Temperature detector

Abstract

To provide a temperature detector that can improve reliability.SOLUTION: A temperature detector 10 is provided on a brake shoe 92 of a drum brake 90 of a vehicle. The temperature detector comprises a temperature sensor 20 for detecting the temperature of the brake shoe. The temperature sensor has a sheath 21 accommodating a core wire 212 inside it, a compensation lead wire 22 connected to the core wire, a sleeve 23 covering a connection point 24 between the core wire and the compensation lead wire, and encapsulation components 25, 27 that block water ingress from a gap between the inner surface of the sleeve and the outer surface of the sheath, and the outer surface of the compensation lead wire.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a temperature detection device. [Background technology]

[0002] A temperature detection device has been known that uses a temperature sensor attached to the brake shoe of a drum brake used in vehicles such as trucks, buses, and trailers to detect abnormal conditions in which high temperatures are generated due to poor adjustment of the drum brake mechanism or bearing mechanism. The temperature sensor is held in place by a mounting jig attached to the rim of the brake shoe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-160160 Summary of the Invention [Problem to be solved by the invention]

[0004] The inside of a drum brake brake drum may be exposed to a wet environment when driving in the rain or when the vehicle is washed. In this case, if water seeps into the connection between the extension and lead of the temperature sensor, the insulation resistance may decrease, impairing the function of the temperature sensor. As such, the conventional configuration leaves room for improvement in terms of improving the waterproofness of the temperature sensor and improving the reliability of the temperature detection device.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a temperature detection device that can improve reliability. [Means for solving the problem]

[0006] To achieve the above object, one aspect of the temperature detection device is provided on a brake shoe of a vehicle drum brake. The temperature detection device includes a temperature sensor for detecting the temperature of the brake shoe, the temperature sensor including a sheath that houses a core wire therein, a compensation lead wire connected to the core wire, a sleeve that covers the connection between the core wire and the compensation lead wire, and a sealing member that blocks water from entering between the inner surface of the sleeve and the outer surface of the sheath and the outer surface of the compensation lead wire.

[0007] According to this, the sealing member can prevent water from entering the inside of the sleeve, thereby improving the reliability of the temperature detection device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a drum brake according to a first embodiment. [Figure 2] FIG. 1 is a perspective view showing an example of a state in which the temperature detection device according to the first embodiment is attached to a brake shoe; [Figure 3] FIG. 1 is a plan view schematically illustrating an example of a configuration around a sleeve in a temperature sensor according to a first embodiment; [Figure 4] FIG. 1 is an enlarged cross-sectional view showing an example of the configuration of the temperature sensor according to the first embodiment near the tip end of the sleeve; [Figure 5] FIG. 1 is an enlarged cross-sectional view showing an example of the configuration of the temperature sensor according to the first embodiment near the base end side of the sleeve. [Figure 6] FIG. 10 is a partial cross-sectional view schematically illustrating an example of the configuration of a sealing member in the temperature sensor according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, several embodiments will be described with reference to the drawings. Note that substantially the same components in the respective embodiments will be denoted by the same reference numerals, and the description thereof will be omitted.

[0010] (First embodiment) First, the first embodiment will be described with reference to FIGS. The temperature detecting device 10 is provided on a brake shoe 92 of a drum brake 90 mounted on a vehicle such as a truck, a bus, or a trailer. The temperature detecting device 10 is used to detect an abnormal temperature of the drum brake 90.

[0011] As shown in FIG. 1, the drum brake 90 includes a brake drum 91, brake shoes 92, brake linings 93, an operating cam 94, and a return spring 95. The brake drum 91 forms the outer shell of the drum brake 90. The brake drum 91 is formed in a cylindrical shape with one side open and a bottom. The brake drum 91 rotates integrally with a wheel (not shown). A pair of brake shoes 92 is provided along the inner circumferential surface of the brake drum 91.

[0012] The brake shoe 92 has a web portion 921 and a rim portion 922. The web portion 921 is formed from a plate-like member and extends in an arc shape. The rim portion 922 is attached to the outer peripheral surface of the web portion 921. The outer peripheral surface of the rim portion 922 is positioned so as to be spaced apart from the inner peripheral surface of the brake drum 91. The base end of the rim portion 922 is rotatably supported by an anchor pin 96. In other words, the rim portion 922 is rotatable around the anchor pin 96.

