Steering device

Abstract

To provide a steering device having a simple configuration and little rattle.SOLUTION: A steering device S comprises: a housing 1 having an opening 12 in a cylindrical wall part; a column C with one end to which a handle H is attached and the other end inserted into the housing 1, which expands and contracts with respect to the housing 1; a case part 2 provided on the column C and protruding from the opening 12; a nut 3 included in the case part 2 and having a female thread part 3a; a motor M provided in the housing 1; and a male screw member 4 which transmits the rotation of the motor M to the nut 3 via the female thread part 3a and causes the column C to expand and contract via the nut 3 and the case part 2. The inside of the case part 2 is provided with a biasing member 9 which presses the nut 3 against the column C, and a first receiving surface F1 which is inclined with respect to the pressing direction of the biasing member 9 and against which the nut 3 is pressed, and a second receiving surface F2 which restricts movement of the nut 3 perpendicular to the pressing direction when the nut 3 moves along the first receiving surface F1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The steering device of the present invention relates to a device that adjusts the position of a steering wheel attached to a column by extending and contracting a column via a nut that reciprocates by being driven by a motor. [Background technology]

[0002] Conventionally, such a steering device is disclosed in, for example, Patent Document 1 (see

[0007] to

[0012] and Figs. 1 to 3).

[0003] This steering device uses a drive mechanism to operate a movable column 20 to adjust the front-rear and up-down positions of the steering handle. In particular, this technology is equipped with a rattle prevention mechanism as described below to suppress rattle when adjusting the up-down position of the movable column 20.

[0004] A motor is provided in the housing 10, and a screw shaft 62 that is rotationally driven by the motor and a nut 50 that is screwed onto the screw shaft 62 and moves in the axial direction are provided. The tilt position of the movable column 20 is changed by driving the screw shaft 62.

[0005] The nut 50 is fitted with a pressing member 70 that presses the side surface of the screw shaft 62 that is screwed into it, and is provided with a biasing member 80 that biases the pressing member 70 toward the axis of the screw shaft 62. The biasing member 80 has four legs made of an elastic member, and by embracing the nut 50, the top plate portion approaches the nut 50 based on the elastic force of the legs. At this time, the top plate portion presses the pressing member 70 against the screw shaft 62, eliminating any rattling between the nut 50 and the screw shaft 62.

[0006] According to this technology, the biasing member 80 and other components can be easily assembled, and rattle between the screw shaft 62 and the nut 50 can be prevented with a small number of parts, making it possible to provide an inexpensive device. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-86732 A Summary of the Invention [Problem to be solved by the invention]

[0008] In the above-mentioned conventional steering device, rattle caused by adjustment of the vertical position of the movable column 20 is eliminated. Specifically, a link frame 42 is rotatably supported relative to a housing 10 that holds the movable column 20, and a nut 50 is further rotatably held by this link frame 42. As the nut reciprocates, each of the rotation support parts rotates, and the angle of the movable column 20 is changed.

[0009] Generally, the structure of the rotation support portion has little wobble during operation as long as it has normal machining precision. Therefore, by pressing the nut 50 against the screw shaft 62 as described above, the wobble of the screwed portion is eliminated, and the wobble of the tilt adjustment portion is also eliminated.

[0010] However, this prior art does not include a mechanism for absorbing rattle in the extension / contraction direction of the movable column 20. This technology does not provide a detailed explanation of the mechanism related to the extension / contraction, but includes a general extension / contraction mechanism as shown in Figure 1. That is, it describes another screw shaft driven by a motor, a second nut screwed onto this screw shaft, and a case that houses the nut.

[0011] In the telescopic mechanism of this configuration, when the second nut reciprocates, a gap between the second nut and the wall of the case that houses it is likely to cause rattling. This part is different from the contact position between the screw shaft and the nut where the biasing member 80 functions, so the rattling cannot be eliminated even by using the conventional technology.

