JPS588411A - Controller for air pressure of vehicle tire - Google Patents

Abstract

PURPOSE:To improve steering properties and the feeling of ride, by detecting the air pressure of the tire of a vehicle, the load upon the tire, the level of vibration during the movement and the speed of the vehicle to control the tire to such air pressure as to provide a required cornering force. CONSTITUTION:A tire air pressure controller 1 comprises means 7, 8 for detecting the air pressure of the front and rear tires 2-5 of a vehicle 6, means 9-12 for detecting the load on the tires, means 13-16 for detecting the vertical vibrational acceleration of the wheels, a means 17 for detecting the speed of the vehicle and a means 18 for controlling the air pressure of the tires on the basis of the signals detected by the former means. The means 7 for detecting the air pressure of the front tires 2, 3 is provided in a front tire air pressure measuring chamber 19. The means 8 for detecting the air pressure of the rear tires 4, 5 is provided in a rear tire air pressure measuring chamber 20. The signals are transmitted from the detection means 7-17 to the control means 18 as shown by one-dot chain lines. Piping for pressurized air is provided as shown by a dotted line 21.

Description

[Detailed description of the invention] The present invention relates to a tire pressure control device for a vehicle.

Examples of conventional vehicle tire pressure control devices include:
Jikko 46-. There is one disclosed in No. 18171. This includes a solenoid valve that fills or releases air from inside the tire, and a pressure switch and a manual switch that operate by detecting the air pressure of the tire to operate the solenoid valve.

However, such conventional tire pressure control devices for vehicles were designed to control tire pressure by simply detecting the tire pressure, so it is difficult to control the number of passengers, loading conditions, and driving conditions. In some cases, there has been a problem in that it is not possible to achieve satisfactory vehicle maneuverability, running stability, ride comfort, etc.

This invention was made by focusing on these conventional problems, and in addition to the tire air pressure, the load on the tires, and the vibration level when the vehicle is running (vehicle body vertical vibration acceleration or suspension system unsprung mass). R of vertical vibration acceleration
, M, S (double average) values, etc.) and vehicle speed, and control the tire air pressure based on these values to solve the above problems.

In general, the maneuverability (turning performance) of a vehicle is determined by the balance between the centrifugal force applied to the vehicle during turning and the cornering force of the tires generated from the front and rear wheels. It shows the rate at which the cornering force of the tire changes with respect to the change in , and takes a nearly constant value in a range where the slip angle is small.

). Therefore, the cornering force is thicker (the same cornering force is generated at a smaller slip angle, and the vehicle can turn against a comparable centrifugal force, so the vehicle can turn with a smaller steering angle).・
It is known for its sharp steering wheel and excellent maneuverability (turning performance). On the other hand, as shown in Figure 1,
It is known that tires have a characteristic that the air pressure that maximizes their cornering power changes depending on the load applied to the tires.

Therefore, in the tire pressure control device of the present invention, based on the above-mentioned facts, a means for detecting the tire air pressure, a means for detecting the load applied to the tire, and a required cornering power for the tire can be obtained based on these. and a control means for controlling the air pressure of the tire,
The air pressure of the tires is controlled so that the cornering power of the tires is around the maximum value relative to the load applied to the tires. As a result, the tire pressure control device of the present invention can always maintain cornering power near the maximum value even when the load on the vehicle changes, thereby providing excellent maneuverability (turning characteristics) of the vehicle. I can do it.

In general, the driving stability of a vehicle is determined by Statec C, which is the cornering power of the front or rear tires, respectively, as shown in Figure 2, and a and b, which are the cornering power of the front or rear tires, respectively, as shown in Figure 2. It is known that the distance from the point of application of force on the road surface to the center of gravity C and G of the vehicle is expressed by The point of action of the resultant force is located behind the center of gravity C and G of the vehicle, and when the vehicle is traveling straight and some disturbance occurs, a restoring moment acts to return the vehicle to its previous state, so it has running stability. It has been known.

