Measuring device and method for detecting lift of cam shaft cam

Abstract

The invention relates to the technical field of camshaft detection, and provides a measuring device and method for detecting the cam lift of a camshaft, and the cam lift of an exhaust cam is measured by using an angle lift determination method. Measuring the cam lift of the air inlet cam by using a lift angle determination method; and the cam lift of the fuel cam is measured by using a lift angle determination method, so that the detection precision is improved, and the detection efficiency is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of camshaft detection, and in particular to a measuring device and method for detecting cam lift of a camshaft. Background Art

[0002] The statements in this section merely provide background technical information related to the present application and do not necessarily constitute prior art.

[0003] The camshaft is one of the key components of a diesel engine. Its function is to control the opening and closing of the valve. When the diesel engine is working, the camshaft rotates at a high speed and needs to withstand a large torque. Therefore, the design has high requirements for the strength and support of the camshaft. The cam lift and cam angle of the camshaft are related to the power and operating characteristics of a diesel engine, and directly affect the valve timing angle, injection advance angle and fuel injection condition of the diesel engine. Therefore, the detection of the cam lift of the camshaft is very important and indispensable. The structures of the cams on the camshaft are different, but in the prior art, when detecting the camshaft, most of them use temporary fixtures to clamp the camshaft, and each cam follows a detection method, which has low detection efficiency and large detection errors. Summary of the invention

[0004] In order to solve the problems in the background technology, the present application proposes a measuring device and method for detecting the cam lift of a camshaft.

[0005] The present application provides a measuring device for detecting the cam lift of a camshaft, comprising: an optical indexing angle meter, a tailstock, a cam lift reading device, and a zero position calibration spindle;

[0006] The optical indexing angle meter and tailstock are used to clamp the camshaft. The optical indexing angle meter is also used to measure the rotation angle of the camshaft. The tailstock can move linearly along the XX direction.

[0007] The cam lift reading device is used to complete the reading measurement of the cam lift in the YY direction;

[0008] The zero position calibration spindle is used to complete the calibration of the cam lift measuring instrument with equal height and equal distance in the YY direction.

[0009] Preferably, the optical indexing angle meter is provided with a large top on one side of the X direction, an angle display screen is provided on the top, and a rotating handle is provided on one side of the Y direction;

[0010] A small center is provided on one side of the tailstock in the X direction, and a small center moving handle is provided on the symmetrical side thereof;

[0011] The cam lift reading device is provided with a lift moving shaft on one side in the Y direction, a measuring head is provided at the front end of the lift moving shaft, a set screw is provided on one side in the X direction, and a lift display screen is provided on the top.

[0012] Preferably, a special clamp is also included, which includes two flanges arranged in parallel and connected, and a first clamping bolt and a clamping mechanism are arranged on the outer periphery of the flange, and the first clamping bolt spirally penetrates the side wall of the flange, and the clamping mechanism includes a flange joint and a second clamping bolt, and the flange joint includes two convex plates arranged in parallel on the outer periphery of the flange, and the second clamping bolt penetrates one of the convex plates and is spirally connected to the other one.

[0013] Preferably, the measuring head is marked with a center line.

[0014] The present application also provides a method for measuring the cam lift of a camshaft. Based on the measuring device described above, the specific steps are as follows:

[0015] S100: Align the center line of the measuring device;

[0016] S200: equidistant calibration of the center line YY direction of the measuring device;

[0017] S300: performing circular runout error detection on the base circle of the camshaft cam;

[0018] S400: measuring the cam lift of the exhaust cam by using an angle-determined lift method;

[0019] S500: measuring the cam lift of the intake cam by using a lift determination angle method;

[0020] S600: Measuring the cam lift of the fuel cam by using the lift determination angle method.

[0021] Preferably, in step S100, the specific method for aligning the center line of the measuring device is as follows:

[0022] Install the zero-position calibration mandrel on the large center and the small center, turn the small center moving handle 9 to complete the installation and fixation, install the height vernier caliper with the lever micrometer and place it on one side of the zero-position calibration mandrel, measure the upper generatrix of the zero-position calibration mandrel, and take data at the left, middle and right positions in the XX direction to ensure that the parallelism error between the zero-position calibration center and the placement platform is less than 0.01mm;

[0023] In step S200, the specific method for calibrating the center line YY direction of the measuring device is as follows:

[0024] Loosen the set screw of the cam lift reading device to make the measuring head on the lift moving shaft contact the front measuring generatrix of the zero position calibration spindle, take readings at the left, middle and right positions of the center line of the zero position calibration spindle in the YY direction, and observe that the maximum and minimum values ​​of the readings on the lift display screen should be less than 0.01mm.

