JP2014231307A - Power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power steering device having a structure which can improve fixing force of a torque sensor to a rotation shaft of a sensor sleeve, improving sealability of a seal member between a housing and a rotation shaft.SOLUTION: A power steering device 1 has a housing 20 through which a rotation shaft 10 for transmitting steering torque is inserted and sensor sleeves 80 attached to an outer peripheral surface of the rotation shaft 10, and also has a torque sensor 70 for detecting steering torque of the rotation shaft 10 and seal members 90 arranged between the outer peripheral surfaces of the sensor sleeves 80 and an inner peripheral surface of the housing 20. The seal members 90 have: main body portions 100 that are pressed into the outer peripheral surfaces of the sensor sleeves 80 and presses the sensor sleeves 80 from outside; first lip portions 101 that protrude from the main body portions 100 outside in a radial direction and contacts the inner peripheral surface of the housing 20; and second lip portions 102 that protrude from the main body portions 100 toward a torque input side in a shaft direction and contact the vertical surface of the housing portion 20.

Description

  The present invention relates to a power steering apparatus.

  A power steering device for a vehicle generates an auxiliary steering torque corresponding to a steering torque applied to a steering wheel by an electric motor and applies the auxiliary steering torque to an output shaft on a wheel side. For this reason, the power steering apparatus is provided with a mechanism for detecting the magnitude of the steering torque by the steering wheel.

  Specifically, an input shaft connected to the steering wheel and an output shaft linked to the wheel side are inserted into the housing, and the connecting portion between the input shaft and the output shaft is deformed according to the input side steering torque. Intervene bar. The torsion bar is fitted into a hole on the axis of the output shaft, and a tip portion protruding from the output shaft is fitted on the axis of the input shaft. A torque sensor that detects the steering torque by detecting the deformation amount of the torsion bar is provided on the outer surface of the output shaft that covers the torsion bar (see Patent Document 1).

  The torque sensor is a rotary non-contact torque sensor, and is arranged around the output shaft where the torsion bar is located. The sensor sleeve extends from the outer periphery of the output shaft to the outer periphery of the input shaft, and the outer periphery of the sensor sleeve. And a coil through which a current flows in accordance with the deformation of the torsion bar, a circuit board for detecting the current of the coil, and the like. The tip of the sensor sleeve is fixed to the groove on the outer peripheral surface of the input shaft by caulking.

  By the way, conventionally, in order to prevent foreign matter from entering the torque sensor, a seal member for preventing foreign matter from entering is provided between the inner peripheral surface of the housing and the outer peripheral surface of the input shaft. However, in this case, it is necessary to secure a space for the seal member on the outer peripheral surface of the input shaft, and the input shaft becomes longer correspondingly.

  Thus, as a structure that does not require a dedicated space for the seal member, there is a structure in which the seal member is disposed on the outer periphery of the sensor sleeve (see Patent Document 2).

International Publication No. 2007/074723 JP 2000-190857 A

  However, since the lip portion of the sealing member is in contact with the flange surface perpendicular to the axial direction, the sealing member with this structure does not have sufficient sealing performance when the sealing member moves in the axial direction, for example.

  In the case of the above-described structure, since the rotation of the sensor sleeve with respect to the input shaft is stopped by caulking of the sensor sleeve, there is a possibility that the sensor sleeve rotates when an excessive rotational torque is applied to the input shaft. is there.

  The present invention has been made in view of the above points, and provides a power steering device having a structure capable of improving the fixing force of the sensor sleeve to the rotating shaft while improving the sealing performance of the seal member between the housing and the rotating shaft. The purpose is to do.

  In order to achieve the above object, the present invention includes a housing through which a rotating shaft for transmitting steering torque is inserted, and a sensor sleeve attached to the outer peripheral surface of the rotating shaft, and detects the steering torque of the rotating shaft. A torque sensor; and a seal member disposed between the outer peripheral surface of the sensor sleeve and the inner peripheral surface of the housing, and the housing is positioned on the torque input side in the axial direction with respect to the seal member. A vertical surface perpendicular to the axial direction, and the seal member is press-fitted into the outer peripheral surface of the sensor sleeve and protrudes radially outward from the main body portion, pressing the sensor sleeve from the outside, A first lip portion that contacts the inner peripheral surface of the housing, and a second lip portion that protrudes from the main body portion toward the axial torque input side and contacts the vertical surface of the housing. It is a power steering apparatus.

