JPH08177420A - Backlash measuring device in rolling mechanism - Google Patents

Abstract

PURPOSE: To measure backlash without innovating an internal combustion engine in a backlash measuring device of a rolling mechanism of a variable valve timing mechanism, etc., of the internal combustion engine. CONSTITUTION: A phase computing element 301 generates a signal corresponding to a phase difference of a camshaft and a crankshaft from pulse signals from a cam angle sensor 23 and a crank angle sensor 21, and by passing a phase difference signal from the phase computing element 301 throug a first band-pass filter 302, a frequency component decided by the number of engagement and the number of rotation of the piston with a housing which is a member of the side of a timing pulleyis taken out. Additionally, by passing a second band- pass filter 303, a frequency component decided by the number of teeth and the number of rotation of engagement of the piston and an inner gear which is a member on the side of the camshaft is taken out, and a voltage measuring device 304 displays amplitude=backlash of each of frequency signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlash measuring device in a device for transmitting rotation through a plurality of gears such as a variable valve timing device (VVT) of an internal combustion engine or a meshing member such as a spline.

[0002]

2. Description of the Related Art A variable valve timing device engages an internal spline member connected to the camshaft side and an outer spline member connected to a timing pulley with a piston having helical splines formed on the inner and outer peripheries to hydraulically move the piston. The valve timing is changed by changing the rotational phase between the inner spline member on the cam shaft side and the outer tap spline member on the timing pulley side (crankshaft side) by moving along the direction parallel to the axis line of the cam shaft. It is known to change things.

[0003]

In the variable valve timing device of the above-mentioned type, it is very important to control the backlash between the mutually engaged splines in order to obtain the desired valve timing suitable for the operating condition. Backlash is measured only after the device is assembled, but it is a laborious process that requires a lot of skill and is a bottleneck in process control.

Accordingly, the present invention is a device for transmitting rotation via a plurality of gears (eg, variable valve timing device).
It is an object of the present invention to provide a device capable of efficiently measuring the backlash of the gear member in (1) and (2) without modifying the variable valve timing device or the internal combustion engine in which the variable valve timing device is mounted.

[0005]

According to the present invention, in a rotating mechanism having a member having a plurality of meshes, a backlash measuring device includes a rotation signal generating means before and after the meshing, and a difference calculator of the rotation signals. , A band pass filter, a voltage measuring device, the band pass filter, at a predetermined rotation speed of the rotating mechanism, among the signals of the difference calculator, only the frequency component determined by the number of teeth and the rotation speed of the meshing. The voltage measuring device has a characteristic of passing, and measures and outputs the amplitude of the output of the bandpass filter.

[0006]

The rotation signal generating means generates a rotation signal before and after the meshing member, and the difference calculator calculates a difference in rotation signals before and after the meshing member from the rotation signal generating means.
The bandpass filter allows only the frequency component determined by the number of meshing teeth and the number of revolutions to pass through, with the number of revolutions of the rotating mechanism being a predetermined value. The voltage measuring device measures and outputs the amplitude of the output of the bandpass filter corresponding to the backlash.

[0007]

Embodiments of the present invention will now be described. In the present invention, a piston having helical splines formed on the inner and outer circumferences thereof is engaged with an inner spline member on the camshaft side and an outer spline member on the timing pulley side, and the piston is hydraulically operated on An embodiment applied to the measurement of backlash between splines in a variable valve timing device for an internal combustion engine in which the valve timing is changed by moving the valve timing along a direction parallel to the axis will be described.

First, the variable valve timing device will be described. In FIG. 1, reference numeral 1 is a crankshaft of an internal combustion engine, which is rotatably supported by a cylinder block (not shown). A timing pulley 2 is fixed on the crankshaft 1. On the other hand, 3 is a hollow cam shaft, which is rotatably supported by the cylinder head 4. Reference numeral 5 is a timing pulley that is connected to the camshaft 3 so that the rotational phase can be adjusted, and is wound around the timing pulley 2 on the camshaft 1 via a timing belt 6. That is, the timing pulley 5 has a cylindrical central boss portion 5 a, and this boss portion 5 a is fitted near the end portion of the cam shaft 3. The dish-shaped housing 7 accommodates the actuator portion of the variable valve timing mechanism inside, and the flange portion around the housing is fastened to the hub portion 5b of the timing pulley 5 by several bolts 8 to form the housing 7. Is integrated with the timing pulley 5 and rotates on the axis of the camshaft 7. For convenience of assembling, maintenance and inspection, repair, etc., the opening at the center of the bottom of the housing 7, which is the left end in FIG.
Is screwed on.