[0013] The brake linings 93 are attached to the rim portions 922 of the brake shoes 92. The brake linings 93 are disposed facing the inner peripheral surface of the brake drum 91. The brake linings 93 are pressed against the inner peripheral surface of the brake drum 91 via the brake shoes 92, thereby generating a braking force. As shown in FIG. 1 , two brake linings 93 are provided for each pair of brake shoes 92. A predetermined gap is provided between the two brake linings 93 provided for each brake shoe 92.

[0014] The actuating cam 94 is located between the tips of the pair of brake shoes 92. When the vehicle brakes are applied, the actuating cam 94 rotates the tips of the pair of brake shoes 92 outward. This presses the brake linings 93 against the inner circumferential surface of the brake drum 91, and the frictional force generated between the brake linings 93 and the brake drum 91 brakes the rotation of the brake drum 91. Note that a configuration including a wedge or the like may be used instead of the actuating cam 94.

[0015] The return spring 95 is connected between the tip ends of the pair of brake shoes 92. The return spring 95 biases the tip ends of the pair of brake shoes 92 inward. When the brakes are not being applied, the return spring 95 holds the pair of brake shoes 92 in positions where they have rotated inward. The brake lining 93 is held in a position away from the inner circumferential surface of the brake drum 91 because the pair of brake shoes 92 are held in positions where they have rotated inward by the biasing force of the return spring 95.

[0016] As shown in FIG. 2, the temperature detection device 10 has a temperature sensor 20 and a sensor mounting portion 30. The temperature sensor 20 detects the temperature of the brake shoe 92. The temperature sensor 20 is configured to include, for example, a sheathed thermocouple. In this case, the temperature sensor 20 measures the temperature environment using a minute potential difference due to the so-called Seebeck effect. The temperature sensor 20 has a sheath 21, a compensation conductor 22, and a sleeve 23. The sheath 21 forms the tip side of the temperature sensor 20. As shown in FIGS. 2 to 4, the sheath 21 has a sheath body 211, a pair of core wires 212, and a sheath insulator 213. The sheath body 211 is made of, for example, metal and is configured as a tubular member with a closed tip.

[0017] The pair of core wires 212 are made of, for example, metal wire or alloy wire. A portion of the core wire 212, including its tip end, is housed inside the sheath body 211. The pair of core wires 212 are connected to each other at their tip ends to form a temperature measuring junction (not shown). As shown in FIG. 3, the base end side of the core wire 212 is exposed from the inside of the sheath body 211 inside the sleeve 23. The sheath insulator 213 is provided inside the sheath body 211 and electrically insulates the sheath body 211 from the core wire 212. The sheath insulator 213 is, for example, an inorganic insulator such as magnesium oxide. The outer periphery of the core wire 212 may be covered with an insulator (not shown).

[0018] The compensating conductor 22 is located on the base end side of the temperature sensor 20. The compensating conductor 22 is connected to the sheath 21. As shown in FIG. 3, the compensating conductor 22 has a coating 221 and a pair of conductors 222. The coating 221 forms the outer surface of the compensating conductor 22. The coating 221 is made of a heat-resistant synthetic resin, such as fluororesin. Heat resistance means the ability to withstand high temperatures of approximately 200°C, which is the operating environment of the temperature sensor 20. The pair of conductors 222 is made of, for example, a metal wire or an alloy wire. The outer periphery of the conductor 222 is coated with an insulator (not shown). The base end side of the conductor 222 is provided inside the coating 221. The tip side of the conductor 222 is exposed from the inside of the coating 221 inside the sleeve 23, as shown in FIG. 3.

[0019] The sleeve 23 is made of an engineering plastic such as polyphenylene sulfide and is configured as a tubular member with both ends open. The sleeve 23 covers the entire circumference of the base end side of the sheath 21 and the tip end side of the compensation conductor 22. As shown by the double-dashed line in FIG. 3 , the pair of core wires 212 and the pair of conductors 222 are connected inside the sleeve 23 via, for example, a crimping metal fitting (not shown). In other words, the sleeve 23 covers the entire circumference of the connection portion 24 between the pair of core wires 212 and the pair of conductors 222. In this case, the sleeve 23 is formed by molding so as to cover the connection portion 24. The sleeve 23 ensures heat resistance at the connection portion 24.

[0020] The sensor mounting portion 30 is used to attach the temperature sensor 20 to the brake shoe 92. Specifically, the sensor mounting portion 30 is used to attach the temperature sensor 20 to the inner peripheral surface of the rim portion 922. The sensor mounting portion 30 is made of, for example, a member formed by bending and processing a metal plate. The sensor mounting portion 30 is detachably attached to the rim portion 922, for example, by sandwiching the rim portion 922 therebetween.