  According to the present invention, since the seal member has the first lip portion that contacts the inner peripheral surface of the housing and the second lip portion that contacts the vertical surface of the housing, the seal member temporarily moves in the axial direction. Also, the sealing performance against foreign matters is secured, and the sealing performance of the sealing member can be improved. Further, since the first lip portion is in contact with the inner peripheral surface of the housing, the sensor sleeve is pressed to the rotating shaft side by the seal member, and the fixing force of the sensor sleeve to the rotating shaft can be improved.

  The sensor sleeve is fixed to the outer peripheral surface of the rotating shaft by caulking, and the seal member protrudes from the main body portion, is on the torque input side of the caulking portion of the sensor sleeve, and is on the outer peripheral surface of the rotating shaft. You may further have the 3rd lip | rip part which contact | abuts. In such a case, foreign matter can be prevented from entering the caulking portion side of the sensor sleeve, and the sealing performance of the seal member can be further improved.

  The main body portion of the seal member may extend to the torque output side in the axial direction from the first lip portion. In this case, since the area where the main body portion of the seal member presses the sensor sleeve from the outside increases, the fixing force of the sensor sleeve can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, the fixing force with respect to the rotating shaft of a sensor sleeve can be improved, improving the sealing performance of the sealing member between a housing and a rotating shaft.

It is a figure which shows the outline of a structure of a power steering apparatus. It is explanatory drawing of the partial cross section which shows the structure of the electric assist mechanism periphery of a power steering apparatus. It is explanatory drawing of the longitudinal cross-section which shows the structure in a gear housing. It is explanatory drawing which shows the shape of a torque sensor, a rotating shaft, and a sealing member. It is an enlarged view around a seal member. It is an enlarged view which shows the other shape of a sealing member. It is an enlarged view which shows the other shape of a sealing member. It is explanatory drawing at the time of arrange | positioning a seal member to the torque input side from a sensor sleeve. It is explanatory drawing which shows the other structural example of a gear housing and an input shaft.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  FIG. 1 shows an example of a power steering apparatus 1 according to the present embodiment.

  The power steering device 1 includes, for example, a rotary shaft 10 including a steering shaft that transmits a steering torque applied by a steering wheel H, an electric assist mechanism 12 that applies an auxiliary steering torque to the rotary shaft 10 by an electric motor 11, An intermediate shaft 13 connected to the output side of the rotary shaft 10 to which auxiliary steering torque is applied, a tie rod 14 for steering the wheel, a rack and pinion type steering gear 15 for transmitting the steering force of the intermediate shaft 13 to the tie rod 14, etc. have.

  As shown in FIG. 2, the rotating shaft 10 passes through the housing 20. The rotary shaft 10 is connected to, for example, a steering shaft 21 connected to the steering wheel H, an input shaft 22 that is connected to the steering shaft 21 and inputs steering torque to the electric assist mechanism 12, and the input shaft 22 and the intermediate shaft 13. It is connected to an output shaft 23 that is connected and outputs an auxiliary steering torque by the electric assist mechanism 12. The housing 20 is divided into, for example, columns 30 and 31 and a gear housing 32 corresponding to the steering shaft 21, the input shaft 22, and the output shaft 23 of the rotating shaft 10. A connecting portion between the input shaft 22 and the output shaft 23 is disposed on the gear housing 32 side. Note that the position and number of divisions of the rotary shaft 10 and the housing 20 can be arbitrarily selected. Hereinafter, in the present embodiment, the input shaft 22 side (right side in FIG. 2) of the rotary shaft 10 is referred to as a torque input side, and the output shaft 23 side (left side in FIG. 2) is referred to as a torque output side.

