JPH03500758A - Steering device for front and rear wheels that allows the vehicle to be steered freely - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Steering device for front and rear wheels that allows the vehicle to be steered freely [Technical field] The present invention provides a steering system having a steering system for steering front wheels and rear wheels. The present invention relates to a conventional front wheel and rear wheel steering device.

[Conventional technology]

The electrical signals from the front wheel steering angle detector, rear wheel steering angle detector and vehicle speed detector are Guided by child controller. Therefore, these signals electrically control the control valve of the rear wheel steering system. Served to operate in a formal manner. The transmission ratio of the steering angle of the front wheels and rear wheels depends on the driving speed. can be changed in relation to Such a steering device is disclosed in a patent application published in the Federal Republic of Germany. Already known in Publication No. 3506048〇 In this type of device, there is a mechanical coupling element between the front wheel steering device and the rear wheel steering device. Since there is no such thing, the steering device can be easily installed in the vehicle. Shikaji hydraulic system In the unlikely event of a failure in the steering control, the rear wheels could quickly turn uncontrollably. There is a risk of

[Disclosure of the invention]

The object of the invention is to provide a known type of steering device for steerable front and rear wheels. Even if there is no mechanical coupling element between the front wheel steering device and the rear wheel steering device, Ensures accurate adjustment of the rear wheels without any appreciable load on the front wheel steering system. The aim is to improve the Here, we will calculate the relationship between the steering angles of the rear wheels and front wheels depending on the vehicle speed. It is intended to be relevant and changeable.

This object is achieved by a steering device according to claim 1. The scope of the claims Advantageous embodiments are described in the embodiment section. However, the present invention The invention is not limited to the features set forth in the claims. A person skilled in the art should understand the scope of each claim. It can be implemented by combining the features of the boxes.

The objective solution of the invention is in particular for controlling the steering motor of a rear wheel steering device. In addition to the electric control signal, the control valve is equipped with a transmission cylinder that is linked to the front wheel steering system. The hydraulic control signals of these are to be guided. This allows a very precise adjustment of the rear wheel. In addition to the adjustable electrical circuit, a fast and reliable hydraulic control circuit is created.

When the sending cylinder moves, the contracting working chamber of the sending cylinder is controlled through the control valve. Connected to one working chamber of the steering motor, the increasing working chamber of the sending cylinder is connected to the rear wheel Connected to the pressure side of the steering gear servo pump. This causes the outgoing cylinder to The movement is assisted by a pressure medium conveyed by a servo pump and an outgoing cylinder Da's piston rod requires almost no force.

Adjust the piston surface of the control valve's actuating piston to match the area ratio of the sending cylinder and steering motor. By combining, balanced and unbalanced type sending cylinder or steering motor is available.

Controlled by an electronic controller to compensate for synchronization errors exceeding predetermined limits At least one pump driven by an electric motor is provided. This pon The hydraulic circuit is supplied with a carrier flow from the pump, precisely regulated to compensate for hydrostatic leakage losses. A fixed amount of pressure medium can be introduced.

A device for changing the transmission ratio of steering angles between front wheels and rear wheels is defined in claim 7 and and the steering link according to paragraph 8. According to this embodiment, the steering The piston rod of the motor can also be guided vertically, so there is no vertical movement to the rotation axis. Does not occur.

An electronic control unit adjusts the adjustment deviation between the front wheel steering device and the rear wheel steering device to a predetermined tolerance. To avoid malfunctions in the event of a failure that prevents the unit from performing its maintenance work. , and redundant front wheel steering angle to further increase the safety of the steering system. Detector, rear wheel steering angle detector, vehicle speed detector, and position detection for the position of the rotation axis It has an outlet. The electrical signals of these detectors are routed to an auxiliary electronic control unit, which This electrically operates the mechanical locking device for the front wheel steering system, or Used to electrically actuate a hydraulic control device to return the wheels to their straight-ahead position. intended.

