JP2012136996A - Crank angle detection device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of an internal combustion engine by reducing the length in the width direction of the internal combustion engine, and to reduce the number of components and assembly manhours.SOLUTION: A crank angle detection device 40 for an internal combustion engine includes a crankshaft 25 arranged in an engine 16 as an internal combustion engine, and a crank angle sensor 41 for detecting a rotation angle of the crankshaft as a crank angle. The crank angle detection device is structured such that a primary drive gear 32 is arranged rotationally integrated with a crank weight 38A of the crankshaft 25; the primary drive gear 32 transmits power to an adjacent primary driven gear 33 and includes a cutout part 42 having a height difference h; and the crank angle sensor 41 can detect the crank angle by detecting the primary drive gear 32 on the basis of the cutout part 42.

Description

  The present invention relates to a crank angle detection device for an internal combustion engine that detects a crank angle of the internal combustion engine.

  As shown in FIG. 5, in the crank angle detection device 100 for an internal combustion engine (engine), the crank angle sensor 103 conventionally detects a protrusion or a depression on the outer periphery of the sensing rotor 102 attached to the shaft end of the crankshaft 101. Thus, the rotation angle of the crankshaft 101, that is, the crank angle is detected.

  The crank angle sensor 103 is installed inside the engine side cover 105 at the side of the crankcase 104. The rotational force of the crankshaft 101 is transmitted to the primary driven gear 109 via the primary drive gear 108 provided on the crankshaft 101.

  Further, in Patent Document 1, an arcuate segment in which teeth for crank angle detection are formed on the outer periphery is attached to the crankweight of the crankshaft, and the teeth of the arcuate segment are detected by the crank angle sensor when the crankshaft rotates. Thus, a crank angle detection device for detecting the rotation angle (crank angle) of the crankshaft is disclosed.

Japanese Patent Laid-Open No. 10-184434

  However, in the crank angle detection device 100 shown in FIG. 5, since the sensing rotor 102 is attached to the shaft end of the crankshaft 101, the axial length of the engine increases, making it difficult to reduce the size and weight of the engine. In addition, it becomes difficult to ensure the rigidity of the crankshaft 101 and the crankcase 104.

  Moreover, since the sensing rotor 102 is attached to the crankshaft 101 using the washer 106 and the attachment bolt 107, the number of parts increases and the assembly man-hour also increases.

  Furthermore, the accuracy of crank angle detection by the crank angle sensor 103 is reduced due to the backlash of the gap for attaching the sensing rotor 102 to the crankshaft 101.

  In the case of an engine mounted on a motorcycle, the outer diameter of the sensing rotor 102 cannot be increased in order to secure the bank angle of the vehicle. Accordingly, since the peripheral speed of the protrusions or depressions on the outer periphery of the sensing rotor 102 becomes low, the crank angle sensor 103 may not be able to detect the crank angle with high accuracy, particularly when the crankshaft 101 rotates at a low speed.

  On the other hand, in the crank angle detection device described in Patent Document 1, a crank angle detection gear (bow segment) is required on the crankshaft in addition to the primary drive gear for power transmission and the cam drive sprocket. The number of parts and assembly man-hours will increase.

  The object of the present invention has been made in consideration of the above-mentioned circumstances, and it is possible to reduce the length in the width direction of the internal combustion engine to reduce the size and weight of the internal combustion engine, and to reduce the number of parts and assembly man-hours. An object of the present invention is to provide a crank angle detection device for an internal combustion engine that can be reduced.

  The present invention provides a crank angle detection device for an internal combustion engine having a crank shaft provided in an internal combustion engine and a crank angle sensor that detects a rotation angle of the crank shaft as a crank angle. The first gear is provided integrally with the rotation, and the first gear transmits power to the adjacent second gear and has a step portion having a height difference. The crank angle sensor is based on the step portion. As described above, the crank angle can be detected by detecting the first gear.

  According to the present invention, a step portion is provided in the first gear that is provided integrally with a part of the crankshaft, and the crank angle sensor detects the first gear on the basis of the step portion. Since the angle is detected, there is no need to provide a sensing rotor for detecting the crank angle at the end of the crankshaft. As a result, the length of the internal combustion engine in the width direction is shortened, and the internal combustion engine can be reduced in size and weight. Furthermore, since a sensing rotor is not required, the number of parts and the number of assembly steps can be reduced.

