JP2007038791A - Suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension device capable of reducing the capacity of a motor constituting a pump required for flowing a hydraulic fluid, and enabling adjustment of the car height. <P>SOLUTION: This suspension device is formed by connecting an axle member 1 for rotatably supporting a wheel W to a vehicle body S through a shock absorber 2 and a spring 3. A first liquid chamber 4 is interposed in series with the spring 3 between the axle member 2 and the vehicle body S, and a second liquid chamber 7 is communicated with the first liquid chamber 4 through a passage 5, and forms a part of an accumulator 6. The passage 5 is provided with a pump 8 for feeding liquid in both directions. The accumulator 6 is provided with a temperature adjusting means 13 for adjusting the temperature of the accumulator 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a suspension device capable of adjusting a vehicle height.

  As a suspension apparatus capable of adjusting the vehicle height, conventionally, as disclosed in Patent Document 1, as shown in FIG. 5 or FIG. 6, a piston 103 is joined to a lower end portion of a cylinder housing 102 of a shock absorber 101, and the piston 103 is liquid-tightly and slidably fitted in the additional cylinder housing 104, and an upper liquid chamber 105 and a lower liquid chamber 106, which are partitioned above and below the piston 103 in the additional cylinder housing 104, are pumped. There has been proposed an apparatus in which vehicle height adjustment is performed by allowing fluid to flow between the upper liquid chamber 105 and the lower liquid chamber 106 in fluid-tight communication with each other via 107. In FIG. 5, it is the structure which makes a hydraulic fluid flow between the upper side liquid chamber 105 and the lower side liquid chamber 106 using the switching valve 108, and in FIG. As described above, the hydraulic fluid is allowed to flow between the upper liquid chamber 105 and the lower liquid chamber 106. In any configuration, the volume of the hydraulic fluid in the upper liquid chamber 105 accompanying the vertical movement of the piston 103 is A reservoir 109 for absorbing a volume difference from the volume of the hydraulic fluid in the lower liquid chamber 106 is provided, and the hydraulic fluid in the reservoir 109 communicates with atmospheric pressure.

5 and 6, when the work amount of the pump 107 is considered, the work amount is represented by the product P × Q of the differential pressure P before and after the pump 107 and the flow rate Q discharged from the pump. In any of these configurations, since the hydraulic fluid in the reservoir 109 communicates with the atmospheric pressure, it operates up to the pressure required to move the piston 103 up and down, that is, the pressure that can support the minimum vehicle weight. There is a problem that the pressure of the liquid needs to be increased, and the work amount of the pump 107 is increased due to the large differential pressure P, and the capacity of the motor constituting the pump 107 is increased.
JP-A-5-162525

  An object of the present invention is to solve the above-described problems of the prior art, and the object of the present invention is to reduce the capacity of a motor that constitutes a pump necessary for flowing a working fluid. An object of the present invention is to provide a suspension device capable of adjusting the vehicle height that can be made small.

The suspension device according to claim 1 is a suspension device in which an axle member that rotatably supports a wheel is connected to a vehicle body via a shock absorber and a spring,
Between the axle member and the vehicle body, a first liquid chamber is interposed in series with the spring,
While communicating with the first liquid chamber via a flow path, a second liquid chamber forming a part of an accumulator is provided,
A pump capable of bidirectional liquid feeding is provided in the flow path,
The accumulator is provided with temperature adjusting means capable of adjusting the temperature of the accumulator.

  According to the suspension device of the first aspect, the second liquid chamber corresponding to the reservoir in the conventional configuration shown in FIGS. 5 and 6 is a liquid chamber that forms a part of the accumulator, and therefore is necessary to support the vehicle weight. Pressure can be pre-biased to the hydraulic fluid by the accumulator, which eliminates the need for boosting the hydraulic fluid from atmospheric pressure to the pressure required to support the vehicle weight, As well as the capacity of the motor constituting the pump can be reduced.

