshaft (2), the camshaft being connected to the driven anchor (5) in a rotationally fixed manner via a surface-structured press fit (14).

Description

Technical Field

[0001] The invention relates to a camshaft adjuster for adjusting the phase position of a camshaft relative to a crankshaft in a motor vehicle drive train. The invention also relates to a camshaft adjuster arrangement having a camshaft adjuster and a camshaft connected thereto. Background Art

[0002] Camshaft adjusters are known in the prior art. For example, DE 10 2004 026 863 A1 discloses a camshaft adjuster for adjusting and fixing the phase position of a camshaft of an internal combustion engine relative to its crankshaft. The camshaft adjuster comprises: a drive wheel driven by the crankshaft; and a driven component fixed to the camshaft, the driven component being mounted on the camshaft or a camshaft extension and driven by the drive wheel. The phase position of the driven component relative to the drive wheel can be adjusted within a certain angular range, and the driven component is fastened to the camshaft or the camshaft extension in a force-fitting manner.

[0003] However, the prior art always has the disadvantage that the camshaft adjuster, in particular the connection between the camshaft adjuster and the camshaft, is complex and cost-intensive to produce. Summary of the Invention

[0004] The object of the present invention is therefore to avoid or at least alleviate the disadvantages of the prior art. In particular, a camshaft adjuster is to be provided which consists of simple components, so that the camshaft adjuster can be manufactured cost-effectively with minimal manufacturing effort.

[0005] This object is achieved by the camshaft adjuster according to the invention. Advantageous developments are described in this document.

[0006] Specifically, the present invention is embodied in a camshaft adjuster for adjusting the phase position of a camshaft relative to a crankshaft in a motor vehicle powertrain. The camshaft adjuster has a driven element designed to rotate within a limited angular range relative to a drive element of the camshaft adjuster. The camshaft adjuster has a shaft-shaped driven anchoring element that is provided for torque-proof connection of the driven element to the camshaft. The driven element and the driven anchoring element are connected to each other via a force-fit and / or material-fit connection, in particular, via a (longitudinal) press fit. The connection has at least one first section with a higher surface roughness and at least one second section with a lower surface roughness (i.e., the second section has a lower surface roughness than the first section), the first and second sections adjoining each other in the circumferential direction. In other words, the connection has a surface structure that is (only) segmented in the circumferential direction. By selectively setting the surface roughness, the connection can be locally strengthened, while at the same time, disadvantages resulting from a higher surface roughness (e.g., stress or chip formation during the joining process) can be locally avoided.

[0007] The driven element can preferably be configured as a sintered component, for example made of sintered metal. The driven anchor can preferably be configured as a rotating component, for example made of low-alloy steel. In this way, low-cost manufacturing can be ensured.

[0008] According to a preferred embodiment, the connection can have a plurality of first sections with a higher surface roughness and a plurality of second sections with a lower surface roughness, alternating in the circumferential direction. The force-fit (press-fit) connection is locally reinforced by the first sections. Simultaneously, deformation during joining / pressing is minimized or compensated by the second sections, or is fixed to a specific area, namely the first section. In other words, the connection is constructed in sections with a higher surface roughness and in sections with a lower surface roughness in the circumferential direction.

[0009] According to a preferred embodiment, the first section can be formed by a surface structure (or surface profile) that is interrupted in the circumferential direction. A surface structure is understood to include, for example, knurling or laser structuring. The surface structure increases the contact surface area of ​​the components to be connected, resulting in a stronger connection.

[0010] The camshaft adjuster can be designed, in particular, as a vane-type camshaft adjuster. The camshaft adjuster includes a hydraulic channel in the driven element and / or the driven anchor for adjusting the driven element relative to the drive element. According to a preferred embodiment, the hydraulic channel can be provided in the second section (or sections) of the connecting portion. This prevents chips from entering the hydraulic channel when the first sections are engaged.

[0011] Alternatively, the camshaft adjuster can also be designed as an electric camshaft adjuster. That is, the design of the surface structure at the connection between the output element and the output anchor can be independent of the type of adjustment.

