JP6445285B2 - Low noise gear - Google Patents

Description

  The present invention relates to a low noise gear for reducing noise.

  The cam gear that opens and closes the engine valve opens and closes the intake and exhaust valves via the push rod and rocker arm. The cam gear receives a biasing force of a spring that biases the intake / exhaust valve in the closing direction in the rotational direction. Therefore, when the cam gear rotates to open and close the valve, torque variation occurs, and noise is generated between the cam gear and the meshed gear.

  The cam gear is generally made of a material having high hardness such as S53C (carbon steel for machine structural use), chrome steel, or chrome molybdenum steel. Therefore, the amount of attenuation with respect to the sound is small, and the high rattling noise continues to sound for a long time.

JP 2011-169269 A

  There is a scissor gear as a gear for reducing the rattling noise. However, the scissor gear eliminates play by applying torque to two identical and coaxial gears with a spring, and the gear itself has many parts and a complicated structure. In addition, since the scissor gear wears on the sliding surfaces of the two gears that slide on each other, it is necessary to replace the gears.

  Moreover, as a low noise gear, there exists a thing as shown, for example in patent document 1. FIG. In this low noise gear structure, the gear is divided into an inner member and an outer member, and an internal friction resistance is increased between the inner member and the outer member, and a vibration damping member for damping vibration is provided. Become. In this low noise gear structure, the gear is divided into three in the radial direction, and the structure is complicated.

  An object of the present invention is to provide a low-noise gear that can attenuate noise with a simple configuration.

  The low-noise gear that solves the above-described problems has a disk shape, a main body portion provided with a gear portion on the outer periphery, a vibration isolating plate having a natural frequency different from that of the main body portion, and the main body portion. And a holding portion that holds the side surface of the vibration-proof plate.

  According to the above configuration, the vibration isolating plate having a natural frequency different from that of the main body is attached to the holding portion, so that the gear and the gear mesh with each other, and the teeth of the main body generated when the teeth are struck by rotation. The vibration can be damped. Thereby, the noise which arises by torque fluctuation etc. can be reduced in a short time. With the above configuration, gear noise can be reduced with a simple configuration in which a vibration-proof plate is simply attached to the holding portion of the main body.

In the low noise gear, the holding portion may be provided in a groove portion provided in the main body portion, and the vibration-proof plate may be held by press-fitting on a side surface of the groove portion. In this case, the vibration isolating plate is free with respect to the bottom surface of the groove. Thereby, the plate can vibrate at a frequency different from that of the main body, and the vibration of the main body can be attenuated.
According to the said structure, the said vibration-proof plate can be easily attached by press fit.

In the low noise gear, the vibration isolation plate may be formed in an annular shape.
According to the said structure, the vibration generate | occur | produced over the said whole circular main-body part can be attenuate | damped effectively.

  In the low noise gear, the main body may be made of any one of high carbon steel, chrome steel, and chrome molybdenum steel, and the vibration isolation plate may be made of ductile cast iron. Moreover, it can form with a hot-rolled steel plate.

  According to the above configuration, the main body portion serving as a strength member is formed of a high-strength material, and the vibration isolating plate is formed of a material having a lower frequency than the main body portion, thereby maintaining physical strength. The vibration of the main body can be attenuated and noise can be reduced. In the case of a hot-rolled steel plate, the vibration-proof plate can be easily manufactured by press working.

  According to the above configuration, noise can be attenuated with a simple configuration.

It is a perspective view of a low noise gear. It is a top view of a low noise gear. It is sectional drawing of a low noise gear. It is a top view of the low noise gear shown as 2nd Embodiment. It is a top view of the low noise gear shown as 3rd Embodiment, and shows the example which press-fits an annular plate inside the outer periphery rim | limb. It is sectional drawing of the low noise gear shown as 4th Embodiment, and shows the example by which an annular plate is press-fitted between a pair of annular ribs. It is sectional drawing of the low noise gear shown as 4th Embodiment, and shows the example by which the annular plate was press-fitted on the outer side of the annular rib. It is sectional drawing of the low noise gear shown as 4th Embodiment, and shows the example by which the annular plate was press-fitted inside the annular rib.

