CN112414602A - Device and method for measuring collision impact acting force and acting time - Google Patents

Abstract

The invention discloses a device and a method for measuring collision impact acting force and acting time, wherein the device comprises a balance table, a balance table bracket, a hanging weight, a vertical line and a collision block; the right side of the balance table is provided with a vertical through hole, and the left side of the balance table is provided with a hanging screw hole; suspension screw rods are distributed on the suspension screw holes; a supporting shaft is arranged at the upper part of the balance table bracket; the device also comprises a wire switch device and an oscilloscope, wherein the top of the wire switch device is provided with two exposed wire ends; the hanging weights are made of conductive materials and can be movably distributed on the exposed wire ends; the two exposed wire ends are connected with the power supply-resistance module and the oscilloscope, and the hanging weights are communicated with the two exposed wire ends to form a loop. The invention has the advantages of accurate and convenient detection, good use effect and the like.

Description

Device and method for measuring collision impact acting force and acting time

Technical Field

The invention relates to the technical field of automobile tests, in particular to a device and a method for measuring collision impact acting force and acting time.

Background

When the automobile runs on a road at a high speed and tires collide with pits, bosses, stones, steps and the like on the road, an instant impact acting force is generated on relevant parts on an engine, such as a machine body, a cylinder cover, a piston and the like. The parts moving at high speed in the engine, such as a valve chain mechanism, a camshaft, a crankshaft and the like, can also generate instantaneous impact acting force in the moving process. The action time of the part on the automobile and the engine is subjected to the instant impact action force and the action time thereof is very short (the actually measured rigid collision action time is about a few milliseconds), so that the measurement and the research are difficult. In practical engineering application, a rocker arm shaft bolt of a four-valve engine often breaks and fails, and analysis shows that overlarge impact force is one of the main reasons. The rocker shaft bolt is used for fixing the rocker shaft, the rocker shaft is a cylindrical shaft, the two sides of the rocker shaft are provided with rocker arms, the middle of the rocker shaft bolt is fastened by the rocker arm shaft bolt, and the rocker arms can swing by taking the axis of the rocker shaft as the center. The front end of the rocker arm is contacted with the valve bridge, and the valve bridge is contacted with the valve; the rear end of the rocker arm is in contact with the push rod, the push rod is in contact with the tappet, the tappet is in contact with the cam shaft bump and is driven by the cam shaft bump, and when the engine works, particularly works at a high rotating speed, the front end of the rocker arm is driven by the cam shaft bump to collide with the valve bridge and the rear end of the rocker arm is in high-speed collision with the push rod, so that collision impact acting force is generated.

Research shows that the combustion impact action stress can be amplified and propagated along a valve in the form of stress waves and can be emitted after reaching a valve bridge, and the valve bridge can be bounced with certain momentum to collide with a rocker arm and generate acting force under certain conditions. When the automobile passes through an uneven road surface (a road surface with pits, bosses, large stones and the like) at high speed, the generated collision impact can be transmitted to an engine valve chain, so that the front end of the rocker arm collides with a valve bridge and a valve or the rear end of the rocker arm collides with a push rod and a tappet violently, and therefore large impact acting force can be generated. The impact acting force generated in the above condition can be superposed under a certain condition, so that the rocker shaft supporting the rocker arm is stressed too much, and finally the bolt of the rocker shaft is broken. The size and the action time of the impact force of the collision can be tested by a special mechanical vibration test bed in the prior art, but various high-precision devices are required, such as an impact loading device, a high strain rate dynamic strain measuring device, a displacement measuring device, a photoelectric speed measuring device, a matched data acquisition and analysis device and the like.

The above background disclosure is only for the purpose of assisting understanding of the concept and technical solution of the present invention and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.

Disclosure of Invention

The invention provides a device and a method for measuring collision impact acting force and acting time of an engine rocker arm after being impacted aiming at the technical problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

a collision impact acting force and acting time measuring device comprises a balance table, a balance table bracket, a hanging weight, a vertical line and a collision block; the right side of the balance table is provided with a vertical through hole, and the left side of the balance table is provided with a hanging screw hole; suspension screw rods are distributed on the suspension screw holes; a supporting shaft is arranged at the upper part of the balance table bracket; the lower plate surface of the balance table is provided with a plurality of strip-shaped grooves corresponding to the support shaft; the balance tables can be movably distributed on the supporting shaft through the strip-shaped grooves; the hanging weights are detachably combined at the lower end of the hanging screw rod through screw rod grooves; the upper end of the vertical line is fixed on a building and distributed through the vertical through hole; the lower end of the vertical line is in a straightening state by hanging a heavy object or connecting a floor; the middle part of the collision block is provided with a vertical line through hole, and the collision block penetrates through the vertical line and is distributed above the balance table;