[0012] According to an advantageous refinement, the second section can be configured as a radial bearing surface for centrally supporting the driven anchor on the driven element. This ensures central support of the two components to be connected. This means that deformation during the engagement / press-fitting of the knurling / surface structure does not affect the radial support.

[0013] It is also advantageous if the contact surface of the driven element has a smaller inner diameter in the region of a second section (or sections) than in the region of a first section (or sections), thereby ensuring that the second section serves as a radial bearing surface.

[0014] Furthermore, it is expedient if the contact surface of the driven anchor has a larger outer diameter in the region of a second section (or sections) than in the region of a first section (or sections), thereby ensuring that the second section serves as a radial bearing surface.

[0015] Furthermore, the driven anchor preferably has a radially outwardly projecting flange in its axial end region, which axially adjoins the first section. This provides an axial stop / limitation for the driven element. Alternatively, the flange can be replaced by a stamped pattern or a form-fitting element, such as a snap ring.

[0016] According to a further preferred embodiment, the camshaft adjuster can have a drive element which is arranged concentrically with the driven element and radially outside the driven element, wherein the driven element is mounted rotatably relative to the drive element within a limited angular range.

[0017] The object of the present invention is also achieved by a camshaft adjuster arrangement having the camshaft adjuster and a camshaft. The camshaft is connected to the driven anchor in a rotationally fixed manner by a surface-structured press fit.

[0018] In other words, the present invention relates to a cost-effective connection of an (electric or hydraulic) camshaft adjuster to a camshaft. In particular, a combination of an anchor and a hub is provided, which, in known hydraulic camshaft adjusters, previously resulted in a complex component that could only be manufactured using a complex sintering process or by complex turning and milling. By separating the anchor from the hub, the hub can be constructed as a simple sintered component, while the anchor can be constructed as a turned part with minimal machining effort. This eliminates the need for additional screw elements and avoids costly welded connections or form-fit connections with play. In particular, an oil-conducting anchor serves as a connecting element between the driven element (hub) and the camshaft and is connected to the driven element and the camshaft via at least one press fit with or without a surface structure. To avoid chipping during joining, the connection between the anchor and the driven element can preferably have a surface structure, for example, an embossed or laser-structured surface structure, only on the circumference outside the radial bore / hydraulic channel. Because the press fit has recesses in the surface structure / knurled region, radial deformation during the knurling does not restrict the bearing function. A flange can preferably be provided on the end face to increase strength during engagement and prevent axial displacement of the driven element. Alternatively, the flange can be replaced by a stamped pattern or a form-fitting element such as a retaining ring / seegering. The cost efficiency is advantageously improved by the press fit, which is reinforced by the locally applied knurling. For cost-effective production, the anchor can be made of low-alloy steel, for example, while the driven element can be made of sintered metal, for example. The knurled recess in the area of ​​the radial bearing segment avoids concentricity errors that may occur when absorbing deformations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described below with reference to the accompanying drawings.

[0020] Figure 1 shows a longitudinal section through a camshaft adjuster with a camshaft,

[0021] Figure 2 A perspective view of a driven element of a camshaft adjuster is shown, and

[0022] Figure 3 A perspective view of the driven anchor of a camshaft adjuster is shown.

[0023] The accompanying drawings are merely schematic and serve only to illustrate the present invention. Identical elements are provided with identical reference numerals. DETAILED DESCRIPTION

[0024] Figure 1The diagram shows a camshaft adjuster 1 and its individual components. The camshaft adjuster 1 serves to adjust the phase position of a camshaft 2 relative to a crankshaft (not shown). The camshaft adjuster 1 is used in a motor vehicle powertrain with an internal combustion engine. The camshaft adjuster 1 has a driven element 3. The driven element 3 is connected or connectable to the camshaft 2 in a rotationally coupled manner. The driven element 3 is designed / prepared to rotate relative to a drive element 4 of the camshaft adjuster 1 within a limited angular range (for phase adjustment). The driven element 3 is designed as a hub. The drive element 4 is connected or connectable to the crankshaft in a rotationally coupled manner.

