JP7065572B2 - Wheel drive and wheel drive series - Google Patents

Description

The present invention relates to a series of wheel drives and wheel drives.

Conventionally, as a wheel drive device for driving wheels of a transport carriage or the like, a wheel drive device having a deceleration mechanism incorporated therein has been known. For example, Patent Document 1 discloses a wheel drive device including a rotating body whose rotation is transmitted from a deceleration mechanism and a tire fitted on the outer peripheral side of the rotating body.

Japanese Unexamined Patent Publication No. 2012-71810

The wheel drive device of Patent Document 1 employs a structure in which a stepped fitting surface parallel to the axial direction is provided on the outer peripheral surface of the rotating body, and the tire wheel is fitted on the outside of the fitting surface. As a result of the study by the present inventor, it has been found that in this structure, fretting wear is likely to occur between the fitting surface of the rotating body and the wheel. Fretting wear causes problems, so countermeasures are desired.

One aspect of the present invention has been made in view of these circumstances, one of which is to provide a wheel drive device capable of combating fretting wear.

One aspect of the present invention relates to a wheel drive device, which comprises a deceleration mechanism for decelerating rotation transmitted from a drive source, a tubular output member for which rotation decelerated by the deceleration mechanism is transmitted, and external fitting to the output member. A wheel drive device including a baseband to be formed and a tire attached to the baseband, wherein tapered surfaces are provided on an outer peripheral surface of the output member and an inner peripheral surface of the baseband, and the baseband is provided. Is externally fitted to the output member by tightening and fitting in a state where the tapered surfaces are in contact with the output member.

According to the present invention, it is possible to provide a wheel drive device capable of taking measures against fretting wear.

It is a front sectional view which shows the wheel drive device of this embodiment. It is an enlarged view of a part of FIG. It is a front sectional view of the 2nd wheel drive device of this embodiment. FIG. 4A is an enlarged view of a part of the first wheel drive device, and FIG. 4B is an enlarged view of a part of the second wheel drive device.

Hereinafter, in the embodiments and modifications, the same components are designated by the same reference numerals, and duplicate description will be omitted. Further, in each drawing, for convenience of explanation, some of the constituent elements are appropriately omitted, and the dimensions of the constituent elements are appropriately enlarged or reduced.

First, the background of the idea of the wheel drive device of the present embodiment will be described. The wheel drive device of the present embodiment includes a cylindrical output member to which the rotation of the deceleration mechanism is transmitted, a baseband externally fitted to the output member, and a tire attached to the baseband. In this type of wheel drive device, if fitting wear occurs on the contact surface between the output member and the baseband, the wear debris causes contamination of the surrounding environment. This becomes a problem when the wheel drive device is used in an environment such as a clean room where cleanliness is required.

Further, in this type of wheel drive device, since the tire wears over time, the baseband may be removed from the output member for the purpose of replacing the tire. In this case, if fitting wear occurs on the contact surface between the output member and the baseband, the output member and the baseband are fixed by the wear powder, and the baseband may not be removable from the output member.

As described above, the fitting wear generated between the output member and the baseband causes a defect. As a countermeasure, in the wheel drive device of the present embodiment, the baseband is externally fitted to the output member by tightening and fitting. As a result, even when the baseband or the output member vibrates slightly, the contact surfaces of the two can be maintained in close contact with each other. Therefore, the relative displacement of the contact surface due to this slight vibration can be suppressed, and the occurrence of fretting wear due to the relative displacement can be prevented.

Further, in the wheel drive device of the present embodiment, the baseband and the output member are provided with tapered surfaces, and the baseband is externally fitted to the output member in a state where the tapered surfaces are in contact with each other. As a result, it is possible to realize a tight fit with a sufficient tightening margin while improving the assembling property of the baseband to the output member, and it is possible to effectively take measures against fretting wear. Hereinafter, the details of this wheel drive device will be described.

FIG. 1 is a front sectional view showing the wheel drive device 10 of the present embodiment. The wheel drive device 10 of the present embodiment is attached to the vehicle body 12 of the transport carriage and is used for driving the tires 28 of the transport carriage. The transport carriage of the present embodiment is a tracked carriage, and the tire 28 of the present embodiment travels on the traveling surface 16a of the rail 16 laid on the floor surface. Hereinafter, the direction along the rotation center line La of the tire 28 is referred to as the axial direction X of the wheel drive device 10. Further, the circumferential direction and the radial direction of the circle centered on the rotation center line La are simply referred to as "circumferential direction" and "diameter direction".

The wheel drive device 10 mainly includes a reduction mechanism 18, carriers 20, 22, an output member 24, a baseband 26, and a tire 28.

The deceleration mechanism 18 can decelerate the rotation transmitted from the drive source. The drive source in the present embodiment is a motor, but the drive source is not limited to this, and a gear motor, an engine, or the like in which the motor and the reduction gear are integrated may be used. The deceleration mechanism 18 of the present embodiment is an eccentric swing type deceleration mechanism. The reduction mechanism 18 mainly has an input shaft 30, an eccentric body 32, an external gear 34, an eccentric bearing 36, and an internal gear 38.

An output shaft 40 of a drive source protruding outward in the vehicle width direction from the vehicle body 12 is connected to the input shaft 30, and rotation output from the output shaft 40 is input.

The eccentric body 32 is provided so as to be rotatable integrally with the input shaft 30. A plurality of eccentric bodies 32 are provided at intervals in the axial direction X.