Hereinafter, an embodiment of a low noise gear will be described with reference to FIGS.
(First embodiment)

  The low noise gear 1 shown in FIGS. 1 to 3 is applied to, for example, a cam gear that opens and closes an intake / exhaust valve via a push rod and a rocker arm. The low-noise gear 1 is a spur gear and has a disk-shaped main body 2 having a gear portion 3 formed on the outer periphery. The main body 2 is formed of a material having high hardness such as S53C (carbon steel for machine structure), chrome steel, or chrome molybdenum steel, and has a first natural frequency. The main body 2 is formed with a center hole 4 through which the camshaft is inserted at the center. The main body 2 has a first central recess 5 formed on one surface of the outer periphery of the center hole 4. The first central recess 5 is provided with a camshaft flange. On the other surface of the main body 2, a second central recess 7 in which an attachment member such as a set screw for attaching the low noise gear 1 to the camshaft is disposed on the outer periphery of the center hole 4. The first central recess 5 and the second central recess 7 are formed with an engaging portion 6 with which a knock pin 6a for preventing the low noise gear 1 from rotating with respect to the camshaft is engaged.

  On one surface of the main body 2, an annular protrusion 8 is formed continuously with the outer peripheral side of the first central recess 5, and an annular groove 9 is formed continuously with the outer peripheral side of the annular protrusion 8. Has been. A rim 12 is provided on the outer peripheral side of the annular groove portion 9, and the gear portion 3 is formed on the outer peripheral surface of the rim 12.

  An annular plate 11 serving as a vibration isolation plate is attached to the annular groove 9. In the annular groove 9, the portion adjacent to the outer periphery of the annular protrusion 8, that is, the bottom surface on the inner periphery side and the outer peripheral surface of the annular protrusion 8 serve as the holding portion 9 a of the annular plate 11. The holding portion 9a has a shape corresponding to the mounting surface of the annular plate 11, and is formed on a flat surface here. Moreover, the outer peripheral side of the holding | maintenance part 9a becomes the recessed part 9b deeper than an attachment surface. The annular plate 11 is press-fitted until the inner diameter thereof matches the outer diameter of the annular protrusion 8 and comes into contact with the bottom surface of the annular groove 9 in the holding portion 9a in the annular groove 9. Since the annular plate 11 is attached to the annular protrusion 8, that is, the inner peripheral side surface of the annular groove portion 9 by an interference fit, the annular plate 11 is prevented from falling off from the main body portion 2 due to vibration or the like. Further, in the annular groove portion 9, the annular plate 11 is not disposed on the outer peripheral side of the holding portion 9 a, and the recess 9 b is formed even after the annular plate 11 is disposed. The fastening allowance is appropriately set so that the annular plate 11 does not come off the main body 2 due to vibrations caused by normal use.

  The annular plate 11 is formed so that the thickness thereof substantially matches the depth of the annular groove portion 9, and the surface of the annular plate 11 is substantially flush with the top surface of the annular protrusion 8 when disposed in the annular groove portion 9. That is, when the top surface of the annular protrusion 8 and the top surface of the rim 12 are substantially the same, and the annular plate 11 is also attached to the holding portion 9a, the top surface of the annular protrusion 8 and the top surface of the rim 12 It does not protrude from. Therefore, the low noise gear 1 can prevent the annular plate 11 from interfering with other adjacent members even when attached to a camshaft or the like. Here, the thickness of the annular plate 11 (the depth of the holding portion 9a) is appropriately set according to the degree of vibration required for the main body 2 and is a thickness that can attenuate the vibration of the main body 2. For example, the thickness of the main body 2 (the thickness of the rim 12 and the annular protrusion 8) is 0.2 to 0.5 times, preferably about 0.3 to 0.4 times. ing.

  The annular groove 9 is formed wider than the annular plate 11, and when the annular plate 11 is disposed, a recess 9 b is formed on the outer periphery of the annular plate 11. The annular groove portion 9 is designed to be light in weight by mounting the annular plate 11 so that the concave portion 9b faces. A material having a second natural frequency different from the first natural frequency of the main body 2 is selected for the annular plate 11. Here, the natural frequency is lower than the first natural frequency and the vibration damping effect is high. Ductile cast iron (FCD (Ferrum Casting Ductile)) and hot rolled steel plate (SPH) are used. When a hot-rolled steel plate is used, the annular plate 11 can be easily formed by pressing.

