PRIMARY PISTON, MASTER BRAKE CYLINDER INCLUDING THE PRIMARY PISTON, GEAR DEVICE, AND BRAKE PRESSURE GENERATOR

Abstract

The present invention relates to a primary piston (10) for a master brake cylinder (14) or a gear unit (26), having on a first side (10a) a first recess (20) into which at least a partial area facing towards the primary piston (10) of a primary spring (12) of a master brake cylinder (14) carrying or cooperating with the primary piston (10) can be inserted or mounted, and on a second side (10b) of the primary piston (10) facing away from the first side (10a) a second recess (28) is formed into which at least a partial area facing towards the primary piston (10) of a primary spring (12) of a master brake cylinder (14) carrying or cooperating with the primary piston (10) can be inserted or mounted, At least a partial area of ​​a spindle (22) of a gearing (26) equipped with or cooperating with the primary piston (10), facing towards the primary piston (10), and at the same time at least a partial area of ​​a nut (24) of the gearing (26), arranged on the spindle (22), facing towards the primary piston (10), are insertable and / or attached, such that a first recess (20) formed in a first side (10a) of the primary piston (10) surrounds at least a partial area of ​​the second recess (28), facing towards the first side (10a).

Description

[Technical Field]

[0001] The present invention relates to a primary piston for a master brake cylinder or gearing, as well as to a master brake cylinder for a brake-by-wire braking system, a gearing for a brake-by-wire braking system, and a brake pressure generator for a brake-by-wire braking system. [Background technology]

[0002] From the prior art, for example from EP 0 699 043 A1, there is known a primary piston for a master brake cylinder that can cooperate with an electromechanical brake booster arranged upstream of the master brake cylinder, the primary piston being supported on a first side by a primary spring that projects into a recess in the primary piston, whereby a force can be transmitted to a second side of the primary piston facing away from the first side by a spindle and a nut of the electromechanical brake booster. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 102017203559A1 Summary of the Invention

[0004] The present invention provides a primary piston for a master brake cylinder or gearing having the features of claim 1, a master brake cylinder for a brake-by-wire brake system having the features of claim 5, a gearing for a brake-by-wire brake system having the features of claim 7, and a brake pressure generator for a brake-by-wire brake system having the features of claim 10.

[0005] The present invention provides a primary piston, the preferred configuration of which allows a reduction in the design length of a brake pressure generator equipped with the primary piston and combining the functions of a master brake cylinder and a gear unit. The compactness of a brake pressure generator equipped with a primary piston according to the present invention can also be improved by the fact that at least a partial area of ​​the brake pressure generator spindle facing the primary piston and, at the same time, at least a partial area of ​​the brake pressure generator nut facing the brake piston can be inserted into and / or is inserted into the second recess of the primary piston. The reduction in the design length of the brake pressure generator achieved by the present invention, or the increased compactness of its design, allows a reduction in the design space of a vehicle / automobile constructed using it.

[0006] In one preferred embodiment of the primary piston, at least a partial section of the spindle facing the primary piston is mountable or attached to the second recess, while at the same time at least a partial section of the nut that rotates about the spindle facing the primary piston is insertable into the second recess, In this way, the design space created by the primary piston can be utilized for the spindle with the nut that cooperates therewith.

[0007] In another preferred embodiment of the primary piston, at least a partial area of ​​the nut facing the primary piston is mountable or attached in the second recess, while at the same time at least a partial area of ​​the rotationally moving spindle facing the primary piston is insertable into the second recess. As will become clear below, in the embodiment of the primary piston described here, the nut cooperating therewith can be (almost) completely "sunken" in the second recess, which causes a significant reduction in the design length of the brake pressure generator equipped therewith.

[0008] If at least the partial area of ​​the nut facing the primary piston is mounted in the second recess, the nut can be a recirculating ball nut or a threaded nut, thus allowing for the application of any type of nut for cooperation with the primary piston according to the invention.

[0009] The advantages described above are also ensured in a master brake cylinder for a brake-by-wire brake system having a primary piston of this type and a primary spring cooperating with the primary piston, wherein at least a partial area of ​​the primary spring facing towards the primary piston is mounted in a first recess of the primary piston.