[0021] The sensor mounting portion 30 has a mounting portion main body 31 and a holding portion 32. The mounting portion main body 31 constitutes the main body of the sensor mounting portion 30. The mounting portion main body 31 is formed, for example, in a substantially L-shape. The mounting portion main body 31 has a cover portion 311 and a through hole 312. As shown in FIG. 2 , the cover portion 311 is a member that covers the outer periphery of the sheath 21 near the tip end, thereby fixing the vicinity of the tip end of the sheath 21. The through hole 312 is formed by penetrating the mounting portion main body 31 in the thickness direction. The through hole 312 corresponds to the tip end side of the sheath 21. The tip end side of the sheath 21, in this case a region including the temperature measuring junction, faces the inner circumferential surface of the rim portion 922 via the through hole 312.

[0022] The holding portion 32 is provided at one end of the mounting portion main body 31. The holding portion 32 is provided at the end opposite to the side attached to the rim portion 922 of the sensor mounting portion 30. The holding portion 32 is capable of holding part of the temperature sensor 20. As shown in FIG. 2, the holding portion 32 has two recessed portions 321. The two recessed portions 321 are provided at positions spaced apart from each other and are configured so that the sheath 21 and compensation conductor 22 located near the sleeve 23 of the temperature sensor 20, in this case near both ends of the sleeve 23, can be hung thereon.

[0023] Here, since sleeve 23 is formed of a tubular member with both ends open as described above, a minute gap 231 is formed between one end of sleeve 23, in this case the distal end, and sheath 21, as shown in Fig. 4. That is, gap 231 is located between the inner surface of sleeve 23 and the outer surface of sheath 21. Meanwhile, a minute gap 232 is formed between the other end of sleeve 23, in this case the proximal end, and compensation lead wire 22, as shown in Fig. 5. That is, gap 232 is located between the inner surface of sleeve 23 and the outer surface of compensation lead wire 22. In the following description, gap 231 may be referred to as the distal end gap 231, and gap 232 may be referred to as the proximal end gap 232.

[0024] The inside of the brake drum 91 of the drum brake 90 may be exposed to a wet environment when driving in the rain or when the vehicle is washed, etc. In this case, if water seeps into the inside of the sleeve 23 through the gaps 231, 232 between the sleeve 23 and the sheath 21 and between the sleeve 23 and the compensation conductor 22, a short circuit, i.e., a decrease in insulation resistance, may occur at the connection part 24, and the function of the temperature sensor 20 may be impaired.

[0025] Therefore, in this embodiment, the temperature sensor 20 has a sealing member 25. The sealing member 25 blocks water from entering the inside of the sleeve 23 from the distal gap 231 and the proximal gap 232. The sealing member 25 is applied to the entire inner surface of the sleeve 23, and seals the distal gap 231 and the proximal gap 232. The sealing member 25 is made of a heat-resistant adhesive, such as a room-temperature curing silicone adhesive.

[0026] Furthermore, if the covering portion 221 of the compensation conductor 22 is made of a material such as fluororesin, sufficient adhesive affinity with the sealing member 25 may not be ensured. Therefore, the temperature sensor 20 may be configured to include a binding member 26. The binding member 26 is made of, for example, a heat-shrinkable tube, and is intended to maintain the degree of adhesion of the sealing member 25 to the covering portion 221 of the compensation conductor 22. The binding member 26 is provided so as to cover the outer periphery of the sealing member 25. As shown in FIG. 5 , on the proximal side of the sleeve 23, the sealing member 25 is applied to the outer surface of the compensation conductor 22 from the end of the proximal side of the sleeve 23 outward, that is, over a predetermined length L toward the proximal side of the compensation conductor 22. The predetermined length L is, for example, within a range of 10 mm to 20 mm.

[0027] The binding member 26 covers an area including the end of the sealing member 25 applied to the outer surface of the compensation conductor 22 opposite the end located on the sleeve 23 side, i.e., the base-end end. This makes it possible to further prevent water from entering the sleeve 23 from the base-end gap 232. The binding member 26 may be arranged so as to straddle the base-end end of the sleeve 23 and the sealing member 25. Alternatively, the binding member 26 may be configured so as to be covered from the outer periphery with a heat-resistant tape member so as to straddle the base-end end of the sleeve 23, the sealing member 25, and the binding member 26. This makes it possible to improve the maintenance of adhesion of the sealing member 25 to the sleeve 23.

