GB2475845A - Method and device for measuring the elongation of a chain - Google Patents
Method and device for measuring the elongation of a chain Download PDFInfo
- Publication number
- GB2475845A GB2475845A GB0921031A GB0921031A GB2475845A GB 2475845 A GB2475845 A GB 2475845A GB 0921031 A GB0921031 A GB 0921031A GB 0921031 A GB0921031 A GB 0921031A GB 2475845 A GB2475845 A GB 2475845A
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 230000005540 biological transmission Effects 0.000 claims abstract description 10
- 238000004590 computer program Methods 0.000 claims description 12
- 230000008093 supporting effect Effects 0.000 claims description 11
- 230000000903 blocking effect Effects 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 5
- 239000000306 component Substances 0.000 claims 6
- 230000006870 function Effects 0.000 description 6
- 238000002485 combustion reaction Methods 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 230000001151 other effect Effects 0.000 description 3
- 230000001020 rhythmical effect Effects 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 2
- 239000011324 bead Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 229940036310 program Drugs 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
- G01M13/02—Gearings; Transmission mechanisms
- G01M13/023—Power-transmitting endless elements, e.g. belts or chains
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
Abstract
A method for measuring the elongation of a chain 11 belonging to a chain gearing 10 of a vehicle, wherein the chain transmission comprises at least: a first rotating shaft 13 having first reference means 130 placed on it, first stationary means 150 for cooperating with the first reference means 130 when the latter is in a predetermined angular position. A second rotating shaft 12 includes second reference means 120 placed on it, and second stationary means 140 for cooperating with the second reference means 120, when the latter is in a predetermined angular position; wherein the chain 11 is provided for connecting the first and second rotating shafts 13, 12, so that the first reference means 130 is expected to be in a given angular position when the second reference means 120 is in the angular position in which they cooperate with the second stationary means 140. The method comprises the operational steps of: determining the actual angular position of the first reference means 130 when the second reference means 120 is in the angular position in which they cooperate with the second stationary means 140; determining the deviation between the actual angular position and the expected one; and calculating the chain elongation as a function of the deviation between the actual position with the expected position.
Description
METH) AND DEVICE FOR CHAIN TI 4EASURING
TECHNICAL FID
The present invention generally relates to a method and to a device for measuring the elongation of a chain belonging to a chain gearing of a vehicle, in particular the elongation of the engine valve train chain.
BA
Valve train is an all-encompassing term used to describe the mecha- nisms and parts which control the operation of the valves of an in-ternal combustion engine.
A valve train generally comprises a plurality of valves, rocker arms, pushrods, springs, and a camshaft which controls the timing for valve opening and closing.
The camshaft is driven by the crankshaft, though a transmission chain which takes the name of valve train chain.
The valve train chain may become elongated, for example due to rhyth-mical stresses caused by the cams or the springs of the valves, or due to other effects that may take place during use of the vehicle.
This elongation has a first negative effect in that the driver and the passengers of the combustion engine vehicle perceive noise.
Moreover if, during the use of the vehicle, such elongation becomes excessive, valves may impact upon the respective piston causing seri- ous damage to the engine that may even lead to the necessity of en-gine replacement.
In real life situations, in order to have a measure of the valve train chain elongation, it is necessary to bring the vehicle in a re-pair garage and, due to the position of the chain, the engine must usually be pulled out from the vehicle, leading to lengthy and costly operations.
S.M'WJRY An object of the present invention is to enable the measurement of a chain elongation without pulling out the engine, to thereby allowing preventive actions to be adopted.
Another object of the invention is to provide a monitoring of the chain elongation without using complex devices and taking advantage from the computational capabilities of the Electronic Control Unit (ECU) of the vehicle.
A further object is to provide the driver with an alert signal in case the chain elongation is excessive.
Another object of the present invention is to meet these goals by means of a rational and inexpensive solution.
These and other objects are attained by the characteristics of the invention as reported in the independent claims. The dependent claims delineate preferred and/or especially advantageous aspects of the in-vention.
