CN221033888U

CN221033888U - Multistage speed reducer

Info

Publication number: CN221033888U
Application number: CN202322678261.6U
Authority: CN
Inventors: 猪爪和也
Original assignee: Mabuchi Motor Co Ltd
Current assignee: Mabuchi Motor Co Ltd
Priority date: 2023-10-07
Filing date: 2023-10-07
Publication date: 2024-05-28
Anticipated expiration: 2033-10-07

Abstract

The present disclosure provides a multistage speed reducer that combines the miniaturization, light weight, and rigidity of a gear box. The gear box of the multi-stage speed reducer comprises a box body and a box cover (100), wherein at least one of the box body and the box cover is provided with a plurality of hollow protruding parts (110, 120, 130, 140) for holding the central shaft of the gear in a way of facing the inner side of the speed reducer, and at two sides of at least one hollow protruding part, a linear reinforcing rib (131) is arranged in a way of along the direction of the stress applied by the central shaft of the held gear and the direction opposite to the direction of the stress.

Description

Multistage speed reducer

Technical Field

The present disclosure relates to the field of small motors, and in particular, to small multi-stage reducers.

Background

Nowadays, small motors represented by multi-stage speed reducers are widely used in various devices such as home appliances, in-vehicle devices, production devices, precision instruments, and information devices. With this, there is an increasing demand for downsizing, weight saving, and the like of the multi-stage speed reducer, and it is also desired that the housing of the multi-stage speed reducer has sufficient rigidity. A conventional multi-stage speed reducer includes a motor unit, a plurality of gears, and a gear case accommodating the motor unit and the gears, and a hollow protrusion for holding a shaft of the gears is provided on an inner wall of the gear case. However, during the operation of the multi-stage speed reducer, the hollow protrusions described above receive stress from the held shaft due to rotation of the gear or the like, and the stress may cause the hollow protrusions to deform and thereby cause vibration of the shaft. In view of this, patent document 1 proposes a compact gear motor, i.e., a multi-stage reduction gear, in which a projection holding an output shaft is surrounded by a plurality of ribs, at least one of which is oriented in the direction of a lateral force applied to the output shaft.

Patent document 1: CN111434011A

However, as is clear from an examination of fig. 7 of patent document 1, the ribs of patent document 1 support the protruding portion that holds the output shaft, and five ribs are provided around the protruding portion at equal angular intervals. Further, patent document 1 does not limit the direction of the rib around the other protruding portion, and does not consider the case where the gear rotates reversely. Accordingly, the number and arrangement of the ribs in patent document 1 have room for further improvement, and a multistage reduction gear that is compact, lightweight, and rigid is expected.

Disclosure of utility model

The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a multistage reduction gear that combines downsizing, weight saving, and rigidity of a gear box.

The multistage speed reducer of the present disclosure includes: a brushless motor unit; a plurality of gears driven to rotate by the brushless motor unit; and a gear case housing the brushless motor unit and the plurality of gears, the plurality of gears including: a primary drive gear; a primary driven gear engaged with the primary drive gear; a second-stage drive gear coaxially arranged with the first-stage driven gear; and a second-stage driven gear engaged with the second-stage driving gear, wherein a central shaft is provided at each of centers of the plurality of gears, the central shaft includes a first shaft provided at a center of the first-stage driving gear, a second shaft provided at a center of the first-stage driven gear and the second-stage driving gear, and a third shaft provided at a center of the second-stage driven gear, the gear case includes a case and a case cover, a plurality of hollow protrusions for holding the central shaft of the gear are provided at least one of the case and the case cover so as to face an inside of the speed reducer, and linear reinforcing ribs are provided at both sides of at least one of the hollow protrusions so as to extend in a direction of stress received by the central shaft of the gear to be held and in a direction opposite to the direction of the stress.

According to an embodiment of the present disclosure, the hollow protruding portions and the reinforcing ribs are provided in the case body and the case cover, and in the assembled state, the hollow protruding portions provided in the case body are disposed in one-to-one correspondence with the hollow protruding portions provided in the case cover, and the reinforcing ribs provided in the case body are disposed in one-to-one correspondence with the reinforcing ribs provided in the case cover.

