Method and apparatus for marking top dead center of a diesel engine

Abstract

The present application relates to diesel engine assembly technical field, especially a kind of diesel engine top dead center marking method and its equipment, overcome the existing top dead center marking precision is not high and artificial workload cumbersome problem, method has process: one, set up marking station on assembly line, drive flywheel drive device is arranged in the side of the work station flow plate, first optical sensor is arranged in the upper position of the work station and detects piston position, also set laser detection marking instrument, control device signal is connected drive device, first optical sensor and laser detection marking instrument;Two, drive flywheel rotation at least one week by drive device, piston runs to top dead center at least once, when first optical sensor detects the shortest distance with piston, the rotation angle of drive device, drive device continues to rotate and stops rotating when subsequent rotation reaches the rotation angle, piston remains in top dead center position;Three, control device starts laser detection marking instrument to capture "0" mark line on flywheel and marks top dead center line on engine body which is aligned with "0" mark line.

Description

Technical Field

[0001] This invention relates to the field of diesel engine assembly technology, and in particular to a method and equipment for marking the top dead center of a diesel engine. Background Technology

[0002] The position of the diesel engine piston when it reaches its highest point, i.e., the maximum distance between the piston and the crankshaft rotation center, is called the top dead center (TDC). The TDC position of the piston can be observed before the cylinder head is assembled onto the cylinder block. However, after the cylinder head is assembled, the TDC position of the piston needs to be known to adjust and check the valve timing and / or fuel injection timing. Therefore, the TDC position needs to be marked before the cylinder head is assembled.

[0003] The existing method for marking top dead center (TDC) involves manually rotating the flywheel to bring the piston to its highest point. Then, an alignment mark is made on both the cylinder block and the flywheel. After the cylinder head is assembled, aligning the mark on the flywheel with the mark on the cylinder block confirms that the piston is at TDC. The disadvantages of this method are: 1. Measurement and reading errors exist when using tools and dial indicators to determine the piston's highest point, and the flywheel's rotation is manually controlled, making it difficult to maintain a stable position. 2. Manual marking also suffers from inconsistent and uneven alignment. Both of these drawbacks result in low accuracy and cumbersome manual work for TDC marking. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and equipment for marking the top dead center of a diesel engine, overcoming the problems of low marking accuracy and cumbersome manual workload in existing top dead center marking methods.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for marking the top dead center of a diesel engine, comprising the following process,

[0006] (i) A top dead center marking station is set up on the diesel engine assembly line. The assembly line moves backward. The top dead center marking station is located behind the gear chamber cover assembly station. A drive device for driving the flywheel to rotate is set on the side of the transfer plate at the top dead center marking station. A first optical sensor that illuminates the top surface of the piston to detect the piston position is set above the flywheel. A laser detection marking instrument is also set up at the top dead center marking station. A control device is set up to connect the control device signal to the drive device, the first optical sensor and the laser detection marking instrument.

[0007] (ii) After the diesel engine assembly moves to the top dead center marking station, the drive device drives the flywheel to rotate at least one revolution, and the piston runs to the top dead center at least once. The control device records the rotation angle of the drive device when the first optical sensor detects the shortest distance from the piston. The control device controls the drive device to continue rotating and stops rotating when it rotates to that angle, so that the piston is kept at the top dead center position.

[0008] (III) The control device starts the laser detection marker to capture the "0" mark that has been pre-marked on the flywheel, and then starts the laser detection marker to mark the upper dead point line that is aligned with the "0" mark on the body.

[0009] Specifically, in order to improve work efficiency, the cylinder head gasket thickness can be automatically detected and determined simultaneously during the top dead center marking. In process (1), the control device is connected to the display and the second optical sensor. The second optical sensor, which illuminates the upper end face of the piston cylinder, is set above the transfer plate at the top dead center marking station. In process (2), the control device measures the height difference between the highest point of the piston and the upper end face of the piston cylinder based on the second optical sensor and the first optical sensor, and displays the difference on the display. The required thickness of the gasket between the cylinder head and the piston cylinder is determined by the difference.

[0010] Specifically, in order to facilitate the assembly line to be suitable for the assembly of diesel engines of different shaft heights, process (II) also includes a process of aligning the shaft of the diesel engine with the shaft of the drive device after the gear chamber cover assembly is assembled. In process (II), the flexible drive disc of the drive device moves forward and presses against the outer end face of the flywheel to drive the flywheel to rotate.

[0011] Specifically, in order to facilitate the control and acquisition of the flywheel's rotation angle state, the motor that enables the flexible drive disk to rotate in the drive device is a stepper motor.

[0012] A diesel engine top dead center marking device using the above marking method is installed on the diesel engine assembly line. The assembly line moves backward, and the device is located behind the gear chamber cover assembly station. It includes a drive device, a first optical sensor, a laser detection marking instrument, and a control device.

[0013] The drive device has a flexible drive disc whose axis is aligned with the axis of the diesel engine flywheel and can be flexibly pressed against the outer end face of the flywheel. The drive device realizes the rotation of the flexible drive disc and the reciprocating movement of the flexible drive disc along its axis.

