JP2005271751A - Vehicle suspension system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the neutral hydraulic pressure (hydraulic pressure when the vehicle is stopped on a flat road) in a suspension hydraulic cylinder when the load weight of the vehicle increases from the standard state and the vehicle weight increases. To suppress it.
A suspension device for a vehicle includes suspension hydraulic cylinders 11 to 14 mounted together with a suspension main spring corresponding to each wheel, and an oil chamber Ro of the suspension hydraulic cylinders 11 to 14 via an oil passage. A behavior control unit (bouncing controller 20 or the like) connected to control the oil pressure in the oil chamber Ro is provided, and the behavior of the suspension hydraulic cylinders 11 to 14 is controlled by the behavior control unit, so that the behavior of the vehicle body is controlled. Be controlled. The single acting hydraulic cylinders 51 to 54 and the suspension auxiliary springs 61 to 64 are connected in series and are arranged in parallel to the suspension hydraulic cylinders 11 to 14. The oil chamber R1 of the single acting hydraulic cylinders 51 to 54 is connected to the oil chamber Ro of the suspension hydraulic cylinders 11 to 14 via an oil passage.
[Selection] Figure 1

Description

  The present invention relates to a vehicle suspension apparatus, and more particularly to a vehicle suspension apparatus configured to control the behavior of a vehicle body (bouncing, rolling, pitching, etc.) by controlling the operation of a suspension hydraulic cylinder. .

This type of vehicle suspension device is disclosed in, for example, Patent Document 1 below, and includes a suspension hydraulic cylinder mounted with a suspension main spring corresponding to each wheel, and an oil chamber of the suspension hydraulic cylinder. A behavior control unit that is connected via an oil passage and controls the hydraulic pressure of the oil chamber is provided, and the behavior of the vehicle body is controlled by controlling the operation of the suspension hydraulic cylinder by the behavior control unit. It is configured as follows.
JP 2003-146043 A

  In the vehicle suspension device described in Patent Document 1 described above, the behavior of the oil hydraulic chamber in the suspension hydraulic cylinder is controlled by the behavior control means, whereby the operation of the suspension hydraulic cylinder is controlled and the behavior of the vehicle body is controlled. Is controlled. By the way, the oil pressure in the oil chamber in the suspension hydraulic cylinder of Patent Document 1 described above changes in accordance with the vehicle weight. When the load weight increases and the vehicle weight increases, Compared to the case where the vehicle is stopped and the vehicle height and load weight are both in the standard state, the neutral oil pressure in the oil chamber in the suspension hydraulic cylinder (the oil pressure when the vehicle is stopped on a flat road) increases. As a result, optimal control characteristics may not be achieved.

  The present invention has been made to cope with the above-described problems, and includes a suspension hydraulic cylinder mounted with a suspension main spring corresponding to each wheel, and an oil passage in an oil chamber of the suspension hydraulic cylinder. And a behavior control means for controlling the hydraulic pressure of the oil chamber connected through the hydraulic cylinder, and the behavior of the vehicle body is controlled by controlling the operation of the suspension hydraulic cylinder by the behavior control means. In the vehicle suspension apparatus described above, a single-acting hydraulic cylinder and a suspension secondary spring are connected in series and arranged in parallel with the suspension main spring and the suspension hydraulic cylinder, and the single-acting hydraulic cylinder The oil chamber is connected to the oil chamber of the suspension hydraulic cylinder through an oil passage. In this case, it is preferable that the set load of the suspension auxiliary spring is substantially zero when the vehicle is stopped and the vehicle height and the loaded weight are both in the standard state.

  In this vehicle suspension system, when the load weight increases compared to the standard state, the neutral oil pressure of the oil chamber in the suspension hydraulic cylinder increases and changes, but this neutral oil pressure is applied to the oil chamber of the single acting hydraulic cylinder. The set load of the auxiliary spring for suspension is increased. For this reason, in this case, the shared load of the suspension auxiliary spring (the load that shares and bears the vehicle weight) increases, and the increase in the neutral hydraulic pressure is suppressed. Therefore, the deterioration of the control characteristics due to the increase in the neutral hydraulic pressure is suppressed, and the control characteristics can be improved.

