JPH11351992A - Air pressure measuring apparatus for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an air pressure measuring apparatus for tire in which leakage of air pressure is prevented even when a tire valve has a trouble. SOLUTION: A first resilient member 32 for forming a first hermetically sealed chamber 29 isolated from the outer air between a tire valve and a body 12 under a state where the tire valve is fixed to the body 12 is disposed on the outer circumference at the forward end part of a push rod 15G. A second resilient member 17 for changing a space 31, having same pressure as the outer air before the spindle shaft of the tire valve is pressed by the push rod 15G, into a second hermetically sealed chamber 30 isolated from the outer air when the spindle shaft of the tire valve is pressed by the push rod 15G is disposed on the outer circumference of a cylinder member 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire pressure measuring device which is mounted on a tire valve and measures tire pressure.

[0002]

2. Description of the Related Art As a conventional tire pressure measuring device, for example, at the time of measurement, by pressing against a valve of a tire, a projection projecting from the center of the measuring device presses a spindle of the valve, and the internal air pressure is measured. There is a thing which leads to a measuring instrument. In this air pressure measuring device, in order to prevent the air from leaking, it is necessary to completely seal the air pressure of the tire by contacting the air of the air pressure measuring device and the sealing gasket with the base of the valve stem.

[0003] The present applicant also discloses another tire pressure measuring device, for example, a movable upper cover, a lower cover provided on the outer periphery of the upper cover, and a tire which is integrally moved with the upper cover in the axial direction. An opening / closing member that opens the valve of the tube and introduces air pressure to close the valve when not moving, a moving member that is housed in the opening / closing member and that moves by air pressure introduced from the opening / closing member, and biases the moving member A spring whose displacement changes according to the magnitude of the pressure,
There has been proposed a tire valve cap including a display portion provided on the outer periphery of an opening / closing member and displaying a moving amount of a moving member (Japanese Patent Application Laid-Open Nos. 8-4941, 8-326955,
JP-A-8-327481, JP-A-9-112720
No., see).

[0004]

However, in such a conventional tire pressure measuring instrument, dust that directly enters the tire valve can be prevented, but the valve is surely leaked due to some reason. When the situation cannot be prevented, air leakage from the tire cannot be prevented. The failure of the tire valve occurs when the packing of the valve is deteriorated, when the packing and the valve seat are misaligned, or when dust is clogged between the packing and the valve seat.

[0005] In many cases, these air leaks are not leaking in a loud noise with a shoe shoe, but are leaked in very small amounts. Disappears, and it becomes impossible to drive as it is. The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a tire pressure measuring instrument capable of preventing air leakage due to a failure of a tire valve.

[0006]

In order to achieve this object, the present invention is configured as follows (see FIG. 1). The present invention relates to a body detachably attached to a base of a tire valve, a lower cover fixed to the body, an upper cover movably provided on an inner periphery of the lower cover, the upper cover and the body. A spring installed with an initial load between the spring and a push rod that pushes the spindle shaft of the tire valve by moving in the axial direction integrally with the upper cover to open the tire valve and introduce air pressure. An integrally provided cylinder member, a piston member housed in the cylinder member and moved by air pressure introduced from the cylinder member, and an initial load applied to the piston member to urge the piston member to change its displacement according to the magnitude of the air pressure A tire pressure measuring instrument having a spring and a display portion provided on the outer periphery of the cylinder member for displaying the movement amount of the piston member. A first elastic member that forms a first sealed chamber between the tire valve and the body that is isolated from outside air when the body is mounted on the tire valve; And a second elastic member that serves as a second sealed chamber in which a space having the same pressure as the outside air before being pressed when the spindle shaft of the tire valve is pressed by the push rod is closed as a second sealed chamber. Provided on the outer periphery of the tip of the member.

The first elastic member of the present invention comprises an O-ring inserted into a groove formed on the outer periphery of the distal end of the push rod, and the second elastic member is provided on the outer periphery of the distal end of the cylinder member. It consists of an O-ring inserted into the formed groove. Further, the first sealed chamber of the present invention is formed in a small-diameter first seal cylinder portion communicating with a guide hole of the body inserted into the tire valve, and the second sealed chamber is formed of the first sealed cylinder. The second formed larger in diameter than the seal cylinder
Is formed in the seal cylinder portion.

