Steering wheel

Abstract

To prevent increase in manufacturing processes and costs in a steering wheel having a holding detection function.SOLUTION: A steering wheel 1 of the disclosure includes: a center member 1B rotatably connected to a vehicle; and a holding member 1A which is connected to the center member, disposed enclosing the outer side of the center member, and has a substantially annular shape. The holding member 1A includes: a core grid member 10 which is provided in the holding member and formed by a conductor formed in an annular shape; and a cover member 40 which encloses a periphery of the core grid and is made of an insulator. Further, the steering wheel 1 includes a detection circuit which is electrically connected to the core grid member 10 and detects electrostatic capacity which may occur in the core grid member 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to steering wheels. [Background technology]

[0002] As described in Patent Document 1, a steering wheel mounted on a vehicle may be equipped with a configuration for detecting the driver's grip. In Patent Document 1, a sensor electrode (36) is arranged on the annular rim portion (12) constituting the steering wheel (10), and the driver's grip of the rim portion (12) is detected by detecting the electrostatic capacitance generated in the sensor electrode (35). Here, the configuration described in Patent Document 1 will be described with reference to the reference numerals given to the drawings in Patent Document 1.

[0003] First, the steering wheel (10) has an annular rim portion (12) that has a substantially circular cross section in a direction (R) substantially perpendicular to the circumferential direction (L), and a metal core (18) is disposed near the center of the rim portion (12). In Patent Document 1, an insulator (26) such as urethane, a shield (42), an insulator (40), a sensor electrode (36), and a leather layer (32) are disposed in this order from the center toward the outer periphery inside the rim portion (12) having a substantially circular cross section, so as to surround the periphery of the metal core (18). In Patent Document 1, the shield (42) thereby suppresses capacitive coupling between the metal core (18) and the sensor electrode (36), thereby improving the detection accuracy of the electrostatic capacitance generated in the sensor electrode (36) when the driver grips the rim portion (12). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6992951 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 mentioned above can cause problems such as increased manufacturing labor and costs due to the complex structure of the rim of the steering wheel, the labor required to attach the sensor electrode to the rim, and the sensor electrode peeling off or warping from the rim due to molding pressure that can occur when resin molding the steering wheel using a urethane material or the like.

[0006] Therefore, one of the objects of the present disclosure is to solve the problem of increased manufacturing man-hours and costs due to the complex structure of steering wheels having a function of detecting when the steering wheel is gripped by a driver. [Means for solving the problem]

[0007] A steering wheel according to one embodiment of the present disclosure includes: a central member rotatably coupled to the vehicle; A generally annular gripping member connected to the central member and arranged to surround the outside of the central member; Equipped with the gripping member includes a core metal member made of a conductor provided inside the gripping member and formed in a ring shape, and a covering member made of an insulator surrounding the core metal member, Further, a detection circuit is provided which is electrically connected to the core metal member and detects electrostatic capacitance which may occur in the core metal member. The structure is as follows. Effect of the Invention

[0008] As configured as described above, the present disclosure makes it possible to simplify the structure of a steering wheel having a function of detecting whether it is being gripped by a driver, and to reduce manufacturing man-hours and costs. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an outline of the configuration of a steering wheel according to the present disclosure; [Diagram 2]1 is a cross-sectional view showing a configuration of a rim portion of a steering wheel according to the present disclosure. [Diagram 3] 1 is a diagram showing a configuration of a core metal of a steering wheel according to the present disclosure. [Figure 4] 1A and 1B are diagrams illustrating a configuration of a steering wheel shield according to the present disclosure. [Diagram 5] FIG. 2 is a diagram showing a state in which the steering wheel according to the present disclosure is assembled. [Figure 6] FIG. 2 is a diagram showing a state in which the steering wheel according to the present disclosure is assembled. [Figure 7] FIG. 2 is a diagram showing the configuration of a harness for a steering wheel according to the present disclosure. [Figure 8] FIG. 2 is a diagram showing a state in which the steering wheel according to the present disclosure is assembled. [Figure 9] FIG. 2 is a diagram showing a circuit configuration of a steering wheel according to the present disclosure. [Figure 10] FIG. 13 is a diagram showing another configuration of the circuit of the steering wheel according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Embodiment 1> The present disclosure will be described with reference to the drawings.