The invention is generally based on the remark that both the camshaft and Lhe crankshaft are generally associated to one or more auxiliary systems that uses eccentric reference means integral with the shaft, and stationary means arranged for cooperating with said reference means, when the latter are in a predetermined angular posi-tion.
Auxiliary systems of this kind are for example the blocking systems that are provided for blocking the camshaft and the crankshaft during the valve train chain assembling, or the measuring systems that are associated to the camshaft and the crankshaft for monitoring their angular speed.
In fact, a blocking system generally comprises a slot in the shaft, which is arranged for aligning with a passing hole in the shaft car- rier, in order to receive a pin that blocks the shaft in a predeter-mined angular position.
A measuring systems generally comprises a stationary sensor that is activated by an eccentric element placed on the shaft, in order to generate an electric signal when said eccentric element aligns with the sensor itself.
In both cases, since the camshaft and the crankshaft are synchronized by the train valve chain, the angular position of the camshaft refer- ence means, namely the camshaft slot or the camshaft eccentric ele-ment, is always correlated to the angular position of the crankshaft reference means, namely the crankshaft slot or the crankshaft eccen-tric element, and vice versa.
Therefore, while the crankshaft reference means are in the angular position in which they coopeiate with the correspondent stationary means, namely the crankshaft carrier hole or the crankshaft sensor, the camshaft reference means can be expected to be in a predetermined angular position.
If however the valve train chain become elongated, the camshaft ref-erence means will be generally delayed with respect to said expected angular position.
Starting from these remarks, the invention generally provides a me-thod for measuring the elongation of a chain belonging to a chain gearing of a vehicle, wherein the chain gearing comprises at least: a first rotating shaft having first reference means placed on it, first stationary means for cooperating with said first reference means, when the latter are in a predetermined angular position, a second ro-tating shaft having second reference means placed on it, and second stationary means for cooperating with said second reference means, when the latter are in a predetermined angular position; and wherein the chain is provided for cinematically connecting said first and second rotating shafts, so that the first reference means are ex-pected to be in a predetermined angular position, when the second reference means are in the angular position in which they cooperate with the second stationary means.
The measuring method according to the invention comprises the opera-tional steps of: -determining the actual angular position of the first reference means, when the second reference means are in the angular position in which they coopeiate wlLh the second stationary means, -determining the deviation between said actual angular position and the expected one, and -calculating the chain elongation in function of said devia-tion.
As a matter of fact, if the actual angular position of the first ref-erence means coincide with the expected one, it means that the chain is not elongated.
If conversely the actual angular position of the first reference means does not coincide with the expected one, it means that the chain is elongated.
This elongation is geometrical related and thus proportional to the deviation between the actual angular position of the first reference means and the expected one.
Therefore, through the determination of said deviation, it is effec-tively possible to calculate the elongation of the chain, without pulling the engine out from the vehicle.
According to a preferred aspect of the invention, the method provides for periodically repeating the above mentioned operational steps, in order to keep the chain elongation monitored.
According to another aspect of the invention, the method further comprises the operational steps of setting a chain elongation thre-shold, and performing a protection action, if the calculated chain elongation exceeds said threshold.
Preferably, said protection action provides for generating an alert rul According to an embodiment of the invention, the first statio- nary means comprise a first position sensor that generates an elec-trical signal when the first reference means are in a predetermined position; and. the second stationary means comprise a second position sensor that generates an electrical signal when the second reference means are in a predetermined position.
As a matter of fact, each position sensor can be a sensor belonging to a conventional speed measuring system.
In this contest, the determination of the actual position of the first reference means, is achieved by the determination of the time period between the electrical signal generated by the first position sensor and the electrical signal generated by the second position sensor.
Thank to these sensors, the chain elongation can be measured at any time by the Engine Control Unit (ECU), without using any other device and without shutting off the internal combustion engine.
