JPH11139118A - Tire pressure adjusting device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A pump that converts the rotational force of a wheel into a linear motion and pressurizes air to the tire without using a centrifugal force and without preparing a special tire or rim. Attach to SOLUTION: A pump unit 20 reciprocating in the same direction as the axle 10 is disposed on a member such as a flange 11 which rotates together with an axle 10 of a vehicle, and one end of a piston of the pump unit 20 is provided on a cam member 40. By contacting a slope 42 that generates a stroke in a direction substantially perpendicular to the axle 10, the rotational movement of the rotating member is converted into a reciprocating movement, and the external air sucked from the suction hole of the pump unit 20 is compressed. The air is supplied to the tire 6 of the vehicle via the safety valve 60 set at an arbitrary air pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air pressure adjusting device for maintaining the air pressure of a tire at an arbitrary preset value by utilizing the rotation of an axle of a vehicle.

[0002]

2. Description of the Related Art As a conventional technique for automatically adjusting the tire air pressure by using the rotation of a vehicle wheel, a piston of an air pump attached to a rim of a wheel uses a centrifugal force caused by the rotation of the wheel on the rim. It is well known to be driven in a radial direction and to inhale outside air to replenish the tire pressure. However, this technique has the disadvantage that the pump must be permanently attached to the rim, special tires and rims are required, and the tires must be removed when checking or replacing the pump. there were.

On the other hand, a technology in which an air pump driven by a combined force of a gravity vector and a centrifugal force vector is arranged at a position eccentric from the center of rotation of a wheel in front of a tire wheel is disclosed in Japanese Patent Application Laid-Open No. Hei 6-510252. Has been proposed.
FIGS. 6 and 7 show an outline of this technique, in which a pump device is disposed at a position 114 away from the rotation axis 118 of the tire by R, and the tire rotates 0 °, 60 °, 180 °.
FIG. 7 shows the magnitude and direction of the combined force of the gravity vector 112 and the centrifugal force vector 110 for each rotation. FIG. 7 shows a conceptual diagram of the pump device 130.

According to FIG. 6, the combined force of a gravitational vector 112 and a centrifugal force vector 110 as a driving force of an air pump changes to R1, R2, and R3 in accordance with the rotation angle of the tire. That is, at 0 ° rotation, R1 becomes downward and 1
At 80 ° rotation, R3 is directed upward.

The pump device 130 shown in FIG. 7 is driven by the combined force. The first piston 131 in the first cylinder 132 is connected to the second cylinder 148 via the lot 144.
And a second piston 147 having a sufficiently large mass as compared with the first piston 131. Tire 14
When 1 is rotated by 0 °, the resultant force R1 of the gravitational vector 112 of the second piston 147 and the centrifugal force vector 110 acts downward, so that the second cylinder 14
8, the 147B side is at the atmospheric pressure, while the 147A side is maintained at the compressed air pressure controlled by the pilot valve 151. On the other hand, as the volume on the 131A side of the first cylinder 132 also decreases, air at a set pressure flows from the air pipe 134 through the
It is pumped into 1. Air exceeding the set pressure is discharged from the regulator 140. Then, the first cylinder 132
The outside air sucked from the duct 136 when the volume expands is supplied to the 131B side via the pilot valve 135.

When the tire reaches 180 ° rotation, the gravity vector 112 of the second piston 147 and the centrifugal force vector 11
Although the resultant force R3 of 0 acts on the road surface upward, it is much smaller than that of R1.
The volume of the first cylinder 132 on the 131B side is reduced by the force of the compressed air stored on the 7A side, and the air at the set pressure passes from the air pipe 133 through the air pipe 137 via the pilot valve 135 into the tire 141. Pumped. Outside air sucked from the duct 136 when the volume expands is supplied to the 131A side of the first cylinder 132 via the pilot valve 135.