[0014] The first optical sensor is located above the diesel engine piston and illuminates the top surface of the piston;

[0015] The laser detection and marking instrument has a detector for capturing the "0" mark on the flywheel and a laser generator for marking the upper dead center line aligned with the "0" mark on the body;

[0016] The control device is signal-connected to the drive device, the first optical sensor, and the laser detection and marking instrument.

[0017] Specifically, in order to improve work efficiency, the equipment has not only a device for marking the top dead center, but also an automatic detection and determination device for the cylinder head gasket thickness. Therefore, the control device is also connected to a display and a second optical sensor. The second optical sensor is located above the diesel engine piston cylinder and illuminates the upper end face of the piston cylinder.

[0018] Specifically, in order to meet the marking requirements of diesel engines with different shaft heights, the control device is also connected to a lifting device. The lifting device is located below the assembly line transfer plate and lifts the diesel engine until the flywheel shaft is aligned with the flexible drive disc shaft.

[0019] Specifically, in order to facilitate the control and acquisition of the flywheel's rotation angle state, the motor that enables the flexible drive disk to rotate in the drive device is a stepper motor.

[0020] The beneficial effects of the present invention are: the top dead center marking method and equipment of the present invention, by using optical ranging and laser marking, realizes both the automated marking of the top dead center line and the determination of the thickness of the cylinder head gasket, so that the top dead center marking accuracy is high, avoiding complex manual workload and the problem of operational errors, and greatly improving work efficiency. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the top dead center marking device of the present invention;

[0023] Figure 2 yes Figure 1 Enlarged view of point A in the image;

[0024] Figure 3 This is a state diagram of the flexible drive disk of the upper dead point marking device of the present invention retracting.

[0025] In the figure: 1. Flow plate, 2. Flywheel, 3. Drive device, 3-1. Flexible drive disk, 4. Piston, 5. First optical sensor, 6. Laser detection marker, 7. Control device, 8. Display, 9. Second optical sensor, 10. Upper end face of piston cylinder, 11. Lifting device, 12. Top dead center line. Detailed Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings, which are simplified schematic diagrams illustrating only the basic structure of the invention and therefore only show the components relevant to the invention.

[0027] A method for marking the top dead center of a diesel engine, combined with an appendix Figure 1 To make this method easier to understand, the process is as follows:

[0028] (I) A top dead center marking station is set up on the diesel engine assembly line. The assembly line moves backward. The top dead center marking station is located behind the gear chamber cover assembly station. A drive device 3 that drives the flywheel 2 to rotate is set on the side of the flow plate 1 at the top dead center marking station. A first optical sensor 5 that illuminates the top surface of the piston 4 to detect the position of the piston 4 is set above it. A laser detection marking instrument 6 is also set at the top dead center marking station. A control device 7 is set up. The control device 7 is connected to the drive device 3, the first optical sensor 5 and the laser detection marking instrument 6. The control device 7 is also connected to the display 8 and the second optical sensor 9. A second optical sensor 9 that illuminates the upper end surface 10 of the piston cylinder is set above the flow plate 1 at the top dead center marking station.

[0029] (II) After the diesel engine assembly is moved to the top dead center marking station, the process of aligning the axis of the diesel engine with the axis of the gear chamber cover assembly with the axis of the drive device 3 is carried out. The vertical alignment is completed by the lifting device 11, and the horizontal alignment is completed when the top dead center marking station is set. The flexible drive disk 3-1 of the drive device 3 moves forward and pushes against the outer end face of the flywheel 2 to drive the flywheel 2 to rotate. The drive device 3 drives the flywheel 2 to rotate at least one revolution, and the piston 4 runs to the top dead center at least once. The control device 7 records the rotation angle of the drive device 3 when the first optical sensor 5 detects the shortest distance from the piston 4. The control device 7 controls the drive device 3 to continue rotating and stops rotating when it rotates to the same angle, so that the piston 4 is kept at the top dead center position. During this process, the control device 7 also measures the height difference between the highest point of the piston 4 and the upper end face 10 of the piston cylinder according to the second optical sensor 9 and the first optical sensor 5, and displays the difference on the display 8. The required thickness of the gasket between the cylinder head and the piston cylinder is determined by the difference.

[0030] (III) The control device 7 activates the laser detection marking instrument 6 to capture the pre-engraved "0" mark on the flywheel 2, and then activates the laser detection marking instrument 6 to mark the top dead center line 12 on the fuselage, which is aligned with the "0" mark. The "0" mark and the top dead center line 12 are as follows: Figure 2 As shown.

[0031] The motor that enables the flexible drive disk 3-1 to rotate in the drive device 3 is a stepper motor.

[0032] The first optical sensor 5 and the second optical sensor 9 can be laser rangefinders. The sensors calculate the time from the emission of the laser to the receipt of the reflected light and then determine the distance. Both the emission and reception of the laser are pulsed.

[0033] The diesel engine top dead center marking equipment used in the above method is still referred to in [reference needed]. Figure 1 The equipment is installed on the diesel engine assembly line, which moves backward. The equipment is located behind the gear chamber cover assembly station and includes a drive device 3, a first optical sensor 5, a laser detection marker 6, and a control device 7.

