JP2004051045A - Caster wheel and carriage provided with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a caster wheel capable of preventing swing in right and left directions when reversing a traveling direction and preventing it from becoming a reverse caster condition even on a steep slope. <P>SOLUTION: This caster wheel is provided with a wheel 12 supported rotatably by a boss 11 which is an inner ring, a wheel shaft 13 attached to a position eccentric from the center of the boss 11, a guide member 14 supporting the wheel shaft 13 rotatably, and a fixing member 16 supporting the guide member 14 turnably. Since the wheel is offset for the guide member by rotating the wheel shaft 13, the caster wheel does not swing in the right and left directions when reversing a traveling direction and does not become the reverse caster condition even on the slope having the steep grade to allow stable traveling. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a caster wheel, and more particularly to a caster wheel for a traveling trolley in which the wheel does not turn around a caster axis offset from a wheel axis when the wheel reverses the traveling direction, and a trolley provided with the caster wheel. Things.
[0002]
[Prior art]
In a conventional caster wheel (free wheel), the rotating shaft 2 of the wheel 1 is oriented parallel to the road surface, and the rotating shaft 2 is displaced (offset) by H with respect to the turning shaft 3 as shown in FIGS. It is arranged. Further, the turning shaft 3 is fixed to a bogie, furniture, a chair, or the like by a fixing portion 4 with a bolt 5 or the like. In this caster wheel, due to the presence of the offset, when a force in a predetermined direction is applied to a bogie or the like to which the caster wheel is attached, the wheel 1 easily turns around the turning shaft 3 and follows the direction. And can change direction.
[0003]
[Problems to be solved by the invention]
However, in the above-described caster wheels for bogies, when a certain amount of weight is applied to the wheels 1 when reversing the running direction, the wheels 1 turn around the grounding point A between the wheels 1 and the road surface. The trolley or the like that has been swung will be swung right and left by the offset amount. Therefore, for example, in a system in which the caster wheels are provided on a rail traveling type bogie, and the rack pin provided on the rail side engages with the bogie side pin pinion gear, the caster turns to drive the bogie with the pin pinion gear. There is a possibility that the transmission of the driving force becomes impossible due to a change in the distance in the tooth height direction from the vertically arranged rack pin.
[0004]
In addition, since the direction of swinging the bogie to the left and right differs depending on the running direction (the direction of the caster wheels) immediately before reversing, it is difficult to balance the loaded load, causing load collapse, and in some cases, The bogie was swung in the opposite direction, resulting in poor running stability and poor riding comfort.
Further, as shown in FIG. 10, in order for the wheel 1 to turn 360 degrees around the turning axis (caster axis) 3, it is necessary to provide a margin (dead space) corresponding to the turning radius around the caster wheels in the bogie itself. did.
[0005]
Further, as another conventional example, the wheel is rotated around the caster axis when the running direction is reversed when the rotation axis of the wheel is loosely fitted in a long groove formed parallel to the road surface and formed in a direction parallel to the road surface. There is proposed a structure that prevents the above.
However, in caster wheels with such a structure, the rotating shaft of the wheel can move freely in the long hole, so when descending a steep slope, the rotating shaft of the wheel moves forward in the traveling direction due to the load condition. As a result, there is a possibility that the vehicle may be in a reverse caster state and stable running cannot be ensured.
[0006]
In order to solve the above problems, the present invention enables the wheels to be offset by eccentrically supporting the boss which is the inner ring of the wheels, does not swing left and right when reversing the running direction, and even on steep slopes It is an object of the present invention to provide a caster wheel having a caster wheel that does not enter a reverse caster state and a cart having the caster wheel.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a wheel rotatably supported by a boss serving as an inner ring, a wheel shaft mounted at a position eccentric from the center of the boss, and a guide member rotatably supporting the wheel shaft. A fixing member for rotatably supporting the guide member, wherein the wheel shaft is rotated to offset the wheel with respect to the guide member. The eccentricity of the wheel shaft with respect to the boss due to the rotation of the wheel can offset the wheel shaft with respect to the guide member.
