JP2021187338A - Power transmission mechanism - Google Patents

Abstract

To provide a power transmission mechanism that reduces increases in weight, thickness, and length of a propeller shaft.SOLUTION: A power transmission mechanism 10 that includes a propeller shaft 11 extending in an X direction, a pair of drive shafts 12 extending in a Y direction, and a differential device 13 coupling the propeller shaft 11 and the pair of drive shafts 12 so that power can be transmitted and that transmits power between a power source 1 and a pair of drive wheels 2, comprises: a pair of axles 14 affixed to the pair of drive wheels 2 respectively and separate from each other in the Y direction; and a pair of power transmission devices 15 coupling the pair of axles 14 and the pair of drive shafts 12 so that power can be transmitted, in which the pair of drive shafts 12 and the pair of axles 14 are separated from each other in the X direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power transmission mechanism, and more particularly to a power transmission mechanism for transmitting power between a power source and a pair of drive wheels.

In a road-rail vehicle equipped with iron wheels for traveling on railroad rails and tire wheels for traveling on roads, a device in which sprockets are attached to each of the iron wheels and tire wheels and a chain is stretched on the sprockets is proposed. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-193656

By the way, in the power transmission mechanism of a large vehicle such as a truck or a tractor, there is a problem that the propulsion shaft for transmitting power between the power source and the differential device becomes heavy and long. This heavy and long propulsion shaft causes deterioration of fuel efficiency and failure.

The invention described in Patent Document 1 is based on the premise of a road-rail vehicle in which the power source for driving the iron wheels and the power source for driving the tire wheels are different from each other, and is a device as an emergency measure when the power source of the iron wheels fails. Is. Therefore, even if the invention described in Patent Document 1 is simply used, it cannot be an effective means for solving the heavy and long propulsion shaft.

An object of the present disclosure is to provide a power transmission mechanism that suppresses the increase in weight of the propulsion shaft.

The power transmission mechanism of one aspect of the present invention that achieves the above object is a propulsion shaft extending in the front-rear direction of the vehicle, a pair of drive shafts extending in the left-right direction of the vehicle, the propulsion shaft, and the pair. In a power transmission mechanism for transmitting power between a power source and a pair of drive wheels, a differential device for connecting the drive shafts of the above to each of the pair of drive wheels is provided. A pair of axles separated from each other in the left-right direction, a pair of axles thereof, and a pair of power transmission devices for connecting the pair of axles and the pair of drive shafts so as to be able to transmit power are provided, and the pair of drive shafts and the pair of axles are provided. It is characterized in that and are arranged apart from each other in the front-rear direction.

According to one aspect of the present invention, a pair of drive shafts and a pair of axles are configured as separate bodies so that power can be transmitted between the shafts via a power transmission device. The drive wheels can be arranged apart from one end of the propulsion shaft in the front-rear direction of the vehicle. This is advantageous for shortening the length of the propulsion shaft regardless of the arrangement position of the pair of drive wheels, and it is possible to suppress the increase in the weight and length of the propulsion shaft. Along with this, it is possible to improve fuel efficiency and durability.

Further, according to one aspect of the present invention, it is possible to secure a space between a pair of axles separated in the left-right direction by the above configuration. By using this space, it is possible to lower the floor of the vehicle body or provide a storage space under the floor of the vehicle body.

It is a top view which illustrates the power transmission mechanism of 1st Embodiment. It is a side view which illustrates the power transmission mechanism of FIG. It is a top view which illustrates the power transmission mechanism of 2nd Embodiment. It is a side view which illustrates the power transmission mechanism of FIG. It is a top view which illustrates the power transmission mechanism of 3rd Embodiment. It is a side view which illustrates the power transmission mechanism of FIG.

Hereinafter, embodiments of the power transmission mechanism in the present disclosure will be described. In the figure, the X direction is the front-rear direction in the traveling direction of the vehicle, the Y direction is the left-right direction in the vehicle width direction of the vehicle, and the Z direction is the vertical direction. Further, the front side of the vehicle is the left side in the X direction, the rear side is the right side in the X direction, the inside is the center side in the Y direction, and the outside is the upper and lower sides in the Y direction.

