JP2003121104A - Three-dimensional cam profile measuring method and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional cam profile measuring method capable of measuring the cam profile of a three-dimensional cam with high accuracy by easy constitution, and a three-dimensional cam profile measuring apparatus adapted thereto. SOLUTION: The three-dimensional cam profile measuring apparatus includes a profile measuring instrument 14 for measuring the profile of the three- dimensional cam 12, an end surface detector 16 for detecting the end surface 22 of the three-dimensional cam 12 for determining the profile measuring position due to the profile measuring instrument 14, and a CPU 20 performing control for moving them in the rotary axis direction of the three-dimensional cam 12. The CPU 20 initially moves the end surface detector 16 to the end surface of the three-dimensional cam 12 until the detection element 16a thereof is transferred to a stable detection region A, where a detection value is stabilized after the contact with the end surface 22. The detection value obtained at this time is supplied as the moving correction value of the profile measuring instrument 14, and added to the predetermined moving quantity from the end surface 22 of the profile measuring instrument 14 to control movement.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a three-dimensional cam profile measuring method and a three-dimensional cam profile measuring device,
In particular, the present invention relates to an improvement of a three-dimensional cam profile measuring method and a three-dimensional cam profile measuring device that can easily perform accurate measurement.

[0002]

2. Description of the Related Art Conventionally, a cam has been used as one of the drive transmission components of a mechanical device. Generally, the cam is a disk type or a cylinder type, and the distance from the center of the rotation shaft to the cam surface with which the cam follower abuts can be changed by making the cross section an elliptical shape or an eccentric shape, or by making the rotation shaft eccentric. By doing so, the cam follower can be driven by a predetermined amount at a predetermined timing. Therefore, since the cam profile of the cam surface has a great influence on the accuracy of the cam drive, the measurement of the cam profile is very important at the time of designing, manufacturing and subsequent use.

Conventionally, the distance from the center of the rotation axis of a disc cam or a cylindrical cam to the cam surface is uniform in the direction along the rotation axis. Therefore, a profile measuring device for measuring a cam profile is, for example, a cam surface. The measurement can be performed by pressing a probe that can move back and forth in the vertical direction against the cam surface and rotating the cam around the rotation axis. As described above, since the cam profile of the disc cam or the like is uniform in the direction along the rotation axis, it is possible to obtain the same measurement result even if the probe is brought into contact with any position on the cam surface.
Good cam profile measurements can be made.

[0004]

By the way, among the cams having various shapes depending on the use, a so-called three-dimensional cam having a three-dimensional shape in which the cam surface continuously changes in the rotational axis direction. Is described, for example, in Japanese Patent Laid-Open No. 11-210427. This cam is used, for example, as a cam that drives an intake valve and an exhaust valve of an internal combustion engine. Then, by controlling so that a predetermined position on the cam surface contacts the cam follower, the cam profile can be substantially changed. That is, it is possible to create a cam having a plurality of profiles, and it is possible to control the square root characteristic of those valves by changing the contact position of the cam follower according to the motion condition of the internal combustion engine.

FIG. 5 is an explanatory view for explaining the concept of cam profile measurement of a three-dimensional cam. 3D cam 100
As shown in the side view on the right side of FIG. 5, the cam surface 100 a is inclined with respect to the axial direction of the rotation shaft (shaft hole) 102.
Therefore, as the contact position of the cam follower moves to the left side of the cam surface 100a, the lift amount of the cam follower can be reduced. This is the same when the cam profile is measured, and the measurement result greatly varies depending on the contact position of the tracing stylus 104a of the profile measuring instrument 104 (only the tip is shown). Of course, when measuring the cam profile, the contact point 10 is placed at the position where the cam follower comes into contact.
Although the measurement control is performed so as to bring the 4a into contact with the profile measuring device 104, which measures the conventional disc cam or the like, the positional accuracy in the rotational axis direction is not required for the axial measurement position (rotational axis direction). Since the cam profile of No. 1 is the same), the contact position accuracy of the tracing stylus 104a was low in the rotation axis direction. That is, the conventional profile measuring instrument 1
Even when the cam profile of the three-dimensional cam is measured using 04, there is a problem that the measurement accuracy is low and the reliability is low.