Further, when the spindle shaft of the tire valve is pressed, the distal end surface of the sleeve incorporated in the push rod comes into contact with the distal end surface of the first seal cylinder portion of the present invention, and the second seal cylinder portion Abuts against the stopper surface of the cylinder member. According to the present invention having such a configuration, the first elastic member is provided on the outer periphery of the distal end portion of the push rod in a state where the body is mounted on the tire valve, and the outside air is blocked between the tire valve and the body. When the measurement is not performed because the first sealed chamber is formed, even if a malfunction occurs in the tire valve such as dust clogging, leakage of the tire air pressure can be prevented beforehand.

The first elastic member is constituted by an O-ring inserted into a groove formed on the outer periphery of the distal end of the push rod,
Since the second elastic member is constituted by the O-ring inserted into the groove formed on the outer periphery of the distal end portion of the cylinder member, the structure is simple. Further, the first sealed chamber is formed in the first seal cylinder portion so as to communicate with the guide hole of the body inserted into the tire valve, and the second sealed chamber is formed to have a larger diameter than the first seal cylinder portion. Since it is formed in the second seal cylinder portion, a sealed space can be obtained by slightly changing the structure of the body.

Further, when the spindle shaft of the valve is pressed, the distal end surface of the first seal cylinder portion comes into contact with the distal end surface of the sleeve incorporated in the push rod, and the distal end surface of the second seal cylinder portion comes into contact with the cylinder member. The second sealing chamber can be easily formed, the second sealing chamber can be filled with air pressure, the piston can be pushed up, and the measurement of the air pressure can be easily performed.

[0011]

FIG. 1 is a sectional view of a tire pressure measuring instrument according to an embodiment of the present invention. The upper half of FIG. 1 shows a state at the time of non-measurement without pressing the upper cover 14, and the lower half shows a state at the time of tire pressure measurement with the upper cover 14 pressed in to check the tire pressure. Further, FIG. 1 shows one state of the piston 23 in an initial state in which measurement is started, and two states in which the cylinder 15 is filled with air.

In FIG. 1, reference numeral 12 denotes a body, and a guide hole 12G is formed in the body 12, and the guide hole 12G is formed.
Is inserted into the tire base. The guide hole 12G has a function of guiding to the valve base, and is formed with a screw portion 12H for fixing to the valve base. A packing 28 made of a flexible material such as rubber is provided at the bottom of the guide hole 12G.
Are bonded, and a through hole 28A is formed in the packing 28.

The body 12 has a through hole 28 formed in the packing 28.
A small-diameter cylindrical first seal cylinder portion 1 communicating with A
2F is formed. When the measurement of tire pressure is to be started by inserting the valve base into the guide hole 12G, the push rod 15G integrally formed at the tip of the cylinder member 15 projects from the first seal cylinder portion 12F and the through hole 28A. However, when a pressing force is applied to measure, the push rod 15G projects through the first seal cylinder portion 12F and the through hole 28A to push the spindle of the tire valve to open the valve.

First seal cylinder portion 12 of body 12
A large-diameter cylindrical second seal cylinder portion 1 is provided outside F.
2C is formed, and a retainer groove 12B for receiving the spring 16 is formed on the outer peripheral end surface thereof. A fitting groove 12D for fitting and fixing the lower cover 11 is provided on an outer peripheral portion of the body 12, and a guide rib 12 guided by a guide groove 11D formed inside the lower cover 11 subsequently thereto.
A is formed. The lower cover 11 is attached and fixed to the body 12.

The lower cover 11 is a cylindrical member opened on both sides, and has a fitting projection 11A formed on the left inner end fixed to the body 12 side. A guide groove 11D that fits into the guide rib 12A of the body 12 is formed. For the lower cover 11 fitted and fixed to the body 12, the upper cover 14
Are movably incorporated in the direction of the body 12. The upper cover 14 is formed of a transparent plastic material so that the internal structure can be seen from the outside.

