Gearwheel set for a transmission

Abstract

In a gearwheel set for a transmission, in particular for a transmission with a PTO (Power Take-Off) accessory, at least two gearwheels (6, 10) bearing against one another, and the gearwheels (6, 10) being rotatable in relation to one another, and both gearwheels (6, 10) having recesses (8.1-8.3; 11.1-11.3) which form with one another a reception space for an actuator (1), the actuator (1) is to be radially movable in the reception space, and the recesses (8.1-8.3; 11.1-11.3) are to have a different shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and details of the invention may be gathered from the following description of preferred exemplary embodiments and with reference to the drawing in which:

FIG. 1 shows a side view of an actuator for a wheel set according to the invention;

FIG. 2 shows a top view of the actuator according to FIG. 1;

FIG. 3 shows a top view of a basic wheel of a gearwheel set according to the invention;

FIG. 4 shows a section through FIG. 3 along the line IV-IV;

FIG. 5 shows a top view of a tension wheel according to the invention;

FIG. 6 shows a section through the tension wheel according to FIG. 5 along the line VI-VI;

FIG. 7 shows a partially illustrated detail from a gearwheel set according to the invention;

FIG. 8 shows a top view of the detail of the gearwheel set according to FIG. 7 in a further position of use.

DETAILED DESCRIPTION

FIGS. 1 and 2 show an actuator 1 which consists of a base 2 and of a sliding block 3. Both are connected to one another in one piece and produced, for example, from metal. However, another material, such as, in particular, ceramic, may also be envisaged here.

The base 2 has a width b and possesses a major axis A of length l. By contrast, the sliding block 3 is designed with a smaller width, this taking place by means of a setback 4. A sliding surface 5 is thereby formed, which runs at an angle w with respect to the major axis A.

FIG. 3 shows a top view of a basic wheel 6 possessing a circumferential toothing, of which only one tooth 7 is indicated. This basic wheel 6 has formed integrally in it three recesses 8.1, 8.2 and 8.3 which are designed identically and are offset in each case through 120 with respect to one another. Each recess 8.1 to 8.3 has an elliptical shape with a width b₁ and a length l₁. A major axis A₁ runs in this case in the direction of a radius R which runs radially outward from a center point M of the basic wheel 6. Two likewise radially running sidewalls 9.1 and 9.2 of the recesses 8.1 to 8.2 run at least partially parallel to one another and approximately parallel to the radius R.

A tension wheel 10 illustrated in FIGS. 5 and 6 likewise possesses three recesses 11.1 to 11.3 which again are designed identically and are arranged so as to be offset through 120° with respect to one another. Each of these recesses 11.1 to 11.3 possesses a shape which is elliptical in the widest sense, although a width b₂ is smaller than the width b₁ of the recesses 8.1 to 8.3. By contrast, a length l₂ corresponds approximately to the length l₁ of the recesses 8.1 to 8.3.

It is essential in this case that a major axis A₂ runs at an angle b₁ with respect to the radius R. The two sidewalls 12.1 and 12.2 likewise run at an angle with respect to the radius R.

The functioning of the present invention is explained in more detail with reference to FIGS. 7 and 8. It can be seen in this case that the recess 8 of the basic wheel 6 is located below, but in the region of the recess 11 of the tension wheel 10. The actuator 1 is seated with its base 2 in the elliptical recess 8. However, since its length l is smaller than the length l₁ of the recess 8, the actuator 1 can move radially in the direction of the double arrow 13 of the recess 8.

The actuator 1 engages with the sliding block 3 into the other recess 11, the sliding surface 5 of the sliding block 3 bearing against an obliquely set sidewall 12.1 of the recess 11.

