JPH08135767A - Gear device - Google Patents

Abstract

PURPOSE: To provide a backlash eliminating function and reduce frictional noise under mesh generated when the rotational speed of a gear is increased. CONSTITUTION: In a gear device in which a main gear 2 and a backlash eliminating gear 3 with the same number of gear teeth are positioned coaxially, a pressing body 6 is installed on one of the gears 2 and 3 movably in radial direction, and also an elastic body which applies a radial inward force to the pressing body 6 is installed additionally to it. Also a body to be pressed 7 which is made in contact with the pressing body 6 and exerts a contact force including radial outward and circumferential components is fixed to the other gear. Then a slight phase difference is given between both gears 2 and 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear device having a backlash removing function.

[0002]

2. Description of the Related Art The backlash of a gear is a gap between a pair of teeth that mesh with each other. The backlash of a gear is originally prevented from being rubbed due to a tooth profile error and an assembly error, and the teeth are smoothly meshed. It is provided for the purpose of doing.
However, the above-mentioned gear backlash has inconveniences such as generation of rattling noise at a portion where the gears mesh. In particular,
When power is transmitted from a gear fixed to the crankshaft of a four-stroke engine or the like to another clutch gear or the like, the torque for driving the crankshaft varies depending on whether the accelerator is turned on or off. Due to a torque fluctuation such as a noticeable fluctuation in the torque transmitted in each of the strokes, the gear transmitting the torque is switched between the two gears, and rattling noise is generated between the meshing gears. For this reason, there is a demand for a gear device for eliminating backlash that can prevent the generation of rattling noise while making use of the advantages of the backlash described above, that is, the prevention of friction on the back surface of the teeth and the smooth engagement of the teeth.

Conventionally, there are the following devices for removing gear backlash as described above.

(A) A structure in which a main gear fixed to a shaft for transmitting power and a backlash removing gear having the same tooth tip circle, root circle and pitch circle and a large number of teeth are coaxially superposed. There is a gear device. Since the two gears have different numbers of teeth, they have different rotational speeds. As a result, a frictional force generated on a side surface where the two gears come into contact causes a repulsive force between the two gears in the rotational direction (hereinafter referred to as a rotational repulsive force). Is given. The backlash is eliminated by the rotational repulsion and the circumferential pitch difference caused by the difference in the number of teeth of both gears.

(B) As shown in FIGS. 5 and 6, a main gear 21 fixed to a shaft 20 for transmitting power
A plurality of recesses 22 are formed on the side surface of the main gear 21 in the circumferential direction. A compression coil spring 23 is accommodated in the recess 22 so as to be able to expand and contract at right angles to the radial direction. Backlash removal gear 24
There is a gear device having a structure in which a reaction force receiver 25 protruding from the gear is inserted into the concave portion 22 so as to compress the compression coil spring 23, and the gears 21 and 24 are fixed by rivets 26 so as to be rotatable by a small angle. . With such a structure, a rotational repulsion force and a phase difference are applied between the two gears 21 and 24 to eliminate backlash. As a technique similar to this example, there is Japanese Utility Model Laid-Open No. 59-196763. In the structure of this embodiment, the compression coil spring is replaced by an elastic block made of rubber or the like.
There is No. 6.

[0006]

The conventional technique introduced above has the following disadvantages.

(1) In the gear device shown in (A) of the above-mentioned prior art, the rattling noise is eliminated at the portion where the gears mesh, but it is generated when the rear surfaces of the gears mesh with the increase in the rotation speed of the gear. Fricative noise tends to be promoted. In the case of this prior art, a rotational repulsion force is generated between the two gears due to the frictional force generated on the side surface where the two gears come into contact.Since the kinetic frictional force is independent of the slip speed, even if the gear rotation speed increases, The rotation repulsion is constant. This repulsive force is
Since it has the effect of pinching the teeth of the mating gears that mesh with each other, the rotational speed of the gears increases under a constant rotational repulsion force, and as the meshing speed of both gears increases, the frictional noise generated at that time increases. From this point of view, the above inconvenience occurs.

(2) Even in the gear device shown in (B) of the prior art (see FIGS. 5 and 6), gear rattling noise disappears at the gear meshing portion, as in the case of (A), but the gear device As the number of rotations increases, the friction noise generated when the back surfaces of the gears mesh with each other tends to be promoted. In the case of this prior art, the rotation repulsion is generated by the reaction force of the compression coil spring, but the reaction force of the compression coil spring is independent of the rotation speed of the gear and is constant even when the rotation speed increases. Therefore, as in the case of the above (A), when the rotation speed of the gears increases and the speed at which the two gears mesh with each other increases, the friction noise generated at that time increases.