According to another embodiment of the invention, the first ref- erence means comprise a slot in the first shaft, and the first sta-tionary means comprise a hole in a first shaft carrier, which aligns with said first shaft slot when the latter is in a predetermined an-gular position; likewise, the second reference means comprise a slot in the second shaft, and the second stationary means comprise a hole in a second shaft carrier, which aligns with said second shaft slot when the latter is in a predetermined angular position.
According to this embodiment, the chain gearing is further arranged so that the first shaft slot is expected to align with the first shaft carrier hole, substantially at the same time in which the second shaft slot aligns with the second shaft carrier hole.
In other words, when the second shaft slot is aligned with the second shaft carrier hole, the angular position of the first shaft slot is expected to coincide with the position of the first shaft carrier hole.
It follows that the eventual deviation between the actual position of the first shaft slot and the expected, corresponds to the mutual po- sition between the first shaft slot itself and the first shaft carri-er hole.
In this contest, the method according the present embodiment provides for blocking the second shaft by inserting a pin in its slot through the second shaft carrier hole.
While the second shaft is blocked, the determination of the actual angular position of the first shaft slot, the determination of the deviation between the actual position and the expected one, and the calculation of the chain elongation, are performed by engaging a spe-cial device in the first shaft carrier hole.
Said special device is an object of the present invention, and gener-ally comprises: -a stationary component adapted to be applied to the first shaft carrier, -a rotating component coupled to said stationary component, and -converting means for correlating the chain elongation to the angular position of the rotating component with respect to the sta-tionary component.
According to the invention, the rotating component comprises at least a supporting portion adapted to be coaxially inserted in the first shaft carrier hole, and an eccentric nose that projects from an end of said supporting portion, in order to be accorrmodate into the first shaft slot.
In use, the rotating component is rotated with respect to the statio-nary portion.
If the eccentric nose is completely free to rotate within the slot, it means that the slot is alianed with the carrier hole, and there-fore that the chain is not elongated.
If conversely the rotation is limited by the eccentric nose that hurts against a lateral face of the slot, it means that the latter is not aligned with the hole.
The rotation done by the rotating component, until the eccentric nose hurts against the lateral face of the slot, is proportional to the displacement between the slot and hole, and thus to the chain elonga-tion.
Therefore, the converting means can be effectively calibrated for providing the chain elongation.
According to a preferred embodiment of the invention, the sup-porting portion of the device has cylindrical shape.
According to an aspect of the invention, the eccentric nose of the device is laterally contained within the diameter of said cylin-drical supporting portion.
According to another aspect of the invention, the cylindrical supporting portion has the same diameter of the second shaft carrier hole.
According to another aspect of the invention, the converting means of the device comprise an angular reference, and a scale which correlates the angular position of said angular reference to the chain elongation. Preferably, the angular reference is placed on the rotating component of the device, and the scale is placed on the sta-tionary component.
The method according to an embodiment of the invention can be realized in the form of a computer program comprising a program-code to carry out all the steps of the method of the invention and in the form of a computer program product comprising means for executing the computer program.
The computer program product comprises, according to a preferred em- bodirnent of the invention, a control apparatus for an internal corn- bustion engine, for example the ECU of the engine, in which the pro-gram is stored so that the control apparatus defines the invention in the same way as the method. In this case, when the control apparatus execute the computer program all the steps of the method according to the invention are carried out.
The method according to the invention can be also realized in the form of an electromagnetic signal, said signal being modulated to carry a sequence of data bits which represent a computer program to carry out all steps of the method of the invention.
