WO2005024262A1

WO2005024262A1 - Automatic reduction of the distance between the ends of a device for transferring a pressure force

Info

Publication number: WO2005024262A1
Application number: PCT/NO2004/000266
Authority: WO
Inventors: Morten Berger Gunnerud; Inge André H. JOHANSEN
Original assignee: Kongsberg Automotive As
Priority date: 2003-09-09
Filing date: 2004-09-09
Publication date: 2005-03-17
Also published as: SE526654C2; SE0302414D0; SE0302414L

Abstract

An apparatus for automatic reduction of the distance between the ends of a device for transferring a pressure force under a stroke of the device in a pressure direction (P). The apparatus comprises a housing (35), input mechanism (1) that is designed to execute an input stroke in relation to housing (35) over an input stroke-range (S1) in the pressure direction under execution of the pressure force, and an output mechanism (20) that is designed to execute an output stroke corresponding to the input stroke over an output stroke-range (S2). Input mechanism (1) is connected to twopawls (10,11) and can cause the engagement of the pawl with a row of teeth (22,23) associated with output mechanism (20). If the output stroke-range (S2) is displaced towards the input stroke area the pawl comes into contact with the teeth of the teeth row that its nearest the input stroke area such that it will not be correspondingly displaced. A device comprising the apparatus.

Description

Automatic reduction of the distance between the ends of a device for transferring a pressure force

The invention relates to an apparatus for the automatic reduction of the distance between the ends of a device for transferring a pressure force during a stroke of the device in the pressure direction, as specified in the ingress to claim 1.

The invention further relates to a device according to claim 4, for transferring.of pressure forces from a clutch pedal to a release bearing of a vehicle clutch, where a pressure force that is exercised by the clutch pedal results in a release of the clutch.

With a manual clutch for a vehicle, the clutch is used by the vehicle's driver by the exercise of a force against an input mechanism such as a pedal, that originates in a start position, and that after a certain movement resulting from the exercise of the force reaches an end position. This results in a corresponding movement of an output mechanism, such as a release bearing, for disengagement of the clutch. When the force is no longer applied against the pedal, a return device such as a return spring moves it back to the start position. The pedal is thereby caused to execute a back-and-forth movement or a stroke over a stroke-range between the start-and end positions. The input mechanism and the output mechanism can thereby execute an input stroke and an output stroke respectively.

It is most comfortable for the driver if the pedal's start position and the stroke-range remain unchanged.

For the sake of reliability, it is preferable that the pedal is attached to the release bearing via a mechanical device. A mechanical connection is further preferable to a hydraulic connection, because there is no danger for fluid leakage in that hydraulic fluid can be damaging to the environment.

A clutch release bearing is referred to as "pulling" if, during use of the pedal, a pulling force is exercised against the release bearing or its lever. With increased wear of the discs of a clutch having such an operating mechanism, the start position of the release bearing will be gradually changed in such a manner that the start position becomes further away from the end position, which can result in the clutch being more or less continuously disengaged even without any movement of the pedal, which is disadvantageous. In order to maintain the start position, it is known from, for example, GB2210946, GB518300, GB2300455 , and US4304322 that the rod of the mechanism can be lengthened automatically.

For clutches with a pressing release bearing, where there is exercised a pressure force against the release bearing or its lever under use of the pedal, a corresponding shortening of for example the rod of the mechanism must be employed, but at the present the rod is shortened manually, something which is time-consuming and costly.

Similarly, it can also be the case for similar mechanical rod devices that are used with other apparatuses than clutches, and where it is also desirable to maintain the length and position of the input mechanism's stroke range.

The object of the invention is to provide an apparatus and a device of the type previously identified, which does not have the above-identified disadvantages.

The characteristic features of the device according to the invention are set forth in the characterizing features of the attached claims.

The invention will be described in further detail with reference to the drawings that show an embodiment of an apparatus according to the invention.

Fig 1 shows a longitudinal section through an apparatus according to the invention.

Fig 2 shows a longitudinal section through the left end portion of the apparatus for the shown in fig 1, wherein sections have been scored away.

Fig 3 shows a longitudinal section through a clutch actuator having an apparatus according to the invention.