The present invention has been made in view of the above problems, and a three-dimensional cam profile measuring method and a three-dimensional cam profile measuring apparatus capable of highly accurately measuring the cam profile of a three-dimensional cam with a simple structure. The purpose is to provide.

[0007]

To achieve the above object, the present invention has a cam surface with which a cam follower abuts, and the cam profile of the cam surface is continuous in the direction of the rotation axis. In a method for measuring a cam profile of a three-dimensional cam that changes, a step of moving the entire end face detector including a detector toward an end face in the rotation axis direction of the three-dimensional cam, the detector contacting the end face. After that, a step of initially moving the entire end face detector until the detection value of the end face detector moves to a stable detection region where the detection value becomes stable, and a detection value in the stable detection region obtained by the initial movement is three-dimensionally cammed. As a movement correction value of the profile measuring instrument in the direction of the rotation axis, a step of adding a predetermined movement amount from the end face of the profile measuring instrument, and the profile measuring instrument at the position where the correction movement is performed. Constant, and characterized in that it comprises the steps of measuring the cam profile of the three-dimensional cam is rotated about the rotary shaft 3D cam, a.

Here, the stable detection area means an area where the detection error by the detector of the end face detector falls within the allowable range. For example, in the case of a detector that detects a professional end face position by the amount of movement of the detector, the error in the detection position is the neutral point in the state where a predetermined load is applied, for example, a detector that can detect positive and negative values. Nearest (measured value ± 0),
The error increases as the amount of movement of the detector is too small or too large. Therefore, the stable detection area is set, for example, near the measurement neutral point of the detector of the detector. Therefore, for example, when the entire end face detector capable of detecting positive and negative values is initially moved, the stable detection region is preferably within a predetermined range before and after the neutral point of measurement.

According to this structure, the detection value obtained by the initial movement and having the error in the stable detection area within the allowable range is used as the movement correction value in the rotational axis direction of the profile measuring instrument of the three-dimensional cam. Is added to the predetermined amount of movement (the amount of movement to the measurement position determined when designing the three-dimensional cam, etc.) for moving the profile measuring instrument to the actual measurement position. As a result, it is possible to always measure the profile of the three-dimensional cam at a desired position based on the end face position. In addition, since the reference value for the measurement of the profile measuring instrument is determined by using the detection value with the error within the stable detection area within the allowable range as the movement correction value, strict zero point movement control is performed at the time of initial movement. There is no need, and while simplifying the control system and the drive system, the measurement position of the profile measuring instrument can be accurately fixed and the cam profile can be measured at the accurate position.

In order to achieve the above object, the present invention provides a three-dimensional cam having a cam surface with which a cam follower abuts, and the cam profile of the cam surface continuously changes in the rotational axis direction. A three-dimensional cam profile measuring device for measuring a cam profile, the profile measuring instrument having a measuring element for measuring the profile of the three-dimensional cam, and the three-dimensional cam for determining the position of the profile measurement by the profile measuring instrument. An end face detector having a detector for detecting the reference position of the end face in the rotation axis direction,
A movement control unit that integrally moves the profile measuring device and the end face detector in the rotation axis direction of the three-dimensional cam, wherein the movement control unit faces the end surface of the three-dimensional cam in the rotation axis direction. After the detector of the end face detector comes into contact with the end face, it is initially moved until it moves to a stable detection region where the detection value of the end face detector is stable, and the detection value in the stable detection region obtained at this time Is a movement correction value of the profile measuring instrument of the three-dimensional cam in the rotation axis direction, which is added to the predetermined movement amount from the end face of the profile measuring instrument.