The present invention will be described in detail below with reference to a plurality of embodiments shown in the drawings.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a steering device based on the present invention, and FIG. 2 is a schematic diagram of a steering device according to the present invention. An enlarged sectional view of the control valve of the device, FIG. 3 is a schematic diagram of a different embodiment of the compensating pump of the steering gear in FIG. , Figure 4 is a cross-sectional view of a device for changing the transmission ratio of the steering angle between the front wheels and the rear wheels. Figure 5 is a sectional view taken along the v-v line in Figure 4, and Figure 6 is a rudder corresponding to Figure 1. A schematic configuration diagram of an embodiment having an auxiliary backup circuit for the removal device, Figure 7 shows different types of steering gear with a steering motor that can be locked by two valves. FIG. 8 is a schematic configuration diagram of an embodiment according to the present invention, and FIG. 8 is a steering device corresponding to FIG. Schematic configuration of an embodiment with a steering motor that can be moved freely in the switching position of the valve. It is a diagram.

[Best mode for carrying out the invention]

As shown in FIG. 1, a front wheel steering device 1 includes a steering transmission device 2 and a front wheel steering device The tie rod 4 is connected to the ring 3. The steering transmission device 2 In the exemplary embodiment it is hydraulically assisted by a servo pump 5. But at the helm The steering gear 2 may be a typical mechanical steering gear.

The rear wheel steering device 6 has a steering motor 7. The rear wheel 10 is connected to the steering motor 7 Therefore, the vehicle is steered via the steering link 8 and tie rods 9.

The front wheel steering device 1, in the case of this embodiment, the steering transmission device 2, is configured to control the front wheel steering angle. A detector 11 is arranged.

The rear wheel steering device 6, in this embodiment, the steering motor 7, detects the front wheel steering angle. A container 12 is arranged. Front wheel steering angle detector 11 and rear wheel steering angle detector 1 The electric signal No. 2 is the electric signal of the vehicle speed detector 14 connected to the tachometer 13 of the vehicle. Together with the signal, it is guided to the electronic control unit 15. These electrical signals are controlled by electronic control equipment. control valve 16 which is processed in step 15 and is used to control the steering motor 7; Used for electromagnetic operation.

A transmission cylinder 17 is connected to the tie rod 4 of the front wheel steering device 1 . This issue A hydraulic control signal is introduced from the signal cylinder 17 to the control valve 16 via the control pipes 18 and 19. It will be destroyed.

Next, the structure of the control valve 16 will be explained with reference to the embodiment shown in FIG.

A valve spool 21 is movably disposed within a valve housing 22. central spool The groove 23 is connected to a return passage leading to a reservoir 24. The control valve 16 is Housing grooves 25. are provided on the left and right sides of the central spool groove 23, respectively. It has 26. child These grooves 25 and 26 are connected to the servo used for pressure adjustment via the spool grooves 27 and 28. It is connected to two pressure pipes of the pump 30. Spool groove 27. Following 28 housing grooves 3-1.32 are formed, and these housing grooves 31.3 2 are connected to each one of the transmitting cylinders 17 via control pipes 18 and 19, respectively. Connected to a pressure chamber. Spool groove 33.34 following housing groove 31.32 are respectively connected to the pressure of one side of the steering motor 7 via the working pipes 35 and 36, respectively. connected to the room. Both end surfaces 37 of the valve spool 21. 2 connected to 3g The two housing chambers 39 , 40 are connected to the return passage to the reservoir 24 .

The operation of the control valve 16, that is, the movement adjustment of the valve spool 21, is performed at both ends of the valve spool 21. This is done via two actuating pistons 41, 42 connected to surfaces 37, 38. . The outer end faces 43, 44 of the actuating piston 41.42 are connected to the control line 18.19. The pressure applied to the pressure chamber of the transmitting cylinder 17 through the working pipes 45 and 46 energized by force.

The grooves of the control valve 16 and the lands between them start from the neutral position of the control valve 16. and has a width such that the next control sequence is achieved. That is, in the neutral position , the pressure medium from the servo pump 30 flows through the spool grooves 27 and 28, and the housing groove 2. 5.26 and spool groove 23 into reservoir 24. valve spoo When the housing groove 21 is moved from the neutral position, for example to the right, the housing groove 25 and the middle Communication with the central spool groove 23 is reduced.

After that, the right side of the sending cylinder 17 is passed from the spool groove 28 to the housing groove 32. Pressure is supplied to the pressure chamber. Next, from the left control pipe 18 to the housing groove 31 and Pressure is supplied to the left working pipe 35 via the spool groove 33 .

