Relay control device, electronic control device, and relay temperature detection method

Abstract

To provide a relay control device capable of directly monitoring the temperature inside a relay without increasing the number of components.SOLUTION: A relay control device 1 is configured to control the drive of a relay 2 that opens and closes contacts 7 and 8 by energizing a coil 3, and control the energization of the coil 3 according to the coil temperature detected by the amount of energization to the coil 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a relay control device that controls the drive of a mechanical relay (hereinafter simply referred to as a "relay"), an electronic control device including the relay control device, and a relay temperature detection method that detects the internal temperature of the relay. [Background technology]

[0002] Conventionally, there is known a relay control device that controls the drive of a relay. A relay opens and closes a contact by passing current through a coil, thereby switching current through a load. When the temperature of the relay reaches a predetermined temperature of 0°C or lower, the relay control device executes control to reduce the amount of current passing through the coil. This suppresses the evaporation of moisture inside the relay case, thereby preventing condensation and freezing on the contact after current is stopped from passing through the coil.

[0003] The relay control device described in Patent Document 1 includes a relay mounted on an aluminum substrate and a thermistor mounted on the substrate as a temperature sensor. This relay control device monitors the temperature around the relay with the temperature sensor, and when the temperature falls below -5°C, it executes control to reduce the amount of current flowing to the coil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-18927 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the relay control device described in Patent Document 1 requires a temperature sensor to monitor the temperature around the relay, and an aluminum board that transfers heat from the relay to the temperature sensor. Therefore, this relay control device has problems such as an increase in the number of parts, an increase in size, and an increase in manufacturing costs. Furthermore, since the temperature sensor monitors the temperature around the relay, not the temperature inside the relay, there is also a problem that the accuracy of the current control to the coil is deteriorated.

[0006] In view of the above, an object of the present invention is to provide a relay control device, an electronic control device, and a relay temperature detection method that are capable of directly detecting the temperature inside a relay without increasing the number of parts. [Means for solving the problem]

[0007] In order to achieve the above object, according to the invention described in claim 1, a relay control device that controls the drive of a relay (2) that opens and closes contacts (7, 8) by energizing a coil (3) is configured to control energization to the coil in response to a coil temperature detected from the amount of energization to the coil. The resistance temperature coefficient for the resistance value of a coil provided in the relay is stored, and the coil temperature is calculated based on the amount of current flowing through the coil and the resistance temperature coefficient, so that the resistance temperature coefficient can be corrected according to the relay.

[0008] According to this, the relay control device detects the coil temperature from the amount of current flowing through the coil of the relay by utilizing the configuration of a conventional relay as is. The coil temperature corresponds to the temperature inside the relay. Therefore, this relay control device does not require the temperature sensor described in Patent Document 1 or an aluminum board structure for transferring heat from the relay to the temperature sensor in order to detect the temperature inside the relay, and therefore it is possible to prevent an increase in the number of parts. Furthermore, since this relay control device can directly monitor the temperature inside the relay, it is possible to accurately control the current flowing through the coil.

[0009] In addition, claims 4The present invention relates to an electronic control device including a relay control device as set forth in claim 1 etc. The electronic control device includes a printed circuit board (4) on which wiring is provided, a relay (2) mounted on the printed circuit board and configured to open and close contacts (7, 8) by energizing a coil (3), and a relay control device (1) for controlling the operation of the relay.

[0010] According to this, the electronic control device can also achieve the same effects as those of the invention according to claim 1 and the like.

[0011] In addition, claims 5 The present invention relates to a relay temperature detection method for detecting the internal temperature of a relay (2) that opens and closes contacts (7, 8) by energizing a coil (3) using a relay control device (1) configured as a microcomputer. The relay temperature detection method includes the following steps: Calculating coil resistance from a voltage value and a current value when energizing the coil (S10). Coil resistance and relay control device Memory Calculating the coil temperature based on the resistance temperature coefficient stored in advance (S20). Correcting the resistance temperature coefficient pre-stored in the memory according to the relay.

[0012] According to this relay temperature detection method, it is possible to detect the coil temperature from the amount of current flowing through the coil of the relay by utilizing the conventional relay configuration as is. The coil temperature corresponds to the temperature inside the relay. Therefore, there is no need for a temperature sensor to detect the temperature inside the relay, or a board structure to transfer heat from the relay to the temperature sensor, so an increase in the number of parts can be prevented. Furthermore, according to this relay temperature detection method, the temperature inside the relay can be directly monitored.

