Apparatus for detecting tire air pressure for motor vehicle

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for detecting tire air pressure for a motor vehicle, which is operable to lower the speed of the vehicle when the tire air pressure becomes lower than a predetermined value and reliably indicate to a driver of the vehicle that a reduction in tire air pressure has occurred.

2. Description of Background Art

One apparatus for detecting whether the air pressure of a tire for a motor vehicle has been reduced or not is known from Japanese Patent Laid-open No. Hei 9-240446 entitled “BRAKE CONTROL APPARATUS”, for example.

FIG. 4

of the above publication shows a brake control apparatus, wherein when the air pressure of the tire of a left or right front wheel becomes lower than a predetermined value, and the rate of reduction of the air pressure is equal to or higher than a predetermined value based on signals from a left front wheel air pressure sensor

14

and a right front wheel air pressure sensor

15

, a solenoid-operated valve associated with the wheel laterally opposite to the wheel whose tire air pressure has been reduced, i.e., a left front wheel solenoid-operated valve

49

or a right front wheel solenoid-operated valve

50

, is operated to brake the right front wheel or the left front wheel, and a warning unit

8

is actuated.

With the apparatus disclosed in the above publication, however, the wheel is braked only under the condition when the air pressure of the tire is lowered. Accordingly, if the wheel is braked while the throttle opening is increasing, the wheel may not be braked sufficiently and hence the vehicle speed may not be lowered, since the engine output is increasing.

Furthermore, since solenoid-operated valves for braking the wheels are required for the respective wheels, the apparatus has a high cost and a complex process to control those solenoid-operated valves is required.

In addition, it may be difficult for the driver of the vehicle to confirm the warning from the warning unit

8

, if the vehicle is being operated in bright and/or noisy areas.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an apparatus for detecting a tire air pressure for a motor vehicle, which is capable of {circle around (1)} lowering the speed of the vehicle easily with a simple arrangement and {circle around (2)} reliably indicating a reduction in the air pressure to a driver of the vehicle when the tire air pressure becomes lower than a predetermined value.

To achieve the above object, there is provided, in accordance with a first aspect of the present invention, an apparatus for detecting tire air pressure for a motor vehicle includes tire air pressure detecting means for detecting the air pressure of the tire of the motor vehicle, and control means for comparing an actual air pressure detected by the tire air pressure detecting means with a stored air pressure threshold. Furthermore, the engine output is controlled when the actual air pressure becomes lower than the air pressure threshold.

In order to control engine output, several processes are available which include {circle around (1)} adjusting the throttle opening of the engine, {circle around (2)} performing ignition control so as not to increase engine rotational speed beyond a predetermined value, {circle around (3)} cutting off the fuel, and {circle around (4)} changing the resistance of an AC generator. These processes are carried out by control means to control the engine output to lower the vehicle speed.

In accordance with a second aspect of the present invention, an apparatus for detecting tire air pressure for a motorcycle includes tire air pressure detecting means for detecting the air pressure of a tire of a motorcycle, wherein the actual air pressure detected by the tire air pressure detecting means is compared with a stored air pressure threshold. If the actual air pressure becomes lower than the air pressure threshold, a light-emitting member or a sound-generating member disposed on or around an instrumental panel of the vehicle is operated to issue a warning.

When the actual air pressure of the tire drops below the air pressure threshold, the light-emitting member or the sound-generating member disposed on or around the instrumental panel is operated to issue a warning. Even in bright and/or noisy areas, the light-emitting member is easily visually recognizable in the same manner as other various instruments in the instrument panel. This allows a motorcycle driver to be reliably informed of the reduction in air pressure. It should also be noted that it is more preferable to operate both the light-emitting member and the sound-generating member in order to ensure that the driver is informed of the reduction in air pressure under various driving conditions.

According to a third aspect of the present invention, an apparatus for detecting a tire air pressure for a motorcycle includes tire air pressure detecting means for detecting the air pressure of a tire of a motorcycle, wherein the actual air pressure detected by the tire air pressure detecting means is compared with a stored air pressure threshold. When the actual air pressure becomes lower than the air pressure threshold, a light-emitting member or a sound-generating member installed in a driver's helmet is operated to issue a warning.

