JP6477291B2 - Sensing ring - Google Patents

Description

  The present invention relates to a sensing ring attached to a vehicle shaft.

  Conventionally, as a structure for detecting the rotation angle and rotation speed of engines, transmissions, camshafts, etc. mounted on vehicles, a gear-shaped sensing ring is fixed to a shaft body (rotating shaft), and an electromagnetic field in the vicinity of the gears It is known that the phase and angular velocity of a shaft body are acquired by using the change of the above. For example, in an electromagnetic pickup type rotational speed detection device, a coil is disposed in the vicinity of a gear formed of a magnetic material, and the angular speed of the sensing ring is calculated based on the pulse interval of the induced electromotive force generated in the coil.

  In the eddy current type rotational speed detection device, an impedance corresponding to the distance between the gear and a coil disposed in the vicinity of the gear is detected, and the angular speed of the sensing ring is calculated based on the change. On the outer peripheral portion of the sensing ring used in these rotational speed detection devices, there are provided tooth portions arranged at a constant phase interval, missing tooth portions for providing a phase reference point, and the like (Patent Documents 1 and 2). reference).

JP2009-019691 JP 2010-216455 A

  By the way, since the sensing ring is a member fixed integrally with the shaft body, it has a property of easily generating vibration due to a mechanical vibration force. For example, in a sensing ring fixed to a crankshaft of an engine, flexural vibration can occur due to an excitation force such as an inertial force of a piston or an explosion pressure in a cylinder. Also, the same flexural vibration can occur in the sensing ring fixed to the transmission or the camshaft. Therefore, it is desirable that the eigenvalue (natural frequency, natural frequency) of each sensing ring is set sufficiently higher than the frequency of the excitation force that can be input to the sensing ring.

  A simple method for increasing the eigenvalue of the sensing ring is to increase the rigidity of the sensing ring by increasing the plate thickness. In general, the eigenvalue increases as the rigidity of the member increases. Therefore, the occurrence of resonance can be suppressed by increasing the thickness of the sensing ring. However, as the plate thickness is increased, the component weight increases and the fuel consumption deteriorates. That is, increasing the eigenvalue of the sensing ring and reducing the weight are in a trade-off relationship, and there is a problem that it is difficult to improve both of them simultaneously.

  One of the objects of the present case has been invented in view of the above problems, and is to provide a sensing ring that can be reduced in weight while suppressing the occurrence of resonance. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

  (1) The sensing ring disclosed here is a hollow disk-shaped sensing ring that is attached to a shaft body of a vehicle and has a gear formed on the outer periphery for obtaining a signal corresponding to the rotational speed of the shaft body. The sensing ring has a circular opening hole drilled in the center of the sensing ring, and a plurality of attachment holes through which a fixture for fixing the sensing ring to the shaft body is inserted. Moreover, the expansion part formed by expanding the said opening hole outside from between the two attachment holes adjacent to the circumferential direction is provided. The radial width (ring width) from the outer edge of the enlarged portion to the outer periphery has a maximum value at the boundary between the opening hole and the enlarged portion, and is minimum only at the center portion of the span between the two mounting holes. Has a value.

  (2) It is preferable that the width has a characteristic of monotonically increasing from the minimum value to the maximum value as it moves in the circumferential direction from the center portion of the span. Here, “monotonically increasing” means that the width increases without taking a constant value and without decreasing when the angle with respect to the center of the sensing ring is changed. To do. For example, the amount of increase (inclination) per unit angle always increases in a positive state. That is, it is preferable that a value obtained by differentiating the width expressed by the function of the angle with respect to the angle in a section from the minimum value to the maximum value is always a positive value.

  (3) Preferably, the width is given by a linear function of an angle with respect to the center of the sensing ring. That is, it is preferable that a value obtained by differentiating the width expressed by the function of the angle with respect to the angle in a section from the minimum value to the maximum value becomes a constant value. Alternatively, the width is preferably given as a quadratic function of an angle with respect to the center of the sensing ring.

  According to the disclosed sensing ring, the natural frequency per unit mass can be increased, and the weight can be reduced while suppressing the occurrence of resonance.