BRIEF DESCRIPTI1 OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: -figures 1 represents a chain gearing of the invention in which the chain is not elongated; -figures 2 represents the chain gearing of figure 1 in which the chain is elongated; -figure 3 is a lateral view of a device used for measuring the chain elongation according to a first eithodiment of the invention; -figures 4 and 5 are first-angle projections of the device of figure 3; -figure 6 is a lateral exploded view of the device of figure 3; -figure 7 is the section Vu-Vu indicated in figure 4; -figures 8 and 9 are the view indicated with the arrow VIII in fig-ure 2, shown in two subsequent phase during the use of the device of figure 3; -figure 10 represents a chain gearing of the invention in a configu-ration in which the chain is not elongated; -figure bA illustrates in a timelines the electrical signal gener-ated by the crankshaft position sensors shown in figure 10; -figure lOB illustrates in a timelines the electrical signal gener-ated by the camshaft position sensors shown in figure 10; -figure 11 represents a chain gearing of the invention in a configu-ration in which the chain is elongated; -figure hA illustrates in a timelines the electrical signal gener-ated by the crankshaft position sensors shown in figure 11; -figure llB illustrates in a tirnelines the electrical signal gener-ated by the camshaft position sensors shown in figure 11.
DESCRIPTI OF ThE PRERED 1BCDIMENT A first embodiment of the present invention is now described with reference to the chain transmission 10 that is shown in figures land2.
The chain transmission 10 comprises a valve train chain 11 that de- rives its movement from a crankshaft 12 in order to operate a cam-shaft 13.
The crankshaft 12 is supported and partially enclosed within a con-ventional crankcase 14, which is only partially and scherrtically shown in the figures.
The camshaft 13 is supported and enclosed within a conventional cy-under head 15, which is only partially and schematically shown in the figures.
In order to allow the assembling of the valve train chain 11, both the crankshaft 12 and the camshaft 13 are generally provided with a slot in their lateral surfaces, which are respectively indi-cated with 120 and 130.
The crankshaft slot 120 is provided for aligning with a passing hole 140 of the crankcase 14, in order to receive a pin 16 that blocks the crankshaft 12 in a predetermined angular position.
The width of the crankshaft slot 120 is substantially equal to the diameter of the crankcase hole 140.
The camshaft slot 130 is provided for aligning with a passing hole 150 of the cylinder head 15, in order to receive another pin (not shown) that blocks the camshaft 13 in a predetermined angular posi-tion.
The width of the camshaft slot 130 is substantially equal to the di-ameter of the cylinder head hole 150.
While both the crankshaft 12 and the camshaft 13 are blocked by their respective pins, the valve train chain 11 is wrapped around them to thereby realizing their cinematic connection.
The blocking pins are then removed and the chain transmission 10 is ready for operating.
In this way, while the valve train chain 11 is not elongated, the camshaft slot 130 is always expected to align with the cylinder head hole 150, substantially in the same instant in which the crankshaft slot 120 aligns with the crankshaft hole 140, as illustrated in fig-ure 1.
If conversely the valve train chain 11 become elongated, for example due to rhythmical stresses caused by the cams or the springs of the valves, or due to other effects that may take place during use of the vehicle, the camshaft slot 130 is expected to align with the cylinder head hole 150 late in time with respect to the instant in which the crankshaft slot 120 aligns with the crankshaft hole 140, as illus-trated in figure 2.
The first embodiment of the present invention provides a method for measuring the valve train chain elongation, which is based on the preceding considerations.
The method firstly provides for blocking the crankshaft 120 in the angular position in which the slot 120 is aligned with the crankshaft hole 140.
This action is performed by rotating carefully the crankshaft 12 (through conventional means that are not shown), until the slot 120 aligns with the hole 140, and then engaging the blocking pin 16 with them.
While the crankshaft 12 is blocked, the method provides for determin-ing the angular position of the camshaft hole 130.
If the camshaft slot 130 is aligned with the cylinder head hole 150, it means that the valve train chain 11 is not elongated (see fig. 1).
If conversely the camshaft slot 130 is not aligned with the cylinder head hole 150, it means that the chain is elongated (see fig.2).
This elongation is geometrical related and thus proportional to the deviation between the actual angular position of the camshaft slot 130 and the position of the cylinder head hole 150.
Therefore, the method provides for determining said deviation, and for calculating the valve train chain elongation in function of the deviation itself.
