Tracked undercarriage wheel assembly with temperature monitoring

Abstract

The tracked undercarriage roller assembly (17) comprises: a roller body (18) having a through cavity (19) bounded by a radially inner surface (20); a shaft (22) inserted into the through cavity (19) of the roller body (18); a bushing (32) extending from a first axial end (32a) to a second axial end (32b) and radially interposed between the roller body (18) and the shaft (22); an annular chamber (34) at least partially filled with lubricant and radially interposed between the shaft (22) and the bushing (32); and a receiving base (37) provided within the shaft (22) with an inlet portion (39) facing the axial end face (22d) of the shaft (22) and a measuring portion (40) located within the shaft (22) at an axial position comprised between the first axial end (32a) and the second axial end (32b) of the bushing (32), the inlet portion (39) and the measuring portion (40) being aligned with each other along the axial direction. The temperature transducer 41 is mounted on a measuring portion 40 inside the receiving base 37, and the measuring portion 40 is mounted at a radial distance from the bushing 32 between 8 mm and 50 mm.

Description

[Technical Field]

[0001] The present invention relates to a tracked undercarriage roller assembly with temperature monitoring, i.e., a tracked undercarriage roller assembly whose operating temperature is monitored. [Background technology]

[0002] Tracked undercarriages are typically used on work machines, such as earthmoving machines, mining machines, demolition machines, and the like, to enable these machines to move over uneven ground or where there is little grip.

[0003] A tracked undercarriage typically includes two chain assemblies arranged parallel and spaced apart from one another and configured to receive and transmit drive torque to the ground. Each chain assembly typically includes multiple undercarriage components including a closed-loop chain on a drive wheel and on an idler wheel (or idler) operatively connected to a tensioner assembly. The undercarriage components further include multiple track roller assemblies between the drive wheel and the idler wheel configured to guide the chain during its movement. The track roller assemblies typically include one or more upper track roller assemblies and multiple lower track roller assemblies.

[0004] A chain typically comprises a number of links, where a link is a single component of the chain that is connected to other components. Typically, each link comprises a pair of plates facing each other. The links are interconnected by pins. Each pin is typically inserted into a hole in the plate and connects two links together.

[0005] The sole is usually attached to the link that is in direct contact with the ground and serves to release traction to the ground and increase the contact surface between the machine and the ground. The type of sole used depends on the ground on which the machine must operate, the environmental conditions in which the machine must operate, and the specifications proposed by the machine manufacturer.

[0006] Each roller assembly typically includes a roller body intersected by a shaft. The roller assembly is bounded by a radially inner surface facing the shaft, specifically, facing the outer surface of the shaft. The roller body is rotatable about a shaft that is fixed relative to a base carrier to which the shaft is attached. The roller assembly includes a bushing that fits on the outer surface of the shaft to interpose between the shaft and the inner surface of the roller body. The roller body and shaft are metallic, typically steel, and the bushing is configured to reduce friction between the roller body and the shaft. The bushing is typically made of a non-ferrous material, such as bronze, or a bimetallic alloy, and is lubricated to further reduce friction between the bushing contact surface and the roller body and / or between the bushing and the shaft.

[0007] The undercarriage is typically subjected to very severe operating conditions which may be derived from the overall weight of the machine, the large amount of power transmitted from the machine's engine to the ground, and / or the shape and configuration of the terrain in which the machine must operate.

[0008] In particular, the applicant has determined that operations involving moving large earthmoving machines place high stresses on several undercarriage components. A particularly critical undercarriage component is the lower track roller assembly, which functions to absorb loads transmitted from the machine and guide the chain. Typically, large excavators are provided with multiple lower track roller assemblies, e.g., 8 to 32 lower track roller assemblies. When the excavator is in operation, the lower track roller assemblies are rotated, and this rotation results in a significant increase in the internal temperature of the track roller assemblies, which may reach critical values ​​that may affect the functional integrity of these components.

[0009] Applicant has noted that improperly lubricating the bushings increases friction, which can lead to damage to the roller assembly caused by wear of the bushings, which gradually reduces in thickness, or to the bushings gripping the shaft and / or roller body.

[0010] The applicant has noticed that by measuring the bushing temperature, it is possible to determine whether there is an abnormality in the lubrication, specifically, whether the temperature of the lubricant increases as the temperature of the bushing increases.

[0011] U.S. Patent Application Publication No. 2013 / 0255354 discloses a monitoring device for an undercarriage assembly having a roller assembly including a shaft and a bushing. In one example, the monitoring device includes a temperature sensor located inside the roller assembly for measuring the temperature of the bushing. In particular, an opening is provided in the shaft, parallel to the shaft and deep enough to overlap the bushing, with an outwardly facing portion that extends to the outer surface of the shaft. The temperature sensor is inserted into the opening and positioned on the portion facing the shaft surface. The document mentions that the output signal is transmitted to a computer via a wireless transmitter or that the data is accessed through a port that connects to the monitoring device.

[0012] Applicant has determined that an opening in the shaft that reaches the outer surface of the shaft allows a temperature sensor to be positioned in direct or substantially direct contact with the bushing, effectively measuring the temperature of the bushing.

[0013] However, applicant has determined that such openings may allow lubricant to leak into the openings, which can have two drawbacks: damaging the temperature sensor and reducing the amount of lubricant available between the bushing and the shaft. In this second event, a lack or shortage of lubricant may even lead to premature deterioration of the roller assembly.

[0014] Applicant has noted that an indication of inadequate bushing lubrication may be related not only to the temperature of the bushing, but also to the temperature of the portion of the shaft located in the vicinity of the bushing.

[0015] Applicant has determined that by placing a temperature transducer within the shaft of the roller assembly so that the transducer is near the bushing but not directly facing or contacting the bushing, it is possible to measure a temperature that does not correspond exactly to the actual temperature but is proportional to the temperature of the bushing, making it possible to identify abnormal increases in bushing temperature. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] U.S. Patent Application Publication No. 2013 / 0255354 Summary of the Invention [Means for solving the problem]

[0017] The present invention provides a roller body having a through cavity bounded by a radially inner surface; a shaft inserted into a through cavity in the roller body; a bushing extending from the first axial end to the second axial end and radially interposed between the roller body and the shaft; an annular chamber at least partially filled with lubricant and radially interposed between the shaft and the bushing; a receiving base (37) obtained within the shaft, the receiving base having an inlet portion facing an axial end face of the shaft and a measuring portion located within the shaft at an axial position between the first axial end and the second axial end of the bushing, the inlet portion and the measuring portion being aligned with each other along the axial direction; a temperature transducer located in the measurement portion inside the receiving base; Equipped with The present invention relates to a tracked undercarriage roller assembly in which the measurement portion is located at a radial distance from the bushing between 8 mm and 50 mm.

[0018] By disposing the receiving base in the shaft and inserting a temperature transducer inside the measurement portion of the receiving base, it is possible to detect the temperature of the shaft at the measurement portion of the receiving base.

[0019] As is known, because the shaft of a tracked undercarriage wheel assembly is typically made of an iron alloy such as steel, the shaft has thermal conductivity such that the portion of the shaft located near the bushing can change temperature as the bushing changes temperature.

[0020] The applicant has determined that, depending on the size of the roller assembly and the actual material used to manufacture the shaft, a radial distance of the temperature between 8 and 50 millimeters from the bushing will make it possible to detect a sudden or abnormal increase in bushing temperature.

[0021] If the temperature increase detected by the temperature transducer exceeds a predetermined threshold, this can be associated with an abnormal increase in the temperature of the bushing, for example due to leakage of lubricant from the annular chamber, excessive friction of the bushing against the shaft, or in any case outside the scope of the bushing's functionality.

[0022] This allows intervention to restore functionality to the roller assembly before it is irreversibly damaged.

[0023] Furthermore, by aligning the inlet portion and the measurement portion along the axial direction and positioning the inlet portion facing the axial end face of the shaft, the accommodating base portion is obtained completely inside the shaft without having an opening facing the bushing, thereby preventing lubricant from leaking from the annular chamber toward the accommodating base portion or toward the temperature transducer.

[0024] The lubricant may be, for example, a lubricating oil or a grease.

[0025] The terms "axial," "axially," "radial," and "radially" are used with reference to the axis of rotation of the wheel assembly.

[0026] In particular, the terms "axial" and "axially" refer to a reference / quantity that is positioned / measured or extends in a direction parallel to or coincident with the axis of rotation of a wheel assembly.

[0027] The terms "radial" and "radially" refer to a reference / quantity located / measured or extending in a direction perpendicular to the axis of rotation of a wheel assembly.

