Vehicle with force-controlled shock absorber (2-pipe shock absorber)

Abstract

The invention relates to a shock absorber with a housing, an inner pipe arranged in the housing, a piston rod, a piston which is arranged at that end of the piston rod, and which piston divides the interior of the inner pipe into a lower chamber and an upper chamber, a first valve arrangement which is arranged on the piston, and a third valve arrangement which is arranged at the lower end of the inner pipe and by means of which the working medium which is held in the interior of the housing, serving as a tank, can flow out of the interior of the housing, only into the lower chamber when the piston moves in the inner pipe. The shock absorber is distinguished by the fact that a hydraulic pump drive is arranged between a first connection element of the lower chamber of the inner pipe and a second connection element at the upper chamber of the inner pipe.

Claims

1. A shock absorber comprising: a) a housing; b) an inner pipe arranged in the housing; c) a piston rod that plunges into the inner pipe; d) a piston arranged on the end of the piston rod that plunges into the inner pipe, which piston divides the inside of the inner pipe into a lower chamber and an upper chamber; e) a first valve arrangement arranged on the piston, by means of which a working medium received in the inner pipe can flow out of the lower chamber into the upper chamber and vice versa when the piston is moved in the inner pipe; f) a second valve arrangement arranged at the upper end of the inner pipe, by means of which, when the piston is moved in the inner pipe, the working medium received in the inner pipe can flow out of the upper chamber only into the inside of the housing serving as a tank for the working medium; and g) a third valve arrangement arranged at the lower end of the inner pipe, by means of which the working medium received in the inside of the housing serving as a tank can flow out of the inside of the housing serving as a tank only into the lower chamber when the piston is moved in the inner pipe, wherein a hydraulic pump drive is arranged between a first connection element of the lower chamber of the inner pipe and a second connection element at the upper chamber of the inner pipe, and wherein a leakage pipe for the working medium is provided between the housing serving as a tank for the working medium and the hydraulic pump drive.

2. The shock absorber according to claim 1, wherein the hydraulic pump drive is connected to the lower and the upper connection element by means of pressure lines.

3. The shock absorber according to claim 1, wherein a valve arrangement, in particular a solenoid valve or a proportional flow control valve, is provided for controlling the flow resistance of the working medium in the first valve arrangement, said valve arrangement being arranged between a pressure line connected at the lower connection element and a pressure line connected at the upper connection element.

4. The shock absorber according to claim 1, wherein the hydraulic pump drive comprises a controllable pump and a motor for the pump.

5. The shock absorber according to claim 2, wherein a feed line for the working medium is provided between the housing serving as a tank for the working medium and at least one of the lower pressure line and the upper pressure line.

6. The shock absorber according to claim 5, wherein a non-return valve or a control valve respectively is arranged between the feed line and at least one of the lower pressure line and the upper pressure line.

7. The shock absorber according to claim 1, wherein a rising pipe is arranged at the upper end of the inner pipe, which rising pipe protrudes into the working medium received in the housing and by means of which working medium can be transferred from the housing serving as a tank into the upper chamber of the inner pipe.

8. The shock absorber according to claim 1, wherein the hydraulic pump drive comprises a controllable pump and a motor for the pump.

9. A shock absorber comprising: a) a housing; b) an inner pipe arranged in the housing; c) a piston rod that plunges into the inner pipe; d) a piston arranged on the end of the piston rod that plunges into the inner pipe, which piston divides the inside of the inner pipe into a lower chamber and an upper chamber; e) a first valve arrangement arranged on the piston, by means of which a working medium received in the inner pipe can flow out of the lower chamber into the upper chamber and vice versa when the piston is moved in the inner pipe; f) a second valve arrangement arranged at the upper end of the inner pipe, by means of which, when the piston is moved in the inner pipe, the working medium received in the inner pipe can flow out of the upper chamber only into the inside of the housing serving as a tank for the working medium; and g) a third valve arrangement arranged at the lower end of the inner pipe, by means of which the working medium received in the inside of the housing serving as a tank can flow out of the inside of the housing serving as a tank only into the lower chamber when the piston is moved in the inner pipe, wherein a hydraulic pump drive is arranged between a first connection element of the lower chamber of the inner pipe and a second connection element at the upper chamber of the inner pipe, wherein the hydraulic pump drive is connected to the lower and the upper connection element by means of pressure lines, and wherein a feed line for the working medium is provided between the housing serving as a tank for the working medium and at least one of the lower pressure line and the upper pressure line.