[0012] Thus, conventional steering devices still have problems to be solved, and there has been a demand for a high-quality steering device that is simply configured yet eliminates rattling of the steering wheel. [Means for solving the problem]

[0013] (Features) The steering device according to the present invention has the following characteristic configuration: a housing having an opening in a cylindrical wall portion and fixed to a part of a vehicle body; a column having one end to which a steering handle is attached and the other end inserted into the housing and adapted to extend and retract relative to the housing; A case portion provided on a surface of the column and protruding from the opening; A nut having a female thread portion and housed in the case portion; A motor provided in the housing; a male screw member that transmits the rotation of the motor input from one end to the nut via the female screw portion and causes the column to extend and retract via the nut and the case portion, A biasing member that presses the nut toward the column is provided inside the case portion, and a first receiving surface that is inclined with respect to the pressing direction of the biasing member and against which the nut is pressed, and a second receiving surface that restricts movement of the nut perpendicular to the pressing direction when the nut moves along the first receiving surface are provided.

[0014] (effect) This configuration is a steering device that transmits the driving force of a motor to a column via a male screw member, a nut, and a case, and causes the column to extend and retract. This configuration focuses on the assembly part between the nut and the case, and aims to eliminate rattling between the two.

[0015] By pressing the nut against the first contact surface of the case part with the biasing member, the gap between the nut and the case part along the pressing direction of the biasing member can be closed. The nut moves along the first contact surface, but at that time, the component of movement in the direction perpendicular to the pressing direction is restricted by the second contact surface.

[0016] As a result, the nut and the case are positioned in two different directions, eliminating any rattle that exists between them. When the motor is driven in this state, the rotational drive of the male screw member is transmitted extremely smoothly to the column. In this way, a high-quality steering device that eliminates rattle in the steering wheel can be obtained, even with a simple structure that only requires devising the shapes of the nut and the case and providing a biasing member between them.

[0017] (Features) In the steering device of the present invention, it is preferable that a bearing portion that rotatably supports one end of the male screw member is provided on the housing, and that the bearing portion is attached to the housing via a pivot portion so that the other end of the male screw member can move closer to and away from the axis of the column.

[0018] (effect) When the nut is pushed by the biasing member to move to a stable position, the other end of the male screw member screwed into the nut also tries to approach the axis of the male screw member. Although the distance the nut moves due to the pressure of the biasing member is approximately constant, this pressure causes the male screw member to swing around the bearing portion as a fulcrum. The swing angle of this male screw member varies depending on the distance from the bearing portion to the nut. In particular, the closer the nut is to the bearing portion, the larger the swing angle becomes. In addition, even if there is an error in the installation position of the bearing portion or the mounting state of the case portion relative to the column, and the installation posture of the male screw member is not parallel to the axis of the column from the beginning, the male screw member will swing as the nut reciprocates.

[0019] In this configuration, the bearing is attached to the housing via a pivot to allow this swinging motion. This allows the male screw member and the bearing to swing together. This makes it difficult for twisting or the like to occur between the female screw portion of the nut and the male screw member in response to positional fluctuations of the nut relative to the case, and prevents an excessive increase in friction between the two. This allows for smooth position adjustment of the steering handle.

[0020] (Features) In the steering device of the present invention, it is advantageous that the case portion has a cylindrical inner surface, the second receiving surface utilizes a part of the inner surface, and the first receiving surface is a bottom surface provided in a state where it intersects with the cylindrical inner surface.

[0021] (effect) In this way, by providing the case with a cylindrical inner surface, the first and second receiving surfaces can be easily configured. With a cylindrical inner surface, locations that can become the second receiving surface are set all around the circumference in the pressing direction. By determining a single bottom surface that is inclined with respect to the pressing direction as the first receiving surface, the nut moving along the first receiving surface abuts against any location on the cylindrical inner surface, and a single second receiving surface can be reliably determined.

[0022] (Features) In the steering device according to the present invention, it is preferable that a cover member that receives the reaction force of the biasing member is attached to the case portion, and the biasing member is configured integrally with either the cover member or the nut.

