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EP-4737233-A1 - DISTRIBUTOR AND HYDRAULIC BRAKING SYSTEM OF AN AGRICULTURAL OR FORESTRY VEHICLE

EP4737233A1EP 4737233 A1EP4737233 A1EP 4737233A1EP-4737233-A1

Abstract

A distributor and an hydraulic braking system of an agricultural or forestry machine having: a main line (L1) in which, in use, oil flows at a pressure greater than or equal to 11.5 MPa; a supplementary line (L2) in which, in use, oil flows at a pressure less than or equal to 3.5 MPa; a main outlet (U1) connectable to a high pressure line of a towed vehicle; and a supplementary outlet (U2) connectable to a low pressure line of a towed vehicle; wherein, the distributor (1; 101; 201) comprises a main brake valve (4; 104) and a main pilot valve (7) which are arranged, along the main line (L1); wherein, the main brake valve (4; 104) is interposed between the main inlet (I1) and the main pilot valve (7); wherein, the main pilot valve (7) is interposed between the main brake valve (4; 104) and the main outlet (U1); wherein, the main pilot valve (7) is controlled by the main control (6).

Inventors

  • MAMEI, ENRICO
  • MAMEI, ANDREA

Assignees

  • Slanzi Oleodinamica S.r.l.

Dates

Publication Date
20260506
Application Date
20251104

Claims (9)