A cylinder member 15 is housed in the upper cover 14 movably incorporated on the body 12 side with respect to the lower cover 11 with a disk 27 housed at the right end. Are press-fitted and integrated so as to be slidable integrally in the axial direction.
In the state of being pressed against the right side of the upper cover 14 under the pressure of the assembly.

A push rod 15G is formed at the tip of the cylinder member 15 on the body 12 side, and a seal piston 15C is formed following the push rod 15G.
A groove 15I for mounting an O-ring 17 (second elastic member) is formed around the seal piston 15C. A cylindrical cylinder chamber 15D is formed following the seal piston 15C, and a slide cylindrical section 15H that is in circumferential contact with the upper cover 14 located outside is formed on the outer peripheral portion of the cylinder chamber 15D. At a plurality of locations on the outer periphery of the slide cylindrical portion 15H, ventilation grooves 15M are formed in the axial direction.

A guide portion 15 is provided at the rear of the cylinder chamber 15D.
E is integrally formed, and slits are formed at two positions facing the guide portion 15E in the radial direction. Cylinder member 1
The push rod 15G formed at the tip of the fifth 5 is provided with a vent hole 15J and protrudes from the seal piston 15C, so that the tire air pressure can be introduced into the internal cylinder chamber 15D by the vent hole 15J.

A scale display section 15F is formed along a slit formed in a rear guide section 15E following the cylinder chamber 15D. The cylinder member 15 press-fitted into the upper cover 14 receives a holding spring 16 incorporated between the upper cover 14 and the body 12 with a spring receiver 15 </ b> A. It is fitted to the receiver 27B.

The push rod 1 of the cylinder member 15
Groove 15I of seal piston 15C formed outside 5G
, An O-ring 17 is mounted. When the cylinder member 15 pushes the upper cover 14 to the left, the cylinder member 15 moves against the holding spring 16, and the push rod 15G
Is pushed from the first seal cylinder portion 12F of the body 12 and the through hole 28A of the packing 28.

Before the upper cover 14 is pressed, the push rod 1 is moved by the holding spring 16 provided with an initial load between the upper cover 14 and the body 12.
5G is a predetermined distance from the head of the spindle of the tire valve, here to the surface of the packing 28. At the same time, the seal piston 15C is fitted into the second seal cylinder portion 12C of the body 12 by a seal using an O-ring 17, and a seal for introducing air pressure of the tire from the first seal cylinder portion 12F of the body 12 to the cylinder chamber 15D. (See arrow A).

A piston 23 having an O-ring 24 mounted therein is slidably incorporated in a cylinder chamber 15D of the cylinder member 15. A return spring 26 is incorporated between the piston 23 and the disk 27 located behind. The disc 27 is formed integrally with a guide portion 27A into which the right side of the return spring 26 is fitted.
The buckling deformation of No. 6 is suppressed. At the right end of the piston 23, a pressure indicator 23 flared in the radial direction is provided.
C is formed integrally.

The pressure indicating section 23C is a cylinder member 1
5 is located in the two slits on the rear side, and indicates the indicated pressure value to the scale display section 15F. The pressure indicating section 23C is desirably colored red or yellow for easy viewing from the outside. A sleeve 22 is incorporated on the left air introduction side of the piston 23 housed in the cylinder member 15. The sleeve 22 has two portions 22B extending from a sleeve main body 22A having a vent 22E, and has a contact surface 22C at the tip of the two portions 22B.

The sleeve 22 is formed by fitting one part 22B into the vent hole 15J of the cylinder member 15.
It is incorporated in the part of the push rod 15G. The sleeve 22 moves together with the cylinder member 15 when the upper cover 14 is pushed to the left, before the stopper surface 15B of the cylinder member 15 comes into contact with the distal end surface 12K of the second seal cylinder portion 12C of the body 12 and stops. Then, the contact surface 22C of the sleeve 22 abuts on the distal end surface 12J of the second seal cylinder portion 12F of the body 12, and slightly moves the piston 23 rightward.

Due to the movement of the piston 23 due to the contact with the distal end face 12J of the sleeve 22, the O-ring 24 mounted on the piston 23 is not used for a long time, so that the O-ring 24 The attached state can be released, and the movement of the piston 23 by the subsequently introduced tire air pressure is reliably performed.