[0011] As shown in Fig. 1 (1-1), the steering wheel 1 in this embodiment is mounted on a vehicle and is gripped and operated by a driver P of the vehicle. As shown in Fig. 1 (1-2), the steering wheel 1 includes spoke portions 1B (central member) rotatably connected to the vehicle, and a substantially annular rim portion 1A (grip member) connected to the spoke portions 1B and arranged to surround the outside of the spoke portions 1B. The steering wheel 1 in this embodiment further includes a configuration for detecting the grip of the rim portion 1A by the driver P.

[0012] The specific configuration of the steering wheel 1 will be described below, but the shape and configuration of the steering wheel 1 are not necessarily limited to those described below. For example, the shape of the rim portion 1A of the steering wheel 1 will be described below as being annular, but it may be annular with an outer shape other than a circle, and accordingly, each member constituting the rim portion 1A is not limited to being annular.

[0013] FIG. 2 shows a cross-sectional view taken along line AA in FIG. 1(1-2). Here, FIG. 2(2-1) shows only the rim portion 1A of the steering wheel 1, and FIG. 2(2-2) also shows the hand (fingers) of the driver P gripping the rim portion 1A. The cross-sectional view taken along line AA shows a cross-section in a direction approximately perpendicular to the circumferential direction of the annular rim portion 1A. In other words, the cross-sectional view taken along line AA shows a radial cross-section of the annular rim portion 1A. Therefore, each member shown in the cross-section shown in FIG. 2 is a member that is uniformly formed along the circumferential direction of the annular rim portion 1A.

[0014] A metal core 10 (core member) made of metal having a predetermined rigidity is disposed near the center of the rim portion 1A of the steering wheel 1 in the cross section shown in Fig. 2 (2-1). The outer shape of the core 10 is formed as shown in Fig. 3, and includes a rim core portion 11 formed in an annular shape and disposed inside the rim portion 1A, and spoke core portions 12 located at predetermined diameter positions of the rim core portion 11 corresponding to the spoke portions 1B. In other words, the core portion 10 forms the framework of the steering wheel 1, and the spoke core portions 12 near the center corresponding to the spoke portions 1B are rotatably connected to the vehicle, and the annular rim core portion 11 is disposed by being connected to both ends of the spoke core portions 12.

[0015] The core metal 10 is made of a conductor, and as described below, the rim core metal portion 11 in particular functions as an electrode that generates a capacitance to be detected by the detection circuit. The rim core metal portion 11 is electrically connected to detection connections 13 formed on the spoke core metal portions 12, and the capacitance of the rim core metal portion 11 is detected from these detection connections 13. However, the spoke core metal portions 12 are insulated at the connection points with the vehicle near the center, and are not electrically connected to ground on the vehicle side.

[0016] The electrical connections in the detection connection part 13 shown in the present application, the shield connection part 23 described later, the first connection part 51a and the second connection part 52a are shown as examples of electrical connections made by contact between conductive members, but are not limited to this and may be connections made by a harness or the like having an electrical connection part.

[0017] As shown in Fig. 2 (2-1), the cross section of the rim core metal portion 11 in the radial direction is formed into a roughly L-shape, and the rim core metal portion 11 is constituted by these roughly L-shaped members being uniformly formed along the circumferential direction of the annular shape. As a result, the rim core metal portion 11 is formed with two annular faces of a given width arranged roughly perpendicular to each other. In this case, one of the two annular faces forming the rim core metal portion 11 is arranged so as to face the inner periphery of the annular rim portion 1A.

[0018] As shown in the cross section of FIG. 2 (2-1), the shield 20 is provided around the rim core metal part 11 arranged near the center of the rim part 1A, covering a part of the rim core metal part 11. The shield 20 has an outer shape as shown in FIG. 4, and is formed in an annular shape so as to be arranged inside the rim part 1A. Specifically, as shown in FIG. 2 (2-1), the cross section of the shield 20 in the radial direction is formed in a substantially L-shape, and the shield 20 is configured by uniformly forming such substantially L-shaped members along the circumferential direction of the annular shape. For this reason, the shield 20 is configured in such a way that two annular faces having a predetermined width are connected in a bent arrangement so as to be substantially perpendicular to each other. At this time, the first shield part 21, which is one of the two annular faces forming the shield 20, is arranged to be located on the outer periphery side with respect to the rim core metal part 11. As a result, the part of the rim core metal part 11 on the outer periphery side of the rim part 1A is uniformly covered by the first shield part 21 along the circumferential direction. Further, the second shield part 22, which is the other of the two annular faces forming the shield 20, is positioned on the rear side of the vehicle, i.e., the driver P side, with respect to the rim core metal part 11. As a result, the part of the rim core metal part 11 on the driver P side, which is the rear side of the vehicle, is covered uniformly along the circumferential direction by the second shield part 22. Note that the first shield part 21 and the second shield part 22 may be formed integrally, or may be formed separately and then electrically connected to each other.

[0019] The second shield portion 22 constituting the above-mentioned shield 20 may be disposed on the vehicle front side with respect to the rim core metal portion 11. In other words, the shield 20 may be formed in a shape that is upside down in the cross section shown in Fig. 2 (2-1), so that the part of the rim core metal portion 11 on the opposite side to the driver P side, which is the vehicle front side, is covered by the second shield portion 22 uniformly along the circumferential direction.

[0020] Thus, in a radial cross section, the shield 20 covers the outer circumferential side of the rim core metal portion 11 and the rear side of the vehicle, and is disposed at a distance from the rim core metal portion 11. And because the shield 20 is made of a conductor, in the direction covered by the shield 20, as described below, it suppresses the generation of an electric field between the rim core metal portion 11 and a detection object such as the finger of the driver P, that is, the generation of electrostatic capacitance.

[0021] As shown in the cross section of FIG. 2 (2-1), an insulating layer 30 made of an insulator such as resin is interposed between the shield 20 and the rim core metal part 11 according to the arrangement of the above-mentioned shield 20. The insulating layer 30 has an outer shape as shown in FIG. 5, and is formed in a ring shape arranged inside the rim part 1A. As shown in FIG. 2 (2-1), the cross section of the insulating layer 30 in the radial direction is formed in a substantially L-shape similar to the above-mentioned shield 20, and the insulating layer 30 is configured by forming such substantially L-shaped members uniformly along the circumferential direction of the ring. For this reason, the insulating layer 30 is configured in such a way that two ring-shaped surfaces having a predetermined width are connected in a bent arrangement so as to be substantially perpendicular to each other. At this time, one of the two ring-shaped surfaces forming the insulating layer 30 is arranged on the outer circumferential side with respect to the rim core metal part 11 in a state where it is stacked with the first shield part 21 of the shield 20. Furthermore, the other of the two annular surfaces forming the insulating layer 30 is arranged in a state where it is laminated with the second shield portion 22 of the shield 20 and is positioned on the rear side of the vehicle with respect to the rim core metal portion 11. In this way, the insulating layer 30 maintains a state where the above-mentioned rim core metal portion 11 and the shield 20 are insulated. The thickness of the insulating layer 30 is formed to be thinner than the thickness of a covering portion 40 that covers the further outside of the shield 20, which will be described later.

[0022] In this embodiment, the insulating layer 30 is formed integrally with the shield 20 to form the shield unit 20, 30. The shield unit 20, 30 is connected to the rim core metal portion 11 of the core metal 10 as shown in FIG. 2. At this time, a fitting hole (connecting portion) is formed in the surface of the rim core metal portion 11 of the core metal 10 located on the vehicle rear side, and a connecting portion 31 that protrudes from the surface on the vehicle front side is formed in the insulating layer 30 corresponding to this. By inserting the connecting portion 31 into the fitting hole of the rim core metal portion 11, the shield unit 20, 30 consisting of the insulating layer 30 and the shield 20 can be connected to the rim core metal portion 11. The state in which the shield unit 20, 30 is connected to the core metal 10 is shown in FIG. 5.

[0023] As shown in FIG. 4, the insulating layer 30 is formed with an extension 32 disposed at the position of the spoke portion 1B of the steering wheel 1. Accordingly, the extension 32 extends from the shield 20 integrally connected as the shield units 20, 30, and a shield connection portion 23 electrically connected to the shield 20 is formed. The shield connection portion 23 functions to connect the shield 20, which is a conductor, to the ground. Then, as shown in FIG. 5, by mounting the shield units 20, 30 to the core bar 10 as described above, the extension 32 of the insulating layer 30 is disposed at a portion of the spoke core bar portion 12 of the core bar 10 different from the portion where the detection connection portion 13 is formed, and the shield connection portion 23 is disposed at such a portion.

[0024] The rim portion 1A of the steering wheel 1 configured as described above is provided with a covering portion 40 (covering member) made of insulating ends such as urethane that surrounds the connected core metal 10, shield 20, and insulating layer 30 and forms the outer shape of the rim portion 1A. As shown in the cross section of FIG. 2 (2-1), the covering portion 40 has a substantially circular outer shape in the radial direction, and is formed with a predetermined thickness from the core metal 10 and shield 20 located near the center of the rim portion 1A to the outer periphery. For example, the covering portion 40 is formed to be thicker than any of the core metal 10, shield 20, and insulating layer 30. FIG. 6 shows the state in which the covering portion 40 is provided on the rim portion 1A of the steering wheel 1.

[0025] 7 is attached to the spoke portion 1B of the steering wheel 1. Although the switch unit 50 is called the switch unit 50 in this embodiment, the switch unit 50 is not limited to an operating device that can be operated by the driver, but may be a control unit that performs electrical communication and includes an ECU (Electronic Control Unit).

[0026] The switch unit 50 includes a first switch section 51 and a second switch section 52, as well as a harness 53 and a connector 54 that connect these sections. A first connection section 51a that is connected to the detection connection section 13 formed on the spoke core section 12 of the core section 10 is formed on the back side of the first switch section 51 shown in the lower diagram of Fig. 7, and a second connection section 52a that is connected to the shield connection section 23 formed on the spoke core section 12 of the core section 10 is formed on the back side of the second switch section 52 shown in the lower diagram of Fig. 7. The state in which the switch unit 50 is attached to the spoke section 1B of the steering wheel 1 is shown in Fig. 8.

[0027] The switch unit 50 described above configures a detection circuit as shown in FIG. 9, for example. First, the first switch section 51 includes a first connection section 51a, a low-pass filter (LPF) 51b, a CPU 51c, a LIN 51d, and a power supply circuit 51e. The second switch section 52 includes a second connection section 52a that is grounded by the first switch section 51. In the detection circuit configured as above, the CPU 51c detects capacitance that may occur from the first connection section 51a to the core bar 10, and notifies the vehicle-side control device of the detected capacitance value via the connector 54. This allows the vehicle-side control device to detect the driver's gripping state according to the notified capacitance value. The CPU 51c may detect the driver's gripping state according to the detected capacitance value. Then, the vehicle-side control device may perform processing such as outputting a warning according to the detected driver's gripping state. The detection circuit may be configured as shown in FIG. 10.

[0028] Furthermore, the above-mentioned switch unit 50 may be configured to detect the capacitance by the above-mentioned CPU 51c and determine whether the hand is being held or not. In other words, the determination can be completed within the switch unit 50 without notifying the control device on the vehicle side.

[0029] Here, in this embodiment, as described above, the outer circumferential side and the rear side of the vehicle of the rim core metal portion 11 are covered with the shield 20, and the inner circumferential side and the vehicle front side are not covered. Therefore, as shown in FIG. 2 (2-2), when the hand, i.e., the fingers, of the driver P gripping the rim portion 1A are positioned on the inner circumferential side or the vehicle front side of the rim portion 1A, an electric field D is generated between the rim core metal portion 11, which serves as an electrode in the self-capacitance method, and the fingers, and electrostatic capacitance is generated, making it possible to detect the gripping state. Note that FIG. 2 (2-2) shows an example of the position of the thumb and index finger, etc., when the driver P grips the rim portion 1A with his or her hand, and an electric field D is generated between the rim core metal portion 11 and each finger.

[0030] On the other hand, the generation of electrostatic capacitance is suppressed between the outer circumferential side of the rim core metal portion 11 covered by the shield 20 and the rear side of the vehicle when the knees, chest, etc. of the driver P may come close to the outer circumferential side of the rim core metal portion 11 and the rear side of the vehicle, or when the driver P is in a gripped state (such as when the driver P holds his / her hands over the steering wheel 1). Specifically, as shown in FIG. 1 (1-1), the thighs, knees, chest, abdomen, etc. of the legs of the driver P may come close to the outer circumferential side of the rim core metal portion 11 and the rear side of the vehicle, but the shield 20 can suppress the generation of an electric field between the rim core metal portion 11 and the human body, that is, the generation of electrostatic capacitance. As a result, it is possible to suppress erroneous detection when the driver P is not gripping the rim portion 1A.

[0031] As described above, even when the second shield portion 22 of the shield 20 is configured to be disposed on the vehicle front side, it is possible to suppress erroneous detection when the rim portion 1A is not gripped by the driver P. For example, as shown in Fig. 1 (1-1), the legs, particularly the thighs and knees, of the driver P may be close to the vehicle front side below the steering wheel 1, but the second shield 22 disposed on the vehicle front side can suppress the generation of an electric field between the rim core metal portion 11 and the human body, that is, the generation of electrostatic capacitance.

[0032] As described above, the steering wheel 1 in this embodiment is configured to detect electrostatic capacitance that may occur in the rim core metal portion 11 by using the rim core metal portion 11 that constitutes the framework of the rim portion 1A as an electrode in a self-capacitance method. Therefore, as shown in Fig. 2 and other figures, the grip of the driver P can be accurately detected with a simple configuration, and the manufacturing process and costs can be reduced. In addition, by arranging the shield 20 on the outer periphery of the rim portion 1A as described above, erroneous detection of the grip state can be suppressed, and accuracy can be improved.

[0033] <Additional Notes> A part or all of the above-described embodiments can be described as follows: The following is an outline of the configuration of a steering wheel according to the present disclosure. However, the present disclosure is not limited to the following configuration. (Appendix 1) a central member rotatably coupled to the vehicle; A generally annular gripping member connected to the central member and arranged to surround the outside of the central member; Equipped with the gripping member includes a core metal member made of a conductor provided inside the gripping member and formed in a ring shape, and a covering member made of an insulator surrounding the core metal member, Further, a detection circuit is provided which is electrically connected to the core metal member and detects electrostatic capacitance which may occur in the core metal member. Steering wheel. (Appendix 2) 2. A steering wheel as claimed in claim 1, The detection circuit is configured to detect electrostatic capacitance that may occur in the core member by using the core member as an electrode in a self-capacitance method. Steering wheel. (Appendix 3) 2. A steering wheel as claimed in claim 1, The gripping member includes a shield made of a conductor, the shield uniformly covering a part of the periphery of the core metal member in a cross section taken in a direction substantially perpendicular to the circumferential direction of the gripping member, the shield being disposed inside the covering member and spaced apart from the core metal member. Steering wheel. (Appendix 4) 4. A steering wheel as claimed in claim 3, The shield has a first shield portion that uniformly covers a portion of the periphery of the core member on the outer circumferential side of the grip member in the cross section of the grip member along a circumferential direction of the core member. Steering wheel. (Appendix 5) 5. A steering wheel as claimed in claim 4, The shield has a second shield portion that uniformly covers a portion of the periphery of the core metal member on the driver's side, which is a rear side of the vehicle, along a circumferential direction of the core metal member in the cross section of the grip member. Steering wheel. (Appendix 6) 6. A steering wheel as claimed in claim 5, The shield is configured such that the first shield portion and the second shield portion are bent and connected to each other in the cross section of the gripping member. Steering wheel. (Appendix 7) 5. A steering wheel as claimed in claim 4, The shield has a second shield portion that uniformly covers a portion of the periphery of the core metal member on the opposite side to the driver's side, which is the front side of the vehicle, along a circumferential direction of the core metal member in the cross section of the grip member. Steering wheel. (Appendix 8) 4. A steering wheel as claimed in claim 3, The gripping member is configured by interposing an insulating layer between the core metal member and the shield. Steering wheel. (Appendix 9) 9. A steering wheel as claimed in claim 8, The shield and the insulating layer are integrally formed, a connecting portion for attaching the insulating layer to the core metal member is provided on the insulating layer and the core metal member, Steering wheel. [Explanation of symbols]

[0034] 1 Steering wheel 1A Rim section 1B Spoke section 10 Core wire 11 Rim core metal 12 Spoke core 13 Detection connection 20 Shield 21 First Shield Section 22 Second shield section 23 Shield connection 30 Insulating layer 31 Connecting part 32 Extension section 40 Covering part 50 Switch unit 51 First switch section 51a First connection part 51b LPF 51c CPU 51d LIN 51e power supply circuit 52 Second switch section 52a Second connection part

Claims

1. a central member rotatably coupled to the vehicle; A generally annular gripping member connected to the central member and arranged to surround the outside of the central member; Equipped with the gripping member includes a core metal member made of a conductor provided inside the gripping member and formed in a ring shape, and a covering member made of an insulator surrounding the core metal member, Further, a detection circuit is provided which is electrically connected to the core metal member and detects electrostatic capacitance which may occur in the core metal member. Steering wheel.

2. 2. A steering wheel according to claim 1, The detection circuit is configured to detect electrostatic capacitance that may occur in the core member by using the core member as an electrode in a self-capacitance method. Steering wheel.

3. 2. A steering wheel according to claim 1, The gripping member includes a shield made of a conductor, the shield uniformly covering a part of the periphery of the core metal member in a cross section taken in a direction substantially perpendicular to the circumferential direction of the gripping member, the shield being disposed inside the covering member and spaced apart from the core metal member. Steering wheel.

4. 4. A steering wheel according to claim 3, The shield has a first shield portion that uniformly covers a portion of the periphery of the core member on the outer circumferential side of the grip member in the cross section of the grip member along a circumferential direction of the core member. Steering wheel.

5. 5. A steering wheel according to claim 4, The shield has a second shield portion that uniformly covers a portion of the periphery of the core metal member on the driver's side, which is a rear side of the vehicle, along a circumferential direction of the core metal member in the cross section of the grip member. Steering wheel.

6. 6. A steering wheel according to claim 5, The shield is configured such that the first shield portion and the second shield portion are bent and connected to each other in the cross section of the gripping member. Steering wheel.

7. 5. A steering wheel according to claim 4, The shield has a second shield portion that uniformly covers a portion of the periphery of the core metal member on the opposite side to the driver's side, which is the front side of the vehicle, along a circumferential direction of the core metal member in the cross section of the grip member. Steering wheel.

8. 4. A steering wheel according to claim 3, The gripping member is configured by interposing an insulating layer between the core metal member and the shield. Steering wheel.

9. 9. A steering wheel according to claim 8, The shield and the insulating layer are integrally formed, a connecting portion for attaching the insulating layer to the core metal member is provided on the insulating layer and the core metal member, Steering wheel.

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