[0025] Preferably, in step S300, the specific method for detecting the circular runout error of the base circle of the camshaft cam is as follows:

[0026] Loosen the set screws of the cam lift reading device, make the measuring head contact the exhaust cam base circle, intake cam base circle and fuel cam base circle of the camshaft respectively, rotate the camshaft, and confirm that the maximum and minimum readings on the lift display screen are less than 0.01mm.

[0027] Preferably, in step S400, the specific method of measuring the cam lift of the exhaust cam using the angle-determined lift method is as follows:

[0028] S401: Loosen the set screw of the cam lift reading device to make the measuring head contact with the exhaust cam base circle point of the camshaft. At this time, the lift display screen of the cam lift reading device shows the cam base circle lift reading at this point, which is set to e1;

[0029] S402: query and obtain the theoretical lift value of angle a1 as l 1, rotate the camshaft in a clockwise direction, and when the lift reading on the lift display screen is e1+l 1, record the lift angle on the angle display screen at this point and set it as m1;

[0030] S403: Continue to rotate the camshaft clockwise by an angle of a2 to the middle position of the left lift of the cam. At this time, the lift reading on the lift display is e2. At the same time, the lift angle on the angle display is recorded and set to m2, where 2*a1+a2=180°;

[0031] S404: Find out that the theoretical lift value of the left lift a1+a2 is l 2, then the theoretical lift difference between the right lift a1 and the left lift a1+a2 should be: l 1-l 2;

[0032] S405: Calculate the actual lift difference as: e1+1 1-e2. When e1+1 1-e2=1 1-1 2, execute step S406. Otherwise, jump to step S401 until e1+1 1-e2=1 1-1 2. Record the lift angles m1 and m2 of the two points on the angle display screen at this time. Use m1+90-a1 or m2-a2-90 to get the lobe angle f of the exhaust cam.

[0033] S406: f-90° is the starting point n of the exhaust cam, f+90° is the ending point n of the exhaust cam, the camshaft is continuously rotated clockwise to the ending point, the reading e3 on the lift display screen is recorded, the camshaft is continuously rotated clockwise to the starting point, the reading e4 on the lift display screen is recorded, and (e3+e4) / 2=e5 is calculated;

[0034] S407: e4-e5 is the actual lift value of the exhaust cam n at the beginning. Continue to rotate the camshaft 1° clockwise and record the reading e6 on the lift display. e6-e5 is the actual lift value of the exhaust cam 1°, and so on until the actual lift value is measured after the rotation completes 180°.

[0035] Preferably, in step S500, the specific method of measuring the cam lift of the intake cam using the lift determination angle method is:

[0036] S501: Loosen the set screw of the cam lift reading device to make the measuring head contact with the intake cam base circle point of the camshaft. At this time, the lift display screen of the cam lift reading device shows the cam base circle lift reading at this point, which is set to e1;

[0037] S502: Select a theoretical lift value of a certain angle b1 at the middle position of the right lift of the intake cam, set it as L, rotate the camshaft in a clockwise direction to the middle position of the right lift of the cam, and when the lift value on the lift display screen is e1+L, record the lift angle on the angle display screen as m1;

[0038] S503: Rotate the camshaft in a clockwise direction, and when the measuring head reaches the left lift position of the intake cam, find the lift point where the lift value on the lift display screen is e1+L, and record the lift angle on the angle display screen as m2;

[0039] S504: Calculate m1+m2 / 2=f, where f is the intake cam lobe position angle;

[0040] S505: f-85.5° is the starting point n of the intake cam, f°+90° is the ending point n of the intake cam, the camshaft is continuously rotated clockwise to the starting point n, the reading e3 on the lift display screen is recorded, the camshaft is continuously rotated clockwise to the ending point n, the reading e4 on the lift display screen is recorded, and (e3+e4) / 2=e5 is calculated;

[0041] S506: e4-e5 is the actual lift value at the beginning of the intake cam n. Continue to rotate the camshaft 1° clockwise and record the reading e6 on the lift display. e6-e5 is the actual lift value of the intake cam 1°, and so on, until the actual lift value of 171° is measured.

[0042] Preferably, in step S600, the specific method of measuring the cam lift of the fuel cam using the lift determination angle method is:

[0043] S601: Loosen the set screw of the cam lift reading device to make the measuring head contact with the gas cam base circle point of the camshaft. At this time, the lift display screen of the cam lift reading device shows the cam base circle lift reading at this point, which we set as e1;

[0044] S602: Take a theoretical lift value of an angle α on the right single-sided lift of the gas cam, set it as L, and then rotate the camshaft clockwise. When the lift value on the lift display screen is e1+L, record the lift angle on the angle display screen as m1;

[0045] S603: Calculate the angle of the fuel cam lobe on the angle display screen: f = m1 + (50.3° - α), then f - 50.3 is the starting point n of the gas cam, rotate the camshaft clockwise to the starting point n of the gas cam, and at this time record the lift reading on the lift display screen as e2;

[0046] S604: The actual lift value of the gas cam n at the beginning is equal to 0. Continue to rotate the camshaft clockwise by 1° and record the reading e3 on the lift display screen. Then e3-e2 is the actual lift value of the gas cam 1°, and so on, until the actual lift value of 251.8° is measured after the rotation is completed.

