A device for use in the rotation of a steering-capable vehicle wheel

Abstract

A device for use in rotating a steerable vehicle wheel includes a steering member connected to at least one steerable vehicle wheel. The steering member is moved axially to perform rotational movement of at least one steerable vehicle wheel. The steering member has an external threaded portion. A ball nut assembly is connected to the external threaded portion of the steering member. The ball nut assembly can be rotated relative to the steering member to move the steering member axially. In response to the rotation of the steering wheel, a first gear member can be rotated. A second gear member disposed in meshing with the first gear member is rotated in response to the rotation of the first gear member. The ball nut assembly is rotated relative to the steering member in response to the rotation of the second gear member.

Description

Technology Field

[0001] The present invention relates to a device for use in the rotation of a steerable vehicle wheel, and more specifically, to an electric power steering gear for use in the rotation of a steerable wheel of a vehicle, particularly a commercial vehicle such as a heavy truck. Background Technology

[0002] A known vehicle steering device includes a steering member that can be utilized axially to perform rotational movement of a steerable vehicle wheel. A pinion is disposed in an engagement with a rack portion of the steering member. A steering column interconnects the pinion with the vehicle steering wheel. A ball nut assembly is connected to an external threaded portion of the steering member. A motor is connected to the ball nut assembly. The motor can be operated to perform rotation of the ball nut assembly relative to the steering member so that the steering member moves axially relative to the vehicle. A steering device having such a general configuration is disclosed in U.S. Patent No. 7,055,646. means of solving the problem

[0003] The present invention relates to an apparatus for use in the rotation of a steerable vehicle wheel, comprising a steering member connected to at least one steerable vehicle wheel. The steering member is moved axially to perform rotational movement of at least one steerable vehicle wheel. The steering member has an external threaded portion. A ball nut assembly is connected to the external threaded portion of the steering member. The ball nut assembly can be rotated relative to the steering member to move the steering member axially. In response to the rotation of the steering wheel, a first gear member can be rotated. A second gear member disposed in meshing with the first gear member is rotated in response to the rotation of the first gear member. The ball nut assembly is rotated relative to the steering member in response to the rotation of the second gear member.

[0004] A device for use in the rotation of a steering vehicle wheel may include an electric motor connected to a ball nut assembly. The motor is operated to apply rotational force to the ball nut assembly, thereby causing the ball nut assembly to rotate relative to a steering member.

[0005] The second gear member may have a first gear that meshes with the first gear member, and a second gear that meshes with a third gear member connected to a ball nut assembly. The third gear member may be connected to a ball nut assembly and may rotate with respect to the steering member together with the ball nut assembly. Brief explanation of the drawing

[0006] The foregoing and other features of the present invention will become more apparent to those skilled in the art related to the present invention when understanding the following description with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a device for rotating a steerable vehicle wheel configured according to a first embodiment of the present invention. Figure 2 is an enlarged view of the device of Figure 1. Specific details for implementing the invention

[0007] A device (10) for use in the rotation of a steerable vehicle wheel configured according to the present invention is illustrated in FIGS. 1 and 2. The device (10) includes a steering column (14) connected to a steering wheel (16). The steering column (14) is also connected to an input member (18) of a gearbox (20). The input member (18) ( FIG. 2) is supported by a bearing (22) for rotation about the axis (24) of the input member relative to the housing (26) of the gearbox (20). When the steering wheel (16) rotates, a force is transmitted to the input member (18) through the steering column (14) to induce rotation of the input member relative to the housing (26).

[0008] The input member (18) is connected to the first end of the torsion bar (30). The second end of the torsion bar (30) is connected to the first gear member (32). The first gear member (32) is supported by a bearing (34) for rotation about an axis (24) relative to the housing (26). The torsion bar (30) enables relative rotation between the input member (18) and the first gear member (32). Although the device (10) is described as including a torsion bar (30) that allows relative rotation between the input member (18) and the first gear member (32), it is considered that the first gear member may be directly connected to the input member (18). The first gear member (32) may be a bevel gear that can rotate relative to the housing (26) under the influence of a force transmitted through the steering column (14) and the input member (18).