[0023] (effect) The biasing member can have various configurations as long as it presses the nut toward the first receiving surface. However, in this configuration, the biasing member is integrally formed with the lid member and the nut that receive the reaction force. This simplifies the component configuration and reduces the number of assembly steps, resulting in a more rational steering device. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view showing a configuration of a steering device according to a first embodiment; [Diagram 2] FIG. 1 is a plan view showing a main structure of a steering device according to a first embodiment; [Diagram 3] FIG. 1 is a side cross-sectional view showing a main structure of a nut and a case portion according to a first embodiment; [Figure 4] FIG. 1 is a cross-sectional plan view showing a main structure of a nut and a case according to a first embodiment; [Diagram 5] FIG. 11 is an explanatory diagram showing the structure of a biasing member according to a second embodiment; [Figure 6] FIG. 13 is an explanatory diagram showing the structure of a biasing member according to a third embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] [First embodiment] (overview) An embodiment of a steering device S according to the present invention will be described with reference to the drawings. First, an overview of a steering device S according to a first embodiment is shown in Figs. 1 to 3. In this steering device S, a column C having a steering handle H attached to one end thereof is inserted into a housing 1 fixed to a part of a vehicle body. The column C is supported by bearings 11 provided at a plurality of positions in the housing 1, and can be extended and retracted relative to the housing 1 by being driven by a motor M.

[0026] An opening 12 is formed in a part of the wall of the housing 1, and a case part 2 protruding from this opening 12 is attached to the surface of the column C. A nut 3 is provided inside the case part 2, and a female thread part 3a is formed in the nut 3, into which a male thread member 4 driven by a motor M is screwed. The nut 3 moves back and forth by the forward and reverse driving of the motor M, which causes the column C to expand and contract, thereby adjusting the position of the steering handle H.

[0027] The steering device S of the present invention is designed to smoothly and quickly adjust the position of the steering handle H by devising an appropriate mounting state of the nut 3 relative to the case portion 2, and when the position adjustment is completed, the rattling of the steering handle H is absorbed to provide a high-quality operating feel.

[0028] (Telescopic drive mechanism) The telescopic drive mechanism of the column C is composed of a male screw member 4, a nut 3 and a case portion 2 that convert the drive of the male screw member 4 into telescopic movement of the column C, and a motor M that drives the male screw member 4. Below, these components will be described in order.

[0029] (Male threaded member and motor) As shown in Figures 1 and 2, the male screw member 4 is screwed into the nut 3 near its center, and one end of the male screw member 4 is rotatably supported by a bearing portion 5 provided in the housing 1. The bearing portion 5 is formed integrally with a gear case 6. One end of the male screw member 4 is rotatably supported by the gear case 6 via a bearing of the bearing portion 5. A second gear G2 is provided on the male screw member 4 at a position adjacent to the bearing. A first gear G1 provided on the output shaft Ma of the motor M meshes with this second gear G2.

[0030] A step 41 is formed in the portion of the male screw member 4 that is journalled by the bearing portion 5. This step 41 abuts against a side surface of an inner case 51 of the bearing portion 5, preventing the male screw member 4 from moving closer to the handle H.

[0031] On the other hand, the end 42 of the male screw member 4 has a curved tip and is disposed with a slight gap between it and the wall surface 61 of the gear case 6 adjacent to the bearing portion 5. This prevents the male screw member 4 from moving in a direction away from the handle H.

[0032] 1 and 2, the bearing portion 5 and the gear case 6 are configured to be able to swing relative to the housing 1. Specifically, the gear case 6 is connected to the housing 1 by a pivot portion 7, and the end of the male screw member 4 that is closer to the steering wheel H moves toward and away from the axis X of the column C. With this configuration, as will be described later, unnecessary twisting does not occur between the male screw member 4 and the nut 3 during slight movement of the nut 3 relative to the case portion 2, and the position of the steering wheel H can be smoothly adjusted.

[0033] (Nut and case) The configurations of the nut 3 and case portion 2 in this embodiment are shown in Figures 2 and 3. Here, both have a cylindrical shape, and the nut 3 is inserted into the inside of the case portion 2. The case portion 2 is made of, for example, a metal material, and is fixed to the surface of the column C by a blind rivet 22 or the like as shown in Figure 3. The inner diameter of the case portion 2 is configured to be slightly larger than the outer diameter of the nut 3.

