JPS61282664A - Backlash reducing apparatus for gear transmission system - Google Patents

Abstract

PURPOSE:To reduce the backlash between gears by concentrically arranging a subgear which can revolve relatively to a main gear on a rotary shaft and arranging a turning apparatus using a weight which relatively turns the both gears by the centrifugal force, between the both gears. CONSTITUTION:A main gear 17 having a boss part is installed onto a rotary shaft 16, and a subgear 18 which can be revolved relatively to the main gear 17 is installed onto the boss of the main gear 17. The weight guiding grooves 19 and 20 in which the axis lines in the longitudinal direction cross each other are formed onto the opposed surfaces of the both gears 17 and 18, and a weight 21 engaged with the both grooves 19 and 20 is arranged in the crossing part. Therefore, when the rotary shaft 16 is revolved, the weight 21 is shifted in the radial direction by the centrifugal force, and the both gears are relatively revolved through the guide grooves 19 and 20, and the backlash between the opponent gear can be reduced.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a backlash reduction device applied to a gear transmission system such as a valve train camshaft drive device that transmits the power of an internal combustion engine to a camshaft via a gear train. (Prior art and its problems) In general, there is torque fluctuation in a gear transmission system such as a valve train camshaft drive device of an internal combustion engine as described above, and backlash caused by the torque fluctuation rapidly causes impact trapping. This causes problems such as increased hammering noise and damage to gears due to abnormal loads due to transmission system resonance. In order to solve this problem, conventionally, one of the driving and driven gears that mesh with each other is connected to a main gear that is integrally rotatably supported on a rotating shaft, and a main gear that is coaxial with the main gear. A secondary gear is supported so as to be relatively rotatable, and a spring is interposed between the main gear and the secondary gear to bias both gears in a relative direction, so that the biasing force of the spring allows the main gear to It is known that a counter gear is sandwiched (meshed) at a position where the tooth portions of the auxiliary gear are relatively shifted, thereby reducing backlash and absorbing impact force. If the spring force of the conventional type is weak, the backlash reduction effect will be lost when the rotation speed is high.If the spring force is strengthened to prevent this, meshing noise will be generated when the rotation speed is low. Therefore, backlash can be reliably reduced over the entire range from low to high rotation speeds for gear transmission systems where torque fluctuation differences vary significantly, such as those used in internal combustion engines. (Objective of the Invention) The present invention has been made in view of the above circumstances, and is intended to be applied to gear transmission systems where the difference in torque fluctuation changes significantly from a low rotation range to a high rotation range. The purpose of the present invention is to provide a backlash reduction device for a gear transmission system that can reliably reduce backlash over the entire area. (Means for solving the problem) In order to solve the above-mentioned problem. The present invention provides a main gear in which the gear of a gear transmission system having a driving gear and a driven gear that mesh with each other is integrally rotatably supported on a rotating shaft;
The main gear and the sub gear are coaxially supported so as to be relatively rotatable, and the main gear and the sub gear are rotated relative to each other according to the centrifugal force accompanying the rotation. Means is provided for reducing the interference between the drive side gear and the driven side gear. (Example) Hereinafter, one example of the present invention will be described based on the drawings. 1st
The figure is a side view of a valve train camshaft drive device for a type multi-cylinder engine equipped with the backlash reduction device of the present invention.
．． 1° is a piston fitted in a cylinder 2.2', and these pistons 1.1' are connected to the crankshaft 4 via conlofts 3, 3', and as the pistons 1, 1° reciprocate, the crankshaft 4 is rotated. The rotation of the crankshaft 4 is caused by a crank gear 5, an input idle gear 6 that meshes with the crank gear 5, an output idle gear 7 that rotates coaxially with the input idle gear 6, and an intermediate gear that meshes with the output idle gear 7. Idle gears 8.8', final idle gears 9.9" meshing with these intermediate idle gears 8.8", and cam gears to, ti. 10', 11 meshing with these final idle gears 9.9g. ” to the camshafts 14.14° and 15.15° of the intake valves 12.12″ of each cylinder 2°2′ and the exhaust valves 13.13°, respectively. The backlash reduction device of the present invention can be applied to any gears that mesh with each other in a camshaft drive device, but in this embodiment, the backlash reduction device of the present invention is applied to the output side idle gear 7 and one of the intermediate idle gears. 8. That is, as shown in FIGS. 2 and 3, the output side idle gear 7, which is the drive side, has a main gear 17 integrally rotatably supported on its rotation shaft 16, It is composed of the main gear 17 and a sub gear 18 supported on the same shaft 16 so as to be relatively rotatable. A plurality of (for example, four) elongated grooves 19 are formed at equal intervals in the circumferential direction on the surface of the main gear 17 facing the auxiliary gear 18. The grooves 19 are arranged such that their long axes l are all inclined in the same direction by an angle θ with respect to an axis passing through the center 0 of the groove 19 and the center 01 of the main gear 17. 17 grooves 19, the same number of grooves 20 as the grooves 19 are formed on the surface of the secondary gear 18 facing the main gear 17, equally spaced in the circumferential direction.The grooves 20 of these secondary gears 18 are It has the same shape and size as the groove 19 of the main gear 17, and its center 02
The groove 19 also coincides with the center O of the groove 19. Further, the long axis 11 of the groove 20 of the secondary gear 18 is all in the same direction with respect to the axis L1 passing through the center 02 of the groove 20 and the center 03 of the secondary gear 18, and the same angle θ as the groove 19 of the main gear 17. However, the grooves 19 and 20 are inclined in opposite directions. Are the main gear 17 and the secondary gear 18 facing each other? a1
A weight 21 is slidably fitted between 9 and 20, respectively. The weight 21 has a circular cross-section (or may be spherical, etc.), and moves toward the outer periphery due to the action of centrifugal force accompanying the rotation of both gears 17.1.
