Electric braking device

Abstract

This prevents misalignment of the electrical connection terminals in the detection unit of the electric braking system. [Solution] The electric braking device (1) comprises a housing portion (10) on which a friction material (20) is located on the outside of a first surface, a fall prevention portion (17) that prevents the detection portion (16) from falling out of the housing portion (10) to the second surface side opposite to the first surface of the housing portion (10), and a locking portion (11A) provided on the housing portion (10) that locks the fall prevention portion (17).

Description

Technical Field

[0001] This disclosure relates to an electric braking device.

Background Art

[0002] Patent Document 1 discloses a technique in which a sensor assembly including a load sensor and a sensor cover is screwed and assembled to a housing. The load sensor and the control board are electrically connected via an electrical connection terminal of the load sensor and a contact mounted on the control board.

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, since the sensor assembly is screwed and assembled to the housing, the load sensor may rotate due to the frictional force between the sensor cover and the load sensor, and the electrical connection terminal of the detection part such as the load sensor may shift in the rotational direction with respect to the contact. One aspect of this disclosure aims to suppress the occurrence of positional deviation in the electrical connection terminal of the detection part of the 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 converts the rotational motion of an electric motor into linear motion of a linear motion unit using a linear motion conversion mechanism, drives a piston with the linear motion unit, and applies braking force to a 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 portion which is arranged such that the friction material is located on the outside of the first surface and opens to the first surface to demarcate a cylinder that houses the piston; a detection unit which contacts an interlocking member which is interlocked with the piston and detects the reaction force of the force that presses the friction material against the rotating body; a detachment prevention unit which prevents the detection unit from falling out of the housing portion to the second surface side of the housing portion opposite to the first surface; and a locking unit which is provided in the housing portion and locks the detachment prevention unit, wherein the detachment prevention unit is elastic and is positioned within the locking unit in a state deformed by an external force, and is configured to be locked by the locking unit when the external force is removed while it is positioned within the locking unit. [Effects of the Invention]

[0006] According to one aspect of this disclosure, it is possible to suppress misalignment of the electrical connection terminals of the detection unit of the electric braking device. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing one example configuration of an electric braking device according to Embodiment 1 of this disclosure. [Figure 2] This is a view of the electric braking device according to Embodiment 1 of the present disclosure, as seen from the inner side. [Figure 3] This flowchart shows the assembly method for the electric braking device according to Embodiment 1 of this disclosure. [Figure 4] This is a view of the electric braking device according to Embodiment 2 of the present disclosure, as seen from the inner side. [Figure 5] This is a diagram used to explain the fall prevention part according to Embodiment 3 of this disclosure. [Modes for carrying out the invention]

[0008] [Embodiment 1] Figure 1 is a schematic diagram showing one example configuration of an electric braking device according to Embodiment 1 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, and a friction material 20. In the following, as indicated by the arrows in Figure 1, the housing portion 10 is defined as having an outer side and an inner side. The outer side surface of the housing portion 10 is defined as the first surface, and the inner side surface is defined as the second surface. The outer side is an example of the first side. The outer side and the inner side are on opposite sides of each other.

[0009] As shown in Figure 1, a cylindrical cylinder 11 is enclosed within the housing portion 10. One opening of the cylinder 11 is open on the outer side of the housing portion 10. The other opening of the cylinder 11 is open on the inner side of the housing portion 10. The housing portion 10 has a groove 11A on the other opening side of the cylinder 11. This groove 11A is a locking portion according to Embodiment 1.

[0010] 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 configured to slide inside the cylinder 11 and is driven by the linear motion unit 13B. The piston 12 is, for example, fixed to the linear motion unit 13B and moves linearly in conjunction with the linear motion unit 13B.

[0011] A friction material 20 is placed in the opening of the cylinder 11 that is on the outer side of the housing portion 10. The piston 12 is positioned so that it can come into contact with the friction material 20 from the inside of the cylinder 11.