An inner gear 10 is provided at the end of the camshaft 3.
Are integrally attached by a head bolt 11, and the positioning pin 12 is driven into the camshaft 3 from the inner gear 10 so that the inner gear 10 is locked at a position relative to the camshaft 3 in the rotational direction. . Further, by fixing the inner gear 10 to the end of the cam shaft 3, the hub portion 5a of the timing pulley 5 is restrained, and the axial movement of the timing pulley 5 with respect to the cam shaft 3 is also prevented. However, the relative rotation of the timing pulley 5 with respect to the camshaft 3 is not disturbed.

Reference numeral 13 denotes a piston, which is composed of a disc-shaped portion 13-1 and a cylindrical portion 13-2 integral with the disc-shaped portion 13-1. Disk-shaped part 13
-1 is fitted on the cylindrical boss portion 5a at the center of the timing pulley 5 at the inner periphery thereof so as to be relatively rotatable and axially slidable, and at the outer periphery of the large diameter portion 7-1 of the housing 7. Slidingly fitted in oil-tightness to the peripheral cylindrical surface. A seal ring 15 is inserted in the annular groove of the outer peripheral portion of the piston 13 in order to improve the sealing performance. An advance-side hydraulic chamber 16A is formed on the side of the piston 13 close to the timing pulley 5 in the housing 13, and a retard-side hydraulic chamber 16B is formed on the side of the piston 13 away from the timing pulley 5.

Helical splines 13-2A and 13 are provided on a part of the inner surface and the outer surface of the cylindrical portion 13-2 of the piston 13, respectively.
-2B is formed and consists of a large number of teeth, each inclined with respect to the axial direction.
The teeth of -2A and the teeth of helical spline 13-2B are inclined in opposite directions. In the illustrated embodiment, the helical spline 13-2A has a left-hand thread, and the helical spline 13-2B has a right-hand thread. In this way, the helical splines 13-2A and 13-2B are inclined in opposite directions, and the camshaft 3
Helical splines 13-2A and 13-2B have positive and negative values for the inclination angle of the
Even if any one of the tooth traces is parallel to the axial direction, the same operation is performed, so that the inclination angle of one of the helical splines may be zero.

The helical spline 13-2B formed on the outer surface of the cylindrical portion 13-2 of the piston 13 is a helical spline 7-2A formed on the inner surface of the small diameter portion 7-2 of the housing 7.
The helical spline 13-2A formed on the inner surface of the cylindrical portion 13-2 meshes with the helical spline 10-A formed on the outer peripheral surface of the inner gear 10. Therefore, the helical spline on the inner surface of the housing 7
7-2A has a right-hand thread inclination angle according to the inclination of the tooth trace of the helical spline 13-2B of the piston 13-2. The helical spline 10-A on the outer surface of the inner gear 10 is the helical spline 13-2A. It has a left-hand thread inclination angle according to the inclination of the tooth trace.

The camshaft 3 and the head bolt 11 are provided with hydraulic passages 3a and 11a so as to penetrate through their respective central portions, and they form a first hydraulic passage. One end of each of the first hydraulic passages 3a and 11a is closed by the ball 14, but the other end is open to the advance-side hydraulic chamber 16B. This hydraulic passage is connected to the first output opening 17a of the hydraulic control valve 17 through the hole 3b of the camshaft 3, the annular groove 3c, and the first hydraulic passage 4a formed in the cylinder head 4 of the engine. It is in communication. On the other hand, the hydraulic chamber 16A on the retard side has a hole 5a-1 in the boss portion 5a of the timing pulley 5, an annular groove 3d corresponding to the hole 5a-1 formed in a part of the outer periphery of the camshaft 3, and a hole 3e.
Through the camshaft 3 is communicated with a second hydraulic passage 3f axially formed at a position deviated from the center of the camshaft 3, and the second hydraulic passage 3f is further provided with a hole 3g of the camshaft 3 and an annular groove. 3h, the second formed in the cylinder head 4 of the engine
The hydraulic pressure control valve 17 communicates with the second output opening 17b via the hydraulic passage 4b.

