JP3100264B2 - Cartesian gearbox with motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor-equipped orthogonal gear reducer suitable for use in logistics equipment and the like, particularly for applications such as conveyors and unmanned traveling vehicles, and for use in industrial robots and the like.

[0002]

2. Description of the Related Art In recent years, in the market of logistics equipment, especially conveyors and the like, the need for a motor-equipped orthogonal gear reducer having a motor and having a motor shaft and an output shaft orthogonal to each other is increasing.

The reason why "with motor" is required is as follows.

That is, for example, in a distribution system including a plurality of conveyors, it is efficient to operate only necessary parts only when necessary. In this case, it is advantageous if the drive of each conveyor is independent. or,
It is often the case that the arrangement of individual conveyors is changed in order to change the transport path, but in this case also, it is advantageous if the driving of each conveyor is independent.

On the other hand, the reason why the "orthogonal gear reducer" is required is as follows.

That is, in general, the maximum dimension (longitudinal dimension) of a motored gear reducer is in the axial direction of the motor. Therefore, in order to improve the space when the gear reducer is mounted, it is best to arrange the direction of the maximum dimension (the direction of the motor shaft) in parallel with the conveyor. However, to drive the conveyor shaft, the output shaft of the gear reducer must be parallel to the conveyor shaft. Therefore, the output shaft of the gear reducer needs to be orthogonal to the motor shaft.

The present applicant has already filed Japanese Patent Application No. 62-28304.
4 (JP-B-2-53656) proposes a motor-equipped orthogonal gear reducer that satisfies such a demand. 6 and 7 show this reduction gear.

In this orthogonal gear reducer with a motor, a first stage is a hypoid gear set 20 comprising a hypoid pinion 4 and a hypoid gear 5, and the second and subsequent stages are parallel shaft gears 2.
It is composed of one combination.

The hypoid gear set 20 includes a motor shaft 3
And a hypoid gear 5 that is attached to a shaft whose axis is shifted from the motor shaft 3 by e1 and is orthogonal to the shaft, and meshes with the hypoid pinion 4.

[0010] The parallel shaft gear 21 is a hypoid gear 5.
A second-stage pinion 7 integrated and coaxial with the
A second-stage gear 8 meshing with the second-stage pinion 7, a third-stage pinion 10 integrally and coaxially arranged with the second-stage gear 8,
A third-stage gear 11 that meshes with the third-stage pinion 10;
It comprises a stage gear 11 and an output shaft 12 that rotates integrally. Therefore, the reduction ratio can be changed by changing the combination of the parallel shaft gears 21.

For this reason, the sub-series in which the fitting dimensions to the counterpart machine determined by the dimensions of the output shaft 12 and the gear box 2 are divided into several types from small to large in accordance with the demands of the market. Subseries afterwards "frame number"
) Is prepared in advance, and several types of speed reduction ratios are sequenced in advance with the same frame number to prepare the entire series as a series, thereby making it possible to respond to various users.

The motor shaft 3 has a gear box side bearing (motor shaft load side bearing) 13 in the motor joint cover 14 and a counter gear box side bearing (motor shaft counter load side bearing) in the motor joint cover 23 on the opposite gear box side. And 22) are supported by a pair of bearings.

The load generated by the engagement between the hypoid pinion 4 and the hypoid gear 5 acts on the motor shaft 3 and is held by the pair of bearings 13 and 22. Here, the bearing load by the hypoid gear set 20 is different from that in which the load by the parallel shaft gear 21 in the second and subsequent stages is almost only a radial load (radial load).
The axial component (thrust load) of the motor shaft 3 is also large,
Moreover, there is a feature that the load direction of the thrust load is reversed depending on the rotation direction of the motor shaft 3.

FIG. 8 schematically shows the relationship between the direction of the thrust load and the holding in a conventionally known motor structure.

