JP7095191B1 - Tire automatic air supply device - Google Patents

Abstract

An object of the present invention is to provide a highly reliable and compact automatic tire air supply device in which damage to a piston shaft or the like is unlikely to occur. An automatic tire air supply device (100) includes a cylinder (108) configured such that an external space (106) above a piston (104) always communicates with the outside, and a Due to the differential pressure between the negative pressure in the intermediate space 110 and the pressure in the outer space 106, air flows from the outer space 106 into the intermediate space 110, restricting the flow of air from the intermediate space 110 to the outer space 106 during the descent process. and an exterior body 116 that forms a tire-side space 114 between the asymmetrical ventilation portion 112 configured to allow air to flow from the intermediate space 110 to the tire-side space 114, It has a cylinder check valve 118 that blocks the reverse air flow, and an elastic member 120 that biases the piston 104 downward. [Selection drawing] Fig. 3

Description

The present invention relates to an automatic tire air supply device for automatically supplying air into tires of bicycles, wheelchairs, motorcycles and the like.

It is desirable that bicycles and the like be used under appropriate tire pressure. However, since air leaks little by little from the surface of the tire tube, valves, etc., the air pressure of the tire decreases over time. If this is left unattended, the frictional resistance between the tire and the ground surface will increase, and tire wear and puncture will easily occur. Maintenance is performed to supply air to the tires by a manual air pump or electric compressor in order to maintain the tire pressure properly. Further, there is known an automatic tire air supply device that is mounted on a valve stem of a tire instead of the original valve to automatically supply air to the tire (see, for example, Patent Documents 1 to 3).

The tire automatic air supply device disclosed in the first embodiment (FIG. 4 and the like) of Patent Document 1 includes a cylinder housed in a valve stem, a piston slidable in the cylinder, and a lower side of the piston (tire diameter). The piston shaft attached to the outside in the direction), the shock absorber attached to the lower end of the piston shaft, the elastic body that urges the piston shaft and the piston downward together with the shock absorber, and the elastic body attached to the inside of the upper part of the cylinder from the outside. A first check valve that allows the inflow of air into the cylinder and blocks the flow of air in the opposite direction, and a first check valve that is mounted on the outside of the upper part of the cylinder and allows the inflow of air from the cylinder between the cylinder and the valve stem. It is equipped with a second check valve that blocks the flow of air in the opposite direction. When the tire tube contains a sufficient amount of air, the shock absorber is separated from the tire tube and the piston does not move even if the tire rolls. On the other hand, when the amount of air in the tire tube decreases to some extent, when the tire rolls and the shock absorber comes close to the ground, the shock absorber comes into contact with the tire tube and resists the urging force of the elastic body. The shock absorber, piston shaft and piston move upward. As a result, the air in the cylinder above the piston is pressurized, air flows from the cylinder between the cylinder and the valve stem via the second check valve, and air is supplied to the tire. When the tire rolls further and the shock absorber comes to a position away from the ground, the piston moves outward in the radial direction due to the urging force of the elastic body. As a result, the pressure inside the cylinder above the piston is reduced, and air flows into the cylinder from the outside through the first check valve.

Further, the automatic tire air supply device disclosed in Example 4 (FIG. 25, etc.) of Patent Document 1 includes a second check valve attached to a piston. This second check valve allows the inflow of air from the portion above the piston in the cylinder to the portion below the piston and blocks the flow of air in the opposite direction. In addition, a vent is formed on the side of the lower part of the cylinder. Further, a swing rod is attached between the shock absorber and the piston shaft. Unlike the tire automatic air supply device disclosed in Example 1 (FIG. 4 and the like), the check valve on the outer side of the upper part of the cylinder is not attached. Other configurations are the same as those of the tire automatic air supply device disclosed in the first embodiment (FIG. 4 and the like). In the tire automatic air supply device disclosed in the fourth embodiment, when the piston moves upward against the urging force of the elastic body, the air in the cylinder above the piston is pressurized and through the second check valve. Air flows from the upper side of the piston to the lower side of the piston. Then, when the shock absorber comes to a position away from the ground as the tire rolls, the piston moves outward in the radial direction due to the urging force of the elastic body. As a result, air flows into the valve stem from the vent at the bottom of the cylinder and is supplied to the tire. At this time, the pressure inside the cylinder above the piston is reduced, and air flows into the cylinder from the outside through the first check valve. The automatic tire air supply device disclosed in Patent Document 1 is configured to be attached to the valve stem by a cap nut for attaching a normal valve, and is compact because most of it is housed in the valve stem. be.

The automatic tire air supply device disclosed in Patent Document 2 is configured such that the lower part of the cylinder is screwed into the screwed portion of the valve stem instead of the cap nut. Further, air is supplied into the tire via the hollow piston shaft. In Example 1 of Patent Document 1, when the piston moves upward against the urging force of the elastic body, the air in the cylinder above the piston is pressurized and the air is supplied to the tire. It is the same as the tire automatic air supply device disclosed in.