[0034] The nut 3 has a female screw portion 3a formed through its center, into which the male screw member 4 is screwed. The nut 3 reciprocates along the male screw member 4 as the male screw member 4 rotates. The nut 3 is formed in the case portion 2 and is sandwiched between two opposing surfaces perpendicular to the axis X1 of the male screw member 4, and the case portion 2 and the column C reciprocate relative to the housing 1 as the nut 3 reciprocates. In order to prevent the male screw member 4 from interfering with the case portion 2 at that time, a screw insertion hole 21 of a predetermined dimension is formed in the case portion 2.

[0035] As shown in FIG. 3, the nut 3 is fixed in position by the contact between the bottom surface of the case 2 and the peripheral wall surface of the case 2. This bottom surface is particularly referred to as the first receiving surface F1. The first receiving surface F1 is formed in a flat shape and is inclined with respect to the insertion direction of the nut 3. In other words, a normal line perpendicular to the first receiving surface F1 perpendicularly intersects with the axis X1 of the male screw member 4, and the first receiving surface F1 is not perpendicular to the pressing direction of the nut 3. In the example shown in FIG. 3, the upper position of the first receiving surface F1 is closer to the column C, and the lower position is inclined away from the column C. On the other hand, the surface of the outer surface of the nut 3 that is in contact with the first receiving surface F1 is the first contact surface f1. The first contact surface f1 is also flat.

[0036] As shown in Fig. 3, the case part 2 is provided with a cover member 8 that receives the reaction force that presses the nut 3 toward the rear, and a coil spring 9a is disposed between the cover member 8 and the nut 3 as a biasing member 9. The coil spring 9a biases the nut 3 toward the rear, causing the first contact surface f1 to contact the first receiving surface F1 (Fig. 3(a)). After that, the nut 3 slides along the first receiving surface F1.

[0037] However, this sliding distance is small, and part of the cylindrical outer surface of the nut 3 abuts against part of the cylindrical inner surface of the case part 2 (Fig. 3(b)). At this time, the outer surface of the nut 3 is the second abutment surface f2, and the inner surface of the case part 2 is the second receiving surface F2. In this way, the relative movement between the first abutment surface f1 and the first receiving surface F1 generates a movement component in the direction perpendicular to the pushing direction of the nut 3, and the second abutment surface f2 abuts against the second receiving surface F2, fixing the position of the nut 3.

[0038] In this manner, the nut 3 is pressed against the case portion 2, so that the column C is fixed in position relative to the housing 1 without any rattle. This allows the driver to feel less unwanted vibrations from the steering wheel H while driving, and to obtain a steering sensation with a high sense of rigidity.

[0039] When the position of the column C is reversed, the motor M is driven to reverse the direction of movement of the nut 3. If a gap exists between the nut 3 and the case part 2, an idle time occurs in the movement of the column C. Therefore, it is preferable to eliminate the gap between the nut 3 and the case part 2 along the axis X1 of the male screw member 4 as much as possible.

[0040] As in this configuration, by making the outer surface of the nut 3 and the inner surface of the case part 2 cylindrical, the fixed state of the nut 3 is extremely stabilized when the second abutment surface f2 abuts against the second receiving surface F2. In the case of the embodiment of FIG. 3, the movement of the nut 3 along the extension direction of the male screw member 4 is also prevented. Since the second abutment surface f2 and the second receiving surface F2 of the nut 3 and the case part 2 are in line contact with each other at the cylindrical surfaces, if the nut 3 tries to move from this state in the extension direction of the male screw member 4, the nut 3 is forced to move in a direction perpendicular to the male screw member 4 due to the abutment of the cylindrical surfaces. However, this means that the nut 3 moves against the biasing force of the coil spring 9a, and the position of the nut 3 is fixed by being pressed by the biasing force of the coil spring 9a.

[0041] In this way, the nut 3 and the case part 2 have cylindrical surfaces, so that the first receiving surface F1, the first contact surface f1, the second receiving surface F2, and the second contact surface f2 can be easily configured. The first receiving surface F1 and the first contact surface f1 only need to determine one plane that is inclined with respect to the pressing direction. This determines the sliding direction of the nut 3. Accordingly, the second contact surface f2 of the nut 3 is determined, and the second receiving surface F2 is necessarily set on the inner surface of the case part 2. In this way, it is generally easy to make the nut 3 and the case part 2 cylindrical. With this configuration, a stable fixed state of the nut 3 can be obtained, so that a very rational steering device S can be obtained.