The present invention has been made to solve the above-mentioned conventional inconvenience. In the gear device, the backlash is removed in order to prevent the generation of gear rattling noise, and the gear device is generated as the number of rotations of the gear increases. The purpose is to reduce the frictional noise during meshing.

[0010]

In order to achieve the above object, the gear device of the present invention comprises: (1) a main gear for transmitting power, and a backlash removing gear that is coaxially overlapped with the main gear. The gears are provided so as to be relatively rotatable in a minute angle range including a state where the phases of both gears match each other, and the repulsive force of the backlash removing gear and the main gear (as described above, means the force repulsive in the rotational direction). The same shall apply hereinafter), and the phase of the backlash removing gear is shifted in the direction in which the rotational repulsive force acts so that the backlash can be removed, and stopped. A movable body is attached to the movable body, and an elastic body that applies a force inward in the radial direction is attached to the movable body, and the other gear is in contact with the movable body and radially outward and circumferentially. The object to be pressed is fixed, which exerts a contact force including a component force in the direction on the object to be pressed.

(2) As described in claim 2, in the gear device according to claim 1, the one gear provided with the pressing body and the elastic body is the backlash removing gear, and the pressed body is fixed. The other gear is the main gear, the elastic body is one or more compressed springs housed in the tooth width of the backlash removing gear in the radial direction, and the pressing body is one of the springs. Attached to one end near the axis of the gear, and its pressing surface is inclined in a certain direction with respect to a surface perpendicular to the radial direction while keeping the pressing surface parallel to the axis of the gear. Can be abutted against the pressing surface of the pressing body housed in the backlash removing gear.

(3) As described in claim 3, another backlash removing gear is coaxially superimposed on the gear device according to claim 2, and the backlash removing gear is the other backlash removing gear. While having the same configuration as the gear, the direction of the inclination of the pressing surface is reversed, and on the side of the main gear, a pressed body is protruded toward the backlash removing gear, and the pressing body in the backlash removing gear is provided. It is good to contact with the pressing surface of.

[0013]

According to the gear device of the present invention having the above-described configuration, the following operations are provided.

(1) The circumferential component force generated by the contact between the pressing body and the pressed body becomes a rotational repulsive force acting between the main gear and the backlash removing gear. The rotational repulsion, the phase difference, and the backlash elimination gear applied to the main gear can be rotated by a small angle in both the forward and reverse directions while resisting the rotational repulsion against the main gear. When the power is transmitted to another gear by rotating the gear device in the acting direction, and when the power is transmitted from the other gear by rotating the gear device in the direction opposite to the direction in which the rotational repulsive force acts on the main gear. ,
A backlash removing gear is applied to the backlash generated at the time of meshing, and the backlash can be removed. However, when the transmitted torque is smaller than the rotational repulsion acting between the two gears, the backlash can be eliminated not only in the case described above.

Further, since the pressing body has a predetermined mass,
As the rotational speed of the gear increases, the centrifugal force acting on the pressing body increases. The centrifugal force, which is the outward force in the radial direction, and the reaction force of the elastic body, which is the inward force in the radial direction, cancel each other, and the inward force in the radial direction is reduced. The force in the circumferential direction, which is the force, also decreases as the rotational speed increases. Therefore, the rotational repulsive force acting between both gears becomes smaller as the number of rotations increases. As a result, the friction noise at the time of meshing in the high rotation range is reduced.

(2) According to the gear device of the second aspect,
The pressing body presses the pressed body in the center direction by the reaction force of the spring, but the pressing surface (the surface of the pressing body that comes into contact with the pressed body) is kept in parallel with the gear axis in the radial direction. Since the pressing body is inclined with respect to the vertical surface, a part of the force of the pressing body pressing the pressed body in the center direction is converted into the force of pressing the pressed body in the circumferential direction. As a result, a rotational repulsive force can be generated in the main gear and the backlash removing gear. Further, both gears are stopped in a state in which the backlash removing gear is relatively rotated with respect to the main gear up to the end where the pressed body is pressed in the circumferential direction and is movable. In this state, the phase of the backlash-removing gear is set so as to be shifted to the direction in which the backlash-removing gear acts on the backlash-removing gear with respect to the main gear so that the backlash can be removed. A phase difference can be provided. In addition, from the state where the phase of the backlash elimination gear is shifted with respect to the main gear and stopped, to the state where both gears overlap, the backlash elimination gear is rotated in both forward and reverse directions against the repulsion force against the main gear. Can be. Rotational repulsion acting between the two gears described above,
Because the backlash removing gear can rotate a small angle relative to the phase difference between both gears and the main gear,
Similar to the operation described in the above (1), the backlash removing gear is applied to the backlash generated during the meshing, and the backlash can be removed.

