JP4085684B2 - Cam piece reference phase position detection method, cam piece phase comparison method, cam piece reference phase position detection device, cam piece phase comparison device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cam piece reference phase position detection method, a cam piece phase comparison method, a cam piece reference phase position detection device, a cam piece phase comparison device, and more particularly, a cam piece reference phase position, for example, a vertex position detection, and a reference phase position. The present invention relates to improvement of phase comparison of cam pieces using (for example, apex position).
[0002]
[Prior art]
Conventionally, a cam has been used as one of drive transmission parts of a mechanical device. The performance of this cam depends on how close the cam profile of the actual cam can be to a desired profile, for example a cam profile based on design values. In general, since the cam profile has a delicate curve, it is necessary to make it by comparing it with a design value or a reference product a plurality of times. In addition, for mass-produced cams and cams in use, it is necessary to accurately grasp the shape in order to perform performance determination and correction processing, so it is necessary to compare the cam profile based on design values and reference products. Furthermore, when performing correction (additional machining) in order to make a cam piece, it is also necessary to accurately grasp how the shape has changed before and after the correction.
[0003]
Normally, a two-dimensional cam (such as a flat cam) is not connected to a cam piece alone but is connected to a camshaft or the like, so a specific position on the shaft, for example, a spline tooth position or a knock pin hole position, etc. Is a reference position, that is, a cam rotation angle of 0 ° (phase angle of 0 °), and a cam profile of an actual cam piece can be compared with a cam profile based on a design value or the like. Similarly, when comparing shapes before and after correction, the tooth position, hole position, and the like do not change. Therefore, the cam profiles can be easily compared by comparing both based on the tooth position and hole position.
[0004]
On the other hand, when it is necessary to perform profile comparison with the cam piece alone in the manufacturing process, for example, in the case of a three-dimensional cam whose cam surface continuously changes with respect to the rotation axis direction, a reference position that is characteristic on the cam piece It is necessary to determine. By matching the reference position defined on the cam piece with the reference position defined on the design value of the cam piece, the cam profiles of both can be compared. Usually, when the reference position is determined on the cam piece, the vertex position where the lift amount is maximum is used. Of course, even in a two-dimensional cam, there are cases where the reference position cannot be determined in a portion other than the cam piece, or there are cases where it is necessary to compare the cam profiles of the cam piece alone. In such a case, the vertex position is used as described above.
[0005]
By the way, the determination of the vertex position of the cam piece can be defined as the maximum value of the lift amount as described above. However, in practice, the lift amount does not change much even if the cam piece is rotated near the vertex. As a result, an accurate vertex position could not be determined only by detecting the lift amount with a conventional cam tester for cam profile measurement.
[0006]
Therefore, conventionally, a cam piece apex position estimating method as shown in FIG. 8 has been used. That is, as shown in FIG. 8 (a), in the cam piece design value, a predetermined angle θ (= ∠A0OT0 = ∠B0OT0: across the center line L including the rotation center O of the campiece 100 and the apex T0 on the design value: The points A0 and B0 are determined so as to be 20 °. Subsequently, the lift amount a at the point A0 and the lift amount b at the point B0 are obtained. Subsequently, as shown in FIG. 8B, a point A that is the lift amount a and a point B that is the lift amount b are detected from the actual total lift amount of the cam piece 102, and ∠AOT = ∠BOT A point T such that This point T is determined by estimating the actual vertex position of the cam piece 102.
[0007]
[Problems to be solved by the invention]
However, when the vertices of the actual cam piece 102 are determined by the method as described above, if the shape of a part of the cam profile is far away from the design value, the influence of the difference from the design value is calculated when calculating the vertex. As a result, a phenomenon occurs in which the vertex position deviates from the true position, that is, the position where the lift amount is maximum. That is, since the point A and the point B move according to a part of the shape, the value of ∠AOT = ∠BOT changes and the vertex position changes to the point T. That is, there is a problem that the vertex position to be a reference for comparison cannot be determined. Similarly, when the cam piece is corrected based on a comparison with the design value, the result is that the apex position estimated by the shape change before and after the correction is shifted from the true position, and the comparison before and after the correction is actual. There is a problem that can not be. When the cam profile of the actual cam piece 102 is changed at the portion α as shown in FIG. 9A, as described above, the vertex position T is changed by the correction of the portion α as shown in FIG. 9B. It moves from the vertex position T0 before correction. In this state, when comparing the shape of FIG. 9A before correction with the shape of FIG. 9B after correction by superimposing the vertex positions, as shown in FIG. The part β that has not been corrected is as if it has been corrected, and not only the cam profiles before and after the correction cannot be compared, but also the correction work is confused.