[0028] The terms "radially inner" and "radially outer" refer to positions closer to or further from the axis of rotation, respectively.

[0029] The terms "axially inner / outer" refer to positions nearer and further, respectively, from points on the roller assembly disposed along the axis of rotation that are equally spaced axially from both ends.

[0030] The term "transducer" refers to a device that directly interacts with a measurand, i.e., the first element in a measurement chain that converts a physical quantity into an electrical signal related to the measurand.

[0031] Preferably, the measuring portion is located at a radial distance from the bushing between 10 and 40 mm, more preferably between 12 and 30 mm, for example about 15 mm.

[0032] Preferably, the receiving base portion is a non-penetrating cavity that is symmetrical about an axis of symmetry parallel to the axial direction.

[0033] This allows the receiving seat to be obtained by drilling the shaft to a desired depth for inserting the temperature transducer inside the shaft.

[0034] Preferably, the blind cavities have a linear extension and do not include deviations or branches radially diverging from an axially parallel axis of symmetry.

[0035] This prevents the receiving seat from reaching the radially outer surface of the shaft or directly facing the bushing or the annular chamber containing the lubricant, avoiding the possibility of lubricant leaking from the annular chamber.

[0036] Preferably, the inlet portion extends radially further than the measurement portion extends radially.

[0037] Preferably, the radial extension of the inlet portion is approximately twice the radial extension of the measurement portion.

[0038] Preferably, an electronic sensor module is provided, configured to generate a wireless mode measurement signal containing data representative of temperature, the electronic sensor module being located at the inlet portion of the receiving base.

[0039] Preferably, the electronic sensor module comprises circuit components, an electronic processor, a power source, and a wireless transmitter operatively connected to the electronic processor to receive respective measurement signals including data representative of temperature, and the wireless transmitter generates corresponding wireless mode measurement signals including data representative of temperature.

[0040] Preferably, the electronic processor of the electronic sensor module is configured to receive the measurement signal from the temperature transducer.

[0041] This allows, for example, an operator far away from the tracked vehicle incorporating the roller assembly to connect a mobile device or PC to the Wi-Fi network to which the electronic sensor module is connected and remotely view data on the current temperature of the shaft section near the bushing.

[0042] Preferably, the inlet portion includes an annular groove engaged by a retaining ring, the annular groove being axially outward of the electronic sensor module such that the electronic sensor module is maintained axially within the inlet portion by the retaining ring.

[0043] This keeps the electronic sensor module inside the receiving base, avoiding possible damage to the electronic sensor module during use of the roller assembly, and ensuring proper functioning of the electronic sensor module.

[0044] Preferably, a stopcock is provided at the inlet portion of the receiving seat, the stopcock being preferably axially interposed between the retaining ring and the electronic sensor module.

[0045] The stopcock prevents liquid, mud, dirt, dust, etc. from entering the receiving base.

[0046] Preferably, the retaining ring is removable from the annular groove in the inlet portion of the receiving seat.

[0047] A retaining ring holds the plug in the operating position, but the plug can be removed if access is required to the interior of the receiving base for inspection or replacement of the temperature transducer and / or electronic sensor module.

[0048] Preferably, the temperature transducer is wired to an electronic sensor module.

[0049] Preferably, the temperature transducer is a thermistor, the resistance of which decreases as the temperature increases.

[0050] As the temperature of the shaft near the bushing increases, the resistance of the thermistor decreases, so that if the thermistor fails (for example, if there is a dielectric breakdown between the thermistor and the electronic sensor module), the detected resistance will deviate significantly from the expected resistance, providing a rapid indication of thermistor failure.

[0051] Preferably, a pin inserted into the radial cavity of the shaft is provided to unite the shaft with the undercarriage frame, and the receiving seat does not intersect with the radial cavity of the shaft.

[0052] The pins engage the shaft with the undercarriage frame (or an undercarriage component integral with the undercarriage frame) to maintain the roller assembly in place and allow the roller body to rotate about the shaft.

[0053] The pins are typically removable to allow the wheel assembly to be removed from the undercarriage car.

[0054] If the temperature transducer is connected to the electronic sensor module by an electrical wire and the housing base intersects the pin, removing the pin will permanently break the connection between the temperature transducer and the electronic sensor module because the electrical connection will cross the pin. Furthermore, by not having the housing base intersect the pin, positioning of the temperature transducer within the housing base can be accomplished even when the roller assembly is not yet attached to the undercarriage frame.

[0055] Preferably, the wheel body includes an opening that fluidly connects the external environment with the annular chamber filled with lubricant, the opening being closed by a plug.

[0056] Further features and advantages of the present invention will become more apparent from the following description of preferred embodiments of the invention, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0057] [Figure 1] FIG. 2 is a schematic side view of the tracked undercarriage. [Figure 2] 1 is a cross-sectional view of a tracked undercarriage roller assembly according to the present invention; [Figure 2A] FIG. 3 is an enlarged detail of a portion of the roller assembly of FIG. 2. [Figure 3]FIG. 3 is a partially exploded perspective view of a detail of the roller assembly of FIG. 2. [Figure 4] FIG. 3 is a schematic diagram of some components of the roller assembly of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0058] Figure 1 is a schematic side view showing some components of a tracked undercarriage. Tracked undercarriage 10 includes two track assemblies 11, only one of which is visible in Figure 1. Each track assembly 11 includes a chain 12 with multiple links 13 interconnected therebetween by pins and bushings (not shown), a return wheel 14, partially hidden in the figure by a crankcase 15, and a drive wheel 16. A plurality of track roller assemblies 17 are disposed between return wheel 14 and drive wheel 16, specifically, one or more upper and lower track roller assemblies disposed in contact with links 13 and adapted to guide chain 12 during its movement.

[0059] The lower roller assemblies 17 are located on the lower portion of the track assembly 11 and are configured to transfer loads between the track and the undercarriage frame (not shown). The upper roller assemblies 17 are configured to guide the chain between the drive wheels 16 and the return wheels 14 and are typically present in smaller numbers than the lower roller assemblies. The number of lower roller assemblies 17 varies depending on the type of machine and its weight.

[0060] According to the present disclosure, at least the lower roller assembly or upper roller assembly 17 includes a sensor device for monitoring temperature.

[0061] 2 is a cross-sectional view of one embodiment of a roller assembly 17. In this embodiment, the roller assembly 17 is a lower roller assembly. The cross-sectional plane is a longitudinal plane that is transverse to the direction of movement of the links 13 of the chain 11 and therefore the track undercarriage, and passes through the axis of rotation X of the roller assembly 17.

[0062] The roller assembly 17 comprises a roller body 18 having a cylindrical through cavity 19 extending from one first axial end 18a to a second axial end 18b of the roller body 18.

[0063] The roller body 18 is bounded by a radially inner surface 20, which typically has a cylindrical shape facing the cylindrical cavity 19, and a radially outer surface 21, the shape of which is determined by the type of track 12 with which the roller assembly 17 must interact.

[0064] The roller body 18 is made of low-alloy steel that has been boron-alloyed and subjected to at least a heat treatment, whereby other elements besides iron and carbon are present, and none of these other elements is present in a content exceeding 5%.

[0065] The roller assembly 17 further comprises a shaft 22 inserted into the cylindrical cavity 19 of the roller body 18. The shaft has a substantially cylindrical shape and extends between a first axial end 22a and a second axial end 22b, and has a radially outer surface 23 opposite the radially inner surface 20 of the roller body 18.

[0066] The shaft 22 is preferably made of a low alloy steel that is boron alloyed and has been subjected to at least a heat treatment.

[0067] The shaft 22 extends axially for a greater distance than the axial extension of the roller body 18. In other words, the axial distance between the first axial end 22a and the second axial end 22b of the shaft 22 is greater than the distance measured along the axial direction between the first axial end 18a and the second axial end 18b of the roller body 18.

[0068] The shaft 22 extends axially beyond the first axial end 18a and the second axial end 18b of the focusing wheel body 18. In particular, as shown in Figure 2, the length by which the shaft extends axially beyond the first axial end 18a of the focusing wheel body 18 is substantially equal to the length by which the shaft 22 extends axially beyond the second axial end 18b of the focusing wheel body 18.

[0069] The shaft portion 22 extending axially outward from the first axial end 18a of the roller body 18 is integrated with the lower running body frame portion or a lower running body component integrated with the lower running body frame portion.

[0070] For this purpose, as shown in Figure 2, a support 24 is provided which is integrated with the undercarriage frame or with an undercarriage component which is integrated with the undercarriage frame and which has an internal through-cavity 25 into which the shaft portion 22 extending axially outward from the first axial end 18a of the roller body 18 is inserted.

[0071] To integrate the shaft 22 with the support 24, the shaft 22 is provided with a radial cavity 26 that radially intersects the shaft 22. Two radially opposing through holes are formed on the support 24, and the two through holes can be aligned with each other and with the radial cavity 26 of the shaft 22. A pin 27 is inserted into the radial cavity 26 so as to cross the radial cavity 26 and block the two through holes of the support 24. This prevents the shaft 22 from moving axially relative to the support 24 and from rotating about the rotation axis X.

[0072] Similarly, the shaft portion 22 extending axially outward from the second axial end 18b of the roller body 18 is integrated with the lower running body frame portion or a lower running body component integrated with the lower running body frame portion.

[0073] For this purpose, as shown in FIG. 2, a further support 28 is provided which is integrated into the undercarriage frame or into an undercarriage component which is integrated into the undercarriage frame, and which has an internal through-cavity 29 into which the shaft portion 22 extending axially outward from the second axial end 18b of the roller body 18 is inserted.

[0074] To integrate the shaft 22 with the further support 28, the shaft 22 is provided with a radial cavity 30 that radially intersects the shaft 22. Two radially opposing through-holes are formed on the further support 28, which can be aligned with each other and with the radial cavity 30 of the shaft 22. A further pin 31 is inserted into the radial cavity 30 so that the pin 31 crosses the radial cavity 30 and blocks the two through-holes of the support 28. This prevents the shaft 22 from moving axially relative to the further support 28 and from rotating about the rotation axis X.

[0075] The roller body 18 is rotatable relative to the shaft 22 about a rotation axis X. As shown in Figure 2, a bushing 32 is provided radially between the roller body 18 and the shaft 22 to reduce friction between the roller body 18 and the shaft 22.

[0076] The bushing 32 is made of brass, bronze, copper, or other metallic material that is preferably more ductile than the material used to make the shaft 22 and the roller body 18. The bushing material 32 also has good thermal conductivity, for example, greater than 15 W / m°C.

[0077] In a preferred embodiment of the present invention, bushing 32 is rotationally integral with wheel body 18 and therefore rotates relative to shaft 22 .

[0078] 2, the bushing 32 extends over the entire axial extent of the roller body 18 between a first axial end 32a and a second axial end 32b. The bushing 32 has a radially inner surface 33 that directly faces the shaft 22. An annular chamber 34 is defined between the radially inner surface 33 of the bushing 32 and the radially outer surface 22c of the shaft 22, and is filled with a lubricant, such as oil or grease, to further reduce friction between the shaft 22 and the bushing 32.

[0079] The annular shaft 34 is in fluid communication with a reservoir 35 found in the roller body 18 through one or more radial passage holes 33a provided in the bushing 33. The reservoir 35 is also in fluid communication with a channel (not shown) found in the roller body 18, which has an annular shape and extends radially between the reservoir 35 and the radially outer surface 21 of the roller body 18. The channel has the purpose of making it possible to introduce lubricant into the reservoir 35 and thus into the annular chamber 34. The channel is closed by a leak-tight plug (not shown).

[0080] At the first annular end 18a and the second annular end 18b of the roller body 18, respective hydraulic sealing rings 36 are arranged to prevent leakage of lubricant between the bushing 33 and the supports 24, 28 of the shaft 22. At the two portions of the shaft 22 extending axially outward from the first axial end 18a and the second axial end 18b of the roller body 18, respective hydraulic sealing gaskets are further provided between the shaft 22 and the supports 24, 28 to prevent leakage of lubricant between the shaft 22 and the supports 24, 28.

[0081] Inside the shaft 22, a receiving seat 37 is obtained which is defined by a blind cavity 38 in the shaft 22. The blind cavity 38 has axial symmetry with respect to an axis of symmetry parallel to the axis of rotation X.

[0082] The receiving base portion 37 extends axially deep within the shaft from an inlet portion 39 to a measuring portion 40. The inlet portion 39 is located at an axial end surface 22d of the shaft 22, which is located at the first axial end 22a of the shaft 22. The inlet portion 39 is open to define an opening of a cavity 38.

[0083] The measuring portion 40 is disposed deep inside the shaft 22, and in particular, is disposed axially at the position of the bushing 32. As shown in Fig. 2, the measuring portion 40 is disposed axially between the first axial end 32a and the second axial end 32b of the bushing 32.