When the actual air pressure of the tire drops below the air pressure threshold, the light-emitting member or the sound-generating member disposed in the driver's helmet is operated to issue a warning. Accordingly, even in bright and/or noisy areas, the light-emitting member is easily visually recognizable, allowing a motorcycle driver to be informed of the reduction in the air pressure. It should also be noted that it is more preferable to operate both the light-emitting member and the sound-generating member in order to ensure that the driver is informed of the reduction in air pressure under various driving conditions.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1

is a side elevational view of a motorcycle including an apparatus for detecting tire air pressure for a motor vehicle according to the present invention;

FIG. 2

is a view showing a tire air pressure detecting device in the air pressure detecting apparatus according to the present invention;

FIG. 3

is a cross-sectional view of the tire air pressure detecting device in the air pressure detecting apparatus according to the present invention;

FIG. 4

is a block diagram showing a basic arrangement of the air pressure detecting apparatus according to the present invention;

FIG. 5

is a view of display means of the air pressure detecting apparatus according to the present invention;

FIG. 6

is a view of warning means of the air pressure detecting apparatus according to the present invention;

FIG. 7

is a cross-section along the line VII—VII of

FIG. 6

;

FIG. 8

is a flowchart of a control process carried out by the air pressure detecting apparatus according to the present invention;

FIG. 9

is a view showing a wheel on which the tire air pressure detecting device according to the present invention is installed;

FIG. 10

is a cross-section along line X—X of

FIG. 9

;

FIGS. 11A and 11B

are cross-sectional views showing other embodiments of the tire air pressure detecting device of the air pressure detecting apparatus according to the present invention; and

FIG. 12

is a view showing another embodiment of the warning means of the air pressure detecting apparatus according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described below with reference to the accompanying drawings. It should be noted that the drawings should be viewed in the direction in which the reference characters are arranged.

FIG. 1

is a side elevational view of a motorcycle including an apparatus for detecting tire air pressure for a motor vehicle according to the present invention. A motorcycle

10

includes a handle

11

, a front fork

12

and a front wheel

13

. The front fork

12

and front wheel

13

are steerably mounted on a lower portion of the handle

11

. A front cover

14

and a front inner cover

15

cover the lower portion of the handle

11

and an upper portion of the front fork

12

. A floor step

16

is disposed behind a lower portion of the front cover

14

. A body cover

17

extends upwardly from a rear portion of the floor step

16

. A power unit

18

extends rearwardly from within the body cover

17

. A rear wheel

21

is mounted on a rear portion of the power unit

18

. Furthermore, an air suspension device

22

is connected to a rear end of the power unit

18

and a motorcycle frame, not shown, is disposed in the body cover

17

.

An instrumental panel

24

is attached to the handle

11

. The front wheel

13

includes a wheel

25

and a tire

26

. The power unit

18

has an engine that is supplied with fuel from a carburetor

27

. The rear wheel

21

includes a wheel

31

and a tire

32

. A seat

33

is mounted on the body cover

17

.

An apparatus

40

for detecting tire air pressure for a motor vehicle according to the present invention (hereinafter referred to as “air pressure detecting apparatus

40

”) includes a front wheel tire air pressure detecting device

41

attached to the wheel

25

of the front wheel

13

for detecting air pressure and temperature of the tire

26

. A rear wheel tire air pressure detecting device

42

is attached to the wheel

31

of the rear wheel

21

for detecting air pressure and temperature of the tire

32

. An air suspension air pressure detecting device

43

is attached to the air suspension device

22

. A throttle opening adjusting device

44

is attached to the carburetor

27

, for example, for adjusting the throttle opening. The apparatus

40

also includes a control device

45

for receiving signals from the front wheel tire air pressure detecting device

41

, the rear wheel tire air pressure detecting device

42

, and the air suspension air pressure detecting device

43

. In addition, operating warning means, described later on, is provided for controlling the throttle opening adjusting device

44

. Furthermore, a display device

46

responsive to a signal from the control device

45

is provided for displaying the air pressure of the tire

26

of the front wheel

13

, the temperature of the tire

26

of the front wheel

13

, the air pressure of the tire

32

of the rear wheel

21

, the temperature of the tire

32

of the rear wheel

21

, and the air pressure of the air suspension device

22

. Finally, the apparatus

40

includes a warning device, as will be described later on.