The thrust load varies depending on the torsional direction of the hypoid pinion 4, but in the case of left-handed twist, the direction of FA, ie, the motor shaft 3 is pushed in the direction of the motor in the case of clockwise rotation viewed from the counter gear box side of the motor. A load (this is called a motor-direction thrust load for convenience) occurs, and in the case of counterclockwise rotation, the direction of FB, that is, a load that pulls the motor shaft in the gearbox direction (this is called a gearbox-direction thrust load for convenience). Occurs. The reverse is true if the hypoid pinion 4 is twisted right.

Among the loads acting on the motor shaft 3, the radial load is mostly held by the gear box-side bearing 13 due to the bearing span, and the difference due to the rotation direction can be almost ignored.

However, with regard to the thrust load, the bearing to be held differs depending on the direction of rotation. The motor-direction thrust load FA is mainly held by the counter gear box side bearing 22, the counter gear box side motor joining cover 23, and the step portion 28 of the motor shaft. The ratio between the thrust load and the radial load on the anti-gear box side bearing 22 in this load direction is about 10 to 1 in the known example, which is almost the thrust load. Therefore, the anti-gear box side bearing 22 needs a structure or a size capable of holding a considerably large thrust load.

On the other hand, the gear box direction thrust load FB is held by the flange 27 of the motor shaft 3, the gear box side bearing 13, and the motor joint cover 14. The ratio between the thrust load and the radial load on the gearbox-side bearing 13 in this load direction is about 1: 1 in the known example.

As described above, it is a feature of the conventional structure that the bearing holding the thrust load varies depending on the rotation direction.

[0020]

However, such a conventional orthogonal gear reducer with a motor has a problem that it cannot sufficiently cope with the diversification of motors and their usages accompanying the recent rationalization of production systems. It has become noticeable. That is, it is difficult to provide a series of speed reducers that can meet a wide range of needs of the user at low cost or with a short delivery date. Is becoming difficult to provide in such a series.

Hereinafter, this situation will be described in some detail.

In the field of a distribution system in which this type of speed reducer is frequently used, as described above, it is efficient to operate only a necessary portion of a distribution system including a plurality of conveyors only when necessary. For this reason, the drive of each conveyor has become independent.

However, the orthogonal gear reducer with a motor used for a conveyor or the like here merely constitutes a part of a partner machine (a conveyor or the like), and the partner machine or the like also constitutes a part of the entire distribution system. It merely constitutes a part. Therefore, in relation to the entire distribution system, it has been required that the orthogonal gear reducer with a motor be housed more compactly and that the necessary functions of the conveyor be satisfied by combination with an optimal motor.

The function of the conveyor is simply sufficient if it has a function of simply moving the conveyed object. For example, the control of the conveying speed and the stop control to a fixed position are performed in order to identify and arrange the conveyed object. What is required is required (for convenience, the former is called a general-purpose conveyor, and the latter is called a control conveyor).

In general, a combination of a cage-type induction motor and a gear reducer is used for a general-purpose conveyor, and a combination of a servomotor and a gear reducer is used for a control conveyor. A reduction gear combined with a servomotor has a small angle backlash, and a low-angle backlash type reduction gear suitable for stop control at a fixed position has been required.

Here, the angle backlash refers to play or play that occurs when the motor moves from normal rotation to reverse rotation. In other words, it indicates how much the input shaft should rotate in reverse, and the output shaft should follow the reverse. The amount (angle) by which one shaft (low-speed side or high-speed side) can be moved while the other is stopped. ) Can also be defined.

The existence of such angle backlash naturally lowers the accuracy when the transmission mechanism is used as a control device with forward / reverse rotation, and in view of the pure mechanical durability of the transmission device itself. However, it is not preferable because a larger impact is likely to occur. Although it is said that the above-described orthogonal gear reducer with motor can reduce the angular backlash relatively in terms of structure, there is still an angle backlash that cannot be ignored in view of today's high needs.

However, when viewed from the motor side, the situation of reducing the angle backlash on the reduction gear side is, for example, only one of the application examples of the servo motor, and the motor needs to be adapted to one application example. Changing the basic configuration undesirably leads to higher costs and longer delivery times. That is, when viewed from the motor side, it is not necessary to change the configuration of the gear box side each time depending on whether the gear box side is a low backlash type or a general-purpose type. However, conventionally, it has been extremely difficult to construct a low backlash type motorized orthogonal gear reducer regardless of the motor side.

