JP2002147575A - Gear, reduction gear mechanism and electric steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear provided with a lubricant flow control means capable of suppressing the decrease of a lubricant at a mesh part caused by the flow of the lubricant applied to a tooth part, outside the tooth part following the rotation, and to provide an electric steering system provided with the gear. SOLUTION: A fluid lubricant is moved along guide members 21a, 21a provided at the tooth part 21 of a worm 2, to adhere to a worm wheel 3 and returned to the mesh part following the rotation of the worm wheel 3 or forcibly returned to the mesh part by the force of air generated by blasting members provided at shaft parts 22, 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear having means for controlling the flow of a lubricant, a reduction gear mechanism having the gear, and an electric steering device having the reduction gear mechanism.

[0002]

2. Description of the Related Art An electric steering apparatus includes a steering wheel having an input shaft connected to a steered wheel, and an output shaft connected to the input shaft via a torsion bar twisted by the action of a steering torque applied to the steered wheel. Shaft, a torque sensor that detects a steering torque based on a relative displacement amount of the output shaft and the input shaft in a rotation direction, and a direction in which the steering torque acts based on a detection result of the torque sensor in accordance with the magnitude of the steering torque. And a reduction gear mechanism for transmitting an output of the motor to the steering shaft.

FIG. 9 is a cross-sectional view perpendicular to the steering shaft, showing a configuration of a reduction gear mechanism and a motor portion of a conventional electric steering device.

In FIG. 1, reference numeral 100 denotes a worm gear type reduction gear mechanism. The reduction gear mechanism 100 includes a worm 101 and a worm wheel 102. The tooth portion 101a of the worm 101 has a cylindrical screw shape, and has shaft portions at both axial ends of the tooth portion 101a. One end of the shaft is connected to an output shaft of a motor 103 for assisting steering.

The worm 101 is inserted into the worm housing of the housing with the rolling bearings 104 and 105 fitted on the shafts at both ends. In the worm receiving portion, the dimension between the fitting portions into which the two rolling bearings 104 and 105 are fitted is equal to the dimension of the fitting portion, and the worm 101 is inserted from one of the fitting portions. The rolling bearings 104 and 105 are configured to be fitted to both fitting portions. Tooth portion 102a of the worm wheel 102
In addition, a highly viscous lubricant G (for example, grease) is applied to the tooth portion 101a in order to suppress wear that increases with time.

In the above configuration, when the rotation of the motor 103 is transmitted to the worm 101 and the meshing position between the tooth portion 101a of the worm 101 and the tooth portion 102a of the worm wheel 102 changes, the tooth portion 101a and the tooth The lubricant G applied to the portion 102a is scraped from the bottom of the tooth to the tip of the tooth, and the tooth 101a and the tooth 10
Although the amount of the lubricant near the meshing portion with which 2a meshes temporarily increases, the viscosity of the lubricant G is increased due to the viscosity of the tooth portion 101a.
a and the teeth 102a.

[0007]

However, the tooth 1
01a and the lubricant G applied to the teeth 102a
Of the teeth 101a, 10a due to poor lubrication caused by lack of the lubricant G at the meshing portion.
The amount of wear of 2a increases, and abnormal noise occurs.

As a result of pursuing the cause of the decrease in the amount of the lubricant G, the lubricant G applied to the teeth 101a and 102a with the rotation of the worm 101 is added to the tooth profile of the teeth 101a. The force which tends to flow in the direction of the tooth traces along the
When the amount of lubricant near the meshing portion temporarily increases due to a change in the meshing position between the gear portion a and the tooth portion 102a of the worm wheel 102, the lubricant G in the portion where the amount of lubricant increases is reduced. Since the tooth 101a of the worm 101, which has a cylindrical screw shape, has a thread shape, the tooth portion 101a of the cylindrical worm 101 has a thread shape. Is the tooth 10
1a, disperses in the axial direction along the tooth traces, and eventually moves from both axial ends of the tooth portion 101a to the outside of the tooth portion 101a, so that the amount of the lubricant G applied to the meshing portion Was found to decrease gradually.

Further, the reduction gear mechanism 10 of the electric steering device is provided.
0 indicates that the rotation speed of the worm 101 that rotates in conjunction with the rotation of the motor 103 is 1000 to 2000 rpm,
Since the worm 101 rotates at a relatively high speed as compared with the worm wheel 102, a part of the lubricant G applied to the worm 101 is repelled by centrifugal force accompanying the rotation of the worm 101, and the repelled lubricant G is removed. It will adhere to the inside of the housing supporting the worm 101,
Further, the worm housing portion of the housing is formed to have the same size over the entire length, and since there is a relatively large space between the worm 101 and the tooth tip surface of the worm 101, the amount of the lubricant G adhering to the inside of the housing is reduced. Has been found to be relatively large, and the amount of the lubricant retained in the teeth gradually decreases.