[0012] 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 an interlocking member 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. The detection unit 16 has an electrical connection terminal 16A on its inner side.

[0013] The fall prevention part 17 has a first part 17A and a second part 17B, and prevents the detection part 16 from falling off to the inner side. Part 1 17A is, for example, a snap ring. Part of Part 1 17A is fitted into the groove 11A of the housing part 10, and the other part is in contact with Part 2 17B outside the groove 11A. The second part 17B is, for example, a cylindrical sensor holder, with one part contacting the detection unit 16 from the inner side and the other part abutting against the first part 17A. The second part 17B has a projection 170 on the outer side. The projection 170 is an example of a rotation prevention part and is fitted into a recess 150 provided in the bearing 15 from the inner side. This allows the rotational force of the bearing 15 to be prevented by the projection 170 rather than the detection unit 16. Furthermore, the bottom surface of the recess 150 of the bearing 15 and the projection 170 are configured not to contact in the direction of the rotation axis. This prevents the bottom surface of the recess 150 of the bearing 15 and the projection 170 from contacting each other and dispersing the reaction force of the pressing force input to the bearing 15 between the projection 170 and the detection unit 16.

[0014] The housing part 10 has a gear installation part 10A on the inner side. In the gear installation part 10A, the second gear part 18 is accommodated so as to be able to mesh with the first gear part 14. The anti-drop part 17 is located on the inner side of the second gear part 18 accommodated in the gear installation part 10A.

[0015] 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, the first part 17A of the anti-drop part 17 is in a C-shaped ring form. Insertion holes 171A are provided at the end parts 171 at both ends of the C shape of the first part 17A. The insertion hole 171A is a hole into which a tool is inserted when inserting the first part 17A into the groove 11A of the housing part 10. The first part 17A is formed of an elastic material and can reduce the opening partitioned between the end parts 171 at both ends of the C shape.

[0016] The end part 171 of the first part 17A protrudes outward in the radial direction when viewed from the inner side. The groove 11A of the housing part 10 is not provided in the vicinity of the gear installation part 10A. In a state where the first part 17A is inserted into the groove 11A of the housing part 10, the end part 171 of the first part 17A is arranged at a part where the groove 11A is not provided and protrudes toward the gear installation part 10A. As shown in FIG. 2, the end part 171 of the first part 17A protrudes from the outer edge of the second part 17B when viewed from the inner side.

[0017] A part of the second part 17B overlaps a part of the second gear part 18 when the electric braking device 1 is viewed from the inner side. Therefore, the anti-drop part 17 can prevent the second gear part 18 from dropping to the inner side.

[0018] (Assembly method) FIG. 3 is a flowchart showing an assembly method of the electric braking device according to Embodiment 1 of the present disclosure. In the first step shown in S100, the piston 12 is inserted into the cylinder 11 from the inner side of the housing part 10. At this time, when the linear motion conversion mechanism 13 is fixed to the piston 12 in advance, the first step shown in S100 may be skipped and the piston 12 may be inserted and installed in the cylinder 11 in the second step shown in S200.

[0019] In the second step shown in S200, the linear motion conversion mechanism 13 is inserted into the cylinder 11 from the inner side of the housing part 10 and installed inside the cylinder 11. At this time, the rotating part 13A and the linear motion part 13B of the linear motion conversion mechanism 13 may be pre-assembled. Also, a cylinder pin or the like for restricting the rotation of the linear motion part 13B of the linear motion conversion mechanism 13 may be inserted.

[0020] In the third step shown in S300, a speed reduction mechanism, a bearing, and a detection part are installed in the housing part 10. In the third step, the first gear part 14, the second gear part 18, the bearing 15, and the detection part 16 are assembled into the housing part 10 from the inner side of the housing part 10. The first gear part 14 is fixed to, for example, the rotating part 13A of the linear motion conversion mechanism 13. The second gear part 18 is fixed to a rotating shaft via a plurality of reduction gears (not shown) in the gear installation part 10A and meshed with the first gear part 14.