the device also comprises a wire switch device and an oscilloscope, wherein the top of the wire switch device is provided with two exposed wire ends; the hanging weights are made of conductive materials and can be movably distributed on the exposed wire ends; the two exposed wire ends are connected with the power supply-resistance module and the oscilloscope, and the hanging weights are communicated with the two exposed wire ends to form a loop.

Furthermore, the collision block device also comprises vertical graduated scales, wherein the vertical graduated scales are correspondingly distributed on one side of the collision block, and alignment marked lines are arranged on the collision block.

Further, still include the plummet, the plummet hangs in the lower extreme of perpendicular line.

Furthermore, the right side of the balance table is also provided with a collision table, the middle part of the collision table corresponds to the vertical through hole, is provided with a through hole and is correspondingly combined above the vertical through hole.

Further, the material of the balance table is the same as that of the engine rocker arm to be researched.

Further, the structure of the collision table is the same as the shape of the collision part of the engine rocker arm to be researched, namely the front end or the rear end of the engine rocker arm.

The method for testing by adopting the device for measuring the impact acting force and the acting time comprises the following steps:

(1) selecting a balance table with a corresponding model according to the model of an engine rocker arm to be researched, and enabling the distance between the center of the vertical through hole and the center of the suspension screw hole to be the same as the distance between the front end collision center and the rear end collision center of the engine rocker arm to be researched;

(2) selecting the collision block made of the same material and the same mass according to the research objects, namely an engine valve bridge and a valve or a push rod and a tappet;

(3) correspondingly adjusting the support shafts to be distributed on the corresponding strip-shaped grooves according to the left-right proportion of a rocker shaft for supporting the rocker arm of the engine to be researched, so that the left-right proportion of the balance table corresponds to the proportion;

(4) after the measuring device is installed as required, when the collision block does not act on the balance table, the balance table is in a horizontal state, and the bottom of the suspended weight is in contact with the two exposed wire ends, so that the oscilloscope is ensured to display normally;

(5) assuming that the front end of an object to be researched is collided by a part with mass m and velocity v, selecting a collision block with mass m, and enabling the collision block to vertically fall along the vertical line at a position with height H of v2/2g away from a collision table, wherein the velocity is just v when the collision block collides with the collision table according to a free-fall formula;

(6) observing the waveform of the oscilloscope circuit, if the oscilloscope displays that the current waveform is not disconnected, the weight is overweight, the hanging weight with the same height and lighter weight is needed to be used for re-measurement, and the hanging weight with the current just disconnected is marked as a standard hanging weight after collision is found;

if the oscilloscope displays that the current waveform is disconnected, the fact that the hanging weight which is possibly selected is too light is indicated, the hanging weight which is slightly heavier and has the same height needs to be used for re-measurement, the hanging weight which is not disconnected in current is marked as the hanging weight to be determined after the collision is found, then the hanging weight which is slightly heavier than the hanging weight to be determined is used for re-measurement, and the hanging weight which is just disconnected in current after the collision is found is marked as the standard hanging weight;

(7) recording the mass M of the standard suspended weight which can just cut off the current after collision, and considering that the equivalent acting force generated at the other end of the object to be researched is F1 ═ Mg after one end of the object to be researched is collided;

(8) setting the distance from the center of the suspended weight to the fulcrum of the balancing table as L1, and the distance from the center of the collision table to the fulcrum of the balancing table as L2; if the equivalent force of the collision platform after receiving collision impact is F2, F1L1 is F2L2, that is, F2 is F1L1/L2 is Mg L1/L2 according to the lever principle; the resultant force F applied to the fulcrum is F1+ F2 is Mg + Mg L1/L2, which is the equivalent acting force of the fastening bolt to be studied after the part with mass m and speed v is collided and impacted;

(9) the rigid collision can be regarded as momentum conservation, the collision block freely falls from the position with the height H, and rebounds to the height H after colliding with the collision table, the height H is observed and recorded through the vertical graduated scale or is shot and recorded by a high-speed camera and is compared with the vertical graduated scale for measurement, the velocity v when rebounding is equal to (2gh)1/2, the acting time of the collision block colliding with the collision table is t, and then the law of momentum conservation is followed: mv-mv trans-F2 t, giving a collision action time t-m (v-v trans)/F2-m ((2gH)1/2- (2gH)1/2)/(Mg L1/L2).