8 is relatively rotated, and a serasica is applied according to the rotational speed. (Function) Next, the function of the backlash reduction device for a gear transmission system of the present invention having the above configuration will be explained. The rotational power of the main gear 17 and the auxiliary gear 18 of the output side idle gear 7, which are drive side gears, is as follows.
Intermediate a is the driven gear. The signal is transmitted to the idle gear 8 via the meshing point K between the intermediate idle gear 8 and the main gear 17;
Let us consider the case where backlash exists at the meshing point K between the intermediate idle gear 8 and the intermediate idle gear 8. As the gears 17, 18, and 8 rotate, the weight 21 moves in the radial direction (direction of arrow OP in Fig. 2).
A centrifugal force is generated, and the weight 21 moves along the grooves 19.20 of both gears 17.18 in the direction of the arrow OP. As a result, the arrow O in FIG. 2, which is one component force of the arrow OP, is
The main gear 17 is rotated counterclockwise in FIG. 2 by R, and the secondary gear 18 is rotated clockwise in FIG. 2 by the other component of force, indicated by the arrow OR in FIG. 2. That is, the main gear 17 and the auxiliary gear 18 rotate relative to each other, and the amount of rotation is determined by the weight 21.
The centrifugal force of the beating is proportional to the rotation speed of the main gear 17 and the secondary gear 18, and when the rotation speed is low, the relative rotation amount of the main gear 17 and the secondary gear 18 is small according to the rotation, and accordingly, If the rotation speed increases, the relative rotation amount of the main gear 17 and the auxiliary gear 18 will increase in accordance with the rotation, and the selastica will also become larger. Therefore, there is no hitting sound even in the high speed range and the impact load can be reduced, and no meshing noise is generated even in the low speed range. Note that due to the decrease in centrifugal force as the rotational speed changes from a high state to a low state, the weight 21 moves along the -line and Li along the groove 19.20 to the center of the main gear 17 and the auxiliary gear 18. When the weight 21 moves to the side, a wedge action occurs due to the fact that both widthwise edges of the grooves 19 and 20 are inclined at an angle of θ with respect to the axis Li, which prevents the weight 21 from returning. Since a resistance force is generated and the main gear 17 and the auxiliary gear 18 gradually rotate back, the serasica does not decrease rapidly. In the above embodiments, the case where the backlash reduction device of the present invention is applied to a valve train camshaft drive device of an internal combustion engine has been described, but the present invention is not limited to this, and the backlash reduction device of the present invention is not limited to this, but can be applied to a drive side gear and a driven side gear that mesh with each other. The present invention is applicable to any gear transmission system as long as it has gears. Also, there is a means for reducing backlash between the driving gear and the driven gear by rotating the main gear and the secondary gear relative to each other in response to the centrifugal force accompanying the rotation. Although the grooves 19 and 20 and the weight 21 are used, the present invention is not limited thereto. (Effects of the Invention) As detailed above, the backlash reduction device for a gear transmission system of the present invention integrates the gears of a gear transmission system having a driving side gear and a driven side gear that mesh with each other onto a rotating shaft. It is composed of a main gear that is rotatably supported, and a sub gear that is coaxially supported with the main gear so that it can rotate relative to the main gear. The present invention is characterized by being provided with a means for rotating both gears relatively to reduce backlash between the drive side gear and the driven side gear.Therefore, the difference in torque fluctuation is significantly reduced. For gear transmission systems that change, it is possible to reliably reduce backlash over the entire range from low rotation range to high rotation range, and it is possible to reduce impact loads without producing knocking noise even in high rotation range. It has the effect of not producing meshing noise even in the low rotation range.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a valve train camshaft drive device for a V-type multi-cylinder engine equipped with the backlash reduction device of the present invention, and FIG. 2 is an enlarged view of the main parts. The side view, FIG. 3, is a sectional view taken along line mm in FIG. 2. 7... Output side idle gear (drive side gear), 8...