As illustrated in FIGS. 1 and 2, the power transmission mechanism 10 of the first embodiment is a mechanism mounted on a vehicle and transmitting power between a power source 1 and a pair of drive wheels 2.

In the present embodiment, the power source 1 is exemplified by an internal combustion engine that outputs power generated by combustion of fuel. The power source 1 of the present disclosure is not limited to the internal combustion engine, and may be composed of an electric motor (including an electric generator having a power generation function) that is driven by the supply of electric power to output power, and is an internal combustion engine and an electric motor. It may be composed of both.

Further, in the present embodiment, the pair of drive wheels 2 are a pair of left and right wheels that are generated by the power source 1 and are rotationally driven by the rotational power output via the power disconnection device (also referred to as a clutch) 3 and the transmission 4. An example is a tire wheel in which a tire is fitted on the outer periphery of the wheel and rolls on a road surface. The drive wheel 2 is not limited to the configuration of a single tire, and may have a configuration of a double tire. The drive wheel 2 of the present disclosure is not limited to the tire wheel, and may be composed of an iron wheel that rolls on the rail as in the embodiment described later.

Each of the power source 1, the power disconnection device 3, the transmission 4, and the power transmission mechanism 10 is supported by a frame (also referred to as a chassis) 5. The frame body 5 is provided with at least two vertical frames extending in the X direction and a plurality of horizontal frames suspended from the vertical frames and extending in the Y direction to form a ladder shape.

The power transmission mechanism 10 is a rear wheel drive mechanism, and is an FR (front engine / rear drive) type mechanism in which the power source 1 is arranged on the front side of the vehicle and the pair of drive wheels 2 are arranged on the rear side of the vehicle. Is. The power transmission mechanism 10 includes a propulsion shaft 11, a pair of drive shafts 12, a differential device 13, a pair of axles 14, a pair of power transmission devices 15, and a pair of suspension devices 16. The power transmission mechanism 10 is a mechanism for a so-called one-def vehicle in which a differential device 13 is one in the power transmission path between the power source 1 and the drive wheel 2. In the power transmission mechanism 10, a pair of drive shafts 12 and a pair of axles 14 are formed separately, and power can be transmitted between the shafts via the power transmission device 15, and the pair of drive wheels 2 Is spaced away from the differential device 13 connected to one end of the propulsion shaft 11 in the X direction.

The propulsion shaft 11 extends in the X direction and the rotation axis direction faces the X direction. The front end in the X direction is connected to the transmission 4, and the rear end in the X direction is the differential device 13. Is linked to. It is desirable that a universal joint be incorporated in the front and rear ends of the propulsion shaft 11 or in the middle position, but this is omitted in the present embodiment.

The drive shaft 12 extends in the Y direction and the rotation axis direction faces the Y direction. The outer end in the Y direction is connected to the power transmission device 15, and the inner end in the Y direction is the differential device 13. Is linked to. The drive shaft 12 in the present embodiment is a separate body from the axle 14 fixed to the drive wheel 2, and is a shaft connected to the differential device 13 to transmit power.

The differential device 13 connects the rear end of the propulsion shaft 11 in the X direction and the inner end of each of the pair of drive shafts 12 in the Y direction to form one propulsion shaft 11 and the pair of drive shafts 12. Makes it possible to transmit the power between them. The differential device 13 is a device capable of causing a difference in the rotation speed of each of the pair of drive shafts 12. The differential device 13 is also referred to as a final deceleration device, but in the present embodiment, the differential device 13 is not the final deceleration device in the power transmission system from the power source 1 to the drive wheels 2.

The axle 14 is an axis that is separate from the drive shaft 12, is an axis that extends in the Y direction and has the rotation axis direction oriented in the Y direction, and the inner end in the Y direction is connected to the power transmission device 15 and Y. The end portion outside the direction is fixed to the drive wheel 2. The axle 14 is parallel to the drive shaft 12 and is spaced away from the drive shaft 12 on the rear side in the X direction. In the present disclosure, the state in which the axes are parallel indicates that the rotation axis of the axle 14 and the rotation axis of the drive shaft 12 are substantially parallel. The separation distance ΔL between the axle 14 and the drive shaft 12 can be freely set by the configuration of the power transmission device 15.