Furthermore, as shown in FIG. 1, it is known that the cornering power of a tire changes depending on the internal pressure and load of the tire.

Therefore, in the tire air pressure control device of the present invention, based on the above-mentioned facts, a means for detecting the air pressure of the tire, a means for detecting the load applied to the tire, and a means for detecting the load distribution of each wheel based on these, and a control means for controlling tire air pressure so that the tires can obtain cornering power that makes the static margin S positive, even if the number of passengers or the loading condition changes, the cornering power that makes the static margin S positive Control tire pressure so that As a result, with the tire air pressure control device of the present invention, the running stability of the vehicle can be improved even if the number of passengers or the loading condition changes.

Additionally, the ride quality of a vehicle generally deteriorates when the level of vibration transmitted from the road surface to the vehicle body when the vehicle is running is large.

It is known that this vibration transmission from the road surface increases as the tire air pressure increases, and decreases as the tire air pressure decreases.

Therefore, based on the above-mentioned facts, the tire air pressure control device of the present invention includes means for detecting tire air pressure, means for detecting the load/weight on the tire, and means for detecting the vibration level when the vehicle is running. , and a control means for controlling tire air pressure based on these, for example,
The tire air pressure is controlled to obtain cornering power that makes the static margin S positive, and the tire air pressure is lowered when the level of vibration transmitted from the road surface to the vehicle body is large, such as when driving on rough terrain. to correct. Therefore, with the tire air pressure control device of the present invention, both the running stability of the vehicle and the riding comfort of the vehicle can be improved.

Additionally, when a vehicle is running at high speed, it is generally necessary to increase the air pressure in the tires compared to when the vehicle is running normally to prevent standing wave phenomena and the like, thereby increasing safety during high-speed running.

Therefore, based on the above-mentioned facts, the tire air pressure control device of the present invention includes a means for detecting tire air pressure, a means for detecting the load applied to the tire, a means for detecting vehicle speed, and a means for detecting the tire air pressure based on these. The tire is equipped with a control means for controlling air pressure, and controls the air pressure of the tire so that the required cornering power is obtained for the load, and also controls the air pressure to be higher during high-speed driving than during normal driving. As a result, the tire air pressure control device of the present invention can improve running stability, especially safety during high-speed running.

The present invention will be explained below based on the drawings.

FIG. 3.4.5 is a diagram showing a tire air pressure control device for a vehicle according to an embodiment of the present invention. First, the configuration will be explained. As shown in FIG. 3, the tire air pressure control device (1) of this embodiment has pneumatic tires (21 (3)
1 (41f5), means for detecting the air pressure of the front and rear tires (2) (3) and (41 (5)) (force and (81) and each tire (2)
(Means for detecting the load applied to 31 (41 (51) (9)
(101(1+)αδ and means for detecting the vibration acceleration of each wheel in the vertical direction of the vehicle body<+31 Q4j (+
51 (+81), a means aη for detecting vehicle speed, and a tire (21 (31 (4)
A control means 08 for controlling the air pressure of 1+51 is provided.

Means for detecting the air pressure of the front left and right tires (21 (31)
7) are installed in the front wheel side pressure measurement chamber Ql connected to the front left and right tires f21 (31), and are installed in the front left and right tires f21 (31).
The means (8) for detecting the air pressure of 41 (51) is provided in the rear left and right tires (rear wheel side pressure measurement chambers connected to 41 (5)).