[0010] The master brake cylinder housing is preferably a gravity die casting, which allows the master brake cylinder housing to be manufactured at relatively low cost.

[0011] The advantages described above are also realized in a gearing for a brake-by-wire brake system having a corresponding primary piston and a spindle and a nut arranged on the spindle which cooperate with the primary piston, wherein at least a partial area of ​​the spindle facing the primary piston or at least a partial area of ​​the nut facing the primary piston is attached to a second recess in the primary piston.

[0012] In a preferred development, if at least a partial section of the spindle facing the primary piston is mounted in the second recess of the primary piston, at least one torque-bearing component can be mounted on or configured to support the primary piston against an inner wall of the gear housing of the gear device. Alternatively, if at least a partial section of the nut facing the primary piston is mounted in the second recess of the primary piston, at least one torque-bearing component can be mounted on or configured to support the nut against an inner wall of the gear housing of the gear device. In both of these cases, the at least one torque-bearing component can prevent undesired co-rotational movement of the primary piston.

[0013] Furthermore, a brake pressure generation for a brake-by-wire brake system equipped with a primary piston of this type, a master brake cylinder and its primary spring cooperating with the primary piston, in which at least a partial area of ​​the primary spring facing the primary piston is attached in a first recess of the primary piston, and a gear device cooperating with the primary piston, having a spindle and a nut arranged on the spindle, in which at least a partial area of ​​the spindle facing the primary piston or at least a partial area of ​​the nut facing the primary piston is attached in a second recess of the primary piston, also has the advantages described above.

[0014] In one preferred embodiment of the brake pressure generator, the master brake cylinder housing is a gravity die casting, which allows the master brake cylinder housing to be manufactured at relatively low cost.

[0015] Alternatively or additionally, the housing of the master brake cylinder may be screwed to the gear housing of the gear unit, which simplifies repair or replacement of the master brake cylinder.

[0016] Further features and advantages of the present invention are described below with reference to the drawings, in which: [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing a first embodiment of a primary piston or of a brake pressure generator equipped with the primary piston; [Figure 2] 2 is a schematic diagram showing a second embodiment of a primary piston or of a brake pressure generator equipped with the primary piston; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] FIG. 1 shows a schematic diagram of a first embodiment of a primary piston or of a brake pressure generator equipped with it.

[0019] A primary piston 10, shown diagrammatically in Fig. 1, is shaped on a first side 10a such that a primary spring 12 of a master brake cylinder 14, which is equipped with or cooperates with the primary piston 10, can / is in mechanical contact with the primary piston 10 on the first side 10a. By way of example, in the embodiment of Fig. 1, the primary piston 10 can / is supported by a secondary piston 16 of the master brake cylinder 14 by the primary spring 12, and the secondary piston 16 can / is supported by an inner wall of the master brake cylinder 14 by a secondary spring 18. However, alternatively, the primary piston 10 can / is supported by the inner wall of the master brake cylinder 14 by the primary spring 12. A first recess 20 is formed on the first side 10a of the primary piston 10, into which at least a partial section of the primary spring 12 facing the primary piston 10 can be inserted / mounted. The first side 10a of the primary piston 10 can thus be referred to as a stepped side or a stepped inner contour side. The first recess 20 on the first side 10a of the primary piston 10 is preferably configured as an annular recess. The inner diameter of the annular configured first recess 20 can be equal to or smaller than the inner diameter of the primary spring 12, whereas the outer diameter of the annular configured first recess 20 is preferably equal to or larger than the outer diameter of the primary spring.

[0020] Furthermore, on a second side 10b facing away from the first side 10a, the primary piston 10 is shaped such that it can transmit / is capable of transmitting force to the primary piston 10 via a spindle 22 and a nut 24 arranged on the spindle 22 of a gearing 26 that is equipped with or cooperates with the primary piston 10. This force can be transmitted to the spindle 22 and the nut 24 cooperating therewith by, for example, a motor (not shown) and then further transmitted via the spindle 22 and the nut 24 to the primary piston 10. This motor can be the motor of the gearing 26 or a motor externally connected to the gearing 26. The spindle 22 and the nut 24 jointly constitute a rotational-translational gear stage of the gearing 26. The rotational-translational gear stage constituted by the spindle 22 and the nut 24 can in particular be the final gear stage of the force transmission chain of the gearing 26. The gearing 26 may be at least part of an electromechanical brake booster.

