JPS6123808Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an engine rotation detection sensor installed using a flywheel housing.

Conventionally, the structures shown in FIGS. 1 and 2 are known as mounting structures for this type of sensor. In FIG. 1, which is a partially cutaway schematic side view of the engine, a flywheel housing 3 is fixed to the right end surface of the cylinder block 1 with a gear case 2 in between.
A flywheel 6 is attached to the end of the crankshaft 5 within the housing 3. The pinion 9 of the starter 7 is attached to the flywheel housing 6.
A ring gear 10 for meshing with is fixed,
As shown in FIG. 2, which is a schematic cross-sectional view of FIG. 1, a rotation detection sensor 1 detects the rotation speed of the gear 10.
1 is attached to the peripheral wall 12 of the housing 3.
The sensor 11 is a device configured to detect the passage of the teeth of the gear 10 using, for example, magnetism. It is positioned and fixed based on the outer circumferential surface 13 of 12. However, since the sensor 11 needs to be placed close to the outer periphery of the gear 10, if the small-diameter gear 10 is used in the above configuration, a large sensor 11 is used and the tip of the sensor 11 is placed close to the outer circumference of the gear 10. It must be located closer to the center, and the cost increases by the increase in size. Moreover, the housing outer circumferential surface 13, which serves as the mounting reference surface for the sensor 11, has a low finish accuracy, so if the outer circumferential surface 13 is used as is, the mounting precision of the sensor 11 will also be low. It is necessary to finish the process with , which increases the cost.

The present invention focuses on the fact that the surface on the gear case side of the outer surface of the flywheel housing is machined to form a mating surface with the case and a starter mounting surface. The rotation detection sensor can be installed using this method, thereby reducing the machining cost of the sensor mounting reference surface, and
This is intended to improve mounting accuracy and is constructed as follows.

That is, the present invention fixes one end face of the gear case to the end face of the cylinder block, fixes the flywheel housing to the other end face of the gear case,
A machined surface is provided on the end face of the flywheel housing on the gear case side, and the machined surface forms a mating surface for the gear case, and the machined surface is used to mount the starter mounting seat and rotation detection sensor in the part that extends outward from the gear case. The rotation detection sensor is attached to the rotation detection sensor mounting seat, and the starter ring gear is attached to the flywheel in the flywheel housing. It is characterized in that the rotation detection sensor is placed opposite to the side surface of the tooth.

Next, embodiments will be described with reference to the drawings. The explanation is as follows.

In FIG. 3, parts corresponding to those in FIG. 1 are given the same reference numerals. The outer surface of the flywheel housing 3 on the cylinder block 1 side has a flat machined surface 20 that is aligned with the crankshaft center O-O.
It is formed at right angles to. The processed surface 20 serves as a mating surface 21 for the end surface of the gear case 2 and a mounting seat 22 for the starter 7. As shown in FIG. 4, which is a partial view in the − arrow direction of FIG.
It is located on the outside of 1 (the side far from the crankshaft center O) and on the diagonally lower side. The machining surface 20 is the lower end of the housing 3 from the mounting seat 22 (the part directly below the center O)
Part 2 of a small area extending obliquely downward toward
3, and the portion 23 is provided with a screw hole 25 passing through the end wall of the housing 3.

As shown in FIG. 5, which is a cross-sectional view of FIG. are opposed to the side surfaces of with a predetermined gap 1 in between. sensor 2
The hexagonal portion 29 at the base end is located outside the housing 3, and by bringing the annular end surface of the head 29 into contact with the processing surface portion 23, the mounting posture of the sensor 26 is maintained accurately. That is, the machined surface portion 23 serves as a mounting reference surface for the sensor 26.

Although not shown, one end of a signal cable is connected to the sensor 26 outside the housing 3, and the other end of the cable is connected to an electronic counter. The electronic counter electrically processes the pulses sent from the sensor 26 and displays it on the rotation display section as the engine speed. The pulses are also detected by the sensor 26 on the individual teeth 2 of the gear 10.
7 is detected magnetically or optically, and one pulse is generated each time the tooth 27 passes in front of the tip of the sensor 26.

