Differentialsperre

Abstract

Differential lock, in particular for an automatic shift control system, locks (2, 8), in particular for an axle differential or a crown intermediate axle differential, which contain axially interlocking locking elements (2, 8) which have interlocking teeth, wherein the toothing consists on the one hand of spur teeth which are arranged on the lock (2, 8) and on the other hand of spur teeth which are arranged on the central gear (3) or on the driver (9) of the crown gear.

Description

Technical area The invention relates to a differential lock, in particular for an automatic switching control system for locks, especially for an axle differential or crown inter-axle differential lock, which includes axially interlocking locking elements with interlocking teeth. State of the art An example from the state of the art is the design of the differential lock of the Jeep Wrangler, in which, however, a differential with bevel gears is used and the switching of the lock is carried out by an electromagnet. Another application example is described in the text by Jasný M. entitled “Dog Clutch Without Circular Backlash”, ČVUT Praha. Here, the spur gear clutch is not part of the differential lock, but serves to engage different gears in the transmission. Document US 3915032 discloses an intermediate axle differential with bevel gears, the differential lock of which is designed as a toothed coupling between the input shaft and the drive element connected to the output shaft. The solution described in US patent 3915032 is applied to a bevel gear intermediate axle differential on whose drive pin the spur gear of the tandem axle drive is mounted. This is a completely different solution than the one presented in the present invention. Document GB808543 discloses an axle differential with a ring gear, the differential lock of which is designed as a toothed coupling between the half-shaft and the differential cage. The solution described in document GB808543 is applied to a bevel gear differential in which a planetary gear set is integrated, enabling reduced-load operation. The planetary gear set and the differential itself can be locked independently. The sketch and text do not indicate that a spur gear is used in the shifting mechanism. This is a completely different solution from the presented invention. Document US2023088870 also discloses an axial differential with bevel gears, the differential lock of which is designed as a toothed coupling. This document specifies control by an electromagnet and the use of a cam mechanism, which is not visible at all in the accompanying illustration. Figure 5 of this document shows that a disc spring is inserted between the locking element and the bevel gear, which serves to disengage the differential lock. This is a completely different differential design than in the present invention. Document GB1017911 also discloses an axial differential whose differential lock is designed as a toothed coupling between the half-shafts. The solution described in document GB1017911 is applied to a bevel gear differential. In the description of the invention, the toothing is referred to as a "dog clutch," but this is actually a toothing on the cylindrical surface of the sliding element, see items 9 and 11 in the satellite. The idea of ​​using an internal locking element with a coil spring to disengage the differential shaft is interesting. This is a completely different solution from the presented invention. The patents mentioned above deal with bevel differentials, but the present invention deals with a differential with spur gears. In the known TATRA axle differential (see Fig. 1), the central gear 3, which is slidably mounted on the tubular shaft 5, is provided on the side adjacent to the locking mechanism 2 with a reduced outer gear diameter and a second engagement length L2. The locking mechanism 2 is provided with internal teeth with a first engagement length L1, the spur gearing of both elements being dimensioned with respect to its shape, size, and module for mutual engagement to reliably transmit the input torque Mk i, i.e., to close the axle differential. This solution corresponds to the current state of the art for the locking mechanism 2 and the central gear 3 and consists of utilizing the shape of the flank and root of the spur gearing of the internal and external teeth, respectively. In an axle differential with spur gears, the input torque Mk i is thus transmitted via the first connecting shaft 4 to the cage 1 of the axle differential.From there, the input torque Mk i is transmitted via satellites through a groove connection to the first output torque Mk o1 on the pinion 6 of the axle and to the second output torque Mk o2 via the central gear on the tubular shaft 5. The axle differential is closed by sliding the locking mechanism 2 in the internal teeth of the cage 1, so that the internal teeth with engagement length L1 engage in the gaps of the external teeth of the central gear 3 with the second engagement length L2. The closed locking mechanism 2 of this axle differential is then shown in detail in Fig. 3. In the advantageous embodiment, the engagement lengths L1 and L2 are identical. In the known TATRA inter-axle crown differential (see Fig. 7), a locking device 8 is