The control device

45

is disposed below the seat

33

, for example, and the display device

46

is mounted on the instrumental panel

24

, for example.

FIG. 2

is a first cross-sectional view showing the manner in which a tire air pressure detecting device in the air pressure detecting apparatus of the present invention is installed. The front wheel tire air pressure detecting device

41

will be described below. The rear wheel tire air pressure detecting device

42

is identical in structure to the front wheel tire air pressure detecting device

41

, and will not be described below with reference to FIG.

2

and the following figures.

The tire air pressure detecting device

41

comprises a main detector body

51

and a tire valve

52

attached to the main detector body

51

. The tire valve

52

is opened only when air is supplied into the tire

26

(see

FIG. 1

) and is closed otherwise to prevent air supplied into the tire

26

from flowing out of the tire

26

. The main detector body

51

is disposed in a hole

54

defined in the bottom of a rim

53

. The tire valve

52

is inserted in a valve insertion hole

55

defined in the bottom of the rim

53

. A nut

57

is threaded over an externally threaded outer circumferential surface

56

of the tire valve

52

, thus fastening the tire air pressure detecting device

41

to the wheel

25

.

FIG. 3

is a second cross-sectional view showing the manner in which the tire air pressure detecting device in the air pressure detecting apparatus of the present invention is installed.

The wheel

25

includes a pair of flanges

61

, a pair of bead seats

62

disposed inwardly of the respective flanges

61

, a pair of humps

63

raised inwardly of the respective bead seats

62

, a rim drop

64

lowered between the humps

63

, and the recess

54

defined in the rim drop

64

.

The bead seats

62

serve to hold the beads of the tire

26

(see FIG.

1

).

The humps

63

are annular ridges for preventing the tire

26

from being dislodged from the bead seats

62

of the wheel

25

.

The rim drop

64

is deeply recessed to allow the tire

26

to be attached to and detached from the wheel

25

.

The tire air pressure detecting device

41

is attached to the rim

53

such that the main detector body

51

has an outer surface

51

a disposed inwardly of the bottom surface (described later on) of the rim drop

64

by a distance d. A seal member

67

serves to prevent air from leaking out from the air chamber in the tire

26

. A vent hole

68

(closed by a valve body, not shown) is defined in the tire valve

52

to provide communication between the interior and exterior of the tire

26

.

As described above with reference to

FIGS. 2 and 3

, with the main detector body

51

housed in the recess

54

in the rim

53

, the beads of the tire

26

are prevented from interfering with the main detector body

51

when the tire

26

is installed on or removed from the wheel

25

using a tire changer or the like. Therefore, the main detector body

51

is protected against damage.

It is assumed that a plane formed by circumferentially and transversely interconnecting positions

64

b

where opposite sides

54

a

of the recess

54

and opposite slanted surfaces

64

a

of the rim drop

64

intersect each other represents a bottom surface

64

c

of the rim drop

64

, the distance (radius) from the center of the wheel

25

to the bottom surface

64

c

is represented by R

1

, and the distance (radius) from the center of the wheel

25

to the bottom surface

54

b

of the recess

54

is represented by R

2

.

Referring back to

FIG. 2

, the main detector body

51

is of a curved shape along an inner surface

53

a

of the rim

53

, i.e., a combination of the bottom surface

64

c

of the rim drop

64

and the bottom surface

54

b

of the recess

54

.

The main detector body

51

has an inner surface

51

b

having a radius R

3

of curvature and an outer surface

51

a

having a radium R

4

of curvature. The radii R

1

, R

2

, R

3

, R

4

satisfy the following relationships:

R

4

≦R

1

, {circle around (1)}

R

2

≦R

3

, {circle around (2)}

R

4

≦R

3

{circle around (3)}

It is assumed that the tire air pressure detecting apparatus

41

is to be installed on a wheel having a rim diameter ranging from 10 to 19 inches, for example.