The external gear 34 is individually provided corresponding to each of the plurality of eccentric bodies 32. The external gear 34 is supported by the corresponding eccentric body 32 via the eccentric body bearing 36. The external tooth gear 34 is swung by the corresponding eccentric body 32 so that its axis rotates around the rotation center line La.

An external gear 34 is internally meshed with the internal gear 38. The internal gear 38 of the present embodiment has a plurality of outer pins 38a supported on the inner peripheral portion of the output member 24, and a plurality of outer rollers 38b rotatably supported by each of the plurality of outer pins 38a. .. Each of the plurality of outer rollers 38b constitutes the internal teeth of the internal gear 38. The number of internal teeth of the internal gear 38 (the number of external rollers 38b) is one more than the number of external teeth of the external gear 34 in the present embodiment.

The carriers 20 and 22 include an inner carrier 20 arranged on the vehicle body side of the external gear 34 and an outer carrier 22 arranged on the anti-vehicle body side of the external gear 34. In the present specification, the vehicle body side means the vehicle body 12 side in the axial direction X, and the anti-vehicle body side means the opposite side of the vehicle body 12 in the axial direction X.

Through holes 42 are formed in the carriers 20 and 22 so as to penetrate the central portion in the radial direction. An input shaft bearing 44 is arranged on the inner peripheral side of the through hole 42, and the carriers 20 and 22 rotatably support the input shaft 30 via the input shaft bearing 44. The input shaft bearing 44 of this embodiment is a rolling bearing such as a ball bearing.

The output member 24 has a cylindrical shape as a whole and is made of a metal such as a steel material. A deceleration mechanism 18 and carriers 20 and 22 are arranged on the inner peripheral side of the output member 24. The rotation decelerated by the deceleration mechanism 18 is transmitted to the output member 24. The output member 24 of the present embodiment also serves as a casing of the deceleration mechanism 18, and an internal gear 38 of the deceleration mechanism 18 is provided on the inner peripheral portion thereof.

A main bearing 46 is arranged between the output member 24 and the carriers 20 and 22. The main bearing 46 of this embodiment is a rolling bearing such as a roller bearing. The carriers 20 and 22 are connected to the vehicle body 12 via a wheel cover 56 described later, and function as a support member that rotatably supports the output member 24 via the main bearing 46.

FIG. 2 is an enlarged view of a part of FIG. The baseband 26 is arranged on the outer peripheral side of the output member 24 and is externally fitted to the output member 24. The baseband 26 has a cylindrical shape as a whole and is made of a metal such as a steel material. Open ends 48 are formed on both sides of the axial direction X on the inner peripheral portion of the baseband 26. The output member 24 is provided so as to be accommodated inside the axial direction X from the opening end 48 of the baseband 26. As will be described later, the baseband 26 is integrated with the output member 24 by being fitted onto the output member 24 by tightening.

The tire 28 is attached to the outer peripheral portion of the baseband 26 by adhesion or the like. The tire 28 is configured by using a soft material softer than the baseband 26. To give an example of this, the tire 28 is configured by using an elastic body such as urethane rubber.

The operation of the deceleration mechanism 18 described above will be described.
When the rotation of the drive source is transmitted from the output shaft 40 to the input shaft 30, the input shaft 30 rotates. When the input shaft 30 rotates, the rotation of the input shaft 30 is decelerated by the deceleration mechanism 18 and transmitted to the output member 24. When the rotation is transmitted from the deceleration mechanism 18 to the output member 24, the tire 28 rotates together with the baseband 26 integrated with the output member 24, so that the tire 28 travels on the traveling surface 16a.

In the deceleration mechanism 18 of the present embodiment, when the input shaft 30 rotates, the eccentric body 32 rotates around the rotation center line La together with the input shaft 30. When the eccentric body 32 rotates around its rotation center line La, the external gear 34 swings so that the axis of the external gear 34 rotates around its rotation center line La. When the external gear 34 swings, the meshing positions of the external gear 34 and the internal gear 38 are sequentially displaced. As a result, each time the input shaft 30 makes one rotation, the internal gear 38 rotates relative to the external gear 34 by the amount corresponding to the difference in the number of teeth from the external gear 34, and the rotation component thereof. Is transmitted to the output member 24. At this time, the rotation of the input shaft 30 is decelerated at a reduction ratio corresponding to the difference in the number of teeth between the external gear 34 and the internal gear 38, and is transmitted from the internal gear 38 to the output member 24.

Here, an outer peripheral tapered surface 50 is provided on the outer peripheral surface of the output member 24 of the present embodiment. The inner peripheral surface of the baseband 26 is provided with an inner peripheral tapered surface 52 that faces the outer peripheral tapered surface 50 of the output member 24 in the radial direction. The outer peripheral tapered surface 50 and the inner peripheral tapered surface 52 are formed so that the outer diameter or the inner diameter is reduced from one side of the axial direction X toward the other side. The outer peripheral tapered surface 50 and the inner peripheral tapered surface 52 of the present embodiment are formed so as to reduce in diameter from the vehicle body side (right side in FIG. 2) in the axial direction X toward the anti-vehicle body side (left side in FIG. 2). To. Hereinafter, of the axial directions X, the direction in which the tapered surfaces 50 and 52 are reduced in diameter is referred to as the diameter reducing direction Pa, and the direction in which the tapered surfaces 50 and 52 are expanded is referred to as the diameter expansion direction Pb.