  In addition, in the suspension device according to the first aspect, by providing the accumulator with a temperature adjusting means capable of adjusting the temperature of the accumulator, the mass change of the vehicle and the temperature change of the accumulator (the mass increases or the temperature If it decreases, the balance stroke value becomes lower than the median value.If the mass decreases or the temperature rises, the balance stroke value becomes higher than the median value.) When the balance stroke value is higher than the median value by the temperature adjusting means, the temperature of the accumulator is lowered to contract the volume of the gas chamber in the accumulator, and the working fluid is transferred from the first liquid chamber to the second liquid chamber in the accumulator. Discharge, lower the balance stroke value, the balance stroke value is lower than the median In this case, the temperature of the accumulator is increased to expand the volume of the gas chamber in the accumulator, the working fluid is supplied from the second liquid chamber in the accumulator to the first liquid chamber, and the balance stroke value is increased. The balance stroke value of the liquid chamber can be adjusted to be a median value, thereby driving the pump and causing the working fluid to flow between the first liquid chamber and the second liquid chamber, When the ride comfort control of the vehicle is performed, it is possible to sufficiently ensure both the expansion side and contraction side strokes of the first liquid chamber.

  Further, in the suspension device according to claim 1, adjusting the vehicle height to an arbitrary height and maintaining the height means supplying and discharging the hydraulic fluid to and from the first liquid chamber by the temperature adjusting means. Compared to supplying and discharging hydraulic fluid to and from the first fluid chamber with a pump that can feed fluid in both directions, it eliminates the generation of torque under extremely low rotation of the motor and wastes energy. And the heat generation of the motor driving the pump can be suppressed.

Embodiments of the present invention will be described below in detail based on the drawings.
FIG. 1 and FIG. 2 are schematic views showing a main part of a suspension device according to an embodiment of the present invention.

As shown in FIG. 1 (a), a suspension apparatus according to an embodiment of the present invention includes an axle member 1 that rotatably supports a wheel W via a shock absorber 2 and a spring 3 that extend in the vertical direction. A suspension device connected to the vehicle body S,
A first liquid chamber 4 is interposed between the axle member 1 and the vehicle body S in series with the spring 3.
A second liquid chamber 7 that communicates with the first liquid chamber 4 via the flow path 5 and forms a part of the accumulator 6 is provided.
The flow path 5 is provided with a pump 8 capable of feeding liquid in both directions.
Further, although not shown here, the accumulator is provided with temperature adjusting means capable of adjusting the temperature of the accumulator. (Equivalent to claim 1)
Or it is good also as a structure which adjusts the balance stroke value with the said vehicle body S of the 1st liquid chamber 4 by adjusting the temperature of the accumulator 6. FIG. (Equivalent to claim 6)

  Here, the first liquid chamber 4 is provided on the axle member 1 side, which is a member on the wheel W side, and the accumulator 6 and the pump 8 are provided on the vehicle body S side. Moreover, in order to absorb the displacement by the stroke as a suspension apparatus, the flow path 5 is partially formed with the elastic member (for example, rubber hose).

Here, the first liquid chamber 4 is configured by fitting the additional cylinder housing 10 into the cylinder housing 9 of the shock absorber 2 in a liquid-tight manner, but the form of the first liquid chamber is not limited to this. In other words, it is sufficient if it is arranged in series with the spring 3 between the axle member 1 and the vehicle body S.
The form of the pump 8 is not particularly limited, but here, a gear type is used, and 11 indicates a motor constituting the pump 8.
Further, in the accumulator 6, a gas chamber 12 is provided that serves as an air spring that biases the pressure of the hydraulic fluid in the second liquid chamber 7.

  According to this, since the second liquid chamber 7 is a liquid chamber forming a part of the accumulator 6, the pressure required to support the vehicle weight is applied to the pressure in the second liquid chamber 7 by the gas chamber 12 of the accumulator 6. The hydraulic fluid can be energized in advance, which eliminates the need for boosting the hydraulic fluid from the atmospheric pressure to the pressure required to support the vehicle weight by the pump 8, and greatly reduces the work of the pump 8. In addition, the capacity of the motor 11 constituting the pump 8 can be reduced. That is, the motor 11 that constitutes the pump 8 may have a capacity sufficient to bear work for expanding and contracting the first liquid chamber 4.