[0028] According to the embodiment described above, the temperature detecting device 10 is provided on the brake shoe 92 of the drum brake 90 of a vehicle. The temperature detecting device 10 includes a temperature sensor 20. The temperature sensor 20 detects the temperature of the brake shoe 92. The temperature sensor 20 includes a sheath 21, a compensation lead 22, a sleeve 23, and a sealing member 25. The sheath 21 houses a core wire 212 therein. The compensation lead 22 is connected to the core wire 212. The sleeve 23 covers a connection portion 24 between the core wire 212 and the compensation lead 22. The sealing member 25 blocks water from entering between the inner surface of the sleeve 23 and the outer surface of the sheath 21 and the outer surface of the compensation lead 22. This makes it possible for the sealing member 25 to prevent water from entering the inside of the sleeve 23. This improves the reliability of the temperature detecting device 10.

[0029] The sealing member 25 is made of a heat-resistant adhesive and is applied to the entire inner periphery of the sleeve 23. This makes it possible to easily ensure waterproofness and heat resistance around the sleeve 23 while suppressing an increase in the number of parts and reducing costs. As a result, the reliability of the temperature detection device 10 can be improved.

[0030] The sealing member 25 is a room temperature curing silicone adhesive, which ensures waterproofing around the sleeve 23 in the drum brake 90, which is exposed to a high temperature environment.

[0031] Sealing member 25 is applied to the outer surface of compensation conductor 22 over a predetermined length L extending outward from the end of sleeve 23. Temperature detecting device 10 further includes binding member 26. Binding member 26 covers an area including the end of sealing member 25 applied to the outer surface of compensation conductor 22 opposite to the end located on the sleeve 23 side.

[0032] This ensures that the sealing member 25 adheres tightly to the outer surface of the compensation conductor 22 by the fastening force of the fastening member 26, and prevents water from entering the sleeve 23 from the interface between the compensation conductor 22 and the sealing member 25. It also allows for more freedom in selecting the material of the compensation conductor 22.

[0033] (Second embodiment) Next, a second embodiment will be described with reference to Fig. 6. In this second embodiment, the temperature sensor 20 differs from the first embodiment in that it includes a sealing member 27 instead of the sealing member 25. Specifically, in this embodiment, the sealing member 27 includes a cylindrical member 271 and an elastic seal member 272.

[0034] The cylindrical member 271 is made of, for example, engineering plastic, and is configured as a cylindrical member with open ends. The cylindrical member 271 is configured so as to be able to house the sleeve 23 inside. In other words, the length of the cylindrical member 271 is longer than the length of the sleeve 23. The elastic seal members 272 are provided at the openings at both ends of the cylindrical member 271, respectively. The elastic seal members 272 are configured, for example, by O-rings. The elastic seal members 272 are arranged so as to seal gaps between the inner surface of the cylindrical member 271 and the outer surface of the sheath 21 and the outer surface of the compensation conductor 22.

[0035] According to the second embodiment, the same effects as those of the first embodiment can be achieved. Furthermore, the sleeve 23 can be protected by being housed inside the sealing member 27. This allows for greater freedom in selecting the material of the sleeve 23.

[0036] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure. [Explanation of symbols]

[0037] 10...Temperature detection device, 20...Temperature sensor, 21...Sheath, 212...Core wire, 22...Compensating lead wire, 23...Sleeve, 24...Connection part, 25, 27...Sealing member, 90...Drum brake, 92...Brake shoe

Claims

1. A temperature detection device (10) provided on a brake shoe (92) of a drum brake (90) of a vehicle, A temperature sensor (20) is provided for detecting the temperature of the brake shoe, The temperature sensor a sheath (21) that accommodates a core wire (212) therein; a compensation conductor (22) connected to the core wire; a sleeve (23) covering a connection portion (24) between the core wire and the compensation conductor; and a sealing member (25, 27) that blocks water from entering between the inner surface of the sleeve and the outer surface of the sheath and the outer surface of the compensation conductor. Temperature detection device.

2. The sealing member is applied to the entire inner surface of the sleeve and is made of a heat-resistant adhesive. The temperature detection device according to claim 1 .

3. The sealing member is a room temperature curing silicone adhesive. The temperature detection device according to claim 2 .

4. the sealing member is applied to the outer surface of the compensation conductor over a predetermined length from the end of the sleeve outward, The compensation conductor further includes a binding member (26) that covers an area including an end portion of the sealing member applied to the outer surface of the compensation conductor opposite to the end portion located on the sleeve side. The temperature detection device according to claim 2 .

Images