The present invention has been made based on such knowledge, and a main object of the present invention is to provide a gear capable of solving a shortage of lubricant at a meshing portion, a reduction gear mechanism including the gear, and an electric steering device. To provide.

Another object of the present invention is to provide a gear capable of favorably retaining a lubricant applied to a tooth portion for a long period of time.

[0012]

According to a first aspect of the present invention, a gear is provided.
In a gear provided with a shaft portion at an axial end of a tooth portion, a substantially frustoconical guide member for guiding a lubricant is provided on the tooth portion or the shaft portion with a small-diameter upper bottom portion facing the center in the axial direction. It is characterized by having.

According to the first aspect, when the lubricant applied to the teeth of the gear flows with the rotation of the gear and flows out of the teeth from the axial ends of the teeth. The lubricant that has flowed out flows along the tapered surface of the guide member in the radially-centrifugal direction of the guide member and adheres to the teeth of the gear that meshes with the gear. Returned to

[0014] A gear according to a second aspect of the present invention is characterized in that, in a gear provided with a shaft portion at an axial end of a tooth portion, a blowing member for blowing air toward the tooth portion is provided on the shaft portion. .

According to the second aspect of the present invention, the lubricant applied to the teeth of the gear flows out of the teeth with the rotation of the gear, and the lubricant in the meshing portion decreases. In response to wind blowing from the shaft portion toward the tooth portion generated by the blowing member with the rotation of the gear, the flowing lubricant is returned to the meshing portion.

According to a third aspect of the present invention, there is provided a gear having a shaft portion at an axial end of a tooth portion, wherein a flow suppressing protrusion for suppressing a flow of a lubricant applied to the tooth portion to a shaft portion side. Is provided between the tooth portion and the shaft portion.

The gear according to a fourth aspect of the present invention is characterized in that the flow suppressing projection is formed in a circular shape protruding from the entire peripheral surface of the axial end of the tooth portion.

According to the third and fourth aspects of the present invention, when the lubricant previously applied to the tooth portion flows from the tooth portion to the shaft portion by the rotation of the small gear, the flow of the lubricant is suppressed. The protrusion can be suppressed, and the outflow of the lubricant from the tooth portion can be reduced as compared with the case where the flow suppression protrusion is not provided, so that the lubricant can be favorably retained for a long period of time.

According to a fifth aspect of the present invention, there is provided a reduction gear mechanism comprising: a small gear having a tooth portion and a shaft portion; a large gear meshing with the small gear;
A reduction gear mechanism comprising: a housing rotatably supporting the shaft; and a lubrication applied to the teeth at a position near the tooth tip surface of the teeth at an inner side of the housing facing the teeth. It is characterized by having a scattering suppressing portion for suppressing scattering of the agent due to centrifugal force.

A reduction gear mechanism according to a seventh aspect of the present invention is characterized in that the scatter suppressing portion has a circular surface having a distance substantially equal to a tooth tip surface of the tooth portion.

In the fifth invention and the seventh invention, since the space between the tip surface of the small gear and the scattering suppressing portion inside the housing is narrow, the lubrication splashed from the small gear by centrifugal force. The amount of the agent adhering to the inside of the housing can be reduced as compared with the case where the scattering suppressing portion is not provided, and the lubricant can be favorably held for a long period of time.

A reduction gear mechanism according to a sixth invention is characterized in that the small gear is the gear described in any one of claims 1 to 4.

According to the sixth aspect of the present invention, the amount of the lubricant splashed from the pinion by the centrifugal force on the inside of the housing can be reduced as compared with the case where the scattering suppressing portion is not provided, and further, the teeth can be reduced. The flow of the lubricant from the portion to the shaft portion side can be suppressed by the flow suppression protrusion, and the outflow of the lubricant from the tooth portion can be reduced as compared with the case where the flow suppression protrusion is not provided. Therefore, the lubricant can be favorably retained for a long period of time.

According to an eighth aspect of the present invention, there is provided a reduction gear mechanism, wherein a plurality of lubricants to be scattered in the radial direction of the shaft portion between the tooth portion and the shaft portion of the pinion are provided. It is characterized in that the projections are spaced apart in the circumferential direction.

