Digital valve timing measuring instrument for engine

Abstract

The invention discloses an engine digital valve timing measuring instrument, which relates to the technical field of engines, and comprises a connecting gear, a valve timing measuring device, a valve timing measuring device and a valve timing measuring device, an input shaft of the gear ratio changing mechanism is connected with the connecting gear, and the gear ratio changing mechanism is used for increasing the ratio of the flywheel gear ring and outputting the flywheel gear ring; the counting unit is connected with the output shaft of the gear ratio changing mechanism and used for converting the rotation angle of the output shaft of the gear ratio changing mechanism into a rotation angle signal of a crankshaft of the engine. The number of teeth of the flywheel gear ring is converted according to a certain increase ratio through the gear ratio changing mechanism, if the flywheel gear ring rotates by one circle, the number of turns of the gear driving the output shaft to rotate in the gear ratio changing mechanism is large, the crank angle corresponding to one tooth on the gear is smaller, and the counting unit converts the rotating angle of the output shaft into the crank angle. Compared with the prior art in which the number of teeth of the flywheel gear ring is directly counted, the measurement precision of the crank angle is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of engines, in particular to an engine digital valve timing phase measuring instrument. Background Art

[0002] Large-bore engines have large cylinder diameters and long strokes, and their own friction torque is large. During engine installation and testing, it is necessary to adjust and check the engine's valve timing (valve timing: the crankshaft angle is used to indicate the opening and closing time and duration of the intake and exhaust valves). There are basically two methods for measuring the valve timing of large-bore engines:

[0003] (1) The calculation method of measuring the arc length of the flywheel rotation is to measure the circumference of the flywheel, calculate the arc length corresponding to each angle, and then calculate the crankshaft angle based on the arc length of the flywheel rotation.

[0004] (2) Calculation method based on the number of teeth rotated: Count the number of teeth on the flywheel gear ring and calculate the angle corresponding to each tooth. Then, calculate the crankshaft angle based on the number of teeth rotated by the flywheel gear ring. However, since there are fewer teeth on the flywheel gear ring and the angle corresponding to each tooth is large, the error is relatively large.

[0005] In addition, both methods require data calculation and the operation of multiple employees, which is complicated and has large errors. Summary of the invention

[0006] In view of the above-mentioned deficiencies, the technical problem to be solved by the present invention is to provide an engine digital valve timing measuring instrument with accurate measurement.

[0007] In order to solve the above technical problems, the technical solution of the present invention is:

[0008] An engine digital valve timing measuring instrument, comprising:

[0009] A connecting gear, the connecting gear being used to mesh with a flywheel ring gear of an engine;

[0010] A gear ratio changing mechanism, wherein the input shaft of the gear ratio changing mechanism is connected to the connecting gear, and the gear ratio changing mechanism is used to increase the output ratio of the flywheel ring gear;

[0011] A counting unit is connected to the output shaft of the gear ratio changing mechanism and is used to convert the rotation angle of the output shaft of the gear ratio changing mechanism into a rotation angle signal of the crankshaft of the engine.

[0012] Preferably, the gear ratio changing mechanism is a planetary gear mechanism, which comprises a ratio changing ring gear, a planetary gear and a sun gear, wherein the planetary gear is mounted on a planet carrier, and the planetary gear is meshed with the ratio changing ring gear and the sun gear;

[0013] The variable ratio gear ring is fixedly arranged, the planet carrier is coaxially connected with the connecting gear via an input shaft, and the sun gear is connected with the counting unit via an output shaft.

[0014] Preferably, the counting unit comprises a signal disk, a sensor and a counting module;

[0015] The sun gear is coaxially connected to the signal disk through the output shaft. The signal disk has a plurality of trigger structures evenly distributed around the circumference. The sensor corresponds to the position of the trigger structure. When the sensor senses the trigger structure, the counting module counts once.

[0016] Preferably, the trigger structure is a magnet, and the sensor is a Hall sensor.

[0017] Preferably, the Hall sensor is a bidirectional Hall sensor.