The outer peripheral tapered surface 50 and the inner peripheral tapered surface 52 are linear tapers whose diameters change linearly (linearly) with respect to a change in distance in the axial direction X. The taper ratios of the outer peripheral tapered surface 50 and the inner peripheral tapered surface 52 are set to the same magnitude. The taper rate here means the rate of change in diameter with respect to the change in distance in the axial direction X. Further, the inner peripheral tapered surface 52 is set so that the axial dimension is larger than that of the outer peripheral tapered surface 50. The axial dimension here means a dimension along the axial direction X. It should be noted that the term "same" in the present specification includes not only the case of being completely the same but also the case of being substantially the same.

The baseband 26 is fitted to the output member 24 by tightening in a state where the tapered surfaces 50 and 52 are in contact with the output member 24. This means that the output member 24 and the baseband 26 have a tightening allowance in the radial direction, and the baseband 26 is externally fitted to the output member 24. It can also be considered that the baseband 26 is externally fitted to the output member 24 in a state where the output member 24 and the baseband 26 are elastically deformed in the radial direction. By fitting using this tight fitting, the baseband 26 is integrated with the output member 24 in a state where the tapered surfaces 50 and 52 are in close contact with the output member 24.

The baseband 26 is provided so as to be located outside the axial direction X from the end face portions 24a on both sides in the axial direction of the output member 24. That is, the output member 24 is covered from the outside in the radial direction by the baseband 26 over the entire length in the axial direction X. The baseband 26 has a flange portion 26a extending from one end on the Pa side in the radial direction (the end having the smaller inner diameter) to the inner peripheral side in the radial direction. The flange portion 26a of the baseband 26 is arranged at a position where it overlaps with the end face portion 24a on the radial direction Pa side of the output member 24 when viewed from the axial direction X.

The flange portion 26a of the baseband 26 and the end face portion 24a on the Pa side in the radial direction of the output member 24 are fastened by bolts B1. The shaft portion of the bolt B1 is inserted into the insertion hole 26b formed in the flange portion 26a and screwed into the female screw hole 24b formed in the end face portion 24a of the output member 24. A gap 54 is formed between the flange portion 26a of the baseband 26 and the end face portion 24a of the output member 24.

In the above wheel drive device 10, as described above, the baseband 26 is externally fitted to the output member 24 by tightening and fitting. Therefore, the relative displacement between the inner peripheral tapered surface 52 and the outer peripheral tapered surface 50 due to the slight vibration can be suppressed, and the occurrence of fretting wear due to the relative displacement can be prevented.

In the structure of Patent Document 1, the contact surface between the rotating body and the wheel is parallel in the axial direction. Therefore, when the wheel is fitted to the rotating body by tightening, the wheel is assembled to the rotating body under the condition that the inner diameter of the wheel is smaller than the outer diameter of the rotating body, and there is a problem in the assembling property of the wheel. .. Further, under the structure of Patent Document 1, the tightening allowance of the rotating body and the wheel cannot be adjusted after the fact. Combined with these, it is difficult to secure the required tightening allowance for preventing fretting wear while obtaining good assembling property.

On the other hand, the baseband 26 of the present embodiment is externally fitted to the output member 24 in a state where the tapered surfaces 50 and 52 are in contact with the output member 24. Therefore, by applying a tightening force in the axial direction X to the baseband 26 and the output member 24 in a state where the outer peripheral tapered surface 50 of the output member 24 is arranged on the inner peripheral side of the inner peripheral tapered surface 52 of the baseband 26. , The state in which the baseband 26 and the output member 24 are tightly fitted can be easily realized. Therefore, the baseband can be easily assembled to the output member 24. The tightening force in the axial direction X here means a force applied in the direction in which the output member 24 and the baseband 26 are brought closer to each other in the axial direction X.

Further, by adjusting the magnitude of the tightening force applied to the baseband 26 and the output member 24 in the axial direction X, the tightening allowance in the radial direction of the baseband 26 and the output member 24 can be adjusted. Therefore, by adjusting the tightening force applied to the baseband 26 and the output member 24, the required tightening allowance required for preventing fretting wear can be easily secured. Combined with these, according to the wheel drive device 10 of the present embodiment, it is possible to effectively take measures against fretting wear.

Further, the flange portion 26a of the baseband 26 and the end face portion 24a of the output member 24 are fastened by bolts B1. Therefore, the tightening force in the axial direction X between the baseband 26 and the output member 24 can be managed through a simple method such as managing the tightening torque of the bolt B1, and the required tightening allowance required to prevent fretting wear can be easily obtained. Can be secured. The tightening torque of the bolt B1 can be managed by using a torque wrench or the like.

Further, a gap 54 is formed between the flange portion 26a of the baseband 26 and the end face portion 24a of the output member 24. The axial dimension of the gap 54 decreases as the tightening allowance between the baseband 26 and the output member 24 increases. Therefore, the tightening allowance between the baseband 26 and the output member 24 can be easily grasped through the visual control of the axial dimension of the gap 54.

Here, the tightening force in the axial direction X (hereinafter, also simply referred to as “tightening force”) applied to the output member 24 and the baseband 26 may be set so as to satisfy the following conditions. It can be said that this is set so as to satisfy the following conditions with respect to the radial tightening allowance of the output member 24 and the baseband 26, or the tightening torque of the bolt B1. The load applied to the baseband 26 and required for the baseband 26 to start rotating is called the starting load [kgf] of the baseband 26.