1 is a left side view showing a motorcycle equipped with an engine as an internal combustion engine to which an embodiment of a crank angle detection device for an internal combustion engine according to the present invention is applied. The right view which shows the engine of FIG. Sectional drawing which follows the III-III line | wire of FIG. The side view which shows the crankshaft of FIG. 3, a connecting rod, and a crank angle sensor. Sectional drawing which shows the sensing rotor, crank angle sensor, etc. which were attached to the conventional crankshaft.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a left side view showing a motorcycle equipped with an engine as an internal combustion engine to which an embodiment of a crank angle detection device for an internal combustion engine according to the present invention is applied. In the present embodiment, expressions of front and rear, top and bottom, and left and right are based on a passenger who rides the motorcycle.

  As shown in FIG. 1, a motorcycle 1 has a body frame 2, and a head pipe 3 is provided in front thereof. The head pipe 3 is provided with a steering mechanism 7 including a pair of left and right front forks 5, a handle bar 6 and the like which are provided with a suspension mechanism (not shown) and rotatably support the front wheel 4. Is steered so as to be pivotable left and right.

  On the other hand, the vehicle body frame 2 is, for example, of a twin tube type, and is expanded to the left and right immediately after the head pipe 3 and then serves as a main frame 8 that also serves as a pair of left and right tank rails extending parallel to each other and rearwardly downward. The pair of left and right center frames 9 connected to the rear end portions of the main frames 8 and extending substantially upward and downward, and the pair of left and right seat rails 10 extending rearward from the rear upper ends of the center frames 9 are provided. Configured.

  A fuel tank 11 is disposed above the main frame 8, and a rider seat 12A and a pillion seat 12B are disposed above and below the vehicle, respectively. Further, a pivot shaft 13 is installed substantially at the center lower portion of the center frame 9, and a swing arm 14 is pivotally attached to the pivot shaft 13 so as to be swingable around the pivot shaft 13, and a rear end is provided at the rear end of the swing arm 14. The wheel 15 is pivotally supported. An engine 16 as an internal combustion engine is disposed below the fuel tank 11 at the lower center of the vehicle body between the front wheels 4 and the rear wheels 15.

  Further, in the motorcycle 1, the front portion of the vehicle body is covered with a streamlined cowling 17 to reduce air resistance during traveling and to protect the rider from traveling wind pressure. 1 is an exhaust pipe that discharges exhaust gas from the engine 16, and an exhaust muffler 18B is connected to the rear end of the exhaust pipe 18A.

  As shown in FIGS. 2 and 3, the engine 16 is a four-cycle multi-cylinder engine, for example, a four-cycle parallel four-cylinder engine, and has an outer shape mainly composed of a head cover 19, a cylinder head 20, a cylinder block 21, and a crankcase 22. The The crankcase 22 is of a split type, and is composed of, for example, an upper crankcase 22A divided into two in the vertical direction in FIG. 2 and the cylinder block 21 provided separately, and a lower crankcase 22B. An oil pan 28 is installed below the lower crankcase 22B.

  The cylinder block 21 is arranged to be inclined slightly forward from the upright position, and the bearing portions 24 are divided into upper and lower parts inside the mating surface 23 of the upper crankcase 22A and the lower crankcase 22B. A crankshaft 25 extending in the width direction of the engine 16 is rotatably supported by these bearing portions 24.

  A large end portion 26A of a connecting rod 26 is connected to the crankshaft 25, and a piston 27 is connected to a small end portion 26B of the connecting rod 26 as shown in FIG. A piston 27 is accommodated in the cylinder block 21 so as to be slidable substantially in the vertical direction in the figure. A combustion chamber (not shown) is formed in the space between the cylinder head 20 and the piston 27. The piston 27 reciprocates by the combustion of the air-fuel mixture in the combustion chamber, and the reciprocating motion of the piston 27 is converted into rotational motion by the crankshaft 25.

  As shown in FIG. 2, in the crankcase 22, a counter shaft 29 and a drive shaft 30 are disposed behind the crankshaft 25, and a balancer shaft 31 is disposed in front of the crankshaft 25. Among them, the counter shaft 29 and the balancer shaft 31 are pivotally supported on the mating surface 23 of the upper crankcase 22A and the lower crankcase 22B together with the crankshaft 25. The crankshaft 25, the countershaft 29, the drive shaft 30, and the balancer shaft 31 extend in the width direction of the engine 16 (that is, the vehicle width direction of the motorcycle 1) and are accommodated in the crankcase 22.