According to the eighth aspect, the lubricant flowing from the tooth portion of the small gear toward the shaft portion can be splashed in the radial direction by the convex piece. At this time, since the space between the convex piece and the scattering suppressing portion of the housing is relatively small, the lubricant can be splashed toward the gear teeth along the scattering suppressing portion. The lubricant attached to the teeth is returned to the meshing portion with the small gear with the rotation of the large gear, so that the amount of the lubricant can be greatly reduced.

A ninth aspect of the invention is directed to a reduction gear mechanism, wherein the scattering suppressing portion is formed of a cylindrical member having an insertion hole into which a meshing portion of the large gear with the small gear is inserted.

According to the ninth aspect, the space between the tip surface of the pinion and the cylindrical member inside the housing can be made relatively narrow, so that the lubrication splashed from the pinion by centrifugal force. The amount of the agent adhering to the inside of the housing can be reduced as compared with the case where the tubular member is not provided, and the lubricant can be favorably held for a long period of time. Moreover, since the cylindrical member is provided inside the housing, the supporting structure of the small gear to the housing can be made the same as the existing structure, and this supporting structure can be processed by the existing processing steps, and the cost can be reduced. Can be reduced.

An electric steering apparatus according to a tenth aspect of the present invention is the electric steering apparatus according to claim 1 or 2, which is connected to a rotating shaft of a steering assist motor, and meshes with the gear to rotate the motor. And a gear for transmitting the rotation of the motor to the steering shaft to assist the steering.

According to the tenth aspect, the electric rudder includes a gear for returning the flowing lubricant to the engagement portion autonomously by the guide member, or a gear for forcibly returning the flowing lubricant to the engagement portion by the blowing member. Since the lubricating device can effectively retain the lubrication of the meshing part for a long period of time, the abnormal noise caused by insufficient lubrication caused by insufficient lubrication of the meshing part and increased wear of the tooth part is generated. Can be reduced.

According to an eleventh aspect of the present invention, there is provided an electric steering apparatus comprising: a reduction gear mechanism according to any one of claims 5 to 9; a steering assist motor connected to a shaft of the small gear; And a transmitting means for transmitting the torque of the large gear accompanying the rotation of the motor to a steering mechanism.

According to the eleventh aspect, the amount of the lubricant applied to the teeth in advance can be reduced in the axial direction, and the housing of the lubricant splashed from the small gear by the centrifugal force can be reduced. Since the amount of adhesion to the inside can be reduced, the lubricant can be more favorably retained over a long period of time.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments.

Embodiment 1 FIG. 1 is a longitudinal sectional view of an electric steering device according to the present invention, and FIG. 2 shows a configuration of a reduction gear mechanism and a motor portion of the electric steering device including a gear according to the first invention. It is sectional drawing perpendicular to a steering shaft.

In the figure, reference numeral 5 denotes a steered wheel, which is connected to an input shaft 6. The input shaft 6 is a torsion bar 7
To the output shaft 8 to form a steering shaft. Further, a torque sensor 9 is attached to the steering shaft, and a motor control circuit (not shown) controls the motor 4 for assisting steering based on the detection result of the torque sensor 9.

The output shaft 4a of the motor 4 is connected to the output shaft 8
Is connected to a shaft portion 22 at one end of the worm 2 disposed so as to be orthogonal to the axis of the worm 2. The worm 2 is a cylindrical worm, and has tooth portions 21 each having a cylindrical screw shape, and has shaft portions 221 and 222 at both ends in the axial direction of the tooth portions 21. The shaft portions 221 and 222 are rotatably supported by bearings B1 and B2.

The worm wheel 3 is fitted and fixed in the middle of the output shaft 8 so that the teeth 31 formed on the outer periphery mesh with the center of the teeth 21.

A highly viscous lubricant G (eg, grease) is applied to the teeth 31 and the teeth 21.

At both ends of the teeth 21 in the axial direction, the teeth 21
Frustoconical guide members 21a1, 21a having holes 21b1, 21b2 for fitting into the shaft cores.
2, the small diameter upper bottom portions 21c1 and 21c2
Are fitted and fixed toward the center in the axial direction. The guide members 21a1 and 21a2 are provided at both ends of the tooth 21 and the tooth 3
1 and the taper surfaces 21d1, 21d
Part of the worm wheel 2 is installed at a position along the outer periphery of the worm wheel 3.

In the gear structure described in detail above, the lubricant G, which has moved to the outside of the teeth 21 of the worm 2 with the rotation of the worm 2, moves along the tapered surfaces 21d1, 21d2 of the guide members 21a1, 21a2. And fluid, lubricant G
Of the worm wheel 3 due to the viscosity of the worm wheel 3. The sticking lubricant G is returned to the meshing portion 20 with the rotation of the worm wheel 3, whereby the lubricant of the meshing portion 20 is held autonomously.