Means for detecting the load applied to each tire f2) (31 (41+51) The structure is such that a load cell is inserted into the coil spring or the amount of deflection of these coil springs is measured. Means Q31 for detecting the vibration acceleration of each wheel in the vertical direction of the vehicle body (
(IIQI
)02) is used in combination. The vehicle speed detecting means aη is provided at the speedometer cable outlet of the transmission and is configured to count the rotation of the speedometer cable in pulses and convert it into the vehicle speed. In the figure, a dashed line indicates a signal transmission path between each detection means and the control means α. (2υ indicates a pressure air system. Pressure air system (20 is an air compression pump driven directly by the engine or an electric motor, a pressure storage chamber c!moat where the pressure air generated by the air compression pump @ is accumulated, Two 3-position switching valves (24 (c), 3-position switching valve (24) C) operated by a signal output from the control means (181)
The front wheel side or rear wheel side pressure measuring chamber (II (201), which is connected to the pressure accumulator chamber Q through two (2) A rotary joint @ (9) that connects the inside of (3) and the front wheel pressure measurement chamber 09 via piping, and similarly allows the rear left and right tires (41 (51) attached wheels to rotate freely. A rotary joint (28) C'S supports the tire (4) (5) and connects the inside of the tire (4) (5) with the pressure measurement chamber on the rear wheel side via piping.
has. The dotted line in the figure shows the path of pressurized air.

As shown in FIG. 4 ABC, the three-position switching valve 024) (c) has a spring center type configuration, and when a signal to maintain the tire air pressure at a constant level is input from the control means 08, no operating force is applied. Due to its own spring force, the pressure measuring chamber a9■ and the pressure accumulating chamber (2
31 and the atmosphere. Also, 3 position switching valve CI! 41 (c) indicates that when a signal to increase the tire air pressure is given from the control means 0 mark by human input, the operating force acts and the tire moves to position ① in Figure 4B,
The pressure measurement chamber (231) is connected to the pressure accumulation chamber (231).The three-position switching valves Q (a) and (c) receive a signal from the control means 08 to reduce the tire air pressure. At this time, an operating force is applied to move the pressure measuring chamber 09■ to the 1st position (C) in FIG.

Next, with reference to the block diagram of the control means θ shown in FIG. 5, the configuration of 0 types of control means and the operation of the air pressure control device (1) will be described together. This control means a8 controls the tire (21(3)(
4) In addition to controlling the air pressure in (5) to ensure driving stability, when the level of vibration transmitted from the road surface to the vehicle body is large, such as when driving on rough terrain, the tire air pressure is corrected to a lower level to improve ride comfort. At the same time, we aim to achieve this goal. That is,
Control means 0, the front left and right tires (21 (31) detecting means (91 (II) load signal Wf
+, enter Wf 2 and calculate the front wheel load, Wf =
The front wheel load calculation circuit Gυ that calculates Wf + + Wf 2 and the load signal Wr of the detection means QllQ21 that similarly detects the load applied to the rear left and right tires (41 (5)
+, enter Wr 2 and calculate the rear wheel load Wr - Wr 1
+ Wr 2 is calculated by the rear wheel load calculation circuit Gυ (321), and the front and rear wheel loads Wf and Wr calculated in the front and rear wheel load calculation circuit Gυ (321) are stored in the memory 01 (ro ) is stored as follows. That is, when a signal indicating that the vehicle speed ν is zero is input from the vehicle speed detecting means (17) to the trigger circuit (351), a storage trigger is generated and each arithmetic circuit OυC3 By inputting the contents of the hot water into the memory (c) (goods), the front and rear wheel loads Wf at rest can be calculated.

Wr is now stored. (3fil is a center of gravity position calculation circuit, which calculates the center of gravity position of the vehicle from the static front and rear wheel loads Wf and Wr stored in memo IJ-(33) and (34), and calculates the cornering force Cf, which will be described later.
, Cr is input to the resultant force action position calculation circuit 07). (to) is a static margin setting circuit, which not only performs static margin setting, but also adjusts its size to select the level of running stability. The static margin S and the center of gravity position (load distribution) G (''a -) b) set in this static margin setting circuit C381 are input to the cornering force resultant action position calculation circuit C37), and this static The cornering force resultant action position (front and rear wheels) required to obtain the margin S is calculated.