[0021] In the fourth step shown in S400, the anti-drop part 17 is installed in the housing part 10. For example, the second part 17B is arranged so as to contact the detection part 16 from the inner side, and the first part 17A is inserted into the groove part 11A of the housing part 10 so as to contact the second part 17B from the inner side.

[0022] When the first part 17A is inserted into the groove 11A of the housing part 10, a tool is inserted into each of the insertion holes 171A at both ends of the C-shape. The first part 17A is deformed by the external force applied by the tool so that the opening between the ends 171 at both ends of the C-shape is reduced. At this time, the outer diameter of the first part 17A becomes smaller than the inner diameter of the cylinder 11. The first part 17A is inserted into the groove 11A of the housing part 10 in its deformed state. At this time, the first part 17A is positioned so that the insertion holes 171A at the ends 171 protrude from the outer edge of the second part 17B. After the first part 17A is inserted into the groove 11A of the housing part 10, the tool is removed from the insertion holes 171A, and the external force that deformed the first part 17A is removed, and the first part 17A returns to its original shape. The groove 11A of the housing portion 10 locks the first portion 17A, preventing the first portion 17A from falling out to the inner side. The first portion 17A locks the second portion 17B, preventing the second portion 17B from falling out to the inner side. In other words, the groove 11A of the housing portion 10 prevents the anti-detachment portion 17 from falling out to the inner side.

[0023] Conventionally, snap rings have an end with an insertion hole that faces radially inward. Therefore, when inserting a conventional snap ring into the groove 11A of the housing portion 10, the tool may come into contact with the second portion 17B. The first portion 17A is formed such that the insertion hole 171A protrudes from the outer edge of the second portion 17B, making it difficult for a tool inserted into the insertion hole 171A to come into contact with the second portion 17B. Therefore, when inserting the first portion 17A into the groove 11A of the housing portion 10, the first portion 17A can be easily maintained in a retracted state, making assembly easy.

[0024] When the detection unit 16 is brought into contact with the bearing 15 from the inner side, it is not necessary to rotate the detection unit 16. Also, when the second part 17B of the anti-detachment unit 17 is brought into contact with the detection unit 16 from the inner side, it is not necessary to rotate the detection unit 16 and the second part 17B. When the first part 17A of the anti-detachment unit 17 is inserted into the groove 11A of the housing unit 10, it is not necessary to rotate the detection unit 16, the first part 17A, and the second part 17B.

[0025] Furthermore, the projection 170 of the second part 17B is fitted from the inner side to the bearing 15, which the detection unit 16 contacts from the inner side. The fitting between the recess of the bearing 15 and the projection 170 restricts the bearing 15 from rotating together with the rotating part 13A of the linear motion conversion mechanism 13. The second part 17B is in contact with the detection unit 16, at least from the inner side. The friction between the second part 17B and the detection unit 16 restricts the detection unit 16 from rotating together with the bearing 15. The first part 17A is in contact with the second part 17B from the inner side. The friction between the first part 17A and the second part 17B restricts the second part 17B from rotating together with the detection unit 16. In other words, the detection unit 16 is restricted from rotating together with the rotating part 13A of the linear motion conversion mechanism 13. Therefore, the position of the electrical connection terminal 16A of the detection unit 16 is less likely to shift during the assembly of the electric braking device 1.

[0026] (Operation of the electric braking system) The rotational motion of the electric motor 19 is reduced by a plurality of reduction gears (not shown), a first gear section 14 and a second gear section 18, and transmitted to the rotating section 13A of the linear motion conversion mechanism 13. The rotation of the rotating section 13A of the linear motion conversion mechanism 13 is converted into linear motion in the direction of the rotation axis of the rotating section 13A by the linear motion section 13B. When the linear motion section 13B moves linearly toward the outer side, the piston 12 also moves linearly toward the outer side, pressing the friction material 20 against the rotating body 2 which rotates with the wheel. The pressure of the friction material 20 against the rotating body 2 applies a braking force to the wheel.