(1) By setting the radius R

4

of the outer surface

51

a of the main detector body

51

to a value smaller than the radium R

1

of the bottom surface

64

c

of the rim drop

64

(see

FIG. 3

) of the wheel having the minimum rim diameter of 10 inches, the outer surface

51

a

of the main detector body

51

does not project outwardly from the bottom surface

64

c

of the rim drop

64

, i.e., R

4

≦R

1

, when the tire air pressure detecting apparatus

41

is installed on any wheels having rim diameters in the range of from 10 to 19 inches.

(2) By setting the radius R

3

of the inner surface

51

b

of the main detector body

51

to a value greater than the radium R

2

of the bottom surface

54

b

of the recess

54

of the wheel having the maximum rim diameter of 19 inches, the inner surface

51

b

of the main detector body

51

does not interfere with the bottom surface

54

b

of the recess

54

, i.e., R

2

≦R

3

, even when the tire air pressure detecting apparatus

41

is installed on any wheels having rim diameters in the range of from 10 to 19 inches.

(3) If R

1

(the dimension of the wheel having a rim diameter of 10 inches) ≦R

2

(the dimension of the wheel having a rim diameter of 19 inches), then since R

4

≦R

1

≦R

2

≦R

3

, R

4

≦R

3

is obtained from the equations (1) and (2).

As described above with reference to

FIG. 2

, since the main detector body

51

is of a curved shape along the inner surface

53

a

of the rim

53

, the main detector body

51

has no projection toward the tire

26

(see FIG.

1

), and hence the beads of the tire

26

are prevented from interfering with the main detector body

51

when the tire

26

is installed on or removed from the wheel

25

. Therefore, the main detector body

51

is protected against damage.

FIG. 4

is a block diagram showing a basic arrangement of the air pressure detecting apparatus according to the present invention. The air pressure detecting apparatus

70

includes tire air pressure detecting means

71

for detecting tire air pressure of the front wheel

13

(see

FIG. 1

) and the rear wheel

21

(see FIG.

1

), tire temperature detecting means

72

for detecting tire temperature of the front wheel

13

and the rear wheel

21

, vehicle speed detecting means

73

for detecting a vehicle speed of the motorcycle

10

(see FIG.

1

), and air suspension air pressure detecting means

74

for detecting air pressure of the air suspension device

22

(see FIG.

1

). Furthermore, the air pressure detecting apparatus

70

includes a timer

75

and first control means

76

for detecting an air pressure signal SP from the tire air pressure detecting means

71

, a temperature signal ST from the tire temperature detecting means

72

, a vehicle speed signal SV from the vehicle speed detecting means

73

, and a suspension air pressure signal SS from the air suspension air pressure detecting means

74

at given time intervals, i.e., at a given frequency, based on a time signal SJ from the timer

75

. In addition, transmitting means

77

are provided for transmitting detected signal data, receiving means

78

are provided for receiving the signal data transmitted from the transmitting means

77

, a warning map

81

is provided for representing a range of tire air pressures and vehicle speeds stored in a ROM for issuing a warning and controlling an engine output when the tire air pressures of the front wheel

13

and the rear wheel

21

are lowered. Furthermore, second control means

82

are provided, as the control means according to the first aspect of the present invention, for generating a display signal SE based on the signal data received by the receiving means

78

, and generating a warning signal SK and an engine control signal SH based on the signal data received by the receiving means

78

and the warning map

81

. In addition, display means

83

are provided for displaying information based on the display signal SE from the second control means

82

, warning means

84

are provided for issuing a warning based on the warning signal SK from the second control means

82

, and engine output changing means

85

are provided for changing engine output based on the engine control signal SH from the second control means

82

.

Each of the tire air pressure detecting means

71

and the air suspension air pressure detecting means

74

includes a pressure sensor, for example, and the tire temperature detecting means

72

includes a temperature sensor such as a thermocouple or the like, for example.

