JP5522656B2 - Wheel mounting structure for twin-wheel type stroller and stroller equipped with the structure - Google Patents

Description

The present invention relates to a wheel mounting structure for a twin-wheel stroller and a stroller equipped with the structure.
In this specification, “front” refers to the traveling direction of the stroller in a normal state, and “rear” refers to the opposite.

2. Description of the Related Art Conventionally, a twin-wheel stroller has an axle holding portion that holds an axle having wheels rotatably attached to both ends, and the axle holding portion is attached to a leg frame.
In the twin-wheel baby stroller having such a structure, as a means for mitigating vibrations transmitted to the frame during traveling, the axle holding part is installed so as to be movable up and down with respect to the frame, and a spring is installed in the vertical movement part. (See, for example, Patent Document 1).

Further, in a stroller equipped with twin-wheel type wheels, the front wheels are generally attached so as to be able to turn 360 ° horizontally, and the rear wheels are generally attached so as not to turn. This is because the front wheels can be turned horizontally to improve the steering performance, and the rear wheels are prevented from turning so as to maintain the straight running performance. The rear wheel generally has a structure in which the axle holding portion is inserted and fixed to the rear leg frame.
In order to improve the straight running stability, it has been proposed that the inner ring diameter of the twin wheels is smaller than the outer ring diameter so that the front portions of the left and right twin wheels face inward, that is, toe-in (for example, Patent Document 2).

Japanese Utility Model Publication No. 61-81471 Japanese Patent Laid-Open No. 2002-234306

The performance required for a stroller is that vibrations are suppressed even when traveling on an uneven road surface as well as a flat road surface, and stable straight traveling performance is ensured.
In this regard, in the above-described conventional stroller, a buffer member such as a spring is provided for vibration suppression, and a toe-in arrangement is provided for straight-running stability.

However, there is a problem that the above-described structure does not necessarily achieve vibration suppression and straight running stability sufficiently. Hereinafter, this point will be described in detail.
<Problem of vibration suppression>
The structure for absorbing vibration by installing the buffer member is a structure for absorbing vibration caused by unevenness of the traveling path. Therefore, vibration should not occur in the first place on a flat road. However, in the process of the development of a better stroller by the inventor, there was a phenomenon in which an unknown cause of vibration occurred when a stroller equipped with a buffer member was run on a flat road. The inventor conducted research to find out the cause of this problem, and ascertained that this was caused by the tire shapes of the inner and outer wheels constituting the twin wheels. This point will be described with reference to FIGS.
15 and 16 are schematic diagrams for ease of explanation, and the inner and outer rings are shown with the inner and outer rings arranged side by side, and the centers of the inner and outer rings are connected by a line corresponding to the axle. Is.

  As shown in FIG. 15, it is assumed that the inner ring and the outer ring have an oval shape instead of a perfect circle. In this case, when the wheel rotates, the position of the axle from the road surface changes vertically. At this time, as shown in FIG. 15, if the inner ring and the outer ring coincide with each other when viewed from the direction orthogonal to the axle, that is, if they overlap completely, the inner and outer rings move up and down at the same time, and the axle keeps horizontal and moves up and down. Will do. This state is the same as if traveling on an uneven road surface, and the vibration generated at that time can be moderated to some extent by the buffer member.

  However, since the inner ring and the outer ring actually rotate independently, it is normal that the inner ring and the outer ring do not match when viewed from the direction orthogonal to the axle. In this case, as shown in FIG. And the outer ring move up and down separately, and the axle swings with both ends up and down. The vibration generated by this is accompanied by a roll, and is not the vibration planned in the conventional example that merely assumes vertical movement, and cannot be suppressed by a conventional buffer member.

As described above, when the shape of the wheel is not a perfect circle, vibration that has not been assumed conventionally occurs. By the way, there are cases where the shape of the wheel is not a perfect circle as follows.
According to a certain manufacturing method, when inserting a tire into a wheel, the tire is pushed from the inside with a plurality of claws (for example, five claws). For this reason, the part pushed and spread by the nail will protrude slightly, and the tire may not be a perfect circle but may be a substantially pentagon. In the case of such a pentagonal tire, the same phenomenon occurs as in the case of the above-described ellipse.