[0007]

However, FIG. 6 and FIG.
Although the technology shown in Fig. 1 makes it possible to provide rear-mounted devices that do not require special tires and rims, the centrifugal force vector decreases when the vehicle runs at low speed, and a predetermined piston driving force is obtained. However, there is a problem that the wheel balance at the time of high-speed running is lost because the position of the pump device is eccentric by R from the rotation axis of the tire. In view of the above, the present invention provides a mechanism for driving a pump by converting the rotational force of a wheel into a linear motion without using a centrifugal force, thereby solving the problems of the prior art.

[0008]

A pump unit that reciprocates in the same direction as the axle is disposed on a member such as a flange or a brake drum of the axle that rotates together with the axle of the vehicle. The rotation of the wheels is brought into contact with the slope of the non-rotating cam member to convert the piston of the pump unit into a reciprocating motion corresponding to the rotational motion of the rotating member. Compress and supply air to the vehicle tires via the safety valve.

If the cam member is provided outside the tire wheel and has a balance weight suspended from the axle via a bearing, a pump unit which can be easily maintained can be provided. In addition, if a cover that covers the entire cam member is attached, dust and water around the cam member can be easily protected.

As another form, if the cam member is disposed inside the tire wheel and is fixed to the non-rotating portion on the axle housing side, the dust / waterproof cover can be omitted.

Further, if a safety valve arranged between the pump unit and the air pipe connecting the tire is provided with an adjusting mechanism for arbitrarily increasing or decreasing the tire air pressure, the tire air pressure is reduced on a snowy road to increase the contact area. It is also possible to improve the road surface adhesion.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. Figures 1-3
Shows an example in which a tire pressure adjusting device is provided outside the tire wheel 4.

In FIG. 1, a tire wheel 4 is mounted on an outer periphery of an axle housing 1, which is a non-rotating member, where the hub 3 is supported by a pair of tapered roller bearings 2 opposed to each other. A rim 5 is provided on the outer periphery of the tire wheel 4 and a known tire 6 is mounted. A brake drum 7 is also mounted on the hub 3, and generates a braking force between the hub 3 and a brake shoe 9 supported by a back plate 8 attached to the axle housing 1. On the other hand, an axle 10 for transmitting a driving force is arranged in the axle housing 1 and fixed to the hub 3 via a flange 11.

The pump unit 2 of the tire pressure adjusting device according to the present invention is provided on a part of the flange 11 which is a rotating member.
0 is disposed in parallel with the axle 10, and the cam member 40 is suspended at the end of the axle 10 via a bearing 43 in a non-rotating state with respect to the vehicle.

FIG. 2 shows details of the internal structure of the pump unit 20 and a sectional view of the periphery including the cam member 40. When the flange 11 is eccentric by R from the center of the axle 10,
A support hole 23 into which the cylinder 22 is inserted is provided. A piston 21 is slidably disposed inside the cylinder 22. The air flows from the suction hole 24 of the cylinder 22 to the center port 26 provided at the center of the piston 21 via the annular groove 25 of the piston 21.

The suction valve 27 disposed at the end of the center port 26 is a valve seat 2 press-fitted into the cylinder 22.
8 and is seated by a first spring 29 contracted between the first spring 29 and the second spring 8. Discharge valve 3 arranged at the mouth of valve seat 28
0 is seated by a second spring 32 contracted between the flange 31 and the plug 31 press-fitted into the flange 11.

The cam member 40 is positioned by a C-shaped retaining ring 45 on an outer ring of a bearing 43 fixed to a terminal end of the axle 10 by a nut 44, and is suspended by a weight of a balance weight 46 shown by hatching. Further, if the cover 50 enclosing the entire cam member 40 is attached to the flange 11 with screws 55, dust and waterproofing of the surrounding area can be easily performed.

FIG. 3 is a front view of the cam member 40 as viewed from the slope 42 side. The cam member 40 is supported by a bearing 43 fitted on the axle 10 and suspended vertically from the road surface by the weight of a balance weight 46 shown by hatching. The slope 42 is provided in a ring shape at a position in contact with the tip of the piston 21 eccentric by a distance R from the center of the axle 10. 50 is dust-proof around the cam member 40.
It is an outer peripheral contour of a cover attached to the flange 11 for waterproofing.