Finally, the reservoir is passed from the right side working pipe 36 through the spool groove 34 and the housing chamber 40. A connection to 24 is made. suitable for the purpose, in the spool groove of the valve spool 21. The control edge is provided with a control step (not shown). Valve spool 21 moves to the left. Even when the engine is running, control is performed in the same control order as described above.

Electric actuation of the control valve 16 is performed by an electric control arrangement from an electronic control unit 15 in FIG. It is simply indicated by the pipe 47 leading to the control valve 16. In Figure 2 In the embodiment shown in FIG. It is divided into two wiring parts 47A and 47B used for electric motor 48 A.

Two compensation pumps 49A and 49B are driven by 48B. compensation pump 49 The pressure side of A is connected to the operating pipe 45 or the control pipe 18 via the check valve 5o. There is.

Similarly, the compensation pump 49B is connected to the operating pipe 46 or the control pipe via the check valve 51. It is connected to 19.

In the embodiment of FIG. 3, both compensation pumps 49A.

49B are combined into a single compensation pump 49 that conveys in both rotational directions. this The compensation pump 49 is powered by a single electric motor 48 which is controlled via electrical control wiring 47. is driven. In this embodiment, each compensation pump 4 is connected to both suction lines. Check valves 52 and 53 that open in the direction of the suction side of 9 must be installed.

The working surfaces of both actuating pistons 41, 42 are in contact with the effective surface of the transmitting cylinder 47. It has the same area ratio as the effective surface of the motor 7.

Next, the structure of the steering link 8 is shown in the principle diagram in Fig. 1 and in Figs. 4 and 5. The invention will now be described with reference to particularly advantageous embodiments. The steering link 8 is hinged at one end. The hinge point 55 is in contact with the piston rod 56 of the steering motor 7. It is continued. Two hinge points 5 are located at a predetermined distance from the other end of the steering link 8. 7.58 are arranged, and these hinge points 57.58 have a steerable rear Two tie rods 59 and 60 leading to the ring 10 are hinged together. steering The rotation axis 61 of the steering link 8 is moved in the slot 62 in the longitudinal direction of the steering link 8. I can move. This movement of the rotation axis 61 is driven by, for example, an adjustment motor 63. This is done by means of a screw transmission. The regulating motor 63 is controlled by an electronic control device 64. It is controlled by an electric signal from the vehicle speed detector 14.

In FIG. 4, the housing 65, which is rigidly connected to the vehicle frame, is connected to the regulating motor 6. I support 3. The regulating motor 63 has two spur gears 66, 67 and 67. driving a first threaded spindle 69 via a spline 68 provided in the . This threaded spindle 69 rotates when it is rotated. 70 relative to the housing 65. The threaded spindle 69 has , th], the bevel gear housing 71 is coupled rotatably but immovably in the axial direction. has been done. Inside this first bevel gear housing 71 is a first bevel gear device 7. 2, this bevel gearing 72 is rigidly connected to a threaded spindle 69. It consists of a first bevel gear 73 and a second bevel gear 75 that meshes with the first bevel gear 73. Second The bevel gear 75 is connected to a third bevel gear 77 via an intermediate shaft 76 . child The third bevel gear 77 connects the second bevel gear device 79 together with the fourth bevel gear 78. is forming. The fourth bevel gear 78 connects to the second threaded spindle via a screw 80. It is tied to $81. The screw 80 of the second threaded spindle 81 is is the same as the thread 70 of the threaded spindle 69 but has an opposite pitch. Ru.

The second bevel gear device 79 is supported by the second bevel gear housing 82 . No. The bevel gear housing 82 of 2 has a journal 83, and this journal 8 3 to the first threaded spindle 69 in the slot 84 of the housing 65. It is movably supported in parallel to the housing 65. second bevel gear The housing 82 rotates with respect to the first bevel gear housing 71 via a bearing 85. freely supported.