[0013] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0014] [Figure 1]1 is a cross-sectional view of an electronic control device including a relay control device according to an embodiment. [Diagram 2] 1 is a graph showing the relationship between coil resistance and coil temperature in a number of relays. [Diagram 3] 4 is a flowchart of a process for controlling current supply to a coil, which is executed by the relay control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (One embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, a relay control device 1 of this embodiment is an integrated circuit (IC) configured as a microcomputer, and controls the driving of a relay 2 by energizing a coil 3 of the relay 2. The relay control device 1 and the relay 2 are both mounted on a printed circuit board 4, and constitute an electronic control device 5. The electronic control device 5 is mounted on, for example, a vehicle and is used to drive electric components such as a motor (not shown) installed in the vehicle.

[0016] The relay control device 1 includes a processor that performs control processing and arithmetic processing, and a memory that stores programs, data, and the like. The processor is composed of a CPU and an MPU. The memory includes various non-transient tangible storage media such as ROM, RAM, and non-volatile rewritable memory. The relay control device 1 is configured such that the processor executes a program stored in the memory to control the energization of the coil 3 of the relay 2. The energization control of the coil 3 performed by the relay control device 1 will be described later.

[0017] The relay 2 driven and controlled by the relay control device 1 of this embodiment is a mechanical relay including a relay case 6, a coil 3, a fixed contact 7, and a movable contact 8. The relay 2 is also called an electromagnetic relay.

[0018] The relay case 6 has an upper case 10 and a base 11. The upper case 10 is formed in a cylindrical shape with a bottom. The base 11 is provided so as to close an opening provided on the substrate 4 side of the upper case 10. An accommodation space is provided inside the relay case 6 for accommodating the coil 3, the fixed contact 7, the movable contact 8, etc.

[0019] The coil 3 is an electromagnetic coil in which a linear conductor covered with a coating (i.e., a coil wire) is wound around a bobbin 12. A fixed iron core 13 is provided at the center of the bobbin 12. One end and the other end of the coil wire are electrically connected to two coil terminals 14. The two coil terminals 14 are fixed to the base 11 and protrude from the inside to the outside of the relay case 6. Note that one of the two coil terminals 14 is not shown in FIG. 1.

[0020] The fixed contact 7 is fixed to a first load terminal 15. The first load terminal 15 is fixed to the base 11, and protrudes from the inside of the relay case 6 to the outside.

[0021] The movable contact 8 is disposed at a position facing the fixed contact 7, and is fixed to a metal leaf spring 16. The leaf spring 16 is fixed to a yoke 17, and has an elastic force in a direction in which the movable contact 8 moves away from the fixed contact 7. A movable iron piece 18 is provided on the leaf spring 16 at a position facing the end 13a of the fixed iron core 13. The leaf spring 16 is electrically connected to a second load terminal 19. The second load terminal 19 is fixed to the base 11, and protrudes outside the relay case 6.

[0022] The two coil terminals 14, the first load terminal 15, and the second load terminal 19 are inserted into through holes 20, 21, and 22 provided in the printed circuit board 4, respectively, and fixed by soldering. The two coil terminals 14 are electrically connected to the relay control device 1 via wiring (not shown) provided on the printed circuit board 4. Meanwhile, the first load terminal 15 and the second load terminal 19 are electrically connected to wiring or a bus bar (not shown) through which a large current flows. The first load terminal 15 and the second load terminal 19 are electrically connected to electrical components such as a battery and a motor (not shown) via wiring or a bus bar.

[0023] In the above-mentioned configuration, when current is applied to the coil 3 from the coil terminal 14 via the wiring of the printed circuit board 4 under the control of the relay control device 1, a magnetic field is generated in the coil 3, and the coil 3 and the fixed iron core 13 are magnetized to become an electromagnet. Therefore, the movable iron piece 18 is magnetically attracted to the fixed iron core 13 side against the elastic force of the leaf spring 16, and the movable contact 8 and the fixed contact 7 come into contact (i.e., the contacts are closed). As a result, a large current flows through an electric circuit including the first load terminal 15, the fixed contact 7, the movable contact 8, the leaf spring 16, the second load terminal 19, and electric components (not shown) electrically connected to the first load terminal 15 and the second load terminal 19. Therefore, the electric components (not shown) are driven.