[0008]
The invention according to claim 2 is the caster wheel according to claim 1, wherein a rotation resistance between the boss and the wheel is different from a rotation resistance between the wheel shaft and the guide member. . Due to the difference in rotation resistance, eccentricity due to rotation of the wheel can be generated.
[0009]
The invention according to claim 3 is characterized in that a portion between the boss and the wheel is supported by a sliding bearing, and a portion between the wheel shaft and the guide member is supported by a rolling bearing. Due to the difference in operation principle between the plain bearing and the rolling bearing, the rotation resistance can be made different.
[0010]
The invention according to claim 4 is characterized in that a diameter of a bearing rotatably supporting between the boss and the wheel is larger than a diameter of a bearing rotatably supporting between the wheel axle and the guide member. I do. Generally, the rolling resistance of a rolling bearing increases as the bearing diameter increases, so that the rolling resistance can be made different.
[0011]
The invention according to claim 5 is characterized in that it has a stopper that regulates a turning range of the guide member with respect to the fixing member. The turning range can be set to a predetermined range by the stopper.
[0012]
The invention according to claim 6 is characterized in that the wheel has a groove on the outer periphery. When the groove engages with the rail, the wheel can be prevented from coming off.
[0013]
The invention according to claim 7, wherein a wheel rotatably supported by a boss that is an inner ring, a wheel shaft mounted at a position eccentric from the center of the boss, and a guide member rotatably supporting the wheel shaft, A fixing member for rotatably supporting the guide member; and a caster wheel for offsetting the wheel with respect to the guide member by rotation of the wheel shaft.
[0014]
The invention according to claim 8 is characterized in that the caster wheel includes a drive pinion gear that runs on a rail and meshes with a pin rack rail arranged along the rail. The vehicle body can be moved by driving the drive pinion gear.
[0015]
The invention of claim 9 is characterized in that the caster wheel has a groove on the outer periphery and travels while engaging with a projection formed on the rail tread surface. The engagement between the groove and the projection can prevent the wheel from coming off.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway side view showing an embodiment of a caster wheel according to the present invention, and FIG. 2 is a longitudinal sectional view of the caster wheel of the present invention. Here, the caster wheel 10 has a wheel 12 rotatably supported by a boss 11 serving as an inner ring, a wheel shaft 13 attached to a position G2 eccentric from a center G1 of the boss 11, and a rotatable wheel shaft 13. And a fixing member 16 for rotatably supporting the guide member 14 with a thrust bearing 15 or the like.
[0017]
The wheel 12 is rotatably supported by a disk-shaped boss 11 which is an inner ring, and is supported by sliding engagement or a bearing 17. The boss 11 has a wheel shaft 13 penetrated at a position G2 offset from the center G1 of the disk by, for example, 10 to 20 mm. The boss 11 and the wheel shaft 13 are integrally fixed. Further, both ends of the wheel shaft 13 are rotatably supported by bearings 18 which are rolling bearings. When the wheel 12 and the boss 11 are in sliding engagement and both ends of the wheel axle 13 are supported by bearings 18, the rotational resistance of the wheel axle 13 is smaller than the rotational resistance of the wheel 12. When moving, the wheel shaft 13 first rotates and the wheel 12 is eccentric.
[0018]
As a specific example of providing a difference between the rotational resistance of the wheel axle 13 and the rotational resistance of the wheel 12, when both are supported by bearings, even if the diameter of the bearing is provided and the diameter of the bearing 17 is larger than the diameter of the bearing 18. Good.
[0019]
The guide member 14 is supported by a fixed portion 16 by a thrust bearing 15 so as to be pivotable about a pivot axis L (usually provided vertically). Further, the guide member 14 has a gate shape and has a concave portion 14a for accommodating the wheel 12 in the center. Further, a through hole 14c is formed horizontally in the left and right leg portions 14b of the guide member 14, and a bearing 18 is provided in the through hole 14c. Further, the rotating shaft 13 is rotatably mounted on the bearing 18, and the boss 11 is integrally mounted on the center of the rotating shaft 13.
