Assembly, method for manufacturing the assembly, and electronic commutated motor comprising the assembly

Abstract

The present invention relates to an assembly (10) comprising a machine shaft (12), a second rolling bearing (20) having an inner ring (22) and an outer ring (24) for rotatably supporting the machine shaft (12) in a housing block (16), and a signal generator (40) of a rotor position sensor having a generator element (44) and a holding cup (42) for electrically detecting the rotation angle of the machine shaft (12). 【Means for solving the problem】 An annular gap exists between a fixed portion (46) of the holding cup (42) and the circumference of the machine shaft (12), and a fastening ring (52) is inserted into this annular gap. The signal generator (40) is attached to the machine shaft (12) by this fastening ring so as to be non-rotatable and axially immovable. According to the present invention, the fastening ring (52) projects axially from the holding cup (42) by an end of the fastening ring, and is axially supported by the inner ring of the rolling bearing (20) by this projecting end. The present invention further relates to a method of assembling the assembly (10) and an electronic rectifier motor equipped with the assembly (10).

Description

Technical Field

[0001] The present invention relates to an assembly according to the features of the preamble of claim 1, a method for manufacturing an assembly according to the features of the preamble of claim 7, and an electronically commutated motor according to the features of the preamble of claim 8.

Background Art

[0002] Attributively corresponding assemblies are known from the prior art. For example, Patent Document 1 discloses an electronically commutated machine having such an assembly, which is provided as a drive unit for a brake pressure generator of an electronically slip-controllable brake system of an automobile.

[0003] In this known machine, a signal generator is non-rotatably fixed to one end of a machine shaft. The signal generator rotating with the machine shaft forms, together with a signal receiver fixedly arranged in a housing block, a sensor system for detecting the rotational position of the machine shaft. The position signal is transferred to an electronic control unit and evaluated there. For example, this position signal can be used for the necessary optimized electrical control of the stator of an electric machine and / or to determine the operating distance of a piston of a pressure generator driven by the machine shaft, possibly via a transmission arranged downstream. From the distance the piston has advanced, the volume of brake fluid displaced into a connected brake circuit can be determined, from which the expected brake pressure in the brake circuit can be determined.

[0004] Patent Document 1 proposes a force-coupling shaft-hub connection using a fastening ring or a tolerance ring for non-rotatably and axially immovably connecting the signal generator to the machine shaft. This tolerance ring is located in an annular gap between the outer circumference of the machine shaft and the inner circumference of a holding cup of the signal generator fitted over the machine shaft. The latter carries a magnet as a generator element.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

[0006] The present invention improves this known assembly by also being used to axially bias the raceways of a rolling bearing in which a tolerance ring is additionally provided to pivotally support a machine shaft. For this purpose, according to the present invention, the fastening ring or tolerance ring has one end protruding axially from the fastening portion (Befestigungsabschnitt) of the holding cup of the signal generator and is supported by the inner ring of the rolling bearing by this protruding end. The clamping force (Verspannkraft) of the rolling bearing is provided by a spring element that is arranged on the opposite side of the rolling bearing and loads a load on the assigned outer ring of the rolling bearing.

[0007] Due to the intended support of the fastening ring or tolerance ring on the inner ring of the rolling bearing, when assembling the signal generator, the axial support of the fastening ring or tolerance ring for the purpose of avoiding movement relative to the machine shaft can be omitted. This is particularly advantageous when the available structural space makes it difficult or even prevents the use of support tools, as is common in automotive components. The joining of the signal generator can be carried out in a concealed state (verdeckt), i.e., without measures to monitor such an inconvenient relative movement between the tolerance ring and the machine shaft. The rolling bearing is fixed axially, i.e., in the longitudinal direction of the shaft, between the fastening ring or tolerance ring and the shaft shoulder provided on the machine shaft in the assembled state. For this purpose, additional parts such as snap rings are no longer required.

[0008] Other advantages or advantageous developments of the present invention will become apparent from the dependent claims or the following description.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2a

Figure 2b

Figure 2c

Figure 2d

Figure 2e

Figure 2f

Figure 2g

Figure 2h

Figure 2i

Figure 2j

Figure 2k

Embodiments of the Invention

[0010] Embodiments of the present invention are shown in the drawings and will be described in detail in the following description. The drawings include a plurality of figures for this purpose.