The cause of the vibration that occurs when the inner and outer tires are not perfect circles is that the distance from the center to the grounding position of the inner and outer wheels does not match at each moment, and the axle swings. Even if the shape of the wheel is a perfect circle, for example, when driving on a gravel road, the same vibration will occur even if the inner ring is stepping on a pebble but the outer ring is not stepping on. . However, in the past, when driving with a stroller on a gravel road, there was a feeling that some vibration was accepted by the user as a matter of course, and measures against this kind of vibration were overlooked It is.
A problem to be solved by the present invention is to obtain a comfortable baby stroller that does not generate vibration by preventing vibration generated during traveling as much as possible, regardless of whether it is caused by the shape of the tire itself.

<Problem of straight running stability>
In a twin-wheel type stroller, as described above, the front wheels are generally installed so as to be able to turn 360 ° horizontally, and the rear wheels are generally designed not to turn horizontally. The reason for preventing the rear wheels from turning horizontally is to ensure straight running performance.
FIG. 17 is an explanatory view schematically showing the installation portion of the rear wheel, and shows a state in which the rear wheel is viewed in plan. The support part for supporting the rear wheel and the rear leg frame are joined. As shown in FIG. 17 (a), this joined part is usually installed with the rear wheel facing directly in front, for example, a rivet or the like. It is trying to fix with.

However, in the state after the frame is assembled, the rear leg frame is not correctly facing the front or the hole of the fixing rivet is displaced, so that the support frame and the rear leg frame are θ as shown in FIG. If it is arranged with a shift of 0 °, the rear wheels will not face directly in front, which will impair straight running stability. Further, if the vehicle is forced to go straight in spite of the state where the rear wheels are not facing directly in front, the rear wheels are dragged without rotating smoothly, and the tires are worn away.
For this reason, the rear leg frame is managed and manufactured so as to face right in front. However, there are cases where the rear leg frame does not face right in front due to errors during assembly.
Therefore, another problem to be solved by the present invention is to obtain a stroller that does not impair the straight running stability even if the frame axis does not face directly in front.

(1) The wheel mounting structure of the two-wheeled baby stroller according to the present invention is configured to hold the axle on which the inner and outer wheels of the two wheels are rotatably attached, so that the inner wheel held on the axle and the The outer ring can move in the reverse direction.

(2) Further, in the above (1), the swing angle is 3 ° or more each in the vertical direction.

(3) Further, in the above (1) or (2), it includes an axle holding member that holds the axle, and a support member that is attached to a leg frame and supports the axle holding member, By forming a gap between the axle holding member and the support member, the axle holding member can swing with respect to the support member.

(4) Further, in any of the above (1) to (3), the axle holding member is attached to the support member so as to be movable up and down, and between the axle holding member and the support member. It is characterized in that an elastic body is set.

(5) Further, in any one of the above (1) to (4), the axle holding member is provided with a stopper that locks the inner ring and the outer ring and stops the rotation of the inner ring and the outer ring. It is characterized by.

(6) Further, in the above-described (3) to (5), the support member provided on the rear wheel side is attached to the rear leg frame so as to be horizontally rotatable by a predetermined angle. It is characterized by.

(7) Further, in the above (6), the rotation angle is set in the range of 3 ° to 5 ° to the left and right.

(8) Further, in any of the above (5) to (7), the support member is inserted into the hole formed in the support member by inserting the end of the rear leg frame into the rear leg frame. The axially orthogonal cross-sectional shape of the end portion of the rear leg frame is a shape having arcuate portions in the front and rear, and the support member has an end portion of the rear leg frame. A hole into which the part can be inserted is provided, and the shape of the hole includes an arcuate part that follows the arcuate part formed before and after the end of the rear leg frame.

(9) A stroller according to the present invention includes the wheel mounting structure for a twin-wheel stroller according to any one of (1) to (8) above.

  In the present invention, the inner ring and the outer ring held on the axle can be moved in the upside down direction by holding the axle on which the inner and outer rings of the two wheels are rotatably mounted so as to swing. For example, vibration caused by the inner ring and / or outer ring not being a perfect circle can be absorbed by the swinging of the axle, and a comfortable stroller with less vibration can be realized.