  As will be described in detail later, the crankshaft 25 is provided with a primary drive gear 32 that is integrally rotated. The primary drive gear 32 meshes with a primary driven gear 33 that is rotatably supported by the countershaft 29. The counter shaft 29 is provided with a clutch mechanism 34 connected to the primary driven gear 33 at the shaft end, and is mounted with a plurality of stages of transmission drive gears (not shown). These mission drive gears mesh with a plurality of mission driven gears (not shown) mounted on the drive shaft 30. These mission drive gear and mission driven gear constitute a transmission mission mechanism together with a shift mechanism (not shown).

  The shaft end of the drive shaft 30 projects outside the crankcase 22, and a drive sprocket (not shown) is fixed to the shaft end of the drive shaft 30. A driven sprocket 35 is fixed to the rear wheel 15 as shown in FIG. 1, and a drive chain 36 is wound between the drive sprocket and the driven sprocket 35.

  Therefore, the rotational force of the crankshaft 25 of the engine 16 shown in FIGS. 1 and 2 (that is, the driving force of the engine 16) is transmitted to the counter shaft 29 via the primary drive gear 32, the primary driven gear 33, and the clutch mechanism 34, This is transmitted from the counter shaft 29 to the drive shaft 30 through the transmission transmission mechanism. The rotational force of the crankshaft 25 transmitted to the drive shaft 30 is transmitted to the rear wheel 15 via the drive sprocket, the drive chain 36 and the driven sprocket 35.

  In addition, a balancer driven gear 37 is provided on the balancer shaft 31 so as to rotate together with a balancer weight (not shown). The balancer driven gear 37 meshes with the primary drive gear 32 that also functions as a balancer drive gear. Accordingly, the balancer weight is rotated by the rotation of the crankshaft 25 via the primary drive gear 32 and the balancer driven gear 37, and together with the crankweight 38 (FIG. 3) provided on the crankshaft 25, the engine accompanying the reciprocating motion of the piston 27. 16 vibrations are reduced.

  By the way, the primary drive gear 32 as the first gear provided integrally with the crankshaft 25 is provided on the crank weight 38 as shown in FIGS. The primary drive gear 32 may be formed by directly cutting the crank weight 38 or may be formed by coupling a separately processed gear to the crank weight 38 by press-fitting or the like. As described above, the primary drive gear 32 meshes with the adjacent primary driven gear 33 and the balancer driven gear 37 as the second gear, and transmits the rotational force of the crankshaft 25 to the counter shaft 29 and the balancer shaft 31, respectively.

  Here, the crank weight 38 provided with the primary drive gear 32 is a crank located on the center side of the engine 16 among a pair of crank weights 38A and 38B provided on one end side (for example, the vehicle right end side) of the crankshaft 25. Weight 38A.

  As will be described later, when the cable not shown connected to the crank angle sensor 41 for sensing the primary drive gear 32 is considered, the position of the primary drive gear 32 is close to the outside of the engine 16. Is desirable. However, since it is effective to install the crank weights 38 at both ends of the crankshaft 25 from the viewpoint of suppressing vibrations of the engine 16, the crankweight 38 is positioned at the end of the crankshaft 25 of the crankweight 38A and the crankweight 38B. The crank weight 38B is intended to be the original crank weight. For these reasons, the position where the primary drive gear 32 is provided is the crank weight 38A described above.

  Now, the engine 16 of this embodiment includes a crank angle detection device 40 for an internal combustion engine. The crank angle detection device 40 includes a crank angle sensor 41 that detects the rotation angle of the crankshaft 25 as a crank angle, and the primary provided on the crankshaft 25 that is detected (detected) by the crank angle sensor 41. And a drive gear 32.

  The primary drive gear 32 is formed with a notch 42 as a step portion having a height difference h in the radial direction of the primary drive gear 32 at an arbitrary position in the circumferential direction. The notch 42 is formed by reducing the tooth width of one tooth or a plurality of teeth (for example, two teeth) in the primary drive gear 32 by the dimension e. For example, the height difference h is set to 10 mm, and the dimension e is set to 5 mm.

