Device for controlling the operation of a ventilator, which can be driven by a hydraulic motor, of a cooling device

Patent metadata

Field	Value
Publication number	US-2015308325-A1
Application number	US-201314649599-A
Country	US
Kind code	A1
Filing date	Nov 9, 2013
Priority date	Dec 5, 2012
Publication date	Oct 29, 2015
Grant date	—

Abstract

Disclosed is a device for controlling the operation of a ventilator, which can be driven by a hydraulic motor ( 1 ), of a cooling device, in particular in a working appliance for agricultural use, wherein the hydraulic motor ( 1 ) can be supplied with pressure fluid by means of a hydraulic pump ( 3 ) via a valve arrangement ( 7 ) than can be set to a first valve position for operation of the hydraulic motor ( 1 ) in a first direction of rotation and to a second valve position for operation of the hydraulic motor ( 1 ) in a second direction of rotation, a control device ( 21 ) being present, by means of which the valve arrangement ( 7 ) can be set to an intermediate position which reduces the pressure supply to the hydraulic motor ( 1 ) during transitions between the first and second valve positions for a time period that allows the ventilator speed to be reduced.

First claim

1 . A device for controlling the operation of a ventilator, which can be driven by a hydraulic motor ( 1 ), of a cooling device, in particular in working machinery for agricultural use, wherein the hydraulic motor ( 1 ) can be supplied with pressure fluid by means of a hydraulic pump ( 3 ) via a valve arrangement ( 7 ) than can be set to a first valve position for operation of the hydraulic motor (I) in a first direction of rotation and to a second valve position for operation of the hydraulic motor (I) in a second direction of rotation, a control device ( 21 ) being present by means of which the valve arrangement ( 7 ) can be set to an intermediate position which reduces the pressure supply to the hydraulic motor ( 1 ) during transitions between the first and second valve positions for a time period that allows for a reduction of the ventilator speed.

2 . The device according to claim 1 , characterized in that the valve arrangement ( 7 ) has a valve housing ( 27 ) with at least one control spool ( 29 ) which can move longitudinally therein to control connection positions ( 27 ) in the valve housing in the form of at least
two working connections (A, B), one pressure or supply connection or pump connection, as well as one tank connection (Ti, T2).

3 . The device according to claim 1 , characterized in that the control spool ( 29 ) is acted upon by control forces on its opposing sides, wherein fluid pressure originating from the control device ( 21 ) impinges on one side ( 49 ), and spring pressure from a spring arrangement ( 17 ) having at least one compression spring ( 51 , 53 ) impinges on the opposing side.

4 . The device according to claim 1 , characterized in that the control device ( 21 ) has a directional spool valve, preferably a 3/2 directional valve, that is connected at the input side to the preferably adjustable hydraulic pump ( 3 ), and at the output side to the associated side ( 49 ) of the control spool ( 29 ) of the valve arrangement ( 7 ).

5 . The device according to claim 1 , characterized in that the spring pressure can be exerted on the control spool ( 29 ) by two compression springs ( 51 , 53 ) preferably arranged concentric to each other which preferably possess spring stiffnesses that differ from each other, and are adapted to pressure level stages of the fluid pressures originating from the control device ( 21 ) such that, at one pressure level stage, the valve arrangement ( 7 ) passes from the first valve position to the second intermediate position, and at the additional pressure level stage, from the intermediate position to the second valve position.

6 . The device according to claim 1 , characterized in that the control spool ( 29 ) forms step surfaces ( 55 , 57 ) which are offset from each other at the end facing the pressures springs ( 51 , 53 ), and a first compression spring ( 51 ) acts on the outermost step surface ( 55 ) such that the control spool ( 29 ) can be moved into the intermediate position against the force of the first compression spring ( 51 ) upon moving out of the first valve position, and the control spool ( 29 ), upon moving out of the intermediate position into the second valve position, also interacts with the inner second compression spring ( 52 ) by means of the inner second step surface ( 57 ) such that the control spool can move against the force of both compression springs ( 51 , 53 ) into the second valve position.