At this time, the tightening force of the baseband 26 or the like is preferably set so that the starting load of the baseband 26 is 4 kgf or more and 10 kgf or less under the condition that the deceleration mechanism 18 and the power transmission path of the drive source are separated. .. This numerical condition is set based on the experimental study result of the present inventor. The reason for disconnecting the power transmission path between the deceleration mechanism 18 and the drive source is to exclude the rotational resistance of the drive source when considering the starting load of the baseband 26. This disconnection of the power transmission path is realized by removing the input shaft 30 of the deceleration mechanism 18 from the output shaft 40 of the drive source. In the present embodiment, by managing the tightening torque of the bolt B1, the tightening force is set to satisfy the above-mentioned starting load range.

When the starting load of the baseband 26 is less than 4 kgf, the tightening force of the baseband 26 and the like is insufficient, and the tightening allowance of the output member 24 is insufficient. Along with this, sufficient preload is not applied to both of the pair of bearings arranged at intervals in the axial direction X on the inner peripheral side of the output member 24, and there is a concern that the life of these bearings may be shortened. The "pair of bearings" here means, for example, the main bearing 46 on the vehicle body side and the main bearing 46 on the anti-vehicle body side in the present embodiment.

When the starting load of the baseband 26 exceeds 10 kgf, the tightening force of the baseband 26 and the like becomes excessive, and the tightening allowance of the output member 24 becomes excessive. Along with this, the backlash of the reduction mechanism 18 may become excessively small, or the preload of the bearing arranged on the inner peripheral side of the output member 24 may become excessive, and the rotational resistance of the rotating body may become excessively large. The rotating body here is an external gear 34, an internal gear 38, a main bearing 46, and the like. If the rotational resistance of the rotating body becomes excessively large, there is a concern that a large change in the characteristics (hereinafter referred to as no-load characteristics) under the condition that no load is applied to the deceleration mechanism 18 is adversely affected.

When the starting load of the baseband 26 satisfies the above-mentioned conditions, it is possible to realize a tight fitting of the baseband 26 and the output member 24 while preventing the non-load characteristic of the reduction mechanism 18 and the occurrence of adverse effects on the bearing.

A method of measuring the starting load of the baseband 26 will be described. First, the push-pull gauge is attached to the end face portion of the baseband 26 on the side where the flange 48 is located in the axial direction X. Next, the end face portion 24a of the baseband 26 is pulled via the push-pull gauge toward the tangential direction of the circle centered on the rotation axis La of the tire 28. At this time, the tire 28 is kept away from the traveling surface 16a so that no load is applied to the tire 28. When the baseband 26 starts to rotate, the maximum tensile load measured by the push-pull gauge between the start of pulling the push-pull gauge and the start of rotation of the baseband 26 is taken as the starting load of the baseband 26.

The wheel drive device 10 of the present embodiment includes a loosening prevention mechanism 55 for restricting loosening of the bolt B1. The locking mechanism 55 of the present embodiment is a locking washer interposed between the head of the bolt B1 and the flange portion 26a of the baseband 26. As a result, it is possible to prevent the tightening force of the bolt B1 from changing over time, and it is possible to secure the starting load of the baseband 26 for a long period of time. In addition to this, the locking mechanism 55 may be a locking bolt or the like.

Next, other features of the wheel drive device 10 will be described.
See FIG. The wheel drive device 10 includes a wheel cover 56 that covers the baseband 26 and the tire 28. The wheel cover 56 is formed with an opening 56a through which the baseband 26 and the tire 28 project downward. The wheel cover 56 has an inner cover member 58 that is attached to the vehicle body 12 by bolts (not shown) and an outer cover member 60 that is detachably attached to the inner cover member 58 by bolts (not shown).

The inner cover member 58 has an inner side cover portion 58a that covers the baseband 26 and the tire 28 from the diameter-expanding direction Pb in the axial direction X. The inner carrier 20 is fixed to the inner side cover portion 58a by the carrier bolt B3. The inner cover member 58 of the present embodiment also has an outer peripheral cover portion 58b that covers the tire 28 and the baseband 26 from the outer peripheral side.

The outer cover member 60 has an outer side cover portion 60a that covers the tire 28 and the baseband 26 from the radial direction Pa in the axial direction X. The outer carrier 22 is fixed to the outer side cover portion 60a by fitting.

When the outer cover member 60 is removed from the inner cover member 58, a part of the wheel cover 56 does not exist in the radial direction Pa in the axial direction X with respect to the tire 28 and the baseband 26. Therefore, in this state, the tire 28 and the baseband 26 can be replaced by using the space in the radial direction Pa with respect to the tire 28 and the baseband 26 as the working space.

The outer cover member 60 can be removed from the inner cover member 58 while the wheel drive device 10 is attached to the vehicle body 12. Further, when the outer cover member 60 is removed from the inner cover member 58, the bolt B1 can be attached to and detached from the output member 24 and the baseband 26 while the wheel drive device 10 is attached to the vehicle body 12. Further, when the bolt B1 is removed from the output member 24 or the baseband 26, the baseband 26 can be attached to and detached from the output member 24 while the wheel drive device 10 is attached to the vehicle body 12.

A storage space 62 for accommodating the deceleration mechanism 18 is formed on the inner peripheral side of the output member 24. The storage space 62 is sealed by using a plurality of sealing members 64a to 64d. A lubricant (not shown) is sealed in the storage space 62 sealed by the sealing members 64a to 64d.