  The accumulator is a pressure accumulator which converts pressure energy of hydraulic fluid (oil etc.) into pressure energy of gas (air, nitrogen gas etc.) and stores it. In general, according to an accumulator, a predetermined pressure (for example, 10 to 20 MPa) can be applied to the oil as the hydraulic fluid, and a response delay due to the compressibility of the oil is caused by a pressure of 1.0 MPa or less. Thus, the response delay due to the compressibility of oil can be eliminated as compared with the configuration using the conventional reservoir.

  Here, as shown in FIG. 1B, the balance stroke value of the first liquid chamber 4 becomes lower than the median value when the vehicle mass increases or the temperature of the accumulator 6 decreases. Further, as shown in FIG. 1C, the balance stroke value becomes higher than the median value when the vehicle mass becomes light or the temperature of the accumulator 7 rises.

  In the state shown in FIG. 1B, when the ride value of the vehicle body is controlled by controlling the stroke value of the first liquid chamber 4 by a control means (not shown) based on the vertical acceleration of the vehicle body S, the first liquid The stroke on the contraction side of the chamber 4 is insufficient, and sufficient and stable control cannot be performed. Further, in the state shown in FIG. 1 (c), when the ride value of the vehicle body is controlled by controlling the stroke value of the first liquid chamber 4 by a control means (not shown) based on the vertical acceleration of the vehicle body S, The stroke on the extension side of the one liquid chamber 4 is insufficient, and this also makes it impossible to perform sufficient and stable control.

  The specific control content of the ride comfort control of the vehicle body is, for example, when the vertical acceleration G of the vehicle body S is detected by a G sensor (not shown) provided on the vehicle body S and the vertical acceleration G is upward, The pump 8 is contracted so that the liquid chamber 4 is contracted at a speed proportional to the upward acceleration, and when the vertical acceleration G is downward, the first liquid chamber 4 is expanded at a speed proportional to the downward acceleration. It is conceivable to control the motor 11 constituting the electronic control unit ECU as a control means.

  In order to solve the shortage of the expansion side or contraction side stroke of the first liquid chamber 4 when the ride comfort control of the vehicle body is performed as described above, in the suspension device according to the present invention, as shown in FIG. 6 is provided with temperature adjusting means 13 capable of adjusting the temperature of the accumulator 6. The form of the accumulator 6 is not particularly limited, but here, a metal bellows type accumulator excellent in separation of gas and working fluid is used.

  As shown in FIG. 2, the temperature adjusting means 13 is provided in the gas chamber 12 of the accumulator 6, and receives a command from the electronic control unit ECU 14, and is provided on the outer peripheral side of the accumulator 6. A defined heating chamber 16, a supply passage 18 for supplying engine cooling water to the heating chamber 16 via a switching valve 17 so as to be shut off, and a discharge passage 19 for sending the cooling water from the heating chamber 16 back to the engine. The ECU 14 controls the switching valve 17 and the heat exchange fins 20 provided on the outer peripheral side of the heating chamber.

  If the temperature adjusting means 13 is only the heater 15 (corresponding to claim 2), the responsiveness of the temperature rise of the accumulator can be improved, but power is always consumed when the temperature rises, but the temperature adjusting means 13 If it is a waste heat utilization heating means such as the heating chamber 16 (corresponding to claim 3), the temperature of the accumulator can be increased without consuming energy such as electric power, but immediately after starting the engine. Because the engine coolant is not warm enough, the effect of temperature rise is diminished.