[0011] According to FIG. 1, an assembly (10) according to the invention comprises a machine shaft (12) rotatably supported within a shaft hole (14) of a housing block (16). The support is effected by at least two rolling bearings, and FIG. 1 shows only one of them, a so-called second rolling bearing (20). This second rolling bearing (20) is exemplarily formed as a ball bearing sealed on both sides and has an inner ring (22), an outer ring (24), and balls (26) received in the raceway portions between these raceway rings. The second rolling bearing (20) is arranged in the cylindrical portion of a bearing receiving portion (30) of the housing block (16), and the bearing receiving portion opens conically towards the end of the machine shaft (12). An electronic control device (28) is attached to the housing block (16), and the end of the machine shaft (12) extends into this electronic control device. A signal receiver (38) located on the opposite side of the opening of the shaft hole (14) is fixedly arranged in the electronic control device (28).

[0012] The bearing receiving portion (30) ends, on the opposite side of the opening, with a support shoulder (32) formed at right angles to the shaft longitudinal axis. This support shoulder (32) is used as a first axial support portion of a spring element (34) exemplarily formed as a wave washer. The second axial support portion of the spring element (34) forms the side surface of the outer ring (24) of the second rolling bearing (20). The spring element (34) is axially biased and arranged between the two aforementioned support portions in the assembled state.

[0013] The machine shaft (12) has its outer diameter first stepped at a right angle, thereby forming a shaft shoulder (18). At the end of the machine shaft (12), a first shaft portion with a smaller outer diameter is formed. In contrast, a second shaft diameter (Wellendurchmesser) with a larger outer diameter passes through a spring element (34) formed in a ring shape and further extends into the shaft hole (14). A second rolling bearing (20) is accommodated on the first shaft portion with a smaller diameter by the inner diameter of its inner ring (22). This second rolling bearing (20) abuts against the shaft shoulder (18) by the side surface of its inner ring (22). There is a clearance fit (Spielpassung) between the outer diameter of the outer ring (24) of the second rolling bearing (20) and the inner diameter of the bearing housing portion (30), as well as between the inner diameter of the inner ring (22) of the second rolling bearing (20) and the outer diameter of the machine shaft (12). Therefore, the second rolling bearing (20) is arranged in the bearing housing portion (30) to be relatively displaceable with respect to the machine shaft (12) and with respect to the housing block (16) respectively.

[0014] The machine shaft (12) projects from the second rolling bearing (20) in the direction of the opening of the shaft hole (14) by its first shaft portion with a smaller diameter. This projecting shaft portion of the machine shaft (12) forms a fastening portion (36) for a signal generator (40) fixed to the machine shaft (12). For this purpose, the signal generator (40) is sleeve-shaped and includes a holding cup (42) that projects beyond the end of the machine shaft, and a magnet (44) as a generator element carried by the holding cup (42). The signal generator (40) forms a sensor system for detecting the rotational angle of the machine shaft (12) in cooperation with a signal receiver (38) in an electronic control device (28).

[0015] The holding cup (42) of the signal generator (40) is a sleeve-shaped member that is open on both sides and is divided into a fixing portion (Fixierabschnitt) (46) at the tip on the rolling bearing side (Stirnende) and a generator receiving portion (48) for the magnet (44) at the tip on the control device side of the holding cup (42) located on the opposite side thereof. The holding cup (42) has an inner diameter smaller than that of the region of the generator receiving portion (48) in the region of the fixing portion (46), whereby the magnet (44) carried by the generator receiving portion (48) projects radially beyond the end face of the machine shaft (12). The magnet (44) faces the signal receiver (38) directly in the electronic control device (38).

[0016] A push-in flange (50) that is provided circumferentially and projects perpendicularly outward from the holding cup (42) is integrally formed at the end on the rolling bearing side on the fixing portion (36) of the holding cup (42). In the illustrated end position of the holding cup (42), there is a predetermined axial distance between this push-in flange (50) and the facing side surface of the second rolling bearing (20), that is, the holding cup (42) and the second rolling bearing (20) do not contact each other.

[0017] The signal generator (40) is fixed to the machine shaft (12) using a fastening ring (52). This fastening ring (52) fits into the annular gap between the outer diameter of the first, smaller-diameter shaft portion of the machine shaft (12) and the inner diameter of the fixing portion (46) of the holding cup (42). The fastening ring (52) is also known by the term tolerance ring and can be used as a closed, open, or slotted ring.

[0018] According to the present invention, the fastening ring (52) projects axially from the fixing portion (46) of the holding cup (42) by the end facing the second rolling bearing (20) and is axially supported on the side surface of the inner ring (22) of the second rolling bearing (20).