  1. An hydraulic brake distributor of an agricultural or forestry machine having: a main line (L1) crossed, in use, by oil at a first pressure, in particular a maximum pressure greater than or equal to 11.5 MPa; and a supplementary line (L2) crossed, in use, by oil at a second pressure, in particular a pressure less than or equal to 3.5 MPa; a main outlet (U1) connectable to a high pressure line of a towed vehicle; and a supplementary outlet (U2) connectable to a low pressure line of a towed vehicle; wherein, the distributor (1; 101; 201) comprises a main brake valve (4; 104) and a main pilot valve (7) which are arranged, along the main line (L1) ; wherein, the main brake valve (4; 104) is interposed between the main inlet (I1) and the main pilot valve (7); wherein, the main pilot valve (7) is interposed between the main brake valve (4; 104) and the main outlet (U1); wherein, the main pilot valve (7) is controlled by the main control (6).
  2. A distributor according to claim 1, wherein the main pilot valve (7) has: a rest position (S5), a first working position (S6), in which it lowers the oil pressure towards the main outlet (U1) and a second working position (S7), in which it increases the oil pressure towards the main outlet (U1).
  3. A distributor according to claim 2, and having a discharge outlet (U3) connectable to a discharge (T); wherein, when the main pilot valve (7) is in the rest position (S5), the main outlet (U1) is placed in communication via the main pilot valve (7) with the discharge outlet (U3).
  4. A distributor according to claim 1 or 2, wherein the main brake valve (4; 104) is a slide valve; wherein the main brake valve (4; 104) has one or more delivery positions (S1) and one or more discharge positions (S2).
  5. A distributor according to claim 4, wherein the main inlet (I1) is in fluidic communication with the main outlet (U1) via the main pilot valve (7) and the main brake valve (4; 104) when: the main pilot valve (7) is in a working position (S6; S7) and the main brake valve (4; 104) is in the delivery position (S1).
  6. A distributor according to any one of the preceding claims and comprising a supplementary brake valve (5) arranged along the supplementary line (L2); wherein, the distributor (1; 101; 201) further comprises a supplementary pilot valve (10), which is configured to operate the supplementary brake valve (5) as a function of the pressure along the main line (L1) and of the calibration of an actuator (A4).
  7. A distributor according to claim 6, wherein the main control (6) is configured to directly operate the supplementary pilot valve (10); in particular, the main control (6) is configured to operate in parallel and simultaneously both the main pilot valve (7) and the supplementary pilot valve (10).
  8. A distributor according to claim 6 or 7 and having a signal line (L3), which puts in fluidic communication one way of the main pilot valve (7) with: a first actuator (A2) of the main brake valve (4); a second actuator (A5) of the main pilot valve (7); and, a third actuator (A6) of the supplementary pilot valve (10).
  9. An hydraulic braking system of an agricultural or forestry machine comprising a hydraulic distributor (1; 101; 201) according to any one of the preceding claims.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority from Italian patent application no. 102024000024759 filed on November 5, 2024, the entire disclosure of which is incorporated herein by reference. TECHNICAL FIELD The present invention relates to a distributor and to a hydraulic braking system of an agricultural or forestry machine. PRIOR ART It is known that an agricultural or forestry machine must be provided with a main line crossed by high pressure oil and a secondary line crossed by low pressure oil separate from one another, so that one line can ensure the braking of the towed vehicle also in case of malfunctioning of the other line. Known examples of distributors and hydraulic systems that implement the solution described above are described in EP3064408 B1 and in EP3202629 B1. DESCRIPTION OF THE INVENTION The object of the present invention is to provide an improved distributor and an improved hydraulic braking system. According to the present invention, a distributor and a hydraulic braking system are provided according to what is claimed in the appended claims. The dependent claims define particular embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the invention, embodiments thereof are described in the following by way of non-limiting example and with reference to the accompanying drawings wherein: Figure 1 is a schematic view, with some parts removed for clarity, of a distributor according to the present invention; and,Figure 2 illustrates, in a schematic manner and with some parts removed for clarity, an example of a system according to the present invention;Figure 3 illustrates, in a schematic manner and with some parts removed for clarity, a variant of a system according to the present invention;Figure 4 illustrates, in a schematic manner and with some parts removed for clarity, a further variant of a system according to the present invention. EMBODIMENTS OF THE INVENTION In Figure 1, the reference numeral 1 is used for a hydraulic brake distributor of an agricultural or forestry machine (of known type and not illustrated), in particular for the braking of a towed vehicle (of known type and not illustrated) coupled to the agricultural or forestry machine. The distributor 1 is a component of a hydraulic braking system 2 of the tractor. In particular, the hydraulic system 2 is configured, as will be better illustrated in the following, to send high pressure oil along a main line L1 and low pressure oil along a supplementary line L2 to the towed vehicle. Figure 2 illustrates the diagram of an embodiment of the hydraulic system 2 of an agricultural or forestry machine comprising a distributor 1 according to the present invention. In particular, the distributor 1 comprises: a main inlet I1 connectable (in a known manner and schematically illustrated) to a main delivery P1 of high pressure oil; a supplementary inlet I2 connectable (in a known manner and schematically illustrated) to a supplementary delivery P2 of low pressure oil; a main outlet U1 connectable (in a known manner and schematically illustrated) to the high pressure line of a towed vehicle; and a supplementary outlet U2 connectable (in a known manner and schematically illustrated) to a low pressure line; a discharge outlet U3 connectable (in a known manner and schematically illustrated) to a discharge T. The main delivery P1 is configured to feed oil at a pressure up to at least 11.5 Mpa to the main line L1. The supplementary delivery P2 is configured to feed the supplementary line L2. Preferably, the supplementary delivery P2 continuously feeds oil at a pressure less than or equal to 3.5 MPa. The distributor 1 comprises a body 3 inside which chambers and conduits are made for the passage of oil and the housing of valves, as illustrated in the following. In particular, according to the example illustrated in Figure 2, the distributor 1 comprises a main brake valve 4 arranged, along the main line L1, between the main inlet I1 and the main outlet U1. The main brake valve 4 is configured to selectively send, in use, high pressure oil to the towed vehicle, as will be better illustrated in the following. The main brake valve 4 is crossed by the line L1 and is connected to the discharge outlet U3 when it is in a discharge position S2, as will be better illustrated in the following. The main brake valve 4 can be chosen within a group of valves different from one another by type. According to the illustrated example, the main brake valve 4 is a two-position, three-way slide valve. In the example of Figure 2, the main brake valve 4 has a delivery position S1 and a discharge position S2. According to the variants (Figure 3), the main brake valve 4 has a plurality of delivery positions S1. The main brake valve 4 comprises an actuator A1, which is operable as a function of the pressure along the main line LI between the valve 4 and the valve 7, and an actuator A2, which is op