Vehicle braking system

Abstract

To provide a brake device for a vehicle, by which a heat radiation property is improved.SOLUTION: A brake device 10 for a vehicle can restrain rotation of a wheel by pressing a pad 4 to a disc 3 rotatable with a wheel 2, and comprises a motor 20, a reduction gear 30, a linear motion converter 40, and an electronic circuit part 60. The motor 20 is rotated by energization. The reduction gear 30 decelerates rotation from the motor 20, and outputs the rotation. The linear conversion part 40 converts the rotation from the reduction gear 30 into a linear motion, and can press the pad to the disc. The control circuit part 60 has an electronic circuit that can control the rotation of the motor 20, and operation of the reduction gear 30 and the liner conversion part 40. At least a part of energization components of the motor 20 or the control circuit part 60 is covered with a material with higher heat conductivity than that of air.SELECTED DRAWING: Figure 1

Description

Technical Field

[0007] ,

[0001] The present invention relates to a vehicle braking device.

Background Art

[0002] Conventionally, an electric vehicle braking device that converts the rotation from a motor decelerated by a speed reducer into linear motion and presses a pad against a disk of a wheel is known.

[0003] For example, the electric braking device of Patent Document 1 is mounted on each wheel in a brake-by-wire device and integrally includes a motor, a speed reducer, a linear motion conversion unit, and an electronic circuit capable of controlling the rotation of the motor.

[0004] During braking, the pad and the disk reach a high temperature due to frictional heat. The motor also generates heat, and the power module of the electronic circuit of the output control device also generates heat. As a result, there is a possibility of failure due to reaching the heat resistance limit of the electronic components inside the device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In Patent Document 1, regarding frictional heat during braking, a heat insulating member made of a resin material having a lower thermal conductivity than metal is disposed between the power module and the speed reducer, the motor, and the linear motion conversion unit to suppress heat conduction. On the other hand, regarding heat generation of the power module, the electronic circuit is fixed to a metal plate, and another metal plate is disposed opposite thereto, thereby improving heat dissipation by utilizing the high thermal conductivity of the metal.

[0007] However, in the electric brake device described in Patent Document 1, the reducer, motor, and linear motion converter are arranged in very close proximity within the same housing. Therefore, simply placing an insulating material in between is not sufficient to suppress heat conduction between the power module and the reducer, motor, and linear motion converter, and there is a risk that frictional heat during braking may be transmitted to the motor and reducer via the linear motion converter. Furthermore, the heat dissipation effect due to being metal alone may not be sufficient to release the heat generated by the electronic circuit. Moreover, no consideration is given to motor heat generation.

[0008] In view of the above-mentioned thermal problems, the object of the present invention is to provide a vehicle brake device that improves heat dissipation. [Means for solving the problem]

[0009] The present invention relates to a vehicle brake device capable of restricting the rotation of a wheel by pressing a pad (4) against a disc (3) that is rotatable together with the wheel (2), and comprises a motor (20), a reduction gear (30), a linear motion conversion unit (40), and a control circuit unit (60).

[0010] The motor rotates when power is applied. The gearbox reduces the rotation from the motor and outputs it. The linear motion converter converts the rotation from the gearbox into linear motion, enabling the pad to press against the disc. The control circuit has an electronic circuit that can control the rotation of the motor and the operation of the gearbox and the linear motion converter.

[0011] At least a portion of the energized components of the motor or control circuit At room temperature It is covered with a material that has a higher thermal conductivity than air. The motor's outer wall is composed of a motor housing (21). The control circuit section has electronic circuits housed in a circuit housing (61). The motor housing has multiple outside air intakes (26) along the circumferential direction at the same position in the axial direction of the motor. The circuit housing has multiple outside air intakes (66) along a direction perpendicular to the axial direction of the motor, on a plane parallel to the axial direction of the motor.

[0012] Air is an insulating medium with low thermal conductivity, and although it has a heat diffusion effect through convection, it cannot be said to have high heat dissipation capabilities. On the other hand, in recent years, polymer materials such as gels or resins with higher thermal conductivity than air have been developed and are becoming available for use. Therefore, in this invention, at least a portion of the conductive components, which are heat-generating elements in the motor or control circuit, are covered with a high thermal conductivity material, and the space that was previously an air layer is replaced with a resin mold, thereby promoting smooth heat transfer from the conductive components to the outside of the device and efficiently releasing heat.