The sealing members 64a to 64d include an outer peripheral side oil seal 64a interposed between the output member 24 and the carriers 20 and 22, a seal cap 64b that closes the through hole 42 of the outer carrier 22, and a penetration of the inner carrier 20. A shaft cover 64c that closes the hole 42 and an oil seal 64d on the inner peripheral side are included. The outer peripheral side oil seal 64a is arranged between the output member 24 and the carriers 20 and 22 at a position closer to the external space than the main bearing 46. The shaft cover 64c is arranged on the vehicle body side with respect to the input shaft bearing 44, and the input shaft 30 penetrates in the axial direction X. The inner peripheral side oil seal 64d is interposed between the shaft cover 64c and the input shaft 30.

As described above, the sealing members 64a to 64d are arranged between the output member 24 and the carriers 20, 22 and on the inner peripheral side of the through holes 42 of the carriers 20, 22 and between the carriers 20, 22 and the wheel cover 56. Is not placed. Therefore, when the outer cover member 60 of the wheel cover 56 is removed from the inner cover member 58, the storage space 62 on the inner peripheral side of the output member 24 can be maintained in a state of being sealed by the sealing members 64a to 64d. As a result, the tire 28 can be replaced without disassembling the deceleration mechanism 18 or taking in and out the lubricant.

Next, a series of wheel drive devices 10 will be described. The invention of the wheel drive device 10 series (product group) described below is regarded as the invention of the manufacturing method of the wheel drive device 10 series and the invention of the design method (construction method) of the wheel drive device 10 series. You can also do it.

The outer diameter of the tire 28 of the wheel drive device 10 can have various sizes depending on the request from the delivery destination of the wheel drive device 10 and the like. From the viewpoint of reducing management labor, it is desired to standardize the management items as much as possible among the plurality of wheel drive devices 10 having different outer diameters of the tires 28. The series of wheel drive devices 10 of the present embodiment is made under such a background.

The wheel drive series includes a first wheel drive 10-A and a second wheel drive 10-B. The first wheel drive device 10-A is a wheel drive device described with reference to FIGS. 1 and 2. FIG. 3 is a front sectional view of the second wheel drive device 10-B. The second wheel drive 10-B includes components similar to the first wheel drive 10-A in many respects. Hereinafter, similar components in the first wheel drive device 10-A and the second wheel drive device 10-B will be described using the same names. To distinguish similar components between the first wheel drive 10-A and the second wheel drive 10-B, add "first, second" at the beginning of the name and "-A" at the end of the code. , -B "to distinguish.

The second wheel drive device 10-B mainly includes a second deceleration mechanism 18-B, a second carrier 20-B, 22-B, a second output member 24-B, and a second baseband 26-B. And the second tire 28-B. The second deceleration mechanism 18-B and the second carrier 20-B and 22-B are respectively the first deceleration mechanism 18-A and the first carrier 20-A and 22-A of the first wheel drive device 10-A. Common ones are used. The term "common" here refers to the components of the hardware elements (here, deceleration mechanism, carrier) referred to between the first wheel drive 10-A and the second wheel drive 10-B. It means that the shape and dimensions are the same, including the materials of the components.

In the second wheel drive device 10-B, other internal parts arranged on the inner peripheral side of the second output member 24-B are also other internal parts arranged on the inner peripheral side of the first output member 24-A. The one in common with is used. The other internal parts here include an input shaft bearing 44, a main bearing 46, oil seals 64a, 64d, a seal cap 64b, a shaft cover 64c, and the like. As a result, the number of parts to be managed can be reduced between the first wheel drive device 10-A and the second wheel drive device 10-B.

FIG. 4A is an enlarged view of a part of the first wheel drive device 10-A, and FIG. 4B is an enlarged view of a part of the second wheel drive device 10-B. The second output member 24-B is thicker than the first output member 24-A in the entire range of the axial direction X. The thickness here means a dimension along the radial direction. Further, the second output member 24-B has the same shape and axial dimension of the inner peripheral portion and the outer peripheral portion as those of the first output member 24-A. The shape and axial dimension of the inner peripheral portion of the first output member 24-A and the second output member 24-B are the same, that is, the taper ratio and the axial dimension of the outer peripheral tapered surface 50 are the same between them. It also means that. The inner peripheral portion of the second output member 24-B has the same radial dimension as that of the first output member 24-A. Further, the second output member 24-B has the same overall axial dimensions and materials as those of the first output member 24-A. Here, "same shape" means that the contours of the cut surfaces along the axial direction A are the same.

The second baseband 26-B is thicker than the first baseband 26-A in the entire range of the axial direction X. Further, the second baseband 26-B has the same shape and axial dimension of the inner peripheral portion and the outer peripheral portion as those of the first baseband 26-A. The shape and axial dimension of the inner peripheral portion of the first baseband 26-A and the second baseband 26-B are the same, because the taper ratio and the axial dimension of the inner peripheral tapered surface 52 are the same. It also means that they are the same. Further, the second output member 24-B has the same overall axial dimensions and materials as those of the first output member 24-A.

The second tire 28-B has an outer diameter larger than that of the first tire 28-A. Further, the second tire 28-B has the same thickness as the first tire 28 in order to match the running resistance with the first tire 28. Further, the second tire 28-B has the same overall shape, axial dimensions, and material as those of the first tire 28.

