WO2004057731A1

WO2004057731A1 - Reversing motor with a protection device for the gear mechanism

Info

Publication number: WO2004057731A1
Application number: PCT/EP2003/014237
Authority: WO
Inventors: Bernd Walther
Original assignee: Valeo Wischersysteme Gmbh
Priority date: 2002-12-19
Filing date: 2003-12-15
Publication date: 2004-07-08
Also published as: AU2003290047A1; DE10259396A1

Abstract

A reversing motor (2), especially for driving a windscreen wiper system in a motor vehicle, comprising an armature shaft (10) which is exposed to axial thrust forces (62, 66). The armature shaft (10) is mounted in two rolling bearings (18, 20) whose inner rings (24, 42) are arranged with a sliding seat on the armature shaft (10). A respective elastic element (30,50) is supported on a securing element (32,52) fixed to the armature shaft in an axial direction on the sides of the inner rings (24,42) which respectively face each other or face away from each other, enabling axial thrust forces (62, 66) to be transferred to the inner rings (24, 42) and then on to a housing (4,6) of the reversing motor (2) by means of rolling bodies (26, 44) and outer rings (28, 46) which are fixed to the housing. Deformation of the respective elastic element (30, 50) only occurs if the thrust forces (68, 70) are higher than the thrust forces (62, 66) which occur during normal trouble-free operation of the reversing motor (2).

Description

Title: REVERSING MOTOR WITH A PROTECTIVE ARRANGEMENT FOR THE GEARBOX

The invention relates to a reversing motor, in particular for driving a windshield wiper system, in particular a motor vehicle, with an armature shaft exposed to axial thrust forces.

Reversing motors for driving windshield wiper systems of motor vehicles are distinguished by the fact that their direction of rotation can be reversed in accordance with the wiper blades moving back and forth on a windshield or a rear window. This has the advantage that a linkage for driving two wiper arms can be made very small, or that each wiper arm can be operated independently by coupling to its own drive motor, so that no transmission linkage is required at all.

However, the rods that are conventional in conventional drives of wiper arms have the advantage that blocking forces that occur during operation of the wiper system can be absorbed by elastic deformation of the rods. Such a deformation, however, only occurs when the forces that occur during normal operation of the windshield wiper system are exceeded, for example in the case of a sudden load which occurs, for example, when large amounts of snow are removed from a windshield. In conventional windshield wiper systems, the sudden load on the wiper arms is also transmitted via the drive rod to those which are usually provided with teeth Gear means which are provided between the drive rod and the drive motor. Nevertheless, loads acting suddenly on the wiper arms can at least partially be absorbed by the elastic deformation of the drive linkage. Thus, voltage peaks can be reduced, which protects the gear means.

Since there is only a relatively small and light linkage in windshield wiper systems with a reversing motor or if there is no linkage at all when using two reversing motors, the abrupt loads of the wiper arms described above act directly on the gear means arranged between a wiper arm and a reversing motor.

Proceeding from this, it is an object of the invention to provide an arrangement for a reversing motor with which protection of the windshield wiper system, in particular of the gear means, against mechanical overloading, which can occur in particular when the wiper arms are suddenly loaded.

The invention is achieved on the one hand by a generic reversing motor, the armature shaft being mounted in at least one roller bearing, the inner ring of which is arranged with a sliding seat on the armature shaft, wherein in the axial direction on both sides of the inner ring an elastic element supported on an anchor shaft-fixed securing element is supported Element are arranged via the axial thrust forces on the inner ring and from there via a roller body and a housing-fixed outer ring in a housing of the reversing motor, and wherein a deformation of the respective elastic element only occurs at shear forces that are higher than the shear forces that in undisturbed normal operation of the reversing motor occur.

The proposed arrangement provides simple and effective protection against sudden loads on the Windshield wiper system created. The armature shaft is mounted in at least one roller bearing, the armature shaft being displaceable with a sliding seat in the inner ring of the roller bearing. An elastic element is located on both sides of the inner ring as seen in the axial direction. The elastic elements are each supported on securing elements fixed to the anchor shaft.