Incidentally, the tapered surfaces 21d1, 21d2 of the guide members 21a1, 21a2 may be concave. In addition to the embodiment in which the guide members 21a1 and 21a2 separate from the tooth portion 21 are fitted and fixed to the tooth portion 21, the guide members 21a1 and 21a2 may be formed integrally with the tooth portion 21. Guide members 21 a 1 and 21 a 2 separate from 21 may be provided on the shaft portions 221 and 222, respectively, near the tooth portion 21.

In the configuration of the electric steering apparatus described in detail above, when a steering torque is applied to the steered wheels 5, the torque sensor 9 detects the relative displacement of the input shaft 6 and the output shaft 8 in the rotation direction. The steering torque is detected. The motor 4 generates a rotational force in the direction in which the steering torque acts based on the detection result of the torque sensor 9 in accordance with the magnitude of the steering torque. The rotation of the motor 4 is transmitted to the worm 2 so that the worm 2 rotates. With the rotation of the worm 2, the lubricant G initially applied to the teeth 21 is
The worm 2 reduces the amount of lubricant flowing in the meshing portion by flowing to the outside of the guide member 21a1,
It returns to the meshing part 20 autonomously by 21a2. Therefore, the electric steering device including the worm 2 can effectively retain the lubricant in the meshing portion 20 for a long period of time.

Embodiment 2 FIG. 3A is a cross-sectional view perpendicular to a steering shaft, showing a configuration of a reduction gear mechanism and a motor portion of an electric steering device provided with a gear according to the second invention, and FIG. 3B is a perspective view of a blowing member. FIG. The configuration of the reduction gear mechanism and the motor part in the figure is the same as that of the first embodiment. The structure of the reduction gear mechanism and the motor portion is the same as that of the above-described guide member 21.
blower members 22a1, 22a2 instead of a1, 21a2
Are provided on the shaft portions 221 and 222. The blowing member 22a
1 and 22a2 have shaft portions 221 and 2
22, having disks 22b1 and 22b2 fitted and fixed to
On the outer periphery of the disks 22b1 and 22b2,
Plural blades 22c1, which blow with the rotation of 222
22c2 is provided.

In the gear structure described in detail above, the air blowing function of the air blowing members 22a1 and 22a2 causes
The lubricant G is more positively engaged with the engagement portion 2 than in the first and second a1, 21a2.
It can be returned to zero. At this time, one of the blowing members 22
The wind generated by a1 does not interfere with the wind generated by the other blowing member 22a2. That is, when the worm 2 rotates clockwise as viewed from the motor side in FIG. 3A (X direction), as described above, the lubricant G in the portion where the lubricant amount has temporarily increased becomes large.
Flows in the direction of the shaft portion 222 on the motor 4 side (Y direction) along the tooth shape of the tooth portion 21, and in order to control this flow, a blowing member 22 a 2 provided on the shaft portion 222 on the motor 4 side is driven by the shaft portion 222. To the meshing portion 20 to return the flowing lubricant G to the meshing portion 20. At this time, the blower member 22a1 on the side opposite to the motor blows air in the direction opposite to the motor 4 (X direction), so that the blower in the direction of the engagement portion 20 is not obstructed. When the worm 2 rotates counterclockwise (X direction) as viewed from the motor side in FIG. 3A, the lubricant G flows along the tooth shape of the tooth portion 21 toward the shaft portion 221 on the opposite side to the motor 4. In order to control the flow, the blowing member 22a1 provided on the shaft 221 opposite to the motor 4 blows air from the shaft 221 toward the meshing portion 20, so that the flowing lubricant G
Is returned to the engagement portion 20. At this time, the blowing member 2 on the opposite side
2a2 is for blowing air to the motor 4 side.
There is no hindrance to the airflow in the zero direction. As a result, the lubricant G of the engagement portion 20 is forcibly held.

As described above, since the moving direction of the lubricant G is different depending on the rotation direction of the worm 2, the blowing members 22a1, 22a are adapted to cope with the behavior of the lubricant G.
The orientation of the second blade is taken into account.

In the configuration of the electric steering device described in detail above, the first embodiment will be described. As in the case of the electric steering device, the lubricant G initially applied to the tooth portion 21 flows to the outside of the tooth portion 21 as the worm 2 rotates, and the lubricant G in the meshing portion 20 decreases. The worm 2 forcibly returns the flowing lubricant G to the meshing portion 20 by the blowing members 22a1 and 22a2. Therefore, the electric steering device including the worm 2 can effectively hold the lubricant G of the meshing portion 20 for a long period of time.