It is explanatory drawing of the frame of the stroller which concerns on one embodiment of this invention, and is a figure which shows the state which looked at the frame from diagonally forward. It is explanatory drawing of the frame of the stroller which concerns on one embodiment of this invention, and is a figure which shows the state which looked at the frame from back diagonally. It is a figure which shows the state which looked at the A section enclosed with the circle of FIG. 2 from back. It is explanatory drawing of the attachment structure of a wheel, and is the figure which showed only the components of the attachment part in the state seen from the arrow AA direction in FIG. It is a top view of FIG. 4, and is a figure including the enlarged view which expands and shows a part. It is a bottom view of FIG. 4, and is a figure including the enlarged view which expands and shows a part. It is sectional drawing which follows the arrow BB line of FIG. It is a top view of the attaching part of a rear wheel, and is a figure containing the enlarged view which expands and shows a part. It is operation | movement explanatory drawing of the attaching part of a rear wheel, and is a figure containing the enlarged view which expands and shows a part. It is operation | movement explanatory drawing of the attaching part of a rear wheel. It is operation | movement explanatory drawing of the attaching part of a rear wheel. It is a top view of the attaching part of a rear wheel. It is a figure containing the enlarged view which expands and shows a part. It is explanatory drawing explaining the effect | action of the attaching part of a rear-wheel, and is a figure containing the enlarged view which expands and shows a part. It is explanatory drawing explaining the effect | action of the attaching part of a rear-wheel, and is a figure containing the enlarged view which expands and shows a part. It is a figure explaining the subject of this invention. It is a figure explaining the subject of this invention. It is a figure explaining the subject of this invention.

  The overall structure of the frame of the stroller 1 provided with the wheel mounting structure of the present invention will be outlined based on FIGS. The frame of the stroller 1 according to the present embodiment includes a rear leg 3 consisting of a pair of left and right rear limbs, a front leg 5 consisting of a front heel, and a push bar 7 connected to the front leg 5 via a connecting member 4. The upper end portion of the rear leg 3 and the lower portion of the push rod 7 are rotatably connected by a connecting portion (not shown).

The upper part of the push bar 7 and the lower part of the rear leg 3 are connected by a first cross bar 9 that intersects at a substantially central part. Further, the lower part of the rear leg 3 and the lower part of the front leg 5 are also connected by a second crossing bar 11 that intersects at a substantially central part. These first and second crossing ridges 17 and 19 are connected to each other so as to be rotatable at the crossing portions, and can move so that the respective ridges are separated from each other. Due to the movement of the first and second cross rods 17 and 19, a pair of left and right rear rods, front rods and push rods 7 are separated by a predetermined distance in the use state, and they are close to each other in the folded state.
A seat rod 13 is provided to hold the seat from the lower part of the rear leg 3 to the upper part of the front leg 5.

  A rear wheel 15 and a front wheel 17 are attached to lower ends of the rear leg 3 and the front leg 5, respectively. Both the rear wheel 15 and the front wheel 17 have a double wheel structure, and an inner ring 19 and an outer ring 21 are rotatably attached to both ends of the axle 23. The front wheel 17 is attached so as to be turnable in the horizontal direction, and the rear wheel 15 is attached so as to be rotatable by a predetermined angle in the horizontal direction.

The mounting structure of the rear wheel 15 will be described with reference to FIG. 3 showing the enlarged portion A of FIG. 2 and FIGS. 4 to 14 which are explanatory diagrams of parts of the mounting portion.
The mounting structure of the rear wheel 15 includes an axle holding member 25 that holds an axle 23 having an inner ring 19 and an outer ring 21 attached to end portions, and a support member 27 that is connected to the rear leg 3 and supports the axle holding member 25. It is configured with. In FIGS. 3 to 14, the axle holding member 25 is shown in a light color to clarify the distinction between components.