As explained above, according to the present invention, since the rotation detection sensor 26 for detecting the rotation speed of the ring gear 10 (rotating body) in the flywheel housing 3 is attached to the machined surface 20 of the housing 3, the machined surface 20 can be processed with high accuracy. The sensor 26 can be accurately positioned based on the . Furthermore, since the sensor 26 is placed opposite the side surface of the teeth 27 of the ring gear 10, the following effects can be obtained.
In other words, the axial positional accuracy of the ring gear 10 is determined by the thrust clearance of the crankshaft and the machining accuracy of the flywheel 6, as shown in FIG. The axial positioning accuracy of the ten teeth 27 is high. On the other hand, since the sensor 26 is attached based on the machined surface as described above, the parallelism of the sensor 26 to the side surface of the tooth 27 is high. Furthermore, by inserting an adjustment shim or the like, the gap l between the two can be easily and accurately set. Therefore sensor 2
By arranging the sensor 26 to face the tooth side surface of the gear 10, the position and attitude of the sensor 26 relative to the tooth side surface can be set with extremely high precision.

Furthermore, by arranging the sensor 26 to face the tooth side of the ring gear 10, even if a small diameter gear 10 is used, it is only necessary to change the position of the sensor 26, and there is no need to use a large sensor 26. Therefore, an increase in the cost of the sensor 26 can be prevented.

Furthermore, the housing 3 is provided with a machined surface 20 that serves as a mating surface 21 with the gear case 2 and a mounting seat 22 of the starter 7, and a part of the machined surface 20 is used to form the mounting seat of the sensor 26. There is no need to process the dedicated mounting seat for sensor 26 in a separate process from other surfaces. Processing costs can be reduced.

Moreover, since the machined surface portion 23 for the sensor 26 is adjacent to the mounting seat 22 of the starter 7 in the circumferential direction centering on the crankshaft, the sensor 26
Compared to the case where the machining surface portion for the starter 7 is provided apart from the mounting seat 22 of the starter 7, the movement range of the tool during machining can be narrowed and the machining work can be simplified.

Further, as described above, by arranging the machined surface portion 23 adjacent to the mounting seat 22, the following advantages also arise. That is, the sensor 26 must be installed near the pitch circle of the ring gear 10 (the circle marked 10 in FIG. 4), must be installed outside the gear case 2 for wiring, and must be installed outside the gear case 2. In order to facilitate the work, it is preferable to provide it on the side of the housing 3 rather than on the lower end. On the other hand, since the starter 7 is located at a position that satisfies each of the above conditions, by placing the processed surface portion 23 for the sensor adjacent to the starter mounting seat 22, the sensor 26 can be mounted while satisfying each of the above conditions. This allows the sensor 26 to be installed at the optimum position without any problems. In short, by setting the position of the sensor 26 as described above, the position of the sensor 26 can be determined almost automatically at the design stage, and the work of setting the position of the sensor 26 can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway schematic side view of the conventional example, Fig. 2 is a schematic cross-sectional view of Fig. 1, Fig. 3 is a partial cross-sectional view of the embodiment of the present invention, and Fig. 4 is a - arrow view of Fig. 3. The partial view, FIG. 5, is a cross-sectional view taken from FIG. 1... Cylinder block, 2... Gear case,
3... Flywheel housing, 7... Starter, 10... Ring gear, 20... Machining surface,
21...Mating surface, 22...Starter mounting seat,
23... Part (sensor mounting seat), 26... Rotation detection sensor, 27... Teeth.

Claims (1)

[Scope of utility model registration request] One end face of the gear case is fixed to the end face of the cylinder block, a flywheel housing is fixed to the other end face of the gear case, a machined surface is provided on the end face of the flywheel housing on the gear case side, and the machined surface is used as a mating surface for the gear case. The above-mentioned machined surface forms a mounting seat for the starter and a mounting seat for the rotation detection sensor in the part that extends outward from the gear case, and both mounting seats are placed adjacent to each other in the circumferential direction around the crankshaft. A rotation detection sensor for an engine, characterized in that a rotation detection sensor is attached to a mounting seat of the detection sensor, and the rotation detection sensor is opposed to a side surface of teeth of a starter ring gear attached to a flywheel in a flywheel housing.