[0024] On the other hand, when the current to the coil 3 is stopped by the control of the relay control device 1, the magnetic field of the coil 3 disappears, and the elastic force of the leaf spring 16 separates the movable contact 8 and the fixed contact 7 (i.e., the contacts open). This cuts off the large current flowing through the electric circuit including the first load terminal 15, the fixed contact 7, the movable contact 8, the leaf spring 16, the second load terminal 19, and electric components (not shown). Therefore, the operation of the electric components (not shown) stops.

[0025] When the contacts (i.e., the fixed contact 7 and the movable contact 8) are closed by energizing the coil 3 of the relay 2, a current flows through each component of the relay 2, and the temperature inside the relay case 6 rises. When the temperature inside the relay case 6 rises, moisture evaporates, and the humidity inside the relay case 6 may increase.

[0026] Thereafter, when the current to the coil 3 is stopped, the contacts 7 and 8 open, the current flowing through each component of the relay 2 is also cut off, and the temperature inside the relay case 6 gradually drops. Here, the fixed contact 7 and the movable contact 8 are connected to metal materials with large heat capacity such as wiring and bus bars outside the relay case 6 via the first load terminal 15 and the second load terminal 19, respectively. Therefore, when the current to the coil 3 is stopped, the temperature of at least one of the fixed contact 7 and the movable contact 8 drops in a shorter time than the temperature inside the relay case 6 due to heat dissipation of the metal materials connected to the first load terminal 15 and the second load terminal 19. As a result, condensation may occur on at least one of the fixed contact 7 and the movable contact 8 due to the difference between the temperature inside the relay case 6 and the temperature inside the relay case 6 and the temperature inside the relay case 6.

[0027] If the environmental temperature in which relay 2 is used is below freezing, and condensation forms on at least one of the fixed contacts 7 and the movable contacts 8 and freezes, there is a risk of a malfunction in which the fixed contacts 7 and the movable contacts 8 do not make contact (i.e., do not conduct electricity) the next time current is applied to coil 3.

[0028] Therefore, the relay control device 1 of the present embodiment directly detects (monitors) the temperature inside the relay case 6, and executes control to adjust the amount of current supplied to the coil 3 in accordance with the detected temperature.

[0029] First, a method for detecting the temperature inside the relay case 6 by the relay control device 1 will be described with reference to the graph of FIG.

[0030] In the graph of Fig. 2, the horizontal axis indicates the resistance of the coil 3 (hereinafter referred to as "coil resistance"), and the vertical axis indicates the temperature of the coil 3 (hereinafter referred to as "coil temperature"). Solid lines A and B in Fig. 2 show the relationship between the coil resistance and the coil temperature for two types of relays 2 having different configurations such as the number of turns, wire diameter, size, and shape of the coil 3. The relationship between the coil resistance and the coil temperature is expressed by the following formula 1.

[0031] Coil temperature = coil resistance × resistance temperature coefficient (Equation 1) That is, the coil temperature has a linear relationship with the coil resistance. Note that the resistance temperature coefficient in the above formula 1 is a value that differs depending on the type or individual relay 2.

[0032] Here, it can be said that the temperature of the coil 3 provided in the relay case 6 is substantially the same as the temperature inside the relay case 6. Therefore, the relay control device 1 can directly detect the temperature inside the relay case 6 by using the coil 3 as a resistance temperature detector based on the coil resistance measured when a current is applied to the coil 3.

[0033] The coil resistance has the relationship expressed by the following equation 2. Coil resistance = coil voltage / coil current (Equation 2)

[0034] That is, based on the above formula 2, when the relay control device 1 performs constant current control on the current supply to the coil 3, it can monitor the coil voltage value and derive the coil resistance. On the other hand, when the relay control device 1 performs constant voltage control on the current supply to the coil 3, it can monitor the coil current value and derive the coil resistance.

[0035] The relay control device 1 of the present embodiment controls the amount of current supplied to the coil 3 in accordance with the temperature of the coil 3 (that is, the temperature inside the relay case 6) detected by the above-mentioned method.

[0036] Next, a process for controlling the energization of the coil 3, which is executed by the relay control device 1 of this embodiment, will be described with reference to a flowchart of FIG.

[0037] This current supply control process is executed simultaneously with the current supply from the relay control device 1 to the coil 3. First, in step S10, the relay control device 1 calculates the coil resistance from the voltage value and current value when current is applied to the coil 3, based on the above formula 2.