The power transmission device 15 is a device that connects the drive shaft 12 and the axle 14 so as to be able to transmit power. The power transmission device 15 of the present embodiment is composed of a gear transmission device. Specifically, the power transmission device 15 has a first gear 17 fixed to the outer end of the drive shaft 12 in the Y direction and a second gear 18 fixed to the inner end of the axle 14 in the Y direction. The 17 and the second gear 18 are configured to mesh with each other so as to be able to transmit power. The power transmission device 15 may have a configuration having at least three or more gears including the first gear 17 and the second gear 18, and the number of gears is not particularly limited. The power transmission device 15 can freely set the separation distance ΔL between the axle 14 and the drive shaft 12 depending on the diameter of each gear and the number of gears.

Further, the power transmission device 15 of the present embodiment functions as a final deceleration device of the power transmission mechanism 10. It is desirable that the gear ratio of the power transmission device 15 is set so as to be the final reduction ratio by multiplying the gear ratio of the differential device 13. Since the final reduction ratio can be set by both the gear ratio of the differential device 13 and the gear ratio of the power transmission device 15, it is different from the conventional differential device that functions as the final reduction device. It is advantageous to increase the degree of freedom in designing the moving device 13. For example, the differential device 13 can be miniaturized by setting the gear ratio of the differential device 13 to the same magnification. In addition, by increasing the degree of freedom in setting the final reduction ratio, it is possible to set the final reduction ratio according to the application of the vehicle. In the present embodiment, the final reduction ratio is also referred to as the final ratio, which is the reduction ratio when the rotational power output from the transmission 4 is decelerated and transmitted to the drive wheels 2, and is set in advance. Indicates a fixed value. The gear ratio of the power transmission device 15 may be multiplied by the gear ratio of the differential device 13 to obtain the final reduction ratio, and the gear ratio at which the rotation speed of the first gear 17 and the rotation speed of the second gear 18 are equal times. , A gear ratio in which the rotation speed of the first gear 17 is larger than the rotation speed of the second gear 18, or a gear ratio smaller than the rotation speed of the first gear 17 and the rotation speed of the second gear 18 is selected. Gear.

The suspension device (also referred to as suspension) 16 is a device that supports both the drive shaft 12 and the axle 14 together on the frame body 5. The suspension device 16 has a function as a shock absorber that does not transmit vibration due to the unevenness of the road surface transmitted via the drive wheels 2 to the frame body 5, and the drive wheels 2 and the axle 14 are pressed against the road surface to push the drive wheels 2 and the axle 14 to the drive wheel 2 and the axle. It has a function of holding the position of 14 with respect to the road surface. Examples of the suspension device 16 include an axle suspension type (rigid axle suspension), an independent suspension type (independent suspension), and a flexible beam type (torsion beam type suspension).

When the power transmission device 15 is composed of a gear transmission device, it is desirable that the suspension device 16 supports the suspension device 16 while maintaining the relative positions of the drive shaft 12 and the axle 14 to the frame body 5. Specifically, the present invention. The suspension device 16 of the embodiment is an air leaf mixed suspension composed of a laminated leaf spring having both ends in the X direction connected to the frame body 5 via an air spring, and supports both the drive shaft 12 and the axle 14 to the frame body 5. It is configured to do. In this way, even if the suspension device 16 functions as a shock absorber by supporting both the axes of the drive shaft 12 and the axle 14 connected by the power transmission device 15 to the frame body 5, both shafts are used. Since the relative position of the power transmission device 15 does not change, the power transmission device 15 can be configured by the gear transmission device.

Each of the pair of axles 14 is arranged apart from each other in the Y direction. A space 19 is formed between the inner ends of the pair of axles 14 in the Y direction on the rear side in the X direction of the differential device 13. The space 19 of the present embodiment has a length in the X direction from the differential device 13 to the rear end of the vehicle, a width in the Y direction between the inner ends of the pair of axles 14 in the Y direction, and a height in the Z direction. It is a space from the road surface to the lower end of the frame body 5.