The support member 27 is provided adjacent to the rear leg insertion hole 29 and the rear leg insertion hole 29 into which the end of the rear leg 3 is inserted (see FIGS. 5 and 6), and is a part of the axle holding member 25. Is provided with an insertion chamber 31 (see FIG. 7) into which the head can be moved up and down.
The rear leg insertion hole 29 has arcuate surface portions 29a on the front and rear sides, and has flat portions 29b on both sides between the arcuate surface portions 29a. The insertion chamber 31 has an opening at the bottom, a ceiling surface 33 (see FIG. 5) is provided on the top, and the flat cross section has a substantially U-shape opening at the rear (see FIG. 6). Guide grooves 35 extending vertically are formed on both front sides of the insertion chamber 31. In addition, on the side surface of the insertion chamber 31, there is provided an elongated circular opening 37 that extends in the vertical direction into which the axle 23 is inserted (see FIG. 4).

At the end of the rear leg 3 to be inserted into the rear leg insertion hole 29, an end pipe 41 (see FIG. 5) made of resin and an elliptical pipe 39 (see FIG. 13) constituting the rear leg 3 are, for example, rivets. It will be fixed at. The end member 41 has substantially the same shape as the rear leg insertion hole 29, the front and rear are arcuate surfaces, and both side surfaces are flat.
As shown in FIG. 5, in the state where the end member 41 is inserted into the insertion hole, a gap S1 is formed in both of the flat portions 29b. The member 27 is rotatable in a horizontal direction by a predetermined angle (3 ° to 5 ° to the left and right).
Yes.

  Since the rear leg insertion hole 29 and the end member 41 are in contact with each other with an arcuate surface before and after that, both can be smoothly rotated.

A portion of the axle holding member 25 that is inserted into the insertion chamber 31 has a rectangular shape similar to that of the insertion chamber 31 (see FIG. 6), and an axle insertion hole 45 into which the axle 23 is inserted into the rectangular portion 43. Is provided (see FIG. 4). On the front part of the rectangular part 43, protruding ridges 47 projecting on both sides are formed, the protruding ridges 47 are inserted into the guide grooves 35 of the insertion chamber 31, and the axle holding member 25 moves up and down along the guide grooves 35. It can be moved.
As shown in FIG. 7, a spring 49 is mounted between the rectangular portion 43 and the ceiling surface 33 of the axle holding member 25, and a cushion rubber 51 is installed above the spring 49. These springs 49 and cushion rubber 51 serve as cushioning materials to alleviate vibrations in the vertical direction of the wheel.

  As shown in FIG. 6, a gap S2 and a gap S3 larger than the gap S2 are formed between the wall of the insertion chamber 31 and the rectangular portion 43. Since the gaps S2 and S3 are formed, the axle holding member 25 can swing with respect to the support member 27, and therefore the axle 23 can swing with respect to the support member 27. It is the gap S2 that defines the swing angle of the axle holding member 25 with respect to the support member 27. The swing angle is preferably 3 ° or more, and the gap S2 is set so that such a swing angle can be secured.

Two bracket portions 53 are provided behind the rectangular portion 43 so as to protrude from the rectangular portion 43 at a predetermined interval (see FIG. 6). A stopper member 55 is rotatably mounted so as to be sandwiched between the two bracket portions 53.
The stopper member 55 is inserted into an operation lever 57 that is operated by a foot, a projection 59 that is locked to the spoke portion of the wheel to stop the rotation of the wheel, and a hole 61 formed in the two bracket portions 53. The rotating shaft 63 is provided (see FIG. 4).
The stopper member 55 is supported by the rotation shaft 63 and can rotate in the direction of the arrow in FIG. And when it rotates below, the projection part 59 is comprised so that a wheel may stop and a rotation of a wheel may be stopped.
The stopper member 55 is provided with a protrusion 65. When the vehicle travels, the protrusion 65 is locked in a hole 67 formed in the bracket portion 53, and the position is maintained. When the operation is stopped, the protrusion 65 is engaged with the hole 69 formed in the bracket portion 53 and the position is maintained.
By attaching the stopper member 55 to the axle holding member 25, even if the axle holding member 25 moves up and down, the relative position between the stopper member 55 and the wheel does not change, so that the protrusion 59 of the stopper member 55 is securely attached to the wheel. It can be locked.

