DE102008032819A1 - Combined brake for motor vehicle, has gear converting rotational into translational movements by spindle and nut contacting each other by bodies arranged to move between stops in thread path with spring unit arranged between bodies and stop - Google Patents

Abstract

The brake has a hydraulically operable working brake and an electromechanically operable parking brake that acts on a brake piston (5) by a gear (1). The gear converts a rotational movement into a translational movement by a threaded spindle (2) and a threaded nut (3) that contact each other by roller bodies (4). The bodies are arranged to move between stops in a thread path with a spring unit (10) arranged between the bodies and one stop, where slippage of the bodies is permitted on load-free operation of the gear, and rolling of the bodies is permitted on operation of the gear under load.

Description

The The present invention relates to a combined vehicle brake, a hydraulically actuated service brake and a Electromechanically actuated parking brake device having, wherein in a brake housing, a hydraulic Operating pressure chamber is limited by a brake piston, which is to carry out Served by service braking with hydraulic pressure medium is, so that the brake piston to achieve a braking effect along a piston longitudinal axis (A) is actuated, and wherein the parking brake device on the brake piston means a gear works by the gearbox the rotational movement an electromechanical actuator in a translational movement converts and actuation of the brake piston for implementation effected by parking brake operations and actuated in the Holds position, the gear is a threaded spindle and a threaded nut, which has several between two stops in the thread limited movably arranged Rolling elements are in contact with each other, wherein at least one spring element between the rolling elements and a stop is arranged and at a load-free operation the gear allows slipping of the rolling elements and upon actuation of the transmission, under load, unrolling allows the Wälzkör by. Furthermore The invention relates to a method of assembly.

Such a hydraulic vehicle brake with electrically operated parking brake device is for example from the DE 101 50 803 B4 known. In the known vehicle brake, a transmission is provided, which converts the rotational movement of the electric motor into a longitudinal movement of the brake piston to achieve a locking force according to the operating principle of a threaded nut spindle arrangement. According to one embodiment, this gear unit is designed as a so-called "spindle / ball bearing bushing arrangement", which is also called a ball screw or ball screw These ballscrews have a threaded spindle and a threaded nut, which are in contact with one another via a plurality of rolling elements is always a ball channel provided, as for example in the DE 10 2004 038 951 A1 is disclosed. This ball channel is expensive to manufacture and thus the production of a previously known ball screw is relatively expensive.

Therefore, in the FR 2 337 285 a ball screw without ball return provided. The balls are arranged between two stops and slip or slid on actuation of the ball screw without load while they roll in an operation under load without sliding. In the disclosed embodiment, the stops are formed by pins which are inserted through holes in the threaded nut and protrude into the thread. This form of implementation is relatively complicated, since the hole must be exactly the thread.

It is therefore an object of the present invention, a combined vehicle brake to improve the type mentioned in that the Stops the transmission of electromechanically actuated Parking brake are easy and inexpensive to produce and that the stops are designed such that a easy installation of the transmission can be achieved.

These The object is achieved by a device solved with the features of claim 1. It is intended that the stops formed by two closure elements be larger than the inner diameter of the diameter Threaded nut is and the non-positive due to an elastic deformation are positioned in the threaded nut.

Further advantageous embodiments are the dependent subclaims 2 to 4 removable. So are in a particularly advantageous development of the subject invention, the closure elements by two rings are formed, which are pressed into a groove provided for this purpose or caulked and non-positive after installation are positioned in the threaded nut.

at an alternative embodiment, the closure elements are formed by annular spiral segments whose Circular diameter before mounting larger than the Inner diameter of the nut is and after installation positioned as a result of elastic deformation in the threaded nut are.

Advantageous the closure elements are designed such that the threaded spindle movable without contact with respect to the closure elements is.

• – Einsetzen eines Verschlusselements in die Gewindemutter;
• – Einführen eines zylinderförmigen Platzhalterelements in die Gewindemutter;
• – Einsetzen der Wälzkörper und des mindestens einen Federelements;
• – Einsetzen des zweiten Verschlusselements in die Gewindemutter und
• – Einführen der Gewindespindel in die Gewindemutter und Verdrängen des Platzhalterelements.