[0019] By forming the raceway portions for the rolling elements / balls (26) on both the inner ring (22) and the outer ring (24) of the second rolling bearing (20), two raceway rings are connected to each other in a form-fitting manner via the balls (26) and are axially displaceable from each other due to the inevitable bearing clearance caused by manufacturing. The spring element (34) applies a biasing force (Vorspannkraft) to the outer ring (24) of the rolling bearing (20), thereby clamping the two raceway rings of the rolling bearing (20) against each other. By tightly supporting the machine shaft (12) in the housing block (16), a particularly low-noise and wear-resistant operation of the machine equipped with this is achieved.

[0020] When manufacturing the assembly unit, the support tool for securely fixing the position of the fastening ring or tolerance ring (52) on the machine shaft (12) during the assembly of the signal generator (40) can be omitted. Since the fastening ring (52) abuts axially against the inner ring (22) of the second rolling bearing (20), making relative movement in the axial direction or the shaft longitudinal axis direction between the fastening ring (52) and the machine shaft (12) impossible, the external fitting of the holding cup (42) of the signal generator (40) to the fastening ring (52) can be carried out in a concealed state.

[0021] Figure 2 shows the manufacture of an electric motor equipped with the assembly (10) according to the invention. In the individual sub-figures 2a to 2k, the individual successive assembly steps are shown schematically in a simplified manner. Parts corresponding to each other in Figure 1 and the sub-figures of Figure 2 are consistently assigned the same reference signs.

[0022] Figure 2a shows the initial state at the start of the assembly method. In this initial state, a housing block (16) is provided, and a shaft hole (14) passing through the housing block is formed in the housing block. An electric machine with a stator housing (60), in this example an electric motor, is attached to one of the outer surfaces of the housing block (16) by, for example, a screw connection not shown in the figure. The stator housing (60) houses a stator (62) and a rotor (64) rotatably accommodated inside the stator (62). The rotor (64) is firmly connected to the machine shaft (12), and the machine shaft extends into the shaft hole (14). The machine shaft (12) protrudes out from the housing block (16) on the opposite side of the rotor. This side of the housing block (16) is provided for attaching the electronic control device (reference numeral 28; Figure 1).

[0023] In order to rotatably support the machine shaft (12) or the rotor (64) firmly connected thereto in the housing block (16), a first rolling bearing or ball bearing (66) is provided. The inner ring (68) of the first rolling bearing (66) is firmly pressed against the machine shaft (12), while the outer ring (70) of the first rolling bearing (66) is firmly pressed into the first bearing seat (72) of the housing cover (74) covering the stator housing (60) on the circumferential side by the end portion facing the rotor (64), and is firmly pressed into the second bearing seat (76) on the outer side of the housing block (16) on the circumferential side by the end portion on the side opposite to the rotor (64).

[0024] An output element (78) is mounted on the portion of the machine shaft (12) pivotally supported inside the shaft hole (14). In that case, this can be a spindle nut, gear, eccentric body, cam, etc. The output element (78) and the machine shaft (12) may be integrally formed, or alternatively, they may be individual parts firmly connected to each other.

[0025] The end of the shaft hole (14) of the machine housing, which is located on the opposite side of the stator housing (69), has a support shoulder (32) facing the opening direction of this shaft hole (14).

[0026] According to FIG. 2b, a spring element (34) in the form of a ring and surrounding the machine shaft (12) is inserted into the shaft hole (14). In the assembled state, this spring element (34) rests on a support shoulder (32) formed inside the shaft hole (14).

[0027] FIG. 2c shows a second rolling bearing or ball bearing (20), which is externally fitted to the machine shaft (12) by its inner ring (22) until it rests on the spring element (32) by the leading side surface of the outer ring (24) according to FIG. 2d. The second rolling bearing (20) abuts against the wall of the bearing housing (30) on the circumferential side. Although not visible in FIGS. 2c and 2d, there is a first clearance fit existing between the inner ring (22) of the second rolling bearing (20) and the machine shaft (12), or a second clearance fit existing between the outer ring (24) of the second rolling bearing (20) and the wall of the bearing housing (30).

[0028] In the step according to FIG. 2e, the fastening ring or tolerance ring (52) is assembled to the machine shaft (12). For this purpose, first this fastening ring (52) is passed through the free end of the machine shaft (12), and then it is displaced along the shaft circumference until the leading end contacts the inner ring (22) of the second rolling bearing (20). For this purpose, since the fit between the fastening ring (52) and the machine shaft (12) is designed as a clearance fit or an intermediate fit (Uebergangspassung), it is necessary to apply a slight axial force in the direction of the shaft longitudinal axis.