The power transmission mechanism 10 transmits the rotational power generated by the power source 1 to the propulsion shaft 11 via the power disconnection device 3 and the transmission 4, and distributes the rotational power to each of the pair of drive shafts 12 by the differential device 13. Next, the power transmission mechanism 10 transmits the rotational power distributed to each of the drive shafts 12 via the power transmission device 15 to the axles 14 to rotationally drive the drive wheels 2. On the other hand, the power transmission mechanism 10 transmits the rotational power transmitted from the pair of drive wheels 2 to the pair of axles 14 via the power transmission device 15 when the rotational power is not output from the power source 1. Communicate to each of. Next, the power transmission mechanism 10 transmits the rotational power transmitted to the drive shaft 12 via the differential device 13 to the propulsion shaft 11.

As described above, according to the power transmission mechanism 10 of the present embodiment, the pair of drive wheels 2 can be arranged apart from the differential device 13 connected to the rear end of the propulsion shaft 11 on the rear side in the X direction. This is advantageous for shortening the length of the propulsion shaft 11 regardless of the arrangement position of the pair of drive wheels 2, and it is possible to suppress the increase in the weight of the propulsion shaft 11. Along with this, it is possible to improve fuel efficiency and durability.

As examples of the arrangement position of the pair of drive wheels 2, a position capable of suppressing the shaking in the X direction and the shaking in the Y direction of the vehicle and a position capable of supporting the load applied to the rear part of the vehicle at the maximum loading of the vehicle in a well-balanced manner are exemplified. Will be done.

Further, according to the power transmission mechanism 10, it is possible to secure a space 19 between the pair of axles 14 separated in the Y direction. For example, the propulsion shaft 11 exists on the front side in the X direction of the differential device 13, and that portion cannot be utilized. On the other hand, this space 19 is a space in which the propulsion shaft 11 and the like do not exist. Therefore, by using this space 19 to lower the floor of the vehicle body (also referred to as the body), it is possible to increase the load capacity of the vehicle body and lower the center of gravity of the vehicle body. Further, by using this space 19 to provide a storage space under the floor of the vehicle body, it is possible to mount a larger battery or a waste heat recovery device for recovering the waste heat of the power source 1. ..

As illustrated in FIGS. 3 and 4, the power transmission mechanism 10 of the second embodiment includes a power transmission device 20 having a different configuration in place of the power transmission device 15 of the first embodiment. Further, the power transmission mechanism 10 of the present embodiment includes suspension devices 24 and 25 having different configurations instead of the suspension devices 16 of the first embodiment.

The power transmission device 20 of the present embodiment is composed of a winding transmission device. Specifically, the power transmission device 20 is wound around a first pulley 21 fixed to the outer end of the drive shaft 12 in the Y direction, a second pulley 22 fixed to the inner end of the axle 14 in the Y direction, and those pulleys. It is configured to have an endless belt 23. The power transmission device 20 may have three or more pulleys including at least the first pulley 21 and the second pulley 22, and the endless belt 23 may be wound around the three or more pulleys. The number of is not particularly limited. The power transmission device 20 can freely set the separation distance ΔL between the axle 14 and the drive shaft 12 by the length of the endless belt 23 in the X direction.

Further, the power transmission device 20 functions as a final deceleration device of the power transmission mechanism 10 like the power transmission device 15 of the first embodiment. It is desirable that the pulley ratio of the power transmission device 20 is set so as to be the final reduction ratio by multiplying the gear ratio of the differential device 13.

The suspension devices 24 and 25 are configured to separately support the drive shaft 12 and the axle 14 on the frame body 5. The suspension device 24 is a device that supports the position of the drive shaft 12 on the frame body 5 at a fixed position. The suspension device 25 is a device that supports the axle 14 on the frame body 5, and has a function as a shock absorber and a function of holding the positions of the drive wheels 2 and the axle 14 like the suspension device 16.