The first control means

76

reduces the frequency of detecting the tire air pressure when the vehicle speed is low, e.g., once in every 15 seconds, increases the frequency of detecting the tire air pressure when the vehicle speed is high, e.g., once in every 0.5 second, and does not detect the tire air pressure when the motorcycle is at rest.

The relationship between the vehicle speed and the detecting frequency may be represented by a linear curve indicative of direct proportion, or may be represented by a quadratic curve such that the detecting frequency increases quadratically as the vehicle speed increases, or may be represented by a curve such that the detecting frequency varies stepwise when the vehicle speed exceeds a certain value, e.g., 80 km/h.

By lowering the detecting frequency with the first control means

76

when the vehicle speed is low, the consumption of the battery is reduced. In addition, by not detecting the tire air pressure when the motorcycle is at rest, the consumption of the battery is further reduced. The tire air pressure detecting apparatus

41

(see

FIG. 1

) can thus be used for a prolonged period of time.

By increasing the detecting frequency with the first control means

76

when the vehicle speed is high, a reduction in the tire air pressure can be detected earlier, allowing a warning to be issued and engine output to be controlled quickly.

The engine output changing means

85

is a device for changing the engine output in response to the engine control signal SH. For example, the engine output changing means

85

may comprise an actuator that operates based on a negative pressure or a hydraulic pressure in the engine or is in the form of a motor or a solenoid, the actuator being mounted on a throttle shaft of the engine for actuating the throttle shaft, or an ignition device under ignition control, or a device for cutting off fuel, or a device for changing the resistance of an AC generator.

Each of the tire air pressure detecting devices

41

,

42

shown in

FIG. 1

includes, as shown in

FIG. 4

, the tire air pressure detecting means

71

, the tire temperature detecting means

72

, the vehicle speed detecting means

73

, the timer

75

, the first control means

76

, the transmitting means

77

, and a battery, not shown, serving as a power supply for these means.

The air suspension air pressure detecting device

43

shown in

FIG. 1

includes the air suspension air pressure detecting means

74

shown in FIG.

4

. The throttle opening adjusting device

44

shown in

FIG. 1

includes the engine output changing means

85

shown in FIG.

4

. The control device

45

shown in

FIG. 1

includes the second control means

82

shown in FIG.

4

. The display device

46

shown in

FIG. 1

includes the display means

83

shown in FIG.

4

.

The warning means

84

shown in

FIG. 4

includes a lamp and a speaker in a helmet, as will be described later on.

FIG. 5

is a front elevational view of the display means

83

of the air pressure detecting apparatus according to the present invention.

In

FIG. 5

, the display means

83

has a tire air pressure indicator

91

, an air pressure value display unit

92

, and a tire temperature indicator

93

.

The tire air pressure indicator

91

, the air pressure value display unit

92

, and the tire temperature indicator

93

selectively display values from the front wheel

13

(see

FIG. 1

) and the rear wheel

21

(see FIG.

1

).

FIGS. 6 and 7

are views showing the warning means of the air pressure detecting apparatus according to the present invention.

FIG. 6

is a side elevational view of the warning means, and

FIG. 7

is a cross-sectional view taken along line VII—VII of FIG.

6

.

The warning means

84

includes a warning signal receiver

97

for receiving a signal transmitted from the second control means

82

(see FIG.

4

), lamps

98

as a light-emitting member for issuing a warning with light, and speakers

101

as a sound-generating member for issuing a warning with sound. The warning signal receiver

97

, the lamps

98

, and the speakers

101

are mounted in a driver's helmet

96

.

In

FIG. 7

, the lamps

98

are mounted on an inner edge of an upper side of a front opening

102

in the helmet

96

. The lamps

98

should preferably be capable of emitting highly visible light of red, orange, yellow, or the like.

The speakers

101

are embedded in inner walls of the helmet

96

which correspond to the positions of the ears of the driver.

The speakers

101

should preferably emit a voice sound, for example, for drawing attention to and alerting the driver.