A second threaded spindle 81 is rigidly connected to a frame lever 86. this frame The shaped lever 86 serves as the steering link 8. A hinge point at one end of the frame lever 86 55 are arranged. The piston rod 56 of the steering motor 7 is a fork-shaped spatula. It is hinged to the hinge point 55 via a door 87 . This combination allows the second The threaded spindle 81 is held non-rotatably with respect to the housing 65. Ru. To attach tie rods 59 and 60 to both longitudinal sides of the frame lever 86. Two hinge points 57 and 58 are provided.

The axes of the journal 83 and the intermediate shaft 76 form the rotation axis 61 of the frame lever 86. are doing. To prevent the threaded spindle 69.81 from getting dirty, 88 and housing extensions 89,90 are provided.

In order to further improve the safety of the steering device shown in FIG. 1, the embodiment shown in FIG. In this case, an auxiliary backup circuit is provided. There are no same parts in Figure 6 as in Figure 1. Corresponding parts are given the same reference numerals as in FIG. Auxiliary redundant components are disclosed with the same numerals added by 100. In other words, front wheel steering angle inspection output device 111, rear wheel steering angle detector 112, vehicle speed detector 114, and electric control signal 115 is shown. For this purpose, there is also a position detector 91, which is suitable for the purpose. Disposed within housing extension 90 of housing 65 . The position detector 91 Provides electrical and electrical signals to the auxiliary redundant electronic controller 115. By this control signal The position of the first threaded spindle 69 and the rotation axis 61 of the steering link 8 The position is transmitted to electronic control unit 115. Electronic control circuit 115 distributes electrical control signals. A hydraulic control device 93 is supplied via line 92 and a mechanical locking device is supplied via line 94. Supply to 95. In the event of a failure, no electrical signal of the electronic control unit 115 is generated.

This causes the mechanical locking device 95 and the hydraulic control device 93 to operate.

7 and 8, two embodiments for the hydraulic control device 93 are shown in FIG. The steering gear is shown schematically as shown in FIG. Both working pipes 35.36 Electromagnetic switching valves 93A and 93B are driven via wiring 92A and 92B, respectively. is located. Both electromagnetic switching valves 93A and 93B are shown here for clarity. shown as two separate valves, but can also be made as one common valve. Wear. Both electromagnetic switching valves 93A, 93B are not energized in the position shown in FIG. This opens a passage from the control valve 16 to the steering motor 7. current is interrupted When the spring force is applied, the steering motor 7 is hydraulically locked and the actuation line 35. 36 leads to the reservoir 24.

As a result, the sending cylinder 17 is activated even though the steering motor 7 is locked. You can move freely.

Fig. 8 differs from Fig. 7 in that it uses a hydraulic system to free the steering motor 7 in the event of a power outage. It shows. Solenoid switching valves 93C and 93D were moved by spring force during a power outage. When in position, the pressure chambers on both sides of the steering motor 7 are connected to each other and to the reservoir 24 be done. Here, the steering motor 7 is mechanically controlled by a mechanical locking device 95. placed in the central position.

Next, the operation of the steering device according to the present invention will be explained.

In the steering process introduced by the steering transmission 2 of the front wheel steering device 1, The piston rod of transmitting cylinder] 7 is moved to the left side, for example, and thus The end surface 43 of the left actuating piston 41 is connected via the control pipe 18 and the actuating pipe 45. , is energized by the pressure in the left pressure chamber of the transmitting cylinder 17. This allows the actuating piston to The ton 41 and the valve spool 21 are moved to the right. Depending on the control order mentioned above , the right pressure chamber of the sending cylinder 17 receives the pressure conveyed by the servo pump 30. Depending on the medium, pressure line 29, spool groove 28, housing groove 32 and control arrangement It is energized via tube 19. The pressure introduced into the right working chamber of the sending cylinder 17 is , the piston of the sending cylinder 17 supports the movement of the initially introduced piston rod. Stone rods do not always require force. On the other hand, the housing groove 31 and the spool groove 33 After communication between the spool groove 34 and the housing chamber 40 is established, the rudder The take-up motor 7 has the pressure and reservoir of the servo pump 30 conveyed to the sending cylinder 17. The total pressure difference between the two and the first and second holes 24 acts.