The tip of the piston 21 of the pump unit 20 is brought into contact with the slope 42 of the cam member 40, and the thickness of the slope eccentric by R from the center of the axle 10 is L1 <L2.
Then, during one rotation of the flange 11, the piston 21 strokes toward the axle 10 by L2-L1. In order to balance the wheel balance during high-speed driving, a further pump unit 20 is provided at a symmetric position of the axle 10,
Alternatively, it is preferable to provide a counter weight 12 on the flange 11.

In order to maintain the suspended position while the tip of the piston 21 on the pump unit 20 side and the slope 42 of the cam member 40 slide, the thrust of the piston 21 is F, the contact friction coefficient is μ, and the balance weight of the cam member 40 is Assuming that the own weight of 46 is W, the condition of W ≧ Fμ × (L2−L1) / 2R may be satisfied. The air pressure discharged from the pump unit 20 is supplied to the air pipes 53 and 54 via the safety valve 60.
And is fed into the tire 6 under pressure.

When the tip of the piston 21 moves from L1 on the slope 42 of the cam member 40 to L2 while sliding on the slope 42 as the axle 10 rotates, the volume of the chamber 33 of the cylinder 22 decreases, and the compressed air is discharged from the discharge valve 30. To reach the discharge hole 36 of the flange 11 from the slit 34 of the valve seat 28 through the crossway 35 of the cylinder 22, and reach the safety valve 60 through the inside of the tube 52 fixed by the flare nut 51.

When the tip of the piston 21 moves from L2 on the slope 42 of the cam member 40 to L1 while sliding on the slope 42 as the axle 10 rotates, the piston 21 is compressed between the piston 21 and the valve seat 28. When the volume of the chamber 33 expands due to the repulsive force of the third spring 37, the pressure becomes negative, so that the discharge valve 30 is closed and the suction valve 2 is closed.
7 is achieved by opening and sucking air from the suction hole 24. Reference numeral 38 denotes a filter for preventing foreign matter from entering through the suction hole 24.

By repeating the above operation as the axle 10 rotates, the air pressure of the tire 6 is replenished via the air pipes 53 and 54. When the air pressure exceeds a predetermined value, excess air is discharged from the safety valve 60.

FIG. 4 is a detailed sectional view of the internal structure of the safety valve 60 with an adjusting mechanism. The valve body 61 has an inlet port 62 connected to the tube 52 and an air tube 53,
Outlet ports 63, 64 are provided for connection to 54. A valve seat 66 is press-fitted facing a part of the communication path 65 connecting the three ports, and the valve seat 66 is
A poppet 68 holding a ball 67 is pressed by a relief spring 69 and is seated at the mouth of. The other end of the relief spring 69 comes into contact with the adjuster 70 and the relief pressure is set by a position determined by the lock nut 71. When the air pressure supplied from the pump unit 20 exceeds the set pressure, the poppet 68 opens to open the empty space 7.
The air flowing into 2 is discharged through the air holes 73.

As described above, if the position of the adjuster 70 is made variable, the tire pressure can be reduced on a snowy road to increase the contact area and improve the road surface adhesion. The setting of the relief pressure may be performed by using a mechanical adjustment mechanism as shown in FIG. 4 or by adjusting the adjuster 70 by an electric signal by replacing the adjuster 70 with a solenoid.

FIG. 5 shows an example of a tire pressure adjusting device in which a cam member 40a is arranged inside the tire wheel 4.
A tire wheel 4 is mounted on an outer periphery of an axle housing 1 which is a non-rotating member, where the hub 3 is supported by a pair of tapered roller bearings 2 opposed to each other. A rim 5 is provided on the outer periphery of the tire wheel 4 and a known tire 6 is mounted. A brake drum 7 is also mounted on the hub 3, and generates a braking force between the hub 3 and a brake shoe 9 supported by a back plate 8 attached to the axle housing 1. On the other hand, an axle 10 for transmitting a driving force is disposed in the axle housing 1 and has a flange 1.
1 is similar to that of FIG.