In the present example, the steps of determining the position of the camshaft slot 130, of determining the position deviation with respect to the cylinder head hole 150, and of calculating the chain elonga- tion in function of said deviation, are perfonTled by means of a spe-cial measuring device 17.
As shown in figures 3 to 7, the special measuring device 17 comprises two components, including a stationary component 170, and a rotating component 171 that is inserted in a passing hole 172 of the statio-nary component 170, in order to freely rotate around a longitudinal axis X of said hole 172.
The stationary component 170 is shaped as a bush having a threaded shank 173 and an enlarged head 174, both coaxial with the central passing hole 172.
In use, the threaded shank 173 is provided for screwing into a threaded enlarged mouth 151 of the cylinder head hole 150, in order to fix the stationary component 170 of the device 17 to the cylinder head 15, in a configuration in which the passing hole 172 is coaxial with the cylinder head hole 150.
The rotating component 171 of the device 17 comprises a cylindrical portion 175 that is coaxially inserted in the passing hole 172 of the stationary component 170, and an enlarged head 176 that is supported against the enlarged head 174, in order to axially constrain the ro-tatirig component 171 with respect to the stationary component 170, in a configuration in which the cylindrical portion 175 projects from the opposite side of the passing hole 172.
The diameter of the cylindrical portion 175 corresponds to the diame- ter of the passing hole 172, which in turn corresponds to the diame-ter of the cylinder head hole 150.
The rotating component 171 further comprises an eccentric nose 177 protruding from the free end of the cylindrical portion 175.
The eccentric nose 177 has a cylindrical shape, having a longitudinal axis Y that is para]lel to the axis of the cylindrical portion 175 and thus to the axis X of the passing hole 172, and diameter that is smaller than that of the cylindrical portion 175.
As shown in figure 4, the eccentric nose 177 is contained within the outline of the cylindrical portion 175, and its lateral surface is tangent to the lateral surface of the latter.
In use, the projecting segment of the cylindrical portion 175 is pro-vided for exactly inserting in the cylinder head hole 150, so that the eccentric nose 177 can be accommodated into the camshaft slot 130.
When the eccentric nose 177 is accommodated into the camshaft slot 130, the rotating component 171 of the device 17 is manually rotated with respect to the stationary component 170, by means of the en-larged head 176.
If the eccentric nose 177 is completely free to rotate within the camshaft slot 130, it means that the camshaft slot 130 is aligned with the cylinder head hole 150, and therefore that the valve train chain 11 is not elongated.
If conversely the rotation of the rotating part 171 is limited by the eccentric nose 177 that hurts against a lateral face of the camshaft slot 130, it means that the latter is not aligned with the cylinder head hole 150 (see figure 8 and 9) and therefore that the valve train chain 11 is elongated.
The rotation, done by the rotating component 171 from an initial po-sition (fig.8) until the eccentric nose 177 hurts against the lateral face of the slot 130 (fig.9), is in qeometrical relation and thus proportional to the deviation between the position of the slot 130 and the position of the hole 150, which in turn is in geometrical re-lation and thus proportional to the valve train chain elongation.
Accordingly, the measuring device 17 is further provided with cali-brated converting means, which directly correlates the valve train chain elongation to the angular position of the rotating component 171 with respect to the stationary component 170, when the eccentric nose 177 hurts against the lateral face of the camshaft slot 130.
In the present example, the converting means comprise an angular ref-erence 178, which is located on the enlarged head 176 of the rotating component 171, and a calibrated scale 179 correlating the position of said angular reference 178 to the valve train chain elongation, which is located on the enlarged head of the stationary component 170.
Obviously, the measuring method according to the present ernbodi-ment requires to shut off the internal combustion engine, but can be effectively perfonned without pulling the engine out from the ve-hicle.
The method can be periodically repeated, in order to keep the valve train chain elongation monitored.
In particular, the method provides for setting a valve train chain elongation threshold, and for recorrmending the driver to replace the valve train chain with a new one, if the elongation exceeds said threshold.
A second embodiment of the present invention is now described with reference to the chain transmission 10 that is shown in figures and 11.