Embodiment 3 FIG. 4 is a front view showing the configuration of the gear according to the third and fourth inventions. The configuration of the gears in the figure is the same as in the first embodiment. Is the same as the gear configuration in
Instead of the guide members 21a1 and 21a2, the flow suppressing protrusions 10a and 10b that suppress the flow of the lubricant G applied to the tooth portion 21 to the shaft portions 221 and 222 are replaced with the tooth portion 21.
And shaft portions 221 and 22 connected to both axial ends of the tooth portion 21
Between the two.

Both end portions of the tooth portion 21 have non-tooth portions 23a and 23b having the same size as the tooth portion 21.
The flow suppressing protrusions 10a and 10b are provided on the a and 23b.

The flow suppressing protrusions 10a and 10b are formed in a circular shape protruding integrally from the entire peripheral surfaces of the non-tooth portions 23a and 23b, and the lubricant flows from the tooth portion 21 to the shaft portions 221 and 222. The flow of G is suppressed.

The gear A thus configured is used, for example, as the worm 2 of the reduction gear mechanism 1a. FIG. 5 is a sectional view of the reduction gear mechanism. This reduction gear mechanism 1a includes a worm wheel 3 that meshes with the teeth 21 of the worm 2.
And bearings B1 and B2 formed of rolling bearings fitted to the respective shaft portions 221 and 222, and a housing 11 rotatably supporting the worm 2 via the bearings B1 and B2. The rotation of the motor 4 connected to the shaft portion 22 is reduced and transmitted to the worm wheel 3.

The housing 11 is elongated in the axial direction of the worm 2, and has a first fitting hole 11
a and a screw hole 11b are provided, and a second fitting hole 11c and a screw hole 11d are provided at the other end. Further, the inside facing the tooth portion 21, in other words, the first and second holes are provided. Between the fitting holes 11a and 11c, there is provided a scattering suppressing portion 11e which suppresses scattering of the lubricant applied to the tooth portion 21 due to centrifugal force at a position near the tooth tip surface of the tooth portion 21. ing.

When the housing 11 is formed, the scattering suppressing portion 11e has a smaller diameter than the fitting holes 11a and 11c, and the distance between the scattering suppressing portion 11e and the tooth tip surface of the tooth portion 21 is substantially equal to each other. And the scatter control unit 11
e on one side in the circumferential direction of the worm 2
An insertion hole 11f into which the engagement portion 20 is inserted is formed.

A lid 12 for closing the other end of the housing 11 is screwed into the other screw hole 11d, and the other bearing B1 is fixed by the lid 12. A screw ring 13 for fixing one bearing B2 is screwed into one screw hole 11b.

The thus configured reduction gear mechanism 1a
Is used in the electric steering device shown in FIG. The shaft 222 of the worm 2 is connected to the output shaft 4a of the motor 4, and the worm wheel 3 is fitted and fixed at the middle of the output shaft 8, and the worm 2 and the worm wheel 3 The rotation of the output shaft 4a is reduced and transmitted to the output shaft 8, and transmitted from the output shaft 8 via a universal joint to, for example, a rack and pinion type steering mechanism (not shown). The output shaft 8 and the universal joint constitute transmission means for transmitting the rotational force of the worm wheel 3 to the steering mechanism.

When the worm 2 is incorporated in the electric steering apparatus equipped with the reduction gear mechanism 1a as described above, for example, the worm 2 fitted with one bearing B2 is inserted into the housing through the first fitting hole 11a. 11 and one of the bearings B2 is fitted into the first fitting hole 11a.
By screwing the screw 3 into the screw hole 11b, the motor-side shaft portion 222 of the worm 2 can be supported by the housing 11, and the movement of the worm 2 in the axial direction can be restricted.

Next, the inner peripheral surface of the other bearing B1 is provided on the shaft portion 221 of the worm 2, and the outer peripheral surface thereof is provided on the second fitting hole 11.
The shaft portion 221 of the worm 2 can be supported by the housing 11 by fitting the cover 12 into the screw hole 11d. When the worm 2 is assembled in this manner, a lubricant G made of grease is applied around the worm 2 and on the meshing portion 20 of the worm wheel 3 with the worm 2.