Further, the automatic tire air supply device disclosed in Patent Document 3 is provided with a screw portion such as a cap nut, and the lower end of the first cylinder is attached to this screw portion. Air is supplied into the tire tube through a gap or groove between the hollow rocking rod and the second cylinder. Further, a friction member is mounted in a hollow swing rod, and a piston shaft is mounted on the friction member. When a force exceeding a predetermined acceleration is applied to the swing rod via the shock absorber, the friction member slides with respect to the piston shaft (or swing rod), and the swing rod and the piston shaft are less likely to be damaged. There is. It should be noted that when the piston moves upward against the urging force of the elastic body, the air in the cylinder above the piston is pressurized and the tire is supplied with air, according to Example 1 of Patent Document 1 and Patent Document. It is the same as the tire automatic air supply device disclosed in 2.

Japanese Unexamined Patent Publication No. 2012-02613 Japanese Patent No. 5459725 Japanese Patent No. 5920756

By the way, the piston stroke may become longer depending on the degree of tire air reduction and the size of the tire. Therefore, the piston may interfere with the check valve or the like on the upper part of the cylinder. This may damage the check valve, its peripheral parts, or the piston shaft. If the check valve and its surroundings are damaged, it may not be possible to supply air to the tires. In addition, the tire tube may be damaged due to the damage of the piston shaft. Since most of the automatic tire air supply device disclosed in Patent Document 1 is housed in the valve stem of the tire tube, it may not be possible to adopt a long cylinder that does not interfere with the piston even if a long piston stroke is assumed. be.

On the other hand, for the automatic tire air supply device disclosed in Patent Document 2, it is possible to adopt a long cylinder that does not interfere with the piston even with a long piston stroke, but even if interference is avoided, a step on the ground or the like can be adopted. If the piston suddenly moves upward, the pressure in the cylinder above the piston temporarily becomes excessive and the piston shaft or the like may be damaged.

Further, in the automatic tire air supply device disclosed in Patent Document 3, the friction member slides with respect to the piston shaft (or the swing rod) when a force equal to or higher than a predetermined acceleration is applied to the swing rod via the shock absorber. Therefore, the swing rod and the piston shaft are less likely to be damaged, but the cylinder needs to be provided with a swing rod movement region in addition to the piston movement region, so the size increases in the longitudinal direction. There is a problem that it will end up. Further, if the sliding surface between the friction member and the piston shaft (or the swing rod) is worn and the frictional force is reduced, sufficient air supply to the tire tube may not be possible.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a highly reliable and compact automatic tire air supply device in which damage to the piston shaft and the like is unlikely to occur.

The present invention has a piston shaft that is inserted into the valve stem as a rod and is configured to be pushed upward when the tire rolls and the valve stem approaches the ground, a piston attached to the piston shaft, and a cylinder. A cylinder that is configured to slidably accommodate the piston in a shape so that the external space above the piston is always in communication with the outside, and the negative of the intermediate space below the piston in the ascending process of the piston. Asymmetric ventilation configured to allow air to flow from the external space into the intermediate space due to the differential pressure between the pressure and the pressure in the external space, limiting the flow of air from the intermediate space to the external space during the ascending process of the piston. An exterior body that accommodates the piston and forms a tire-side space that accommodates the cylinder and communicates within the tire, and allows air flow from the intermediate space to the tire-side space, and vice versa. The above problem is solved by an automatic tire air supply device including a cylinder check valve that blocks the flow and an elastic member that urges the piston downward.

As the tire rolls, the vertical posture of the automatic tire air supply device reverses when the valve stem is located near the ground and when it is farthest from the ground. However, in this application, the valve stem is located near the ground for convenience. The vertical posture of the tire automatic air supply device will be described based on the posture of the tire automatic air supply device when it is located at.

This tire automatic air supply device is configured so that the outer space above the piston always communicates with the outside. In the asymmetric vent, air flows from the external space to the intermediate space due to the difference pressure between the negative pressure in the intermediate space below the piston inside the cylinder and the pressure in the external space (atmospheric pressure) during the ascending process of the piston. It is configured to flow in. Therefore, the pressure above the atmospheric pressure does not act on the piston in the process of ascending the piston. Further, since the cylinder is housed in the exterior body, the degree of freedom in designing the cylinder is higher than that in the configuration in which the cylinder is housed in the valve stem. Therefore, it is possible to adopt a cylinder having a length such that the piston does not interfere with the member on the upper part of the cylinder even with a long piston stroke. Therefore, the piston shaft and the like are less likely to be damaged. Further, since the length of the cylinder may be long enough to correspond to the moving region of the piston, it is possible to make the design compact enough necessary and sufficient in the longitudinal direction.