In normal operation, the axial forces that occur when the wiper arms are driven are conducted from the armature shaft via a securing element to the elastic element and from there to the inner ring of the roller bearing and via the roller body into the outer ring fixed to the housing and into the housing of the reversing motor. Here, the elastic elements are not deformed. A transmission of axial forces into the housing of the reversing motor is possible through the arrangement of securing elements fixed to the anchor shaft and elastic elements on both sides of the inner ring, both with axial thrust forces in a first direction and in the opposite direction to this. In normal operation, the axial forces can therefore be derived in both directions without deformation of the elastic elements in the housing of the reversing motor.

If higher loads occur than usual in normal operation of the windshield wiper system, for example when the wiper arms are suddenly loaded due to large amounts of snow, the axial thrust that occurs is transmitted from the armature shaft to an anchor shaft-fixed securing element to an elastic element. This can now, by deformation, dissipate at least part of the energy resulting from the sudden loading of the wiper arms before the remaining forces are transmitted into the housing of the reversing motor via the inner ring, the roller body and the outer ring.

The deformation of the respective elastic element only with shear forces that are higher than the shear forces that occur in the undisturbed normal operation of the reversing motor the advantage that the armature shaft can be mounted largely without play. It can thus be avoided that the wiper arm or the wiper arms are freely movable around a small angular range in the region of their reversal positions. This is undesirable since the wiper arms can then be moved in their rest position in a small angular range despite the drive being switched off and, moreover, a jerky movement of the wiper arms occurs in the region of the reverse positions when the wiper system is in operation.

The invention is also achieved by a reversing motor of the type mentioned at the outset, the armature shaft being mounted in two roller bearings, the inner rings of which are arranged with a sliding seat on the armature shaft, in the axial direction on the sides of the inner rings which face or face away from one another an elastic element supporting itself on an anchor shaft-fixed securing element is arranged, by means of which axial thrust forces can be transferred to the inner rings and from there via roller bodies and fixed outer rings into a housing of the reversing motor, and wherein a deformation of the respective elastic element only occurs when the thrust forces are higher are the shear forces that occur in the undisturbed normal operation of the reversing motor.

This arrangement differs from the arrangement described above in that two roller bearings are now used instead of one roller bearing. The inner rings of the roller bearings are also each slidably arranged on the armature shaft. In this arrangement with two roller bearings, too, two elastic elements are used, each of which rests on a securing element fixed to the anchor shaft. In each case an elastic element interacts with an inner ring of a roller bearing.

Each of the elastic elements interacts with one of the anchor elements fixed to the anchor shaft. The Securing elements and the elastic elements can be arranged between the roller bearings, so that the elastic elements are each arranged adjacent to the mutually facing sides of the inner rings; however, the securing elements and the elastic elements can also be arranged outside the two roller bearings, so that the elastic elements are arranged adjacent to the sides of the inner rings facing away from one another.

The axial thrust forces can be transmitted in a first axial direction via a first securing element fixed to the anchor shaft and a first elastic element to the inner ring of a first roller bearing and from there via the rolling element and the outer ring into the housing of the reversing motor. In a direction opposite to the first axial direction, the axial thrust forces are transmitted to the inner ring of the second roller bearing via the second anchor shaft-fixed securing element and the second elastic element and from there via the roller body and the outer ring into the housing of the reversing motor.

Even with the use of two roller bearings, the arrangement described above allows the armature shaft to be supported without play, so that in this case too, the wiper arms driven by gear means are supported without play.

Advantageously, the thrust forces which cause the elastic elements to deform are smaller than the thrust forces which would lead to the destruction of the toothing of a gear adjoining the armature shaft. In this way, increased thrust forces that do not occur in normal operation can be reduced without destroying the toothing of a gear arranged between the reversing motor and the wiper arm. The armature shaft is advantageously displaceable in both axial directions in the inner ring or in the inner rings. However, the armature shaft is only displaced by the amount by which the elastic elements are deformed or shortened when the wiper arms are suddenly loaded. Due to the displaceability of the armature shaft in the inner ring or in the inner rings, the armature shaft can be produced simply and inexpensively, since neither precisely tolerated shoulders have to be provided for contact with the inner ring or the inner rings, nor is the surface of the armature shaft in the contact area of the inner ring complex, for example by Tough, needs to be treated.

In an embodiment of the invention, the elastic elements have damping properties. This prevents the deformations that occur in the case of sudden loads from spring-like deflection in the direction opposite to the direction of introduction. Unwanted vibrations are also avoided in the system. By choosing a suitable material, for example an elastomer, the sudden load can be converted into deformation energy, that is to say into thermal energy.