  The annular plate 11 is press-fitted into the outer periphery of the annular protrusion 8, that is, the inner peripheral surface of the annular groove 9, so that the inner peripheral surface is held on the outer peripheral surface of the annular protrusion 8 by an interference fit. Although the annular plate 11 is in contact with the bottom surface of the annular groove portion 9 and is not bonded, it is free. As a result, the annular plate 11 does not vibrate integrally with the main body 2, but vibrates at a unique frequency separately from the main body 2, and can attenuate the vibration of the main body 2. The annular plate 11 may be attached to the annular protrusion 8 by welding, an adhesive, or the like instead of press fitting.

  A projecting annular portion 10 is further provided on the outer peripheral side of the second central recess 7 on the other surface of the main body 2, and an annular recess 10 a is formed on the outer peripheral side of the annular portion 10. The main body 2 is designed to reduce the overall weight by forming an annular recess 10a on the other surface.

According to the low noise gear 1 of the first embodiment, the effects listed below can be obtained.
(1) The low noise gear 1 is rotationally driven when opening and closing an engine valve. The low-noise gear 1 that is a cam gear receives the biasing force of a spring that biases the intake / exhaust valve in the closing direction in the rotational direction. Therefore, when the valve is rotated to open and close, torque fluctuation occurs, and the meshed gear Noise is generated between them. Specifically, the main body 2 vibrates the entire surface due to torque fluctuation, backlash, etc., and generates noise. The main body 2 uses a high-hardness material such as S53C (mechanical structural carbon steel), chrome steel, or chrome molybdenum steel, so that the required physical strength can be secured, but the attenuation with respect to sound is small.

  In the low noise gear 1, an annular plate 11 having a natural frequency different from that of the main body portion 2 is press-fitted into the annular protrusion 8 in the annular groove portion 9. Vibrate. Therefore, the annular plate 11 can be damped so as to suppress vibration generated in the entire main body 2. Thereby, the low noise gear 1 can reduce the noise which arises by a torque fluctuation etc. in a short time. Furthermore, the excitation force from the low noise gear 1 which is a cam gear to the peripheral parts can be reduced.

  (2) In addition, since the low noise gear 1 uses a high hardness material for the advanced parts and the main body 2, it is possible to maintain the physical strength while reducing the noise as described above. it can.

  (3) Furthermore, the annular plate 11 can be easily attached to the annular groove portion 9 by press fitting, and the configuration of the low noise gear 1 into which the annular plate 11 is press fitted can be simplified.

(Second Embodiment)
As shown in FIG. 4, the annular plate 11 may be an arcuate plate 21 in which a ring is divided into a plurality of parts. In the example shown in FIG. 4, a plurality of radial protrusions 22 are formed in the annular groove 9 at regular intervals radially from the outer periphery of the annular protrusion 8. An arcuate plate 21 serving as a vibration isolating plate is disposed between the radial protrusions 22 and 22. The arc-shaped plate 21 has an outer peripheral portion of the annular protrusion 8 and a side edge of the radial protrusion 22 as a holding portion, and is attached to the holding portion by press-fitting, welding, an adhesive, or the like. In the case of press-fitting, the arc-shaped plate 21 is tightly fitted in a region surrounded by the outer periphery of the annular protrusion 8 and the radial protrusions 22 and 22 in three directions.

  The radial protrusions 22 may be formed across the outer periphery of the annular protrusion 8 and the rim 12. The radial protrusions 22 may be formed at irregular intervals in the circumferential direction. Furthermore, the number which divides | segments the annular groove part 9 by the radial protrusion 22 is not specifically limited, Two, three, or more may be sufficient.

(Third embodiment)
The annular plate 11 is press-fitted into the outer periphery of the annular protrusion 8 and its inner peripheral surface is not held by the outer peripheral surface of the annular protrusion 8, but as shown in FIG. Also good. For example, the outer diameter of the annular plate 11 is substantially matched with the inner diameter of the rim 12. Then, the inside of the rim 12 is used as a holding portion 9a, the annular plate 11 is press-fitted into the holding portion 9a, and the outer peripheral surface thereof is pressed against the inner peripheral surface of the rim 12, and is held with an interference fit. Even with such a configuration, the same effects as the above (1) to (3) can be obtained. In this case, a recess 9 b is formed between the annular plate 11 and the annular protrusion 8.