According to this structure, the profile of the three-dimensional cam can be measured at a desired position based on the end face position. In addition, in order to determine the reference position for measurement of the profile measuring instrument, it is not necessary to perform strict zero point movement control at the time of initial movement, which simplifies the control system and drive system and fixes the measurement position of the profile measuring instrument. Can be performed accurately and a cam profile measurement at an accurate position can be performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings.

FIG. 1 shows a conceptual block diagram of a three-dimensional cam profile measuring apparatus 10 of this embodiment. The three-dimensional cam profile measuring device 10 includes a profile measuring device 14 for actually measuring the profile of the three-dimensional cam 12 and an end face detector 16 integrally formed with the profile measuring device 14 or individually formed and then integrated. The profile measuring device 14 and the end face detector 16 are composed of, for example, a step motor 18a for moving the profile measuring device 14 and the end face detector 16 in the left-right direction along the rotary shaft 12a of the three-dimensional cam 12 and a ball screw 18b rotationally driven by the step motor 18a. And a control unit (CPU) 20 for controlling the profile measuring device 14, the end face detector 16, the step motor 18a and the like, and controlling the entire three-dimensional cam profile measuring device 10 such as measuring operation. . The control unit 20 may be, for example, a control unit that individually controls the profile measuring device 14, the end face detector 16, the step motor 18a, and the like, for example, a profile measurement control unit (measurement process, display process, data process, output process, etc.). ), End face detection processing section (including measurement processing, display processing, data processing, output processing, etc.), movement control section (movement data processing, drive processing, etc.)
Etc.

In the present embodiment, the characteristic feature is that the end face detector 1 for accurately and easily determining the measurement position by the profile measuring device 14 from the end face position of the three-dimensional cam.
6 is provided, and the measurement position of the profile measuring device 14 is being corrected based on the detection result of the end face detector 16.

FIG. 2 shows only the end face detector 16. The end face detector 16 is of a type in which the detector 16a swings in the left-right direction in the figure (for example, a positive / negative value can be detected), as indicated by a chain line. FIG. 3 shows the relationship between the output signal based on the movement of the detector 16a of this type of oscillating detector and the actual movement amount of the detector 16a. As is clear from the figure, in the region where a predetermined load is applied, that is, in the vicinity of the neutral value of the measurable range where the measured value becomes ± 0, the output signal of the detector 16a and the actual movement amount are proportional ( It can be seen that the range is indicated by a double-headed arrow in the figure). On the contrary, it can be seen that the proportional relationship collapses as the measured value shifts in the negative or positive direction. In the present embodiment, a range indicated by a double-headed arrow in the figure is referred to as a stable detection area A. The stable detection area A is a range in which the measurement error of the detector 16a is small, and the detection error by the detector 16a of the end face detector 16 has been confirmed in advance by experiments or the like, and the influence based on the error is the three-dimensional cam. Is within an allowable range in which the can be operated within the allowable operating range. In the present embodiment, the stable detection area A is, for example, a range of ± 0.1 mm with 0 at the center.

Hereinafter, using the configuration of the three-dimensional cam profile measuring device 10 of FIG. 1 and the flowchart of FIG. 4,
A three-dimensional cam profile measuring method will be described. In the case of FIG. 1, the detector 16a of the end face detector 16 faces the end face 22 as shown by the one-dot chain line in FIG. 2 in the unloaded state, that is, in the state where it is not in contact with the end face 22 of the three-dimensional cam 12. The output signal of the end face detector 16 at that time is, for example, +10 mm. Moreover, in the configuration of FIG.
A moving body in which the 4 and the end face detector 16 are integrated is collectively referred to as a measurement unit 24. Further, in the present embodiment, the probe 14a of the profile measuring instrument 14 and the probe 16a of the end face detector 16 do not interfere with the three-dimensional cam 12 or the like during non-operation (non-measuring, non-detecting). Further, it is assumed that it is possible to retract from the operating position (for example, move upward or in the axial rotation direction of the ball screw 18b).