Further, since the pressing body has a predetermined mass,
The fact that the rotational repulsion decreases with an increase in the rotational speed is also the same as the operation described in the latter part of the above (1).

(3) According to the gear device of claim 3,
The two backlash removal gears and the main gear that are superposed coaxially with the main gear are given the rotational repulsion force and the phase difference in opposite directions, so when the main gear rotates in both forward and reverse directions and transmits power, When power is transmitted from another gear to the main gear, or when two other gears are engaged with each other with the main gear sandwiched and power is transmitted in order from one other gear, regardless of the magnitude of the torque to be transmitted. Backlash can be removed.

Further, the point that the rotational repulsive force becomes smaller as the rotational speed increases is the same as the operation described in the latter part of (1) above.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which the gear device of the present invention is embodied will be described below with reference to the drawings. The gear device of this embodiment is fixed to the crankshaft of a four-cycle engine for a motorcycle and is used to transmit power to a balance gear that drives auxiliary gears such as a clutch gear and an oil pump. As described above, since the driving torque fluctuates depending on whether the accelerator is on or off as described above, and for each stroke in the cycle, rattling noise is likely to occur,
Backlash must be removed to prevent this. This rattling noise is particularly conspicuous in a low rotation range. Further, when the backlash is removed by the conventional technique, a friction noise is generated when the gears are engaged with each other in a high rotation range, and therefore this friction noise also needs to be eliminated.

(1) Gear Device Using One Backlash Removal Gear FIG. 1 is a front view of the gear device according to the present embodiment, and FIG. 1 is a sectional view showing the gear device of FIG. Figure 2 for I)
Respectively. As shown in FIG. 2, a main gear 2 is fixed to a shaft 1 for transmitting power, and a backlash removing gear 3 is overlapped coaxially with the main gear 2. The backlash removing gear 3 is not fixed to the shaft 1 but is fitted. Further, as shown in FIGS. 1 and 2, a hollow portion 4 having a substantially rectangular shape is provided in the root circle of the backlash removing gear 3 with four long sides oriented in the radial direction at 90 ° intervals. did. The hollow portion 4 forms a substantially rectangular parallelepiped within the tooth width. Spring 5 compressed in the hollow part 4
Is housed so as to be expandable and contractible in the radial direction, and a pressing body 6 is provided at one end of the spring 5 in the gear center direction. The pressing body 6 is a substantially U-shaped solid (see FIG. 1),
The pressing surface 8 contacting the pressed body 7 is inclined at a predetermined angle with respect to the surface perpendicular to the radial direction as shown in the figure. Further, the pressing body 6 is interlocked with the expansion and contraction of the spring 5, and the hollow portion 4
It was able to slide back and forth in the radial direction along the inner wall of the. Further, a columnar pressed body 7 is vertically provided from the side surface of the main gear 2 toward the backlash removing gear 3. The pressing surface 8 of the pressing body 6 and the pressed body 7
The main gear 2 and the backlash removing gear 3 are coaxially combined so that they come into contact with each other. Also,
When the pressed body 7 is pressed in the circumferential direction and moved to the end of the hollow portion 4, that is, the backlash removing gear 3 is relatively rotated with respect to the main gear 2 by the rotational repulsive force and stopped, Rush removal gear 3
The phase of the tooth is slightly shifted in the direction in which the repulsive force acts on the backlash removal gear 3.

From the above structure, a part of the force of the pressing body 6 pressing the pressed body 7 in the center direction is converted into a force of pressing the pressed body 7 in the circumferential direction. A rotation repulsion force is generated between the lash removal gear 3 and the lash removal gear 3. The rotational repulsion force between the two gears 2 and 3, the phase difference between the two gears 2 and 3, and the position at which the phase of the backlash removing gear 3 with respect to the main gear 2 has stopped and the phase of the two gears 2 and 3 are different. Between the overlapping position, the backlash removing gear 3 is rotatable in both the forward and reverse directions while relatively opposing the rotational repulsive force with respect to the main gear 2, so that the direction in which the rotational repulsive force acts on the backlash removing gear 3. When the gears 2 and 3 are rotated in the opposite direction (arrow A shown in FIG. 1) to transmit power to other gears (arrow B shown in FIG. 1), a backlash removing gear is applied to the backlash generated at the time of meshing. , Gear backlash can be eliminated. Further, the backlash can be removed even when the power is transmitted from another gear and the gears 2 and 3 rotate in the direction in which the rotational repulsive force acts on the backlash removal gear 3 (arrow B shown in FIG. 1). Further, the driving torque is set to two gears 2,
When the rotational repulsive force acting between the three is smaller, the backlash can be removed in any case without being limited to the above case.