  The present invention also provides a suspension hydraulic cylinder mounted with a suspension main spring corresponding to each wheel, and is connected to the oil chamber of the suspension hydraulic cylinder via an oil passage to control the oil pressure of the oil chamber. In the suspension device for a vehicle, wherein the behavior of the vehicle body is controlled by controlling the operation of the suspension hydraulic cylinder by the behavior control means. And the suspension hydraulic cylinder are arranged in parallel, a single-action hydraulic cylinder is connected in series to the suspension main spring, and the oil chamber of the single-action hydraulic cylinder is changed to the oil chamber of the suspension hydraulic cylinder. It is characterized by being connected through an oil passage. In this case, it is preferable that the output of the single-acting hydraulic cylinder is substantially zero when the vehicle is stopped and both the vehicle height and the loaded weight are in the standard state.

  In this vehicle suspension system, when the load weight increases compared to the standard state, the neutral oil pressure of the oil chamber in the suspension hydraulic cylinder increases and changes, but this neutral oil pressure is applied to the oil chamber of the single acting hydraulic cylinder. The set load of the suspension main spring is increased. For this reason, in this case, the set load of the suspension main spring is increased as compared with the standard state, and the increase in the neutral hydraulic pressure is suppressed. Therefore, the deterioration of the control characteristics due to the increase in the neutral hydraulic pressure is suppressed, and the control characteristics can be improved.

  Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 schematically show an embodiment in which a vehicle suspension device according to the present invention is applied to a four-wheeled vehicle. In this suspension device, each suspension hydraulic cylinder 11, 12, 13, 14 is provided. It is connected to the bouncing controller 20, the rolling controller 30, and the pitching controller 40 via pipes (oil passages) P1, P2, P3, and P4.

  Each of the suspension hydraulic cylinders 11, 12, 13, and 14 is mounted corresponding to the front, rear, left, and right wheels (not shown), and has a single input / output port 11a, 12a, 13a, and 14a. doing. The suspension hydraulic cylinders 11, 12, 13, and 14 include suspension main springs 15, 16, 17, and 18, single-action hydraulic cylinders 51, 52, 53, and 54, and suspension secondary springs 61 and 62, respectively. , 63, 64 and the unsprung member 70 and the unsprung member 80.

  Each suspension main spring 15, 16, 17, 18 is arranged in parallel to each suspension hydraulic cylinder 11, 12, 13, 14, and the vehicle is stopped on a flat road and When both the loaded weights are in the standard state, they are interposed between the sprung member 70 and the unsprung member 80 with a predetermined set load applied. Each single acting hydraulic cylinder 51, 52, 53, 54 and each suspension auxiliary spring 61, 62, 63, 64 are connected in series, and each suspension hydraulic cylinder 11, 12, 13, 14 and each suspension is suspended. The main springs 15, 16, 17 and 18 are arranged in parallel.

  As shown in FIG. 2, each single-acting hydraulic cylinder 51, 52, 53, 54 has a head chamber (lower chamber) as an oil chamber R1 and a rod chamber (upper chamber) as an air chamber R2. The unsprung member 80 is assembled at the side end. The oil chambers R1 of the single acting hydraulic cylinders 51, 52, 53, 54 are connected to the oil chambers Ro on the head side of the suspension hydraulic cylinders 11, 12, 13, 14, respectively by pipes (oil passages) P5, P6. They are connected via P7 and P8, respectively.

  Each suspension secondary spring 61, 62, 63, 64 is interposed between the piston rod upper end of each single-acting hydraulic cylinder 51, 52, 53, 54 and the sprung member 70, and the vehicle stops on a flat road. When the vehicle height and the loaded weight are both in the standard state, the set load is set to be substantially zero.

  The bouncing controller 20 is behavior control means for controlling the operation of each suspension hydraulic cylinder 11, 12, 13, 14 in a state where bouncing, which is one of the behaviors of the vehicle body, occurs. Bouncing control cylinders 21, 22, 23, 24 connected to input / output ports 11a, 12a, 13a, 14a of 11, 12, 13, 14 via pipes P1, P2, P3, P4, respectively. The bouncing control cylinders 21, 22, 23, and 24 include pistons 21a, 22a, 23a, and 24a having substantially the same pressure receiving area.

  The bouncing control cylinders 21 and 24 are connected to the suspension hydraulic cylinders 11 and 14 located diagonally (front left and rear right), and their respective operations are in phase (pistons 21a and 24a and the diagonal direction hydraulic control cylinder 20A. In the diagonal hydraulic control cylinder 20A, pistons 21a and 24a of both bouncing control cylinders 21 and 24 are connected and integrated.

