A piston timing gauge

Abstract

This invention discloses a piston timing adjustment instrument, including a measuring body and a sleeve. A probe is connected to the bottom of the instrument and passes through the sleeve. The probe can slide axially along the sleeve to detect piston stroke and transmit signals to the instrument. A fastening hole is formed on the outer periphery of the sleeve near the instrument, and a fastener, specifically a screw, is installed in the fastening hole. The screw engages with the threaded connection of the fastening hole to coaxially fix the sleeve and the probe. This invention, by providing an external thread at the end of the sleeve, allows for direct screwing into a pre-drilled threaded hole in the cylinder head to fix the instrument, eliminating the need for traditional bracket installation and disassembly steps, reducing tooling and accessories, lowering usage costs, and improving installation efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of engine testing tools, specifically relating to a piston timing adjustment instrument. Background Technology

[0002] Precise adjustment of engine piston timing is crucial for ensuring engine combustion efficiency, reducing emissions, and improving power performance. Currently, piston timing measuring tools often employ a "dial gauge + external bracket" structure. During use, the gauge must be clamped and fixed to the engine block or cylinder head using the bracket, and the bracket height and gauge position must be repeatedly adjusted to bring the probe into contact with the piston, thereby measuring the piston stroke and ignition advance / retard angle.

[0003] However, this traditional structure has obvious drawbacks: First, it requires an additional special bracket, which increases the cost of carrying and using tools, and the bracket installation takes a long time; second, the bracket height adjustment depends on manual experience, and repeated disassembly and adjustment are required to ensure that the probe and piston accurately contact each other, which is cumbersome and has low measurement efficiency. At the same time, it is easy to cause measurement errors due to improper adjustment, which affects the timing adjustment accuracy; third, the bracket fixing method has poor stability and is prone to loosening during engine testing, which further affects the reliability of the measurement results. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a piston timing adjustment instrument that achieves the technical effect of direct screw-on fixing without the need for an additional bracket and quick and accurate adjustment of the measurement depth, thereby improving the convenience and accuracy of piston timing measurement.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A piston timing adjustment instrument includes a measuring body and a sleeve. The measuring body includes an instrument and a probe. The probe is connected to the lower part of the instrument and passes through the sleeve. The probe can slide along the axial direction of the sleeve to detect the piston stroke and transmit the signal to the instrument.

[0006] A fastening hole is provided on the outer periphery of the end of the sleeve near the instrument. A fastener, specifically a screw, is installed in the fastening hole. The screw engages with the thread of the fastening hole to fix the sleeve and the probe coaxially. At the same time, it ensures that the relative position of the probe and the sleeve can be finely adjusted to meet the measurement requirements of different piston positions.

[0007] The end of the sleeve furthest from the instrument has an external thread that matches the pre-drilled mounting thread hole on the engine cylinder head, allowing the sleeve to be directly screwed into the cylinder head mounting position. This eliminates the need for an additional bracket, thus simplifying the installation process.

[0008] The sleeve is provided with a hexagonal square head and / or a square hole on the outer peripheral wall above the external thread. The hexagonal square head is integrally formed with the sleeve, and the square hole is a square through hole that penetrates the radial direction of the sleeve. The two can be set separately or simultaneously to adapt to the force of a wrench or special tool, realize the rotation adjustment of the sleeve, and thus accurately control the depth of the probe into the cylinder, and quickly complete the piston stroke measurement and timing angle adjustment.

[0009] Furthermore, the outer peripheral wall of the sleeve is provided with knurling. The knurling is located between the fastening hole and the external thread, and covers the fastening hole and the installation area of ​​the fastener. The knurling can increase the friction when the hand is holding it, making it easier to manually fine adjust the position of the sleeve, while also improving the structural strength of the sleeve.

[0010] Compared with the prior art, the present invention has the following beneficial effects: (1) No additional bracket required, easy installation: By setting an external thread at the end of the sleeve, the instrument can be fixed by directly screwing it into the reserved threaded hole in the cylinder head, eliminating the installation and disassembly steps of the traditional bracket, reducing tool accessories, lowering usage costs, and improving installation efficiency.