  As shown in FIGS. 2 to 4, the torque output side end 22 a of the input shaft 22 is formed in a cylindrical shape with an increased diameter, and the tip of the torque input side end 23 a of the output shaft 23 is reduced in diameter. ing. An end 23 a of the output shaft 23 is fitted inside the end 22 a of the input shaft 22. Further, a groove 22b is formed on the outer peripheral surface of the end 22a of the input shaft 22 in which a caulking portion 84 of a sensor sleeve 80 described later is caulked. On the outer peripheral surface of the end portion 23a of the output shaft 23, a groove 23b for torque detection by a torque sensor 70 described later is formed.

  An elastic torsion bar 50 is fitted in the axial hole 23 c of the output shaft 23. An end 50 a on the torque input side of the torsion bar 50 protrudes from the output shaft 23, and is fitted into the input shaft 22 in the hole 22 c of the shaft core. Thus, when a steering torque is applied from the steering column H to the input shaft 22, the torsion bar 50 is twisted according to the magnitude of the steering torque, and the input shaft 22 rotates relative to the output shaft 23.

  The columns 30 and 31 shown in FIG. 2 are fitted into each other and have a telescopic structure that allows the entire length in the axial direction to be expanded and contracted. A clamp device 40 is provided between the columns 30 and 31 to fix the relative positions in the axial direction. The end of the column 31 on the torque output side is fitted into the outer periphery of the gear housing 32 from the outside.

  As shown in FIGS. 2 and 3, the gear housing 32 supports the output shaft 23 via two bearings 60 and 61 arranged in the axial direction. A worm gear 62 as a speed reduction mechanism is provided between the bearings 60 and 61, and the output of the electric motor 11 of the electric assist mechanism 12 is decelerated by the worm gear 62 and applied to the output shaft 23 as an auxiliary steering torque.

  A torque sensor 70 is provided on the torque input side of the bearings 60 and 61 in the gear housing 32. The torque sensor 70 is, for example, a rotary non-contact torque sensor. The torque sensor 70 is a cylindrical sensor sleeve 80 disposed around the output shaft 23, and is disposed outside the sensor sleeve 80. The torque sensor 70 has a current corresponding to the deformation of the torsion bar 50. , A cover 82 surrounding the coil 81, a circuit board 83 for detecting the current of the coil 81, and the like. The sensor sleeve 80 extends from the outer periphery of the end portion 23 a of the output shaft 23 to the outer periphery of the end portion 22 a of the input shaft 22. The tip of the sensor sleeve 80 on the torque input side is a caulking portion 84 and is caulked in the groove 22b of the input shaft 22, whereby the sensor sleeve 80 is fixed to the outer peripheral surface of the input shaft 22. The sensor sleeve 80 is formed with a window 85 corresponding to the torque detecting groove 23b.

  As shown in FIG. 5, on the torque input side of the torque sensor 70 in the gear housing 32, there are an inner peripheral surface 32a that forms a space for accommodating a seal member 90 described later, and a torque input side of the inner peripheral surface 32a. A vertical surface 32b perpendicular to the direction is formed. On the torque input side with respect to the vertical surface 32 b, the diameter gradually decreases corresponding to the outer shape of the end portion 22 a of the input shaft 22.

  A ring-shaped seal member 90 having elasticity is provided outside the sensor sleeve 80. The seal member 90 is configured by coating a resin around an annular cored bar 90a. The cross section of the cored bar 90a has an L shape in which the inside of the seal member 90 extends in the axial direction and the end on the torque input side is bent radially outward. The seal member 90 is press-fitted into the outer peripheral surface of the sensor sleeve 80 using the strength of the cored bar 90a. The seal member 90 includes a cylindrical main body portion 100 that presses the sensor sleeve 80 from the outside, and an annular first lip portion 101 that protrudes radially outward from the main body portion 100 and contacts the inner peripheral surface 32 a of the gear housing 32. The annular second lip portion 102 protrudes from the main body portion 100 toward the axial torque input side and contacts the vertical surface 32b of the gear housing 32. The main body 100 of the seal member 90 presses the caulking portion 84 of the sensor sleeve 80 from the outside. The first lip portion 101 and the second lip portion 102 are pressed against the inner peripheral surface 32a and the vertical surface 32b, respectively, with a predetermined force. Thereby, when a foreign substance enters the gear housing 32 from the torque input side, the entry of the foreign substance is prevented by the seal member 90, and the foreign substance can be prevented from coming into contact with the torque sensor 70. In addition, since the 2nd lip | rip part 102 has opposed the surface of the metal core 90a, it has become difficult to stick and can maintain sufficient pressing force with respect to each pressing part.