[0021] As shown graphically in FIG. 1 , a second recess 28 is formed in the second side 10b of the primary piston 10, into which at least a partial section of the spindle 22 facing the primary piston 10 and, simultaneously, at least a partial section of the nut 24 facing the primary piston 10 can be inserted and / or attached. The second side 10b of the primary piston 10 can also be referred to as a stepped side or stepped inner contour side of the primary piston 10. The second recess 28 is configured with a large volume so that the first recess 20 formed in the first side 10a of the primary piston 10 surrounds at least a partial section of the second recess 28 facing the first side 10a. In other words, the second recess 28 of the primary piston 10 can be said to extend from the second side 10b to the piston subvolume 10c of the primary piston 10 surrounded by the first recess 20. A covered area / piston bottom 10d of the piston partial volume 10c formed on the first side 10a of the primary piston 10 may prevent brake fluid from entering the master brake cylinder 14 into the second recess 28 of the primary piston 10. The second recess 28 of the primary piston 10 preferably extends from the second side 10b into the primary piston 10 to such an extent that the partial area of ​​the second recess 28 facing the first side 10a of the primary piston 10 is separated from the first side 10a of the primary piston 10 only by the covered area 10d. The thickness of the covered area 10d along the maximum extension of the primary piston 10 may be, for example, less than one tenth of the maximum extension of the primary piston 10, in particular less than one fifteenth of the maximum extension of the primary piston 10.

[0022] The shape of the primary piston 10 creates the possibility for at least a partial area of ​​the spindle 22 facing towards the primary piston 10 and for at least a partial area of ​​the nut 24 facing towards the primary piston to retract, so that the design space of the primary piston 10 can be shared for at least partial areas of the spindle 22 and the nut 24. Thus, as can be seen in Figure 1, the preferred shape of the primary piston 10 described above allows a clear reduction in the design length of the brake pressure generator having the functions of the brake booster 14 and the gearing 26.

[0023] Optionally, the first side 10a of the primary piston 10 may further comprise an edge region 10e surrounding the first recess 20 of the primary piston 10. The second recess 28 on the second side 10b of the primary piston 10 may include an outer region 28a adjacent to the second side 10b and an inner region 28b located on the outer region 28a facing away from the second side 10b. The inner region 28b of the second recess 28 may extend into the piston subvolume 10c surrounded by the first recess 20. The maximum diameter of the inner region 28b is preferably smaller than the minimum diameter of the outer region 28a of the second recess 28. This simplifies the configuration of the inner region 28b of the second recess 28 even within the piston subvolume 10c of the primary piston 10 surrounded by the first recess 20.

[0024] In the embodiment of Fig. 1, at least a partial section of the spindle 22 facing the primary piston 10 is mountable / mounted in the second recess 28. To this end, the maximum diameter of the inner section 28b of the second recess 28 may be (approximately) equal to the maximum diameter of the partial section of the spindle 22 mounted in the inner section 28b. While the spindle 22 is fixed to the primary piston 10, the nut 24 can be excited to rotate about the spindle 22 by the operation of a motor. In particular, in the embodiment of Fig. 1, the nut 24 is supported via a bearing 30. The rotational movement of the nut 24 linearly adjusts the spindle 22 and the primary piston attached thereto, with the second recess 28 / its outer section 28a of the adjusted primary piston 10 receiving or releasing the rotating partial section of the nut 24 facing the primary piston 10. Therefore, the minimum diameter of the outer region 28a of the second recess 28 is preferably larger than the maximum diameter of the partial region of the nut 24 that can be inserted into the outer region 28a.

[0025] 1, at least one torque-bearing component 32 is further attached to or configured on the primary piston 10. By means of the at least one torque-bearing component 32, the primary piston 10 can be supported on an inner wall of a gear housing 34 of the gearing 26 in such a way that an undesired co-rotational movement of the primary piston 10 together with the rotating nut 24 does not occur.