In a particularly advantageous manner, the elastic elements are identical with regard to their spring and / or damping properties. This means that when a roller bearing is used, axial thrust forces can be absorbed in both directions from an identical load threshold by one elastic element each. When using two roller bearings, the use of elastic elements with identical spring and / or damping properties has the advantage that the inner rings of the roller bearings are evenly preloaded against each other.

It is particularly advantageous that the elastic elements have identical spring characteristics and are mounted under the same pretension. Thus, increased thrust can occur in both axial directions are degraded in the same way. In addition, the bearing of the reversing motor is evenly loaded if there are no increased thrust forces, that is to say in the rest position and in normal operation.

Furthermore, it is advantageous that the elastic elements have spring and / or damping properties, which enable a reduction of shear forces that occur in particular when the windshield wiper system is blocked for a short time. Axial shear forces or impact energy are only reduced when the axial shear forces exceed a limit value. By prestressing the elastic element, for example, it can be achieved that it only deforms when forces occur that exceed the forces occurring in the normal, undisturbed operation of the reversing motor. In particular if the windshield wiper system is blocked for a short time, for example due to mechanical effects from the surroundings of the motor vehicle, the forces which occur can be at least partially reduced before the remaining forces are introduced into the housing of the reversing motor via the roller bearing or bearings.

According to one embodiment of the invention, the elastic elements are coupled to sensors which detect the deformation of the elastic elements and are connected to a control of the reversing motor. The sensors can be designed, for example, as pressure sensors and, when a limit pressure is exceeded, send a signal to the controller of the reversing motor, which then automatically switches off the reversing motor. In this way, simple overload protection can be implemented.

In an embodiment of the invention, the anchor element fixed to the anchor shaft is designed as a shaft collar. This creates a particularly reliable connection between the securing element and the armature shaft. It is also possible to shrink the securing element onto the armature shaft or to use a suitable positive connection.

Further advantageous refinements and details of the invention can be found in the following description, in which the invention is described and explained in more detail with reference to the exemplary embodiments shown in the drawing.

Show it:

Figure 1 is a sectional side view of a

Reversing motor when using two roller bearings; and

Figure 2 shows a detail of a side view of a

Reversing motor when using a roller bearing.

In Figure 1, a reversing motor is generally designated with the reference number 2. The reversing motor 2 has a motor housing 4 and a gear housing 6 which is fixedly connected to the motor housing 4. The gear housing 6 is provided with a gearbox 8. (For reasons of clarity, other components of the reversing motor 2, such as armature angle, stator, commutator and brush arrangement, are not shown.)

An armature shaft 10 is mounted in the motor housing 4 or in the gear housing 6, the armature shaft 10 being designed as a worm shaft 12 in a section adjacent to the gear cup 8 of the gear housing 6. The worm shaft 12 meshes with a worm wheel 14 which is non-rotatably connected to an output shaft 16. A wiper arm, not shown, of a windshield wiper system is fastened to the output shaft 16.

The armature shaft is with the help of roller bearings 18 and 20 and with the help of a sliding bearing 22 at a total of three locations stored. The roller bearing 18 shown on the left has an inner ring 24 which is arranged on the armature shaft 10 with a sliding seat. The roller bearing 18 also has roller bodies 26 in the form of balls and an outer ring 28.

An elastic element 30 is provided adjacent to the roller bearing 18 on the side of the inner ring 24 facing the roller bearing 20. In the embodiment shown, the elastic element 30 is designed as a ring and lies flat against the inner ring 24 of the roller bearing 18. The elastic element 30 has a curved surface on the side facing away from the inner ring 24, which cooperates in a partial section 31 with a shaft collar 32 provided on the armature shaft 10.

The roller bearing 18 is arranged adjacent to a stop 34. This is held in a housing extension 36 of the motor housing 4 and fastened there via fixing elements 38 to the motor housing 4 or to the housing extension 36. The stop 34 has on the side facing the roller bearing 18 an annular section 40 against which the outer ring 28 of the roller bearing 18 abuts.

The roller bearing 20 has an inner ring 42, rolling elements 44 in the form of balls and an outer ring 46. The outer ring 46 bears against a stop 48 in the gear housing 6.

