Cam measuring device and method based on laser interference principle
阅读说明：本技术 一种基于激光干涉原理的凸轮测量装置及测量方法 (Cam measuring device and method based on laser interference principle ) 是由 林虎 薛梓 *** 杨武伟 于 2020-07-20 设计创作，主要内容包括：本发明公开的一种基于激光干涉原理的凸轮测量装置及测量方法,包括测微测头、XZ轴运动装置、激光器；测微测头安装在XZ轴运动装置上,沿X轴或Z轴移动；测微测头的测球与凸轮表面相接触；激光器发出激光干涉测长双光路,包括激光光束通过分光镜被分为X光路和Z光路；X光路经过平面镜反射后被角锥镜一接收,角锥镜一接收的反射后X光路与测杆的轴向相平行；Z光路被角锥镜二接收,角锥镜二接收的反射后Z光路与测杆的轴向相垂直；角锥镜一和角锥镜二均设置在测微测头的测杆上。本发明采用激光干涉测长作为测量标准,替代光栅尺测长,大大降低了测量过程的阿贝误差,同时光路的布置适用于多种类型凸轮的测量。(The invention discloses a cam measuring device and a cam measuring method based on a laser interference principle, which comprise a micrometer measuring head, an XZ axis movement device and a laser; the micrometer measuring head is arranged on the XZ axis movement device and moves along the X axis or the Z axis; the measuring ball of the micrometer measuring head is contacted with the cam surface; the laser device emits laser interference length measurement double light paths, wherein laser beams are divided into an X light path and a Z light path through a spectroscope; the X light path is received by the pyramid mirror after being reflected by the plane mirror, and the reflected X light path received by the pyramid mirror is parallel to the axial direction of the measuring rod; the Z light path is received by the second pyramid mirror, and the reflected Z light path received by the second pyramid mirror is vertical to the axial direction of the measuring rod; the first angle cone mirror and the second angle cone mirror are both arranged on a measuring rod of the micrometer measuring head. The invention adopts laser interference length measurement as a measurement standard to replace a grating ruler to measure the length, thereby greatly reducing the Abbe error in the measurement process, and meanwhile, the arrangement of the optical path is suitable for the measurement of various types of cams.)
1. A cam measuring device based on a laser interference principle is characterized by comprising a micrometer measuring head, an XZ axis moving device and a laser, wherein a cam is positioned on a cam shaft and is driven by the cam shaft to do rotary circular motion; wherein the content of the first and second substances,
the micrometer measuring head is arranged on the XZ axis movement device and moves along an X axis or a Z axis; the micrometer measuring head comprises a measuring rod and a measuring ball positioned at the front end of the measuring rod, and the measuring ball is in contact with the surface of the cam;
the laser device emits laser interference length measurement double light paths, and laser beams are divided into an X light path and a Z light path through the spectroscope; the X light path is received by the first pyramid mirror after being reflected by the plane mirror, and the reflected X light path received by the first pyramid mirror is parallel to the axial direction of the measuring rod; the Z light path is received by a second pyramid mirror, and the reflected Z light path received by the second pyramid mirror is vertical to the axial direction of the measuring rod; the first angle cone mirror and the second angle cone mirror are both arranged on the measuring rod.
2. The cam measuring device based on the laser interference principle according to claim 1, wherein the XZ-axis moving device comprises an X-axis guide rail, an X-axis slide block connected with the X-axis guide rail in a sliding manner, a Z-axis guide rail and a Z-axis slide block connected with the Z-axis guide rail in a sliding manner; the X-axis guide rail is arranged on the Z-axis sliding block; the micrometer measuring head is arranged on the X-axis sliding block.
3. The cam measuring device based on the laser interference principle according to claim 2, wherein the micrometer head further comprises a head base, the head base is mounted on the X-axis slide block, and the measuring rod is mounted on the head base.