[0020]
The guide member 14 has a stopper 19 that regulates a turning range with respect to the fixed member 16 as shown in FIG. The guide member 14 does not need to turn 360 degrees about the turning axis L, but it is sufficient if the guide member 14 can turn within a range corresponding to the curvature of the curve of the traveling rail. The stopper 19 contacts the side surface of the turning guide member 14 to restrict the turning range of the caster wheel 10. The stopper 19 is provided on a part of the turning axis L, and the stopper 19 It may restrict the turning range.
[0021]
The operation of the caster wheel configured as described above will be described with reference to FIGS. First, as shown in FIGS. 1 and 2, when the caster wheel 10 is stopped, the center G1 of the boss 11, which is a disk, and the axis G2 of the wheel shaft 13 are on the same vertical line, and are in a neutral state with no offset amount. . This is because the wheels 12 do not receive the running resistance from the tread rails 20, and the boss 11 does not receive the rotational force.
[0022]
Next, as shown in FIG. 3, when the caster wheel 10 travels in the direction of the arrow X, the wheel 12 is moved from the tread rail 20 by a running resistance Y in the direction opposite to the running direction so that the boss 11 is rotated by θ around the axis G2 of the wheel shaft 13. Rotate. At this time, since the rotational resistance of the plain bearing is generally larger than the rotational resistance of the rolling bearing, the rotational resistance of the wheel shaft 13 is smaller than the rotational resistance of the wheel 12. Therefore, when moving from a stationary state, the wheel shaft 13 rotates first and the wheel 12 is eccentric. The amount of eccentricity is the distance between G1 and G2 × sin θ. This eccentric amount is set to be 10 to 20 mm. Further, the wheel 12 descends by Δh.
[0023]
Even if the wheels 12 travel on the floor or the tread rail 20 in the direction of the arrow X in the offset state, stable traveling is possible. Also, even if the tread rail 20 is steeply inclined forward, the wheels 12 are subjected to running resistance, so that stable running can be performed without maintaining the offset state and being in the reverse caster state.
[0024]
Next, a case where the caster wheels 10 travel in a direction opposite to the direction in which the wheels have traveled so far will be described. When the wheel 12 stops rotating by receiving a force in the opposite direction from the state shown in FIG. 3, the center G1 of the disk and the axis G2 of the wheel shaft 13 are on the same vertical line as shown in FIGS. It becomes a neutral state with no offset amount. When the wheel 12 starts to rotate in the reverse direction by receiving the force in the opposite direction, the boss 11 rotates around the axis G2 of the wheel shaft 13 by θ in the direction opposite to the case shown in FIG. Also at this time, since the rotation resistance of the wheel shaft 13 is smaller than the rotation resistance of the wheel 12, the boss 11 first rotates about the wheel shaft 13 and the wheel 12 is eccentric.
[0025]
Similarly, since the wheel 12 is displaced (offset) with respect to the turning axis L of the guide member 14, even if the floor surface or the tread rail 20 is steeply inclined in the opposite direction, it becomes an inverted caster state and becomes unstable. Nothing. Further, when changing the direction, the boss 11 supporting the wheel 12 only rotates by a predetermined angle around the wheel axis 13 and does not need to rotate around the turning axis L, so that no extra space is required around the turning axis L. . Further, when traveling in a certain direction, the wheels 12 are always offset, so that stable traveling can be ensured even when the road surface changes or the tread rail curves.
[0026]
FIG. 6 is a main part front view showing another embodiment of the caster wheel of the present invention. In the present embodiment, the wheel 21 has a groove 22 for engaging with the rail 23 on the outer periphery. In the case of such a configuration, there is no possibility that the wheels 21 come off from the tread surface of the rail 23, and the bogie or the like can stably travel on the rail.
[0027]
FIG. 7 is a perspective view showing an example of a drive mechanism of a truck having caster wheels of the present invention, and FIG. 8 is a side view of the truck of the present invention. The cart 24 has four caster wheels 10 mounted below a cart frame 25 and rests on rails 26. Further, rack pins 27 are laid at equal intervals between the left and right rails 26, and a pin pinion gear 28 provided on the carriage 24 meshes with the rack pins 27. Therefore, by driving the pin pinion gear 28 to rotate by the drive mechanism 29 provided on the carriage 24, the carriage 24 can be moved forward and backward even on a steeply inclined rail. Further, the guide roller 30 provided on the cart 24 abuts on the reinforcing flange 31 provided on the upper portion of the rack pin 27 to regulate the movement of the cart in the width direction. The caster wheels 10 are attached to four places on the lower surface of the cart 24, and support the weight of the cart and follow it. The caster wheel 10 has the above-described structure.