  On the other hand, the bouncing control cylinders 22 and 23 are connected to both suspension hydraulic cylinders 12 and 13 located diagonally (front right and rear left), and are connected so that their operations are in phase. A diagonal hydraulic control cylinder 20B is configured. In the diagonal hydraulic control cylinder 20B, pistons 22a and 23a of both bouncing control cylinders 22 and 23 are connected and integrated.

  Each of the diagonal hydraulic control cylinders 20A and 20B has a symmetrical shape, is opposed to each other, and includes an accumulator 25 (which can be implemented by a gas type or a spring type) that also functions as a spring element. The control cylinders 20A and 20B are connected by connecting means 20C capable of controlling the operation of the control cylinders 20A and 20B. The connecting means 20C has a liquid seal connection structure using hydraulic oil as a medium, and includes a hydraulic chamber 27 communicating with the hydraulic chamber 25a of the accumulator 25 via a variable throttle 26 that functions as a damping element that suppresses vibration of the spring element. I have.

  The rolling controller 30 is behavior control means for controlling the operation of each suspension hydraulic cylinder 11, 12, 13, 14 in a state where rolling, which is one of the behaviors of the vehicle body, occurs. Rolling control cylinders 31, 32, 33, 34 connected to input / output ports 11a, 12a, 13a, 14a of 11, 12, 13, 14 via pipes P1, P2, P3, P4, respectively. The rolling control cylinders 31, 32, 33, and 34 are provided with pistons 31a, 32a, 33a, and 34a having substantially the same pressure receiving area.

  Each rolling control cylinder 31, 34 is connected to both suspension hydraulic cylinders 11, 14 located diagonally (front left and right rear), and each operation thereof is in reverse phase (piston 31a associated with increase / decrease in hydraulic pressure). , 34a are reversed so that the left and right rolling control cylinder 30A is configured. In the left and right pair rolling control cylinder 30A, the pistons 31a and 34a of both the rolling control cylinders 31 and 34 are integrated and shared.

  On the other hand, the rolling control cylinders 32 and 33 are connected to both suspension hydraulic cylinders 12 and 13 located diagonally (front right and rear left), and are connected so that their operations are in opposite phases. The left and right pair rolling control cylinder 30B is configured. In the left and right pair rolling control cylinder 30B, pistons 32a and 33a of both rolling control cylinders 32 and 33 are integrated and shared.

  The left and right paired rolling control cylinders 30A and 30B are in phase (for example, when both the hydraulic cylinders 11 and 13 on the left side are raised, both pistons 31a, 34a and 32a, 33a are pushed to the right in the figure. Each piston 31a, 34a and 32a, 33a are connected via a connecting rod 35. The connecting rod 35 extends outside the cylinder, and has one end of a coil spring 36 that functions as a spring element at its extended end and one end of a shock absorber 37 that functions as a damping element that controls vibration of the spring element. The operation (axial movement) is controlled by a coil spring 36 and a shock absorber 37.

  The pitching controller 40 is behavior control means for controlling the operation of the suspension hydraulic cylinders 11, 12, 13, and 14 in a state where pitching, which is one of the behaviors of the vehicle body, is generated. Pitching control cylinders 41, 42, 43, 44 connected to the input / output ports 11a, 12a, 13a, 14a of 11, 12, 13, 14 via pipes P1, P2, P3, P4, respectively, The pitching control cylinders 41, 42, 43, 44 are provided with pistons 41a, 42a, 43a, 44a having substantially the same pressure receiving area.

  The pitching control cylinders 41 and 44 are connected to both suspension hydraulic cylinders 11 and 14 located diagonally (front left and rear right), and are connected so that their operations are in opposite phases. An anti-pitching control cylinder 40A is configured. In the front / rear pair pitching control cylinder 40A, the pistons 41a, 44a of both the pitching control cylinders 41, 44 are integrated and shared.

  On the other hand, the pitching control cylinders 42 and 43 are connected to both suspension hydraulic cylinders 12 and 13 located diagonally (front right and rear left), and are connected so that their operations are in opposite phases. The front / rear pair pitching control cylinder 40B is configured. In the front / rear pair pitching control cylinder 40B, the pistons 42a and 43a of both the pitching control cylinders 42 and 43 are integrated and shared.