The object underlying the invention is also achieved by a method having the features of claim 5. It is provided that the following method steps are carried out:

• - Inserting a closure element in the threaded nut;
• - Inserting a cylindrical Platzhalterelements in the threaded nut;
• - Inserting the rolling elements and the at least one spring element;
• - Inserting the second closure element in the threaded nut and
• - Inserting the threaded spindle into the threaded nut and displacing the placeholder element.

at an advantageous development of the invention Assembly procedure is provided, first that the brake piston facing closure element is inserted into the threaded nut, after which the placeholder element in the nut and then the rolling elements and the at least one spring element be introduced, and then that the Collar of the threaded spindle facing closure element used becomes.

A Particularly advantageous development provides that during the assembly of the closure elements of the rolling elements and the at least one spring element is a cylindrical one Placeholder element is placed inside the threaded nut, the displaced during insertion of the threaded spindle of this becomes.

The Invention will be described below with reference to two embodiments explained in more detail in connection with the accompanying drawings. In the drawing show:

1 a sectional view of the vehicle brake according to the invention with hydraulically actuated service brake and electromechanically actuated parking brake;

2 a three-dimensional view of the in 1 illustrated vehicle brake;

3 an exploded view of a first embodiment of the transmission that in a vehicle brake 1 and 2 can be used and stops according to the invention and has

4 a second embodiment of the transmission with stops according to the invention.

In the 1 illustrated vehicle brake according to the invention has on the one hand a hydraulically actuated service brake and on the other hand an electromechanically actuated parking brake device. The vehicle brake has a brake housing 29 on, which surrounds the outer edge of a brake disc, not shown, and two brake pads, also not shown. The brake housing 29 forms on its inside a brake cylinder 9 , a brake piston 5 axially displaceable receives. In the between brake cylinder 9 and brake pistons 5 formed operating pressure chamber 6 can be supplied to perform service braking brake fluid, so that builds up a brake pressure, the brake piston 5 axially displaced along a piston longitudinal axis A towards the brake disc. This will be the brake piston 5 facing brake pad pressed against the brake disc, which is in response to the brake housing 29 moves in the opposite direction and thereby also presses the other brake pad against the brake disc.

A parking brake device for performing parking brake operations is electromechanically operable and also acts on the brake piston 5 , This is a transmission 1 provided that the rotational movement of an electromechanical actuator 7 converted into a translational movement and an actuation of the brake piston 5 along the axis A causes. The gear 1 is essentially a threaded spindle 2 and a threaded nut 3 formed by rolling elements 4 communicate with each other. The rolling elements 4 are as balls 4 educated. One with the threaded spindle 2 connected shaft 17 protrudes on the side facing away from the brake disc from the brake housing 29 out and is with the interposition of a two-stage reduction gear from an electromechanical actuator 7 driven, as described below with reference to 2 will be explained in more detail. The on the threaded spindle 2 transmitted rotational motion is about the balls 4 in the thread between threaded spindle 2 and threaded nut 3 located on the threaded nut 3 transferred, which performs a translational movement in the direction of the axis A. This will also the brake piston 5 operated, on which the threaded nut 3 supported. At the same time the threaded spindle is supported 2 about one with the spindle 2 connected collar 27 and a first thrust bearing 18 on the brake housing 29 from. The gear 1 So sets the rotational movement of the electromechanical actuator 7 in a linear motion and is responsible for the generation of the clamping force for performing a parking brake operation.

Upon actuation of the transmission 1 under load, the rolling elements roll 4 in the thread. As a result, a relatively moderately high efficiency of 75% to 90% is achieved. For a load-free operation of the gearbox 1 slip the rolling elements 4 on the other hand, ie until the brake piston 5 assigned brake pad is applied to the brake disc, not shown, slip the balls 4 because this is an almost load-free operation. Only under load do the balls start 4 to roll or unroll. The gear 1 So at the same time acts as an adjustment if the brake pads, not shown, are worn out. The absence of a separate adjusting device or the integration of adjusting and actuating device in a single component is particularly inexpensive and at the same time robust. So that the rolling of the rolling elements 4 under load and slipping with load-free operation of the gearbox 1 is always possible, is a spring element 10 provided, which holds a rolling path for rolling the rolling elements, as described below with reference to 3 is explained in more detail.