In order to move the piston 23 by contacting the distal end surface 12J of the sleeve 22, the cylinder member 15
The distance between the stopper surface 15B of the second seal cylinder portion 12C of the body 12 and the distal end surface 12K of the
The distance from the second contact surface 22C to the tip end surface 12J of the first seal cylinder portion 12F is shortened by the amount of forced movement of the piston 23.

In the initial state where the tire pressure is not introduced, the return spring 2 on the right side of the piston 23
6 is communicated with the cover chamber of the lower cover 11 by the slit of the cylinder member 15 and the ventilation groove 15M on the outer periphery. The cover room of the lower cover 11
The ventilation groove 14F of the upper cover 14 and the ventilation groove 11F provided in the right opening of the lower cover 11 communicate with the outside.

As a result, the outside and the chamber 20 incorporating the return pulling 26 on the right side of the piston 23 communicate with each other and are opened to the atmosphere. When the tire pressure is introduced to the left side of the piston 23, the piston 23 strokes rightward. At that time,
The stroke position is determined only by the force of the return spring 26. Here, a groove 15K is formed on the outer periphery of the distal end portion of the push rod 15G, and an O-ring 32 as a first elastic member is mounted in the groove 15K. In a state where the tire pressure is not measured without pushing in the upper cover 14, the O-ring 32 abuts on the inner periphery of the first seal cylinder portion 12F of the body 12, and the through-hole 28A of the packing 28 between the O-ring 32 and the base of the valve. First seal cylinder part 1
A first sealed chamber 29 that is isolated from the outside air by 2F is formed. Therefore, even when dust or the like gets into the tire valve and loses the function of completely sealing the air, it is possible to prevent air pressure from leaking.

The first seal cylinder portion 12F is formed in a small-diameter cylindrical shape, and the second seal cylinder portion 12C is formed in a cylinder having a larger diameter than the first seal cylinder portion 12F. In order to measure the air pressure, when the upper cover 14 is pushed in, the tip of the push rod 15G enters the through hole 28A of the packing 28, and as shown by the arrow A, the air inside the tire passes through the packing 28. Hole 2
8A, the second sealing chamber 30 is filled with air through the inside of the first sealing cylinder portion 12F, and the piston 23 is pushed up against the return spring 26 to a position balanced with the tire air pressure. A groove 15I is formed on the outer periphery of the seal piston 15C formed integrally with the cylinder member 15,
An O-ring 17 as a second elastic member is mounted in the groove 15I. With the upper cover 14 pushed in,
The O-ring 17 is in contact with the inner periphery of the second seal cylinder portion 12F, and the second seal chamber 30 is formed by the second seal cylinder portion 12F, the seal piston 12C, and the sleeve 22. That is, the distal end surface 12J of the first seal cylinder portion 12F contacts the contact surface 22C of the sleeve 22,
When the distal end surface 12K of the second seal cylinder portion 12C abuts against the stopper surface 15B of the seal piston 15C, the space 31 having the same pressure as the outside air is converted into the second sealing hole 30 completely blocked from the outside air. . Therefore, even when the upper cover 14 is pushed in for measuring the air pressure, it is possible to prevent the air pressure of the tire valve from leaking.

FIG. 2 is a left side view of FIG. In FIG. 2, reference numeral 12 denotes a body, and a cylindrical lower cover 11 is fixed to an outer periphery of the body 12. A guide hole 12G is formed in the body 12, and a tire cap is inserted into the guide hole 12G and screwed. A screw portion 12H is formed in the guide hole 12G, and the tire air pressure measuring device 10 is screwed and fixed to a tire base. A packing 28 formed of a flexible material such as rubber is adhered to the guide hole 12G, and a through hole 28A is formed in the packing 28.
Are formed.

In a state before the upper cover 14 is pushed in, the push rod 15G formed integrally with the tip of the cylinder member 15 is provided with the first seal cylinder portion 12F formed on the body 12 and the through-hole formed on the packing 28. Although it does not protrude from the hole 28A toward the tire base,
When the upper cover 14 is pushed in, the push rod 15G projects from the first seal cylinder portion 12F and the through hole 28A and pushes the spindle of the tire valve to open the valve.