[0018] Preferably, the magnet is mounted on a magnet fixing seat, and the magnet fixing seat is fixed on the signal disk.

[0019] Preferably, the counting module comprises a counter electrically connected to the sensor, and the counter is electrically connected to an instrument switch, a reset switch, a battery access switch and a battery respectively.

[0020] Preferably, the battery is electrically connected to a voltmeter and a charging port.

[0021] Preferably, the trigger structure is a photoelectric encoder, and the sensor is a photoelectric sensor.

[0022] Preferably, the ratio gear ring and the sensor are fixed on a housing, and the input shaft and the output shaft are rotatably mounted on the housing.

[0023] After adopting the above technical solution, the beneficial effects of the present invention are:

[0024] The present application uses a gear ratio mechanism to convert the number of teeth of the flywheel gear ring according to a certain ratio. If the flywheel gear ring rotates one circle, the gear driving the output shaft in the gear ratio mechanism rotates more circles, and the crankshaft angle corresponding to one tooth on the gear is smaller. The counting unit converts the angle of the output shaft into the crankshaft angle. Compared with the prior art of directly counting the number of teeth of the flywheel gear ring, the measurement accuracy of the crankshaft angle is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an embodiment of the engine digital valve timing measuring instrument of the present invention;

[0026] Figure 2 yes Figure 1 A schematic cross-sectional view of the gear ratio mechanism;

[0027] Figure 3 yes Figure 2 Schematic diagram of the structure of the middle signal panel;

[0028] Figure 4 yes Figure 2 Schematic diagram of the exploded structure of the signal disk and magnet;

[0029] Figure 5 It is a schematic diagram of the principle of the counting unit;

[0030] In the figure: 1. connecting gear; 2. flywheel ring gear; 3. gear ratio mechanism; 31. input shaft; 32. ratio ring gear; 33. planetary gear; 34. planetary carrier; 35. sun gear; 36. output shaft; 37. housing; 4. counting unit; 41. signal disk; 411. through hole; 42. trigger structure; 421. magnet; 422. magnet fixing seat; 423. bolt; 43. sensor; 44. counter; 45. instrument switch; 46. reset switch; 47. battery access switch; 48. battery; 49. voltmeter; 40. charging port. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] like Figure 1 As shown, an engine digital valve timing measuring instrument comprises:

[0033] A connecting gear 1, the connecting gear 1 is used to mesh with a flywheel ring gear 2 of the engine;

[0034] A gear ratio changing mechanism 3, wherein an input shaft 31 of the gear ratio changing mechanism 3 is connected to the connecting gear 1, and the gear ratio changing mechanism 3 is used for increasing the output ratio of the flywheel ring gear 2;

[0035] The counting unit 4 is connected to the output shaft 36 of the gear ratio changing mechanism 3 and is used for converting the rotation angle of the output shaft 36 of the gear ratio changing mechanism 3 into a rotation angle signal of the crankshaft of the engine.

[0036] When measuring the rotation angle of the crankshaft, the connecting gear 1 is meshed with the flywheel gear ring 2. When the flywheel gear ring 2 rotates, it drives the connecting gear 1 to rotate. The connecting gear 1 drives the gear ratio mechanism 3. The number of teeth of the flywheel gear ring 2 is converted according to a certain ratio through the gear ratio mechanism 3. If the flywheel gear ring 2 rotates one circle, the gear in the gear ratio mechanism 3 that drives the output shaft 36 to rotate rotates more circles, and the crankshaft rotation angle corresponding to one tooth on the gear is smaller. The counting unit 4 converts the angle of rotation of the output shaft 36 into the crankshaft rotation angle. Compared with the prior art of directly counting the number of teeth of the flywheel gear ring 2, the measurement accuracy of the crankshaft rotation angle is greatly improved. According to the module of the flywheel gear ring 2 of different engines, the connecting gear 1 is replaced, and the versatility is good.