[0047] Compared with the prior art, the beneficial effects of this application are:

[0048] The measuring device of the present application stably clamps the camshaft through an optical dividing angle meter and a tailstock, and completes the calibration of the cam lift reading device center line equal height and equal distance in the YY direction through a zero-position calibration spindle, thereby improving the detection efficiency.

[0049] The present application uses different measurement methods to detect the cam lift according to the different structures of the exhaust cam, intake cam and fuel cam, thereby improving the detection accuracy and further improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0051] Figure 1 This is the cam lift and cam angle parameter table for the 230 diesel engine.

[0052] Figure 2 Schematic diagram of the camshaft structure.

[0053] Figure 3This is a schematic diagram of the cam lift reading device structure of this application.

[0054] Figure 4 This is a schematic diagram for the implementation of this application.

[0055] Figure 5 This is a schematic diagram of the fixture structure for this application.

[0056] Figure 6 This is a schematic diagram of the measuring head structure for this application.

[0057] Figure 7 Exhaust cam lift measurement flow chart for this application,

[0058] Figure 8 Intake cam lift measurement flow chart for this application,

[0059] Fig. 9 For this application, the fuel cam lift measurement flow chart is as follows:

[0060] Fig.10 This is a schematic diagram of the overall detection method flow of this application.

[0061] In the figure:

[0062] 100, optical indexing angle meter, 200, camshaft, 300, tailstock, 400, cam lift reading device, 500, special fixture, 600, zero position calibration spindle;

[0063] 1. Angle display screen, 2. Rotating handle, 3. Large center, 4. Measuring head, 5. Set screw, 6. Lift display screen, 7. Lift moving shaft, 8. Small center, 9. Small center moving handle, 201. Large end shaft diameter, 211. Large end center hole, 202. Exhaust cam, 203. Intake cam, 204. Fuel cam, 205. Small end shaft diameter, 251. Small end center hole, 41. Marking center line, 501. Flange, 502. First clamping bolt, 503. Second clamping bolt, 504. Flange joint. DETAILED DESCRIPTION

[0064] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0065] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0066] In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present disclosure, and do not specifically refer to any part or element in the present disclosure and should not be understood as limitations on the present disclosure.

[0067] Example 1

[0068] like Figures 1 to 10 As shown, the present application provides a measuring device for detecting the cam lift of a camshaft, comprising: an optical indexing angle meter 100, a tailstock 300, a cam lift reading device 400, and a zero position calibration spindle 600;

[0069] The optical indexing angle meter 100 and the tailstock 300 are used to clamp the camshaft 200. The optical indexing angle meter 100 is also used to measure the rotation angle of the camshaft 200. The tailstock 300 can move linearly along the XX direction.

[0070] The cam lift reading device 400 is used to complete the reading measurement of the cam lift in the YY direction;

[0071] The zero position calibration spindle 600 is used to complete the calibration of the cam lift reading device 400 with equal height of the center line and equal distance in the YY direction.

[0072] Specifically, a large center point 3 is provided on one side of the optical dividing angle meter 100 in the X direction, an angle display screen 1 is provided on the top thereof, and a rotating handle 2 is provided on one side of the Y direction. The rotating handle 2 is transmission-connected to the large center point 3. By rotating the rotating handle 2, the large center point 3 can be controlled to translate along the XX direction. The angle display screen 1 is used to display the rotation angle of the large center point 3.

[0073] A small center point 8 is provided on one side of the tailstock 300 in the X direction, and a small center point moving handle 9 is provided on the symmetrical side thereof. The small center point moving handle 9 is connected to the small center point 8 through an internal screw drive. The small center point moving handle 9 can be rotated to control the small center point 8 to translate along the XX direction.

[0074] A lift moving shaft 7 is arranged on one side of the cam lift reading device 400 in the Y direction, a measuring head 4 is arranged on the front end of the lift moving shaft 7, a set screw 5 is arranged on one side of the cam lift reading device 400 in the X direction, and a lift display screen 6 is arranged on the top of the cam lift reading device 400. The inner end of the set screw 5 is in contact with the lift moving shaft 7, and the lift moving shaft 7 can be fixed and released by rotating the set screw 5. The lift display screen 6 is used to display the stroke of the lift moving shaft 7 in the YY direction.