[0013] With this configuration, for example, if a continuous inflow of outside air is ensured from below, the heat generated by the device—that is, the heat generated by the heat-generating elements during braking, such as the discs and pads, motor, and electronic circuits of the control circuit—is diffused more efficiently within the resin mold than in an air layer, and is moved to the outside air in the vicinity of the device, where it is smoothly discharged. As a result, the heat from the motor and electronic circuits is efficiently released along with the frictional heat generated during braking that is transferred to the reduction gear, motor, and electronic circuits, thereby suppressing the temperature rise of the motor and electronic circuits when the vehicle brake system is in operation. [Brief explanation of the drawing]

[0014] [Figure 1] A plan view of a vehicle brake system according to one embodiment. [Figure 2] A front view of a vehicle brake system according to one embodiment. [Figure 3] A perspective view of a vehicle brake system according to one embodiment. [Figure 4] A perspective view illustrating a resin mold for a motor according to one embodiment. [Figure 5] A perspective view illustrating a resin mold for a control circuit according to one embodiment. [Figure 6] A perspective view illustrating a resin mold for a control circuit according to another embodiment. [Modes for carrying out the invention]

[0015] The following describes a vehicle brake system according to an embodiment, based on the drawings.

[0016] (One embodiment) The schematic configuration of a vehicle braking device according to one embodiment is shown in FIG. 1. Its appearance is shown in FIGS. 2-3. The vehicle braking device 10 is provided, for example, on the wheel 2 of the vehicle 1. The vehicle braking device 10 can regulate the rotation of the wheel 2 by pressing the pad 4 against the disk 3 that can rotate together with the wheel 2. Thereby, it is possible to maintain the stopped state of the vehicle 1 during parking, or to decelerate or stop the vehicle 1 during traveling.

[0017] The vehicle braking device 10 includes a motor 20, a speed reducer 30, a linear motion conversion unit 40, a control circuit unit 60, etc. The motor 20 is, for example, a three-phase brushless motor, and rotates by the energization control of a circuit main body 63 described later. When the shaft 24 of the motor 20 rotates, the speed reducer 30 is configured to decelerate the rotation from the motor 20 and output it to the linear motion conversion unit 40 side. The linear motion conversion unit 40 is configured to convert the rotation from the speed reducer 30 into linear motion and press the pad 4 against the disk 3. Thereby, the braking control state of the vehicle 1 by the vehicle braking device 10 can be maintained. The control circuit unit 60 is configured to be able to control the rotation of the motor 20, the operations of the speed reducer 30 and the linear motion conversion unit 40.

[0018] The vehicle braking device 10 has a motor housing 21, a speed reducer housing 31, and a circuit housing 61. The motor housing 21 houses the motor 20. The speed reducer housing 31 is formed, for example, in a bottomed cylindrical shape and houses the speed reducer 30. The circuit housing 61 is formed, for example, in a cylindrical shape, is provided on the side opposite to the bottom of the speed reducer housing 31, and houses the control circuit unit 60.

[0019] The motor 20 further has a stator 22 fixed to the motor housing 21, a rotor 23 provided so as to be relatively rotatable with respect to the stator 22, and a shaft 24 that rotates together with the rotor 23 and outputs torque. When the rotor 23 rotates, rotation is output from the shaft 24.

[0020] Specifically, the motor housing 21 is provided in contact with the speed reducer housing 31. The stator 22 is fixed to the inner wall of the motor housing 21. The shaft 24 is formed, for example, in a cylindrical shape. The rotor 23 is provided coaxially with the shaft 24 on one end side of the shaft 24. The other end of the shaft 24 is located inside the speed reducer housing 31. The other end side of the shaft 24 is supported inside the speed reducer housing 31 via a bearing and a part of the motor housing 21. Here, the bearing is, for example, a ball bearing. The motor 20 has a coil 25. The coil 25 is wound around the teeth of the stator 22.

