JPH09280323A - Wheel motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel motor in which a reduction ratio of a two-stage planetary gear speed reduction mechanism can be increased by devising its structure. SOLUTION: A first planetary speed reduction gear mechanism 9 comprises a drive gear 14 formed on a motor shaft 13, a first ring gear 15 formed in an inner circumference of a rotary case 8, and a free self-rotating and revolving first planetary gear 16 engaged with these both gears 14, 15. A second planetary speed reduction gear mechanism 10 is comprised of a sun gear 18 fitted through a bearing outside the motor shaft 13, engaged with a transmission gear 19 integral with a planetary gear shaft 17 rotatably supporting the first planetary gear 16 so as to transmit a driving power, a second ring gear 23 formed at an inner circumference of the rotary case 8, and a second planetary gear 24 engaged with these both gears 18, 23 which is rotatable only in its self-rotation, wherein the first ring gear 15 is made to have a larger diameter than that of the second ring gear 23.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of a hydraulic wheel motor with a planetary speed reduction mechanism. It is suitable for a crawler traveling device such as a backhoe and a combine.

[0002]

2. Description of the Related Art The above wheel motor is disclosed in JP-A-7-30.
As disclosed in Japanese Patent No. 1205, a two-stage planetary speed reduction mechanism is provided between a rotating case to which a crawler sprocket is attached and a motor shaft, and a required torque is obtained by integrating the motor and the speed reduction mechanism. It is a compact product.

[0003]

The reduction ratio of the structure of the two-stage planetary reduction mechanism will be described with reference to FIG. 2. The number of teeth of the drive gear 14 formed on the motor shaft 13 is Z1, and the first ring gear 15 is used. Is Z3, the number of teeth of the sun gear 18 externally fitted on the motor shaft 13 is Z4, and the number of teeth of the second ring gear 23 is Z6. The reduction ratios i1 and i2 and the total reduction ratio i are i = − (i1 × i2-1) = − ([(Z1 + Z3) ÷ Z1] × [(Z4 +
Z6) ÷ Z4] −1), and the minus sign means that the motor shaft and the rotating case rotate in reverse. In other words, to increase the reduction ratio,
The number of teeth of the drive gear 14 and the sun gear 18 is reduced, and the number of teeth of the first and second ring gears 15 and 23 is increased. The opposite is true to reduce the reduction ratio.

Therefore, in order to increase the versatility of the wheel motor, it is desired to expand and set the range of the reduction ratio, but it is difficult to expand the diameter of the rotating case due to the structure in which the sprocket is externally fitted and mounted, and the drive gear is also used. Also, it is difficult to reduce the diameter of the sun gear because of its strength. Therefore, it is difficult to set the reduction ratio to a larger side than the current one, and there is room for improvement in that respect. An object of the present invention is to provide a wheel motor capable of increasing the reduction ratio of the two-stage planetary reduction mechanism by devising the structure.

[0005]

[Means for Solving the Problems]

[Configuration] To achieve the above object, the present invention provides a motor shaft,
In a wheel motor in which the first and second planetary speed reduction mechanisms are provided in a state of surrounding the motor shaft and between the motor shaft and a rotating case having a coaxial center, the first planetary speed reduction mechanism is A drive gear attached to the motor shaft, a first ring gear formed on the inner circumference of the rotating case, and a first planetary gear that is rotatable and revolvable and meshes with the drive gear and the first ring gear. The second planetary speed reduction mechanism is formed on the inner circumference of the rotating case, and a sun gear that is rotatably supported by the motor shaft and that is rotatably supported by the first ring gear and is meshed with the planetary shaft to transmit power. A second ring gear and a second planetary gear that is free to rotate and meshes with the sun gear and the second ring gear, and the first ring gear has a larger diameter than the second ring gear. The It is an characteristic configuration.

Then, it is convenient to construct the first ring gear and the second ring gear as parts independent of each other.

Further, it is more convenient if the second ring gear is mounted on the rotary case by interlocking the outer circumference of the second ring gear with the first ring gear.