As described above, the present invention resides in that the tire air pressure detecting means

71

detects an air pressure of the tires

26

,

32

of the motorcycle

10

, the actual air pressure Pt (described later on with reference to

FIGS. 11A and 11B

) detected by the tire air pressure detecting means

71

and a stored air pressure threshold Pb (described later on with reference to

FIGS. 11A and 11B

) are compared with each other, and when the actual air pressure Pt drops below the air pressure threshold Pb, the lamps

98

and the speakers

101

mounted in the driver's helmet

96

are operated to issue a warning.

When the actual air pressure Pt of the tires

26

,

32

drops below the air pressure threshold Pb, the lamps

98

and the speakers

101

mounted in the driver's helmet

96

are simultaneously operated or either the lamps

98

or the speakers

101

are operated to issue a warning. Even in bright and noisy areas, since the lamps

98

in the helmet

96

are highly visible, the driver of the motorcycle

10

can be reliably informed of the reduction in tire air pressure.

By generating a voice sound as a warning from the speakers

101

, the content of the warning can be indicated to the driver reliably and gently. For example, when a warning is issued while the motorcycle is running, the driver can act calmly accordingly.

FIG. 8

is a flowchart of a control process carried out by the air pressure detecting apparatus according to the present invention. In

FIG. 8

, “STxx” represents a step number as follows:

ST

01

. . . The vehicle speed detecting means detects a vehicle speed V;

ST

02

. . . The first control means sets a detecting frequency for the tire air pressure Pt based on the obtained vehicle speed signal;

ST

03

. . . The tire air pressure Pt, the tire temperature Tt, and the air suspension air pressure Ps are detected at the detecting frequency thus set;

ST

04

. . . The transmitting means transmits the detected data;

ST

05

. . . The receiving means receives the detected data transmitted from the transmitting means;

ST

06

. . . The second control means displays the detected data received by the receiving means on the display means;

ST

07

. . . The second control means determines whether the tire air pressure Pt received as the actual air pressure by the receiving means is lower than the tire air pressure threshold Pb or not, i.e., Pt<Pb;

If Pt<Pb (NO), control goes back to ST

01

;

If not Pt<Pb (YES), control goes to ST

08

; and

ST

08

. . . The warning means issues a warning, and the engine output changing means changes an engine output to lower the vehicle speed.

If the air pressure detected by the tire air pressure detecting means

71

and the air suspension air pressure detecting means

74

in

FIG. 4

is not constant, but varies, due to road conditions and motorcycle vibrations, then the first control means

76

or the second control means

82

averages the detected data or uses a noise filter to obtain highly accurate air pressure data.

As described above with reference to

FIGS. 1

,

4

, and

8

, the air pressure detecting apparatus includes the tire air pressure detecting means

71

for detecting a tire air pressure of the tires

26

,

32

of the motorcycle

10

, and the second control means

82

for comparing the actual air pressure Pt detected by the tire air pressure detecting means

71

and a stored air pressure threshold Pb with each other, and controlling an engine output when the actual air pressure Pt drops below the air pressure threshold Pb.

When the actual air pressure Pt drops below the air pressure threshold Pb, the engine output can be reduced by reducing the throttle opening of the engine to lower the vehicle speed.

Therefore, the vehicle speed can easily be lowered by reducing the throttle opening. In order to reduce the throttle opening, only one throttle opening adjusting means in the form of an actuator that operates based on a negative pressure or a hydraulic pressure in the engine or in the form of a motor or a solenoid is mounted on the throttle shaft. Such a simple arrangement assures safety of the motorcycle.

The air pressure detecting apparatus

40

includes a smaller number of parts, i.e., the tire air pressure detecting means

71

and the second control means

82

for reducing the engine output under certain conditions, than the conventional air pressure detecting apparatus. The air pressure detecting apparatus

40

can hence easily be reduced in size and cost.

FIGS. 9 and 10

show a wheel on which the tire air pressure detecting device according to the present invention is installed.

FIG. 9

is a side elevational view of the wheel, and

FIG. 10

is a cross-sectional view taken along line X—X of FIG.

9

.