When the motor 4 is driven with the lubricant G applied in this manner to assist the steering, most of the lubricant G is held by the worm 2 and the worm wheel 3 due to its viscosity. Some of the lubricant G flows in the axial direction while flowing in the tooth ridge direction along the tooth shape of the worm 2. The lubricant G flowing in the axial direction is applied to the non-tooth portion 2
Flow suppression protrusions 10a, 10b provided on 3a, 23b
Accordingly, the flow can be suppressed, so that a decrease in the lubricant G can be reduced. Further, the flow suppression protrusions 10a and 10b and the scattering suppression portion 11e of the housing 11 are provided.
Is relatively small, the lubricant running on the peripheral surfaces of the flow suppression protrusions 10a and 10b is splashed toward the teeth 31 of the worm wheel 3 by centrifugal force, and the teeth are removed. 31. This tooth part 3
The lubricant adhering to 1 is returned to the meshing portion 20 with the worm 2 as the worm wheel 3 rotates, and the lubricant G decreases very little.

A part of the lubricant G applied to the meshing portion 20 is repelled by the centrifugal force caused by the rotation of the worm 2, and the repelled lubricant is applied to the housing 1.
However, since the space between the scattering suppressing portion 11e and the tooth portion 21 of the worm 2 is very small as compared with the case where the scattering suppressing portion 11e is not provided, The amount of adhesion to the housing 11 side can be reduced as compared with the case where the scattering suppression portion 11e is not provided, and the lubricant G can be favorably retained for a long period of time. Moreover, since the lubricant G can be satisfactorily held for a long period of time as described above, the amount of the lubricant applied to the meshing portion 20 in advance can be reduced by the flow suppressing protrusions 10a and 10b and the scattering suppressing portion 11e. The number can be reduced as compared with those not provided, and the cost can be reduced.

In the third embodiment described above,
The flow suppressing protrusions 10a and 10b are provided on the non-tooth portions 23a and 23b.
b, and the non-tooth portions 23a and 23b and the shaft portion 22
Alternatively, they may be formed in an annular shape separately from the first and second parts 222 and 222 and fixed to the non-tooth parts 23a and 23b or the shaft parts 221 and 222 by fixing means such as press fitting. In this case, the flow suppressing protrusions 10a, 10
Since b can be formed, the cost can be reduced.

Embodiment 4 FIG. FIG. 6 is a sectional view showing the configuration of the reduction gear mechanism of the fourth embodiment. Embodiment 4
The reduction gear mechanism 1a has a configuration in which the scattering suppressing portion 11e is provided inside the housing 11 in place of the flow suppressing protrusions 10a and 10b.
A plurality of convex pieces 14a and 14b are provided on the peripheral surfaces of the a and 23b so as to be spaced apart in the circumferential direction.

The protruding pieces 14a, 14b are
b, but other than the non-tooth portions 23a,
A plurality of fitting cylinders may be provided so as to protrude from the fitting cylinder fitted to the fitting cylinder 23b, and the fitting cylinder may be fixed by fitting to the non-teeth portions 23a and 23b.

In the fourth embodiment, when a part of the lubricant G applied to the meshing portion 20 flows between the convex pieces 14a and 14b due to the rotation of the worm 2, the convex pieces 14a and 14b
14b can be bounced in the radial direction. In this case, since the interval between the convex pieces 14a, 14b and the scattering suppressing portion 11e of the housing 11 is relatively small, the distance from the insertion hole 11f to the tooth portion 31 of the worm wheel 3 along the scattering suppressing portion 11e. Can bounce off. The lubricant attached to the teeth 31 is returned to the meshing portion 20 with the worm 2 with the rotation of the worm wheel 3, and the lubricant G decreases very little.

Since other configurations and operations are the same as those of the first to third embodiments, the same reference numerals are given to the same components, and the detailed description and the description of the operations are omitted.

Embodiment 5 FIG. FIG. 7 is a cross-sectional view showing a configuration of a reduction gear mechanism according to Embodiment 5, and FIG. 8 is a cross-sectional view of a main part. In the reduction gear mechanism 1a according to the fifth embodiment, instead of forming the scattering suppressing portion 11e integrally with the housing 11, the scattering suppressing portion 11e is formed separately from the housing 11, and the scattering suppressing portion 11e is formed of the housing 11. It is fitted inside.

The anti-scattering portion 11e is composed of a cylindrical member 11g having a substantially C-shaped cross section and having an insertion hole 11f into which the meshing portion of the worm wheel 3 with the worm 2 is inserted. The diameter of the cylindrical member 11g is slightly reduced. In this state, it is fitted inside the housing 11 and is fixed by its restoring force.

In the fifth embodiment, the scattering suppression unit 11
Since e is formed separately from the housing 11, the supporting structure of the worm 2 to the housing 11 can be made the same as that of the existing structure, and this supporting structure can be processed by the existing processing steps, thereby reducing the cost. Can be achieved.