It is a figure which shows the sensing ring as embodiment. (A) is a graph showing the relationship between the ring width W and the angle θ in the sensing ring of FIG. 1, and (B) is a comparative example [of the ring width W and the angle θ in the sensing ring of FIG. Graph showing the relationship]. It is a figure for demonstrating the shape of a sensing ring, (A)-(C) is a comparative example, (D) is the sensing ring of FIG. It is a graph which shows the relationship between mass and an eigenvalue. (A)-(E) are the graphs which show the relationship between the ring width W and angle (theta) in the sensing ring as a modification.

  A sensing ring as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof. Further, they can be selected as necessary, or can be appropriately combined.

[1. Constitution]
FIG. 1 is a diagram showing a sensing ring 1 for an engine speed sensor (for a crank angle sensor). This sensing ring 1 is a hollow disk-shaped member attached to a crankshaft 8 (shaft body) of an engine mounted on a vehicle. On the outer periphery 9 of the sensing ring 1, a gear for obtaining a signal corresponding to the rotation speed and rotation angle of the crankshaft 8 is formed. The individual tooth portions 5 constituting the gear are arranged in a row so as to be equally spaced in the circumferential direction.

  Further, a part of the outer periphery 9 is provided with a missing tooth portion 6 where the tooth portion 5 is not disposed. The missing tooth portion 6 is a portion for providing a reference for the rotation angle (phase). A coil for detecting a change in the electromagnetic field is disposed in the vicinity of the gear. By detecting a change in induced electromotive force or impedance generated in the coil, the rotational speed of the crankshaft 8 (a value corresponding to the engine speed per unit time) can be calculated.

The sensing ring 1 is provided with a mounting hole 2, an opening hole 3, and an enlarged portion 4.
The mounting hole 2 is a round hole through which a fixture (bolt, nut, press-fit fixing pin, etc.) for fixing the sensing ring 1 to the crankshaft 8 is inserted. As shown in FIG. 1, the attachment holes 2 are provided at at least two or more positions, preferably at three or more positions. The fixture inserted through the mounting hole 2 is fastened and fixed with bolts to a pulley fixed to the crankshaft 8, a mounting seat of the sensing ring 1, and the like.

  The opening hole 3 is a circular hole drilled inward of the mounting hole 2 and is drilled in the center of the sensing ring 1 as indicated by a broken line in FIG. The crankshaft 8 (or a mounting seat fixed thereto) is inserted into the opening hole 3. The center C of the opening hole 3 is arranged so as to coincide with the center of the sensing ring 1 and coincide with the center of the crankshaft 8. In addition, the diameter of the opening hole 3 is set to a dimension that ensures a predetermined mounting allowance M between the opening hole 3 and the mounting hole 2.

  The enlarged portion 4 is a portion in which the opening hole 3 is partially enlarged to the outside of the sensing ring 1. The position where the enlarged portion 4 is provided is set within a range sandwiched between two mounting holes 2 adjacent in the circumferential direction. In the example shown in FIG. 1, since there are three positions sandwiched by the three mounting holes 2, the enlarged portion 4 is provided so as to bulge in the three directions from the center C of the opening hole 3. Here, a portion of the outer edge of the opening hole 3 where the enlarged portion 4 is not formed is referred to as a “fitting portion 7”. The fitting portion 7 is a portion into which the crankshaft 8 (or a mounting seat fixed thereto) is fitted and fixed. As a result, the crankshaft 8 is gripped and restrained from three directions, and the fixed state is stabilized.

  Further, the dimension in the radial direction from the outer edge of the enlarged portion 4 and the fitting portion 7 to the outer periphery 9 of the sensing ring 1 is referred to as “ring width W (width)”. The outer periphery 9 of the sensing ring 1 is a portion corresponding to the outer peripheral end of the sensing ring 1 excluding the tooth portion 5. In the present embodiment, the outer edge portion of the disk whose radius is the distance from the center C to the missing tooth portion 6 is the outer periphery 9 of the sensing ring 1. In addition, since the space | interval of two concentric circles becomes a constant value, the ring width W in the fitting part 7 becomes a constant value. On the other hand, the ring width W in the enlarged portion 4 changes according to the rotation angle.

The ring width W of the present embodiment has a maximum value W ₂ at the boundary X between the opening hole 3 and the enlarged portion 4 and has a minimum value W ₁ only at the center portion Y of the span. As shown in FIG. 1, the boundary X is a portion where the outline of the opening hole 3 and the enlarged portion 4 intersects with the enlarged portion 4 when the sensing ring 1 is viewed from the front (as viewed in the extending direction of the center C). This is a portion that becomes a boundary with the joint portion 7). Here, if the distance from the center C to the outer periphery 9 is set to D _{1 and} the radius of the opening hole 3 is set to D ₂ , the maximum value W ₂ is D ₁ −D ₂ .