An elastic element 50 is provided on the side of the inner ring 42 facing the roller bearing 18. The elastic element 50 is identical to the elastic element 30. With respect to the roller bearing 18, the elastic elements 30 and 50 are arranged in mirror symmetry. The elastic element 50 is flat on the side facing the inner ring 42 and has a curved surface on the side facing away from the inner ring 42, which in one Section 51 abuts a shaft collar 52 provided on the armature shaft 10.

The armature shaft 10 is also mounted in a slide bearing 22 which receives a free shaft end 54 of the armature shaft 10. For this purpose, a sleeve 56 is provided, which is held in the gear housing 6 via a holding element 58.

When the reversing motor 2 is operated and a wiper arm (not shown) is driven according to the direction of rotation designated 60, an axial force 62 acts on the armature shaft 10. The axial force is transmitted through the shaft collar 52 to the elastic element 50 and further to the inner ring 42 of the roller bearing 20 the rolling elements 44 and the outer ring 46 and the stop 48, the axial force 62 is finally introduced into the gear housing 6.

When the wiper arm (not shown) moves in the direction of rotation designated 64, an axial force labeled direction 66 acts on the armature shaft 10. This axial force 66 is introduced via the shaft collar 32 and the elastic element 30 into the inner ring 24 of the roller bearing 18. From there, the axial force 66 is introduced via the rolling elements 26 into the outer ring 28 and via the stop 34 into the motor housing 4.

In normal operation, the elastic elements 30 and 50 are not deformed. However, if, for example when the wiper arm moves in the direction of rotation indicated by 60, the wiper arm is blocked, for example when the wiper arm collides with larger amounts of snow, a pulse denoted by direction 68 is introduced into the worm wheel 14 via the output shaft 16. By contacting the toothing of the worm wheel 14 with the worm shaft 12, the pulse is transmitted to the armature shaft 10 and acts there in the direction denoted by 62. Thus, the shaft collar 52 suddenly strikes the elastic element 50, which is now partially deformed and thus reduces part of the pulse energy.

The forces required to deform the elastic elements 30 and 50 are smaller than the forces which would destroy the toothing of the worm shaft 12 and the worm wheel 14. Thus, destruction of the worm shaft 12 and the worm wheel is prevented by deforming the elastic members 30 and 50. The remaining energy portion of the above Pulse energy can be introduced into the transmission housing 6 via the inner ring 42 and transmission via the roller body 44, the outer ring 46 and the stop 48.

If there is a blockage of the wiper arm during movement in the direction of rotation denoted by 64, a pulse denoted by direction 70 is transmitted from the wiper arm (not shown) via the output shaft 16 to the worm wheel 12 and thus to the worm shaft and the armature shaft 10. The impulse then acts in the direction denoted by 66 and can be reduced via the shaft collar 32 and the deformation of the elastic element 30. The remaining energy can be introduced into the motor housing 4 via the inner ring 24, the roller bodies 26 and the outer ring 28 and via the stop 34, so that destruction of the toothing of the worm shaft 12 and the worm wheel 14 is avoided.

FIG. 2 shows a second embodiment of a section of a reversing motor, in which only one roller bearing is used. The bearing shown in FIG. 2 can be used, for example, in the reversing motor 2 shown in FIG. 1 at the height of the roller bearing 20 shown there. (Of course, additional bearings, preferably plain bearings, can also be provided in the arrangement according to FIG. 2.) The reversing motor according to FIG. 2 has a motor housing 104, which is shown in sections, and an armature shaft 110, shown partially broken off. The armature shaft 110 is mounted in the motor housing 104 via a roller bearing. The roller bearing has an inner ring 124, roller bodies 126 designed as balls and an outer ring 128. When viewed in the axial direction, elastic elements 130 and 150 are arranged on both sides of the inner ring 124. They are flat on the side facing the inner ring 124. On their respective backsides they have a curved surface, which in sections 131 and 151 rest against rings 132 and 152 fixed to the anchor shaft.

The outer ring 128 of the roller bearing is fixed between a stop 134 provided on the motor housing 104 and a stop 148 integrated in the motor housing 104. The stop 134 is connected to the motor housing 104 via connecting elements 172 (shown only schematically here).