This is related to the fact that it was difficult to reduce the angle backlash itself in the conventional orthogonal gear reducer with motor because of its structure. Since this is related to the effect of the present invention, this will be described in some detail.

In this type of reduction gear, the hypoid pinion 4 is used in order to make the reduction gear as a whole compact.
Is formed integrally with the motor shaft 3 at the tip of the motor shaft 3. That is, the motor shaft 3 is required to function not only as a central axis of the motor but also as a hypoid pinion.
Therefore, the bearings 13 and 22 that support the same need to retain the load as the hypoid pinion, and also require the assembly accuracy of the hypoid pinion in the axial direction while the thrust load acting on the shaft is large. It is necessary to have the rigidity of the whole set 20.

However, the motor shaft 3 originally has a considerably long overall length due to the function of the center shaft of the motor.
It has been extremely difficult to satisfactorily realize the maintenance of rigidity and the like in the concept of a series.

For example, taking the speed reducer shown in FIGS. 6 to 8 as an example, if this problem is solved in consideration of this single speed reducer, only the motor shaft 3 It is sufficient to select the gear box side bearing 13 and the counter gear box side bearing 22 according to the required load capacity and rigidity, and to increase the bearing size accordingly.

However, the motor is the motor frame 2
4. The brake unit and the rotation detector unit are provided outside the counter gear box side cover 23 while sharing the basic components such as the stator core 25, the rotor core 26, and the counter gear box side bearing 22. Therefore, a motor with a brake and a motor with a rotation detector must be serialized according to the needs of the user.

In the presence of such a design concept of series as a motor group, the anti-gear box bearing 22 of the motor shaft is required because of the necessity for the function as a hypoid gear set.
If the dimensions are simply increased, it becomes difficult to use the brake unit or the rotation detector unit as it is or to disuse it, resulting in a lot of waste as a whole series, cost, weight, and delivery time. It is extremely difficult to deal with the situation, and in some cases, the correspondence itself may not be possible.

On the other hand, the conventional structure also has various problems regarding the reduction of the backlash in the gear transmission mechanism.

Referring to FIGS. 7 and 8, the accuracy of the assembly dimension MD of the hypoid pinion 4 and the hypoid gear 5 is basically determined when machining is performed on a gear cutting machine generally used as a machining machine for this type of hypoid gear set. Is determined by the reference size. As a matter of course, by accurately managing the dimension MD, the gap between the hypoid gear sets can be reduced (without seizure or the like), and backlash can be reduced. In order to accurately control the MD dimensions, it is necessary to have the machining precision of the A dimension of the gear box and the precision of the B dimension of the motor after assembly.

By the way, a servo motor which requires a gear reducer having a small angle backlash has a motor frame 24 made of an extruded aluminum material or an aluminum die-cast material because of its light weight, heat dissipation and aesthetic appearance. Often produced in.

On the other hand, the motor shaft 3 integrally formed with the hypoid pinion 4 at one end is generally made of a carburized and quenched and tempered alloy steel because the hypoid pinion portion requires high hardness. . In this case, the coefficient of linear expansion of the motor frame 24 is about twice as large as the coefficient of linear expansion of the motor shaft 3. In order to ensure starting in the cold season, even a small motor having a length of the motor frame 24 of about 150 mm is used. It is necessary to secure the axial gap σA in FIG. As a result, even if this gap is set to a minimum, the axial gap .sigma.A increases to about 0.2 to 0.3 mm with a rise in temperature in a normal use state of the motor. Therefore, the B dimension of the motor changes remarkably depending on the rotation direction, and the change in the gap becomes an angle backlash and becomes apparent.

That is, in a conventionally known motor structure,
Motor frame 24 (because the motor shaft is originally long)
The use of a material having a larger coefficient of linear expansion than a motor shaft, such as an aluminum extruded material or an aluminum die-cast material, has a problem that it is very difficult to reduce the angle backlash.