10. The shock absorber according to claim 9, wherein a non-return valve or a control valve respectively is arranged between the feed line and at least one of the lower pressure line and the upper pressure line.

11. The shock absorber according to claim 9, wherein a valve arrangement, in particular a solenoid valve or a proportional flow control valve, is provided for controlling the flow resistance of the working medium in the first valve arrangement, said valve arrangement being arranged between a pressure line connected at the lower connection element and a pressure line connected at the upper connection element.

12. A shock absorber comprising: a) a housing; b) an inner pipe arranged in the housing; c) a piston rod that plunges into the inner pipe; d) a piston arranged on the end of the piston rod that plunges into the inner pipe, which piston divides the inside of the inner pipe into a lower chamber and an upper chamber; e) a first valve arrangement arranged on the piston, by means of which a working medium received in the inner pipe can flow out of the lower chamber into the upper chamber and vice versa when the piston is moved in the inner pipe; f) a second valve arrangement arranged at the upper end of the inner pipe, by means of which, when the piston is moved in the inner pipe, the working medium received in the inner pipe can flow out of the upper chamber only into the inside of the housing serving as a tank for the working medium; g) a third valve arrangement arranged at the lower end of the inner pipe, by means of which the working medium received in the inside of the housing serving as a tank can flow out of the inside of the housing serving as a tank only into the lower chamber when the piston is moved in the inner pipe, wherein a hydraulic pump drive is arranged between a first connection element of the lower chamber of the inner pipe and a second connection element at the upper chamber of the inner pipe, wherein a rising pipe is arranged at the upper end of the inner pipe, which rising pipe protrudes into the working medium received in the housing and by means of which working medium can be transferred from the housing serving as a tank into the upper chamber of the inner pipe.

13. The shock absorber according to claim 12, wherein the hydraulic pump drive is connected to the lower and the upper connection element by means of pressure lines.

14. The shock absorber according to claim 13, wherein a feed line for the working medium is provided between the housing serving as a tank for the working medium and at least one of the lower pressure line and the upper pressure line.

15. The shock absorber according to claim 12, wherein a valve arrangement, in particular a solenoid valve or a proportional flow control valve, is provided for controlling the flow resistance of the working medium in the first valve arrangement, said valve arrangement being arranged between a pressure line connected at the lower connection element and a pressure line connected at the upper connection element.

16. The shock absorber according to claim 12, wherein the hydraulic pump drive comprises a controllable pump and a motor for the pump.

17. The shock absorber according to claim 12, wherein a non-return valve or a control valve respectively is arranged between the feed line and at least one of the lower pressure line and the upper pressure line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1: shows a shock absorber according to the prior art,

(3) FIG. 2: shows a first embodiment example of a shock absorber according to the invention,

(4) FIG. 3: shows a second embodiment example of a shock absorber according to the invention,

(5) FIG. 4: shows a third embodiment example of a shock absorber according to the invention,

(6) FIG. 5: shows a fourth embodiment example of a shock absorber according to the invention, and

(7) FIG. 6: shows a vehicle seat equipped with a suspension, in which a shock absorber according to the invention is fitted.

DETAILED DESCRIPTION

(8) FIG. 2 shows a first embodiment example of a shock absorber according to the invention. The shock absorber basically consists of a housing 1, which is tubular and in which an inner pipe 2 (not shown here) arranged inside the housing (1) is arranged so as to be stationary. In this case, the inside of the housing (1) is formed in principle like that of the prior art according to FIG. 1. A piston 5 can be moved backwards and forwards in the inner pipe 2 by means of a piston rod 6, the inner pipe being separated by the piston 5 into an upper chamber 4 and a lower chamber 3. In this case, the inner pipe 2 is completely filled with a working medium, preferably with an oil. In this case, a first valve arrangement 9 is mounted in the piston 5. Said valve arrangement 9 is designed so that the oil can pass through it in both directions. Since additional oil is displaced when moving the piston 5 in the inner pipe 2 from top to bottom by means of the piston rod 6, the oil must have the opportunity to escape out of the upper chamber 4. For this purpose, a second valve arrangement 8 is provided at the upper end of the inner pipe 2, by means of which valve arrangement oil can escape out of the upper chamber into the container 1 serving as a tank. In this case, the valve arrangement 8 is designed only to allow oil to pass in this direction. It is not possible for oil to pass from the container 1 into the upper chamber 4 of the inner pipe 2 via the valve arrangement 8. Since, when the piston 5 is moved inside the inner pipe 2 from bottom to top, the lower chamber 3 increases in volume whilst the upper chamber decreases in volume, a third valve arrangement 7 is provided at the lower end of the inner pipe 2. It is thus possible for oil to enter into the lower chamber 3 of the inner pipe 2 from the container 1 in which it is stored, whilst, due to the reduced volume of the upper chamber 4, oil found here reaches the container 1 via the valve arrangement 8.