The vehicle brake according to the invention is in 2 shown in three-dimensional view. As can be seen, is between the electromechanical actuator 7 a two-stage reduction gear interposed. In the in 2 illustrated embodiment, the two-stage transmission is a two-stage worm gear 11 . 12 educated. Worm gearboxes are a category of helical gearboxes in which, in contrast to the Wälzgetrieben also a sliding portion in the movement is present. Such a worm gear is made up of a helically toothed wheel, the worm, and a helical gear meshing therewith, the worm wheel. The first gear stage, that is the first worm gear 11 , is input side with the output shaft 8th of the electromechanical actuator 7 connected during the second gear stage, that is, the second worm gear 12 , on the output side with the shaft 17 or with the gearbox 1 connected is. As it is in 2 is shown, is a first screw 13 on the output shaft 8th of the electromechanical actuator 7 attached and combs a first worm wheel 14 , A second snail 15 is on the center of rotation of the first worm wheel 14 attached and is set by this in rotation. This second snail 15 again a second worm wheel meshes 16 , the rotation with the shaft 17 is connected and the shaft 17 together with the threaded spindle 2 set in rotation while a translational movement of the threaded nut 3 generated as already described. In order for the application force set in this manner to be maintained during a parking brake operation, a worm gear must be designed to be self-locking. In the present embodiment, the first worm gear 11 an efficiency of 75%, while the second worm gear is designed with an efficiency of 40% self-locking. The cumulative efficiency is thus 30%. The overall reduction of the two-stage reduction gearbox 11 . 12 in combination with the gearbox 1 for actuating the brake piston 5 is on the order of 350: 1. At the same time a small axial length of the vehicle brake is achieved.

3 shows the gearbox in an exploded view. It can be seen that the balls 4 in the thread between threaded spindle 2 and threaded nut 3 limited mobility between two stops 21 . 22 are arranged. The attacks 21 . 22 be through two closure elements 21 . 22 formed as will be explained in more detail below. Between the first stop 21 and the balls 4 is a spring element 10 provided that in a load-free operation of the transmission 1 a slipping of the balls 4 and upon actuation of the transmission 1 under load a rolling of the balls 4 allows, as the spring element 10 acts as a buffer and holds a Abrollweg or Wälzweg for the balls. As in 3 the attacks are displayed 21 . 22 formed by two annular spiral segments whose circle diameter before mounting in the thread greater than the circular inner diameter of the threaded nut 3 is. The annular spiral segments are made of an elastic material, that is, they can be compressed by elastic deformation. When assembling these annular spiral segments in the thread, they are compressed and due to the elastic deformation, the annular spiral segments are frictionally in the threaded nut after the successful installation 3 positioned. The closure elements designed as annular spiral segments 21 . 22 thus support non-positively with its outer circumference on the threaded nut 3 and simultaneously have no point of contact with the spindle 2 so that they can continue to rotate without friction losses. The right in the drawing closure element 21 serves as a stop at the same time 21 for the at least one spring element 10 ,

In 4 an alternative embodiment is shown: that the closure elements 21 . 22 are formed by two rings, which during assembly in a designated groove 23 . 24 pressed or caulked and are based on the mounting nut on the nut 3 from and are positively positioned in this.

An advantage of in 3 and 4 illustrated closure elements 21 . 22 lies in the simple assembly of the gearbox 1 as based on 3 is explained in more detail. In an assembly process, first the left in the figure closure element 22 into the threaded nut 3 used. Subsequently, in the drawing from the left a cylindrical placeholder element in the threaded nut 3 introduced, which ensures that the bullets 4 and the at least one spring element 10 not before inserting the threaded spindle 2 fall out. Subsequently, the balls 4 and the at least one spring element 10 in the thread of the threaded nut 3 This is the last thing that will happen to the collar 20 facing closure element 21 into the threaded nut 3 used. The insertion of the second closure element 21 into the threaded nut 3 takes place due to a possible bias of the spring element 10 rotationally. The placeholder element is the last assembly step, the screwing of the threaded spindle 2 into the threaded nut 3 from the threaded spindle 2 repressed.