The inner peripheral surface of the cylinder is composed of a lower portion on which the piston slides and an upper portion having a diameter larger than that of the lower portion and forming a gap between the piston and the inner peripheral surface of the cylinder and the piston. May form an asymmetric vent. Although this asymmetric ventilation part has a simple structure, the negative pressure in the intermediate space below the piston and the negative pressure of the piston through the gap between the upper part of the inner peripheral surface of the cylinder and the piston during the ascending process of the piston. Air flows from the external space into the intermediate space with a small resistance due to the differential pressure from the pressure (atmospheric pressure) in the upper external space. Further, in the descending process of the piston, the lower part of the inner peripheral surface of the cylinder and the piston slide to limit the air flow from the intermediate space below the piston to the outer space above the piston. can.

Further, the asymmetric ventilation portion may be a piston check valve installed on the piston.

In addition, a ventilation hole is formed in the cylinder that penetrates from the inner peripheral surface to the outer peripheral surface, and a valve member that covers the ventilation hole with an elastic tubular body is fitted in a tightly bound state on the outer peripheral surface of the cylinder to form a ventilation hole. The valve member may constitute a cylinder check valve. A cylinder check valve composed of such a vent and a valve member is simple and compact.

Further, a plurality of ventilation holes may be formed at positions separated from each other in the longitudinal direction of the cylinder. For example, if one ventilation hole is formed near the lower end of the cylinder, most of the air in the intermediate space below the piston can be supplied into the tire. Also, if other vents are formed above the bottom dead center piston, this from the external space above the piston by a manual air pump or electric compressor with the piston located at bottom dead center. Air can be supplied to the tire side space through the ventilation holes.

According to the present invention, it is possible to realize a highly reliable and compact automatic tire air supply device in which the piston shaft and the like are less likely to be damaged.

A side view showing a part of a bicycle in which the automatic tire air supply device according to the first embodiment of the present invention is attached to a valve stem. A side view showing an enlarged view of the bicycle's automatic tire air supply device and its peripheral parts. Cross-sectional view showing the structure of the tire automatic air supply device in a further enlarged manner Sectional drawing which shows the structure of the tire automatic air supply device which concerns on 2nd Embodiment of this invention. A cross-sectional view showing an enlarged view of the piston structure of the tire automatic air supply device. A cross-sectional view showing an enlarged example of another structure of the piston of the tire automatic air supply device.

As shown in FIGS. 1 and 2, the tire automatic air supply device 100 according to the first embodiment of the present invention is used by being attached to a valve stem 14 of a wheel 12 of a bicycle 10. Although the front wheel of the bicycle 10 is drawn in FIG. 1, the tire automatic air supply device 100 can also be attached to the rear wheel. As shown in FIG. 3, the automatic tire air supply device 100 is configured to be inserted into the valve stem 14 in a rod shape and pushed upward when the tire 16 rolls and the valve stem approaches the ground. The piston shaft 102, the piston 104 attached to the piston shaft 102, and the piston 104 are slidably accommodated in a tubular body, and the external space 106 above the piston 104 is configured to always communicate with the outside. Air flows from the external space 106 into the intermediate space 110 due to the difference pressure between the negative pressure of the intermediate space 110 below the piston 104 of the cylinder 108 and the pressure of the external space 106 during the ascending process of the cylinder 108 and the piston 104. The tire is located between the asymmetric ventilation portion 112 configured to limit the flow of air from the intermediate space 110 to the external space 106 in the descending process of the piston 104, and the outer peripheral surface of the cylinder 108 accommodating the cylinder 108. An exterior body 116 forming a tire-side space 114 communicating with the inside of 16, and a cylinder check valve 118 that allows air flow from the intermediate space 110 to the tire-side space 114 and blocks the reverse air flow. An elastic member 120 that urges the piston 104 downward is provided.

The wheel 12 of the bicycle 10 includes a tire 16, a tube (not shown), and a rim 18. The valve stem 14 is installed at the inner peripheral portion of the tube, passes through a through hole in the inner peripheral wall of the rim 18, and protrudes inward in the radial direction of the wheel 12. The tire may be a tubeless tire. In this case, the valve stem is installed on the rim.