The expressions "left" and "up" shall be understood as the direction towards the left of the figures from the perspective of the reader, with respect to the edge of the drawings sheet directed away from the reader.

Fig 1 shows a general stroke device 100 having an input mechanism 1 that has a longitudinal axis 2, and that is arranged to execute an iput stroke in its longitudinal direction, in that input mechanism 1 can execute a pressure stroke in the direction of arrow P and a return stroke in the opposite direction. The stroke runs over a predefined input stroke-range S I . A first return body 25 such as a screw spring can be connected to input mechanism 1 that continuously attempts to move input mechanism 1 towards the left in fig 1.

Input mechanism 1 can have a pin 3 that runs across longitudinal axis 2 and into the left end of an axial groove or passage 4, that is arranged in a left hand side, narrow end portion or first end area 5 of a guide member 6, that runs coaxially with input mechanism 1. Guide member 6 has a right hand side, expanded end portion or second end area 7 with an axial passage or bore 8 with an opening 9 directed towards the right of the figure. At the left end of bore 8 there is hinged to guide member 6 and symmetrically around longitudinal axis 2 two pawls 10, 1 1 in such a manner that pawls 10, 1 1 can swing in the plane that runs radially in relation to guide member 6. It should be understood that there may be employed only one pawls or more than two pawls. The free ends of the pawls are directed towards the bore's opening 9 and are formed as an essentially radially, outwardly projecting tooth 12,13. Around the two pawls 10,1 1 can be arranged an eleastic element such as a spring 14, that seeks to pull pawls 10,1 1 radially inward.

A portion of an output mechanism 20 is arranged in bore 8 such that it can slide axially in bore 8. This portion of output mechanism 20 has a central recess 21 with an opening directed towards the left in fig 1, and radially outside of each pawl 9, output mechanism 20 has an axially running row of teeth 22,23 that are directed radially inwards towards recess 21. The free end sections of the pawls are positioned in recess 21. When pawls 10,11 are influenced solely by spring 14, then spring 14 can pull pawls 10,1 1 to a position where they are located radially within teeth 22,23 and are not engaging therewith.

In the position as shown in fig 1 , output mechanism 20 is in a start position and is arranged to execute a pressure stroke over a stroke-range S2 from the start position to an end position. A second return body 26 such as a screw spring, seeks to move output mechanism 20 towards the left in fig 1.

A press rod 30 is arranged in groove 4 of guide member 6 that can slide axially in groove 4. Press rod 30 has a first end or contact end 31 that is arranged in contact against pin 3 of input mechanism 1 , and a second end or working end 32. Working end 32 is pointed and faces in the right hand direction, and can be formed for example as a wedge, pyramid, cone or the like.

When press rod 30 is influenced by a pressure force and moved towards the right, it's working end 32 can be moved in between pawls 10, 1 1, whereby these will be moved radially outwards.

When press rod 30 is not influenced by such a pressure force, it can be pressed in the opposite direction by the action of spring 14 pressing pawls 10,1 1 radially inwards against working end 32, in that a component of the force provided by spring 14 is directed axially towards the left. Working end 32 and/or the pawls radially inwardly directed surfaces can be supplied with a lubricant or be coated by material that has good lubricating characteristics. Between guide member 6 and output mechanism 20 is arranged an elastic suspension element or spring 34 that together with return body 26 seeks to bring these components into a predetermined respective position.

As shown in fig 2, pin 3 can run in a channel 16 of the narrow end of guide member 6, which provides a clearance C or limited respective axial movement of input mechanism 1 and guide member 6.

The guide member can be mounted in a housing 35.

The operation of the apparatus shall be described below, wherein the apparatus's components have an original relative position that is shown in fig 1. In this position there is equilibrium between spring 34 and return body 26.

If a pressure force is first exerted towards the right against input mechanism 1 , then the input mechanism's pin 3 will first be brought against the contact end 31 of press rod 30, such that press rod 30 will be moved to the right in a length corresponding to clearance C. Thereby will the press rod's working end 32 be brought against the radial inner surface of pawls 10,1 1 and cause a swinging of pawls 10,1 1 radially outward until pawl's teeth 12,13 engage the respective teeth 22,23 of output mechanism 20. With a first movement of input mechanism 1 , the pressure force that is exerted by input mechanism 1 will be transferred to output mechanism 20, and input mechanism 1 and output mechanism 20 will be moved to their respective end positions.