The span center portion Y is a position where the distances between the two attachment holes 2 are equal in a portion sandwiched between the two attachment holes 2 adjacent to each other. As shown in FIG. 1, when a straight line passing through the center of each mounting hole 2 from the center C is drawn, each outer periphery 9 divided by these straight lines is called a “span”, and each length is Let L be L. The span center portion Y is the center portion of the span. Note that when the angle between the two adjacent mounting holes 2 and the center C is θ ₁ , the position through which the angle bisector passes may be defined as “span central portion Y”.

FIG. 2A is a graph illustrating the relationship between the angle θ (phase) with respect to the center C and the ring width W. Here, it is assumed that the angle θ is defined with reference to a straight line N passing through the center C and the hole core of one mounting hole 2. Ring width W of the fitting portion 7 is the maximum value W _2. On the other hand, the ring width W in the enlarged portion 4 has a characteristic of monotonously increasing from the minimum value W ₁ to the maximum value W _{2 as} it moves in the circumferential direction from the span center Y. The positions where the ring width W becomes the minimum value W ₁ are only the three span center portions Y.

As shown in FIG. 2 (A), for example, sections theta ₂ ~ ring width W of (θ _1/2) is given by a linear function of the angle theta, the section _{(θ 1/2) ~ (} θ 1 -θ 2) Is also given by a linear function of the angle θ. In any section, the contour shape of the enlarged portion 4 is set so that the ring width W increases from the minimum value W ₁ to the maximum value W ₂ with a constant inclination with respect to the increase / decrease of the angle θ. The minimum value W ₁ at the midspan portion Y of the three places are all set to the same value. In addition, as shown in FIG. 1, the outline shape of the opening hole 3 and the enlarged portion 4 of the sensing ring 1 is a symmetrical shape with respect to the straight line N (or a rotationally symmetric shape with respect to the center C) in consideration of balance. Is preferred.

[2. Comparative example]
3A to 3C are diagrams showing sensing rings 11, 21, and 31 as comparative examples, and FIG. 3D is a diagram showing the sensing ring 1 described above.
In the sensing ring 11 shown in FIG. 3A, the size of the enlarged portion 14 is reduced as compared with the sensing ring 1 described above. The shape of the enlarged portion 14 is a shape slightly enlarged from the opening hole 3 in the left and right directions, and the ring width W in the enlarged portion 14 is substantially the same as the ring width W in the fitting portion 7 (slightly smaller dimension). ).

  A sensing ring 21 shown in FIG. 3B is obtained by drilling a plurality of round holes 22 in the sensing ring 11 shown in FIG. The shape of the enlarged portion 24 is substantially the same as that of the enlarged portion 14 described above. The round hole 22 is continuously provided so as to surround the opening hole 3 over the entire outer periphery of the opening hole 3. The distance between the adjacent round holes 22 is set to a dimension that ensures a predetermined mounting allowance M, for example. Further, the distance between the round hole 22 and the mounting hole 2, the distance from the round hole 22 to the outer periphery 9, and the distance from the round hole 22 to the opening hole 3 (the fitting portion 7 and the enlarged portion 24) are also predetermined. Is set to a dimension that secures the mounting allowance M.

A sensing ring 31 shown in FIG. 3C is obtained by extending a portion of the enlarged portion 34 where the ring width W is the minimum value W _{1 in the} circumferential direction with the span central portion Y as the center. That is, the sensing ring 31 is provided with a section in which the ring width W is the minimum value W ₁ and the gradient of change of the ring width W with respect to the angle θ is zero. The relationship between the angle θ and the ring width W in the sensing ring 31 is illustrated in FIG. The ring width W in the section θ ₂ to (θ ₁ −θ ₂ ) corresponding to the enlarged portion 34 takes the minimum value W ₁ over a wide range, and the section (θ ₁ −θ ₂ ) to (θ ₁ ) corresponding to the fitting portion 7. The ring width W of + θ ₂ ) takes the maximum value W ₂ . That is, the section in which the ring width W is the minimum value W ₁ is provided not only in the span center portion Y but over almost the entire span L.