The piston shaft 102 is a thin metal rod-shaped body. A swing rod 122 is attached to the lower end of the piston shaft 102. The swing rod 122 is a thin metal cylindrical body, and a part of the upper side is fitted to the lower end of the piston shaft 12, and the other part extends below the piston shaft 102. A shock absorber 124 is attached to the lower end of the swing rod 122. The shock absorber 124 is a rubber columnar body having a diameter larger than that of the swing rod 122, and has a hole formed in the center on the upper side. In this hole, the shock absorber 124 is fitted to the lower end of the swing rod 122. A protective body 126 is fitted on the outer periphery of the swinging rod 122. The protective body 126 is a rubber cylindrical body whose lower end is in contact with the upper end of the buffer body 124. The protecting body 126 extends above the swinging rod 122 and houses the piston shaft 102. A metal tubular seal tube 128 is arranged on the outer periphery of the portion near the upper end of the protective body 126. The inner diameter of the seal tube 128 is larger than the outer diameter of the protective body 126, and a gap is formed between the seal tube 128 and the protective body 126. Air is supplied from the tire side space 114 into the valve stem 14 through this gap. The seal tube 128 may be fitted on the outer periphery of the protective body 126. In this case, a groove is formed on the inner peripheral surface of the seal tube 128 along the longitudinal direction (vertical direction), and air is supplied from the tire side space 114 into the valve stem 14 through this groove. You may. A collar is formed at the upper end of the outer circumference of the seal tube 128. The upper end of the outer peripheral edge of the seal tube 128 may be an annular member separate from the seal tube and may be fitted to the seal tube on the inner circumference. Further, the annular member may be fitted with the mounting screw portion on the outer periphery. A rubber tubular seal 130 is fitted on the outer periphery of the seal tube 128.

The piston 104 is composed of a core portion 104A attached to the piston shaft 102 and an outer peripheral portion 104B. The core portion 104A is made of metal and has a tubular portion fitted to the upper end of the piston shaft 102 and a circular flange portion formed around the upper end of the tubular portion. The outer peripheral portion 104B is a rubber annular body that fits on the outer surface of the tubular portion of the core portion 104A and is in contact with the lower surface of the flange portion.

The cylinder 108 is a metal cylinder slightly longer than the radial width of the tire 16. The inner peripheral surface 132 of the cylinder 108 is composed of a lower portion 132A on which the piston 104 slides and an upper portion 132B having a diameter larger than that of the lower portion 132A and forming a gap between the piston 104. The inner peripheral surface 132 of the cylinder 108 and the piston 104 form an asymmetric ventilation portion 112. A bottom wall portion 134 is fitted to the lower end of the cylinder 108. The bottom wall portion 134 is a disk-shaped body made of metal or hard rubber. A through hole is formed in the center of the bottom wall portion 134, and the piston shaft 102 is slidably inserted through the through hole. A head 136 is fitted to the upper end of the cylinder 108. The head 136 is a metal member having a lower end portion fitted to the upper end of the cylinder 108, a flange portion formed on the upper side of the lower end portion, and a truncated cone-shaped screw portion formed on the upper side of the flange portion. It is configured. A through hole is formed in the center of the head 136. A cap 138 is screwed into the threaded portion of the head 136. The cap 138 is a rubber member having a truncated cone shape and has a through hole formed in the center of the upper surface portion. The outer space 106 above the piston 104 in the cylinder 108 is configured to always communicate with the outside (atmosphere) through the through hole of the cap 138 and the through hole of the head 136. The cylinder 108 pistons until the air in the tire 16 is reduced and the shock absorber 124 is in contact with the inner peripheral surface of the radial inner portion of the tube of the tire 16 (in the case of a tubeless tire, the radial inner portion of the tire). Even if the 104 rises, the elastic member 120 has a length that does not compress the elastic member 120 to the limit and the piston 104 does not interfere with the head 136.

Vent holes 140 and 142 penetrating from the inner peripheral surface to the outer peripheral surface are formed in the cylinder 108. A valve member 144 covering the ventilation holes 140 and 142 with an elastic cylindrical body is fitted to the outer peripheral surface of the cylinder 108 in a tightly bound state. These ventilation holes 140 and 142 and the valve member 144 constitute the cylinder check valve 118. The ventilation hole 140 is formed at a position close to the bottom surface of the cylinder 108 (the upper surface of the bottom wall portion 134). On the other hand, the ventilation hole 142 is the lower portion 132A of the cylinder 108, and is formed at a position above the piston 104 at the bottom dead center position. The cylinder check valve 118 also serves as two cylinder check valves, and is provided with substantially two cylinder check valves.

The exterior body 116 is a metal tubular body having a diameter larger than that of the cylinder 108, and is arranged coaxially with the cylinder 108. A mounting screw portion 146 is fitted to the lower end of the exterior body 116. The mounting screw portion 146 is a tubular body made of metal, and a female screw is formed on the inner peripheral surface. The tire automatic air supply device 100 is fitted by screwing (instead of a cap nut) to the male screw of the valve stem 14 of the wheel 12 by means of the mounting screw portion 146. Inside the exterior body 116, the upper end of the mounting screw portion 146 is in contact with the lower surface of the flange portion of the seal tube 128. The seal tube 128 is attached to the mounting screw portion 146 at the crossguard portion. A vertical gap is formed between the upper surface of the flange of the seal tube 128 and the lower end of the cylinder 108. The upper end of the exterior body 116 is located at a position lower than the upper end of the cylinder 108, and has a vertical gap between the upper end and the flange portion of the head 136. An upper annular member 150 is fitted inside the upper end of the exterior body 116. A cylinder 108 is fitted inside the upper annular member 150. The cylinder 108 is supported by the exterior body 116 via the upper annular member 150.