When the pressure force against input mechanism 1 is no longer being exerted, then the second return body 26 causes a movement of input mechanism 1 towards the left via teeth 12, 13, 22, 23 and press rod 30.

When output mechanism 20 thereafter reaches its start position, there will be a new balance between return body 26 and spring 34, such that there ceases to be exerted a force towards the left against output mechanism 20. Thereby will the output mechanism's teeth 22,23 no longer exert an axial force against pawl's teeth 12, 13, nor will there be any friction forces between these components, such that spring 14 can easily move pawls 10,1 1 radially inward and out of engagement with the output mechanism's teeth 22, 23.

With a new exertion of a pressure force against input mechanism 1 , the above- described cycle can be repeated.

In the event it should occur that the start position for the output mechanism has been displaced towards the left after the output mechanism 20 under the previous cycle has been pressed towards the right, then output mechanism 20 can press guide member 6 against a stopper 36 of housing 35. Thereafter, input mechanism 1 can be moved further towards the left corresponding to clearance C under influence of a return body 25, together with the horizontal force component exerted by pawls 10,1 1. Spring 14 can thereby cause a swinging of pawls 10,1 1 radially inwards, such that its teeth 12,13 no longer engage the teeth 22,23 of the output mechanism. Since a force will still be exerted towards the left against output mechanism 20, output mechanism 20 will be further moved to the left without any hindrance by pawls 10,1 1 and by exceeding the force of spring 34, until a new start position is achieved for output mechanism 20 which has an equilibrium between the force exerted by spring 34 and the second return body 26.

With a new exertion of a pressure force against input mechanism 1 , the pawl's teeth 10,1 1 can be brought into engagement with teeth 22,23 of output mechanism 20 that are located closer to the bottom of recess 21 , that is, there has been a reduction of the distance between input mechanism 1 and output mechanism 20, that is, between the ends of device 100.

Fig 3 shows a use of the apparatus according to the invention, whereby it is used with a device for operating a clutch 62 of a vehicle (not shown), where the apparatus's output mechanism 20 is connected with a rod 61 or the like arranged to influenced the clutch's release bearing 60.

According to this figure, housing 35 of the apparatus is formed as a cylinder portion of a servo actuator for the clutch 62 and the apparatus's guide member 6 is formed as a piston element that can slide sealingly and axially in the cylinder portion. Housing 35 and guide member 6 define a cylinder chamber 40 that is sealed by a gasket 41 and 42 that is arranged between housing 35 and the narrow end portion 5 and the expanded portion 7 of guide member 6 respectively.

Furthermore, a first end portion 45 of a lever 46 is articulately connected with a clutch pedal 47 of a vehicle via a first swivel 48, a middle section 49 of lever 46 is movably connected with the apparatus's guide member 6 via a second swivel 50 and a second end portion 51 of lever 46 is articulately connected via a third swivel 54 with an end portion of an elongated, axially-movable valve body 52 of a servo valve 53 for regulating a flow of pressure fluid, for example pressurized air, to and from cylinder chamber 40. Servo valve 53 can be supplied with pressurized air via an injection opening 56 and returning pressurized air from cylinder chamber 40 can be diverted via an exhaust opening 55.

A return spring 57 is arranged to continuously seek to bring clutch pedal 47 back to a start position, where it will remain when it is not influenced by the driver of the vehicle. By depressing clutch pedal 47, middle section 49 can be swung in a clockwise direction about either the second or the third swivel 50 or 54 respectively.

The method of operation for this device shall be described below, based upon the relative position of the device's components as shown in fig 3 and wherein the reference numerals for the device's components are the same as from fig 1 and 2.

If the driver presses clutch pedal 47, then lever 46 will swing around the third swivel 54, wherein valve body 52 exerts an appropriate counterforce against being moved towards the left of the figure. Thereby will press rod 30 be moved towards the right, such that teeth 12,13 of pawls 10,1 1 engage teeth 22,23 of output mechanism 20. In order to move the press rod further towards the right resulting in a disengagement of the clutch, an increased force is needed.