Next, referring to FIG. 1, the operation of measuring the tire pressure by pushing the upper cover 14 to the left will be described. As shown in the upper half of FIG. 1, in a state where the upper cover 14 is not pushed leftward, the guide hole 12G of the body 12 is inserted into the tire base and screwed.
The tire pressure measuring device 10 is inserted into the tire base and is screwed, the outer periphery of the tire base is in contact with the packing 28 provided in the guide hole 12G, and the push rod 15G is connected to the first seal cylinder. Part 12F,
It is not inserted into the through hole 28A.

In this state, the O-ring 32 is in contact with the inner periphery of the first seal cylinder portion 12F, and the through-hole 28A of the packing 28 and the first seal cylinder portion First sealed chamber 2 by 12F
9 is formed. Therefore, even if a failure occurs in the tire valve due to dust clogging or the like, leakage of air pressure can be prevented.

In this state, when the upper cover 14 is pushed in with a finger, the internal cylinder member 15 moves at the same time as the upper cover 14 moves to the left. Cylinder member 15
Is moved, first, the sleeve 22 incorporated in the tip
Abuts against the distal end surface 12J of the first seal cylinder portion 12F of the body 12. For this reason, sleeve 2
2 is stopped, and when the cylinder member 15 is further pushed in, the movement of the piston 23 via the sleeve 22 is stopped.
Moves to the left. At this time, the O-ring 24 is
Even if it is stuck to the inner peripheral surface of D, it is separated by the relative movement of the piston 23 and the cylinder member 15, and the movement of the piston 23 by the subsequent introduction of air pressure is facilitated.

When the cylinder member 15 is further moved to the left by the upper cover 14, the stopper surface 15B of the cylinder member 15 is moved to the second seal cylinder portion 12C of the body 12.
Abuts against the distal end surface 12K of the In this state, the cylinder member 1
The push rod 15G provided at the tip of the body 5 is the body 1
2 first seal cylinder portion 12F and packing 28
Projecting to the position shown by the lower half through the through hole 28A of
Also, a seal piston 15 on the tip end side of the cylinder member 15
C is inserted into the second seal cylinder portion 12C of the body 12, and the space 31 extending from the second seal cylinder portion 12C of the body 12 to the cylinder chamber on the left side of the piston 23 by the O-ring 17 is formed in the second seal chamber 30. And For this reason,
No air pressure leaks when measuring air pressure.

The push rod 15G is connected to the first
Of the seal cylinder portion 12F and the through hole 28A of the packing 28, the spindle protrudes at this position in an assembled state with respect to the tire base, the push rod 15G pushes the spindle, and the valve is opened.
As indicated by an arrow A, the tire pressure passes through the through hole 28A of the packing 28, the first seal cylinder portion 12F, and
And is introduced into the tire pressure measuring device 10.

As a result, the tire air pressure is received by the left chamber 18 of the piston 23 and moves to the right against the return spring 26 by the air pressure introduced by the piston 23.
The piston 23 stops at a position where the force of the tire pressure in the left chamber 18 and the force of the right return spring 26 are balanced. In the stopped state of the piston 23, the pressure indicating portion 23C formed in an ear shape at the right end of the piston 23 stops at an appropriate position on the scale display portion 15F, and displays the pressure value of the introduced tire air pressure. .

Therefore, when checking the tire pressure,
The state of the tire pressure can be immediately known just by looking at the display of the tire pressure measuring device 10. When the measurement of the tire air pressure is completed and the upper cover 14 is released, the holding member 16 returns the cylinder member 15 and the upper cover 14 to the initial state. The O-ring 32 moves into the first seal cylinder portion 12F integrally with the push rod 15G, and forms the first sealed chamber 29 again.

In this first sealed chamber 29, if the tire valve is normal, the O-ring 32 is unnecessary and the atmosphere becomes atmospheric.
When the tire valve becomes defective for some reason, the first sealed chamber 29 is formed, and it is possible to prevent the air pressure of the tire from becoming atmospheric. As mentioned above, it was explained in a state where it was attached to the valve attached to the tire,
Needless to say, it can be used in any pressure vessel other than tires.