[0021] The control circuit unit 60 further has a substrate 62 and a circuit body 63 in addition to the circuit housing 61. The substrate 62 is formed, for example, in a plate shape by resin and is provided inside the circuit housing 61. The circuit body 63 is an integrated circuit such as a microcomputer, for example, and is mounted on the surface of the substrate 62 on the side of the heat dissipation promotion part 611. Specifically, the circuit body 63 is a small computer having a CPU, a memory, an input / output part, etc., and based on signals from various sensors attached to the vehicle 1, etc., while controlling the energization of the coil 25 of the motor 20 and the speed reducer 30, by supplying power, the motor 20 is operated so that the rotor 23 rotates in the forward rotation direction or the reverse rotation direction, and the speed reducer 30 is also operated.

[0022] All the energization members generate some heat due to energization. In particular, the circuit body 63 of the electronic circuit 60 is an integrated circuit, and heat generating elements are densely gathered. Since the circuit body 63 controls the motor 20 by microscopically adjusting the energization pattern, amount, time, etc., a large amount of heat is instantaneously generated and may become high temperature. Therefore, it is necessary to quickly and efficiently discharge the generated heat.

[0023] In this embodiment, the entire energized components of the motor 20 (coil 25, etc.) and the energized components of the control circuit unit 60 (circuit body 63, etc.) are resin-molded with a polymer material (high thermal conductivity gel or resin) that has a higher thermal conductivity than air (Figure 1). This allows the generated heat to diffuse more efficiently within the resin mold than in the case of no resin molding (heat diffusion by the air layer), and heat radiation from the resin mold moves the heat to the outside of the device, promoting heat dissipation. Hereafter, the resin mold of the energized components of the motor 20 will be referred to as resin mold 20M, and the resin mold of the energized components of the control circuit unit 60 will be referred to as resin mold 60M. Figure 4-5 shows resin molds 20M and 60M.

[0024] In this embodiment, both the motor housing 21 and the circuit housing 61 are further provided with multiple outside air inlets 26 and 66 (Figure 1-3). The outside air inlets 26 and 66 are formed so that air from outside the device can enter and blow through the motor housing 21 and the circuit housing 61. This, combined with the configuration in which the heating element is resin-molded using a polymer material (high thermal conductivity gel or resin) with a higher thermal conductivity than air, and the configuration in which outside air is introduced into the housing, promotes heat dissipation from the device.

[0025] Refer to Figure 3 below. The coil 25 of the motor 20 generates heat when energized. In particular, during braking, if several phases generate a large amount of heat due to the three-phase current entering an electrical lock state, the motor housing 21 will become extremely hot. In order to quickly dissipate this heat to the outside, as described above, the entire coil 25 of the motor 20 is molded with a polymer material (high thermal conductivity gel or resin) that has a higher thermal conductivity than air (resin mold 20M), and the motor housing 21 has multiple outside air inlets 26 on its outer surface. With this configuration, outside air A1 that enters the motor housing 21 through the outside air inlets 26 travels along the resin mold 20M, receives heat from the resin mold 20M, becomes "heated outside air A2", and blows out to other outside air inlets 26, thereby efficiently dissipating the heat released from the coil 25 via the resin mold 20M to the outside.

[0026] The heated outside air A2 expands due to the heat, increasing in volume compared to the outside air A1 before it was heated, decreasing in specific gravity, generating buoyancy, and moving upward. The outside air inlet 26 is a void formed throughout the entire motor housing 21, including the top surface and the ground, and exhibits multiple slit-shaped openings. This ensures that, for example, outside air A1 continuously flows in from the outside air inlet 26 on the lower, ground side, and the incoming outside air A1 becomes outside air A2 heated by heat radiation from the resin mold 20M, which is then smoothly and continuously discharged from other outside air inlet 26 locations.

[0027] In this embodiment, the continuous inflow of outside air A1 is ensured by mounting the vehicle brake device 10 on a vehicle 1 equipped with an air guide plate G that guides the outside air A1 toward the mounting position of the vehicle brake device 10. As a result, the outside air A1 guided by the air guide plate G flows and is heated while receiving heat from the resin mold 20M, and then blows through. Here, the difference in the background patterns of outside air A1 and heated outside air A2 in Figure 3 reflects the gas density. That is, outside air A1 has a high density, and heated outside air A2 has a low density.