Intermediate idle gear (driven gear), 16... Rotating shaft, 17... Main gear, 18... Secondary gear, 19.20.
... Groove, 21... Weight. Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshi Watanabe Onma Nagato Kanji Illustration 2 Procedural Amendment (self-imposed November 20, 1985 Director General of the Patent Office Michibe Uga 1, Indication of the case 1985) Patent Application No. 125519 2゜3, Relationship with the person making the amendment Patent applicant address 2-1-1 Minami-Aoyama, Minato-ku, Tokyo Name (532)
) Kore Kume, Representative of Honda Motor Co., Ltd.
4. Agent address: Sasaya Ito Building, 5-10-8 Shinbashi, Minato-ku, Tokyo Subject to 56 amendments
3゜(1) Full text of the specification Title of the invention Backlash reduction device for gear transmission system Claims: At least one of the aforementioned gear transmission systems having a driving side gear and a driven side gear meshing with each other. The gear is composed of a main gear that is integrally rotatably supported on a rotating shaft, and a auxiliary gear that is coaxially supported with the main gear so that it can rotate relative to the main gear, and a rotational gear is provided between the main gear and the auxiliary gear. A back of a gear transmission system, characterized in that it is provided with means for reducing backlash between the drive side gear and the driven side gear by relatively rotating both gears in response to accompanying centrifugal force. Lash reduction device. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a backlash control system commonly used in a gear transmission system such as a valve camshaft drive device that transmits the power of an internal combustion engine to a camshaft via a gear train. Relating to a reduction device. (Prior art and its problems) In general, there is torque fluctuation in a gear transmission system such as a valve train camshaft drive device of an internal combustion engine as described above, and backlash due to the torque fluctuation rapidly increases the impact load and causes impact. This causes problems such as increased noise and damage to gears due to abnormal loads due to transmission system resonance. In order to solve this problem, conventionally, one of the driving and driven gears that mesh with each other is connected to a main gear that is integrally rotatably supported on a rotating shaft, and a main gear that is coaxial with the main gear. A secondary gear is supported so as to be relatively rotatable, and a spring is interposed between the main gear and the secondary gear to bias both gears in a relative direction, so that the biasing force of the spring allows the main gear to It is known that a counter gear is meshed with the gear in a state where the tooth portions of the auxiliary gear are relatively shifted, thereby reducing backlash and absorbing impact force. In such conventional devices, if the spring force is weak against torque fluctuations, the backlash reduction effect is lost, and if the spring force is strengthened to prevent this, meshing noise is generated. Therefore, it is difficult to reliably reduce backlash over the entire range from low to high speeds in gear transmission systems where torque fluctuations vary significantly, such as those used in internal combustion engines. there were. (Object of the Invention) The present invention has been made in view of the above circumstances, and is intended to reduce meshing noise caused by backlash over the entire range from low rotation to high rotation for gear transmission systems where torque fluctuations vary significantly. It is an object of the present invention to provide a backlash reduction device for a gear transmission system that can reliably reduce . (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a gear transmission system having a drive side gear and a driven side gear that mesh with each other. , consists of a main gear that is integrally rotatably supported on a rotating shaft, and a sub gear that is coaxially supported with the main gear so that it can rotate relative to the main gear, and a centrifugal gear that is connected to the main gear and the sub gear due to rotation. A means is provided to reduce backlash between the driving gear and the driven gear by relatively rotating both gears according to the force. (Operation) The rotation of the main gear and the secondary gear The backlash between the drive side gear and the driven side gear is reduced by relatively rotating both gears by the backlash reduction means in accordance with the centrifugal force accompanying the rotation. (Example) Below, the backlash is reduced. An embodiment of the present invention will be explained based on the drawings.
The figure is a side view of a valve train camshaft drive device for a V-type multi-cylinder engine equipped with the backlash reduction device of the present invention.