OI is the turning ability setting circuit, and the memo IJ-H (341
The front and rear wheel loads Wf and Wr are manually calculated and the total load W =
In addition to finding Wf-1-Wr, the installed tire (
21(3) (according to 41(5), front tire (2+
(3) Cornering power Cf and rear tire (4
The value of the sum Cf+Cr of the cornering power Cr of 1+51 is the front wheel load Wf and the rear wheel load Wr from the memory (b).
The total load W is obtained by manually inputting the signal, and the sum of cornering forces Cf + Cr (-KW) is obtained by multiplying this total load W by a preset coefficient K for an average road surface.

Note that this coefficient may be set so that the driver can select it depending on the road surface. +41 is a cornering power calculation circuit, which calculates the resultant force of the cornering force determined by the sum of the cornering powers set in the turning ability setting circuit 0Y Cf+ (:'r(-KW) and the resultant force action position calculation circuit 07 of the cornering force) Position of action (distribution of cornering power between front and rear wheels) Front tire required to obtain gin S (cornering power Cf of 21 (31) = (
1-C) K, W, and the cornering power Cr=CKW of the rear tire (41f5) are calculated. (4υ is a tire pressure calculation circuit, and a cornering power calculation circuit (front and rear tires (21 (31 and (41
(5) The air pressure 1'f and P' are calculated.In other words, the tire air pressure calculation circuit (tire f2 attached to 4υ) (31 (according to 41 (5), the wheel load Wf , the cornering power Cf, Cr and tire pressure P that change according to Wr as a parameter.
The function Pf, r=P (C
f, r Wf, r) are stored, and the front and rear wheel cornering powers Cf, Cr input from the cornering power calculation circuit 4 are substituted with the front and rear wheel Wf, Wr input from the memory (c)■. Then, find the air pressures Pf and Pr of the front and rear tires (2) (31 and (4) + 51) necessary to generate these cornering powers Cf and Cr.The function P is the wheel load Wf,
The upper limit tire air pressure is set according to Wr, and the tire is protected by preventing excessive air pressure from being supplied to the tire (2+ (31 (41 (5)).
Although the front and rear tires (2), (3) and f41+51 are set to the same value, different functions may be stored for each front and rear tire. (421 is an air pressure correction circuit,
If the front or rear tires (2) (31 (41 (5)) become extremely low or high pressure when the load distribution is extremely unbalanced, the tires may generate abnormal heat and cause trouble, so please check the air pressure. The tire pressure calculation circuit (4υ) controls the air pressures Pf and Pr based on the function F of the tire pressure calculation circuit (4υ) only within these limits by setting the upper and lower limits. )(41
(If the air pressure Pf or P' found by the function F is between the lower limit air pressure and the upper air pressure H as shown in the figure in accordance with 51, the air pressure value Pf or Pr is output as is, and the air pressure Pf Or, if Pr is less than or equal to the lower air pressure limit, the value of the lower air pressure limit is changed to the air pressure Pf or Pr.
A function Bf, r = 9 (Pf, r) is stored that outputs the value of the upper limit air pressure I4 when the value is greater than the upper limit air pressure H, and the air pressure Pf obtained by the tire air pressure calculation circuit (4I).

Air pressure Bf or Br after correcting Pr as described above
Output as . In addition, this air pressure correction circuit (421) changes the upper limit air pressure H of the function g to a lower value h when the level of vehicle body vibration is large. In other words, the means (131) for detecting the vibration acceleration of the wheel in the vehicle body vertical direction (1411
51α clause outputs vibration acceleration aft, af2.
ar+.

The circuit (43114 滲(45)(46)) that calculates the square root of the mean square of ar20 (RoM, S) value, and these circuits (
4 → (44) (Circuit for calculating the average values Af and Ar of the R and MS values for each front and rear wheels determined by 4f9 (4η (4 barrels, this average value Af, Ar and the reference level Afo,
Equipped with a comparator (491 (50)) that compares the vibration with Set the air pressure H to a lower value h.

Note that the function I may be different for each of the front and rear wheels.