[Operation] The structure of claim 1 is a means for increasing the reduction ratio by making the diameter of the first ring gear, which is the lower transmission torque side, larger than that of the second ring gear, which is the higher transmission torque side. That is, in the past, the first and second ring gears were formed as the same gear on the inner circumference of the rotating case in order to obtain an advantage in gear processing, but the torque acting on the first ring gear is lower than the torque acting on the second ring gear. Because it is small, it is possible to reduce the thickness of the rotating case in that portion.

That is, as shown in FIG. 2, the rotating case 8
It has become possible to increase the diameter of the first ring gear 15 formed at the outer end portion of the case, while allowing the sprocket 5 to be mounted from the outside while keeping the outer diameter of the case almost unchanged from the conventional one. Therefore, the reduction ratio i1 of the first planetary reduction mechanism can be increased to increase the total reduction ratio i, and even if the reduction ratio i2 of the second planetary reduction mechanism is slightly reduced due to the increased torque (i.e. Even if the diameter of the 2 ring gear is slightly smaller), the total reduction ratio i can be made larger than before.

According to the second aspect of the present invention, the second ring gear, which has a severe torque condition, can be made of a material having higher strength than the first ring gear, and the tooth strengths of the first and second ring gears are suitable for the torque condition. It can be set to. For example, the first ring gear is made of a cast material forming the rotating case, and the second ring gear is made of carbon steel.

In order to integrally attach the second ring gear, which is a separate body, to the rotating case, it is usual to form spline fitting means and serration fitting means on both of them. On the other hand, in the structure according to claim 3, since the outer circumference of the second ring gear is integrated with the rotating case by utilizing the outer circumference of the second ring gear, the spline fitting means and the like are provided separately. The processing man-hour can be reduced.

[Effect] With the wheel motor according to any one of claims 1 to 3, the reduction ratio of the two-step planetary gear mechanism can be increased without increasing the size of the rotating case.
It was possible to improve the versatility by expanding the setting range of the reduction ratio without causing the inconvenience of mounting on the actual machine such as the conventional crawler sprocket cannot be used.

In the wheel motor according to the second or third aspect of the invention, the tooth strength of the first and second ring gears can be matched to the torque, and the durability and reliability can be improved.

The wheel motor according to claim 3 has an advantage that the effect due to the configuration of claim 2 can be obtained in an economical state with little cost increase.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The backhoe is shown in FIG.
Is an excavation work device, 2 is a swivel base, 3 is a traveling platform, and 4 is a crawler for traveling. The crawler 4 is driven by a drive sprocket 5 on the rear side, and the drive sprocket 5 is driven by a hydraulic wheel motor M configured around its axis Q. The structure of the wheel motor M will be described below.

A wheel motor M is shown in FIG. 2, 6 is a variable displacement hydraulic motor capable of shifting between high and low stages, 7 is a motor housing fixed to the traveling machine base 3, 8 is a rotating case, and 9 is a first. The first planetary speed reduction mechanism 10 is a second planetary speed reduction mechanism. The rotating case 8 is externally fitted to the motor housing 7 so as to be rotatable relative to the motor housing 7, and has a flange 11 for bolting the drive sprocket 5 to the inner end of the outer periphery thereof, and an inlay fitted to the inner periphery of the drive sprocket 5. The part 12 is formed.

The first planetary reduction mechanism 9 includes a drive gear 14 formed on the motor shaft 13, a first ring gear 15 integrally formed on the inner circumference of the rotating case 8, and the drive gear 14 and the first ring gear 15. It is composed of a plurality of first planetary gears 16 which are rotatable and revolvable so as to engage with each other. A planet shaft 17 on which the first planet gear 16 is rotatably fitted.
A transmission gear 19 that meshes with a sun gear 18, which will be described later, is attached by means of a pin 20 in an integrally rotating state, and a connecting plate 22 arranged between the motor shaft 13 and the wheel cover 21 is fitted therein. That is, the plurality of planetary shafts 17, the transmission gear 19, and the connecting plate 22 constitute a carrier that supports the first planetary gear 16.