In

FIG. 9

, the wheel

25

includes a weight

69

integral with the rim

53

for counterbalancing the tire air pressure detecting device

41

, disposed 180° opposite to the position of the tire air pressure detecting device

41

(see FIG.

3

), i.e., the recess

54

(see FIG.

3

).

In

FIG. 10

, the weight

69

projects from the rim

53

toward the center of the wheel

25

.

As described above, the present invention resides in that the wheel

25

includes the integral weight

69

for counterbalancing the tire air pressure detecting device

41

, disposed 180° opposite to the position of the tire air pressure detecting device

41

on the rim

53

.

With the weight

69

being integral with the rim

53

, the wheel

25

can easily be balanced without the need for a special counterbalance attached or applied to the wheel

25

for balancing the wheel

25

. Therefore, the workability of the wheel

25

can be improved.

FIGS. 11A and 11B

are cross-sectional views showing other embodiments of the tire air pressure detecting device of the air pressure detecting apparatus according to the present invention.

In

FIG. 11A

, a wheel

121

includes a rim

122

and a spoke

123

extending from the rim

122

and connected to a hub, not shown. A tire air pressure detecting device

126

is mounted on a mount

124

of the spoke

123

.

The tire air pressure detecting device

126

includes a main detector body

127

and a tire valve

128

attached to the main detector body

127

. The main detector body

127

is disposed in the spoke

123

, and the tire valve

128

is inserted in a valve insertion hole

131

defined in the mount

124

. A nut

133

is threaded over an externally threaded outer circumferential surface

132

of the tire valve

128

, thus fastening the tire air pressure detecting device

126

to the spoke

123

of the wheel

121

. A seal member

134

serves to prevent air from leaking out from the air chamber in the tire and the spoke

123

.

The main detector body

127

is identical in structure to the above main detector body

51

(see FIG.

3

), and will not be described below.

In

FIG. 11B

, a wheel

141

includes a rim

142

and a spoke

143

extending from the rim

142

and connected to a hub, not shown. The spoke

143

has a land

144

disposed therein, and a tire air pressure detecting device

146

is mounted on the land

144

by screws

147

(the screw

147

behind the illustrated screw

147

is omitted from illustration). The tire air pressure detecting device

146

has a flange

148

disposed on a side thereof.

The tire air pressure detecting device

146

is separate from a tire valve. The tire air pressure detecting device

146

is structurally identical to the main detector body

51

(see

FIG. 3

) and the main detector body

127

(see

FIG. 11A

) and will not be described below.

FIG. 12

is a view showing another embodiment of the warning means of the air pressure detecting means according to the present invention. The warning means includes a light-emitting member which may be a lamp such as front turn signal lamps

151

, rear turn signal lamps

152

, and a stop lamp

153

.

Specifically, when the actual air pressure Pt of a tire

156

of a front wheel

155

and a tire

158

of a rear wheel

157

drops below the air pressure threshold Pb, control means (not shown) of an air pressure detecting device (not shown, but identical to the air pressure detecting device

40

shown in

FIG. 1

) on a motorcycle

150

outputs a signal to flicker or turn on the front turn signal lamps

151

and rear turn signal lamps

152

as hazard lamps (danger indicator lamps), and simultaneously or independently flicker or turn on the stop lamp

153

.

In this manner, a malfunction of the motorcycle

150

while it is running or at rest can reliably be indicated to the rider or other motor vehicles or pedestrians to allow them to avoid the malfunction with ease.

Since the front turn signal lamps

151

, the rear turn signal lamps

152

, and the stop lamp

153

on the motorcycle

150

are used as the warning means, no special warning means needs to be added to the motorcycle

150

, and hence the cost of parts of the air pressure detecting apparatus can be reduced.

In addition to the stop lamp

153

, a tail lamp (not shown) may be flickered (or turned on).

Embodiments other than the above embodiments will be described below.

The warning map may be represented by a linear line such that the air pressure rate is constant regardless of the vehicle speed, a curve such that the rate of increase of the air pressure rate becomes progressively smaller as the vehicle speed increases, or a curve such that the air pressure rate increases stepwise as the vehicle speed increases.