[0037] like Figure 2 As shown, the gear ratio mechanism 3 is a planetary gear mechanism, which includes a ratio ring gear 32, planetary gears 33 and a sun gear 35. The planetary gears 33 are mounted on a planet carrier 34, and the planetary gears 33 are meshed with the ratio ring gear 32 and the sun gear 35 respectively; the ratio ring gear 32 is fixedly arranged, the planetary carrier 34 is coaxially connected with the connecting gear 1 through the input shaft 31, and the sun gear 35 is connected with the counting unit 4 through the output shaft 36. When the connecting gear 1 rotates, the connecting gear 1 drives the planetary carrier 34 to rotate through the input shaft 31, and the planetary carrier 34 drives each planetary gear 33 to revolve around the sun gear 35, and at the same time, the planetary gears 33 rotate, the planetary gears 33 drive the sun gear 35 to rotate, and the sun gear 35 drives the output shaft 36 to rotate.

[0038] The counting unit 4 includes a signal disk 41, a sensor 43 and a counting module;

[0039] The sun gear 35 is coaxially fixedly connected to the signal disk 41 through the output shaft 36. The signal disk 41 has multiple trigger structures 42 evenly distributed around the circumference. The sensor 43 corresponds to the position of the trigger structure 42. When the output shaft 36 drives the signal disk 41 to rotate, the sensor 43 continuously senses the trigger structure 42. Each time it senses, the counting module counts once, thereby converting the number of teeth rotated by the flywheel ring gear 2 into a crankshaft angle signal.

[0040] like Figure 3 and Figure 4 As shown together, preferably, in the illustrated embodiment, the trigger structure 42 is a magnet 421, and the sensor 43 is a Hall sensor. Furthermore, the Hall sensor is a bidirectional Hall sensor, and the bidirectional Hall sensor can be triggered regardless of whether the signal disk 41 rotates clockwise or counterclockwise, and the counting is accurate. A through hole 411 is provided on the signal disk 41, and the magnet 421 is installed on the magnet fixing seat 422. The bolt 423 passing through the through hole 411 fixes the magnet fixing seat 422 to the signal disk 41. In other embodiments, the trigger structure 42 is preferably a photoelectric code disk, and the sensor is a photoelectric sensor.

[0041] like Figure 5As shown, the counting module includes a counter 44, which is electrically connected to the bidirectional Hall sensor, and the counter 44 is electrically connected to the instrument switch 45, the reset switch 46, the battery access switch 47 and the battery 48. When the instrument switch 45 and the battery access switch 47 are closed, the counter 44 works, and when the reset switch 46 is closed, the counter 44 is reset.

[0042] The battery 48 is also electrically connected to a voltmeter 49 and the charging port 40. The voltmeter 49 is used to monitor the voltage of the battery 48. When the voltage is too low, it means that the battery 48 is insufficient. At this time, an external power source is connected through the charging port 40 to charge the battery 48.

[0043] The ratio gear ring 2 and the sensor 43 are fixed on the housing 37, and the input shaft 31 and the output shaft 36 are rotatably mounted on the housing 37, integrating the gear ratio mechanism 3 and the counting unit 4 together, with high integration and easy installation.

[0044] The transmission ratio calculation of the engine digital valve timing measuring instrument of the present invention is:

[0045] The motion characteristic equation of the planetary gear mechanism:

[0046] n1+an2=(1+a)n3

[0047] n1 represents the rotation speed of the sun gear 35 , n2 represents the rotation speed of the variable ratio ring gear 32 , n3 represents the rotation speed of the planet carrier 34 , a=Z2 / Z1 , Z1 represents the number of teeth of the sun gear 35 , and Z2 represents the number of teeth of the variable ratio ring gear 32 .

[0048] The transmission ratio of the planetary gear mechanism is:

[0049] n3 / n1=Z1 / (Z1+Z2)

[0050] The transmission ratio between the connecting gear 1 and the signal disc 41 is:

[0051] n4 / n5=Z' / z*Z1 / (Z1+Z2)

[0052] n4 represents the rotation speed of the connecting gear 1 , n5 represents the rotation speed of the signal disk 41 , Z′ represents the number of teeth of the connecting gear 1 , and z represents the number of magnets 421 on the limit disk 41 .