[0075] Specifically, it also includes a special clamp 500, which includes two flanges 501 arranged in parallel and connected, and a first clamping bolt 502 and a clamping mechanism are arranged on the outer periphery of the flange 501. The first clamping bolt 502 spirally penetrates the side wall of the flange 501, and the clamping mechanism includes a flange joint 504 and a second clamping bolt 503. The flange joint 504 includes two convex plates arranged in parallel on the outer periphery of the flange 501, and the second clamping bolt 503 penetrates one of the convex plates and is spirally connected to the other one.

[0076] The special clamp 500 is used to connect the camshaft 200 and the large center point 3 of the optical dividing angle meter 100. The two flanges 501 are respectively sleeved on the large end shaft diameter 201 and the large center point 3 of the camshaft 200. First, the second clamping bolt 503 is tightened to drive the two convex plates closer, so that the inner side of the flange 501 is tightly fitted with the large end shaft diameter 201 or the large center point 3, and then the first clamping bolt 502 is tightened to make it contact with the large end shaft diameter 201 or the large center point 3, thereby realizing the fixed connection between the camshaft 200 and the large center point 3 of the optical dividing angle meter 100.

[0077] Preferably, the measuring head 4 is marked with a center line 41, and the diameter of the measuring head 4 It should be consistent with the median tolerance of the roller diameter that contacts the camshaft in actual work and designed to be the theoretically correct size. The measuring head is fixed on the lift moving shaft 7.

[0078] Based on the above measuring device, the present application also provides a measuring method for detecting the cam lift of a camshaft, and the specific steps are as follows:

[0079] S100: Align the center line of the measuring device;

[0080] S200: equidistant calibration of the center line YY direction of the measuring device;

[0081] S300: Detecting the circular runout error of the base circle of the cam of the camshaft 200;

[0082] S400: measuring the cam lift of the exhaust cam by using an angle-determined lift method;

[0083] S500: measuring the cam lift of the intake cam by using a lift determination angle method;

[0084] S600: Measuring the cam lift of the fuel cam by using the lift determination angle method.

[0085] In this embodiment, the company's product 230 diesel engine camshaft is used as the detection object, and the specific structure of the corresponding camshaft 200 is as follows: Figure 2As shown, it includes a large end shaft diameter 201, an exhaust cam 202, an intake cam 203, a fuel cam 204, and a small end shaft diameter 205. The ends of the large end shaft diameter 201 and the small end shaft diameter 205 are respectively provided with a large end top hole 211 and a small end top hole 251.

[0086] Specifically, in step S100, the specific method for aligning the center line of the measuring device is as follows:

[0087] Install the zero-position calibration spindle 600 on the large center 3 and the small center 8, turn the small center moving handle 99 to complete the installation and fixation, install the height vernier caliper with the lever micrometer and place it on one side of the zero-position calibration spindle 600, measure the upper generatrix of the zero-position calibration spindle 600, and take data at the left, middle and right positions in the XX direction to ensure that the parallelism error between the zero-position calibration spindle 600 and the placement platform is less than 0.01mm.

[0088] Preferably, the circular run-out error of the zero-position calibration spindle 600 is less than 0.005 mm, and the optical indexing angle meter 100 is provided with an adjustment bolt for adjusting the height of the large center 3 to adjust the height of the zero-position calibration spindle 600 .

[0089] Specifically, in step S200, the specific method for calibrating the center line YY direction of the measuring device is as follows:

[0090] Loosen the set screw 5 of the cam lift reading device 400, make the measuring head 4 on the lift moving shaft 7 contact the front measuring generatrix of the zero position calibration spindle 600, take readings at the left, middle and right positions of the center line of the zero position calibration spindle 600 in the Y-Y direction, and observe that the maximum and minimum values ​​of the readings on the lift display screen 6 should be less than 0.01mm.

[0091] Preferably, the equidistant adjustment method is to adjust the position of the tailstock 300 on the placement platform.

[0092] The key point of measuring the exhaust cam lift, intake cam lift and fuel cam lift is to find the angle of the apex (the center line of the intake and exhaust cams and the maximum value of the fuel cam lift) on the angle display screen 1 at the top of the optical dividing angle meter 100, so as to accurately calculate the starting point angle of the cam lift and the ending point angle of the cam lift, and further measure and accurately calculate whether the lift value of each degree meets the technical requirements of the drawing.