  Although the above description is about the rear wheel 15, a similar structure can be adopted for the front wheel 17, and a structure in which the axle 23 of the front wheel 17 can swing with respect to the support member 27 can be adopted. is there. However, it is not necessary to provide the stopper member 55 for the front wheel 17.

  Next, the operation of the present embodiment configured as described above will be described. In describing the operation, the swinging of the axle 23, which is a feature of the present embodiment, will be described first, and then the horizontal rotation of the support member 27 will be described.

<Axle swing>
As shown in FIGS. 6 and 8, gaps S 2 and S 3 are formed between the support member 27 and the axle holding member 25, and the axle holding member 25 can swing with respect to the support member 27. . Therefore, the axle held by the axle holding member 25 can swing at an angle of θ 2, and as shown in FIGS. 9 and 10, the inner ring 19 side is higher than the outer ring 21 side, as shown in FIGS. Thus, the outer ring 21 side can be higher than the inner ring 19 side.
If the shape of the inner ring 19 and / or the outer ring 21 is not a perfect circle, the axle holding member 25 swings together with the axle 23 during traveling due to the shape, but the swing is independent of the support member 27. And is not transmitted to the support member 27 and hence no vibration is transmitted to the rear leg 3. That is, if the axle holding member 25 cannot swing with respect to the support member 27 as in the prior art, the vibration caused by the shape of the wheel is directly transmitted to the rear leg 3 and the frame vibrates. In this embodiment, the axle holding member 25 swings with respect to the support member 27, so that the swing of the axle 23 is not transmitted to the support member 27.

  The swing of the axle 23 is preferably set so that the swing angle θ2 is 3 ° on one side and 6 ° or more as a whole.

<About horizontal rotation>
FIG. 12 is a plan view of one rear wheel portion, and this state is a state in which the rear wheel 15 is straight with respect to the traveling direction. 13 shows a state in which the end member 41 is horizontally rotated counterclockwise by θ1 ° from the state shown in FIG. 12, and FIG. 14 shows a horizontal state by θ1 ° clockwise from the state shown in FIG. The rotated state is shown.

Thus, in the present embodiment, the end member 41 installed at the end of the rear leg 3 can be horizontally rotated with respect to the support member 27 by a predetermined angle. Therefore, even if the rear wheel 15 is not directed straight in the traveling direction with the support member 27 inserted into the end portion of the rear leg, the stroller 1 is traveled to make a straight correction. By correcting the direction of the rear wheel 15 in a straight direction, the rear wheel 15 rotates smoothly and does not wear out.
Moreover, the rear wheel 15 is not rotatable 360 ° like the front wheel, but can be rotated only by a predetermined angle (an angle of 3 ° to 5 ° in one side direction), and the straight traveling performance is not impaired.

  As described above, according to the present embodiment, for example, the swing of the axle 23 caused by the shape of the wheel can be prevented from being transmitted to the rear leg 3, and the vibration caused by the shape of the wheel can be prevented. Further, even in a state where the rear wheel 15 cannot be installed straight due to an assembly error of the rear leg 3, it is possible to ensure a straight traveling stability and to prevent one-side wear of the rear wheel 15.

In the above-described embodiment, as an example of a structure in which the axle 23 can swing independently with respect to the rear leg 3, the axle holding member 25 that holds the axle 23 is fixed to the support member 27 that supports the axle 23. However, the present invention is not limited to this, and any other structure may be used as long as the axle 23 is installed so as to be able to swing independently with respect to the rear leg 3. It may be a structure.
For example, a swingable gap is not provided between the axle holding member 25 and the support member 27 so that the support member 27 can swing relative to the rear leg 3 at the connecting portion between the support member 27 and the rear leg 3. The structure which installs may be sufficient.
However, in the present embodiment, since the axle holding member 25 can be swung with respect to the support member 27, the swinging portion is provided in the vicinity of the axle 23. Even if the gap is reduced, the swing angle can be increased, which is preferable.