51) and 521 are subtractors, and the means for detecting air pressure (force) and the front and rear tires detected by (8) (21(
31 and (41 (51 actual air pressures P'f and P
'r and the air pressure correction circuit (air pressure B output by 421)
Difference between f and Br ef = Bf - P'f and e
r = Br - P'r is calculated respectively. (53
1 and 54) are dead zone setting circuits, and ef and e
The difference Ef-1ef1-1 between the absolute value of r and the positive constant l and Er = 1erl-l are calculated.

Judgment circuits 65) and (g) are Ef or E, respectively.
If r is zero or negative, set the 3-position switching valve (2 (A) or (C)) to the first position, and set the front and rear tires (2
) (31 or (41+51) air pressure is maintained at the same value. On the other hand, judgment circuit 57) and 5B c-i respectively judge that Ef or Er is positive, and if Ef or Er is positive, sign is determined. Circuit (591- and 6
0M determines the sign of ef and e''. If the sign discrimination circuit determines the sign of ef or er as positive, the actual air pressure P'f or P'r determines the required cornering power Cf or Cr. Since the air pressure is lower than the air pressure Bf or Br necessary to obtain
or (a), the front and rear tires (21
The air pressure of (31 or (4051) is increased. Conversely,
If the sign discrimination circuit (5 wings) discriminates the sign of ef or er as negative, the actual air pressure Pf or P'
Since r is higher than the air pressure Bf or Br required to obtain the required cornering power Cf or Cr, the 3-position switching valve (2) or (c) is set to the is communicated, and the air pressure of the front and rear tires (21 (3) or (41 (51) Tires to do (2)
(3) (4) Even if the air pressure in (51) is controlled, there is actually a limit to the range in which the cornering power of the tire can be changed, so the desired static margin S may not be obtained. In this case, a warning is issued to alert the driver. (64) is a cornering power detection circuit that constitutes a part of the warning device, and the means for detecting air pressure (7) + 81 detects the cornering power. Front and rear tires (2
H3) and (41+51 air pressures P'f, P'r and front and rear wheel loads Wf, W output by memory (c) and (b)
r manually, tire (21 (31 and (4) + 5
) to detect the actual cornering powers Cf' and Cr'. In other words, this circuit is equipped with tires (
21 (31 (according to 41 (5), as shown in the figure, the wheel loads Wf, Wr are used as parameters and the cornering powers Cf', Cr' and tire air pressures that change accordingly)'f, P'r. C', r'=f
(P'f, r Wf, r) is stored,
Front and rear wheel loads Wf, W from memory C33C341
r and the detection means (71 (81) air pressure Pf, Pr
By substituting , tires (2), (3) and +
41 (Cornering power Cf' that 51 actually has
, Cr' are detected. 65) and the tire detected by the bower detection circuit example (21+31 and (
The cornering power Cf' that 41(5) actually has,
Cr' and the cornering power calculation circuit (Cf and Cr required to satisfy the static margin S determined by 4G are compared, and Cf and C
If f' is not equal to C' or C' is not equal to C', a warning device is activated to alert the driver to driving stability.

FIG. 6 is a block diagram of a control means according to another embodiment of the present invention. This control means detects the tire air pressure, the load on the tire, and the vehicle speed, and controls the tire air pressure so as to obtain cornering power that makes the static margin S positive, and also controls the tire air pressure during normal driving when driving at high speed. The tire pressure is controlled to be higher than usual to improve driving stability, especially at high speeds. That is,
This control means Qi1. In the means a for detecting the vehicle speed ν, and when the vehicle speed ν reaches a constant vehicle speed V or more, the air pressure correction circuit (
A discriminant 1 path 6η that increases the function S of 43 by ΔB as a whole compared to the value when the vehicle speed is less than 7, as shown by the dashed line.
has. Therefore, in this control means OS, when the heavy speed ν is higher than ■, the tire air pressure is increased by ΔB. For other configurations and functions, see 3.4.
．． Since it is similar to the embodiment shown in FIG. 5, the same parts are given the same reference numerals and the explanation will be omitted.