The present invention has been made in view of such a conventional problem, and a series of motor-equipped orthogonal gear reducers of various modes required by a user in accordance with diversification of a distribution system. Is provided at low cost and in a user-friendly manner, and in this series,
It is an object of the present invention to provide a motor-equipped orthogonal gear reducer capable of incorporating a group with reduced angle backlash (without depending on the material or the like) without any trouble, and to solve the above-mentioned various problems at once.

[0041]

According to the present invention, there is provided a motor having a motor shaft supported by a pair of bearings, a gear box having an output shaft arranged orthogonally to the motor shaft, and wherein the gear is provided. A motor having a built-in hypoid gear set including a hypoid pinion formed integrally with the motor shaft and a hypoid gear mounted on a shaft that is orthogonal to the motor shaft so as to be displaced from the motor shaft and meshed with the hypoid pinion. The orthogonal cross gear reducer with one of the motor shafts.
Of the pair of bearings, the gearbox bearing is replaced by the gearbox motor connection.
When fixed axially to both the bar and the motor shaft,
In addition, the anti-gear box side bearing and the anti-gear box side motor joint cover
Are arranged so that a gap can be formed between them , and the axial component force generated by the engagement of the hypoid pinion and the hypoid gear in the axial direction of the motor shaft is supported irrespective of the rotation direction of the motor shaft. The above-mentioned problem has been solved by adopting a structure in which only the bearing portion on the gear box side of the pair of bearings is received.

[0042]

According to the present invention, regardless of the rotation direction of the motor shaft, the axial component (thrust load) of the motor shaft caused by the engagement of the hypoid pinion and the hypoid gear is determined.
All are received (held) only by the gear box side bearing part
It was configured as follows. As a result, it is not necessary to consider the thrust load for the bearing on the side opposite to the gear box of the motor, and it is sufficient to use a small bearing. This should be shared for all orthogonal gear units with motors. Becomes easier. Therefore, a brake system, a rotation detector, and the like can be incorporated into this portion without any trouble.

Further, even if the motor shaft is long and the material is different from the material of the motor frame, the difference in the coefficient of linear expansion can be easily absorbed on the side opposite to the gear box. Thus, the precision of the assembling dimensions (accuracy of the dimension MD) of the hypoid gear set in the gear box side bearing to the gear box can be drastically improved.

As a result, it is possible to reduce the gap between the gears at the time of assembly without causing seizure or the like, and it is possible to easily combine a gear box having a low angle backlash with a servomotor or the like. become able to.

In order to specifically realize the holding structure, for example, a flange portion is integrally formed near a gear box side bearing of the motor shaft, and a positioning portion is formed near a tip of the motor shaft. A collar can be fitted, the gearbox side bearing is axially positioned with respect to the motor shaft by the flange portion and the collar, and a bearing fixing plate is disposed between the motor rotor and the gearbox side bearing. At the same time, it is preferable that the gear box-side bearing is fixed to the motor joint cover and the motor shaft via the bearing fixing plate.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment in which the structure according to the present invention is applied to a leg-mounted orthogonal gear reducer with a motor. FIG. 2 is an axial sectional view showing the arrangement of the gear train of FIG. 1, and FIG. 3 is a detailed view of a motor portion in the above embodiment.

In the gear box 102, the hypoid pinion 10 formed integrally with the tip of the motor shaft 103 is provided.
4. a hypoid gear 105 meshing with the hypoid pinion 104; a second stage pinion 107 integrally and coaxially arranged with the hypoid gear 105; a second stage gear 108 meshing with the second stage pinion 107; 1
An output shaft 112 that rotates integrally with the output shaft 08 is provided.

The basic structure in the gear box 102 is different from the structure shown in FIGS. 6 and 7 in that it has a three-stage speed reduction structure, but is simply omitted in two stages. There is no particular difference in the basic configuration itself from the conventional design concept. Therefore, detailed description is omitted.

Hereinafter, the portion according to the present invention of this embodiment will be described in detail with reference to an enlarged view of the motor portion of FIG.