[0008]
The present invention has been made in view of the above problems, and a cam piece reference phase position detecting method, a cam piece phase comparing method, and a cam piece reference phase capable of accurately and easily determining a reference phase position of a cam piece, for example, a vertex position. It is an object of the present invention to provide a position detection device and a cam piece phase comparison device.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a cam piece reference phase position detection method, and an actual measurement step for measuring a lift amount, which is a distance from a rotation center of the cam piece to a cam surface, and is measured. A conversion step for converting the lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece, an extraction step for extracting a switching point where the positive change rate and the negative change rate of the lift change rate are switched, and the extracted switching point A reference determining step in which any one of them is used as a reference phase position of the cam piece.
[0010]
In order to achieve the above object, the present invention is a cam piece reference phase position detection device, and an actual measurement means for measuring a lift amount, which is a distance from a rotation center of the cam piece to a cam surface , A conversion means for converting the measured lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece; an extraction means for extracting a switching point at which the positive change rate and the negative change rate of the lift change rate are switched; And a reference determining means for setting any one of the switching points as a reference phase position of the cam piece.
[0011]
Here, the reference phase position is a position that serves as a reference in considering the cam profile of the cam piece, and is preferably the lift amount apex position of the cam piece.
[0012]
According to this configuration, the switching point is always fixed without being affected by the change in the shape of the cam piece other than the switching point. That is, if a switching point determined based on the actually measured lift amount is set as a reference phase position, for example, a vertex position, a point on the cam piece can be used as a reference for comparison.
[0013]
Further, in order to achieve the above object, the present invention is a cam piece phase comparison method, and an actual measurement step for measuring a lift amount, which is a distance from the rotation center of the cam piece to a cam surface, is measured. A conversion step for converting the lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece; an extraction step for extracting a position at which the positive change rate and the negative change rate of the lift change rate are switched as a vertex position of the cam piece; A reference line setting step for setting a reference line that connects the extracted vertex position and the center point of the cam piece, and a design reference line that connects the lift vertex position and the center point of the cam piece in the design value of the cam piece and the above-mentioned reference line are superimposed and measured. A comparison step for comparing the cam profile and the design value cam profile for each phase, and a presentation step for presenting the comparison result Characterized in that it comprises a.
[0014]
In order to achieve the above-described object, the present invention is a cam piece phase comparison device, and a measurement means for measuring a lift amount, which is a distance from the rotation center of the cam piece to the cam surface . Conversion means for converting the lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece, an extraction unit for extracting a position at which the positive change rate and the negative change rate of the lift change rate are switched as a vertex position of the cam piece; A reference line connecting the extracted vertex position and the center point of the cam piece is set, the design reference line connecting the lift vertex position and the center point of the cam piece in the design value of the cam piece and the reference line are superimposed, and the measured cam piece and the design value A comparison unit that compares the cam profiles for each phase and a presentation unit that presents the comparison result.
[0015]
According to this configuration, it is possible to easily and accurately compare the profile of the designed cam piece and the cam profile of the actual cam piece.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.
[0017]
FIG. 1 shows a schematic configuration diagram of a cam tester integrated device 10 that can be used as a reference phase position detecting device for a cam piece and a phase comparing device for a cam piece according to the present embodiment. This cam tester-integrated apparatus 10 supports a cam piece (for example, a three-dimensional cam whose cam surface continuously changes in the rotation axis direction) 14 on a bed 12 using a support material such as an arbor 16. Yes. Further, on the bed 12, the arbor 16 is supported, the head part 18 that rotates the cam piece 14 via the arbor 16, and the tail part that supports the other end of the arbor 16 and presses against the head part 18 side. 20 is arranged. The head unit 18 is rotatable by a drive mechanism unit 22 (detailed structure is not shown) composed of a motor, a gear, and the like, and controls the rotation of the arbor 16, that is, the cam piece 14 at a predetermined speed. Further, a measuring head portion 24 having a measuring element 24a that contacts the cam surface 14a of the cam piece 14 supported by the arbor 16 and measures the cam profile is disposed at a substantially central position of the bed 12. The measuring element 24a advances and retreats according to the shape of the cam surface 14a that comes into contact (advances and retreats in the vertical direction in FIG. 1), and the distance from the rotation center of the cam piece 14 to the cam surface 14a is a predetermined rotation angle (for example, 0. Measured every 1 °. The amount of advancement / retraction of the measuring element 24 a is the lift amount of the cam piece 14. Of course, the lift amount may be measured continuously.