The light-emitting member of the warning means includes a lamp or lamps in the above embodiments. However, the light-emitting member may comprise an LED or a liquid crystal with back light. The sound-generating member includes a speaker or speakers in the above embodiments. However, the sound-generating member may include a buzzer, a bell, a siren, a drum, or a whistle.

The warning means may include a vibration-generating member for issuing a warning with vibrations instead of or in addition to the light-emitting member and the sound-generating member.

The vehicle speed detecting means may not be included in the tire air pressure detecting apparatus, but may be independently mounted on a wheel of the vehicle.

The engine output may be changed by a fuel supply quantity adjusting valve disposed in the intake passage of the engine for reducing the quantity of supplied fuel or cutting off supplied fuel, or by sending a fuel supply quantity adjusting signal or a fuel cutting signal from the second control means

82

to an engine control unit to reduce the quantity of supplied fuel or cutting off supplied fuel, instead of the throttle opening changing means. In addition, means for turning off or retarding ignition may be employed.

In the above embodiments, the front wheel tire air pressure detecting device

41

and the rear wheel tire air pressure detecting device

42

are structurally identical to each other. However, the wheel tire air pressure detecting devices

41

,

42

may be of different shapes and dimensions to match the diameters and widths of the tires and wheels.

The warning means including the light-emitting member and the sound-generating member may be installed on or around the instrumental panel

24

shown in

FIG. 1

, rather than within the helmet. With this arrangement, the warning means can be easily visually recognized as well as the various instruments in the instrument panel, and the warning sound can easily heard. The warning sound may be in the form of a voice sound.

The air pressure detecting apparatus

40

is not limited to use on motorcycles, but may be used on three-wheeled vehicles and four-wheeled vehicles.

The present invention thus constructed offers the following advantages:

The tire air pressure detecting apparatus for a motor vehicle according to the first aspect of the present invention includes a small number of constituent elements including tire air pressure detecting means and control means for reducing engine output under certain conditions. The tire air pressure detecting apparatus can hence easily be reduced in size and cost.

The tire air pressure detecting apparatus according to the second aspect of the present invention includes tire air pressure detecting means for detecting the air pressure of a tire of a motorcycle, and wherein actual air pressure detected by the tire air pressure detecting means is compared with a stored air pressure threshold, and when the actual air pressure becomes lower than the air pressure threshold, a light-emitting member or a sound-generating member disposed on or around an instrumental panel is operated to issue a warning. When the actual air pressure of the tire drops below the air pressure threshold, the light-emitting member or the sound-generating member disposed on or around the instrumental panel is operated to issue a warning. Accordingly, even in bright and noisy areas, the light-emitting member is easily visually recognizable as well as other various instruments, allowing a motorcycle driver to be reliably informed of the reduction in the air pressure.

If both the light-emitting member and the sound-generating member are operated, then the effect of the warning is increased further.

The tire air pressure detecting apparatus for a motor vehicle according to the third aspect of the present invention includes tire air pressure detecting means for detecting the air pressure of a tire of a motorcycle, and wherein actual air pressure detected by the tire air pressure detecting means is compared with a stored air pressure threshold, and when said actual air pressure becomes lower than the air pressure threshold, a light-emitting member or a sound-generating member installed in a driver's helmet is operated to issue a warning. Accordingly, even in bright and noisy areas, the light-emitting member is easily visually recognizable, allowing a motorcycle driver to be reliably informed of the reduction in the air pressure.

If both the light-emitting member and the sound-generating member are operated, then the effect of the warning is increased further.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Number	Date	Country	Kind
2000-174515	Jun 2000	JP
2001-017852	Jan 2001	JP

Number	Name	Date	Kind
4763709	Scholer	Aug 1988	A
5805120	Yamada et al.	Sep 1998	A
6011463	Cormier, Sr.	Jan 2000	A
6226583	Iwata	May 2001	B1
6275148	Takamura et al.	Aug 2001	B1
6446023	Ernst	Sep 2002	B1

Apparatus for detecting tire air pressure for motor vehicle

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (2)

US Referenced Citations (6)

Foreign Referenced Citations (1)