  Further, in the present embodiment, as a structure in which the support member 27 is installed so as to be horizontally rotatable with respect to the rear leg 3 by a predetermined angle, the cross-sectional shape of the insertion portion between the rear leg end portion and the support member 27 is set to the front and rear. Although the example of the shape which has a curved part and has the plane part 29b on both sides was given, this invention is not limited to this, The shape which can rotate the support member 27 only a predetermined angle with respect to the rear leg 3 Any other shape may be used.

The wheel mounting structure of the present embodiment shows an example in which the axle 23 is swingable and the support member 27 is horizontally rotatable with respect to the rear leg 3. However, the axle 23 is swung. The possible structure and the structure in which the support member 27 can be horizontally rotated with respect to the rear leg 3 can be independently mounted on the stroller.
Therefore, the structure of the stroller on which only the structure in which the support member 27 is horizontally rotatable with respect to the rear leg 3 can be expressed as follows.
An axle holding member 25 that holds the axle 23 and a support member 27 that is attached to the rear leg frame and supports the axle holding member 25. The support member 27 is horizontally oriented at a predetermined angle with respect to the rear leg frame. A structure for mounting a wheel of a two-wheeled baby stroller, characterized in that it is rotatably mounted.

DESCRIPTION OF SYMBOLS 1 Stroller 3 Rear leg 4 Connecting member 5 Front leg 7 Push rod 9 First crossing rod 11 Second crossing rod 13 Seat rod 15 Rear wheel 17 Front wheel 19 Inner ring 21 Outer wheel 23 Axle 25 Axle holding member 27 Support member 29 Rear leg insertion hole 29a Circle Arc-shaped surface portion 29b Planar portion 31 Insertion chamber 33 Ceiling surface 35 Guide groove 37 Opening portion 39 Pipe 41 End member 43 Rectangular portion 45 Axle insertion hole 47 Projection portion 49 Spring 51 Cushion rubber 53 Bracket portion 55 Stopper member 57 Operation lever 59 Projection Part 61 hole 63 rotating shaft 65 protrusion 67 hole 69 hole

Claims (7)

The inner ring and the outer ring held on the axle can be moved in the upside down direction by holding the axle on which the inner and outer rings of the two wheels are rotatably mounted so as to be swingable.
An axle holding member that holds the axle and is provided with a bracket portion; and a support member that is attached to a leg frame and supports the axle holding member;
The support member includes an insertion hole into which an end portion of the leg frame is inserted, and an insertion chamber provided adjacent to the insertion hole into which a part of the axle holding member is inserted.
The axle holding member has a portion inserted into the insertion chamber;
Allowing the axle holding member to swing with respect to the support member by forming a gap between a portion of the axle holding member inserted into the insertion chamber and the insertion chamber of the support member;
2. A wheel mounting structure for a two-wheel stroller, wherein a stopper for stopping the rotation of the inner ring and the outer ring by stopping the rotation of the inner ring and the outer ring is provided on the bracket portion of the axle holding member.   2. The wheel mounting structure for a double-wheeled baby stroller according to claim 1, wherein the swing angle is 3 [deg.] Or more in the vertical direction. The axle holding member is vertically movable while being supported by the supporting member, to claim 1 or 2, characterized in that it has established an elastic body between the supporting member and the axle holding member Mounting structure of the wheel of the described two-wheel type baby stroller.   4. The twin-wheel stroller according to claim 1, wherein the support member provided on a rear wheel side is attached to the rear leg frame so as to be horizontally rotatable by a predetermined angle. 5. Wheel mounting structure.   5. The structure for mounting a wheel of a double-wheeled baby stroller according to claim 4, wherein the rotation angle is set in a range of 3 [deg.] To 5 [deg.] To the left and right. The support member is installed in the rear leg frame so as to be horizontally rotatable by inserting an end of the rear leg frame into an insertion hole formed in the support member, and the end of the rear leg frame The support member is provided with an insertion hole into which an end of the rear leg frame can be inserted , and the shape of the insertion hole is the rear leg frame. The wheel mounting structure for a double-wheeled baby stroller according to claim 4 or 5, further comprising an arc-shaped portion that follows the arc-shaped portion formed before and after the end portion.   A stroller comprising the wheel mounting structure of the twin-wheel stroller according to any one of claims 1 to 6.

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