In the vicinity of the gear box-side bearing 113 of the motor shaft 103, a flange 127 is integrally formed.
The hypoid pinion 104 is formed integrally with the motor shaft 103, and the finished dimensions of the gear as a gear are processed and managed based on the flange 127.

The motor shaft 103 has a gear box side bearing 113.
Is positioned between the end face of the flange portion 127 and the end face of the collar 130, so that the gear box-side bearing 113 extends in the axial direction with respect to the motor shaft 103. Is determined. The collar 130 is specifically tightly fitted to the motor shaft 103 by shrink fitting or the like.

In the figure, reference numeral 119 denotes an oil seal, and 131 denotes a shaking plate. The shaking plate 131 reinforces the sealing function of the oil seal 119.

The retaining ring 132 reinforces the fixing force of the collar 130 to the motor shaft 103, and may not be provided in some cases.

The motor shaft 103 and the gearbox-side bearing 113 assembled to the motor shaft 103 are fixed to the motor joining cover 114 by a bearing cover (bearing fixing plate) 128 and a bearing cover mounting bolt 130.

The motor frame 124 is made of an extruded aluminum material or an aluminum die cast material because it is easy to reduce the weight, has good heat dissipation, and has an aesthetic appearance. On the other hand, the motor shaft 103 is made of a carburized, quenched and tempered alloy steel in order to secure the hardness of the hypoid pinion portion.

The motor frame 124 and the motor shaft 10
In particular, in the cold season, the motor shaft 1
03 is prevented from being locked by the motor joint cover 123 on the opposite side of the gearbox of the motor shaft and the bearing 122 on the opposite side of the gearbox.
And is provided between them. As a result, the difference in the coefficient of linear expansion caused by the different materials of the motor frame 124 and the motor shaft 103 can be absorbed in the gap δA without any trouble (without increasing the angle backlash).

Also, regardless of the rotation direction of the motor shaft 103, the motor shaft 1 generated by the hypoid gear set
Both the axial component forces FA and FB of the gear box-side bearing 11
3 so that the motor joint cover 1
The dimension B of the mounting surface 116 of the No. 14 and the flange portion 127 which is also the reference surface at the time of gear cutting of the hypoid pinion 104 is as follows:
It is always kept constant within the range of the internal clearance of the gear box-side bearing 113. Accordingly, the thrust loads FA and FB do not act on the anti-gear box side bearing 122 at all, and therefore, as will be described later, there is no hindrance to providing a brake unit or other members for rotation control on the outside thereof. Such a small common part can be used.

The fact that the dimension B can be made constant means that the MD dimension (described with reference to FIG. 7) as a hypoid gear set can be managed with high accuracy. As a result, there is no fear that the gap is too close due to the rotation of the hypoid pinion 104, so that the gap at the time of assembling the hypoid gear set can be set to the minimum necessary. This not only allows a low-backlash type gear box to be easily manufactured, but also enables a low-backlash type gear box manufactured in this way, and a gear box that is not particularly designed to have a low-backlash mode. Means that they can be selected and combined independently of the structure on the motor side, and the series configuration is greatly simplified.

Regarding the second and subsequent parallel shaft gears, since the rotation speed of the motor shaft is reduced by the hypoid gear set, even if the gap between the gears is reduced, the problem of seizure and noise relatively occurs. It is difficult to close the gap. That is, whether or not a gear box of a low backlash type can be manufactured depends on how the gap can be reduced in the hypoid gear set portion. By adopting the above structure, the gap in this portion is reduced. The reduction can be easily realized (without causing a risk of seizure or the like).

In FIG. 4, the brake unit 140 is provided outside the motor joint cover 123 on the side opposite to the gear box in the embodiment shown in FIGS. An example using a motor is shown.

FIG. 5 shows an anti-gear box side bearing 1 when the motor shown in FIGS. 1 to 3 is replaced with a servomotor and a brake unit 255 with a rotation detector is attached.
An enlarged view around 22 is shown.

Although not shown in both figures, the hypoid gear set and the parallel shaft gear reducer employ a low backlash type structure. As described above, since the anti-gear box side bearing 122 hardly needs to receive the thrust bearing, it can be downsized, and various control units can be easily attached to the outer portion. Things.