4. The cam measuring device based on the laser interference principle as claimed in claim 1, wherein the X-ray path split by the beam splitter passes through a first plane mirror and a second plane mirror in sequence and then enters the first angle cone mirror, and the incident light paths of the first plane mirror and the second plane mirror are both reflected by 90 °.
5. The laser interferometry based cam measurement device of claim 1 wherein said cam comprises a disc cam, and said ball is in contact with a side surface of said disc cam.
6. The cam measuring device based on the laser interference principle as claimed in claim 1, wherein the cam comprises a cylindrical cam, a curved groove is formed in the cylindrical cam, and the measuring ball is in contact with the lower end face and the inner bottom face of the curved groove.
7. A method for measuring a cam measuring device based on the laser interference principle according to claim 1, comprising the steps of:
arranging an XZ axis motion device and a micrometer measuring head on one side of the camshaft, and constructing a laser interference length measuring double light path;
clearing laser measured values in the X-axis direction and the Z-axis direction, and driving a micrometer measuring head to contact with the surface of the cam by an XZ-axis motion device;
thirdly, the camshaft makes a rotary circular motion under the drive of a rotary shaft system, the XZ shaft motion device drives the micrometer measuring head to perform touch measurement to the surface of the cam, and the length measuring value l of the current laser is acquired at every N degreesiAnd the angle value theta of the rotary shaft systemiUntil the cam rotates one turn;
step four, obtaining a laser length measuring value and a rotation shafting angle value sequence (l) after the measurement is finishedi,θi)，
8. A measuring method according to claim 7, wherein during the three-step camshaft revolution, the XZ axis movement device is controlled to move along the X axis or along the Z axis according to the offset value of the measuring rod so as to maintain the micrometer head in contact with the cam surface.
9. A measuring method according to claim 8, characterized in that the XZ-axis moving device moves along the X-axis to the cam surface to perform the measuring process for the disc cam; obtaining the maximum value l of the laser length measuring value according to the laser length measuring value and the rotation shafting angle value sequencemaxCalculating to obtain a corresponding lift value sequence (l) of the disc cammax-li,θi)。
10. A measuring method according to claim 8, characterized in that the XZ-axis moving device moves along the Z-axis to the cam surface to perform the measuring process for the cylindrical cam; obtaining the minimum value l of the laser length measuring value according to the laser length measuring value and the rotation shafting angle value sequenceminAnd calculating to obtain a corresponding lift value sequence (l) of the cylindrical cami-lmin,θi)。
Technical Field
The invention belongs to the technical field of precision measurement, and relates to a cam measuring device and a cam measuring method based on a laser interference principle.
Background
The camshaft belongs to a valve actuating mechanism of an engine, and the lift error of the camshaft directly influences the size of the opening and closing clearance of the valve and the valve actuating efficiency and is also one of the influencing factors of the noise of the engine. At present, the cam measuring method mainly depends on a polar coordinate measuring principle, namely, a precision spindle system and a high-precision grating encoder generate a circle scale of a measured cam rotation angle, a radial precision guide rail and a long grating sensor scan a cam peach surface in a radial direction, and finally, a measuring software calculates an error value of a cam parameter. In the instrument, the grating ruler is used as a length measuring unit of each coordinate axis and a feedback control unit of the motion of each coordinate axis, is generally distributed near an X, Y, Z guide rail and far away from a measured point of the cam, and a certain angular pendulum error exists in the guide rail, so that a larger Abbe error is generated, and the measuring precision of the cam is greatly reduced. Meanwhile, for the measurement of a plurality of error items of the cam, the existing measurement principle cannot avoid the displacement influence between measurement light paths for the measurement of the lift values of different cams, so that the method cannot be applied to the measurement of various cams.
Therefore, it is an urgent technical problem to be solved by those skilled in the art to provide a cam measuring apparatus and a cam measuring method based on the laser interference principle, which can improve the measuring accuracy of a cam and is suitable for measuring various cams.