According to an embodiment of the present disclosure, the reinforcing ribs are provided on both sides of the hollow protrusion portion that holds the second shaft.

According to an embodiment of the present disclosure, the first-stage drive gear has a number of teeth a and a modulus δ, the first-stage driven gear has a number of teeth B and a modulus δ, the second-stage drive gear has a number of teeth B and a modulus γ, the second-stage driven gear has a number of teeth c and a modulus γ, when the plurality of gears are viewed in plan along the first axis, any one of a straight line passing through the axis of the first axis and not passing through the axis of the second axis and the axis of the third axis is set as a reference line, an angle formed between a straight line passing through the axis of the first axis and the axis of the second axis and the reference line is set as α, an angle formed between a straight line passing through the axis of the second axis and the axis of the third axis and the reference line is set as β, a direction in which the reinforcing rib is disposed and the reference line is set as θ,

According to an embodiment of the present disclosure, the case body and the case cover are injection-molded pieces, and the reinforcing ribs provided at both sides of the hollow protruding portion are formed integrally with the hollow protruding portion by injection molding.

According to an embodiment of the present disclosure, auxiliary ribs are further provided at the case body and the case cover in such a manner as to face the inside of the speed reducer.

According to an embodiment of the present disclosure, the strength of the reinforcing rib is greater than the strength of the auxiliary rib.

According to an embodiment of the present disclosure, one end of the reinforcing rib is connected to the hollow protrusion, and the other end of the reinforcing rib is connected to the auxiliary rib.

According to an embodiment of the present disclosure, two or more rib members, which are the reinforcing ribs or the auxiliary ribs, are connected between the two hollow protrusions.

According to an embodiment of the present disclosure, a circuit board having printed wiring and a plurality of electronic components protruding from a surface is also housed in the gear case, the plurality of electronic components being housed in gaps formed between the rib members.

According to the embodiments of the present disclosure, a multistage speed reducer that is compatible with downsizing, weight saving, and rigidity of a gear box can be provided.

Drawings

The objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments thereof with reference to the accompanying drawings in which:

FIG. 1 illustrates a top view of a cover of a gearbox of a first embodiment of the present disclosure;

FIG. 2 illustrates a perspective view of a cover of a gearbox of a first embodiment of the present disclosure;

fig. 3 is a schematic view showing the arrangement direction of the reinforcing ribs;

FIG. 4 shows a top view of a cover of a gearbox of a second embodiment of the present disclosure;

Fig. 5 shows a perspective view of a cover of a gearbox of a second embodiment of the present disclosure.

Description of the reference numerals

100. 200 Case covers;

110. 120, 130, 140 hollow protrusions; 131 reinforcing ribs; 132 auxiliary ribs;

220 primary drive gears; 231 stage driven gear;

230 a secondary drive gear; 241 secondary driven gears;

320 a first shaft; a second axis 330; 340 a third axis; and L datum line.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is only exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, operations, and/or components, but do not preclude the presence or addition of one or more other features, operations, or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a convention should be made in the sense one having skill in the art would understand the convention (e.g., "a device having at least one of A, B and C" would include, but not be limited to, a device having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). It should also be appreciated by those skilled in the art that virtually any disjunctive word and/or phrase presenting two or more alternative items, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the items, either of the items, or both. For example, the phrase "a or B" should be understood to include the possibility of "a" or "B", or "a and B".

Embodiments of the present disclosure provide a multi-stage speed reducer. The multi-stage reduction gear comprises a brushless motor unit, a plurality of gears and a gear box. The plurality of gears are driven to rotate by the brushless motor unit. The gear case accommodates the brushless motor unit and the plurality of gears. The plurality of gears include a primary drive gear, a primary driven gear engaged with the primary drive gear, a secondary drive gear coaxially disposed with the primary driven gear, and a secondary driven gear engaged with the secondary drive gear. A central shaft is provided at the centers of the plurality of gears, respectively, and includes a first shaft provided at the center of the primary drive gear, a second shaft provided at the centers of the primary driven gear and the secondary drive gear, and a third shaft provided at the center of the secondary driven gear. The gear case includes a case body and a case cover, and at least one of the case body and the case cover is provided with a plurality of hollow protrusions for holding a central shaft of the gear so as to face the inside of the speed reducer. On both sides of at least one hollow protruding portion, a linear reinforcing rib is provided so as to extend in a direction of a stress applied to a central shaft of the held gear and in a direction opposite to the direction of the stress.