The movement adjustment speed of this device mainly depends on the transfer capacity of the servo pump 30, and is very Can be made high. Here, the amplitude and direction of the movement adjustment of the steering motor 7 are determined by the sending cylinder 1. 7 adjustments are guaranteed to be accommodated unambiguously. This means that the steering motor 7 Unlike conventional technology, this technology does not cause uncontrollable movements without special treatment. Taste. The movement of the steering motor 7 is always controlled by the steering transmission 2 of the front wheel steering device 1. It is also assumed that the steering movement in Even if the servo pump 30 stops , still gives significant movement of the rear wheel, although this is supported by the servo pump. This is provided by the increased steering force in the front wheel steering device 1 without assistance.

The most unavoidable leakage losses occur when no auxiliary measures are taken. , the synchronization between the front wheel steering device 1 and the rear wheel steering device 6 is gradually lost.

Therefore, in parallel with the above-mentioned steering process, the built-in electronic circuitry ensures that the vehicle is always In relation to the speed, the position of the front wheel steering angle detector 11 is the position of the rear wheel steering angle detector 12. and is compared by the electronic control unit 15. A synchronization error exceeding the tolerance limit is generated. When this occurs, the electric motors 48A and 48B are driven as electric regulating elements, and Control line IB via compensating pumps 49A, 49B acting as.

A corresponding hydraulic compensation between 19 and 19 is carried out. Here, unlike the action of hydrostatic pressure control, Therefore, the compensation flows from the compensation pumps 49A and 49B are intentionally designed to reduce hydrostatic leakage losses. It can be made just large enough to be compensated. This allows it to act as a synchronization regulator. Even when the electronic control device 15 malfunctions, the momentary uncontrollable steering of the rear wheels 10 is prevented. can definitely be avoided.

By adjusting the position of the rotation axis 61 of the steering link 8, general four-wheel steering can be achieved. The steering can be switched to dog walking type steering. The rotational axis 61 is in the position shown in FIG. , the rear wheels 10 are adjusted in the same way as the front wheels 3 (dog-walking steering). . On the other hand, the rotation axis 61 is moved below the hinge point 57, 58 by the adjusting motor 63. When moved to the side position, the rear wheels 10 are turned in the opposite direction with respect to the front wheels 3 (4-wheel steering).

Adjustment of the position of the rotation axis 61 is performed, for example, as follows in FIG. 4. Immediately When the adjusting motor 63 is activated, both the gears 66, 67 and the splines A first threaded spindle 69 is rotated via 68 . This spinning luck The movement is converted into a displacement movement of the threaded spindle 69 via the screw 70. screw With spindle 69, first bevel gear housing 71 and both bevel teeth The second bevel gear housing 82 is also 1 threaded spindle 69. second threaded spin The dollar 81 is immovable relative to the housing 65 but rotates around the rotation axis 61. can. The position adjustment method of the rotation axis 61 is the frame lever shown in FIGS. 4 and 5. In the case of It's appropriate.

Explanation of symbols 1 Front wheel steering device 2 Steering transmission device 3 Front wheel 6 Rear wheel steering device 7 Steering motor 8 Steering link 9 Tie rod 10 Rear wheel 79 Second bevel gear device 80 screw 81 Second threaded spindle 82 Second bevel gear housing 83 Journal 84 slot 85 Bearing 86 Frame lever 87 Forked head 88 bellows 89, 90 Housing extension part 91 Position detector 92.92A, 92B wiring 93 Hydraulic control device 93.93A, 93B Solenoid switching valve 94 Wiring 95 Mechanical locking device FIG.1 international search report international search report

Claims (1)