[0025] The camshaft adjuster 1 has an output anchor 5 . The output anchor 5 is axially shaped. That is, the output anchor 5 is designed as a shaft. In particular, the output anchor 5 is designed as a hollow shaft. The output anchor 5 is designed / prepared to connect the output element 3 to the camshaft 2 in a rotationally fixed manner. Thus, the output anchor 5 serves as a camshaft connection for the camshaft adjuster 1 .

[0026] The driven element 3 and the driven anchor 5 are connected to each other via a force-fit and / or material-fit connection 6. In particular, a press fit, particularly a longitudinal press fit, is formed between the driven element 3 and the driven anchor 5. The radially inner circumference of the driven element 3 is connected to the radially outer circumference of the driven anchor 5 via the connection 6.

[0027] The connection 6 between the driven element 3 and the driven anchor 5 has at least one first section 7 with a higher surface roughness and at least one second section 8 with a lower surface roughness, which adjoin one another in the circumferential direction / viewed circumferentially. The first section 7 and / or the second section 8 are specifically formed on the connection 6, i.e., they are not accidentally formed, for example, due to machining-induced fluctuations. The connection 6 is formed between the contact surface 9 of the driven element 3 and the contact surface 10 of the driven anchor 5. In other words, the first section 7 and / or the second section 8 are specifically introduced / machined into the contact surface 9 of the driven element 3 and / or the contact surface 10 of the driven anchor 5.

[0028] The connecting portion 6 has a plurality of first sections 7 with a higher surface roughness and a plurality of second sections 8 with a lower surface roughness alternating in the circumferential direction. In the embodiment shown, the first sections 7 are formed alternately with the second sections 8 in the contact surface 9 of the driven element 3 and in the contact surface 10 of the driven anchor 5.

[0029] In particular, the first section 7 comprises a surface structure or surface profile that is interrupted in the circumferential direction. In the illustrated embodiment, the first section 7 is formed by knurling with axially parallel grooves. Alternatively, the first section 7 can be formed, for example, by laser structuring. Because the surface structure can generate chips when joining the first section 7, the provision of the second section 8 prevents chip formation in specific areas of the connection 6, namely the first section 7. In other words, the (compressed) connection 6 is only partially reinforced by the surface structure or surface profile.

[0030] The second section 8 is designed as a radial bearing surface for centering the driven anchor 5 on the driven element 3. In particular, the contact surface 9 of the driven element 3 has a smaller inner diameter in the region of the second section 8 than in the region of the first section 7. In particular, the contact surface 10 of the driven anchor 5 has a larger outer diameter in the region of the second section 8 than in the region of the first section 7. This prevents the bearing function from being adversely affected by radial deformations of the first section 7 during the joining process.

[0031] In the embodiment shown, the camshaft adjuster 1 is designed as a vane-type hydraulic camshaft adjuster. The camshaft adjuster 1 has a hydraulic channel 11 for adjusting the driven element 3 relative to the drive element 4. The hydraulic channel 11 connects the radial outside of the driven element 3 with the radial inner space within the driven anchor 5. A central valve for controlling the flow of hydraulic medium through the hydraulic channel 11 is provided in the radial inner space. The hydraulic channel 11 extends in the radial direction through the driven element 3 and / or the driven anchor 5. The hydraulic channel 11 is arranged in one or more second sections 8 of the connecting part 6. That is, the hydraulic channel 11 opens into the contact surfaces 9, 10 in the region of the second section 8. In other words, the first section 7 is arranged (in the circumferential direction) outside the hydraulic channel 11.

[0032] The driven anchor 5 has a flange 12 protruding radially outward. The flange 12 is formed in a circumferential manner, for example, in the form of a flange. The flange 12 is arranged in the axial end area (facing away from the camshaft) of the driven anchor 5. The flange 12 is adjacent to the first section 7 in the axial direction, that is, adjacent to the surface structured portion. The flange 12 forms an axial stop for the driven element 3. Alternatively, a retaining ring can also be used to fix the axial position of the driven element 3 relative to the driven anchor 5. The driven element 3 has an axial recess 13 on the end side. The flange 12 rests on the driven element 3 in the area of ​​the axial recess 13.