[0029] Subsequently, according to FIG. 2f, the magnet (44) of the signal generator (40) is placed in the generator receiving portion (48) of the holding cup (42) provided therefor, and is attached, for example, by sticking or caulking to the holding cup (42). Subsequently, the pre-assembled unit of the holding cup (42) and the magnet (44) is centered on the outer periphery of the fastening ring (52), and is at least partially pressed against the fastening ring or the tolerance ring (52) using a pressing tool (80) (FIG. 2g). For this purpose, the pressing tool (80) acts on the back surface of the pressing flange (50) that protrudes radially from the holding cup (42) when viewed in the pressing direction.

[0030] As the holding cup (42) and the fastening ring (52) start to overlap, the pressing force increases. Based on this pressing force, the fastening ring (52) moves relative to the machine shaft (12) facing the inside of the shaft hole (14). At this time, in order to move the second rolling bearing (20) in contact forward, the spring element (34) located between the support shoulder (32) of the housing block (16) and the outer ring (24) of the second rolling bearing (20) is biased. When the side surface of the inner ring (22) of this second rolling bearing (20) mechanically abuts against the shaft shoulder (18) of the machine shaft (12), the second rolling bearing (20) reaches its end position (FIG. 2h).

[0031] Next, according to FIG. 2i, due to the continuously acting pressing force, the unit of the holding cup (42) and the magnet (44) is further moved relative to the fastening ring (52) until the maximum overlap between the holding cup (42) and the fastening ring (52) is achieved. Thereby, the pressing process of the signal generator (40) is completed. In that case, the fastening ring (52) is radially biased by the holding cup (42), and is firmly fixed to the machine shaft (12) based on this biasing.

[0032] When the signal generator (40) is pressed against the clamping ring (52), the pressing force acts on the inner ring (22) of the second rolling bearing (20) via the clamping ring (52). In that case, in the opposite axial direction, a force is applied to the assigned outer ring (24) of the second rolling bearing (20) by a spring element (34) supported on the support shoulder (32) of the housing block (16). These forces acting in opposite directions on the respective raceways of the second rolling bearing (20) clamp the raceways against each other, thereby reducing the bearing clearance that initially existed, i.e., the clearance of the rolling elements or balls (26) in the raceway portions of the inner ring (22) or the outer ring (24) to at least approximately zero. In that case, the inner ring (22) of the second rolling bearing (20) projects further into the shaft hole (14) than the outer ring (24).

[0033] In the step shown by FIG. 2k, the pressing process of the signal generator (40) against the clamping ring (52) is completed. The load of the pressing tool (80) is released and it is removed from the retaining cup (42). In that case, the spring element (34), which loads the energized outer ring (24) of the second rolling bearing (20), relaxes. Thus, the outer ring (24) of the second rolling bearing (20) moves in the direction of the opening of the shaft hole (14) within the assigned bearing housing (30), and in so doing, moves the assigned inner ring (22) together while maintaining the mutual clamping existing in the raceways.

[0034] The latter is firmly clamped between the clamping ring (52) and the shaft shoulder (18) of the machine shaft (12), whereby the above-mentioned axial movement of the outer ring (24) is finally transmitted to the entire machine shaft (20).

[0035] Since the inner ring (68) of the first rolling bearing (66) arranged on the rotor side is firmly pressed against the machine shaft (12) as described above, this inner ring (68) also follows the axial movement of the machine shaft (12) and thus moves relative to the outer ring (70) which is also firmly accommodated in the bearing seats (72, 74).

[0036] As a result, the mechanical shaft (12) is supported such that the raceways (22, 24; 68, 70) of the two rolling bearings (20; 66) are clamped to each other. Such a biased support of the mechanical shaft (12) in the housing block (16) is characterized in that, in particular, the machine equipped with this assembly unit (10) is low-noise and wear-resistant.

[0037] Of course, it is conceivable to make changes or additions to the above embodiments without departing from the idea of the invention claimed in the independent claims.

[0038] In this connection, it should be mentioned that the present invention is not limited to application to vehicle brake systems and can generally be implemented in all kinds of machines, motors or generators. As is known, in the case of a motor, the electrical energy supplied to the stator (62) can be converted into mechanical torque, by means of which the consumer can be driven via the output element (78) by the mechanical shaft (12), whereas in the case of a generator, the rotational movement imposed on the mechanical shaft (12) is used for the generation of electrical energy.