(9) In contrast to the housing from the prior art according to FIG. 1, this embodiment example comprises a connection element 12 on the upper chamber 4 of the inner pipe 2, and a connection element 13 on the lower chamber 3 of the inner pipe 2.

(10) At the connection elements 12 and 13, a hydraulic pump drive is connected to the piston 5 as a device for controlling the flow resistance of the working medium or oil in the valve arrangement 9 respectively.

(11) In the present case, the hydraulic pump drive consists of a controllable pump 15 and a pump motor 16. In this case, the pump 15 is reversible so that it can pump oil out of the lower chamber 3 into the upper chamber 4 of the inner pipe 2 as well as in the opposite direction. By means of a pump 15 of this kind, for a defined stroke of the piston 5 inside the inner pipe 2, amounts of oil exchanged between the lower chamber 3 and the upper chamber 4 can be increased or reduced respectively. On the one hand, this causes the damping forces to be increased/reduced in response to the introduction of the oil; on the other hand, a height correction, in particular a seat height correction can take place in this embodiment example when a damper of this kind is used on a seat, or a temporary adjustment of the shock absorber can be generally carried out.

(12) Since a certain leakage rate must also always be taken into account in pump systems, a leakage pipe 21 is also provided in the embodiment examples according to FIGS. 2 to 5, by means of which oil escaping from the pump 15 can be returned into housing 1 serving as a tank for the oil.

(13) In addition, the embodiment examples in FIGS. 4 and 5 comprise a feed line 20, by means of which the pump 15 can be supplied with any necessary amount of feed oil during operation. In this case said feed line 20 comprises connections to the pressure lines 17 and 18, said pressure lines being separated from one another by means of non-return valves or control valves 19 respectively which are used for flow rate compensation or pressure compensation respectively.

(14) FIG. 5 shows a further embodiment example of a shock absorber according to the invention. In addition to the above-described hydraulic pump drive, a proportional flow control valve is provided here in parallel with said pump drive on the pressure lines 17 and 18 as a device for controlling the flow resistance of the working medium in the valve arrangement 9 of the piston 5, which proportional flow control valve is arranged between a pressure line 18 connected at the lower connection element 13 and a pressure line 17 connected at the upper connection element 14. By means of a proportional flow control valve 22 of this kind, it is possible to control the flow resistance of the oil therein according to the flow strength. In this respect it is hereby possible to adjust the performance of the shock absorber and thus the damping according to the required loading conditions by means of said proportional flow control valve 22. A passive default setting of the shock absorber is provided here as a hard setting, the shock absorber achieving its highest performance in this flowless state. When the proportional flow control valve 22 is activated, the damping forces are reduced, since a certain proportion of the oil exchange between the chamber 3 and the chamber 4 is diverted through the pressure lines 17 and 18 and the proportional flow control valve 22, without flowing through the hydraulic pump arrangement. The stronger the flow, the more oil can flow through the proportional flow control valve, so that the shock absorber is adjusted to be softer as the flow strength increases. The shock absorber can therefore be operated both semi-actively and passively.

(15) In addition, all the embodiment examples in FIGS. 2 to 5 comprise a rising pipe 14 arranged on the upper end of the inner pipe 2, which rising pipe protrudes through an oil sump level 11 into the oil sump 10 inside the container 1. Said rising line 14 is used to ensure that no cavitation occurs during external operation of the shock absorber, in which the amount of oil is exchanged between the lower chamber 3 and the upper chamber 4 by means of a hydraulic pump. Cavitation of this kind would be disadvantageous for the operation of the shock absorber. In addition, said rising pipe 14 ensures a closed oil circuit even during external operation.

(16) A vehicle seat 30 is shown in FIG. 6, which has suspension 32, the vibrations of which are damped by means of a shock absorber 31 according to the invention.

LIST OF REFERENCE NUMERALS

(17) 1 Housing 2 Inner pipe 3 Chamber 4 Chamber 5 Piston 6 Piston rod 7 Valve arrangement 8 Valve arrangement 9 Valve arrangement 10 Oil sump 11 Oil sump level 12 Connection element 13 Connection element 14 Rising pipe 15 Pump 16 Motor 17 Pressure line 18 Pressure line 19 Non-return valve 20 Feed line 21 Leakage pipe 22 Proportional flow control valve