An advantage of the present invention is the simplified assembly with the closure elements 21 . 22 look at, as well as the fact that in the nut 3 no holes must be set and it can therefore be made easier.

1

transmission

2

spindle or threaded spindle

3

threaded nut

4

rolling elements or balls

5

brake pistons

6

hydraulic Working pressure chamber

7

electromechanical actuator

8th

output shaft

9

brake cylinder

10

first spring element

11

first worm gear

12

second worm gear

13

first slug

14

first worm

15

second slug

16

second worm

17

shaft

18

first axial bearing

19

brake housing

20

collar

21

first Stop / first closure element

22

second Stop / second closure element

23

groove

24

groove

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10150803 B4 [0002]
• - DE 102004038951 A1 [0002]
• FR 2337285 [0003]

Claims (7)

Combined vehicle brake having a hydraulically actuated service brake and an electromechanically operable parking brake device, wherein in a brake housing (in 29 ) a hydraulic operating pressure chamber ( 6 ) of a brake piston ( 5 ) is limited, which is acted upon for carrying out service braking with hydraulic pressure medium, so that the brake piston ( 5 ) is operable to achieve a braking action along a piston longitudinal axis (A), and wherein the parking brake device on the brake piston ( 5 ) by means of a transmission ( 1 ) acts by the transmission ( 1 ) the rotational movement of an electromechanical actuator ( 7 ) in a translational movement and an actuation of the brake piston ( 5 ) causes to perform parking brake operations and holds in the actuated position, wherein the transmission ( 1 ) a threaded spindle ( 2 ) and a threaded nut ( 3 ), which has a plurality of rolling elements which are limitedly movable in the thread between two stops ( 4 ) are in contact with each other, wherein at least one spring element ( 10 ) between the rolling elements ( 4 ) and a stop is arranged and in a load-free operation of the transmission ( 1 ) a sliding of the rolling elements ( 4 ) and when actuating the transmission ( 1 ) under load a rolling of the rolling elements ( 4 ), characterized in that the stops by two closure elements ( 21 . 22 ) whose diameter is greater than the inner diameter of the threaded nut ( 3 ) and due to an elastic deformation frictionally in the threaded nut ( 3 ) are positioned. Combined vehicle brake according to claim 1, characterized in that the closure elements ( 21 . 22 ) are formed by two rings, which in a designated groove ( 23 . 24 ) are pressed or caulked and after installation in the threaded nut ( 3 ) are positioned. Combined vehicle brake according to claim 1, characterized in that the closure elements ( 21 . 22 ) are formed by annular spiral segments whose circle diameter before assembly is greater than the inner diameter of the threaded nut ( 3 ) and after assembly due to an elastic deformation in the threaded nut ( 3 ) are positioned. Combined vehicle brake according to one of claims 1 to 3, characterized in that the closure elements ( 21 . 22 ) are formed such that the threaded spindle ( 2 ) non-contact with respect to the closure elements ( 21 . 22 ) is movable. Method for assembling a combined vehicle brake according to one of the preceding claims, characterized in that the following method steps are carried out: - inserting a closure element ( 21 . 22 ) in the threaded nut ( 3 ); - Inserting a cylindrical placeholder element in the threaded nut ( 3 ); - insertion of the rolling elements ( 4 ) and the at least one spring element ( 10 ); Inserting the second closure element ( 21 . 22 ) in the threaded nut ( 3 ) and - insertion of the threaded spindle ( 2 ) in the threaded nut ( 3 ) and displacing the placeholder element. A method according to claim 5, characterized in that first the brake piston ( 5 ) facing closure element ( 22 ) in the threaded nut ( 3 ) is inserted, after which first the placeholder element in the threaded nut ( 3 ) and then the rolling elements ( 4 ) and the at least one spring element ( 10 ) and then that the collar ( 27 ) of the threaded spindle ( 2 ) facing closure element ( 21 ) is used. Method according to claim 6, characterized in that during the assembly of the closure elements ( 21 . 22 ), the rolling elements ( 4 ) and the at least one spring element ( 10 ) a cylindrical placeholder element within the threaded nut ( 3 ) is arranged, which during insertion of the threaded spindle ( 2 ) is displaced by this.