[0018]
In addition, a display 26 is arranged as a presentation unit that displays the measured lift amount and various calculation results on an arbitrary position of the cam tester integrated device 10, for example, on the drive mechanism unit 22. On the other hand, a control unit 28 that performs overall control of the cam tester integrated device 10 and various arithmetic processing described later is disposed below the bed 12.
[0019]
A characteristic matter of this embodiment is that a lift change rate is calculated from the measured lift amount of the cam piece 14, and a reference position of the cam profile of the cam piece to be measured, that is, a reference phase position is determined based on the lift change rate. It is in place. Further, using this reference phase position, the cam piece 14 to be measured is compared with its design value.
[0020]
As described above, the control unit 28 includes an overall control of the cam tester integrated device 10, for example, a mechanism control unit that controls the drive mechanism unit 22, a measurement data calculation unit, and the like. A schematic configuration of this calculation unit is shown in FIG. The calculation unit 30 includes a lift change rate conversion unit (converting unit) 32 that converts the lift amount actual measurement data measured by the measurement head unit 24 (actual measurement unit) into a lift change rate for each predetermined unit rotation angle of the cam piece. A switching point at which a positive change rate and a negative change rate are switched is extracted, and a reference phase position, specifically, a vertex position calculation unit (extraction means, reference determination means) 34 for calculating a vertex position, a determined reference phase position ( A comparison unit (comparison means) 36 for comparing the cam profile of the cam piece 14 to be measured with respect to the apex position) and a cam profile based on a predetermined design value is included. The cam piece rotation angle measurement data necessary to compare the lift change rate and the profile is obtained by measuring the rotation amount of the motor of the drive mechanism 22 and the actual rotation amount of the cam piece 14 using various sensors. Can be acquired.
[0021]
The control unit 28 configured as described above is an example, and a processing device 38 having an operation unit is additionally connected to a conventional cam tester that measures only the cam profile, and is equivalent to the control unit 28 described above. You may make it give a function.
[0022]
The procedure for determining the reference phase position (vertex position) of the cam tester integrated device 10 configured as described above will be described below. In the present embodiment, various measured values and converted values are shown as graphs for the sake of explanation. However, the actual calculation unit 30 does not necessarily need to be graphed. May be selectively created and displayed on the display 26.
[0023]
The cam tester-integrated device 10 first has a position offset by a predetermined amount from the cam end surface of the cam piece 14 to be measured (refer to the cam piece in FIG. 1) in the cam piece 14 set on the arbor 16 as usual by the measuring head 24. 14, for example, a lift amount for each cam rotation angle as shown in FIG. 3 is measured using a measuring element 24 a (a position away from the right end face by a predetermined amount to the left) (measurement step). In the case of FIG. 1, the cam piece 14 is rotated once, and the lift amount is measured and graphed, for example, at every cam rotation angle of 0.1 °.
[0024]
Subsequently, the lift change rate conversion unit 32 converts the lift amount measured by the measurement head unit 24 into a lift change rate for each predetermined unit rotation angle (for example, every 0.1 °) of the cam piece 14 (conversion step). FIG. 4 shows the lift amount converted into a lift. What should be noted here? In the case of a cam piece, there are several tops for lifting the cam follower in contact with the cam surface 14a to a predetermined position, and before and after the top, the rate of change in lift is switched between a positive rate of change and a negative rate of change. That's what it means. In the example of FIGS. 3 and 4 showing the present embodiment, it is shown that there is one position where the lift amount is maximum, that is, one apex position of the cam piece 14 and the cam angle is around 0 °. When the graph is used, the switching point at which the positive change rate and the negative change rate are switched to each other can be easily obtained from the intersection of the horizontal axis and the graph. Further, in calculation, it can be easily obtained by searching for the position of the lift change rate “0”. Note that although there is a switching point where the positive change rate and the negative change rate are switched to each other even at a position rotated from 0 ° to 180 °, in this embodiment, the cam angle is 0 in which the change in the front and rear is large and the apex position is clear. Focus on around °. In the present embodiment, the lift amount is detected every 0.1 °, for example. However, this angle is arbitrary and can be appropriately selected according to the detection accuracy. Similarly, when the lift change rate is obtained, the predetermined unit rotation angle is shown to be, for example, every 0.1 °, but this angle is arbitrary and can be appropriately selected according to the detection accuracy. When the lift amount and lift are obtained as discontinuous plot data, it is not desirable to make the angle too wide, but using the least square method etc. improves the accuracy of the lift conversion amount based on the measured lift amount. can do.