[0034] The drive device 3 has a flexible drive disk 3-1 whose axis is aligned with the axis of the diesel engine flywheel 2 and can be flexibly pressed against the outer end face of the flywheel 2. The drive device 3 realizes the rotation of the flexible drive disk 3-1 and realizes the reciprocating movement of the flexible drive disk 3-1 along its axis.

[0035] The first optical sensor 5 is located above the diesel engine piston 4 and illuminates the top surface of the piston 4;

[0036] The laser detection and marking instrument 6 has a detector for capturing the "0" mark on the flywheel 2 and a laser generator for marking the upper dead center line 12 aligned with the "0" mark on the body;

[0037] The control device 7 is connected to the drive device 3, the first optical sensor 5 and the laser detection marker 6. The control device 7 is also connected to the display 8 and the second optical sensor 9. The second optical sensor 9 is located above the diesel engine piston cylinder and illuminates the upper end face 10 of the piston cylinder.

[0038] The control device 7 is also connected to a lifting device 11, which is located below the assembly line transfer plate 1. The lifting device 11 lifts the diesel engine until the axis of the flywheel 2 is aligned with the axis of the flexible drive disc 3-1.

[0039] The motor that drives the flexible drive disk 3-1 to rotate is a stepper motor.

[0040] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for marking the top dead center of a diesel engine, characterized in that: It has the following process, (i) A top dead center marking station is set up on the diesel engine assembly line. The assembly line moves backward. The top dead center marking station is located behind the gear chamber cover assembly station. A drive device for driving the flywheel to rotate is set on the side of the transfer plate at the top dead center marking station. A first optical sensor that illuminates the top surface of the piston to detect the piston position is set above the flywheel. A laser detection marking instrument is also set up at the top dead center marking station. A control device is set up to connect the control device signal to the drive device, the first optical sensor and the laser detection marking instrument. (ii) After the diesel engine assembly moves to the top dead center marking station, the drive device drives the flywheel to rotate at least one revolution, and the piston runs to the top dead center at least once. The control device records the rotation angle of the drive device when the first optical sensor detects the shortest distance from the piston. The control device controls the drive device to continue rotating and stops rotating when it rotates to that angle, so that the piston is kept at the top dead center position. (iii) The control device starts the laser detection marker to capture the "0" mark that has been pre-marked on the flywheel, and then starts the laser detection marker to mark the top dead center line that is aligned with the "0" mark on the diesel engine body.

2. The method for marking the top dead center of a diesel engine according to claim 1, characterized in that: In process (I), the control device is connected to the display and the second optical sensor. The second optical sensor is installed above the flow plate at the top dead center marking station, illuminating the upper end face of the piston cylinder. In process (II), the control device measures the height difference between the highest point of the piston and the upper end face of the piston cylinder based on the second optical sensor and the first optical sensor, and displays the difference on the display. The required thickness of the gasket between the cylinder head and the piston cylinder is determined by the difference.

3. The method for marking the top dead center of a diesel engine according to claim 1, characterized in that: Process (ii) also includes the process of aligning the axis of the diesel engine with the axis of the drive unit after the gear chamber cover assembly is assembled.

4. The method for marking the top dead center of a diesel engine according to claim 1, characterized in that: In process (ii), the flexible drive disc of the drive device moves forward and presses against the outer end face of the flywheel to drive the flywheel to rotate.

5. The method for marking the top dead center of a diesel engine according to any one of claims 1 to 4, characterized in that: The motor that enables the flexible drive disk to rotate in the drive device is a stepper motor.

6. A diesel engine top dead center marking device applying the diesel engine top dead center marking method of claim 1, characterized in that: The equipment is installed on the diesel engine assembly line, which moves backward. The equipment is located behind the gear chamber cover assembly station and includes a drive device, a first optical sensor, a laser detection marker, and a control device. The drive device has a flexible drive disc whose axis is aligned with the axis of the diesel engine flywheel and can be flexibly pressed against the outer end face of the flywheel. The drive device realizes the rotation of the flexible drive disc and the reciprocating movement of the flexible drive disc along its axis. The first optical sensor is located above the diesel engine piston and illuminates the top surface of the piston; The laser detection marking instrument has a detector for capturing the "0" mark on the flywheel and a laser generator for marking the top dead center line aligned with the "0" mark on the diesel engine block; The control device is signal-connected to the drive device, the first optical sensor, and the laser detection and marking instrument.

7. The diesel engine top dead center marking device according to claim 6, characterized in that: The control device is also signal-connected to a display and a second optical sensor, which is located above the diesel engine piston cylinder and illuminates the upper end face of the piston cylinder.

8. The diesel engine top dead center marking device according to claim 6, characterized in that: The control device is also signal-connected to a lifting device, which is located below the assembly line transfer plate. The lifting device lifts the diesel engine until the flywheel axis is aligned with the flexible drive disc axis.

9. The diesel engine top dead center marking device according to claim 6, characterized in that: The motor that enables the flexible drive disk to rotate in the drive device is a stepper motor.

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