Disclosure of Invention
In order to achieve the purpose, the invention provides a cam measuring device and a cam measuring method based on a laser interference principle, wherein laser interference length measurement is adopted as a measuring standard to replace a grating ruler length measurement, a laser interference length measurement optical path is arranged near a measured point of a cam, the Abbe error in the measuring process is greatly reduced, and meanwhile, the arrangement of the optical path is suitable for measuring various types of cams. The specific scheme for achieving the purpose is as follows:
a cam measuring device based on a laser interference principle is characterized in that a cam is positioned on a cam shaft and is driven by the cam shaft to do rotary circular motion, and the cam measuring device comprises a micrometer measuring head, an XZ shaft motion device and a laser; wherein the content of the first and second substances,
the micrometer measuring head is arranged on the XZ axis movement device and moves along an X axis or a Z axis; the micrometer measuring head comprises a measuring rod and a measuring ball positioned at the front end of the measuring rod, and the measuring ball is in contact with the surface of the cam;
the laser device emits laser interference length measurement double light paths, and laser beams are divided into an X light path and a Z light path through the spectroscope; the X light path is received by the first pyramid mirror after being reflected by the plane mirror, and the reflected X light path received by the first pyramid mirror is parallel to the axial direction of the measuring rod; the Z light path is received by a second pyramid mirror, and the reflected Z light path received by the second pyramid mirror is vertical to the axial direction of the measuring rod; the first angle cone mirror and the second angle cone mirror are both arranged on the measuring rod.
Preferably, the XZ-axis movement device comprises an X-axis guide rail, an X-axis sliding block connected with the X-axis guide rail in a sliding manner, a Z-axis guide rail and a Z-axis sliding block connected with the Z-axis guide rail in a sliding manner; the X-axis guide rail is arranged on the Z-axis sliding block; the micrometer measuring head is arranged on the X-axis sliding block.
Preferably, the micrometer measuring head further comprises a measuring head seat, the measuring head seat is mounted on the X-axis slide block, and the measuring rod is mounted on the measuring head seat.
Preferably, the X light path split by the beam splitter passes through the first plane mirror and the second plane mirror in sequence and then is incident to the first pyramid mirror, and the incident light paths of the first plane mirror and the second plane mirror are reflected by 90 degrees.
Preferably, the cam comprises a disc cam, and the ball is in contact with a side surface of the disc cam.
Preferably, the cam comprises a cylindrical cam, a curved groove is formed in the cylindrical cam, and the measuring ball is in contact with the lower end face and the inner bottom face of the curved groove.
The invention also provides a measuring method of the cam measuring device based on the laser interference principle, which comprises the following steps:
arranging an XZ axis motion device and a micrometer measuring head on one side of the camshaft, and constructing a laser interference length measuring double light path;
clearing laser measured values in the X-axis direction and the Z-axis direction, and driving a micrometer measuring head to contact with the surface of the cam by an XZ-axis motion device;
thirdly, the camshaft makes a rotary circular motion under the drive of a rotary shaft system, the XZ shaft motion device drives the micrometer measuring head to perform touch measurement to the surface of the cam, and the length measuring value l of the current laser is acquired at every N degreesiAnd the angle value theta of the rotary shaft systemiUntil the cam rotates one turn;
step four, obtaining a laser length measuring value and a rotation shafting angle value sequence after the measurement is finished
Preferably, during the rotation of the three-step camshaft, the XZ axis motion device is controlled to move along the X axis or move along the Z axis according to the offset value of the measuring rod, so as to maintain the micrometer measuring head in contact with the cam surface.