The pump unit 20 of the tire pressure adjusting device according to the present invention is mounted on a part of the brake drum 7.
The cam member 40a is fixedly attached to the axle housing 1 via the distance collar 13. The tip of the piston 21 of the pump unit 20 is brought into contact with the slope 42 of the cam member 40a, and the axle 10
The thickness of the slope that is eccentric by R from the center of
If L2, L2-L during one rotation of the brake drum 7
The piston 21 strokes in the direction of the axle 10 by one.
In order to balance the wheel balance during high-speed running, the brake drum 7 is preferably provided with a counterweight 12 indicated by hatching.

The air pressure discharged from the pump unit 20 is distributed to the air pipes 53 and 54 via the safety valve 60 and is sent to the tire 6 by pressure. With the above configuration,
The dustproof / waterproof cover 50 as shown in FIG. 1 can be omitted. Further, the pump unit 20 and the safety valve 6 in FIG.
The structure of 0 is the same as in FIGS.

[0029]

According to the tire pressure adjusting device of the present invention, a pump unit that reciprocates in the same direction as the axle is disposed by utilizing the rotational force of the axle, and one end of the piston of the pump unit is provided on the cam member. The axle was converted into reciprocating motion by compressing the rotation of the axle into reciprocating motion. The thrust of the piston does not decrease during the operation. Since the rotating member has a space for providing an appropriate counterweight, it is easy to balance the wheel balance during high-speed running.

Since a safety valve was provided between the pump unit and the tire to adjust the air pressure to an arbitrary level,
Even if there is a slight air leak in the tire or a change in the temperature of the outside air, it is possible to control the tire to a predetermined air pressure. Further, if the present invention is applied to a double tire, the tire pressures of both tires are kept uniform, so that the load sharing is leveled and uneven wear of the tire can be prevented.

Further, if a manual or automatic adjustment mechanism is added to the safety valve, it is possible to control the air pressure according to the road surface condition.

[Brief description of the drawings]

FIG. 1 is a sectional view in which a tire pressure adjusting device of the present invention is disposed outside a tire wheel.

FIG. 2 is a sectional view of the pump unit of the present invention.

FIG. 3 is a front view of the cam member of the present invention.

FIG. 4 is a sectional view of a safety valve with an adjusting mechanism according to the present invention.

FIG. 5 is a cross-sectional view in which a tire pressure adjusting device of the present invention is disposed inside a tire wheel.

FIG. 6 is an explanatory diagram relating to the magnitude and direction of a combined vector of gravity and centrifugal force for each rotation angle of a tire in a conventional tire pressure adjusting device.

FIG. 7 is a layout sectional view of a conventional pump device.

[Explanation of symbols]

 1: Axle housing 3: Hub 4: Tire wheel 6: Tire 7: Brake drum 8: Back plate 10: Axle 11: Flange 12: Counter weight 13: Distance collar 20: Pump unit 21: Piston 40, 40a: Cam member 42 : Slope 43: Bearing 46: Balance weight 50: Cover 52: Tube 53, 54: Air tube 60: Safety valve 70: Adjuster

Claims (5)

[Claims] 1. A pump unit that reciprocates in the same direction as an axle is disposed on a member that rotates with an axle of a vehicle, and one end of a piston of the pump unit is connected to a cam member that is not rotated with respect to the rotation of a wheel. By contacting the slope, the piston of the pump unit is converted into a reciprocating motion corresponding to the rotational motion of the rotating member, the air sucked from the suction hole of the pump unit is compressed, and the compressed air is passed through the safety valve to the vehicle tire. A tire pressure adjusting device for supplying air. 2. The tire pressure adjusting device according to claim 1, wherein the cam member includes a balance weight disposed outside the tire wheel and suspended from the axle via a bearing. 3. The tire air pressure adjusting device according to claim 1, wherein the cam member is disposed inside the tire wheel, and is fixed to a non-rotating portion on the axle housing side. 4. A safety valve arranged between a pump unit and an air pipe connecting a tire has an adjusting mechanism for arbitrarily increasing or decreasing the tire air pressure.
The tire pressure adjusting device according to any one of the above. 5. The tire pressure adjusting device according to claim 2, wherein a cover for dust and waterproof around the cam member is attached to the rotating member.