  Each of the front and rear pair pitching control cylinders 40A and 40B has a reverse phase (for example, when the hydraulic pressure of the front suspension hydraulic cylinders 11 and 12 is increased, both pistons 41a and 44a and 42a and 43a are both on the right side of the figure. The pistons 41 a, 44 a and 42 a, 43 a are connected via a connecting rod 45. The connecting rod 45 extends out of the cylinder, and has one end of a coil spring 46 that functions as a spring element at the extended end portion and one end of a shock absorber 47 that functions as a damping element that controls vibration of the spring element. The operation (axial movement) is controlled by a coil spring 46 and a shock absorber 47.

  As shown in FIG. 2, the vehicle suspension apparatus of this embodiment configured as described above includes the single-acting hydraulic cylinders 51, 52, 53, 54 and the suspension auxiliary springs 61, 62, 63, 64. Except for the configuration in which the suspension hydraulic cylinders 11, 12, 13, 14 and the suspension main springs 15, 16, 17, 18 are arranged in parallel in a state of being connected in series. The configuration of the embodiment shown in FIGS. 1 to 5 of Japanese Patent Application Laid-Open No. 2003-146043 is the same as that of the embodiment shown in FIGS. 1 to 5, when bouncing the vehicle, rolling the vehicle accompanying turning of the vehicle, pitching the vehicle, The effect similar to that of the embodiment shown in FIGS. 1 to 5 of the above publication can be obtained at the time of twist input.

  Further, in the vehicle suspension apparatus of this embodiment, each single acting hydraulic cylinder 51, 52, 53, 54 and each suspension auxiliary spring 61, 62, 63, 64 are connected in series. Since the hydraulic cylinders 11, 12, 13, 14 and the suspension main springs 15, 16, 17, 18 are arranged in parallel to each other, when the load weight increases compared to the standard state, each suspension Although the neutral oil pressure of the oil chamber Ro in the hydraulic cylinders 11, 12, 13, and 14 (the oil pressure in a state where the vehicle is stopped on a flat road) increases and changes, It is given to the oil chamber R1 of 52, 53, 54 and the set load of each suspension auxiliary spring 61, 62, 63, 64 is increased. For this reason, in this case, the shared load of the suspension auxiliary springs 61, 62, 63, 64 is increased, and the increase in the neutral hydraulic pressure is suppressed. Therefore, the deterioration of the control characteristics due to the increase in the neutral hydraulic pressure is suppressed, and the control characteristics can be improved.

  In the vehicle suspension device of this embodiment, the connecting means 20C for connecting the diagonal hydraulic control cylinders 20A and 20B in the bouncing controller 20 includes the accumulator 25 and the variable throttle 26, and the hydraulic oil is used as a medium. Therefore, the hydraulic oil in the hydraulic chamber 27 (or the hydraulic chamber 25a of the accumulator 25) communicating with the accumulator 25 via the variable throttle 26 is taken in and out in accordance with, for example, the vehicle weight (body load). By adopting a vehicle height adjusting hydraulic circuit (not shown), the vehicle height can be adjusted while maintaining the posture of the vehicle body.

  In the above embodiment, the present invention is applied to a vehicle suspension apparatus in which the suspension hydraulic cylinders 11, 12, 13, and 14 are arranged in parallel to the suspension main springs 15, 16, 17, and 18, respectively. Although implemented, each suspension hydraulic cylinder 11, 12, 13, 14 is similarly applied to a vehicle suspension apparatus in which the suspension main springs 15, 16, 17, 18 are arranged in series. It is possible to carry out by carrying out or changing suitably.

  Moreover, in the said embodiment, when each single acting hydraulic cylinder 51,52,53,54 and each suspension subspring 61,62,63,64 are connected in series, each single acting hydraulic cylinder 51,52. , 53, 54 are arranged on the upper side and the suspension auxiliary springs 61, 62, 63, 64 are arranged on the lower side, but each single-acting hydraulic cylinder 51, 52, 53, 54 is It is also possible to arrange and implement the suspension auxiliary springs 61, 62, 63, 64 arranged at the lower side.

  In the above embodiment, as shown in FIG. 2, each single-acting hydraulic cylinder 51, 52, 53, 54 and each suspension secondary spring 61, 62, 63, 64 are connected in series. The suspension hydraulic cylinders 11, 12, 13, and 14 and the suspension main springs 15, 16, 17, and 18 are arranged in parallel with each other, as shown in FIG. The single-acting hydraulic cylinders 51, 52, 53, 54 are connected in series to the suspension main springs 15, 16, 17, 18 arranged in parallel to the suspension hydraulic cylinders 11, 12, 13, 14, respectively. It can also be configured and implemented. In this embodiment, the auxiliary springs 61, 62, 63, 64 for suspension are not necessary.