[0026] For further features and advantages of the brake pressure generator of FIG. 1, see the following description.

[0027] FIG. 2 shows a schematic diagram of a second embodiment of the primary piston or of the brake pressure generator equipped with it.

[0028] Unlike the embodiments described above, in the primary piston 10 of Fig. 2, at least a partial section of the nut 24 facing the primary piston 10 is mountable / mounted in the second recess 28 / its outer section 28a. To this end, the maximum diameter of the outer section 28a of the second recess 28 is preferably (substantially) equal to the maximum diameter of the partial section of the nut 24 mounted in the second recess 28 / its outer section 28a. While the nut 24 is fixed to the primary piston 10, the spindle 22 can be excited to rotate relative to the primary piston 10 about its longitudinal axis by the operation of a motor. During the rotational movement, at least a partial section of the rotating spindle 22 facing the primary piston 10 rotates into or out of the second recess 28 / its inner section 28b. Therefore, the minimum diameter of the inner section 28b of the second recess 28 is preferably greater than the maximum diameter of the partial section of the spindle 22 that can be inserted into the inner section 28b. To support the axial force, the spindle 22 may be supported via a bearing 36.

[0029] 1 and 2, it is clear that in the embodiment of FIG. 1, the spindle 22 extends into the second recess 28 up to the covered area 10d. Therefore, the maximum stroke of the spindle 22 and the nut 24 can be completely accommodated within the design space of the primary piston 10. The brake pressure generator of FIG. 2 therefore has a shorter design length than the embodiment of FIG. 1. In this way, the compactness of the design of the brake pressure generator of FIG. 2 is further optimized.

[0030] In a preferred development, at least one torque-bearing component 38 is further attached / configured to the nut 24 of the brake pressure generator of Fig. 2, by means of which the nut 24, and thus also the primary piston 10, is supported on the inner wall of the gear housing 34 of the gear device 26. In this way, undesired co-rotational movement of the primary piston 10 together with the rotating spindle 22 is also prevented in the brake pressure generator of Fig. 2.

[0031] For other components and characteristics of the brake pressure generator of FIG. 2, please refer to the description of the embodiment of FIG. 1 and the following description.

[0032] All of the brake pressure generators described above can be applied to brake-by-wire brake systems, servo brakes, or power brakes, but the applicability of the brake pressure generators described above is not limited to the applications listed here.

[0033] In any of the brake pressure generators described above, the nut 24 can also be called a spindle nut. The nut 24 can be, for example, a recirculating ball nut or a threaded nut. The spindle 22 can be understood to be a threaded spindle, a recirculating ball spindle, or a rack.

[0034] The housing 40 of the master brake cylinder 14 may be / can be screwed to the gear housing 34 of the gear unit 26 by at least one screw 42. This simplifies the assembly of the master brake cylinder 14 to the gear unit 26 and allows for quick and easy replacement of the master brake cylinder 14 during maintenance work. Furthermore, in this case, the master brake cylinder 14 can be manufactured as a separate module, separately from the gear unit 26. The housing 40 of the master brake cylinder 14 is preferably a gravity die casting, in particular a gravity die casting made of aluminum. In this case, the master brake cylinder 14 can be manufactured relatively inexpensively.

[0035] All of the brake pressure generators described above can be utilized to implement a dual-circuit brake system. However, it should be noted that the master brake cylinder 14 of the brake pressure generator described above is configured as a tandem master brake cylinder by way of example only. Alternatively, the master brake cylinder 14 may be configured for hydraulic connection of only a single brake circuit.