[0025]
FIG. 5 shows a further enlargement of the vicinity of the portion where the positive change rate and the negative change rate near the cam angle of 0 ° are switched. And the vertex position calculation part 34 extracts the switching point in which a positive change rate and a negative change rate switch mutually (extraction step). In the example of FIG. 5, the switching point exists at a position offset to the left by about 0 to 0.4 degrees from the cam angle. That is, it means that the measured vertex position of the cam piece 14 is shifted by about 0.4 ° from the position recognized by the cam tester integrated device 10. Accordingly, the vertex position calculation unit 34 recognizes the offset position as the reference phase position, and corrects the cam angle 0 ° to this position (reference determination step).
[0026]
In this case, the position at which the positive change rate and the negative change rate are switched does not change unless the vertex position itself is corrected. That is, even if the shape of the portion other than the vertex position of the cam piece 14 is corrected, the vertex position does not change due to the influence of the correction processing as in the prior art. As a result, once the switching point described above is determined as the reference phase position of the cam piece 14, that point can always be set as the reference position of the cam piece 14 and used as a comparison value before and after the design value and correction processing.
[0027]
For reference, FIG. 6 shows a graph of the relationship between the cam angle and the lift amount based on the design value of the cam piece 14. Normally, in the design of the cam piece, since the vertex position is set to the phase position 0 °, as shown in FIG. 7, the graph converted into the lift change rate with respect to the lift amount has a positive change rate and a negative change rate. The switching point at which is switched is precisely at a cam angle of 0 °. In the case of FIG. 6, since the lift amount of the three-dimensional cam is such that the cam surface 14a continuously changes in the rotation axis direction, lift curves based on a plurality of profiles appear. FIG. 7 shows a graph converted into a lift change rate by paying attention to an arbitrary lift curve in FIG.
[0028]
In the above description, the case where the cam tester integrated device 10 is used as the reference phase position detection device for the cam piece has been described. However, when the cam tester integrated device 10 is used as the cam piece phase comparison device, the calculation unit 30 is further provided. The comparison unit 36 sets a reference line that connects the determined vertex position and the center point of the cam piece (reference line setting step), and determines the lift vertex position from the design value of the cam piece 14 that can be obtained from a host system or the like. A design reference line connecting the center points of the cam piece 14 is acquired, the reference line and the design reference line are superimposed, profiles based on the actual measurement value and the design value are superimposed, and profile comparison is performed for each phase (comparison step).
[0029]
As described above, the cam tester integrated device 10 can accurately recognize the vertex position (reference phase position) of the actual cam piece 14 to be measured, and easily compare with the design value based on the vertex position. Can be done. As a result of the comparison, for example, it is possible to clearly show how many parts should be corrected from the apex position (cam angle 0 °) in order to make the shape of the actual cam piece 14 closer to the design value. The result of comparison between the design value and the actual measurement value can be displayed as a numerical value or a graph on the display 26 for each cam angle. This comparison result can be used, for example, in determining whether the shape is good or not with respect to the design value of the cam piece. In addition, as cam piece wear data, a database can be constructed and used as basic data for cam piece design changes.
[0030]
In addition, as a result of comparison, even if the 5 ° plus position is corrected from the vertex position, the next calculated vertex position can be recognized at the same position as the previous time, so comparison with the design value can be easily performed again. Can do. Furthermore, since the shapes before and after the correction can be compared using the vertex position as a reference, it is possible to easily grasp the change in the shape before and after the correction and the necessity of the correction.
[0031]
1 and 2 described in the present embodiment is an example, and the reference phase is obtained by measuring the lift amount of the cam piece, calculating the lift change rate based on the lift amount, and obtaining the switching point. The position (preferably the vertex position) is calculated and can be appropriately changed as long as the configuration is used for comparison with the design value and the shape before and after correction, and the same effect as in the present embodiment can be obtained.
