WO2009123463A1

WO2009123463A1 - Torque block

Info

Publication number: WO2009123463A1
Application number: PCT/NO2009/000101
Authority: WO
Inventors: Harald Borgen
Original assignee: Techni As
Priority date: 2008-03-19
Filing date: 2009-03-17
Publication date: 2009-10-08
Also published as: NO20081441L; NO329207B1

Abstract

The primary function of the invention is to operate as a constant torque block up to a given holding torque. If the torque of the shaft exceeds the holding torque of the invention the shaft can be rotated. The holding torque operates in both rotational directions for shaft.

Description

Torque Block

The present invention regards a new type of torque block with constant torque momentum.

The background for the invention is the requirement for a blocking torque for gears for use in valve actuators where a valve is equipped with a spring securing a closing function. This spring force will be transmitted through an actuator to a moment of rotation to be held back (blocked) in order to position the valve. The valves are normally operated using an ROV (remote operated vehicle) which is only able to adjust valves using a moment of rotation. The blocking function for the valve will therefore have to be part of the mechanism for adjustment.

In accordance with the present invention this is achieved by a device as disclosed in claim 1 having the characterizing features as disclosed in the characterizing part of the claim.

The invention will be described in more detail below with references to the drawings where figure 1 shows the geometry of the invention in an exploded top-down perspective, figure 2 shows a return block cross- sectioned through a cut in the middle. The blocking momentum is achieved by using rolling resistance in axial needle bearings 6 that are alternatingly connected towards the shaft 2 and housing 9 in such a way that some of the bearing friction from a plurality of bearings contribute to the total moment. The release 3 operated in that the momentum is only activated on changing direction of rotation. The release is an additional function which is not essential for the invention. The limited momentum is between the shaft 2 and external housing 9 which is statically locked in further geometry. Technically speaking the torque block is a torque reducer for torsion momentum transferred in shaft 2, and torque limiter for torque transferred to external housing 9 as shown in figure 1. For the application the invention is a torque block since shaft 2 can only be rotated if the momentum exceeds the holding momentum of the sum of the bearing frictions.

The main function of the invention is to operate as a constant torque block up to a certain holding torque. If the torque in the shaft 2 exceeds the holding torque of the invention the shaft will be able to rotate. The holding torque operates in both rotational directions for shaft 2. Of the types of existing torque blocks with release are normally constructed in such a way to operate with a holding torque designed to handle the entire load (torque) at full load. In addition these have the possibility of release at low load. One example of this is release for outboard engines for boat engines and clutches for cars. A blocking torque for these transmissions is normally based on a metal cone or clutch segments tightened axially by the transmitted torque. A distinguishing feature from the invention is that these technical solutions are not suited for holding a slipping torque/constant torque over a longer period of time. Contact surfaces on cone or segments will then degenerate and degenerate the holding function. The invention is designed in order to operate with a constant torque over an operating period exceeding all known technical solutions. Since the blocking function is designed with friction from axial needle bearing or bearings a lifetime of the needle bearings will be dimensioned for the lifetime.

In a typical embodiment of the invention in an application the specific function will be:

1. One external torque to be locked/held is connected to a shaft 1.

2. Said torque is transferred to the shaft 2 through a release 3. Said release will operate in that it locks (rigidly connected) on rotating one way, and releases opposite way. 3. If shaft 1 and shaft 2 are connected in that the release is in lock the torque will operate to rotate the shaft 2.

4. Shaft 2 is connected to axial needle bearing with discs locked to shaft using wedge tracks.

5. The side of axial needle bearing 6 not connected to shaft 2 is connected to external housing 9 using discs that are locked to wedge tracks in housing 9.

6. Axial needle bearings are pretensioned using dish spring 4 which are pretensioned using tightening nuts 8.

7. When shaft 2 is rotating the bearings connected to shaft 2 and external housing 9 through discs will exert a torque on to shaft 2. Thus shaft 1 will be connected to housing with a constant blocking torque equal to the sum of bearing frictions.

8. The total torque can partly be adjusted by varying the pretensioned force in the dish springs. The number of bearings is primarily dimensioned for torque with capacity (force).

Claims

P a t e n t C l a i m s

L A device for providing a constant blocking torque characterized in that said torque operating on shaft (2) is transferred to external housing (9) through bearing friction in axial needle bearings (6), said needle bearings being alternatingly connected to shaft (2) with springs locked to shaft (5) and discs locked to housing (7), said friction being achieved by providing a pre-tensioning force axially operating a cross all needle bearings with dish springs (4) that are tightened with tightening nut (9).

2. The device according to claim 1, characterized in that a release function operating in that torque limitation only operates at a particularly rotation direction as indicated by release (3).

3. The device according to claim 1, characterized in a gear so that the blocking torque is built into said gear and operates as a constant blocking torque in order to secure locking function for rotation at an external operating torque provided onto the gear, to be blocked.

4. The device according to claim 1, characterized in a gear so that the blocking torque is built into said gear and operates as a constant blocking torque in order to secure locking function for rotation transferred through a ball screw, said ball screw actuating an axial force operating on an external device to be axially positioned.

5. The device according to claim 1, characterized in a gear so that the blocking torque is built into said gear and operates as a constant blocking torque in order to secure locking function for rotation transmitted through a ball screw, said ball screw actuating an axial force positioning an opening for a valve.