As the number of rotations increases, the pressing member 6
Since the centrifugal force acting on is increased, the radially inward force due to the reaction force of the compressed spring 5 and the radially outward force due to the centrifugal force cancel each other out, and the radially inward force becomes smaller. For this reason, the rotational repulsion force between the two gears, which is a component of the radially inward force, also decreases as the rotational speed increases. Therefore, the friction noise generated when the rear surfaces of the gears mesh with each other in the high rotation range can be prevented by reducing the rotational repulsion acting between the gears 2 and 3. In the case of the proposed device, 200
At 0 rpm to 5000 rpm, the rotational repulsion force decreases and the rotational repulsion force may disappear. As a result, backlash can be removed in the low rotation speed range to prevent gear rattling noise that is noticeably generated in the low rotation speed range, and removal of the backlash can be canceled in the high rotation speed range to prevent generation of friction noise.

The relationship between the pressing body 6 and the pressed body 7 is not limited to the present embodiment, but is a structure in which a reaction force in the center direction by the compressed spring 5 is changed into a circumferential force to obtain a rotational repulsion force. If applicable, it is adaptable. The number of hollow portions 4 accommodating the springs 5 and the pressing bodies 6 may be arbitrary. Further, the hollow portion 4 is not limited to the structure of penetrating the inside of the tooth width of the backlash removing gear 3 as in this embodiment, but a concave portion is provided on the side surface of the backlash removing gear 3 facing the main gear 2 so that It is possible to adopt a structure in which a space for accommodating the spring 5 and the pressing body 6 is provided. The spring 5 can be replaced with another elastic body as long as it can apply a radially inward force to the pressing body 6. For the same reason, a force inward in the radial direction may be applied to the pressing body 6 by the attractive force of the spring 5.

(2) Gear device using two backlash removing gears A front view of a gear device using two backlash removing gears, which is another embodiment of the present invention (a view taken in the direction of arrows III-III in FIG. 4). )
FIG. 3 is a cross-sectional view of the gear device of FIG.
-II) is shown in FIG. As shown in FIG. 4, two backlash removal gears 3 are provided on both sides of the main gear 2, and each of the backlash removal gears 3 and the main gears 2 has the main gear 2 and the backlash removal shown in the above embodiment (1). The configuration with the gear 3 is provided. However, in each of the backlash removing gears 3, the pressing surface 8 was inclined in the opposite direction. For this reason, this is a gear device in which two backlash removing gears 3 are provided with rotational repulsion and phase difference in opposite directions to the main gear 2 respectively. In the case where the backlash removing gear 3 shown in the above embodiment (1) is a single gear device, as described above, the direction (the arrow B shown in FIG. 1) opposite to the direction in which the rotational repulsion acts on the backlash removing gear 3 (see FIG. 1). When the gear device of the embodiment (1) is rotated to the arrow A) shown in FIG. 1 and power is transmitted from the gear device of the embodiment (1) to another gear, and when power is transmitted from the other gear. The backlash can be removed when the gear device of (1) is driven in a direction (arrow B shown in FIG. 1) in which a rotational repulsive force acts on the backlash removing gear 3. On the contrary, other gears can be removed. Is driven in the direction (arrow A shown in FIG. 1) opposite to the direction (arrow B shown in FIG. 1) in which power is transmitted to the gear device of the embodiment (1) and the rotational repulsion acts on the backlash removing gear 3. And the gear device of the embodiment (1) When the transmission torque is smaller than the rotation repulsive force acting between the two gears 2 and 3 when the power is transmitted to the other gear by rotating in the direction (arrow B shown in FIG. 1) in which the rotational repulsive force acts on the gear removal gear 3. Other than that, backlash is not removed.
On the other hand, in the gear device, since the two backlash removal gears 3 are provided with the rotational repulsive force and the phase difference in the opposite directions, respectively, the backlash of the gears is removed and the rattling noise can be prevented even in the above case. Become. Furthermore, FIG.
As shown by the phantom line in FIG. 2, when two other gears are combined with the gear device sandwiched therebetween and power is transmitted in order from the one other gear, in the gear device of the embodiment (1) Although the backlash cannot be removed by the combination, the backlash is removed by both the meshes in the gear device, and the rattling noise can be prevented by the both meshes. In addition, even in the gear device of the present embodiment, the rotational repulsion acting between the two gears 2 and 3 decreases as the rotational speed increases, and the friction noise can be reduced.