[0009] The first gear member (32) can mesh with the gear (40) on the first axial end of the second gear member (42). The second gear member (42) is supported by a bearing (46) for rotation about an axis (44) relative to the housing (26). The axis (44) may extend transversely to the axis (24) and generally perpendicularly to the axis (24). The gear (40) on the second gear member (42) may be a bevel gear that can rotate about the housing (26) around the axis (44) under the influence of the force transmitted through the steering column (14), the input member (18), and the first gear member (32). The gear members (32, 42) can increase the torque applied to the input member (18) and the steering column (14).

[0010] The second gear member (42) has a gear (48) on the second axial end. The gear (48) rotates together with the gear (40) and the second gear member (42) about the housing (26) around the axis (44). The gear (48) meshes with the third gear member (50) connected to the ball nut assembly (52). The ball nut assembly (52) rotates together with the third gear member (50) under the influence of the force transmitted through the steering column (14), the input member (18), and the first and second gear members (32, 42). Although the third gear member (50) is described as being connected to the ball nut assembly (52), it is taken into consideration that the third gear member may be formed on the ball nut assembly (52).

[0011] The ball nut assembly (52) extends within the tubular housing (60). The ball nut assembly (52) is supported to rotate relative to the housing (60) by a bearing (62). The bearing (62) supports the ball nut assembly (52) to rotate about an axis (64) that extends generally parallel to the axis (44) of the second gear member (42). The bearing (62) is coupled with a shoulder (66) on the inner side of the housing (60) and an end cap (68) of the housing to prevent the ball nut assembly (52) from moving axially relative to the housing.

[0012] The ball nut assembly (52) extends around the external threaded portion (70) of the steering member (72). The steering member (72) is connected to at least one steerable vehicle wheel in any desired manner. The steering member (72) can be moved axially within the housing (60) along the axis (64). The ball nut assembly (52) comprises a plurality of balls arranged to engage with the external threaded portion (70) of the steering member (72). Rotation of the ball nut assembly (52) relative to the housing (60) and the steering member (72) is performed to move the steering member axially with respect to the ball nut assembly and axially with respect to the housing.

[0013] A reversible electric motor (80) is operated to apply rotational force to a ball nut assembly (52), so that the ball nut assembly can be rotated relative to the steering member (72) and the housing (60). The electric motor (80) (Fig. 2) has an output shaft (82) connected to a drive pulley (84). The drive pulley (84) is connected to a driven pulley (88) by a drive belt (90). The driven pulley (88) is connected to the ball nut assembly (52). It is considered that the driven pulley (88) may be connected to a gear (50). Accordingly, the driven pulley (88) rotates relative to the housing (60) and the steering member (72) together with the ball nut assembly (52). The drive belt (90) transmits force to the ball nut assembly (52), causing the ball nut assembly to rotate around the axis (64) during the operation of the motor and the rotation of the drive pulley (84). It is considered that the motor (80) can apply rotational force to the ball nut assembly (52) in any desired manner.

[0014] It is considered that the gearbox (20) may be connected to a cover (96) for the drive belt (90) and pulleys (84, 88). The cover (96) may be connected to a support member or plate (98). The electric motor (80) and the housing (60) may be connected to the support member (98). The electric motor (80) may be connected to the support member (98) so that the output shaft (82) extends generally parallel to the steering member (72). The support member (98) connects the gearbox (20), the housing (60), and the motor (80) to the vehicle.

[0015] The device (10) (Fig. 1) may include two vehicle condition sensors (100, 102) and an electronic control unit (104) (ECU) for controlling the motor (80) based on the detected vehicle conditions. The vehicle condition sensors (100, 102) may include a torque sensor (100) and a position sensor (102) electrically connected to the ECU (104). The torque sensor (100) can detect the torque applied to the steering wheel (16) and can generate a signal indicating the torque. The position sensor (102) can detect the rotational position of the steering wheel (16) and can generate an electrical signal indicating the steering wheel position. Electrical signals from the torque sensor (100) and the position sensor (102) are transmitted to the ECU (104). The ECU (104) analyzes the output of the sensors (100, 102) and performs the operation of the motor (80) according to the output of the sensors. Although the sensors (100 and 102) are depicted as being connected to the gearbox (20), it is considered that the sensors may be connected to the steering column (14). Additionally, it is considered that the operation of the motor (80) may be performed using only the torque sensor (100) or only the position sensor (102).