The elastic member 120 is a coil spring and is mounted between the piston 104 and the head 136. The core portion 104A of the piston 104 and the lower end portion of the head 136 are spring seats. In the first embodiment, the elastic member 120 is in direct contact with the piston 104 to urge the piston 104 downward. The piston shaft 102 sways so that the piston 104 is urged by the elastic member 120 and held at the bottom dead center (the position where it abuts on the bottom wall portion 134) under normal conditions (when the tire 16 has sufficient air). Dimensions such as the moving rod 122 are designed. Further, the dimensions of the piston shaft 102, the swing rod 122, and the like are designed so that the piston 104 reciprocates slightly in the vicinity of the bottom dead center under normal conditions. When a person is on the tire 16, the portion of the tire 16 near the ground is pressurized by the weight of the person and the bicycle 10, and the inner peripheral surface of the tube or the tire is deformed inward in the radial direction. Therefore, the positional relationship between the inner peripheral surface of the tube or the tire and the shock absorber 124 changes depending on whether the tire automatic air supply device 100 is located near the ground or away from the ground. As an example, with the tire automatic air supply device 100 located near the ground, the shock absorber 124 abuts or approaches the inner peripheral surface of the tube of the tire 16 or the radial outer portion of the tire, and the piston 104 is at bottom dead center. Designed or set to be located in. In this case, the piston 104 is held at bottom dead center even if the tire 16 rolls. Further, as another example, when the tire automatic air supply device 100 is away from the ground, the shock absorber 124 abuts or approaches the inner peripheral surface of the tube of the tire 16 or the radial outer portion of the tire, and the piston 104 is lowered. Designed or set to be at dead center. In this case, when the tire 16 rolls, the piston 104 reciprocates slightly near the bottom dead center. No air supply is performed until the piston 104 reaches the upper portion 132B of the inner peripheral surface 132 of the cylinder 108. The stroke amount of the piston 104 at which air supply is started can be adjusted by designing the distance between the upper portion 132B and the bottom wall portion 134.

Next, the operation of the tire automatic air supply device 100 will be described. As described above, under normal conditions, the shock absorber 124 abuts or approaches the inner peripheral surface of the radial outer portion of the tube (or tire) of the tire 16, and the piston 104 is held at bottom dead center. Alternatively, the piston 104 reciprocates slightly near bottom dead center. When the air in the tire 16 is less than normal, the shock absorber 124 is the diameter of the tube (or tire) of the tire 16 when the automatic tire air supply device 100 comes close to the ground as the tire 16 rolls. The piston 104 abuts on the inner peripheral surface of the outer portion in the direction, and the piston 104 is urged upward against the urging force of the elastic member 120 via the swing rod 122 and the piston shaft 102, and the inside of the cylinder 108 is above the normal state. Move to position. When the piston 104 is moving on the lower portion 132A of the inner peripheral surface 132 of the cylinder 108, the piston 104 slides on the lower portion 132A (there is almost no gap between the piston 104 and the lower portion 132A). Therefore, almost no air enters the intermediate space 110. Therefore, the intermediate space 110 has a negative pressure. When the piston 104 further rises and moves to the upper portion 132B, air flows from the outer side space 106 into the intermediate space 110 in the negative pressure state through the gap between the piston 104 and the upper portion 132B.

When the tire 16 rolls and the tire automatic air supply device 100 comes to a position away from the ground, the piston 104 is urged by the elastic member 120 and moves downward (outward in the radial direction). When the piston 104 moves to the lower portion 132A of the inner peripheral surface 132 of the cylinder 108, the air in the intermediate space 110 is compressed by the piston 104 to become a positive pressure, and the valve member 144 constituting the cylinder check valve 118 is expanded and passed through. Air flows from the intermediate space 110 to the tire side space 114 through the pores 140 and 142. As a result, air is supplied into the tire 16. When sufficient air is supplied to the tire 16, the piston 104 is held at bottom dead center even when the tire automatic air supply device 100 comes close to the ground. Alternatively, the piston 104 reciprocates a small amount near the bottom dead center (below the upper portion 132B). As a result, the air supply to the tire 16 by the tire automatic air supply device 100 is completed. In addition, the above-mentioned one cycle may return to the normal state, or the same cycle as above may be repeated a plurality of times to return to the normal state.