[0038] Next, in step S20, the relay control device 1 calculates the coil temperature based on the above formula 1 from the coil resistance calculated in step S10 and the resistance temperature coefficient pre-stored in the memory of the relay control device 1. The resistance temperature coefficient of the coil 3 is found for each relay 2 by experiment or the like and is pre-stored in the memory of the relay control device 1.

[0039] Next, in step S30, the relay control device 1 controls the supply of current to the coil 3 in accordance with the coil temperature. For example, the relay control device 1 may execute control to reduce the amount of current supplied to the coil 3 when the temperature inside the relay case 6 is a predetermined temperature of 0° C. or less. This suppresses evaporation of moisture contained in the coating of the coil 3 in a predetermined temperature environment of 0° C. or less where icing may occur inside the relay case 6, thereby preventing condensation and icing on the contacts 7 and 8 after the supply of current to the coil 3 is stopped.

[0040] Of the above-described power supply control process, the processes in steps S10 and S20 correspond to a "relay temperature detection method" recited in the claims.

[0041] The relay control device 1, the electronic control device 5, and the relay temperature detection method according to the present embodiment described above provide the following advantageous effects. (1) The relay control device 1 of the present embodiment is configured to control the supply of current to the coil 3 in response to the coil temperature detected from the amount of current flowing through the coil 3. According to this, the relay control device 1 detects the coil temperature from the amount of current flowing through the coil 3 of the relay 2 by utilizing the configuration of a conventional relay as is. The coil temperature corresponds to the temperature inside the relay case 6. Therefore, the relay control device 1 of this embodiment does not require the temperature sensor described in the above Patent Document 1 or an aluminum board structure for transferring heat from the relay to the temperature sensor, and therefore it is possible to prevent an increase in the number of parts. Furthermore, the relay control device 1 of this embodiment can directly monitor the temperature inside the relay case 6, and therefore it is possible to accurately control the current flowing through the coil 3.

[0042] (2) The relay control device 1 of the present embodiment stores the resistance temperature coefficient of the coil 3 provided in the relay 2, and calculates the coil temperature based on the amount of current flowing through the coil 3 and the resistance temperature coefficient. According to this, by pre-storing the resistance temperature coefficient of the coil 3 of each relay 2, the relay control device 1 can calculate the coil temperature based on the coil resistance calculated from the amount of current flowing through the coil 3 and the resistance temperature coefficient.

[0043] (3) The relay control device 1 of the present embodiment calculates the coil temperature based on the voltage value, current value, and resistance temperature coefficient when a current is applied to the coil 3. According to this, the relay control device 1 can calculate the coil resistance based on the voltage value and current value when current is applied to the coil 3, and can calculate the coil temperature based on the coil resistance and the resistance temperature coefficient.

[0044] (4) The relay control device 1 of the present embodiment is mounted on a printed circuit board 4 together with the relay 2, and is configured to pass electricity through the coil 3 via wiring provided on the printed circuit board 4. This allows the wiring of the board 4 connecting the relay control device 1 and the coil 3 to be short. Therefore, the relay control device 1 is able to accurately detect the coil temperature without being affected by changes in wiring resistance due to temperature. Furthermore, the relay control device 1 does not require a board structure (e.g., an aluminum board) for transferring heat from the relay 2 to the temperature sensor as described in Patent Document 1, and therefore it is possible to prevent an increase in manufacturing costs.

[0045] (5) The electronic control device 5 of this embodiment includes a printed circuit board 4 on which wiring is provided, a relay 2 mounted on the printed circuit board 4, and a relay control device 1 that controls the driving of the relay 2. According to this, the electronic control device 5 of this embodiment also does not require the temperature sensor described in the above Patent Document 1, nor a board structure for transferring heat from the relay to the temperature sensor, so that it is possible to prevent an increase in the number of parts. Furthermore, since the relay control device 1 is configured to directly monitor the temperature inside the relay case 6, it is possible to precisely control the current supply to the coil 3.

[0046] (6) The relay temperature detection method of this embodiment includes the following steps: Calculating the coil resistance from the voltage value and current value when current is applied to the coil 3 (S10); Calculating the coil temperature from the coil resistance and a resistance temperature coefficient pre-stored in the relay control device 1 (S20). According to this method, it is possible to detect the coil temperature from the amount of current flowing through the coil 3 of the relay 2 by utilizing the conventional relay configuration as is. Therefore, it is not necessary to provide a temperature sensor for detecting the coil temperature or a board structure for transferring heat from the relay to the temperature sensor, so it is possible to prevent an increase in the number of parts. Furthermore, according to this method, the temperature inside the relay case 6 can be directly monitored.