[0093] Specifically, in step S300, the specific method for detecting the circular runout error of the base circle of the cam of the camshaft 200 is as follows:

[0094] Loosen the set screw 5 of the cam lift reading device 400, make the measuring head 4 contact the exhaust cam base circle, intake cam base circle and fuel cam base circle of the camshaft 200 respectively, rotate the camshaft 200, and confirm that the maximum and minimum readings of the lift display screen 6 are less than 0.01mm.

[0095] Specifically, the exhaust cam (see Figure 1 and Figure 7 ) The right lift and left lift of the lift are asymmetric cam lifts, where the right lift is 0° to 90°, 90° is the position of the peach tip (i.e. the center of the exhaust cam), and the left lift is 90° to 180°. For the measurement of the exhaust cam lift, we use the following measurement method: Angle determination lift method ( Figure 7 As shown in FIG. 1 ), the specific method for measuring the cam lift of the exhaust cam using the angle determination lift method is as follows:

[0096] S401: Loosen the set screw 5 of the cam lift reading device 400 to make the measuring head 4 contact the exhaust cam base circle point of the camshaft 200. At this time, the lift display screen 6 of the cam lift reading device 400 displays the cam base circle lift reading at this point, which is set to e1;

[0097] S402: query and obtain the theoretical lift value of angle a1 as l 1, rotate the camshaft 200 in the clockwise direction, and when the lift reading on the lift display screen 6 is e1+l 1, record the lift angle of the angle display screen 1 at this point and set it as m1;

[0098] S403: Continue to rotate the camshaft 200a2 in the clockwise direction to the middle position of the cam left lift. At this time, the lift reading of the lift display screen 6 is e2. At the same time, the lift angle of the angle display screen 1 is recorded and set to m2, where 2*a1+a2=180°;

[0099] S404: Find out that the theoretical lift value of the left lift a1+a2 is l2, then the theoretical lift difference between the right lift a1 and the left lift a1+a2 should be: l 1-l2;

[0100] S405: Calculate the actual lift difference as: e1+l 1-e2. When e1+l 1-e2=l 1-l2, execute step S406. Otherwise, jump to step S401 until e1+l 1-e2=l 1-l2. Record the lift angles m1 and m2 of two points on the angle display screen 1 at this time. Use m1+90-a1 or m2-(a1+a2-90) to get the lobe angle f of the exhaust cam.

[0101] S406: f-90° is the starting point n of the exhaust cam, f+90° is the ending point n of the exhaust cam, the camshaft is continuously rotated 200° clockwise to the ending point, the reading e3 of the lift display screen 6 is recorded, the camshaft is continuously rotated 200° clockwise to the starting point, the reading e4 of the lift display screen 6 is recorded, and (e3+e4) / 2=e5 is calculated;

[0102] S407: e4-e5 is the actual lift value at the beginning of exhaust cam n. Continue to rotate the camshaft 2001° clockwise, record the reading e6 on the lift display screen 6, e6-e5 is the actual lift value of the exhaust cam 1°, and so on, until the actual lift value is measured after the rotation completes 180°.

[0103] For example, the exhaust cam lift may be detected using angle combinations such as a1=40°, a1+a2=140°, a1=35°, a1+a2=145°, or a1=45°, a1+a2=135°.

[0104] Specifically, the intake cam (see Figure 1 and Figure 8 ) The right and left lifts of the lift are symmetrical cam lifts, where the right lift is 0° to 85.5°, 85.5° is the position of the apex (i.e. the center of the intake cam), and the left lift is 85.5° to 0°. For the measurement of the intake cam lift, we use the following measurement method: lift determination angle method ( Figure 8 As shown in FIG. 1 ), the specific method for measuring the cam lift of the intake cam using the lift determination angle method is as follows:

[0105] S501: Loosen the set screw 5 of the cam lift reading device 400 to make the measuring head 4 contact the intake cam base circle point of the camshaft 200. At this time, the lift display screen 6 of the cam lift reading device 400 displays the cam base circle lift reading at this point, which is set to e1;

[0106] S502: Select a theoretical lift value of a certain angle b1 at the middle position of the right lift of the intake cam, set it as L, rotate the camshaft 200 in the clockwise direction to the middle position of the right lift of the cam, and when the lift value of the lift display screen 6 is e1+L, record the lift angle of the angle display screen 1 as m1;

[0107] S503: Rotate the camshaft 200 in a clockwise direction, and when the measuring head 4 reaches the left lift position of the intake cam, find the lift point where the lift value of the lift display screen 6 is e1+L, and record the lift angle of the angle display screen 1 as m2;

[0108] S504: Calculate m1+m2 / 2=f, where f is the intake cam lobe position angle;

[0109] S505: f-85.5° is the starting point n of the intake cam, f°+90° is the ending point n of the intake cam, the camshaft is continuously rotated 200° clockwise to the starting point n, the reading e3 of the lift display screen 6 is recorded, the camshaft is continuously rotated 200° clockwise to the ending point n, the reading e4 of the lift display screen 6 is recorded, and (e3+e4) / 2=e5 is calculated;

[0110] S506: e4-e5 is the actual lift value at the beginning of the intake cam n. Continue to rotate the camshaft 2001° clockwise, record the reading e6 on the lift display screen 6, e6-e5 is the actual lift value of the intake cam 1°, and so on, until the actual lift value of 171° is measured.

