HYDRAULIC TRIM DEVICE, BOAT DRIVE AND BOAT

Abstract

A hydraulic trim device is provided for a boat motor with at least one trimming cylinder, a piston rod movable axially in the trimming cylinder between a first end position and a second end position, a trimming plate and a hydraulic unit. The trimming cylinder can be pressurized via the hydraulic unit to extend the piston rod. The piston rod has a contact portion and the trimming plate has an contact surface and the contact portion is in contact with the contact surface. The contact portion moves along the contact surface when the piston rod moves between the first end position and the second end position relative to the contact surface. The contact surface at least partially has a convex curvature in the direction of the piston rod. A boat motor with a hydraulic trim device and to a boat with such a boat motor are also provided.

Claims

1. A hydraulic trim device for a boat motor, comprising: at least one trimming cylinder; a piston rod movable axially in the trimming cylinder between a first end position and a second end position; a trimming plate; and a hydraulic unit; wherein; the trimming cylinder is pressurized via the hydraulic unit to extend the piston rod; the piston rod has a contact portion and the trimming plate has a contact surface, the contact portion being in contact with the contact surface; the contact portion moves along the contact surface during a movement of the piston rod between the first end position and the second end position relative to the contact surface; and the contact surface at least partially has a convex curvature in a direction of the piston rod.

2. The hydraulic trim device according to claim 1, wherein the contact portion is in a first contact position in the first end position of the piston rod and in a second contact position in the second end position of the piston rod, the convex curvature of the contact surface between the first contact position and the second contact position being asymmetrical.

3. The hydraulic trim device according to claim 1, wherein the piston rod has a central mid-axis, the convex curvature being such that the central mid-axis of the piston rod in any position of the piston rod between the first end position and the second end position is orthogonal on the trimming plate.

4. The hydraulic trim device according to claim 1, wherein the piston rod has a central mid-axis, the convex curvature being such that the central mid-axis of the piston rod in any position of the piston rod between the first end position and the second end position is inclined by at most 6° on the trimming plate.

5. The hydraulic trim device according to claim 4, wherein the central mid-axis of the piston rod is inclined on the trimming plate by between 1.5° and 4.5°, or by 2° to 4° and or by 3°.

6. The hydraulic trim device according to claim 4, wherein the central mid-axis of the piston rod is inclined in a direction of the first contact position.

7. The hydraulic trim device according to claim 1, wherein the contact portion is a spherical contact portion.

8. The hydraulic trim device according to claim 1, wherein the contact portion is a planar contact portion.

9. A boat motor comprising: a boat drive; and a hydraulic trim device according to claim 1; wherein the trimming plate is disposed on the boat drive.

10. A boat comprising: a hull; and a boat motor according to claim 9; wherein the boat drive is pivotably arranged on the hull by the hydraulic trim device.

11. The boat according to claim 10, wherein the boat is a sports boat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the following, the invention is explained in more detail with reference to exemplary embodiments shown in the figures. The figures show schematically:

[0020] FIG. 1 is a first side view of a boat with an outboard motor;

[0021] FIG. 2 is a second side view of the boat shown in FIG. 1;

[0022] FIG. 3 is a side view of a hydraulic trim device according to a first embodiment with a trimming cylinder and a piston rod located in a first end position;

[0023] FIG. 4 is a side view of the hydraulic trim device shown in FIG. 3 with the piston rod in an intermediate position;

[0024] FIG. 5 is a side view of the hydraulic trim device shown in FIG. 3 with the piston rod in a second end position;

[0025] FIG. 6 is a detail view of the hydraulic trim device shown in FIG. 3; and

[0026] FIG. 7 is a side view of a hydraulic trim device according to a second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0027] In FIGS. 1 and 2, a boat 101 with a boat motor 100 according to the invention is shown. In this embodiment, the boat is a recreational boat and the boat motor 100 has a boat drive in the form of an outboard motor 105. In a known manner, the outboard motor 105 comprises a propeller 104 and is pivotable on a hull 102 of the boat 101 via a joint 103 between a lowered position (see FIG. 1) and a raised position (see FIG. 2). For this purpose, the boat 101 has a hydraulic trim device 1 according to the invention as part of a combined hydraulic trim-lift device 110.

[0028] The hydraulic trim lift device 110 has a lift cylinder 106 and, in this embodiment, a trimming cylinder 2 as part of the hydraulic trim device 1. Of course, embodiments with two or more lift cylinders and with two or more trimming cylinders are also conceivable. Furthermore, a hydraulic unit (not shown in more detail) is provided, via which the lift cylinder 106 and the trimming cylinder 2 can be pressurized in a known manner.

[0029] The trimming cylinder 2 has a piston rod 3 which can be moved axially between a first end position EP1 and a second end position EP2 in the trimming cylinder 2, see also FIGS. 3 to 5. By pressurizing the trimming cylinder 2 via the hydraulic unit, the piston rod 3 is extended in the conventional manner. A contact portion 4, 4′ is provided at the axial end of the piston rod 3 facing a trimming plate 5 being disposed on the outboard motor 105. The contact portion 4, 4′ is in contact with a contact surface 6 of the trimming plate 5.