Here, as described above, in order to obtain the desired characteristics of the deceleration mechanism 18, it is necessary to manage the tightening force of the baseband 26 and the like so that the required starting load of the baseband 26 can be obtained. In order to standardize the management items among a plurality of wheel drive devices, it is desired to standardize the tightening force.

Against this background, consider the case where the tires 28 having different outer diameters among the plurality of wheel drive devices as described above are used. In this case, the second baseband 26-B so that the outer diameter of the second baseband 26-B increases in accordance with the increase in the outer diameter of the second tire 28-B of the second wheel drive device 10-B. Consider the case of increasing the thickness of the tire. In the present embodiment, the second base has the same thickness as the second tire 28-B and the first tire 28-A, so that the outer diameter of the second baseband 26-B is increased in this way. The thickness of the band 26-B is increased.

In this case, if the output member is also shared among the plurality of wheel drive devices, only the thickness of the second baseband 26-B is increased, and the second output member 24-B becomes the first output member 24-A. It will be the same thickness. At this time, the rigidity of the second baseband 26-B is increased as compared with the first baseband 26-A, while the rigidity of the first output member 24-A and the second output member 24-B are the same.

Here, when a tightening force within a predetermined range in which the required starting load can be obtained by the first wheel drive device 10-A is also applied to the second baseband 26-B or the like of the second wheel drive device 10-B, the following The present inventor has obtained the finding that the above phenomenon occurs. First, in the second baseband 26-B, when a tightening force in the same predetermined range as that of the first wheel drive device 10-A is applied, the first baseband 26-B is increased in rigidity. The amount of deformation toward the outer peripheral side in the radial direction tends to be smaller than that of the baseband 26-A. On the other hand, in the second output member 24-B, as the amount of deformation of the second baseband 26-B from the first baseband 26-A decreases, the radial inner peripheral side of the first output member 24-A The amount of deformation tends to be large. As a result, when the same predetermined range of tightening force as that of the first wheel drive device 10-A is applied to the second baseband 26-B and the second output member 24-B, the first baseband 26-A becomes the first. 2 The starting load of the baseband 26-B may be excessively increased, and the required starting load of the baseband 26 may not be obtained.

(A) Therefore, in the second wheel drive device 10-B of the present embodiment, the thickness of the second baseband 26-B is made larger than that of the first baseband 26-A, so that the first output member 24 The thickness of the second output member 24-B is larger than that of -A. As a result, when the same predetermined range of tightening force is applied to each wheel drive device 10, the second output member has the same thickness as that of the first output member 24-A and the second output member 24-B. It is possible to prevent the amount of deformation of 24-B toward the inner peripheral side in the radial direction from becoming excessively large. As a result, when the same predetermined range of tightening force is applied to each wheel drive device 10, the starting load of the second baseband 26-B is excessively increased from that of the first baseband 26-A, so that the required starting is required. It becomes easier to avoid the situation where the load cannot be obtained.

Here, the present inventor further investigated this problem and found that the balance between the rigidity of the output member 24 and the baseband 26 is important. That is, when the rigidity of the second baseband 26-B is increased more than that of the first baseband 26-A, it is possible to suppress the increase in the amount of deformation of the second output member 24-B from that of the first output member 24-A. Therefore, it is important to increase the rigidity of the second output member 24-B in a well-balanced manner in accordance with the increase in the rigidity of the second baseband 26-B. In other words, if the rigidity of the output member 24 and the baseband 26 is balanced in each wheel drive device 10, it is necessary even when the thickness of the baseband 26 is increased in accordance with the increase in the outer diameter of the tire 28. Each wheel drive device 10 can share a tightening force in a predetermined range required to obtain a starting load. In the series of the present embodiment, in order to balance the rigidity of the output member 24 and the baseband 26 among the plurality of wheel drive devices 10, the following conditions are met with respect to the wall thickness ratio of the output member 24 and the baseband 26. Is stipulated.

First, as a premise, the second output member 24-B has the same shape as the first output member 24-A in the inner peripheral portion and the outer peripheral portion. Further, the second baseband 26-B has the same shape of the inner peripheral portion and the outer peripheral portion as the first baseband 26-A. This is because if the shapes of the first wheel drive device 10-A and the second wheel drive device 10-B are changed, the rigidity of the output member 24 and the baseband 26 cannot be balanced.

Next, the thickness of the minimum outer diameter portion 24c at which the outer peripheral tapered surface 50 of the output member 24 has the minimum diameter is set to tb1 [mm]. The thickness of the maximum outer diameter portion 24d at which the outer peripheral tapered surface 50 of the output member 24 has the maximum diameter is tb2 [mm]. Let ta1 [mm] be the thickness of the small inner diameter portion 26c of the baseband 26 whose position coincides with the minimum outer diameter portion 24c of the output member 24 in the axial direction X. Let ta2 be the thickness of the large inner diameter portion 26d of the baseband 26 whose position coincides with the maximum outer diameter portion 24d of the output member 24 in the axial direction X.

At this time, the thickness tb1 of the minimum outer diameter portion 24c of the output member 24 is set to 1.1 times or more and 1.2 times or less the thickness ta1 of the small inner diameter portion 26c of the baseband 26. Further, the thickness tb2 of the maximum outer diameter portion 24d of the output member 24 is set to be 1.5 times or more and 2.0 times or less the thickness ta2 of the large inner diameter portion 26d of the baseband 26. This numerical condition is set based on the experimental study result of the present inventor. This condition is set to be individually satisfied by both the first wheel drive device 10-A and the second wheel drive device 10-B. That is, when the thickness of the second baseband 26-B is greatly increased from that of the first baseband 26-A, the second baseband 26-B is second than the first output member 24-A within a range corresponding to the thickness of the second baseband 26-B. By making the output member 24-B thicker, the rigidity of the output member 24 and the baseband 26 can be balanced.