[0028]
In the truck 24 configured as described above, the wheels 12 are supported by the bosses 11 on which the caster wheels 10 are eccentrically supported, and the displacement is maintained by running resistance. Therefore, it is possible to maintain stable running without moving forward and in the reverse caster state. Also, when the traveling direction is changed, the boss 11 that supports the wheel 12 only rotates about the wheel shaft 13, so that the boss 11 rotates about the contact point between the wheel 12 and the tread rail as in the related art. There is no danger that the trolley will be swung right and left to break the load balance. Further, since the bogie is not swung in a direction different from the intended direction, it is possible to improve running stability and ride comfort. Furthermore, since the wheel does not turn around the turning axis L, the dead space around the wheel is reduced, and the equipment and the like can be effectively installed and stored below the bogie.
[0029]
Further, when the traveling direction is reversed, the bogie is swung in the width direction, the distance in the tooth height direction between the rack pin 27 and the pin pinion gear 28 for driving the bogie changes, and there is a possibility that transmission of the driving force becomes impossible. Absent.
[0030]
In the above embodiment, an example of a bogie having a drive mechanism using a rack pin and a pin pinion gear has been described. However, the present invention is not limited to this, and may be applied to a driven vehicle in a vehicle driving system such as an automobile or a railway vehicle. Can be.
[0031]
Further, in the embodiment, the bearings of different types are used to make the rotational resistance between the boss and the wheel different from the rotational resistance between the wheel axle and the guide member. The resistance may have a difference. For example, in a rolling bearing, generally, the larger the nominal diameter or the nominal withstand load, the larger the rotational resistance, so that the one with the larger nominal diameter or the withstand load should be adopted at a place where a relatively large rotational resistance should be given. You may do it.
[0032]
【The invention's effect】
As described above, the caster wheel according to the first aspect of the present invention includes a wheel rotatably supported by a boss serving as an inner ring, a wheel shaft mounted at a position eccentric from the center of the boss, and A guide member rotatably supporting the shaft; and a fixing member rotatably supporting the guide member. Since the wheel shaft is rotated to offset the wheel with respect to the guide member, the traveling direction is reversed. When running, the wheels do not swing in the left and right direction. In addition, even when the vehicle descends on a steep slope, the vehicle can stably travel without being in the reverse caster state. Furthermore, the structure is very simple and maintenance is easy.
[0033]
In addition, since the rotational resistance between the boss and the wheel is different from the rotational resistance between the wheel axle and the guide member, when starting to move from a stationary state, the wheel axle with less rotational resistance rotates by rotating. Wheel eccentricity takes place. Further, the amount of eccentricity can be reliably obtained.
[0034]
Further, since the boss and the wheel are supported by a sliding bearing and the wheel axle and the guide member are supported by a rolling bearing, when the running direction is changed, the rolling bearing is used instead of the sliding bearing. Since the support has a smaller frictional resistance, the eccentricity can first be surely executed. Further, at the time of offsetting, there is no need to rotate around the rotation axis L, so that no extra space is required around the periphery.
[0035]
Further, since the diameter of the bearing rotatably supporting between the boss and the wheel is larger than the diameter of the bearing rotatably supporting between the wheel axle and the guide member, the diameter of the wheel axle having a smaller bearing diameter is reduced. In this case, the rotation resistance is smaller, and the wheel rotates first. Therefore, when the traveling direction is changed, the eccentricity of the wheel can be surely executed first.
[0036]
In addition, since the guide member has a stopper that regulates a turning range with respect to the fixed member, a turning angle of the guide member is restricted, and stable running of the caster wheels can be realized without the wheels turning unnecessarily. .
[0037]
In addition, since the wheels have grooves on the outer periphery, they can be securely engaged with the tread rails, and power loss can be reduced.