[0111] Specifically, the fuel cam (see Figure 1 and Fig. 9 ) The lift is a single-sided lift cam, from 0° to 50.3° is the right single-sided lift, 50.3° is the peach tip (i.e. the maximum lift of the gas cam), and the left single-sided lift is 50.3° to 251.8°. For the measurement of the fuel cam lift, we use the measurement method: lift determination angle method. The specific method of measuring the cam lift of the fuel cam using the lift determination angle method is:

[0112] S601: Loosen the set screw 5 of the cam lift reading device 400 to make the measuring head 4 contact with the gas cam base circle point of the camshaft 200. At this time, the lift display screen 6 of the cam lift reading device 400 displays the cam base circle lift reading at this point, which is set to e1.

[0113] S602: Take a theoretical lift value of an angle α on the right single-sided lift of the gas cam, set it as L, and then rotate the camshaft 200 in the clockwise direction. When the lift value on the lift display screen 6 is e1+L, the lift angle on the angle display screen 1 is recorded as m1;

[0114] S603: Calculate the angle of the fuel cam lobe on the angle display screen 1 as: f=m1+(50.3°-α), then f-50.3 is the starting point n of the gas cam, rotate the camshaft 200 degrees clockwise to the starting point n of the gas cam, and at this time record the lift reading on the lift display screen 6 as e2;

[0115] S604: The actual lift value of the gas cam n at the beginning is equal to 0. Continue to rotate the camshaft clockwise by 2001° and record the reading e3 on the lift display screen 6. Then e3-e2 is the actual lift value of the gas cam 1°, and so on, until the actual lift value of 251.8° is measured after the rotation is completed.

[0116] It should be noted that in order to accurately determine the angular position of the lobe tip and the starting point angle n of the gas cam, two more lift values ​​of any angle α in the middle position of the right single-sided lift of the gas cam from approximately 0° to 50.3° can be taken, and measurements can be performed according to the above steps 601 to S604, and an evaluation and analysis of the uncertainty of the measurement results can be performed to finally determine the most correct lobe tip position.

[0117] The exhaust cam lift is measured by the angle-determined lift method, the intake cam lift is measured by the lift-determined angle method, and the fuel cam lift is measured by the lift-determined angle method. The above measurement methods are unique, novel, clever, distinctive and rich. In this embodiment, the detection method of the camshaft lift of the company's product 230 diesel engine is taken as an example, and then extended to this camshaft lift detection method, which can be applied to the measurement of camshaft lift of all other series and models of diesel engines.

[0118] The above measurement method is measured on a high-precision cam lift measuring instrument and uses precise calculations. The accuracy can be guaranteed, but there will still be certain measurement errors in the measurement process, which can be analyzed from the following aspects:

[0119] 1. The accuracy of the lever micrometer is 0.002mm, and the error generated during the measurement process is: Δ1 = 0.002mm.

[0120] 2. The circular runout error of the camshaft base circle is less than 0.02mm, and the measurement error generated during the detection is approximately: Δ2≈0.02mm.

[0121] 3. The error caused by the equal height and equal distance of the center line of the cam lift measuring device is approximately: Δ3≈0.01mm.

[0122] 4. The lift accuracy error of the camshaft lift measuring device is: Δ4 = 0.001 mm

[0123] 5. The placement platform also has flatness errors and other errors caused by other reasons, which can be ignored.

[0124] 6. Random error Δ varies with the temperature, lubrication conditions, reading errors, etc. during measurement. Random error can be reduced by improving the measurement conditions and taking the average of multiple measurements as the result. The confidence probability of random error calculated by the following formula is 95%.

[0125]

[0126] Where:

[0127] x i : The reading error of the i-th measurement.

[0128] x: The average of the reading errors of the nth measurement.

[0129] n: number of measurements

[0130] Knowing the above errors, the total measurement error is:

[0131]

[0132] The accuracy of the measurement is determined by the systematic error and the random error, which indicates the correctness of the measurement result. Although there is a certain measurement error in the measurement process, it is acceptable as long as it is controlled within a reasonable and effective range.

[0133] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0134] Although the above describes the specific implementation methods of the present application in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present application. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present application, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present application.