[0011] (2) Precise adjustment and efficient operation: The probe insertion depth is adjusted by rotating the threaded structure of the sleeve rod. With the force-generating structure of the hexagonal square head / square hole, the measurement position can be precisely controlled. There is no need for repeated disassembly and adjustment. The depth adjustment and measurement can be completed in one operation, which greatly improves the timing measurement efficiency and effectively reduces human adjustment error, ensuring measurement accuracy.

[0012] (3) Stable structure and strong practicality: Compared with the traditional bracket clamping, the threaded screw fixing method has higher fixing stability, avoids loosening during the testing process, and ensures the reliability of the measurement results. Attached Figure Description

[0013] Figure 1 To illustrate the three-dimensional structure of the present invention (view 1); Figure 2 This is a schematic diagram illustrating the exploded structure of a specific embodiment of the present invention; Figure 3 To illustrate the three-dimensional structure of the present invention (viewpoint two); Figure 4 This is a schematic diagram illustrating the three-dimensional structure of the sleeve in a specific embodiment of the present invention; The reference numerals in the accompanying drawings include: 1. Instrument; 2. Probe; 3. Sleeve; 5. Fastener; 6. External thread; 7. Hexagonal square head; 8. Square hole; 9. Knurling. Detailed Implementation

[0014] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0015] In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances. Example

[0016] like Figure 1 - Figure 4 As shown, a piston timing measurement instrument is mainly used for piston timing detection and adjustment in small gasoline engines (such as automobile and motorcycle engines). It includes a measuring body and a sleeve 3. The measuring body consists of an instrument 1 and a probe 2. The instrument 1 is a dial indicator with an accuracy of 0.01 mm and a range of 0-10 mm. It can accurately reflect the small displacement of the piston and meet the high precision requirements of timing adjustment. The probe 2 is made of hard alloy, which has high strength and high wear resistance, avoiding wear caused by long-term contact with the piston and affecting measurement accuracy. The probe 2 is vertically welded to the lower part of the measuring end of the instrument 1, and the probe 2 is set through the sleeve rod 3. The sleeve rod 3 has a through hole that matches the probe 2, ensuring that the probe 2 can slide smoothly along the axial direction of the sleeve rod 3 without jamming. The bottom end of the probe 2 is ground to form a smooth arc surface to avoid scratching the piston surface, while ensuring good contact with the top surface of the piston and accurately transmitting the piston displacement signal to the instrument 1.

[0017] The sleeve rod 3 is made of 45# steel, combining strength and lightweight, making it easy to carry and operate. Two symmetrical fastening holes are opened on the outer periphery of the end of the sleeve rod 3 near the instrument 1. The two fastening holes are symmetrically distributed radially along the sleeve rod 3, with an included angle of 180°. The fastening holes are M5 threaded holes, and fasteners 5 are installed in the fastening holes. Fasteners 5 are hexagon socket head cap screws made of stainless steel to prevent rust from affecting the fastening effect. By tightening the screw, the end of the screw is pressed against the outer peripheral wall of the probe 2, realizing the coaxial fixed connection between the sleeve rod 3 and the probe 2. At the same time, the relative position of the probe 2 and the sleeve rod 3 can be flexibly adjusted by finely adjusting the screw's screw insertion depth to adapt to the installation height of different engine piston models, expanding the tool's applicability range.

[0018] The end of the sleeve 3 furthest from the instrument 1 has an external thread 6. The external thread 6 is a fine thread, which is compatible with the pre-drilled threaded hole of the cylinder head of a common small gasoline engine. The sleeve 3 is directly screwed into the threaded hole of the cylinder head through the external thread 6. No additional tools are needed during the screwing process. The initial fixation can be completed manually. Then, the sleeve 3 is further tightened with tools to ensure that it is firmly fixed. No additional bracket is needed, which greatly simplifies the installation process and reduces the installation time by more than 60% compared with traditional bracket-type tools.