[0038]
A wheel rotatably supported by a boss serving as an inner ring; a wheel shaft mounted at a position eccentric from the center of the boss; a guide member rotatably supporting the wheel shaft; And a caster wheel having a fixed member that supports the wheel as possible, and a caster wheel that offsets the wheel with respect to the guide member by rotating the wheel shaft. There is no danger of swinging in the direction and causing collapse of the load. In addition, even when descending on a steep slope, the vehicle does not enter the reverse caster state, so that stable traveling can be realized.
[0039]
Further, since the caster wheels run on the rails and include a drive pinion gear that meshes with a pin rack rail arranged along the rails, the caster wheels can slide even on a bogie that runs on the rails. And can be driven reliably. In addition, stable running can be realized without slipping when climbing or descending a steep slope. Further, since the bogie does not swing in the left-right direction, the pinion gear, the pin rack rail and the like are not damaged.
[0040]
Further, since the caster wheel has a groove on the outer periphery and travels while engaging with a convex portion formed on the rail tread surface, power loss can be reduced. Also, stable running can be realized without falling off the wheel even when descending a steep slope. Furthermore, even if a load is applied to the bogie, the wheels can be easily offset, and the wheels do not rotate around the turning axis, so that no extra space is required around the rail.
[Brief description of the drawings]
FIG. 1 is a partially cutaway side view showing an embodiment of a caster wheel according to the present invention.
FIG. 2 is a vertical sectional view of the caster wheel.
FIG. 3 is a partially cutaway side view showing an offset state of the caster wheel.
FIG. 4 is a longitudinal sectional view showing an offset state of the caster wheel.
FIG. 5 is an exploded perspective view of the caster wheel.
FIG. 6 is a main part front view showing another embodiment of the caster wheel of the present invention.
FIG. 7 is a perspective view showing an example of a drive mechanism of a bogie provided with caster wheels according to the present invention.
FIG. 8 is a side view of the carriage.
FIG. 9 is a side view showing an example of a conventional caster wheel.
FIG. 10 is a bottom view showing a turning state of a conventional caster wheel.
[Explanation of symbols]
Reference Signs List 10 caster wheel 11 boss 12 wheel 13 wheel shaft 14 guide member 15 thrust bearing 16 fixing member 17 bearing 18 bearing 19 stopper 20 tread rail

Claims (9)

A wheel rotatably supported by a boss that is an inner ring, a wheel axle mounted at a position eccentric from the center of the boss, a guide member rotatably supporting the wheel axle, and a rotatable guide member. A caster wheel, comprising: a fixed member that supports the wheel; and the wheel shaft is rotated to offset the wheel with respect to the guide member. The caster wheel according to claim 1, wherein a rotational resistance between the boss and the wheel is different from a rotational resistance between the wheel shaft and the guide member. The caster wheel according to claim 1 or 2, wherein a portion between the boss and the wheel is supported by a slide bearing, and a portion between the wheel shaft and the guide member is supported by a rolling bearing. 3. The bearing according to claim 1, wherein a diameter of a bearing rotatably supporting between the boss and the wheel is larger than a diameter of a bearing rotatably supporting between the wheel shaft and the guide member. Castor wheels as described. The caster wheel according to any one of claims 1 to 4, further comprising a stopper that regulates a turning range of the guide member with respect to the fixed member. The caster wheel according to any one of claims 1 to 4, wherein the wheel has a groove on an outer periphery. A wheel rotatably supported by a boss that is an inner ring, a wheel axle mounted at a position eccentric from the center of the boss, a guide member rotatably supporting the wheel axle, and a rotatable guide member. A truck provided with caster wheels, comprising: a fixed member that supports the caster wheels; and caster wheels that offset the wheels with respect to the guide members by rotating the wheel shaft. The bogie provided with caster wheels according to claim 7, wherein the caster wheels include a drive pinion gear that runs on a rail and meshes with a pin rack rail disposed along the rail. . The bogie provided with caster wheels according to claim 7, wherein the caster wheels have a groove on an outer periphery and run while engaging with a convex portion formed on a rail tread surface.

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