Compared with the prior art, the invention has the beneficial effects that: the device disclosed by the invention is simple in structure and ingenious in design, adopts the plumb bob and the plumb line for guiding and realizing elastic limiting, combines the balance table bracket, the oscilloscope and the adjustable weight switch assembly, and can achieve the beneficial effects of accurate and rapid detection and low cost.

Drawings

Fig. 1 is a schematic structural view of the present invention.

Detailed Description

As shown in figure 1, a collision impact force and action time measuring device comprises a balance table 4, a balance table bracket 1, a hanging weight 18, a vertical line 9 and a collision block 12; the right side of the balance table 4 is provided with a vertical through hole 7, and the left side of the balance table is provided with a hanging screw hole 4-1; suspension screw rods 14 are distributed on the suspension screw holes; certainly, the vertical through hole 7 is a small hole formed, and is mainly used for preventing the inclination of the balance table 4 from being too large after the balance table 4 is collided and inclined, the hole diameter of the vertical through hole is matched with the diameter of the vertical line 9, the vertical through hole can not be too small as long as the hanging weight 18 is not interfered to just bounce off the two exposed wire ends 17, and the hanging weight 18 is not interfered to just bounce off the two exposed wire ends 17, so that the oscilloscope 19 can accurately receive the disconnected current signal. The upper part of the balance table bracket 1 is provided with a support shaft 3, the embodiment is mainly provided with a front vertical support arm 2 and a rear vertical support arm 2, and then the support shaft 3 is combined between the two support arms 2; the lower plate surface of the balance table 4 is provided with a plurality of strip-shaped grooves 5 corresponding to the support shaft 3, and the strip-shaped grooves are used for selecting different support points to obtain the required left-right proportion during testing; the balance tables 4 can be movably distributed on the supporting shaft 3 through the strip-shaped grooves 5; the hanging weights 18 are detachably combined at the lower end of the hanging screw 14 through screw grooves 15, the hanging weights 18 are made of conductive materials, and the heights of the hanging weights 18 with the same series and different qualities are generally consistent; the upper end of the vertical line 9 is fixed on a building and distributed through the vertical through hole; the lower extreme of plumb line 9 is the state of flare-outing through hanging the heavy object or connecting the floor, and this embodiment is through being equipped with plumb bob 8, plumb bob 8 hangs the lower extreme of plumb line adopts and hangs the 8 modes of plumb bob, can effectively improve the security, prevents the excessive contact wear of plumb line 9 and vertical through-hole 7 inner chamber that the collision process probably appears. A vertical line through hole 13 is formed in the middle of the collision block and penetrates through the vertical line to be distributed above the balance table; the device also comprises a lead switch device 16 and an oscilloscope 19, wherein the top of the lead switch device is provided with two exposed lead ends 17; and the wire can be movably distributed on the exposed wire end; the two exposed wire ends are connected with the power supply-resistance module and the oscilloscope, and the hanging weights are communicated with the two exposed wire ends to form a loop. The collision block structure further comprises a vertical graduated scale 11, the vertical graduated scale 11 is correspondingly distributed on one side of the collision block, and an alignment marking line 10 is arranged on the collision block 12.

The right side of balancing stand still is equipped with collision platform 6, 6 middle parts of collision platform correspond vertical through-hole has seted up the through-hole, and corresponds the combination and be in vertical through-hole's top, this embodiment collision platform 6 can with balancing stand 4 integrated into one piece preparation or detachable assembly.

Further, the material of the balance table is the same as that of the engine rocker arm to be researched.

Further, the structure of the collision table is the same as the shape of the collision part of the engine rocker arm to be researched, namely the front end or the rear end of the engine rocker arm.