As before, the chain transmission 10 comprises a valve train chain 11 that derives its movement from a crankshaft 12 in order to operate a camshaft 13.
In order to monitor the angular speed of the crankshaft 12, the latter is provided with an eccentric element 121, which is arranged for aligning with a stationary sensor 141 once per crankshaft rota-tion, as shown in figure 10.
When the eccentric element 121 is aligned with the sensor 141, the latter is activated for generating an electric signal A, represented in figure bA, which is sent and elaborated by the Engine Control Unit (ECU) of the vehicle.
Analogously, in order to monitoring the angular speed of the camshaft 13, the latter is provided with an eccentric element 131, which is arranged for aligning with a stationary sensor 152 once per camshaft rotation, as shown in figure 10.
When the eccentric element 131 is aligned with the sensor 152, the latter is activated for generating an electric signal B, represented in figure lOB, which is sent and elaborated by the Engine Control Unit (ECU) of the vehicle.
In the present example, the chain transmission 10 is arranged so that, while the valve train chain 11 is not elongated, the electric signal B generated by the sensor 152 is always expected to be syn-chronised in time with the electric signal A generated by the sensor 141, as illustrated in figires 1OA and lOB.
If conversely the valve train chain 11 become elongated, for example due to rhythmical stresses caused by the cams or the springs of the valves, or due to other effects that may take place during use of the vehicle, the electric signal B generated by the sensor 152 is ex-pected to be late in time with respect to electric signal A generated by the sensor 141, as illustrated in figures hA and llB.
The second embodiment of the present invention provides a method for measuring the valve train chain elongation, which is based on the preceding considerations.
As a matter of fact, the method firstly provides for determining the actual angular position of the camshaft eccentric element 131, when crankshaft eccentric element 121 aligns with the respective sensor 141.
This angular position is determined by measuring the time interval T between the instant in which the sensor 141 generates the electric signal A, and the instant in which the sensor 152 generates the elec-tric signal B. In the present example, if the time interval T is substantially zero, it means that the camshaft eccentric element 131 was aligned with the sensor 152, and that the valve train chain 11 is not elongated (see fig. 10) If conversely the time interval T is not zero, it means that the cam-shaft eccentric element 131 was not aligned with the sensor 152, and that the valve train chain 11 is elongated (see fig.ll).
As a matter of fact, the entity of the time interval T is proportion-al to the camshaft angular speed, and to the deviation that there was between the actual angular position of the camshaft eccentric element 131 and the sensor 152, at the time in which the sensor 142 generated the electric signal A. This deviation is in turns proportional to the valve train chain elongation.
Therefore, the method generally provides for: -determining the time interval T, -determining the angular speed of the camshaft 13, -calculating the deviation that there was between the angular position of the camshaft eccentric element 131 and the sensor 152, in function of the time interval T and the camshaft angular speed, and then -calculating the valve train chain elongation in function of said deviation.
Obviously, the calculation of the valve train chain elongation can be performed directly in function of the time interval T and the cam-shaft angular speed, through an equation in which the calculation of the angular deviation is integrated.
Since the method involves the use of sensors, it can be inte- grally performed by the ECU, without using any other device and with-out shutting off the internal combustion engine.
This method can be frequently and easily repeated by the ECU, in or-der to keep the valve train chain elongation monitored.
Preferably, the method further provides for setting in the ECU a chain elongation threshold, and for the ECU to generate an alert sig- nal, if the measured valve train chain elongation exceeds said thre-shold.
In particular, this alert signal can recorrmend the driver to replace the valve train chain with a new one.
While the present invention has been described with respect to cer- tain preferred embodiments and particular applications, it is unders-tood that the description set forth herein above is to be taken by way of example and not of limitation. Those skilled in the art will recognize various modifications to the particular embodiments are within the scope of the appended claims. Therefore, it is intended that the invention not be limited to the disclosed embodiments, but that it has the full scope permitted by the language of the following claims.