[0032]
In the above-described embodiment, a three-dimensional cam is described as an example. However, even in a two-dimensional cam (a flat cam or the like), when a reference point cannot be determined in a portion other than the cam piece, or the profile measurement is performed with the cam piece alone. When it is necessary to perform the same as in the present embodiment, it is possible to determine the reference phase position (for example, apex position) at the position on the cam piece using the lift change rate, and the same effects as in the present embodiment Can be obtained.
[0033]
【The invention's effect】
According to the present invention, the switching point is always determined to be constant without being affected by a change in the shape of the cam piece other than the switching point. That is, if the switching point is a reference phase position, for example, a vertex position, a point on the cam piece can be used as a reference for comparison, so that comparison with design values and shapes before and after correction can be performed easily and accurately. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a conceptual configuration of a cam tester integrated device according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a calculation unit of the cam tester integrated device according to the embodiment of the present invention.
FIG. 3 is a graph illustrating lift amounts for each cam angle used in the cam tester integrated device according to the embodiment of the present invention.
FIG. 4 is an explanatory diagram illustrating a lift change rate for each cam angle used in the cam tester integrated device according to the embodiment of the present invention.
5 is an enlarged view in which the vicinity of a cam angle of 0 ° in the graph of FIG. 4 is enlarged.
FIG. 6 is an explanatory diagram that graphs the lift amount for each cam angle based on the design value of the cam piece.
FIG. 7 is an explanatory diagram that graphs the rate of change in lift for each cam angle based on the design value of the cam piece.
FIG. 8 is an explanatory diagram for explaining a conventional cam piece apex position estimating method;
FIG. 9 is an explanatory diagram for explaining misrecognition caused by a vertex position estimated by the method of FIG. 8;
[Explanation of symbols]
10 cam tester integrated device, 12 beds, 14 cam pieces, 14a cam surface, 16 arbor, 18 head, 20 tail, 22 drive mechanism, 24 measuring head, 24a probe, 26 display, 28 controller, 30 arithmetic Part, 32 lift change rate conversion part, 34 vertex position calculation part, 36 comparison part.

Claims (5)

A method of detecting a reference phase position of a cam piece,
An actual measurement step for measuring a lift amount which is a distance from the rotation center of the cam piece to the cam surface ;
A conversion step for converting the measured lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece;
An extraction step for extracting a switching point at which a positive change rate and a negative change rate of the lift change rate are switched;
A reference determining step in which any one of the extracted switching points is set as a reference phase position of the cam piece;
A reference phase position detecting method for a cam piece. The method of claim 1, wherein
The reference phase position detection method for a cam piece, wherein the reference determining step uses a vertex position where the lift amount of the cam piece is maximized as a reference phase position. A cam piece phase comparison method,
An actual measurement step for measuring a lift amount which is a distance from the rotation center of the cam piece to the cam surface ;
A conversion step for converting the measured lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece;
An extraction step of extracting the position at which the positive change rate and the negative change rate of the lift change rate are switched as the apex position of the cam piece;
A reference line setting step for setting a reference line connecting the extracted vertex position and the center point of the cam piece;
A comparison step of superimposing the reference line and the reference line connecting the lift apex position in the design value of the cam piece and the center point of the cam piece, and comparing the measured cam piece and the cam profile of the design value for each phase;
A presentation step for presenting the comparison results;
The phase comparison method of the cam piece characterized by including. A cam piece reference phase position detector,
Actual measurement means for measuring a lift amount which is a distance from the rotation center of the cam piece to the cam surface ;
Conversion means for converting the measured lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece;
Extraction means for extracting a switching point at which a positive change rate and a negative change rate of the lift change rate are switched;
A reference determining means for setting any one of the extracted switching points as a reference phase position of the cam piece;
A reference phase position detection device for a cam piece, comprising: A cam piece phase comparison device comprising:
Actual measurement means for measuring a lift amount which is a distance from the rotation center of the cam piece to the cam surface ;
Conversion means for converting the measured lift amount into a lift change rate for each predetermined unit rotation angle of the cam piece;
An extraction unit for extracting a position at which the positive change rate and the negative change rate of the lift change rate are switched as a vertex position of the cam piece;
A reference line connecting the extracted vertex position and the center point of the cam piece is set, the design reference line connecting the lift vertex position and the center point of the cam piece in the design value of the cam piece and the reference line are superimposed, and the measured cam piece and the design value A comparison unit for comparing each cam profile of each phase,
A presentation unit for presenting the comparison results;
A phase comparison device for a cam piece, comprising:

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