The hydraulic control valve 17 is generally called a spool valve because it has a spool 17c. The structure of the hydraulic control valve 17 is well known, so a detailed description thereof will be omitted. Solenoid 17 to drive
d is a plurality of plural spools 17c formed on the spool 17c by receiving a dither control signal supplied from a well-known electronic control unit (ECU) 18 which is a control unit of the engine, and causing the spool 17c to reciprocate in the axial direction. The land portion has the first output opening portion 17a and the second output opening portion 17a.
Open and close b for a short time. Then, by changing the ratio of the total time during which the ECU 18 opens the output openings 17a and 17b, the oil pressurized and supplied by the oil pump 19, that is, the lubricating oil of the engine,
It can be distributed in an arbitrary ratio and discharged to the output openings 17a and 17b.

In FIG. 1, a large number of projections 20 to be detected are fixed to the crankshaft 1 at equal intervals in the rotation direction, and a crank angle sensor 21 for detecting the rotation angle of the crankshaft 1 is provided facing the projections 20 to be detected. On the other hand, on the other hand, a large number of detected projections 22 are equally fixed in the rotational direction on the camshaft 3, and a cam angle sensor 23 of the camshaft 3 is arranged opposite to this. Sensors 21 and 2
Numeral 3 is a magnetic pickup specifically, which generates an electric pulse signal every time the protrusions 20 and 22 attached to the crankshaft 1 and the camshaft 3 pass, so that the number is counted by the ECU 18. if,
The rotation angle of each axis can be detected.

The control operation of the valve timing by the electronic control unit 18 will be described. The aforementioned hydraulic passage is opened for a short time when either output opening 17a or 17b of the hydraulic control valve 17 communicates with the oil pump 18. The oil is supplied to one of the advance side hydraulic chamber 16B and the retard side hydraulic chamber 16A via the above, and by repeating this, an arbitrary amount of pressurized oil is supplied to the hydraulic chamber 16A or the hydraulic chamber. 16B is supplied. At the same time as the oil is supplied to one hydraulic chamber, the same amount of oil is discharged from the other hydraulic chamber through the hydraulic control valve 17 and from the drain passage 17e to the oil pan of the engine. It moves axially to an arbitrary intermediate position where the axial forces generated by the control hydraulic pressures of the hydraulic chambers 16A and 16B become equal, or to the end of the movable range. In the case of the structure shown in the figure, the two hydraulic chambers 16 are provided in a state where the axial forces in the left and right directions are balanced and the piston 13 is stopped at the intermediate position.
The control hydraulic pressures of A and 16B have the same value.

When the piston 13 stops at any intermediate position within the movable range, the stop position is determined by the amount of oil remaining in the two hydraulic chambers 16A and 16B. Therefore, by changing the content of the dither control signal generated by the ECU 18, each hydraulic chamber 16
By finely adjusting the amount of oil supplied to A and 16B, the stop position of the piston 13 can be adjusted steplessly and freely. Thereby, the opening / closing timing of the intake valve and the exhaust valve of the internal combustion engine can be smoothly changed.

In such a variable valve timing mechanism, the rotation of half the rotational speed is transmitted from the crankshaft 1 to the timing pulley 5 on the driven side by the timing pulley 2 on the driving side and the timing belt 6. Rotation is from the helical spline 7-2A of the housing 7 through the helical splines 13-2B and 13-2A of the piston 13 to the inner gear 10 having the helical spline 10-A.
And the rotation thereof is transmitted from the positioning pin 12 to the cam shaft 3 to drive the cam. This causes valves such as the intake and exhaust valves to open and close the intake or exhaust ports.

The relative phase relationship between the timing pulley 5 and the cam shaft 3 can be freely changed by the action of the two pairs of helical splines meshing with each other by moving the piston 13 in the axial direction. As described above, the axial position of the piston 13 controls the amount of oil supplied to the hydraulic chamber 16B on the advance side and the hydraulic chamber 16A on the retard side by the hydraulic control valve 17 operated by a command from the ECU 18. It depends on what you do. ECU18
Receives the signals generated by the cam angle sensor 23, the crank angle sensor 21 and the like to calculate the cam phase and the rotational speed, compare them with map data of the optimum cam phase for the operating conditions of the internal combustion engine, and A dither control signal is generated to reduce the difference between the cam phase and the value of the map data, and the current supplied to the solenoid 17d of the hydraulic control valve 17 is interrupted.