[0030] During power trimming while the boat 101 is travelling, the trimming cylinder 2 extends and the contact portion 4, 4′ of the piston rod 3 of the trimming cylinder 2 moves along the contact surface 6 of the trimming plate 5 to pivot the outboard motor 105 relative to the hull 102 along the joint 103 about the transverse axis of the boat 101 to fine-tune between the lowered position (FIG. 1) and raised position (FIG. 2). Suboptimal alignment between the hull 102 and the water surface results in a loss of propulsion due to cavitation of the propeller 104 as well as incorrect force application direction, erratic handling and increased fuel consumption.

[0031] In FIG. 3, a hydraulic trim device 1 is shown as part of a combined hydraulic trim-lift device 110 according to a first embodiment. The outboard motor 105 is not shown for clarity reasons. The state shown in FIG. 3 corresponds essentially to the state shown in FIG. 1 with the outboard motor 105 fully lowered and therefore not finely adjusted. The piston rod 3 of the trimming cylinder 2 is in the first end position EP1 and the contact portion 4 of the piston rod 3 is in a first contact position AP1 on the contact surface 6 of the trimming plate 5.

[0032] In this embodiment, the contact portion 4 of the piston rod 3 is spherical, so that there is point contact between the contact portion 4 and the contact surface 6. As shown, the contact surface 6 of the trimming plate 5 has a convex curvature in the direction of the piston rod 3 or the contact portion 4, as will be described in more detail below.

[0033] To perform a power trim, the trimming cylinder 2 is pressurized by the hydraulic unit in the conventional manner and the piston rod 3 extends. Here, the contact portion 4 of the piston rod 3 moves along the contact surface 6 of the trimming plate 5 and a force is applied to the outboard motor 105 via the trimming plate 5 so that the outboard motor 105 is moved or pivoted relative to the hull 102 via the joint 103.

[0034] FIG. 4 shows an intermediate position of the contact portion 4 of the piston rod 3 on the contact surface 6 of the trimming plate 5, and FIG. 5 shows a state essentially corresponding to the state shown in FIG. 2, which corresponds to maximum power trim. In the state shown in FIG. 5, the piston rod 3 is in the second end position EP2 and the contact portion 4 of the piston rod 3 is in a second contact position AP2 on the contact surface 6 of the trimming plate 5.

[0035] FIG. 6 shows a detail from FIG. 3, in which the contact portion 4 of the piston rod 3 is located in the first contact position AP1 on the contact surface 6 of the trimming plate 5. The piston rod 3 has a central mid-axis MA. The curvature of the contact surface 6 of the trimming plate 5 is selected such that the central mid-axis MA is always inclined by a predetermined angle α relative to the force introduction direction KE shown as a dashed arrow during movement along the contact surface 6 between the first contact position AP1 and the second contact position AP2. In this exemplary embodiment, α=3°. In other words, the piston rod 3 is not orthogonal on the contact surface 6 of the trimming plate 5, but the central mid-axis MA is inclined in the direction of the first contact position AP by the angle α=3° with respect to the force introduction direction KE. The contact surface 6 or the curvature of the contact surface 6 respectively is configured so that the angle α remains the same for all positions of the contact portion 4 relative to the contact surface 7.

[0036] If the central mid-axis MA of the piston rod 3 were completely orthogonal relative to the trimming plate 5 or contact surface 6, α=0° and MA=KE would apply. In this case, the lateral forces would be minimal due to the orthogonal force application, but a noticeable slip-stick effect could occur. It has been shown that with α≤6° and especially in the range of 1.5°≤α≤4.5° an optimum compromise between introduced transverse forces and occurrence of the slip-stick effect can be achieved.

[0037] When configuring the curvature of the contact surface 6 of the trimming plate 5, this is initially selected so that it is individually matched to the corresponding kinematics of the boat motor 100 with regard to trim or power trim. Here, it is notionally assumed that an orthogonal alignment of the central mid-axis MA of the piston rod 3 to the trimming plate 5 or contact surface 6 is always to be achieved. Subsequently, if required, the contact surface 6 of the trimming plate 5 is rotated by an angle α, the angle α being at most 6°. This results in an asymmetrical and convex curvature of the contact surface 6 of the trimming plate 5 between the first contact position AP1 and the second contact position AP2.

[0038] In FIG. 7, a hydraulic trim device 1 is shown as part of a combined hydraulic trim-lift device 110 according to a second embodiment. The second embodiment of the hydraulic trim device 1 differs from the first embodiment shown in FIGS. 3 to 6 only in the design of the contact portion 4′ of the piston rod 3.

[0039] As shown, the contact portion 4′ of the piston rod 3 in this second embodiment is designed as a flat surface. Thus, in contrast to the spherical design of the contact portion according to the first embodiment, there is a line contact between the contact portion 4′ of the piston rod 3 and the contact surface 6 of the trimming plate 5. In this embodiment, the angle α=0°. Overall, this results in lower surface pressure with minimized slip-stick effect.

LIST OF REFERENCE SIGNS

[0040] 1 hydraulic trim device [0041] 2 trimming cylinder [0042] 3 piston rod [0043] 4, 4′ contact portion [0044] 5 trimming plate [0045] 6 contact surface [0046] 100 boat motor [0047] 101 boat [0048] 102 hull [0049] 103 joint [0050] 104 propeller [0051] 105 boat drive [0052] 106 lift cylinder [0053] 110 hydraulic trim-lift device [0054] AP1 first contact position [0055] AP2 second contact position [0056] EP1 first end position [0057] EP2 second end position [0058] KE force introduction direction [0059] MA central mid-axis [0060] α angle