  The primary drive gear 32 is formed with a balancer hole 43 or a balancer recess as a weight balancer means at a position that is substantially point symmetric with the notch 42 with respect to the center of the gear diameter of the primary drive gear 32. Even when the notch 42 is formed in the primary drive gear 32 due to the presence of the balancer hole 43 and the like, the center of the inertia moment around the crankshaft 25 in the primary drive gear 32 is the center of the gear diameter of the primary drive gear 32. It almost agrees. Thereby, the weight balance at the time of rotation of the primary drive gear 32 is ensured favorably.

  The crank angle sensor 41 detects the primary drive gear 32 with reference to the cutout portion 42 of the primary drive gear 32, and measures the change in the magnetic field caused by the cutout portion 42, whereby the rotation angle of the crankshaft 25 (that is, the crank angle). Is detected. The crank angle sensor 41 is installed by being inserted into an opening 45 provided in a lower portion of the crankcase 22, that is, in the lower crankcase 22B.

  At this time, the detection unit 44 of the crank angle sensor 41 is opposed to the teeth of the primary drive gear 32, and the direction of the height difference h in the notch 42 provided in the primary drive gear 32 (that is, the primary drive gear 32). (Radial direction). Further, the detection portion 44 of the crank angle sensor 41 has a center position P (FIG. 3) within a range along the axial direction of the crankshaft 25 in the notch portion 42, that is, the tooth width direction of the primary drive gear 32 in the notch portion 42. It is arrange | positioned so that it may become in the range of the dimension e along.

  With the configuration as described above, the following effects (1) to (9) are achieved according to the present embodiment.

  (1) A notch 42 is formed in the primary drive gear 32 that is provided integrally with the crank weight 38A of the crankshaft 25, and the crank angle sensor 41 detects the primary drive gear 32 with reference to the notch 42. Detect the crank angle. For this reason, it is not necessary to provide a sensing rotor for detecting the crank angle (sensing rotor 102 in FIG. 5) at the end of the crankshaft 25. As a result, the length of the engine 16 in the width direction (that is, the width direction of the motorcycle 1) is shortened, and the engine 16 can be reduced in size and weight.

  (2) Since the crank angle sensor 41 detects the crank angle of the crankshaft 25 by detecting the primary drive gear 32 provided integrally with the crankshaft 25, the sensing rotor is not required. For this reason, mounting bolts and washers for mounting the sensing rotor (the mounting bolts 107 and washers 106 in FIG. 5) and the like are no longer necessary, and the number of parts and assembly man-hours can be reduced.

  (3) Since the crank angle sensor 41 directly detects the primary drive gear 32 provided integrally with the crankshaft 25 instead of the sensing rotor, the crank angle sensor 41 has a backlash for mounting the sensing rotor 102 on the crankshaft 25. There is no influence, and the detection accuracy of the crank angle sensor 41 can be improved.

  (4) Even when the bank angle of the motorcycle 1 is increased, the primary drive gear 32 can be set to have a larger outer diameter than the sensing rotor. For this reason, the peripheral speed of the primary drive gear 32 including the notch portion 42 is increased, and the waveform of the signal pulse becomes clear especially when the crankshaft 25 rotates at a low speed, and the detection accuracy of the crank angle sensor 41 is improved. be able to.

  (5) When the crank angle sensor 41 detects the primary drive gear 32 and detects the crank angle of the crankshaft 25, the notch 42 formed by reducing the tooth width of the primary drive gear 32 is used as a sensing reference. Yes. For this reason, for example, compared to the case where the convex portion protruding from the side surface of the primary drive gear 32 is used as a reference for sensing, the shape of components adjacent to the primary drive gear 32 is changed, and the arrangement position of the primary drive gear 32 is changed. This is advantageous in terms of component layout.

  (6) The primary drive gear 32 balances the weight of the primary drive gear 32 so that the center of the inertia moment around the crankshaft 25 in the primary drive gear 32 is the center of the gear diameter in the primary drive gear 32. Balancer holes 43 are provided. For this reason, the weight balance of the primary drive gear 32 at the time of rotation is ensured satisfactorily, and the primary drive gear 32 does not run out. As a result, it is possible to contribute to the reduction of the swing of the crankshaft 25.