[0053] The transmission signal ratio between the flywheel ring gear 2 and the signal disc 41 is:

[0054] n6 / n5=Z / (Z' / z*Z1 / (Z1+Z2))

[0055] n6 represents the rotation speed of the flywheel ring gear 2, and Z represents the number of teeth of the flywheel ring gear 2.

[0056] Example: Z2=46, Z1=14, Z'=15, z=9, Z=180; then n6 / n5=3240 / 7≈463.

[0057] For every rotation of the flywheel gear ring 2, the bidirectional Hall sensor senses that approximately 463 magnets 421 rotate. That is, the crankshaft angle corresponding to one rotation of the flywheel gear ring 2 is approximately divided into 463 parts, 360 / 463≈0.7°, and the angle corresponding to each magnet 421 is approximately 0.7°. If the method of directly counting the number of teeth rotated by the flywheel gear ring 2 in the prior art is adopted, the degree corresponding to one tooth on the flywheel gear ring 2 is 360 / 180=2°. Compared with the prior art, the measurement accuracy is approximately three times higher, and the measurement accuracy is greatly improved.

[0058] The above are examples of the best implementation of the present invention, and the parts not described in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical enlightenment of the present invention is also within the protection scope of the present invention.

Claims

1. An engine digital valve timing measuring instrument, characterized in that: include: A connecting gear, the connecting gear being used to mesh with a flywheel ring gear of an engine; A gear ratio changing mechanism, wherein the input shaft of the gear ratio changing mechanism is connected to the connecting gear, and the gear ratio changing mechanism is used to increase the output ratio of the flywheel ring gear; A counting unit is connected to the output shaft of the gear ratio changing mechanism and is used to convert the rotation angle of the output shaft of the gear ratio changing mechanism into a rotation angle signal of the crankshaft of the engine.

2. The engine digital valve timing measuring instrument according to claim 1, characterized in that: The gear ratio changing mechanism is a planetary gear mechanism, which includes a ratio changing ring gear, planetary gears and a sun gear, wherein the planetary gears are mounted on a planet carrier, and the planetary gears are meshed with the ratio changing ring gear and the sun gear; The variable ratio gear ring is fixedly arranged, the planet carrier is coaxially connected with the connecting gear via an input shaft, and the sun gear is connected with the counting unit via an output shaft.

3. The engine digital valve timing measuring instrument as claimed in claim 2, characterized in that: The counting unit includes a signal disk, a sensor and a counting module; The sun gear is coaxially connected to the signal disk through the output shaft. The signal disk has a plurality of trigger structures evenly distributed around the circumference. The sensor corresponds to the position of the trigger structure. When the sensor senses the trigger structure, the counting module counts once.

4. The engine digital valve timing measuring instrument as claimed in claim 3, characterized in that: The trigger structure is a magnet, and the sensor is a Hall sensor.

5. The engine digital valve timing measuring instrument as claimed in claim 4, characterized in that: The Hall sensor is a bidirectional Hall sensor.

6. The engine digital valve timing measuring instrument as claimed in claim 4, characterized in that: The magnet is mounted on a magnet fixing seat, and the magnet fixing seat is fixed on the signal disk.

7. The engine digital valve timing measuring instrument as claimed in claim 3, characterized in that: The counting module comprises a counter electrically connected to the sensor, and the counter is electrically connected to the instrument switch, the reset switch, the battery access switch and the battery respectively.

8. The engine digital valve timing measuring instrument as claimed in claim 7, characterized in that: The battery is electrically connected to a voltmeter and a charging port.

9. The engine digital valve timing measuring instrument as claimed in claim 3, characterized in that: The trigger structure is a photoelectric encoder, and the sensor is a photoelectric sensor.

10. The engine digital valve timing measuring instrument as claimed in claim 3, characterized in that: The ratio gear ring and the sensor are fixed on the housing, and the input shaft and the output shaft are rotatably mounted on the housing.

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