When the amount of oil in the hydraulic chamber 16B on the advance side increases and the control hydraulic pressure rises due to the action of the hydraulic control valve 17, the piston 13 is pushed to the right in FIG. Since the cylindrical portion 13-2 of the piston 13 and the housing 7 are engaged with each other by the right-handed helical splines 13-2B and 7-2A, the piston 13 rotates clockwise relative to the housing 7 when viewed from the left side of FIG. Will be done. Further, since the piston 13 and the inner gear 10 are meshed with each other by the helical splines 13-2A and 10-A, the inner gear 10 moves rightward with respect to the piston 13 together with the camshaft 3 by the rightward movement of the piston 13 as described above. Can be rotated around. In this way, the timing of the valve driven by the camshaft 3 is advanced by the amount of movement of the piston 13 in the axial direction.

On the contrary, when the spool 17c of the hydraulic control valve 17 is moved by the control signal of the ECU 18 and the oil is supplied to the hydraulic chamber 16A on the retard side, the piston 13 is moved leftward and the camshaft is moved. The timing of the valve driven by 7 will be retarded. In this way, the phase of the timing pulley 5, and thus of the camshaft 3 with respect to the crankshaft 1, is adjusted steplessly. Also in the illustrated embodiment, the basic operation as described above is the same as that of the conventional variable valve timing mechanism.

As described above, in the apparatus shown in FIG. 1, the housing 7 that rotates integrally with the timing pulley 5 that is wound around the timing pulley 2 on the crankshaft 1 and the camshaft 3 that is integrally rotated with the housing 7. The timing piston 13 is arranged between the inner gear 10 and the helical spline 13-2B of the cylindrical portion 13-2 of the piston 13 and the helical spline 7-2A of the housing 7 and the helical spline 13 of the cylindrical portion 13-2. -2
The timing pulley 5 is rotated by the camshaft 3 by the meshing of A with the helical spline 10-A of the inner gear 10.
Is transmitted to Therefore, it is important to obtain a desired valve timing characteristic that the backlash of these meshing portions is controlled to be constant. The configuration of the backlash measuring device 30 of the present invention for measuring the backlash of these two sets of meshes will be described below.

As shown in FIG. 2, the backlash measuring device 3
0 is the phase difference calculator 301 and the first bandpass filter 3
02, a second bandpass filter 303, and a voltage measuring device 304. Although the phase difference calculator 301 is known per se, its first input 301-1 is connected to the crank angle sensor 21 and its first input 301-2 is connected to the cam angle sensor 23. The phase is calculated from the pair of pulse signals by the Hilbert transform, and then a signal corresponding to the phase difference is output. The first bandpass filter 302 has a predetermined number of rotations of the camshaft 3 depending on the number of teeth of the meshing portion of the helical spline 13-2B of the cylindrical portion 13-2 of the piston 13 and the helical spline 7-2A of the housing 7. Frequency signal s multiplied by frequency
_It is configured to pass only ₁ . The second bandpass filter 303 includes a helical spline 13-2A of the cylindrical portion 13-2 of the piston 13 and a helical spline of the inner gear 10.
Camshaft 3 for the number of teeth of the meshing part with 10-A
It is configured so that only the signal s ₂ having a frequency obtained by multiplying the frequency of the predetermined rotation speed of is passed. The voltage measuring device 304 is configured to read and display the respective amplitudes of the signals s ₁ and s ₂ from the bandpass filters 302 and 303.

The operation of the structure for measuring the backlash of the meshing portion of the above structure will be described below. Phase calculator 30
1 is from the cam angle sensor 23 and the crank angle sensor 21,
The cam rotation phase and the crank rotation phase are calculated, and the phase difference is obtained. That is, since the camshaft 3, the piston 13, and the timing pulley 5 have slight clearance and backlash at the sliding parts and the meshing parts for the convenience of assembly, the shafts of the respective rotations in the assembled state. Is also slightly shifted. Therefore, the cylindrical portion of the piston 13
13-2 of the helical spline 13-2B and the housing 7 of the helical spline 7-2A and the cylindrical portion 13-2 of the helical spline 13-2A and the inner gear 10 of the helical spline 10-A meshing of two sets of The meshing is only one point on the circumference of each meshing. As a result, the fluctuation of the rotational phase difference due to the backlash of meshing has a frequency component of 1 / (meshing teeth number × rotational speed) when operating at a constant rotation speed.