[0019] The sleeve rod 3 has an integrally formed hexagonal square head 7 on its outer peripheral wall above the external thread 6. It is compatible with standard open-end wrenches and box wrenches. When in use, the wrench is clamped on the hexagonal square head 7, and the sleeve rod 3 is rotated clockwise or counterclockwise to precisely adjust the depth of the probe 2 into the cylinder. The adjustment accuracy can reach 0.01mm. There is no need for repeated disassembly and adjustment. A single adjustment can make the probe 2 accurately contact the piston, which greatly improves the measurement efficiency. The hexagonal square head 7 and the sleeve 3 are integrally formed without welding marks, resulting in high structural strength and avoiding problems such as breakage and loosening during long-term use, thus extending the tool's service life.

[0020] The outer peripheral wall of the sleeve rod 3 is provided with knurling 9. The knurling 9 is located between the fastening hole and the external thread 6, with a length of 30mm and a width covering the fastening hole and the installation area of ​​the fastener 5. The knurling 9 is straight knurling with a groove depth of 0.5mm and a spacing of 1mm. It can increase the friction when the hand is gripping, making it easy for the operator to manually fine adjust the position of the sleeve rod 3. It can also improve the strength of the outer peripheral wall of the sleeve rod 3, avoid surface scratches, and at the same time play a certain anti-slip role to prevent the hand from slipping during operation.

[0021] The usage steps of this embodiment are as follows: 1. Preparation: Clean the reserved threaded holes on the engine cylinder head, remove dust, oil and debris from the holes, and ensure that the threads are clean to avoid affecting the screwing effect of the sleeve 3; check whether the instrument 1 is working properly, push the probe 2 to confirm that the probe 2 slides smoothly and the reading of the instrument 1 is accurate; check whether the fasteners 5 are tightened to avoid loosening during use.

[0022] 2. Installation and fixing: Hold the knurled area 9 of the sleeve rod 3, align the end of the sleeve rod 3 with the external thread 6 with the reserved threaded hole in the cylinder head, and manually screw it in clockwise until the sleeve rod 3 is initially fixed. Then use a No. 14 wrench to hold the hexagonal square head 7 and further tighten the sleeve rod 3 to ensure that the sleeve rod 3 is firmly fixed and there is no shaking.

[0023] 3. Depth adjustment: Hold the hexagonal square head 7 with a wrench, slowly rotate the sleeve 3, finely adjust the insertion depth of the probe 2, and observe the reading of the instrument 1 at the same time, until the bottom of the probe 2 gently touches the top surface of the engine piston and the reading of the instrument 1 is stable within 0.02mm, the depth adjustment is completed.

[0024] 4. Measurement and Adjustment: Rotate the engine crankshaft to make the piston reciprocate. Read the maximum and minimum stroke of the piston through instrument 1. Combined with the engine speed, calculate the ignition advance angle or retard angle. Based on the measurement results, adjust the engine timing mechanism until the standard timing requirements are met.

[0025] 5. Disassembly and Storage: After measurement and adjustment, use a wrench to rotate the hexagonal square head 7 in the opposite direction to unscrew the sleeve 3 from the threaded hole in the cylinder head, loosen the fastener 5, take out the probe 2, clean the dust and oil stains on the surface of the probe 2 and sleeve 3, and organize and store the instrument 1, probe 2, sleeve 3 and fastener 5 for future use. Example

[0026] The difference between this embodiment and embodiment 1 is that: a square hole 8 is opened on the outer peripheral wall of the sleeve rod 3 above the external thread 6, while retaining the hexagonal square head 7, which can be adapted to more operating scenarios. It is mainly used for piston timing detection and adjustment of large diesel engines (such as truck and construction machinery engines). The cylinder head thread hole of this type of engine is relatively deep, which requires higher rotational force of the sleeve rod 3. The dual force structure can improve the ease of operation.

[0027] Specifically, the square hole 8 is a square through hole that penetrates the sleeve 3 radially. The square hole 8 has a side length of 10mm and a depth of 20mm, and is suitable for inserting a special square wrench to apply force. The inner wall of the square hole 8 is polished, and the surface is smooth, which makes it easy to insert and pull out the wrench, while avoiding scratching the surface of the wrench.