[0028] The conductive components of the control circuit section 60 are also resin-molded with a polymer material (high thermal conductivity gel or resin) that has a higher thermal conductivity than air (resin mold 60M). The circuit housing 61 is provided with an outside air intake section 66. Similar to the outside air intake section 26, the outside air intake section 66 is a void formed throughout the circuit housing 61 and exhibits multiple slit-shaped openings. With this configuration, outside air A1 entering through the outside air intake section 66 receives heat from the resin mold 60M, becomes heated outside air A2, and blows out to the opposite side of the motor housing 21, thereby efficiently discharging the heat emitted from the resin mold 60M to the outside.

[0029] As described above, the heated outside air A2 expands due to the heat, generating buoyancy and moving upward. Therefore, if the device is attached to a vehicle 1 equipped with an air guide plate G, for example, and a continuous flow of outside air A1 from below is ensured, the outside air A2 heated by heat radiation from the resin mold 60M will be smoothly and continuously discharged to the outside of the device through the outside air inlet 26.

[0030] Furthermore, as in this embodiment, when the entire energized components of the motor 20 and the control circuit unit 60 are resin-molded, not only is the above-mentioned effect of improving heat dissipation efficiency (paragraph

[0023] ) obtained, but a waterproofing effect is also obtained, which reduces the rate of electrical short circuits caused by moisture or metallic foreign matter that enters from the outside. As a result, the waterproofing structure can be simplified, and further effects such as simplification of the manufacturing process and weight reduction of the device due to the reduction in the number of parts can be expected.

[0031] (Other embodiments) The above-described embodiment shows an example in which the entire conductive components of the motor and control circuit are resin-molded. However, the extent to which the conductive components of the motor and control circuit are resin-molded is not limited to the above example, and in other embodiments, only a portion of the conductive components of the motor or control circuit may be resin-molded. For example, in the example shown in Figure 6, only the component of the conductive part of the control circuit that is expected to generate the most heat is resin-molded.

[0032] In the above-described embodiment, an example was shown in which both the motor and the conductive components of the control circuit are resin-molded. In contrast, in other embodiments, only one of the conductive components of the motor and the control circuit may be resin-molded.

[0033] In the above-described embodiment, an example was shown in which multiple outside air intakes are provided in both the motor housing and the circuit housing. In contrast, in other embodiments, multiple outside air intakes may be provided in only one of the motor housing or the circuit housing.

[0034] In the above-described embodiment, an example was shown in which each outside air intake section exhibits multiple slit-shaped openings. However, the shape of the outside air intake section is not limited to the above example, and in other embodiments, it may exhibit multiple substantially circular openings, such as perforated metal. In other words, the shape of the outside air intake section only needs to allow for the free flow of outside air into the device.

[0035] In other embodiments, the motor may be a motor other than a three-phase brushless motor.

[0036] The vehicle brake device of the present invention may be applied to all of the multiple wheels of a vehicle, or to only some of the wheels.

[0037] The vehicle brake device of the present invention can be used as a parking brake, as well as a braking brake to decelerate or stop a moving vehicle.

[0038] Thus, this disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its essence. [Explanation of symbols]

[0039] 2 wheels, 3 discs, 4 pads, 10 vehicle brakes, 20 motors, 30 Reducer, 40 Linear motion converter, 60 Control circuit

Claims

[Claim 1] A vehicle brake device capable of restricting the rotation of a wheel by pressing a pad (4) against a disc (3) that is rotatably mounted together with the wheel (2), A motor (20) that rotates when power is applied, A reduction gear (30) that reduces the rotation from the motor and outputs it, A linear motion conversion unit (40) that converts the rotation from the reduction gear into linear motion and presses the pad against the disk, A control circuit unit (60) having an electronic circuit capable of controlling the rotation of the motor, the operation of the reduction gear and the linear motion converter, Equipped with, At least a portion of the energized components of the motor or the control circuit are covered with a material that has a higher thermal conductivity than air at room temperature. The motor's outer wall is composed of a motor housing (21). The control circuit section comprises the electronic circuit housed in a circuit housing (61). The motor housing is provided with a plurality of outside air inlet sections (26) along the circumferential direction at the same position in the axial direction of the motor. The circuit housing is a vehicle brake device in which a plurality of outside air intake sections (66) are provided on a plane parallel to the axial direction of the motor, along a direction perpendicular to the axial direction of the motor.

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