Claims

1. A measuring device for detecting cam lift of a camshaft, characterized in that: include: An optical indexing angle meter (100), a tailstock (300), a cam lift reading device (400), and a zero position calibration spindle (600); The optical indexing angle meter (100) and the tailstock (300) are used to clamp the camshaft (200); the optical indexing angle meter (100) is also used to measure the rotation angle of the camshaft (200); and the tailstock (300) can move linearly along the XX direction; The cam lift reading device (400) is used to complete the reading measurement of the cam lift in the YY direction; The zero position calibration spindle (600) is used to complete the calibration of the cam lift reading device (400) with equal height of the center line and equal distance in the YY direction.

2. A measuring device for detecting cam lift of a camshaft according to claim 1, characterized in that: The optical indexing angle meter (100) is provided with a large top (3) on one side in the X direction, an angle display screen (1) is provided on the top, and a rotating handle (2) is provided on one side in the Y direction; The tailstock (300) is provided with a small centering point (8) on one side in the X direction, and a small centering point moving handle (9) is provided on the symmetrical side thereof; A lift moving shaft (7) is arranged on one side of the cam lift reading device (400) in the Y direction, a measuring head (4) is arranged at the front end of the lift moving shaft (7), a set screw (5) is arranged on one side of the cam lift reading device (400) in the X direction, and a lift display screen (6) is arranged on the top of the lift moving shaft (7).

3. A measuring device for detecting cam lift of a camshaft according to claim 2, characterized in that: It also includes a special clamp (500), which includes two flanges (501) arranged in parallel and connected, and a first clamping bolt (502) and a clamping mechanism are arranged on the outer periphery of the flange (501), the first clamping bolt (502) spirally penetrates the side wall of the flange (501), and the clamping mechanism includes a flange joint (504) and a second clamping bolt (503), the flange joint (504) includes two convex plates arranged in parallel on the outer periphery of the flange (501), and the second clamping bolt (503) penetrates one of the convex plates and is spirally connected to the other one.

4. A measuring device for detecting cam lift of a camshaft according to claim 2, characterized in that: The measuring head (4) is marked with a marking center line (41).

5. A method for measuring the cam lift of a camshaft, characterized in that: Based on the measuring device according to any one of claims 1 to 4, the specific steps are as follows: S100: Align the center line of the measuring device; S200: equidistant calibration of the center line YY direction of the measuring device; S300: performing circular runout error detection on a base circle of a cam of a camshaft (200); S400: measuring the cam lift of the exhaust cam by using an angle-determined lift method; S500: measuring the cam lift of the intake cam by using a lift determination angle method; S600: Measuring the cam lift of the fuel cam by using the lift determination angle method.

6. A method for measuring camshaft cam lift according to claim 5, characterized in that: In step S100, the specific method for aligning the center line of the measuring device is as follows: Install the zero-position calibration spindle (600) on the large center (3) and the small center (8), turn the small center moving handle (9) to complete the installation and fixation, install the height vernier caliper with the lever micrometer and place it on one side of the zero-position calibration spindle (600), measure the upper generatrix of the zero-position calibration spindle (600), and take data at the left, middle and right positions in the XX direction to ensure that the parallelism error between the zero-position calibration spindle and the placement platform is less than 0.01 mm; In step S200, the specific method for calibrating the center line YY direction of the measuring device is as follows: Loosen the set screw (5) of the cam lift reading device (400) to make the measuring head (4) on the lift moving shaft (7) contact the front measuring generatrix of the zero position calibration spindle (600), and take readings at the left, middle and right positions of the center line of the zero position calibration spindle (600) in the YY direction. Observe that the maximum and minimum values ​​of the readings on the lift display screen (6) should be less than 0.01 mm.

7. The method for measuring the cam lift of a camshaft according to claim 5, characterized in that: In step S300, the specific method for detecting the circular runout error of the base circle of the cam of the camshaft (200) is as follows: Loosen the set screw (5) of the cam lift reading device (400), make the measuring head (4) contact the exhaust cam base circle, the intake cam base circle and the fuel cam base circle of the camshaft (200), rotate the camshaft (200), and confirm that the maximum and minimum readings of the lift display screen (6) are less than 0.01 mm.