Explanation of reference numerals

[0039] 10 Assembly 12 Mechanical shaft 14 Shaft hole 16 Housing block 18 Shaft shoulder 20 Second rolling bearing 22 Inner ring 24 Outer ring 26 Ball 28 Control device 30 Bearing housing 32 Support shoulder 34 Spring element 36 Fastening part 38 Signal receiver 40 Signal generator 42 Retaining cup 44 Magnet, generator element 46 Fixed part 48 Generator housing part 50 Pressing flange 52 Fastening ring, tolerance ring 60 Stator housing 62 Stator 64 Rotor 66 First rolling bearing 68 Inner ring 70 Outer ring 72 First bearing seat 74 Housing cover 76 Second bearing seat 78 Output element 80 Pressing tool

Claims

1. A machine shaft (12) drivable for rotational movement, and at least one rolling bearing (20) for rotatably supporting the machine shaft (12) in a housing block (16), the rolling bearing having an inner ring (22) carrying the machine shaft (12) and an outer ring (24) assigned thereto and received in a bearing receiving portion (30) of the housing block (16), a signal generator (40) of a position detection sensor system for detecting the rotational angle of the machine shaft (12), the signal generator having a holding cup (42) and a generator element (44) arranged in the holding cup (42), in an assembly (10) comprising a fastening ring (52) which enters an annular gap between the inner circumference of the holding cup (42) and the outer circumference of the machine shaft (12) and fixedly attaches the signal generator (40) to the tip of the machine shaft (12) in a non-rotatable and axially immovable manner, the assembly, characterized in that one end of the fastening ring (52) axially protrudes from the holding cup (42) of the signal generator (40), and the protruding end is axially supported on a side surface of the inner ring (22) of the rolling bearing (20).

2. The bearing receiving portion (30) of the housing block (16) forms a support shoulder (32) located on the opposite side of the opening of the shaft hole (14) and axially supports a spring element (34), the spring element (34) applying an axial force in a direction opposite to the support force with which the fastening ring (52) is supported on the side surface of the inner ring (22) of the rolling bearing (20) to the outer ring (24) of the rolling bearing (20), the assembly according to claim 1.

3. The assembly according to claim 1 or 2, characterized in that the elastic spring element (34) is a wave washer.

4. The holding cup (42) is a sleeve-shaped member open on both sides and divided into a fixed portion (46) at the tip and a generator receiving portion (48) for the generator element (44) at the tip located on the opposite side of the tip, the holding cup (42) having an inner diameter smaller in the region of the fixed portion (46) than in the region of the generator receiving portion (48), the assembly according to any one of claims 1 to 3.

5. The assembly according to claim 4, characterized in that the generator element (44) includes a magnet, and the magnet axially abuts against a transition portion from the generator housing portion (48) to the fixed portion (46) inside the holding cup (42).

6. The inner ring (22) of the second rolling bearing (20) is arranged on the machine shaft (12) by means of a clearance fit, and The outer ring (24) of the rolling bearing (20) is accommodated in the assigned bearing housing portion (30) of the housing block (16) by means of a clearance fit. The assembly according to any one of claims 2 to 5, characterized by the above.

7. A method for manufacturing an assembly according to any one of the features of claims 1 to 6, Providing a housing block (16) comprising a shaft hole (14), a bearing housing portion (30), and an electromechanical machine having a machine shaft (12) attached to the housing block (16) and protruding into the shaft hole (14) of the housing block (16); Assembling the spring element (34) into the bearing housing portion (30) of the housing block (16) until the ring-shaped spring element (34) rests on a support shoulder (32) formed on the housing block (16); Steps of fitting a rolling bearing (20) externally on the machine shaft (12) by means of an inner ring (22), and inserting the second rolling bearing (20) into the bearing housing portion (30) of the housing block (16) until the second rolling bearing (20) abuts against the spring element (34) by means of a side surface of the outer ring (24); Fitting a fastening ring (52) onto the machine shaft (12) until the leading end axially abuts against the inner ring (22) of the rolling bearing (20); Pressing the signal generator (40) against the circumference of the fastening ring (52) by applying an axial force to the signal generator (40), such that the fastening ring (52) is displaced along the machine shaft (12) together with the second rolling bearing (20), and the spring element (34) is axially biased, and pressing until the rolling bearing (20) abuts against a shaft shoulder (18) formed on the machine shaft (12). A method, comprising the step of displacing the signal generator (40) relative to the fastening ring (52) to an end position in which a maximum overlap between the signal generator (40) and the fastening ring (52) is achieved and the fastening ring (52) is supported by the inner ring (22) of the second rolling bearing (20) by an end protruding from the holding cup (42) of the signal generator (40). Claim 8 An electronically commutated motor, in particular for a controllable drive of a brake pressure generating device of an electronically slip-controllable brake system of a motor vehicle, characterized in that the electronically commutated motor comprises the mounting assembly (10) according to any one of claims 1 to 6.

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