[0033] The driven anchor 5 is connected to the camshaft 2 via a surface-structured press fit 14. The driven anchor 5 has a surface structure 15 (or surface profile) on its radially outer side in its axial end region (facing the camshaft). In the embodiment shown, the surface structure 15 is formed by knurling with axially parallel grooves. The surface structure 15 is formed circumferentially. When the camshaft tube 16 of the camshaft 2 is joined to the axial end region of the driven anchor 5, a press fit is formed, which is reinforced by the surface structure 15. In the axial region of the press fit 14, a sensor wheel 17 is arranged on the radial outer side of the camshaft tube 16, which reinforces the press fit 14.

[0034] Reference Signs List

[0035] 1 Camshaft adjuster

[0036] 2 camshafts

[0037] 3 Driven elements

[0038] 4 Drive components

[0039] 5 Driven anchor

[0040] 6. Connection

[0041] 7. First Section

[0042] 8 Second Section

[0043] 9 Contact surface

[0044] 10 Contact surface

[0045] 11 hydraulic channels

[0046] 12 flange

[0047] 13 Axial recess

[0048] 14 Press-fit portion

[0049] 15 Surface structure

[0050] 16 Camshaft tube

[0051] 17 sensor wheel

Claims

1. A camshaft adjuster (1) for adjusting the phase position of a camshaft (2) relative to a crankshaft in a motor vehicle drivetrain, the camshaft adjuster (1) comprising: a driven element (3) which is designed to rotate relative to a drive element (4) of the camshaft adjuster (1) within a limited angular range; and a driven anchor (5) of shaft-shaped design which is intended to connect the driven element (3) to the camshaft (2) in a rotationally fixed manner, wherein the driven element (3) and the driven anchor (5) are connected to each other via a force-fitting and / or material-fitting connection (6), characterized in that The connecting portion (6) has at least one first section (7) with a higher surface roughness and at least one second section (8) with a lower surface roughness, the first section and the second section being adjacent to each other in the circumferential direction, the camshaft adjuster (1) being constructed as a vane-type camshaft adjuster, and having a hydraulic channel (11) in the driven element (3) and / or the driven anchor (5) for adjusting the driven element (3) relative to the drive element (4), wherein the hydraulic channel (11) is arranged in the region of the second section (8) of the connecting portion (6).

2. The camshaft adjuster (1) according to claim 1, characterized in that The connecting portion (6) has a plurality of first sections (7) with higher surface roughness and a plurality of second sections (8) with lower surface roughness alternating in a circumferential direction.

3. The camshaft adjuster (1) according to claim 2, characterized in that The first section (7) is formed by a surface structure that is interrupted in the circumferential direction.

4. The camshaft adjuster (1) according to claim 2 or 3, characterized in that The second section (8) is designed as a radial bearing surface for centrally supporting the driven anchor (5) on the driven element (3).

5. The camshaft adjuster (1) according to any one of claims 1 to 3, characterized in that The contact surface (9) of the driven element (3) has a smaller inner diameter in the region of the second section (8) than in the region of the first section (7).

6. The camshaft adjuster (1) according to any one of claims 1 to 3, characterized in that The contact surface (10) of the driven anchor (5) has a larger outer diameter in the region of the second section (8) than in the region of the first section (7).

7. The camshaft adjuster (1) according to any one of claims 1 to 3, characterized in that The driven anchor (5) has a radially outwardly projecting flange (12) in an axial end region of the driven anchor (5), the flange adjoining the first section (7) in the axial direction.

8. The camshaft adjuster (1) according to any one of claims 1 to 3, characterized in that The camshaft adjuster (1) has a drive element (4) which is arranged concentrically with the driven element (3) and radially outside the driven element (3), wherein the driven element (3) is mounted rotatably relative to the drive element (4) within a limited angular range.

9. A camshaft adjuster arrangement comprising a camshaft adjuster (1) according to any one of claims 1 to 8 and a camshaft (2) connected in a rotationally fixed manner to the driven anchor (5) via a surface-structured press fit (14).

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