Key to the Drawings REFERENCE NtJMB Chain transmission 11 Valve train chain 12 Crankshaft 13 Camshaft 14 Crankcase Cylinder head 16 Pin 17 asuring device Slot in crankshaft 121 Eccentric elnt Slot in camshaft 131 Eccentric elnt 140 Hole in crankcase 141 Stationary sensor Hole in cylinder bead 151 Enlarged mouth of 150 152 Stationary sensor 170 Stationary caxonent of 17 171 Rotating cxxronent 172 Passing hole 173 Threaded shank 174 Enlarged head 175 Cylindrical portion 176 Enlarged head 177 Eccentric nose 178 Angular reference 179 Calibrated scale X Longitudinal axis of 172 Y Longitudinal axis of 177 A Electric signal B Electric signal T Time interval c1n4S
Claims (15)
1. Method for measuring the elongation of a chain (11) belonging to a chain gearing (10) of a vehicle, wherein the chain transmission comprises at least: a first rotating shaft (13) having first reference means (130, 131) placed on it, first stationary means (150, 152) for cooperating with said first reference means (130, 131), when the latter are in a predetermined angular position, a second rotating shaft (12) having second refer-ence means (120, 121) placed on it, and second stationary means (140, 141) for cooperating with said second reference means (120, 121), when the latter are in a predetermined angular position, and wherein said chain (11) is provided for cinematically connecting said first and second rotating shafts (13, 12), so that the first reference means (130, 131) are expected to be in a given angular p0-sition when the second reference means (120, 121) are in the angular position in which they cooperate with the second stationary means (140, 141), characterized in that the method comprises the operational steps of: -determining the actual angular position of the first reference means (130, 131), when the second reference means (120, 121) are in the angular position in which they cooperate with the second statio-nary means (140, 141), -determining the deviation between said actual angular position arid the expected one, and -calculating the chain elongation in function of said deviation comparing said actual position with the expected one.
2. Method according to claim 1, characterized in that the method provides for repeating said operational steps in order to keep the chain elongation monitored.
3. Method according to claim 1 characterized in that the method further comprises the operational steps of: setting a chain elongation threshold, and performing a protection action if the calculated chain elonga-tion exceeds said threshold.
4. Method according to claim 3, characterized in that the protection action provides for generating an alert signal.Method according to claim 1, characterized in that the first statio-nary means comprise a first position sensor (152) that generates an electrical signal when the first reference means (131) are in a pre-determined position; in that the second stationary means comprise a second position sensor (141) that generates an electrical signal when the second reference means (121) are in a predetermined position; and in that the operational step of determining the actual position of the first reference means (131), provides for determining the time period between the electrical signal generated by the first position sensor (152) and the electrical signal generated by the second posi-tion sensor (141).
5. Method according to claim 1, characterized in that the first ref-erence means comprise a slot (130) in the first shaft (13), and the first stationary means comprise a hole (150) in a first shaft carrier (15), which aligns with said first shaft slot (130) when the latter is in a predetermined angular position; in that the second reference means comprise a slot (120) in the second shaft (12), and the second stationary means comprise a hole (140) in a second shaft carrier (14), which aligns with said second shaft slot (120) when the latter is in a predetermined angular position; in that the chain gearing (10) is arranged so that the first shaft slot (130) is expected to align with the first shaft carrier hole (150), substantially at the same time in which the second shaft slot (120) aligns with the second shaft carrier (140); and in that the method provides for performing the operational steps after blocking the second rotating shaft (12) by inserting a pin (16) in the second shaft slot (120) through the second shaft carrier hole (140).
6. Method according to claim 5, characterized in that the method provides the operational steps to be performed by engaging a device (17) in the first shaft carrier hole (150).
7. Device for measuring the elongation of a chain (11) belonging to a chain gearing (10) of a vehicle, characterized in that the device comprises: -a stationary component (170), -a rotating component (171) coupled to said stationary compo-nent, and -converting means (178, 179) for correlating the chain elonga- tion to the angular position of the rotating component (171) with re-spect to the stationary component (170), wherein the rotating component (171) comprises a supporting portion (175) and an eccentric nose (177) projecting from an end of said sup-porting portion (175).