[0042] (urging member) When a coil spring 9a is used as the biasing member 9, there is a high degree of freedom in setting the spring constant or the winding diameter and number of turns, and it can be applied to nuts 3 and case parts 2 having various shapes.

[0043] 3, the reaction force of the coil spring 9a is borne by the cover member 8 attached to the case part 2. If the cover member 8 has a screw-fitting shape, for example, the pressing force of the coil spring 9a can be easily adjusted by changing the degree of screwing.

[0044] The effect of the biasing member 9 is that the first abutment surface f1 of the nut 3 and the first receiving surface F1 of the case portion 2 slide relative to each other, causing the second abutment surface f2 of the nut 3 to abut against the second receiving surface F2 of the case portion 2, eliminating rattling of the nut 3. Therefore, the degree of inclination of the first abutment surface f1 and the first receiving surface F1 needs to be set according to the magnitude of the biasing force of the biasing member 9. The stronger the pressing force of the biasing member 9, the more the abutment force between the second abutment surface f2 and the second receiving surface F2 can be secured even if the inclination angle of the first abutment surface f1 and the first receiving surface F1 is reduced.

[0045] By using the biasing member 9 in this manner, for example, when the male screw member 4 is driven to rotate, the rotation of the nut 3 is well restricted by the inner surface of the case portion 2. Therefore, when the male screw member 4 starts to rotate, the nut 3 immediately starts to reciprocate, enabling quick position adjustment of the steering handle H. Also, rattling of the column C is rationally prevented, and a compact steering device S can be obtained.

[0046] (Effect of pivot) When the nut 3 is pushed by the biasing member 9 to move to a stable position, the other end of the male screw member 4 screwed into the nut 3 also tries to approach the axis X of the column C. Although the moving distance of the nut 3 due to the pressing force of the biasing member 9 is approximately constant, the male screw member 4 swings around the bearing portion 5 as a fulcrum during this pressing force. The swing angle of the male screw member 4 varies depending on the distance from the bearing portion 5 to the nut 3. In particular, the closer the nut 3 is to the bearing portion 5, the larger the swing angle becomes. In addition, even if there is an error in the installation position of the bearing portion 5 or the mounting state of the case portion 2 relative to the column C, and the installation posture of the male screw member 4 is not parallel to the axis X of the column C from the beginning, the male screw member 4 swings with the reciprocating movement of the nut 3.

[0047] In this configuration, to allow this swinging, the bearing portion 5 is attached to the housing 1 via a pivot portion 7. This allows the male screw member 4 and the bearing portion 5 to swing together. This makes it difficult for twisting or the like to occur between the female screw portion 3a of the nut 3 and the male screw member 4 in response to positional fluctuations of the nut 3 relative to the case portion 2, and prevents an excessive increase in frictional force between them. This allows for smooth position adjustment of the steering handle H.

[0048] When the male screw member 4 is made oscillating, it is advisable to configure the outer surface of the nut 3 so that it can change position smoothly relative to the inner surface of the case portion 2. For example, Fig. 4 is a plan sectional view of the nut 3 and the case portion 2, and the side surface 31 of the nut 3 is configured to be spindle-shaped. The width of the portion where the female screw portion 3a is formed is formed to be equal to the width between the inner surfaces of the case portion 2, and the width is narrower in the vicinity of the first contact surface f1 and in the vicinity of the surface pressed by the biasing member 9.

[0049] With this configuration, even if the male screw member 4 swings, the width along the axis X1 of the male screw member 4 is narrowed on the front side of the nut 3 and near the first abutment surface f1 along the pressing direction of the nut 3. Therefore, no unnecessary twisting or the like occurs between the male screw member 4 and the case part 2 when the nut 3 is operated.