As explained above, according to the present invention, the tire air pressure, the load on the tires, or in addition to these, the vibration level and vehicle speed when the vehicle is running are detected, and the tire air pressure is controlled based on these values. This has the effect of controlling the vehicle's maneuverability, running stability, and ride comfort to a satisfactory level even if the number of passengers, loading conditions, and driving conditions change.

Furthermore, in addition to the above-mentioned effects, the embodiment shown in Fig. 3.4.5 is equipped with a warning device, so it has the effect of alerting the driver to the running stability of the vehicle.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between vehicle tire air pressure and cornering power (load applied to the tire) as a parameter; Figure 2 is a schematic diagram of the vehicle to explain the static margin S of the vehicle; Figure 3 4 is a schematic diagram showing a tire pressure control device for a vehicle according to an embodiment of the present invention, and FIGS. Schematic diagram showing,
FIG. 5 is a block diagram of the control means of the tire pressure control device for a vehicle according to this embodiment, and FIG. 6 is a block diagram of the tire pressure control means for a vehicle according to another embodiment of the present invention. (1)...Tire pressure control device +21 (31(
41 (51... Tire (force (8)... Means for detecting air pressure (91QI(I[+21... Means for detecting load applied to tires) 031Q4H151 (+e... Means for detecting vibration acceleration in the vertical direction of the vehicle body Detecting means Qη...Means for detecting vehicle speed θ~...Controlling means a9...Front wheel side pressure measurement chamber (A)...Rear wheel side pressure measurement chamber...
Compressed air pump (231...pressure accumulator CI'41
(2ω...3 position switching valve Q6) @ [Yes] Qto rotary yoke/to (31)...Front wheel load calculation circuit
02... Rear wheel load calculation circuit (c) C341... memory (c)... trigger circuit (g)...
Center of gravity position calculation circuit 371...Cornering force resultant action position calculation circuit ■...Static margin setting circuit G/turning ability setting circuit (vertical position)...Cornering power calculation circuit (
41)...Tire air pressure calculation circuit (42...Air pressure correction circuit (4144) (45X4e...Circuit for calculating the square root of the mean square) (4η...Circuit for calculating the front wheel side average value...Rear wheel Circuit to calculate side average value (4 springs/
... Comparator 5H2) ... Subtractor 53) e5
4)...Dead band setting circuit 551□□□57)se...
・Judgment circuit 6 Sakaki [F]■6I2...Sign discrimination circuit line...Alarm device (64)...Cornering power detection circuit 651 (66)...Alarm discrimination circuit (67)
1... Discrimination circuit patent applicant Nissan Motor Co., Ltd. agent Patent attorney Yu our army - Part 2 Figure 2

Claims (1)

[Claims] +11 In a vehicle equipped with pneumatic tires, a means for detecting the air pressure of the tire, a means for detecting the load applied to the tire, and a means for obtaining the required cornering power from the tire based on these. A tire pressure control device for a vehicle, comprising: a control means for controlling tire pressure. (2) In a vehicle equipped with pneumatic tires, a means for detecting the tire air pressure, a means for detecting the load on the tires, and based on these, detecting the load distribution of each wheel and making the static margin positive. A tire pressure control device for a vehicle, comprising: control means for controlling tire air pressure so that cornering power is obtained in the tire. (3) In a vehicle equipped with pneumatic tires, a means for detecting the tire air pressure, a means for detecting the load applied to the tire, a means for detecting the vibration level when the vehicle is running, and a means for detecting the tire air pressure based on these. A tire pressure control device for a vehicle, comprising: a control means for controlling; (4) The means for detecting the vibration level when the vehicle is running,
The tire pressure control device for a vehicle according to claim 3, wherein the vibration level is detected by measuring the root mean square value of the vibration acceleration in the vertical direction of the vehicle body. (5) In a vehicle equipped with pneumatic tires, a means for detecting the tire air pressure, a means for detecting the load on the tire, a means for detecting the vehicle speed, and a control means for controlling the tire air pressure based on these. A tire pressure control device for a vehicle, comprising: