Temperature switch and method for adjusting a temperature switch

Abstract

The invention relates to a temperature switch comprising a housing (2), a switching system (3) consisting of a first support (3.1) with a fixed contact (3.2) and a second support (3.3), on which a switch spring (3.4) with a switch contact (3.5) is arranged and a switching arrangement (4), which effects a positional change of the switch contact (3.5) as a function of the temperature.

Claims

1. A temperature switch, comprising a housing (2), a switching system (3) consisting of a first support (3.1) with a fixed contact (3.2) and a second support (3.3), on which a switch spring (3.4) with a switch contact (3.5) is arranged, and a switching arrangement (4), which effects a positional change of the switch contact (3.5) as a function of the temperature, wherein the first and second supports (3.1, 3.3) are bendable, the housing (2) is formed by at least one first housing section (2.1) having at least one housing opening (2.3) and a second housing section (2.2) closing the housing opening (2.3), the first and second supports (3.1, 3.3) are accessible via the housing opening (2.3) by adjustment means (10, 11), the housing opening (2.3) is at an end of the first housing section (2.1), the first housing section (2.1) at least partially houses the switching arrangement (4), the first and second supports (3.1, 3.3) extend laterally into an interior (2.1.1) in the first housing section (2.1), the first housing section (2.1) has two side sections (2.1.2, 2.1.2) located opposite to each other, on which a projection (6, 6) is formed in each case, each projection having a projection face (6.1, 6.1) running essentially at a right angle to a vertical axis of the temperature switch (1), and each of the first and second supports (3.1, 3.3) is angled in a first bending region (3a, 3a) and rests against one of the projection faces (6.1, 6.1) via an intermediate section (3b, 3b) adjacent to the first bending region (3a, 3a) via a wide side.

2. The temperature switch according to claim 1, characterised in that the switching arrangement (4) is formed by a switching element (4.1) and a shape changing bimetallic element (4.2).

3. The temperature switch according to claim 2, characterised in that the switching element (4.1) is in operative connection with the bimetallic element (4.2) and the switch spring (3.4) in such a manner that a positional change of the switch contact (3.5) takes place when the bimetallic element (4.2) is deformed.

4. The temperature switch according to claim 1, characterised in that the first housing section (2.1) is constructed in a U-shaped or essentially U-shaped manner.

5. The temperature switch according to claim 1, wherein each projection face (6.1, 6.1) has a bending edge (6.2, 6.2) thereon.

6. The temperature switch according to claim 1, characterised in that the first and second supports (3.1, 3.3) each are formed by a strip-shaped flat material with rectangular cross section with one pair of mutually opposing, spaced apart wide and narrow sides in each case.

7. The temperature switch according to claim 1, wherein each of the first and second supports (3.1, 3.3) has a second bending region (3c, 3c), in which the respective support (3.1, 3.3) is deformed in a bending direction different from the bending direction of the first bending region (3a, 3a).

8. The temperature switch according to claim 5, wherein a distance (d) between two mutually opposite free ends of the supports (3.1, 3.3) is smaller than a width (b) of the housing opening (2.3) measured in a plane (SE) perpendicular to each of the bending edges (6.2, 6.2).

9. The temperature switch according to claim 1, wherein the switch contact (3.5) and/or the fixed contact (3.2) is constructed in a convexly curved manner on a contact surface therebetween.

10. A method for adjusting a temperature switch (1), comprising a housing (2), a switching system (3) consisting of a first support (3.1) with a fixed contact (3.2) and a second support (3.3), on which a switch spring (3.4) with a switch contact (3.5) is arranged, characterised in that a first adjustment means (10) acting on the first support (3.1) and a second adjustment means (11) acting on the second support (3.3) are introduced via a housing opening (2.3), in that at least one of the supports (3.1, 3.3) is bent in an adjustment step by force action of the adjustment means (10, 11) on these supports (3.1, 3.3) and the position and/or the spring force of the switch spring (3.4) is determined in a measurement step by a measurement means (12).

11. The method according to claim 10, wherein before the initial bending of the first or second support (3.1, 3.3), the position of the switch spring (3.4) at a switching point, at which a separation of the switch contact (3.5) from the fixed contact (3.2) takes place, is measured with reference to a reference plane by the measurement means (12).

12. The method according to claim 11, characterised in that the spring force exerted by the switch spring (3.4) onto the measurement means (12) is measured at the switching point and/or when the switch contact (3.5) rests against the fixed contact (3.2).

13. The method according to claim 10, wherein in the adjustment step, the bending of the first and/or second support (3.1, 3.3) around a bending edge (6.2, 6.2) takes place by lowering the respective adjustment means (10, 11) onto a section of the first and/or second support (3.1, 3.3) protruding over the bending edge (6.2, 6.2).

14. The method according to claim 10, characterised in that following one or a plurality of adjustment steps, a measurement step is carried out in each case for measuring the position of the switch spring (3.4) at the switching point and/or for measuring the spring force at the switching point and/or for measuring the spring force when the switch contact (3.5) rests against the fixed contact (3.2).

15. The method according to claim 10, characterised in that an iterative adjustment takes place by means of an alternating sequence of an adjustment step and a measurement step.

16. The method according to claim 10, characterised in that the bending of the at least one support (3.1, 3.3) in successive adjustment steps is differently sized.

17. The method according to claim 10, characterised in that the support(s) (3.1, 3.3) to be bent in the subsequent adjustment step and/or the degree of bending in the subsequent adjustment step are determined as a function of the change of the position of the switch spring (3.4) and/or the spring force at the switching point.

18. The method according to claim 10, characterised in that the adjustment of the temperature switch (1) takes place with respect to a switching element length chosen from a quantity of different, discrete switching element lengths.

19. The method according to one of claim 10, characterised in that the adjustment of the temperature switch (1) takes place by means of the action of the measurement means (12) on a switching element (4.1) located in the housing (2), wherein the switching element (4.1) acts on the switch spring (3.4).

Description

(1) In the following, the invention is described in more detail on the basis of exemplary embodiments in connection with the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

(2) FIG. 1 by way of example shows a temperature switch according to the invention in a sectional illustration;

(3) FIG. 2 by way of example shows a temperature switch measured by means of a measurement and adjustment arrangement in the case of an open electrical contact;

(4) FIG. 3 by way of example shows a temperature switch measured by means of a measurement and adjustment arrangement in the case of a closed electrical contact.

DETAILED DESCRIPTION OF THE INVENTION

(5) In FIG. 1, with the reference number 1 a temperature switch according to the invention is shown in a sectional illustration through the sectional plane SE. The temperature switch 1 has a housing 2 of closed construction, out of which contact elements 5, 5 are guided on the lower side 1.1 as contact element pair. A switching system 3 consisting of a first support 3.1 with a fixed contact 3.2 and a second support 3.3, on which a switch spring 3.4 with a switch contact 3.5 is arranged, is provided in the housing 2. Furthermore, a switching arrangement 4 is provided within the housing 2, which effects a positional change of the switch contact 3.5 as a function of the temperature. Here, the switching arrangement 4 acts on the switch spring 3.4 in particular and thereby effects a separation of the switch contact 3.5 from the fixed contact 3.2 by spacing these contacts with respect to one another.

(6) The housing 2 formed from an electrically insulating material is of multi-part construction and essentially consists of a first housing section 2.1 having a housing opening 2.3 and a second housing section 2.2 closing the housing opening 2.3. The housing opening 2.3 is here provided on the upper side 1.2 of the temperature switch 1 opposite the contact elements 5, 5 and is closed by the second housing section 2.2, constructed in a lid-like manner. The first housing section 2.1 is constructed in a U-shaped or essentially U-shaped manner and has a base section 2.1.3, which forms the lower side 1.1 of the temperature switch 1. The base section 2.1.3 laterally merges into the side sections 2.1.2, 2.1.2, which in their longitudinal extent protrude with respect to the base section 2.1.3 in the direction of the vertical axis HA of the temperature switch 1. The free ends of the side sections 2.1.2, 2.1.2 located remotely from the base section 2.1.3 are constructed planarly, the planar sections of these free ends spanning a reference plane BE, which runs perpendicularly to the vertical axis HA. After the production or adjustment of the temperature switch, the second housing section 2.2 rests against these planar sections of the side sections 2.1.2, 2.1.2 by means of the outer edge thereof and is connected in these regions by adhesive bonding or welding to the first housing section 2.1. An interior 2.1.1 is formed in the housing 2 by means of the protrusion of the side sections 2.1.2, 2.1.2 with respect to the base section 2.1.3 and by means of the lid-shaped construction of the second housing section 2.2, in which interior the switching arrangement 4 or the switching system 3 is housed in a protected manner.

(7) The supports 3.1, 3.3 are inserted into this interior 2.1.1 of the housing 2, specifically through passages 2.4, 2.4. In their longitudinal extent, the passages 2.4, 2.4 here run parallel to the vertical axis HA and are provided in the region between the base section 2.1.3 and the side sections 2.1.2, 2.1.2. The side section 2.1.2, 2.1.2 is constructed in a reinforced manner in the region of the passages 2.4, 2.4, i.e. it has a larger thickness of the wall. As a result, projections 6, 6 protruding into the interior 2.1.1 are formed, which in each case have an upper projection face 6.1, 6.1, which run parallel to the reference plane BE and perpendicularly to the vertical axis HA, respectively. The supports 3.1, 3.3 are designed in a strip-shaped manner and formed from an electrically conductive material. The supports 3.1, 3.3 are guided through the passages 2.4, 2.4 and shaped by bending in a permanently angled manner in a first bending region 3a, 3a, specifically in such a manner that the section of the supports 3.1, 3.3 protruding into the interior 2.1.1 rests by means of its lower side facing the base section 2.1.3 against the projection face 6.1, 6.1 by means of an intermediate section 3b, 3b in each case. The projections 6, 6 in each case additionally have a bending edge 6.2, 6.2, which are formed in the transition region between the respective projection face 6.1, 6.1 and an inner face section running parallel to the respective passages 2.4, 2.4. In the region of the bending edge 6.2, 6.2, the supports 3.1, 3.3 are in turn permanently deformed or bent in the second bending region 3c, 3c, specifically in such a manner that the supports 3.1, 3.3 are deformed in the two successive first and second bending regions 3a, 3a, 3c, 3c in different bending directions. Preferably, the supports 3.1, 3.3 are constructed in a bent manner in the first bending region 3a, 3a by 90 or essentially by 90, so that the support 3.1, 3.3 guided within the passages 2.4, 2.4 extends from a vertical course orientated parallel to the vertical axis HA after the bending region 3a, 3a in the horizontal direction, i.e. parallel to the reference plane BE at least in certain sections by means of the intermediate section 3b, 3b thereof. In the further, second bending region 3c, 3c, the respective supports 3.1, 3.3 are bent by an acute angle, preferably by an angle between 5 and 15, this angle being formed between the plane accommodating the respective projection face 6.1, 6.1 and the support 3.1, 3.3 and opening in the direction of the vertical axis HA. Here, it may be noted that the bending of the supports 3.1, 3.3 in the second bending region 3c, 3c can be differently sized and in particular can be changed independently of one another in the adjustment method described in the following. By means of the previously described construction of the supports 3.1, 3.3, these supports protrude laterally into the interior 2.1.1 constructed in the housing 2 and form tongue-like bendable sections by means of the free-end side protruding ends. The bending in this case preferably takes place around the bending edges 6.2, 6.2. The fixed contact 3.2 is provided on the lower side of the free-side end of the first support 3.1 facing the base section 2.1.3. The switch spring 3.4 is arranged on the lower side of the second support 3.3 likewise facing the base section 2.1.3, which extends beyond the free end protruding from the second support 3.3 to the first support 3.1 and is located with the switch contact 3.5 provided on the switch spring 3.4 in the region of the fixed contact 3.2.

(8) In the exemplary embodiment shown, the contact elements 5, 5 are designed as separate elements, which are connected by means of conventional connection technologies, for example by welding or soldering to the supports 3.1, 3.3. Alternatively, the contact elements 5, 5 can be formed by the free-end sides of the first and second supports 3.1, 3.3, which protrude on the lower side with respect to the housing 2.

(9) The temperature switch according to FIG. 1 is constructed as an opener, i.e. in the rest state, the switch contact 3.5 rests against the fixed contact 3.2, so that the first support 3.1 is electrically connected to the second support 3.3 via the fixed contact 3.2, the switch contact 3.5 and the switch spring 3.4. A switching arrangement 4 is provided in the temperature switch 1, which acts on the switch spring 3.4 in such a manner that, if a defined temperature threshold is exceeded, the electrical contact is opened by lifting off the switch contact 3.5 from the fixed contact 3.2. The switching arrangement 4 is here formed in the exemplary embodiment shown by a switching element 4.1 formed in a rod-shaped manner and a bimetallic element 4.2. The switching element 4.1 is here formed from a non-conductive material. The bimetallic element 4.2 is in particular constructed as a bimetallic disc, which, if a certain temperature threshold is exceeded, implements a reshaping from a concave state, curved in the direction of the upper side 1.2, to a convex state, curved in the direction of the lower side 1.1. This reshaping here takes place suddenly in a snap movement, the positional change of the bimetallic element 4.2 in the central region thereof is transmitted via the switching element 4.1, which is arranged by means of the narrow side thereof in this central region of the bimetallic element 4.2, to the switch spring 3.4, against which the switching element 4.1 rests by means of the further, opposite narrow side.

(10) The bimetallic element is arranged on the second housing section 2.2 and held by the same. The second housing section 2.2 accommodating the bimetallic element 4.2 is constructed from a material with high thermal conductivity and with low thermal mass, so that a good heat transfer, which is temporally delayed to the smallest extent possible, can take place between the second housing section 2.2 and the bimetallic element 4.2.

(11) In the following, the adjustment of the temperature switch 1 shall be described on the basis of the FIGS. 2 and 3. The adjustment takes place here during the production of the temperature switch 1 before the closure of the housing opening 2.3 by means of the second housing section 2.2. The housing opening 2.3 is constructed in such a manner that adjustment and measurement means 10, 11, 12 can be introduced into the interior 2.1.1 from the upper side 1.2 of the temperature switch. The width b of the housing opening 2.3 is here dimensioned in such a manner that the same is larger than the distance d of the free ends of the supports 3.1, 3.3 from one another in the sectional plane SE accommodating the supports 3.1, 3.3. As a result, adjustment means 10, 11 can be positioned on the regions of the supports 3.1, 3.3 protruding over the bending edges 3.2, 3.2 and the positions of these sections are changed by bending around the bending edges 3.2, 3.2.

(12) The measurement and adjustment arrangement, designated in the FIGS. 2 and 3 with the reference number 15, has a first and second adjustment means 10, 11, which are constructed slidably in a direction parallel to the vertical axis HA of the temperature switch 1 and form bearing surfaces against the supports 3.1, 3.3 on the free ends introduced into the interior 2.1.1. A measurement means 12 is provided between the first and second adjustment means 10, 11, which is likewise constructed slidably in the direction of the vertical axis HA of the temperature switch 1 and is constructed for measuring the spring force of the switch spring 3.4 or for measuring the position of the switch spring. The sliding of the adjustment and measurement means 10, 11, 12 takes place relatively to a guide and bearing element 13. The measurement and adjustment arrangement 15 is introduced into the temperature switch 1, which is open at the upper side, in such a manner that the guide and bearing element 13 comes to lie in the reference plane BE by means of its lower side 13.1, i.e. rests in certain sections against the free ends of the side sections 2.1.2, 2.1.2. In the following, the reference plane BE is used as reference plane for all measurement and adjustment steps. The aim of the previously described adjustment, inter alia, is to set the switch hysteresis of the temperature switch 1 in a targeted manner, the switch hysteresis being influenced decisively by the switch clearance, which results from the fact that the switching element is not clamped between the bimetallic element 4.2 and the switch spring 3.4 in the case of closed electrical contact between the switch contact 3.5 and the fixed contact 3.2, but rather rests against the switch spring by means of its own weight due to gravity, but is spaced from the bimetallic element 4.2 at the upper side, so that the bimetallic element 4.2 can deform slightly without a positional change of the switching element 4.1 resulting.

(13) At the beginning of the adjustment of the temperature switch 1, the determination of the switching point, at which an opening of the electrical contact between the fixed contact 3.2 and the switch contact 3.5 can be measured, and the spring force of the switch spring 3.4, specifically both in the closed state of the contact and in the open state, takes place in a first step. Here, the measurement means is guided to the switch spring 3.4 and initially the spring force in the closed state of the contact is determined.

(14) Subsequently, the pass of the measurement means 12, at which an opening of the electrical contact results, is determined by means of a continuity test between the contact elements 5, 5. The pass is determined here with reference to the reference plane BE. Finally, in a further measurement step, the spring force of the switch spring in the case of an open electrical contact is measured in a further measurement step. To do this, the measurement means 12 is lowered yet further from the switching point, in order to reproduce the switching pass of the bimetallic element 4.2. This measured spring force for an open contact corresponds to the force, which acts on the bimetallic element 4.2 in the case of an open contact and as a result significantly influences the switch hysteresis of the temperature switch 1.

(15) After determining the actual values of the spring forces or the switching point, the supports 3.1, 3.3 are bent iteratively in such a manner that the switching point, i.e. the opening of the electrical contact at a defined pass of the measurement means 12 with respect to the reference plane BE is reached and the spring forces in the closed state or in the open state also reach the desired values. The desired values depend substantially on the length of the switching element 4.1 to be used and are for example stored as a parameter set in the measurement and adjustment arrangement used. The spring forces in the closed or open contact state cannot be adjusted independently of one another. However, it is possible to set the spring force to a desired value in the case of an open contact thereby monitoring that the spring force lies in a reliable range in the case of a closed contact. As the spring force of the switch spring 3.4 acts on the bimetallic element 4.2 in the open contact state, the desired value of the spring force in the open contact state results from the desired switching temperature when closing the contact. After the first measurement of the temperature switch 1, the iterative adjustment takes place, the first and/or second support 3.1, 3.3 being bent by the first or second adjustment means 10, 11 around the bending edges 6.2, 6.2. The bending initially takes place with a small increment, i.e. only a slight bending of the supports 3.1, 3.3, as too strong a bending of the supports 3.1, 3.3 cannot be reversed without manual intervention or without a relatively large outlay. Care is therefore to be taken, that the desired values for the switching point and the spring forces are achieved whilst complying with the predetermined bending direction in the direction of the base section 2.1.3. Following the first bending of the supports 3.1, 3.3, a new measurement of the switching point or the spring forces takes place in the closed or in the open state of the electrical contact. As a result, the completed adjustment procedure can be analysed on the basis of the change of the measured parameters and the degree of bending in the subsequent adjustment step, i.e. the adjustment increment or the support 3.1 or 3.3 to be bent can be determined therefrom. Here, the degree of bending of the respective supports 3.1, 3.3 in successive adjustment steps can be differently sized.

(16) The adjustment can take place on a single, determined length of the switching element 4.1. However, it is also possible to undertake an adjustment in such a manner that the same takes place with respect to a switching element length to be chosen from a quantity of different, discrete switching element lengths, the chosen switching element length subsequently being used during the final assembly of the temperature switch 1. In addition, it is also possible that the measurement of the temperature switch 1 takes place using the switching element 4.1 to be installed in the same temperature switch 1. Here, the measurement means 12 can for example have a receptacle for the switching element 4.1. As a result, tolerances in the switching element length can already be taken into account during the adjustment and thus a more exact setting of the switching point can take place.

(17) As the bending of the support 3.1, 3.3 effects a displacement of the bearing points of the fixed contact 3.2 with respect to the switch contact 3.5, one or both contact surfaces can be constructed convexly, so that the bending of the supports 3.1, 3.3 leads to tolerable displacements of the contact bearing points. As previously stated, the setting of the switching point takes place by bending the support 3.1, the spring force, which the switch spring 3.4 has both in the closed state and in the open state, also necessarily being changed at the same time. By bending the support 3.3, a setting of the spring force of the switch spring 3.4 or a compensation of the change of the spring force takes place, which change results during the setting of the switching point. Preferably, the corresponding bending of the supports 3.1 and 3.3 takes place simultaneously, specifically under constant measurement of the feed path of the switch spring 3.4 between opening and closing and also the spring force of the switch spring 3.4 using the probe- or rod-shaped measurement means 12.

(18) The invention was previously described on the basis of an exemplary embodiment. It is understood that numerous modifications and changes are possible without departing from the inventive idea.

REFERENCE LIST

(19) 1 Temperature switch 1.1 Lower side 1.2 Upper side 2 Housing 2.1 First housing section 2.1.1 Interior 2.1.2, 2.1.2 Side section 2.1.3 Base section 2.2 Second housing section 2.3 Housing opening 2.4, 2.4 Passage 3 Switching system 3.1 First support 3.2 Fixed contact 3.3 Second support 3.4 Switch spring 3.5 Switch contact 3a, 3a First bending region 3b, 3b Intermediate section 3c, 3c Second bending region 4 Switching arrangement 4.1 Switching element 4.2 Bimetallic element 5, 5 Contact element 6, 6 Projection 6.1, 6.1 Projection face 6.2, 6.2 Bending edge 10 First adjustment means 11 Second adjustment means 12 Measurement means 13 Guide and bearing element 13.1 Lower side 15 Measurement and adjustment arrangement Angle b Width d Distance BE Reference plane HA Vertical axis SE Sectional plane