Swashplate holddown and adjustable centering mechanism

A technology of swash plate and fixing device, which is applied in variable displacement engines, liquid variable displacement machinery, reciprocating piston engines, etc., and can solve problems such as shortening the life of springs

CN100422507CInactive Publication Date: 2008-10-01EATON CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2008-10-01
Estimated Expiration
Not applicable · inactive patent

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Abstract

A swashplate centering and holddown mechanism for an axial piston unit comprising a cylinder barrel disposed for rotation about an axis of rotation. A cam member is tiltable about a transverse axis and has a swashplate. The swashplate is perpendicular to the axis of rotation, in a neutral position, and has a displaced position. The swashplate centering and holddown mechanism biases the cam member axially toward a cradle surface and pivotably toward the neutral position. The mechanism comprises a pair of arms, each of which defines a pivot location, at one axial end thereof, fixed relative to a pump housing on one side of the axis of rotation, and a swashplate-engaging portion, at the opposite axial end thereof, engaging the swashplate, on the other side of said axis of rotation, when said swashplate is in neutral. A connector is operably associated with the arms, whereby the arms are able to pivot about the pivot locations in a generally scissors-type movement. A pair of springs biases the swashplate-engaging portions of the arms toward the swashplate, whereby, in the absence of an input to tilt the cam member, the swashplate is in engagement with both of said swashplate-engaging portions and is in the neutral position.
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Description

technical field

[0001] The present invention relates to a variable displacement hydraulic pump comprising a rotary assembly, a tiltable cam member and a swash plate for varying the displacement of the rotary assembly, and in particular to a rotary pump for such a pump Swash plate centering and fixing device (mechanism). More specifically, the invention relates to a device whose centering portion is adjustable.

[0002] Although hydraulic pumps to which the present invention is applied may include various types of rotary assemblies, the present invention is particularly advantageous when used in "in-line" axial piston type pump rotary assemblies, namely, rotary assemblies that include A rotating cylinder barrel defines a plurality of cylinders, each cylinder having a reciprocating piston therein, wherein the cylinders are parallel to each other and to an axis of rotation of an input shaft. Accordingly, the present invention will be described below in connection with such an i...

Examples

Embodiment Construction

[0019] Referring now to the drawings, which are not intended to limit the invention, there is shown in Figure 1, generally designated 11, a variable displacement axial piston pump to which the invention may be applied. The pump 11 comprises two main parts: a pump element 13 and a hydraulically actuated servo 15 . It should be understood that the invention is not required to use the particular type of pump element 13 shown here, nor does it require a hydraulic type of servo to actuate the pump 11 .

[0020] The pump element 13 includes a pump housing 19 defining an internal cavity or chamber 21 . As known to those skilled in the art, an input shaft 23 extends from the left end in FIG. 1 into cavity 21 (see FIG. 2 ), and then extends through an opening in a port housing 25 to the right end. The port housing 25 is also sometimes referred to as a back plate or end cap. Hereinafter and in the appended claims, the term "housing" may refer to and include both the pump housing 19 an...