The present disclosure mainly focuses on the arrangement of the rib members in the gear case, and a general structure may be adopted for the brushless motor unit, the gear, and the like, and therefore, a detailed description of the structure of the brushless motor unit, the gear, and the like will be omitted hereinafter, and a structure related to the rib members inside the gear case of the present disclosure will be described with reference to fig. 1 to 5.

First embodiment

Fig. 1 shows a top view of a case cover 100 of a gear case of a first embodiment of the present disclosure, and fig. 2 shows a perspective view of the case cover 100 of the gear case of the first embodiment of the present disclosure.

The case cover 100 is provided with a plurality of hollow protrusions 110, 120, 130, 140 for holding the central shaft of the gear so as to face the inside of the speed reducer. In fig. 1-2, linear reinforcing ribs 131 are provided on both sides of the hollow protrusion 130. The direction in which the reinforcing rib 131 is provided is the direction in which the central shaft of the held gear receives stress and the direction opposite to the direction of the stress.

A method for determining the installation direction of the reinforcing rib 131 will be described below with reference to fig. 3.

Fig. 3 schematically illustrates the primary drive gear 220, a primary driven gear 231 engaged with the primary drive gear 220, a secondary drive gear 230 coaxially disposed with the primary driven gear 231, and a secondary driven gear 241 engaged with the secondary drive gear 230. A first shaft 320 is provided at the center of the primary driving gear 220, a second shaft 330 is provided at the center of the primary driven gear 231, and a third shaft 340 is provided at the center of the secondary driven gear 241. The first shaft 320, the second shaft 330, and the third shaft 340 are sometimes collectively referred to as the central shaft of the gear. Since the secondary drive gear 230 is disposed coaxially with the primary driven gear 231, a second shaft 330 is also disposed in the center of the secondary drive gear 230. Although not shown, the center shaft of the gear is disposed in the hollow protrusion on the inner side of the case cover. The number of gears is not limited thereto, and may be increased according to design requirements.

The primary drive gear is a relative concept, as long as it can mesh with an adjacent driven gear and transmit a driving force. The primary drive gear may be fixedly attached to the rotation shaft of the brushless motor unit to transmit the driving force from the brushless motor unit to rotate, or may be a transmission gear to transmit the driving force from the previous drive gear to rotate. The primary drive gear 220 in fig. 3 is a transfer gear, and a first shaft 320 provided at the center thereof is disposed in the hollow protrusion 120 shown in fig. 1-2. Accordingly, the second shaft 330 of fig. 3 is disposed in the hollow protrusion 130 of fig. 1-2, and the third shaft 340 of fig. 3 is disposed in the hollow protrusion 140 of fig. 1-2.

In fig. 3, the primary driving gear 220 has a number of teeth a and a modulus δ, the primary driven gear 231 has a number of teeth B and a modulus δ, the secondary driving gear 230 has a number of teeth B and a modulus γ, and the secondary driven gear 241 has a number of teeth c and a modulus γ. When the plurality of gears are seen in plan view along the direction of the first shaft 320, any one of the straight lines passing through the axis of the first shaft 320 and not passing through the axis of the second shaft 330 and the axis of the third shaft 340 is defined as a reference line L, an angle formed by the straight line passing through the axis of the first shaft 320 and the axis of the second shaft 330 and the reference line L is defined as α, an angle formed by the straight line passing through the axis of the second shaft 330 and the axis of the third shaft 340 and the reference line L is defined as β, and an angle formed by the direction of stress received by the second shaft 330 and the reference line L is defined as θ.

Further, assuming that the torque of the primary drive gear 220 is Ta, the force applied to the primary driven gear 231 in the normal direction is f, the torque of the secondary drive gear 230 is Tb, and the force applied to the secondary driven gear 241 (i.e., the secondary drive gear 230) in the normal direction is g, there are:

Substituting the torque corresponding to deceleration, the value of g can be expressed as follows:

and f and g are respectively decomposed into X, Y components to obtain:

Since the resultant force of f and g (stress applied to the second shaft 330) forms an angle θ with the reference line L, the X, Y components are synthesized, respectively, to obtain:

θ has the following relation with xθ and yθ:

therefore, the angle θ between the direction of the stress applied to the second shaft 330 and the reference line is calculated:

that is, the reinforcing rib 131 is disposed at an angle θ to the reference line,

As shown in fig. 3, the reinforcing ribs 131 are disposed in the direction indicated by the thick broken line.