First, the measuring unit 24 is moved to the origin position (S100). Here, the origin position is a position where the measuring unit 24 is largely retracted to the right of the ball screw 18b with respect to the three-dimensional cam 12 in FIG. In this retracted position, the stylus 1 of the profile measuring instrument 14
4a and the detector 16a of the end face detector 16 are retracted to the non-operating position. Then, by turning on a measurement start switch or the like (not shown), the detector 16a moves to the operating position (see FIG.
And the CPU2.
0 drives the step motor 18a to move the measuring unit 24 closer to the three-dimensional cam 12 (S101). The approaching amount at this time is based on the set position of the three-dimensional cam 12 in advance, and the detector 16a and the end surface 22 are in contact with each other.
6a is the amount of movement in the vicinity of the neutral point, in the case of FIG. 1, to the position where the central axis of the detector 16a becomes substantially parallel to the end face 22. Then, at this time, the measurement reference plane position α (display position) detected by the end face detector 16 is measured (S102).

Then, the CPU 20 determines (α ≦ | A |) whether or not the measured value of α is the preset value, that is, the stable detection area A in FIG. 3 (S10).
3). Here, as described above, the stable detection area A (set value) is the allowable measurement range of the profile measurement position in the three-dimensional cam 12 in which the detection error due to the detector 16a of the end face detector 16 has been confirmed in advance by experiments or the like. Within the range, that is, in a range where an error during profile measurement does not affect the operation of the three-dimensional cam. In the case of this embodiment, for example, A =
± 0.1 mm. Further, as described above, in the case of FIG. 1, the detector 16a of the end face detector 16 is in an unloaded state,
Since it is largely tilted toward the end face 22 and the display is a positive display, the display value becomes smaller as the measuring unit 24 moves to the left. (S10
3) when α ≦ | A | is not satisfied, that is, the measurement unit 2
If the detection operation of the end face detector 16 performed by the movement of 4 is not yet performed in the stable detection area A, the measurement unit 24 is further moved at a predetermined speed (a speed at which the measurement unit 24 can be immediately stopped when a movement stop command is issued). Move to the left (S10
4) In (S103), it is further determined whether or not α ≦ | A |. That is, the measurement unit 24 constantly moves (S103) while moving linearly (initial movement) at a predetermined speed.
Will be determined.

If α ≦ │A│ in (S103), the CPU 20 stops the measuring unit 24. That is, the CPU 20 outputs a stop signal to the step motor 18a (S105). And further, CPU
In No. 20, after the stop signal is output, the display of the end face detector 16 is -A≤
It is confirmed whether or not α has been reached (S106). As described above, the measuring unit 24 is moved to the left at a predetermined speed at which it can be stopped immediately when a movement stop command is issued. However, the signal response of the step motor 18a, the inertia of the measuring unit 24, etc. By measuring unit 2
4 may exceed the stability detection area A and overrun. As shown in FIG. 3, in portions other than the stable detection area A, the measurement reliability of the end face detector 16 is reduced. In this case, it is necessary to slightly rotate the step motor 18a in the reverse direction to return the detector 16a to the stable detection area A.
Since it is necessary to perform delicate control including backlash of 8b with high accuracy, the control system and drive system become complicated. for that reason,
When −A ≦ α is not satisfied, that is, when the overrun has occurred, the process returns to (S100) and the end face detection operation is performed again.

On the other hand, even after the measuring unit 24 is stopped, -A
If ≦ α, the CPU 20 calculates the final movement amount S of the measuring unit 24 in order to move the tracing stylus 14a of the profile measuring instrument 14 to a predetermined position for actually measuring the profile (S107).