The tire automatic air supply device 100 is configured so that the outer space 106 above the piston 104 always communicates with the outside. Then, in the ascending process of the piston 104, the asymmetric vent 112 is formed from the external space 106 to the intermediate space by the differential pressure between the negative pressure of the intermediate space 110 below the piston 104 inside the cylinder 108 and the pressure of the external space 106. It is configured to allow air to flow into 110. Therefore, the pressure above the atmospheric pressure does not act on the piston 104 in the ascending process of the piston 104. Further, since the cylinder 108 is housed in the exterior body 116, the degree of freedom in designing the cylinder 108 is higher than that in the configuration in which the cylinder 108 is housed in the valve stem 14. Therefore, it is possible to adopt a cylinder 108 having a length that does not compress the elastic member 120 to the limit even with a long piston stroke and the piston 104 does not interfere with the upper member of the cylinder 108 (head 136 in the first embodiment). can. Therefore, the piston shaft 102 and the like are less likely to be damaged. Further, since the length of the cylinder 108 may be long enough to correspond to the moving region of the piston 104, a compact design necessary and sufficient in the longitudinal direction can be obtained.

Further, although the asymmetric ventilation portion 112 has a simple structure, it is in the middle of the lower side of the piston 104 through the gap between the upper portion 132B of the inner peripheral surface 132 of the cylinder 108 and the piston 104 in the ascending process of the piston 104. Air flows from the external space 106 into the intermediate space 110 with a small resistance due to the difference pressure between the negative pressure of the space 110 and the pressure (atmospheric pressure) of the external space 106 above the piston 104. Further, since the lower portion 132A of the inner peripheral surface 132 of the cylinder 108 and the piston 104 slide in the descending process of the piston 104, the intermediate space 110 below the piston 104 to the outer space above the piston 104. The flow of air to 106 can be restricted.

Further, since the ventilation hole 140 is formed near the lower end of the cylinder 108, most of the air in the intermediate space 110 below the piston 104 can be supplied into the tire 16. On the other hand, since the ventilation hole 142 is formed above the piston 104 at the bottom dead center, under normal conditions (the state where the piston 104 is located at the bottom dead center), it is above the piston 104 by a manual air pump or an electric compressor. Air can be supplied from the external space 106 to the tire side space 114 through the ventilation holes 142.

Next, a second embodiment of the present invention will be described. As shown in FIG. 4, in the tire automatic air supply device 200 according to the second embodiment, a piston check valve 270 is installed on the piston 204, and the piston check valve 270 constitutes an asymmetric ventilation portion. There is. Further, the diameter of the inner peripheral surface 232 of the cylinder 208 is constant. Since the other components are the same as or similar to the tire automatic air supply device 100 according to the first embodiment, the same components will be designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted. Further, the points different from the first embodiment will be briefly described by giving the member names common to the first embodiment for similar components, and the description of the points common to the first embodiment will be omitted as appropriate. ..

The piston shaft 202 is longer than the piston shaft 102 and the shock absorber 224 is directly attached to the lower end. The swinging rod 222 is also longer than the swinging rod 122 and is arranged coaxially with the piston shaft 202 with a gap between it and the piston shaft 202, and its lower end is in contact with the upper end of the shock absorber 224. The seal tube 228 is also longer than the seal tube 128 and accommodates the swing rod 222 in a slidable manner. It should be noted that a rubber tubular body such as the protective body 126 is not provided between the seal tube 228 and the rocking rod 222. A spring seat member 272 is fitted inside the upper end of the seal tube 228. The spring seat member 272 is composed of a tubular portion fitted to the seal tube 228 and a top plate portion, and a through hole is formed in the center of the top plate portion. The piston shaft 202 is inserted through the through hole of the top plate. A gap is provided between the through hole of the top plate and the piston shaft 202. The tire side space 114 communicates with the space inside the seal pipe 228 through this gap. Further, there is a gap through which air can be ventilated between the inner peripheral surface of the seal pipe 228 and the outer peripheral surface of the rocking rod 222, and air is supplied from the tire side space 114 into the valve stem 14 through this gap. It has become so. A groove (not shown) in the longitudinal direction (not shown) is formed on at least one of the inner peripheral surface of the seal pipe 228 and the outer peripheral surface of the rocking rod 222, and the valve stem 14 is formed from the tire side space 114 through the groove. Air may be supplied to the inside. A lower annular member 248 is fitted to the outside of the upper end of the seal tube 228. The lower annular member 248 is fitted inside the upper end of the mounting screw portion 146. The seal tube 228 is supported by the mounting screw portion 146 via the lower annular member 248.

The piston 204 is composed of a piston check valve 270 and an outer peripheral portion 204B. As shown in FIG. 5, the piston check valve 270 is composed of a valve body 274, a valve seat member 276, and a top plate portion 278. The valve body 274 is a disk or columnar member attached to the upper end of the piston shaft 202, and the lower surface is a tapered surface whose diameter is reduced downward. The valve seat member 276 is a cylindrical body, and the inner diameter of the lower half of the valve seat member 276 is constant and smaller than the outer diameter of the valve body 274. On the other hand, the inner diameter of the upper half of the valve seat member 276 is expanding upward. That is, the inner peripheral surface of the upper half of the valve seat member 276 is a conical surface whose diameter increases upward. The top plate portion 278 covers the upper end of the valve body 274. The valve body 274 is housed in a space surrounded by the upper half of the valve seat member 276 and the top plate portion 278. The valve body 274 can move a predetermined vertical interval in this space between the position where the valve body 274 abuts on the tapered surface of the valve seat member 276 and the position where the valve body 274 abuts on the top plate portion 278. It has become. A ventilation hole 280 that penetrates in the vertical direction is formed in a portion of the top plate portion 278 that does not come into contact with the valve body 274.