When the thickness tb1 of the output member 24 of either the first wheel drive device 10-A or the second wheel drive device 10-B is less than 1.1 times the thickness ta1 of the baseband 26, the output is compared with the baseband 26. The rigidity of the member 24 becomes excessively small. As a result, when the same predetermined range of tightening force is applied to the output member 24 and the baseband 26 in each wheel drive device 10, the output member 24 of the wheel drive device 10 that does not satisfy this condition is directed toward the inner peripheral side in the radial direction. The amount of deformation becomes excessively large, and there is a risk that the required starting load cannot be obtained. The same applies when the thickness tb2 of the output member 24 of any of the first wheel drive device 10-A and the second wheel drive device 10-B is less than 1.5 times the thickness ta2 of the baseband 26.

When the thickness tb1 of the output member 24 of either the first wheel drive device 10-A or the second wheel drive device 10-B is more than 1.2 times the thickness ta1 of the baseband 26, the output is compared with the baseband 26. The rigidity of the member 24 becomes excessively large. As a result, when the same predetermined range of tightening force is applied to the output member 24 and the baseband 26 in each wheel drive device 10, the output member 24 of the wheel drive device 10 that does not satisfy this condition is directed toward the inner peripheral side in the radial direction. The amount of deformation becomes excessively small, and there is a risk that the required starting load cannot be obtained. The same applies when the thickness tb2 of the output member 24 of any of the first wheel drive device 10-A and the second wheel drive device 10-B is more than 2.0 times the thickness ta2 of the baseband 26.

On the other hand, when this condition is satisfied, when the tightening force in the same predetermined range is applied to the baseband 26 and the output member 24 by each wheel drive device 10, the thickness of the baseband 26 and the output member 24 of each wheel drive device 10 is increased. Regardless of the change, it becomes easy to obtain the required starting load of the baseband 26. As a result, the shapes of the inner peripheral portion and the outer peripheral portion of the baseband 26 and the output member 24 are the same, and even if the thickness of the baseband 26 is changed among the plurality of wheel drive devices 10 in which the reduction mechanism 18 is common, it is required. It is possible to standardize the range of tightening force required to obtain the starting load of.

Further, from the viewpoint of the first wheel drive device 10-A that satisfies this condition, the second wheel has the same shape of the inner peripheral portion and the outer peripheral portion of the baseband 26 and the output member 24, and the reduction mechanism 18 is common. Even if the thickness of the baseband 26 is changed between the drive device 10-B and the drive device 10-B, the range of the tightening force required to obtain the required starting load can be standardized.

The examples of the embodiments of the present invention have been described in detail above. All of the above-described embodiments are merely specific examples for carrying out the present invention. The contents of the embodiment do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of components are made within the range not deviating from the idea of the invention defined in the claims. It is possible. In the above-described embodiment, the contents that can be changed in such a design are described with the notations such as "in the embodiment" and "in the embodiment", but the contents are designed without such notations. It's not that changes aren't tolerated. Further, the hatching attached to the cross section of the drawing does not limit the material of the object to which the hatching is attached.

Although the example in which the wheel drive device 10 is incorporated in the transport carriage has been described, the incorporation partner thereof is not particularly limited. Further, although this transport trolley has been described by taking a tracked trolley as an example, a trackless trolley may be used.

The deceleration mechanism 18 has been described by taking an eccentric swing type deceleration mechanism as an example, but the type thereof is not particularly limited. For example, any of a planetary gear mechanism, a parallel shaft gear mechanism, an orthogonal shaft gear deceleration mechanism, a bending mesh deceleration mechanism, and the like may be included. In the case of the eccentric swing type deceleration mechanism, in addition to the center crank type in which the input shaft (eccentric body shaft) is arranged at the axis of the internal gear, there are a plurality of positions offset from the axis of the internal gear. It may be a distribution type in which an input axis (eccentric body axis) is arranged.

Although the example in which the output member 24 also serves as the casing of the speed reduction mechanism 18 has been described, the present invention is not limited thereto. For example, the output member 24 may be arranged on the outer peripheral side of the casing of the deceleration mechanism 18, and may be rotated by the output shaft of the deceleration mechanism 18.

It is not essential that the thickness of the tire 28 is the same as that of the first wheel drive devices 10-A and 10-B. From the viewpoint of obtaining the above-mentioned effect (A), the thickness of the second baseband 26-B is larger than that of the first baseband 26-A, and the second output member 24-B is larger than that of the first output member 24-A. It suffices if the condition that the thickness of is increased is satisfied.

10 ... 1st wheel drive device, 10 ... 2nd wheel drive device, 18 ... deceleration mechanism, 24 ... output member, 24a ... end face portion, 24c ... minimum outer diameter portion, 24d ... maximum outer diameter portion, 26 ... base band, 26a ... Flange portion, 26c ... Small inner diameter portion, 26d ... Large inner diameter portion, 28 ... Tire, 50 ... Tapered surface.