[0050] (Relationship between the biasing member and the inclination of the first receiving surface) The effect of the biasing member 9 is that the first contact surface f1 of the nut 3 and the first receiving surface F1 of the case part 2 slide relative to each other, causing the second contact surface f2 of the nut 3 to contact the second receiving surface F2 of the case part 2, thereby eliminating rattling of the nut 3. Therefore, the degree of inclination of the first contact surface f1 and the first receiving surface F1 needs to be set according to the magnitude of the biasing force of the biasing member 9.

[0051] The stronger the pressing force of the biasing member 9, the smaller the inclination angle of the first contact surface f1 and the first receiving surface F1 can be, but the sufficient contact force between the second contact surface f2 and the second receiving surface F2 can be ensured.

[0052] Second Embodiment 5 shows a second embodiment of the biasing member 9. Here, the biasing member 9 is made of a leaf spring, and is integrally formed with the cover member 8 that receives the reaction force. The cover member 8 is made of, for example, a metal drawn part in a cup shape, and is configured to be able to fit or screw into the case part 2. A part of the end face is cut out to process the bent part 9b, which is configured to press the end face of the nut 3. The material can be various metals, as well as resin materials.

[0053] With this configuration, a predetermined pressing force can be applied to the nut 3 simply by attaching the cover member 8 to the case portion 2. In addition, since the cover member 8 and the biasing member 9 are integrated, the number of parts is reduced, the labor required for parts management and the number of assembly steps are reduced, and the steering device S can be configured rationally.

[0054] Third Embodiment FIG. 6 shows a third embodiment of the urging member 9. Here, the urging member 9 is integrally formed with the nut 3. The nut 3 is made of, for example, a metal material, and the urging member 9 is two-color molded with a resin material on the back surface of the nut 3. For example, a plurality of columnar resin protrusions 9c are formed, and when the cover member 8 is attached to the case part 2, the resin protrusions 9c are pressed by the cover member 8 and elastically deformed. Alternatively, the nut 3 and the urging member 9 can be made of the same resin material.

[0055] In the case of this configuration, the nut 3 is pushed to the rear side by a predetermined pressing force simply by attaching the cover member 8 to the case part 2. In addition, it is possible to reduce the number of parts, the labor required for parts management, and the number of assembly steps, thereby enabling the rationalization of the steering device S. [Industrial Applicability]

[0056] The steering device of the present invention can be widely used as a device for adjusting the position of a steering wheel attached to a column by extending and contracting a column via a nut that reciprocates by being driven by a motor. [Explanation of symbols]

[0057] 1. Housing 2 Case part 3 Nut 3a Female thread 4 Male threaded member 5 Bearing section 7 Cardinal Branch 8 Lid member 9. Pressing member 9a Leaf spring 12 Opening C Column F1 First Abutment F2 Second receiving surface H. Steering handle Medium motor S Steering device X-axis center

Claims

1. a housing having an opening in a cylindrical wall portion and fixed to a part of a vehicle body; a column having one end to which a steering handle is attached and the other end inserted into the housing and adapted to extend and retract relative to the housing; A case portion provided on a surface of the column and protruding from the opening; A nut having a female thread portion and housed in the case portion; A motor provided in the housing; a male screw member that transmits the rotation of the motor input from one end to the nut via the female screw portion and causes the column to extend and retract via the nut and the case portion, A steering device in which a biasing member that presses the nut toward the column is provided inside the case portion, and a first receiving surface that is inclined with respect to the pressing direction of the biasing member and against which the nut is pressed, and a second receiving surface that restricts movement of the nut perpendicular to the pressing direction when the nut moves along the first receiving surface.

2. 2. The steering device according to claim 1, wherein a bearing portion that rotatably supports one end of the male screw member is provided on the housing, and the bearing portion is attached to the housing via a pivot portion so that the other end of the male screw member can move toward and away from the axis of the column.

3. 3. The steering device according to claim 1, wherein the case portion has a cylindrical inner surface, the second receiving surface utilizes a portion of the inner surface, and the first receiving surface is a bottom surface provided in a state in which it intersects with the cylindrical inner surface.

4. 3. A steering apparatus according to claim 1, wherein a cover member that receives a reaction force of the biasing member is attached to the case portion, and the biasing member is integrally formed with either the cover member or the nut.

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