The final movement amount S can be obtained by S = γ- (β-α). Where β is the profile measuring device 1
4 is the distance from the measuring point (center axis) of the measuring element 14a to the measuring point of the detecting element 16a (the abutting tip of the detecting element 16a) when the measured value of the end face detector 16 is "0", 3
It is a value peculiar to the device, which is known at the design stage of the three-dimensional cam profile measuring device 10, and is 100 mm, for example. Also,
γ is a profile measurement position that is predetermined based on the specifications of the three-dimensional cam and is, for example, 20 mm. For example, when the display of the end face detector 16 after the measurement unit 24 is stopped is "0.07", the final movement amount S for moving the tracing stylus 14a to the correct γ position is S = γ- (β −
α) = 20− (100−0.07) = − 79.93 mm
Becomes That is, -7 from the stop of the measurement unit 24
If the 9.93 mm measuring unit 24 is moved,
4a can be moved to the correct γ position. In addition,
At this time, since the end face detection is performed within the stable detection area A, the position reliability of the measurement unit 24 is very high.

By the way, S = −79.93 mm means that the measuring unit 24 is moved from right to left in FIG. 1 when the end face is detected, whereas it is moved from left to right. Usually, in the case of the moving mechanism using the ball screw 18b or the like, since backlash exists, an error corresponding to the backlash occurs when the moving direction is reversed. Since the backlash can be measured at the design stage of the three-dimensional cam profile measuring apparatus 10, the final movement is performed in the opposite direction by correcting the control value output from the CPU 20 to the step motor 18a for the final movement by this value. Can also perform the actual movement accurately. Therefore, first, it is determined whether or not 0 ≦ S, that is, whether or not the final movement of the measurement unit 24 involves reverse rotation (S108). If 0 ≦ S is not satisfied, the CPU 20 determines that the final movement involves a backward movement, and the CPU 20 corrects the control value output to the step motor 18a based on the backlash amount (S109). In the case of FIG. 1, the CPU
20 increases the control amount of the step motor 18a by the amount of backlash.

Then, the CPU 20 stores the detector 16a of the end face detector 16 in the retracted position when it is not in operation, and then moves the measurement unit 24 by adding the detection value of the end face detector 16 as a movement correction amount S. Then, it is moved based on the control amount for which the backlash correction is performed (S110).

After that, when it is confirmed that the final movement of the measuring unit 24 is completed (fixing to the measuring position is completed), the tracing stylus 14a of the profile measuring instrument 14 is projected to the operating position.
After contacting the cam surface of the three-dimensional cam 12, the three-dimensional cam 12
Is rotated to start the actual profile measurement (S11
1). Further, in (S108), if 0 ≦ S, that is, if the final movement does not accompany the movement of the measurement unit 24 in the opposite direction, the CPU 20 does not perform the backlash correction and sets the detector 16a of the end face detector 16 to The measurement unit 24 is stored in the retracted position when it is not operating, and then the measurement unit 24 is moved based on the control amount in which the detection value of the end face detector 16 is added as the movement correction amount (S110), and the profile measurement is started (S111).

As described above, according to this embodiment, the end face of the three-dimensional cam 12 is detected prior to the profile measurement, and the tracing stylus 14a of the profile measuring instrument 14 is moved based on the detection result. The tracing stylus 14a can be accurately moved to the profile measuring position of the cam 12. The end face detection by the end face detector 16 is
Rather than moving the detector 16a of the end face detector 16 to the "0 position" accurately and setting it as the reference position (end face position), the detector 16a should be placed in the stable detection area A where an error can be allowed. Since only the control is performed, it is not necessary to perform the strict zero point movement control, the control system and the drive system are simplified, and the measurement position of the profile measuring instrument 14 is accurately fixed to measure the cam profile at the accurate position. It can be carried out.

Further, the configuration described in the present embodiment is an example, and the end face detection of the three-dimensional cam is performed within the stable measurement range prior to the profile measurement, and the actual profile measurement position is determined in consideration of the detected value. As long as the configuration is determined, the device configuration can be appropriately changed, and the same effect as this embodiment can be obtained.