The second planetary reduction mechanism 10 is rotatably supported by the motor shaft 13 and is meshed with a transmission gear 19 (corresponding to the planetary shaft 17 rotatably supporting the first planetary gear 16). The sun gear 18 to which power is transmitted, the second ring gear 23 formed on the inner circumference of the rotating case 8, and a plurality of second planetary gears 24 that are meshed with the sun gear 18 and the second ring gear 23 and are rotatable only. It consists of and. The second planetary gear 24 is externally fitted to the bearing on a support block 25 bolted to the side wall of the motor housing 7. The second ring gear 23 is integrally mounted on the rotating case 8 by engaging with the inward extension of the first ring gear 15, and the first ring gear 15 is made of cast iron, while the second ring gear 23 is made of carbon steel. So-called "gear material" such as
It is composed of a strong material called.

That is, the effective diameter of the first ring gear 15 is
The reduction ratio of the first planetary reduction mechanism 9 is increased by making it larger than that of the second ring gear 23, and as a result, the total reduction ratio is set to a value larger than that of the conventional one. Although the outer diameter of the first ring gear 15 portion of the rotating case 8 is slightly larger than that of the second ring gear 23 mounting portion, since it is smaller than the diameter of the spigot portion 12, there is no problem in mounting the sprocket 5. .

As shown in FIGS. 2 and 3, the connecting plate 2
Reference numeral 2 is formed in a bent shape in which a contact portion with the inner protrusion 21a of the wheel cover 21 and a portion externally fitted to the protrusion 13a at the end of the motor shaft 13 are formed. In addition, the inner protrusions 21a are circumferentially formed at four places at equal intervals, and the inner protrusions 21a adjacent to each other are
A passage 30 for the lubricating oil is formed between the portions a by the inner protrusions 21a, 21a and the connecting plate 22.
A magnet 27 is attached to an oil test plug 26 provided at the center of the wheel cover 22. That is, the space S surrounded by the connecting plate 22 and the wheel cover 21 becomes an oil sump having the passage 30, and the oil sump attracts fine iron powder such as cutting chips at the time of machining to the magnet. By sucking with 27, the filter function can be exerted.

As shown in FIGS. 2 and 4, the motor housing 7 is bolted to the track frame 28, which is a member on the side of the traveling machine base 3, via a knock pin 29. That is, not only the bolts but also the knock pins 29 are made to share the shearing force due to the torque reaction force of the wheel motor M, so that the bolts are prevented from loosening while the number of bolts is reduced.

[Other Embodiments] Not only the first ring gear 15 but also the second ring gear 23 may be formed integrally with the rotating case 8. In addition, the hydraulic motor 6 is provided rather than the first ring gear 15.
A structure in which a spline portion is formed on the side and a separate second ring gear 23 is spline-fitted and attached thereto may be used.

[Brief description of drawings]

1] Side view of backhoe

FIG. 2 is a sectional side view of the wheel motor.

FIG. 3 is a side view showing the structure of an oil sump portion.

FIG. 4 is a rear view showing a mounting state of the wheel motor.

[Explanation of symbols]

 8 Rotation Case 9 First Planetary Reduction Mechanism 10 Second Planetary Reduction Mechanism 13 Motor Shaft 14 Drive Gear 15 First Ring Gear 16 First Planetary Gear 17 Planetary Shaft 18 Sun Gear 23 Second Ring Gear 24 Second Planetary Gear

Claims (3)

[Claims] 1. A wheel motor in which first and second planetary reduction gear mechanisms are provided between a motor shaft and a rotating case surrounding the motor shaft and having a coaxial center with the motor shaft. The first planetary reduction mechanism includes a drive gear attached to the motor shaft and a first gear formed on the inner circumference of the rotating case.
A ring gear, and a first planetary gear that is rotatable and revolvable and meshes with the drive gear and the first ring gear. The second planetary reduction mechanism is rotatably supported by the motor shaft, and A sun gear for transmitting power by engaging a planetary shaft that rotatably supports the first planetary gear, a second ring gear formed on the inner circumference of the rotating case, and the sun gear and the second ring gear. A wheel motor configured by a second planetary gear that freely rotates and that meshes with each other, wherein the first ring gear has a larger diameter than the second ring gear. 2. The wheel motor according to claim 1, wherein the first ring gear and the second ring gear are configured as parts independent of each other. 3. The wheel motor according to claim 2, wherein the second ring gear is mounted on the rotating case by fitting the outer circumference of the second ring gear into the first ring gear.