[3. Analysis result]
FIG. 4 is a graph showing the result of analyzing the relationship between the mass and the natural frequency for a predetermined material and plate thickness by applying a known eigenvalue analysis method to the sensing rings 1, 11, 21, and 31 described above. . Reference signs A to C in the graph correspond to the sensing rings 11, 21, and 31, respectively, and reference sign D corresponds to the sensing ring 1.

  The sensing ring 11 with the symbol A has a shape in which the area of the enlarged portion 14 is smaller than the others and the mass of the member is most likely to increase. Thereby, in order to acquire a predetermined natural frequency, it can be read that the mass must be increased more than others. On the other hand, the sensing ring 21 with the symbol B can have a smaller mass than the sensing ring 11 with the symbol A because the plurality of round holes 22 are perforated. However, it can be seen that by drilling the round hole 22, the rigidity is likely to decrease, and the natural frequency decreases overall.

The sensing ring 31 with the symbol C has a shape in which an enlarged portion 34 is formed outward from the opening hole 3. In this case, the cross section close to the center C is omitted in comparison with the sensing ring 21 with the symbol B. That is, since a cross section at a position away from the center C is secured, the rigidity is relatively less likely to be lower than that of the symbol B. However, since the range of the enlarged portion 34 is wide and the section in which the ring width W is the minimum value W ₁ is provided over almost the entire span L, the rigidity is slightly insufficient compared to the sensing ring 11 of the symbol A, and the natural frequency Will be lower overall.

On the other hand, in the sensing ring 1 with the symbol D, the shape of the enlarged portion 4 is slightly smaller than the sensing ring 31 with the symbol C, and is formed in a shape having the minimum value W ₁ only in the span center portion Y. As a result, the cross-sectional secondary moment is increased as compared with the case where the enlarged portion 34 is shaped like the sensing ring 31 of the symbol C, so that the rigidity is increased and the natural frequency is increased. Thereby, the mass for obtaining a predetermined natural frequency is reduced, and the weight of the member can be reduced.

  In addition, the sensing ring 1 with the symbol D has a characteristic that the amount of change in the natural frequency per unit mass (gradient of the graph) is larger than the others. This means that the structure shown in FIG. 3D can raise the natural frequency more efficiently than the structure shown in FIGS. For example, when the amount of increase in mass required when it is desired to increase the natural frequency by another 10 Hz at the design stage of the sensing ring 1 is calculated, the structure shown in FIG. The structure shown in D) is smaller. Moreover, the width of the natural frequency that can be increased when an allowable amount of increase in mass is given is shown in FIG. 3D rather than the structure shown in FIGS. The structure is larger. In this way, since the fluctuation ratio of the natural frequency with respect to the mass change increases, the degree of freedom in design and adaptability to specification changes are dramatically improved.

[4. effect]
(1) In the sensing ring 1 described above, the ring width W is set so that only the span center portion Y has the minimum value W ₁ and the boundary portion X between the enlarged portion 4 and the opening hole 3 has the maximum value W _2. The Thereby, the fluctuation | variation ratio of the natural frequency with respect to mass change can be raised. Therefore, the amount of mass increase for increasing the natural frequency can be reduced, and the weight of the member can be reduced while suppressing the occurrence of resonance.

  Further, in the sensing ring 1 described above, the portion where the ring width W is minimum is only one point for each span. In other words, since the ring width W is the smallest at the span center Y only, the cross-sectional secondary moment can be increased and the rigidity is increased compared to the structure shown in FIG. Cheap. Thereby, the mass for obtaining a predetermined natural frequency is reduced, and the weight of the member can be reduced.

On the other hand, the fitting portion 7 with the ring width W having the maximum value W ₂ is provided with a constant width at both ends of each span, so that the sensing ring 1 can be stably fixed to the crankshaft 8 and the rigidity can be increased. Can be increased. Therefore, the natural frequency can be easily increased.
Furthermore, compared with the structure shown in FIG. 3C, since the portion where the ring width W is minimized is small, the ring width W in the vicinity of the mounting hole 2 can be relatively large. Thereby, the rigidity around the fixed part of the sensing ring 1 can be increased, and the natural frequency can be easily increased.