[0084] The inlet portion 39 and the measurement portion 40 are axially aligned such that the blind cavity 38 is parallel to the axis of rotation X.

[0085] The measuring portion 40 is disposed at a fixed radial distance from the radially outer surface 23 of the shaft 22. The measuring portion 40 does not contact the radially outer surface 23 of the shaft 22 and does not open onto the radially outer surface 23.

[0086] As best shown in FIG. 2A, the measuring portion 40 is positioned at a radial distance RD (Radial Distance) from the bushing 32 between 8 mm and 50 mm.

[0087] The radial distance RD is measured between the inner cavity 38 radially closest to the bushing 32 and the radially inner surface 33 of the bushing 32, as shown in FIG. 2A.

[0088] A temperature transducer 41 is inserted into the measuring portion 40 of the receiving base 37 .

[0089] The temperature transducer 41 is configured to generate an electrical signal representative of the measured temperature. For example, the temperature transducer 41 is a thermal probe, preferably an NTC (Negative Temperature Coefficient) probe, which has a negative temperature coefficient that decreases its electrical resistance as the temperature increases. Preferably, the temperature transducer 41 is adapted to measure temperatures up to approximately 200°C.

[0090] In the inlet section 39 there is arranged an electronic sensor module 42 configured to generate a wireless mode measurement signal containing data representative of the temperature measured by the temperature transducer 41 .

[0091] As best seen in FIG. 2A, the inlet portion 39 extends radially longer than the measurement portion 40 to accommodate the electronic sensor mode 42 .

[0092] In a preferred embodiment of the present invention, the radial extension of inlet portion 39 is approximately twice the radial extension of measurement portion 40 .

[0093] The axial extension of the inlet portion 39 is selected to fit and substantially accommodate the electronic sensor module 42 .

[0094] The electronic sensor module 42 and the temperature transducer 41 are electrically connected by an electrical wire 43 therebetween.

[0095] As shown schematically in FIG. 4, the electronic sensor module 42 includes a connector 44 for connecting with an electrical wire 43 .

[0096] Sensor electronics module 42 includes circuitry 45 operatively connected to electrical wires 43 for capturing signals from temperature transducer 41 and producing output electrical signals representative of the measured temperature.

[0097] The circuitry 45 of the electronic sensor module 42 includes circuitry for managing the signal from the temperature transducer 41, which may include conditioning circuitry for the analog signal from the temperature transducer 41 and possible amplifiers for converting the input signal to a voltage or current, analog, or digital output signal. Typically, the electrical signal output from the circuitry is a digital electrical signal. To this end, the circuitry 45 may include an analog-to-digital (A / D) signal converter. The electrical signal output from the first circuitry includes data representing the instantaneous temperature measured by the temperature transducer 41 in the shaft 22.

[0098] The electronic sensor module 42 comprises an electronic processor 46, in particular a microprocessor, associated with a memory, which receives and stores the measurement signals coming from the circuit components 45 and later transmits them to a wireless transmitter 47 for transmitting them in wireless mode via an antenna 48.

[0099] The wireless transmitter 47 is configured to generate a radio frequency signal. In particular, the wireless transmitter 47 is a radio frequency transmitter configured to receive a measurement signal including data representative of the temperature from the processor 46 and to generate a respective radio frequency (RF) signal including the data representative of the temperature. The wireless transmitter 47 is operatively connected to the antenna 45 for transmitting the RF signal.

[0100] The electronic sensor module 42 further comprises a power supply 49 , such as a button cell battery, for supplying the circuitry 45 and the microprocessor 46 .

[0101] Preferably, as shown in FIG. 2A, the electronic sensor module 42 is inserted into a container 50 located inside the inlet portion 39 of the receiving base 37. The container 50 ensures better protection for the circuit components and electronics contained in the electronic sensor module 42. In a preferred embodiment, the container 50 is a vibration-absorbing synthetic rubber case with a front opening 51 facing the axially outer surface 22d of the shaft 22 (FIG. 3). The container 50 is filled with epoxy resin to further damp external stresses and make the electronic sensor module 42 leak-tight.

[0102] The container 50 is closed by a closure 52, which fits into the inlet opening 39 of the receiving base 37 so as to preferably tightly close the front opening 51 and seal the blind cavity 38. The closure 52 is made of a material that is transparent to the passage of radio signals transmitted via the antenna 48. The closure 52 is axially outside the electronic sensor module 42. The closure 52 is axially outside the container 50.