[0027] When the piston 12 presses the friction material 20 against the rotating body 2, a reaction force against that pressing force is applied from the friction material 20 to the piston 12. The reaction force applied to the piston 12 is transmitted from the linear motion part 13B to the rotating part 13A, and from the rotating part 13A to the bearing 15. In other words, the bearing 15 moves in conjunction with the piston 12 due to the reaction force applied to the piston 12. Since the detection unit 16 is locked to the housing part 10 by the fall prevention part 17, it can detect the reaction force transmitted to the bearing 15.

[0028] [Embodiment 2] Embodiment 2 of this disclosure will be described below. For the sake of clarity, components having the same function as those described in Embodiment 1 will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0029] Figure 4 is a view of the electric braking device according to Embodiment 2 of the present disclosure, as seen from the inner side. The second part 17B according to Embodiment 2 has a flange portion 172 that protrudes from the gear mounting portion 10A. The flange portion 172 overlaps the second gear portion 18 when viewed from the inner side. This flange portion 172 is an example of a rotation prevention portion.

[0030] In Embodiment 2, the housing portion 10 has a shape such that the portion 11B near the boundary between the cylinder 11 and the gear mounting portion 10A can contact the flange portion 172 of the second portion 17B in Embodiment 2. In Embodiment 2, the second portion 17B does not rotate in the rotational direction of the rotating portion 13A because the flange portion 172 abuts against the portion 11B near the boundary of the housing portion 10. Therefore, the detection portion 16 in Embodiment 2 is more strongly restricted from rotating together with the rotating portion 13A of the linear motion conversion mechanism 13 than in Embodiment 1.

[0031] [Embodiment 3] Embodiment 3 of this disclosure will be described below. For the sake of convenience, components having the same function as those described in Embodiments 1 and 2 above will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0032] Figure 5 is a diagram used to explain the anti-detachment part according to Embodiment 3 of the present disclosure. In the anti-detachment part 17 according to Embodiment 3 shown in Figure 5, the second part 17B has a plurality of teeth 173 on its outer circumference like a gear. The first part 17A according to Embodiment 3 is a C-shaped ring snap ring. The first part 17A according to Embodiment 3 has a claw portion 174 at at least one of the ends 171 at both ends of the C shape that can be inserted between the teeth 173 of the second part 17B according to Embodiment 3.

[0033] In the third embodiment, the anti-detachment part 17 is configured such that the claw portion 174 of the first part 17A is inserted between the teeth 173 of the second part 17B, thereby restricting the rotation of the first part 17A relative to the second part 17B.

[0034] In Embodiment 3, it is preferable that the first part 17A and the housing part 10 are configured such that the claw portion 174 abuts against the boundary vicinity portion 11B. This restricts the rotation of the first part 17A relative to the housing part 10.

[0035] [Variation] In Embodiment 1 described above, the first part 17A of the fall prevention part 17 is a C-shaped ring snap ring, but it is not limited to this. The first part 17A in Embodiment 1 may be, for example, an O-ring.

[0036] In embodiments 1 to 3 described above, the housing portion 10 has a groove 11A into which a part of the first portion 17A is fitted. However, the groove into which a part of the first portion 17A is fitted may be provided in something other than the housing portion 10. For example, it may be provided in another member screwed into the housing portion.