With a following complete depression of the clutch pedal, middle section 49 will swing around the second swivel 50, whereby the third swivel 54 will be moved towards the left taking with it valve body 52. In this manner, pressurized air can flow from the injection opening 56 to cylinder chamber 40 via passages in valve 53 and move guide member 6 as well as output mechanism 20 towards the right to operate the clutch's release bearing 60 and disengagement of the clutch 62.

After the shifting of a gear has been performed, clutch pedal 47 will be moved back, whereby lever 46 can swing around the second swivel 50 in a counterclockwise direction. Thereby will the third swivel 54 and valve body 52 be moved towards the right, such that cylinder chamber 40 can communicate with exhaust opening 55 via an appropriate passage in valve 53 and pressurized air in cylinder chamber 40 can be released to the outside air. In this manner, guide member 6 and press rod 30 can be moved towards the left and lever 46 can swing counterclockwise around the third swivel 54. The pawl's teeth 12,13 can thereby be brought out of engagement with teeth 22,23 of the output mechanism and lever 46 can be brought to its original position prior to operation of the clutch pedal, that is, the position shown in fig 3.

Even though the description above is for a clutch device that comprises the device according to the invention, and where the device is formed as a servo device, it should be understood that such a servo device can be used with other types of apparatus.

Claims

CLAIMS 1. An apparatus for automatic reduction of the distance between the ends of a device for transferring a pressure force under a stroke of the device in a pressure direction (P), where the apparatus comprises -a housing (35), - an input mechanism(l) that is arranged to execute an input stroke in relation to housing (35) over an input stroke-range (S I) in the pressure direction during exertion of the pressure force, and -an output mechanism (20) that is arranged to execute an output stroke corresponding to the input stroke in the pressure direction over an output stroke- range (S2), and whereby - input mechanism (1) and output mechanism (20) after such stroke are arranged to execute respective return strokes in a return direction in the opposite direction of the pressure direction (P), characterized in that the apparatus (100) comprises -a press rod (30) that can be moved and runs in the stroke direction, and that has a first end (31) arranged against the input mechanism and a second end section (32), -a guide member (6) that runs in the pressure direction, and that has a first end area (5) for axial guidance/insertion of press rod (30), and a second end area (7), to which is hinged at least one pawl (10,1 1), that under axial movement of press rod (30) in the pressure direction (P) can come into contact with press rod's (30) second end section (32) and of this be swung radially outward, and that under the following movement of press rod (30) in the return direction can be swung radially inward, -an output mechanism(20) that has a row of teeth (22,23) that runs in the pressure direction (P), and that can be brought into engagement with the pawl (10,11) when the pawl (10,1 1) is swung radially outward, and -an elastic element (34) that is arranged between guide member (6) and output mechanism (20), and that continuously seeks to move output mechanism (20) to a predetermined position in relation to guide member (6).

2. An apparatus according to claim 1 , characterized in that in guide member's (6) first end area (5) is arranged an axially running, oblong groove or passage (16), in which there is slidably inserted a crosswise pin (3) of input mechanism (1), the length of which corresponds to the axial movement of press rod (30) between a first position, wherein pres rod's (30) second end section does not cause pawls (10,1 1) to engage with the teeth (22,23) of guide member (6), and a second position, wherein press rod's (30) second end section does close such an engagement.

3. The apparatus according to claim 1 or 2, characterized in that the second end section (32) of press rod (30) is formed as a wedge, pyramid, cone or the like that is pointed and faces in the direction away from the first end section (31) of press rod (30).

4. A device for transferring a pressure force from a clutch pedal (47) to a release bearing (60) of a vehicle clutch (62), where pressure force that is exerted against the clutch pedal causes a disengagement of the clutch, characterized in that the device comprises an apparatus (100) according to the preceding claims.

5. The device according to claim 4, characterized in that housing (35), guide member (6) and output mechanism (20) are formed as a cylinder element, a piston element and a piston rod of a pressure fluid cylinder respectively, wherein input mechanism (1,46) are further arranged for operating a pressure fluid valve for supplying a pressure fluid to the servo cylinder.