If the gearwheel set 6/10 is then set in rotational movement, the actuator 1 presses outward under the action of the centrifugal force. If, for example, the actuator weighs 5 g, this weight increases to about 100 kg due to the centrifugal force at about 4000 revolutions of the gearwheel set. Under this weight, the actuator 1, when it slides radially outward, also presses with the sliding surface 5 against the sidewall 12.1 of the tension wheel 10. At the same time, the base 2 slips radially outward in the recess 8, so that the tension wheel 10 is rotated by an amount in relation to the basic wheel 6. An offset of the tooth 7.1, indicated by dots, of the tension wheel 10 with respect to the tooth 7 of the basic wheel 6 thereby takes place. As a result, a possible play in a gearwheel transmission is compensated. The offset takes place through the angle w₂.

As soon as the rotational speed of the gearwheel set is reduced, the actuator 1 should also move back into its initial position again. This takes place preferably under the pressure of a helical spring, not shown in any more detail, which is inserted into a blind hole 14, indicated by dashes, in the actuator 1 and preferably in the base 2 there.

An essential parameter of the present invention is the angle w₁ or w at which the sliding surface 5 or the major axis A₂ of the recess 11 is set with respect to the radius R. The larger this selected angle becomes, the less pressure can be exerted on the tension wheel.

Claims

1. Gearwheel set for a transmission with a PTO (Power Take-Off) accessory, comprising at least two gearwheels (6, 10) bearing against one another, wherein the gearwheels (6, 10) are rotatable relative to one another, and both gearwheels (6, 10) have recesses (8.1-8.3; 11.1-11.3) which form a reception space for an actuator (1), the actuator (1) is radially movable in the reception space, and the recesses (8.1-8.3; 11.1-11.3) have different shapes.

2. Gearwheel set according to claim 1, wherein a width (b1, b2) of the recesses (8.1-8.3; 11.1-11.3) transverse to a radial orientation are different.

3. Gearwheel set according to claim 1, wherein a radial length (l1, l2) of the recesses (8.1-8.3; 11.1-11.3) are approximately identical.

4. Gearwheel set according to claim 1, wherein a first recess (8.1-8.3) is shaped approximately elliptically, the major axis (A1) running radially in the gearwheel (6).

5. Gearwheel set according to claim 4, wherein two sidewalls (9.1, 9.2) of the ellipse, which normally form the secondary vertices, run at least partially in parallel.

6. Gearwheel set according to claim 4, wherein another recess (11.1-11.3) is shaped elliptically has a minor axis with a smaller length than the minor axis of the first recess (8.1-8.3).

7. Gearwheel set according to claim 6, wherein a major axis (A2) of the other recess (11.1-11.3) runs at an angle (w1) with respect to a radius (R) of the gearwheel (10).

8. Gearwheel set according to claim 7, wherein two sidewalls (12.1, 12.2) of the other recess (11.1-11.3) which normally form the secondary vertices, run at least partially in parallel and run at the angle (w1) with respect to the radius (R).

9. Gearwheel set according to claim 4, wherein the actuator (1) has a length (l) which is smaller than a length (l1, l2) of the recesses (8.1-8.3; 11.1-11.3).

10. Gearwheel set according to claim 9, wherein the actuator (1) has a base (2) and a sliding block (3).

11. Gearwheel set according to claim 10, wherein the base (2) has a circumference which corresponds approximately to the circumference of the first elliptical recess (8.1-8.3), but with a shorter length (l) of the radial major axis (A).

12. Gearwheel set according to claim 10, wherein the sliding block (3) has a sliding surface (5) which is set at an angle (w) with respect to the radius (R) and which co-operates with one of the sidewalls (12.1) of the other recess (11.1-11.3).

13. Gearwheel set according to claim 10, wherein the base (2) and sliding block (3) are produced in one piece.

14. Gearwheel set according to claim 1, wherein the actuator (1) is supported in a recess (8.1-8.3; 11.1-11.3) via at least one force accumulator.

15. Gearwheel set according to claim 14, wherein the force accumulator acts on the actuator (1) counter to the centrifugal force.