[0036] It should be pointed out again that all the brake pressure generators described above have a compact structure and can be manufactured at low cost, due to the favorable utilization of the design space of the primary piston 10, without the expense of undesired intrusion of the spindle 22 into the interior space of the vehicle in which they are installed. [Explanation of symbols]

[0037] 10 Primary piston 10a First Side 10b Second Side 12 Primary spring 14 Master brake cylinder 20 First recess 22 Spindle 24 Nut 26 Gearing 28 Second recess 32 Torque Support Components 34 Gear housing 38 Torque Support Components 40 Housing

Claims

1. A primary piston (10) for a master brake cylinder (14) or gearing (26), comprising: a primary piston having a first recess (20) on a first side (10a) into which at least a partial section facing towards said primary piston (10) of a primary spring (12) of a master brake cylinder (14) carrying or cooperating with said primary piston (10) can be inserted or is mounted, a second recess (28) is formed on a second side (10b) of the primary piston (10) facing away from the first side (10a), into which at least a partial section of a spindle (22) of a gearing device (26) carrying or cooperating with the primary piston (10) facing towards the primary piston (10) and simultaneously at least a partial section of a nut (24) of the gearing device (26) arranged on the spindle (22) facing towards the primary piston (10) can be inserted and / or attached; 1. A primary piston, comprising: a first recess (20) formed in the first side (10a) of the primary piston (10) surrounding at least a partial area of ​​the second recess (28) facing the first side (10a).

2. 2. The primary piston (10) according to claim 1, wherein at least a partial section of the spindle (22) facing the primary piston (10) is attachable or attached to the second recess (28), while at the same time, at least a partial section of the nut (24) rotating about the spindle (22) facing the primary piston (10) is insertable into the second recess (28).

3. 2. The primary piston (10) according to claim 1, wherein at least a partial section of the nut (24) facing the primary piston (10) is attachable or attached to the second recess (28), while at the same time at least a partial section of the rotationally moving spindle (22) facing the primary piston (10) is insertable into the second recess (28).

4. 4. The primary piston (10) of claim 3, wherein at least a partial area of ​​the nut (24) facing the primary piston (10) is attached to the second recess (28), and the nut (24) is a recirculating ball nut or a threaded nut.

5. In a master brake cylinder (14) for a brake-by-wire brake system, A primary piston (10) according to any one of claims 1 to 4; and a primary spring (12) cooperating with the primary piston (10), A master brake cylinder, wherein at least a partial section of the primary spring (12) facing the primary piston (10) is attached to the first recess (20) of the primary piston (10).

6. 6. The master brake cylinder (14) of claim 5, wherein the housing (40) of the master brake cylinder (14) is a gravity die casting.

7. A gear unit (26) for a brake-by-wire braking system, comprising: A primary piston (10) according to any one of claims 1 to 4; the spindle (22) and the nut (24) disposed on the spindle (22) cooperating with the primary piston (10); At least a partial area of ​​the spindle (22) facing the primary piston (10), or at least a partial area of ​​the nut (24) facing the primary piston (10), is attached to the second recess (28) of the primary piston (10).

8. 8. The gear device (26) according to claim 7, wherein at least a partial section of the spindle (22) facing the primary piston (10) is attached to the second recess (28) of the primary piston (10), and at least one torque-bearing component (32) is attached to or configured on the primary piston (10), whereby the primary piston (10) is supported on an inner wall of a gear housing (34) of the gear device (26).

9. 8. The gear device (26) of claim 7, wherein at least a partial area of ​​the nut (24) facing the primary piston (10) is attached to the second recess (28) of the primary piston (10), and at least one torque-bearing component (38) is attached to or configured on the nut (24) so ​​that the nut (24) is supported on an inner wall of a gear housing (34) of the gear device (26).

10. In a brake pressure generator for a brake-by-wire brake system, A primary piston (10) according to any one of claims 1 to 4; a master brake cylinder (14) and its primary spring (12) cooperating with the primary piston (10), at least a partial area of ​​the primary spring (12) facing the primary piston (10) being attached to the first recess (20) of the primary piston (10); a gear device (26) that cooperates with the primary piston (10) and has a spindle (22) and a nut (24) arranged on the spindle (22), and at least a partial area of ​​the spindle (22) that faces the primary piston (10) or at least a partial area of ​​the nut (24) that faces the primary piston (10) is attached to the second recess (28) of the primary piston (10).

11. 11. The brake pressure generator of claim 10, wherein the housing (40) of the master brake cylinder (14) is a gravity die casting.

12. 11. The brake pressure generator according to claim 10, wherein the housing (40) of the master brake cylinder (14) is screwed to the gear housing (34) of the gear unit (26).

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