Unlike the cylinder 108, the cylinder 208 has a constant diameter of the inner peripheral surface 232 as described above. A bottom wall portion 234 similar to the bottom wall portion 134 is fitted to the lower end of the cylinder 208. A ventilation hole 240 similar to the ventilation hole 140 is formed at a position close to the bottom surface of the cylinder 208 (the upper surface of the bottom wall portion 234). On the other hand, the ventilation hole 242 is formed at a position above the ventilation hole 142. On the outer peripheral surface of the cylinder 208, valve members 244A and 244B, which individually cover the ventilation holes 240 and 242 with elastic annular strips, are fitted in a tightly bound state. The vent hole 240 and the valve member 244A constitute a cylinder check valve 218A. The ventilation holes 242 and the valve member 244B constitute a cylinder check valve 218B. That is, two cylinder check valves are provided.

The exterior body 216 is slightly shorter than the exterior body 116. On the other hand, the upper annular member 250 is a tubular body longer than the upper annular member 150. The upper end of the upper annular member 250 is in contact with the collar of the head 136, similarly to the upper end of the cylinder 208. On the other hand, the lower end of the upper annular member 250 is close to the upper end of the valve member 244B.

The elastic member 220 is mounted between the top plate portion of the spring seat member 272 and the shock absorber 224. In the second embodiment, the elastic member 220 indirectly urges the piston 204 downward via the shock absorber 224 and the piston shaft 202. In a normal state (a state in which sufficient air is contained in the tire 16), the piston 204 is urged by the elastic member 220 and held at the bottom dead center (position where it abuts on the bottom wall portion 234). Further, in the normal state, the shock absorber 224 is held at a position isolated from the inner peripheral surface of the radial outer portion of the tube (or tire) of the tire 16 in the radial direction for a predetermined time.

Next, the operation of the tire automatic air supply device 200 will be described. As described above, under normal conditions, the shock absorber 224 abuts or approaches the inner peripheral surface of the radial outer portion of the tube (or tire) of the tire 16, and the piston 204 is held at bottom dead center. Alternatively, the piston 204 reciprocates slightly near bottom dead center. When the air in the tire 16 is less than normal, the shock absorber 224 is the diameter of the tube (or tire) of the tire 16 when the automatic tire air supply device 200 comes close to the ground as the tire 16 rolls. It abuts on the inner peripheral surface of the portion outside the direction and is urged upward against the urging force of the elastic member 220, and the piston 204 moves to a position above the normal state together with the shock absorber 224 and the piston shaft 202. In the ascending process of the piston 204, the valve body 274 of the piston check valve 270 abuts on the top plate portion 278, and a gap is formed between the valve body 274 and the tapered surface of the valve seat member 276. As a result, air flows from the outer space 106 to the intermediate space 110 through the ventilation holes 280 of the top plate and the gap between the valve body 274 and the tapered surface of the valve seat member 276.

When the tire 16 rolls and the tire automatic air supply device 200 comes to a position away from the ground, the shock absorber 224 is urged by the elastic member 220 and moves downward (outward in the radial direction), and the piston 204 also moves downward. .. In the descending process of the piston 204, the valve body 274 abuts on the tapered surface of the valve seat member 276, and no gap is formed between the valve body 274 and the valve seat member 276. Therefore, the air in the intermediate space 110 is compressed by the piston 204 to become a positive pressure, and the valve members 244A and 244B constituting the cylinder check valves 218A and 218B are expanded to expand the tires from the intermediate space 110 through the ventilation holes 240 and 242. Air flows into the side space 114. As a result, air is supplied into the tire 16. When sufficient air is supplied to the tire 16, the piston 204 is held at the bottom dead center even when the tire automatic air supply device 200 comes to a position close to the ground. Alternatively, the piston 204 reciprocates slightly near bottom dead center. As a result, the air supply to the tire 16 by the tire automatic air supply device 200 is completed. In the second embodiment, a slight amount of air is supplied even when the piston 204 reciprocates slightly in the vicinity of the bottom dead center.