For this reason, here, the temperature adjusting means 13 is configured to use the heater 15 and the heating chamber 16 as the exhaust heat utilization heating means in combination. (Equivalent to Claim 4) Thereby, the heater 15 and the heating chamber 16 can be selected according to convenience, and each advantage mentioned above can be utilized to the maximum.
In addition, the ECU 14 functioning as the exhaust heat temperature detecting means constantly monitors the temperature of the cooling water as the exhaust heat temperature of the exhaust heat utilizing heating means by the engine coolant temperature sensor 21, and the temperature of the coolant is sufficiently high. Until the temperature rises, an on command is issued to the heater 15, the accumulator 6 is heated by the heater 15, and when the temperature of the cooling water becomes sufficiently high, an off command is issued to the heater 15 and the switching valve 17 is turned on. As opening, cooling water is supplied to the heating chamber 16 to heat the accumulator 6. (Equivalent to Claim 5) Thereby, switching of the heater 15 and the exhaust heat utilization heating means as the temperature control means 13 can be performed based on the exhaust heat temperature.
Here, in using exhaust heat, engine cooling water is used here, but it is also possible to use engine lubricating oil, exhaust gas, and the like.

  In order to cool the accumulator 6, when heated by the heater 15, the ECU 14 issues an off command to the heater 15, and when heated by the heating chamber 16, the switching valve 17 is closed and the cooling liquid heating chamber 16 is closed. Stop supplying to As a result, the heating is stopped and the heat in the accumulator 6 is dissipated mainly by the heat exchange fins 20 to cool the accumulator 6. The heat exchanging fins 20 are for enhancing the heat dissipation effect, and may be omitted.

  Note that the gas in the gas chamber of the accumulator 6 can be a low-boiling pressure medium such as an alternative chlorofluorocarbon, for example. In this case, the temperature of the pressure medium changes compared to using a normal pressure medium. Accordingly, a large volume change can be obtained by expansion due to the change from the liquid phase to the gas phase or contraction due to the reverse change, so that the expansion and contraction rate of the gas chamber can be increased. The line shown on the upper side of the heater 15 in FIG. 2 indicates the boundary between the liquid phase and the gas phase.

Hereinafter, the balance stroke adjusting operation according to this configuration will be described.
FIG. 3 is a schematic diagram showing an adjustment operation (raising) of the main part and the balance stroke value of the suspension device according to one embodiment of the present invention shown in FIG.
Hereinafter, the adjusting operation of the balancing stroke value by the temperature adjusting means will be described with reference to FIG.

  The balance stroke value of the first liquid chamber 4 becomes lower than the median value when the vehicle mass increases or the temperature of the accumulator 6 decreases. When the ride comfort control of the vehicle body is performed in this state, the stroke on the contraction side of the first liquid chamber 4 is insufficient, and it becomes impossible to control the ride comfort sufficiently and stably, so that the balance stroke value should be returned to the median value. Then, the hydraulic fluid is supplied to the first liquid chamber 4. Although not shown here, a detection means for detecting the balance stroke value is separately provided, and the balance stroke value is output to the electronic control unit ECU 14 as a signal. Based on the signal, the ECU 14 adjusts the balance stroke value. Control shall be performed.

  As described above, the ECU 14 constantly monitors the temperature of the cooling water detected by the engine cooling water temperature sensor 21, and issues an ON command to the heater 15 until the temperature of the cooling water becomes sufficiently high. When the accumulator 6 is heated by the heater 15 and the temperature of the cooling water is sufficiently high, an off command is issued to the heater 15, the switching valve 17 is opened, and the cooling water is supplied to the heating chamber 16, The accumulator 6 is heated.

  Thus, by heating the accumulator 6, the gas in the gas chamber 12 expands, and when the gas chamber 12 expands, the volume of the second liquid chamber 7 contracts, so that the hydraulic fluid is It is supplied from the two-liquid chamber 7 to the first liquid chamber 4, and the balance stroke value can be raised to adjust the balance stroke value to the median value.

FIG. 4 is a schematic diagram showing an adjustment operation (lowering) of the main part and the balance stroke value of the suspension device according to one embodiment of the present invention shown in FIG.
Hereinafter, the adjusting operation (lowering) of the balancing stroke value by the temperature adjusting means will be described with reference to FIG.