(2) In the sensing ring 1 described above, as shown in FIG. 2A, the ring width W changes from the minimum value W ₁ to the maximum value W _{2 as} it moves in the circumferential direction from the span center Y. Has a monotonically increasing characteristic. That is, the contour shape of the enlarged portion 4 is set so that the ring width W gradually increases from the span center portion Y toward the vicinity of the attachment hole 2 (so as not to decrease). Thereby, the ring width W can be made larger as the distance to the mounting hole 2 is closer, and the cross-sectional area can be made smaller while suppressing a decrease in rigidity. Therefore, it is possible to provide the sensing ring 1 that is light and hardly causes resonance.

  (3) In the sensing ring 1 described above, as shown in FIG. 2A, the ring width W is given by a linear function of the angle θ. Thereby, the outline shape of the expansion part 4 can be characterized using the spiral arc of a simple shape. Therefore, not only a resonance suppression effect and a weight reduction effect can be obtained, but also the productivity of the sensing ring 1 can be improved.

(4) In the sensing ring 1 described above, the ring widths W at the three span center portions Y are all the minimum value W ₁ and are the same value. Thus, it is possible to ensure the minimum value W ₁ or more ring width W over the entire circumference of the sensing ring 1, it is possible to secure the rigidity in the vicinity of the outer circumference 9. Thereby, weight can be reduced, suppressing generation | occurrence | production of the resonance of the sensing ring 1. FIG.

[5. Modified example]
In the above-described embodiment, the sensing ring 1 in which the ring width W is given by a linear function of the angle θ is illustrated as shown in FIG. 2A, but the relationship between the ring width W and the angle θ is not limited to this. . For example, as shown in FIGS. 5A and 5B, the contour shape of the enlarged portion 4 may be set so that the shape of the graph representing the relationship between the ring width W and the angle θ is a curved shape. . Further, as shown in FIG. 5C, the ring width W of the enlarged portion 4 may be a shape given by a quadratic function of the angle θ. At least the ring width W is set so as to have the minimum value W ₁ only in the span center portion Y, and the ring width W is monotonously increased from the span center portion Y toward the peripheral portion of the mounting hole 2. The same effect as the embodiment is achieved.

  Moreover, although the sensing ring 1 in which the attachment hole 2 was provided in three places was shown in FIG. 1, the number of the attachment holes 2 can be set arbitrarily. In the case where the mounting holes 2 are provided at two locations, there are two spans between them, so the enlarged portions 4 are also provided at two locations. If the number of mounting holes 2 is four, the enlarged portions 4 may be provided at four locations.

Incidentally, the fitting portion 7 in the above embodiment, as shown in FIG. 2 (A), has provided a range of intervals _{(θ 1 -θ 2) ~ (} θ 1 + θ 2), each span Alternatively, the maximum value W ₂ may be taken only at the end. That is, as shown in FIG. 5D, the width of the fitting portion 7 may be narrowed. Further, as shown in FIG. 5E, the relationship between the ring width W and the angle θ may be different for each span. By providing at least a portion where the crankshaft 8 (or a mounting seat fixed to the crankshaft 8) is fitted and fixed in the vicinity of the mounting hole 2, the crankshaft 8 can be gripped and restrained from the periphery thereof. The fixed state can be further stabilized.

1 Sensing ring 2 Mounting hole 3 Opening hole 4 Enlarged part 5 Tooth part 6 Notch part 7 Fitting part 8 Crankshaft 9 Outer circumference W ₁ Minimum value W ₂ Maximum value X Boundary Y Span center

Claims (3)

A hollow disc-shaped sensing ring that is attached to a shaft body of a vehicle and has a gear formed on the outer periphery for obtaining a signal corresponding to the rotational speed of the shaft body,
A circular opening hole drilled in the center of the sensing ring;
A plurality of mounting holes through which a fixture for fixing the sensing ring to the shaft body is inserted;
An enlarged portion formed by enlarging the opening hole to the outside from between two mounting holes adjacent in the circumferential direction,
The width in the radial direction from the outer edge of the enlarged portion to the outer periphery has a maximum value at the boundary between the opening hole and the enlarged portion, and has a minimum value only at the center portion of the span between the two mounting holes. Sensing ring characterized by 2. The sensing ring according to claim 1, wherein the width has a characteristic of monotonically increasing from the minimum value to the maximum value as it moves in a circumferential direction from the center portion of the span. The sensing ring according to claim 1, wherein the width is given by a linear function or a quadratic function of an angle with respect to a center of the sensing ring.

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