[Claims] 1. Front wheel steering device (1), hydraulically assisted rear wheel steering device (6), front wheel steering device Steering angle detector (11), rear wheel steering angle detector (12), vehicle speed detector (14), To change the transmission ratio of the steering angle between the front wheels (3) and the rear wheels (10) in relation to the running speed device, and a steering motor (7) of a rear wheel steering device (6) and a rear wheel that can be freely steered. (10), each of the detectors (11, 1 2, 14) are led to the electronic control circuit (15), where the rear wheel steering system (6) Vehicle steering as provided for electrically actuating the control valve (16) of In a steering device for freely movable front wheels (3) and rear wheels (10), A control valve (16) for controlling the steering motor (7) of the rear wheel steering device (6). , in addition to the electric control signal, a transmission cylinder (1) linked to the front wheel steering device (1) 7) A steerable front wheel of a vehicle, characterized in that a hydraulic control signal is guided from the vehicle. and rear wheel steering device. 2. The control valve (16) controls the transmission cylinder (17) when the transmission cylinder (17) moves. The shrinking working chamber of 17) is connected to one working chamber of the steering motor (7), and The pressure side of the servo pump (30) of the steering gear (6) is connected to the transmitting cylinder (17). The other working chamber of the steering motor (7) is connected to a large working chamber, and the other working chamber of the steering motor (7) is connected to a reservoir ( 24) A claim characterized in that the claim is configured to be connected to a return path to The steering device according to item 1. 3. The control valve (16) is equipped with two actuating pistons (41, 42), which These piston surfaces are the effective surface of the sending cylinder (17) and the steering motor (7). Claim 2, characterized in that the area ratio is the same as that of the effective surface. The steering device on board. 4. In order to compensate for synchronization errors exceeding predetermined limits, an electronic control device (15) At least one compensating pump (49) controlled by and electrically driven is provided. The carrier flow is controlled between the sending cylinder (17) and the control valve (16). Claim 2, characterized in that it is led to one of the control pipes (18, 19). steering gear. 5. Two compensation pumps (49A, 49B) are provided, each with a The steering wheel according to claim 4, characterized in that the steering wheel is connected to one connecting pipe. equipment. 6. the compensation pump (49) is one pump that conveys in both rotational directions; , its both side connection ports are connected to the reservoir (24) via check valves (52, 53), respectively. The steering device according to claim 4, characterized in that: 7. The steering wheel is a device for changing the transmission ratio of the steering angle between the front wheels (3) and the rear wheels (10). The steering link (8, 86) is formed by the steering link (8, 86). hinge point (55) for the movable part of the motor (7), passing through the rear wheel (10). at least one hinge point (59,60) to the tie rod (59,60) ) and the adjusting motor (63) to move the steering link (8, 86). The rotation axis (61) has a constant rotation axis (61), and the rotation axis (61) has a 61) is moved, the piston rod (56) and tie rods (59, 6 0) is characterized in that the hinge points (55, 57, 58) remain unchanged. A steering device according to claim 1. 8. A first threaded spindle (69) is located within the housing (65) with a regulating motor ( 63) so as to be movable in the longitudinal direction, and the first bevel gear housing ring (71) has a first bevel gearing (72) and a first threaded spindle. The second bevel gear housing can be moved relative to the housing (65) together with the housing (69). The intermediate shaft (76) has a ring (82) extending from the first bevel gear housing (71). ) and a journal (8) guided in the slot (84) of the housing (65). 3) and is rotatably supported by the first threaded spindle (69). It can be moved in parallel, thereby aligning the axes of the intermediate shaft (76) and journal (83). It forms the rotation axis (61) of the steering link (8, 86), and has a second threaded The spindle (81) is connected to the second bevel gear housing (82) via the screw (80). ), which is coupled to a second bevel gear arrangement (79) located within the housing. (65) and swingably about the rotation axis (61). the frame-shaped lever (86) is firmly connected to the second threaded spindle (81); A rudder according to claim 7, characterized in that it forms a steering link (8). Removal device. 9. Auxiliary redundant front wheel steering angle detector (111), rear wheel steering angle detector (112) ), the rotation axis (61) related to the vehicle speed detector (114) and the regulating motor (63) ) is provided with a position detector (91) for the position of the auxiliary electronic guided to a control device (115) where mechanical locking for the rear wheel steering device (6) In order to electrically activate the device (95), the rear wheels (10) are moved to their straight-ahead position. be provided for electrically operating the hydraulic control device (93) for returning the A steering device according to claim 1, characterized in that: 10. an actuating pipe (35, 3) connecting the control valve (16) to the steering motor (7); 6) are equipped with electromagnetic switching valves (93A, 93B; 93C, 93D) that operate in the event of a power outage. By means of these switching valves, both working chambers of the steering motor (7) are locked or connected to each other. as claimed in claim 2, characterized in that it is arranged so as to be coupled to Steering device.