[0047] (Other embodiments) (1) In the above embodiment, the relay control device 1 stores in advance in a memory a resistance temperature coefficient determined by an experiment or the like for each relay 2, but this is not limited to the above. The relay control device 1 may be configured to be able to correct the resistance temperature coefficient stored in advance in the memory for each relay 2, for example, at the time of product shipment or maintenance. In this way, the relay control device 1 can accurately detect the coil temperature of each relay 2 by correcting the resistance temperature coefficient in accordance with the variation in the characteristics of the coil resistance and coil temperature in each relay 2.

[0048] (2) In the above embodiment, the relay control device 1 controls the energization of the coil 3 based on the coil temperature (i.e., the temperature inside the relay case 6), but this is not limited to the above. The relay control device 1 may control the energization of the coil 3 while also referring to temperature information obtained from a temperature sensor provided inside its own electronic control device 5 or in another location. In this way, the amount of energization to the coil 3 can be reduced based on the temperature difference between the inside and outside of the relay case 6 when conditions are such that condensation is likely to occur at the contacts of the relay 2, thereby suppressing the generation of water vapor.

[0049] (3) In the above embodiments, the relay control device 1 has been described as controlling the drive of the relay 2 of a type mounted on a circuit board, but this is not limited thereto. The relay control device 1 may, for example, control the drive of a plug-in relay. In this case, it is sufficient to detect the temperature of the coil 3 of the plug-in relay, excluding the effect of the resistance of the wire harness that is calculated based on the environmental temperature in which the wire harness that connects the relay control device 1 and the plug-in relay is installed.

[0050] As described above, the present invention is not limited to the above-mentioned embodiment, and can be appropriately modified within the scope of the claims. Moreover, the above-mentioned embodiments are not unrelated to each other, and can be appropriately combined, except when the combination is clearly impossible. Moreover, in each of the above-mentioned embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered to be essential in principle. Moreover, in each of the above-mentioned embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiment are mentioned, they are not limited to the specific numbers, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. Moreover, in each of the above-mentioned embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc., except when it is specifically stated that they are essential or when it is clearly limited to a specific shape, positional relationship, etc. in principle.

[0051] In the above embodiment, when it is described that external environment information of the vehicle (for example, temperature outside the vehicle) is acquired from a sensor, it is also possible to eliminate the sensor and receive the external environment information from a server or cloud outside the vehicle. Alternatively, it is also possible to eliminate the sensor and acquire related information related to the external environment information from a server or cloud outside the vehicle, and estimate the external environment information from the acquired related information.

[0052] The control unit and the method according to the present invention may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method according to the present invention may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method according to the present invention may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer. [Explanation of symbols]

[0053] 1 Relay control device 2 Relay 3 Coil 4 Printed circuit board 5. Electronic control device 7 Fixed contacts 8 moving contacts

Claims

1. A relay control device controls the drive of a relay (2) that opens and closes contacts (7, 8) by energizing a coil (3), The power supply to the coil is controlled in response to a coil temperature detected based on an amount of power supplied to the coil, A resistance temperature coefficient for a resistance value of the coil provided in the relay is stored, A coil temperature is calculated based on the amount of current flowing through the coil and the resistance temperature coefficient, A relay control device configured to be able to correct the resistance temperature coefficient in accordance with the relay.

2. 2. The relay control device according to claim 1, wherein the coil temperature is calculated based on a voltage value, a current value when a current is passed through the coil, and the resistance temperature coefficient.

3. 3. The relay control device according to claim 1, which is mounted on a printed circuit board together with the relay, and configured to energize the coil via wiring provided on the printed circuit board.

4. A printed circuit board (4) provided with wiring; The relay (2) is mounted on the printed circuit board and opens and closes the contacts (7, 8) when current is passed through the coil (3); An electronic control device comprising: the relay control device (1) according to any one of claims 1 to 3, which controls driving of the relay.

5. A relay temperature detection method for detecting an internal temperature of a relay (2) that opens and closes contacts (7, 8) by energizing a coil (3) using a relay control device (1) configured as a microcomputer, comprising: Calculating a coil resistance from a voltage value and a current value when a current is applied to the coil (S10); Calculating a coil temperature based on the coil resistance and a resistance temperature coefficient pre-stored in a memory of the relay control device (S20); and correcting the resistance temperature coefficient pre-stored in the memory in accordance with the relay.

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