The scattering suppressing portion 11e has a structure having an insertion hole 11f over its entire length and an insertion hole 11f between both ends.
May be provided. In this case, the scattering suppression unit 11
e is fixed inside the housing 11 by, for example, press fitting.

Since other structures and operations are the same as those of the first to fourth embodiments, the same reference numerals are given to the same components, and the detailed description and the description of the operations are omitted.

The gear of the embodiment described above may be not only a cylindrical worm but also a drum-shaped worm, or a hypoid pinion having straight teeth or curved teeth. Further, the reduction gear mechanisms of the fourth and fifth embodiments may be applied to the electric steering devices of the first to third embodiments.

The gear of the present invention may be provided in a gear mechanism other than the reduction gear mechanism of the electric steering device. Further, the reduction gear mechanism of the present invention may be used for other than the electric steering device.

[0070]

As described in detail above, according to the gears of the first and second inventions and the electric steering device of the tenth invention, a guide member or a blowing member is provided on the gear as lubricant flow control means. Thus, the lubricant flowing by the rotation of the gear and moving from the meshing portion to the outside of the tooth portion can be returned to the meshing portion. As a result, it is possible to reduce a decrease in the amount of the lubricant in the meshing portion as compared with the case where the lubricant flow control means is not provided. Therefore, the lubricant is sufficiently applied to the tooth surface, and the wear of the gear and the gear meshing with the gear, which has been promoted by the decrease of the lubricant, is suppressed, and the durability of the gear mechanism increases.

Further, since the wear of the gears and the gears meshing with the gears, which has been promoted by the reduction of the lubricant, is suppressed, poor lubrication of the meshing portions is reduced, and generation of abnormal noise due to backlash can be prevented. Becomes

Further, since the gear has a simple structure in which a guide member is provided on a tooth portion or a shaft portion of a gear, or a blowing member is provided on a shaft portion of the gear, the gear provided with the lubricant flow control means has a high temperature. The present invention has excellent effects such as being able to effectively retain a lubricant for a long period of time and satisfying durability strength even under circumstances (for example, when mounted in an engine room).

According to the gears of the third and fourth inventions, the flow of the lubricant applied to the tooth portion from the tooth portion to the shaft portion can be suppressed by the flow suppression protrusion. As compared with the case where the protrusion is not provided, the outflow of the lubricant from the tooth portion can be reduced, and the lubricant can be favorably retained for a long period of time.

According to the reduction gear mechanisms of the fifth and seventh inventions, since the space between the tip surface of the small gear and the scattering suppressing portion inside the housing is small, the space is rebounded from the small gear by centrifugal force. The amount of the lubricant applied to the inside of the housing can be reduced as compared with the case where the scattering suppression portion is not provided, and the lubricant can be favorably retained for a long period of time.

According to the reduction gear mechanism of the sixth invention, the amount of the lubricant splashed from the small gear due to the centrifugal force on the inside of the housing can be reduced as compared with the case where the scattering suppressing portion is not provided. Further, the flow of the lubricant from the tooth portion to the shaft portion side can be suppressed by the flow suppression protrusion, and the outflow of the lubricant from the tooth portion is reduced as compared with the case where the flow suppression protrusion is not provided. Therefore, the lubricant can be favorably retained for a long period of time.

According to the reduction gear mechanism of the eighth invention, the lubricant flowing from the tooth portion of the small gear toward the shaft portion can be splashed in the radial direction by the convex piece, and furthermore, the scattering of the convex piece and the housing can be suppressed. Since the distance between the gear and the gear is relatively small, the lubricant can be splashed toward the gear teeth along the anti-scattering part. Accordingly, the lubricant is returned to the meshing portion with the small gear, so that the reduction of the lubricant can be extremely reduced.

According to the reduction gear mechanism of the ninth aspect, the space between the tooth tip surface of the small gear and the cylindrical member inside the housing can be made relatively narrow, so that the small gear is rebounded from the small gear by centrifugal force. The amount of the lubricant applied to the inside of the housing can be reduced as compared with the case where the cylindrical member is not provided, and the lubricant can be retained favorably over a long period of time. Moreover, since the cylindrical member is provided inside the housing, the supporting structure of the small gear to the housing can be made the same as the existing structure, and this supporting structure can be processed by the existing processing steps, and the cost can be reduced. Can be reduced.

According to the eleventh aspect of the present invention, the amount of lubricant previously applied to the teeth can be reduced in the axial direction, and at the same time, the lubricant is splashed off from the small gear by centrifugal force. Since the amount of the lubricant that adheres to the inside of the housing can be reduced, the lubricant can be retained more favorably over a long period of time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric steering device according to the present invention.