  In the embodiment shown in FIG. 3, when the vehicle is stopped on a flat road and the vehicle height and the loaded weight are both in the standard state, the output of each single-acting hydraulic cylinder 51, 52, 53, 54 ( It is also possible to set the suspension main springs 15, 16, 17, 18 to have substantially zero set force.

  In the vehicle suspension apparatus of the embodiment shown in FIG. 3, when the loaded weight increases as compared with the standard state, the neutral oil pressure of the oil chamber Ro in each suspension hydraulic cylinder 11, 12, 13, 14 increases and changes. However, this neutral hydraulic pressure is applied to the oil chamber R1 of each single-acting hydraulic cylinder 51, 52, 53, 54 to increase the set load of each suspension main spring 15, 16, 17, 18. For this reason, in this case, the set load of each suspension main spring 15, 16, 17, 18 is increased as compared with the standard state, and the increase in the neutral hydraulic pressure is suppressed. Therefore, the deterioration of the control characteristics due to the increase in the neutral hydraulic pressure is suppressed, and the control characteristics can be improved.

  In the above-described embodiment, the vehicle suspension apparatus includes the bouncing controller 20, the rolling controller 30, and the pitching controller 40 (three behavior control means). However, the vehicle suspension apparatus is a bouncing controller. 20, a configuration including at least one of the rolling controller 30 and the pitching controller 40 is also possible.

1 is a hydraulic circuit diagram schematically showing an embodiment of a vehicle suspension apparatus according to the present invention. It is a principal part enlarged view of the suspension apparatus for vehicles shown in FIG. FIG. 5 is an enlarged view of a main part schematically showing another embodiment of a vehicle suspension device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12, 13, 14 ... Suspension hydraulic cylinder, 15, 16, 17, 18 ... Main spring for suspension, 20 ... Bouncing controller, 30 ... Rolling controller, 40 ... Pitching controller, 51, 52, 53, 54 ... Single acting hydraulic cylinders 61, 62, 63, 64 ... Suspension auxiliary springs, P1, to P8 ... Piping (oil path), Ro ... Suspension hydraulic cylinder oil chamber, R1 ... Single acting hydraulic cylinder oil chamber , R2 ... Single-acting hydraulic cylinder air chamber

Claims (4)

  A suspension hydraulic cylinder mounted with a suspension main spring corresponding to each wheel, and a behavior control means connected to the oil chamber of the suspension hydraulic cylinder via an oil passage to control the oil pressure of the oil chamber. In the vehicle suspension apparatus configured to control the behavior of the vehicle body by controlling the operation of the suspension hydraulic cylinder by the behavior control means, a single-acting hydraulic cylinder and a suspension secondary spring are provided. It is connected in series and arranged in parallel with the suspension main spring and the suspension hydraulic cylinder, and the oil chamber of the single acting hydraulic cylinder is connected to the oil chamber of the suspension hydraulic cylinder via an oil passage. A suspension system for a vehicle characterized by being connected.   2. The suspension device for a vehicle according to claim 1, wherein when the vehicle is stopped and the vehicle height and the loaded weight are both in a standard state, the set load of the suspension auxiliary spring is substantially zero. Vehicle suspension device.   A suspension hydraulic cylinder mounted with a suspension main spring corresponding to each wheel, and a behavior control means connected to the oil chamber of the suspension hydraulic cylinder via an oil passage to control the oil pressure of the oil chamber. The suspension main spring and the suspension hydraulic cylinder are configured so that the behavior of the vehicle body is controlled by controlling the operation of the suspension hydraulic cylinder by the behavior control means. Are arranged in parallel, and a single acting hydraulic cylinder is connected in series to the suspension main spring, and the oil chamber of the single acting hydraulic cylinder is connected to the oil chamber of the suspension hydraulic cylinder via an oil passage. A suspension device for a vehicle characterized by the above. 4. The vehicle suspension device according to claim 3, wherein the output of the single-acting hydraulic cylinder is substantially zero when the vehicle is stopped and both the vehicle height and the loaded weight are in a standard state. Suspension device.