[0103] The inlet portion 39 of the receiving seat 37 includes an annular groove 53, which is formed in the blind cavity 38 and is located on the surface 22d of the axial end 22a of the shaft 22. The annular groove 53 is configured to receive and retain a retaining ring 54. The retaining ring 54 is preferably a resilient ring made of steel, the resilience being provided by an open periphery of the ring. The retaining ring 54 is axially outward of the electronic sensor module 42. The retaining ring 54 is axially outward of the closure plug 52. The retaining ring 54 is axially outward of the container 50.

[0104] Starting from the axially inner position and moving toward the axially inner position, a retaining ring 54 is provided to fit into annular groove 53 (located at the same axial position as retaining ring 54), followed by a stopcock 52, and then an electronic sensor module 42 housed within container 50.

[0105] The receiving seat 39 extends radially to receive the retaining ring 54 , the closure plug 52 , and the container 50 .

[0106] 2 and 2A, receiving seat 37 does not block or intersect radial cavity 26, which extends radially across shaft 22 and receives pin 27. Non-through cavity 38 is not in fluid communication with and does not intersect radial cavity 26, which extends radially across shaft 22 and receives pin 27.

[0107] Those skilled in the art will recognize that various features of the above-described embodiments can be combined to provide further embodiments, all of which fall within the scope of the present invention as defined by the claims that follow.

Claims

1. a wheel body (18) having a through cavity (19) bounded by a radially inner surface (20); a shaft (22) inserted into the through cavity (19) of the roller body (18); a bushing (32) extending from a first axial end (32a) to a second axial end (32b) and radially interposed between the roller body (18) and the shaft (22); an annular chamber (34) radially interposed between the shaft (22) and the bushing (32), the annular chamber (34) being at least partially filled with lubricant; a receiving base (37) provided in the shaft (22) with an inlet portion (39) located at an axial end face (22d) of the shaft (22) and a measuring portion (40) located axially inside the shaft (22) between the first axial end (32a) and the second axial end (32b) of the bushing (32), the inlet portion (39) and the measuring portion (40) being aligned with each other along the axial direction; a temperature transducer (41) located in the measuring portion (40) inside the receiving base portion (37); Equipped with A tracked undercarriage wheel assembly (17) wherein the measuring portion (40) is located at a radial distance from the bushing (32) between 8 mm and 50 mm.

2. 2. The roller assembly (17) according to claim 1, wherein the receiving base portion (37) is a blind cavity (38) symmetrical about an axis of symmetry parallel to the axial direction.

3. 3. The roller assembly (17) according to claim 1 or 2, further comprising an electronic sensor module (42) configured to output in wireless mode a measurement signal containing data representative of a temperature, said electronic sensor module (42) being installed in the inlet portion (39) of the receiving base (37).

4. 4. The roller assembly (17) of claim 3, wherein the inlet portion (39) includes an annular groove (53) engaged by a retaining ring (54), the annular groove (53) being axially outward of the electronic sensor module (42) such that the retaining ring (54) maintains the electronic sensor module (42) axially within the inlet portion (39).

5. 5. The roller assembly (17) according to claim 4, further comprising a stop plug (52) for the inlet portion (39) of the receiving base (37), the stop plug (52) being axially interposed between the retaining ring (54) and the electronic sensor module (42).

6. 6. A roller assembly (17) according to any one of claims 1 to 5, wherein the inlet portion (39) extends radially further than the measuring portion (40) extends radially.

7. 6. The roller assembly (17) according to any one of claims 3 to 5, wherein the temperature transducer (41) is connected to the electronic sensor module (42) via an electrical wire (43).

8. 8. The roller assembly (17) according to claim 1, further comprising a pin (27, 31) inserted into a radial cavity (26, 30) of the shaft (22) to integrate the shaft (22) with an undercarriage chassis, and the receiving base portion (37) does not intersect with the radial cavity (26, 30) of the shaft (22).

9. 9. A roller assembly (17) according to any one of claims 1 to 8, wherein the temperature transducer (41) is a thermistor with a resistance that decreases as the temperature increases.

10. 10. A roller assembly (17) according to any one of claims 1 to 9, wherein the roller body (18) has an opening that fluidly connects the external environment to the annular chamber (34) filled with lubricant, and the opening is closed by a plug.

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