The method for testing by adopting the device for measuring the impact acting force and the acting time comprises the following steps:

(1) selecting a balance table with a corresponding model according to the model of an engine rocker arm to be researched, and enabling the distance between the center of the vertical through hole and the center of the suspension screw hole to be the same as the distance between the front end collision center and the rear end collision center of the engine rocker arm to be researched;

(2) selecting the collision block made of the same material and the same mass according to the research objects, namely an engine valve bridge and a valve or a push rod and a tappet;

(3) correspondingly adjusting the support shafts to be distributed on the corresponding strip-shaped grooves according to the left-right proportion of a rocker shaft for supporting the rocker arm of the engine to be researched, so that the left-right proportion of the balance table corresponds to the proportion;

(4) after the measuring device is installed as required, when the collision block does not act on the balance table, the balance table is in a horizontal state, and the bottom of the suspended weight is in contact with the two exposed wire ends, so that the oscilloscope is ensured to display normally;

(5) assuming that the front end of an object to be researched is collided by a part with mass m and velocity v, selecting a collision block with mass m, and enabling the collision block to vertically fall along the vertical line at a position with height H of v2/2g away from a collision table, wherein the velocity is just v when the collision block collides with the collision table according to a free-fall formula;

(6) observing the waveform of the oscilloscope circuit, if the oscilloscope displays that the current waveform is not disconnected, the weight is overweight, the hanging weight with the same height and lighter weight is needed to be used for re-measurement, and the hanging weight with the current just disconnected is marked as a standard hanging weight after collision is found;

if the oscilloscope displays that the current waveform is disconnected, the fact that the hanging weight which is possibly selected is too light is indicated, the hanging weight which is slightly heavier and has the same height needs to be used for re-measurement, the hanging weight which is not disconnected in current is marked as the hanging weight to be determined after the collision is found, then the hanging weight which is slightly heavier than the hanging weight to be determined is used for re-measurement, and the hanging weight which is just disconnected in current after the collision is found is marked as the standard hanging weight;

(7) recording the mass M of the standard suspended weight which can just cut off the current after collision, and considering that the equivalent acting force generated at the other end of the object to be researched is F1 ═ Mg after one end of the object to be researched is collided;

(8) setting the distance from the center of the suspended weight to the fulcrum of the balancing table as L1, and the distance from the center of the collision table to the fulcrum of the balancing table as L2; if the equivalent force of the collision platform after receiving collision impact is F2, F1L1 is F2L2, that is, F2 is F1L1/L2 is Mg L1/L2 according to the lever principle; the resultant force F applied to the fulcrum is F1+ F2 is Mg + Mg L1/L2, which is the equivalent acting force of the fastening bolt to be studied after the part with mass m and speed v is collided and impacted;

(9) the rigid collision can be regarded as momentum conservation, the collision block freely falls from the position with the height H, and rebounds to the height H after colliding with the collision table, the height H is observed and recorded through the vertical graduated scale or is shot and recorded by a high-speed camera and is compared with the vertical graduated scale for measurement, the velocity v when rebounding is equal to (2gh)1/2, the acting time of the collision block colliding with the collision table is t, and then the law of momentum conservation is followed: mv-mv trans-F2 t, giving a collision action time t-m (v-v trans)/F2-m ((2gH)1/2- (2gH)1/2)/(Mg L1/L2).

Claims (7)

1. The utility model provides a collision impact effort and time of action measuring device which characterized in that: the device comprises a balance table, a balance table bracket, a hanging weight, a vertical line and a collision block; the right side of the balance table is provided with a vertical through hole, and the left side of the balance table is provided with a hanging screw hole; suspension screw rods are distributed on the suspension screw holes; a supporting shaft is arranged at the upper part of the balance table bracket; the lower plate surface of the balance table is provided with a plurality of strip-shaped grooves corresponding to the support shaft; the balance tables can be movably distributed on the supporting shaft through the strip-shaped grooves; the hanging weights are detachably combined at the lower end of the hanging screw rod through screw rod grooves; the upper end of the vertical line is fixed on a building and distributed through the vertical through hole; the lower end of the vertical line is in a straightening state by hanging a heavy object or connecting a floor; the middle part of the collision block is provided with a vertical line through hole, and the collision block penetrates through the vertical line and is distributed above the balance table;

the device also comprises a wire switch device and an oscilloscope, wherein the top of the wire switch device is provided with two exposed wire ends; the hanging weights are made of conductive materials and can be movably distributed on the exposed wire ends; the two exposed wire ends are connected with the power supply-resistance module and the oscilloscope, and the hanging weights are communicated with the two exposed wire ends to form a loop.