  (7) The notch portion 42 provided in the primary drive gear 32 is formed with a height difference h in the radial direction of the primary drive gear 32, and the detection portion 44 of the crank angle sensor 41 is formed on the teeth of the primary drive gear 32. While facing each other, the cutout portion 42 formed in the primary drive gear 32 is positioned in the direction of the height difference h. For this reason, this embodiment is compared with the case where the notch is formed with a height difference in the tooth width direction of the primary drive gear 32 and the detection portion 44 of the crank angle sensor 41 is positioned in this height difference direction. In this case, the reduction in the tooth width of the primary drive gear 32 can be minimized. As a result, the strength of the primary drive gear 32 can be satisfactorily ensured also by the formation of the notch 42.

  (8) Since the crank angle sensor 41 is installed in the lower part of the crankcase 22, a radiator or an oil cooler (both not shown) disposed in front of the engine 16, an exhaust pipe 18A passing through the front of the engine 16, etc. The influence of heat due to can be avoided.

  (9) Since the detection position 44 of the crank angle sensor 41 is arranged within the range of the dimension e along the tooth width direction in the notch 42 of the primary drive gear 32, the detection position 44 of the crank angle sensor 41 is attached. Even when an error occurs, the detection accuracy of the crank angle sensor 41 can be prevented from being lowered.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this, A various deformation | transformation can be made in the range which does not deviate from the main point of this invention.

  For example, in the present embodiment, the step portion has been described as the case of the notch portion 42 formed by reducing the tooth width of the primary drive gear 32. However, the step portion is a convex portion protruding from the side surface of the primary drive gear 32. Alternatively, the crank angle sensor 41 may use this convex portion as a sensing reference. At this time, the crank angle sensor 41 has a position where the detection unit 44 is opposed to the teeth of the primary drive gear 32, or a position rotated by 90 degrees with respect to this position (that is, a position opposed to the side surface of the primary drive gear 32). The convex portions as the stepped portions may be detected by positioning them respectively.

16 engine (internal combustion engine)
22 Crankcase 25 Crankshaft 29 Countershaft 31 Balancer shaft 32 Primary drive gear (first gear)
33 Primary driven gear (second gear)
37 Balancer driven gear (second gear)
38, 38A Crank weight 40 Crank angle detection device 41 Crank angle sensor 42 Notch (step)
43 Balancer hole (weight balancer means)
44 Detector h Height difference P Center position

Claims (9)

In a crank angle detection device for an internal combustion engine, comprising: a crankshaft provided in the internal combustion engine; and a crank angle sensor that detects a rotation angle of the crankshaft as a crank angle.
A first gear is provided integrally with a part of the crankshaft, and the first gear transmits power to an adjacent second gear and includes a step portion having a height difference.
The crank angle detection device for an internal combustion engine, wherein the crank angle sensor is configured to detect the crank angle by detecting the first gear with reference to the stepped portion. 2. The crank angle detection device for an internal combustion engine according to claim 1, wherein the stepped portion is a notch formed by reducing a tooth width of the first gear. 2. The step portion is provided with a height difference in a radial direction of the first gear, and a detection portion of a crank angle sensor is positioned in the height difference direction of the step portion. The crank angle detection device for internal combustion engines described in 1. The first gear includes a weight balancer that balances the weight of the first gear so that the center of inertia around the crankshaft of the first gear is the center of the gear diameter of the first gear. The crank angle detection device for an internal combustion engine according to claim 1, further comprising means. 2. The crank angle detection device for an internal combustion engine according to claim 1, wherein the crank angle sensor is installed in a lower portion of a crankcase that houses a crankshaft. 2. The internal combustion engine according to claim 1, wherein, of the pair of crank weights provided on one end side of the crankshaft, a first gear is provided on the crank weight located on the center side of the internal combustion engine. Engine crank angle detection device. 2. The crank angle detection for an internal combustion engine according to claim 1, wherein the crank angle sensor is arranged such that a center position of a detection portion thereof is within a range along an axial direction of the crankshaft at the stepped portion. apparatus. 2. The crank angle detection device for an internal combustion engine according to claim 1, wherein the first gear is a primary drive gear that meshes with a primary driven gear as a second gear provided on the counter shaft. 2. The crank angle detection device for an internal combustion engine according to claim 1, wherein the first gear is a balancer drive gear that meshes with a balancer driven gear as a second gear provided on a balancer shaft.

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