In FIG. 5, reference numeral 203 denotes a motor shaft, 223 denotes a motor joint cover, 250 denotes a brake unit, 251 denotes a rotation detector mounting plate, 252 denotes a rotation detector,
253 is a rotation detector cover, and 254 is an electric fan.

[0065]

As described above, according to the present invention, a series of motor-equipped orthogonal gear reducers of various modes required by the user in accordance with the diversification of the distribution system can be manufactured at low cost. Provided in a user-friendly manner,
Moreover, an excellent effect is obtained in which a group with reduced angle backlash (without depending on the material or the like) can be incorporated into the series without any trouble (without increasing the cost or weight).

[Brief description of the drawings]

FIG. 1 is a front sectional view in the axial direction showing an embodiment (showing a developed gear train) of a motorized orthogonal gear reducer to which the present invention is applied.

FIG. 2 is an axial cross-sectional view (showing the arrangement of gear trains) of the orthogonal gear drive with motor shown in FIG. 1;

FIG. 3 is an enlarged view of a motor portion of the orthogonal gear reducer with a motor.

FIG. 4 is a sectional front view in the axial direction showing an example in which the motor of FIG. 1 is replaced by a motor with a brake provided with a brake unit outside the motor joint cover on the side opposite to the gear box.

FIG. 5 is an axial front sectional view showing an example in which a servo motor is used as the motor shown in FIGS. 1 to 3 and a brake unit with a rotation detector is attached thereto.

FIG. 6 is a sectional front view in the axial direction of a conventional orthogonal gear reducer with a motor (expanded gear train).

FIG. 7 is an axial cross-sectional view of the orthogonal gear reducer with a motor shown in FIG. 6;

FIG. 8 is an enlarged view of a motor portion of the orthogonal gear reducer with a motor shown in FIGS. 6 and 7;

[Explanation of symbols]

 103: Motor shaft 104: Hypoid pinion 105: Hypoid gear 113: Gear box side bearing 114: Motor joint cover 122: Counter gear box side bearing 123: Motor joint cover 124: Motor frame 127: Flange part 128: Bearing cover (bearing fixing plate) ) 130: Collar (positioning material) 140: Brake unit 225: Brake unit with rotation detector

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuo Sakimoto 6-1, Asahimachi, Obu-shi, Aichi Pref. Sumitomo Heavy Industries, Ltd. Nagoya Works Japanese Patent Publication No. 2-53656 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 57/02 521

Claims (3)

(57) [Claims] 1. A motor having a motor shaft supported by a pair of bearings, and a gear box having an output shaft arranged orthogonally to the motor shaft, wherein the motor shaft is provided in the gear box. a hypoid pinion integrally formed in the motor shaft and mounted on the shaft which is perpendicular to shifting the axis the hypoid pinion and a built-in hypoid gear set comprising a meshing hypoid orthogonal gear reducer with a motor, wherein Of the pair of bearings on the motor shaft, the gearbox side bearing
Shaft direction for both motor joint cover and motor shaft on the box side
And the anti-gear box side bearing and the anti-gear box side motor joint cover
And a pair of components that support the motor shaft regardless of the rotation direction of the motor shaft, regardless of the rotational direction of the motor shaft, and dispose an axial component force generated by the engagement of the hypoid pinion and the hypoid gear. A orthogonal gear reducer with a motor, characterized in that the structure is such that only the bearing part on the gear box side is received among the above bearings. 2. A motor according to claim 1, wherein a flange portion is integrally formed near a gear box side bearing of said motor shaft, and a positioning collar can be fitted near a front end of said motor shaft. With the collar, the gear box side bearing is axially positioned with respect to the motor shaft, and a bearing fixing plate is arranged between the rotor of the motor and the gear box side bearing, and this is fixed to the motor joint cover. The gearbox-side bearing is fixed to the joint cover of the motor and the motor shaft via the bearing fixing plate. 3. The orthogonal gear reducer with a motor according to claim 1, wherein the frame of the motor is made of a material having a larger linear expansion coefficient than the motor shaft.