By the above formula, the direction of the stress applied to each center shaft can be accurately calculated by only the reduction ratio and the arrangement of each gear.

Accordingly, the present disclosure can simply and accurately arrange the reinforcing rib in the direction in which the second shaft and the hollow protruding portion are subjected to stress, and can effectively use the reinforcing rib to prevent deformation of the hollow protruding portion.

Further, since the linear reinforcing ribs are provided on both sides of the hollow protruding portion so as to extend in the direction of the stress applied to the central shaft and in the direction opposite to the direction of the stress, deformation of the hollow protruding portion can be prevented not only when the motor rotates forward but also when the motor rotates backward.

Since the reinforcing ribs can be accurately arranged in the stress direction, the deformation of the hollow protruding portion at the time of forward rotation and the time of reverse rotation of the motor can be effectively prevented by only two reinforcing ribs provided on both sides of the hollow protruding portion, and the number of ribs to be provided can be reduced, thereby realizing weight reduction of the gear box.

In addition, fig. 1 to 2 only show the case where hollow protrusions and reinforcing ribs are provided on the cover. Preferably, the hollow protrusions and the reinforcing ribs are provided in both the case body and the case cover of the gear case, and in the assembled state, the hollow protrusions provided in the case body and the hollow protrusions provided in the case cover are disposed in one-to-one correspondence, and the reinforcing ribs provided in the case body and the reinforcing ribs provided in the case cover are disposed in one-to-one correspondence. In this way, the strength of the gearbox can be further increased.

Fig. 3 shows a case where reinforcing ribs 131 are provided on both sides of the hollow protrusion 130 holding the second shaft 330. However, the present invention is not limited thereto, and reinforcing ribs may be provided on both sides of the other hollow protrusions according to actual strength requirements.

In addition, it is preferable that the case body and the case cover are injection-molded pieces, and the reinforcing ribs provided on both sides of the hollow protruding portion are integrally formed with the hollow protruding portion by injection molding.

Second embodiment

Fig. 4 shows a top view of a case cover 200 of a gear case of a second embodiment of the present disclosure, and fig. 5 shows a perspective view of the case cover 200 of the gear case of the second embodiment of the present disclosure.

In the present embodiment, an auxiliary rib 132 is provided on at least one of the case and the cover so as to face the inside of the speed reducer. The arrangement of other portions in this embodiment is substantially the same as that in the first embodiment, and thus detailed description thereof is omitted. The auxiliary ribs in the present embodiment are provided to prevent deformation of the case and/or the cover during injection molding, and the shape and position thereof are not particularly limited.

Preferably, the strength of the reinforcing rib 131 is greater than that of the auxiliary rib 132. In this way, the hollow protrusion portion subjected to stress can be effectively supported by the reinforcing rib having a greater strength.

The cover 200 of the gearbox shown in fig. 4-5 is an injection molded part with the body formed integrally with the hollow protrusions, reinforcing ribs and auxiliary ribs. As shown in fig. 4 to 5, one end of the reinforcing rib 131 is connected to the hollow protrusion 130, and the other end of the reinforcing rib 131 is connected to the auxiliary rib 132.

As an example, two or more rib members, which are reinforcing ribs or auxiliary ribs, are connected between the two hollow protrusions. Accordingly, the two hollow protrusions are not connected by only one linear rib member, and deformation of the hollow protrusions can be further prevented.

Further, although not shown, a circuit board having printed wiring and a plurality of electronic components protruding from the surface is housed in the gear case, and the plurality of electronic components are housed in gaps formed between the rib members. Thus, the multi-stage reduction gear can be further miniaturized.

As described above, the multistage speed reducer of the present disclosure can achieve both downsizing, weight saving and rigidity of the gear box.