8. Device according to claim 7, characterized in that the supporting portion (175) has a cylindrical shape.
9. Device according to claim 8, characterized in that the eccentric nose (177) is laterally contained within the diameter of the cylin-drical supporting portion (175).
10. Device according to claim 8, characterized in that the cylindric-al supporting portion (175) has the same diameter of a hole (150) of a chain gearing shaft carrier (15), in which said cylindrical sup-porting portion (175) has to be inserted for the device to measuring the chain elongation.
11. Device according to claim 7, characterized in that the converting means (178, 179) comprise an angular reference (178) and a scale (179) which correlates the angular position of said angular reference (178) to the chain elongation.
12. Computer program comprising a computer-code for carrying out a method according to claim 1.
13. Computer program product comprising a computer program according to claim 12.
14. Computer program product as in claim 13, comprising a control ap-paratus wherein the computer program is stored.
15. An electromagnetic signal modulated as a carrier for a sequence of data bits representing the computer program according to claim 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0921031A GB2475845A (en) | 2009-12-01 | 2009-12-01 | Method and device for measuring the elongation of a chain |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0921031A GB2475845A (en) | 2009-12-01 | 2009-12-01 | Method and device for measuring the elongation of a chain |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0921031D0 GB0921031D0 (en) | 2010-01-13 |
| GB2475845A true GB2475845A (en) | 2011-06-08 |
Family
ID=41572979
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0921031A Withdrawn GB2475845A (en) | 2009-12-01 | 2009-12-01 | Method and device for measuring the elongation of a chain |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2475845A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5689067A (en) * | 1995-02-03 | 1997-11-18 | Daimler-Benz Ag | Diagnostic method and apparatus for monitoring the wear of at least an engine timing chain |
| DE10155199A1 (en) * | 2001-11-12 | 2003-05-22 | Ina Schaeffler Kg | Wear indicator for traction devices in synchronous drives |
| GB2406844A (en) * | 2001-07-24 | 2005-04-13 | Renold Plc | Chain elongation monitoring apparatus and method |
| WO2007143830A1 (en) * | 2006-06-13 | 2007-12-21 | Litens Automotive Partnership | Improved engine flexible drive elongation measurement |
| GB2454471A (en) * | 2007-11-07 | 2009-05-13 | Sensdata Ltd | Apparatus For Monitoring The Efficiency Of A Pulley System |
| EP2085643A1 (en) * | 2006-10-31 | 2009-08-05 | JTEKT Corporation | Method and device for producing member to be wound, device for measuring circumferential length of member to be wound, and device for applying pretension |
-
2009
- 2009-12-01 GB GB0921031A patent/GB2475845A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5689067A (en) * | 1995-02-03 | 1997-11-18 | Daimler-Benz Ag | Diagnostic method and apparatus for monitoring the wear of at least an engine timing chain |
| GB2406844A (en) * | 2001-07-24 | 2005-04-13 | Renold Plc | Chain elongation monitoring apparatus and method |
| DE10155199A1 (en) * | 2001-11-12 | 2003-05-22 | Ina Schaeffler Kg | Wear indicator for traction devices in synchronous drives |
| WO2007143830A1 (en) * | 2006-06-13 | 2007-12-21 | Litens Automotive Partnership | Improved engine flexible drive elongation measurement |
| EP2085643A1 (en) * | 2006-10-31 | 2009-08-05 | JTEKT Corporation | Method and device for producing member to be wound, device for measuring circumferential length of member to be wound, and device for applying pretension |
| GB2454471A (en) * | 2007-11-07 | 2009-05-13 | Sensdata Ltd | Apparatus For Monitoring The Efficiency Of A Pulley System |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0921031D0 (en) | 2010-01-13 |
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| Date | Code | Title | Description |
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| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |