Electric braking system and method for assembling the electric braking system

Abstract

Simplify the assembly process of the electric braking system. [Solution] The electric braking device (1) is arranged such that the friction material (20) is located on the outside of the first surface and comprises a housing portion (10) that opens on the first surface and partitions a cylinder (11) that houses a piston (12), a reaction force receiving portion (15) that moves in the direction of linear motion due to the reaction force of the pressing force that presses the friction material (20) against the rotating body (2), a detection portion (16) that contacts the reaction force receiving portion (15) from the second surface side opposite to the first surface of the housing portion (10) to detect the reaction force, and a detachment prevention portion (17) that is screwed into and fixed to the housing portion (10) from the second surface side of the detection portion (16) to prevent the detection portion (16) from falling out of the housing portion (10) to the second surface side.

Description

Technical Field

[0001] The present disclosure relates to an electric braking device and a method for assembling an electric braking device.

Background Art

[0002] Patent Document 1 discloses an electric braking device in which a speed reducer is connected from the radially outer direction of a linear motion conversion mechanism, and a load sensor is prevented from dropping off from the housing portion to the side opposite to the friction material by support protrusions provided on the housing portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electric braking device disclosed in Patent Document 1, due to the support protrusions, the linear motion conversion mechanism, the speed reducer, and the load sensor are assembled to the housing portion from the friction material side, and a part of the speed reduction mechanism is assembled from the side opposite to the friction material. Therefore, the assembly process becomes complicated. One aspect of the present disclosure aims to simplify the assembly process of an electric braking device.

Means for Solving the Problems

[0005] To solve the above problems, an electric braking device according to one aspect of the present disclosure transmits the rotational motion of an electric motor to a reduction mechanism, transmits the rotational motion reduced by the reduction mechanism to a rotating part of a linear motion conversion mechanism, converts the rotational motion transmitted to the rotating part into linear motion by a linear motion part of the linear motion conversion mechanism, drives a piston with the linear motion part, and applies braking force to the wheel by pressing a friction material against a rotating body that rotates together with the wheel with the piston, the electric braking device comprising: a housing part arranged such that the friction material is located on the outside of a first surface and having an opening on the first surface to demarcate a cylinder that houses the piston; a reaction force receiving part that moves in the direction of the linear motion due to the reaction force of the pressing force that presses the friction material against the rotating body; a detection part that contacts the reaction force receiving part from the second surface side opposite to the first surface of the housing part to detect the reaction force; and a detachment prevention part that is screwed into and fixed to the housing part from the second surface side of the detection part than the detection part to prevent the detection part from falling out of the housing part to the second surface side. [Effects of the Invention]

[0006] According to one aspect of this disclosure, the assembly process of an electric braking system can be simplified. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing one example of the configuration of an electric braking system according to one embodiment of the present disclosure. [Figure 2] This is a view of an electric braking device according to one embodiment of the present disclosure, as seen from the inner side. [Figure 3] This is a view of an electric braking device according to one embodiment of the present disclosure, as seen from the outer side. [Figure 4] This is a flowchart showing a method for assembling an electric braking device according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] Figure 1 is a schematic diagram showing one configuration example of an electric braking device according to one embodiment of the present disclosure. The electric braking device 1 shown in Figure 1 comprises a housing 10, a cylinder 11, a piston 12, a linear motion conversion mechanism 13, a first gear 14, a bearing 15, a detection unit 16, a fall prevention unit 17, a second gear 18, an electric motor 19, a first friction material 20, and a second friction material 21.

[0009] In the following, as indicated by the arrows in Figure 1, the outer side and inner side are defined for the housing portion 10. The outer side is an example of the first surface side. The inner side is an example of the second surface side. The outer side and the inner side are opposite each other.

[0010] As shown in Figure 1, a cylindrical cylinder 11 is enclosed within the housing portion 10. The outer side of the housing portion 10 has a first surface through which one opening of the cylinder 11 is open. The inner side of the housing portion 10 has the other opening of the cylinder 11 open, and a female thread 11A is provided further inward from that other opening of the cylinder 11.

[0011] Inside the cylinder 11, from the inner side, are the piston 12, the linear motion conversion mechanism 13, and the first gear section 14. Inside the housing section 10, the second gear section 18 is inserted. The linear motion conversion mechanism 13 is a screw mechanism having a rotating part 13A and a linear motion part 13B. The rotating part 13A is, for example, a screw shaft and rotates coaxially with the first gear part 14. The linear motion part 13B is, for example, a nut and converts the rotation of the rotating part 13A into linear motion in the direction of the rotation axis of the rotating part 13A. The first gear section 14 and the second gear section 18 are included in a reduction mechanism that reduces the rotational motion of the electric motor 19 and transmits it to the rotating section 13A of the linear motion conversion mechanism 13. The first gear section 14 has teeth on its outer surface and rotates coaxially with the linear motion conversion mechanism 13. The second gear section 18 has teeth on its outer surface. In the electric braking device 1, the teeth of the second gear section 18 mesh with the teeth of the first gear section 14. The piston 12 is housed inside the cylinder 11 and is configured to slide within the cylinder 11, and is driven by the linear motion unit 13B. The piston 12 moves to the outer side by contacting the linear motion unit 13B, for example. Alternatively, the piston 12 can move to the inner side by receiving force from the rotating body 2 without contacting the linear motion unit 13B. The piston 12 may also be fixed to the linear motion unit 13B and configured to move linearly as an integral part of the linear motion unit 13B.

[0012] A first friction material 20 is positioned outside the first surface (outside the first surface) at the opening of the cylinder 11 on the outer side of the housing portion 10. The piston 12 is positioned so that it can contact the first friction material 20 from the inside of the cylinder 11. The housing portion 10 has a claw portion 10A on the outer side of the first friction material 20. The claw portion 10A holds a second friction material 21 which is positioned opposite the first friction material 20. The second friction material 21 is an example of an outer friction material.

[0013] On the inner side of the housing portion 10, the bearing 15, detection portion 16, and fall prevention portion 17 are arranged on the inner side of the other opening of the cylinder 11 that opens on the inner side of the housing portion 10. The bearing 15 is an example of a reaction force receiving part, and supports the rotating part 13A from the inner side. The detection unit 16 is an axial force sensor, and its outer side is in contact with the bearing 15, detecting the force applied to the bearing 15.

[0014] The fall prevention part 17 has a first part 17A and a second part 17B. Part 1 17A is cylindrical and has a male thread 171 on its side. The male thread 171 is formed to be screwable with the female thread 11A of the housing part 10. The second part 17B is a cylindrical sensor holder and has an inner edge portion 172 and an outer edge portion 173. The inner edge portion 172 of the second part 17B contacts the detection part 16 from the inner side. The outer edge portion 173 of the second part 17B contacts the bottom portion 174 of the first part 17A from the outer side. The rotation of the detection part 16 is suppressed by the frictional forces generated on the contact surfaces between the inner edge portion 172 of the second part 17B and the detection part 16 and between the outer edge portion 173 of the second part 17B and the bottom portion 174 of the first part 17A. The first part 17A screwed to the female screw 11A of the housing part 10 locks the second part 17B, and the inner edge portion 172 of the second part 17B locks the detection part 16, so that the detachment prevention part 17 can prevent the detection part 16 from detaching to the inner side.

[0015] The detachment prevention part 17 is located on the inner side of the second gear part 18. FIG. 2 is a view of the electric braking device according to an embodiment of the present disclosure as seen from the inner side. As shown in FIG. 2, a part of the detachment prevention part 17 overlaps the side surface 18A of the second gear part 18, and the second gear part 18 can be prevented from detaching to the inner side.

[0016] FIG. 3 is a view of the electric braking device according to an embodiment of the present disclosure as seen from the outer side. In the electric braking device 1, since the detachment prevention part 17 is configured separately from the housing part 10, the insertion of the piston 12 or the like into the cylinder 11 from the inner side of the housing part 10 is not hindered as in the prior art. Therefore, as shown in FIG. 3, there is no need to provide a hole for access to the cylinder 11 in the plug part 10A. Therefore, in the design of the plug part 10A, the degree of freedom in shape can be improved.

[0017] (Operation of the electric braking device) The rotational motion of the electric motor 19 is decelerated by a plurality of gears (not shown), a first gear portion 14, and a second gear portion 18, and is transmitted to a rotating portion 13A of the linear motion conversion mechanism 13. The rotation of the rotating portion 13A of the linear motion conversion mechanism 13 is converted by a linear motion portion 13B into a linear motion in the axial direction of the rotating portion 13A. When the linear motion portion 13B moves linearly toward the outer side, the piston 12 moves linearly toward the outer side, and presses a first friction material 20 against a rotating body 2 that rotates together with the wheel. At this time, the rotating body 2 is sandwiched between the first friction material 20 and the second friction material 21. When the first friction material 20 and the second friction material 21 are pressed against the rotating body 2, a braking force is applied to the wheel.

[0018] When the piston 12 presses the first friction material 20 against the rotating body 2, a reaction force against the pressing force is applied from the first friction material 20 to the piston 12. The reaction force applied to the piston 12 is transmitted from the linear motion portion 13B to the rotating portion 13A, and is transmitted from the rotating portion 13A to the bearing 15. Since the detection portion 16 is locked to the housing portion 10 by the anti-drop portion 17, the reaction force transmitted to the bearing 15 can be detected.

[0019] (Assembly method) FIG. 4 is a flowchart showing an assembly method of an electric braking device according to an embodiment of the present disclosure. In the first step shown as S100, the piston 12 is inserted into the cylinder 11 from the inner side of the housing portion 10. When the linear motion conversion mechanism 13 is fixed to the piston 12 in advance, the first step shown as S100 may be skipped, and the piston 12 may be inserted into the cylinder 11 in the second step shown as S200.

[0020] In the second step shown as S200, the linear motion conversion mechanism 13 is inserted into the cylinder 11 from the inner side of the housing portion 10 and installed inside the cylinder 11. At this time, the rotating portion 13A and the linear motion portion 13B of the linear motion conversion mechanism 13 may be assembled in advance. When the linear motion conversion mechanism 13 is fixed to the piston 12 in advance and the first step shown as S100 is skipped, the piston 12 is inserted together with the linear motion conversion mechanism 13 in the second step shown as S200. Alternatively, a cylinder pin or the like may be inserted to restrict the rotation of the linear motion section 13B of the linear motion conversion mechanism 13.

[0021] In the third step shown in S300, the reduction mechanism, bearings, and detection unit are installed in the housing 10. In the third step, the first gear section 14, the second gear section 18, the bearings 15, and the detection unit 16 are assembled to the housing 10 from the inner side. The first gear section 14 is fixed, for example, to the rotating section 13A of the linear motion conversion mechanism 13. The second gear section 18 is fixed, for example, to the rotating shaft of the electric motor 19 and meshes with the first gear section 14.

[0022] In the fourth step shown in S400, a fall prevention part 17 is installed on the housing part 10. The second part 17B is brought into contact with the detection part 16 from the inner side, and the bottom part 174 of the first part 17A is brought into contact with the outer edge part 173 of the second part 17B from the inner side. At this time, the detection part 16 may be press-fitted into the second part 17B to restrict their relative rotation. Then, while restricting the relative rotation between the second part 17B and the housing part 10 with a tool or the like, the male screw 171 on the side of the first part 17A is screwed into the female screw 11A of the housing part 10. The relative angle of the detection part 16 with respect to the housing part 10 can be determined, and the electrical connection between the base case fixed to the housing part 10 and the detection part 16 is stabilized.

[0023] 〔summary〕 An electric braking device according to one aspect of the present disclosure transmits the rotational motion of an electric motor to a reduction mechanism, transmits the rotational motion reduced by the reduction mechanism to a rotating part of a linear motion conversion mechanism, converts the rotational motion transmitted to the rotating part into linear motion by a linear motion part of the linear motion conversion mechanism, drives a piston with the linear motion part, and applies braking force to the wheel by pressing a friction material against a rotating body that rotates together with the wheel with the piston, the electric braking device comprising: a housing part arranged such that the friction material is located on the outside of a first surface and partitioning a cylinder that opens on the first surface and houses the piston; a reaction force receiving part that moves in the direction of the linear motion due to the reaction force of the pressing force that presses the friction material against the rotating body; a detection part that contacts the reaction force receiving part from the second surface side opposite to the first surface of the housing part and detects the reaction force; and a detachment prevention part that is screwed into and fixed to the housing part from the second surface side of the detection part than the detection part and prevents the detection part from falling out of the housing part to the second surface side. The above-described electric braking device is screwed into and fixed to the housing from the second side of the detection unit, and is equipped with a fall prevention unit that prevents the detection unit from falling out of the housing to the second side. Because the fall prevention unit is detachable and prevents it from falling out to the second side, the piston, linear motion conversion mechanism and detection unit can be easily assembled to the housing from the second side of the housing, simplifying the assembly process of the electric braking device. Furthermore, the detection unit contacts the reaction force receiving unit from the second surface side to detect the reaction force. Because this axial force sensor is not attached to the rotating part, axial force sensors other than ring-type axial force sensors can be used, improving the design flexibility of the electric braking system.

[0024] An electric braking device according to one aspect of the present disclosure, in the above embodiment, the reduction mechanism comprises a first gear portion arranged on the first surface side of the anti-detachment portion, which rotates coaxially with the rotating portion together with the rotating portion and has teeth on its outer circumference, and a second gear portion which meshes with the first gear portion to transmit the rotational motion of the electric motor to the rotating portion, and the anti-detachment portion is configured to prevent the second gear portion from falling off to the second surface side, such that when the second surface side of the housing portion is viewed from outside the anti-detachment portion, the anti-detachment portion overlaps with at least a part of the second gear portion. By positioning the reduction mechanism on the first surface side of the anti-detachment section, providing teeth on the outer circumference of the first gear section, and meshing the second gear section with the first gear section, the second gear section can also be easily assembled from the second surface side of the housing section, thereby simplifying the assembly process of the electric braking device. The anti-detachment part further prevents the second gear from falling off towards the second surface. Because the anti-detachment part prevents the second gear from falling off towards the second surface, the assembly of the electric braking device becomes easier.

[0025] In one aspect of the present disclosure, in the present embodiment, the friction material is arranged on both sides in the direction of the rotation axis of the rotating body, and the housing portion has a claw portion that supports the outer friction material, which is arranged on the opposite side of the piston from the rotating body, and the claw portion is configured to overlap the cylinder when the first surface of the housing portion is viewed from outside the claw portion. As described in Patent Document 1, when assembling a linear motion conversion mechanism, etc., to the housing from the friction material side, a hole is required in the claw portion for passing the component through. Also, when machining the housing portion, a hole is required in the claw portion for passing the machining tool through. Since the linear motion conversion mechanism, etc., can be assembled from the second surface side, there is no need to provide a hole in the claw portion. When the housing is viewed from the first surface, the claw portion is configured to overlap the cylinder, which prevents the piston and other components from falling out of the cylinder towards the first surface, thus facilitating the assembly of the electric braking device.

[0026] An assembly method for an electric braking device according to one aspect of the present disclosure is an assembly method for an electric braking device according to the above aspect, comprising: a first step of inserting the piston into the housing from the second side; a second step of installing the linear motion conversion mechanism into the housing from the second side; a third step of installing the reduction mechanism and the detection unit into the housing from the second side; and a fourth step of screwing the anti-detachment unit into the housing from the second side. In the above assembly method, the piston, linear motion conversion mechanism, reduction mechanism, detection unit, and anti-detachment unit are assembled to the housing in a single direction, thus simplifying the assembly process.

[0027] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. [Explanation of Symbols]

[0028] 1 Electric braking device 2. Solids of revolution 10 Housing section 11 cylinders 12 pistons 13 Linear motion conversion mechanism 13A Rotating part 13B Linear motion section 14. First gear section 15 bearings 16 Detection unit 17 Falling prevention part 18. Second gear section 19 Electric motor 20 1st friction material 21 2nd friction material

Claims

1. In an electric braking device that transmits the rotational motion of an electric motor to a reduction mechanism, transmits the rotational motion reduced by the reduction mechanism to the rotating part of a linear motion conversion mechanism, converts the rotational motion transmitted to the rotating part into linear motion by the linear motion part of the linear motion conversion mechanism, drives a piston with the linear motion part, and applies braking force to the wheel by pressing a friction material against a rotating body that rotates together with the wheel with the piston, The friction material is positioned on the outside of the first surface, and the housing portion is open to the first surface and demarcates the cylinder that houses the piston, A reaction force receiving part moves in the direction of the linear motion due to the reaction force of the pressing force that presses the friction material against the rotating body, A detection unit that contacts the reaction force receiving portion from the second surface side opposite to the first surface of the housing portion to detect the reaction force, An electric braking device comprising: a fall prevention part that is screwed into and fixed to the housing from the second surface side of the detection part, and prevents the detection part from falling out of the housing towards the second surface side.

2. The reduction mechanism is positioned on the first surface side of the fall prevention portion and includes a first gear portion that rotates coaxially with the rotating portion and has teeth on its outer circumference, and a second gear portion that meshes with the first gear portion to transmit the rotational motion of the electric motor to the rotating portion. The electric braking device according to claim 1, wherein the anti-detachment portion is configured to prevent the second gear portion from falling off to the second surface side, such that when the second surface side of the housing portion is viewed from outside the anti-detachment portion, it overlaps with at least a part of the second gear portion.

3. In an electric braking device in which the friction material is arranged on both sides in the direction of the rotation axis of the rotating body, The electric braking device according to claim 1 or 2, wherein the housing portion has a claw portion that supports an outer friction material which is positioned on the opposite side of the piston from the rotating body, and the claw portion is configured such that when the first surface of the housing portion is viewed from outside the claw portion, it overlaps the cylinder.

4. A method for assembling an electric braking device according to claim 1, The first step is to insert the piston into the housing portion from the second side, A second step involves installing the linear motion conversion mechanism in the housing portion from the second side, A third step involves installing the reduction mechanism and the detection unit in the housing portion from the second side, A fourth step involves screwing the anti-detachment part into the housing portion from the second side and installing it there. A method for assembling an electric braking system, including [a specific component].

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