[0016] Additionally, the ECU (104) may have an input that varies according to the detected lateral acceleration of the vehicle (not shown) or other vehicle operating conditions. The ECU (104) receives a signal generated by a sensor and operates the motor (80) to apply an axial force to the steering member (72), thereby assisting in the rotation of the steerable vehicle wheel.

[0017] From the foregoing description of the present invention, those skilled in the art will recognize improvements, changes, and modifications. Such improvements, changes, and modifications at the current level of the art will be incorporated into the appended claims.

Claims

Claim 1 A device for use in the rotation of a steerable vehicle wheel, comprising: a steering member connected to at least one steerable vehicle wheel, wherein the steering member is moved axially to perform rotational movement of at least one steerable vehicle wheel, and the steering member has an external threaded portion; a ball nut assembly connected to the external threaded portion of the steering member, wherein the ball nut assembly is rotated relative to the steering member to move the steering member axially; and a first gear member capable of rotating in response to the rotation of the steering wheel. A device for use in the rotation of a steering vehicle wheel, comprising a second gear member arranged to be engaged with a first gear member, wherein the second gear member rotates in response to the rotation of the first gear member, and a ball nut assembly rotates with respect to a steering member in response to the rotation of the second gear member, and the second gear member has a first gear engaged with the first gear member, and a second gear engaged with a third gear member connected to the ball nut assembly, wherein the third gear member is connected to the ball nut assembly and can be rotated with respect to the steering member together with the ball nut assembly. Claim 2 A device for use in the rotation of a steerable vehicle wheel, wherein, in claim 1, it further comprises an electric motor connected to a ball nut assembly, and the motor is operated to apply rotational force to the ball nut assembly so as to cause the ball nut assembly to rotate relative to a steering member. Claim 3 delete Claim 4 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 1, the first gear of the first gear member and the first gear of the second gear member is a bevel gear. Claim 5 A device for use in the rotation of a steerable vehicle wheel, wherein the first gear of the first gear member and the first gear of the second gear member increases the torque applied to the steering column. Claim 6 A device for use in the rotation of a steerable vehicle wheel, wherein, in claim 1, the first gear member can be rotated around a first axis and the second gear member can be rotated around a second axis extending transversely to the first axis. Claim 7 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 6, the second axis extends generally parallel to the axis of the steering member. Claim 8 In claim 6, a device for use in the rotation of a steerable vehicle wheel, wherein the gearbox supports first and second gear members for rotation around the first and second axes. Claim 9 In paragraph 8, the gearbox has an input shaft connected to a first gear member, and the input shaft is connected to a steering wheel and can be rotated relative to the housing of the gearbox in response to the rotation of the steering wheel, a device for use in the rotation of a steerable vehicle wheel. Claim 10 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 8, a supporting member connects a housing that supports a gearbox, an electric motor, and a ball nut assembly for rotation to a vehicle. Claim 11 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 2, it further comprises at least one vehicle condition sensor and a control unit connected to at least one vehicle condition sensor, wherein at least one vehicle condition sensor provides an output to the control unit, and the control unit is connected to a motor and can be operated to control the operation of the motor according to the output from at least one vehicle condition sensor. Claim 12 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 2, at least one of a torque sensor for detecting a torque applied to a steering wheel and a position sensor for detecting the position of a steering wheel, and a control unit connected to at least one of the torque sensor and the position sensor, wherein at least one of the torque sensor and the position sensor provides an output to the control unit, and the control unit is connected to a motor and can be operated to control the operation of the motor according to the output from at least one of the torque sensor and the position sensor. Claim 13 A device for use in the rotation of a steerable vehicle wheel, wherein, in claim 1, the ball nut assembly extends within a tubular housing, and the ball nut assembly is supported for rotation relative to the housing and prevented from axial movement relative to the housing. Claim 14 delete Claim 15 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 2, the first gear of the first gear member and the first gear of the second gear member is a bevel gear. Claim 16 In paragraph 2, the first gear of the first gear member and the first gear of the second gear member is a device for use in the rotation of a steerable vehicle wheel, which increases the torque applied to the steering column. Claim 17 A device for use in the rotation of a steerable vehicle wheel, wherein, in paragraph 2, the first gear member can be rotated around a first axis and the second gear member can be rotated around a second axis extending transversely to the first axis.

Images