2. The apparatus as claimed in claim 1, wherein the impact force and action time measuring device comprises: the collision block is characterized by further comprising vertical graduated scales, wherein the vertical graduated scales are correspondingly distributed on one side of the collision block, and alignment marked lines are arranged on the collision block.

3. The apparatus as claimed in claim 1, wherein the impact force and action time measuring device comprises: still include the plummet, the plummet hangs the lower extreme of plumb line.

4. The apparatus as claimed in claim 1, wherein the impact force and action time measuring device comprises: the right side of the balance table is also provided with a collision table, the middle part of the collision table corresponds to the vertical through hole and is provided with a through hole, and the collision table is correspondingly combined above the vertical through hole.

5. The apparatus as claimed in claim 1, wherein the impact force and action time measuring device comprises: the balance table is made of the same material as that of the engine rocker arm to be researched.

6. The apparatus as claimed in claim 4, wherein the impact force and action time measuring device comprises: the collision platform has the same structure as the collision part of the engine rocker arm to be researched, namely the front end or the rear end of the engine rocker arm.

7. The method for testing by using the device for measuring the impact force and action time of collision as claimed in any one of claims 1 to 6, is characterized by comprising the following steps:

(1) selecting a balance table with a corresponding model according to the model of an engine rocker arm to be researched, and enabling the distance between the center of the vertical through hole and the center of the suspension screw hole to be the same as the distance between the front end collision center and the rear end collision center of the engine rocker arm to be researched;

(2) selecting the collision block made of the same material and the same mass according to the research objects, namely an engine valve bridge and a valve or a push rod and a tappet;

(3) correspondingly adjusting the support shafts to be distributed on the corresponding strip-shaped grooves according to the left-right proportion of a rocker shaft for supporting the rocker arm of the engine to be researched, so that the left-right proportion of the balance table corresponds to the proportion;

(4) after the measuring device is installed as required, when the collision block does not act on the balance table, the balance table is in a horizontal state, and the bottom of the suspended weight is in contact with the two exposed wire ends, so that the oscilloscope is ensured to display normally;

(5) assuming that the front end of an object to be researched is collided by a part with mass m and velocity v, selecting a collision block with mass m, and enabling the collision block to vertically fall along the vertical line at a position with height H of v2/2g away from a collision table, wherein the velocity is just v when the collision block collides with the collision table according to a free-fall formula;

(6) observing the waveform of the oscilloscope circuit, if the oscilloscope displays that the current waveform is not disconnected, the weight is overweight, the hanging weight with the same height and lighter weight is needed to be used for re-measurement, and the hanging weight with the current just disconnected is marked as a standard hanging weight after collision is found;

if the oscilloscope displays that the current waveform is disconnected, the fact that the hanging weight which is possibly selected is too light is indicated, the hanging weight which is slightly heavier and has the same height needs to be used for re-measurement, the hanging weight which is not disconnected in current is marked as the hanging weight to be determined after the collision is found, then the hanging weight which is slightly heavier than the hanging weight to be determined is used for re-measurement, and the hanging weight which is just disconnected in current after the collision is found is marked as the standard hanging weight;

(7) recording the mass M of the standard suspended weight which can just cut off the current after collision, and considering that the equivalent acting force generated at the other end of the object to be researched is F1 ═ Mg after one end of the object to be researched is collided;

(8) setting the distance from the center of the suspended weight to the fulcrum of the balancing table as L1, and the distance from the center of the collision table to the fulcrum of the balancing table as L2; if the equivalent force of the collision platform after receiving collision impact is F2, F1L1 is F2L2, that is, F2 is F1L1/L2 is Mg L1/L2 according to the lever principle; the resultant force F applied to the fulcrum is F1+ F2 is Mg + Mg L1/L2, which is the equivalent acting force of the fastening bolt to be studied after the part with mass m and speed v is collided and impacted;

(9) the rigid collision can be regarded as momentum conservation, the collision block freely falls from the position with the height H, and rebounds to the height H after colliding with the collision table, the height H is observed and recorded through the vertical graduated scale or is shot and recorded by a high-speed camera and is compared with the vertical graduated scale for measurement, the velocity v when rebounding is equal to (2gh)1/2, the acting time of the collision block colliding with the collision table is t, and then the law of momentum conservation is followed: mv-mv trans-F2 t, giving a collision action time t-m (v-v trans)/F2-m ((2gH)1/2- (2gH)1/2)/(Mg L1/L2).

Images