, 1° are pistons fitted in the cylinders 2 and 2', and these pistons 1.1' are connected to the crankshaft 4 via a connecting rod 3.3', and as the pistons 1.1" reciprocate, the crankshaft The shaft 4 is rotated.The rotation of the crankshaft 4 is caused by a crank gear 5, a driven idle gear 6 that meshes with the crank gear 5, a driving idle gear 7 that rotates coaxially with the driven idle gear 6, and a driven idle gear 7 that rotates coaxially with the driven idle gear 6. Drive side idle gear 7
a driven idle gear 8.8'' that meshes with the driven idle gears 8, 89, a final idle gear 9.9'' that meshes with these driven idle gears 8, 89, and a cam gear that meshes with these final idle gears 9.9'. 10, 11.10'', 11' respectively to the intake valve 12.12' of each cylinder 2.21 and the respective camshaft 14.14' and 15.13' of the exhaust valve 13.13'.
15° respectively. The backlash reduction device of the present invention can be applied to any gears that mesh with each other in such a valve camshaft drive device, but in this embodiment, the backlash reduction device of the present invention In other words, as shown in FIGS. 2 and 3, the driving idle gear 7 is supported on its rotating shaft 16 so as to be integrally rotatable. It is composed of a main gear 17 and a sub gear 18 that is supported relatively rotatably on the rotating shaft 16, and these main gear 17 and sub gear 18 are in a state where their opposing surfaces are in sliding contact with each other, It meshes with the drive side idle gear 8.8". A plurality (for example, four) of elongated grooves 19 are formed on the surface of the main gear 17 that faces the auxiliary gear 18 and are equally spaced in the circumferential direction. These grooves 19 have their long axes l at a certain point M on the axis passing through the center O of the grooves 19 and the center 01 of the main gear 17.
All angles θ1 are made in the same direction with respect to the axis with reference to
It is placed at an angle. Corresponding to the grooves 19 of the main gear 17, the same number of grooves 20 as the grooves 19 are formed on the surface of the auxiliary gear 18 facing the main gear 17 and equally spaced in the circumferential direction. The grooves 20 of these auxiliary gears 18 have the same shape and size as the grooves 19 of the main gear 17, and their centers 02 also coincide with the centers 0 of the grooves 19. Further, the long axis lines 11 of the grooves 20 of the secondary gear 18 are all directed in the same direction with respect to the axis L1, with a certain point M on the axis L1 passing through the center o2 of the groove 20 and the center o3 of the secondary gear 18 as a reference. Although the grooves 19 and 20 are inclined by the same angle θ2 as the grooves 19 of the main gear 17, the grooves 19 and 20 are inclined in opposite directions. The side surface in the width direction of one groove 19 is one clamping surface A, and the side surface in the width direction of the other groove 20 is the other clamping surface B. Note that the left and right angles θ1 and θ2 are not limited to θ1 = θ2, but θ1 #θ2 or θ1 ≠ θ2
But that's fine. Grooves 19 facing each other in these main gears 17 and auxiliary gears 18
A weight 21 is slidably fitted between and 20, respectively. The weight 21 has a circular cross-section (it may be spherical or piece-shaped), and moves toward the outer circumference due to the action of centrifugal force accompanying the rotation of both gears 17 and 18. .18 is rotated relatively, and a serasica is given according to the rotation speed. Next, the operation of the backlash reduction device for a gear transmission system of the present invention having the above configuration will be explained based on FIG. 4. The rotational power of the main gear 17 and the auxiliary gear 18 of the drive side idle gear 7 is
It is transmitted to the driven side idle gear 8°8° through the meshing point K between the driven side idle gear 8.89 and the main gear 17.
．． Consider the case where backlash exists at the engagement point K between 8 degrees. Each of the gears 17 and 18 vibrates between the teeth of the pair of gears of the idle gears 8 and 8 degrees on the driven side due to torque fluctuations as the gears rotate. As a result, each clamping surface A
, H will be repeatedly expanded and contracted, and at the time of expansion, the weight 21 is sandwiched between the clamping surfaces A and B by the centrifugal force generated by the rotation of the rotating shaft 16. . That is, the centrifugal force is mainly used to move the weight 21 in a direction that minimizes backlash. Furthermore, the weight 21 sandwiched between the two clamping surfaces A and B
Frictional force between the weight 21 and both clamping surfaces A and B caused by the force P that is ejected in the axial direction according to the angle (clamping angle) θ (= θ1 + θ2) formed by the gear and the force N that acts in the circumferential direction of the gear. F
(= μN, where μ is the coefficient of friction), the weight 21 is held in a substantially fixed position. Further, as the rotation speed shifts to a high speed range, the centrifugal force on the weight 21 increases, and this centrifugal force further resists the force P and exerts a force to hold the weight 21 between the gripping surfaces A and B. Since the torque is increased, the backlash is balanced against the torque fluctuation at the minimum position, and meshing noise caused by backlash can be reduced over the entire range from low rotation to high rotation. What is important here is that the balance condition of the weight 21 is that both clamping surfaces A,
This is a function only of the clamping angle θ between B and the friction coefficient μ of the contact portion of the weight 21, and is not related to the strong force N received from the tooth surface. Therefore, the friction coefficient μ is set so that the force P becomes approximately zero.