7 . The device according to claim 1 , characterized in that the second compression spring ( 53 ) coaxially surrounds the first compression spring ( 51 ) and is braced against a slide ring ( 59 ) which is on the end facing the control spool ( 29 ) and is fixed in a retaining position against axial movement in the direction towards the control spool ( 29 ), and which is abutted by the inner, second step surface ( 57 ) of the control spool ( 29 ) in the intermediate position, and the slide ring ( 59 ) moves axially against the force of the second compression spring ( 53 ) during the movement into the second valve position.

8 . The device according to claim 1 , characterized in that the control spool ( 29 ) has three steps ( 33 , 35 , 37 ) in the form of radial elevations which run along on the valve housing ( 27 ) and which form control edges ( 39 , 41 , 43 , 45 ) that interact in a controlling manner with the housing connections, and a first fluid chamber ( 50 ) is formed between a first step ( 33 ) on the end ( 49 ) subject to fluid pressure by the control device ( 21 ) and the middle step ( 35 ), and a second fluid chamber ( 52 ) is formed between the middle step ( 35 ) and the third step ( 37 ) at the end facing the compression springs ( 51 , 53 ).

9 . The device according to claim 1 , characterized in that, in the first valve position, the fluid connection between the working connection (B) and tank connection (T1) is formed via the first fluid chamber ( 50 ), and the fluid connection between the pressure connection (P) and the working connection (A) is formed via the second fluid chamber ( 52 ).

10 . The device according to claim 1 , characterized in that the control edges ( 41 , 43 ) of the middle step ( 35 ) are provided with a bevel ( 47 ), and the middle step ( 35 ) is aligned with the pressure connection (P) when the control spool ( 29 ) is in the intermediate position such that a throttled fluid connection between the pressure connection (P) and the working connections (B and A) via the first ( 50 ) and second fluid chamber ( 52 ) is formed by the bevels ( 47 ), and the fluid connection between working connection (B) and tank connection (T1) via the first fluid chamber ( 50 ) is released in the intermediate position, and the fluid connection between the working connection (A) and tank connection (T2) via the second fluid chamber ( 52 ) is released.

11 . A device according to claim 1 , characterized in that in the second valve position, the fluid connection between the pressure connection (P) and working connection (B) via the first fluid compartment ( 50 ), and between the working connection (A) and the tank connection (T2) via the second fluid compartment ( 52 ), are released.

12 . The device according to claim 1 , characterized in that a leakage line ( 25 ) is provided, and leakage connections (D and Dp) are provided on the valve housing ( 27 ) of the valve arrangement ( 7 ), and an inlet-side connection ( 23 ) is provided on the valve of the control device ( 21 ) which is connected to the leakage line ( 25 ).

13 . The device according to claim 1 , characterized in that the variable pump ( 3 ) can be adjusted to a low pressure level corresponding to the intermediate position of the valve arrangement ( 7 ) starting from the operating pressure provided to operate the hydraulic motor (I) in order to introduce transitions between the first and second valve position, the lower pressure causing the 3/2 directional valve of the control device ( 21 ) of the valve arrangement ( 7 ) to adjust the control spool ( 29 ) to the intermediate position, to decrease the speed of the hydraulic motor ( 1 ), wherein after a time sufficient for the decrease in speed, the variable pump ( 3 ) can be turned up to the operating pressure level, and a directional valve for the control device ( 21 ) can be locked for the transition from the intermediate position to the first or second valve position, or can be moved into the released state to supply the operating pressure level to the valve arrangement ( 7 ).

Assignees

• Hydac Fluidtechnik Gmbh

Inventors

• Baer Harald
• Schaefer Josef Christian

Classifications

• F01P7/044 Primary

  using hydraulic drives · CPC title

• F01P5/043 Primary

  Pump reversing arrangements · CPC title

• F16H61/4069

  Valves related to the control of neutral, e.g. shut off valves · CPC title

• F16H61/4061

  Control related to directional control valves, e.g. change-over valves, for crossing the feeding conduits · CPC title

• B60K2025/026

  by a hydraulic transmission · CPC title