In the second embodiment, the piston check valve 270 has a valve body 274 on which a tapered surface is formed and a valve seat member 276 on which a tapered surface is formed. If air flows from the external space to the intermediate space and the air flow from the intermediate space to the external space is restricted during the descending process of the piston and the air in the intermediate space is compressed, the configuration of the piston check valve is not particularly limited. .. For example, the valve body may be spherical. Further, the piston shaft may be attached to the valve seat member, and the spherical valve body may be urged by the elastic member toward the top plate portion of the valve seat member. In this case, a vent hole having a tapered surface whose diameter is reduced upward may be formed in the top plate portion, and the spherical valve body may be configured to abut / separate from the tapered surface of the vent hole. Further, a piston check valve and a piston as in the other structural example shown in FIG. 6 may be used. The piston 304 includes a metal bottomed cylindrical body 304A, a rubber outer peripheral portion 304B, and a piston check valve 370. The body 304A is coupled to the upper end of the piston shaft 202 at the bottom wall. Further, a through hole 372 is formed in the side wall of the main body 304A, and an elastic annular or tubular valve member 374 is fitted around the through hole 372 in a tightly bound state. These through holes 372 and the valve member 374 form the piston check valve 370. Further, the piston check valve may be a reed valve.

Further, in the first and second embodiments, two ventilation holes 140 and 142 are formed in the cylinder 108, and two ventilation holes 240 and 242 are formed in the cylinder 208, but the positions are separated in the longitudinal direction of the cylinder. 3 or more ventilation holes may be formed in the cylinder. Further, only one ventilation hole may be formed in the cylinder. Further, the cylinder check valve may be a reed valve in which a through hole is formed in the bottom wall portion 134 and 224, and the through hole is opened and closed by a reed.

Further, in the first embodiment, the piston shaft 102 and the swing rod 122 are housed in the protective body 126, but there is a problem that the tire tube or the tire is damaged due to bending or breakage of the piston shaft 102 and / or the swing rod 122. If this is not the case, a configuration without a protective body may be used. Further, in the first embodiment, the swing rod 122 is a cylindrical body, but the swing rod may be configured like a coil spring in close contact with the swing rod. Further, in the first embodiment, the piston shaft 102 may be coupled to the shock absorber 124 via the swing rod 122, but may have a structure in which the swing rod is not provided and the piston shaft is directly coupled to the shock absorber.

Further, although an example is shown in which the tire automatic air supply devices 100 and 200 are applied to a bicycle in the first and second embodiments, the tire automatic air supply according to the first and second embodiments and the present invention is shown. The device can also be applied to wheelchairs, motorcycles and the like.

INDUSTRIAL APPLICABILITY The present invention can be used for an automatic tire air supply device for automatically supplying air into tires of bicycles, wheelchairs, motorcycles and the like.

10 Bicycle 12 Wheel 14 Valve stem 16 Tire 18 Rim 100, 200 Tire automatic air supply device 102, 202 Piston shaft 104, 204, 304 Piston 106 External side space 108, 208 Cylinder 110 Intermediate space 112 Asymmetric vent 114 Tire side space 116 216 Exterior body 118, 218A, 218B Cylinder check valve 120, 220 Elastic member 122, 222 Swing rod 124, 224 Buffer body 126 Protective body 128, 228 Seal tube 130 Seal 132, 232 Inner peripheral surface 132A Lower part 132B Upper part 140, 142, 240, 242 Vent holes 144, 244A, 244B Valve member 270, 370 Piston check valve (asymmetric vent)

Claims (5)

A piston shaft that is inserted into the valve stem with a rod-shaped body and is configured to be pushed upward when the tire rolls and the valve stem approaches the ground.
With the piston attached to the piston shaft,
A cylinder configured to slidably accommodate the piston in a cylindrical body so that the outer space above the piston always communicates with the outside.
In the ascending process of the piston, air flows from the external space into the intermediate space due to the differential pressure between the negative pressure in the intermediate space below the piston and the pressure in the external space of the cylinder, and the piston An asymmetric vent that is configured to limit the flow of air from the intermediate space to the external space during the descent process.
An exterior body that accommodates the cylinder and forms a tire-side space that communicates with the outer peripheral surface of the cylinder and communicates with the inside of the tire.
A cylinder check valve that allows air flow from the intermediate space to the tire side space and blocks the opposite air flow.
An elastic member that urges the piston downward, and
Tire automatic air supply device equipped with. In claim 1,
The inner peripheral surface of the cylinder is composed of a lower portion on which the piston slides and an upper portion having a diameter larger than that of the lower portion and forming a gap between the piston and the inner peripheral surface of the cylinder. A tire automatic air supply device in which the piston and the piston form the asymmetric ventilation portion. In claim 1,
The asymmetric ventilation unit is a tire automatic air supply device which is a piston check valve installed on the piston. In claim 1 ,
A ventilation hole penetrating from the inner peripheral surface to the outer peripheral surface is formed in the cylinder, and a valve member covering the ventilation hole with an elastic tubular body is fitted to the outer peripheral surface of the cylinder in a tightly bound state. A tire automatic air supply device in which a ventilation hole and the valve member constitute the cylinder check valve. In claim 4,
A tire automatic air supply device in which a plurality of ventilation holes are formed at positions apart from each other in the longitudinal direction of the cylinder.

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