When the drive shaft 12 and the axle 14 are separately supported as in the present embodiment, it is desirable to provide the tension holding device 26 for holding the tension of the belt 23. The tension holding device 26 of the present embodiment has an elongated hole along the circumference of a circle centered on the rotating shaft of the drive shaft 12, and the rotating shaft of the axle 14 inserted through the elongated hole is the drive shaft 12. It is configured to guide the movement of the axle 14 along the circumference of a circle centered on the rotation axis. The tension holding device 26 is not limited to the configuration of the present embodiment, and may be configured by, for example, a plurality of tensioners.

According to the power transmission mechanism 10 of the second embodiment, in addition to the effect of the first embodiment, it is possible to expand the range of vertical movement of the drive wheel 2 as compared with the first embodiment. Therefore, even on a rough road having a large unevenness on the road surface, it is advantageous to move the drive wheel 2 up and down to touch the road surface as much as possible, and it is possible to improve the maneuverability of the vehicle.

The power transmission device 20 of the second embodiment may be composed of a winding transmission device, and includes at least two sprockets, a first sprocket fixed to the drive shaft 12 and a second sprocket fixed to the axle 14. It may be composed of a winding transmission device in which an endless chain is wound around each of a plurality of sprockets.

Further, in the second embodiment, the suspension device 16 that holds the relative positions of the drive shaft 12 and the axle 14 can be applied as in the first embodiment. In this case, the tension holding device 26 can be omitted.

As illustrated in FIGS. 5 and 6, in the power transmission mechanism 10 of the third embodiment, the drive shaft 12 is fixed to the second drive wheel 6 with respect to the second embodiment, and the drive wheel 2 is separated in the X direction. The difference is that the power is transmitted to a plurality of drive wheels of the second drive wheel 6. Further, the power transmission mechanism 10 of the third embodiment includes a power transmission device 20 in which the pulley ratio is set to the same magnification.

The second drive wheel 6 is a pair of left and right wheels configured separately from the drive wheel 2, and a tire wheel in which a tire is fitted on the outer periphery of the wheel and rolls on a road surface is exemplified. Like the drive wheel 2, the second drive wheel 6 is not limited to a single tire and may be a double tire.

The drive shaft 12 of the present embodiment is an axis extending in the Y direction and the rotation axis direction is oriented in the Y direction, the end portion outside the Y direction is fixed to the second drive wheel 6, and the position in the middle in the Y direction is set. It is connected to the power transmission device 20, and the end portion inside in the Y direction is connected to the differential device 13.

The suspension device 24 of the present embodiment is a device that supports the drive shaft 12 on the frame body 5, and like the suspension device 16, functions as a shock absorber and holds the positions of the second drive wheel 6 and the drive shaft 12 with respect to the road surface. Has a function to do.

The tension holding device 26 is arranged for each of the suspension devices 24 and 25. The tension holding device 26 arranged in the suspension device 24 has an elongated hole along the circumference of a circle centered on the rotating shaft of the axle 14, and the rotating shaft of the drive shaft 12 inserted through the elongated hole is the axle 14. It is configured to guide the movement of the drive shaft 12 along the circumference of a circle centered on the rotation axis of. The tension holding device 26 arranged in the suspension device 25 has the same configuration as that of the second embodiment.

According to the power transmission mechanism 10 of the third embodiment, in addition to the effects of the first embodiment and the second embodiment, one differential device 13 drives the drive wheels 2 and the second drive wheels 6. It becomes possible to obtain a larger driving force. Further, according to the power transmission mechanism 10, it is possible to increase the degree of freedom in design as compared with a mechanism for a so-called two-def vehicle equipped with two differential devices 13. For example, it is possible to increase the separation distance between the drive wheel 2 and the second drive wheel 6.