[0037] 〔summary〕 An electric braking device according to one aspect of the present disclosure converts the rotational motion of an electric motor into linear motion of a linear motion unit using a linear motion conversion mechanism, drives a piston with the linear motion unit, and applies braking force to a 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 portion arranged such that the friction material is located on the outside of a first surface and opening on the first surface to demarcate a cylinder that houses the piston; a detection unit that contacts an interlocking member that is interlocked with the piston and detects the reaction force of the force that presses the friction material against the rotating body; a detachment prevention unit that prevents the detection unit from falling out of the housing portion to the second surface side of the housing portion opposite to the first surface; and a locking unit provided on the housing portion to lock the detachment prevention unit, wherein the detachment prevention unit is elastic and is positioned within the locking unit in a deformed state due to an external force, and is configured to be locked by the locking unit when the external force is removed while it is positioned within the locking unit. In the above-described electric braking device, the detection unit that detects the reaction force of the pressing force is locked to a locking part of the housing by an elastic anti-detachment part. The anti-detachment part is positioned within the locking part provided in the housing in a state deformed by an external force, and when the external force is removed while it is positioned within the locking part, it locks into the locking part. In other words, the anti-detachment part can be locked to the housing without rotating. Therefore, rotation of the detection unit when assembling it to the housing can be suppressed. This can suppress misalignment of the electrical connection terminals of the detection unit relative to the contacts, and can suppress the occurrence of electrical connection failures between the detection unit and the control circuit.

[0038] In an electric braking device according to one aspect of the present disclosure, in the above embodiment, the locking portion is a groove provided in the housing portion, and the fall prevention portion is a C-shaped ring, which deforms into a state in which the opening of the C shape is reduced when placed in the groove due to an external force. Since the fall prevention mechanism is configured so that the C-shaped opening shrinks due to external force, the structure of the fall prevention mechanism can be simplified.

[0039] In an electric braking device according to one aspect of the present disclosure, in the above embodiment, the fall prevention portion is provided with insertion holes at both ends of the C-shape that demarcates the opening, into which a tool used during assembly is inserted. Insertion holes are provided at both ends of the C-shape that demarcates the opening, into which tools used during assembly are inserted. This makes it easier to assemble the anti-detachment part to the housing using a tool, and also makes it easier to assemble the anti-detachment part to the housing without the detection part rotating.

[0040] In one aspect of the present disclosure, the electric braking device, in the above embodiment, has a rotation prevention unit that prevents the detection unit from rotating in the rotational direction of the rotating unit of the linear motion conversion mechanism due to the reaction force. Since the anti-detachment part has an anti-rotation part, it can suppress the rotation of the detection part after assembly. Therefore, it can further suppress the detection part from rotating in the direction of rotation of the rotating part.

[0041] [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]

[0042] 1 Electric braking device 2. Solids of revolution 10 Housing section 11 cylinders 11A Groove 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 Friction material

Claims

1. In an electric braking device that converts the rotational motion of an electric motor into linear motion of a linear motion unit using a linear motion conversion mechanism, drives a piston with the linear motion unit, and applies braking force to a 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 detection unit that contacts an interlocking member that is linked to the piston and detects the reaction force of the force that presses the friction material against the rotating body, The detection unit includes a fall prevention unit that prevents the detection unit from falling out of the housing unit toward the second surface of the housing unit opposite to the first surface, The housing portion is provided with a locking portion for engaging the fall prevention portion, The electric braking device is characterized in that the anti-detachment part is elastic, is positioned within the locking part in a state deformed by an external force, and is locked by the locking part when the external force is removed while it is positioned within the locking part.

2. The locking portion is a groove provided in the housing portion, The electric braking device according to claim 1, wherein the anti-detachment part is in the shape of a C-shaped ring, and when placed in the groove, it deforms into a state in which the opening of the C shape is reduced by an external force.

3. The electric braking device according to claim 2, wherein the fall prevention part is provided with insertion holes at both ends of the C-shape that demarcates the opening, into which tools used during assembly are inserted.

4. The electric braking device according to claim 1, wherein the fall prevention part has a rotation prevention part that prevents the detection part from rotating in the rotation direction of the rotating part of the linear motion conversion mechanism due to the reaction force.

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