By setting the clamping angle θ to , it is possible to receive a large torque transmission force and an impact load due to backlash with a small force generated by centrifugal force other than the above-mentioned balance condition. In addition, since centrifugal force is generated in proportion to the square of the rotational speed, if the clamping angle θ and friction coefficient μ are set so as to satisfy the equilibrium condition near engine idling, then the higher the rotational speed is Backlash can be reduced with large force. Conversely, when the thermal expansion of the internal combustion engine case acts in the direction of contraction after load operation, the backlash on the tooth surface decreases and the weight tends to return to its original state. In this case, it is assumed that the engine is in a stopped state after a long period of idling,
In other words, the centrifugal force is small, the tooth moves easily reversibly, and no lash is maintained at an appropriate load without generating an excessive tooth surface load. This effect is not due to centrifugal force, but may be caused by other forces such as spring force, hydraulic pressure, shape memory alloy, etc., as long as the above-mentioned balance conditions are satisfied, and if the clamping angle θ is reversed, the direction opposite to centrifugal force can be exerted. It holds even if force is applied to . In particular, when sufficient centrifugal force cannot be obtained, such as when the rotational speed is low, other forces such as spring force, hydraulic pressure, magnetic force, etc. can be substituted. Note that due to the decrease in centrifugal force as the rotational speed changes from a high state to a low state, the weight 21 moves in the groove 19.2Q toward the center of the main gear 17 and the secondary gear 18 along the axis Lt. At this time, both edges of the groove 19°20 in the width direction are at an angle of θ1. with respect to the axis L+. Due to the inclination at an angle of θ2, a wedge action occurs and a resistance force is generated against the movement of the weight 21 toward the center, and the main gear 17 and the secondary gear 18 gradually return to rotation, so that the selastica rapidly rotates. It never decreases. In addition, in the above embodiment, the case where the backlash reduction device of the present invention is applied to a valve train camshaft drive device of an internal combustion engine has been described, but the invention is not limited to this, and the backlash reduction device of the present invention is not limited to this, but can be applied to a drive side gear and a driven side gear that mesh with each other. The present invention is applicable to any gear transmission system as long as it has gears. Further, a means is provided between the main gear and the auxiliary gear to reduce backlash between the drive side gear and the driven side gear by relatively rotating both gears in accordance with the centrifugal force accompanying the rotation. Although it is constructed by the grooves 19 and 20 and the weight 21, it is not limited thereto. (Effects of the Invention) As detailed above, the backlash reduction device for a gear transmission system of the present invention provides at least one gear of a gear transmission system having a driving gear and a driven gear that mesh with each other.
Consisting of a main gear that is integrally rotatably supported on a rotating shaft, and a sub gear that is coaxially supported with the main gear so that it can rotate relative to the main gear, centrifugal force due to rotation is generated between the main gear and the sub gear. The present invention is characterized in that a means is provided for reducing backlash between the drive side gear and the driven side gear by rotating both gears relative to each other in accordance with the above. Therefore, for gear transmission systems in which torque fluctuations vary significantly, backlash can be reliably reduced over the entire range from low rotation to high rotation, and impact loads can be reduced without producing hammering noise. It has the effect of not producing meshing noise even in the entire rotation range.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show one embodiment of the present invention, and FIG. The figure is an enlarged side view of the main part, FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. 2, and FIG. 4 is an explanatory diagram of the operation. 7... Drive side idle gear (drive side gear), 8° 8°
... Driven side idle gear (driven side gear), 16.
... Rotating shaft, 17... Main gear, 18... Secondary gear, 1
9.20... Groove, 21... Weight. *2 seagull

Claims (1)

[Claims] 1. The gear of a gear transmission system having a driving gear and a driven gear that mesh with each other is connected to a main gear that is integrally rotatably supported on a rotating shaft, and a main gear that is supported coaxially with the main gear so as to be relatively rotatable. The main gear and the auxiliary gear are configured to rotate relative to each other according to the centrifugal force accompanying rotation between the main gear and the auxiliary gear, thereby creating a gap between the drive side gear and the driven side gear. 1. A backlash reduction device for a gear transmission system, comprising a means for reducing backlash.