Those skilled in the art will appreciate that the features recited in the various embodiments of the disclosure and/or in the claims may be provided in a variety of combinations and/or combinations, even if such combinations or combinations are not explicitly recited in the disclosure. In particular, the features recited in the various embodiments of the present disclosure and/or the claims may be variously combined and/or combined without departing from the spirit and teachings of the present disclosure. All such combinations and/or combinations fall within the scope of the present disclosure.

The embodiments of the present disclosure are described above. These examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the embodiments cannot be used advantageously in combination. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be made by those skilled in the art without departing from the scope of the disclosure, and such alternatives and modifications are intended to fall within the scope of the disclosure.

Claims

1. A multi-stage speed reducer is provided with:

A brushless motor unit;

A plurality of gears driven to rotate by the brushless motor unit; and

A gear case housing the brushless motor unit and the plurality of gears,

It is characterized in that the method comprises the steps of,

The plurality of gears includes:

a primary drive gear;

a primary driven gear engaged with the primary drive gear;

A second-stage drive gear coaxially arranged with the first-stage driven gear; and

A secondary driven gear engaged with the secondary driving gear,

A central shaft is respectively arranged at the centers of the plurality of gears,

The central shaft includes a first shaft disposed at the center of the primary driving gear, a second shaft disposed at the centers of the primary driven gear and the secondary driving gear, and a third shaft disposed at the center of the secondary driven gear,

The gear box comprises a box body and a box cover,

At least one of the case and the case cover is provided with a plurality of hollow protrusions for holding the central shaft of the gear so as to face the inside of the speed reducer,

On both sides of at least one of the hollow protrusions, a linear reinforcing rib is provided so as to extend in a direction of a stress applied to a central axis of the gear and in a direction opposite to the direction of the stress.

2. The multi-stage reduction gear according to claim 1, wherein,

The hollow protruding part and the reinforcing rib are arranged on the box body and the box cover,

In the assembled state, the hollow protrusions provided on the case body are disposed in one-to-one correspondence with the hollow protrusions provided on the case cover, and the reinforcing ribs provided on the case body are disposed in one-to-one correspondence with the reinforcing ribs provided on the case cover.

3. The multi-stage reduction gear according to claim 1, wherein,

The reinforcing ribs are provided on both sides of a hollow protruding portion that holds the second shaft.

4. The multi-stage reduction gear according to claim 3, wherein,

The number of teeth of the primary driving gear is a, the modulus is delta,

The number of teeth of the primary driven gear is B, the modulus is delta,

The number of teeth of the secondary driving gear is b, the modulus is gamma,

The number of teeth of the secondary driven gear is c, the modulus is gamma,

When a plurality of the gears are seen in plan view in the direction of the first axis,

Taking any straight line passing through the axle center of the first shaft and not passing through the axle center of the second shaft and the axle center of the third shaft as a datum line,

An angle formed by a straight line passing through the axes of the first shaft and the second shaft and the reference line is alpha,

An angle formed by a straight line passing through the axes of the second shaft and the third shaft and the reference line is beta,

The reinforcing rib is disposed at an angle theta with respect to the reference line,

5. The multi-stage reduction gear according to claim 1, wherein,

The case body and the case cover are injection-molded parts, and the reinforcing ribs provided on both sides of the hollow protruding portion are integrally formed with the hollow protruding portion by injection molding.

6. The multi-stage reduction gear according to claim 5, wherein,

Auxiliary ribs are also provided on the case body and the case cover so as to face the inside of the speed reducer.

7. The multi-stage reduction gear according to claim 6, wherein,

The strength of the reinforcing rib is greater than that of the auxiliary rib.

8. The multi-stage reduction gear according to claim 6, wherein,

One end of the reinforcing rib is connected with the hollow protruding part, and the other end of the reinforcing rib is connected with the auxiliary rib.

9. The multi-stage reduction gear according to claim 6, wherein,

More than two rib members are connected between the two hollow protruding parts, and the rib members are the reinforcing ribs or the auxiliary ribs.

10. The multi-stage reduction gear according to claim 9, wherein,

A circuit board is also accommodated in the gear box,

The circuit board has printed wiring and a plurality of electronic components protruding from a surface,

The plurality of electronic components are accommodated in gaps formed between the rib members.