FIG. 2 is a cross-sectional view perpendicular to the steering shaft, showing a configuration of a reduction gear mechanism and a motor portion of the electric steering device including the gear according to the first invention.

FIG. 3A is a cross-sectional view perpendicular to a steering shaft, showing a configuration of a reduction gear mechanism and a motor portion of an electric steering device provided with a gear according to a second invention, and FIG. 3B is a perspective view of a blowing member; FIG.

FIG. 4 is a front view of a gear according to a third invention and a fourth invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a reduction gear mechanism according to a third embodiment.

FIG. 6 is a cross-sectional view illustrating a configuration of a reduction gear mechanism according to a fourth embodiment.

FIG. 7 is a cross-sectional view illustrating a configuration of a reduction gear mechanism according to Embodiment 5.

FIG. 8 is a sectional view of a main part of a reduction gear mechanism according to a fifth embodiment.

FIG. 9 is a cross-sectional view perpendicular to a steering shaft, showing a configuration of a reduction gear mechanism and a motor portion of a conventional electric steering device.

[Explanation of symbols]

 1a Reduction gear mechanism 2 Worm (small gear) 21 Teeth 21a1, 21a2 Induction member 221, 222 Shaft 22a1, 22a2 Blowing member 3 Worm wheel (large gear) 31 Teeth 4 Motor 4a Output shaft of motor B1, B2 Bearing 8 Output shaft (transmission means) 10a, 10b Flow suppression protrusion 11 Housing 11e Scattering suppression part 14a, 14b Convex piece

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F16H 57/04 F16H 57/04 B (72) Inventor Akihiko Shiina 3-5 Minamisenba, Chuo-ku, Osaka-shi, Osaka No. 8 Koyo Seiko Co., Ltd. F-term (reference) 3D033 CA02 CA04 JC08 3J009 DA15 EA06 EA19 EA23 EA32 EB24 EC02 FA08 FA14 3J030 AC01 BA03 BB16 BB18 CA10 3J063 AA01 AB03 AC01 BA11 CA01 CB01 XD02 XE17

Claims (11)

[Claims] 1. A gear provided with a shaft portion at an axial end of a tooth portion, wherein a substantially frusto-conical guiding member for guiding a lubricant has a small-diameter upper base directed axially toward the center side. Or a gear provided on the shaft portion. 2. A gear provided with a shaft portion at an axial end of the tooth portion, wherein a blowing member for blowing air toward the tooth portion is provided on the shaft portion. 3. A gear provided with a shaft portion at an axial end of a tooth portion, wherein the flow suppressing protrusion for suppressing the flow of a lubricant applied to the tooth portion toward the shaft portion is formed on the tooth portion and the shaft. A gear provided between the parts. 4. The gear according to claim 3, wherein the flow suppressing protrusion is a circular shape protruding from the entire peripheral surface of the axial end of the tooth portion. 5. A reduction gear mechanism comprising: a small gear having a tooth portion and a shaft portion; a large gear meshing with the small gear; and a housing rotatably supporting the shaft portion. A reduction gear, wherein the inside facing the portion has a scattering suppression portion that suppresses scattering of a lubricant applied to the tooth portion due to centrifugal force at a position near the tooth tip surface of the tooth portion. mechanism. 6. The reduction gear mechanism according to claim 5, wherein the small gear is the gear according to any one of claims 1 to 4. 7. The reduction gear mechanism according to claim 5, wherein the scattering suppressing portion has a circular surface having a distance substantially equal to a tooth tip surface of the tooth portion. 8. A plurality of convex pieces which are to be scattered in a radial direction of a shaft portion between a tooth portion and a shaft portion of the pinion to cause lubricant flowing from the tooth portion toward the shaft portion to be scattered in a radial direction of the shaft portion. The reduction gear mechanism according to claim 5, further comprising: 9. The reduction gear mechanism according to claim 5, wherein the scattering suppressing portion is formed of a cylindrical member having an insertion hole into which a meshing portion of the large gear with the small gear is inserted. 10. The gear according to claim 1, which is connected to a rotation shaft of a steering assist motor, and a gear that meshes with the gear to reduce the rotation of the motor and transmit the rotation to the steering shaft. And a steering assist device that transmits rotation of the motor to a steering shaft to assist steering. 11. A reduction gear mechanism according to claim 5, a motor for steering assistance connected to a shaft of said small gear, and rotation of said large gear with rotation of said motor. A transmission unit for transmitting a force to the steering mechanism.