[0028] In this embodiment, the sleeve 3 has a length of 150mm, an outer diameter of 25mm, and a wall thickness of 4mm, which is suitable for the installation depth requirements of large diesel engines; the external thread 6 adopts a fine thread of M25×1.5, with a pitch of 1.5mm and a length of 30mm, which is compatible with the reserved threaded hole of the cylinder head of large diesel engines. Instrument 1 uses a dial indicator with an accuracy of 0.001mm and a measuring range of 0-25mm, which meets the high-precision measurement requirements of piston stroke in large engines.

[0029] In this embodiment, the knurling 9 is a mesh knurling with a texture depth of 0.6mm, a spacing of 1.2mm, and a length of 40mm. It covers part of the fastening hole, fastener 5, and square hole 8, which is convenient for hand gripping and can also provide some protection for the square hole 8.

[0030] In addition, in this embodiment, the external thread 6 of the sleeve rod 3 is coated with an anti-rust coating, which can effectively prevent oil and water vapor generated during engine operation from corroding the thread and extend the service life of the thread; a sealing gasket is provided at the connection between the instrument 1 and the probe 2, which can prevent dust and oil from entering the interior of the instrument 1, protect the measuring element of the instrument 1, and improve the stability and service life of the instrument 1.

[0031] The remaining structure of this embodiment is the same as that of Embodiment 1, and will not be described again here.

[0032] Working principle The core working principle of this invention is to directly screw and fix the instrument 1 through the external thread 6 at the end of the sleeve rod 3, replacing the traditional bracket-type fixing method and simplifying the installation process; by using the thread transmission of the sleeve rod 3, rotating the sleeve rod 3 can precisely adjust the insertion depth of the probe 2, and the force-generating structure with the hexagonal square head 7 and square hole 8 improves the convenience and accuracy of adjustment; after the probe 2 abuts against the piston, it transmits the reciprocating movement signal of the piston to the instrument 1, and obtains the piston stroke data through the reading of the instrument 1, thereby determining the ignition advance angle or retard angle and completing the engine timing adjustment; the knurling 9 not only facilitates manual fine adjustment, but also improves the structural strength, ensuring the stability and service life of the tool.

[0033] The scope of protection of this invention is defined by the claims. The specific embodiments described above are merely illustrative and not intended to limit the invention. Without departing from the core technical solution of this invention, those skilled in the art can make equivalent substitutions or simple modifications to the thread specifications of the sleeve 3, the dimensions of the hexagonal square head 7 / square hole 8, the knurling pattern of the knurling 9, the type of the instrument 1 (dial indicator, micrometer indicator, etc.), the material and dimensions of the probe 2, etc. For example, the pitch of the external thread 6 can be adjusted to 0.5mm or 1.5mm, the side length of the hexagonal square head 7 can be adjusted to 12mm or 16mm, and the side length of the square hole 8 can be adjusted to 8mm or 12mm. All such modifications should fall within the scope of protection of this invention.

Claims

1. A piston timing adjustment instrument, characterized in that, include: The measuring body includes instruments and probes; Sleeve; The probe is connected to the bottom of the instrument and is set through the sleeve rod; A fastening hole is provided on the outer periphery of the end of the sleeve near the instrument. A fastener is installed in the fastening hole. The sleeve and the probe are coaxially connected by the cooperation of the fastener and the fastening hole. The end of the sleeve rod away from the instrument is provided with an external thread, and the sleeve rod is directly screwed into the cylinder head mounting position through the external thread to achieve fixation; The sleeve has a hexagonal square head and / or a square hole on its outer peripheral wall above the external thread.

2. The piston timing adjustment instrument as described in claim 1, characterized in that: The outer peripheral wall of the sleeve is knurled.

3. The piston timing adjustment instrument as described in claim 2, characterized in that: The knurling covers the fastening holes and the mounting area of ​​the fasteners.

4. A piston timing adjustment instrument as described in any one of claims 1 to 3, characterized in that: The hexagonal square head and the sleeve are integrally formed.

5. A piston timing adjustment instrument as described in any one of claims 1 to 3, characterized in that: The square hole is a square through hole that penetrates the radial direction of the sleeve rod.

6. The piston timing adjustment instrument as described in claim 1, characterized in that: The pitch of the external thread is 1.5 mm.

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