8. The method for measuring the cam lift of a camshaft according to claim 5, characterized in that: In step S400, the specific method of measuring the cam lift of the exhaust cam using the angle determination lift method is as follows: S401: Loosen the set screw (5) of the cam lift reading device (400) to make the measuring head (4) contact the exhaust cam base circle point of the camshaft (200). At this time, the lift display screen (6) of the cam lift reading device (400) displays the cam base circle lift reading at this point, which is set to e1; S402: query and obtain the theoretical lift value of angle a1 as l 1, rotate the camshaft (200) in the clockwise direction, and when the lift reading on the lift display screen (6) is e1+l 1, record the lift angle of the angle display screen (1) at this point and set it as m1; S403: Continue to rotate the camshaft (200) in the clockwise direction by an angle of a2 to the middle position of the cam left lift. At this time, the lift reading on the lift display screen (6) is e2. At the same time, the lift angle on the angle display screen (1) is recorded and set to m2, where 2*a1+a2=180°; S404: Find out that the theoretical lift value of the left lift a1+a2 is l 2, then the theoretical lift difference between the right lift a1 and the left lift a1+a2 should be: l 1-l 2; S405: Calculate the actual lift difference as: e1+1 1-e2. When e1+1 1-e2=1 1-1 2, execute step S406. Otherwise, jump to step S401 until e1+1 1-e2=1 1-1 2. Record the lift angles m1 and m2 of the two points on the angle display screen (1). Use m1+(90-a1) or m2-(a2-90) to obtain the lobe angle f of the exhaust cam. S406: f-90° is the starting point n of the exhaust cam, f+90° is the ending point n of the exhaust cam, the camshaft (200) is continuously rotated clockwise to the ending point, the reading e3 of the lift display screen (6) is recorded, the camshaft (200) is continuously rotated clockwise to the starting point, the reading e4 of the lift display screen (6) is recorded, and (e3+e4) / 2=e5 is calculated; S407: (e4-e5) is the actual lift value of the exhaust cam n at the beginning. Continue to rotate the camshaft (200) 1° clockwise and record the reading e6 on the lift display screen (6). (e6-e5) is the actual lift value of the exhaust cam 1°, and so on until the actual lift value is measured after the rotation completes 180°.

9. The method for measuring the cam lift of a camshaft according to claim 5, characterized in that: In step S500, the specific method of measuring the cam lift of the intake cam using the lift determination angle method is: S501: Loosen the set screw (5) of the cam lift reading device (400) to make the measuring head (4) contact the intake cam base circle point of the camshaft (200). At this time, the lift display screen (6) of the cam lift reading device (400) displays the cam base circle lift reading at this point, which is set to e1; S502: Select a theoretical lift value of a certain angle b1 at the middle position of the right lift of the intake cam, set it as L, rotate the camshaft (200) in a clockwise direction to the middle position of the right lift of the cam, and when the lift value on the lift display screen (6) is e1+L, record the lift angle on the angle display screen (1) as m1; S503: Rotate the camshaft (200) in a clockwise direction, and when the measuring head (4) reaches the left lift position of the intake cam, find the lift point where the lift value on the lift display screen (6) is e1+L, and record the lift angle on the angle display screen (1) as m2; S504: Calculate (m1+m2) / 2=f, where f is the intake cam lobe position angle; S505: f-85.5° is the starting point n of the intake cam, f°+90° is the ending point n of the intake cam, the camshaft (200) is continuously rotated clockwise to the starting point n, the reading e3 of the lift display screen (6) is recorded, the camshaft (200) is continuously rotated clockwise to the ending point n, the reading e4 of the lift display screen (6) is recorded, and (e3+e4) / 2=e5 is calculated; S506: e4-e5 is the actual lift value at the beginning of the intake cam n. Continue to rotate the camshaft (200) 1° clockwise, record the reading e6 on the lift display screen (6), e6-e5 is the actual lift value of the intake cam 1°, and so on, until the actual lift value of 171° is measured.

10. The method for measuring the cam lift of a camshaft according to claim 5, characterized in that: In step S600, the specific method of measuring the cam lift of the fuel cam using the lift determination angle method is as follows: S601: Loosen the set screw (5) of the cam lift reading device (400) to make the measuring head (4) contact the gas cam base circle point of the camshaft (200). At this time, the lift display screen (6) of the cam lift reading device (400) displays the cam base circle lift reading at this point, which we set as e1; S602: Take any theoretical lift value of an angle α on the right single-sided lift of the gas cam, set it as L, and then rotate the camshaft (200) in the clockwise direction. When the lift value on the lift display screen (6) is e1+L, record the lift angle on the angle display screen (1) as m1; S603: Calculate the angle of the fuel cam lobe on the angle display screen (1): f = m1 + (50.3° - α), then f - 50.3 is the starting point n of the gas cam, rotate the camshaft (200) clockwise to the starting point n of the gas cam, and at this time record the lift reading on the lift display screen (6) as e2; S604: The actual lift value of the gas cam n at the beginning is equal to 0. The camshaft (200) continues to rotate clockwise by 1°, and the reading e3 on the lift display screen (6) is recorded. Then e3-e2 is the actual lift value of the gas cam 1°, and so on, until the actual lift value of 251.8° is measured after the rotation is completed.

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