Axial forces that occur during normal operation of the windshield wiper system can be introduced via the rings 132 and 152 fixed to the anchor shaft and the elastic elements 130 and 150 onto the inner ring 124 and via the roller bodies 126 onto the outer ring 128 and via the stops 134 and 148 into the motor housing 104 , If, for example, an axial force occurs in the direction denoted by 162, the anchor shaft-fixed ring 132 presses on the elastic element 130, which in turn acts on the inner ring 124. With axial forces in the direction denoted by 166, the anchor shaft-fixed ring 152 presses on the elastic element 150.

If the forces occurring in normal operation are exceeded, the elastic elements 130 and 150 are deformed. In order to reduce an impulse force that acts in the direction designated 162, the elastic element 130 deforms; to reduce an impulse force, which acts in the direction designated 166, the elastic deforms Element 150. This prevents the teeth of worm shaft 12 and worm wheel 14 from being destroyed.

Claims

claims

1. reversing motor (2), in particular for driving a windshield wiper system, in particular a motor vehicle, with an armature shaft (110) exposed to axial thrust forces (162, 166),

- The armature shaft (110) is mounted in at least one roller bearing, the inner ring (124) of which is arranged with a sliding seat on the armature shaft (110),

- Wherein in the axial direction on both sides of the inner ring each on an anchor shaft-fixed securing element (132, 152) supporting elastic element (130, 150) are arranged, via the axial thrust forces (162, 166) on the inner ring (124) and from there via roller bodies (126) and a housing-fixed outer ring (128) into a housing (104) of the reversing motor

(2) are transferable, and

- Wherein a deformation of the respective elastic element (130, 150) only occurs with shear forces that are higher than the shear forces (162, 166) that occur in the normal operation of the reversing motor (2).

2. reversing motor (2), in particular for driving a windshield wiper system, in particular a motor vehicle, with an armature shaft (10) exposed to axial thrust forces (62, 66),

- The armature shaft (10) is mounted in two roller bearings (18, 20), the inner rings (24, 42) of which are arranged with a sliding seat on the armature shaft (10),

- Wherein in the axial direction on the mutually facing or the facing sides of the inner rings (24, 42) each have a Anchor shaft-fixed securing element (32, 52) supporting elastic element (30, 50) are arranged, via the axial thrust forces (62, 66) on the inner rings (24, 42) and from there via rolling elements (26, 44) and housing-fixed outer rings (28 , 46) in a housing (4, 6) of the reversing motor (2) can be transferred, and

- Wherein a deformation of the respective elastic element (30, 50) only occurs at thrust forces (68, 70) that are higher than the thrust forces (62, 66) that occur during normal operation of the reversing motor (2).

3. Reversing motor (2) according to claim 1 or 2, characterized in that the thrust forces (68, 70) which cause a deformation of the elastic elements (30, 50, 130, 150) are smaller than the thrust forces which destruction of the toothing of a gear (12, 14) adjoining the armature shaft (10, 110).

4. Reversing motor (2) according to one of the preceding claims, characterized in that the armature shaft

(10, 110) in both axial directions (62, 66, 162, 166) in the inner ring (124) or in the inner rings (24, 42).

5. Reversing motor (2) according to one of the preceding claims, characterized in that the elastic elements (30, 50, 130, 150) have damping properties.

6. reversing motor (2) according to any one of the preceding claims, characterized in that the elastic elements (30, 50, 130, 150) are identical in terms of their spring and / or damping properties.

7. reversing motor (2) according to any one of the preceding claims, characterized in that the elastic Elements (30, 50, 130, 150) have identical spring characteristics and are mounted under the same preload.

8. reversing motor (2) according to any one of the preceding claims, characterized in that the elastic elements (30, 50, 130, 150) have spring and / or damping properties which allow a reduction of shear forces (68, 70), which at short-term blocking, especially of the windscreen wiper system.

9. Reversing motor (2) according to one of the preceding claims, characterized in that the elastic elements (30, 50, 130, 150) are coupled with the deformation of the elastic elements (30, 50, 130, 150) sensors which are coupled with a controller of the reversing motor (2) are connected.

10. Reversing motor (2) according to any one of the preceding claims, characterized in that the anchor shaft-fixed securing element (32, 52) is designed as a shaft collar.