(Fourth embodiment)
As described above, the holding portion 9a in the annular groove portion 9 in which the annular plate 11 is disposed may be formed as a recess with respect to the main surface of the main body portion 2, and as shown in FIG. 27 may be used. The annular ribs 26 and 27 are formed so as to be separated from each other in accordance with the width of the annular plate 11, and the space between the annular ribs 26 and 27 is a holding portion 9 a. The annular plate 11 is press-fitted between the annular ribs 26 and 27. In the annular plate 11, the inner peripheral surface and the outer peripheral surface are held on the annular ribs 26 and 27 by interference fit, and are free from the bottom surface of the annular groove portion 9 formed by the annular ribs 26 and 27. Accordingly, the annular plate 11 can be damped so as to vibrate at a specific frequency separately from the main body 2 and suppress the vibration of the main body 2. Thereby, the low noise gear 1 can reduce the noise caused by the torque fluctuation or the like.

  As shown in FIG. 7, the annular rib may be only the annular rib 26 on the outer peripheral side, and the configuration may be simplified as compared with FIG. 6. In this case, the annular plate 11 is press-fitted inside the annular rib 26, the outer peripheral surface of the annular plate 11 is pressed against the annular rib 26, and is held on the annular rib 26 by an interference fit.

  Further, as shown in FIG. 8, the annular rib may be only the annular rib 27 on the inner peripheral side, and the configuration may be simplified as compared with FIG. 6. In this case, the annular plate 11 is press-fitted outside the annular rib 27, the inner peripheral surface of the annular plate 11 is pressed against the annular rib 27, and is held on the annular rib 27 by an interference fit.

In addition, you may change the said 1st-4th embodiment as follows.
In the above example, the cam gear has been described as an example. However, the gear to which the present invention is applied is also provided in the engine and the engine periphery such as a power steering pump driving gear, an air compressor driving gear, and an oil pump driving gear. The present invention can also be applied to a disposed engine gear. Furthermore, the gear of the present invention can also be applied to general gears that generate torque fluctuations.
The material of the annular plate 11 and the arc-shaped plate 21 is not limited to ductile cast iron (FCD (Ferrum Casting Ductile)) or hot rolled steel plate (SPH) as long as the natural frequency is different from that of the main body 2. For example, a synthetic resin plate or the like may be used.

The annular plate 11 and the arcuate plate 21 may be provided on the other surface of the main body 2 or may be provided on both surfaces of the main body 2.
As the type of gear, in addition to a spur gear, a helical gear, a helical gear, or the like may be used.

  DESCRIPTION OF SYMBOLS 1 ... Low noise gear, 2 ... Main-body part, 3 ... Gear part, 4 ... Center hole, 5 ... 1st center recessed part, 6 ... Engagement part, 6a ... Knock pin, 7 ... 2nd center recessed part, 8 ... Annular protrusion , 9 ... annular groove, 9a ... holding part, 9b ... recess, 10 ... annular part, 10a ... annular recess, 11 ... annular plate, 12 ... rim, 21 ... arc plate, 22 ... radial projection, 26 ... annular rib , 27 ... annular ribs.

Claims (5)

A main body having a disk shape and provided with a gear on the outer periphery;
A vibration isolating plate having a natural frequency different from that of the main body;
A holding part that is provided in the main body part and holds a side surface of the vibration isolation plate;
Equipped with a,
The main body has an annular groove concentric with the main body on one surface of the main body,
The annular groove portion is composed of the holding portion and an annular recess located outside the holding portion in the radial direction of the main body portion,
The depth of the concave portion is deeper than the depth of the holding portion with respect to one surface of the main body portion.
Low noise gear. The anti-vibration plate, the side surface of the annular groove, is held by press fit, low noise gear according to claim 1, wherein the free to the bottom surface of the annular groove. The low noise gear according to claim 1 or 2, wherein the vibration isolation plate is annular. The main body is one of high carbon steel, chrome steel, chrome molybdenum steel,
The low-noise gear according to claim 1, wherein the vibration-proof plate is ductile cast iron. The main body is one of high carbon steel, chrome steel, chrome molybdenum steel,
The low-noise gear according to claim 1, wherein the vibration-proof plate is a hot-rolled steel plate.

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