Preferably, the XZ-axis motion device moves along the X axis to the cam surface to perform a measuring process for the disc cam; obtaining the maximum value l of the laser length measuring value according to the laser length measuring value and the rotation shafting angle value sequencemaxCalculating to obtain a corresponding lift value sequence (l) of the disc cammax-li,θi)。
Preferably, the XZ-axis motion device moves along the Z axis to the cam surface to perform a contact measurement process for the cylindrical cam; obtaining the minimum value l of the laser length measuring value according to the laser length measuring value and the rotation shafting angle value sequenceminAnd calculating to obtain a corresponding lift value sequence (l) of the cylindrical cami-lmin,θi)。
Compared with the prior art, the invention has the following beneficial effects:
by designing and arranging the laser interference length measuring light path, the laser interference length measuring light path is adopted as a measuring standard to replace a grating ruler to measure the length, and the laser interference length measuring light path is arranged near a measured point of the cam, so that the Abbe error in the measuring process is greatly reduced. The invention can realize the measurement of a plurality of error items of the cam by designing the improved X, Z laser interference length measurement double light paths, and in the measurement process, the X laser interference length measurement light path is always along the rotation center of the measured cam and is consistent with the motion path of the driven part when the cam is actually used. Similarly, the Z laser interference length measuring light path is always parallel to the rotation axis of the measured cylindrical cam and is consistent with the motion path of the driven member when the cam is actually used, so that the measurement result not only can calculate the geometric error of the measured cam, but also can directly reflect the motion displacement error of the cam driven member. And the independence among different light paths is strong, the lift value measuring process of different cams cannot be influenced by the displacement among the measuring light paths, and the method is suitable for measuring various cams.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only embodiments of the invention, and that for a person skilled in the art, other drawings can be obtained from the provided drawings without inventive effort.
FIG. 1 is a schematic diagram of a cam measuring device based on the laser interference principle according to an embodiment of the present invention;
FIG. 2 is a top view of a cam measuring device based on the laser interference principle according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a cam measuring device based on a laser interference principle according to a second embodiment of the present invention.
In the figure:
1 is a cam; 2 is a rotary shaft system; 3 is a laser; 4 is a spectroscope; 5 is a pyramid second; 6 is a micrometer measuring head; 7 is a plane mirror I; 8 is a plane mirror II; 9 is a pyramid mirror I; 10 is a Z-axis slide block; 11 is an X-axis slide block; 12 is a camshaft; 13 is an X-axis guide rail; 14 is a Z-axis guide rail; 15 is a measuring head seat; 16 is a measuring rod; 17 is a measuring ball; 18 are curved slots.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention discloses a cam measuring device based on a laser interference principle, wherein a cam 1 is positioned on a cam shaft 12 and rotates and circularly moves under the driving of the cam shaft 12, and comprises a micrometer measuring head 6, an XZ shaft moving device and a laser 3; the micrometer measuring head 6 is arranged on the XZ axis movement device and moves along the X axis or the Z axis; the micrometer measuring head 6 comprises a measuring rod 16 and a measuring ball 17 positioned at the front end of the measuring rod 16, and the measuring ball 17 is contacted with the surface of the cam 1; the laser 3 emits laser interference length measurement double light paths, wherein laser beams are divided into an X light path and a Z light path through the
In order to further optimize the technical scheme, the XZ-axis movement device comprises an X-axis guide rail 13, an X-axis slide block 11 connected with the X-axis guide rail 13 in a sliding manner, a Z-axis guide rail 14 and a Z-axis slide block 10 connected with the Z-axis guide rail 14 in a sliding manner; the X-axis guide rail 13 is arranged on the Z-axis slide block 10; the micrometer head 6 is mounted on the X-axis slide block 11. The micrometer measuring head 6 further comprises a measuring head seat 15, the measuring head seat 15 is installed on the X-axis sliding block 11, and the measuring rod 16 is installed on the measuring head seat 15.
In order to further optimize the technical scheme, the X-ray path split by the
The XZ-axis movement device drives the micrometer measuring head 6 to move along the X axial direction or move along the Z axial direction according to different types of cams, wherein for the disc-shaped cam 1, the measuring ball 17 is in contact with the side surface of the disc-shaped cam 1, and an X light path is started to measure the length of the cam. For the cylindrical cam 1, a
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