Claims (6)

A deceleration mechanism that slows down the rotation transmitted from the drive source,
A cylindrical output member to which the rotation decelerated by the deceleration mechanism is transmitted, and
A baseband externally fitted to the output member and
A wheel drive device comprising a tire attached to the baseband.
A tapered surface is provided on the outer peripheral surface of the output member and the inner peripheral surface of the baseband.
The baseband is externally fitted to the output member by tightening and fitting in a state where the tapered surfaces are in contact with the output member .
The baseband has a flange portion extending from one end on the radial side to the inner peripheral side in the radial direction.
Have,
A wheel drive device in which the flange portion and the end face portion of the output member are connected with a gap in the axial direction. The wheel drive device according to claim 1, wherein the end face portion of the output member and the flange portion are fastened with bolts in a state where a gap is provided in the axial direction. The thickness of the minimum outer diameter portion where the tapered surface of the output member is the minimum diameter is tb1, the thickness of the maximum outer diameter portion where the tapered surface of the output member is the maximum diameter is tb2, and the minimum outer diameter of the base band. When the thickness of the small inner diameter portion where the position in the axial direction coincides with the portion is ta1, and the thickness of the large inner diameter portion where the position in the axial direction coincides with the maximum outer diameter portion of the base band is ta2.
The thickness tb1 is set to 1.1 times or more and 1.2 times or less the thickness ta1.
Claim 1 in which the thickness tb2 is set to be 1.5 times or more and 2.0 times or less the thickness ta2.
Or the wheel drive device according to 2. The axial tightening force applied to the baseband and the output member is such that the starting load of the baseband is 4 kgf or more and 10 kgf or less under the condition that the power transmission path between the deceleration mechanism and the drive source is separated. The wheel drive device according to any one of claims 1 to 3, which is set to be. A first wheel drive device and a second wheel drive device are provided.
Both the first wheel drive device and the second wheel drive device
A deceleration mechanism that slows down the rotation transmitted from the drive source,
A cylindrical output member to which the rotation decelerated by the deceleration mechanism is transmitted, and
A baseband externally fitted to the output member and
With tires attached to the baseband,
A tapered surface is provided on the outer peripheral surface of the output member and the inner peripheral surface of the baseband.
The baseband is externally fitted to the output member by tightening and fitting in a state where the tapered surfaces are in contact with the output member.
The second wheel drive device includes a tire having an outer diameter larger than that of the first wheel drive device and a tire having an outer diameter.
A series of wheel drive devices having the deceleration mechanism of the first wheel drive device and a common deceleration mechanism.
The output member includes a minimum outer diameter portion having the tapered surface of the output member having the minimum diameter, and a maximum outer diameter portion having the tapered surface of the output member having the maximum diameter.
The baseband includes a small inner diameter portion whose position coincides with the minimum outer diameter portion in the axial direction, and a large inner diameter portion whose position coincides with the maximum outer diameter portion in the axial direction.
The second wheel drive device is
A baseband having a thickness larger than that of the baseband of the first wheel drive device, that is, the small inner diameter portion and the large inner diameter portion.
A series of wheel drive devices having an output member having a thickness of each of the minimum outer diameter portion and the maximum outer diameter portion larger than the output member of the first wheel drive device. A first wheel drive device and a second wheel drive device are provided.
Both the first wheel drive device and the second wheel drive device
A deceleration mechanism that slows down the rotation transmitted from the drive source,
A cylindrical output member to which the rotation decelerated by the deceleration mechanism is transmitted, and
A baseband externally fitted to the output member and
With tires attached to the baseband,
A tapered surface is provided on the outer peripheral surface of the output member and the inner peripheral surface of the baseband.
The baseband is externally fitted to the output member by tightening and fitting in a state where the tapered surfaces are in contact with the output member.
The thickness of the minimum outer diameter portion where the tapered surface of the output member is the minimum diameter is tb1, the thickness of the maximum outer diameter portion where the tapered surface of the output member is the maximum diameter is tb2, and the minimum outer diameter of the base band. When the thickness of the small inner diameter portion where the position in the axial direction coincides with the portion is ta1, and the thickness of the large inner diameter portion where the position in the axial direction coincides with the maximum outer diameter portion of the base band is ta2.
The thickness tb1 is set to 1.1 times or more and 1.2 times or less the thickness ta1.
The thickness tb2 is set to be 1.5 times or more and 2.0 times or less the thickness ta2.
The second wheel drive device includes a tire having an outer diameter larger than that of the first wheel drive device and a tire having an outer diameter.
A series of wheel drive devices having the deceleration mechanism of the first wheel drive device and a common deceleration mechanism.
The output member includes a minimum outer diameter portion having the tapered surface of the output member having the minimum diameter, and a maximum outer diameter portion having the tapered surface of the output member having the maximum diameter.
The baseband includes a small inner diameter portion whose position coincides with the minimum outer diameter portion in the axial direction, and a large inner diameter portion whose position coincides with the maximum outer diameter portion in the axial direction.
The second wheel drive device is
A baseband having a thickness larger than that of the baseband of the first wheel drive device, that is, the small inner diameter portion and the large inner diameter portion.
It has an output member having a thickness of each of the minimum outer diameter portion and the maximum outer diameter portion larger than the output member of the first wheel drive device.
The base band of the second wheel drive device has the same shape as the base band of the first wheel drive device in the inner peripheral portion and the outer peripheral portion.
The output member of the second wheel drive device is a series of wheel drive devices having the same shape as the output member of the first wheel drive device in the inner peripheral portion and the outer peripheral portion.

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