slidably arranged on the cage 7 of the inter-axle crown differential. This locking device is provided on its circumference, next to the drive 9 of the crown gear, with external teeth featuring spur teeth with a fifth engagement length L5. The inner diameter of the drive 9 is provided with internal teeth featuring a sixth engagement length L6. The spur teeth of both elements are dimensioned with respect to their shape, size, and module for mutual engagement such that the input torque Mk i is reliably transmitted, i.e., the inter-axle differential is locked. This solution corresponds to the prior art for the locking device 8 and drive 9 and consists of utilizing the shape of the flank and root of the spur teeth on the inside and outside, respectively.In this intermediate differential, the input torque Mk i is transmitted via a second connecting shaft 10 to the first rear axle and then to the cage 7 of the intermediate differential. From there, the input torque Mk i is transmitted via the crown gear to the first output torque Mk o1 on the cage 12 of the axle differential for the rear axle and to the second output torque Mk o2 on the third connecting shaft 11 of the reduction gear. The intermediate differential is closed by sliding the locking mechanism 8 of the intermediate differential on the outer teeth of the cage 7 of the intermediate differential, so that the outer spur teeth on the locking mechanism 8 of the intermediate differential, with a fifth engagement length L5, engage in the gaps of the inner spur teeth of the drive pin 9 of the crown gear, with a sixth engagement length L6.This solution represents the current state of the art for the locking element 8 and the drive element 9 and consists of utilizing the shape of the flank or the base of the inner or outer face teeth. The closed locking element 8 of the inter-axis crown differential is then shown in detail in Fig. 9. The engagement lengths L5 and L6 are identical in the advantageous embodiment. The essence of the invention The object of the invention is to eliminate the shortcomings of the prior art and, in particular, to increase the strength of the interlocking elements of the differential locks for the use of an automatic control system for the differential lock. The aforementioned problem is solved by a differential lock, particularly for an automatic transmission control system, and especially for an axle differential or crown-type inter-axle differential lock, which contains axially interlocking locking elements having interlocking teeth. According to the invention, the teeth consist on one side of spur teeth arranged on the lock and on the other side of spur teeth arranged on the central gear or the drive pin of the crown gear. The advantageous design consists in the fact that the engagement lengths of the corresponding teeth are identical. The advantage of the new solution lies in the ability to integrate the spur gear locking mechanism into both a spur gear axle differential assembly and an inter-axle differential assembly without requiring modifications to the differential cage. The spur gear design allows for tooth reinforcement, which transmits the torque surge when the lock engages under load. This is particularly beneficial for automatic differential lock control systems, where the locking frequency is significantly higher than with manual control. Current solutions using engagement grooves are unable to transmit this high switching frequency due to the lower strength of the grooves with their low groove module. Explanation of the drawings The invention is explained in more detail below with reference to specific embodiments shown in the drawings. Fig. 1 Longitudinal section through an axial differential with spur gears and detail D1 of the locks and the center gear (prior art), Fig. 2 Center gear and the locks of the axle differential in the open position (prior art), Fig. 3 Center gear and the closed lock of the axle differential (prior art), Fig. 4 Longitudinal section through the axle differential with spur gears in the closed position of the locks 2 of the axle differential and detail D2 of the closed locks and drive pinion (presented invention), Fig. 5 Center gear and the open lock of the axle differential (presented invention), Fig. 6 Center gear and the closed lock of the axle differential (presented invention), Fig.Fig. 7 Longitudinal section through the intermediate axle differential with detail D3 of the closed latches and the drive pinion of the crown gear with spur teeth (prior art), Fig. 8 Crown gear drive pinion and the open axle differential latch (prior art), Fig. 9 Crown gear carrier and the closed latch of the axle differential (prior art), Fig. 10 Longitudinal section through the intermediate axle differential with detail D4 of the open latches and the drive pinion of the crown gear (presented invention), Fig. 11 Crown gear drive pinion and the open latch of the axle differential (presented invention), Fig. 12 Crown gear drive pinion and the closed latch of the axle differential (presented invention). Examples of the implementation of the invention The present invention is based on the prior art, which is illustrated for the axle differential with spur gears in Figs. 1, 2 to 3 and for the inter-axle crown differential in Figs. 7, 8 to 9, whereby reference numerals corresponding to the present invention are used for clarity. In the axle differential (Fig. 4), the central gear 3, which is slidably arranged on the tube shaft 5, is provided on the side adjacent to the lock 2 with a toothing with spur teeth having a fourth engagement length L4, and the side of the lock 2 of the axle differential is provided with a toothing with spur teeth having a third engagement length L3, wherein the spur teeth of both toothings are dimensioned with regard to their shape, size and module for mutual engagement to reliably transmit the input torque Mk i, i.e. to close the axle differential. The solution according to the presented invention for the axle differential therefore consists, on the one hand, in a modification of the locking system of the lock 2 of the axle differential, wherein the lock of the central gear 3 is modified by utilizing the shape of its flank or the heel of the spur gear of the central gear 3 in the manner of a spur gear coupling. In an axial differential with spur gears, the input torque Mk is transmitted via the first connecting shaft 4 to the cage 1 of the axial differential for the front axle. From there, the input torque Mk i is transmitted via satellites through a splined connection to the first output torque Mk o1 at the pinion 6 of the axle and to the second output torque Mk o2 via the central gear 3 to the tubular shaft 5. The axle differential is locked by sliding the locking mechanism 2 in the internal teeth of the cage 1, so that the spur teeth on the locking mechanism 2, with the third engagement length L3, engage in the gaps between the spur teeth of the central gear 3, with the fourth engagement length L4. Figure 4 shows the closed locking mechanism 2 of the axle differential in detail. In the advantageous embodiment, the engagement lengths L3 and L4 are identical. The solution according to the presented invention further consists in a modification of the locking system of the lock 8 of the inter-shaft crown differential, wherein the lock of the driver 9 of the crown gear is also modified in the manner of a spur gear coupling by utilizing the shape of its side or the heel of the spur gearing of the driver 9 of the crown gear. In the inter-axle differential, a locking device 8 is slidably arranged on the cage 7 of the inter-axle differential on the side adjacent to the driver 9 of the crown gear, which is provided with spur teeth with a seventh engagement length L7, and the side of the driver 9 of the crown gear is provided with spur teeth with an eighth engagement length L8, wherein the spur teeth of both gears are designed in their shape, size and module for mutual engagement to reliably transmit the input torque Mk i, i.e. to close the inter-axle crown differential. In the crown-type intermediate differential (Fig. 10), the input torque Mk i is transmitted via a second connecting shaft 10 to the first rear axle and then to the cage 7 of the crown-type intermediate differential. From there, the input torque Mk i is transmitted via the crown gear to the first output torque Mk o1 at the cage 12 of the axle differential for the rear axle and to the second output torque Mk o2 at the third connecting shaft 11 of the reduction gear. The intermediate differential is closed by sliding the locking mechanism 8 of the intermediate differential on the external teeth of the cage 7 of the intermediate differential, so that the spur teeth on the locking mechanism 8 of the intermediate differential, with a seventh engagement length L7, engage in the gaps between the spur teeth of the drive pin 9 of the crown gear, with an eighth engagement length L8. In the advantageous embodiment, the engagement lengths L7 and L8 are also identical.The closed closure 8 of the inter-axis crown differential is then shown in detail in Fig. 12. Reference symbol list 1 Cage (front axle differential) 2 Lock (axle differential) 3 Center gear 4 First connecting shaft 5 Tube shaft 6 Pinion 7 Intermediate differential cage 8 Intermediate differential lock 9 Crown gear carrier 10 Second connecting shaft 11 Third connecting shaft 12 Rear axle differential cage Mk i Input torque Mk o1 First output torque Mk o2 Second output torque L1 First input shaft length L2 Second engagement length L3 Third engagement length L4 Fourth engagement length L5 Fifth engagement length L6 Sixth engagement length L7 Seventh engagement length L8 Eighth engagement length QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature US 3915032

[0004] GB 808543

[0005] US 2023088870

[0006] GB 1017911

[0007]

Claims

Differential lock, in particular for an automatic shift control system, locks (2, 8), in particular of an axle differential or a crown-type intermediate axle differential, which contain axially cooperating elements of the lock (2, 8) which have interlocking teeth, characterized in that the toothing consists on the one hand of spur teeth which are arranged on the lock (2, 8), and on the other hand of spur teeth which are arranged on the central gear (3) or on the driver (9) of the crown gear. Differential lock according to claim 1, characterized in that the engagement lengths (L3, L4; L7, L8) of the corresponding teeth are equal.

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