  According to the present embodiment, the seal member 90 has the first lip portion 101 that contacts the inner peripheral surface 32 a of the gear housing 32 and the second lip portion 102 that contacts the vertical surface 32 b of the gear housing 32. Even if the sealing member 90 moves in the axial direction, the sealing performance against foreign matters is secured, and the sealing performance of the sealing member 90 can be improved. Further, since the first lip portion 101 is in contact with the inner peripheral surface 32a of the gear housing 32, the sensor sleeve 80 is pressed against the input shaft 22 by the seal member 90, and the fixing force of the sensor sleeve 80 to the input shaft 22 is increased. Can be improved. Further, since the sensor sleeve 80 is tightened from the outside by the cored bar 90a of the seal member 90, the fixing force of the sensor sleeve 80 to the input shaft 22 can be further improved.

  In the above embodiment, the seal member 90 protrudes from the main body portion 100 as shown in FIG. 6 and is a third lip that contacts the outer peripheral surface of the input shaft 22 on the torque input side of the caulking portion 84 of the sensor sleeve 80. The unit 110 may be further included. In such a case, foreign matter can be prevented from entering the caulking portion 84 side of the sensor sleeve 80, and the sealing performance of the seal member 90 can be further improved.

  As shown in FIG. 7, the main body portion 100 of the seal member 90 may extend to the torque output side in the axial direction from the first lip portion 101. In this case, since the area where the main body 100 of the seal member 90 presses the sensor sleeve 80 from the outside increases, the fixing force of the sensor sleeve 80 to the input shaft 22 can be further improved.

  Incidentally, for example, as shown in FIG. 8, when the seal member 90 is provided on the torque input side from the sensor sleeve 80, a space 120 for the seal member 90 is separately provided between the input shaft 22 and the gear housing 32. There is a need. In the present embodiment, since the seal member 90 is provided on the outer peripheral surface of the sensor sleeve 80, it is not necessary to separately provide a space for the seal member. Specifically, as shown in FIG. 9, it is possible to simplify the shapes of the end 22a of the input shaft 22 and the inner peripheral surface of the gear housing 32 without providing an extra space on the torque input side than the sensor sleeve 80. it can. Further, the input shaft 22 can be shortened by the amount that does not require the space 120, and the power steering device 1 as a whole can be downsized.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

DESCRIPTION OF SYMBOLS 1 Power steering apparatus 10 Rotating shaft 20 Housing 22 Input shaft 23 Output shaft 32 Gear housing 32a Inner peripheral surface 32b Vertical surface 70 Torque sensor 80 Sensor sleeve 90 Seal member 100 Main body portion 101 First lip portion 102 Second lip portion

Claims (3)

A housing through which a rotating shaft for transmitting steering torque is inserted;
A torque sensor that has a sensor sleeve attached to an outer peripheral surface of the rotating shaft and detects a steering torque of the rotating shaft;
A seal member disposed between an outer peripheral surface of the sensor sleeve and an inner peripheral surface of the housing;
The housing has a vertical surface that is positioned on an axial torque input side with respect to the seal member and is perpendicular to the axial direction;
The seal member is press-fitted into the outer peripheral surface of the sensor sleeve, and a main body portion that presses the sensor sleeve from the outside, and a first lip portion that protrudes radially outward from the main body portion and contacts the inner peripheral surface of the housing And a second lip portion protruding from the main body portion toward the axial torque input side and abutting against a vertical surface of the housing. The sensor sleeve is fixed to the outer peripheral surface of the rotating shaft by caulking,
2. The power steering according to claim 1, wherein the seal member further includes a third lip portion that protrudes from the main body portion and is in a torque input side of the caulking portion of the sensor sleeve and abuts against an outer peripheral surface of the rotating shaft. apparatus.   3. The power steering device according to claim 1, wherein a main body portion of the seal member extends to a torque output side in an axial direction from the first lip portion.

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