  The balance stroke value of the first liquid chamber 4 becomes higher than the median value when the vehicle mass is reduced or the temperature of the accumulator 6 is increased. When the ride comfort control of the vehicle body is performed in this state, the stroke on the extension side of the first liquid chamber 4 is insufficient, and it becomes impossible to control the ride comfort sufficiently and stably, so that the balance stroke value should be returned to the median value. The hydraulic fluid is discharged from the first liquid chamber 4.

  As described above, in order to cool the accumulator 6, when the heater 15 is heating, the ECU 14 issues an OFF command to the heater 15, and when the heater 15 is heated, the switching valve 17 is closed and the cooling is performed. Supply of the liquid to the heating chamber 16 is stopped. As a result, the heating is stopped and the heat in the accumulator 6 is dissipated by the heat exchange fins 20 to cool the accumulator 6.

  When the accumulator 6 is cooled, the gas in the gas chamber 12 contracts, and the gas chamber 12 contracts, whereby the volume of the second liquid chamber 7 expands. It is discharged to the second liquid chamber 7 and the balance stroke value can be lowered to adjust the balance stroke value to the median value.

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible.

  The present invention is effective when applied to a suspension device capable of adjusting the vehicle height.

It is a mimetic diagram showing the important section of a suspension device which is one embodiment of the present invention. It is a mimetic diagram showing the important section of a suspension device which is one embodiment of the present invention. It is a schematic diagram which shows the adjustment operation | movement (raising) of the principal part and balance stroke value of the suspension apparatus which is one Embodiment of this invention shown in FIG. It is a schematic diagram which shows the principal part of the suspension apparatus which is one Embodiment of this invention shown in FIG. 2, and the adjustment operation (down) of a balance stroke value. It is a schematic diagram which shows the principal part of the conventional suspension apparatus. It is a schematic diagram which shows the principal part of the conventional suspension apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axle member 2 Shock absorber 3 Spring 4 1st liquid chamber 5 Flow path 6 Accumulator 7 2nd liquid chamber 8 Pump 9 Cylinder housing 10 Additional cylinder housing 11 Motor 12 Gas chamber 13 Temperature control means 14 Electronic control unit (ECU)
15 Heater 16 Heating chamber 17 Switching valve 18 Supply passage 19 Discharge passage 20 Heat exchange fin 21 Cooling water temperature sensor

Claims (6)

A suspension device, in which an axle member that rotatably supports a wheel is connected to a vehicle body via a shock absorber and a spring,
Between the axle member and the vehicle body, a first liquid chamber is interposed in series with the spring,
While communicating with the first liquid chamber via a flow path, a second liquid chamber forming a part of an accumulator is provided,
A pump capable of bidirectional liquid feeding is provided in the flow path,
A suspension device characterized in that the accumulator is provided with temperature adjusting means capable of adjusting the temperature of the accumulator.   The suspension device according to claim 1, wherein the temperature adjusting means is a heater.   The suspension device according to claim 1, wherein the temperature adjusting means is exhaust heat utilization heating means.   The suspension device according to claim 1, wherein the temperature adjusting unit is configured by combining a heater and the exhaust heat utilization heating unit.   The exhaust heat temperature detecting means for detecting the exhaust heat temperature used in the exhaust heat utilization heating means is provided, and the temperature adjusting means is based on the exhaust heat temperature detected by the exhaust heat temperature detection means. The suspension device according to claim 4, wherein the temperature of the accumulator is adjusted by switching between a heater and the exhaust heat utilization heating means. A suspension device, in which an axle member that rotatably supports a wheel is connected to a vehicle body via a shock absorber and a spring,
Between the axle member and the vehicle body, a first liquid chamber is interposed in series with the spring,
While communicating with the first liquid chamber via a flow path, a second liquid chamber forming a part of an accumulator is provided,
A pump capable of bidirectional liquid feeding is provided in the flow path,
A suspension device, wherein a balance stroke value of the first liquid chamber with the vehicle body is adjusted by adjusting a temperature of the accumulator.

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