[0026]

According to the gear device of the present invention having the above configuration, the following effects can be obtained.

(1) Since the backlash of the gears can be eliminated by the rotational repulsive force and the phase difference applied to the main gear and the backlash removing gear, teeth generated at a portion where the two gears mesh when the transmitted torque fluctuates. Hitting noise can be prevented.

Further, since the rotational repulsive force decreases with an increase in the rotational speed, the force for pinching the teeth of the meshing mating gear is released, and the friction noise generated during the meshing with the increase in the rotational speed can be eliminated. In other words, it is possible to prevent the occurrence of remarkable rattling noise in the low rotation speed range and the generation of frictional noise at the time of meshing which becomes remarkable as the rotation speed increases. Therefore, it is possible to meet the demand for quietness of motorcycles, automobiles and the like in which the gear device is used.

(2) According to the gear device of the second aspect,
The effects described in the above (1) can be exerted by a structure, handling, maintenance, and the like that are substantially the same as those of the conventional technology.

(3) According to the gear device of the third aspect,
The two backlash removing gears coaxially superimposed on the main gear are provided with a rotational repulsion force and a phase difference with respect to the main gear in opposite directions, respectively, so that the main gear rotates in both forward and reverse directions to transmit power, and Backlash can be removed in all cases, such as when power is transmitted from another gear to the main gear, and rattling noise generated when both gears mesh with each other can be prevented. Further, also in the present gear device, the rotational repulsive force becomes smaller as the number of rotations increases, and the frictional noise generated when the gears are meshed can be reduced, which is the same as the effect described in the above (1).

[Brief description of drawings]

FIG. 1 is a front view showing a gear device according to an embodiment (1) of the present invention.

FIG. 2 is a cross-sectional view showing the gear device of FIG. 1 (when the cutting line is II shown in FIG. 1).

FIG. 3 is a front view (a view taken along the line III-III in FIG. 4) showing a gear device and the like according to the embodiment (2) of the present invention.

FIG. 4 is a cross-sectional view showing the gear device of FIG. 3 (when the cutting line is II-II shown in FIG. 3).

FIG. 5 is a front view showing a conventional gear device for removing backlash.

FIG. 6 is a sectional view showing the gear device of FIG. 5 (when the cutting line is III-III shown in FIG. 5).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft 2 Main gear 3 Backlash removal gear 4 Hollow part 5 Spring 6 Pressing body 7 Pressed body 8 Pressing surface

Claims (3)

[Claims] 1. A main gear for transmitting power, and a backlash removing gear that is coaxially overlapped with the main gear,
The gears are relatively rotatably mounted in a minute angle range including the state where the phases of the both gears match each other, and impart a force repulsive in the rotational direction to the backlash removal gear and the main gear, and a force repulsive in the rotational direction. This is a gear device in which the phase of the backlash removal gear is shifted in the direction in which the backlash is removed to the extent that the backlash can be removed, and a pressing body is attached to one of the two gears so that it can move radially Is attached to the pressing body, and the other gear is in contact with the pressing body and exerts on the pressing body a contact force including a component force in the outward radial direction and in the circumferential direction. The gear device is characterized by fixing. 2. The one gear to which the pressing body and the elastic body are attached is the backlash removing gear, the other gear to which the pressed body is fixed is the main gear, and the elastic body is a back gear. One or a plurality of compressed springs housed in the tooth width of the lash removing gear in the radial direction, and the pressing body is attached to one end of the spring near the shaft center of the gear, and the pressing surface is attached to the shaft of the gear. The pressed body is inclined in a certain direction with respect to a plane perpendicular to the radial direction while maintaining parallel with the pressing body, and the pressed body is provided on the side surface of the main gear toward the backlash removal gear and is housed in the backlash removal gear. The gear device according to claim 1, which is brought into contact with the pressing surface of the body. 3. The gear device according to claim 2, wherein another backlash removing gear is coaxially superimposed, and the backlash removing gear has the same structure as the other backlash removing gear but is pressed. On the other hand, on the side surface of the main gear, a pressed body is provided so as to project toward the backlash removing gear, and is brought into contact with the pressing surface of the pressing body in the backlash removing gear. apparatus.