[0040]

As described above, according to the present invention, when the body is mounted on the tire valve, the first sealed chamber which forms a first sealed chamber between the tire valve and the body, which is shut off from the outside air, is formed. A second sealed chamber, wherein the first elastic member is provided on the outer periphery of the distal end portion of the push rod, and when the spindle shaft of the tire valve is pressed by the push rod, a space having the same pressure as the outside air before being pushed is shut off from the outside air; Since the second elastic member is provided on the outer periphery of the distal end portion of the cylinder member, leakage of air pressure can be prevented beforehand even in the case where a failure occurs in the valve of the tire, such as when dust is clogged.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a side view of FIG. 1;

[Explanation of symbols]

 10: Tire pressure measuring device 11: Lower cover 11A: Fitting protrusion 11D: Guide groove 11F: Vent groove 12: Body 12A: Guide rib 12B: Retainer groove 12C: Second seal cylinder portion 12D: Fitting groove 12F: First 12G: Guide hole 12H: Screw portion 12J, 12K: Tip surface 14: Upper cover 14F: Ventilation groove 15: Cylinder member 15A: Spring receiver 15B: Stopper surface 15C: Seal piston 15D: Cylinder chamber 15E: Guide portion 15F: Scale display part 15G: Push rod 15H: Slide cylindrical part 15I, 15K: Groove 15J: Vent hole 15M: Vent groove 16: Holding spring 17: O-ring (second elastic member) 18, 20: Chamber 22: Sleeve 22A: Sleeve body 22B: One part 22C: Contact surface 2 E: vent hole 23: piston (piston member) 23C: pressure indicating part 24: O-ring 26: return spring 27: disk 27A: guide part 28B: cylinder receiver 28: packing 28A: through hole 29: first sealed chamber 30 : Second sealed chamber 31: Space 32: O-ring (first elastic member)

Claims (4)

[Claims] 1. A body detachably mounted on a base of a tire valve, a lower cover fixed to the body, an upper cover movably provided on an inner periphery of the lower cover, A spring installed with an initial load between itself and a body, and a push rod that presses a spindle shaft of the tire valve by moving in an axial direction integrally with the upper cover to open the tire valve and introduce air pressure. A piston member housed in the cylinder member, the piston member being moved by air pressure introduced from the cylinder member, and a bias applied to the piston member with an initial load, and the displacement of the piston member is increased by the magnitude of the air pressure. Tire pressure measurement having a changing spring, and a display unit provided on an outer periphery of the cylinder member for displaying a movement amount of the piston member. A first elastic member that forms a first sealed chamber between the tire valve and the body and that is isolated from outside air when the body is mounted on the tire valve; A second elastic member which is provided on the outer periphery and serves as a second sealed chamber in which a space having the same pressure as the outside air before being pressed when the spindle shaft of the tire valve is pressed by the push rod is shut off from the outside air; A tire pressure measuring device provided on an outer periphery of a tip portion of a cylinder member. 2. The tire air pressure measuring device according to claim 1, wherein the first elastic member comprises an O-ring inserted into a groove formed on an outer periphery of a distal end portion of the push rod, and the second elastic member comprises a second elastic member. The tire pressure measuring device is characterized in that the member comprises an O-ring inserted into a groove formed on the outer periphery of the tip of the cylinder member. 3. The tire air pressure measuring device according to claim 1, wherein the first sealing chamber communicates with a guide hole of the body inserted into the tire valve and is formed in a first sealing cylinder portion. The tire pressure measuring device according to claim 1, wherein the second sealing chamber is formed in a second sealing cylinder portion having a larger diameter than the first sealing cylinder portion. 4. The tire air pressure measuring device according to claim 3, wherein a tip end surface of the sleeve incorporated in the push rod when the spindle shaft of the tire valve is pressed is applied to a tip end surface of the first seal cylinder portion. The tire pressure measuring device is in contact with a tip surface of the second seal cylinder portion and a stopper surface of the cylinder member.