The bandpass filters 302 and 303 have two
Since only the above-mentioned frequency components of the meshes of the set are passed, the amplitude of the output signal s ₁ thereof is equal to the helical spline 13-2B of the cylindrical portion 13-2 of the piston 13 and the housing 7.
Shows the meshing of the meshing part with the helical spline 7-2A, and the amplitude of the output signal s ₂ is the cylindrical part 13 of the piston 13.
The backlash of the meshing portion between the helical spline 13-2A of -2 and the helical spline 10-A of the inner gear 10 is shown.

The amplitude of the above output is measured and displayed by the voltage measuring device 304. In order to prevent gear rattling noise caused by backlash, if the backlash of one of the two sets of meshing exceeds the specified value as a result of the above measurement, parts related to the meshing will be replaced. Become. In the above embodiment, the backlash of the variable valve timing mechanism was measured, but it can be measured in the same manner as long as it has a plurality of meshes and can measure the rotational phase before and after meshing.

In the above embodiment, a magnetic cam angle sensor,
Although the phase of the rotation is detected by the crank angle sensor, the detection method of the sensor may be rotation detection such as optical detection, and the rotation detection may be angular velocity or angular acceleration.

[0028]

According to the present invention, rotation signals before and after the above meshing are generated with respect to a gear or a spline mechanism, and the number of meshing teeth is determined by using a bandpass filter from the phase difference of each rotation signal. Take out the variable component according to
By measuring the amplitude, the backlash of the meshing portion can be measured, and there is no need to modify the internal combustion engine or the like to which the gear device is attached.

[Brief description of drawings]

FIG. 1 is a sectional view of a variable valve timing device for an internal combustion engine to which the present invention is applied.

FIG. 2 is a block diagram showing a configuration of the backlash measuring device in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Crankshaft 2 ... Timing pulley 3 ... Camshaft 5 ... Timing pulley 7 ... Housing 7-A ... Spline 10 ... Inner gear 10-A ... Spline 13 ... Piston 13-2A ... Spline 13-2B ... Spline 21 ... Crank angle sensor 23 ... Cam angle sensor 30 ... Backlash measuring device 301 ... Phase difference calculator 302 ... First bandpass filter 303 ... Second bandpass filter 304 ... Voltage measuring device

Claims (2)

[Claims] 1. A rotation mechanism having a member having a plurality of meshes, comprising rotation signal generating means before and after the meshing, a difference calculator of the rotation signals, a bandpass filter, and a voltage measuring device, The filter has a characteristic of passing only a frequency component determined by the number of teeth and the number of revolutions of the meshing in the signal of the difference calculator at a predetermined number of revolutions of the rotating mechanism. A backlash measuring device in a rotating mechanism, which measures and outputs the output amplitude of a filter. 2. A variable valve timing mechanism is provided between the power transmission member and the cam shaft, wherein a power transmission member from the crank shaft of the internal combustion engine to the cam shaft is rotatably provided on the cam shaft. Is a moving member that moves in a direction parallel to the axis of the camshaft,
The rotary member is provided between the moving member and the power transmitting member and between the moving member and the cam shaft, and the rotation of the rotating member is transmitted to the cam shaft side while the moving member does not move along the direction with respect to the rotating member and the cam shaft. A cam portion which allows the relative rotation between the power transmission member and the cam shaft by this movement, and further, a first rotation signal generating means for generating a signal according to the rotation of the crankshaft; and a cam. Of the signals of the second rotation signal generating means for generating a signal according to the rotation of the shaft, the calculator of the difference between the rotation signals from the first and second rotation signal generating means, and the signal of the difference calculator, the moving member A first band-pass filter having a characteristic of passing only frequency components corresponding to the number of teeth and the number of rotations of the meshing portion between the power transmission member side and
Of the signals of the difference calculator, the second bandpass filter having the characteristic of passing only the frequency component corresponding to the number of teeth and the number of rotations of the meshing portion of the moving member and the camshaft side, and the output of the bandpass filter A backlash measuring device for a variable valve timing device for an internal combustion engine, comprising: a voltage measuring device for measuring and outputting an amplitude.