The power transmission mechanism 10 of the third embodiment can also be applied to a road-rail vehicle in which either the drive wheel 2 or the second drive wheel 6 is composed of tire wheels and the other is composed of iron wheels rolling on rails. Is. In the road-rail vehicle, both a method of traveling only with iron wheels and a method of traveling with both iron wheels and tire wheels when traveling on rails are exemplified, but the power transmission mechanism 10 is applied to both methods. It is possible. In a road-rail vehicle that travels only on iron wheels when traveling on rails, the tire wheels are in contact with the road surface and the iron wheels are separated from the rails, or the tire wheels are separated from the road surface and the iron wheels are in contact with the rails. It is configured to switch to either state. When the power transmission mechanism 10 is applied to a road-rail vehicle, the device corresponding to the iron wheel among the suspension devices 24 and 25 has a function of raising and lowering the iron wheel and the shaft fixed to the iron wheel up and down in the Z direction. Is desirable. Further, when the power transmission mechanism 10 is applied to a road-rail vehicle, the pulley ratio of the power transmission device 20 is not limited to the same magnification.

The power transmission mechanism 10 of the above-described embodiment exemplifies a rear-wheel drive FR system mechanism, but the power transmission mechanism 10 is an RR (rear engine / rear drive) system mechanism or an MR (midship engine / rear drive) system. It is also applicable to front wheel drive as well as rear wheel drive. Further, the power transmission mechanism 10 can also be applied to a four-wheel drive or all-wheel drive mechanism.

1 Power source 2 Drive wheel 6 Second drive wheel 10 Power transmission mechanism 11 Propulsion shaft 12 Drive shaft 13 Differential device 14 Axle 15, 20 Power transmission device 16, 24, 25 Suspension device

Claims (8)

It is provided with a propulsion shaft extending in the front-rear direction of the vehicle, a pair of drive shafts extending in the left-right direction of the vehicle, and a differential device for connecting the propulsion shaft and the pair of drive shafts so as to be able to transmit power. In the power transmission mechanism that transmits power between the power source and the pair of drive wheels
It is provided with a pair of axles fixed to each of the pair of drive wheels and separated from each other in the left-right direction, and a pair of power transmission devices for connecting the pair of axles and the pair of drive shafts so as to be able to transmit power. , A power transmission mechanism characterized in that the pair of drive shafts and the pair of axles are spaced apart from each other in the front-rear direction. The power transmission mechanism according to claim 1, wherein the pair of drive wheels are composed of tire wheels in which tires are fitted on the outer periphery of the wheels and roll on the road surface. Each of the pair of drive shafts is fixed to each of the pair of second drive wheels.
The power transmission mechanism according to claim 1, wherein the pair of drive wheels and the pair of second drive wheels are composed of tire wheels in which tires are fitted on the outer periphery of the wheels and roll on the road surface. Each of the pair of drive shafts is fixed to each of the pair of second drive wheels.
One of the pair of drive wheels and the pair of second drive wheels is composed of tire wheels in which tires are fitted on the outer circumference of the wheels and rolls on the road surface, and the other is an iron wheel that rolls on rails. Configured,
The first aspect of the present invention is configured to switch to either a state in which the tire wheel is in contact with the road surface and the iron wheel is separated from the rail, or a state in which the tire wheel is separated from the road surface and the iron wheel is in contact with the rail. The power transmission mechanism described. The power transmission device is composed of a gear transmission device in which a plurality of gears including at least two gears of a first gear fixed to the drive shaft and a second gear fixed to the axle are meshed with each other. The power transmission mechanism according to any one of 4. The power transmission mechanism according to claim 5, further comprising a suspension device that supports both the drive shaft and the axle connected by the power transmission device together while maintaining their relative positions. The power transmission device is a winding in which an endless belt is wound around each of a plurality of pulleys including at least two pulleys of a first pulley fixed to the drive shaft and a second pulley fixed to the axle. A power transmission device or a winding in which an endless chain is wound around each of a plurality of sprockets including at least two sprockets of a first sprocket fixed to the drive shaft and a second sprocket fixed to the axle. The power transmission mechanism according to any one of claims 1 to 4, wherein the power transmission mechanism comprises a sprocket transmission device. The power transmission mechanism according to claim 7, further comprising a suspension device that separately supports the drive shaft and the axle connected by the power transmission device, and a tension holding device that holds the tension of the belt or the chain. ..

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