[0027]

According to the present invention, the detection value obtained by the initial movement and having the error within the stable detection area within the allowable range is corrected by the movement of the profile measuring instrument of the three-dimensional cam in the rotation axis direction. As a value, the reference position for measurement by the profile measuring instrument is determined. Therefore, it is possible to always measure the profile of the three-dimensional cam at a desired position based on the end face position. In addition, since the reference value for the measurement of the profile measuring instrument is determined by using the detection value with the error within the stable detection area within the allowable range as the movement correction value, strict zero point movement control is performed at the time of initial movement. There is no need, and while simplifying the control system and the drive system, the measurement position of the profile measuring instrument can be accurately fixed and the cam profile can be measured at the accurate position.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a conceptual configuration of a three-dimensional cam profile measuring device according to an embodiment of the present invention.

FIG. 2 is a conceptual enlarged view of an end face detector of the three-dimensional cam profile measuring device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a relationship between an output signal based on the movement of the detector of the oscillating detector and an actual movement amount of the detector.

FIG. 4 is a flowchart illustrating an operation of the three-dimensional cam profile measuring device according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a conceptual configuration of a conventional three-dimensional cam profile measuring device.

[Explanation of symbols]

10 3 dimensional cam profile measuring device, 12 3 dimensional cam, 12a rotating shaft, 14 profile measuring device, 1
4a measuring element, 16 end face detector, 16a detecting element, 1
8a Step motor, 18b Ball screw, 20 C
PU, 22 end face, 24 measuring unit.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F062 AA61 BC32 EE01 EE25 EE62                       FF03 GG17 MM03                 2F069 AA66 BB40 GG01 GG59 JJ17                       MM04 MM32                 3G016 BA35 DA27 GA01                 3J030 EB00

Claims (3)

[Claims] 1. A cam surface with which a cam follower abuts,
In a cam profile measuring method for a three-dimensional cam in which a cam profile of the cam surface continuously changes with respect to a rotation axis direction, a whole end face detector including a detector is directed toward an end face in the rotation axis direction of the three-dimensional cam. In the step of moving, the step of initially moving the whole end face detector until the detector contacts the end face and moves to a stable detection region where the detection value of the end face detector is stable, and the initial movement A step of adding the detected value obtained in the stable detection area to a predetermined movement amount from the end face of the profile measuring device as a movement correction value of the profile measuring device of the three-dimensional cam in the rotation axis direction; Fixing the profile measuring device at the specified position and rotating the three-dimensional cam about the rotation axis to measure the cam profile of the three-dimensional cam. A three-dimensional cam profile measuring method to be used. 2. The three-dimensional cam profile measuring method according to claim 1, wherein, when the entire end face detector is initially moved, the stable detection area is within a predetermined range before and after a measurement neutral point. . 3. A cam surface with which a cam follower abuts,
A three-dimensional cam profile measuring device for measuring a cam profile of a three-dimensional cam in which a cam profile of the cam surface continuously changes with respect to a rotation axis direction, the profile measurement having a probe for measuring the profile of the three-dimensional cam. And an end face detector having a detector for detecting a reference position of an end face in the rotation axis direction of the three-dimensional cam for determining the position of profile measurement by the profile measurer, the profile measurer and the end face detector And a movement control unit for integrally moving the three-dimensional cam in the rotation axis direction of the three-dimensional cam, wherein the movement control unit is a detector of the end face detector toward the end surface of the three-dimensional cam in the rotation axis direction. After abutting against the end face, it is initially moved until it moves to a stable detection region where the detection value of the end face detector is stable, and the stable detection region obtained at this time In as the moving correction value for the rotational axis of the profile measuring instrument detection values 3D cam, 3D cam profile measuring apparatus, characterized by adding a predetermined amount of movement from the end face of the profile measuring instrument.